GB2432190A

GB2432190A - Hinge device

Info

Publication number: GB2432190A
Application number: GB0703255A
Authority: GB
Inventors: Manabu Hasegawa
Original assignee: Sugatsune Kogyo Co Ltd
Current assignee: Sugatsune Kogyo Co Ltd
Priority date: 2004-07-30
Filing date: 2005-07-19
Publication date: 2007-05-16
Anticipated expiration: 2025-07-19
Also published as: WO2006011390A1; GB2432190B8; GB0703255D0; CN1993559A; JP2006046382A; GB2432190A8; GB2432190B; KR20070042189A

Abstract

A hinge device is provided with a device main body (20), a hinge member (30) turnably arranged on the device main body (20) with a turning axis line at the center, a movable member (50) which is arranged on the device main body (20) not to be turned but movable in the turning axis line direction, and a coil spring (60) for urging the movable member (50) to the side of the hinge member (30). An intermediate member (70) is provided between the hinge member (30) and the movable member (50). The intermediate member (70) is permitted to turn on the hinge member (30) within a range of a prescribed first angle and to turn on the movable member (50) within a range of a prescribed second angle.

Description

DESCRIPTION

HINGE ASSEMBLY

TECHNICAL FIELD

[00011 This invention relates to a hinge assembly suitable for use, for example, in a mobile phone handset in which a transmission section and a reception section can be rotated through a large angle.

BACKGROUND ART

[00021 Patent Document 1 shown below discloses a hinge assembly in accordance with the prior art. The hinge assembly comprises a hinge member, a movable member connected to the hinge member such that the movable member is rotatable about a rotation axis and movable in a direction of the rotation axis and biasing means biasing the movable member toward the hinge member. A pair of spherical bodies is provided on an end surface of the movable member opposing the hinge member and arranged on a circle about the rotation axis degrees away from each other in a circumferential direction. A pair of first recesses and a pair of second recesses are formed in an opposing surface of the hinge member facing the movable member.

The pair of spherical bodies enters the pair of first recesses when the hinge member is in a predetermined first rotation position and the pair of spherical bodies enters the pair of second recesses when the hinge member is in a second rotation position away from the first rotation position by a predetermined angle.

Patent Document 1: Japanese Unexamined Patent Application Publication No. H 11-50727.

DISCLOSURE OF THE INVENTION

PROBLEM TO BE SOLVED BY THE INVENTION

[0003] In a case where the first rotation position and the second rotation position of the hinge member are separated by 180 degrees or more, the first recesses and the second recesses need to be arranged offset in a radial direction of a second hinge member. This is because otherwise the first recesses and the second recesses might overlap with each other or the spherical bodies might move in and out of the first and second recesses while the hinge member is rotating between the first rotation position and the second rotation position, resulting in the hinge member not being able to be rotated smoothly.

Arranging the first and second recesses offset in the radial direction, however, requires the hinge member and the movable member to be larger in outer diameter to accommodate such an arrangement, which in turn makes the hinge assembly larger in diameter.

MEANS FOR SOLVING THE PROBLEM

[0004] In order to solve the above-mentioned problem, a first aspect of the present invention provides a hinge assembly comprising a hinge member, a movable member connected to the hinge member such that the movable member is rotatable about a rotation axis and movable to and from the hinge member in a direction of the rotation axis and biasing means biasing the movable member toward the hinge member, characterized in that an intermediate member is provided between the hinge member and the movable member such that the intermediate member is rotatable about the rotation axis and movable in the direction of the rotation axis, the movable member is abutted against the intermediate member by a biasing force of the biasing means, the intermediate meniber is abutted against the hinge member by the biasing force of the biasing means, the intermediate member is rotatable within a predetermined first angular range with respect to the hinge member, and the intermediate member is rotatable within a predetermined second angular range with respect to the movable member.

In this case, it is preferable that a first conversion mechanism is provided at least one of between the hinge member and the intermediate member and between the movable member and the intermediate member, the first conversion mechanism converting the biasing force of the biasing means into a rotational-biasing force for rotationally biasing the hinge member in a direction from one end toward the other end within the first angular range when the intermediate member is in one end portion within the first angular range with respect to the hinge member and in one end portion within the second angular range with respect to the movable member.

It is preferable that a second conversion mechanism is provided at least the other of between the hinge member and the intermediate member and between the movable member and the intermediate member, the second conversion mechanism converting the biasing force of the biasing means into a rotational-biasing force for rotationally biasing the hinge member in a direction from the other end toward one end within the first angular range when the intermediate member is in the other end portion within the first angular range with respect to the hinge member and in the other end portion within the second angular range with respect to the movable member.

In order to solve the above-mentioned problem, a second aspect of the present invention provides a hinge assembly comprising a first hinge member arranged on a first rotation axis; a second hinge member arranged on a second rotation axis parallel to the first rotation axis; a first movable member connected to the first hinge member such that the first movable member is rotatable about the first rotation axis and movable to and from the first hinge member in a direction of the first rotation axis; a second movable member connected to the second hinge member such that the second movable member is rotatable about the second rotation axis and movable to and from the second hinge member in a direction of the second rotation axis; a first intermediate member provided between the first hinge member and the first movable member such that the first intermediate member is rotatable about the first rotation axis and movable in the direction of the first rotation axis; a second intermediate member provided between the second hinge member and the second movable member such that the second intermediate member is rotatable about the second rotation axis and movable in the direction of the second rotation axis; biasing means biasing the first and second movable members toward the first and second hinge members respectively, thereby bringing the first and second movable members into abutment with the first and second intermediate members respectively and bringing the first and second intermediate members into abutment with the first and second hinge members respectively; a first gear nonrotatably provided on the first hinge member; and a second gear non-rotatably provided on the second hinge member and meshing with the first gear, characterized in that the first intermediate member is rotatable within a predetermined first angular range with respect to the first hinge member and rotatable within a predetermined second angular range with respect to the first movable member, and the second intermediate member is rotatable within a predetermined third angular range with respect to the second hinge member and rotatable within a predetermined fourth angular range with respect to the second movable member.

In this case, it is preferable that the hinge assembly further comprises an assembly main body rotatably Supporting the first and second rotatable members. It is preferable that the assembly main body is formed in a circular cylindrical configuration and that the first and second hinge members on which the first and second gears are respectively provided, the first and second intermediate members, the first and second movable members and the biasing means are received in the hinge member.

It is preferable that a first conversion mechanism is provided in one or more of the following locations: between the first hinge member and the first intermediate member, between the first intermediate member and the first movable member, between the second hinge member and the second intermediate member and between the second intermediate member and the second movable member, the first conversion mechanism converting the biasing force of the biasing means into a rotational-biasing force for rotationally biasing the first hinge member in a direction from one end toward the other end within the first angular range or into a rotational-biasing force for rotationally biasing the second hinge member in a direction from one end toward the other end within the third angular range when the first intermediate member is in one end portions within the first and second angular ranges and the second intermediate member is in one end portions within the third and fourth angular ranges.

It is preferable that a second conversion mechanism is provided in one or more of the following locations: between the first hinge member and the first intermediate member, between the first intermediate member and the movable member, between the second hinge member and the second intermediate member and between the second intermediate member and the second movable member, the second conversion mechanism converting the biasing force of the biasing means into a rotational-biasing force for rotationally biasing the first hinge member in a direction from the other end toward one end within the first angular range or into a rotational-biasing force for rotationally biasing the second hinge member in a direction from the other end toward one end within the third angular range when the first intermediate member is in the other end portions within the first and second angular ranges and the second intermediate member is in the other end portions within the third and fourth angular ranges.

EFFECT OF THE INVENTION

[00051 According to the first aspect of the present invention having the above-described construction, since the intermediate member is rotatable within the first angular range with respect to the hinge member and is rotatable within the second angular range with respect to the movable member, the hinge member is rotatable within a range of angle that is the sum of the first angular range and the second angular range with respect to the movable member. Thus, the hinge member is movable in a wide range of angle. For example, when the first angular range and the second angular range are 90 degrees respectively, the hinge member is rotatable 180 degrees with respect to the movable member. Moreover, since the hinge member is rotatable only 90 degrees with respect to the intermediate member, when a pair of projections is formed in either one of abutment surfaces of the hinge member and the intermediate member and a pair of first recesses and a pair of second recesses are formed in the other of the abutment surfaces of the hinge member and the intermediate member, the first and second recesses are separated by only 90 degrees, not needing to be separated by 180 degrees, in a circumferential direction. Accordingly, the first and second recesses need not be arranged apart from each other in a radial direction but can be arranged on a same circumference The same applies to abutment surfaces of the intermediate member and the movable member. Therefore, it is not necessary for the hinge member, the movable member and the intermediate member to be large in outer diameter. Thus, the hinge assembly does not have to be large in diameter.

A similar effect is also obtained in the second aspect.

BRIEF DESCRIPTION OF DRAWINGS

[00061 FIG. 1 is a perspective view of a mobile phone handset in which a hinge assembly according to the present invention is used with a second housing of the hinge assembly rotated to a fully-open position.

FIG. 2 is an exploded perspective view of the above mobile phone handset.

FIG. 3 is a side view of a first embodiment of the hinge assembly according to the present invention.

FIG. 4 is a plan view of the above hinge assembly.

FIG. 5 is a view on arrow X of FIG. 3.

FIG. 6 is a sectional view taken on line X-X of FIG. 4.

FIG. 7 is a perspective view of the above hinge assembly.

FIG. 8 is an exploded perspective view of the above hinge assembly FIG. 9 shows a hinge member used in the above hinge assembly: FIG. 9(A) is a perspective view thereof; and FIG. 9(B) is a plan view thereof.

FIG. 10 shows an intermediate member used in the above hinge assembly: FIG. 10(A) is a plan view thereof; FIG. 10 (B) is a sectional view taken on line B-B of FIG. 10 (A); FIG. 10 (C) is a view on arrow C of FIG. 10(A); FIG. 10(D) is a view on arrow D of FIG. 10 (A); FIG. 10(E) is a perspective view of the intermediate member viewed from one direction; and FIG. 10(F) is a perspective view of the intermediate member viewed from the other direction.

FIG. 11 is a side view of the mobile phone handset of FIG. 1 with the second housing rotated to a folded position.

FIG. 12 is a side view of the mobile phone handset of FIG. 1 with the second housing rotated to an intermediate position.

FIG. 13 is a side view of the mobile phone handset of FIG. 1 with the second housing rotated to a fully-open position.

FIG. 14 is a development view showing relationships among the hinge member, the intermediate member and a spherical body provided in a movable member used in the first embodiment of the hinge assembly according to the present invention; FIG. 14(A) shows relationships thereamong when the hinge member is in a folded position; FIG. 14(B) shows relationships thereamong when the hinge member is rotated from the folded position to an intermediate position; FIG. 14(C) shows relationships thereamong when the hinge member is rotated to a fully-open position; FIG. 14(D) shows relationships thereamong when the hinge member is rotated from the fully-open position to the intermediate position; and FIG. 14(E) shows relationships thereamong when the hinge member is rotated from the intermediate position to the folded position.

FIG. 15 is a view showing relationships among a hinge member, an intermediate member and a spherical body provided in a movable member used in a second embodiment of the hinge assembly according to the present invention. FIGS. 15(A) through 15(E) are similar to figures 14(A) to 14(E) respectively.

FIG. 16 is a side view of a mobile phone handset in which a hinge assembly according to a third embodiment of the present invention is used, with a second housing of the mobile phone handset rotated to a folded position.

FIG. 17 is a side view of the above mobile phone handset with the second housing thereof rotated from the folded position to an intermediate position.

FIG. 18 is a side view of the above mobile phone handset with the second housing thereof rotated to a fully-open position.

FIG. 19 is a side view of the above mobile phone handset with the second housing thereof rotated from the fully-open position to a second intermediate position.

FIG. 20 is a development view showing relationships among a hinge member, an intermediate member and a spherical body provided in a movable member used in the third embodiment; FIG. 20(A) shows relationships thereamong when the hinge member is in a folded position; FIG. 20(B) shows relationships thereamong when the hinge member is rotated from the folded position to an intermediate position; FIG. 20(C) shows relationships thereamong at a moment when the hinge member reaches a fully-open position from the folded position; FIG. 20(D) shows relationships thereamong when the intermediate member is rotated through a predetermined angle from a folded position toward an intermediate position after the hinge member reached the fully-open position; FIG. 20(E) shows relationships thereamong when the hinge member is rotated from the fully-open position to a second intermediate position; FIG. 20(F) shows relationships thereamong at a moment when the hinge member reaches the folded position from the second intermediate position; and FIG. 20(G) shows relationships thereamong when the intermediate member is rotated through a predetermined angle from the folded position toward the fully-open position after the hinge member reached the folded position.

FIG. 2 1 shows a movable member used in a fourth embodiment of the hinge assembly according to the present invention: FIG. 2 1(A) is a plan view thereof; and FIG. 2 1(B) is a sectional view taken on line B-B of FIG. 21(A).

FIG. 22 shows an intermediate member used in the above embodiment: FIG. 22(A) is a plan view thereof; and FIG. 22(B) is a sectional view taken on line B-B of FIG. 22(A).

FIG. 23 shows a hinge member used in the above embodiment: FIG. 23(A) is a plan view thereof; and FIG. 23(B) is a sectional view taken on line B-B of FIG. 23(A).

FIG. 24 is a development view showing relationships among the hinge member, the intermediate member and the movable member used in the fourth embodiment: FIG. 24(A) shows relationships thereamong when the hinge member is in a folded position; and FIG. 24(B) shows relationships thereamong when the hinge member is in a fully-open position.

FIG. 25 is a perspective view of a mobile phone handset in which a hinge assembly according to a second aspect of the present invention is used with a second housing of the mobile phone handset rotated to an extended position.

FIG. 26 is an exploded perspective view of the above mobile phone handset.

FIG. 27 is an exploded perspective view of a unit housing the hinge assembly according to the second aspect of the present invention.

FIG. 28 is a perspective view of the above Unit.

FIG. 29 shows the above unit; FIG. 29(A) is a plan view thereof; FIG. 29(B) is a view on arrow B of FIG. 29(A); FUG. 29(C) is a view on arrow C of FIG. 29(C); and FIG. 29(D) is a sectional view taken on line D-D of FIG. 29(A).

FIG. 30 is an exploded perspective view of the above unit and the hinge assembly.

DESCRIPTION OF REFERENCE NUMERALS

hinge assembly assembly main body hinge member 33c first inclined bottom surface (first conversion mechanism) 33d second inclined bottom surface (second conversion mechanism) movable member coiled spring (biasing means) intermediate member 75a, 75b inclined surface (second conversion mechanism) 76 abutment protrusion (first conversion mechanism, second conversion mechanism) 80A, 80B spherical body (second conversion mechanism) hinge assembly 210 hinge cylinder (assembly main body) 230A first hinge member 230B second hinge member 231A first gear part (first gear) 231B second gear part (second gear) 250 movable member (first and second movable members) 260A first coiled spring (biasing means) 260B second coiled spring (biasing means) 270A first intermediate member 270B second intermediate member 272 abutment protrusion 290A, 290B spherical body (second conversion mechanism)

BEST MODE FOR CARRYING OUT THE INVENTION

[00081 Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

FIG. 1 shows a mobile phone handset A in which a hinge assembly according to the present invention is used. The mobile phone handset A comprises a first housing 1 constituting a transmission section and a second housing 2 constituting a reception section. The first housing 1 has a rectangular parallelepiped configuration. A connecting projection lb is formed in one end portion in a longitudinal direction of a front surface la of the first housing 1. The connecting projection lb extends in a short direction of the front surface Ia. A support hole ic is formed through the connecting projection lb form one end surface to the other end surface in a longitudinal direction of the connecting projection lb. On the other hand, as shown in FIG. 2, the second housing 2 has two half bodies 2A, 2B. The second housing 2 having a rectangular parallelepiped configuration is constituted by the two half bodies 2A, 2B superposed and fixed to each other. A recess 2c is formed in one end portion in a longitudinal direction of the second housing 2. The recess 2c extends through the second housing 2 from a front surface 2a to a rear surface 2b thereof. The connecting projection lb of the first housing 1 is rotatably inserted in the recess 2c. The first housing 1 and the second housing 2 are rotatably connected to each other at one end portions thereof through a hinge assembly 10 according to the present invention and a conventional hinge 3.

Another hinge assembly 10 may be used in place of the hinge 3.

[0009] As shown in FIGS. 3 through 8, the hinge assembly 10 includes an assembly main body 20 and a hinge member 30 rotatably connected to the assembly main body 20. The assembly main body is non-rotatably fitted to one end portion of the support hole ic.

The hinge member 30 is non-rotatably mounted in one side portion of the one end portion of the second housing 2, the one side portion being adjacent to the recess 2c. On the other hand, the hinge 3 includes, as shown in FIG. 2, a circular shaft part 3a having a circular cross-section and an angular shaft part 3b having a generally square cross-section and integrally provided on one end surface of the circular shaft part 3a. The circular shaft part 3a and the angular shaft part 3b are arranged coaxially with each other. The circular shaft part 3a is rotatably fitted into the other end portion of the support hole ic. The angular shaft part 3b is non-rotatably mounted in the other side portion of the one end portion of the second housing 2, the other side portion being adjacent to the recess 2a. A rotation axis of the assembly main body 20 and the hinge member 30 and an axis of the circular shaft part 3a and the angular shaft part 3b are aligned with one another. As a result, the first housing 1 and the second housing 2 are connected to each other through the hinge assembly 10 and the hinge 3 such that the first housing 1 and the second housing 2 are rotatable about the axis of the hinge assembly and the hinge 3. A range of rotation of the first and second housings 1, 2 relative to each other is restricted between a folded position in which the front surfaces la, 2a of the first and second housings are in abutment with each other (see FIG. ii) and a fully-open position in which the back surface 2b of the second housing 2 is in abutment with the front surface la of the first housing 1 (see FIG. 1) as a result of 180 degrees rotation of the second housing 2 with respect to the first housing 1 from the folded position. The second housing 2 is stopped with a predetermined amount of force at an intermediate position, which is at a predetermined angle (100 degrees in this embodiment) from the folded position toward the fullyopen position, by an action of the hinge assembly 10. For the sake of explanation, in the description below, it is assumed that the first housing 1 is non-rotatably fixed in position and the second housing 2 is rotated with respect to the first housing 1.

[00101 As shown in FIGS. 6 and 8, the hinge assembly 10 includes a hinge pin 40, a movable member 50, a coiled spring (biasing means) and an intermediate member 70 as well as the assembly main body and the hinge member 30 described above.

[00111 The assembly main body 20 is formed in a shape of a bottomed circular cylinder comprising a circular cylindrical main body part 2 1 and a bottom part 22 closing one end portion of the main body part 2 1.

The main body part 21 is non-rotatably fitted into the support hole Ic of the first housing 1. Accordingly, the assembly main body 20 is rotated in unison with the first housing 1. However, since it is assumed here that the first housing 1 is fixed in position without being rotated, the assembly main body 20 is not rotated, either. A pair of guide grooves 21a, 21a is formed in the main body part 21.

The pair of guide grooves 21a, 21a extends from an opening side end portion of the main body part 21 toward the bottom part 22. A through hole 22a is formed in a central portion of the bottom part 22.

The hinge pin 40 is rotatably inserted into the through hole 22a. A head part 41 is formed in one end portion of the hinge pin 40. The head part 41 is larger in diameter than the through hole 22a.

Abutment of the head part 41 against the outer end surface of the bottom part 22 prohibits movement of the hinge pin 40 in a direction from the bottom part 22 toward the opening portion of the assembly main body 20.

[00121 The other end portion of the hinge pin 40 extends to the opening side end portion of the main body part 21, where the hinge member 30 is fixed. As shown in FIGS. 6 through 9, the hinge member 30 includes a fitting part 31 and a connecting part 32 formed integrally with each other. The fitting part 31 is formed in a shape of disc. The other end portion of the hinge pin 40 is fixedly fitted to the central portion of the fitting part 31. At the same time, the fitting part 31 is rotatably fitted into the main body part 21 with an outer periphery of the fitting part 31 in contact with an inner periphery of the main body part 21. By this, the hinge member 30 is rotatably connected to the assembly main body 20. An escape recess 31a is formed in a central portion of an end surface of the fitting part 31, the end surface facing the assembly main body 20. The connecting part 32 is formed in a shape of a cylinder having a generally square cross-section and extends out of the main body part 21. The connecting part 32 is nonrotatably connected to the second housing 2. Accordingly, the hinge member 30 is rotated in unison with the second housing 2. Therefore, rotational positions of the hinge member 30 when the second housing 2 is in the folded position, the fully-open position and the intermediate position are also referred to as a folded position, a fully-open position and an intermediate position, respectively.

[0013] As shown in FIG. 6, the movable member 50 formed in a shape of disc is provided inside the main body part 21, to be more specific, in an intermediate portion in a longitudinal direction of the main body part 21 such that the movable member 50 is movable in a direction of the rotation axis of the assembly main body 20 and the hinge member (hereinafter referred to simply as a rotation axis). The hinge pin is inserted in a central portion of the movable member 50 with an annular gap therearound. A pair of engagement projections 5 1, 5 1 is formed in an outer peripheral surface of the movable member 50.

The engagement projections 51, 51 are slidably fitted to the guide grooves 21a, 21a of the main body part 21, respectively. By this, the movable member 50 is connected to the assembly main body 20 non-rotatably but movably in the direction of the rotation axis.

[0014] As shown in FIG. 6, an intermediate member 70 is provided inside the main body part 21. The intermediate member 70 is arranged between the movable member 50 and the hinge member 30.

As shown in FIGS. 6, 8 and 10, the intermediate member 70 includes an abutment part 71 having a disk-like configuration. The abutment part 71 is fitted into the main body part 21 rotatably and movably in the direction of the rotation axis. The hinge pin 40 is inserted in a central portion of the intermediate member 70 rotatably and movably in the direction the rotation axis. Accordingly, the intermediate member 70 is rotatable with respect to the assembly main body 20, the hinge member 30, the hinge pin 40 and the movable member 50 and movable in the direction of the rotation axis. A reinforcement cylindrical part 72 is formed on a first opposing surface 71a of the abutment part 71 facing the hinge member 30. Although the intermediate member 70 is biased toward the hinge member 30 by the coiled spring 60 as described later, the reinforcement cylindrical part 72 is not brought into abutment with the hinge member 30 since an outer diameter of the reinforcement cylindrical part 72 is slightly smaller than an inner diameter of the escape recess 31a of the hinge member 30. Afitting cylindrical part 73 is formed on a second opposing surface of the abutment part 71 facing the movable member 50. The fitting cylindrical part 73 is fitted in a central portion of the movable member 50 rotatably and movably in the direction of the rotation axis.

10015] As shown in FIG. 6, the coiled spring 60 is received inside the main body part 21. The coiled spring 60 is arranged between the bottom part 22 and the movable member 50 and biases the movable member 50 toward the intermediate member 70. The movable member 50 is brought into abutment with the second opposing surface 71b of the abutment part 71 of the intermediate member 70 by the biasing force of the coiled spring 60. Consequently, the intermediate member 70 is biased toward the hinge member 30 via the movable member 50 by the coiled spring 60. The first opposing surface 71a of the abutment part 71 is abutted against the hinge member 30.

Accordingly, the hinge member 30 is biased toward a direction away from the assembly main body 20 by the coiled spring 60. Since the hinge member 30 is fixed to the hinge pin 40 and the hinge pin 40 is prohibited from moving in a biasing direction of the coiled spring 60 by the abutment of the head part 41 of the hinge pin 40 with the bottom part 22, the hinge member 30 stays in the same position with respect to the assembly main body 20 without being moved by the coiled spring 60. Thus, the assembly main body 20, the hinge member 30, the hinge pin 40, the movable member 50, the coiled spring 60 and the intermediate member 70 constitute an assembly owing to the biasing force of the coiled spring 60.

[0016] As shown in FIGS. 6 and 8, a pair of spherical bodies 80A, 80B is partly embedded and fixed in an opposing surface of the movable member 50 facing the intermediate member 70 with portions of the spherical bodies 80A, 80B protruded from the movable member toward the intermediate member 70. The pair of spherical bodies 80A, 80B is arranged on the same circumference about the rotation axis 180 degrees away from each other in a circumferential direction.

The spherical bodies 80A, 80B may be rotatably embedded in the movable member 50. Alternatively, a pair of projections may be formed on the opposing surface of the movable member 50 facing the intermediate member 70 in place of the spherical bodies 80A, 80B.

[0017] As shown in FIG. 10, a pair of first engagement recesses 74A, 74B and a pair of second engagement recesses 75A, 75B are formed in the second opposing surface 71b of the intermediate member 70A facing the movable member 50. Bottom surfaces defining the pair of first engagement recesses 74A, 74B are concave spherical surfaces having the same radius of curvature as the spherical bodies 80A, 80B.

The depth of the first engagement recesses 74A, 74B is shallower than the amount of projections of the spherical bodies 80A, 80B out of the movable member 50. The pair of first engagement recesses 74A, 74B is arranged on the same circumference as the spherical bodies 80A, 80B when viewed from the direction of the rotation axis. The first engagement recesses 74A, 74B are arranged 180 degree away from each other in a circumferential direction. Therefore, when the intermediate member 70 is rotated to a predetermined first position with respect to the movable member 50, as shown in FIG. 14, portions of the pair of the spherical bodies 80A, 80B protruding out of the movable member 50 respectively fit in the first engagement recesses 74A, 74B. The pair of second engagement recesses 75A, 75B, too, is arranged on the same circumference of the circle as the spherical bodies 80A, 80B when viewed from the direction of the rotation axis.

The second engagement recesses 75A, 75B are arranged 180 degrees away from each other in a circumferential direction. The second engagement recesses 75A, 75B are respectively separated from the first engagement recesses 74A, 74B by a predetermined angle (80 degrees in this embodiment) in a circumferential direction. To be more specific, the second engagement recesses 75A, 75B are arranged such that in a condition in which the spherical bodies 80A, 80B are respectively fitted in the first engagement recesses 74A, 74B, if the intermediate member 70 is relatively rotated through the predetermined angle (80 degrees) in a direction of arrow A of FIG. 14 (direction from the folded position toward the fully-open position) with respect to the movable member 50, then the spherical bodies 80A, 80B respectively enter the second engagement recesses 75A, 75B and respectively contact inclined surfaces 75a, 75b of bottom surfaces defining the second engagement recess 75A, 75B. The inclined surfaces 75a, 75b are inclined downward toward a direction of arrow B of FIG. 14 (direction from the fully-open position toward the folded position).

[0018] Three abutment protrusions 76 are formed in the first opposing surface 71a of the intermediate member 70 facing the hinge member 30. Each of the abutment protrusions 76 extends from an outer peripheral surface of the reinforcement cylindrical part 72 towards an outer peripheral surface of the abutment part 71 along a radial direction of the abutment part 71. The abutment protrusions 76 are arranged equally spaced apart from each other, i.e., 120 degrees away from each other in the circumferential direction of the intermediate member 70. Alternatively, only two abutment protrusions 76 may be formed. In that case, two abutment protrusions 76 are arranged 180 degrees away from each other in the circumferential direction. A distal end portion of the abutment protrusion 76 is formed in a smooth convex surface such as a circular arcuate surface. On the other hand, abutment recesses 33 extending in a circumferential direction of the hinge member 30 are formed in an opposing surface of the hinge member 30 facing the intermediate member 70, as shown in FIG.9. The number of the abutment recesses 33 is the same as the number of the abutment protrusions 76, i.e., three. The three abutment recesses 33 are arranged in the circumferential direction equally spaced apart from each other.

[0019] As shown in FIGS. 9 and 14, the abutment recess 33 is defined by first and second end surfaces 33a, 33b located at opposite end portions of the abutment recess 33 in the circumferential direction of the hinge member 30 and a bottom surface located between the first and second end surfaces 33a, 33b. The bottom surface of the abutment recess 33 includes a first inclined bottom surface 33c having one end smoothly continuous with the first end surface 33a and inclined upward from the first end surface 33a in a direction of arrow B in FIG. 14, a second inclined bottom surface 33d having one end smoothly continuous with the second end surface 33b and inclined upward from the second end surface 33b in a direction of arrow A and a flat surface 33e formed between the first and second inclined bottom surfaces 33c, 33d as a flat surface orthogonal to the rotation axis. The fiat surface 33e lies on a same plane with the opposing surface of the hinge member 30 facing the intermediate member 70. Alternatively, the flat surface 33e may be arranged such that the flat surface 33e is away from the opposing surface in a direction from the intermediate member 70 toward the hinge member 30. The abutment protrusions 76 are respectively received in the abutment recesses 33. The abutment protrusion 76 is slidably moved on either one of the first inclined bottom surface 33c, the second inclined bottom surface 33d and the flat surface 33e in response to the relative rotation between the hinge member 30 and the intermediate member 70.

[0020] The relationship between the pair of the spherical bodies 80A, 80B and the first engagement recesses 74A, 74B, the relationship between the pair of the spherical bodies 80A, 80B and the second engagement recesses 75A, 75B and the relationship between the abutment protrusions 76 and the abutment recesses 33 will be described in detail hereinafter. Let us assume here that the second housing 2 and the hinge member 30 are in the folded position. When the second housing 2 is in the folded position, as shown in FIG. 14(A), the spherical bodies 80A, 80B are fitted in the first engagement recesses 74A, 74B and the abutment protrusion 76 is abutted against that portion of the first inclined bottom surface 33c which is adjacent to the first end surface 33a. A rotational position of the intermediate member 70 with respect to the hinge member 30 at this time is referred to as a first position and a rotational position of the intermediate member 70 with respect to the movable member 50 at this time is referred to as a third position. The first position of the intermediate member 70 with respect to the hinge member 30 is determined by the abutment of the front surface 2a of the second housing 2 against the front surface la of the first housing 1. When there is no such a restriction, alternatively, the first position of the intermediate member 70 with respect to the hinge member 30 may be determined by the abutment of the abutment protrusion 76 against the first end surface 33a.

[0021] When the second housing 2 and the hinge member 30 are in the folded position, the spherical bodies 80A, 80B are fitted in the first engagement recesses 74A, 74B. Moreover, the spherical bodies 80A, 80B are forced to be fitted in the first engagement recesses 74A, 74B by a biasing force of the coiled spring 60. Therefore, unless a rotational force greater than a predetermined amount is applied, the intermediate member 70 remains stationary with respect to the movable member 50 and thus with respect to the assembly main body 20. At the same time, the biasing force of the coiled spring 60 is converted into a rotationalbiasing force by the abutment protrusion 76 and the first inclined bottom surface 33c since the abutment protrusion 76 of the intermediate member 70 is in abutment with the first inclined bottom surface 33c. The rotational-biasing force acts on the hinge member 30 and the intermediate member 70 in opposite directions. However, this rotational-biasing force is smaller than the force required to bring the spherical bodies 80A, 80B out of the first engagement recesses 74A, 74B. Accordingly, the intermediate member 70 is maintained stationary by the movable member 50 without being rotated by the rotational-biasing force. Thus, the hinge member 30 alone is actually rotationally biased. In this case, the hinge member 30 is rotationally biased in the direction of arrow B (direction from the fully-open position toward the folded position).

By this rotational-biasing force, the second housing 2 is held in the folded position in which the second housing 2 is in abutment with the first housing 1. As is obvious from the foregoing, the first inclined bottom surface 33c and the abutment protrusion 76 constitute a first conversion mechanism that converts the biasing force of the coiled spring 60 into the rotational-biasing force for rotationally biasing the hinge member 30 in a direction from the fully-open position toward the folded position when the second hinge member 30 is in the folded position, that is when the intermediate member 70 is in the first position with respect to the hinge member 30 and in the third position with respect to the movable member 50.

[00221 When the hinge member 30 (second housing 2) is rotated from the folded position toward the fully-open position, the hinge member is rotated against the rotational-biasing force converted from the biasing force of the coiled spring 60. At this moment, a force acting to rotate the hinge member 30 from the folded position toward the fully-open position is transmitted to the intermediate member 70 through the abutment protrusion 76 in abutment with the first inclined bottom surface 33c and attempts to rotate the intermediate member 70 together with the hinge member 30 toward the fully-open position. However, when an inclination angle of the first inclined bottom surface 33c is l (see FIG. 14(D)) and an inclination angle of the bottom surface of the first engagement recess 74A (74B) at an intersecting portion with the second opposing surface 71b is al (see FIG. 14(C)), a1>1 is satisfied. Therefore, the intermediate member is not rotated together with the hinge member 30, and only the hinge member 30 is rotated from the folded position toward the fully-open position.

[0023] When the hinge member 30 is rotated through a predetermined angle (40 degrees in this embodiment) from the folded position, the abutment protrusion 76 moves past the first inclined bottom surface 33c and onto the flat surface 33e. Then, the abutment protrusion 76 is pressed against the flat surface 33e by the coiled spring 60, and consequently, frictional resistance acts therebetween. This frictional resistance causes the hinge member 30 and the second housing 2 to be stopped. The flat surface 33e has a length of generally 10 degrees in a circumferential direction. Accordingly, the hinge member 30 and the second housing 2 can be stopped at any position within an angular range of from 40 to 50 degrees away from the folded position. If the hinge member 30 is made to be able to be rotated freely before the abutment protrusion 76 moves past the first inclined bottom surface 33c, the hinge member 30 and the second housing 2 are brought back to the folded position by the rotational-biasing force of the coiled spring 60 converted by the first conversion mechanism.

[0024] When the hinge member 30 is rotated more than 50 degrees from the folded position, the abutment protrusion 76 is abutted against the second inclined bottom surface 33d. Then, the biasing force of the coiled spring 60 is converted into the rotational-biasing force for rotating the hinge member 30 in the direction of arrow A by the second inclined bottom surface 33d and the abutment protrusion 76. The hinge member 30 and the second housing 2 are rotated toward the fully-open position by this rotational-biasing force.

When the hinge member 30 is rotated through a predetermined angle (100 degrees in this embodiment) from the folded position, as shown in FIG. 14(B), the abutment protrusion 76 is abutted against the second end surface 33b. As a result, the hinge member 30 is prohibited from being rotated further with respect to the intermediate member 70. The rotational position of the intermediate member 70 at this moment with respect to the hinge member 30 is referred to as a second position. The intermediate member 70 is rotatable within a predetermined range of angle (100 degrees in this embodiment) between the first position and the second position with respect to the hinge member 30.

[00251 When the abutment protrusion 76 is in abutment with the second end surface 33b as described above, that is when the intermediate member 70 is in the second position with respect to the hinge member 30 and in the third position with respect to the movable member 50, the intermediate member 70 is prohibited from being rotated in the directions of arrows A and B by the fitting of the pair of spherical bodies 80A, 80B into the first engagement recesses 74A, 74B and the hinge member 30 is prohibited from being rotated in the direction of arrow A by the abutment of the abutment protrusion 76 against the second end surface 33b. At the same time, the hinge member 30 is biased toward the direction of arrow A by the rotational-biasing force of the coiled spring 60 converted by the abutment protrusion 76 and the second inclined bottom surface 33d.

Therefore, when the hinge member 30 is in the predetermined intermediate position in which the hinge member 30 is rotated through the predetermined angle (ioo degrees) from the folded position toward the fully-open position, the hinge member 30 is held in the intermediate position being prevented from movement in the direction from the fully-open position toward the folded position (direction of arrow B) by the rotational-biasing force of a predetermined magnitude converted from the biasing force of the coiled spring 60, and being prevented from movement in the direction from the folded position toward the fully-open position (direction of arrow A) by a force, a detail of which is described below, required to bring the pair of spherical bodies 80A, 80B out of the pair of the first engagement recesses 74A, 74B.

10026] When a rotational force greater than a predetermined magnitude is applied to the hinge member 30 in the direction of arrow A, the abutment protrusion 76 attempts to move over the second end surface 33b and the pair of the spherical bodies 80A, 80B attempt to escape from the first engagement recesses 74A, 74B against the biasing force of the coiled spring 60. Since inclination angles of a side surface of the abutment protrusion 76 and the second end surface 33b abutting against each other are specified to be much greater than the inclination angle al of the first engagement recesses 74A, 74B, the intermediate member 70 is rotated in unison with the hinge member 30 toward the fully-open position. When the hinge member and the second housing 2 are rotated 180 degrees from the folded position and reach the fully-open position, the second housing 2 is abutted against the first housing 1 and made to stop there.

Consequently, the hinge member 30 and the intermediate member 70 become unable to be further rotated in the direction form the folded position toward the fully-open position and stop their rotation.

When the hinge member 30 and the second housing 2 are in the fully-open position, as shown in FIG. 14 (C), the spherical bodies 80A, 80B are in abutment with the inclined surfaces 75a, 75b of the second engagement recesses 75A, 75B. A rotational position of the intermediate member 70 with respect to the movable member 50 at this moment is referred to as a fourth position. The intermediate member 70 is movable between the third position and the fourth position with respect to the movable member 50. The angle between the third position and the fourth position is specified to be 80 degrees in this embodiment. The fourth position of the intermediate member with respect to the movable member 50 is determined by the abutment of the second housing 2 against the first housing 1. In a case where there is no such a restriction, the fourth position of the intermediate member 70 with respect to the movable member 50 may be determined, for example, by the abutment of the spherical bodies 80A, 80B against an inclined surface 75c of the bottom surfaces of the second engagement recesses 75A, 75B. The inclined surface 75c is inclined in the opposite direction from the inclined surfaces 75a, 75b.

10027] When the hinge member 30 is in the fully-open position, in other words when the intermediate member 70 is in the second position with respect to the hinge member 30 and in the fourth position with respect to the movable member 50, the spherical bodies 80A, 80B are in abutment with the inclined surfaces 75a, 75b, and thus the biasing force of the coiled spring 60 is converted into the rotational-biasing force for rotationally biasing the intermediate member 70 in the direction of arrow A. Accordingly, the intermediate member 70 attempts to rotate in the direction of arrow A with respect to the hinge member 30. However, since an inclination angle 2 of the second inclined bottom surface 33d is specified to be greater than an inclination angle a2 of the inclined surface 75a (75b), the intermediate member 70 is not rotated in the direction of arrow A with respect to the hinge member 30. The rotational-biasing force acting on the intermediate member 70 is transmitted to the hinge member 30 through the abutment protrusion 76 and the second inclined bottom surface 33d. Consequently, the hinge member 30 is rotationally biased from the folded position toward the fully-open position and held in the fully-open position, at which time the second housing 2 is in abutment with the first housing 1. As is obvious from the above, the spherical bodies 80A, 80B and the inclined surfaces 75a, 75b constitute a second conversion mechanism.

[00281 If a hinge member 30 is rotated toward the folded position against the rotational-biasing force of the coiled spring 60 when the hinge member 30 and the second housing 2 are in the fully-open position, in other words, when the intermediate member 70 is in the second position with respect to the hinge member 30 and in the fourth position with respect to the movable member 50, the hinge member 30 remains stationary with respect to the intermediate member 70 and the intermediate member 70 is rotated from the fourth position toward the third position with respect to the movable member 50, because the inclination angle 132 of the second inclined bottom surface 33d is specified to be greater than the inclination angle u2 of the inclined surface 75a (75b). Consequently, the hinge member 30 and the intermediate member 70 are rotated toward the folded position (in the direction of arrow B) in unison. In response to the rotation of the intermediate member 70, the pair of spherical bodies 80A, 80B slidably moves on the inclined surfaces 75a, 75b and escapes from the second engagement recesses 75A, 75B relatively moving toward the first engagement recesses 74A, 74B.

[0029] When the intermediate member 70 reaches the third position, as shown in FIG. 14(D), the spherical bodies 80A, 80B fit in the first engagement recesses 74A, 74B, respectively. Consequently, since the angle ul is specified to be greater than the angle 132, the intermediate member 70 is stopped by the movable member 50 and only the hinge member 30 is rotated toward the folded position.

vVhen the hinge member 30 is further rotated toward the folded position, the abutment protrusion 76 moves past the flat surface 33e and onto the first inclined bottom surface 33c. Consequently, as described above, the biasing force of the coiled spring 60 is converted into the rotational-biasing force by the first inclined surface 33c, and by this rotational-biasing force, the hinge member 30 and the second housing 2 are rotated to the folded position and held in the folded position.

[00301 In the hinge assembly 10, when the second housing 2 is rotated degrees with respect to the first housing 1, the hinge member 30 is rotated 180 degrees with respect to the movable member 50 and the assembly main body 20. However, since the intermediate member 70 arranged between the hinge member 30 and the movable member 50 is rotated with respect to the hinge member 30 and the movable member 50, both the angle of rotation between the hinge member 30 and the intermediate member 70 and the angle of rotation between the movable member 50 and the intermediate member 70 are smaller than the angle of rotation between the hinge member 30 and the movable member 50. Consequently, three abutment recesses 33 formed in the hinge member 30 can be arranged on the same circumference and the pair of first engagement recesses 74A, 74B and the pair of second engagement recesses 75A, 75B both formed in the intermediate member 70 can be arranged on the same circumference.

Therefore, even though the rotation angle of the hinge member 30 with respect to the assembly main body 20 is as large as 180 degrees, the hinge member 30, the movable member 50 and the intermediate member 70 do not have to be large in diameter, thus the hinge assembly 10 can be prevented from being large in diameter.

[00311 Other embodiments of the present invention will now be described. Description will be given only on the components different from those of the above embodiment. Like components are denoted by like reference numerals with the above embodiment and will be explained in no more details.

FIG. 15 shows a second embodiment of the present invention.

In this embodiment, a pair of recesses 77 (only one of the recesses 77 is shown in FIG. 15) extending in a circumferential direction is formed in a second opposing surface 71b of the intermediate member facing the movable member 50. A bottom surface 77a of each recess 77 is a plane orthogonal to a rotation axis of a hinge member 30. A first engagement recess 74A, 74B for a spherical body 80A (80B) to fit in is formed in one end part in a circumferential direction of the bottom surface 77a of the recess 77. A distance in a circumferential direction between the first engagement recess 74A (74B) and the other end surface 77b of the recess 77 in a circumferential direction is specified to be slightly longer than a distance corresponding to an angular range of rotation of the intermediate member 70 with respect to the movable member 50.

Alternatively, these distances may be the same. Second engagement recesses 75A, 75B are not formed in this embodiment.

[0033] In this embodiment, when a second housing 2 and the hinge member 30 are rotated from a folded position to immediately before a fully-open position, as shown in FIGS. 15(A), 15(B), the hinge member 30 and the intermediate member 70 behave in the same manner as in the first embodiment. However, as shown in FIG. 15 (C), when the hinge member 30 reaches the fully-open position, the spherical bodies 80A, 80B are in abutment with the bottom surface 77a since the second engagement recesses 75A, 75B are not formed in this embodiment. Accordingly, no rotational-biasing force acts on the hinge member 30 when the hinge member 30 is in the fully-open position, and the hinge member 30 is held in the fully-open position by the frictional resistance between the spherical bodies 80A, 80B and the bottom surfaces 77a. A position of the intermediate member when the hinge member 30 is in the fully-open position is referred to as a fourth position. The fourth position of the intermediate member 70 is determined by abutment of the second housing 2 against a first housing 1. Alternatively, the fourth position of the intermediate member 70 may be determined by abutment of the spherical bodies 80A, 80B against the end surfaces 77b of the recesses 77.

[0034] When the second housing 2 and the hinge member 30 are rotated from the fully-open position toward the folded position, as shown in FiG. 15(D), the intermediate member 70 is rotated toward the folded position together with the hinge member 30. When the hinge member 30 and the intermediate member 70 are rotated up to a predetermined intermediate position, the spherical bodies 80A, 80B fit in the first engagement recesses 74A, 74B, and thus the intermediate member 70 is stopped by the movable member 50. As a result, only the hinge member 30 is rotated further toward the folded position. When the second housing 2 and the hinge member 30 are rotated up to the folded position, they are held in the folded position by a biasing force of a coiled spring 60.

[00351 FIGS. 16 to 19 show a mobile phone handset B in which a hinge assembly according to a third embodiment of the present invention is used in different rotational positions. As is obvious from FIGS. 16 and 18, in the mobile phone handset B, too, a second housing 2 is rotatable within an angular range of 180 degrees between a folded position and a fully-open position with respect to a first housing 1.

When the second housing 2 is rotated from the folded position toward the fully-open position, the second housing 2 is held in position in a predetermined intermediate position (100 degrees away from the folded position) as shown in FIG. 17 by a predetermined amount of force. This behavior is similar to that of the first embodiment.

However, in the mobile phone handset B, when the second housing 2 is rotated from the fully-open position toward the folded position, the second housing 2 is stopped at a second intermediate position (position 80 degrees away from the folded position toward the fully-open position in this embodiment) as shown in FIG. 19, which is different from the intermediate position, with a predetermined amount of force.

[0036] In order to make the second housing 2 behave in theabove-described manner, an inclination angle a2 is specified to be greater than an inclination angle 2 in this embodiment. The other constructions are the same as those in the first embodiment.

Therefore, the second housing 2 and a hinge member 30 behave in the following manner. That is, when the hinge member 30 is in the folded position, as shown in FIG. 20 (A), an intermediate member 70 is in a first position with respect to the hinge member 30 and in a third position with respect to a movable member 50. Accordingly, the hinge member 30 is biased from the fully-open position toward the folded position by a biasing force of a coiled spring 60 and the hinge member 30 and the second housing 2 are held in the folded position by the biasing force of the coiled spring 60. When the hinge member is rotated from the folded position toward the intermediate position, the intermediate member 70 remains stationary and only the hinge member 30 is rotated toward the fully-open position.

When the hinge member 30 is rotated 100 degrees from the folded position and reaches the second position, as shown in FIG. 20(B), an abutment protrusion 76 is abutted by a second end surface 33b and the hinge member 30 is stopped at the intermediate position with a predetermined amount of force.

[0037] When the hinge member 30 is further rotated from the intermediate position toward the fully-open position, the intermediate member 70 is rotated toward the fully-open position together with the hinge member 30. When the hinge member 30 reaches the fully-open position, the second housing 2 abuts the first housing 1. Thereby the hinge member 30 is prohibited from being rotated further. When the hinge member 30 is stopped in the fully-open position, the intermediate member 70 is in a fourth position and spherical bodies 80A (80B) are abutted by inclined surfaces 75a (75b). Therefore, if, as in the first embodiment, the inclination angle a2 were specified to be smaller than the inclination angle 132, the intermediate member 70 would not be rotated from the fourth position. However, since the inclination angle a2 is specified to be greater than the inclination angle f2 in this embodiment, the intermediate member 70 is rotated in the direction of arrow A in FIG. (A) (direction from the folded position toward the fully-open position) with respect to the hinge member 30 and the movable member 50 by a rotational-biasing force of the coiled spring 60 as converted by the spherical bodies 80A (80B) and the inclined surfaces 75a (75b). To be more specific, the intermediate member 70 is rotated until the spherical body 80A abutted against an inclined surface 75c which is positioned on the opposite side from the inclined surface 75a of a second engagement recess 75A and inclined in the opposite direction from the inclined surface 75a. The rotation angle is specified to be 10 degrees in this embodiment. Consequently, as shown in FIG. 20 (D), when the hinge member 30 is in the fully-open position, the abutment projection 76 is 10 degrees away from the second inclined surface 33b in the direction of arrow A. An angular range (second angular range) in which the intermediate member 70 can be rotated with respect to the movable member 50 is wider than the second angular range in the first embodiment by an angle (10 degrees as mentioned above) through which the intermediate member is rotated from the fourth position until the spherical body 80A is abutted against the inclined surface 75c. The inclined surface 75a is a concave spherical surface having the same radius of curvature as a convex spherical surface constituting the spherical body 80A.

[00381 When the hinge member 30 is rotated from the fully-open position toward the folded position, since the inclination angle a2 is greater than an inclination angle 2, the intermediate member 70 remains stationary, and only the hinge member 30 is rotated toward the folded position. When the hinge member 30 is rotated up to the predetermined second intermediate position as shown in FIG. 20 (E), the hinge member 30 is held in the second intermediate position with a predetermined amount of force by the abutment of the abutment protrusion 76 against a first end surface 33a. To be more specific, the intermediate member 70 is held in position with respect to the movable member 50 with a predetermined amount of force by the abutment of the spherical body 80A against the inclined surfaces 75a, 75c and, at the same time, the hinge member 30 is held in position with respect to the intermediate member 70 with a predetermined amount of force by the abutment of the abutment protrusion 76 against the first end surface 33a and a first inclined bottom surface 33c. The first end surface 33a is arranged such that the abutment protrusion 76 is abutted against the first end surface 33a when the abutment protrusion 76 is moved through a predetermined angle (10 degrees in this embodiment) from a position shown in FIG. 20(A) in a direction from the fully-open position toward the folded position.

Accordingly, when the hinge member 30 is rotated 100 degrees from the fully-open position toward the folded position, the hinge member is held in that position, that is the second intermediate position, with a predetermined amount of force. As is obvious from the foregoing, the intermediate member 70 is rotatable within a range of angle between a position in which the abutment protrusion 76 is abutted against the first end surface 33a and a position in which the abutment protrusion 76 is abutted against the second end surface 33b, and that range of angle is referred to as a first angular range. The first angular range is wider than the first angular range in the first embodiment by 10 degrees.

10039] When the hinge member 30 is further rotated in a direction from the second intermediate position toward the folded position, the intermediate member 70 is rotated together with the hinge member 30. When the hinge member 30 reaches the folded position, the second housing 2 is abutted against the first housing 1, and consequently, the hinge member 30, being unable to be rotated further, is stopped. When the hinge member 30 reaches the folded position, if the spherical body 80A (80B) were fitted in first engagement recess 74A (74B) as in the first embodiment, the intermediate member 70 would not be rotated either and would be stopped together with the hinge member 30. However, in this embodiment, as shown in FIG. 20(F), when the hinge member 30 is rotated in a direction from the fullyopen position toward the folded position and reaches the folded position, the intermediate member 70 is positioned 10 degrees before a position in which the spherical body 80A fits in the first engagement recess 74A, and the spherical body 80A is abutted against an intersecting portion between a bottom surface of the first engagement recess 74A and a second opposing surface 71b. Consequently, the biasing force of the coiled spring 60 is converted into a rotational-biasing force for rotating the intermediate member 70 in a direction from the fullyopen position toward the folded-position. This rotational-biasing force is greater than the rotational-biasing force of the coiled spring 60 converted by the first inclined bottom surface 33c and the abutment protrusion 76.

Consequently, the intermediate member 70 is rotated in the direction from the fully-open position toward the folded position with respect to the hinge member 30 until the spherical body 80A fits in the first engagement recess 74A (10 degrees), that is, until the spherical body 80A moves form a position shown in FIG. 20(F) to a position shown in FIG. 20(G), thereby the intermediate member 70 being returned to the first position.

[0040] FIGS. 21 through 23 respectively show a movable member 50, an intermediate member 70 and a hinge member 30 used in a fourth embodiment of the present invention. As shown in FIG. 21, a pair of protrusions 52A, 52B extending in a radial direction is formed in an opposing surface of the movable member 50 facing the intermediate member 70a. The pair of protrusions 52A, 52B is arranged symmetrically with respect to a rotation axis. In other words, the pair of protrusions 52A, 52B is arranged 180 degrees away from each other in a circumferential direction of the movable member 50. As shown in FIG. 22, a pair of recesses 77A, 77B extending in a circumferential direction is formed in a second opposing surface 71b of the intermediate member 70 facing the movable member 50. The pair of recesses 77A, 77B is arranged 180 degrees away from each other in a circumferential direction of the intermediate member 70.

Similarly, a pair of recesses 78A, 78B extending in the circumferential direction is formed in a first opposing surface 71a of the intermediate member 70 facing the hinge member 30 and arranged 180 degrees away from each other in the circumferential direction. As shown in FIG. 23, a pair of protrusions 34A, 34B extending in a radial direction is formed in an opposing surface of the hinge member 30 facing the intermediate member 70. The pair of protrusions 34A, 34B is arranged 180 degrees away from each other in a circumferential direction of the hinge member 30.

[0041] As shown in FIG.24, by a biasing force of a coiled spring 60 (see the description in the first embodiment), the movable member 50 is abutted against the second opposing surface 71b of the intermediate member 70 and the first opposing surface 71a of the intermediate member 70 is abutted against the hinge member 30. At the same time, the protrusions 52A, 52B of the movable member 50 are respectively inserted in the recesses 77A, 77B of the intermediate member 70 such that the protrusions 52A, 52B are movable in the circumferential direction, and the protrusions 34A, 34B of the second hinge member 30 are respectively inserted in the recesses 78A, 78B of the intermediate member 70 such that the protrusions 34A, 34B are movable in the circumferential direction. Accordingly, the intermediate member 70 is rotatable with respect to the hinge member 30 within a first angular range between a position in which the protrusions 34A, 34B are respectively abutted against one end surfaces in circumferential directions of the recesses 78A, 78B and a position in which the protrusions 34A, 34B are respectively abutted against the other end surfaces in circumferential directions of the recesses 78A, 78B. With respect to the movable member 50, the intermediate member 70 is rotatable within a second angular range between a position in which the protrusions 52A, 52B are respectively abutted against one end surfaces in circumferential directions of the recesses 77A, 77B and a position in which the protrusions 52A, 52B are respectively abutted against the other end surfaces in circumferentiall directions of the recesses 77A, 77B.

[0042] When the hinge member 30 is in a folded position, as shown in FIG. 24(A), the protrusions 34A, 34B are abutted against the one end surfaces in the circumferential directions of the recesses 78A, 78B and the protrusions 52A, 52B are abutted against the other end surfaces in the circumferential directions of the recesses 77A, 77B.

When the hinge member 30 is in a fully-open position, as shown in FIG. 24(B), the protrusions 34A, 34B are abutted against the other end surfaces of the recesses 78A, 78B and the protrusions 52A, 52B are abutted against the one end surfaces of the recesses 77A, 77B.

As is obvious from the foregoing, in this embodiment, when the hinge member 30 is in the folded position and in the fully-open position, a position of the intermediate member 70 with respect to the hinge member 30 and a position of the intermediate member 70 with respect to the movable member 50 are specified. However, when the hinge member 30 is in a position other than the folded position and the fully-open position, the position of the intermediate member 70 with respect to the hinge member 30 and the position of the intermediate member 70 with respect to the movable member 50 are not specified but determined by a relationship between a magnitude of a frictional fcsistance between the hinge member 30 and the intermediate member 70 and a magnitude of a frictional resistance between the movable member 50 and the intermediate member 70. Of course, if the relationship between the magnitude of the frictional resistance between the hinge member 30 and the intermediate member 70 and the magnitude of the frictional resistance between the movable member 50 and the intermediate member 70 is kept constant, the position of the intermediate member 70 with respect to the hinge member 30 and the position of the intermediate member 70 with respect to the movable member 50 can be specified.

[0043] FIGS. 25 and 26 show a mobile phone handset C in which a hinge assembly according to a second aspect of the present invention is used. The mobile phone handset C also includes a first housing 1 and a second housing 2. The first housing 1 and the second housing 2 are connected to each other by a hinge unit 100 including the hinge assembly of this invention such that the first housing 1 and the second housing 2 are rotatable about first and second rotation axes Li, L2 (see FiG. 29(A)) parallel to each other. Assuming that the first housing 1 is fixed in position, the second housing 2 is rotatable with respect to the first housing 1 between a folded position in which a front surface 2a is abutted against a front surface la of the first housing 1 and a fully-open position in which the second housing 2 is rotated almost 360 degrees from the folded position and a rear surface 2b is abutted against a rear surface id of the first housing 1.

The second housing 2 is held in an extended position shown in FIG. 25, in which the second housing 2 is rotated 180 degrees from the folded position, with a predetermined amount of force.

[0044] In the mobile phone handset C, the first housing 1 is also composed of two half bodies 1A, lB and a recess le opposing a recess 2c of the second housing 2 is formed in one end portion of the first housing 1. The hinge unit 100 is accommodated in a space defined by the recess ie and the recess 2c of the second housing 2.

[0045] As shown in FIGS. 26 through 30, the hinge unit 100 comprises a bottomed cylindrical hinge case 101 having an elliptical cross-section, two hinges 3, 3 and a hinge assembly 200 according to the present invention. The two hinges 3, 3 are arranged parallel with each other and as shown in FIG. 29(D), circular shaft parts 3a, 3a of the hinges 3, 3 are rotatably fitted to a bottom part 102 of the hinge case 101 (only one of the hinges 3 is shown in FIG. 29(D)). An angular shaft part 3b of one of the hinges 3 is non-rotatably connected to that one side portion of the first housing 1 which is adjacent to the recess le. An angular shaft part 3b of the other hinge 3 is non-rotatably connected to that one side portion of the second housing 2 which is adjacent to the recess 2c. Consequently, the one side portion of the first housing 1 is connected to the hinge case 101 such that the first housing 1 is rotatable about the first rotation axis Li via one of the hinges 3 and the one side portion of the second housing 2 is connected to the hinge case 101 such that the second housing 2 is rotatable about the second rotation axis L2 via the other of the hinges 3.

Loo461 The hinge assembly 200 includes a hinge cylinder (assembly main body) 210 and a pair of attachment members 280A, 280B rotatably supported by the hinge cylinder 210. The hinge cylinder 210 is nonrotatably inserted into the hinge case 101. One end portion of the attachment member 280A is supported by the hinge cylinder 210 such that the attachment member 280A is rotatable about the first rotation axis LI. The other end portion of the attachment member 280A is non-rotatably connected to the other side portion of the first housing 1 adjacent to the recess le. One end portion of the attachment member 280B is supported by the hinge cylinder 210 such that the attachment member 280B is rotatable about the second rotation axis L2. The other end portion of the attachment member 280B is non-rotatably connected to the other side portion of the second housing 2 adjacent to the recess 2c.

Accordingly, the other side portion of the first housing 1 is connected to the hinge case 101 through the hinge assembly 200 such that the first housing 1 is rotatable about the first rotation axis Li and the other side portion of the second housing 2 is connected to the hinge case 101 through the hinge assembly 200 such that the second housing 2 is rotatable about the second rotation axis L2. In this manner, the first housing 1 and the second housing 2 are connected to each other through the hinge unit 100 such that the first housing 1 and the second housing 2 are rotatable about the first and second rotation axes Li, L2.

[00471 To be more specific, as shown in FIGS 28 through 30, the hinge assembly 200 includes a reinforcement board 220, first and second hinge members 230A, 230B, first and second hinge pins 24OA, 240B, movable members (first and second movable members) 250, first and second coiled springs (biasing means) 260A, 260B and first and second intermediate members 270A, 270B as well as the hinge cylinder 210 and the pair of attachment members 280A, 280B.

[0048] As shown in FIGS. 29(D) and 30, the hinge cylinder 210 includes a cylinder main body 211 and a lid body 212. The cylinder main body 211 is in a shape of a bottomed cylinder having an elliptical cross-section. The cylinder main body 211 is non-rotatably inserted into the hinge case 101 as far as a bottom part 211a of the cylinder main body 211 is abutted against a bottom part 102 of the hinge case 101 via the reinforcement member 220. The lid body 212 is fixedly fitted into an opening side end portion of the cylinder main body 211. In place of the hinge cylinder 210, two assembly main bodies similar to the assembly main body 20 of the first embodiment may be used, with both of the assembly main bodies non-rotatably inserted in the hinge case 101.

[0049] The first and second hinge pins 240A, 240B are arranged with their axes respectively aligned with the first and second rotation axes Li, L2. The first and second hinge pins 240A, 240B rotatably pass through the reinforcement board 220 and the bottom part 2lia of the hinge cylinder 210. A head part 241 is formed in one end part of each of the first and second hinge pins 240A, 240B. Abutment of this head part 241 against the bottom part 211a via the reinforcement board 220 prohibits the movement of the first and second hinge pins 240A, 240B in a direction from the bottom part 2ila toward the opening portion of the cylinder main body 2 11. The other end part of each of the hinge pins 240A, 240B projects out of the hinge cylinder 210 passing through the lid body 212.

[00501 The movable member 250 is fitted inside the hinge cylinder 2 10 such that the movable member 250 is non-rotatable but movable in a direction of the first and second rotation axes Li, L2. The first and second hinge pins 240A, 240B pass through the movable member 250 such that the first and second hinge pins 240A, 240B are rotatable and movable in the direction of the rotation axes Li, L2. The first and second coiled springs 260A, 260B are arranged between the movable member 250 and the bottom part 211a. The movable member 250 is biased toward the opening portion of the hinge cylinder 210 by the coiled springs 260A, 260B. Alternatively, the movable member 250 may be constituted by two independent members, respectively referred to as the first and second movable members, which are fitted in the hinge cylinder 210 such that they are non-rotatable but movable in the direction of the first and second rotation axes Li, L2 respectively. In that case, the first and the second movable members are respectively biased by the coiled springs 260A, 260B. Conversely, when the first and the second rotatable members are formed integrally as one member as in this embodiment, a single coiled spring may be used in place of the first and second coiled springs 260A, 260B.

[00511 The first and second intermediate members 270A, 270B and the first and second hinge members 230A, 230B are inserted inside the hinge cylinder 210 between the movable member 250 and the lid body 212 in that order from the movable member 250 side to the lid body 212 side. The first hinge member 230A and the first intermediate member 270A are arranged in the hinge cylinder 210 such that the first hinge member 230A and the first intermediate member 270A are rotatable about the first rotation axis Li and movable in the direction of the first rotation axis Li. The first hinge pin 240A rotatably and movably passes through the first hinge member 230A and the first intermediate member 270A. The second hinge member 230B and the second intermediate member 270B are arranged in the hinge cylinder 210 such that the second hinge member 230B and the second intermediate member 270B are rotatable about the second rotation axis L2 and movable in the direction of the second rotation axis L2. The second hinge pin 240B rotatably and movably passes through the second hinge member 230B and the second intermediate member 270B. The first and second hinge members 230A, 230B are rotatably supported by the lid body 212, in other words, rotatably supported by the hinge cylinder 210.

[00521 The attachment members 280A, 280B are respectively fixed to the end parts of the first and second hinge pins 240A, 240B projecting out of the lid body 212. The first and second hinge members 230A, 230B are respectively abutted against the attachment members 280A, 280B. To be more specific, the movable member 250 is abutted against the first and second intermediate members 270A, 270B by the coiled springs 260A, 260B, and consequently, the first and second intermediate members 270A, 270B are abutted against the first and second hinge members 230A, 230B, respectively, and then the first and second hinge members 230A, 230B are abutted against the attachment members 280A, 280B, respectively. At the same time, abutment of the head parts 241 against the bottom part 211a via the reinforcement board 220 prohibits the hinge pins 240A, 240B from moving in a direction in which the first and second coiled springs 260A, 260B bias the movable member 250, the first and second intermediate members 270A, 270B and the first and second hinge members 230A, 230B. Accordingly, the hinge cylinder 210, reinforcement member 220, the first and second hinge members 230A, 230B, the first and second hinge pins 240A, 240B, the movable member 250, the first and second coiled springs 260A, 260B, the first and second intermediate members 270A, 270B and the attachment members 280A, 280B are unitized into a single assembly.

[0053] The first and second hinge members 230A, 230B are non-rotatably connected to the attachment members 280A, 280B, respectively. Accordingly, when the second housing 2 is rotated with respect to the first housing 1, the first and the second hinge members 230A, 230B are rotated. To be more specific, the first and second hinge members 230A, 230B are rotated by the same angle in the opposite direction by meshing of a first and second gear parts (first and second gears) 231A, 231B with each other. The first and second gear parts 231A, 231B are integrally formed on the first and second hinge members 230A, 230B respectively A rotation angle of the first and second hinge members 230A, 230B is the half of a rotation angle of the second housing 2. The first and second gear parts 231A, 231B may be formed separately from the first and second hinge members 230A, 230B and non-rotatably connected to the first and second hinge members 230A, 230B respectively.

[00541 By the action of the hinge assembly 200, the second housing 2 is held in the folded position when in the folded position, being rotationally biased in a direction from the fully-open position toward the folded position, and is held in the fully-open position when in the fully-open position, being rotationally biased in a direction from the folded position toward the fully-open position, and is stopped at the extended position with a predetermined amount of force when in the extended position in which the second housing 2 is rotated 180 degrees from the folded position 10055] To be more specific, a pair of spherical bodies 290A, 290B is arranged on an opposing surface of the movable member 250 facing the first intermediate member 270A. The spherical bodies 290A, 290B are arranged on a circumference about the first rotation axis Li degrees away from each other in a circumferential direction. On the other hand, a pair of first engagement recesses 271A, 271B (see Fig. 29(D)) and a pair of second engagement recesses (not shown) are formed in an opposing surface of the intermediate member 270A facing the movable member 250. The shapes of the pair of first engagement recesses 271A, 271B and the pair of second engagement recesses are similar to those of the first engagement recesses 74A, 74B and the second engagement recesses 75A, 75B of the first embodiment, respectively. Moreover, the first engagement recesses 271, 271B and the second engagement recesses are arranged such that the spherical bodies 290A, 290B respectively fit in the first engagement recesses 271A, 271B when the first intermediate member 270A is in a third position with respect to the movable member 250 and that the spherical bodies 290A, 290B are respectively abutted against inclined surfaces of the second engagement recesses corresponding to the inclined surfaces 75a, 75b of the second engagement recesses 75A, 75B of the first embodiment when the intermediate member 270A is in a fourth position with respect to the movable member 250. However, while the angle between the third position and the fourth position, i.e. the second angular range, of the intermediate member 70A is 80 degrees in the first embodiment, a second angular range of the intermediate member 270A is specified to be 90 degrees in this embodiment. Similarly, a pair of spherical bodies 290A, 290B is provided in an opposing surface of the movable member 250 facing the second intermediate member 270B and a pair of first engagement recesses (not shown) and a pair of second engagement recesses (not shown) are formed in an opposing surface of the second intermediate member 270B facing the movable member 250.

10056] Three abutment protrusions 272 are formed in an opposing surface of the first intermediate member 270A facing the ftrst hinge member 230A. The abutment protrusions 272 are arranged in a circumferential direction equally spaced apart from each other in the similar manner to the abutment protrusions 76 of the first embodiment. Three abutment recesses (not shown) are formed in an opposing surface of the first hinge member 230A facing the first intermediate member 270A. Relationship between these abutment recesses and the abutment protrusions 272 is similar to the relationship between the abutment recesses 33 and the abutment protrusions 76 of the first embodiment except that while in the first embodiment, the angle between the first position and the third position of the intermediate member 70 with respect to the second hinge member 30 is 100 degrees, a corresponding angle is specified to be 90 degrees in this embodiment. Similarly, three abutment protrusions 272 are formed in an opposing surface of the second intermediate member 270B facing the second hinge member 230B and three abutment recesses (not shown) are formed in an opposing surface of the second hinge member 230B facing the second intermediate member 270B. The abutment recesses of the second hinge member 230B and the abutment protrusions 272 of the second intermediate member 270B are similar to the abutment recesses of the first hinge member 230A and the abutment protrusions 272 of the first intermediate member 270A, respectively, except that the abutment recesses of the second hinge member 230B and the abutment protrusions 272 of the second intermediate member270B are arranged symmetrically with the abutment recesses of the first hinge member 230A and the abutment protrusions 272 of the first intermediate member 270A to support the feature that the first hinge member 230A and the second hinge member 230B are rotated in the opposite directions. Accordingly, in this embodiment, the first and second angular ranges of the first intermediate member 270A are respectively the same as the third and fourth angular ranges of the second intermediate member 270B. However, these angular ranges do not have to be the same.

[0057] When the second housing 2 and the first and second hinge members 230A, 230B are in the folded position, the second housing 2 and the first and second hinge members 230A, 230B are held in the folded position by rotational-biasing forces of the first and second coiled springs 260A, 260B converted by first conversion mechanisms respectively provided between the first hinge member 230A and the first intermediate member 270A and between the second hinge member 230B and the second intermediate member 270B. When the second housing 2 and the first and second hinge members 230A, 230B are in the fully-open position, the second housing 2 and the first and second hinge members 230A, 230B are held in the fully-open position by rotational-biasing forces of the first and second coiled springs 260A, 260B converted by second conversion mechanisms respectively provided between the movable member 250 and the first intermediate member 270A and between the movable member 250 and the second intermediate member 270B. When the second housing 2 and the first and second hinge members 230A, 230B are in the extended position, the second housing 2 and the first and second hinge members 230A, 230B are held in the extended position with a predetermined amount of force.

[00581 The spherical bodies 290A, 290B, the first engagement recesses 271A, 271B, the second engagement recesses, the abutment protrusions 272 and the abutment recesses do not have to be provided both among the movable member 250, the first intermediate member 270A and the first hinge member 230A and among the movable member 250, the second intermediate member 270B and the second hinge member 230B, but may be provided in one of the locations given above.

[0059] The present invention is not restricted to the above described embodiments and various modifications are possible within the scope of the present invention.

For example, while in the hinge assembly 10 given above, the pair of spherical bodies 80A, 80B is provided on the movable member and the pair of first engagement recesses 74A, 74B and the pair of second engagement recesses 75A, 75B are formed in the intermediate member 70, alternatively, a pair of first engagement recesses and a pair of second engagement recesses may be formed in the movable member 50 with a pair of spherical bodies (projections) provided on the intermediate member. Similarly, abutment protrusions may be formed in the hinge member 30 with abutment recesses formed in the intermediate member 70. Moreover, a pair of spherical bodies (projections) may be provided on either one of the hinge member 30 and the intermediate member 70, with a pair of first engagement recesses and a pair of second engagement recesses provided on the other. Abutment protrusions may be provided on either one of the movable member 50 and the intermediate member 70 with abutment recesses provided on the other. Such modifications may be applied to the hinge assembly 200, too.

INDUSTRIAL APPLICABILITY

[00601 A hinge assembly according to the present invention can be utilized as a hinge assembly for rotatably connecting two members of a portable device such as a transmission section and a reception section of a mobile phone handset.

Claims

CLAIMS

1. A hinge assembly comprising: a hinge member; a movable member connected to said hinge member such that said movable member is rotatable about a rotation axis and movable to and from said hinge member in a direction of said rotation axis; and biasing means biasing said movable member toward said hinge member, characterized in that an intermediate member is provided between said hinge member and said movable member such that said intermediate member is rotatable about said rotation axis and movable in the direction of said rotation axis, said movable member is abutted against said intermediate member by a biasing force of said biasing means, said intermediate member is abutted against said hinge member by the biasing force of said biasing means, said intermediate member is rotatable within a predetermined first angular range with respect to said hinge member, and said intermediate member is rotatable within a predetermined second angular range with respect to said movable member.

2. A hinge assembly according to claim 1, wherein a first conversion mechanism is provided at least one of between said hinge member and said intermediate member and between said movable member and said intermediate member, said first conversion mechanism converting the biasing force of said biasing means into a rotational-biasing force for rotationally biasing said hinge member in a direction from one end toward the other end within the first angular range when said intermediate member is in one end portion within the first angular range with respect to said hinge member and in one end portion within the second angular range with respect to said movable member.

3. A hinge assembly according to claim 1 or 2, wherein a second conversion mechanism is provided at least the other of between said hinge member and said intermediate member and between said movable member and said intermediate member, said second conversion mechanism converting the biasing force of said biasing means into a rotational-biasing force for rotationally biasing said hinge member in a direction from the other end toward one end within the first angular range when said intermediate member is in the other end portion within the first angular range with respect to said hinge member and in the other end portion within the second angular range with respect to said movable member.

4. A hinge assembly comprising: a first hinge member arranged on a first rotation axis; a second hinge member arranged on a second rotation axis parallel to said first rotation axis; a first movable member connected to said first hinge member such that said first movable member is rotatable about the first rotation axis and movable to and from said first hinge member in a direction of the first rotation axis; a second movable member connected to said second hinge member such that said second movable member is rotatable about the second rotation axis and movable to and from said second hinge member in a direction of the second rotation axis; a first intermediate member provided between said first hinge member and said first movable member such that said first intermediate member is rotatable about the first rotation axis and movable in the direction of the first rotation axis; a second intermediate member provided between said second hinge member and said second movable member such that said second intermediate member is rotatable about the second rotation axis and movable in the direction of the second rotation axis; biasing means biasing said first and second movable members toward said first and second hinge members respectively, thereby bringing said first and second movable members into abutment with said first and second intermediate members respectively and bringing said first and second intermediate members into abutment with said first and second hinge members respectively; a first gear non-rotatably provided on said first hinge member; and a second gear non-rotatably provided on said second hinge member and meshing with said first gear, characterized in that said first intermediate member is rotatable within a predetermined first angular range with respect to said first hinge member and rotatable within a predetermined second angular range with respect to said first movable member, and said second intermediate member is rotatable within a predetermined third angular range with respect to said second hinge member and rotatable within a predetermined fourth angular range with respect to said second movable member.

5. A hinge assembly according to claim 4, wherein said hinge assembly further comprises an assembly main body rotatably supporting said first and second rotatable members.

6. A hinge assembly according to claim 5, wherein said assembly main body is formed in a circular cylindrical configuration and said first and second hinge members on which said first and second gears are respectively provided, said first and second intermediate members, said first and second movable members and said biasing means are received in said hinge member.

7. A hinge assembly according to any one of claims 4 to 6, wherein a first conversion mechanism is provided in one or more of the following locations: between said first hinge member and said first intermediate member, between said first intermediate member and said first movable member, between said second hinge member and said second intermediate member and between said second intermediate member and said second movable member, said first conversion mechanism converting the biasing force of said biasing means into a rotational-biasing force for rotationally biasing said first hinge member in a direction from one end toward the other end within the first angular range or into a rotational-biasing force for rotationally biasing said second hinge member in a direction from one end toward the other end within the third angular range when said first intermediate member is in one end portions within the first and second angular ranges and said second intermediate member is in one end portions within the third and fourth angular ranges.

8. A hinge assembly according to any one of claims 4 to 7, wherein a second conversion mechanism is provided in one or more of the following locations: between said first hinge member and said first intermediate member, between said first intermediate member and said movable member, between said second hinge member and said second intermediate member and between said second intermediate member and said second movable member, said second conversion mechanism converting the biasing force of said biasing means into a rotational-biasing force for rotationally biasing said first hinge member in a direction from the other end toward one end within the first angular range or into a rotational-biasing force for rotationally biasing said second hinge member in a direction from the other end toward one end within the third angular range when said first intermediate member is in the other end portions within the first and second angular ranges and said second intermediate member is in the other end portions within the third and fourth angular ranges.