WO2010091552A1

WO2010091552A1 - Paper-retaining mechanism

Info

Publication number: WO2010091552A1
Application number: PCT/CN2009/070420
Authority: WO
Inventors: Hung Yu Cheng
Original assignee: World Wide Stationery Manufacturing Company Limited
Priority date: 2009-02-13
Filing date: 2009-02-13
Publication date: 2010-08-19
Also published as: TW201029858A; CN102083634B; CN102083634A

Abstract

A paper-retaining mechanism (100, 200, 300, 400) comprises a base (104, 204, 304, 404), at least two post members (102, 202) secured to said base, a pair of arch members (106, 206) joined with each other for simultaneous movement, wherein the arch members are movable relative to the post members between a closed position in which the arch members are in contact with the post members to form two closed rings and an open position in which the arch members are out of contact with the post members to open the rings; and a lever assembly operable to move the arch members between the closed position and the open position. The lever assembly includes a lever member (124, 224, 324, 424), a clutch assembly (120, 122; 220 222) and a rotatable member (118, 218, 318, 418). The lever member has a slot (152, 252, 352, 452). The clutch assembly is engaged with the lever member by engagement means (150, 154; 250, 254) at least partly received through the slot of said lever member. The engagement means is slidably movable within and relative to the slot during operation of the lever assembly.

Description

Paper-Retaining Mechanism

This invention relates to a paper-retaining mechanism and a paper-retaining device incorporating such a paper-retaining mechanism.

Various paper-retaining mechanisms have been available. In one type of such conventional paper- retaining mechanisms generally called lever-arch type file mechanisms, a one-armed lever is pivotable to pivot a pair of arches relative to a pair of fixed posts to allow pieces of hole-punched paper to be retrieved from or inserted into the file mechanism, and for closing the posts and arches to form a pair of closed rings to retain the paper therein. The pair of arches are joined by an intervening crank on which a roller attached to the lever travels during pivotal movement of the lever, to effect opening or closing of the pair of rings. In operating such a conventional file mechanism, the lever is pivoted downwardly to close the ring pairs formed by the posts and arches and is pivoted upwardly to allow a spring leaf to pivot the arches away from the posts, to thereby open the rings.

A problem associated with such a conventional paper- retain ing mechanism is that the lever, when in its upper position, is very close and sometimes even touches an arch. This means that pieces of hole-punched paper can only be inserted into or retrieved from the posts, but not the arches. This renders the use of the mechanism inconvenient. On the other hand, if the lever is made to be less inclined to the base to which the posts are fixed, there is not sufficient pivotable movement to bring about opening of the arches.

It is thus an object of the present invention to provide a paper-retaining mechanism and a paper-retaining device, such as a document file or writing board, incorporating such a paper- retaining mechanism in which the aforesaid shortcoming is mitigated, or at least to provide a useful alternative to the public.

According to a first aspect of the present invention, there is provided a paper-retaining mechanism including a base, at least two post members secured to said base, a pair of arch members joined with each other for simultaneous movement, wherein said arch members are movable relative to said post members between a closed position in which said arch members are in contact with said post members to form two closed rings and an open position in which said arch members are out of contact with said post members to open said rings, and a lever assembly operable to move said arch members between said closed position and said open position, wherein said lever assembly includes a lever member, a clutch assembly, and a rotatable member; characterized in that said lever member has a slot, that said clutch assembly is engaged with said lever member by engagement means at least partly received through said slot of said lever member, and that said engagement means is slidably movable within and relative to said slot during operation of said lever assembly.

According to a second aspect of the present invention, there is provided a paper-retaining device including a substrate engaged with a paper-retaining mechanism, said paper-retaining mechanism including a base, at least two post members secured to said base, a pair of arch members joined with each other for simultaneous movement, wherein said arch members are movable relative to said post members between a closed position in which said arch members are in contact with said post members to form two closed rings and an open position in which said arch members are out of contact with said post members to open said rings, and a lever assembly operable to move said arch members between said closed position and said open position, wherein said lever assembly includes a lever member, a clutch assembly, and a rotatable member; characterized in that said lever member has a slot, that said clutch assembly is engaged with said lever member by engagement means at least partly received through said slot of said lever member, and that said engagement means is slidably movable within and relative to said slot during operation of said lever assembly.

Embodiments of the present invention will now be described, by way of examples only, with reference to the accompanying drawings, in which: Fig. 1 is an exploded view of a lever-arch type file mechanism according to a first embodiment of the present invention;

Fig. 2 is a front perspective view of the mechanism of Fig. 1 in a ring-closed configuration; Fig. 3 is a front perspective view of the mechanism of Fig. 2 in a ring-open configuration and with the lever in a lower position;

Fig. 4 is a front perspective view of the mechanism of Fig. 2 in the ring-open configuration and with the lever in an upper position; Fig. 5 is a front perspective view of the mechanism of Fig. 2 in the ring-closed configuration and with the lever in a lower position;

Fig. 6 is a front perspective view of the mechanism of Fig. 5;

Fig. 7 is a rear perspective view of the mechanism of Fig. 6;

Fig. 8 is a rear view of the mechanism of Fig. 6; Fig. 9 is a side view of the mechanism of Fig. 8;

Fig. 10 is a front view of the mechanism of Fig. 8;

Fig. 11 is a top view of the mechanism of Fig. 10;

Fig. 12 is a right side view of the mechanism of Fig. 10;

Fig. 13 is a left side view of the mechanism of Fig. 10; Fig. 14 is an exploded view of a lever-arch type file mechanism according to a second embodiment of the present invention;

Fig. 15 is a front perspective view of the mechanism of Fig. 14 in a ring-closed configuration;

Fig. 16 is a front perspective view of the mechanism of Fig. 15 in a ring-open configuration and with the lever in a lower position;

Fig. 17 is a front perspective view of the mechanism of Fig. 15 in the ring-open configuration and with the lever in an upper position;

Fig. 18 is a front perspective view of the mechanism of Fig. 15 in the ring-closed configuration and with the lever in a lower position; Fig. 19 is a front perspective view of the mechanism of Fig. 15 in a ring-closed configuration;

Fig. 20 is a rear perspective view of the mechanism of Fig. 19;

Fig. 21 is a front view of the mechanism of Fig. 19;

Fig. 22 is a top view of the mechanism of Fig. 21 ; Fig. 23 is a right side view of the mechanism of Fig. 21 ;

Fig. 24 is a left side view of the mechanism of Fig. 21 ;

Fig. 25 is a rear view of the mechanism of Fig. 21 ;

Fig. 26 is a left side view of the mechanism of Fig. 25; Fig. 27 is a front perspective view of the mechanism of Fig. 15 in a ring-open configuration;

Fig. 28 is a rear perspective view of the mechanism of Fig. 27;

Fig. 29 is a front view of the mechanism of Fig. 27; Fig. 30 is a top view of the mechanism of Fig. 29;

Fig. 31 is a right side view of the mechanism of Fig. 29;

Fig. 32 is a left side view of the mechanism of Fig. 29;

Fig. 33 is a front view of a claw wheel of the clutch assembly of the mechanism shown in Fig. 14; Fig. 34 is a side view of the claw wheel of Fig. 33;

Fig. 35 is a top view of the claw wheel of Fig. 33;

Fig. 36 is a rear perspective view of the claw wheel of Fig. 33;

Fig. 37 is a front view of a lever of the mechanism shown in Fig. 14 with exemplary dimensions and angles; Fig. 38 is a left side view of the lever of Fig. 37;

Fig. 39 is a top view the lever of Fig. 37;

Fig. 40 is a perspective view of the lever of Fig. 37;

Fig. 41 is an exploded view of a lever-arch type file mechanism according to a third embodiment of the present invention; Fig. 42 is a front view of the mechanism of Fig. 41 in a ring-closed configuration;

Fig. 43 is a top view of the mechanism of Fig. 42;

Fig. 44 is a right side view of the mechanism of Fig. 42;

Fig. 45 is a left side view of the mechanism of Fig. 42;

Fig. 46 is a front perspective view of the mechanism of Fig. 42; Fig. 47 is a rear perspective view of the mechanism of Fig. 46;

Fig. 48 is a rear view of the mechanism of Fig. 42;

Fig. 49 is a left side view of the mechanism of Fig. 48;

Fig. 50 is a front view of the mechanism of Fig. 41 in a ring-open configuration;

Fig. 51 is a top view of the mechanism of Fig. 50; Fig. 52 is a left side view of the mechanism of Fig. 50;

Fig. 53 is a front perspective view of the mechanism of Fig. 50;

Fig. 54 is a rear perspective view of the mechanism of Fig. 50;

Fig. 55 is an exploded view of a lever-arch type file mechanism according to a fourth embodiment of the present invention;

Fig. 56 is a front view of the mechanism of Fig. 55 in a ring-closed configuration; Fig. 57 is a top view of the mechanism of Fig. 56; Fig. 58 is a right side view of the mechanism of Fig. 56; Fig. 59 is a left side view of the mechanism of Fig. 56;

Fig. 60 is a front perspective view of the mechanism of Fig. 56; Fig. 61 is a rear perspective view of the mechanism of Fig. 56; Fig. 62 is a rear view of the mechanism of Fig. 56; Fig. 63 is a left side view of the mechanism of Fig. 62; Fig. 64 is a front view of the mechanism of Fig. 56 in a ring-open configuration; Fig. 65 is a left side view of the mechanism of Fig. 64; Fig. 66 is a front perspective view of the mechanism of Fig. 64; and Fig. 67 is a rear perspective view of the mechanism of Fig. 66.

Various components forming a lever-arch type file mechanism according to a first embodiment of the present invention are shown in Fig. 1 , which mechanism being generally designated as 100.

Two posts 102 are fixedly secured to a base 104 so that the posts extend generally vertically from the base 104. Two arches 106 are integrally formed and joined each other via a bent rod 108, such that the arches 106 and the rod 108 are simultaneously movable with one another. The arches 106 are engaged with the base 104 by two clamps 110 integrally formed with the base 104. By way of such an arrangement, the arches 106 are pivotable relative to the base 104 and the posts 102 between a first position ("ring-closed position") in which free ends 106a of the arches 106 contact and are in a mating relationship with free ends 102a of the posts

102 so as to form two closed rings for retaining pieces of hole-punched paper, and a second position ("ring-open position") in which the free ends 106a of the arches 106 are out of contact with the free ends 102a of the posts 102 so as to open the rings to allow pieces of hole-punched paper to be received into or retrieved from the posts

102 or the arches 106. A leaf spring 111 is engaged with the base 104. The spring

111 acts on the bent rod 108 from below and biases the arches 106 towards the ring-open position. A plate 112 integrally formed with the base 104 extends upwardly from the base 104. The plate 112 includes a hole 114 for receiving a first rivet 116 for engaging a plastic wheel 118, a metal claw wheel 120, a perforated plate 122, and a lever 124 to the plate 112. The wheel 118 has four equi-angularly disposed protruding parts 118a with four intervening recessed portions 118b. A second rivet 126 is also received within the hole 114 for engaging a spring 128 to the plate 112.

More particularly, the first rivet 116 is received through a central through hole 130 of the wheel 118, a central through hole 132 of the claw wheel 120, a hole 134 of the perforated plate 122 and a curved slot 136 of the lever 124. Such an arrangement allows the wheel 118, claw wheel 120 and the perforated plate 122 to rotate relative to the plate 112 about a common longitudinal axis A-A fixed relative to the base 104.

The plate 112 has a hole 138 adjacent the base 104 and the lever 124 has a hole 139. These two holes 138, 139 are aligned with each other and through which a rivet 140 and a ring 142 are received for engaging the lever 124 to the plate 112 for relative pivotal movement. By way of such an arrangement, the lever 124 is pivotable relative to the plate 112 about a common longitudinal axis C-C fixed relative to the base 104. The lever 124 is covered at one longitudinal end 124b by a cover 124a which may be made of a soft material, e.g. rubber, for providing more comfort in use.

A first longitudinal end 128a of the spring 128 is engaged with a bent portion 144 of the lever 124 and a second longitudinal end 128b of the spring 128 is fixedly engaged with the plate 112. By way of such an arrangement, the longitudinal end 124b of the lever 124 is biased by the spring 128 away from the base 104.

The perforated plate 122 has a number of generally rectangular holes 146 along its circumferential edge and a generally circular hole 148 at a slightly protruding portion of the plate 122. A rivet 150 is received through a slot 152 of the lever 124 for engagement with a ring 154 and with the hole 148 of the plate 122. By way of such an arrangement, the hole 148 of the plate 122 will move simultaneously with the rivet 150. The slot 152 is of a width allowing the rivet 150 to move within, and thus relative to the lever 124. The lever 124 also has a platelet 156 along an edge of the slot 152. The function of the platelet 156 will be discussed below.

Turning now to Figs. 2 to 5, such show a cycle of operation of the mechanism 100. Taking Fig. 2 as the starting step, such shows the mechanism 100 in a ring-closed configuration and in which the lever 124 is in its stable upper position. A user may then press the lever 124 downwardly (as indicated by the arrow G in Fig. 2) to the position as shown in Fig. 3. This will bring about rotational movement of the wheel 118 in the same direction by 45° to a position in which a recessed portion 118b of the wheel 118 faces directly the bent rod 108. In this position, the leaf spring 111 is allowed to pivot upwardly to pivot the arches 106 away from the posts 102, thus opening the rings.

When the downward pressing force on the lever 124 is released, the lever 124 is returned to its stable upper position by the upward biasing force of the end 128a of the spring 128. During this upward return movement of the lever 124, because of the clutch assembly (to be further discussed below), the wheel 118 will remain stationary, as shown in Fig. 4. If a user then presses the lever 124 downwardly once more, the downward pivotal movement of the lever 124 will bring about rotational movement of the wheel 118 in the same direction by a further 45° to a position in which the bent rod 108 is forced, by a protruding portion 118a of the wheel 118, back to its lower position, against the upward biasing force of the leaf spring 111 , as shown in Fig. 5. When the downward pressing force on the lever 124 is released, the lever 124 will return (upon the upward biasing force of the spring 128) back to its stable upper position, while the wheel 118 remains stationary, as shown in Fig. 2.

Returning to Fig. 1 , the claw wheel 120 has four claws 120a extending towards and engaged with the wheel 118 so that, when the lever assembly is duly assembled, the claw wheel 120 will rotate simultaneously with the wheel 118. The claw wheel 120 has another four resilient claws 120b extending towards the perforated plate 122. Each of these resilient claws 120b is received within a respective hole 146 of the plate 122. The shapes of the claws 120b and holes 146 are such that in downwardly pivotal movement of the lever 124, the holes 146 will engage with the claws 120b for simultaneous movement, thus bringing the wheel 118 into rotational movement in the same direction. On the other hand, during upward pivotal movement of the lever 124, the holes 146 will slip over the claws 120b (thanks to the resilience of the claws 120b and the shape of the holes 156), so that the claw wheel 120 and the wheel 118 will remain stationary. The claw wheel 120 and the perforated plate 122 thus act as a clutch assembly.

An important feature of the mechanism 100 is the provision of the slots 152, 136 in the lever 124. In the mechanism 100, in order to ensure that the lever 124, in its stable upper position, does not extend too close to the arches 106, the lever 124 is inclined relative to the base 104 by about 20°. This means that the maximum angle through which the lever 124 can pivot downwardly to complete the ring-closing/ring-opening action is around 20°. However, as discussed above, the wheel 118 has to rotate by 45° each time. An angle-amplification ratio of over two is thus required.

In the mechanism 100, it can be seen that while the lever 124 is pivoted about the axis C-C which is adjacent the base 104, the claw wheel 120, the perforated plate 122 and the plastic wheel 118 are rotatable about the axis A-A, which is further from the base 104 than the axis C-C is. To allow the lever 124 to thus pivot about the axis C-C, the rivets 116, 126 are received through the curved slot 136 of the lever 124, thus allowing the lever 124 to swivel relative to the rivets 116, 126.

In addition, as the hole 148 of the perforated plate 122 is engaged via the rivet 150 and ring 154 with the slot 152, during downward pivotal movement of the lever 124 by about 20°, the platelet 156 of the slot 152 will bring the hole 148 of the perforated plate 122, and thus the perforated plate 122, into rotational movement about the axis A-A in the same direction by 45°. During such a movement, the rivet 150 will slide along the length of the slot 152 and relative to the lever 124, and downwardly from an upper position to a lower position. In the upward return movement of the lever 124, the perforated plate 122 will be brought into rotational movement in the same direction as the return pivotal movement of the lever 124. However, as discussed above, because of the construction of the claws 120b of the claw wheel 120 and holes 146 of the perforated plate 122, the claw wheel 120 (and thus the plastic wheel 118) will remain stationary in this return rotational movement of the perforated plate 122.

Figs. 6 to 13 show various views of the mechanism 100 in a ring-closed position in which the lever 124 is in its lower depressed position. In both Figs. 6 and 10, the wheel 118 is shown in dotted lines to reveal more details of the inner structure of the mechanism 100.

By reason of the construction of the mechanism 100 as discussed above and shown in the accompanying Figs. 1 to 13, when the mechanism 100 is in the ring-open configuration and in which the lever 124 is in its stable upper position, the lever 124 is not too close to the arches 106. Pieces of hole-punched paper may therefore be retrieved from or inserted into not only the posts 102, but also the arches 106, thus making the use of the mechanism 100 more convenient.

The mechanism 100 may be secured, e.g. by screws or rivets, to a substrate

(such as a board or a box file cover made of plastics, cardboard, metal or a combination of such materials) to form a paper- retain ing device, e.g. a writing board or box file.

Components forming a paper-retaining mechanism according to a second embodiment of the present invention are shown in Fig. 14, in which the mechanism is generally designated as 200.

The mechanism 200 has a generally planar base 204 to which two posts 202 are fixedly secured. Two arches 206 are joined with each other via an intervening bent rod 208 with which the arches 206 are integrally formed. The arches 206 and rod 208 are thus movable simultaneously. The arches 206 are engaged by two clamps 210 (of which only one is shown in Fig. 14) of the base 204 for pivotal movement between a ring-closed position in which free ends 206a of the arches 206 are in contact with and mate with free ends 202a of the posts 202 to form two closed rings for retaining pieces of hole-punched paper, and a ring-open position in which the free ends 206 of the arches 206 are out of contact with the free ends 202a of the posts 202, thus opening the rings, allowing pieces of hole-punched paper to be retrieved from or inserted into the posts 202 or the arches 206, as desired.

One side of a leaf spring 211 is fixed with the base 204. A second opposite side of the leaf spring 211 acts on the rod 208 from below to bias the arches 206 to the ring-open position.

The mechanism 200 includes a lever assembly operable to move the arches 206 between the ring-closed position and the ring-open position. Basically, the lever assembly includes a lever 224, a perforated metal plate 222, a metal claw wheel 220 and a plastic wheel 218. The claw wheel 220 and the perforated metal plate 222 combine to form a clutch assembly, to be further discussed below. A cover 224a (which may be made of a soft material, e.g. rubber) is provided for covering a longitudinal end 224b of the lever 224, for providing more comfort in use.

A plate 212 integrally formed with the base 204 extend upwardly from the base

204. The plate 212 has a hole 214 for receiving a rivet 216 for engaging the wheel 218, the claw wheel 220 and the perforated plate 222 with the plate 212 for rotation about a common axis D-D which is fixed relative to the base 204.

A rivet 240 is received through a hole 238 (which is adjacent the base 204) of the plate 212 and a hole 239 of the lever 224 so that the lever 224 is pivotable relative to the base 204 and the plate 212 about an axis F-F which is fixed relative to the base 204. A spring 228 is engaged with a rivet 226 received through a hole 236 of the lever 224. An upper longitudinal end 228a of the spring 228 is engaged with a bent portion 244 of the lever 224 and a lower longitudinal end 228b of the spring 228 is fixedly engaged with the base 204, so that, when duly assembled, the spring 228 biases the longitudinal end 224b of the lever 224 away from the base 204. At a second longitudinal end of the lever 224 is a slot 252 through which a rivet 250 and a ring 254 are received and for engaging with a hole 248 at a slightly protruding portion of the perforated plate 222. The width of the slot 252 allows the rivet 250 to slide within the slot 252 and thus relative to the perforated plate 222.

As can be seen in Fig. 14, the claw wheel 220 has four claws 220a pointing towards the wheel 218, each being received within a respective thin hole 218c of the wheel 218, so that, when duly assembled, the claw wheel 220 and the wheel 218 are simultaneously rotatable about the axis D-D. The claw wheel 220 also has four protrusions 220b extending towards the perforated plate 222, each being received within a respective hole 246 along a circumference of the plate 222. Each of the four protrusions 220b is provided at an end of a respective resilient leg 260 of the claw wheel 220, and the protrusions 220b have a curved and slanted surface (see Figs. 33 to 36).

As shown more clearly in Figs. 33 to 36, because of the shape of the protrusions 220b of the claw wheel 220, when the mechanism 200 is duly assembled, rotation of the perforated plate 222 in the direction indicated by the arrow G will bring about corresponding simultaneous rotation of the claw wheel 220 (and thus the wheel 218) in the same direction. On the other hand, when the perforated plate 222 rotates in a direction opposite to that indicated by the arrow G, thanks to the resilience of the legs 260 and the shape of the protrusions 220b, the plate 222 will slip over the protrusions 220b, and thus the claw wheel 220 and the wheel 218 will remain stationary.

Figs. 15 to 18 show a cycle of operation of the mechanism 200. In Fig. 15, the mechanism 200 is shown in a ring-closed configuration and with the lever 224 in its stable upper position. In this configuration, one of four equi-angularly disposed protruding parts 218a of the wheel 218 acts on the rod 208 to maintain the arches 206 in the ring-closed position, against the upward biasing force of the leaf spring 211. When the lever 224 is pressed to pivot downwardly (as shown in Fig. 16), the perforated plate 222 is brought into rotation in the direction indicated by the arrow G in Fig. 14, thus bringing the claw wheel 220 and the wheel 218 into simultaneous rotation in the same direction by 45°.

When the wheel 218 has thus rotated by 45°, one of four recesses 218b of the wheel 218 will face the rod 208 directly, thus allowing the leaf spring 211 to pivot upwardly to pivot the arches 206 away from the posts 202, thus opening the rings, as shown in Fig. 16.

When the downward pressing force on the lever 224 is released, the lever 224 will return to its stable upper position under the upward biasing force of the spring 228. During this upward return movement, the lever 224 will cause the perforated plate 222 to rotate in the direction opposite to that indicated by the arrow G. As discussed above, because of the shape of the protrusions 220b of the claw wheel 220, the claw wheel 220 (and thus the wheel 218) will remain stationary during rotation of the perforated plate 222 in the direction opposite to that indicated by the arrow G. The mechanism 200 will thus assume the ring-open configuration as shown in Fig. 17 and in which the lever 224 is back to its stable upper position.

When the user again presses the lever 224 downwardly to the position as shown in Fig. 18, the perforated plate 222 will be brought into rotation in the direction indicated by the arrow G in Fig. 14, thus bringing the claw wheel 220 and the wheel 218 into simultaneous rotation in the same direction by another 45°, to bring another protrusion 218a to bear on the bent rod 208, to pivot the arches 206 to the ring-closed configuration, against the upward biasing force of the leaf spring 211 , as shown in Fig. 18.

When the downward pressing force on the lever 224 is released, the spring 228 pivots the lever 224 back to its stable upper position. During this return pivotal movement of the lever 224, the lever 224 will cause the perforated plate 222 to rotate in the direction opposite to that indicated by the arrow G. Because of the shape of the protrusions 220b of the claw wheel 220, the claw wheel 220 (and thus the wheel 218) will remain stationary during rotation of the perforated plate 222 in the direction opposite to that indicated by the arrow G. The mechanism 200 will thus assume the ring-closed configuration as shown in Fig. 15 in which the lever 224 is back to its stable upper position.

Turning now to Figs. 37 to 40, such show various views of the lever 224 with exemplary dimensions and angles in one specific embodiment of this invention. Fig. 37 shows the orientation of the lever 224 in its stable upper position when the mechanism 200 is duly assembled, in which the line H-H is parallel to the plane of the base 204. It can be seen that, during operation, the lever 224 is only downwardly pivotable by at most around 20° (more particularly 19.9°) about the axis

F-F (see Fig. 14) through the hole 239. However, as discussed above, each downward pivotal movement of the lever 224 has to bring about rotation of the wheel

218 through 45°. This angle-amplification effect is achieved by the arrangement between the lever 224 and the perforated plate 222.

In particular, it can be seen that the lever 224 has a slot 252 with two platelets 256 each along a respective straight edge of the slot 252. As shown in Fig. 37, when the mechanism 200 is duly assembled and when the lever 224 is in its stable upper position, a longitudinal axis L-L of the slot 252 subtends an angle of 29.5° relative to the base 204. It is found in experiments that this angle may be between 25° and 35°, preferably between 29° and 30°, and is most preferably 29.5°.

As discussed above, the rivet 250 and the ring 254 are engaged with the hole 248 of the perforated plate 222 through the slot 252, such that the rivet 250 and the ring 252 are slidable within and relative to the slot 252. Such an action will also bring about corresponding rotational movement of the plate 222.

As shown in Figs. 19 to 32, when the lever 224 is in its stable upper position, the rivet 250 and ring 254 are at a lower longitudinal end of the slot 252 of the lever 224. When the lever 224 is pivoted downwardly (as indicated by the arrow G in Fig. 21 ) about the axis F-F, the slot 252 will be pivoted upwardly (in the sense of Fig. 21 ), and the side edges of the slot 252, in co-operation with the platelets 256, will force the rivet 252 and ring 254, and thus the perforated plate 222, to rotate about the axis D-D in the same direction. The rivet 252, the ring 254 and the hole 248 of the perforated plate 222 will thus rotate from a lower position to a higher position. Because of the orientation of the slot 252, downward pivotal movement of the lever 224 through around 20° will bring about rotation of the rivet 252, ring 254 and the perforated plate 222 in the same direction by 45°.

When the downward pressing force on the lever 224 is released, the lever 224 will return to its stable upper position upon the upward biasing force of the spring 228, whereupon the slot 252 will be pivoted downwardly (in the sense of Fig. 21 ), and the side edges of the slot 252, in co-operation with the platelets 256, will force the rivet 252 and ring 254, and thus the perforated plate 222, to rotate about the axis D-D in the direction opposite to that indicated by the arrow G, thus bringing the perforated plate 222 back to its position as shown in Fig. 21 , ready for the next step of operation. Again, because of the clutch assembly, the claw wheel 220 and the wheel 218 will remain stationary during the return pivotal movement of the lever 224.

As in the case of the mechanism 100 discussed above, the mechanism 200 may also be secured, e.g. by screws or rivets, to a substrate (such as a board or a box file cover made of plastics, cardboard, metal or a combination of such materials) to form a paper-retaining device, e.g. a writing board or box file.

Figs. 41 to 54 show various views of a paper-retaining mechanism according to a third embodiment of the present invention, in which the mechanism is generally designated as 300.

It can be seen that the structure of the mechanism 300 is very similar to that of the mechanism 200 discussed above, with a major difference being that a plastic wheel 318 of the mechanism 300 has three equi-angularly disposed protrusions

318a and three intervening recesses 318b. This means that every pivotal movement of a lever 324 from its upper position (as shown in Figs. 42 to 49) to its lower position ( as shown in Figs. 50 to 53) has to bring about a rotational movement of the wheel 318 by 60°. In this embodiment, the lever 324 moves through an angle of 26.3° during each such pivotal movement. This follows that the angle of rotation of the lever 324 is magnified by around 2.3 times to obtain the angle of rotation of the wheel 318. In order to achieve such a magnitude of magnification, it is designed such that when the lever 324 is in its upper position, the angle between an axis M-M of a slot 352 of the lever 324 and a base 304 of the mechanism 300 may be between 35° and 65°, and preferably between 38° and 55°. In this particular embodiment, this angle is 40°.

Figs. 55 to 67 show various views of a paper-retaining mechanism according to a fourth embodiment of the present invention, in which the mechanism is generally designated as 400.

It can be seen that the structure of the mechanism 400 is very similar to that of the mechanism 300 discussed above. The mechanism 400 also has a plastic wheel 418 with three equi-angularly disposed protrusions and three intervening recesses 418b. One major difference between the mechanism 400 and the mechanism 300 discussed above is that a lever 424 moves through 22.9° in each pivotal movement between its upper position (as shown in Figs. 56 to 63) and lower position (as shown in Figs. 64 to 67). As each downward pivotal movement of the lever 424 from its upper position to its lower position has to bring about a rotational movement of 60° in the wheel 418, the magnitude of magnification is around 2.62. In order to achieve such a magnitude of magnification, it is designed such that when the lever 424 is in its upper position (to which it is biased), the angle between an axis P-P of a slot 452 of the lever 424 and a base 404 is between 30° and 60°, such as 53.5°.

Each of the mechanisms 300, 400 may also be secured, e.g. by screws or rivets, to a substrate (such as a board or a box file cover made of plastics, cardboard, metal or a combination of such materials) to form a paper-retaining device, e.g. a writing board or box file.

It should be understood that the above only illustrates examples whereby the present invention may be carried out, and that various modifications and/or alterations may be made thereto without departing from the spirit of the invention.

It should also be understood that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any appropriate sub-combinations.

Claims

CLAIMS:

1. A paper-retaining mechanism (100, 200, 300, 400) including: a base (104, 204, 304, 404); at least two post members (102, 202) secured to said base; a pair of arch members (106, 206) joined with each other for simultaneous movement, wherein said arch members are movable relative to said post members between a closed position in which said arch members are in contact with said post members to form two closed rings and an open position in which said arch members are out of contact with said post members to open said rings; and a lever assembly operable to move said arch members between said closed position and said open position; wherein said lever assembly includes a lever member (124, 224, 324, 424), a clutch assembly (120, 122; 220, 222), and a rotatable member (118, 218, 318, 418); characterized in that said lever member has a slot (152, 252, 352, 452), that said clutch assembly is engaged with said lever member by engagement means

(150, 154; 250, 254) at least partly received through said slot of said lever member, and that said engagement means is slidably movable within and relative to said slot during operation of said lever assembly.

2. A mechanism according to Claim 1 further characterized in that said lever member is pivotable relative to said base about a first axis (C-C, F-F) and said clutch assembly is swivellable relative to said base about a second axis (A-A, D-D).

3. A mechanism according to Claim 2 further characterized in that said rotatable member is rotatable relative to said base about said second axis.

4. A mechanism according to Claim 1 further characterized in that said clutch assembly includes a first member (120, 220) and a second member (122, 222).

5. A mechanism according to Claim 4 further characterized in that said first member of said clutch assembly is engaged with said rotatable member for simultaneous movement.

6. A mechanism according to Claim 4 further characterized in that said second member of said clutch assembly comprises a plurality of openings (146, 246).

7. A mechanism according to Claim 6 further characterized in that said first member of said clutch assembly comprises a plurality of protrusions (120b, 220b) extending towards said second member of said clutch assembly.

8. A mechanism according to Claim 7 further characterized in that each said protrusion of said first member of said clutch assembly is received at least partly within a respective opening of said second member of said clutch assembly.

9. A mechanism according to Claim 4 further characterized in that rotation of said second member of said clutch assembly in a first direction (G) about said second axis brings about corresponding rotational movement of said first member of said clutch assembly in said first direction and said first member of said clutch assembly remains stationary during rotation of said second member of said clutch assembly about said second axis in a second direction opposite to said first direction.

10. A mechanism according to Claim 2 further characterized in that said lever member is pivotable about said first axis from an upper position to a lower position to move said arch members from said closed position to said open position, and that said lever member is pivotable about said first axis from said upper position to said lower position to move said arch members from said open position to said closed position.

1 1. A mechanism according to Claim 10 further characterized in that when said lever member is pivoted about said first axis from said upper position to said lower position, a part (248) of said clutch assembly engaged with said engagement means moves from a lower position to an upper position.

12. A mechanism according to Claim 10 further characterized in that when said lever member is pivoted about said first axis from said upper position to said lower position, a part (148) of said clutch assembly engaged with said engagement means moves from an upper position to a lower position.

13. A mechanism according to Claim 10 further characterized in that said lever member is biased towards said upper position.

14. A mechanism according to Claim 13 further characterized in that when said lever member is in said upper position, a longitudinal axis (L-L, M-M, P-P) of said slot is inclined relative to said base by 25° to 60°.

15. A mechanism according to Claim 14 further characterized in that when said lever member is in said upper position, said longitudinal axis of said slot is inclined relative to said base by 29° to 55°.

16. A mechanism according to Claim 15 further characterized in that when said lever member is in said upper position, said longitudinal axis of said slot is inclined relative to said base by 29.5°, 40° or 53.5°.

17. A paper-retaining device including a substrate engaged with a paper-retaining mechanism (100, 200, 300, 400) according to Claim 1.