GB2054878A

GB2054878A - Camera having slidable lens cover

Info

Publication number: GB2054878A
Application number: GB8022241A
Authority: GB
Original assignee: Olympus Optical Co Ltd
Current assignee: Olympus Corp
Priority date: 1979-07-13
Filing date: 1980-07-08
Publication date: 1981-02-18
Also published as: DE3026215A1; JPS5616130U; GB2054878B; FR2461275A1; FR2461275B1; JPS5829452Y2

Abstract

A camera has a slidable lens cover 2 which in the closed position adjusts the lens 7 to a normal focused position of 5 m. (when it has just been used at another focused position) to enable rapid shooting without refocusing. Two driven members in the form of pins 14 and 15 on a focus adjusting member 9 are moved to the central position shown by drive members in the form of resilient blades 16 and 17 on the inside of cover 2. In another embodiment (Figs. 79), a single pin (22), which remains in a concealed position, is moved by a drive member (23) having a non-symmetrical V-shaped notch forming a pair of cam surfaces. <IMAGE>

Description

SPECIFICATION Camera with lens protective cover The invention relates to a camera with a lens protective cover, and more particularly, to a camera with a lens protective cover which is movable between a first position in which it covers the front of a taking lens and a second position in which it reveals the lens.

A variety of proposals have been made to provide a protective cover which is adapted to cover the front of a taking lens which is disposed for axial movement along the optical axis thereof for focusing purpose.

Such a camera is convenient for portable use and is advantageously used in taking a snap shot.

In such instance, it is desirable that the camera can be immediately operated for whatever is the range to an object being photographed.

Specifically, when taking a picture of an object which is at rest, a shutter release operation may be initiated after performing an accurate focusing adjustment. However, for a moving object, an optimum shutter chance may be missed during the time a focusing adjustment is being made in order to take the picture of the object at a given moment. Hence, it is desirable that the time required for focusing adjustment be minimized.

On the other hand, a taking lens has a depth of field associated therewith which is determined by the focal length of the lens, the diaphragm aperture and the range to an object being photographed (to which a focusing operation is adjusted). The depth of field (focus) represents a region within which an object, though not exactly focused, can be viewed as a sharply focused image by the human eye. By way of example, when a diaphragm aperture of F.8 is chosen with a lens having a focal length of 35mm, a range from approximately 2.5m to infinity represents the depth of field if the range setting is adjusted to 5m. When the range setting is adjusted to 3m, the depth of field will be approximately from 1 .8m to 8m.In other words, when the described taking lens is used with a diaphragm aperture of F.8, substantially satisfactory pictures can be taken for a majority of objects being photographed if a focusing ring is adjusted to a position corresponding to the distance of approximately 3m to 5m. When such value varies with the range to which the taking lens is focused it is to be understood that there exists an adjusted lens range, herein referred to as a normal focused position, associated with a particular taking lens which satisfies the photographing requirements for a majority of objects being photographed.

Consequently, for a camera with a lens protective cover, it is desirable that the taking lens of a camera be located at its normal focused position whenever the cover is opened so that a majority of objects can be immediately photographed.

There has been proposed a taking lens translating device for a camera with a lens protective cover (see U.S. Patent No. 4,171,894, German Patent Application No. P2901991.3) in which, if the taking lens is translated forwardly to project beyond the cover in order to take a picture of an object located at a nearest point, the taking lens can be retracted to a position corresponding to infinity or its normal focused position as the cover is moved to its lens covering position whenever the camera is not in use. Such device permits the height of projection of the lens protective cover to be reduced to a value which corresponds to the maximum retraction of the taking lens, thus enabling a reduction in the overall fore-and-aft thickness of the camera.

However, when considered from the standpoint that the taking lens should be located at its normal focused position so that a picture can be taken for a majority of objects immediately upon opening the lens protective cover, it is desirable that the taking lens be returned to its normal focused position whenever the lens protective cover is opened again if it has been retracted beyond the normal focused position or even located at a position corresponding to infinity as a result of the need to take a picture located at infinity.

In view of the foregoing, it is an object of the invention to provide a camera which has a lens protective cover such that the taking lens is moved either rearwardly or forwardly from its previously focused position corresponding to infinity or the nearest point, so that it assumes its normal focused position when the lens protective cover is moved to its first position covering the taking lens.

In accordance with the invention, a cover is provided with a lens protective cover which is slidably disposed on the outside of the body of the camera between a first position in which it covers the front of a taking lens and a second position in which it reveals the taking lens and with a focus adjusting member disposed for angular movement about the optical axis of the taking lens to cause a movement of the taking lens in the direction of the optical axis thereof for focusing purposes, at least one driven member being fixedly provided on the focus adjusting member, and a corresponding drive member being provided on the lens protective cover and being adapted to engage the driven member to cause angular movement of the focus adjusting member until the taking lens reaches a normal focused position, as the cover is moved to its first position where it covers the taking lens.

Hence, when the lens protective cover is opened to take a picture for the next time, the taking lens is already in its normal focused position to satisfy the minimum focusing requirements which enable pictures of a majority of objects to be taken without requiring a focusing adjustment. In this manner, the camera can be effectively made responsive to a rapidly moving object, preventing a critical shutter chance from being lost.

Such a photographic camera is easily operable by a beginner who is not well acquainted with a focusing adjustment, since pictures can be taken without requiring a focusing adjustment.

The invention is further described, by way of example, with reference to the drawings, in which: Fig. 1 is a perspective view of a camera according to the invention, with a lens protective cover located to cover a taking lens; Fig. 2 is a perspective view of the camera shown in Fig. 1 , with the lens protective cover located to reveal the taking lens; Fig. 3 is a front view of the camera shown in Fig. 1 when the lens protective cover is located to reveal the taking lens, which is adjusted to a photographing position focused onto an object which is beyond or on the remote side of the normal focused position;; Fig. 4 is a front view similar to Fig. 3, illustrating the condition which prevails when the lens protective cover is located to reveal the taking lens and when the latter is adjusted to a photographing position located nearer than the normal focused position; Fig. 5 is a front view of the camera shown in Fig. 1 when the lens protective cover is located to cover the taking lens, with the cover being shown partly broken away; Fig. 6 is a front view of the camera shown in Fig. 1 when the lens protective cover is moved from its first position covering the taking lens to its second position in which it reveals the latter; Fig. 7 is a front view of a camera according to another embodiment of the invention when the lens protective cover is located to reveal taking lens and the latter is adjusted to a photographing position near that the normal focused position;; Fig. 8 is a front view of the camera shown in Fig. 7 when the lens protective cover is located to reveal the taking lens and the latter is adjusted to a photographing position beyond the normal focused position; and Fig. 9 is front view of the camera shown in Fig.

7 when the lens protective cover is located to cover the taking lens, with the cover being shown partly broken away.

Referring to Figs. 1 and 2, a camera 1 has slidable lens protective cover 2 which is constructed according to one embodiment of the invention. In Fig. 1 , the lens protective cover 2 is shown in its first position where it covers the front of a taking lens 7 while it is shown in its second position where it reveals the taking lens in Fig. 2.

As shown, the lens protective cover 2 is adapted to enclose part of a front face 1 a, a top face 1 b and a rear face 1 c of the camera 1, and is centrally formed with a trapezoidal shroud 2a having a height of projection which corresponds to that of the taking lens 7. The cover 2 is disposed so as to be movable in a direction perpendicular to the optical axis of the taking lens as guided by suitable guide members, not shown, between its first position in which it covers the front of the taking lens 7 and its second position in which it reveals the taking lens 7. When the lens protective cover 2 is moved to its first position where it covers the taking lens 7, it also covers a viewfinder window 4 and a shutter release button 5.When the cover 2 slides to its second position where it reveals the taking lens 7, a film rewind knob 6 which is disposed on the top face 1 b of the camera 1 and which also serves as a lock for a rear lid is covered by the cover 2 (see Fig. 2).

The taking lens 7 is carried by a lens barrel 8 which is centrally disposed in the front face 1 a of the camera 7. On its forward portion, the lens barrel 7 is integrally formed with a range or focus adjusting member 9 in the form of a ring. In its rear portion (not shown), the lens barrel is formed with a well known helicoid screw which may be threadably engaged with a corresponding helicoid screw integrally formed in the body of the camera 1, whereby the taking lens 7 is carried so as to be movable in the direction of the optical axis thereof.

By turning the focus adjusting member 9, the taking lens 7 may be moved either forwardly or rearwardly along the optical axis for focusing purposes.

The focus adjusting member 9 is integrally provided with an operating element 10, which may be engaged by a finger to be moved angularly to cause an angular movement of the focus adjusting member 9. On its front surface, the focus adjusting member 9 is formed with a range scale 11 having indications from 0.5m to oo (infinity) which may be aligned with a pointer 13 inscribed on the body of the camera 1. In its out periphery which is invisible from the exterior, the member is formed with a notch 9a (see Fig. 3) and the extent of the angular movement of the focus adjusting member 9 is limited by the abutment of a stop pin 12, fixedly mounted on the body of the camera 1, against one or other end of the notch 9a.By turning the focus adjusting member 9 within the extent limited in this manner, any indication on the range scale 11 from "0.5m" to co may be brought into alignment with the pointer 13, thus adjusting the focused position of the taking lens 7 from its nearest point (0.5m) to infinity (co).

In accordance with the invention, a first driven member 14 in the form of a projecting pin is fixedly mounted on the front face of the focus adjusting member 9 in alignment with the indication of "5m" of the range scale 11 or in alignment with a normal focused position of the taking lens 7, in a manner not to prevent the sight of the indication. Also, a second driven member 1 5, again in the form of a projecting pin, is located on the front surface of the focus adjusting member 9 at a position diametrically opposite to the first driven member 14. Consequently, when the focus adjusting member 9 is adjusted so that the indication "5m" on the range scale 11 is aligned with the pointer 13, the first and the second driven members 14, 15 will be on a line which is parallel to the vertical edges 2b of the lens protective cover 2.

Referring to Figs. 3 and 4, it will be noted that a first and second drive members 16, 1 7 formed as resilient blades are secured to the internal surface of the shroud 2a of the lens protective cover 2, by means of fasteners 1 8, so as to be located coplanar with the first and second driven members, 14, 15. Each of these drive members 16, 17 is formed with a notch 1 6b or 1 7b which extends parallel to the vertical edge 2b, thereby defining tabs 1 6a, 1 7a at portions of the drive members 16, 1 7 which are located nearer the edge 2b.These tabs 1 6a, 1 7a extend along lines which are parallel to the edge 2b, and are adapted to engage the driven members 14, 1 5. When the lens protective cover 2 has moved to its first position where it covers the taking lens 7, one or other of these tabs engages the respective driven member 14 or 1 5 to cause corresponding angular movement of the focus adjusting member 9.

In operation, when it is desired to take a picture initially, the lens protective cover 2 is slid to its position shown in Figs. 2 and 3 where it reveals the taking lens 7. As the cover slides, the finder window 4, the operating element 10 and the release button 5 are revealed while the rewind knob 6 is covered, making it not possible to open the rear lid. The operating element 10 may now be turned to cause an angular movement of the focus adjusting member 9, and after the focusing adjustment is completed, the release button 5 may be depressed to take a picture.Assuming that the focus adjusting member 9 is adjusted to a position which is more remote than the normal focused position of "5m" of the taking lens 7, for example, to a position where the indication "co" is aligned with the pointer 1 3, one of the driven members 14, 15, that is, the first driven member 14 is located close to the tab 1 6a of the corresponding first drive member 1 6 as shown in Fig. 3. Conversely, if the focus adjusting member 9 is adjusted to a position which is less than the normal focused position, for example, to a range of "0.5m", the second driven member 1 5 will be located close to the tab 1 7a of the corresponding second drive member 17, as shown in Fig. 4.

Therefore, when the lens protective cover 2 is moved to its first position where it covers the taking lens 7 after the completion of a photographing operation, one of the tabs 1 6a, 1 7a will engage the respective one of the first and second driven members 14, 1 5. Specifically, as the lens protective cover 2 is closed, the focus adjusting member 9 is forcibly turned either clockwise or counter-clockwise, and when the movement of the cover 2 is completed to cover the taking lens 7, both tabs 1 6a, 1 7a will be positioned in abutment against the driven members 14, 1 5, respectively.It is to be noted that at the time the lens protective cover 2 has completely reached the position where it covers the taking lens 7, it would be necessary to provide a perfect and close abutment between the driven members 14, 15 and the tabs 1 6a, 1 7a, but the resilience inherent in the tabs 1 6a, 1 7a, which is produced as a result of the formation of the notches 1 6b, 1 7b in the drive members 16, 17, accommodates any slight tolerance in the sizes and locations of the driven members 14, 1 5 and the drive members 1 6, 1 7 when they bear against each other.

When the tabs 1 6a, 1 7a of the drive members 1 6, 1 7 move into abutment against the driven members 14, 1 5, respectively, these driven members will be aligned along a line parallel to the edges 2b of the lens protective cover 2 as mentioned previously, maintaining the taking lens 7 at its normal focused position. Thus it will be seen that, when the described lens protective cover 2 is opened, the taking lens 7 assumes its normal focused position at a range of 5m indicated in Fig. 6. Hence under this condition, the camera is preconditioned to provide a minimum sharpness to take pictures without requiring a further focusing adjustment, and hence enables an instantaneous photographing operation.

Figs. 7 to 9 show a camera 21 incorporating a lens protective cover 2 constructed according to another embodiment of the invention. Parts corresponding to those shown in Figs. 1 to 6 are designated by the same reference characters in Figs. 7 to 9. In the present embodiment, a single driven member 22 is fixedly mounted on the focus adjusting member 9 at a location which is covered by the lens protective cover 2 when the latter is open. A drive member 23 in the form of a cam plate is secured to the internal surface of the shroud 2a of the lens protective cover 2 by means of fasteners 24. The side of the drive member 23 which faces the driven member 22 is formed with a non-symmetrical V-shaped notch, defining first and second or upper and lower cam surfaces 23a, 23b.As will be noted from Fig. 7, the first cam surface 23a of the drive member 23 will be located adjacent to the driven member 22 when the focus adjusting member 9 is adjusted to a range less than the normal focused position, for example, to a nearest point of "0.5m" on the range scale 11 while the second cam surface 23b will be located adjacent to the driven member 22 when the focus adjusting member 9 is adjusted to a range greater than the normal focused position, for example, to "co" on the range scale 11 as indicated in Fig. 9. A base 23ctefined between the first and second cam surfaces 23a, 23b is formed on the drive member 23 so as to be located opposite to the driven member 22 when the focus adjusting member 9 is adjusted to its normal focused position.

In operation, when the lens protective cover 2 is moved to cover the taking lens 7 after completion of a photographing operation, the drive member 23 is carried therewith, whereby the first or the second cam surface 23a or 23b of the drive member 23 is brought into abutment with the driven member 22. In this manner, the focus adjusting member 9, with which the driven member 22 is integrally formed, is forcedly driven to rotate either clockwise or counter-clockwise until the base 23c of the notch formed in the drive member 23 bears against the driven member 22 to locate the taking lens 7 at its normal focused position upon completion of the movement of the cover 2 to its first position, as indicated in Fig. 9.

It will be seen that in the present embodiment, the focus adjusting member 9 of the camera 21 requires the single driven member 20, which remains concealed below the cover 2 even when the lens protective cover 2 is moved ta reveal the taking lens 7, thus presenting a neat appearance.

In the described embodiments, the drive members 16, 17 or the drive member 23 of the camera 1 are separate from the lens protective cover 2, but it should be understood that such drive member or members may be formed integrally with the cover.

Claims

1. A camera provided with a lens protective cover which is slidably disposed on the outside of the body of the camera between a first position in which it covers the front of a taking lens and a second position in which it reveals the taking lens, and with a focus adjusting member disposed for angular movement about the optical axis of the taking lens to cause a movement of the taking lens in the direction of the optical axis thereof for focusing purposes, at least one driven member being fixedly provided on the focus adjusting member and a corresponding drive member being provided on the lens protective cover and being adapted to engage the driven member to cause angular movement of the focus adjusting member until the taking lens reaches a normal focused position, as the cover is mpved to its first position where it covers the taking lens.

2. A camera according to claim 1, in which there are a pair of driven members located diametrically opposite to each other on the focus adjusting member.

3. A camera according to claim 2, in which there are a pair of drive members formed of resilient material and secured to the internal surface of the lens protective cover in opposing relationship with the driven members.

4. A camera according to claim 3, in which each drive member is notched to define a resilient tab which is located nearer the corresponding driven member.

5. A camera according to claim 1 in which there is a single driven member which is located to remain concealed beneath the lens protective cover when when the latter is in its second position where it reveals the taking lens.

6. A camera according to claim 5, in which the side of the drive member which faces the driven member is formed with a non-symmetrical V-shaped notch to define a pair of cam surfaces which engage the drive member whenever the taking lens is located at other than the normal focused position, a base defined between the pair of cam surfaces being located opposite to the drive member when the lens protective cover reaches its first position where it covers the taking lens.

7. A camera constructed substantially as herein described with reference to and as illustrated in the drawings.