GB2030713A - Motorised Camera - Google Patents

Abstract

In a motorised camera, the motor is de-energised on detection of a perforation corresponding to the next frame to be exposed. On operation of shutter release 2 (closing switch 18 and releasing spring biased connecting rod 40, thereby operating shutter 24 and closing switch 19 and also closing switch 21/22), film advance motor 16 becomes energised and remains energised on release of shutter release 2 by centrifugal closing of switch 20. Rod 40 is thereby moved against its spring bias to recharge shutter 24 and film 7 is advanced, spring biased detector lever 9 thereby being withdrawn from perforation 7a by means of cam pin 1b until the next perforation is sensed when lever 9 advances into the perforator, releasing lever 12, opening switch 21/22 and closing switch 22/23 to short circuit motor 16 (and open switch 20). <IMAGE>

Description

SPECIFICATION A Still Photographic Camera This invention relates to a still photographic camera for use with film of the kind having perforations therein corresponding to the positions of respective exposure frames and contained within a cassette including a storage compartment from which the film can be progressively transported across an exposure window into a winding compartment.

One known type of still photographic camera for use with film of the kind specified includes an electric motor for transporting the film and for controlling operation of the shutter, and a detector which scans the perforations in the film and, each time one of these perforations is detected, opens a switch in a power supply circuit of the motor and preferably short-circuits the motor. However, known cameras of this type, including those for use with the so-called 110 cassettes, are relatively large so that the advantages resulting from the use of a motorised film transport are largely outweighed by the enlarged camera housing.

An object of the present invention is therefore to provide a camera of the type described in the preceding paragraph in which the external dimensions of the camera can be reduced as compared with known cameras of this type.

Accordingiy, the invention resides in a still photographic camera for use with film of the kind having perforations therein corresponding to the positions of respective exposure frames and contained within a cassette including a storage compartment from which the film can be progressively transported across an exposure window into a winding compartment, the camera including a shutter, an electric motor operable to wind on a film of the kind specified loaded in the camera in use and to prime the shutter, the electric motor being arranged in the camera so that, when looking in the direction of an object to be photographed, the motor is located in front of the region of the camera which, in use, receives the winding compartment of a film cassette, a shutter release member, means for detecting perforations in a film of the kind loaded in the camera in use, and switch means connected in a power supply circuit of the motor and operable, in response to detection by said detecting means of a perforation in a film of the kind specified, to deenergise the motor.

The accompanying drawing isan exploded perspective view, not to scale, of a camera according to one example of the present invention.

Referring to the drawing, the camera shown is adapted to receive a film cassette 8 having a storage compartment from which a film 7 can be progressively transported across an exposure window and into a winding compartment where the film is wound onto a take-up spool. Formed in the film are a plurality of longitudinally spaced perforations 7a (only one shown), one perforation being provided for each exposure to be made on the film.

The camera includes a housing 1, only part of which is shown for the sake of simplicity, and a shutter release button 2 which is mounted in one wall of the housing. The button 2 is movable into the housing in the direction of the arrow 3 to pivot a two-armed release lever 6 in an anti-clockwise direction about an axis 4 and against the action of a spring 5, the lever 6 extending parallel with the transport direction of the film 7. One arm of the lever 6 defines a shoulder 6a, while the other arm 6b of the lever defines the operating member of an electrical switch 1 8 which is arranged to be closed by the lever arm 6b when the button 2 is moved in the direction of the arrow 3.

Located within the housing 1 between a stop 1 a and a control cam 1 b is a detector lever 9 which, in the position shown, engages in one of the perforations 7a in the film 7. The lever 9 is biased towards the film 7 by a spring 10 and towards the stop 1 a by e further spring 11. In the position shown the lever 9 is held in engagement with the control cam 1 b against the action of the spring 11. The lever 9 is formed with a longitudinally extending slot 9a and with an arm 9b which extends perpendicular to the operating direction of the springs 10, 11 into the path of movement of one arm 1 2a of a three-armed control lever 12.The lever 12 is pivotable about an axis 13 and has a second, short arm 1 2b formed with a peg 1 2c which engages in a slot 1 4a formed in one arm of a two-armed lever 14.

The lever 14 is movable angularly about an axis 1 5 and defines a control edge 1 4b at the free end of its other arm. The third, relatively long arm 1 2b of the control lever is generally L-shaped and is formed with a bore 12g in one limb, a peg 12f at the junction between the iimbs and a peg 1 2e at the free end of its other limb. The lever 1 2 is arranged so that the major dimension defined by the arms 12a,12b extends parallel with the transport direction of the film 7.

Transport of the film 7 is effected by an electric motor 1 6 which is located directly in front of the region of the camera which, in use, receives the winding compartment of the cassette 8. To power the motor 1 6 are two torch batteries 1 7 which are located adjacent the region of the camera which in use receive the storage compartment of the cassette 8 and which extend generally parallel with the optical axis of the camera shutter 24.

Electrically connected in series between the batteries 1 7 and one terminal of the motor 1 6 are the switch 1 8 and a second switch 19, with a third switch 20 being connected in parallel with the switches 1 8, 1 9. Connected between the batteries 1 7 and the other terminal of the motor 1 6 is a fourth switch 21,22, having its movable contact 22 common with a fifth switch 22, 23 operable to short circuit the motor 1 6. The contact 22 is resiliently urged to close the switch 21, 22 but is movable by the peg 1 2e in a direction to open the switch 21,22 and close the switch 22, 23.

The contacts of the switch 1 9 are arranged so as to lie in the path of a peg 24a movable with the camera shutter 24 such that the switch 1 9 is closed at or near one end of the shutter operation.

Priming of the shutter 24 is effected by a pinion 24b which is in meshing engagement with a rack 40e defined by a connecting rod 40 and which operates by way of a one-way coupling (not shown) so as to be rotatable in a clockwise direction to prime the shutter and to be freely rotatable in the opposite direction. Release of the shutter is controlled in the manner described below by a peg 24c provided on the shutter 24 and an arm 40d projecting from the connecting rod 40.

The motor 16 drives a pinion 1 6a under the control of a brake lever 25. The brake lever 25 includes a peg 25a which engages in the bore 1 2g of the control lever 12 such that, according to the position of the control lever 12, the brake lever 25 is engageable with the pinion 1 6a to lock the pinion. Drivingly coupled with the pinion 1 6a is a reduction gear 26 including a gear wheel 26a which meshes with a further gear wheel 27. The gear wheel 27 in turn meshes with a gear wheel 28 of a centrifugal switch 29 including an operating peg 29a which maintains the switch 20 closed while the motor 1 6 is running.It is to be appceciated that, in order to more clearly explain the operation of the camera, the gear wheel 28 is shown twice in the drawing.

Rigidly connected to the gear whets 27 is a gear wheel 30 which meshes with a large diameter gear wheel 31 which in turn has a further gear wheel 32 rigidlyconnected thereto.

The gear wheel 32 meshes with a gear wheel 33 which is coupled by way of a gear wheel 34 to a further gear wheel 35 which is drivingly connected to the take-up spool of the film cassette. All the gear wheels consist of thin metal or plastic, generally planar toothed wheels so that the entire gear wheel drive measures only a few millimetres in height.

Engageable with the gear wheel 27 is a gear segment 37 which is rigidly mounted on a rotatable shaft 36 together with a cam disc 38 such that, depending on the angular position of the cam disc 38, the gear segment 37 can mesh with the gear wheel 27 to be driven by the gear wheel 27. Pivotally connected to the cam disc 38 by a pin 39 is a connecting rod 40 which includes a control peg 40a and first and second shoulders 40b, 40c respectively as well as the arm 40d, and the rack 40e. The connecting rod 40 extends parallel with the transport direction of the film 7 and a spring 41 biases the connecting rod 40 to the left, as viewed in the drawing, i.e. in the opposite direction to that required for priming the shutter.

The peg 1 2f of the lever 12 is slidably received in a slot 42a formed in one arm of a further 3 armed lever 42 having a curved second arm 42b located in the path of movement of the peg 40a.

The third arm of the lever 42 defines a retaining edge 42c and is urged against a stop 1 C by a spring 43 which also urges a locking edge 44a of a further lever 44 towards the third arm of the lever 42. The lever 44 is pivotable about a shaft 45 and the free end 44b of the lever 44 is urged by the spring 43 against one end of the connecting rod 40. A further lever 46 is pivotally mounted on a shaft 47 and is urged by a spring 48 towards the lever 14 and the connecting rod 40 so as to be engageable with either the control edge 14b or the shoulder 40b.

The levers 12, 44, 46, 42 are arranged so that together they extend mainly parallel with the film transport direction. Moreover, the control means defined by the levers 12, 9, 42, 44 and the rod 40 is of overall height less than or equal to the overall height of the gear wheel drive defined by the pinion 1 6a and the gear wheels 26 to 38.

In order to understand operation of the camera described above, it is to be appreciated that the camera is shown in the drawing with the shutter 24 primed and film 7 at the end of its movement necessary to allow a new exposure to be taken. In this position, the switches 18, 19, 20 and 21 are all open and the movable contact 22 is urged by the peg 1 2e to close the switch 22, 23 so that the motor 1 6 is short circuited. In addition, the shoulder 6a of the release lever 6 is located in front of the second shoulder 40c of the connecting rod 40 so as to retain the connecting rod in its primed position. The lever 46 is at this time held by the control edge 1 4b of the lever 14, out of the path of the shoulder 40b of the connecting rod 40.

If the shutter release button 2 is now depressed, the lever 6 is pivoted in an anticlockwise direction so that the switch 18 is closed by the arm 6b and then remains closed until the button is released. At the same time, the shoulder 6a is moved clear of the shoulder 40c so that the connecting rod is released and starts moving under the action of the spring 41 in the opposite direction to the film transport direction whereby the cam disc 38 and the rear segment 37 begin to rotate. As the connecting rod 40 reaches the end of its stroke the arm 40d operates the shutter release peg 24c so as to release the shutter 24 and effect a photographic exposure. At the end of the shutter cycle, the peg 24a closes the switch 1 9 so that now both the switches 1 8, 1 9 are closed.

During movement of the connecting rod 40 to release the shutter 24, the gear segment 37 is rotated by an amoumt such that its first tooth meshes with the gear wheel 32, while the peg 40a of the connecting rod 40 pivots the lever 42 anti-clockwise so that the locking edge 44a of the lever 44 can move under the action of the spring 43 into engagement with the holding edge 42c so as to hold the lever 42 in this pivoted position.

The pivotal movement imparted to the lever 42 in turn drives the lever 12 clockwise so that the lever arm 1 2a disengages from the lever 9, and the lever 14 is pivoted anti-clockwise out of engagement with the lever 46, so that the latter bearsagainst the connecting rod 40 under the action of its biasing spring 48. At the same time the brake lever 25 is lifted away from the motor pinion 1 6a and the peg 1 2e is moved away from the movable contact 22 whereby the switch 22, 23 is opened and the switch 21,22 is now closed. Thus, since the switches 1 8, 1 9 and 21, 22 are now all closed, the motor 1 6 is energised so that the pinion 1 6a rotates and the centrifugal switch 29a closes the switch 20.It will be appreciated that the motor 1 6 will now remain energised through the switch 20 until the switch 20 is re-opened and hence the button 2 can now be released and the shutter 24 reprimed, whereby the switches 1 8, 1 9 are again opened.

As the motor 1 6 rotates the pinion 16a, the gear segment 37 is driven by way of the reduction gear 26 and the gear wheels 27, 30, 31 and 32 to rotate the cam disc 38 in an anti-clockwise direction. The connecting rod 40 is thereby moved in the film transport direction against the action of the spring 41 so that the rack 40e causes the pinion 24b to re-set the shutter 24.

The peg 24a is thereby moved back into the position shown in the drawing so as to re-open the switch 19, although the motor 1 6 remains energised by means of the switches 20 and 21, 22.

Furthermore, as the pinion 1 6a rotates, it operates by way of the reduction gear 26 and the gear wheels 27 and 30 to 35 to rotate the takeup spool of the film cassette so as to transport the film 7. During the initial phase of the film transport, the lever 9 is lifted out of the perforation 7a by means of the control cam 1 b and is then urged back against the stop 1 a by the spring 11. The lever 9 is thus unable to move back into the same perforations 7a, although is urged by the spring 10 to bear against the film 7.

In this position of the lever 9, the arm 9a engages the arm 1 2a of the lever 12.

The connecting rod 40 continues to move against the action of the spring 41 until, after one rotation of the cam disc 38, the rod 40 again resumes the position shown in the drawing. In this position, said one end of the connecting rod 40 pivots the lever 44 against the action of the spring 43 to disengage the edge 44a from the lever 42, while the gear segment 37 becomes disengaged from the gear wheel 32. At this stage, the film transport is not complete so that the lever 9 still bears against an imperforate region of the film 7 and the arm 9b engages the arm 1 2a to prevent the levers 12, 14 and 42 returning to their rest positions. Thus the switches 20 and 21, 22 remain closed so that the motor 1 6 continues film transport.Moreover, since the control edge 1 4b is held clear of the lever 46, the lever 46 is urged by the spring 48 behind the shoulder 40b to prevent the connecting rod 40 being returned by the spring 41 to its rest position before film transport is complete.

When the next perforation 7a on the film 7 moves into alignment with the lever 9, the latter is urged by the spring 10 into the perforation so that the arm 9b releases the arm 12a. The lever 1 2 can then rotate anti-clockwise to impart clockwise rotation to the lever 42 to cause the peg 1 2e to open the switch 21,22 and close the switch 22, 23. The motor 1 6 is thereby shortcircuited and rapidly comes to rest to terminate film transport, the centrifugal switch 29 then opening the switch 20.Moreover, during anticlockwise rotation of the lever 12, the brake lever 25 is re-engaged with the pinion 1 6a and the control edge 1 4b of the lever 14 pivots the lever 46 away from the shoulder 40b so that all the camera components are again in the position shown in the drawing.

From the above, it will be manifest that the gear segment 37 will become operatively disengaged from the gear wheel 32 as soon as the connecting rod 40 has been returned to its starting position, shown in the drawing.

Thereafter, the motor 1 6 will continue to operate until the film 7 has been wound on by the correct amount. In each winding-on operation, the same length of film is wound onto the take-up spool of the cassette. However, due to the progressively increasing diameter of the film roll on this spool, the amount by which the gear wheel 35 rotates during each winding-on operation will vary. By virtue of the gear segment 37 becoming disengaged from the gear wheel 32, the amount of movement of the connecting rod 40 is independent of the amount of movement of the gear wheel 35.

In order to make a series of exposures consecutively, the release button 2 is maintained in its actuated condition for the duration of the exposures. The sequence of each exposure and each subsequent film transport then occurs in the manner defined above, with the switch 1 8 remaining closed and the shoulder 6a remaining free of the shoulder 40c for the duration of the exposures. In the period between one complete rotation of the cam disc 38 and the termination of the film transport required to advance the film for the next exposure, the gear segment 37 is disengaged from the gear wheel 32 and the lever 46 is located in front of the shoulder 40b to prevent movement of the connecting rod 40.As will be appreciated from the foregoing comments, the connecting rod 40 is released when the lever 9 engages the next perforation 7a in the film, that is when the required film transport is completed.

The film 7 has a title section at its trailing end and, in order to prevent this being drawn into the winding compartment of the cassette 8, a lock is provided on the casette. When the lock is effective to prevent movement of the film 7 into the winding compartment, the lever 12 takes up its film transport position because this region of the film is arranged to have no perforations 7a in which the lever can be received. However, the winding lock prevents the film being driven so that the motor 1 6 comes to rest, whereby the centrifugal switch 29a opens the switch 20 to deenergise the motor. When the cassette 8 is changed all the components return to the position shown in the drawing.

When there is no cassette 8 in the camera, the lever 9 is urged by the spring 11 against the stop 1 a but, since it is not held by a film 7, the lever 9 is urged by the spring 10 into the cassettereceiving recess of the camera by an amount dependent on the length of the slot 9a. On actuating the shutter release button 2 for demonstration purposes, the camera operates as described above except that the position of the lever 9 remains unaltered, and consequently the levers 12 and 42 can return to their starting positions as soon as the lever 42 is released by the lever 44 at the end of rightward movement of the connecting rod 40.

The camera described above achieves the advantage of incorporating a motorised film transport arrangement while at the same time enabling the external dimensions of the camera to be substantially the same as, or even less than, those of an equivalent camera without a motorised transport arrangement.

Claims (7)

Claims

1. A still photographic camera for use with film of the kind having perforations therein corresponding to the positions of respective exposure frames and contained within a cassette including a storage compartment from which the film can be progressively transported across an exposure window into a winding compartment, the camera including a shutter, an electric motor operable to wind on a film of the kind specified loaded in the camera in use and to prime the shutter, the electric motor being arranged in the camera so that, when looking in the direction of an object to be photographed, the motor is located in front of the region of the camera which, in use, receives the winding compartment of a film cassette, a shutter release member, means for detecting perforations in a film of the kind loaded in the camera in use, and switch means connected in a power supply circuit of the motor and operable, in response to detection by said detecting means of a perforation in a film of the kind specified, to de-energise the motor.

2. A camera as claimed in Claim 1, wherein the electric motor includes a drive pinion which is operable by way of a gear train to drive a take-up spool in the winding compartment of a film cassette loaded in the camera in use, the gear train being composed of generally planar, toothed gear wheels arranged so as to minimise the height of the gear train.

3. A camera as claimed in Claim 2, wherein said detecting means forms part of means for controlling energisation of the electric motor in accordance with priming and release of the shutter, the control means including a plurality of generally flat levers or sliders of overall height less than or equal to the overall height of said gear train and said drive pinion.

4, A camera as claimed in Claim 3, wherein the components of the gear train and the control means are arranged so that collectively they extend mainly in a direction parallel with the film transport direction.

5. A camera as claimed in any preceding Claim, and including at least one electrical battery located adjacent the region of the camera which, in use, receives the storage compartment of a film cassette.

6. A camera as claimed in any preceding Claim, and including two torch batteries located adjacent the region of the camera which, in use, receives the storage compartment of a film cassette and arranged such that they extend generally parallel with the optical axis of the shutter.

7. A still photographic camera as claimed in Claim 1 comprising the combination and arrangement of parts substantially as hereinbefore described with reference to, and as shown in, the accompanying drawing.