US2217405A

US2217405A - Claw film feeding means

Info

Publication number: US2217405A
Application number: US94818A
Authority: US
Inventors: Clinton R Hanna; William O Osbon; Kirk A Oplinger
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1936-08-07
Filing date: 1936-08-07
Publication date: 1940-10-08
Anticipated expiration: 1957-10-08

Description

Patented Oct. 8, 1940 UNITED STATES PATENT OFFICE CLAW FILM FEEDING MEANS Application August 7, 1936, Serial No. 94,818

8 Claims.

An object of our invention is to provide a simply 4constructed intermittent movement of the claw type that shall be operated from a power A shaft which is perpendicular to the plane of the film.

In `accordance with our invention, we have provided an intermittent movement of novel structure. To simplify the special relationship between the picture optical system and the main drive shaft, it is desirable that the film when it is exposed to projecting or photographing light shall -move with its plane in a direction perpendicular to the drive shaft. Any other arrangement wouldrequire that either the drive shaft or the optical system be bent at right angles to its original direction. However, with the drive shaft arranged perpendicular to the film in the picture gate, a problem arises in producing intermittent movement of the film and' this problem has been solved in the past by utilizing at least two peripheral cams. According to our invention, we provide an intermittent movement mechanism in which only a single peripheral cam is utilized. The desired motion of the claw is attained in the coupling means between the claw and the yoke following the peripheral cam.

While our invention is herein shown as specifically applied to a reproducing machine, it may f also be applied with facility to a recording and photographing machine and we contemplate within the scope of our invention any system incorporating its essential elements regardless of whether it is designed for Areproducing and projecting system or for photographing yand recording.

'I'he novel features that we consider characteristic of our invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method o f operation, together with additional objects and advantages thereof will best be understood from the following description of a specic embodiment when read in connection with the accompanying drawing, in which Fig.. 1 is a view in top elevation of a machine incorporating a mechanism according to our in vention.

Fig. 2 is a view in front elevation of an'intermittent movement assembly according to our invention, and

Fig. 3 is a view in end elevation of the intermittent movement assembly.

The apparatus showny in the drawing comprises a box shaped structure I, in the upper portion 3 of which the mechanical elements of the machine are arranged and in the lower portion of which the photo cell and the amplifier are mounted. The latter elements do not concern the present invention and will not be discussed in detail. The box i is provided with a top cover 9 hinged at the back anda cover Il hinged at the center of the front surface and enclosing the upper half of the front surface on which the machine mechanisms are mounted when closed. The covers 9 and Il are customarily closed when the apparatus is in opera.- tion.

The film-advancing mechanisms and the sound and picture take-offs are mounted on a plate 35 extending vertically from the top of the container. The plate 35 svparallel to the front surface 3l of container I and extends from the end 29 substantially to a plane passing through the vertical center line of this surface. It is moreover located approximately one third of the distance between the front surface 31 and the rear surface. The film is advanced through the picture gate 45 by the claw 41 of an intermittent movement mechanism 49 into a second loop. From the second loop it passes over a sound takeoff drum and is held in engagement with the surface of the drum by the action of an idling pressure roller 55. Since it is desirable that the film engage the drum over a considerable angle of its surface, an idler roller 56 is provided above the drum whichproperly defiects the lm. The film Siifpasses from the idler 56 over a second sprocket wheel 51 mounted on the same shaft 59 as the feed sprocket wheel 4i and it is advanced by the former sprocket wheel to the takeup reel.

As the film is pulled by the take-up sprocket wheel 51, it is tensioned and causes the sound take-oi drum over which it is wound to rotate. To vmaintain the speed of the film as it passes over the drum constant, the drum is provided with an yinertial arrangement which tends to smooth out variations in its velocity. The inertial arrangement does not concern the present invention.

The mounting of the mechanical elements of the ymachine is illustrated in detail in Fig. 1. The sprocket wheels 4| and 5l, the picture gate 45, the pressure roller, the drum and the idler 56 are located on one surface ofthe plate 35. The bearings for the sprocket wheel shaft 59 and for the drum shaft 63 are located in the surface 35 and the picture gate 45 and the other elements are supported on brackets mounted on the surface or are fastenedto the surface.

The picture projection lamp 65 is disposed in a separate container 61 of stamped sheet metal located within the container adjacent to and to the left of the surface 35 on which the motion picture mechanisms are mounted. The container 61 is provided with brackets whereby the elements of the picture optical system B9 are carried. The structure and support of the optical system does not concern the present invention and will not be discussed in detail.

In the left hand rear portion of the container 1, the driving motor 11 is mounted. We have found a small fractional horsepower motor to be suitable for driving the apparatus. A fan 13 is mounted on the motor shaft 15'and is located within an enclosure 11, which is in communication with the lamp chamber 61. As the motor shaft 15 rotates, the fan 13 supplies a blast of cooling air to the lamp 65. The air circulates around the lamp 65 and passes out through a grill in the top 9. Theapparatus is thus prevented from becoming overheated.

A helical pinion 81 is mounted on the Ymotor shaft and it, `yin turn, drives a helical gear 83. The gear 83 is integral with the main shaft 85 of the system and the main shaft is accordingly parallel to the plate S5. Near the end of the main shaft 85, a worm 81 is mounted and it drives a worm wheel 89. The worm 81 and the worm wheel 89 provide for rotating the sprocket wheel shaft 5S which is disposed at right angles to the plate. The sprocket wheel shaft 59 also carries a pulley 91 whereby the take-up reel is rotated. The shaft 63 extending from the drum 55 to its associated shell 6| passes through a bearing 93 supported on brackets 95 secured to the end 25 of the container 1 and to the plate 35.

It is in general desirable that the machine be operated at two speeds. Silent pictures are projected at a rate 16 frames per second while talking motion pictures are projected at a rate of 24 frames per second. Accordingly, we provide a governor for operating the machine at either of the speeds.

The governor comprises a plurality of slip rings 91, 99 and 10| mounted to rotate with the main shaft 85. The slip ring 91 on the left is provided with a stem 103 carrying a plurality of fixed contacts 105 and |111. The fixed contacts are normally in engagement with weighted movable contacts 10Q and respectively mounted on springs 113 and 115, respectively, one of which (|13) extends from the slip ring 99 and the other (115) from the slip ring 10|.

The springs 113 and |15 normally exert appreciable force tending to maintain the movable contacts |08 and |11 in engagement with the corresponding fixed contacts 105 and |01. When the shaft rotates at a predetermined speed, the centrifugal force of the weighted movable contacts |09 and overcomes the spring forces and the movable contacts are separated from the fixed contacts and |01. The springs |13 and are so selected that one of the contacts opens when the speed of the shaft 85 rises above the value corresponding to 24 frames per second and the other opens when the speed of the shaft rises above the value corresponding to 16 frames per second.

Which of the contacts |05-1|i9 or 101--111 is to be effective in controlling the speed is determined by a double-throw switch (not shown). One terminal of the switch is connected to a brush |11 in engagement with the slip ring 91 carrying the fixed contacts |05 and |51 and the other terminals of the switch each to a

brush

119 and 12| in engagement with the other slip rings 99 and 10|, respectively. The first-mentioned terminal may be connected at will to either of the last-mentioned terminals. The contacts 1115-109 and 1111--111 are in series circuit with the power supply for the motor 11 and with the terminals of the double throw switch. Accordingly, the motor circuit is closed throvg'h the centrifugal contacts corresponding to the speed desired and the motor 1| is maintained at the desired speed.

The picture gate 45 is mounted on the surface 35 in such manner that the film passes vertically downward across its surface when a. picture is projected. The axis of the projecting optical system 69 is therefore horizontal. The sound impressions are located along one edge of the film which overhangs the inner end of the drum. The sound is reproduced by projecting a beam of light through the over-hanging edge of the nlm. The drum is located at a'greater distance from the supporting/surface 35 than the picture gate 45 and the film in the loop between the picture gate and the drum is slightly skewed to provide for this difference in distance.

Thelintermitt-ent movement 49 is operated by a peripheral cam 131 of the usual heart-shaped type. The film is, in general, advanced at a rate of 24 frames per second and, therefore, the cam 131 rotates at a rate of 24 revolutions per second. Accordingly. the torque required to drive the cam varies with the periodicity of the motion of the cam. Since the varying torque would produce periodic backlash of the driving gears 8| and I3 and an accompanying noise, we have provided for eliminating the eiiect of the varying torque.

In providing the intermittent movement 49, we were confronted with a problem arising from the relative arrangement of the main shaft 85 and the picture gate 45. It will be noted that the main shaft is perpendicular to the picture gate. This condition arises from the structure of the optical system 69 and also from the arrangement of the driving apparatus. To maintain the apparatus compact, we found that the motor 11 should properly be mounted with its shaft in a direction perpendicular to the picture gate 45. To then turn the main shaft 85 of the machine at right angles involves difficulties. Therefore, the direction of the main shaft B5 was maintained parallel to that of `the motor shaft 15. In the same way, we found the bending of the picture optical system 69 undesirable and to conserve space we found it necessary to arrange the picture optical system with its axis parallel to the main shaft.

The cam |31 engages the surfaces of a. cam follower |41 at a plurality of points in the usual manner. As the cam is rotated coaxial with the main shaft 85, it produces movement of the cam follower |41 in a plane parallel to the picture gate 45. It is incapable however of producing motion in a direction perpcndicular'to the picture gate. We were, therefore, confronted with the problem of converting a portion of the cam follower motion into motion in a direction perpendicular to the picture gate. In accordance with the the prior art, this object'has been accomplished by utilizing two or more peripheral cams. We found this procedure prohibitively complicated and accordingly provided a system in which the object is accomplished with a single cam 131 and the coupling means between the cam follower and the claw 41. The structure involved is shown in detail in Figs. 2 and 3.

' The cam follower |41 is constructed of sheet material and the walls |49 thereof which engage the cam are produced by bending the sheet metal at right' angles to the surface of the metal. Near one corner the follower carries a projection |5| which is provided with a ledge turned at right angles whereby it engages a pin |53 in the surface 35. The follower pivots about the pin. The cam follower |41 is in addition provided with a trapezoidal-shaped framework |55 which extends v downward therefrom and carries at its lower end a guiding channel |51. The latter is composed of a small sheet metal strip bent into a C section and secured to a tongue |59 extending at an obtuse angle from the lower end of the frame |55.l Since the guiding member |51 is fastened with its sides perpendicular to the tongue |59, it is at anacute angle to the surface of the follower |41. Since the latter extends horizontally from the'cam |31 and is therefore parallel to the picture gate 45, the guiding member |51 is at an acute angle to the picture gate.

To suppress spring surge arising from higher harmonics of' the reciprocating motion, a strip of felt is inserted in the coil spring |11. The felt operates to damp out any movement of the spring in resonance with the harmonics of the reciprocating motion.

It is to be noted that by reason of the cooperation of the projection |5l, the pin |53 and the spring |11, the cam follower need have only three cam engaging walls |49. The wall in the upper `rtion of the follower |41 as seen in Fig. 2 is provided by bending a strip of metal attached to the main surface through a ledge |18. The strip and ledge are rst bent at right angles to the main surface; then the strip is bent at right angles to the ledge. The edge of the strip is thus separated from the main surface of the follower |41 and operates as a spring when engaging the cam |31. Another cam engaging wall is an extension of a strip bent at right angles to the trapezoid |55 and a further one is a strip bent at right angles along the upper base of the trapezoid. The spring |11 operates to hold the latter surfaces in engagement with the cam |31.

As the cam |31 rotates, the cam follower |41 and with it the guiding channel |51 moves in four directions in a plane parallel to the plane of the fllm 33. As the cam follower moves downwardly or upwardly (in Fig. 1, this is to the right or to the left), the guiding channel |51 carries the ball |13\and the claw frame |6| attached 'thereto with it and the claw frame simply slides along the pin |69 on which it is supported. As the cam follower moves to the right or to the left (in Fig. 1, this is upwardly or downwardly), the guiding channel |51 being at an angle to the gate, urges the ball |13 in a direction towards the gate 45 or away from it, as it moves over the ball and thus causes the clawvframe to pivot about the pin in a. direction towards and away from the film 33. Accordingly, with reference to Fig. l, it will be seen that as the cam |31 rotates in a counter-clockwise direction, the claw 41 is first carri'ed towards the left, that is, upwardly. It is then advanced towards the film by the downward movement of the guiding channel |51 and eventually engages vthe film. Then, `as the cam follower moves toward the right, the claw 41 moves the film 33 towards the right, that is, downwardly and finally as the cam follower moves upward itdisengages the film and is ready for a further cycle.r

Although we have shown and described certain specificv embodiments of our invention, we are fully aware that many modifications thereof are possible. Our invention, therefore, is not to be restricted except insofaras is necessitated by the prior art and by the spirit of the appended claims.

We claim as our invention:

l. Motion picture apparatus comprising means for subjecting a film to radiant energy, a member for engaging said film to produce intermittent motion thereof, an element for transmitting motion to said member, means for moving said element, in a plane substantiailly parallel to the plane of said film, in such manner that at least one point of said element repeatedly tends to trace a rectangular figure, `two of the sides of which are longitudinal of the film and two of the sides of which are transverse thereto,and coupling means betweenk said element and said member, ysaid coupling means including means for `converting the motion of said member transverse to the lm into motion perpendicular thereto whereby said member is moved into and out of engagement with said film,

2. In combination in intermittent vmovement; apparatus an operating member, an element for transmitting motion to said member, means for moving said element in a single plane, at least one of the points of said element tending to trace out a rectangular figure, and coupling means between said element andsaid member including means for converting the movement of said element corresponding to two opposite sides of said rectangular figure into motion of said member perpendicular to said plane.

3. Motion picture apparatus comprising means for subjecting a film to radiant energy, a member for engaging said film to produce intermittent motion thereof, an element for transmitting motion to said member, means for moving said element in a plane substantially parallel to the plane of said film in such manner that at least one point of said element repeatedly tends to trace a rectangular' figure, two of the sides of whichare longitudinal of the 'film and two of the sides of which are transverse thereto and coupling means between said element and'said member, said coupling means including means for converting the motion of said member transverse to the lrn into motion perpendicular thereto whereby said member is moved into and out of engagement with said lm, said converting means including a guide disposed at an angle less than 180 to the plane of said lm and a guide follower.

4. In combination in intermittent movement apparatus an operating member, an element for transmitting motion to said member, means for moving said element in a single plane, at least one of the points of said element tending to trace out a rectangular figure, and coupling means between said element and said member including means for converting the movement of said eiement corresponding to two opposite sides of said rectangular iigure into motion of said member perpendicular to said plane, said converting means including a guide secured to said element with its guiding line at an angle less than 180 to said plane and a guide follower secured to said member.

5. In combination, in intermittent movement apparatus an operating member, means for supporting said member on an axis so that it may slide along said axis and pivot about said axis, a cam of the peripheral heart-shaped type, means for rotating said camfso that its periphery moves in a plane at an angle substantially different from to said axis, a cam-follower engaging said cam and moved as said cam rotates, and connecting means between said cam follower and said member including a pair of elements in engagement with each other, said elements being capable of sliding motion relative to each other at an angle less than to said plane.

6. In combination in intermittent movement apparatus an operating member, means for supporting said member on an axis so that it may slide along said axis and pivot about said axis, a cam of the peripheral heart-shaped type, means for rotating said cam so that its periphery moves in a plane at an angle substantially different from 90 to said axis, a cam-follower engaging said cam and moved as said cam rotates and connecting means between said cam-follower and said member including a guide, capable of permitting sliding motion in a direction at an angle less than 180 to said plane, secured to said cam-follower, and a. guide follower secured to said member and in engagement with said guide.

7. In combination, in intermittent movement apparatus an operating member, means for supporting said member on an axis so that it may slide along said axis and pivot about said axis, a cam of the peripheral heart-shaped type, means for rotating said cam so that its periphery moves in a plane at an angle substantially different from 90 to said axis, a cam-follower engaging said cam and moved as said cam rotates and connecting means between said cam-follower and said member including a tube secured to said cam-follower with its axis at an angle less than 180 to said plane and a pin secured to said member and in longitudinally slidable engagement with said tube.

8. Motion picture apparatus comprising means for subjecting a film to radiant energy, a member for engaging said film for producing intermittent motion thereof, means for supporting said member on a shaft substantially parallel to the plane of said fllm so that it may slide along said shaft and pivot about said shaft, a cam of the peripheral heart-shaped type, means for rotating said cam so that its periphery moves in a plane substantially parallel to the plane of said lm, a cam follower engaging said cam to be moved as said cam rotates, and connecting means between said follower and said member including a tube secured to said follower with its longitudinal axis extending in a plane substantially perpendicular to said shaft and a pin secured to said member and in longitudinally slidable engagement with said tube.

CLINTON R. HANNA. WILLIAM O. OSBON. KIRK A. OPLINGER.