US2166696A - Safety shutter for motion picture projectors - Google Patents

Description

y 1939- H. c. WELLMAN 9 SAFETY SHUTTER FOR MOTION PICTURE PROJECTORS Filed May 11, 1938 Fig.

INVE TOR BY M/ ATTORNEYS Patented July 18, 1939 SAFETY SHUTTER FOR MOTION PICTURE PROJECTORS Howard C. Wellman, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application May 11, 1938, Serial No. 207,337

18 Claims. (Cl. 88-194) The present invention relates to a safety screen for motion picture apparatus, and more particularly to a safety screen which intercepts the light beam in projection types of motion picture apparatus and which is moved out of and into the light beam when surrounding circumstances attain predetermined conditions.

Particularcare must be exercised in projecting a light beam through photographic film which has a cellulosic base, inasmuch as the intensity of the light beam for satisfactory projection of images on the film must be so great that the film is likely to become ignited. This source of danger has been recognized for a considerable time, and many different type of safety shutters have been devised which protect the film when stationary or traveling at low speed, and which are automatically removed from the light beam when the travel of the film is increased to a degree that the film is in no danger of being ignited although. exposed to the direct rays of the light source. The known devices for effecting the movement of such a safety shutter are all quite complicated or subject to failure. One of the major faults of devices of this character is found in the jerky manner in which they either move into or out of their operative positions. Also, in apparatus where the safety shutter is adapted to operate in either a forward or reverse movement of the projector and mechanism, a counter balance construction is used to hold the safety shutter in its normal operative position and such a structure lends itself to an undesirable pendulum action wherein the safety shutter may swing back and forth past the light beam before coming to rest in its operative position to obstruct the same.

The primary objectof the present invention is the provision of a simple but effective safety screen which normally intercepts the light beam of a motion picture apparatus, and which is automatically moved out of said light beam when. the film is moving at or about a predetermined speed.

Another object is to provide a safety screen which is operable during either a forward or reverse movement of the projecting mechanism.

And still another object is the provision of a safety screen which is normally held in its operative position by a gravity actuated means which is so arranged as to eliminate the pendulum action common to similar structures using a gravity actuated means for the same purpose.

And another object is to provide a gravity actu ated means for the purpose set forth which is so arranged as to limit the movement of the safety screen away from its operative position.

A further object is the provision of a gravity actuated means which is simple in construction, effective in operation, and adapted for use in como bination with known safety shutter constructions.

And yet another object is to prov =1, a safety means which prevents the heat rays from burning the film, but may permit sufficient light rays to pass for the projection of still pictures without 10 damaging the film.

The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and 15 its methods of operation, together with additional objects and advantages thereof, will best be understood from the following description of specific embodiments when read in connection with the accompanying drawing in which, 20

Fig. l is a plan view of the safety screen according to the present invention, and showing its location in the motion picture projector, portions of the projector casing being cross-sectioned for clear illustration of the safety screen, 5

Fig. 2 is a fragmentary section taken through the projector casing and showing in elevation the safety screen moved to its inoperative position relative to the aperture in the casing,

Fig. 3 is a perspective view of the safety screen according to the invention,

Fig. 4 is a section taken on line 4- of Fig. 2,

Fig. 5 is a sectional detail showing the manner of mounting the gravity actuating in the projection apparatus, and

Fig. 6 is a view similar to 2 but showing another embodiment of the invention.

Like reference characters refer to corresponding parts throughout the drawing.

In the illustrated embodiment, the safety screen is shown in cooperation with the known. elements of a motion picture projector, howev it is to be understood that such a safety screen may be used under any circumstances which require the projection. of a stationary and slow moving film from. the total direct rays of the light source.

The present invention is an improvement the safety shutter mechanism disclosed in my co pending patent application, Serial Number 138,627, filed April 23, 1937, and is shown in this application in combination with said, shutter mechanism, it being of course substituted for the cantilever spring shown in the above noted application.

The projector casing indicated broadly as H) is made up of two parts, a mechanism chamber II and a lamphouse l2 within which a light source such as an incandescent lamp |3 is mounted. A shielding plate I4 is fixed to rib l5 on the wall |6 to prevent the exit of extraneous light from the lamphouse I2. A condenser lens assembly I1 is located in alignment with suitable apertures l8 and IS in the shielding plate I4 and the wall iii of the projector housing respectively, and in alignment with each of these apertures is the customary objective tube 20. The shutter shaft 2| journaled in the gear housing 22 in the mechanism chamber extends into the lamphouse l2, and may be driven in either direction of rotation through the gears 23 and 24 from the motor shaft 25. The end of the shutter shaft 2| extending into the lamphouse |2 constitutes a reduced threaded end 26 onto which the nut member 21 is screwed to hold the disk shutter 28 against the washer 29, see Fig. 4. Fixed to that portion of the shutter shaft between the wall l6 and the shielding plate M is an eccentric 36 which is adapted to engage an apertured film claw 3| and drive said claw in the customary manner to feed the film strip F past the aperture Hi.

The elements thus far described are well known in the motion picture art and form no part of the present invention except in so far as they enter into combination with the parts of the apparatus to be described hereinafter.

A hollow cylindrical bearing member 4| is slid onto the nut member 21 to loosely engage the shoulder 42 thereof so as to be movable axially of and rotatable with respect to the nut member. One end of the bearing member 4| is provided with a circular flange 45 which loosely engages the reduced end 35 of the nut member 21. A coil spring 46 surrounding the nut member 2! and being enclosed by the bearing member 4| has one end engaging the shoulder 42 on the nut member 21 while the other engages the circular flange 45 on the bearing member whereby the bearing member is normally forced axially of the nut member and away from the disk shutter 28.

The reduced end 35 of the nut member'is provided with an end slot 35' within which a pair of bcllcranks 36 and 31 are pivoted. For this purpose a pin 38 passes through the end slot 35 and through intermediate portions of the bellcranks 36 and 31 so that the same are mounted to pivot about a common axis. The bellcranks 36 and 3'! each have a weight 39 located at one end of one arm, and have a cam portion 40 on the other arm. The cam portions 40 engage the flange on the bearingmember 4|, and serve to hold said bearing member on the nut member against the action of the coil spring 46.

The screen member comprises a central portion 56 which has a plurality of integral fingers,

5|, which may or may notbe resilient, and which are offset from the plane of the portion 56. To one side of the central portion is located a ring member to which a safety screen 56 may be fastened by tabs 51. This safety screen may consist of a medium for reducing heat rays such as copper or other heat dissipating wire screens, gold plated glass, mica, slotted metal, or any well-known heat retarding material. The materials above-mentioned are adapted to pass certain light rays for projecting stills, but it is obvious that if desired an opaque screen could be mounted in the ring 55.

The screen member is mounted in the projector so that the hole 58 in the central portion 56 thereof loosely encircles the bearing member 4| and is located thereon between the shoulders 59 and 66 to move axially of the nut member with the bearing member 4|, see Fig. 4. When the screen member is thus mounted on the bearing member 4|, the safety screen 56 is counter-balanced by the disk 6| mounted at the opposite side of the central portion 56 to that on which the safety screen is mounted. The disk 6| and the ring member 55 of the screen member each include apertured projections 62 and 63 respectively which extend radially from the periphery of said members for the purpose hereinafter described.

The bearing member 4| may be held on the nut member 21 by the bellcranks 36 and 31 so that the flanged fingers 5| of the screen member will be held in constant frictional engagement with the disk shutter 28. If this condition exists, the spring fingers 5| should be resilient so that as bearing member 4| is moved toward the disk shutter 28 by outward movement of the bellcranks 36 and 31, the normal frictional engagement between the fingers 5| and the disk shutter 28 will be increased to move the screen member to the position shown in Fig. 2. On the other hand, bearing member 4| may be held on the nut member by the bellcranks 36 and 3'! so that normally the coil spring 46 may move the bearing member away from the shutter 28 so that the fingers 5| do not normally engage the shutter disk 2?, see Fig. l, in which case the fingers may be more or less rigid.

Fixed to the shielding plate I4 in any suitable manner is a U-shaped bracket 76, the free end of which comprises two spaced fingers H and 12 to which are attached headed pivot studs 13 and 14, see Figs. 2 and 5. The studs 13 and '14 are mounted on the bracket 10 so that they will be positioned substantially in the plane of the screen member to allow the gravity actuating means mounted on the studs, as hereinafter described, to effectively control the movement of said screen member, and it is pointed out that should the position of the shielding plate M or any other stationary part of the apparatus be sufficiently near to the plane of the screen member that the pivot studs could be mounted directly thereon without benefit of a bracket such as bracket Ill shown.

In the preferred embodiment, as shown in Fig.

.2, the gravity actuating means comprises a weight 15 one side 16 of which is provided with an arcuate slot IT, and the other side 18 of which is provided with an arcuate slot 19. For the purpose of reducing the mass of the weight 15 without spoiling its effectiveness, the Weight is cut away as shown at 89 leaving the identical sides 16 and 18 connected by the cross member 8|. The weight 15 is mounted on the pivot studs '13 and 14 so that the arcuate slot 11 in side I6 engages stud l3, and the arcuate slot 79 in side 18 engages stud 14. The slots are made slightly greater in width than the diameter of the studs so that the weight 15 is free to move relative thereto due to the effect of gravity. Referring to Fig. 2 it will be noticed that in its normal position the weight l5 will drop downwardly due to the effect of gravity to a position wherein the studs 73 and 14 are at the upper end of each of the slots 1! and 19, and the cross member 8! is horizontal.

Extending from the sides 16 and 18 are the arms 82 and 82 which are each provided with apertures 83 and 83' respectively. These apertures are countersunk from opposite sides of the arm,

as clearly shown and for the purpose which will be obvious from the following description of the connection between the screen member and the weight 15. Wire links 84 and 85, equal in length, have one end hooked through the apertured projections 62 and 63 on the disk 6| and ring member 55 respectively, and the other end of each of these wire links loosely extends through the apertures 83 and 83' in the arms 82 and 82' and are provided with loops 86 and 81 which prevent the links from being pulled through said apertures. These wire links are of such a length that when the weight 15 is in its normal position, see dotted position Fig. 2, the screen member is moved to and held in its covering position relative to the apertures l8 and [9 of the shielding plate 14 and the projector casing respectively.

When the shutter shaft has attained a predetermined speed of rotation the friction set up between the shutter 28 and the screen member will be sufficient to move the screen member to the position shown in Fig. 2 against the resistance of the weight 15, and the weight will be moved to the position shown in full lines. It is to be understood that although I have shown the screen member rotated in one direction relative to the apertures, the shutter is capable of rotation in either direction, said. direction depending of course upon whether the apparatus is run in forward or reverse. In moving to the position shown, the weight 15 is pivoted about the stud l3 and the side 18 thereof is raised until the stud 14 meets with the lower end of the slot 19 whereby movement of the weight and the screen member in'this direction is positively limited. The length of the slot 19 is such as to allow 'just enough movement to the weight and screen member to permit of the ring member 55 of the screen member being moved to uncover the apertures 18 and I9. It will be noted that in this position of the screen member the diskfil is moved toward the side 16 of the weight, and to permit this, the wire link 8 slides through the aperture 83 in the arm 82, the countersunk portions thereof allowing the links to assume the angle necessary, as shown in Fig. 2. When the speed of the apparatus falls below the predetermined value, the side 18 of the weight 15 falls due to gravity, and pulls the screen member back to its covering position relative to the apertures l8 and I9. In returning to its normal position the weight 15 is abruptly stopped due to the stud '14 coming into engagement with the end of the slot 19 in the side 18 thereof, and by virtue of this arrangement the undesirable pendulum action of the shutter, common to known safety shutter mechanisms having gravity actuated means for returning the screen to its operative position, is eliminated. It will be readily understood that if the apparatus is operated in the opposite direction to that indicated, the weight 15 will be pivoted about stud 14 and the side .'5 of the weight will oppose movement of the screen member and will be raised.

In Fig. 6 I have illustrated another embodiment of the present invention wherein the gravity actuated means comprises two individual weights instead of one arranged in the manner described in connection with the preferred embodiment. In this embodiment the pivot studs 13 and M are fixed to a bracket in a manner identical with that described in connection with the preferred embodiment with the exception that the studs are spaced further apart relative to one another to be located substantially in vertical alignment belowthe projections 62 and 63 on the low speed the disk BI and the ring member 55 of the screen member. Movably mounted on each of the studs 13' and HV in slotted engagement therewith are slotted weights 16' and 18. The slots 11 and 19 in these weights may be straight instead of arouate because the weights in this arrangement move substantially in a vertical path. The weights l6 and 18' are provided with an overhanging portion 90 and 90' which are provided with apertures 9| and 9|. These apertures are countersunk from opposite sides of the overhanging portions in the manner and for the purpose described in connection with the preferred embodiment. The weight 76' is connected with the disk 6| by a wire link 84' loosely hooked at one end to the projection 62 on the disk 6|, the other end loosely extending through the aperture 9| and being provided with a loop 85' to prevent its being pulled through said aperture. The weight 18' is connected in a similar manner to the ring member 55 by a wire link 85'. When the screen member is rotated due to the shutter shaft 2| having obtained a predetermined speed, the screen member, in one direction of'rotation, will be rotated to the position shown. In rotating to this position the screen member will be opposed by a weight 18, and its amount of rotation will be positively limited when the stud M comes to the end of the slot 19 therein. During movement of the screen member in this direction the weight 16 remains stationary in its normal position wherein the stud 13' is at the upper end of the slot 11 therein, and the wire link 84' slides through the aperture 9| in the overhanging portion 90, in the manner shown in Fig. 6. It will be readily understood that rotation of the screen member in the opposite direction will be opposed by weight 16, or the relation of the several parts shown in Fig. 6 will be reversed.

Referring to Fig. 6 wherein the gravity actuated means being individual weights is shown, it will be obvious that such an arrangement using but a single'weight could be readily adapted for use with a projection apparatus capable of operation only in one direction, without going beyond the scope of the present invention. In-such a case the single weight would be situated as is weight 18' in Fig. 6, and would serve to resist-rotation of the screen member in the direction shown and would also serve to positively limit the extent to which the screen member could move. Since an individual weight such as 18' would be positively stopped in returning to its normal position by engagement of the stud coming to the end of the slot in the weight, a pendulum action of the weight and screen would be eliminated.

The eration of the safety screen according to the plemrred embodiment of the present invention will he describec hereinafter:

When the motion picture apparatus is operated, the shutter shaft iii may rotate in either directicn depending upon the condition of projection required. The disk shutter 28 and the belloranks (-36 and 3'5 ail also rotated, but at frictional engagement between the fingers i and the surfs. of the shutter 28, if the bearing 4% is mounted on the nut member 2'! so that normal frictional engagement exists here, is not sufficient to overcome the action of the weight it and the screen member remains in a normal or protecting position. the rotational speed of the shutter shaft 2! is increased, the weights 39 on the bell-cranks 36 and 3'! fly apart by virtue of the centrifugal forces created therein. and take the position shown in Fig. 4. The bell- cranks 36 and 31 rotate upon pin -38 so that the cam portions 40 thereof move the bearing member 4| axially along the nut member 2'! against the action of the coil spring alone, if the fingers iii are normally out of frictional engagement with each other, or against the combined action of the coil spring 46 and the resilient fingers if said fingers are normally infrictional engagement with said shutter 28. This axial movement of the bearing member 4| moves the screen member to increase the frictional engagement between the fingers 5| and the shutter 28, if a normal engagement exists, or, if no normal engagement exists, moves the fingers into frictional engagement until an engagement is obtained having such a value as to overcome the resistance of the weight 15, whereupon the side E3 of said weight is raised to the position shown. The screen member is then moved in the direction of the shutter rotation, illustrated in Fig. 2 as counterclockwise, until the pivot stud 14 engages the end of the slot 19 wherein the shutter screen is moved out of the light beam between the condenser lens assembly H and the aligned apertures H5 and IS in the shielding plate l4 and projection casing IE5 respectively. Conversely, when the shutter shaft 2! becomes stationary or falls below a predetermined speed the coil spring 46, or if the fingers 5! are resilient, the combined action of the coil spring 66 and the fingers overcome the action of the weights 39, which are brought together, and the bearing member and the screen member are moved axially of the nut member 2'! so that the frictional engagement between the fingers 5i and the shutter 28 is decreased or relieved, as the case may be, so that the weight i5 pivoting about stud i3 predominates and falls to its normal position to move the safety screen into normal or covering position with respect to the apertures l8 and I9. It should'be noticed that the weight to, as arranged in the apparatus, will positively limit the movement of the screen member in one direction and return the same rapidly to its normal position without a pendulum action, thus overcoming two difficulties found in known safety screens using a gravity actuated means for returning them to'their normal positions.

Although I have shown and described certain specific embodiments of my invention, I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except in so far as is necessitated by the prior art and by the spirit of the appended claims.

Having thus described my invention what I claim is new and desire to secure by Letters Patent of the United States is:

1. In a motion picture apparatus having a projection aperture, the combination with a driven shaft adapted to be rotated in either direction for forward or reverse operation of said apparatus, a safety shutter rotatably mounted on. said apparatus and covering said aperture, and an actuating means operatively connected between said shaft and said safety shutter and adapted upon said shaft attaining a predetermined speed to cause movement of said shutter away from said aperture in a direction corresponding to the direction of rotation of said shaft, of a gravity actuated means mo-vably mounted on said apparatus and connected to said shutter for normally holding said shutter in covering position relative to said aperture, and means on said apparatus for guiding the movement of said gravity actuated means and adapted to eliminate a pendulum action of said gravity actuated means in returning said shutter to its covering position relative to said aperture.

2. In a motion picture apparatus having a projection aperture, the combination with a driven shaft adapted to be rotated in either direction for forward or reverse operation of said apparatus, a safety shutter rotatably mounted on said apparatus and covering said aperture, and an actuating means operatively connected between said shaft and said safety shutter and adapted upon said shaft attaining a predetermined speed to cause movement of said shutter away from said aperture in a direction corresponding to the direction of rotation of said shaft, of a gravity actuated means connected to said shutter and opposing movement thereof from said aperture by said actuating means, said gravity actuated means movably mounted on a stationary part of the projection apparatus so as to positively limit the movement of said shutter in either direction.

3. In a motion picture apparatus having a projection aperture, the combination with a driven shaft adapted to be rotated in either direction for forward or reverse operation of said appara tus, a safety shutter rotatably mounted on said apparatus and covering said aperture, and an actuating means operatively connected between said shaft and said safety shutter and adapted upon said shaft attaining a predetermined speed to cause movement of said shutter away from said aperture in a direction corresponding to the direction of rotation of said shaft, of a weight connected to said shutter to resist rotation thereof in either direction, said weight movably mounted on a stationary part of the projection apparatus so as to eliminate a pendulum action thereof in returning the shutter to its covering position.

4. In a motion picture apparatus having a projection aperture, the combination with a driven shaft adapted to be rotated in either direction for forward or reverse operation of said apparatus, a safety shutter rotatably mounted on said apparatus and covering said aperture, and an actuating means operatively connected between said shaft and said safety shutter and adapted upon said shaft attaining apredeterrnined speed to cause movement of said shutter away from said aperture in a direction corresponding to the direction of rotation of said shaft, a pair of spaced stationary pins mounted in said apparatus, of a gravity actuated means associated with said shutter to resist rotation of the same in either direction and arranged so that a pendu lum action in returning said shutter to its covering position relative to said aperture is eliminated, said means including a slotted weight in pin and slot engagement with said pins so that in its normal position it is held against movement induced by gravity but is capable of a limited movement in opposition to the effect of gravity, and means connecting said weight to the shutter, whereby rotation of the shutter'in either direction is resisted and limited by said weight.

5. In a motion picture apparatus having a projection aperture, the combination with a driven shaft adapted to be rotated in either direction for forward or reverse operation of said apparatus, a safety shutter rotatably mounted on said apparatus and covering said aperture, and an actuating means operatively connected between said shaft and said safety shutter and adapted upon said shaft attaining a predetermined'speed to cause movement of said shutter away from said aperture in asdirection corresponding to thedirection of rotation of said shaft, a'pair of spaced stationary pins mounted in said apparatus, of a gravity actuated means associated with said shutter to resist rotation of the same in either direction and arranged so that a pendulum action in returning said shutter to its covering position relative to said aperture is eliminated, said means including a slotted weight in, pin and slot engagement with said pins so that in its normal position it is held against movement induced by gravity but is capable of a limited movement in opposition to the effect of gravity, and a pair of spaced links connecting'said weight to the shutter, whereby rotation of the shutter in either direction is resisted and limited by said weight.

6.v In a. motion picture apparatus having a projection aperture, the combination with a driven shaft adapted to be rotated in either direction for forward or reverse operation of said apparatus, a safety shutter rotatably mounted on saidapparatus and covering said aperture, and an actuating means operatively connected between said shaft and said safety shutter and adapted upon said shaft attaining a predetermined speed to cause movement of said shutter away from said aperture in a direction corresponding to, the direction of rotation of said shaft, apair of spaced stationary pins mounted in said apparatus, of a gravity actuated means associated with said shutter to resist rotation of the same in either direction and arranged so that apendulum action in returning said shutter to its covering position relative to said aperture is eliminated, said. means including a pair of individual slotted weights, one of which is in pin and slot. engagement with each of said pins so that in their normal position each is held against movement induced by gravity but is capable of a limited movement in opposition to the effect of gravity, a link connecting each weight to the shutter, whereby the weights in their normal position. hold the shutter in covering relation with saidaperture, and one weight resists but permits a limited rotation of the shutter in one direction, while the other weight resists but permits a limited rotation of the shutter in the other direction.

'7. In a motion picture apparatus having a projection. aperture, the combination with a driven shaft, a safety shutter member rotatably mounted on said: apparatus and arranged to cover said aperture, and an actuating means operatively connected between said shaft and said safety shutter member and adapted upon said shaft attaining a predetermined speed to cause movement of said shutter member away from said aperture in a. direction corresponding to the direction of. rotation of the shaft, of a gravity actuatedmeans movably mounted on a stationary 'partof said apparatus to be capable of limited movement in opposition to the effect of gravity but. prevented against movement due to gravity, and means connecting said gravity actuated means and said shutter whereby rotation of the shutter is resisted and limited by said gravity actuated means.

8. In anmotion picture apparatus having a projection aperture, the combination with a driven shaft, a safety shutter member rotatably mounted on said apparatus and arranged to cover said aperture, and an actuating means operatively connected between said shaft and said safety shutter member and adapted upon said shaft attaining a predetermined speed to cause movement of said shutter member away from said aperture in a direction corresponding to the direction of rotation of the shaft, a stationary pin mounted in said apparatus, of a gravity actuated means associated with said safety shutter to resist rotation of the same, and arranged so that a pendulum action in returning said shutter to its covering position relative to said aperture is eliminated, said means including a slotted weight in pin and slot engagement with said stationary pin so that in its normal position it is held against movement induced by gravity but is capable of a limited movement in opposition to the effect of gravity, and a link connecting said shutter and weight whereby rotation of the shutresisted andlimited by-said weight.

9. In a reversible motion picture apparatus having an aperture, the combination with a driven shaft adapted to be rotated in either direction, a shutter fixed to said shaft to rotate therewith, a screen member rotatable with respect to said shaft and axially movable therealong with respect to said shutter, a centrifugal means adapted'upon attaining a predetermined speed directly to remove said screen member axially of the shaft and into frictional engagement with the shutter so that the screen member is moved to uncover the aperture, of a weight connected to said screen member to resist rotation thereof in either direction, said weight movably mounted on a stationary part of the preiection apparatus so as to eliminate a pendulum action thereof in returning the shutter to its covering position.

10. In a reversible motion picture apparatus having an aperture, the combination with a driven shaft adapted to be rotated in either direction, a shutter fixed to saidshaft to rotate therewith, a screen member rotatably mounted with respect to said shaft and axially movable therealong relative to said shutter, and including integral resilient means in direct frictional engagement with said shutter, gravity actuated means movably mounted on said apparatus and connected to said screen member to resist rotation thereof in either direction from a covering position with respect to said aperture, and means on said apparatus for guiding the movement of said gravity actuated means arranged on said projection apparatus and. adapted to eliminate a pendulum action of said gravity actuated means in returning the shutter to its covering position, and a centrifugal means adapted upon attaining a predetermined speed directly to move said screen member axially of the shaft to move said screen member against the action of said integral resilient means to increase the frictional engagement between said shutter and said screen member so that the screen is moved against the resistance of the gravity actuated means to uncover said aperture.

11. In a reversible motion picture apparatus having an aperture, the combination with a driven shaft adapted to be rotated in either direction, a shutter fixed to said shaft to rotate therewith, a screen member rotatably mounted with respect to said shaft and axially movable therealong relative to said shutter, and including resilient means in direct frictional engagement with said shutter, gravity actuated means movably mounted on said apparatus and connected to said screen member to resist rotation thereof in either direction from a covering position with respect to said aperture, and means on said apparatus fer guiding the movement of said gravity actuated means arranged on said projection apparatus and adapted to eliminate a pendulum action of said gravity actuated means in returning the shutter to its covering position, and a centrifugal means including a pair of bell cranks intermediately pivoted about a common axis, each bell crank having a weighted arm and a cam portion on the other arm adapted to engage and move said screen member upon rotation of said bell cranks, whereby said screen is moved against the resistance of the gravity actuated means to uncover said aperture,

12. In a reversible motion picture apparatus having an aperture, the combination with a driven shaft adapted to be rotated in either direction, a screen member rotatably mounted with respect to said shaft and axially movable therealong relative to said shutter, a centrifugal means adapted upon attaining a predetermined speed directly to move said screen member axially of the shaft and into frictional engagement with the shutter whereby the screen member is moved to uncover said aperture, of a gravity actuated means associated with said screen member to resist rota-- tion of said screen member in either direction,

and arranged so that a pendulum action is eliminated in returning said screen member to its covering position relative to said aperture, said gravity actuated means including a weight movably mounted on a stationary part of the projection apparatus so that in its normal position it is held against movement induced by the effect of ravity but is capable of movement in opposition to the effect of gravity,and means connecting said weight and said screen member whereby the weight in its normal position holds the screen member in its covering position relative to said aperture and resists movement of said screen member from its covering position.

13. In a reversible motion picture apparatus having an aperture, the combination with a driven shaft adapted to be rotated in either direction, a screen member rotatably mounted with respect to said shaft and axially movable therealong relative to said shutter, a centrifugal means adapted upon attaining a predetermined speed directly to move said screen member axially of the shaft and into frictional engagement with the shutter whereby the screen member is moved to uncover said aperture, of a gravity actuated means associated with said screen member to resist rotation of said screen member in either direction, and arranged so that a pendulum action is eliminated in returning said screen member to its covering position relative to said aperture, said gravityactuated means including a weight movably mounted on the projection apparatus so that in its normal position it is held against movement induced by the effect of gravity but is capable of movement in opposition to the effect of gravity, means connecting said weight and screen member whereby the weight in its normal position holds the screen member in its covering position relative to said aperture and resists movement of said screen member from its covering position, and means on said apparatus adapted to be engaged by said weight for limiting its movement in a direction in opposition to the eifect of gravity whereby movement of the screen member in either direction is positively limited.

14. In a reversible motion picture apparatus having an aperture, the combination with a driven shaft adapted to be rotated in either direction, a shutter fixed to said shaft to rotate therewith,

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a screen member rotatable with respect to said shaft and axially movable therealong with respect to said shutter, a centrifugal means adapted upon attaining a predetermined speed directly to remove said screen member axially of the shaft and into frictional engagement with the shutter so that the screen member is moved to uncover the aperture, a stationary member mounted in said projection apparatus, means associated with said screen member to resist rotation of the same in either direction, and arranged so that' a pendulum action in returning said screen member to its covering position relative to said aperture is eliminated, said means comprising a Weight pivotally mounted on said stationary member so that in its normal position it is held against movement induced by the effect of gravity but is capable of a limited movement in opposition to the effect of gravity, and means connecting said weight and said screen member, whereby the weight in its normal position holds the screen member in its covering position relative to said aperture and resists movement of said screen member from its covering position.

15. In a reversible motion picture apparatus having an aperture, the combination with a driven shaft adapted to be rotated in either direction, a shutter fixed to said shaft to rotate therewith, a screen member rotatable with respect to said shaft and axially movable therealong with respect to said shutter, a centrifugal means adapted upon attaining a predetermined speed direct- 1y to remove said screen member axially of the shaft and into frictional engagement with the shutter so that the screen member is moved to uncover the aperture, a pair of spaced stationary pins mounted in said projection apparatus, means associated with said screen member to resist rotation of the same in either direction, and arranged so that a pendulum action in returning said screen member to its covering position relative to said aperture is eliminated, said means comprising a slotted weight in pin and slot engagement with said pins so that in its normal position it is held against movement induced by gravity but is capable of movement in opposition to the effect of gravity, and means connecting said weight and said screen member,

whereby the weight in its normal position holds the screen member in and resists movement thereof from its covering position relative to said aperture, and serves to positively limit the movement of the screen member in either direction.

16. In a reversible motion picture apparatus having an aperture, the combination with a driven shaft adapted to be rotated in either direction, a shutter fixed to said shaft to rotate therewith, a screen member rotatable with respect to said shaft and axially movable therealong with respect to said shutter, a centrifugal means adapted upon attaining a predetermined speed directly to remove said screen member axially of the shaft and into frictional engagement with the shutter so that the screen member is moved to uncover the aperture, a pair of spaced stationary pins mounted in said projection apparatus, a gravity actuated means associated with said screen member to resist rotation of the same in either direction, and arranged so that a pendulum action in returning said screen member to its covering position relative to said aperture is eliminated, said means comprising a pair of slotted weights, one of which is in pin and slot engagement with each of said stationary pins 75,

so that in their normal position each is held against movement induced by gravity but is capable of movement in opposition to the effect of gravity, and means connecting said weights individually to said screen member, whereby the weights in their normal position hold the screen member in covering relation with said aperture, and one weight resists rotation of the screen member in one direction, while the other weight resists rotation of the screen member in the other direction.

17. In a reversible motion picture apparatus having an aperture, the combination with a driven shaft adapted to be rotated in either direction, a shutter fixed to said shaft to rotate therewith, a screen member rotatable with respect to said shaft and axially movable therealong with respect to said shutter, a centrifugal means adapted upon attaining a predetermined speed directly to remove said screen member axially of the shaft and into frictional engagement with the shutter so that the screen member is moved to uncover the aperture, means associated with said screen member to resist rotation of the same in either direction, and arranged so that a pendulum action in returning said screen member to its covering position relative to said aperture is eliminated, said means comprising a pair of individual weights, each movably mounted on the projection apparatus so that in their normal position they are held against movement induced by gravity, but are capable of a limited movement in opposition to the effect of gravity, and means connecting each of said weights to the screen member, whereby said weights in their normal position hold the screen member in covering position relative to said aperture while each weight serves to resist rotation of said screen member in one direction.

18. In a reversible motion picture apparatus having an aperture, the combination with a driven shaft adapted to be rotated in either direction, a shutter fixed to said shaft to rotate therewith, of a screen member rotatably mounted with respect to said shaft and axially movable therealong relative to said shutter, and including fingers integral therewith and offset from the plane thereof to frictionally engage the disc shutter, gravity actuated means connected to said screen member for normally holding said screen member in covering relation with respect to said aperture, and arranged on said projection apparatus to resist but permit a limited rotation of the screen member in either direction and so that a pendulum action thereof in returning the screen member to its covering position is eliminated, a coiled spring surrounding said shaft and normally acting to force said screen member away from said shutter, and a centrifugal means adapted upon attaining a predetermined speed directly to move said screen member axially of the shaft against the combined action of the coiled spring and the integral resilient fingers to increase the frictional engagement between said shutter and said screen so that the screen is moved to uncover said aperture.

HOWARD C. WELIMAN.

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