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Publication numberUS1350548 A
Publication typeGrant
Publication dateAug 24, 1920
Filing dateDec 11, 1918
Priority dateMar 1, 1918
Also published asUS1359579, US1361144
Publication numberUS 1350548 A, US 1350548A, US-A-1350548, US1350548 A, US1350548A
InventorsDarby John
Original AssigneeEdwin F Flindell
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Film-gate and tension means for motion-picture machines
US 1350548 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)






Specification of Letters Iatent.

Patented Aug. 24, 1920.

Original application `led Iaroh 1, 1918, Serial N. 219,752. Divided and this` application iileii December 11, 191B. Serial No. 266,250.

To all'whom it may concern."

Be it known that I, JOHN DARBY, a citizen of the United States, residing at Summit, in

the county of Union and State of New Jersey, have invented certain new and useful Improvements in Film-Gates and Tension Means for Motion-Picture Machines, of whichy the following is a specification.

rEhe invention relates to film gate mechanism for motion picture machines, and more especially to the means for maintaining the film flat against the aperture plate during the projection of a picture and to release the tension on the iilm strip during its movement to bring the next succeeding picture into frame with the aperture.

The objects of the invention are to provide means for intermittently applying and relieving tension to the film strip which will be instantaneous and noiseless in action and which will' eliminate the wear of moving parts.

These and other objects. and advantages will be set forth in part hereinafter and in part will be obvious herefrom, such objects and advantages being obtained by the instrumentalities pointed out in the accompanying claims.

The invention consists 1n the novel parts, construction, arrangements, combinations andl improvements herein shown and described.

This case is a division of my copending application, Serial No. 219,752, filed March 1, 1918.

Of the drawings:

Figure 1 is an elevation partly in section,

i showing the aperture plate and tension means together with other parts andthe means for automatically applying and relieving the tension to and from the film strip.

Fig. 2. is a section on line A B of Fig. 1.

Fig. 3. is a detail view of vthe 'tension frame.

As embodied in the construction disclosed, a plate or member.` 94, forming a part of or being attached to the frame of a motion icture machine, is provided with two gui ing strips 95, 95 which form a channel for the film strip X and a housing for the aperture plate 14. A gate 96 hinged to member 94 at 97 supports the lamp house 28 and forms a closure for the channel in member 94. Movably supported in gate 96 isa rectangular frame member, consisting of an upper cross bar 98 and a lower cross bar 99 which support between their ends the vertical members 100 and 101. Said vertical membersy are so disposed as to bear, when forced inwardly, on the vertical edges of the fihn strip X andpress it against the aperture plate 14.

Pins 102 and 103 Secured in cross bars 98 and 99, respectively, pass through apertures in ate 96 and terminate in heads 104 and 105.

oused in recesses 106 and 107 of gate 96 are compression springs 108 and 109 embracing the pins 102 and 103 and reacting between the inner faces of recesses 106 and 107 and the outer faces of bars 98 and 99, tending normally to press the vertical members 100 and 101 of the tension frame against the film stri X and maintain said strip in contact wit the aperture plate.

Supported on gate 96 by suitable brackets are two magnets 110 and 111 so disposed as' to have their cores, when energized, attract as armatures the heads 104 and 105 of pins 102 and 103. Means are provided to prevent the armaturesand the cores of the magnets from making metal contact, such for example, as by regulating the tension of springs 108 and 109, or by interposing some non-magnetic cushion, such as rubber or cork between said armatures and said magnet cores; thus eliminating all noise in the operation of the tension device.

Means are provided to intermittently move the film stri X to bring the next succeeding picture o said strip in frame with the aperture 14 of the plate 14 and as shown is comprised of the usual sprocket roller 15 on shaft 33 which may be driven by any suitable mechanism in the well known manner.

Means are provided for exciting the magnets 110 and 111 in time with the movement of film strip X to relieve the tension on said springs 108 and 109 tend always to. create a pressure of the vertical members or shoes 100 and 101 against the iilm strip X to press it fiat and in close contact with the aperture` plate 1&1 While said strip is at rest or during the period ot projection; and that the commutator 112 is so timed as to complete the electric circuit through, and energize the magnets 110 and 111 just before the intermittent sprocket 15 moves to draw down the next succeedingpicture of the iim strip.

The energizing oi magnets 110 and 111 causes them to attract the heads 101 and 105 of pins 102 and 103 and to withdraw the tension frame against the action oi springs 108 andl 109. and `relieve the pressure of shoes 100 and 101 from the film strip. rlihe bridging piece 113 of commutator 112 is oit such a width as to keep the magnets 110 and 111 energized during the full movement oit the ilm strip and to break the circuit through said magnets and release thev ten sion trame as soon as movement of iilm strip ceases.

lit will be evident trom the foregoing,uthat l 1. lin a motion picture projecting machine,

an intermittent'tension device for the nim nemen-e strip, consisting ot two vertical membersconnected by two cross members, pms 1n said -vice and electromagnets to act upon said pins to move said tension device against the pressure of said springs.

3. lin a motion picture projecting machine,

an intermittent tension device for the lm strip, consisting ot two vertical members connected by two cross members, pins in said cross members, tension springs surrounding said pins, a film gate supporting said tension device and housing said pins and, said.

springs and electromagnets to act upon said pins to move said tension device against the tension ot said springs. y

a. 1n a motion picture projecting machine,

an intermittent tension device tor the nlm' strip, consisting of two vertical members connected by two cross members, pins in said cross members, tensionsprings surrounding said pins, a nlm gate supporting said tension device and housing said pins and said springs, electromagnets carried by said gate and acting upon said pins to move said tension -device against the pressure of said springs and a contator to energize said magnets.

1in testimony whereof, li have signed my name to this specication, in the presence of two subscribing witnesses.


Witnesses @Hannes C. Bursar, 1E.. S. Eormnn'r.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2431681 *Jun 23, 1945Dec 2, 1947Argus IncMovable tension shoe
US2534083 *Apr 18, 1946Dec 12, 1950Bradfield And Bidwell IncProjector
US2712770 *Sep 25, 1951Jul 12, 1955BolseyFilm guiding and exposure arrangement
US4227783 *Jul 27, 1978Oct 14, 1980Karl VockenhuberDevice for stopping or fixing moving or mobile components
US4744651 *Feb 20, 1987May 17, 1988Aaton RgDevice for guiding a film in a cine camera
U.S. Classification352/227
International ClassificationG03B1/42, G03B21/43, G03B1/56
Cooperative ClassificationG03B1/42, G03B1/56, G03B21/43
European ClassificationG03B21/43, G03B1/56, G03B1/42