US2026134A - Portable talking motion picture apparatus - Google Patents

Description

Dec. 31, 1935. R. P. MAY ET AL 2,626,134

PORTABLE TALKING MOTION PICTURE APPARATUS y Filed Feb. 12, 1952 7 Sheets-Sheec l ccc NVENTORS RUSSELL P. MAY

B'Y HAROLD ,HOLDEN 7 /wvl/z/ o EY Dec. 31, 1935. R, P MAY ET AL PORTABLE TALKING MOTION PICTURE APPARATUS Filed Feb. 12, 1932 '7 Sheets-Sheet 2 lNvl-:NoRs RUSSELL P. MAY BYHARQLD HOLDEN ,Q4-vm oRNl-:Y

Dec. 31, 1935. R. P. MAY ET AL. 2926134 PORTABLE TALKING MOTION PICTURE APPARATUS Filed Feb. l2, 1932 7 SheeS-She'l 3 INVENTORS RUSSELL P. MAY HAROL HOLDEN r ,Mw-1 ATTORNEY Dec. 31, 1935. R. P. MAY ET Al. 026,134

PORTABLE TALKING MOTION PICTURE APPARATUS Filed Feb. 12, 1952 'r sheets-sheet 4 INVENTORS RUSSELL P. MAY HAROLD C HOLDEN De@ 3L W35, R P. MAY ET AL 2,9%34

PORTABLE TALKING MOTION PICTURE APPARATUS Filed Feb. l2, 1932 '7 Sheets-Sheet 5 INVENTORS RUSSELL P. MAY HAROLD C HOLDEN @s-@o @L Hgc R p MAY ET AL ZQ PORTABLE TALKING MOTION PICTURE APPARATUS Filed Feb. l2, 1932 7 SheecS--Sheel 5 l NTORS P. MAY

HOLDEN @@"Jr, 3L @935 R P. MAY ET AL ZQQTZQQBL@ n PORTABLE TALKING MOTION PICTURE APPARATUS Filed Feb. 12, 1952 7 sheetsheei 7 lMENTON RUSSEL, MAY

BY HAROD C- HOLDEN ORNEY Patented Dec. 31, 1935 UNITED STATES PATENT OFFICE PORTABLE TALKING MOTION PICTURE APPARATUS Ware Application February 12, 1932, Serial No. 592,468

6 Claims.

The present invention relates to portable talking motion picture apparatus particularly adapted to home and educational use. It involves the provision of an improved projector, an improved sound reproducer, and an improved amplier, all built into a single, light-weight, inexpensive unit tted within a sound-proof carrying case.

One object of the invention is to provide an improved talking motion picture apparatus adapted to use 16 mm. lm which carries thereon a sound-track of one of the usual types in commercial use.

Another object of the invention is to provide such an apparatus which is capable of high quality sound reproduction from such a lm.

Another object of the invention is to provide such an apparatus which requires a minimum power -to operate it and which can therefore be operated from any ordinary household power supply.

Another object of the invention is to provide an extremely compact and rugged combination of motion picture projector, sound reproducer and amplifier.

Another object of the invention is to provide a motion picture projector mechanism which is built into a unitary structure with the driving motor.

Another object of the invention is to provide a sound reproducer which requires no individual or separate drive mechanism.

Another object of the invention is to provide a photocell and amplifier structure which is adequately shielded both mechanically and electrically by the remainder of the construction of the soundhead.

Another object of the invention is to provide a projector which is so sound-proof as to require no projection booth or the equivalent for its operation, and thereby permit its operation in any desired location such as the midst of the audience.

Another object of the invention is the provision of an improved film gate which permits the iilm to'be driven from one row of sprocket holes only without flicker at the aperture and without the film tending to run cfr" to one side or the other.

Another object` of the invention is the provision of a carrying case for the projector adapted to permit operation of the projector therein and provided with appropriate facilities for ventilation, replacement of amplifier tubes, and the admission and exit of the film and the necessary wires.

Another object of the invention is to provide Other and ancillary objects of the invention 5 will be apparent from a reading of the following specification in connection with the accompanying drawings and its scope will be pointed out in the appended claims.

Referring to the drawings:

Fig. 1 is a side View of the projector as mounted in the carrying case and with the carrying case open for threading of the projector.

Fig. 2 is a view of the opposite side of the projector with the amplier and rectifier tubes removed and with the cover removed from the photocell housing.

Fig. 3 is a longitudinal section along the axis of the optical system of the sound reproducer.

Fig. 4 is a view partly in section from the lefthand end of Fig. 1 or the righthand end of Fig. 2 showing the interior construction of the sprocket end of the projector mechanism, and of the soundhead,

Fig. 5 is a horizontal section through the mechanism at the axis of the drive motor,

Fig. 6 is a view from the lefthand end of Fig. 2,

.with the cover plate 51 removed,

Fig. '7 shows the cover plate as removed from Fig. 6 and shows the remainder of the mechanism of Fig. 6, this View being inverted in relation to Fig. 6 in order that the relation of the parts may be more apparent,

Fig. 8 shows a modied form of film gate; and

Figs. 9, 10 and 11 show details thereof,

Fig. 12 shows a means for adjusting the film laterally at the sound take-off.

The film with which this projector is intended to cooperate is of the conventional 16 mm. width and is provided with pictures of exactly the same size as are ordinarily used on 16 mm. amateur film. The main difference from the usual amateur film is that one roll of sprocket holes is omitted and a sound-track preferably of the variable area type and approximately 6/100ths of an inch in width is located approximately where the row of sprocket holes would have been. Other differences are that the film is made to run at a speed of 24 frames or pictures per second which is the usual speed in talking motion pictures instead of 16 pictures per second which has heretofore been usual in 16 mm. films. Thereason for this is that such pictures can be properly printed by projection when desired from standard theatre films or the equivalent Without requiring that a special negative be taken and a special soundtrack be made to be capable of reproduction in this apparatus.

The projector as shown in Fig. l is housed within a carrying case l5. This carrying case as indicated at Il is lined with appropriate soundabsorbing material to absorb any noise which might be produced by the projector mechanism, the mot-or, or the fluttering of the lm in order to avoid any disturbance of the audience, and is provided with suitable apertures for the lens as at I2, for the entrance and exit of wires as at i3, and for the entrance and exit of the iilm as at i4.

The case is also provided with ventilation apertures 9E! in the front, back, and lid, and with a door 9| at the back which provides access to the amplier tubes without removing Vthe machine from its case. The front of the case opens downwardly to provide easy access to the lm side of the machine for threading, etc.

Upon the `outside of the carrying case are dev tachably mounted the lm reel arms l5, the lower of which is driven by thebelt it which passes over the rollers l'l.

The means for fastening the lid of the case are located at the ends thereof, as shown, in order that in carrying the apparatus the weight thereof may be supported by these rigid ends.

The loudspeaker cable is plugged into the base of the machine as indicated at 259, and when the case is closed and in operating condition passes outthrough the aperture i3.

After the lm has been threaded with the case open, the case is closed and remains in closed position during operation, thereby retaining within the case not only the noise of the projector but also any stray light whichmay escape from the lamphouse.

The case is provided with a suitable leveling mechanism which may, for example, be a vertically slidable member retained by the set screw E8 or the screw i8 may itself directly control an appropriate member for raising or lowering the front end of the case.

The projector and attendant mechanism are mounted upon a base 2G. This base is preferably made from a bent sheet of metal and carriesupon it the amplifier and photo cell in a manner analogous to that customary in the manufacture of radio sets. It also carries the projector and soundhead mechanism.

The projector and soundheadmechanism will be rst described in detail and thereafter the related electrical mechanisms will be described.

Upon the base 25 is mounted an auxiliary base 2l Which is made in the form of a casting securely attached to the base 25, and ,carries the soundhead mechanism and the motor 22.

This motor 22 is an essential portion of the projector mechanism, for it carries within its housing at one end the entire drive mechanism and bearings for the sprockets, and at the other end the intermittent feed and framing mechanism; it likewise serves to support at its side the picture lamphouse and attendant optical system, and at the front there are built into the motor housing the film guides and lens mount. This motor includes a rotor 23 (Fig. 5) mounted within the stator structure 22 which is carried in the usual central casing, but in place of the usual endbells are substituted special housings provided with appropriate bearings, etc. for the rest of the mechanism. The end-bell at the lefthand side of Fig. 5 carries bearings for the shafts 3l and 32, and upon the inner ends of each of these shafts is mounted a gear as indicated upon the shaft 32 at 33 in Figs. 4 and 5. Both of these gears are driven by a gear 35 which is cut upon the one end ofV the rotor shaft 35. adjacent the other end of the rotor is mounted a flywheel which serves Yto steady the rotation of the motor, and it will thus be apparent that the shafts 3! and 32, with their attendant sprockets 3'! and 38, will be driven at a substantially` uniform speed.

Within the other end-bell of the motor is mounted the intermittent feed mechanism and its framing mechanism.

This intermittent feed mechanism includes a i..

gear 3S keyed upon the end of the rotor shaft which meshes with a gear il which is integral with the cam mechanism of the intermittent feed and with the shutter l i.

The intermittent feed is of the claw type and is best shown in Figs. 5, 6 and 7. The member 42 extends from the shaft 53 on Which it is vertically slidable to and fro through the slot i4 which is beneath the aperture d5. This member 42 carries at its end and extending through the slot G5 claws which are adapted to engage and move the film. At its other end, this member bears the arm 45 extending outwardly into the casing and adapted to slide longitudinally along the pin lli which is rigidly attached to the arm d3. A pin 4S cooperates With the aperture 5B in the member d2 to impart a vertical movement of the claw and this pin l is carried by the member 5l which is pivoted at 52 to the adjustable arm 53.

The arm 5l is provided with an aperture hav- 3 ing parallel top and bottom within which the cam 5d is adapted to operate in order to move this arm and with it the feed claw vertically.

Framing is accomplished by moving the eccentric pivot 55 about its axis by means of the knob 4 which is integral with this pivot member.

The in-and-out movement of the feed claw is accomplished by means of the cam 56 Which acts upon member 48 and which, in turn, through its co-operation with the members il and 56 causes i rotation of the member 132 about the shaft 43.

It willl thus be apparent that the claw member 42 is moved up and down a predetermined distance and also moves in-and-out of the sprocket holes at the proper times and that adjustment of 5 the position thereof at the times when the various phases of the movement will occur is readily effected by means of the eccentric 55.

It will be apparent from Figs. 5 and '7 that some portions of`the mechanism just described are 5i mounted upon the cover plate 5'! while other portions are mounted upon the end-bell of the motor 58, but that these parts are so related that the unit may be easily assembled.

One form of film gate is shown in Fig. 1. In this form of gate there is a plate 59 attached to the motor housing in front of the optical system and shutter, and this plate has an appropriately surfaced channel in it to receive the lm. Against this plate bears the pressure shoe 60 which is in the form of a pressed metal plate having appropriately formed contact surfaces for the lm and having outwardly extending ears at the top and bottom,V as shown, by which it may be 7 grasped to open it. This gate is held in closed position by the springs-5l against the pressure of which it may be opened by grasping the ears above referred to and the elongated apertures in Immediately 5 the sides of the gate Which engage the pins 62 75 may then be slid down over the pins 62, retaining the gate in open position.

A modified form of gate is shown in Fig. 8 and this particular form of gate is found to be peculiarly eiective when the film is drawn by traction of the intermittent feed on sprocket holes on one edge of the iilm only.

In this gate a backing plate 59 is provided as in the gate previously referred to, but the film is pressed toward this by a linear shoe 70. This shoe is provided with ears H which serve the same function as the ears above referred to and these ears are each provided with a notch 'l2 in their lower edges whereby the pressure shoe may be maintained in open position by drawing it outwardly and hooking these notches over the plates 13, which also serve as spring-retaining members.

The opposite edge of the nlm is prevented from fluttering by a guide 14 which extends the entire length of the gate but which, instead of being pressed rmly against the film by springs, is set at such spacing from the guide on the backing plate that the film can move freely therebetween. This avoids producing any tension on the edge of the lm which is not drawn by the intermittent and at the same time, due to the small clearance (which may be of the order of two one-thousandths of an inch) and acting in cooperation with the pressure shoe at the other edge of the aperture, prevents any flutter of the film at the projection aperture. A

'Ihe guide 'M is spring-pressed toward the shoe 59 but is stopped by eccentric headed screws l5 mounted at the top and bottom of the gate. This permits the shoe M to rise when a splice or other thickened portion of the iiim passes through the gate and at the same time provides a clearance between the shoe and the film under normal operating conditions.

In order to permit the lm to be readily threaded through the apparatus, a bar I6 is rigidly attached to the shoe 'HJ and operates in a slot in the shoe 14. When the shoe l!) is retracted by means of the ears 1l, the bars 'l5 which are provided at both the top and bottom of the gate likewise retract the shoe I4 since the movement of the shoe 'I0 is greater than the length of the slots in the shoe 14, but when the shoe 'HJ is released and permitted to ride against the surface of the lm, the pins 'l5 move forwardly in the slots when the shoe 14 contacts with the eccentric headed screw 'l5 and neither of the shoes therefore interferes with the normal operation of the other.

The film is illuminated at the aperture by means of a light of the usual incandescent type diagrammatically indicated at 80, behind which is adjustably mounted a reflector 8l which is spaced from the lamp housing 82 by the screws 83, and is retracted against these screws 83 by the screw Bbl, there being three of the screws 83 as will be seen from Figs. 4 and 5 considered together.

In front of the lamp-housing 82 is mounted the condenser lens barrel S5 which contains the usual condenser lenses 8B and is maintained in proper adjustment by the set screw 87, all as shown in Fig. 5.

The top of the lamp-house is provided with a Ventilating-hue 92 which serves to direct heated air from the lamp-house upwardly through openings 96 in the lid of the case. These openings are so positioned as to be immediately over the top of the flue 92 when the case is closed.

The cooling air is admitted through the other Ventilating openings 90 in the front and back of the case. It will be apparent that on account of the larger number of openings most of the air enters around the amplifier tubes in the rear of the case and serves to iirst cool the amplifier tubes, which must operate at a relatively low temperature, and then passes to the bottom of the lamp-house and, passing upwardly therethrough serves to cool the projection lamp which operates at a higher temperature. A minimum quantity of air is acco-rdingly required to adequately perform both cooling functions, and the structure is thus simplified. Further, the best of the projection lamp itself provides suicient draft to sumciently cool both the lamp and the amplifier tubes.

The nlm passes over the top of sprocket 31 which draws the iilrn from the upper or let-off reel and then passes in the form of a fiat loop to the top of the gate through which it is drawn by the intermittent feed mechanism already described and from which it passes in the form of another loop to the sound reproducing mechanism, which will be next described, and from thence it passes up to the sprocket 38, and then through another loop to the bottom of the sprocket 3i' which serves as a hold-back sprocket for the lower reel.

The sound reproducing system, Fig. 3, is of the usual photoelectric type including a photoelectric cell, an exciter lamp, an optical system, and means for drawing the iilm through between the optical system and the photoelectric cell.

The exciter lamp of the present sound reproducer is indicated at SSS and is mounted within an adjustable socket within the casing li. The light from this lamp passes through the optical system indicated generally at W2 and is focussed thereby in the form of a narrow line upon the sound-track of the film which is carried on the surface of the drum it, with the sound-track overhanging the inner edge of the drum. After passing through the film, the light strikes the reflecting surface 29d whence it is reected through the aperture H35 to the photoelectric cell 203 located within the member 2 i.

The ilin is held against the drum |233 by an idler it which maintains the lm iirmly in engagementwith the druin at this point.

After passing around the drum for a sufficient distance to give good frictional contact, the lm f passes over the roller i??? and then around the roiler MB, which latter roller is mounted on a shaft carrying at its other end the flywheel H19, and from this roller its the film then passes up over the sprocket 58 as before described.

The roller m3 is preferably sandblasted on its outer surface in order to provide adequate frictional contact within the small area. The action of the flywheel serves to prevent any irregularities being introduced into the motion of the film, whence the entire sound reproducing unit will operate in a uniform manner without any fiuttering or variation in nlm speed.

The drum lii is rotatable upon a shaft It@ as shown in Fig. 3. The interior of this drum is hollowed out, and a flat friction surface I H is provided. Against this friction surface suitable pressure shoe H2, of which there may be three oi' more, and which are preferably made of some such composition as oiled felt or leather, are

pressed by the springs i 53. It will be seen that the friction means H2 cooperating with the surface Hi produce a uniform braking action upon the drum and therefore cause the hlm to be rmly wrapped around both the drum and the succeeding two rollers. The braking action of the drum, by providing a constant impedance at this point, further prevents any tendency for the drum to oscillate back and forth about its axis, as Vwould be the case to a certain extent if there were no braking or damping action.

The end of the member I 23', which projects as illustrated, cooperates with a slot or keyway in the bracket 24 which is made integral with the member-2|. If the keyway is properly positioned with relation to the longitudinal axis of the film, the line image above referred to will beY accurately positioned transversely of the sound-track. y

From the sound-track the light again diverges and it then strikes the reflecting surface I 04' and, as before described, passes through the aperture |05 to the photocell which is mounted interiorly of the base 2l.

The flange |28 of the pressu:erolll IUS is fixed, Whereas the flange 29 is pressed against the film by a spring, thereby holding the sound-track edge of the film firmly against the flange |28 and accurately xing the location of the soundtrack in relation to the reprcducer.

As shown in Fig. 12, the entire side guiding member can be made adjustable by providing a ,spring tending to force the pressure roller and its supporting arm away from the base 2| toward which it is held by means of the capscrew |28 (Fig. l) which thereby serves to adjust the position of the xed flange 28. The spring serving to Vforce the arm away from the base 2l may be either a separate spring inserted between these members or the spring provided to rotate the supporting arm and thereby force the roll 106 against the drum H33 and may also serve to force the supporting arm downwardly as shown in Fig. l2. Instead of providing the capscrew, it may be desirable to use a stud-bolt i28a or the equivalent on the member 2| and provide a nut and lock-nut on the outer end thereof as this would prevent any variation in the adjustment due to vibration of the machine or the like.

The photocell 2M and amplifying tube 224, be- ,ing rather sensitive to jars and vibration, are mounted on an appropriately cushioned socket, and in the present case it is preferable to do this by a spring mounting underneath the base of the apparatus, the spring mounting carrying the rods 26! supporting the photocell socket and also the socket for the amplifying tube 2M which is the first amplifier tube following the photocell and is preferably of the screen-grid type. This integral mounting of the photocell and amplifier tube prevents relative oscillation of the grid lead to the said tube and associated parts which might produce undesirable modulations or noises. In addition this type of construction allows the use of shortest possible high impedance circuit connections.

Within the same portion of the casing are also mounted the condensers 202 and the flywheel l D9, and this portion is closed by a cover as shown at 203 in Fig. 9 which slides over the screws 204 and is retained in position by the screws 25, thus providing a light-tight housing for the photocell and at the same time electrically and magnetically shielding both the photocell and highgain amplifying tube.

TheY power transformer is located at 253B and feeds a rectifier tube indicated at 280 for supplying plate current for the amplifier tubes, which is filtered through the condenser 282 and an appropriate choke which. in the present instance, is

also used as the eld magnet of the dynamic speaker. The remainder of the amplifier tubes are mounted along the back edge of the base, the sockets being attached to the lower section of the base and most of the wiring-being conu tained thereunder.

'Ihe socket 208 at the front of the base in Fig. 1 is adapted to receive the loudspeaker plug 209,

The exciter lamp is operated either by alternating current supply through the power transl0 former or, preferably, by a high frequency oscillating current supplied by an oscillator tube which is fed from the same power supply as the amplifier.

The volume is controlled byV controlling the voltage applied to the photocell by means of a potentiometer. 'Ihe operating knob 302 of this potentiometer is arranged as shown so as to be accessible through the slot 302 when the case is closed, to permit control of the Volume without opening the case.

The apparatus described is not only compact and portable, but produces a quality of picture and sound reproduction comparable with that of the large and expensive equipment using standard film.

We claim:

1. Sound reproducing apparatus adapted to -operate with sound records on film comprising a housing adapted to enclose a photoelectric cell, a shaft mounted on said housing, a drum mounted upon said shaft, a drum adapted to carry the film sound record past a reproduction point with the sound record portion overhanging the edge thereof mounted upon said housing, means for directing light through the said sound record portion, and means for directing the light passing through the said sound record portion into the said casing and upon the said photoelectric cell.

2. Sound reproducing apparatus adapted to operate with sound records on lm comprising a housing adapted to enclose a photoelectric cell and a related amplifier tube, a drum mounted upon said housing adapted to carry the lm sound record past a reproduction point with the sound 5 record portion overhanging the edge thereof mounted upon said housing, means for directing light through the said sound record portion, and means for directing the light passing through the said sound record portion into the said casing and upon the said photoelectric cell.

3. Sound reproducing apparatus adapted to operate with sound records on film comprising a housing adapted to enclose a photoelectric cell and an amplier tube adapted to co-operate therewith supported in relatively rigid relation to each other upon a relative non-rigid base member, a drum mounted upon said housing adapted to carry the lm sound record past a reproduction point With the sound record portion overhanging the edge thereof mounted upon said housing, means for directing light through the said sound record portion, and means forI directing the light passing through the said sound record portion into the said casing and upon the said photoelectric cell.

4. Sound reproducing means comprising a drum adapted to support a sound record film with the sound record portion overhanging the edge thereof, and adjustable means for determining the amount of the said overhang, said means including a flanged roller adapted to co-operate with the edges of the film and having one flange adjustable relatively to the said drum and the 751 other flange spring-pressed toward the said rst ange.

5. Sound reproducing means comprising a drum adapted to support a sound record film with the sound record portion overhanging the edge thereof, and adjustable means for determining the amount of the said overhang, said means including a flanged roller adapted to co-operate with the edges of the lm and having one flange adjustable relatively to the said drum and the other flange spring-pressed toward the said rst iiange, the entire said roller being adjustable laterally of the said drum.

6. Sound reproducing apparatus comprising a drum for supporting the lm at the reproduction point, and a plurality of relatively stationary friction-resistance elements acting upon said drum for steadying the motion thereof, the soundtrack of said lm overhanging the edge of said drum.

RUSSELL P. MAY. HAROLD C. HOLDEN.

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