US2587183A - Removable geneva movement for motion-picture projectors - Google Patents

Description

MANDERFELD REMOVABLE GENEVA MOVEMENT FOR Feb. 26, 1952 MOTION-PICTURE PROJECTORS 5 Sheets-Sheet 1 Filed Oct. 14, 1947 Feb. 26, 1952 E. c. MANDERFELD 2,587,133

REMOVABLE GENEVA MOVEMENT FOR MOTION-PICTURE PROJECTORS Filed Oct. 14, 1947 5 Sheets-Sheet 2 In T/EJ? z ar J manuEJ 8.177 andazji jd $1M vaflfiw 1952 E. c. MANDERFELD 2,587,183

REMOVABLE GENEVA MOVEMENT FOR MOTION PICTURE PROJECTORS I 5 Sheets-Sheet 4 Filed Oct. 14, 1947 Int e17 2 01- :E Zz7 7anue] 5. .777 and mam si i Feb. 26, 1952 E. c. MANDERFELD 2,587,183

REMOVABLE GENEVA MOVEMENT FOR MOTION-PICTURE PROJECTORS Filed Oct. 14, 1947 5 Sheets-Sheet 5 E l I me 24 I g; 24/ 2 2, 24o

lwwx' m wmzw \\\\\\\\\\V/////A///; 285 .E'manueZ 17225221 510! Patented Feb. 26, 1952 REMOVABLE GENEVA MOVEMENT FOR MOTION -PICTURE PROJECTOR/S Emanuel C. Manderfeld, Los Angeles, Calif., assignor to Mitchell Camera Corporation, Glendale, Calif., a corporation of Delaware Application October 14, 1947, Serial No. 779,789

14 Claims.

Normal motion picture projection procedure employs two projection machines, successive reelsof film being projected by alternate machines. If the intermittent mechanism of one machine is found to require adjustment or replacement it is desirable to replace it by a spare unit during the limited time (approximately 15 to 20 minutes) that the other machine is operating. Unless such replacement can be made without disturbing the relative timing of shutter and intermittent, it is necessary to re-time the shutter before the machine can be used, and there may be insufficient time to make this adjustment properly. Hence it is a great advantage to be able to replace the intermittent movement rapidly and with assurance that the shutter timing will not be disturbed.

This is made possible according to the present invention by a novel construction and arrangement of the driving connection and associated parts, by which the intermittent movement, which is constructed as a unitary, removable sub-assembly, is driven in timed relation to the shutter. The intermittent mechanism is driven by a driving gear mounted on the main frame of the machine in driving engagement with a driven gear (the driving gear for the intermittent) mounted on an intermittent driving shaft which is part of the unitary intermittent mechanism. The driven gear is removably keyed or splined to its shaft, and

novel means are provided by which it can be removed from the shaft and supported relative to the frame in engagement with its driving gear. This permits the intermittent mechanism and driving shaft to be removed as a unit from the machine without disturbing the condition of mesh of the two gears. When the intermittent mechanism and driving shaft are replaced, the shaft is inserted into the driven gear in the same relative rotational position as before, reestablishing the former timing relationship.

The procedure just described is greatly facilitated by the provision of means operable largely or entirely from outside the main casing of the projector by which the driven gear can readily be removed from its shaft during disassembly of the intermittent, and replaced and secured upon its shaft when the intermittent is replaced.

A further important feature of the invention is the provision of locking means by which all the gears of the film and shutter drive system are automatically locked against rotation (provided the timing compensation mechanism (see below) remains fixed) whenever the driven gear is removed from the intermittent drive shaft. Axial v removal of the driven gear from its shaft brings it automatically into locking engagement with locking means, which are preferably in fixed relation to the main frame of the machine. Since the driven gear remains in engagement with its driving gear, and hence indirectly with the entire driving gear train, the locking of the one driven gearelfectively locks the entire gear train. As the driven gear is again secured to its shaft, it is automatically freed from engagement with the locking means.

: mately its normal position while its shaft is removed with the intermittent unit, thus facilitating reinsertion of the shaft in the flywheel bore when the intermittent is replaced.

It i desirable during reassembly of the intermittent to be able to manipulate the rotational position of the intermittent drive shaft, as it reenters the bore of the gear-flywheel unit, by manually rotating the intermittent sprocket. The

properties of the Geneva movement make this possible only when the pin of the pin cam is in engagement with a slot of the star cam. Therefore during reassembly, and hence also during disassembly, the intermittent mechanism is preferably in a position with the pin fully engaged in a slot of the star cam. This places the intermittent sprocket midway between two positions of rest.-

A further object of the invention is to provide means for accurately indicating when the intermittent mechanism is in the position just described, and for releasably locking the mechanism in that position.

Ordinarily, there is a simple one to one relation between the rotational position of the intermittent drive shaft and the pin cam shaft of the intermittent mechanism. It is then preferable to arrange the means for locking the gear-flywheel unit so that its locked position corresponds to a rotational position of the driven pin cam shaft which places the pin of the pin cam in full "which my invention is applicable.

:J engagement with a slot of the star cam. This position is then also the locking position of the intermittent, described above, and can be established preparatory to disassembly by reference either to the gear locking means or to the indicating and locking means of the intermittent mechanism. And by locking both said locking means upon disassembly of the intermittent, the parts are automatically in correct position for reassembly. If the intermittent is to be operated after disassembly (for example, in the process of adjustment) it is unlocked for this purpose, and is then reset to its locking position preparatory to reassembly. If a replacement intermittent is to be installed, the locking means are used to set the replacement unit to the proper position for assembly. In either instance the originally correct shutter timing is preserved, and no re-timing is needed.

A clear understanding'of the invention, and of furthercharacteristics andadvantages of it, will be obtained from the following illustrative exampl'e'of its'embodiment in a typical motion picture projection'machine. This description, which is not intended to limit'the scope of the invention, isitobe read in conjunction with the accompanying drawings, of which:

Fig. 1 is aside elevation, partly cut away, showing a projection machine in accordance with the invention, with the door to the film compartment open, the aspect of this view being indicated by line"l l onFig. 3;

Fig. 2 is a vertical longitudinal section through the gear compartment of the machine, taken as indicatedby line 2 -2 in Fig. 3;

Fig. 3'is a vertical transverse section taken generally as indicated by lines 3-3 of Fig. 1 and Fig. 2;

Fig.4 is an 'enlargedvertical section along the axis'of the intermittent movement, taken as in- L dicated b'y'lirieL-J in Fig. 2;

Fig. 5 isa transverse section through the intermittentmovement, takenas indicated by line 5%5 of-Figie Fig. fi'isa section similar to Fig. 5, but taken on line li -"'6' of Fig. 4;

Fig. 7 is a fragmentary section corresponding to the left hand portion'of Fig. 4, but showing a modified form;

Fig. Sisa section likeFig. 7,but showing the gear fiywheel unit removed from its shaft;

Fig.9 is a fragmentary transverse elevation of the intermittent sprocket and its mounting taken in the aspect'oi Fig. 3 and showing partially broken away a special jig in accordance with the invention, the movement retaining ring having been removed;

Fig. 10 is a fragmentary end elevation corresp-onding to Fig. 9;

Fig. 11 is a'section taken as indicated by line ll--l| inFig.9;and

Fig. 12 is a fragmentary axial section of the intermittent sprocket shaft showing a modified form of jig.

In order to explain fully the characteristic functions of my present invention, I describe first a typical form of projector mechanism to Certain features of the particular projector mechanism here shown are the subject matter of a co-pending application filed by me and George A. Mitchell on' Oct. 14, 1947, Ser. No. 779,702, issued June 27,

as Patent 2,513,195. The projector mech- 'anismin and ofitself is not the subject matter of 'thepresent application, except insofar as certain features of it may co-operate in the present invention. Other than that, the immediately following description is to be taken as typifying any projector mechanism to which my invention is applicable.

Numeral It! in the drawings indicates a frame or casing on and in which the various parts and subassemblies of the machine are mounted, and which serves also as a housing, enclosing the working parts of the machine. Frame 59 includes side walls and a central vertical partition l5 which divides the interior of the frame into a film compartment i6 (Fig. 1) and a gear compartmen't i! (Fig. 2). Access to film compartment 16 is through a door hinged to frame H] at 2i and indicated in open position at 2%. Access to gear compartment 1'? is obtained by removing cover plate 23.

The motion picture film to be projected, indicated generally at 25, is carried on a reel in magaZine SH, from which it is drawn through an opening in frame [8, indicated'schematically at 3|, by pull-down sprocket 32. A sprocket clamp, indicated generally at 33, maintains the perforated film in engagement with the sprocket teeth in the usualway. The film passes next via a loose film loop 35 to the film chute 35 which lies between the fixed film trap 38 and the film gate 40.

Gate '49 is movably mounted on rails 4| to facilitate threading of the film, and can be moved away from trap 33 by merely moving the handle 530f gate control lever 42 to the right in Fig. 1. This motion first rotates lever 42 counter-clockwisearound its pivoted connection-44 to the gate, li'iting'lev'er pin 55 out of side leg 41 of L-shaped slot 46 and unlatching the gate, and then moves the gate'tothe right on'rails' ll. After threading, the'gate is relatched bymerely moving handle 43 to'the left inFig. 1, first sliding the gate on rails 4| into closed position and then rotating lever 42 clockwise so that pin 45 enters latch slot 41. The above described g'ate'operating device is not apart ofthe' presentinvention.

Film trap 38 carries a removable aperture plate '48'inwhich'islocatedthe film aperture 49 (see Fig. 3) of theprojection system. The film is in termittently draw'n'past aperture 49 by intermittent sprocket 50, successive picture frames of the film being momentarily brought to rest in register with the "aperture. Intermittent sprocket clamp "5| is shown'supported on the lower end of movablefilm gate 40. The film next passes via loosefilmloop'52to hold back sprocket 54, providedwith the usual sprocket clamp 55, from which it is drawn bymeans not shown through an opening '56 in casing ill to a take-up reel or to oth'erapparatus such as a conventional sound head.

The projection system includes a light source such as an arc lamp and condensing system mounted in a lamp house indicated schematically inF-ig. 1 at E8 and delivering a beam of concentrated light along the'optical axis 6! of the projector. The light beam passes into the rear shutter housing 53, where it is intermittently intercepted by rotating rear shutter 65, mounted on shutter shaft'fifi (see below). When not intercepted by the shutter, the light passes through severalsuitable openings in case Hi, in sight box 69 and (under operating conditions) in dowser and fire shutter assembly 70, and then through aperture 49 in plate 48 to illuminate the area of which is framed byfilm aperture 49. The various parts andapertures mentioned in the immediately preceding sentence are not shown or described in detail, as not related directly to the present invention. Light transmitted by the film traverses an opening schematically indicated at 49a in film gate 40 and passes through projection lens I2, which forms an image of the film on the screen (not shown). An aperture, indicated at It, in the front wall of case I transmits the light beam from the lens. A front shutter 15, mounted on shutter shaft 36 in front shutter housing It, cooperates with rear shutter 65 in the usual manner. Projection lens I2 is suspended from ways parallel to optical axis SI and is adjustable for focus under control of handle H. The details are not necessary to the present invention.

Rear and front shutters 65 and I5 are separrately adjustable on shutter shaft 66 by any suitable means, such, for example as rear and front shutter hubs 51 and which are releasably clamped to shutter shaft 66. The shutters are so set on the shaft as to give the most advantageous timing relation both between the cooperating but distinct action of the separate shutters upon the light beam, and between the combined action of the shutters collectively and that of the intermittent film moving mechanism. For clarity in the present description it will be assumed that the two shutters are properly adjusted on their common shaft with respect to each other, and that the shaft-or the shutters together on the shaftare in approximately the correct rotational phase relation to the intermittent mechanism.

In the form illustrated the intermittent mechanism is mounted as a unit within a housing 80 (see Figs. 4, 5 and 6) which includes a generally cylindrical case 8| and a cover plate 82 which is secured to one face 83 of case 3| as by screws 84 and a single locating pin 35. (See Fig. 1.)

Outer cylindrical surface 88 of case 8| is journaled in circular openin 89 in frame partition I5, and is located axially by flange 90 of cover plate 82, which fits under cooperating flange 9| of retaining ring 92. Intermittent housing 80 is thus rotatable in the frame partition I5, and is removable as a unit in an axial direction to the right in Fig. 5 after removal of retaining ring 92.

Intermittent sprocket 50 is rigidly mounted on star cam shaft 95, which carries also star cam 96 of an intermittent mechanism of the Geneva type, and which is journaled in an axial bore 91 in cover plate 82 on an axis coincident with the axis of rotation of case @I. The pin cam 98 of the Geneva mechanism is rigidly mounted on pin cam shaft 99, which is journaled in bushing I013. Shaft 99 is adjustable in position to adjust the engagement of gears I05, I06; and cover 82 is also adjustable to adjust the engagement of the Geneva pin cam with the star, but those features do not enter into the present invention.

Pin cam shaft 99 carries also gear I95 which is engaged and driven by pin cam driving gear I96, mounted rigidly on the inner end of intermittent drive shaft I 08. The latter shaft is journaled in case 8| coaxially with star cam shaft 95 (subject to very slight variation resulting from the adjustment of cover 82, mentioned above) and hence coaxially with both intermittent sprocket 5E) and journal 89 of intermittent housing 80. The axial position of shaft I08 is defined by gear I05 at the inner end and lock nuts I39 at the outer end of its journal I94. The outer end of shaft I08 projects from housing 80 (to the left in Fig. 4) and carries intermittent driving gear III) and flywheel III, which are preferably either formed integrally or securely connected together, to form a unit, as by forcefitting the flywheel over the gear hub I IOa. This unit is removably keyed or splined to shaft I08, as indicated at H2, and is axially secured to the shaft by a retaining member H5. This retainin member, in the form illustrated, is threaded to the end of shaft I08 in the manner of an ordinary retaining nut, and engages axially transverse surface II6 of gear III), releasably looking the gear and flywheel I II to the shaft. Further details of the structure and functions of member H5 and associated parts are described belowas a part of the present invention.

The rotational position of intermittent housing 80 in its journal 89 is determined by manual adjustment of framingknob I20 or I2I (see Fig. 3). These are rigidly mounted on opposite ends of framing shaft I22, which is journaled as shown in Fig. 3 at I23 and I24 in the outer wall and in partition I5 of case Ii). Framing shaft I22 is linked by framing gear I25 and idler I26 to gear sector [27, cut in a portion of the periphery of case 8|, as shown particularly in Fig. 5. Rotational adjustment of knob I29 or I2I is transmitted by gears I25, I26 and sector I21 to the entire intermittent unit 80. This has the effect of adjustably rotating intermittent sprocket 59. This changes the longitudinal position in which the film is momentarily stopped in front of film aperture 49, and is used to correct the framing of the film when necessary.

Rotational adjustment of intermittent housing BI], in addition to the framing action just described, carries pin cam shaft 99 and pin cam driven gear I05 bodily around shaft I68, which carries pin cam driving gear I85. This causes gear I95 to roll on gear Hi5, rotating pin cam 98 with reference to housing 80, and hence also with reference to star cam 96 of the intermittent mechanism. This alters the phase relation of the intermittent mechanism with respect to intermittent driving gear IIEI. For example, if housing 38 is rotated clockwise in Figs. 1 and 6 to move the film downward at aperture 49, pin cam 98 turns clockwise through a corresponding angle with respect to casing 8|. This is opposite to its normal operating rotation, and therefore retards the beginning of the next engagement with star cam 96. In other Words the phase of the intermittent action has been delayed with respect, for example to the rotation of intermittent driving gear Ho. The shutter action, normally linked in a definite timed relation to gear I I0, must be similarly delayed with respect to that gear, if the proper phase relation between the intermittent and the shutter is to be maintained. Such compensation of the shutter timing is obtained through the shutter drive gear train, under direct control of the rotational framing motion of intermittent housing 89.

A spur gear sector I39 on case 8| engages circular rack teeth I3I on cylindric rack bar I 32. The rack teeth I 3| on bar I32 are of spur form but extend circularly around the cylindric bar so that the bar may be rotated without affecting its longitudinal position with relation to gear sector I30. Rotational motion of housing produces a corresponding longitudinal motion of rack bar I32, which is slidably and rotatably journaled at I33 and I34. Yoke I35 is longitudinally adjustably fixed on rack bar I32 by axial threads I31, and embraces helical gear I4I which ismountecl on jackshaft M2,,parallel to shutter shaftffibgby meansof splines I455, so that the gear isrotationallyfixed but longitudinally movable on theshaft. Helical gear MI is inmesh with helical gear Iii), which is rigidly mounted on shutter shaft 63, the pair of helical gears forming a part of the gear train which drives shutter shaft 66 in timed phase relation to the intermittent mechanism.

The sliding motion of rack bar I32, caused by framing adjustment of the intermittent, is transmitted asaxial motion to helical gear I4I, producing relative axial motion between the two gears. That relative axial motion of the helical gears results in a corresponding relative rotational motion, and therefore rotates shutter shaft 86 with respect to those parts to which it is linked by the helical gears. Since the latter parts includeintermittent driving gear III], the result is seen to be a shutter phase shift of the required type. A shift in the proper direction and of the proper size to give accurate compensation can be obtained by correct choice of such factors as the hand and angle of the threads of the helical gears, the diameter of the fixed helical gear, and the radius of sector I30.

Fine adjustment of shutter position (phase) with relation to the phase position of the intermittent-movement, during operation, is provided for by rotating the rack bar I32 to screw-threadedly adjust the-longitudinal position of yoke I and gear MI with relation to the bar. That rotation does not disturb the longitudinal position of the bar with relation to gear sector I30 nor with relation to thephase position of the intermittent movement. It therefore changes the phase relation of the shutterby sliding gear MI longitudinally and rotating gear Mi a corresponding amount. The bar may be rotatively adjusted by any means which does not interfere with its longitudinal framing movement, and which is not affected in its operation by the longitudinal framing movement. For instance, the end of bar I32, or a cylindric member mounted on it, is provided with straight axial teeth-in effect, long spur gear teeth-as shown at I32a. A rotatable rod l32b, lying at substantially right angles to rod I32, has a screw thread of small pitch, I320, meshing in the spur gear teeth. The rod'projects through partition I5, and at its end which available in film compartment I6 (see Fig. 1) it has a formation I32d to receive a screw driver or other suitable tool to rotate it.

The principal driving connections of the projector have the main function of driving four cooperating parts inaccurate, and, in certain respects, adjustable timed relationship with each other. Those parts are the two continuously driven film feeding sprockets 32 and 54, shutter shaft 86 and pin cam shaft 99 of the-Geneva movement which drives intermittent sprocket 50. Preferred driving means are described below.

Pulldown sprocket 32 is rigidly mounted on sprocket shaft i6il,-which is journaled in boss I6I on partition I5 of the machine frame. Sprocket shaft I68 protrudes into gear compartment I1 and carries sprocket driving gear I62 rigidly mounted on the protruding shaft end.

'Holdback sprocket 54 is similarly mounted on sprocket shaft ill], which is journaled in partition I5 and also in the outer wall of gear compartment I1, and projects through that wall to the exterior of frame case I0, as indicated in Fig. 2, to serve as the initial driving shaft of the mechanism. Sprocket driving gear I12 is rigidly mounted on shaft I10 in, gear compartment IT. The twosprocket gears I62 and H2. are preferably in a common plane which alsopasses through driven gear H0 on intermittent drive shaft I08. The three gears :I62, I12 and III), are connected together by'the single intermediate gear I15,which is in direct mesh with all of them. Intermediate gearITB is shown as an idler gear lying in "the common plane of gears I22, 32 and H0, and rigidly mounted on; shaft I16 which is journaled at IT! on partition I5 of the frame.

The shutter gear train, as shown, includes in addition to helical gears I40 and MI, already described, a large bevel gear I formed integrally with intermediate gear I15, and drivingly engaging a smaller bevel gear I8I rigidly mounted onjack shaft I42. Shutter shaft 68 extends forward through front shutterhousing IE-and carries hand wheel I41 by which the entire-gear mechanism can be manually turned over.

The overall gear ratios, assuming all three sprockets 32, 5i] and 54 to have the same number of teeth (I6, forstandard 35 mm. film) are such that sprocket driving gears I52 and I'i2rotate at the same speed, and that both shuttershaft 53 and intermittent pin cam shaft 99 rotate at four times that speed. Intermittent sprocketBD makes one complete revolution for every four revolutions of the'pin cam, so that it then .has the same average speed as that of continuously moving sprockets 32 and '54. As stated, thezshutter shaft makes one revolution foreach film moving operation of the intermittent mechanism. If shutters of other types of continuously moving F sprockets of other sizes should be used, the gear ratios will be changed accordingly. For purposes of the present description itis assumed (unless otherwise stated) that the gear ratio between pin cam shaft 99 and intermittent driving shaft Ida-is 1:1, gears I and I-(lBhaving equal numbers of teeth.

The above described gear train mechanismmxcent as it relates to removal of theGeneva mechanism, is not claimed herein, but is the-subject matter of the above identified copending application, and the patentissued thereon. The description of a typical and illustrative form of my present invention, applied to projectormechanisms as typified by the foregoing, now follows.

One of'the problems involved in'makingpossible replacement of the intermittent without disturbing the shutter timing involves obtaining the correct mesh between gear sector 130 of the replaced or substituted movement, andrack teeth I3I of-rack bar I32. Since, as has been pointed out, sliding motion of the rack bar alters the phase relation of the shutter, it is essential that correctcorrespondence between the bar position and the rotational position ofintermittenthousing 80 be preserved. This is preferablyaccomplished by rotatinghousing 8D to one extreme or other of its framing motion preparatory to its removal. The extreme position .of housing 80 are preferably determined by suitable stopswhich limit the sliding motion of rack bar I32. Such a stop may, for example, be provided by contact of the left end of rack bar I32 in Fig. 2 with the wall of case I0. The extreme rotational position of housingilil corresponding to a selected. one of the extreme longitudinal positions of rack bar I32, say to the left in Fig. 2, is preferably indicated by index marks suitably placed, for example, respectively on the'periphery of cover plate 82 and on the adjacent face of partition I5, as indicated at I and ISII in Fig. 10. (Mark I9! can be directly under retaining ring "92 as in the illustrated a!- rangement, since that ring will not be in place when the intermittent is about to be removed or replaced).

The selected extreme rotational position of intermittent housing 80 in its journal 85 is then reproducible by reference to indices I90, I9 I The corresponding position of rack bar I32 is independently reproducible by virtue of the limit stop. Even with the intermittent removed and the film feeding gear train locked (see below) the rack bar can be moved longitudinally, as for making the adjustment described in the preceding sentence, by manually turning shutter shaft 66. Since jack shaft I42 is then locked, helical gear I II cannot rotate, being splined to the jack shaft. Therefore rotation of helical gear I 40 with the shutter shaft produces relative axial motion of the gears, which means axial motion of jack shaft gear I4I. This acts through yoke I35 to slide rack bar I32, and hence provides a means of adjusting the longitudinal position of that bar, and of setting it, if necessary, against its limit stop before replacing the intermittent.

If the framing adjustment is set to the selected extreme position before disassembly of the movement, and if, upon reassambly, rackbar I32 is against the stop and intermittent housing 80 is inserted into journal 89 with the index marks I90 and IBI in register, the resulting mesh of sector gear I30 with rack teeth I3I will necessarily agree with that obtaining before disassembly. As an additional precaution, checking means, such as marked teeth on the meshing parts, can be used, such markings being visible, for example, by removal of cover plate 23 of the gear compartment.

The detailed condition of mesh of gear sector I 27 and gear I25 of the framing adjustment control is arbitrary, and reouires no special attention during either disassembly or reassembly of the intermittent.

As can be seen from Fig. 4. if the intermittent housing 80 is removed bodily to the right through the journal aperture 89 in partition I5, any wheel of large diameter mounted on the outer end of intermittent driving shaft I08 will interfere with various associated elements in the gear compartment, particularly with gear I15. rack bar I32 and gear I20. It would be difficult or impossible to mount a flywheel of adeouate size on the driving s aft I58 in such a position as to avoid this interference. gear H on shaft I08 were removed as a part of the intermitt nt un t, thus taking it out of mesh with intermediate gear H5 which drives it in timed rela ion to the s u ter, it would be d fiicult or impossible to re ain the correct condition of when the intermittent unit was replaced, in view of the restricted space and lack of visibility of the gear teeth.

Such difiiculties in removing a portion of a machine without disturbing the remainder of the mechanism are well illustrated in the partic ular problem here described, but they may occur also in machines of various types and under a wide variety of conditions. The scope of the present invention is not limited to any one type of machine, but includes other situations involving the same general principles and problems.

In the presentillustrative example of the invention, the difiiculties outlined above are over-- come by releasing the gear H0 or the flywheel III, or preferably both, from the intermittent driving shaft I08, and supporting them substantially in their normal position within the machine case It; while the intermittent movement proper'with its shaft I08 is removed. When, as

Further, if intermittent driving is preferred, gear H0 is thus released, its condition of mesh with intermediate gear H5 is not disturbed, gear H0 being supported in continued engagement with gear Il5. Furthermore, the rotational position of gear H0, and hence of the entire train with which it is connected, is located by special locking means, greatly facilitating reassembly of the intermittent. These and other features of the invention will be clear from the following description of typical means embodying them.

Element H5, which will be referred to as a transfer element for reasons which will appear, is axially movable with respect to shaft I08, being shown axially threaded to the shaft at II! and having a tool-receiving formation in the form of screw driver slot 200 which is accessible from outside frame I 0 through aperture 202 after removal of aperture cover screw 203. Transfer element II5 has an inwardly facing end surface which contacts surface II6 on the gear-flywheel unit;

and an oppositely facing annular surface 205 adapted to contact surface 201 on the unit. When element I I5 is screwed inward on shaft I08, it acts as a retaining member, exerting inward axial force on gear-flywheel unit 2 I0, holding the unit against a shaft shoulder such as I0! and establishing and/or maintaining full operating engagement of the gear-flywheel unit with shaft I08 and splines IIZ. When transfer element H5 is screwed outward on threads I", its surface 205 engages surface 201 of the gear-flywheel unit, and then positively moves the latter outwardly on the shaft, breaking the spline engagement at I I2 and substantially freeing the gear-flywheel unit from the shaft.

The connection between gear-flywheel unit 2I0 and shaft I08 can be of any type which accurately defines the rotational position of the unit on the shaft, while allowing separation of the unit from the shaft by relative axial motion. If a splined joint is used, as illustrated at II 2, the splines are preferably so designed as to mate in only one rotational position, (e. g. a single spline, or two splines spaced less than apart) so that correct relative position of the parts is assured. However, even if the splines are of a type which can be assembled in several positions, (e. g. two splines spaced diametrically) the angular separation between those positions is still ordinarily relatively great, correspondingly simplifying the task of correct reassembly as compared with obtaining correct mesh of a pair of gears whose teeth have a relatively close angular spacing.

Motion of gear-flywheel unit 2I0 outward on its shaft brings it closer to outer side wall 2I2 of frame I0, and into engagement with means associated with the frame and adapted to lock the rotational position of the gear. As illustrated, those means comprise locking pin 2I5, which projects inward from wall 2I2 parallel to shaft I08 but eccentric thereto; and -a hole 2I6 in the outer face of flywheel I I I. As gear-flywheel unit 2I0 is moved outward on shaft I08 by rotation of element H5, the rotational position of the shaft having been suitably set, pin 2 I 5 enters hole 2H5, locking the gear-flywheel unit definitely in its set rotational position. This locking action preferably becomes effective before splines H2 become fully disengaged.

For reasons already outlined, that looking position is preferably one in which the pin 220 of pin cam 98 of the intermittent mechanism is fully engaged with a slot 22I of the star cam, as shown in Figs. t and 6. When, as is ordinarily the case, gears I05 and I05 in the intermittent movement have a gear ratio of 1:1; pin 226 is thus fully engaged with the star cam for a single definite position of intermittent driving shaft I08. Locking pin 2l5 and a single cooperating hole 2H5 are preferably so placed with relation to each other about the axis of driving shaft I08 that they are adapted to engage when the shaft is in that definite position, and when the rotational (framing) position of intermittent housing 80 is in its selected (extreme) position (see above).

Further progressive disengagement of threads Ill moves the outer end shoulder of transfer element I I5 into engagement with the inner face of frame Wall 2l2, so that, upon continued rotation of element l l5, shaft I08 is positively forced in an axial direction away from that wall. That motion is communicated through thrust bearing m9 of shaft N18 to the whole intermittent housing 80, and (retaining ring 92 on partition l5 of the frame having been removed) the housing 80 is bodily moved a short distance axially with respeet to, its journal 89 in. partition l5, facilitating ts com le e m nu o aly h Zlll remains in substantially its normal posit but in engagement with locking pin 2l5.

Supporting means are provided to support the gear-.liywheel unit with respect to the frame when. shaft I08 is thus removed. One preferred form which supporting means may take is rep resented by the upwardly facing partially oylindrical surface 230 formed on the inner face of frame wall 2l2, coaxial with the normal position of shaft I08 and adapted to engage and support the cylindrical flywheel Ill. The normal. clearance between the flywheel and surface 235] is preferably only about 0.010 to 0.015", so that, when shaft I08 is removed, the flywheel is supported with its axis very nearly in normal position, facilitating reinsertion of shaft I08 in the axial bore of the gear-flywheel unit when the intermittent is reassembled.

A modified form of the apparatus just described is illustrated in Figs. '7 and 8. Transfer element 5a here corresponds to element H5 of Fig. l. surfaces 205a and 206a of transfer element ll-ia are adapted to engage surfaces Zola and 205m, respectively, of the gear-flywheel unit Zllla, and perform functions similar to those already described for the corresponding surfaces in Fig. 4. Transfer element ll5a has an outward axial extension 240, which is threaded axially and is adapted to engage corresponding threads 24! in aperture 202a of frame wall 2l2, although not normally engaging those threads (Fig. 7). Threads 24l are preferably also adapted to receive a cover screw similar to that shown in Fig. 4 at 203; and have preferably the same pitch as threads Illa, by which transfer element ll5a is normally secured to shaft H2311.

With this arrangement, as transfer element I I50, is progressively disengaged from its thread ed engagement Illa with shaft llliia, prepara tor to disassembly of the intermittent movement, gear-flywheel unit 2 [a is first moved outward on the shaft by engagement of surfaces 205a and 201a, breaking tapered joint 245 and substantially freeing the gear assembly from the shaft. By the same motion, locking pin 2 l becomes engaged with hole BIB in the flywheel, as described above. Outward motion of transfer element 5:; on shaft l08a also brings the threads on element extension 240 into engagement with threads 24l in frame wall 2l2, the latter engagement taking place shortly before threads llla become fully disengaged. Further rotation of transfer element l l5a then completes its disengagement from threads Illa and shaft IBM, and also progressively moves the gearfiywheel unit toward case wall H2 and finally into firm contact with stop surfaces associated with that wall. Such surfaces are indicated at 250 and 25l in Figs. '7 and 8. They lie in a common plane normal to the axis of shaft Ma, and are adapted to engage the outer face of flywheel HI and to maintain the flywheel axis parallel to its normal position. The cylindrical supporting surface 230, described in connection with Fig. 4, is preferably provided in the present modification also. It serves mainly as a safety measure, however, since the gear-flywheel unit MM is ordinaril transferred directly by transfer element ll5a from its normal position on shaft 108a (Fig. '7) to the position shown in Fig. 8, in which it is directly secured to wall 2l2 by the transfer element. Unit Zllla is similarly transferred back to normal position on shaft IOBa, after the latter has been replaced, by the simple operation of rotating transfer element N54 to progressiviily disengage threads 2 and engage threads Illa, disengaging locking means 2|5, 216, and reenga ging tapered joint,245.

The rotational position of the gear-flywheel unit on. shaft l08a is preferably defined uniquely by any suitable means, such as by pin 255, in the hub of gear llO, which enters axial slot 256 in fixed relation on the shaft.

An example of locking means for the intermittent movement, as contemplated by the invention, is a form of jig which can be releasably e ured to the intermit ent o ket. 1' t9 th sprocket shaft if the sprocket is removed, in a definite and accurately reproducible rotational position with respect to the star cam of the mechanism, and which then cooperates with elements on the intermittent housing in such a way as to releasably lock the position of the intermittent mechanism by locking the rotational position of the jig with respect to the intermittent housing.

An illustrative embodiment of such a jig and suitable cooperating elements on the housing is shown in Figs. 9, l0 and 11. The cooperating means are shown as pins 260 which are inserted radially in the periphery of boss 26l on cover plate 82, in positions which are symmetrically distributed at QO-degree intervals (for a fourpoint star cam) about the axis of intermittent sprocket 50. The jig includes a member 265 in the form of a flat bar with transverse shoulders 266 on its inner face adapted to engage the flanges 26l of intermittent sprocket 50 and confine the bar 265 to a definite position axially of the sprocket. The inner face of the bar also has a longitudinal slot 268 ofsuitable cross section to fit over the sprocket teeth. When applied to the sprocket, bar 265 is prevented from moving circumferentially by engagement of slot 268 with teeth on both flanges of the sprocket, as shown in Figs. 9 and 10. Bar 265 is pressed radially against the sprocket, and thus secured in a completely defined position, by clamping means of any suitable kind, the means shown comprising the spring clip 210 of general U- shape, one end of which is fastened, as by rivets 2', to the outer face of bar 255, and the other end of which is shaped to fit the curve of the axially central cylindrical portion 212 of the sprocket.

Bar 265 carries a finger 215 in the form of a flat spring which extends longitudinally of the bar, one end being anchored to the bar, as by the rivets 2H, and the other free end extending beyond the end of the bar over the generally cylindrical outer portion of boss ZGI on cover plate 82. The free end of finger 215 is formed, as indicated in transverse section in Fig. 11, with a central groove 2'16 adapted to enclose the end of any selected pin 250; and with raised lateral Wings 211 adapted to engage the pins as the sprocket is rotated and lift the finger onto them. The form of groove 216 and the angle and stiffness of finger 215 are such as to produce a firm detent action as the finger end passes onto each pin, effectively locking the sprocket in a sharply defined rotational position, and yet a1- lowing the finger to lift and release the sprocket if any unusually strong torque is applied to it. The sprocket can also be released at any time by manually raising the end of finger 215 out of contact with pin 26!).

For purposes of description it will be assumed that two of pins 260 are located accurately in that axial plane of star cam shaft 95 which passes through the axis of pin cam shaft 99, and which will be called the axial plane of the movement. This is the plane of the paper in Fig. 4. The diametral line through the other two pins then lies normal to said plane. If sprocket 5D is secured to its shaft 95 in such a rotational position relative to the star cam 96 that four sprocket teeth of each set are in the axial planes of the four slots 22! of star cam 96, those teeth will be directly opposite respective pins 269 when the sprocket is at the midpoint of an intermittent motion (Figs. 4 and 6). In a rest position of the sprocket, those four teeth will project at 45 degrees from the said axial planes, and will lie midway between adjacent pins 269. Thus if jig bar 265 is applied to the sprocket in its rest position (which is readily determined by the operator) and is placed over sprocket teeth which in that sprocket position lie midway between adjacent pins 260, (which can readily be judged by eye) then at the midpoint of the intermittent motion, with pin 220 in full engagement with a slot 22I, the jig will be directly opposite a pin 260 and ready to lock the intermittent mechanism in the desired relation of full engagement.

An alternative form of jig is illustrated in Fig.

12, for use when the intermittent sprocket is not present on the shaft. The jig is then removably mounted directly on the sprocket shaft 95, in a definite rotational relation to the shaft. The jig shown in Fig. 12 is a cylinder 280 of the same general overall dimensions as the sprocket, with a suitable looking finger 215a which is substantially the same as that shown in Figs. 53-11, and which operates in the manner already described. The jig is secured to the shaft by any suitable means, such, for example, as the same mounting means employed for the sprocket. As illustrated, these comprise a washer 285 with a square central hole which engages the square end section 286 of the sprocket shaft 95. An ear 281 on the washer is bent to engage a fitting hole 286 in the face of the jig or sprocket, defining its rotational position. Retaining screw 2:39 holds the Washer in position and holds the jig or sprocket firmly against shoulder 290 on the shaft 95.

The position on the sprocket shaft of the type of jig just described is determined by its construction (specifically, in the present illustrative example, by the position of hole 283 which receives washer ear 281) in such a way that jig finger 215a is directly opposite a pin 260 when the intermittent pin 220 is in a fully engaged position, as already described. If pins 260 are located as before described, then jig finger 215a is located on the shaft in line with a star-cam slot. Thus in applying this type of jig. the operator does not need to give any special attention to its rotational position on shaft 95.

The same location method may be applied to the use of the jig of Figs. 9 and 10. For instance, if finger 281 be located, by hole 288, so that the finger is in the axial plane of a starcam slot, and also in the axial plane of a pair 9f sprocket teeth (as illustrated in Fig. 10) then the application of the jig to that pair of sprocket teeth and to any one of pins 269 will set the intermittent mechanism in the desired position. Or, with the same operating result, the sprocket may be set on the shaft so that four pairs of its teeth are in the planes of the star-cam slots, and those four teeth-pairs may be indicated by any suitable markings.

The preferred procedure in disassembling in intermittent movement in accordance with the present invention involves rotating the intermittent housing to the selected extreme of its framing motion (bringing index marks I90, I9I into register), removing retaining ring 92, attaching a suitable jig to sprocket 50, or directly to shaft if the sprocket has been removed, and turning over the machine until finger 255 of the jig engages one of pins 250 and locks the intermittent mechanism in a mid-position of itsmotion. (The order of the stated operations is largely arbitrary.) This brings the intermittent driving shaft to a rotation position in which hole 2 I B in flywheel I I I is axially opposite locking pin 2| 5 and ready to engage it.

Transfer element H5 is then moved outward on shaft I09, as described above, transferring the gear-flywheel unit from the shaft to its rotationally locked position supported on wall 2I2 of the machine case, gear III) remaining in mesh with gear I15. The movement housing 80 is then removed axially from its journal 89 in case partition I5 into film compartment I6 and out through film compartment door 2'3.

In replacing the intermittent, either after readjustment or by another unit, the intermittent mechanism is first locked in fully engaged position by means of a jig, as has been described. Rack bar I32 of the machine is checked and adjusted if necessary to set it in the selected extreme position of its sliding motion. The shutter is then in the same position it was in at the time of removal of the intermittent, due to the locking of the gear train at the gear H9. The intermittent movement is then inserted into its journal 59 with index marks I96, IS in register. This brings gear sector I21 into (arbitrary) mesh with gear I25, and brings gear sector I 39 correctly into its previous mesh with teeth I3I of rack bar I32. It also introduces the outer end of intermittent driving shaft I08 into the axial bore of gear-flywheel assembly 2H) in the correct relative rotational position for proper engagement of the locating splines or similar means. Those means, in fact, preferably become partially engaged as a result of thus inserting the intermittent.

Transfer element H5 is then operated as described to transfer gear-flywheel unit 2I0 from the supporting and locking means on the case back to shaft I98, still preserving its mesh with gear I75, and to secure it upon that shaft. Finally, retaining ring 92 is fastened to case paras its main functions, first, to restore the initial phase relationship of the shutter timing compensation mechanism specifically by reestablishing correct mesh of gear sector I with rack bar 32; and second, to restore the initial phase relationship of the gear train connecting the intermittent mechanism and the shutter, specifi cally by correctly mating splines H2. The steps of the procedure primarily concerned with the first function are the initial setting of the framing adjustment to a definite position (chosen as a limit position for convenience) before disassembly of the movement; and, before or durits reassembly, the resetting of the intermittent housing and of the rack bar independ ently to the same position to which they Were initially set. The described limit stop for the rack bar and the indexing of the movement housing are examples of means which facilitate the independent resetting of those parts.

The second described function is made practicable by maintaining gear m and H5 in mesh, thus replacing the relatively difficult operation of reestablishing a correct condition of mesh of two gears by the relatively simple operation of restoring correct engagement of a splined or keyed joint. Further, the mating of the latter joint is facilitated, and (if a multi-position type of spline is used) its correct mating is assured, by those features of the invention which relate to releasably locking the two members to be joined (in the present instance gear H9 and shaft Hi8) in definite rotational positions before they are separated, and then either maintaining or reestablishing those locked positions preparatory to reassembly. Since gear most readily locked with relation to the main frame of the machine, while shaft me is preferably locked with relation to the intermittent housing, which is rotatable with respect to the main frame, the effectiveness of the locking procedure in bringing shaft and gear back together in correct relative position depends upon control. of the rotational position of the intermittent housing with reference to the main frame. Such control, obtained in the present illustrative example by means of index I90, Isl, also plays an important role in connection with the first main function described above.

The preferred procedure for locking shaft I08 involves locking the sprocket or star cam shaft of the intermittent mechanism in a position in which the pin of the intermittent is engaged, and preferably fully engaged, with a slot of the star cam. Only in such a position of the intermittent is rotation of intermittent drive shaft 5&3 subject to control from the sprocket shaft. This general method of locking drive shaft m8 via sprocket shaft has the advantage that the locking means are under direct control from film compartment it of the machine. Thus, as shaft H38 and gear Ht are brought together, if splines H2. do not immediately mate, the operator can release the locking meanson the sprocket shaft (by. lifting finger 215 ofi pin 260) and can then rock the-relatively, inaccessible driveshaft I08 to H0 is work the splines into engagement, by manipulating the relatively accessible sprocket shaft 95.- If he does that with the intermittent case in its indexed position, all the parts will then be restored to the original phase relations. Consequently it is not absolutely necessary that the movement itself be locked if the case is directly registered on the frame, as under these circumstances registration of the gear and of the case becomes registration of the movement upon mating of the spline. By the same considerations, the case need not be directly indexed on the frame if the movement is locked; in that event simple rotation of the case to bring the mating splines into register (which can be felt) has the direct effect of registering the case in its previous position relative to the frame. In that circumstance the registered position of gear Ill] and the registered position of the intermittent mechanism become in effect a registration of the intermittent case with reference to the frame and to the rack bar I32. For the purpose of facilitating the latter procedure it is useful that the single spline i I2 begins to mate before gear sector I30 has engaged rack teeth 53% (see 4).

It is possible, but less convenient, to replace the described locking of the rotational positions of gear I50 and shaft 508 by a system of index marks or the like, which permit the parts to be reproducibly placed in proper rotational relationship to mate correctly. An advantage of the preferred system is that correct mating is assured without the uncertainty and delay of referring to marks. It is possible further, when a single-position type of spline is used, to omit both locking and reference marks, merely varying the relative rotational positions of the parts to be mated by a trial and error method until mating is obtained. Such a procedure is difficult for a number of reasons, particularly because there is no feasible control over the rotational position of shaft it'd except in that angular range in which the pin of the intermittent mechanism engages a slot of the star cam, as explained above.

All of the above discussion is based upon the assumption that gears lab and W5 which connect drive shaft Hi8 and pin cam shaft 99 within the intermittent housing have the usual gear ratio of l 1. If, instead, the ratio of gears M5, E06 is such that drive shaft H18 makes, say, two revolutions to every one revolution of pin cam shaft 99 (the remainder of the gear train being changed correspondingly), no modification is required in the preferred procedure described above. In fact, that procedure becomes particularly advantageous. With a 1:2 gear ratio of the kind just described, all positions of full engage ment of the intermittent pin with the star cam correspond (as before) to the same rotational position of drive shaft I 38, which is the preferred locking position of the shaft in accordance with the invention. However, only alternate appearances of shaft H18 in that position correspond to intermittent pin engagement, the other appearances occurring when the intermittent is in exactly opposite phase. and hence also when the shutter is in opposite phase to its position during intermittent pin engagement. If, under such conditions, the gear-flywheel unit is not locked in rotational position while disconnected from shaft H18, it may be rotated accidentally an odd number of revolutions, shifting the phase of the shutter by degrees. If the intermittent is then replaced with the intermittent mechanism itself. in the same phase position inwhich itwas removed, the shutter timing will be off by 180 degrees, even though shaft I08 enters the gearfiywheel unit in the original relative position. By locking the gear-flywheel unit in accordance with the invention as described above and looking the intermittent mechanism in its position of full engagement, this difficulty is avoided.

If gears I and H56 have a ratio of 1:2, say, in the opposite sense, so that pin cam shaft 99 makes two complete revolutions for every revolution of driving shaft I08 (corresponding changes being made in other parts of the gear train) there are two positions of shaft I08, separated by 180 degrees, in which the pin of the intermittent is in full engagement with a slot of the star cam. Those two positions are fully equivalent so far as timing of the shutter is concerned, and either one of them is a satisfactory locking position for shaft I08. As the movement is operated, successive positions of full pin engagement correspond alternately to one or other of the two looking positions of shaft I08. Under such conditions no change need be made in the apparatus described for locking the intermittent movement in a fully engaged position, but the locking means forthe gear-flywheel unit may then be preferably adapted to operate in either of the two positions in which that unit may be found after the intermittent mechanism has been locked. For example two holes 2I6 can be provided at suitable diametrically opposite positions on flywheel IIO, adapted respectively to receive pin 2 I 5 when shaft I 08 is in its two locking positions described above. Also, spline I I2 may then be preferably of the two-position type (e. g. two splines spaced d ametrically), both mating positions of the spline corresponding to the same phase relation of the intermittent mechanism. With those changes in the preferred form of the apparatus, the procedure already described for replacing the movement can be used, no effort being made to distinguish between the two locking positions of the gear-flywheel unit, or between the two mating positions of splined joint I I2.

I claim:

1. In a machine having a frame and a shaft normally journaled on a fixed axis with respect to the frame and removable therefrom by axial movement in one direction: driving means for the shaft, comprising a driving gear rotatably mounted on the frame, a driven gear normally releasably mounted on and exclusively carried by the shaft in fixed rotational relation thereto and in mesh with the driving gear, the driven gear being releasable from the journaled shaft by axial movement relative thereto in the opposite direction, and cooperating gear supporting formations mounted respectively on the driven gear and on the frame in normally spaced relation, the said formations being mutually engageable and acting when so engaged to support the released driven gear on the frame substantially on the said axis and in mesh with the driving gear, and the said formations being shiftable between their spaced and engaged conditions without disturbing the said gear engagement.

2. Driving means for a shaft, as defined in claim 1, the driven gear being capable of axial movement from its normal position in the said other direction with respect to the frame, and the said gear supporting formations including locking means engageable by virtue of the last said gear movement, and acting when engaged to lock the driven gear in a fixed rotational position with respect to the frame.

3. Driving means for a shaft as defined in claim 2 and in which the said locking means comprise a pin projecting from the frame eccentrically of the shaft and parallel thereto and a formation rotationally fixed with respect to the driven gear and adapted to receive the pin.

4. Driving means for a shaft as defined in claim 1, and including transfer means adapted to positively move the driven gear axially with respect to the journaled shaft to release it therefrom.

5. Driving means for a shaft as defined in claim 4 and in which the said transfer means includes a transfer member releasably threaded to the shaft and adapted to engage the driven gear by virtue of screw threaded movement relative to the shaft in either direction, and thereby to move the driven gear axially of the shaft in either direction.

6. Driving means for a shaft as defined in claim 5, and in which the transfer member has an axially facing surface adapted to engage a surface on the frame as the transfer member is unthreaded from the journaled shaft and thereby to exert on the shaft an axial thrust relative to the frame in the said one direction.

'7. Driving means for a shaft as defined in claim 1, and in which the said gear supporting means include screw threads respectively on the shaft and on the frame coaxial with the said axis, a transfer member adapted for threaded engagement with either of the two said screw threads and shiftable from one said engagement to the Iii) other by screw threaded movement parallel to the said axis, and cooperating formations on the transfer member and on the driven gear positively limiting their relative axial movement.

8. In a machine having a frame and a shaft normally journaled with respect to the frame and axially removable therefrom; driving means for the shaft, comprising a driven gear shiftable by axial movement between an operating position mounted on the shaft in fixed rotational relation thereto and an idle position mounted on the frame in fixed rotational relation thereto, a driving gear journaled with respect to the frame in driving mesh with the driven gear in both said positions thereof, a transfer member releasably threadable by coaxial threads to the shaft and to the frame, respectively, and axially shiftable by screw threaded movement between the shaft and the frame, and adapted by the said movement to shift the gear between its two said positions without disturbing the said gear engagement.

9. In a motion picture projection machine having a frame and a unitary intermittent movement which includes an intermittent mechanism and a shaft in driving relation to the said mechanism, the said intermittent movement being bodily removably mounted on the frame; driving means for the intermittent movement, comprising a driven gear normally rotatively fixed on the said shaft and axially removable therefrom, a driving gear rotatably mounted on the frame in direct driving mesh with the driven gear, and cooperating means mounted respectively on the driven gear and on the frame in normally spaced relation, the last said means being mutually engageable and acting by virtue of such engagement to support the driven gear on the frame in continuous mesh with the driving gear as the intermittent movement is removed.

10. Driving means for an intermittent movement as defined in claim 9 and in which the said cooperating means include locking means for releasably locking the frame supported driven gear in fixed rotational relation to the frame.

11. In a motion picture projection machine having a frame and a unitary intermittent movement which includes an intermittent mechanism and a shaft in driving relation to the said mechanism, the said intermittent movement being bodily removably mounted on the frame; driving means for the intermittent movement, comprising a unitary driven gear and flywheel normally rigidly mounted on the said shaft and axially removable therefrom, a driving gear rotatably mounted on the frame in direct driving mesh with thedriven gear, and cooperating means mounted respectively on the frame and on the driven gear and flywheel unit in normally spaced relation, the last said means being mutually engageable and acting by virtue of such engagement to support the gear'and flywheel units on the frame with the driven gear in continuous mesh with the driv ing: gear as the intermittent movement is removed.

12. In a motion. picture projection machine having a frame and a unitary intermittent movement which includes an intermittent mechanism and a shaft in driving relation to the intermittent mechanism, the said intermittent movement being mounted on the frame and being bodily removable therefrom by movement axially of the shaft; driving means for the intermittent movement comprising in combination a driven gear, cooperating means on the gear and the shaft for releasably mounting the gear in an operating position on the shaft in fixed rotational relation thereto, cooperating means on the gear and the frame'for releasably mounting the gear in an idle position on the frame, a driving, gear rotatively mounted on the frame indirect mesh with the driven gear in both of the said positions thereof,

andmeans" for shifting the driven gear between its two said positions while the intermittent movement is mounted on the frame and without disturbing the said gear engagement.

13. Driving means for an intermittent movement as defined in claim 12, and including also means for releasably locking the intermittent mechanism in a motion-transmitting phase of its cycle.

14. In a motion picture projection machine of the type that includes a main frame and an intermittent' film moving unit comprising a Geneva mechanism, a sprocket shaft driven intermittently by theGeneva mechanism, and a drive shaft coaxial with the sprocket shaft and in direct driving relation to the Geneva mechanism,

the said intermittent unit being mounted in the frame for rotationalfilm framingmovement coaxial with the drive shaft, and being removable from the frame by movement axially of that shaft; driving means for the Geneva mechanism comprising in combination a driven gear, cooperating, means on the gear and on the drive shaft for releasably mounting the gear in a normal operating position on the shaft in a definite fixed rotational relation thereto, means for registering a definiterotational position of'the intermittent unit with respect to the frame, means acting, independently of whether the intermittent movement is mounted on the frame, to releasably lock the sprocket shaft in a definite phase position within the movement phase of its intermittent cycle, the said parts being such that when the sprocket shaft is locked inthe said phase position and the intermittent unit is'in its said registered position the driven gear in operating position has a definite rotational relation to the frame, cooperating means on the gear and'on the frame for mounting the gear releasably in an idle position on the frame when the intermittent unit is removed, and for locking the gear in substantially the said definite rotational relation to the frame, and a driving gear rotatively mounted on the frame in direct mesh with the driven gear in both the operating and idlepositions thereof, the driven gear being shiftable between its operating and idle positions without disturbing the said gear engagement.

EMANUEL C. MANDERFELD.

REFERENCES CITED The following references are of record in the file of this patent? UNITED STATES PATENTS Number Name Date 770,937 Smith Sept. 27, 1904 1,065,763 Angebrandt June 24, 1913 1,292,448 Emory Jan. 28, 19.19 1,406,878 Leonard Feb. 14, 1922 1,537,874 Petrosky May 12, 1925 1,545,684 Nutt et a1 July 14, 1925 1,661,988 Ayres Mar; 6, 1928 1,788,110 Junghans Jan. 6, 1931 1,818,048 Dina Aug. 11, 1931 2,196,358 Heinisch Apr. 9, 19.40 2,205,473 Fishburn June 25, 1940 2,260,569 Holmes Oct. 28, 1941 2,306,739 Maier 1. Dec. 29, 1942 2,312,663 Miller Mar. 2, 1943 2,388,794 Miller Nov. 13, 19.45

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