US3188876A

US3188876A - Drive mechanism

Info

Publication number: US3188876A
Application number: US206330A
Authority: US
Inventors: John D Mitchell; Jr Raymond F Finzer
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1962-06-29
Filing date: 1962-06-29
Publication date: 1965-06-15
Anticipated expiration: 1982-06-15
Also published as: DE1425771B2; DE1425771A1; GB1043538A

Description

June 15, 1965 J. rrc L ETAL 3,188,876

DRIVE MECHANISM Filed June 29. 1962 JOHN 0 MITCHELL RAYMOND E FM/ZE/LJR INVENTORS ATTORNEYS first position.

3,188,876 DRIVE MECHANISM John D. Mitchell and Raymond F. Finzer, Jra, Rochester,

N.Y., assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey Filed June 29, 1962, Ser. No. 206,330 4 Claims. (Cl. 74-203) The present invention relates to a drive mechanism for cinematographic apparatus and more particularly to an improved drive mechanism which selectively couples a unidirectional power input to a power output for driving the film actuating mechanism thereof in the forward or reverse directions.

For motion-picture apparatus, particularly for motionpicture projectors, it is desirable to be able to selectively move the film either forwardly or rearwardly at normal speed during projection, or to hold it stationary for the projection of stills. It is also desirable to drive the film advancing mechanism from a unidirectional rotating power source coupled thereto. 7

The principal object of this invention is to provide motion-picture apparatus with a novel reversing drive mechanism which is coupled to a unidirectional power source.

Another object of this invention is to provide motionpicture apparatus with a selectively controllable reversing drive mechanism for feeding the film therethrough.

Other objects and a fuller understanding of the invention can be had by referring to the following description and claims taken in conjunction with the drawings in which FIG. 1 is a side elevation view of the drive mechanism of the present invention shown in the neutral or still projection position;

FIG. 2 is a sectional view of the drive mechanism illustrated in FIG. 1 taken along the line 22;

FIG. 3 is a side elevation view of the drive mechanism of the present invention shown in the forward drive position;

FIG. 4 is a sectional view, taken along the line 4-4 of FIG. 3; and,

FIG. 5 is a view similar to FIG. 4 but showing the parts in the reverse drive position.

To better understand the novel drive mechanism described hereinbelow, a brief summary will be helpful. A drive member is rotated by a unidirectional motor. A rotatable driven member is mounted on a pivoted arm member for pivotal movement therewith to frictionally engage the drive member in a first position for rotation in one direction. A pulley belt drive interconnects the drive member and the driven member so that when the arm member and the driven member mounted thereon are pivoted away from the drive member to a second position, the belt drive is engaged and the driven member is rotated in a direction opposite to that when it is in the The arm member is resiliently mounted and adapted for selective movement between two positions to urge the driven member into either of said first and second positions.

With reference to the drawings, a preferred embodiment of our improved drive mechanism is disclosed in a combined rubber-covered friction roller 20 and pulley wheel 22 is secured to drive shaft 16 for rotation therewith in a counter-clockwise direction. The diameter of friction roller 20 is somewhat larger than the diameter of pulley wheel 22.

United States Patent 0 An arm member 24 is pivoted at one end about a stud shaft 26 suitably carried by housing 10, so that the opposite end of arm member 24 is movable laterally relative to drive shaft 16 in a plane substantially perpendicular to the axis of rotation thereof. A stud shaft 28 projects outwardly from arm member 24 adjacent its free end and along an axis substantially parallel to the axis of drive shaft 16. A driven member 30 comprising a combined friction roller 32, pulley wheel 34, and output pulley wheel 36 is rotatably mounted on stud shaft 28. Friction roller 32 and pulley wheel 34 are located adjacent each other and are complementally mounted relative to friction roller 20 and pulley wheel 22, respectively. A nonextensible pulley belt 38 engages grooves 44) and 42, respectively, of

pulley Wheels

22 and 34.

As best shown in FIGURES 1, 2 and 3, a control arm 44 is also pivotally mounted on stud shaft 26,

stops

46 and 48, located on housing 10, limiting the movement of arm 44 to the arc described therebetween. A suitable detent 50 biased by spring 51 is carried by housing 10 and co-operates with spaced

perforations

54a, 54b, 54c of arm 44 to provide discrete locations for FORWARD, STILL and REVERSE

control positions

56a, 56b and 560, respectively of arm 44. Control arm 44 includes a downwardly extending portion 52 which overlaps arm member 24 and which carries, at its lower end, a lug 5S projecting therefrom substantially parallel to the axis of stud shaft 26. A spring wire member 60 formed with a loop 62 and crossed

leg members

64 and 66 is mounted on stud shaft 26 intermediate arm member 24 and control arm 44. A spacer 68 mounted on stud shaft 26 accommodates loop portion 62 of spring member 60. The

crossed leg members

64 and 66 of spring member 60 lie against opposite sides of lug 58 of control arm 44 and, adjacent their lower ends, engage

pins

70 and 72 located on arm member 24 and projecting therefrom adjacent driven member 30.

As best shown in FIGURES 1, 2 and 3, a power output pulley 74 is secured to a shaft 76, which shaft is preferably separate from but coaxial with stud shaft 26. Shaft 76 is arranged to be operatively connected, by means not shown, to the moveable elements of the motion-picture apparatus such as drive sprockets, shutter, take-up reels and the like which are not shown. An elastic belt 78 interconnects output pulley 36 of driven member 30 and power output pulley 74. As power output pulley '74 is mounted on substantially the same axis as arm member 24, any pivotal movement of arm member 24 about stud shaft 26 will not materially affect the tension in belt 78.

In operation, control member 44 is preferably first positioned in STILL position 56!), as best shown in FIG.

' 1. When the electrical circuit (not shown) for electric motor 12 is completed the motor will rotate drive member 18 in a counterclockwise direction, but, as

friction rollers

20 and 32 are spaced from each other and as the pulley belt 38 loosely connects

pulley wheels

22 and 34 so as to impart no rotation, the driven member 30 is not rotated.

To obtain forward projection with the motion-picture apparatus, control arm 44 is moved downwardly to the FORWARD position 56a. Detent 50 will seat itself in perforation 54a so as to retain control arm 44 in this position as shown in FIG. 4. Lug 58 will thus be arcuately displaced a proportionate distance about stud shaft 26, and as it bears against leg member 64 of spring wire member 60, will cause the spring wire member 60 to move in a counterclockwise direction on spacer 68 about stud shaft 26. This movement will cause the leg 64 of spring member 60, by virtue of its engagement with pin 70, to move arm member 24 in a counterclockwise direction about stud shaft 26 until, as shown in FIGURES 3 and 4, the pulley belt 38 becomes taut. However, at this time control arm 44 has not reached it FORWARD position 56a While in the embodiment illustrated the diameter of v the friction roller 29 relative'to the diameter of friction and the added movement required for this arm to reach i ficient to insure nonslippage, and does not applya tension to the belt which isso great as toproduce abnormally h gh friction forces such as would require an electric motor 12 of increased horsepower. Unidirectional rotation of drive member 18 in a counterclockwise direction 38 and keep it under a predetermineddrive tension suf- I is thus coupled to driven member 30 to rotatedriven member 30 in the forward direction shown by arrow F.

Hence, as driven member 30 is always drivingly coupled 'by elastic belt .78 to power output pulley 74, rotation of 'dIlVGll member 30 willbe transmitted to power output pulley'74, and, as. shown in FIG. 3, will cause the latter to be rotated in the direction shown by the arrow F If, now, the reverse direction of'operation is desired, the control arm 44 is moved through the STILL position 56b to the REVERSE position 56c, wherein detent 50 is positively seated in perforation 540. In moving control arm 44 to the REVERSE position 56c,'-1ug158 bears against leg 66 of spring member 60, and by virtue ofits I engagement with pin 72, will move arm member 24 in a clockwise direction about stud shaft 26, until as shown in FIG. 5,

friction rollers

20 and 32 are in engagement. As was described hereinabove relative to the FORWARD- postion 56a, control arm44 has not reached its REVERSE positon 560 when friction rollers 20' and 32 are first fric tionally engaged. The added movement required for arm 44 to reach the REVERSE position 56c causeslug 58 to deform leg 66 of the spring and bias the same so that it tends to force arm 24 in a clockwise direction. This bias of spring leg 66 thus tends to increase the pressure between

friction rollers

20 and 32 and keep them in contact under a predetermined force sufficient to insure nonslippage, and yet not so great as to produce abnormally high friction forces.

Friction rollers

20 and 32 of drive mem- :ber 18 and driven member 30, respectively; are thu drivingly coupled as shown in FIG. 5 to rotate driven mem- I ber in a clockwise or reverse direction. Pulley belt 38, under these conditions is loose and slips freely, on pulley.

wheels 22 and34 of drive member 18 and driven member 7 '30, respectively. Hence, the unidirectional rotation of drive member 18 is thusdrivingly coupled by driven member 30 and elastic belt 78 to power output pulley Z4 for rotation in a clockwise or reverse direction (opposite to direction F shown in'FIG. ,4).-

It is to be particularlynoted that in the drive mechanism described hereinabove 'controlarm 44 is resil .iently interconnected to arm member 24 by spring 'wire member 60. Moreover the length of belt 38' is so selected that it vwill stop the actual counterclockwise movement .of arm member 24 before control arm 44 has reached its' sov FORWARD position, so that fur'ther movement of arm 44 will deform spring arm 64 and bias or load it so that'it will tend to move the drive means .further in a counterclockwise direction. This bias or load build up in spring arm 64 will produce a predetermined drive tension in the,

belt, suflicient to insure nonslippage, and yet'not so great;

arm 24 as is described roller 32 is in the same ratio as the diameter of pulley wheel 22 to' pulley wheel 34 and, hence, the rotational speed of driven member'3r0'is the same in theFORWARD andREVERSE positions of control arm 44, "this is a matter of choice and any desired speed ratios could beobtained by proper selection of pulleys and/or'friction rollers without affecting the principle of operation;

Further, it will be obvious that changes can be made in the foregoing construction without departing from the spirit and scope of the invention. A single leaf spring secured'to thecontrol arm 44 and supporting the driven 'member 30 could in the simplest construction be substituted for'spring member 60and arm 24. Similarly, a U- shaped hairspringgas well as helical compression and/or tension springs, could be substituted for spring member 60 to obtain the desired bias or spring load acting on hereinabove relative to the embodiment shown. I a

The invention has been describ-edindetail with particular reference to a preferred embodimentthereof,;but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinaboveiand as defined in the appended claims. 7

We claim: a v. 1. .In a reversible drive mechanism comprising:

(a) a unidirectional drivemeans including a first friction roller. and affirst pulley wheel coaxially arranged for rotation in the same predetermined direction; I a p 7 (b) a driven means including a second friction roller and a second pulley wheel vcoaxia lly arranged for rotation so that said first and second friction rollers and'said first and second pulleywheels lie in common planesrof rotation; v

(1) means for mounting said driven means to move between afirst position wherein said first and said secondfriction rollers are in rolling engagement, and a second position wherein said first and said second friction rollers are' disengaged;

(c)'-a drive belt embracing said first and second pulley wheels and of such length that in said second position of said driven means it drivingly couples said first and second pulley wheels, and, in said first position of said driven means it uncouples said first and second pulley wheels; 7 H a V a V v (d) control means forselectively moving said mountingmeans for said driven means between said two positions; the improvement which comprises: 7 ('1) means for resiliently connecting said mounting meansfor said driven means tosaid control means whereby there is an {oventravel between V the two which biases, said driven means past said first and second positions when said control means is moved into corresponding ones of said twoloca-tions. v ;;2.-A reversible drive mechanism comprising: (a) a drive means including a first friction roller and a first pulley 'wheel-coaxiallyarranged for rotation in thesame predetermined direction; (b) an arm' member mounted for swinging movement relative to said drive means in a plane substantially perpendicular to the axis of rotation of said drive means; I

(c) a driven means mounted on said arm member for movement therewith toward and away from said drive means and including a second friction roller and a second pulley wheel coaxially arranged for rotation so that said firstand second friction rollers and said first-and second pulley wheels lie in common planes of rotation, respectively;

v (d) a control member pivoted about an. axis for swinging movement in a plane substantially parallel to that of said arm member and adapted for selective movement between three discrete positions which include:

(1) a first position for drivingly coupling said first friction roller of said drive means and said second friction roller of said driven means for rotation of said driven means in one direction;

(2) a second position wherein said driven means is uncoupled from said drive means; and

(3) a third position for drivingly coupling said first pulley of said drive means to said second pulley of said driven means for rotation of said driven means in the opposite direction;

(e) a drive belt embracing said first and second pulley wheels and of such length that in said third position of said control member said drive belt frictionally drivingly couples said first and second pulley wheels and in said first and second positions of said control member said drive belt uncouples said first and second pulley wheels, respectively;

(f) a lug member carried by said control member and radially spaced from the axis of rotation thereof for movement therewith; and

(g) a spring member interposed between said arm member and said control member including a pair of resilient legs radially extending from said pivot axis of said control member;

(1) free end portions of each of said legs secured to said arm and intermediate portions of each of said legs positioned on opposite edges of said lug for engagement therewith to resiliently connect said arm member to said control member whereby selective movement of said control member toward either of said first and third positions initially drivingly couples said driven means to said drive means so that overtravel of said control member to said first and third discrete positions biases said spring member to to hold said driven means in coupling engagement with said drive means.

3. A reversible drive mechanism comprising:

(a) drive means adapted to be rotated in a predetermined direction;

(b) driven means mounted for movement toward and away from said drive means between a first position, wherein it is drivingly coupled to said drive means for rotation in a first direction, and a second position, wherein it is drivingly coupled to said drive means for rotation in the opposite direction;

(0) a control member pivotally mounted to move between two locations;

(d) means connecting said control member to said driven means for selectively moving said driven means to a corresponding one of said two positions as said control member is moved from one to the other of said two locations, and including,

(l) a log member radially spaced from the pivotal axis of, and fixed to, said control member for movement therewith;

(2) a wire spring member having a pair of elongated legs extending substantially radially from the pivot point of said control member, and arranged so that opposite edges of said lug member are engaged by opposite ones of said legs at a point intermediate the length thereof,

10 and (3) means for connecting each of said legs to said driven means at a point spaced from the point at which said legs engage said lug member to provide a resilient connection between said control member and said driven means which is biased in a direction to urge said driven means past either of said first and second positions when said control member is moved to either of said two locations.

4. A reversible drive mechanism comprising:

(a) drive means adapted to be rotated in a predetermined direction;

(b) driven means mounted for movement from 21 normal neutral position, wherein it is disconnected from 25 said drive means, toward and away from said drive means between a first position, wherein it is drivingly coupled to said drive means for rotation in one direction, and a second position wherein it is drivingly connected to said drive means for rotation in the opposite direction;

(0) actuating means for selectively moving said driven means from said neutral position to either of said two positions and thereafter resiliently urging said driven means into driving engagement with said drive means, and including (1) a shift lever oscillatable from a neutral position to either of two locations corresponding to said two positions of said driven means; and

(2) means for selectively resiliently connecting said shift lever to said driven means only when said shift lever is moved toward one of said two locations from its neutral position to provide an over-travel between said shift lever and said driven means which biases said driven means past said first and second positions when said shift lever is moved into corresponding ones of said two locations.

References Cited by the Examiner UNITED STATES PATENTS 1,601,530 9/26 Ireland et a1. 74-203 2,677,432 5/54 Ronning 74402 x 2,831,357 4/58 Davies 74 2os BROUGHTON G. DURHAM, Primary Examiner.

Claims

1. IN A REVERSIBLE DRIVE MECHANISM COMPRISING: (A) A UNIDIRECTIONAL DRIVE MEANS INCLUDING A FIRST FRICTION ROLLER AND A FIRST PULLEY WHEEL COAXIALLY ARRANGED FOR ROTATION IN THE SAME PREDETERMINED DIRECTION; (B) A DRIVEN MEANS INCLUDING A SECOND FRICTION ROLLER AND A SECOND PULLEY WHEEL COAXIALY ARRANGAED FOR ROTATION SO THAT SAID FIRST AND SECOND FRICTION ROLLERS AND SAID FIRST AND SECOND PULLEY WHEELS LIE IN COMMON PLANES OF ROTATION; (1) MEANS FOR MOUNTING SAID DRIVE MEANS TO MOVE BETWEEN A FIRST POSITION WHEREIN SAID FIRST AND SAID SECOND FRICTION ROLLERS ARE IN ROLLING ENGAGEMENT, AND A SECOND POSITION WHEREIN SAID FIRST AND SAID SECOND FRICTION ROLLERS ARE DISENGAGED; (C) A DRIVE BELT EMBRACING SAID FIRST AND SECOND PULLEY WHEELS AND OF SUCH LENGTH THAT IN SAID SECOND POSITION OF SAID DRIVEN MEANS IT DRIVINGLY COUPLES SAID FIRST AND SECOND PULLEY WHEELS, AND IN SAID FIRST POSITION OF SAID DRIVEN MEANS IT UNCOUPLES SAID FIRST AND SECOND PULLEY WHEELS; (D) CONTROL MEANS FOR SELECTIVELY MOVING SAID MOUNTING MEANS FOR SAID DRIVEN MEANS BETWEEN SAID TWO POSITION, THE IMPROVEMENT WHICH COMPRISES: (1) MEANS FOR RESILIENTLY CONNECTING SAID MOUNTING MEANS FOR SAID DRIVEN MEANS TO SAID CONTROL MEANS WHEREBY THERE IS AN OVERTRAVEL BETWEEN THE TWO WHICH BIASES SAID DRIVEN MEANS PAST SAID FIRST AND SECOND POSITIONS WHEN SAID CONTROL MEANS IS MOVED INTO CORRESPONDING ONES OF SAID TWO LOCATIONS.