Mechanical positive driving system

Aug. 10, 1937.

w. g. h. finch 2,089,846

MECHANICAL POSITIVE DRIVING SYSTEM

Original Filed Feb. 26, 1936 4 Sheets-Sheet 1

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3iwentor

WILLIAM GH. FINCH

<img file="US2089846A_D0002.tif" />

attorney

Aug. 10, 1937. w. g. h. finch 2,089,846

MECHANICAL POSITIVE DRIVING SYSTEM

Original Filed Feb. 26, 1936 4 Sheets-Sheet 2

<img file="US2089846A_D0003.tif" />

Gttorney

Aug. 10, 1937

W. &lt;5. H. FINCH

2,089,846

MECHANICAL POSITIVE DRIVING SYSTEM

Original Filed Feb. 26, 1936 4 Sheets-Sheet 3

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<img file="US2089846A_D0005.tif" />

<img file="US2089846A_D0006.tif" />

3nrentor

WILLIAM G.H. FINCH

<img file="US2089846A_D0007.tif" />

dttorneu

Aug. 10, 1937.

w. g. h. finch. 2,089,846

MECHANICAL POSITIVE DRIVING SYSTEM

Original Filed Feb. 26, 1936 4 Sheets-Sheet 4

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<img file="US2089846A_D0009.tif" />

WILLIAM G.H. FINCH

Attorney

Patented Aug. 10, 1937

2,089,846

UNITED STATES PATENT OFFICE

2,089,846

MECHANICAL POSITIVE DRIVING SYSTEM

William G. H. Finch, Spuyten Duyvil, N. Y.

Original applications February 26,1936, Serial No. 65,869, and April 6, 1936, Serial No. 72,991. Divided and this application December 30,1936, Serial No. 118,191

Claims. (Cl. 192—27)

This invention relates to novel apparatus for substantially instantaneously connecting and disconnecting a driven member from a driving member, together with novel means for compensating 5 for inertial displacements due to the connections and disconnections.

This application is a division of the parent application Serial No. 65,869, filed February 26, 1936, which matured into Patent No. 2,047,863, 10 entitled “Telecommunications system”, and is a division of my copending application, Serial No. 72,991, filed April 6, 1936 and entitled “Telepicture synchronizing system.”

In the transmission of pictures to remote 15 points, it is essential that the receiver picture drum be in phase synchronism with the transmitter drum. Many attempts have been made to attain such phase synchronization. It is extremely desirable to provide a positive driving 2Q connection between the motor and the revolving drum to avoid any deleterious effects due to frictional coupling. In my Reissue Patent No. 19,575, I have disclosed a system for connecting and disconnecting the positive driving connection be25 tween the driving motor and the drum in response to synchronizing signals to maintain phase synchronization.

In my present invention, I utilize an overrunning or positive clutch for maintaining the 30 drum in phase synchronism. To overcome the effects of rotational inertia present in a large ! telepicture system having a large revolving drum, I provide a flexible mechanical coupling between the positive clutch and the receiving drum. This 35 coupling is designed to permit a momentary phase displacement of the drum due to accelerating or decelerating inertial forces acting on the drum during the substantially instantaneous connection and disconnection thereof from the 40 driv fig motor. . The flexible coupling is further designed to promptly automatically compensate for these momentary phase displacements.

This compensation is accomplished by mechanical means of a positive nature, to bring 45 the driven member or drum back to the position it had at the instant of connection or disconnection. The flexible connection can accordingly be considered as a member in a mechanical positive driving connection between the motor and 50 the drum since no rubber, fluid or other relatively elastic connection is used. Elastic connections are undesirable for picture work since any tendency to “set” will distort the picture reproduction.

It is accordingly an object of my present in vention to provide a novel driving system employing an over-running or positive clutch connection to the driven member.

Another object of my invention is to provide a mechanical flexible coupling in the positive 6 drive for a rotatable member, which automatically compensates for any momentary phase displacement due to acceleration or deceleration forces.

A further object of my invention is to provide 10 a novel combination of a positive clutch engaging and disengaging means for a revolving member and a positive driving connection to permit substantially instantaneous connection and disconnection of the member. 15

Other objects of my Invention together with the foregoing will become apparent in the following description in connection with the drawings, in which:

Figure 1 is a plan view of a preferred embodi- ₂o ment of the telepicture receiver.

Figure 2 is an enlarged cross-sectional view through the receiver drum and drive of Figure 1.

Figure 3 is a cross-sectional view taken through Figure 2 showing a partially enlarged plan view 25 of the drive mechanism and clutch trip levers.

Figure 4 is a perspective disassembled view of the clutch mechanism.

Figure 5 is a cross-sectional view illustrating a fragmentary detail of the internal clutch roller 30 assembly.

Figures 6, 7 and 8 are cross-sectional views taken respectively along 6—6, 7—7 and 8—8 of Figure 2 showing details of the synchronizing clutch control mechanism. 35

Figure 9 is a modification of the synchronizing clutch control mechanism corresponding to Figure 7.

Figure 10 is a cross-sectional view along 10—10 of Fig. 9. 40

Referring to Figure 1, the telepicture receiver is mounted on a cast iron base 11 if it is designed for non-portable use. Synchronous motor 12 drives the receiver drum 13 through the overrunning clutch 14 and suitable gearing contained 45 in housing 15. Synchronous motor 12 is connected by leads 16 to electrical supply lines 17 for electrical energization thereof. Reduction gearing 18 connects worm or feed screw 19 to spindle end 20 rotating with drum 13. If drum 50 13 rotates 100 revolutions per minute and 100 scanning lines per inch are used, the pitch of worm 19 and its rate of revolution will be designed to advance receiver carriage 21 at the rate of one inch per minute so that the scanning 55

2,089,846 set in the spindle 42. It is to be understood that the coupling member 63 is slidable axially on the spindle 42 and that this coupling member 63 provides the driving connection for the spindle 42 since no relative angular movement there- 5 between is possible.

Accordingly, when the overrunning clutch 14 is engaged the motor drive 12 is transmitted by the worm and pinion 36—37, the engaged clutch 14 and the coupling member 63 to the spindle 42. io The face plate driver 66 is rigidly mounted on the spindle 42 by pin 67. A projection or key 68, on the face 69 of the face plate driver 66, sets into a corresponding groove in the end plate 46 of the receiver drum 13. A positive driving connection 15 is accordingly had between the motor 12 and the receiver drum 13 when the positive or overrunning clutch 14 is engaged.

A set of pins 70 project from the opposite end 71 of the face plate driver 66 to press the coupling 20 member 63 into engagement with the V notches 61 of the cam plate 51. Springs 72 press the pins 70 against the face 73 of the coupling member 63. A positive driving connection of coupling member 63 with cam plate hub 60 is had for all 25 practical purposes in the operation of the system, since the pins 70 maintain the engagement of V projection 62 and V grooves 61 during the driving cycle of the drum.

An important feature of my present invention 30 resides in the automatic connection and disconnection of the positive or overrunning clutch 14 to maintain the revolving receiver drum 13 in phase synchronism with the transmitter drum (not shown). In my Re. Patent No. 19,575, is 35 described one method for connecting and disconnecting the positive drive from between the source of motive power and the revolving drum. My present invention embodies the principle of the overrunning clutch in an instantaneous syn- 40 chronization mechanism. Synchronization according to Re. Patent No. 19,575 depends upon the actuation of a pawl engaging a ratchet wheel in the positive driving connection. The limits of phasing positions are accordingly within the pitch 45 or width of one tooth of the ratchet wheel.

By employing an overrunning clutch, the positive drive is had during the rotation of the drum 13 and accurate phase synchronization is feasible at any point in the circumferential movement of 50 the drum. The stop plate 54 contains the pins 55 which coact with the wedging rollers 53. When the cam plate 51 is driven by the clutch ’ driver 40 during the wedging action of the rollers 53, the stop plate 54 is also driven and revolves 55 with the cam plate 51. However, I provide a notch 74 on the periphery of the stop plate 54 ' which is engageable with a projection 75 on trigger lever 76 (Figure 7) which is mechanically biased by spring 77 toward the stop plate 54. 60

Figure 7 illustrates the engagement of lever, projection 75 with the corresponding notch 74 in the stop plate 54. In this position the stop plate is prevented from further rotating counterclockwise, as indicated by the arrow. The pins 55 ac- ⁰⁵cordingly abut the rollers 53 within the overrunning clutch J 4 and force the rollers 53 against the plungers 58 to disengage the clutch 14, as will be understood by those skilled in the art. The rollers 53 are moved along the inclined surfaces 57 releasing the wedging action of the rollers 53 from between the cam plate 51 and the inner clutch driver surface 56. The motor 12 continues to rotate the clutch driver 40 but the driv- 75 of the film 22 mounted on drum 13 will progress in a continuous helical path. The light beam 23 emanating from focusing system 24 in this example Is designed to be .01 of an inch in width 5 to prevent translation overlapping. Carriage 2f houses the receiver electro-optical system and rides on V-tracks 25 and 26 with V-rollers 27 and 28.

The record sheet 22 is clamped upon drum 13 10 by clamping members 30. A scale is marked upon the drum in the “under-lap” portion to indicate the length of the record sheet being used. The plurality of roller sections 31 are shown out of position and are used to aid in smoothly mount15 Ing record sheet 22 on drum 13 in a manner described in the parent application already referred to. Drum 13 is rotatably supported by pointed spindle 32 supported in tail stock 33.

Figure 2 is the cross-sectional view of Figure 20 1 through the axis of drum 13, illustrating in detail the mechanism for driving and mounting drum 13. The shaft 34 driven by the motor 12 through the flexible coupling 35 rotates worm 36 which drives worm gear 37. The hub 38 of worm 25 gear 37 is connected to the clutch driver 40 by projections 41 of the hub 38 into corresponding grooves in the clutch driver 40. The worm gear 37 and the clutch driver 40 are free to rotate upon the spindle 42. The housing 15 encloses the worm 30 and pinion drive and contains bearing 41 which supports one end of the spindle 42. The opposite end 44 of spindle 42 is conical and coacts with the metallic insert 45 pinned to end plate 46 of drum 13 by pin 47, and supports drum 13. Me35 tallic insert 47 attached to opposite end plate 43 coacts with the conical end 43 of the· spindle 32 supported in tail stock 33. Hollow shaft 50 rigidly connects the metallic inserts 45 and 47. Drum 13 is accordingly rotatably supported by 40 the conical ends 44 and 49.

Figure 4 is a perspective illustration of the overrunning clutch 14 disassembled to more clearly explain its operation. The clutch cam plate 51 is rotatably mounted within the clutch driver 45 40 upon spindle 42 (shown in dotted). There are four openings 52 on the surface of the cam plate which contain metal cylindrical rollers 53. The clutch stop plate 54 is fitted adjacent to the cam plate 51 and contains four pins 55 which 50 coact with the cylindrical rollers 53.

Figure 6 is a sectional view through the overrunning clutch 14 taken along 6—6 of Figure 2 illustrating the character of the recesses 52 in the cam plate 51. The principle of the overrun55 ning clutch Is well known in the art. The rollers 53 are wedged between the inner surface 56 of the clutch driver 40 and the inclined surfaces 57 of the recesses 52. Plungers 58 set in cam plate 51 are forced against each roller 53 by springs 59 60 set within the cam plate 51. The wedging action of the rollers 53 between surface 56 and inclined ; surfaces 57 serves as a positive connection between the clutch driver 40 and the cam plate or clutch driven member 5t.

Figure 5 is a cross-sectional enlarged detailed view illustrating the arrangement of a roller 53 and its stop plate pin 55 within a recess 52 of the cam plate 51 in engaged position where the plunger 50 is pressed against the roller 53 by 70 spring 59 set in the cam plate 51.

Referring to Figures 2 and 4, the hub 60 of cam plate 5i has a V notch 61 at one end thereof which coacts with a V projection 62 on the coupling member 63. Coupling member 63 has key75 ways 64 that slidably engage corresponding keys

2,089,846 ing of the drum 13 therefrom is instantaneously discontinued.

A pawl 80 is mechanically biased toward the stop plate 54 by spring 81. Pawl 80 projects into 5 a notch 02 on the periphery of stop plate 04 at the instant the projection 75 of the trigger lever 76 engages the notch 74 in the stop plate 84^ The pawl 80 accordingly prevents rebound of the stop plate when its notch is arrested, thus 10 insuring a positive disengagement of the overrunning clutch 14.

Figures 3, 7 and 8 illustrate one modification for actuating the clutch 14 in response to synchronizing signals. For rapid engagement of the 15 overrunning clutch 14 in response to synchronizing signals, falling weight 83 is caused to impact the end 84 of the trigger lever 76, removing the projection 75 from the notch 74 in the stop plate 54 and permitting the plungers 88 to wedge 20 the rollers 53 between the cam plate 51 and the clutch driver 40. The movement of weight OS is guided by post 85 through a hole in the center of the weight 83.

Figure 7 illustrates the weight in its upper 25 position. A projection 86 on the armature 87 of the synchronizing magnet 88 holds the weight 83 in its upper position in readiness for release. When a synchronizing impulse is impressed upon magnet 88 through its leads 88—88 in a 30 manner well known in the art and described in detail in the parent application, the armature is attracted toward the magnet 88 against the spring 91 permitting the weight 83 to drop and Impact the end 84 of trigger lever 76 to drivingly 35 engage the clutch 14 as illustrated in Figure 8.

The weight 83 is replaced to its upper position by means of the lever 92. A pin 84 projects from the surface of the stop plate 54 and once per revolution of the stop plate, the pin 84 40 presses the end 93 of lever 92 downward so that the opposite end 95 automatically raises the weight 83 to its upper position shown in dotted in Figure 8. Spring 91 moves the armature 87 away from the magnet 88 permitting the projec45 tion 86 to engage the bottom corner of the weight 83 to hold it in its upper position in readiness for its cyclical release. Figure 3 is a sectional view through Figure 2 showing the driving connections from the motor coupling 38 and is a 80 plan view of the synchronizing levers 76 and 82, weight 83 and magnet 88.

The receiver drum 13 is maintained in phase synchronism by means of cyclically transmitted synchronizing signals during the underlap 65 period of the transmitter drum (not shown). The receiver synchronizing cam i 00 is mounted at the end 20 of the spindle 42 outside the housing 15 clearly illustrated in Figure 2. The subtended angle of the cam nib 101 may be made 60 equal· to the corresponding subtended angle of the underlap portion of the receiver drum 13 so that the receiver synchronizing switch 102 will be maintained open during this interval to cause synchronizing magnet 88 to be connected in the 45 circuit of the receiver amplifier output as described in the parent application.

As there described, the amplifier is a class B amplifier and the tubes are biased to “cut off”, so that when no signal is Impressed in the input 70 circuit, zero plate current will flow and the synchronising magnet 88 connected therein win not be energized until the synchronizing impulse is impressed. In my preferred embodiment, the synchronizing impulse is of a magnitude greater 75 than the largest telepicture signal so that the synchronizing magnet will respond only to the synchronizing signals.

The parts of the receiver drum 13 are preferably made of aluminum to reduce its rotational inertia. The coupling member 83 coacting with ₆the driven cam plate 51 of the overrunning clutch 14 acts as a shock absorber to resist the inertial resistance of the drum 13 during its starting from rest to synchronous speed, or of any inertial forces it may present during the io synchronizing action.

When there is a tendency for the cam plate li to advance in phase with respect to the coupling member 83, the coupling member will slide axially along the spindle 42 away from the clutch 15 cam H and against the pressure of the pins 70 mechanically biased by springs 72. The V notches 61 of the cam hub 66, coacting with the V projections 62 of the coupling member 68, effects a positive driving action between the two 20 when they are in engagement. A relative motion between the cam plate 81 and member 68 causes its V projection to slide away from the V notches 61 proportional to the forces tending to resist their in-phase movement. Such forces 25 occur momentarily, and the coupling member 68 is again forced into normal engagement with the v notches 61 by the pins 71.

Any momentary relative movement between the dutch driven member II and the member 63 30 is automatically compensated by the return of the V projections 62 into normal engagement with the V notches 61. A spring III connects an eyelet pin ill secured in the coupling member IS and another eyelet pin 117 secured in 35 the hub II of the cam plate II, as illustrated in Figures 7 and 8. Spring III facilitates the automatic return engagement of the V projection 12 in the V notches II of the corresponding members. 40

Since the coupling member II is slidably keyed or splined to the spindle 42 and the face plate driver 81 is rigidly keyed to the spindle 42, the reedver drum 13 is driven positively from the coupling member 13. The source of motive 45 power 12 is connected positively to the dutch driver 41 as already described. When the dutch 14 is engaged, a further positive connection is had between the clutch driver 41 and the cam plate If, by the wedging action of the rollers IS. 50 The v connection between the hub 86 of cam plate If and the coupling member 8| is in effect a flexible positive coupling.

When the projections 62 normally engage notches II, the source of motive power 12 drives 55 the receiver drum II through a positive driving connection. The relation of the hub 16 and coupling member 13 as already described is a flexible positive connection since it permits momentary changes in phase, but automatically returns to 00 the normal phase relation. The synchronizing apparatus operating on the dutch stop plate 14 disconnects the positive driving connection between the source of motive power 12 and the receiving drum 13 at the positive or overrunning 05 dutch 14 if the receiver drum 13 is not in phase synchronism with the transmitter drum (not shown).

It is to be understood that the receiver drum 13 rotates in synchronism and in phase with the 70 corresponding transmitter drum, and that the carriage 21 simultaneously advances the impinging signal light beam 28 axially along the film 22 mounted on the drum 18 to record the picture bdng transmitted. The intensity of the light 75

2,089,846 beam 23 sharply focused upon the film 22 varies in accordance with the shading of the picture being transmitted as is evident to those skilled in the art.

A modification of the synchronizing magnetclutch trigger arrangement is illustrated in Figure 9 corresponding to Fig. 7. The synchronizing magnet HO corresponding to magnet 88 is mounted on a bracket 111 below the surface 112 of the base II. The poles 113 of the synchronizing magnet HO project through the surface H2 to coact with the armature plate 114 attached to the end 115 of the trigger lever 76.

Figure 10 is a cross-sectional view through 15 the magnet HO illustrating how the armature plate 114 is arranged above the two poles 113—H 3 of the electromagnet 110 and how the trigger end H5 is positioned between the poles 113—113. The trigger 76 is accordingly directly actu20 ated by the synchronizing magnet 110 without the use of a falling weight 83 as in the hereinabove described modification. While the clutch 14 and stop-plate 54 are rotating, the lever 76 will be held in the dotted position of Fig. 9 so that 25 the armature plate 114 will be close to the poles II3 of the magnet H O. The peripheral surface of the stop-plate 54 will abut the trigger projection 75 and press the lever 76 toward the poles H3 against the action of the biasing spring 77. The 30 armature plate 114 will accordingly be close to the poles H3 of the magnet HO during the major portion of the revolution of the stop-plate 54, but will tend to be moved away under the action of spring 77 when the notch 74 comes in engaging 35 position with the projection 75 of the trigger 76.

If the drum 13 is in phase synchronism, the synchronizing impulses will arrive at the synchronizing magnet 111 through leads H6—117 in time to hold the trigger 76 away from engage40 ment with the stop-plate notch 74 and permit the drum 13 to continue in phase synchronism. It is to be understood that if the drum 13 is out of phase synchronism, the notch 74 will engage the trigger projection 75 to disengage the positive or overrunning clutch 14. When the synchronizing signal is received by the magnet HO, the stopplate 54 is released and the clutch reengages to rotate the drum in proper phase synchronism.