US1656962A - Synchronizing mechanism - Google Patents

Description

Jan. 24, 1928. 1,656,962

E. A. SPERRY SYNCHRONIZING MECHANISM Filed Sept. 18. 1920 53 woe/M4101 Patented Jan. a4, 1928.

v 1,656,962 PATENT OFFICE.

ELMER A. SPERRY, OF BROOKLYN, NEW YORK, ASSIGNOR TO THE SPEBRY GYROSGOPE COMPANY, OF BROOKLYN, NEW YORK, A CORPORATION OF NEW YORK.

SYNCHBONIZING- MECHANISM.

Application filed September 18, 1920. Serial No. 411,819.

This invention relates to means for maintainingsynchronism between a plurality of movable members. More particularly it is concerned with the provision of reliable and eiiicient means for insuring the driving of a member at a constant speed and in synchronism with a constant speed device such as a clockwork mechanism. My invention will be found to be especially'useful when applied. to the constant speed rotation of telescopes in observatories, where, for example, it may be desired to cause constant speed rotation of'a telescope through one revolution per day. However, it will be apparent that my invention is of general application and may be employed wherever it is desired to maintain one member in synchronism with another.

Further objects and advantages will ap-- pear as the description of the invention is hereinafter developed.

Referring to the drawings wherein I have shown what I now consider to he the preferred form of my invention:

Fig. 1 is a view in elevation of the synchronizing mechanism, parts being broken away.

Fig. 2 is a view in sectional elevation taken on line 2-2 of Fig. 1.

Fig. 3 is a view of a detail.

Fig.4 .is a view in elevation showing the mechanism of Fig. 1 applied to a driven member for controlling the speed thereof, certain parts appearing in section.

Fig. .5 is a wiring iagram. Fig. 6 is a detail showing a different p0- sition of the parts shown in Fig. 1.

The driven member 1 is shown mounted on a shaft -2 which may be rotated by any suitable means. For purposes of illustration I have'shown said shaft as driven by a motor 3, through the medium, of a shaft 4, worm 5, and worm wheel 6. It will, of course, be understood that motor 3 can drive, through worm wheel 6 or otherwise, a telescope or any other device which it may be desired to rotate at a definite and constant speed. For maintainin constant the speed of motor 3, and hence o the members driven thereby, a speed responsive governor may be provided comprising a pair of weighted arms 7, 7 fixedly connected at one end each to shaft 4, and at their other ends to a sleeve 8 slidable on said shaft 4. Said sleeve 8 has attached thereto a conta t. 9

winding 16. Aresistance 17 is in series with armature 15 and is connected at its terminals with contacts 9 and 10 as shown in Fig. 5. In this manner, said resistance isshort circuited when contact *9 engages contact 10, and is placed in series with the armature 15 when said contacts are separated. By this means, as will ,be readily understood, the speed of rotation of shaft 4 is kept constant. Obviously, the position of contact 10 determines the normal speed of the motor, for exam le, the more it' is moved to the right in ig; 4, the h gher the normal speed of the motor, since a greater speed must be attained to cause the governor to separate contacts 9 and 10 to cut in the resistance 17 The operation of this device is obvious, for the position of contact 10 determines the amount of bowing of springs 7 of the governor initially. As soon as the shaft 4 rotates, the weights carried by the leaf springs 7 would normally tend to fly outwardly and cause contact 9- to break away from contact 10, but this tendency of the weights to fly outwardly is opposed by the tension of springs .7 which is greater the more said sprmgs are bowed. The shaft 4 will therefore have to rotate at such a contact 9 is separated from contact 10. Ob-

viously, therefore; moving contact 10 to the right or left in Fig. 4, will give a greater or lesser initial bend or bowing to springs 7 and hence, a greater or lesser resistanceto the centrifugal force of the weights carried by said springs, so that the shaft 4 will have to rotate at greater orlesserspeed before said contact 9 is moved out of engagement with contact 10. i i

The driven member or arm 1 may be provided at one end with a trolley 18 adapted to traverse a circular track member 19 of insu latmg material and provided with contact members 20, 20'. Said track member 19 is shown mounted on a suitable support 21.

. Said contacts 20, 20 may be arranged in any suitable or desired manner on trackway 19, but for purposes of illustration I have shown them positioned diammetrically opposite each other on said trackway. It will be ap parent that as arm 1 is rotated through one revolution, trolley 18 is brought into engagement with said contacts 20 and 20 successively.

I prefer that the movement of arm 1 be kept in sy'nchronism with a master regulator 22 which may be an accurate clock, as shown. To this end I have shown contacts 23, 23 in the path of movement of the minute hand 24 of clock 22 and positioned similarly to contacts 20, 20'. By this arrangement if minute hand 24 and arm 1 are moving in synchronism, said minute hand will engage one of contacts 23, 23 at the same time that trolley 18 engages the corresponding one of contacts 20, 20. If, however, said minute hand and arm are not in synchronism, the minute hand will-engage one of contacts 23, 23 before or after trolley 18 engages the corresponding one of contacts 20, 20, In

.order to bring the parts driven by motor 3' into synchromsm with clockwork 22, so that they will be driven at the desired rate of speed, I have provided means brought into action when minute hand 24 and trolley 18 fail to engage their respective contacts simultaneously for moving the threaded member 25 to vary the position of contact 10 and thus change the slpeed of motor 3. Such means is shown in igs. 1-4, inclusive, and may be constructed substantially as follows:

Member 25 is threaded through a ratchet wheel 26 internall threaded to cooperate with the threads oi member 25, and having two sets of ratchet teeth, extending in op posite directions. Ratchet wheel 26 mounted between a pair of standards, 27, which standards support the member '25. Removable cap pieces 28 may be fitted over member 25 and secured to the standards 27, as shown. Rotation of member 25 in standards 27 may be prevented in any suitable manner, as by providing on member 25 a groove 29 designed to cooperate with a spline or key on one of cap ieces 28. In this manner it will be seen. t at rotation of ratchet wheel 26 in one direction or another will move member 25 longitudinally either backwardly or forwardly.

Pivot 11y mounted on cross piece 30 of the framew rk of the synchronizing mechanism is a member 31 provided at one end with a pendulum 32 and on opposite sides of its other end with 'armatures 33, 33' 'adapted .to cooperate respectively with solenoids or electromagnets 34, 34'. Between its pivotal connection and pendulum bob 32, the member 31 is provided with oppositely extending arms 35, 35' to which awls 36, 36' respectively,

are pivoted. Sai pawls, as shown, are designed to cooperate with the teeth of ratchet wheel 26 to move said wheel in one direction or another.

As shown in Fig. 5, electromagnet 34 is connected in circuit with contacts 23, 23', while electromagnet 34 is in circuit with contacts 20 and 20, said magnets being connected, through means to be described later, with one terminal of battery 50. Minute hand 24 and arm 1 are, as shown, connected with the other terminal of said battery. It

will now be seen that, if the minute hand 24 and arm 1 are moving in synchronism, so that said hand 24 and trolley 18 simultaneously engage corresponding contacts, mag

nets 34 and 34 will be energized -simultaneously and will have no effect on member 31 and pawls 36, 36. Suppose, however, that minute hand 24 engages contact 23 before trolley 18 engages contact 20. Magnet 34 is thereupon energized and armature 33 I attractedZto the left in Fig, 1. Pawl 36 is thereby moved to the right to turn ratchet wheel 26 clockwise. Turning of said ratchet wheel in said direction moves screw threadedretract threaded member 25, whereupon thev resilient member 11 will follow said member 25, being either normally biased into engagement therewith or suitably attached thereto, so that contact 10 will be moved to the left as viewed in Fig. 4 and decreased centrifugal force will suflice to disengage contact 9 from contact 10. The speed of motor 3 is thereby decreased.

Assuming that the minute hand 24 has engaged contact 23 before trolley 18 engages contact 20 and that ratchet wheel 26 has thereby been turned to move contact 10 to the left, it will be seen that some means must be provided for reventing movement of ratchet wheel 26 1n the opposite direction by the energization of magnet 34, when trolley 18 next engages contact 20. Without such means, the motor 3 would merely be momentarily speeded up when minute hand 24 engaged contact 23, and then, when trolley 18 engaged contact 20, the speed of said motor would be restored to its original value. In order to prevent this I. have provided means for retainin member 31 in the position to which it has been moved by one magnet until atter the other magnet has been 139 behind said pawls when the latter are moved from under their respective levers, I have shown said levers as provided with weights 38, 38'. Stops 39, 39' are provided to limit the downward movement of said levers. While various means may be provided for returning levers 37, 37 to their original positions after they have remained behind their respective pawls for a suflicient length of time, I prefer to utilize the following mechanism:

Pivoted to link 40 is an arm 41 which extends from said link to a point adjacent lever 37 as shown in Fig. 1. Said arm 41'is provided with a hooked extremity 42 and may be guided by a suitable bracket 43 attached to supports 13. Aspring44maybe attached to bracket 43 and'bear at one end against arm 41 to hold the latter normally in engagement with a pin or stop 45 carried by said bracket. Suitable endwise play is provided for arm 41 between pin 45 and the end of bracket 43 for a purpose which will appear later. The link 40 is pivoted as shown to standards 27 and rests normally on a pin 46 mounted in opposite supports 13. Said link 40 is provided with an armature 47 adapted to be attracted by an electroma'gnet 48 suitably mounted on one or more of said supports -13. Associated with lever 37 are elements similar to elements 40-48, inclusive,

and designated by the same numerals with a prime added. U V

As shown in Fig. 5, 'fnagnet 48' is in'circuit with magnet 34," while magnet 48 is in circuit with magnet 34. Assuming-now that minute hand 24 engages contact 23 before trolley .18 engages contact 20, magnets 34 and 48' will be energized. Pawl 36 isthereby swung to turn ratchet wheel 26 and when said pawl has reached the limit of its movement lever 37 drops upom pin 39 into the positiomshown in Fig.6, and prevents return of said pawl and of arm 31 to their original positions. Atthe' same time that .pawl 36 is moved, link 40 is; attracted by magnet 48 thereby moving arm 41' upwardly. Said arm, however, on engagin lever 37 will merely be pushed back in racket 43" a ainst spring 44'; suitable play being provi ed for said arm in said bracket as has been pointed out in connection with arm 41 and bracket 43. As soon as minute hand 24 passes out of engagement with contact 23, magnets 34 and 48' are'deenergized. Pendulum 32 cannot return pawl 36 and arm 31 to their original positions, however, since lever 37 has dropped behind said pawl. Link 40 and arm 41' will drop back to their original positions. Now, a moment or so later, when trolley 18 engages contact 20, magnets 34 and 48 are energized. However, since lever 37 is still behind pawl 36, arm

31 cannot move in.response to energization' of magnet 34, and hence ratchet wheel 26 is not moved. Arm 41 is moved upwardly by magnet 48, all parts finally assuming the position shown in Fig. 6, wlth hooked end 42 overlying lever 37. During movement of arm 41 past lever 37, of course, said arm was forced backwardly in bracket 43 when the beveled portion of end 42 engaged lever 37, but upon said beveled and clearing said lever, spring 44 snapped said lever into the illustrated position, as will readily be seen. Now, when trolley 18 passes out of engagement with contact 20, magnets 34 and 48 are deenergized, and arm 41 drops downwardly to its original position, thereby moving lever 37 from en agement with pawl 36. Pendulum bob 32 thereupon moves arm 31 and pawl 36 to their positions shown in Fig. 1. Arm 41,

lever 37, and pawl 36 thus assume their positlons shown in Fig. 1 and the synchronizing mechanism is ready for another cycle. If now, either magnets 34 and 48' or 34 and 48 should subsequently be energized, a similar cycle will occur. If desired, a spring 49 may be employed to assist in returning link 40 and arm 41 to their normal positions, and a similar spring49 may be employed in connection with link 40 and arm 41'. Springs 53, 53 may also be employed, as shown, to positively force pawls 36, 36' downwardly'into engagement with ratchet wheel 26.

In Fig. 5, I have shown thermotor 3 and magnets 34, 34, 48, 48 in circuit with a suitable source of E. M. F. such as a battery 50. If desired, means may be provided for automatically breaking the circuit in which the aforesaid magnets are located whenever motor 3 for any reason stops running. For this purpose'I'have shown in Fig. 5 a pair of contacts51 and 52 connected in the circuit from said magnets to battery ,50. Contact 51 is carried by resilient member l1,.as

moves backwardly a suflicient amount for resilient member 11 to bring contact 51 again into engagement with contact .52, so thatthe clock circuit is again rendered operative. As shown in Fig. when contacts 51, 52 are used, the member 25 may engage the resilient arm llat a point below contact 10, so that the pressure of the governor may spring arm 11 to open said contacts 51, 52.

The operation of my device will now be clear and may be briefly summarized as follows: As long as arm 1 and minute hand 24 move in synchronism, magnets 34 and 34' are energized simultaneously and the speed of motor 3 is not changed. If, however, the speed of the motor is not such as to drive arm 1 atexactly the speed of minute hand 30, one or the other of magnets 34, 34 will be energized to cause movement of contact and consequently change the speed of said motor. For example, if minute hand 24 engages contact 23 before trolley 18 engages contact 20, magnet 34 is energized and contact 10 is moved forward to increase the speed 0t said motor. Subsequent deenergization of said magnet 34, and energizationof ma net 34' by engagement 1 of trolley 18 wit 1 contact 20, does not change the speed of the motor but merely places the synchronizing mechanism in condition for another cycle. If, when minute hand 24 engages contact 23', trolley 18 is not in engagement with contact 20' the speed of motor 3 is again changed. In this way the speed of motor 3 is automatically maintained such as to drive member 18 in synchronism with minutehand 24. It is, of course, understood that motor 3 may be brought nearly to the desired speed by external means well known in the art and that the synchronizing means which -I have shown may then be em loyed to bring the motor exactly to the desired speed and maintain it automatically at such speed. For a given adjustment of contact 10 with respect to contact 9, the motor 3, of course,

runs at a constant speedand the speed responsive governor maintains such speed until said adjustment is changed by the synchronizing mechanism,

In accordance with the provisions of the patent statutes, I have herein described the principle of operation of my invention), together with the apparatus which I now consider to represent the best embodiment thereof, but I desireto have'it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means. Also, while it is designed to use the various features and elements in the combination and relations described, some of these may be altered and others omitted without interfering with the more general results outlined, and theinvention extends to such use.

Having described my invention, what I claim and desire to secure by Letters Patent vis: 4

1'. In combination, a plurality of rotatable members, contacts positioned at certain points in the respective paths of travel of said members, means brought into action by engagement of one of said members with its contact at a time when another of said members is disengaged from its corresponding contact for varying the speed of rotation of one of said members, and means brought into action by the subsequent engagement of said other member with its contact for restoring said first named means to its normal position without varying the speed of any of said members.

2. In combination, a motor, a member rotated thereby, a second rotatable member, means for maintaining said members ins 'nchronism, and means for rendering the rst mentioned means inoperative whenever the speed of said motor falls below a predetermined amount.

3. In combination, a .motor, a member rotated thereby, a second rotatable member, electrical means controlled by said members for synchronizing the same, and means for automatically rendering said electrical means inoperative whenever the speed of said motor falls below a predetermined amount.

4. In a synchronizing mechanism, in combination an adjustable member,-a movable element, means for moving said element in either of opposite directions, means res onsive to movement of said element for ad usting said member, means rendered operative upon movement of said element in elther of said directions for preventing return of said element to its normal position, and automatic means for rendering inoperative said preventing means.

5. A synchronizing mechanism comprising in combination an adjustable member, means including a movable element for adjusting said member in either of opposite directions, means for holding said element in a given position to prevent adjustment of said member for a given time, and means for automatically releasing said element.

6. In combination, a motor, means for varying the speed of said motor, means for preventing actuation of said first mentioned means for a given time, and means for automatically rendering said preventing means inoperative.

7. In a synchronizing device, a movable member, means for moving said member in one direction, means for moving said membeer in another direction, means responsive to .movement of said member in one direction for preventing return of said member to normal position, and means for automatically releasing said member after the means for moving said member in said other direction has been brought into operation.

8. In a synchronizing device, a movable member, an electromagnet for moving said member in one direction, a second electromagnet for moving said member in another direction, means responsive to movement of said member by one of said electroniagnets for preventing return of said member to normal position, and means for automatically releasing said member after the other electromagnet has been energized.

9. In combination, a motor, means including an adjustable element for varying the speed of said motor, a movable member, means for moving said member in one direction, means for moving said member in another direction, means controlled by said member for adjusting said element, means responsive to movement of said member in one direction for preventing return of said member to normal position, and means for releasing said member after the means for moving said member in said other direction has been brought into operation.

10. In a synchronizing device, two movable members, means for varying the speed of one of said members, a separate means for each of said members whereby each of said members may operate said first named means, means for energizing both of said last named means simultaneously in opposite directions to prevent actuation of said first named means when said members are in synchronism, and means whereby one of said second named means actuates said speed varying means whenever said members are out of synchronism.

11. In a synchronizing device, two movable members, means for varying the speed of one of said members, a separate means for each of said members whereby each of said members may operate said first named means, means for energizing both of said last named means simultaneously in opposite directions to prevent actuation of said first named means when said members are in synchronism, and means whereby one of said second named means actuates said speed varying means whenever said members are out of synchronism, until synchronism is reestablished.

12. In a synchronizing device, two movable members, means for varying the speed of one of said members, a separate means for each of said members whereby each of said members may operate said first named means, means for energizing both of said last named means simultaneously in op osite directions to prevent actuation of sai first named means when said members are in synchronism, means whereby one of said second named means actuates said speed varying means whenever said members are out of synchronism and means for maintaining one of said second named means operative and the other of said means inoperative until synchronism is reestablished.

13. In a synchronizing device, two movable members, means for varying the speed of one of said members, a separate means for each of said members whereby each of said members may operate said first named means, means for energizing both of said last named means simultaneously in opposite directions to prevent actuation of said first named means when said members are in synchronism, means whereby one of said second named means actuates said speed varying means whenever said members are out of synchronism, means for maintaining one of said second named means operative and the other of said means inoperative until synchronism is reestablished, and means whereby said other member renders said operative means inoperative whenever synchronism is reestablished.

'In testimony whereof I have aiiixed my signature.

ELMER A. SPERRY.

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