US2945169A

US2945169A - Remote shaft positioner

Info

Publication number: US2945169A
Application number: US763319A
Authority: US
Inventors: William F Carr
Original assignee: Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 1958-09-25
Filing date: 1958-09-25
Publication date: 1960-07-12
Anticipated expiration: 1977-07-12

Description

July 12, 1960 w. F. CARR REMOTE SHAFT POSITIONER 2 Sheets-Sheet 1 1 Filed Sept. 25, 1958 INVENTOR. WILLIAM F. CARR ATTORNEY July 12, 1960 w CARR 2,945,169

REMOTE SHAFT POSITIONER Filed Sept. 25, 1958 2 Sheets-Sheet 2 8 I ll KW \\\N I Y A" FIG. 2

INVENTOR. WILLIAM E CARR BY mm ATTORNEY by a q dp t pping motor. typically-for each full revolution of the shaft there exists shaft rt g i. This invention has for its principal object the provision Patented July 12, 1960 Claims. (Cl. 318-467) invention relates to devices for causing a loadcarrying shaft in a remote position to execute a relatively precise predetermined rotation under load. Specifically, the device of this invention is intended to cause the operation of a remotely located, multiple-pole, multiple-contac sw tch.-

In complex electrical and radio apparatus it is often required that a large number of switch contacts be made or broken simultaneously with a minimum of effort and sometimes in a remote location. Quite often the switches are all .of the rotary type and may be gauged on a single operating shaft. However, if this is the case, the physical effort required to turn the shaft is often beyond that which can be'conveniently furnished by a human operator and also may be greater than that which may be furnished Furthermore, since a large number of switch positions spaced at a few de- "grees'apart around the shaftaxis, the rotation of the shaft ,must, be controlled very accurately in order to achieve the desired switching action. If the various switch positions are spacedrather closely around the axis of the shaft, it is posslble that any powerful motor device which might be selected to drive the shaft would, due to its own inertia, tend to carry the shaftbeyond the preselected position at which it might be desired that the motorand f a simple,fpowe r ful and positive-means for remotely positioning accurately a load-carrying shaft. I

Another object of this invention is to providemeans 9?! e e ltin acc ate-rem e posi n n g n u tiple contac't switches." i:

It is another object of this invention to provide an accurate remote indexing device.

Other objects of invention will become apparent from the following description taken, in connection with the accompanying drawings, in which a Fig. l is aplan schematic view of the invention;

Fig. 2 is a sectional view of the invention, taken at 2- in Fig. l;

Fig. 3 is a partial sectional view of the invention taken at 33-3 in Fig. 1; and

Fig. 4 is a partial sectional view of the invention taken at 4-4 in Fig. 1.

Referring now to the drawing, there is shown a motor 1 connected at one terminal to a battery 2, or other source of power. Motor 1 is mechanically connected through a gear train 3 to a gear 4, which drives main gear 5. Main gear 5 is rotatable upon a shaft 6 and has integrally attached to it an eccentric circular cam 7, as shown. Cam 7 carries cam follower 8, having arms 9 and 10 extending therefrom, as shown. Follower 8 is free to rotate upon cam 7, except that Belleville spring 11 shown in Fig. -2 being somewhat compressed, causes the frictional engagement of follower 8 and cam 7.

Arm 9 has integrally attached to it a drive pin 12 adapted to engage the teeth 13 of ratchet wheel 14, which is carried for rotation upon a shaft 15. Shaft 15 is arranged to rotate a plurality of ganged switches 16, or other mechanical load. Shaft 15 also drives a rotatable switch wafer 17 about which are positioned multiple fixed contacts, such as 18, 19, 20, 21, 22, 23, 24 and 25'. Contacts 18 through 25 are in turn connected to

contact points

26, 27, 28, 29, 30, 31, 32 and 33 on remote selector switch 34 having a rotatable contact arm 35.

For purposes to be hereinafter explained, it is preferable that the number of contacts about wafer 17, as well as the number of contacts on selector switch 34 and the number of teeth of ratchet wheel 14, be the same or be multiply related.

Ratchet wheel 14 and shaft 15 are caused to rotate in discrete steps corresponding to a single tooth position of the ratchet gear and a single switch position of selector switch 34 by means of Wafer spring 36 held in fixed position by means of

bolts

37 and 38. Wafer spring 36 incorporates

gear members

39 and 40 having holes 41 and 42 therein. Holes 41 and 42 contain

small steel balls

43 and 44 which rest in detents 45 in detent plate 46 which is attached to shaft 15 and rotates therewith.

Motor 1 is also connected to wafer -17 by any permanent means, such as a slip ring, and battery 2 is arranged by the connections, as shown, to energize solenoid 47 whenever motor 1 is energized. Solenoid 47 is mounted adjacent main gear 5 and cam follower 8, as shown, and

tended as shown in Fig. 3.

so as to interfere with the motion of arm 10 of follower 8 unless current is applied to the solenoid.

In operation the device functions as follows. Selector switch 34, being at a remote position, may be rotated so that rotatable contact 35 touches any one of the fixed contacts. Assuming that the operator, just prior to the time depicted by Fig. 1, has movedthe selector switch so that rotatable contactor 35 touches fixed contact 31, it can beseen that current flows from battery 2 through arm 35 to contact-31, thence to contact 18, wafer 17, and

' counterclockwise.

back to the motor. The motor thereforerotates. At the same time, it can be seen that current flows through the 'windingfof solenoid 47, causing plunger 48 to be withdrawn clear of arm 10. Gear 5 is caused to rotate a counterclockwise direction in Fig. 1 by the action ofmotor =1, gear train 3, and 'gear 4. Cam follower 8 therefore-moves to the right in Fig. 1, as shown, causing pin 12 to'engage' a tooth of ratchet gear 14 which advances the gear one gear tooth and causes ganged switches 16 and wafer 17 to beadvanced by the same increment. The

mot-ion of ratchet wheel 14 and shaft 15 is likewise However, when this step has been completed it can be seen that current still flows to the motor. Accordingly, the ratchet wheel continues to be advanced one tooth position for each rotation of main gear 5. This process continues until notch 58 in wafer 17 comes to rest on the particular contact through which power is supplied to motor 1. In this case that contact is contact 18 and corresponds to the selector switch position chosen for switch 34. At this point, current no longer flows to motor 1 and solenoid 47, so two things happen. First of all, motor -1 coasts to a stop. However, before this can happen, solenoid 47 is de-energized, releasing plunger 48 which immediately interferes with the motion of arm 10 of follower 8. For each revolution of main gear 5, it can be seen from Fig. 1 that arm 10 oscillates from a position which is non-interfering with respect to the postion of plunger 48 to a position which is interfering. Accordingly, although main gear 5 may continue to rotate because of the inertia of motor 1 and gear train 3, after current is interrupted, the very next attempt which cam follower 8 makes to advance ratchet gear 14, the solenoid plunger interferes with the necessary motion and cam 12 fails to engage the ratchet wheel. The positions which pin 12 and arm 10 occupy when plunger 48 is in interfering position are shown. by dotted lines in Fig. 1. When plunger 48 blocks movement of arm 10, the only force withstood by the solenoid plunger is that caused by the friction of Belleville spring 11 against follower 8, as shown in Fig. 2.

While ganged switches commonly employ some type of detent mechanism which assures that the switch stops at discrete positions, assuring optimum electrical contact between the rotatable member and the fixed switch con tacts, it is also possible to incorporate such a detent mechanism with the ratchet wheel assembly as shown in Fig.

4. InFig. 4, detent plate 46 has cut in it a number of holes corresponding to the number of switch positions or discrete shaft positions desired, and

balls

43 and 44 are caused to deflect gears 41 and 42 of leaf spring 36 which is fixedly supported at 37 and 33, as shown. Any comparable detent indexing device well-known in the art may be utilized so long as it assures the motion of ratchet ,wheel 14 in discrete steps. U It should be understood that the eccentricity of cam v7, the length of arm 9, the depth and dimensions of ratchet wheel teeth 13 must be coordinated so that the motion of the cam follower for each revolution of main gear is just that required to advance the ratchet wheel one tooth position. Likewise, it is possible, of course, to .have a number of teeth on ratchet wheel 14 which is any even multiple of the number of switch positions or discrete shaft positions desired. For example, as shown in Fig.

1, the device takes care of eight remote switch positions. To accomplish this result it is contemplated that a minimum of eight teeth are required on ratchet wheel 14.

However, the same result would be accomplished by the switch 34.

By the use of a solenoid 47 it is seen that the possibility of the device overshooting the desired index position, as

.determined by selector switch 34, is positively eliminated since follower 8 becomes inoperative to advance ratchet heel 14 the moment power to motor 1 and solenoid 47 is interrupted by virtue of switch -15 reaching the desired preselected position.

Although the invention has been described and illusselected to provide any desired mechanical advantage, it can be seen that substantial torque can be made avail able on shaft 15 to turn ganged switches 16, or any other device which needs to be indexed, at discrete preselected positions corresponding to the various positions of trated in detail, it is to be clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of this invention being limited only by the terms of the appended claims.

I claim:

1. In combination, an n-position rotary switch, an ntooth ratchet gear connected to drive said switch, a totatable shaft, eccentric means attached to said shaft, follower means frictionally engaging said eccentric means and having an arm periodically engaging said ratchet-gear to rotate it one tooth position for each revolution of said shaft, a second arm on said eccentric means, plunger means normally engaging said second arm to prevent said first arm from engaging said ratchet gear, solenoid means for disengaging said plunger means when energized, a motor driving said shaft, and switch means operable by said ratchet gear for energizing said motor and solenoid until said ratchet gear has been rotated to a predetermined posltion.

2. In combination a motor, a rotatable shaft driven by said motor, an n-tooth ratchet gear connected to a switch shaft, eccentric means attached to said rotatable shaft, follower means frictionally engaging said eccentric means and having an arm periodically engaging said ratchet gear to rotate it one tooth position for each revolution of said shaft, a second arm on said follower means, plunger means normally engaging said second arm to prevent said first arm from engaging said ratchet gear, sole-. noid means for disengaging said plunger means when energized, and switch means connected to said switch shaft for energizing said motor and solenoid until said ratchet gear has been rotated to a predetermined position.

3. The device as claimed in claim 2 in which the switch means includes a multi-position rotary switch having a rotor with an electrical contact point corresponding t all but one of the multiple positions.

4. The device as claimed in claim 3 in which said switch means also includes a remote selective-type switch by said switch shaft.

References Cited in the file of this patent UNITED STATES PATENTS 2,760,139 Luebking Aug. 21; 1956