US2638004A - Combined friction drive and detent - Google Patents

Description

y 2, 1953 R. L. BOYLES 2,638,004

COMBINED FRICTION DRIVE AND DETENT Filed Feb. 15, 1952 Fig.-

Inventor-z Robert L. Bqgles H is Attorney.

Patented May 12, 1953 COMBINED FRICTION DRIVE AND DETENT Robert L. Boyles, Framingham, Mass., assignor to General Electric Company, a corporation of New York Application February 15, 1952, Serial No. 271,833

My invention relates to a combined clutch, friction drive and detent mechanism. It will be explained for the purpose of operating a switch and as thus used may be considered to represent an improvement on the so-called sleep switch described in United States Patent No. 2,505,573, to Prophet, April 25, 1950, assigned to the same assignee as the present invention. The patent mentioned describes time switch mechanism for controlling a radio and the like, and includes a switch associated with a timing device by means of which a person may turn the radio on for a predetermined adjustable period, the switch to be opened and the radio to be turned off automatically at the end of such period. According to my invention, I provide a friction drive switch control means which also serves as a clutch and a detent by means of which the person turning the switch on may set the on timing period approximately by feel in the dark or without looking at the control means.

The features of my invention which are believed to be novel and patentable will be pointed out in the claims appended hereto. For a better understanding of my invention reference is made in the following description to the accompanying drawing in which Fig. 1 represents a face view partially in section of my invention as applied to a time switch. Fig. 2 shows a side view of the friction drive of my invention. Fig. 3 is a face view of the friction drive member showing the detents therein, and Fig. 4 is a perspective exploded view of the application of my invention to a time switch mechanism of the character represented in Fig. 1.

In Fig. 1 there is represented a portion of a clock face 5 with the usual time telling hands. To the rear of the dial there is a switch having upper and lower resiliently supported contacts 6 and 1 leading to terminals at 8 (see also Fig. 4), and by means of which a circuit such as a radio circuit in which the switch is connected may be opened and closed. The lower switch contact may be pressed downward and allowed to rise again to open and close the switch by the finger 9 of an actuator made of insulating material and rotatable about or with the rod l0. actuator is operated automatically to close the switch under certain conditions at a predetermined time by mechanism, not shown, but which may be similar to that shown in the previously mentioned Patent No. 2,505,573. The actuator also has a, finger 9a engageable by a part II of a rotatable manual control to open the switch when such manual control is in the rotary position represented in Fig. 1. The manual control This- 4 Claims. (Cl. 74-207) part may be rotated further clockwise to cause a cam portion |2 thereof to engage an arm l3 fastened to the upper contact 6 and press such contact downward to close the switch. The manual control has a third position, counterclockwise from the position shown in Fig. 1, where neither parts H nor i2 interfere with the operation of the switch such that it may be open or closed, depending upon the position of the actuator finger 9 and the manual control of my invention. A spring |4 engages a detent member I5 on the shaft of actuator II to determine the three positions of such shaft.

Ordinarily, when a person retires at night, the switch is held open by finger 9 pressing down on contact 1. Under these circumstances it often happens that the user will wish to have the switch closed and the radio operating while he or she is dropping off to sleep and have the switch open automatically and the radio cut off in a relatively short time, such as 15, 30, or minutes, and to accomplish this without disturbing the setting of other controls of the switch, such as the parts 9, 9a and I2. It is the primary purpose of the control of my invention to enable the apparatus to be used for this latter purpose as also is the purpose of the so-called sleep switch feature of the above-mentioned patent. My invention represents an improvement in this feature in that it uses fewer parts and has the advantage that it can be set in the dark, or without looking at it, to approximately the desired radio operating time.

The sleep switch feature includes the lever I6 pivoted on rod Ill and having one end I! positioned to engage an insulating arm l8 secured to top resilient switch contact member 6, and its other end l9 in engaging relation with a cam 20 which constitutes a part of the friction detent drive.

The cam 20 is securely fastened to a shaft 2| which is provided at the front of the clock with a button 22 by means of which the shaft 2| and cam 20 may be manually turned. The button 22 on shaft 2| is preferably provided with an index 23 indicating on a scale 24 to show the adjusted position of shaft 2| and cam 20. The cam has an upper sector portion 25 having a peripheral surface generally circular with respect to the shaft 2| as a center, which surface is in frictional driving relation with a grooved friction wheel 26 integral with a pinion gear'2'l on a shaft 28. It is immaterial whether the parts 26 and 21 rotate on shaft 28 or are fastened -to the shaft and the shaft is made rotatable;

Gear '21 is in mesh with a gear 29 which is continuously driven by the clock in a counterclockwise direction and at a speed suitable for the purpose intended. I provide means for resiliently maintaining the engaging surfaces of sector and wheel 26 in firm engagement. For instance, one of the shafts 28 or 2! may be resiliently biased toward the other, or the sector :25 may be made of relatively thin resilient Ina-- terial and have an offset as shown, so as to have sufiicient radial resiliency to maintain firm contact with wheel 26 at all engaging positions, or I may use a combination of such means. In the illustration the front end of shaft 21 915 pivoted in an opening in a "front plate, the

opening 3i] being elongated in a direction radial with wheel 26, and the shaft 21 at this point is urged toward wheel 25 by a spring 3i having its opposite ends hooked into openings 32 in the front plate and having its middle portion bent and under straightening tension beneath shaft 21 adjacent the slot 3.8. .Thus the drive surface of part 25 is urged against and in driving relation with the drive surface of wheel 23, by spring .31, while allowing limited up-and-down movement of the forward end of shaft (2-! and cam .member -2fi25.

When the button 22 and parts attached there to are turned counterclockwise from the on. position shown to an inactive or off position limited :as by astop indicated at (it and with the indicator .23 to the left of the .scale 124, the end IQ of lever is no longer rides on the raised portion at of cam 22 and, hence, lever arm 16 has a position clockwise from that shown, and. its end 1|? does notpress down on l8 and it does not hold :contact 6 down against contact .i such that the switch will be open so far .as the sleep switch feature is concerned. It .is assumed that the other controls of the switch are such that the switch is open. Also the .sector 25 will have moved sufiiciently counterclockwise from the. position shown to disengage the driving con-I nection between 25 and 26. Now, to close the switch for ,a predetermined time interval .so' that .it will open automatically, shaft .2] is turned clockwise by button 22 so that cam surface 35. rotates lever 16 counterclockwise, contact arm 6 is bent downward against its own resiliency to close the switch, .and the drive surface of sec: tor .25 engages wheel .25. During this manual closing ofthe switch, the sector 25 after engage: ment with wheel 2t slips on wheel 28 because wheel .26 is constrained by its geared connection with the clock train to rotate slowly at a speed determined by the gear ratio. However, as soon asbutton 22 is released, and isno 'longermanuallyrestrained, the connection between 2% and 25 becomes a driving connection and wheel 26 s'low-' ly-drives sec'tor 2-5 and the other parts connected to shaft 2| in a counterclockwise direction at a constant rate until the parts are driven to the idle or off position and the switch opens.

For "the purpose described, the rate of rotation of shaft 2"! by the clock is made such that the scale graduations at 24 represent 15 minutes each, and the device :is arranged to provide for a timing operation up to one .hour. Figs. .1 and 4, the position of indicator .23 indicates that in one-half hour the :clock will move the sleep switch control features to an idle .posi-. than and permit the switch to .open so far .as this-control,isconcerned. When the sleepxswitch timing feature .is in operation, the switch clos-. ing time maybe extended or reduced by .a .corresponding manual adjustment by button 22.

Thus, 'in,

The connection between 25 and 26 slips or acts as a positive friction drive, depending upon whether shaft 2| is manually restrained or moved as in a setting operation, or is left free to rotate.

It will be noted that the driving surface of sector 25 is not perfectly circular but has a number "of shallow scallops or detents therein. These detents are sufiiciently shallow that they do not interfere with either the friction clutch slipping action during manual adjustment or the positive friction drive during a timing operation, since it will be evident that the spring 3! retains sector 25 .pressed against wheel 26 at :all times, except when the parts are in the idle condition. The detents are, however, sufiicient- -=ly definite and spaced that as the shaft 2! is manually turned by button 22, there is a distin'ct variation in the turning force required such that the turning operation may be stopped at anyone "of the detent points by .feel. Thus, as a detent point on sector 25 approaches contact with wheel 25, the manual turning force ;re quired is less than that required to move :sector 25 away from such detent contact point so that in making a manual adjustment, the sector 25 tends tostop at the positions where the detentstfi, 3.1:and 38 engage the wheel 26 :such that a per son can easily adjust the time setting to any one of such detent contact points by feel. :In the example given, these contact detent points have been positioned at the :15, 3,0, and 45 minute time adjustment positions. The full hour .ad justment may be made by feel by providing :an upper limit stop indicated at 39 for such adjustment point. Thus, a person ,in the dark or without looking at the scale 24, can adjust the time for automatic switch operation to approxh mately the desired value by feel. The '15, 3,0, 45 and .60 minute adjustments can be made exact ly, and a reasonably close approximation :adjustment can be made for intermediate time intervals. The ability to make these adjustments by reel is particularly desirable for the sleep switch application described, and also for blind persons.

. :It will he noticed that in forming thedetent surface of 25, the slopes into a detent Point such as the "point 3.8 have been made steeper and shorter at the left .side than on the right sid of the detent points. Thus the steeper and shorter slopes face toward the trailing or leftside of the driving wheel 25, .so that in .:-a normal setting operation by rotation of the sector 25 clockwise manually, the more abrupt :or steeper slope is encountered in moving a .detent .poiht past the contact point-of driving wheel 126. Eur. ing this setting operation no friction driving action is required, and ample manual force is available to-slip the engaging surfaces. 0n the other hand, when the sector 25 is being rotated counterclockwise by the clock in a friction driving, timing operation, only the more gradual slope is encountered in driving a detent point past wheel 26 and no slippage occurs. While the amount and differences in slope represented are not very critical, a diirerence such as indicated is "to be preferred because by so doing the detent feel in setting is emphasized while obtaining a "high factor of safety against slipping and theleast variation in load on the clock driving motor during a sleep switch timing action.

It will now be apparent that I have provided a simple, low-cost, reliable ,and sturdy control device .in which the part 2.5--35 canbea stamping, and that it serves with wheel 26 as a friction clutch, a friction drive, and as a setting adjustment detent.

In accordance with the provisions of the patent statutes I have described, the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A combined clutch and friction drive comprising a wheel adapted to be continuously driven in a given direction, a manually adjustable rotary shaft having an axis of rotation substantially parallel to the axis of rotation of said wheel, a sector-shaped member fixed on said shaft and having a generally circular periphery rotatable into and out of frictional driving engagement with the periphery of said wheel, the peripheral engaging surface of said sectorshaped member having spaced shallow depressions forming setting gauging detents along its engaging surface, resilient means for maintaining the engaging surfaces in contact in all rotary engaging positions, and means for manually rotating said shaft to establish and adjustably set said frictional driving engagement relation, the engaging surfaces slipping during such setting and when not manually restrained said shaft is driven by said wheel through the adjusted engagement range of operation of said parts without slippage.

2. A combined clutch and friction drive comprising a wheel adapted to be driven in a given direction at constant speed, a shaft to be driven thereby, a sector-shaped clutch member secured on said shaft having a generally circular peripheral surface rotatable into and out of frictional driving engagement with said wheel, the engaging surface of the sector-shaped clutch member having uniformly spaced shallow detent depressions along its periphery, means resiliently maintaining the surfaces of said wheel and clutch member in firm contact with each other when engaged, and means for manually rotating said shaft for the purpose of rotating the sector-shaped clutch member thereon into driving engagement with said wheel and setting the clutch member to any desired rotary engaging position with said wheel, the engaging surfaces slipping during such adjustment, said wheel then driving said clutch member to disengaging position without slippage when said shaft is not manually restrained.

3. A friction drive and clutch mechanism comprising a rotatively mounted driving wheel and a rotatively mounted sector-shaped clutch member having a generally circular peripheral surface rotatable into and out of driving engagement with the periphery of said wheel, said clutch sector having shallow detent depressions spaced along its engaging surface, means for resiliently maintaining the engaging surfaces in firm contact when in driving relation, means for continuously rotating said driving wheel in a given direction at a predetermined speed, and means for manually rotating said clutch member from disengaging to engaging position with respect to wheel and to set their relatively rotary engaging positions, their engaging surfaces slipping during such manual setting operation, said wheel then driving said clutch member to disengaging position without slippage when the clutch member is not manually restrained, the side slopes into the shallow peripheral detent depressions of said clutch member which face toward the trailing side of the driving wheel being shorter and steeper than the other side slopes into such depressions.

4. A combined friction drive and setting clutch for a time and manually controlled on, off operating device comprising a wheel driven at a constant speed in a given direction, a rotary control shaft, a sector mounted on said shaft positioned such that its periphery may be rotated into and out of driving engaging relation with the periphery of said wheel, manual means for rotating said shaft from an ofi control position where its sector is disengaged from said wheel to an on control position where its sector is engaged in driving relation with said wheel and adjusting said sector to any desired on engaging position with said wheel, such manual adjustment being accompanied by slippage between the contacting surfaces of wheel and sector, shallow cletents uniformly spaced along the peripheral engaging surface of said sector for the purpose of enabling the on time setting position of said sector to be determined by feel during the manual setting operation, and resilient means for maintaining the contacting surfaces of wheel and sector in driving relation in all engaging positions, said shaft and sector being driven to an oif position in a time period determined by the on setting adjustment and beginning as soon as said shaft is manually released after an on setting operation.

ROBERT L. BOYLES.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,367,016 Gallagher Jan. 9, 1945 2,455,326 Bowditch Nov. 30, 1948 2,540,738 Kaplowitz Feb. 6, 1951

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