US 3882293 A
A rotary type electric switch adapted selectively to bridge a common contact and one of a plurality of contacts for closing a selected circuit, the unique feature thereof residing in the provision of a momentary or "power pulse" actuation mode incorporated as an integral part of such rotary switch.
Claims available in
Description (OCR text may contain errors)
I United States Patent [1 1 [111 3,882,293
Naples et a1. May 6, 1975  QUICK BREAK TYPE SWITCH WITH SNAP 2,675,436 4/1954 Frerer 200/11 G ACTION DEACTUATION STRUCTURE 2,707,741 5/1955 C011ura.... 200/65 X 2,708,227 5/1955 Collura 200/65 X 1 o s: ichard J. Nap New Britain; 2,987,636 6/1961 Jepson 200/157 x Norman H. Newhall, Suffield, both 3,140,364 7/1964 Swanke et al... 200/11 K of Conn. 3,676,617 7/1972 Miller 200/11 G X  Assignee: General Signal Corporation, New
Y k, N.Y.
or Primary Examiner lames R. Scott  Filed: Nov. 23, 1973 Attorney, Agent, or FirmJohn F. Ohlandt  App1.No.: 418,272
 U.S. Cl. 200/154; 200/65; 200/70; T
ZOO/260  ABS RACT  Int. Cl. H01h 5/16 53 i l of seal-chm, 200 11 R, 11 C, 11 G, 11 E A rotary type electric switch adapted selectively to 200/11 EA, 11 K, 63 R, 63 A, 65, 154, 155 bridge a common contact and one of a plurality of R, 157, 291, 335, 336, 339, 11, 63, 70, contacts for closing a selected circuit, the unique fea- 252-26l, 264, 275, 282, 318 ture thereof residing in the provision of a momentary or power pulse" actuation mode incorporated as an 56 References Cited integral part of such rotary switch.
UNITED STATES PATENTS 2,023,219 12/1935 De Reamer ZOO/65 X 6 Claims, 5 Drawing Figures QUICK BREAK TYPE SWITCH WITH SNAP ACTION DEACTUATION STRUCTURE BACKGROUND, OBJECTS AND SUMMARY OF THE INVENTION:
This invention relates to an electric switch assembly and more particularly to an improvement in a rotary type switch by which a momentary or power pulse mode is achieved through the medium of a unitary assembly.
Switches of the rotary type are adaptable for a variety of purposes and are particularly useful in connection with multispeed electric motors for household appliances, such as food mixers and the like. In such an environment only a minimum of space is permitted for housing the switch and it is required that the switch be able to make and break contacts of an electric circuit while avoiding arcing between the contacts.
Examples of the type of switch with which the present invention is concerned may be appreciated by reference to the following US. Pat. Nos. 2,707,741; 2,708,227 and 2,987,636.
For many applications, especially those involving electric food mixers, it is frequently desirable to be able to produce an abrupt increase of power, that is, to propell the beater elements of the mixer at a predetermined selected speed for a limited time period and then to release, or desist from, the predetermined speed of operation almost instantaneously. Such mode of operating the mixer is particularly useful, for example, when a small amount of an ingredient is to be mixed into an already formed mass and rapid incorporation of such ingredient is called for in order to achieve the best possible result, but rapid termination of the step is likewise required. In other words, it becomes necessary to shut off power completely upon finishing the required step and to do so without having to think about further switch actuators. As a result, it is highly desirable to produce the power pulse in such a way that release of the users finger will instantaneously stop the burst of power.
Accordingly, it is a principal object of the present invention to provide an electric switch assembly which by its unitary construction provides the desired stable state switch positioning, but also permits momentary application of desired power to effect a given speed for the motor of the device and quick release or shut off of such power.
Another object is to produce a unitary switch assembly which is relatively simple and inexpensive to manufacture and assemble.
The above and other objects are fulfilled in accordance with a feature of the present invention, according to which further unique selectability. is provided for a rotary type electric switch. One example of such a switch that has been known comprises a movable contact arm, preferably arranged to quickly and abruptly shift in a positive stepping action from one contact position to another in either direction as a control knob is operated. The unique provision of selectability results from the arrangement of an additional contact position to accomplish the momentary or power pulse operation. The added position is judiciously located on the same arcuate or circumferential line defined by the other contact positions. Accordingly, the same basic elements, that is, the aforesaid knob and movable switch am, and, in addition, a control spring, which preferably also functions to permit stable state positioning of contacts to bring about selected speeds of operation, can be utilized for achieving the desired power pulse mode of operation.
Other and further objects, advantages and features of the invention will be apparent from the accompanying drawing in which a preferred embodiment of the invention is depicted.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a front elevational view of an electric switch assembly in accordance with a preferred embodiment of the present invention.
FIG. 2 is a sectional view taken on the line 2--2 of FIG. 1.
FIG. 3 is another sectional view taken on the line 3-3 of FIG. 1.
FIG. 4 is another front elevational view as in FIG. 1,
but illustrating the switch parts in the power pulse operating mode.
FIG. 5 is a schematic diagram illustrating the connections for the switch of the present invention to several windings of an appliance motor.
DESCRIPTION OF PREFERRED EMBODIMENT Referring more particularly to the drawing in which like numerals refer to like parts, the electric switch assembly, generally designated 10, is adapted for mounting in a recess, for example, within a handle of an electric mixer. To this end, the upper wall 12 of such a handle is provided with an opening through which a peripheral portion of a control knob 14 projects. Switch control knob 14 is rotatably supported on a stub shaft 16 which has an enlarged retaining end 18 and a reduced opposing end 20 and which projects through a switch base plate 22, the shaft 16 being suitably se cured to the plate by roll-over of the end 20.
A central or common terminal 24 is anchored to the base plate 22 by the rolled or turned end of shaft 16. At the lower end of the base plate 22, as will be seen, are a plurality of fixed contacts 26, 28, 30 and 32, each of which is formed by a pin 34 to which is secured, at the other side of the base plate, a connecting lug 36 for connection to individual conductors 38, 40, 42 and 44 respectively.
It will be apparent as the description proceeds that the contacts 26, 28, 30 are, in this particular embodiment, snap-action contacts and that the positions for the switch may be considered as stable state positions, i.e. positions which are assumed by the switch upon application of suitable finger pressure and in which the switch remains after such pressure has been removed. Accordingly, one of three possible speeds is stable state selected by connection of the common terminal to one of the contacts 26, 28 or 30. As shown, the speed selected would be in direct relationship to the order of reference numberals applied to the contacts. Thus, contact 26 would select the lowest speed available for the snap-action positions.
For bridging the common terminal 24 with any one of the fixed contacts there is provided a movable, that is, a rotatable switch member 50 which comprises a contact arm 52 and an integrally formed detent arm 54, including a pair of axially extending cars 55. The contact arm 52 is suitably apertured at one end for securing to the shaft 16, and likewise, the detent arm 54 is suitably apertured for the same purpose. The opposite end of the contact arm 52 terminates in a wiping contact surface 56 which is capable of making selected physical contact with the fixed contacts 26, 28 and 30.
The contact arm 52 is struck downwardly so as to impose pressure of the wiping contact surface 56 on the various contacts 26, 28, 30 and 32. This surface 56 is provided with flared side edges to facilitate movement across the contacts.
The detent arm 54 is provided with a detent 54A which is generally concavo-convex in configuration. Suitable openings or recesses 58, 60, 62 and 64 are arranged in the base plate 22 for receiving the detent 54A and for holding same when the switch has been actuated and has moved by the inherent snap action into a given position. The first three recesses, starting with the positioning of the switch in FIG. 1 and going to the right, are so placed in an arcuate spaced manner as to correspond with the positions of the contacts 26, 28 and 30', that is to say, to be in respective radial alignment therewith so that, when the contact arm 52 is touching any one of the contacts 26, 28, 30, the detent 54A will be disposed in the appropriate recess. It will be noted that the fourth recess, that is recess 64, corresponds with the OFF position for the switch. Accordingly, no conductor or wire is connector to a contact at this position, therefore, the contact arm 52 has its wiping surface 56 resting on the base plate in the OFF position.
It will be appreciated from the drawing that the switch member 50 responds to movement of the control knob 14 through the medium of the spring member 66. As best shown in FIGS. 2 and 3, the looped portion 66A of the spring member is adapted to fit around the shaft 16 and the arms 66B and 66C thereof extend outwardly from the shaft to engage with end surfaces 14A and 143 on the control knob 14. One end of the spring I 66 has a hooked portion 66D; that is, there is a hook at the end of the arm 66B so that while there is engagement of this end with the end surface 14A of the control knob, the very end of this hooked portion 66D extends transversely within an arcuate slot 68 formed in the switch base plate 22. The slot 68 extends a sufficient distance so that the hooked portion 66D of the spring is permitted free movement over the full required distance as the knob 14 is being moved in effecting selective contact between the contact arm 52 and the fixed contacts 26, 28 and 30.
'It will be noted that the control knob 14 includes a pointed peripheral portion 14C, which is engageable by the users finger, and also a series of spokes 14D, 14E, 14F extending radially outwardly from a hub 14G at spaced locations. The spoke 14E includes a circumferentially extending lug 14H which also extends axially to such an extent that it is selectively engageable with the slots 70 and 72 at the upper edge of base plate 22. Thus, this lug 14H serves as a means to limit the rotational movement of the control knob 14, because when the lug moves sufficiently in either the clockwise or counterclockwise direction it will engage one or the other of these slots 70 and 72 and hence prevent further rotational movement of the control knob 14. The spokes 14D and 14F serve to initiate movement of the switch member 50 in either the clockwise or counterclockwise direction respectively.
It will be apparent that as the control knob 14 is rotated, for example, in a clockwise direction, as seen in FIG. 1, the spring arm 66C engageable with the end surface 148 will move therewith while the opposed arm.
66B lags behind this movement and hence applies tension, that is, stored energy in the spring 66. However, when the spoke 14F begins to make contact with the switch member 50, as a consequence of further clockwise movement, the energy stored in the spring 66 is abruptly released, thereby causing the switch member 50 to shift to the next succeeding contact position. This so called snap-action will, of course, also occur upon movement of the knob 14 in a counterclockwise direction.
It will also be apparent to those skilled in the art that the detent arm plays a significant part in the preceding operation; that is to say, the detent arm is so designed that the detent 54A will not be easily moved out of a given recess into which it has been placed by the snapaction of the switch, and that it will also serve to restrain movement of the switch member 50 in going to the next succeeding position.
In considering the operation of the switch of the present invention so as to achieve the so called power pulse mode of operation, it should first be understood that when the switch member 50 has been placed in the off position, by reason of the control knob having been rotated such that the switch member 50 has its wiping surface 56 in contact with the base plate 22, there is no circuit established to the mixer motor. This will be especially appreciated by reference to the schematic diagram of FIG. 5 in which connection of the fixed contacts 26, 28, 30 and 32 to individual windings 76, 78, and 82 of appropriate value will be seen. As previously explained, bridging of contact arm 52 with any one of the contacts 26, 28 and 30 is selectively achieved by snap-action involving spring 66.
However, referring now to FIG. 4, further rotation of knob 14 in the clockwise direction does not result in further snap-action positioning. Instead, by application of sufficient force against the bias of spring 66, which is somewhat greater than required for the snap-action positions, the control knob 14 is so rotated that the switch member 50 has its wiping surface 56 come into engagement with the contact 32. Preferably this contact 32 is formed by another pin 34 connected to conductor 44, which, in turn, is connected to a different winding of the motor for the mixer such that a somewhat higher speed for the motor is preferably achievable by this power pulse mode of operation.
It will be seen in FIG. 4 that when the control knob has been so turned in the aforedescribed manner in the clockwise direction the limit on such movement will have been reached because lug 14H is then up against the bottom of slot 72 in plate 22. Moreover, energy continues to be stored in the spring 66 so long as this position for the switch member 50 is maintained by pressure on the knob, the spring being unable to release such energy inasmuch as it has its hooked portion 66D held within the slot 68. As soon as the finger of the user is released from the knob, the knob will immediately return, because of the energy stored in the spring 66, to the OFF position and the burst of power applied to the motor will cease.
While there has been shown and described what is considered at present to be the preferred embodiment of the present invention, it will be appreciated by those skilled in the art that modifications of such embodi ment may be made. It is therefore desired that the invention not be limited to this embodiment, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.
What is claimed is:
1. An electric switch assembly comprising:
a base plate;
a common electrical terminal on said base plate;
a plurality of spaced, fixed electrical contacts arranged in an arcuate line on said base plate;
a shaft secured to said base plate;
a switch member rotatably supported on said shaft,
said switch member including a contact arm for selectively bridging said common terminal with any one of said fixed contacts;
a control knob disposed on said shaft, said control knob being adapted to be actuated by finger pressure and engageable with said shaft so as to control said switch member for selecting contact positions;
means for retaining the switch member in certain of said contact positions after removal of the finger pressure used in selecting such positions;
spring means formed around said shaft and engageable by said control knob such that the spring means is able to shift the contact arm abruptly from certain ones of said fixed contacts to other ones thereof;
means on said base plate for restraining said spring means only when said switch member is being moved to a predetermined one of said contact positions from an adjacent position by application of sufficient pressure to said control knob, such that said switch member will remain in such predetermined position so as to engage the particular fixed contact thereat only so long as said sufficient pressure is being applied, and will return to said adjacent position upon release of the pressure.
2. A device as defined in claim 1, in which a slot is formed through said base plate and in which said spring means has a hook extending into said slot.
3. A device as defined in claim 1, further comprising a centrally located aperture in said control knob, said shaft secured to said base plate projecting through said aperture;
said switch member further including a detent arm integrally formed with said switch contact arm, said integral formation also including a pair of ears which extend axially;
said contact arm and detent arm being suitably apertured and mounted thereby in spaced relationship on said shaft;
a plurality of recesses for receiving the detent formed on said detent arm, said recesses being spaced from and radially aligned respectively with said fixed contacts on said base plate.
4. A device as defined in claim 3, in which said control knob has a wheel shape, including ends;
said spring means being looped around said shaft and engageable by said ends of the control knob such that the ends of said spring means are engaged by the respective trailing ends of said control knob when the control knob is moved in either the clockwise or counterclockwise direction.
5. A device as defined in claim 3, further comprising a hub and an annular peripheral portion for said control knob, and a plurality of spokes extending from the hub to the peripheral annular portion; two of said spokes being adapted to engage with the aforesaid ears on the switch member so as to actuate said switch member in a clockwise or counter-clockwise direction respectively.
6. A device as defined in claim 5, in which an axially extending lug on another of said spokes is effective to limit movement of said control knob.