US2438617A - Wafer switch - Google Patents

Description

March 30, 1948. D. P. MOSSMAN, SR

WAFER SWITCH Filed Jan. 14, 1946 2 Sheets-Sheet 1 March 30, 1948. 'D. P. MOSSMAN, SR

WAFER SWITCH Filed Jan. 14, 1946 2 Sheets-Sheet 2 QYNN $9 I fnvevlzr r janai fimasmarb 57:

Patented Mar. 30, 1948 UNITED STATES PATENT OFFICE WAFER SWITCH Donald P. Mossman, Sn, Chicago, Ill.

Application January 14, 1946, Serial No. 641,048

7 Claims. (01. 200-4) The present invention relates to wafer switches such as that shown in my prior application, Serial No. 617,791, filed September 21, 1945, for Wafer type switches. In switches of this character there are usually a plurality of supporting wafers or discs which carry stationary contact elements to which wiring terminals are attached. A series of movable contact elements are usually carried upon other discs which are mounted upon a shaft that extends through a series of the stationary contact carrying wafers. It is the purpose of the present invention to provide a new contact actuating mechanism for the individual movable contacts whereby to obtain a construction that keeps the spring out of the current carrying part of the switch, and furthermore provides a fast and clean break of the circuit by imparting a second motion to the movable contact element as it leaves circuit closing position.

It is a further purpose of my invention to provide a novel movable contact or bridging element construction in a wafer switch of such nature that it can readily be adapted to circuit control conditions where it is necessary to avoid opening the circuit as the contact steps from one of the stationary contacts to another.

The nature and advantages or my invention will appear more fully from the following description and the accompanying drawings wherein a preferred form of the invention is shown. It should be understood, however, that the description and drawings are illustrative only, and are not to be considered as limiting the invention except insofar as it is limited by the claims.

In the drawings:

Figure 1 is a longitudinal sectional view through the wafer switch embodying my invention;

Figure 2 is a sectional view taken substantially on the line 2-2 of Figure 1 Figure 3 is a fragmentary sectional view taken on the line 3-3 of Figure 1;

Figure 4 is an enlarged sectional view through the movable contact or bridging bar taken on line 4-4 of Figure 2, illustrating the detailed construction thereof;

Figure 5 is a sectional view through the bridging contact structure taken on the line 55 of Figure 4;

Figure 6 is a sectional view on a reduced scale showing a modified contact arrangement, and

Figure 7 is a fragmentary sectional view on the line 1-1 of Figure 6. 7

Referring now to the drawings, the wafer switch shown herein is made up of a metal base plate II) to which mounting posts II are secured. These posts serve to mount spaced discs I2 and I3 upon which annular series of stationary contacts I4 and I5 respectively are mounted. The manner of mounting is by providing apertures in the insulating discs I2 and I3 as shown at I6 and II. In the disc I2 the stationary contacts have central plugs extending into the openings I6. In the disc I3 the mounting is slightly different because the stationary contacts I5 are wider. In this case the stationary contacts have side prongs that extend through the openings I1, and are clinched over. Each of the discs I2 and I3 also carries an annular contact ring l8. The ring I8 on the disc I3 is a flat ring and has several prongs I9 extending through apertures in the disc I3. For purposes of making electrical connections to the inner contact member I8, this member is provided with an elongated strip 20 that passes through the disc I3 and is bent outwardly for connection to a conductor.

The inner contact member I8 on the disc I2 is fastened in the same manner as the contact member I8 on the disc I3. However this member is of a different construction. It is composed of a top ring of material which is flat and which has the prongs 2| that extend through the disc I2 and are clinched over. In addition there is a cam member 22 provided beneath the top memher. This cam member has its periphery flanged up to provide a plurality of cams 23 between the several stationary contacts I4.

Plate Ill and the discs I2 and I3 have bearings 24, 25 and 26 respectively mounting a shaft 21 which has a finger piece not shown thereon for rotating the shaft, and which has movable contact carrying discs 29 and 30 fastened thereon. The rotation of the shaft is under the control of a detent mechanism which comprises a star wheel 3| fixed on the shaft, a lever 32 pivoted on the plate III by a pivot 33 and having a roller 34 engaging the teeth of the star wheel. The free end of this lever is held under tension to press the roller against the star wheel by a spring 35 which is secured to a post 36 on the plate III. In order to limit the rotation of the star wheel the plate I0 has a series of apertures 31 therein and a washer 38 which is clamped in place by the shaft bearing 24 of the plate I0, and which is provided with prongs 39 extending through the openings of the plate Ill into the path of a projection 40 that is integral with the star wheel.

In order to establish contact between the outer space between bridging members.

contact members such as M and I5, and the inner contact rings, suitable bridging members or movable contacts 4| are provided on the discs that are carried by the shaft. These bridging members are essentially the same and may be provided in any desired number depending upon the nature of thecircuit control desired, and the number of outer stationary contacts. In order that this variation may be possible, the movable discs of insulating material are provided with an annuular series of apertures 42, the spacing of which is equal to twice the spacing between the outer stationary contacts, since at all events it will be necessary to have at least that much The bridging members 4! constitute fiat metal bars which have adjacent each end a pin 43 one of which forms a contact to engage the inner contact ring. The other pin 4-4 at the outer end of the bridging member 4! is adapted to engage the stationary contacts such as M and i5. Between its ends the bridging member is engaged by a coiled spring 45 that is mounted in an eyelet 46. secured in one of the apertures 42 of the insulating disc. A pin 5i at the center of the bridging member extends into the spring 45 and the eyelet 45. The brideing contact member is supported and guided by a yoke t? having two wing portions 48 and 59 that are fastened to the disc and having an elongated aperture 58 to receive the pins 43 and 44. Thus the bridging members M are held in a floating fashion under the pressure of the spring 45, but the spring itself is not a current carrying member. In the bridging members iii that engage the stationary contacts I4, I provide central heads 52 which project down into the path of the cam member 22. This is done in order that as the bridging member passes away from a stationary contact by rotation of the disc carrying it, the bridging member will receive a lift from the cam so as to quickly clear thestati-onary contact member by a break in a direction substantially perpendicular to the contact .face of the stationary contact as well as by the movement in a direction parallel to the contact face, caused by the rotation of the disc. This is not a snap action. It is a quick contact breaking action that avoids the weakness of the usual wiping break, wherein excessive arcing usually occurs as the movable member leaves the stationary member. After a minute lateral motion the movable member is lifted on of the face of the stationary member before the lateral motion carries the movable member past the-edge of the stationary member. Since the lateral motion continues, the break is not vertical from the stationary member but is inclined somewhat and is-at a speed which is the resultant of the lateral. and lifting movements.

In certain cases it is essential that the circuit be not broken when the movable contact is shifted from one stationary contact to another. In order to accomplish this result the only change necessary is to leave off the cam member 22 and to provide an enlarged head on one of the contact pins 44 of the bridging member. Such a construction is shown in the bridging member used with the contacts most remote from the plate It where the head id is provided, on one pin 44. This head is of sufficient size to bridge from one of the stationary contacts to the next one. I

Figures 6 and '7 illustratea somewhat modified bridging contact structure to fit those situations wherein it is desired to progressively bridge pairs of stationary contacts where all the stationary contacts are in a single circle, This contact an rangement is also intended as an alternate to either of the movable contacts on 41. In the case of a circuit breaking switch it would be provided with a pin 44. In the case of a make before break switch, it would be provided with a pin having an enlarged contact 43. In both these cases it would be mounted radially rather than circumferentially. The bridging member 55 of Figures 6 and 7 comprises a bar of conducting metal having contacts 56 and 5'! thereon positioned the same distance apart as the several contacts 58 mounted on the stationary disc 59 of insulation. The bar 55 has guide pins 60 and 6| at its opposite ends. These pins are preferably formed by bending up narrow extensions at the ends of the bar so they extend at right anglesto the bar. The rotary disc 62 of insulation has apertures 63 and 54 in which the pins 55 and BI are guided.

The bar 55 is so mounted on the disc 62 as to have a limited movement toward and away from the disc by an eyelet 55 that is secured in the disc 62, by a flange 55 on one end of the eyelet, and a bell portion 6'6 at the other end. The bell portion is turned in .to form a seat at 58 for a coiled spring 59 which is under compression. The bar 55 has a pin TE! fixed thereto, The pin NJ extends through the spring 59 and through the seat 88., A stop H is secured on the pin to engage the end cf the eyelet 65 and limit the movement of the bar 55 by the spring 69. The pin 10 has a cam engaging head i2 thereon which is adapted to engage the cams 23 when this bridging member is used with a cam member 22 in place of the bridging member 45.

It is believed that the nature and advantages of my invention will be clear from the foregoing description. The parts of the device are of such nature that they are readily stamped out and formed in an economical way. The several discs for the stationary contacts are alike in construction. This is true, also, of the insulating discs which carry the bridging members. The construction and mounting of the bridging members is such that they may be easily assembled with the insulating discs at the desired positions.

Having thus described my invention, I claim:

1. In a wafer switch of the character described, a bridging contact and mounting therefor comprising a supporting disc of insulation having an aperture, an eyelet seated in the aperture and provided with a spring seat at one end, a coil spring in said eyelet, a bridging bar having contact portions at its ends and having a central pin projecting into the spring and aperture, and means limiting the movement of the bridging bar away from the disc.

2. In a wafer switch of the character described, a bridgin contact and mounting therefor comprising a supporting disc of insulation having an aperture, an eyelet seated in the aperture and provided with a spring seat at one end, a coiled spring in said eyelet, a bridging bar having contact portions at its ends and having a central pin projecting into the spring and aperture, and means limiting the movement of the bridging bar away from the disc, said means comprising a yoke secured to the supporting disc.

3. In a wafer switch of the character described, a bridging contact and mounting therefor comprising a supporting disc of insulation having an aperture, an eyelet seated in the aperture and provided with a spring seat at one end, a coiled spring in said eyelet, a bridging bar having contact portions at its ends and having a central pin projecting into the spring and aperture, and means limiting the movement of the bridging bar away from the disc, said means comprising a portion of said central pin projecting through the eyelet and a stop on said portion for enga ing the eyelet.

4. In a wafer switch of the character described, a bridging contact and mounting therefor comprising a supporting disc of insulation having an aperture, an eyelet seated in the aperture and having a bell portion on one side of the disc with the free edge turned in to provide a spring seat, a coiled spring in the eyelet engaging said seat, a bridging bar having contact portions at its ends and having a central pin projecting through the spring and eyelet, and a stop on the free end of the pin for engaging the turned in end of the eyelet and limiting the movement of the bar outward from the disc.

5. In a wafer switch of the character described, a bridging contact and mounting therefor comprising a supporting disc of insulation having an aperture, an eyelet seated in the aperture and having a bell portion on one side of the disc with the free edge turned in to provide a spring seat, a coiled spring in the eyelet engaging said seat, a bridging bar having contact portions at its ends and having a central pin projecting through the spring and eyelet, and a stop on the free end of the pin for engaging the turned in end of the eyelet and limiting the movement of the bar outward from the disc, the disc having guide apertures on the opposite sides of the eyelet, and guide pins on the bar extending into said apertures.

6. In a wafer switch of the character described, a bridging contact and mounting therefor comprising a supporting disc of insulation having an aperture, an eyelet seated in the aperture and provided with a spring seat at one end, a coiled spring in said eyelet, a bridging bar having contact portions at its ends and having a central pin projecting into the spring and aperture, the disc 5 having guide apertures therein adjacent to the ends of the bar, and guide pins on the bar eX- tending into said apertures.

'7. In a wafer switch of the character described, the combination with spaced apart discs of insulation, means mounting said discs and including means to rotate one disc with respect to an adj aeent one, of contact members fixed 0n certain discs in annular rows and bridging contacts carried by discs adjacent thereto, said bridging contacts comprising bars having contacts at the ends thereof, guide pins on said bars extending into apertures in the discs supporting the bars, springs seated in said discs and urging the bars outward to engage the contact members, cam means on the discs carrying said contact members and engaging said bars to lift the contacts thereof away from the contact members as ad- -jacent discs are rotated with respect to each other, and cooperating means on the discs and bars limiting the outward movement of said bars, said cam means comprising a washer having a corrugated periphery flanged upward to extend transversely to the plane of the washer.

DONALD P. MOSSMAN, SR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Brackett Jan. 12, 1915 Soreng May 28, 1929 Hill Dec. 1, 1942 Number

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