US1907141A - Electric switch - Google Patents

Description

May 2, 1933. A- 1 owug 1,907,141

ELECTRIC swrrcn Filed Aug. 24, 1928 Patented May 2, 1933 UNITED STATES FFICE PATENT AUGUSTUS J. BOW'IE, OF SAN FRANGISGO, CALIFORNIA ELECTRIC SWITCH Application filed August 24, 1928. Serial No. 301,839.

53 ranged to insure correct contact between the blades and clips of the difierent phases when the switch is closed; to operate without objectionable and damaging slamming and hammer blows in closing, and provide ample power to operate the movable switch parts after the contacts have corroded and tend to stick from long periods of disuse,without too great a manual effort on the part of the operator.

An object of this invention is to provide an improved switch of the character described which will be comparatively simple and inexpensive as to construction in consideration of the many advantages gained, and which will 1 be easy to operate, strong, durable and capable of use over long periods of time without requiring servicing or repair.

A further object is to provide a switch of the character described in which the advantages gamed are primarily due to an O: movedv thereby. By this arrangement torsional distortion of the rock shaft was frequently brought about with the result that improper seating of the switch contacts would occur, or slamming andhammer blows of said contacts were caused. With the operating means of my invention these objections and difliculties are eliminated by mount ing the rock shaft and movable switch 1 enrbers separately and connecting the shaft with said members by toggle mechanisms. which mechanisms come on dead center when the switch is closed and thereby nullify the tendency of hammer blows and improper seating of the contacts, as would otherwise caused when the rock shaft is distorted torsionally or wound up. This distortion cause is primarily removeddue to the separate mountings of the movable switch members and rock shaft.

With the above mentioned and other objects in view, the invention consists in the novel construction and combination of parts hereinafter described, illustrated in the accompanying drawing, and set forth in the claims hereto appended, it being understood that various changes in the form, proportion, size and minor details of construction within the scope of the claims may be resorted to without departing frow the spirit or sacrificing any of the advantages of the invention.

Referring to the drawing in which one form of my invention is shown:

Fig. 1 is a side elevation of a multiple switch made in accordance with my invention, and

Fig. 2 is a top plan view of the switch.

One embodiment of my invention as illustrated in the accompanyingdrawing comprises a three pole gank operated switch i which each switch phase is mounted on a base member 1, adapted for anchorage on a suitable support, not shown.

Each switch phase comprises amovable switch member 2 pivoted at 3 on its base 1 and supper ing an insulator 4L carrying the usual switch blade 5. The blade is electrically connected with the line by the usual pigtail or flexible means 6. A fixed spring contact clip 7 is mounted on an insulator 8 fixed on the base 1, and is connected with the line by means 9.

The three switches are operated by the improved operating means of this invention,

which means includes a single rock shaft 10 mounted in suitable bearings 11 on the base members 1. The shaft is rocked by a crank 12. Crank arms 13 are carried on the rock shaft and are pivoted to links 14 in turn pivoted as at 15 to the movable switch members 2. By this toggle mechanism the three sw'tches are simultaneously operated from single rock shaft. The crank arms 13 and links are arranged so as to be on dead center when the switch is closed in order to n the imprqper seating tendency of the switch contacts occasioned when a torsional distortion is given the rock shaft, as will be later more fully explained.

I may use a means for counter-balancing the movable switch members 2, which means comprises on each switch phase, a crank arm 16 extending from the movable member 2 near its pivot and connected with one end of a retractile spring 17, the other end of which spring is fastened as at 18 to the base member.

Heretofore in rock shaft switches where the movable switch members are fixed to and are swung by the rock shaft, the rock shaft is usually comparatively long owing to the necessary forty or more inch spacing of the switch members on said shaft. The switch members on this shaft are usually long and heavy and this, with the length of the shaft, cause frequent torsional distortion of winding up of the shaft with the result that uncertain and improper seating of the switch contacts often occurs. A slight torsional distortion or wind up of this rock shaft may cause the blades to strike the bottom of the contact clip with damaging effect and so as not to properly contact with the clip. The more forceful or violent a closing action of this former type of switch, the greater the distortion or wind up of the rock shaft, due to the fact that the movable switch member on the shaft farthest from the operating crank, owing to the inertia thereof, will distort or wind up the shaft. Hammer blows of the blades on the clips are thus brought about with frequent damage and more frequent improper seating of the contacts.

With the switch of my invention the difiiculties and objections heretofore encountered are eliminated because the closed clip .ositions of the blade are definite and the roc ing switch members come to rest like the piston of an engine at the end of the piston stroke. This is due to the fact that when the switch is closed, the crank arms 13 and links 14 are on dead center, and therefore the resistance of the clips to the blades has no material effect on the angular distortion of the rock shaft. If however, it did have such an effect it would require considerable distortion of the rock shaft to eflect appreciably the position of the different blades when the switch is closed. Such distortion is most unlikely to occur in my switch construction as most of the distortion cause is removed by having the movable switch members mounted independent of instead of directly on said shaft. Irrespective of whether the switch is closed violently or gently, the position of the blades in the clips is identical and definite, thereby insuring proper engagement of the switch contacts. In case the clips adhere strongly to the blades after a period of disuse, the breaking of the toggle joints of the crank arms 13 and links 14 will exert a powerful starting force to free the blades from the clips with only a moderate pull on the crank 12.

One of the important considerations for a gang operated rock-shaft switch is to be assured of the alignment of blades and clips in each pole. Where switches of the conventional rock-shaft type are used with the insulators carrying the switch blades mounting directly on the rock shaft, the blades themselves are in mechanical alignment with the rock shaft so that with any distortion of the mountin structure or loosening of the holddown bo ts the blades will essentially align with the rock shafts, and the clips with the bases, so that any shifting will thus tend to make misalignment of the blades and clips. By mounting the rock shaft independent of the rocking insulators, as in Figures 1 and 2, any misalignment is taken up in the joints in the connecting rod, the blades and clips being in definite alignment from the nature of the construction. There is necessarily some lost motion in every bearing, and it is very essential for the proper results that the strains which are transmitted to the rocking insulator thru the connecting rod be transmitted in a direct line and substantially in the plane of the blades. Any other application of force to a rocking insulator will essentially twist the rocking insulator in the supports and tend to cause blade and clip misalignment.

The counter-balancing means operates so that when the line through the centers of the pivots 3, and the centers of gravity of the movable switch members are vertical, then the springs 17 pull directly on dead center and exert no turning movemet on the movable switch members. As soon as the center of gravity moves to either side of the vertical, the springs 17, act to counter-balance the weight of the movable switch members, and a greater pull of the spring is exerted as the angle between the center of gravity and vertical through the pivot center increase. In this way the weight of the movable switch parts may be balanced at all points of the stroke thereof to obtain an operating condition free from the strain of the weight of the movable switch members.

When the base 1 is in a horizontal position, the weight of the insulator and blade, which are to be counter-balanced, is proportionate to the sign of the angle between the vertical and a line through the insulator trunnion center and the center of gravity of the insulator with the blade. The torsional moment of the spring 17 is approximately proportionate to the sign of the corresponding angle, but from geometric considerations it will not vary as fast as the sign of said angle. When the line through the center of the pivot and the center of gravity of the insulator and blade is vertical. the spring pulls directly on dead center and exerts no turning moment on the pivoted switch member. However, the spring 17 being extended when the pivoted switch is off vertical center. of itself increases the spring tension and compensates for the decreased turning moment of the spring on the movable switch member so that substantially the spring may be made to balance the movable switch member in all positions.

I claim: 1. In an electric switch, a plurality of piv- 5 otally mounted switch blades, a plurality of fixed contact members into and out of contact with which the blades are movable, and means for simultaneously moving the blades into and out of contacting position, which 0 said means includes a single rock shaft and an individual crank and connecting rod connecting each blade with the rock shaft, said crank and said connecting rod being substantially on dead center when the switch is in 5 closed position.

2. In an electric switch, a plurality of normally fixed contact members, a plurality of separated contact blades mounted for simultaneous movement either into or out of engagement with the contact members, a single rock shaft, and a separate crank and connecting rod connected to and interposed between each blade and the rock shaft, said crank and said connecting rod being substantially on dead center when the switch is in closed position.

3. In an electric switch, a plurality of normally fixed contact members arranged in substantial alignment and in spaced relation to one another, a plurality of pivotally mounted spaced contact blades arranged in substantial alignment, each blade being adapted to engage with a different contact member, and means for simultaneously moving the blades either into or out of engagement with the contact members, which said means includes a common rock-shaft and a separate crank and connecting rod connecting each blade with the rock-shaft, said crank and said connecting rod being substantially on dead center when the switch is in closed position.

4. In an electric switch, a plurality of fixed contact members arranged in spaced relation to one another, a plurality of pivotally mounted insulators arranged in spaced relation to one another, a contact blade carried by each insulator each of which said blades is adapted to engage with a different contact member, and means for simultaneously moving the insulators, whereby the blades may be simultaneously moved either into or out of engagement with the contact members, which said means includes a single rock-shaft and a separate crank and link connecting each insulator with the rock-shaft, said crank and said connecting rod being substantially on dead center when the switch is in closed position.

5. In an electric switch, a plurality of fixed contact members, a plurality of pivotally mounted contact blades adapted to engage with the contact members, a single rockshaft, and a separate crank and link connecting each contact blade with the rock-shaft, 5 said links and cranks being substantially on dead center when said contact blades are in engagement with the said contact members.

6. In an electric switch, a plurality of fixed contact members arranged in spaced relation to one another, a plurality of pivotally mounted insulators arranged in spaced relation to one another, a plurality of contact blades one of which is mounted on each insulator, each of which said blades is adapted to engage a diiierent contact member, means for simultaneously moving said insulators whereby said blades may be simultaneously moved into and out of engagement with said contact members which said means includes a single rock-shaft and a separate crank and link connecting each insulator with said rockshaft, said separate cranks being mounted on said rock-shaft, said separate cranks and links being substantially on dead center when said contacts are in engagement.

AUGUSTUS J. BOWIE.

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