US1915991A - Electric switch - Google Patents

Description

June 27, 1933. H. J. HAMMERLY 1,915,991

ELECTRIC SWITCH I Filed July 29, 1930 2 Sheets-Sheet 1 INVENTOR be inspected or removed from the front of Patented June 27, 1933 J1; LY, OF WALLINGFOBD, CONNECTICUT, ASS IGNOB TO THE TBUI- BULL ELECTRIC MANUFACTURING CORPORATION OF CONNECTICUT comrmfor PLAINVILLE, oor m'ac'rmur, A

ELECTRIC SWITCH Application fled July 29, 1880. Serial 1T0. 471,471.

My present invention relates to certain improvements in the construction and operation of electric circuit breaking switches of the type which are usually enclosed in'protective casings or boxes and provided with external operating handles, this type of switch being commonly known as enclosed switches. v

My invention relates articularl to the combination of elements or the ma 'ng and breaking of the circuit in a novel and efficient manner.

The principal object of my invention is to provide a very com act and efficient switching means for brea g the circuit at four points in each leg of the circuit to be controlled.

Another object is to provide a switch hav- 26 ing centrally pivoted blades so arranged as to be specially well adapted for operation by a correlated quick-ma e and quiclsbreah means.

Another object is to provide a switch con-. struction in which the movable blades are loosely mounted to provide for a self-adjusting ring engagement with the correlated stationary contacts.

Another object is to provide a switch construction in which the blades move away from the stationary contacts in two directions during the arcing possibility period of movement.

Another obj eat is to provide a switch having a pair of movable blades arranged to form substantially a split pivoted disc and to cause the same to engage the stationary contacts with a self-adjusting, rotary wiping contact.

Another object is to provide a switch having reversible stationary contacts which may the switch without disturbing other correlated elements. a

Another object is to provide a switch construction in which themovement and correlation of the contacts is suchthata fresh and comparatively cool ortion of the movable contact is constant y presented at the possible arcing point or, in other words, so

so that the arcing point-of the movable contact is constantly changedduring the circuit opening movement of the switch.

Another object is to so design and operate the contacts of a switch that, during the possible arcing period of the switch movement, a movable contact of flat and comparatively heavy metal will move only a comparatively short distance away from vthe stationary con tact so as tofunction .as a bafile to the arc by limiting the open air space between the movable and stationary contacts.

Another'objec't is to provide a switch in which the contacts can not be stuck or frozen together as is possible in the usual knife blade type of switch.

Fig. 1 is a front view of the switch embodymg the improvements of my invention, the parts being shown in the open circuit and broken away.

Fig. 2 is a transverse sectional view same.

Fig. 3 is a side view of the switch plu and position and the cover of the box bein'g'open '0 tr the contact'mechanism, the shaft being own 76 in section.

Fig. 4 is a longitudinal sectional Fig. 5 is an exploded 1:; showmg parts of the switch mec I Fig. 6 is a view showing the parts in one view.

of the positions they occupy while breaking the circuit.

The switchbase 10 is preferably'of suitable molded insulation and it can be secured in a box 11 by one or more screws 12 in the usual manner.

The switch may be designed to take care of any number of circuits or oles of a circuit, as for instance, a switch or contro a double pole circuit as herein shown. t

will only be necessary, however, to describe no a single unit. The stationary contacts 15 and 16 are secilred to the base, for instance,

to permit it to oscillate. For this purpose any suitable form of actuating mechanism may be employed as for instance the external handle 20 with the internal throwing spring 21, and rocker arm 22 actuated by the handle through a lost motion connection. The plate 23 is secured on the end of the shaft 19 and has an extension pin 24 co-acting with the rocker 22. v

The movable blades 26 and 27 are preferably in the form' of semi-circular plates which are mounted on a square hub 28 on the disc29 which is slidably mounted on the shaft 19 and has a sleeve 30 '"which slides in a bearing 31 in the post32 which is a part of the base. A second disc 33 is also slidable on the shaft 19 and is pressed by the spring 34 toward the switch blades 26 and 27.

Pins 35 and 36 are carried by the disc 28 and have shanks which extend into openings 37 and 38 in the plates 26 and 27. These pins 35 and 36 co-act with inclined cam- like shoulders 39 and 40 and with stop shoulders 41 and 42. The discs 28 and 33 are of insulating material.

In the closed circuit position a spring 34 holds the switch blades pressed against stationary contacts and 16. It will be seen that each of the blades or plates 26 and 27 carries only one-half of the current. To open the circuit the switch handle is pulled down and the shaft 19 rotated counter-clockwise as viewed in Figures 3 to 6. This rotativemovement causes the ins and 36 to ride up the inclined sur aces 39 and very quickl after rotative movement has been. starte The inclines 39 and 40, however, dq not begin at the shoulders 41 and 42 but a certain clearance is left so that the contact plates rotate through a considerable angle before they begin to move away from the stationary'cont'acts. The result is that when the circuit is broken the switch blades are not only rotating in the plane of the stationary contact faces but they are also traveling longitudinally of the shaft 19 away from the stationar contacts thus effectin 9. o break at each en of each of the mova le switch blades as they separate from the respective stationary contacts. This compound action serves as a very effective method of interrupting the arc and preventing injury to the contacts and the switch parts. N r

At the moment of breaking the circuit, the tip 43 of plate 26 is still in full contact with contact 16 and the tip 44 of plate 27 is still in full contact with contact 15, thus the tendency of the arc would be to jump from contact 15 to tip 45,-from contact 16 to tip 46 and from plate 26 to plate 27 along the lines of separation but as the opening movment continues, plates 26 and 27 move later ally away from contacts 15 and 16 thus making two more breaks or four in all.

The rotary movement of the plates 26 an 27 causes a fresh portionof the plates to be curs in the reverse direction so that the contacts are brought together with a sliding and snap action thus keeping the contact surfaces bright and free of corrosion or carbon.

The switch blades 26 and 27 are more or less loosely mounted on the shaft 19 so that they are able to adjust themselves to the stationary contact surfaces and thus provide substantial and perfect contact even though the" stationary contacts may be slightly out of alignment. The convex bearing surfaces of the stationary contacts also aid in providing perfect contact.

I have shown a latch 50 of a typical form for holding the cover closed and it will be understood that interlocking mechanism might be employed as is commonly done in enclosed switch constructions.

I. claim:

1. An electric switch including an insulating base having a post projecting at substantially right angles thereto and having a stop shoulder with an inclined approach, a pair of stationary contacts mounted on opposite sides of said post, a rotatable shaft supported in said post between said'stationary contacts, a switch member rotatably carried by said shaft and slidable longitudinally thereon toward and from the post, and means for rotating said shaft and switch member and -moving said switch member longitudinally of the shaft as it is rotated, ineluding 'a spring for pressing the switch member toward the stationary contacts and a projection meeting with the inclined approach' for moving the switch member away from the contacts as the switch rotated.

2. An electric switch comprising an insulating base having projecting posts, a shaft member is v rotatably supported in said posts, stationary contacts mounted on opposite sides of said support and rotatable .therein, an insulating carrier mounted on said shaft, a air of spaced contact plates carried by sai insulating carrier, and projecting members stop shoulders.

carrier rotatable with said shaft and slidable thereon and having a projection adapted to coact with said shoulder and said inclined approach, a switch member carried by said carrier and adapted to engage said contacts, a spring arranged to force said carrier so that 'theswitch member is resiliently pressed toward said contacts,'and

snap action mechanism coacting with said shaft to rotate the shaft and switch member, said stop shoulder serving to limit the rotation of the switchmember toward the closed circuit position and the inclined approach and rojection coacting to retract the switch mein r when moving the switch to the open circuit position.

5. In an electric switch, a pair of spaced apart stationary contacts, a rotatable shaft, a switch member carried thereby and adapted to close the circuit through said contacts,

a spring for forcing said switch member toward said contacts, a cam, -means coacting therewith to move the switch member laterally away from the contacts when the switch member is rotated, snap action mechanism having a lost motion connection with the shaft for rotating the shaft and switch action mechanism. Y

member for closing and o I the circuit with a snap action, and means for supporting the contacts and the shaft and snap 6. In anelectric switch, an insulating base, apair of stationary switch contacts mounted on said base, a rotating shaft mounted on said base between said contacts, an insulating carrier mounted to rotate with said shaft, two rigid semi-circular spaced apart switch plates mounted on the insulating carrier in a common plane and rotatable with said carrier, snap action and cam mechanism for simultaneously rotating said insulating carrier and said plates and moving said plates laterally with respect to said stationary contacts as said shaft is rotated, and a spring tion of said contacts.

of rigid flat semi-circular rotatable switch plate contacts spaced apart from each other and having their ends engageable simultaneously with said stationary contacts so that each plate contact carries onl one-half of the current, mechanism for simultaneously movin said rotatable contacts rotarily and lateral y away from the said stationary contacts, and a spring separate from said mech- 7. In a switch, a pair of stationary contacts having convex contactsurfaces, a pair' separate from the snap action mechanism for pressing the insulating .carrierin the direcanism for pressing the plate contacts toward the Estationary contacts.

HERMAN a. HAMMERLY.

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