US2360670A - Electric switch - Google Patents

Description

E. F. GOETZ ELECTRIC SWITCH Oct. 17,1944.

Filed May 6, 1943 Inventor: Ernest west-z b ,VWZKJ 1 Hi A ttorney.

Patented Oct. 17,

ELECTRIC SWITCH Ernest F. Goetl, Schenectady, N. Y., assignor to General Electric Company,

New York a corporation of Application May 6, 1943, Serial No. 5,873

6 Claims.

My invention relates to electric switches, more particularly tocutout switches, and has for its object a simple and reliable operating mechanism forlimiting the speed of movement of the switch member to a predetermined desirable speed when the operating member is moved at a higher speed.

My invention is especially related to auxiliary small control or interlock switches which are operated by the movable armature of a magnet when the armature approaches its final picked up position. The control switch to which my invention relates may, for example, be in circuit with the operating coil of the armature so as to insert a current limiting resistance in the circuit of the coil when the armature has picked up. When the operating armature is fully loaded, its speed may not be great enough to damage the control or interlock switch. I have found, however, that when the armature does not have applied to it the load which it is designed to operate, the armature accelerates to a very high speed before reaching its fully attracted position, and these high speeds produce excessive vibration in the contact arm of the auxiliary switch, causing it to break.

In accordance with my invention, I provide an operating member for the auxiliary switch which is engaged by the operating armature and which is movable independently of the auxiliary switch. This operating member is biased by a comparatively heavy spring force to a predetermined switching position, and the switch arm of the auxiliary switch is biased against the operating member by a weaker spring which will accelerate the switch arm to a predetermined maximum operating speed which does not damage the switch arm. Thus, in the operation of the device the operating member may be moved at a very high speed by the armature of the magnet, but this high speed movement takes place independently of the switch arm which is movedv by the weaker spring at a lower speed without damage to the switch arm.

For a more complete understanding of my invention, reference should be had to the accompanying drawing in which Fig. 1 is a front elevation view with the cover removed of a switch embodying my invention; Fig. 2 is a sectional view taken along the line. 2-2 of Fig. 1 looking in the direction of the arrows and showing a cover in place; Fig. 3 is a sectional view along the line 3-3 of Fig. 1 looking in the direction of the arrows; Fig. 4 is a sectional view along the line 4-4 of Fig. 2 looking in the direction of the arrows; while Fig. 5 is a view in perspec-- tive of a bridging contact member embodied in the switch.

Referring to the drawing, in carrying out my invention in one form I provide a metallic operating member in pivotally mounted on a fixed pivot l I on supports l2 and I3 secured to a metal base I4. One arm Illa of this operating member extends through an opening I5 in the base to the exterior where it is engaged for operation of the switch by a projection or arm l6 attached to the lower end of the plunger type armature II. The armature is shown in its unattracted position. When it is picked up upon the energization of a conventional coil (not shown) the arm it engages the part Illa and moves the operating member l0 counterclockwise about the pivot H, as seen in.Fig. 2, until the portion 10a is near the upper wall oi the opening I5.

The portion of the operating member Ill adjacent the pivot II is provided with two spaced apart flanges l8 and is which may be integral with the arm Illa. Secured to these flanges integrally, as by welding, are two spaced plates 20 and 2| joined together by a cross or bottom portion 22 provided with an aperture 23. A pin or bolt 24 has its right-hand end, as seen in Fig. 2, secured to the inner side of the base I4 and extending toward the left at right angles therewith centrally through the aperture 23. Surrounding the bolt'24 on the left-hand side of the cross member 22 forming part of the operating member I0 is a relatively strong helical spring 25 having one end bearing on the cross portion 22, and its other end bearing on a fixed spring seat 26 on the bolt. As shown, the bolt extends through an aperture provided for it in an enclosing cover 21 on the exterior of which it is provided with a nut 28 to hold the cover in place on the base. At the top a similar bolt 29 is provided but solely for the purpose of holding the upper end of the cover in place.

This relatively strong spring 25 applies a correspondingly strong force tending to move the operating member I0 clockwise about its pivot and normally holds the arm Illa against the lower edge of the opening l5, which edge acts as a stop for the operating member. Thus, as the armature l'l moves upward, the operating member is moved counterclockwise at a speed corresponding with the speed of the armature, the spring 25 being compressed. This operating member, however, is rugged and compact enough so that it is not damaged by the most severe high speed operating conditions imposed by the magnet when' it is operating a very light load.-

Also mounted pivotally on the stationary pin II is a switch arm I. made oielectricallyinsulating material, such as a molded phenolic product. This arm II is provided with an aperture II through which the bolt 24 extends loosely so that the switch arm, as well as the operating member 22, can move pivotally without engaging the bolt. It is also provided with a recess 32 in its right-hand side, as seen in Fig. 2, surrounding the bolt 24, in which recess is a relatively weak helical spring 33 surrounding the bolt and having its right-hand end bearing on. the base l4 and its left-hand end bearing on the switch arm so as to appl a counterclockwise force to the switch arm and hold it against the cross portion 22 of the operating member, the switch arm being provided with a flat surface engaging this cross portion. Also, the lower end of the switch arm 30 is provided with an extension 34, partly cylindrical, provided with an aperture through which the pivot pin I I extendsand lying between the two parallel plates 20 and 2| oi the operating member.

At its upper end the switch arm 30 has secured to it a rigid metal support 35, shown more clearly in Fig. 5, on which is mounted a bridging contact or switch member 36. This bridging contact has switch contacts 31 and 3! 'on its opposite ends which are movable into engagement with stationary contacts 39, only one of which is shown, mounted on the ends of electrically conducting supporting members." and 4|. 7

As shown, the contact supporting members 40 and 4| are mounted on projections or ledges provided for them in an insulating support 42 made of a suitable molded electrically insulating material, and held inplace by screws as shown. This support 42 has a supporting back wall 43 lying against the support I4 and secured to the support l4 by suitable screws 44 and 45 (Fig. 4), and additional screws 46, only one of which is shown. It is provided with two walls 41 and 48 extending outward from the base on opposite sides of the switch arm 30 and loosely embracing the switch arm, together with two higher walls 49 and 50 on the outside. Between the walls 4! and 49 is the ledge i (Fig. 4) forming the support for the contact support 40, while a similar supporting ledge is provided between the walls 48 and 50 for the contact support 4 I.

Also, the outside walls 49 and 50 are extended around the movable and stationary contacts to form an upper portion or wall 52 which surrounds the stationary and movable contacts. The back wall 43 is extended and joined with this upper wall portion 52. This upper wall portion forms an enclosure in which all arcing takes place and in which the arcs are suppressed.

bends and an oilset connecting portion near its middle. The relation 01' this supportwith the contact supports 4. and 4| is such that the movable and stationary contact supporting parts can be removed and put inplace again in reversed positions to change the switch from a, normally closedone, as shown in the drawing, to a normally open one. Thus,'when the support 35 is reversed, the offset portion brings the bridging contacts behind the stationary contact supports 40 and 4|, and these latter supports then need only be removed by removing. their holding screws, turned over to bring the contacts 31 and 38 into engaging position with the bridging contacts, and then secured again by the screws.

Thus, as previously stated, the operatingmember l0 can be moved without damage to it at any excessively high speed about the pivot II, the

spring 25 being compressed. The switch arm 30,

however, follows at a lower speed determined by the strength of the relatively weak spring 33, the strength of this spring being chosen to assure a maximum speed of operation ofv the switch arm which does not damage it. I have found that, with the contact support 35 rigidly connected to the operating member I 0, after a few hundred thousand operations at excessively high speeds, the contact support 35 broke, apparently by reason of excessive vibration. In this particu-v lar case, no damage was caused by excessive hammering of the contacts.

While I have shown a particular embodiment of my invention, it will be understood, of course, that I do not wish to be limited thereto since many modifications may be made, and I therefore contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

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

As shown in Fig. 5, the bridging member 36 is provided at its middle with a laterally ex l. A switch comprising an operating member mounted for movement, a first means biasing said operating member to a predetermined position, said first means yielding to provide for high speed movement of said operating member in one direction, a switch member movably mounted adjacent said operating member, and means biasing said switch member against said operating member with a force smaller than the opposing force of said first means and for moving said switch member in said direction at'a maximum predetermined speed independently of said operating member in the event of movement of said operating member in said direction at a speed higher than said predetermined speed.

2. A switch comprising an operating member mounted for movement; a stop for said operating member, a first spring biasing said operating member against said stop, said first spring yielding to provide for high speed movement of said operating member in one direction, a switch member movably mounted adjacent said operating member, and a second spring for biasing said switch member in said direction against said operating member with a force smaller than the opposing force of said first spring and for moving said switch member in said direction at a maximum predetermined speed independently of said operating member in the event of movement of said operating member in said direction at a speed higher than said predetermined speed.

3. A switch comprising an operating member mounted for movement about a fixed pivot, a stop for said operating member, a relatively strong spring biasing said operating member against said stop, said spring yielding to provide for high speed movement of said operating member, a switch arm pivotally mounted adjacent said operating member, and a relatively weak spring for biasing said switch arm against said operating member and for moving said switch arm at a maximum predetermined speed independently of said operating member in the event of movement of said operating member away from said switch arm at a speed higher than said predetermined speed.

4. A contactor comprising a fixed pivot, an operating member mounted on said pivot, a stop for said operating member, a relatively strong spring biasing said operating member to a predetermined angular position against said stop, a switch arm pivotally mounted on said pivot, a relatively weak spring biasing said switch arm against said operating member for moving said switch arm at a predetermined maximum speed about said pivot thereby to limit the speed of said switch arm when said operating member is moved away from said switch arm at a higher speed, a movable electric contact carried by said switch arm, and a stationary contact cooperating with said movable contact.

5. A switch comprising a fixed pivot, an operating member mounted on said pivot at a point intermediate its ends, a stop for a first arm of said operating member, a first helical compression spring having one end bearing on a second arm of said operating member thereby to apply a force tending to move said operating member about said pivot until said first arm is brought to rest against said stop, a switch arm mounted on said pivot and extending along the side of said second arm opposite said first spring, a second helical compression spring having one end bearing on said switch arm so as normally to hold said switch arm against said second arm of said operating member with a force smaller than that applied to said second arm by said first spring and for moving said switch arm at a predetermined maximum speed independently of higher speed movement of said operating member away from said switch arm, a movable contact carried by said switch arm, and a stationary contact cooperating with said movable contact.

6. A switch comprising a fixed pivot, an operating member mounted on said pivot at a point intermediate its ends, a stop fora first arm of said operating member, the second arm of said operating member being provided with an aperture, a stationary rod extending through said aperture in a direction substantially at right angles with said pivot, a first helical compression spring on said rod having one end bearing on said second arm thereby to apply a .force tending to move said operating member about said pivot until said first arm is brought to rest against said stop, a switch arm made of electrically insulating material mounted on said pivot and extending along the side of said second arm opposite said first spring, a second helical compression spring surrounding said rod and having one end bearing on said switch arm so as normally to hold said switch arm against said second arm of said operating member with a force smaller than that applied to said second arm by said first spring and for moving said switch arm at a predetermined maximum speed independently of higher peed movement of said operating member away from said switch arm, a metal contact carrying member on the movable end of said switch arm, a movable contact carried by said member, and, a stationary contact cooperating with said movable contact.

ERNEST F. GOE'I'Z.

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