US1939286A - Switch - Google Patents

Description

Patented Dec. 12, 1933 UNITED STATES PATENT OFFICE,

SWITCH Application September 6, 1930. Serial No. 480,154

B Claims.

This invention relates to switches, and with regard to certain more specific features to 'contacts for switches.

Among the several objects of the invention may be noted the provision of a resiliently mounted contact which has a general application, but which also has a particularly advantageous application to switches having two or more contact points, especially snapping disc types; the provision of a contact of this class which tends to equalize contact pressure and its resulting eiect upon that which supports said contact; and the provision of a device of the class described which is compact in form and which may be simply fabricated. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structure hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawing, in which is illustrated one of various possible embodiments of the invention,

Fig. 1 is a cross section showing a switch with the invention applied thereto;

Fig. 2 is a plan view of Fig. 1, a cover being removed; and,

Fig. 3 is a cross section taken on line 3 3 of Fig. 2.

Similar reference characters indicate corresponding parts throughout the several views of the drawing.

This invention comprises an improvement upon the contact shown in my Patent 1,697,886, dated January 8, 1929 and assigned to Spencer Thermostat Company of Cambridge, Massachusetts.

Referring now more particularly to Fig. 1, there is illustrated at numeral 1 a switch base assembly carrying line` terminals 3 arranged to close a circuit 5 when gaps 7 therebetween are closed by contactors 9, said contactors 9 being mounted upon a snap-acting plate or bulged disc 11.

The disc 11 is supported for vertical movement on a vertically reciprocable pin 13. Vertical movement of the pin 13 is effected by a part connected at 15 but not shown. A cover 17 over the disc 11 carries a reaction fulcrum or projection 19, circular in form. Upward movement of the pin 13 causes the bulged disc 11 to strike the projection 19, causing the disc to be thrown to a reverse curvature from that shown, this taking place with an over-centering snap-action and setting up a reaction at the fulcrum 19 and between the contactors 9 and line terminals 3, thus suddenly closing the circuit. Opening is accomplished by drawing down the pin 13, whereupon the increased reaction at the contacts 9 sets up a. 50 reversal of curvature so that the disc 11 snaps to the shape shown. thereby opening the circuit.

A pin 21 ensures proper allocation of the contacts and circuit gaps.

The device above described comprises a multicontacter switch in which the contactors are carried on a resilient member (disc 11) of such a nature that for most perfect operation it should not be eccentrically sprung, as for instance by uneven contact pressure. In order that perfect and even contact maybe had at each of the plurality of contacts, they are built and applied as follows:

Suitable openings 23 are placed through the disc 11 at the proper locations for the contacts. Extending through each opening 23, with ample clearance is a tapering stem 25 which forms an extension from a button 27, the button carrying between it and the disc 11 a mica or other insulating washer 29, the opening in the washer being such that before upsetting a head 31 on the 80 stem 25, the washer 29 will force thereover with a tight t, as shown. After application of the stem 25 with its applied washer 29, a second similar washer 30 is applied above the disc 11. Then a metal washer 33 is applied and the extension 25 85 upset as shown at numeral 31. The upsetting forces the metallic washer 33 to the inverted conical shape shown, or that washer may initially be given such a shape. The riveting clamps together the button 27 and washer 33, thereby 90 forcing together the mica washers 29 and 30 and thus insulating the contact 9 from the disc 11.

It is preferable that the upsetting 'be done under heated conditions (preferably electrically) so that the mica is caused to take its shape better. Inasmuch as the switch nally operates under high temperature condition, this insures that the clearances are adapted to operating conditions.

On its lower face, the button 2'7 is provided with 100 an extension 37. This extension passes slidably and loosely through the contact 9. The looseness permits swiveling of the plate. A head 41 prevents the plate 9 from falling oi.

On the upper face of the plate 9 is peripherally 105 fastened autogenously or by soldering or the like a metal cupped or arched spring 39, which is herein shown as a bulged disc reacting against the button 27. Operation is as follows:

When the switch is in open position (Figs. 1 110 and 3), the spring 39 reacts against the button 27 tol take up lost motion and set the contact' 9 in a definite and predetermined position.

's es When the switch closes, one contact may strike, before another. In this event its spring disc 39 is pressed flat, or substantially so, to permit alignment. the head 4l moving down from the contact Furthermore, the invention prevents the con-- tacts from hanging indifferently on their 'necessarily swiveljoints and ensures that allcontacts will bel made substantially at once. This is because of the springs 39 accurately'predetermining the positions of the contacts. f v

e Another feature is that the spring 39 itself has a characteristic quick action which, when the main disc 11 is snapping up, maintains contact until the snap action of spring 39 carries the contact quickly and finally from the line terminals ,3,l thus providing a quick break with minimum y arcing.

The spring 39 has a relationship between displacement and force wherein the force decreases with displacement so that it takes less force to hold the spring 39 against the-contact 9 than to start its displacement toward a flat condition. Thus the kinetic energyinthe main discll at snapping is used for starting and finishing deiiection of the spring 39 but after closure of the switch (under static conditions) only a small force is required to hold down the spring 39. Thus there is not a substantial tendency to force the main disc 11 to snap back when it should not (as at a wrong temperature), as would be the case were a coil or other conventional type of spring used which requires increasing force for increasing displacements thereof. Another way of stating this feature is that it required less force to hold the spring 39 in a substantially, iiat or strained position (as when the switch is closed) than it does to drive it from its cupped or unstrained position (as when the switch is open). Likewise less force is required for maintaining any comparativelymore strained position than any comparatively less strained position. Thus it functions llike a snap acting or quick vacting'cupped disc which does not over-center.

The simplicity of construction and the compactness thereof is evident, the whole'taking up substantially no more space than a springless type. o i

In view of the above, it will be seen that the several objects of the invention are achieved andother advantageousresults attained.

As many changes could be made in carrying' fbe interpreted as .illustrative and not in a limiting sense. v

vIV claim: l 1 1'. A switch comprising vline contactseiecting at least one gap, at least one contact therefor,

means for driving the contact-into engagement and at least one spring between the driving means' and said contact, said spring being characterized by requiring less force to hold it in a substantially strained position than to distort it froma predetermined less, strained position and comprising a member shaped to join the contact at spaced points and being arched between said points, the driving means drivingl the spring from above and against said arch.

2v. Aswitch comprising line contacts effecting at least one gap, at least one contact therefor. means for driving the contact into engagement and at least one spring between the driving means and said contact, said spring being characterized by requiringless force to hold it in a substantially strained position than to distort it from a predetermined less strained position and comprising an arched disc joined peripherally to the contact, said driving means driving the disc.

3. A switch comprisingfa main snapping disc,`

a plurality of contacts, swivel means for holding said contacts to the disc and resilient means for predeterminately positioningl each contact.

4. A switch comprising a main snapping disc, a plurality of contacts, swivel means for-holding said contacts to the disc and resilient means. for predeterminately positioning each contact comprising resilient means between each contact and its holding means.

5. A switch comprising a main snapping disc, I a plurality of contacts, swivel means for holding f ing a quick-acting, bulged spring engaging its respective contact at spaced points.

7. A switch comprising a main snapping disc, a plurality of contacts, swivel means for holding said contacts to the disc and resilient means for predeterminately positioning each contact comprising resilient means between each contact and its holding means, said resilient means comprising a quick-acting, bulged-disc spring peripherally engaging said contact.

8. A switch comprising a main snapping disc,

a plurality of contacts, swivel means for holding said contacts to the disc and resilient means for predeterminately positioning each contact comprising resilient means between each contact and its holding means, said resilient means comprising a quick-acting, bulged-disc spring peripherally engaging said contact, the contact having a swiveling connection with the holding means.

JOHN A. SPENCER.

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