US3436499A - Inertia-operated switch - Google Patents

Description

April 1, 1969 -rs 3,436,499

INERIIA-OPERATED SWITCH Filed Dec. 21, 1967 j INVENTOR.

BY ame/a 45212 35 KWXM/ 4 7' TORNEY United States Patent US. Cl. 200-61.48 1 Claim ABSTRACT OF THE DISCLOSURE An electrical switch having a pair of spring biased normally open contacts maintained closed by a retaining arm member, rotatable about a pivot point, which is operable, upon the movement of an inertia weight, to open the contacts. A pawl located on one end of the retaining arm member is engaged by a trigger pin secured to the member which supports the inertia weight to maintain the retaining arm member in the position to close the switch contacts. Movement of the inertia weight will revolve the trigger pin out of engagement with the pawl, thereby permitting the force of the contact spring bias to rotate the retaining arm member about its pivot point and open the switch contacts.

This invention relates to electrical switches and, more specifically, to inertia-operated electrical switches.

Inertia-operated switches are well known in the art, however, heretofore, switches of this type have been cumbersome and included many moving parts.

'It is, therefore, an object of this invention to provide an improved inertia-operated switch.

It is another object of this invention to provide an improved inertia-operated switch having a minimum of moving parts.

In accordance with this invention, an inertia-operated switch is provided wherein the associated spring biased norm-ally open contacts are maintained in electrical contact by a cam surface on one end of a pivotally mounted retaining arm member which is locked in the position to maintain the contacts closed by a trigger pin secured to a resiliently mounted weight support member engaging a pawl on the other end thereof and are released to open upon the movement of a weight secured to the weight support member which rotates the trigger pin out of engagement with the pawl.

For a better understanding of the present invention together with additional objects, advantages and features thereof, reference is made to the following description and accompanying drawing in which FIGURE 1 is a front view of the inertia-operated switch of this invention,

FIGURE 2 is a section of FIGURE 1 taken along line 2-2 and looking in the direction of the arrows and FIGURE -3 is a section of FIGURE 1 taken along line 3-3 and looking in the direction of the arrows.

Referring to the figures of the drawing wherein like elements have been given like characters of reference in the three figures, the inertia-operated switch of this invention has a stationary electrical contact and a movable electrical contact 12 which is mounted upon a movable member 14 spring biased in a direction to open the contacts. With movable contact 12 in electrical engagement with stationary contact 10, an electrical circuit is established between conventional binding posts 15 and 16 through movable member 14. Movable member 14 may be made of an electrically conductive spring material to provide the necessary spring bias in a direction to open the contacts, as shown in the drawing, or

any alternate conventional spring biased movable contact arrangement may be employed.

The mechanism of the switch of this invention may be enclosed within a suitable. box like enclosure having a top cover 18, a bottom cover 19 and sides 20.

Re'siliently mounted within the enclosure is a weight support member 22, to which a weight 24 is attached, having two substantially parallel slots 25 and 26 symmetrical with the center line thereof and a trigger pin 28 secured thereto On the center line thereof for movable supporting weight 24.

Rigidly secured to enclosure member 18 are two stationary pins 30 and 31, each engaging a respective slot 25 and 26.

A spring member 34 is secured to the enclosure 20 and arranged to act upon trigger pin 28 in a direction which will force weight support member 22 in a directio which will locate the same selected end of each of slots 25 and 26 against the respective one of the stationary pins 30 and 31.

Pivotally mounted about pivot point 35 is a retaining arm member 38 having a pawl 39 on one end engageable with trigger pin 28 and a cam surface 40 on the other end which engages movable member 14, as is clearly shown in FIGURE 1.

The switch is operated by movement of weight 24. Movement of weight '24 to the left, as looking at FIG- URE 1, will produce rotation of weight support member 22 in a counterclockwise direction about fixed pin 31 to the extent permitted by the length of slot 25. Rotation in this direction will rotate trigger pin 28 out of engagement with pawl 39 which releases retaining arm member 38. With retaining arm member 38 thus released, the spring bias force of movable member 14, acting through cam surface 40, rotates retaining arm member 38 in a counter-clockwise direction about pivot point 35 and opens contacts 10 and 12 to interrupt the electrical circuit between binding posts 15 and 16. Movement of weight 24 to the right, as looking at FIGURE 1, will produce rotation of weight support member 22 in a clockwise direction about fixed pin 30 to the extent permitted by the length of slot 26 to rotate trigger pin 28 out of engagement with pawl 39 which releases retaining arm member 38. With retaining arm member 38 thus released, the spring bias force of movable member 14, acting through cam surface 40, rotates retaining arm member '38 in a counterclockwise direction about pivot point 3 5 and opens contacts 10 and 12 to interrupt the electrical circuit between binding posts 1'5 and 16. Movement of Weight 24 in a downward direction as viewing FIGURE 1 will also move trigger pin 28 out of engagement with pawl 39 to release retaining arm member 38 and permit the switch contacts to open in the manner herein explained.

Attached to retaining arm member 38 is a reset rod which extends through enclosure member 20 and is attached to a reset handle 46. As retaining arm member 38 is revolved in a counter-clockwise direction about pivot point 35 by the spring bias force of movable member 12 upon the disengagement of trigger pin 28 from pawl 39, reset rod 45 is moved to the right, as looking at FIGURE 1. To reset the switch, reset rod 45 is pushed to the left through reset handle 46 to rotate retaining arm member 38 in a clockwise direction about pivot point 35 by an amount sufficient to re-engage trigger pin 28 with pawl 39 to reset the switch mechanism for the next operation.

While the preferred embodiment of the present invention has been shown and described, it will be obvious to those skilled in the art that various modifications and substitutions may be made without departing from the spirit of the invention.

What is claimed is:

1. An inertia-operated switch having a stationary electrical contact and a movable electrical contact mounted upon a movable member spring biased in a direction to open the electrical contacts comprising, an enclosure, a weight, a weight support member having two substantially parallel slots symmetrical with the center line thereof and a trigger pin secured thereto on the-center line thereof resiliently mounted within said enclosure for movably supporting said weight which is attached thereto, first and second stationary pins secured to said enclosure and each engaging a respective said slot, a spring member secured to said enclosure and. arranged to act upon said trigger pin in a direction which will force said weight support member in a direction which will locate the same selected end of each of said slots against the. respective one of said first and second stationary pins and a retaining arm member mounted for rotation about a pivot point having a pawl on one end thereof engageable with said trigger pin and a cam surface on the other end thereof in engagement with said movable member upon which said movable contact is mounted for operating said movable contact into electrical engagement with said stationary contact against the force of said spring bias upon the rotation of said retaining arm member in a first direction about said pivot point.

References Cited UNITED STATES PATENTS 9 1,591,149 7/ 1926 Waltamath 200-615 2,130,706 9/1938 Salmond 200'61.5 2,223,097 11/ 1940 Ehret 2006 1.5 2,671,832 3/1954 Hansard et al. 200 6 1.5 X 2,879,349 3/1959 Thompson 20061.5 2,966,562 12/1960 McElvain ZOO- 61.5 2,986,614 5/ 1961 Minch 200 615 FOREIGN PATENTS 968,461 2/1958' Germany.

ROBERT K. SCI-LAEFER, Primary Examiner. ROBERT A. VANDERHYE, Assistant Examiner.

US. Cl. X.R. 20061.49, 61.5

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