Electric Switches

Abstract

An electric switch has an actuating mechanism movable to any one of three positions. The mechanism engages a conductive arm in the form of a metal strip having downturned flanges which provide pivots about which the arm is moved by the actuating mechanism to interconnect pairs of contacts within the switch.

Description

This invention relates to electric switches and has as an object to provide a switch in a convenient form.

An electric switch according to the invention comprises a body, a switch actuating mechanism selectively movable within the body to any of three positions, a contact arm engaging said mechanism and a pair of contacts on the body respectively engageable by opposite ends of said arm, said arm having integral projections intermediate its ends, said projections being spaced in the direction of the longer axis of the arm and providing a pair of pivots for said arm on said body during movements of said arm to engage said pair of contacts respectively.

Switches according to the invention will now be described by way of example and with reference to the accompanying drawings in which:

FIG. 1 is a section through a switch,

FIG. 2 is a section on line 2--2 in FIG. 1,

FIG. 3 is a perspective view of a part of the switch of FIG. 1,

FIG. 4 is a section through an alternative form of switch, and

FIG. 5 is a perspective view of a part of the switch of FIG. 4.

The switch shown in FIG. 1 comprises a body formed in two parts 10, 11, part 10 being of a resiliently deformable plastics material adapted to engage both part 11 and a panel 12 with snap action. Part 11 is of insulating material and includes a wall 11a which supports eight contacts 13 arranged in two parallel rows of four.

A pair of conductive contact arms 14, only one of which is shown in greater detail in FIG. 3, have contact elements 15, 16 at opposite ends. Each contact arm 14 is formed with two pairs 17, 18 of turned-down flanges which extend as shown, from opposite sides of the arm 14 perpendicular to the remainder thereof. The flanges are of triangular form so that edges 17a, 18a of the pairs 17, 18 respectively provide pivots about which the arm 14 can rock in a manner later to be described. The arm 14 is also formed with a central transverse depression 19 and a pair of transverse portions 20 which extend from opposite sides of arm 14 in alignment with depression 19.

Pairs of projections 21 extend from the wall 11a of body part 11 and are spaced so as to receive arms 14, the portions 20 of arms 14 lying between the projections 21 in each pair thereof. Edges 17a, 18a of each of the arms 14 are respectively engageable with the inner pairs of contacts 13 in the associated row. Movement of arms 14 in the direction of their longer axes is prevented by transverse portions 20.

A switch actuating mechanism comprises levers 22 movable about a pivot 23 in body part 11. Arms 22 extend into body part 10 and carry a pair of spring loaded plungers 24 which engage the depressions 19 in the respective arms 14. Selected ones of the contacts 13 include terminal posts 25 which extend from the side of wall 11a remote from arm 14.

In use, movement of levers 22 by an integral toggle 26 causes arms 14 to be moved in unison to one of three positions. In the central position shown both edges 17a, 18a of both arms 14 are in engagement with the associated contacts 13. Anticlockwise movement of levers 22 as seen in FIG. 1, causes arms 14 to pivot about edges 17a to engage contact elements 15 with the corresponding contacts 13. Clockwise movement of levers 22 similarly causes arms 14 to pivot about edges 18a to bring contact elements 16 into engagement.

The alternative form of switch shown in FIG. 4 is generally similar to that shown in FIG. 1, but differs in details of the actuating mechanism and also in that the pair of contact arms 30, shown in greater detail in FIG. 5, are of a somewhat different form from those previously described.

Arms 30 have a pair of contact elements 31, 32 at each end, as before. Arms 30 have also a pair of downturned portions 33, 34 extending from opposite edges of the arm. Portions 33, 34 are formed with central outwardly extending tabs 35, 36 respectively, so as to define flanges 33a, 33b and 34a 34b respectively. These flanges conveniently have their ends radiused. Flanges 33a, 34a together form one pivot about which arms 30 can turn in one direction from its central position, and flanges 33b 34b form a further pivot about which arm 30 can turn in the other direction. Tabs 35, 36 are engaged between corresponding pairs of projections 21, as before.

The switch actuating mechanism comprises a pair of levers 37 and an integral toggle 38 pivotally mounted on body part 11. A pair of leaf springs 39 are of generally arcuate form and are formed at their ends with tongues 40 which are engaged in the respective arms 30. Springs 39 are formed with a central depression 42 in which a projection 43 on toggle 38 can locate when the latter is in its central position.

In use, the switch of FIG. 4 operates in a like manner to that of FIG. 1, the arms 30 and toggle 38 being movable to any of three stable positions in which contacts 13 are selectively interconnected.

Claims

I claim:

1. An electric switch comprising a body, a switch actuating mechanism selectively movable within the body to any of three positions, a contact arm engaging said mechanism and a pair of contacts on the arm respectively engageable by opposite ends of said arm, said arm having integral projections intermediate its ends with said projections being spaced in the direction of the longitudinal axis of the arm and providing a pair of pivots for said arm on said body during movements of said arm to engage said pair of contacts respectively, said integral projections comprising two pairs of flanges with the flanges in each pair being on opposite sides of said arm, said arm including a transverse depression intermediate the pairs of flanges, said switch actuating mechanism being engageable in use in said depression, said arm also including a pair of further projections extending transversely of the remainder of said arm on opposite sides thereof and being substantially aligned with said depression, and wherein said body includes pairs of projections between which said pair of further projections of said contact arm respectively extend, whereby longitudinal movement of said contact arm is prevented.

2. A switch as claimed in claim 1 in which said flanges extend substantially perpendicularly of the remainder of said arm.

3. A switch as claimed in claim 2 in which said flanges are of triangular form and define edges which comprise said pivots.

4. A switch as claimed in claim 2 in which said flanges have radiused outer ends which comprise said pivots.

5. A switch as claimed in claim 1 which includes a leaf spring whose ends are engaged with said arm adjacent the respective ends thereof, said leaf spring having a transverse depression intermediate its ends, and said depression being engageable by said switch actuating mechanism.