GB2209874A - Electrical switch - Google Patents

Abstract

A waterproof electrical switch 1 has at least one pair of terminals 5, 11 connected by a rocker 20 pivotally mounted on one of the terminals 5. The rocker 20 is operated by a toggle assembly 30 carrying an actuating member 41 biased against the rocker 20 so as to pivot the rocker 20 between a first position (Figure 3) closing the switch and a second position opening the switch. The casing is moulded around the terminals 5, 11 and a waterproof seal is formed with epoxy resin 13 where the terminals penetrate the housing wall. An 'O' ring seal 39 is provided between the toggle assembly 30 and the housing. The rocker 20 comprises a pair of depending legs each having a V-shaped lower end for rocking on the terminal 5 and feet 25 received in apertures in the terminal for preventing lateral and longitudinal movement of the rocker 20. <IMAGE>

Description

ELECTRICAL SWITCH The present invention relates to an electrical switch and in particular to a waterproof switch, preferably of the double pole, single throw type.

The present invention provides a waterproof electrical switch comprising a housing, first and second terminals projecting through a wall of said housing and each having a contact part exposed within said housing and a terminal part extending outside of said housing, an electrically conducting rocker pivotally mounted in said housing in constant electrical contact with said contact part of said first terminal and arranged to pivot between a first position making electrical contact with said contact part of said second terminal and a second position out of electrical contact with said contact part of said second terminal, and a toggle arm assembly pivotably mounted in said housing and having an actuating arm extending through a wall of the housing and sealed thereagainst by an '0' ring, and an actuating member housed in said actuating arm and biassed against the rocker, said toggle arm assembly being pivoted between first and second positions to pivot said rocker between said first and second positions.

Other, preferred features and advantages of the invention will be apparent from the following description and the accompanying claims.

The invention will be further described by way of example with reference to the accompanying drawings, in which: Figure 1 is a plan view of a switch according to the invention; Figure 2 is an end view on arrow A of Figure 1; Figure 3 is a cross-sectional view on line III-III of Figure 2; Figure 4 is a cross-sectional view on line IV-IV of Figure 3; Figure 5 is an underneath view, partly cut away of the switch of Figure 1; and Figure 6 is a perspective view of a rocker of the switch of Figure 1.

Referring to the drawings, a switch 1 has a housing 2 comprising upper and lower halves 3, 4 moulded from plastics material.

A pair of first electrically conducting terminals 5 extend through a wall 6 in the lower housing half 4 and each have a contact part 7 and terminal part 8.

The terminals 5 have a toothed edge region 9 where they penetrate the wall 6 to lock them in place.

Terminal parts 8 extend through cylindrical arms 10 moulded with the wall 6. The arms may be filled with epoxy resin or like material to ensure a water tight seal where the terminals penetrate the housing wall.

The contact parts 7 have four cut outs 19 for receiving legs of a rocker as will be described hereinafter.

A pair of second electrically conducting terminals 11 extend through a wall 12 of the lower housing half 4 are sealed thereagainst by epoxy resin 13 or the like. The terminals 11 each comprise a terminal part 14 and contact part 15 and have a toothed edge region 16 to lock them in place in the wall 12.

The contact parts 7, 15 of the terminals 5, 11 are embedded in a bottom wall 17 of the lower housing half 4, their upper surfaces being exposed.

Referring to Figures 3 and 6 a rocker 20 rests on the contact part 7 of each terminal 5. Each rocker 20 comprises a plate part 21 and two downwardly depending legs 22. The lower end 23 of each leg 22 has a V-shaped edge 24 which is arranged to bear on the respective terminal contact part 7. A pair of feet 25 is formed at each end of the edge 24 and these are received in cut outs 19 formed at the sides of the contact part 7 (refer to Figure 3). A silver contact 27 is mounted on the underside of the upper plate 21. The rocker 20 may be stamped from copper alloy material and folded to shape.

The rocker 20 rocks on the edges 24 which bear on the exposed upper surface of the terminal part 7, the feet 25 cooperating with the cut outs 19 to prevent lateral or longitudinal movement of the rocker.

The rocker rocks from a first position as seen in Figure 3 in which electrical contact is made between first and second terminals, to a second position in which the contact 26 is lifted clear of the terminal The rocker is rocked and held in position by a toggle assembly 30 seen in Figures 3 and 4. The toggle assembly comprises an actuating arm 31 comprising a generally half cylindrical housing 32 having a hemispherical bulge 33 on its upper part and a pin 34 extending from the bulge 33 through an upper wall 35 of the upper housing half 3. The pin 34 extends through an elongate slot 36 in the wall 35. The housing 32 is snugly received between side walls 37, 38 of the upper housing part 3. The hemispherical bulge 33 is received in a recess in the underside of the upper wall 38 and bears against an '0' ring 39 held in a circular groove 40, forming a water tight seal.

A piston-like actuating member 1 is housed in the housing 32 and biassed against the two rockers 20 by a centrally located coiled spring 42 which is received in a blind bore extending into the bulge 33. The actuating member 41 has a V-shaped lower end 43. As seen in Figure 3, one side 44 of the V-shaped end bears against the rocker arm 20 when the switch is closed, as shown. To open the switch, the pin 34 is pivoted to the left of Figure 3. The actuating member 41 is urged back into the housing 32 against spring 42 as it rides along the upper plates 21 of the rocker arms 20. The rocker arms 20 will pivot over to their second positions, opening the switch, the other side 45 of the member 41 bearing on the rockers 20.

To assemble the switch the lower housing half 4 is moulded with the terminals in position. The rockers 20 are placed on the terminals 5 and the toggle assembly 30 is assembled in the upper housing half 3. The housing halves are then brought together and ultrasonically welded to form a waterproof joint. In use the switch may be installed in an appliance and terminals 5 being connected to a line cord from a power supply. Preferably the line cord is connected by soldering and the connection is then enclosed in epoxy resin and an outer sheath of heat shrink tubing.

Various modifications ...ay be made to the described embodiment and it is desired to include all such modifications as fall within the scope of the accompanying claims.

Claims (8)

1. A waterproof electrical switch comprising a housing, first and second terminals projecting through a wall of said housing and each having a contact part exposed within said housing and a terminal part extending outside of said housing, an electrically conducting rocker pivotably mounted in said housing in constant electrical contact with said contact part of said first terminal and arranged to pivot between a first position making electrical contact with said contact part of said second terminal and a second position out of electrical contact with said contact part of said second terminal, and a toggle arm assembly pivotably mounted in said housing and having an actuating arm extending through a wall of the housing and sealed thereagainst by an '0' ring, and an actuating member housed in said actuating arm and biassed against the rocker, said toggle arm assembly being pivoted between first and second positions to pivot said rocker between said first and second positions.

2. A switch as claimed in claim 1, having a pair of first terminals, a pair of second terminals, and a pair of rockers, each rocker being associated with a respective first and second terminal.

3. A switch as claimed in claim 2, wherein said rockers are pivoted by a common toggle arm assembly.

A A switch as claimed in claim 1, 2 or 3, wherein a said rocker comprises an upper plate and a pair of legs depending down from longitudinal sides of said upper plate, said legs each having at their lower ends an edge arranged to rock on a respective contact part of a said firt terminal and a pair of feet arranged to be received in apertures or recesses in said contact part to prevent said rocker creeping during use of the switch.

5. A switch as claimed in claim 4, wherein said upper plate carries a contact for making electrical contact with a respective contact part of a said second terminal when said rocker is in the first position.

6. A switch as claimed in any one of claims 1 to 5, wherein said first terminal is adapted to be connected to a power supply lead.

7. A switch as claimed in claim 6, wherein said first terminal extends through a sleeve integrally formed on said housing.

8. A waterproof electrical switch substantially as hereinbefore described with reference to the accompanying drawings.