GB2374981A

GB2374981A - Waterproof switch

Info

Publication number: GB2374981A
Application number: GB0110179A
Authority: GB
Inventors: Terence P Waite
Original assignee: Arcolectric Switches PLC
Current assignee: Arcolectric Switches PLC
Priority date: 2001-04-25
Filing date: 2001-04-25
Publication date: 2002-10-30
Also published as: GB0110179D0

Abstract

An electrical switch includes a body member 102, a switch member 104, 106, and a base member 112. The components provide inner and outer compartments. The inner compartment (164, Fig 3) is watertight and houses the electrical contacts of the switch and the outer compartment has openings 132, 134 for ingress and egress of fluid. The switch can be a single pole rocker switch or a twin rocker switch.

Description

AN ELECTRICAL SWITCH This invention relates to the field of electrical switches, for example rocker switches.

Rocker switches are used in a wide range of situations in electric and electronic appliances. Switches may need to be used in environments which are damp, humid or exposed in some way to water or liquid. Safety requires that switches used in such environments should be protected from the ingress of the water, water vapour or other liquids.

It is known to have switches with waterproof covers which snap-fit over the top of the switch. The covers may formed of a first rigid element applied to the edge of the switch and a soft P. V. C, or polyurethane element moulded over the rigid element bonding it to the harder piece. The soft element adheres to a wall, for example of an appliance, surrounding the switch with the aim of providing a watertight seal.

Such known switch covers have the disadvantages that the seal depends on the surface of the surrounding wall and a flush fit of the switch in the wall. They may also be unsightly.

It is an object of the present invention to provide an improved switch which allows water into a body of the switch but not into the internal electrical contacts of the switch.

According to the present invention there is provided an electrical switch comprising the components of a body member, a switch member and a base member, the components providing inner and outer compartments, wherein the inner compartment is watertight and houses the electrical contacts of the switch and the outer compartment has openings for ingress and egress of fluid.

Preferably, the base member locates a plurality of terminals of the switch. The base member may have a watertight snap fit attachment to the body.

The switch may be a twin rocker switch. Alternatively, the switch may be a single pole rocker switch.

Optionally, the switch may an illumination means for indicating the position of the switch.

Preferably, the body member has spring biased locating arms for locating the body of the switch in a cavity.

Embodiments of the invention will now be described, by means of example only, with reference to the accompanying drawings in which: Figures 1 a, 1 b and 1 c are plan, side and front views of a twin switch in accordance with the present invention with one switch in an on position and one switch in an off position ; Figure 2 is a perspective view of the twin switch of Figures 1 a, 1 band 1 c ; Figure 3 is a cutaway view of the twin switch of Figures 1 a, 1 b and 1 c through the switch in the on position; Figures 4a and 4b are part sections of a switch in accordance with the present invention, the switch of Figure 4a is in the off position and the switch of Figure 4b is in a momentary off position; Figures 5a, 5b and 5c are plan, side and front views of a single switch in accordance with the present invention with the switch in the off position;

Figure 6 is a cutaway view of the single switch of Figures 5a, 5b and 5c; and Figure 7 is a perspective cutaway view of the single switch of Figures 5a, 5b and 5c.

A first embodiment is now described in the form of a twin switch 100. Figures 1a, 1 b and 1 c show plan, side and front views of the twin switch 100 and Figure 2 shows a perspective view of the same twin switch 100. The twin switch 100 has a body 102 providing a housing including a top surface 158 in which two switch members 104,106 are disposed. The switch members 104,106 pivot about a hub at a pivot point 110.

The twin switch 100 has a base member 112 which locates the electrical terminals 114a, 114b, 116a, 116b, 118a, 118b. In this embodiment, the terminals 114a, 116a, 118a are operated by switch member 106 and terminals 114b, 116b and 118b are operated by switch member 104. The base member 112 has a longitudinal flange 122 which extends from the base of the twin switch 100 between the terminals of the two switch members 104,106. The base member 112 also has a lateral flange 120 which extends from the base of the twin switch 100 between terminals 114a, 114b and terminals 116a, 116b. An optional further lateral flange could be provided between terminals 116a, 116b and terminals 118a, 118b.

The base member 112 is attached to the body member 102 by a snap fit.

Projections 130 extend from the base member 112 and are received in openings 128 in the body member 102.

The body member 102 has a generally cubic shape with the top surface 158 opposite to the base member 112. The body member 102 has openings 132,134 to allow the ingress and egress of liquid and water vapour though the body member 102. The openings 132,134 have intermittent supports 136 to maintain the rigidity of the body member 102 shape. Liquid and vapour can also enter the

body member 102 through the top surface 158 where it surrounds the switch members 104,106. Any water will drain through the openings 132,134 in the body member 102.

The body member 102 has arms 124 extending outwardly from the front and back of the cubic shape of the body member 102. The arms 124 are attached to the body member 102 at the base of the body member 102 and are sprung such that the free ends of the arms 124 extend outward as they progress towards the top surface 158 of the body member 102. The arms 124 have grip portions 126 on the outside surfaces of the free ends of the arms 124. The arms 124 are depressed when the twin switch 100 is inserted into a housing in a wall of an appliance and the grip portions 126 ensure that the twin switch 100 is gripped within the housing.

In this embodiment, lights 108 are provided on the switch members 104,106 to provide an indication of whether each switch 104,106 is on or off. The lights 108 have a clear plastic window which may be coloured red for clarity and ease of viewing.

Referring now to Figure 3, the inside of the twin switch 100 described above is shown. It can be seen that the body member 102 has an outer portion 160 which generally houses the components of the twin switch 100. The body member 102 also has an inner portion 162 which extends in a manner parallel to the sides of the outer portion 160 within the body member 102. The inner portion 162 provides sides for an inner cavity 164 within the body member 102.

The switch member 104 has a top portion 166 and side portions 168 which sit within the top surface 158 of the body member 102. The switch member 104 has an inner member 138 which has a close stepped attachment to the side portions 168 of the switch member 104. The inner member 138 projects between the inner portion 162 and the outer portion 160 of the body member 102. A lip 170 of the end of the inner member 138 furthest from the switch member 104 has a close, watertight communication with the outside of the inner portion 162 of the body

member 102 or the inside of the outer portion 160 of the body member 102 dependent on the position of the switch member 104.

The inner member 138 of the switch member 104 houses the components of the light 108. The inner member 138 38 also has a central portion 144 which extends into the switch body 102. Opposite the end of the central portion 144 a moving contact 142 is provided. The moving contact 142 is attached to terminal 116a and can move between a position in which no electrical contact is made and a position as shown in Figure 3 in which electrical contact is made with terminal 114a. A contact pad 154 on one end of the moving contact 142 connects with a contact pad 156 on the terminal 114a. Terminal 118a extends upwardly within the body member 102 and contacts a contact pad 172 embedded in the inner member 138 of the switch member 104 when the switch is in the on position as shown.

The body portion 102 allows water, water vapour or other liquids to pass through it through openings 132,134 whilst maintaining an internal cavity 164 which is watertight. The internal cavity 164 is formed of the base member 112, the inner portions 162 of the body member 102 and the inner member 138 of the switch member 104. The internal cavity 164 contains the electrical contacts and therefore the safety requirements are met.

Figures 4a and 4b show part sections of a second embodiment of a switch. Figure 4a shows the switch in an off position. Figure 4a shows a main spring 146 which extends between the central portion 144 of the inner member 138 of the switch member 104 and the moving contact 142. A contact spring 148 is also provided between the terminal 118a and the contact pad 172.

Figure 4b shows the switch in a momentary off position and shows a bias spring 150 between the base member 102 and the switch member 104. There is also shown a platform rocker 152.

A third embodiment is now described in the form of a single pole switch 200. The reference numerals used in this embodiment have the same last two digits for

features corresponding to features already described in relation to the twin switch 100.

A single pole switch 200 is provided with a body member 202 of an elongated cubic form. Figures 5a, 5b and 5c show the single pole switch 200. The single pole switch has three terminals 214,216 and 218. A base member 212 encloses the base of the single pole switch 200 and positions the terminals 214,216 and 218. Two lateral flanges 220,222 project from the base member 212 and extend between the terminals 214 and 216 and the terminals 216 and 218.

A switch member 204 of the single pole switch 200 is housed in the top of the body member 202 and the switch member 204 has a hub with provides a pivot point 210 in a corresponding hole in the body member.

The body member 202 has arms 224 which are spring biased and extend outwardly from the body member 202. The arms have grip portions 226 at their free ends. The arms 224 hold the body member 202 of the single pole switch 200 in a housing in an appliance wall.

The base member 212 has a snap fit connection to the body member 202. The body member 202 has openings 228 adjacent the base member 212 into which projections 230 from the base member 212 snap fit.

The body member 202 has openings 232,234 to allow the ingress and egress of liquid and vapour into the outer body of the single pole switch 200. The openings 232,234 have intermittent supports 236 to maintain the rigidity of the body member 202.

Figure 6 and Figure 7 show cutaway portions of the single pole switch 200 in an off position. It can be seen that the body member 202 has an outer portion 260 which generally houses the components of the single pole switch 200. The body member 202 also has an inner portion 262 which extends in a manner parallel to

the sides of the outer portion 260 within the body member 202. The inner portion 262 provides sides for an inner cavity 264 within the body member 202.

The switch member 204 has a top portion 266 and side portions 268 which sit within top of the body member 202. The switch member 204 has an inner member 238 which has a close stepped attachment to the side portions 268 of the switch member 204. The inner member 238 projects between the inner portion 262 and the outer portion 260 of the body member 202. A lip 270 of the end of the inner member 238 furthest from the switch member 204 has a close, watertight communication with the outside of the inner portion 262 of the body member 202 or the inside of the outer portion 260 of the body member 202 dependent on the position of the switch member 204.

The inner member 238 has a central portion 244 which extends into the switch body 202. Opposite the end of the central portion 244 a moving contact 242 is provided. The moving contact 242 is attached to terminal 216 and can move between a position in which no electrical contact is made as shown in Figures 6 and 7 and a position in which electrical contact is made with terminal 214. A contact pad 254 on one end of the moving contact 242 connects with a contact pad 256 on the terminal 214. Terminal 218 extends upwardly within the body member 202 and contacts a contact pad 272 embedded in the inner member 238 of the switch member 204 when the switch is in the on position as shown.

The body portion 202 allows water, water vapour or other liquids to pass through it whilst maintaining an internal cavity 264 which is water proof. The internal cavity 264 is formed of the base member 212, the inner portions 262 of the body member 202 and the inner member 238 of the switch member 204. The internal cavity 264 contains the electrical contacts and therefore the safety requirements are met.

Improvements and modifications can be made to the foregoing without departing from the scope of the present invention.

Claims

1. An electrical switch comprising the components of a body member, a switch member and a base member, the components providing inner and outer compartments, wherein the inner compartment is watertight and houses the electrical contacts of the switch and the outer compartment has openings for ingress and egress of fluid.

2. An electrical switch as claimed in claim 1, wherein the base member locates a plurality of terminals of the switch.

3. An electrical switch as claimed in claim 1 or claim 2, wherein the base member has a watertight snap fit attachment to the body.

4. An electrical switch as claimed in any one of claims 1 to 3, wherein the switch is a twin rocker switch.

5. An electrical switch as claimed in any one of claims 1 to 3, wherein the switch is a single pole rocker switch.

6. An electrical switch as claimed in any one of the preceding claims, wherein the switch includes an illumination means for indicating the position of the switch.

7. An electrical switch as claimed in any one of the preceding claims, wherein the body member has spring biased locating arms for locating the body of the switch in a cavity

8. An electrical switch substantially as hereinbefore described with reference to Figures 1 to 4.

9. An electrical switch substantially as hereinbefore described with reference to Figures 5 to 7.