Four function electrical rocker switch

This application is a continuation-in-part of application for U.S. Letters patent Ser. No. 08/865,921 filed May 30, 1997, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention deals with electrical switches, and more particularly, with multiple function electrical switches that can be placed in a single, standard gang box.

2. Description of the Prior Art

As the use of electrical equipment in the home and commercial establishments increases, there is a need to increase the number of electrical switches used for controlling or supplying electrical power to such equipment. However, much of this equipment is placed in existing structures where it is difficult to increase the number of gang boxes in which such switches can be placed or increase the number of electrical cables extending through existing walls. To provide adequate heat dissipation and to insure that all equipment is properly connected to a neutral return conductor, the number of switch devices or receptacles in each box is limited and each cable that provides electrical power to such switches and receptacles must also contain the neutral return conductor.

At present, triple rocker switches are available, each providing a single pole, single throw on-off switch and requiring two conductors for each switch unit. Thus, there are six conductors crowded into a single gang box which increases the possibility of physical contact between individual conductors or between the conductors and the gang box which may result in short-circuits. Also, the heat produced by these closely placed conductors may exceed safe levels.

One approach that reduces the crowding in the gang box and reduces the number of conductors for the switches is shown in U.S. Pat. No. 5,384,441 issued Jan. 24, 1995 and assigned to the assignee of the instant invention and by this reference incorporated into the instant application, makes use of a common phase conductor for each of the three rocker switches. Thus, the number of electrical conductors used in a gang box including such a switch arrangement is reduced to four. The number of rocker switch units, however, remains at three.

SUMMARY OF THE INVENTION

The instant invention overcomes one of the problems presented by the prior art by permitting the substitution of a single pole, double throw, center-off switch for one of the single pole, single throw on and off switches. The use of a common phase line for the two single pole, single throw switches permits these two switches to be wired using the three conductors of common three conductor cable and insures that the neutral return conductor is present in the cable to which the switches are wired.

The single pole, double throw, center-off switch can also be wired to the same three conductors used for the two single-pole, single throw switches. Thus, using the same three conductor cable, the number of switches has been increased to four. It is an object of this invention to provide a novel four function electrical rocker switch.

It is an object of this invention to provide a novel four function electrical rocker switch which can be placed within a single gang box.

It is an object of this invention to provide a novel four function electrical rocker switch which can be placed within a single gang box and wired to a single three conductor cable.

It is still another object of this invention to provide a novel four function electrical switch having two on/off single pole, single throw switches and a single pole, double throw, center-off switch.

Other objects and features of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principles of the invention, and the best mode which is presently contemplated for carrying them out.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings in which similar elements are given similar reference characters:

FIG. 1

is a front perspective view of a four function electrical rocker switch constructed in accordance with the concepts of the invention.

FIG. 2

is a side elevational view of the switch of FIG.

1

.

FIG. 3

is a perspective view of the mounting strap of the switch of FIG.

1

.

FIG. 4

is a bottom plan view of the switch of FIG.

1

.

FIG. 5

is a top plan view of the inside of the base housing of the switch of FIG.

1

.

FIG. 6

is a rear elevational view, partially in section, taken along the line

6

—

6

of FIG.

5

.

FIG. 7

is a fragmentary, side elevational view, partially in section, taken along the line

7

—

7

in FIG.

5

.

FIG. 8

is a top plan view of the movable contact member of the switch of FIG.

1

.

FIG. 9

is a side view of the movable contact member of FIG.

8

.

FIG. 10

is a side elevational view of the movable contact member of

FIG. 9

taken along the line

10

—

10

.

FIG. 11

is a top plan view of a fixed contact member of the switch of FIG.

1

.

FIG. 12

is a side elevational view of the fixed contact member of FIG.

11

.

FIG. 13

is a bottom plan view of the cover of the switch of FIG.

1

.

FIG. 14

is a side elevational view of the rocker of the single pole, single throw switch sections of the switch of FIG.

1

.

FIG. 15

is a side elevational view of the spring employed with the rocker of FIG.

14

.

FIG. 16

is a top plan view of the spring of FIG.

15

.

FIG. 17

is a top plan view of the fixed contact member of the rocker of the single pole, double throw switch portion.

FIG. 18

is a side elevational view of the fixed contact member of FIG.

17

.

FIG. 19

is a front elevational view of the fixed contact member of

FIG. 17

with the contact removed.

FIG. 20

is a perspective view of a cradle for the movable arms and contacts of the single pole, double throw center-off switch portion.

FIG. 21

is a front elevational view of the movable arms and contacts of the single pole, double throw center-off switch portion.

FIG. 22

is a front elevational view, partially in section, of the movable arms and contacts of

FIG. 21

mounted in the cradle of FIG.

20

.

FIG. 23

is a side elevational view of the rocker of the single pole, double throw center-off switch portion of the switch of FIG.

1

.

FIG. 24

is a front elevational view, in section, of the rocker of the single pole, double throw center-off switch portion.

FIG. 25

is a side elevational view, partially in section, of the rocker assembly and contacts of the rocker of the single pole, double throw center-off switch portion in a closed position.

FIG. 26

is a fragmentary top plan view of the wiring of the single pole, double throw center-off switch portion.

FIG. 27

is a schematic diagram of the four function electrical rocker switch of FIG.

1

.

FIG. 28

is a top plan view of the movable arms and contacts of the single pole, double throw center off switch portion.

FIG. 29

is a top plan view of a modification of the instant device showing two single pole, double throw, center off switch sections.

FIG. 30

is a schematic diagram of the five function rocker switch of FIG.

29

.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning now to

FIGS. 1

,

2

,

3

and

4

, there is shown the exterior of a four function electrical rocker switch

50

constructed in accordance with the concepts of the invention. A base

52

, as will be described below, contains the various fixed and movable contacts and the operating means therefore. Fixed to the base

52

is a cover

54

which contains three apertures

56

,

58

and

60

(see

FIG. 13

) through which project three rockers

62

,

64

and

66

, respectively. A strap

68

surrounds the cover

54

and assembles it to the base

52

and provides for mounting the switch

50

to the mounting ears of a gang box (not shown) as is well known in the art. Strap

68

has flat portions

70

at each end through which extend apertures

72

to receive mounting screws

74

to fasten switch

50

to the ears of a gang box (not shown). Threaded apertures

76

accept the threaded fasteners of a cover plate (not shown) to finish the installation of the switch

50

to a gang box. Squares of insulation

78

on fasteners

74

insulate the strap

68

from the ears of the gang box.

Tabs

80

extend from each of the flat portions

70

at right angles to such flat portions

70

and are bifurcated at their free ends

82

. The tabs

80

extend between two raised ribs

84

on the end walls

86

of base

52

and within inturned ends

88

of raised ribs

84

(see FIG.

5

). The two legs

83

of the tab free ends

82

are separated and peened over the bottom edges of ribs

84

to assemble the strap

68

to base

52

.

The bottom

90

wall of base

52

has a series of openings

92

,

94

,

96

,

98

,

100

and

102

to receive the bared ends of individual insulated conductors (not shown). Slots

104

,

106

and

108

are adjacent the openings

92

,

94

and

96

, respectively, to permit the release of the conductors in the openings adjacent the slots when a small flat tool blade is inserted into a slot, as will be described in more detail below.

Referring now to

FIGS. 5

to

16

, there is shown the details of the rocker switch sections operated by rockers

64

and

66

. These rocker switch sections are more fully described in the aforementioned U.S. Pat. No. 5,384,441 issued Jan. 24, 1995. Rocker

66

has an upper curved surface

110

terminating at ends

112

and

114

, respectively. To place the rocker

66

in one of its two stable rest positions, the upper surface

110

is depressed at either of the ends

112

and

114

. Recesses

116

receive therein pivot pins

118

formed on the cover

54

walls which define the recesses

56

,

58

and

60

(see FIG.

13

). Extending from the bottom surface

120

of rocker

66

(see

FIG. 14

) is toggling arm

122

whose free end

124

contains a slot

126

to receive the straight portion

128

of toggle spring

130

(see

FIGS. 15 and 16

) whose other end

132

is placed about hub

136

(see

FIG. 6

) on the inside surface

134

of bottom

90

wall. Two spring stops

138

flank hub

136

and limit the travel of the toggle spring

130

and thus of the rocker

66

itself. Two spring rests

140

also flank hub

136

, off-set from the spring stops

138

by 90° (see FIG.

5

). The spring rests

140

support the free end

132

of toggle spring

130

above the inside surface

134

so that the toggle spring

130

is free to move between its two stable positions. An actuating arm

142

also extends from bottom surface

120

of rocker

66

to a free end

144

which engages the brush arm

148

of brush assembly

146

, fabricated from spring stock (see

FIGS. 8

,

9

and

10

). Brush arm

148

extends from brush backplate

156

to a free end at which is placed a movable contact

150

. Contact

150

is made of a silver alloy or similar material having good conductive properties and may be installed adjacent the end of brush arm

148

by welding, brazing, crimping or the like. As shown in

FIG. 10

, brush arm

148

has an initial position at about 30° up from a plane perpendicular to brush backplate

156

. As will be described below, this position prevents contact between movable contact

150

and its associated fixed contact except when the free end

144

of its associated actuating arm

142

engages it.

A contact arm

164

is formed with a contact surface

166

from brush backplate

156

and bent 90° with respect to the plane of the brush backplate

156

as at

168

. The end of brush backplate

156

forms a clamp wall

158

which ends in two retainer sections

160

and

162

, forming a chevron. The bared end of a conductor (not shown) is inserted through opening

92

and is positioned on contact surface

166

and held there by retainer sections

160

and

162

. This connects the entire brush backplate

156

to the same point and by that means connects to both movable contacts

150

and

154

. Thus, only a single conductor is required for both movable contacts

150

and

154

and the circuits which they form or open when rockers

64

and

66

are operated.

The fixed contacts are arranged upon fixed terminal assemblies, such as

170

made of resilient spring stock. There must be a separate fixed terminal assembly for each circuit that the rockers

64

and

66

form or open. The fixed terminal assemblies

170

each have a fixed terminal backplate

180

on which are formed a contact support arm

172

to which is attached, by welding, brazing, crimping or the like, a fixed contact

174

made of a silver alloy or other highly conductive metal. A contact arm

176

is partially severed from backplate

180

and bent 90° with respect to the plane of backplate

180

as at

188

.

The contact arm

176

terminates in a contact surface

178

. The clamp wall

182

is formed with retainers

184

and

186

joined to form a chevron. When a solid conductor is inserted through openings

94

or

96

the bared end of the conductor generally engages the contact surface

178

and the apex between retainers

184

and

186

and is held there by the resilience of the fixed terminal assembly

170

.

As more fully set forth in the '441 patent, when rocker

66

is positioned as it is in FIG.

1

and end

112

is depressed and end

114

is above the cover

54

, the actuating arm

142

is not in contact with brush arm

152

and the natural resilience and the angle at which brush arm

152

is set permits movable contact

154

to remain out of engagement with a fixed contact

174

of fixed terminal assembly

170

. Toggle spring

130

rests on the right spring stop

138

. By depressing rocker

66

at end

114

, the rocker

66

begins to pivot in a clockwise direction about its pivot pins

118

(see

FIG. 13

) and toggle spring

130

is compressed. Once the end

114

goes below its mid-point, the toggle spring

130

expands and takes a position against left spring stop

138

to define the second stable position of rocker

66

. The actuating arm

142

engages brush arm

152

and closes movable contact

154

to fixed contact

174

completing the circuit.

Despite the fact that both brush arms

148

and

152

are connected to a common source, the rockers

64

and

66

can be operated separately so that both circuits, controlled by brush arms

148

and

152

, can be closed or on, both open or off or one on and one off. As shown in

FIG. 27

, rockers

66

and

64

are in their off positions and brush arms

152

and

148

are in their open positions preventing the flow of current from the phase line to the loads

1

and

2

to the neutral line.

Turning now to

FIGS. 4

,

5

, and

17

to

27

, there is shown the single pole, double throw rocker center-off switch operated by rocker

62

. As shown in

FIG. 5

, the chamber

190

, in which rocker

62

is located, does not have on inside surface

134

of bottom wall

90

a hub

136

, spring stops

138

or spring rests

140

. Instead it has a raised central portion

192

whose flat top portion

194

is generally surrounded by a raised wall

196

interrupted as at

198

. An aperture

200

extends through flat top portion

194

. A saddle

202

(see

FIG. 20

) having a base

204

equal in area to the bounded flat top portion

194

of raised central portion

192

has an aperture

206

aligned with aperture

200

to receive therein a rivet

208

(see

FIG. 26

) to fix saddle

202

to flat top portion

194

of raised central portion

192

. Saddle

202

has two side walls

210

extending from two parallel marginal edges of and perpendicular to base

204

. A tab

212

extends from the rear intermediate edge in the plane of the base

204

. The bared end of a conductor

214

introduced through opening

102

in bottom wall

90

is soldered, welded or braised to tab

212

. The side walls

210

each have slots

216

therein to define two fingers

218

,

220

.

Chamber

190

also has two sets of fixed contact supports

222

and

222

′ each made up of two C-shaped ribs extending upwardly from the inner surface

134

of bottom wall

90

and facing one another to receive the shoulders

232

of the fixed contact back plate

226

. Cleats

234

permit the backplate

226

to be positioned in the C-shaped ribs but not removed once they are in place. The fixed contact support arm

228

extends between the C-shaped ribs and supports the fixed contact

230

adjacent fixed contact support

222

. The bared end of a conductor

236

extends through opening

98

and is soldered, welded or braised to the back surface of the fixed contact back plate

226

. In a similar manner fixed contact back plate

226

′ is positioned in the C-shaped fixed contact supports

222

′ and fixed by its cleats

234

. The fixed contact support arm

228

′ extends between the C-shaped ribs of fixed contact supports

222

′ and supports the fixed contact

230

′. The bared end of a conductor

238

extends through opening

100

and is soldered, welded or brazed to the back surface of the fixed contact back plate

226

′. To produce a five function switching device a second chamber

190

is employed as shown in FIG.

29

. Its schematic drawing is shown in FIG.

30

.

Referring now to

FIGS. 21

,

22

and

28

, the make-up and mounting of toggle contact

240

is described. Toggle contact

240

is fabricated from a single length of stiff metal and is formed in a single punching and forming step to provide rigid arms

242

and

244

. The arms

242

and

244

are slightly narrower than the slots

216

and can move within such slots

216

. Adjacent the center of contact

240

is an enlargement

246

which is wider than the slots

216

and which can engage the fingers

218

and

220

. The length of the enlargement

246

along the contact

240

is less than the spacing between side walls

210

and thus the contact

240

can move to a limited degree within saddle

202

. When the plunger, to be described below, rests above the enlargement

246

, the rocker

62

is in a static central position with ends

112

and

114

equally above the surface of cover

54

. This is an off position for rocker

62

and is identified as the center-off position. Fastened to the free end of arm

242

is movable contact

248

and a contact

250

is fastened to the free end of arm

244

. The contacts

248

and

250

are made of a silver alloy or other highly conductive metal and may be attached by welding, brazing, crimping or the like. In the center-off position movable contact

248

does not engage fixed contact

230

and movable contact

250

does not engage fixed contact

230

′.

The toggle contact

240

is placed in the saddle

202

with enlargement

246

generally centered between side walls

210

with each of the arms

242

,

244

extending through a separate one of the slots

216

between fingers

218

,

220

. The arms

242

,

244

are free to move within their associated slots

216

. As shown in

FIG. 28

, the enlargement

246

is wider than the slots

216

and thus enlargement

246

acts to limit movement of toggle contact

240

in saddle

202

as well as limit movement of the enlargement

246

in saddle

202

. The saddle

202

is connected to one line of an AC power source (not shown) by means of a conductor

214

fastened to tab

212

making the entire saddle

202

electrically hot.

Rocker

62

is shown in

FIGS. 23

,

24

and

25

. Rocker

62

is different than rockers

64

and

66

and employs a spring loaded plunger which serves to fix the two stable rest positions of the toggle contact

240

and moves the arms

242

and

244

to close the movable contacts

248

,

250

and associated fixed contacts

230

,

230

′, respectively. Rocker

62

has a curved top surface

110

with ends

112

and

114

and two recesses

116

to receive the pivot pins

118

of cover

54

. A hollow sleeve

252

extends downwardly as shown in FIG.

24

. The cylindrical portion

256

of plunger

254

is positioned in and free to move within sleeve

252

. A first bore

258

in plunger cylindrical portion

256

communicates with a second bore

260

of a greater diameter to provide a shoulder

262

where bores

258

and

260

meet. A compression spring

264

extends between shoulder

262

and the interior wall

63

of rocker

62

to urge the plunger

254

out of sleeve

252

. Plunger

254

has a tapered free end

266

which engages the arms

242

,

244

to close the movable contacts

248

,

250

to the fixed contacts

230

,

230

′, respectively. The tapered free end

266

is so dimensioned that it can travel along substantially the entire length of arms

242

and

244

and within slots

216

between fingers

218

,

220

. The plunger

254

cannot be ejected from sleeve

252

because the recesses

116

engage the pivot pins

118

to prevent rocker

62

from coming out of aperture

56

at the top and the engagement of the tapered free end

266

of the plunger

254

with the toggle contact

240

prevents ejection of plunger

254

from sleeve

252

.

Assuming that rocker

62

is initially in the center-off position, that is with ends

112

,

114

at the same distance above cover

54

and the cylindrical portion

256

of plunger

254

is over the enlargement

246

, movable contacts

248

and

250

are both spaced from their associated fixed contacts

230

,

230

′ and both possible circuits are open. Depressing rocker

62

at end

112

causes rocker

62

to pivot in a counter-clockwise direction about pivot pins

118

. The cylindrical portion

256

of plunger

254

exits through slot

216

of saddle

202

between fingers

218

,

220

and along arm

244

. The toggle contact

240

shifts its position so that movable contact

250

on arm

244

pivots about the base of slot

216

and engages the fixed contact

230

′. The enlargement

246

shifts position to engage the inner surfaces of the fingers

218

,

220

of the left sidewall

210

. Movement of the toggle contact

240

causes the movable contact

250

to wipe the surface of fixed contact

230

′ and remove dirt, oxides and other contaminants. Since the toggle contact

240

is rigid the movement of movable contact

250

to engage fixed contact

230

′ causes the arm

242

to pivot in a counterclockwise direction, as shown in

FIG. 25

, and further separate movable contact

248

from fixed contact

230

. Movement of rocker

62

continues until a stop

268

is engaged by the rocker

62

. At this point a solid contact exists between movable contact

250

and fixed contact

230

′. The rocker

62

can be engaged at end

114

and moved to the center-off position or to the second closed position between movable contact

248

and fixed contact

230

. Stop

270

controls clockwise pivoting of rocker

62

.

FIG. 27

shows the operation of rocker

62

, as described above, in schematic form. Toggle contact

240

is shown in its center-off position and can be moved to engage fixed contact

230

to close the path from the phase line through load

3

to the neutral line or engage fixed contact

230

′ to close the path from the phase line through load

4

to the neutral line. Thus, using the three rockers

62

,

64

and

66

the path to both loads

1

and

2

can be closed and one of the paths to loads

3

and

4

can be closed.

Although a switching device is shown with one or two single pole, single throw switches and one or two single pole, double throw, center-off switches, any combination of single pole, single throw switches and single pole, double throw, center-off switches may be employed.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to the preferred embodiments as are presently contemplated for carrying them out, it will be understood that various omissions and substitutions and changes of the form and details of the device illustrated and in its operation may be made by those skilled in the art, without depending from the spirit of the invention.