US3618409A

US3618409A - Safety switch

Info

Publication number: US3618409A
Application number: US862368A
Authority: US
Inventors: Ralph W Shifley
Original assignee: Emerson Electric Co
Current assignee: Emerson Electric Co
Priority date: 1969-09-30
Filing date: 1969-09-30
Publication date: 1971-11-09
Anticipated expiration: 1988-11-09

Abstract

IN A STANDARD ROCKER TYPE "ON-OFF" SWITCH, A SWITCH LEVER IS PROVIDED WHICH IS ASYMMETRICAL WITH RESPECT TO THE PIVOT AXIS, WITH AN ACCESSIBLE PROJECTION IN THE DIRECTION OF THE "OFF" POSITION GREATER THAN IN THE DIRECTION OF THE "ON" POSITION WITH RESPECT TO THE PIVOT AXIS, SO THAT THE SWITCH IS MOST READILY MOVED TO THE "ON" POSITION BY GRASPING SIDES AND LIFTING UP OF THE PROJECTION OF THE LEVER IN THE "OFF" DIRECTION, A RELATIVELY DIFFICULT MANIPULATION, AND IS READILY MOVED TO THE "OFF" POSITION BY PRESSURE AGAINST THE LEVER.

Description

Nov. 9, 1971 R, w. SHN-LEY 3,618,409

SAFETY SWITCH Filed Sept. 30, 1969 nazi/96 United States Patent O 3,618,409 SAFETY SWITCH Ralph W. Shilley, Normandy, Mo., assignor t Emerson Electric Co., St. Louis, Mo. Filed Sept. 30, 1969, Ser. No. 862,368 Int. Cl. F16h 21/54 U.S. Cl. 74-102 j 7 Claims ABSTRACT 0F THE DISCLOSURE In a standard rocker type on-off switch, a switch lever is provided which is asymmetrical with respect to the pivot axis,with an accessible projection in the direction of the od position greater than in the direction of the on position with respect to the pivot axis, so that the switch is most readily moved to the on position by grasping sides and lifting up of the projetcion of the lever in the off direction, a relatively difficult manpulation, and is readily moved to the off position by pressure against the lever.

BACKGROUND OF THE INVENTION In conventional rocker switches of the type used on radial saws, bench saws, drill presses and the like, an off-on lever is provided which is symmetrical with respect to the pivot axis in its accessible areas, and is moved to the on and oli positions with equal effort. The shape of the lever is such as to make it necessary as a practical matter to turn the switch to either position with ones thumb or finger.

One of the objects of this invention is to provide a switch which is easy to turn off and relatively difficult to turn on.

Other objects will become apparent to those skilled in the art in the light of the following description and accompanying drawings.

SUMMARY OF THE INVENTION In accordance with this invention, generally stated, in an on-01T switch wherein a manually operated switch lever is pivoted on an axis for rocking or rotating movement between on and off position, a switch lever is provided which is asymmetrical with respect to the pivot axis, with an accessible projection in the direction of the off position greater than in the direction of the on position with respect to the pivot axis.

The invention has particular application to a rocker switch with a rectangular housing on which a lever is mounted for rocking movement between two mounting brackets which normally define the limits of acccsibility of the lever. In the switch of this invention, the on end of the lever slopes to an edge inboard of a mounting bracket while the olf setcion of the lever projects over the other bracket in the off position and is arranged to clear a hole inthe monuting bracket in the on position.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawing, FIG. l is a view in side elevaiton, with interior parts shown in dotted lines, of one illustrative embodiment of the sketch of this invention; and

FIG. 2 is a sectional view taken along the line 2-2 of FIG. l.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing for one illustraitve embodiment of safety switch of this invention, reference numeral 1 indicates a completed switch, having a rec- ICC tangular housing 2, a pivot frame 3, mounted on the housing 2, a pivot pin 4 mounted on the frame 3, and an on-off lever 5 rockably mounted on pivot pin 4.

The housing 2 has a long narrow bottom wall 21, two broad side walls 22, two short narrow end walls 23 and a long narrow open mouth 24 defined by a planar edge 25. Terminal ears 26, projecting from the bottom wall 21, form part of electrical components 27 which, while essential elements of the electric switch, form no part of this invention. The housing 2 and its contents are in all respects conventional.

The pivot frame 3 is also conventional. It is symmetrical with respect to the housing and is made of a one piece stamping which includes mounting clamps 31 crimped under shoulders provided on the housing; a pair of iiange members 32 embracing the upper edge of the long side walls; two mounting brackets 33, with a riser part 34 projecting substantially parallel to and beyond the end walls 23, and a ledge part 35 with a hole in it to receive a mounting screw, and two pivot plates 36.

The pivot pin 4 is mounted centrally, between the two mounting brackets 33. The pin 4 has a head 41 at each end. Both the frame 3 and the pin 4 are conventional.

The lever 5 is constructed conventionally in the area between the pivot pin 4 and the bottom of the casing, and includes a groved semi-circular body 51, boses 52, integral with the body, and spring loaded plungers 53, which serve to actuate the electrical elements of the switch. Integral with the body portion 51 beyond the outer edge of the pivot plates 36, the lever is formed with a sloped on section 55, which, in the embodiment shown, is curved on a radius with the pivot axis, and an off section 56. The off section 56 has a part 57 projecting, in the off position as shown in solid lines in FIG. l, over the bracket ledge 35.

In the embodiment shown, both the on and off sections of the lever have a top surface 60 of substantial width, and two side surfaces 61. An end surface 62 at the ofi end of the lever, slopes from the top surface of the olf section part at a re-entrant angle toward the housing. As shown particularly in FIG. l, in the off position of the lever, the end surface 62 projects from the outer edge of the ledge 35 sufficiently to provide a lifting surface so that the lever can be moved to on position if the bracket ledge 35 is liush with ab road surface by manually pushing up on the end surface 62. The angle of the end surface 62, however, is so related to the throw of the switch as to clear the mounting hole in ledge 35 when the lever is in the on position, as indicated in broken lines in FIG. l.

In the embodiment shown, an end edge 65 at the on end of the lever surfaces has a stop shoulder 66, abbutting an upper surface of the frame 3 when the switch is in the on position.

It can be seen that, because of the slope of the lever surface in the on section of the lever, it is very difficult to rock the lever to the on position merely by presing the lever on the on side of the pivot. It is easier to grasp the side of the lever on the off side or to push on the surface 62. On the other hand, it is very easy to rock the lever from on to off position by pushing on the top surface 60 of the projecting section of the lever on the off side. Thus, the swithc can be rocked to the off position by brushing it with ones knee or elbow, or almost any other part of the body, if his hands are occupied.

Numerous variations in the construction of the switch of this invention, within the scope of the appended claims, will occur to those skilled in the art in the light of the foregoing disclosure. Merely by way of example, the

sloped surface of the on section of the lever might be made planar instead of arcuate, as long as the slope is such as to inhibit turning the switch on by pressing on that section. This is merely illustrative.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. In an onoi switch having a switch housing and a manually operated switch lever pivotally mounted on said housing for rocking movement between on and off positions, the improvement comprising a switch lever asymmetrical with respect to the axis on which 1t is pivoted, said switch lever having a top surface including an off section on one side of said pivot axis and an on section on the other side of said pivot axis, exposed to manipulation through a reach from said off section to said on section, said off section having greater accessible projection than said on section with respect to the pivot axis, said ofi section moving away from said housing in moving from off to on position and toward said housing in moving from on to off position, and said pivot axis lying between the top surface of the off section and the housing, whereby said switch is turned off more easily than it is turned on.

2. The improvement of claim 1 wherein the part of the lever on the off side of the pivot axis has graspable side surfaces, whereby the lever can be pulled to rock it to on position.

3. In a rocker switch of the type having a rectangular housing with a long narrow bottom wall, two broad side walls, two short narrow end walls and a long narrow open mouth defined by a planar edge, in which an operating lever is mounted for rocking movement between an off position toward one end wall and and on position toward the other end wall on a pivot pin mounted centrally with respect to the narrow end walls on said housing across and spaced outwardly from the mouth of said housing and two mounting brackets on said housing, one at each short narrow end wall of the housing, having a riser part extending beyond the mouth of the housing and defining lateral limits of accessibility for manipulation of said lever, said bracket having ledge parts projecting in a direction outboard from the housing and each having a hole therein for the reception of mounting means, the improvement comprising said levers having a top surface, two side surfaces and at least one end surface, a convexly rounded section between a plane including the axis of the pivot pin and perpendicular to the plane of the edge deiining the open mouth of the housing and a part of the lever adjacent the one of the brackets on the on end wall of the housing, said lever part being inboard of and within the outermost reach of the said bracket when the lever is in on position and said lever having a second section between said plane and the other of said brackets, said second section projecting toward and over the ledge of the said other bracket, said section having an end surface sloped from the top surface of said section at a reentrant angle toward the housing whereby when the lever is in its on position, the said end surface is inboard of the mounting means receiving hole in the ledge of the bracket, and is farther from the said ledge than it is in its off position.

4. The improvement of claim 3 wherein the distance from the axis to the top surface on the off side of the plane through the axis is greater than the distance from the axis to the top surface at every point on the on side of the plane through the axis in both on and oif positions of the lever.

5. In an onoff switch having a switch housing and a manually operated switch lever pivotally mounted on said housing for rocking movement between on and off positions, the improvement comprising a switch lever asymmetrical with respect to the axis on which it is pivoted, said switch lever having a top surface including an off section on one side of said pivot axis and an on section on the other side of said pivot axis, exposed to manipulation through a reach from said off section to said on section, said off section having greater accessible projection than said on section with respect to the pivot axis, said off section moving away from said housing in moving from off to on position and toward said housing in moving from on to off position, and said pivot axis lying between the top surface of the off section and the housing, whereby said switch is turned off more easily than it is turned on, said on section `being sloped from the area of the axis toward the housing to inhibit moving the switch to on position by pressing on the said part.

6. In an onotf switch having a switch housing and a manually operated switch lever pivotally mounted on said housing for rocking movement between on and off positions, the improvement comprising a switch lever asymmetrical with respect to the axis on which it is pivoted, said switch lever having a top surface including an off section on one side of said pivot axis and an on section on the other side of said pivot axis, exposed to manipulation through a reach from said off section to said on section, said off section having greater accessible projection than said on section with respect to the pivot axis, said off section moving away from said housing in moving from off to on position and to ward said housing in moving from on to off posltlon, and said pivot axis lying between the top surface of the off section and the housing, whereby said switch is turned off more easily than it is turned on, said off section having a reentrant end surface of sufficient extent to permit its being pushed by human finger from oi to on position.

7. In an onotf switch having a switch housing and a manually operated switch lever pivotally mounted on said housing for rocking movement between on and off positions, the improvement comprising a switch lever asymmetrical with respect to the axis on which it is pivoted, said switch lever having a top surface includlng an 01T section on one side of said pivot axis and an on section on the other side of said pivot axis, exposed to manipulation through a reach from said off section to said on section, said off section having greater accessible projection than said on section with respect to the pivot axis, said off section moving away from sald housing in moving from olf to on posltlon and toward said housing in moving from on to off position, and said pivot axis lying between the top surface of the 01T section and the housing, whereby said switch is turned off more easily than it is turned on, said on section of the pivot axis being sloped from the area of the axis toward the switch on a radius with the pivot axis to inhibit moving the switch to on position by pressing upon the said part.

References Cited UNITED STATES PATENTS 2,789,170 4/1957 Johnson 200-172 3,081,390 3/1963 Lasar 200--172 3,217,112 11/1965 Campbell et al. 200-172 FOREIGN PATENTS 1,155,358 6/1969 Great Britain ZOO-153.10

WILLIAM F. ODEA, Primary `Examiner W. S. RATLIFF, IR., Assistant Examiner U.S. Cl. X.R. 200-172