US 3083278 A
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Description (OCR text may contain errors)
March 26, 1963 R. A. MuKAl 3,083,278
March 26, 1963 R. A. MuKAl FooT 0x PALM AcTUAToR SWITCH Filed July 2 Sheets-Sheet 2 United States Patent O 3,083,278 FOT OR PALM ACTUATR SWITCH Roy A. Mukai, Milwaukee, Wis., assignor to Cutler- Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Filed Juiy 27, 1960, Ser. No. 45,589 9 Claims. (Cl. 200-865) This invention relates to electric switches and particularly to a sealed electric switch for foot or palm actuation.
Foot or palm actuated switches are often used in applications in lwhich high reliability is required. To this end it is desirable that the switch be easy to actuate and have as few, and as simple, parts as necessary in order to minimize Operating difiiculties. It is further desirable to provide a dust tight switch so that the Operating mechanism will not be hampered 'by dust accumulating in the housing.
One object of this invention is to provide a foot or palm switch having an enlarged button also serving as a cover for the switch housing with such cover button being mounted in the housing to prevent canting and sticking.
Another object is to mount the switch mechanism in the housing so that actuation of the cover button relieves pressure on the swtich mechanism 'so that even a sharp blow on such button cannot damage the switch mechanism.
Still another object is to provide means lfor sealing the above-described switch.
The first object is accomplished by providing a button having a short skirt portion projecting inside the switch housing and guiding such skirt by nylon cylinders spaced around the inside periphery of such housing. The cover button is connected to a plate suspended inside the housing which actuates the switch mechanism and such plate is guided at its center by a guide boss projecting upward from the bottom of the housing. Guiding the plate at its center prevents the plate and button assernbly from canting in the housing.
The second object is accomplished by mounting a snap acting switch with its actuator above the button-actuated plate so that downward Operating pressure on the cover button moves the plate away from such actuator and cannot act to overload the snap switch mechanism.
The third object is accomplished by constructing the cover button with a portion extending substantially in Vertical alignment with the housing exterior and cutting a groove in such portion and in the adjacent housing exterior to receive the edges of an expansible rubber sealing member. By positioning the housing and cover button grooves as described a symmetrically shaped sealing member can be used and a good seal obtained when the cover button moves with respect to the housing. An overhanging lip is further provided on the cover button to protect the sealing member.
Other objects and advantages will be pointed out in, or be apparent from, the specification and claims, as will obvious modifications of this invention shown in the drawings, in which:
FIGURE 1 is a side sectional view of the switch;
FIG. 2 is an exploded perspective view of the switch; and
FIG. 3 is a bottom view of the cover button.
Referring to the drawings, a switch housing has internally threaded inlet 9 and outlet 11 openings through which leads may pass and into which pipe conduits may be screwed. One of these openings may be plugged and all connections made through the other opening if desired. Switch housing 10 is provided with shoulders '12 projecting from opposite sides thereof adjacent the bottom 3,083',278 Patented Mar. 26, 1963 ICC and with an upwardly extending boss 14 located centrally on the bottom of the housing. A circular depression 13 in the housing bottom encircles boss 1-4 and is sized to receive a coil spring having a function described below.
An enlarged cover button 16 closes the open end of the housing and has a short skirt portion v18 which extends inside the housing. Eight nylon cylinders 23 are spaced around the inside periphery of the housing for cooperation with skirt 18V to guide movement of the button in the housing and to keep sliding friction to a minimum. A plate 26 is suspended inside the housing (for actuation of a switch contained therein) by means of a cross bar 30 connected to the cover 'and spacer bars 28 which connect the crossbar to the plate. Cross piece 30 fits into a groove 33 molded into the bottom of the cover buttonto prevent rotation of the cross piece with respect to the cover. Screw 32 conuects the cover button to the cross piece and such screw is fixed to the underside of a plate 34. An O-ring 36 is captured between plate 34 and the top of the button to seal the screw hole in the button. Purchase of plate 34 for screwing it tightly against the O-ring is provided by slot 35. Plate 34 may have a legend inscribed thereon to ndicate the control function of the switch las well as acting as a pressure sealing plate as described. The cover button, cross piece, spacers, and plate are all one assembly and tend to cant in the housing if guided only by the nylon cylinders which bear on the skirt of the cover button. This problem is overcome by providing plate 26 with a centrally located downwardly opening .sleeve 25 'which fits over and is guided by a boss 14 projecting upwardly from the bottom of the housing. Boss 14 has a nylon sleeve 15` fitted around it to provide a low friction guide for sleeve 25. By providing this central guide point for the cover button assembly in conjunction with the nylon bearing cylinders, the canting or window looking tendency of such assembly is reduced to the point where it is of no consequence.
Button 16 also has an overhanging portion 19 which overlaps the switch housing and includes a circular groove 17 lying above and in superposition with a groove 21 on the eXterior of the housing. These grooves provide a mounting for flexible diaphragm member 22 which has enlarged round edges 20 which resiliently snap into such grooves. Because of the position of these mounting grooves an inexpensive annular sealing diaphragm may be used and such diaphragm snaps into the grooves very easily. Cover button overhang portion *19 curves over and downward along the diaphragm to protect it from wear.
Actuation of the cover button cannot possibly overload the switch -rnechanism inside the housing because such actuation moves the actuating plate 26 away from the switch actuator button 45, thereby relieving, not increasing, pressure on the switch button. This is accomplished by supporting the cover button assembly by a coil spring 24 which encircles boss 14 and rests on the housing bottom and by mounting -a snap-acting switch 44 above the actuating plate 26 which forms part of the spring supported cover button assembly.
Plate 26 has notches 23 in opposite sides and a bracket 40, which is secured to housing shoulder 12 by screws 27, fits in each of these notches to prevent the actuating plate, and hence the cover button assembly, from rotating within the housing. Each bracket also has a portion 42 overlying the top of the spring plate so that the plate, and hence the cover button, are prevented from being withdrawn from the housing. Therefore, brackets 42, 40' each serve to prevent rotation of the actuator assembly in the housing and also hold such assembly in the housing. Snap acting switch 44 extends between the brackets and is secured to the brackets by screws 47. Plate 26 is biased against the switch actuator button 45 by the support spring 24 to hold button `415 in its depressed switch actuating position.
The description above contemplates the use of only one snap acting switch; however, two such :switches may be used with only minor changes in the present construction. Additional holes 50 are required in the brackets and the housing shoulders, and an insulator is placed between the pair of snap acting switches which are secured to the brackets. The switch mechanisms are insulated from each other by the switch casings but the insulator is necessary toprevent arcing or actual contact between the leads connected to the terminals. The clearance between the switch terminals and spacer bars is reduced to an unsafe distance when two lswitches are used so that insulative sleeves are mounted over the spacers for protective purposes. Cutouts 46 in the skirt of the cover are also required when two switches are used to provide sufficient electrical spacing between the switch termin-als and the conductive skirt.
The present invention is to be limited only by the scope of the following claims.
1. A foot or palm actuated switch comprising, a housing having an open end, a cover button reciprocably mounted in the open end of said housing, at least one switch mechanisrn suspended in said housing and having an actuator facing away from said open end, Operating means extending from said cover button and positioned to engage said actuator as said cover button moves outwardly of said opening, and holding means in said housing cooperating with said operating means to keep said cover button properly positioned in said housing and to prevent rotation of said cover button with respect to said housing.
2. The switch according to claim 1 in which said cover button includes a skirt extending inside said housing, said housing having first guide means onthe inside periphery for guiding said skirt, said Operating means including an actuating plate suspended in said housing below said switch actuator and having a guided member centrally located thereon, and second `guide means fixed to the bottom of said housing for cooperation with said guided member whereby said first and second guide means prevent canting and binding of said cover button and said Operating means in said housing.
3. The switch according to claim` 2 in which said first guide means comprises a plurality of low friction material cylinders secured to the inside periphery of said housing 'and projecting inwar'dly beyond the surface thereof, said guided member being a sleeve secured to said plate, and said second yguide means lbeing a boss having a low frictionouter surface projecting into said sleeve.
4. The switch according to claim 1 in which said cover button includes a portion overhanging the exterior surface of said housing, said overhanging portion and said housing exterior each having a circular groove therein with such grooves being spaced and superimposed one above the other, and an annular resilient sealing member having one edge mounted in one groove and another edge mounted in the other groove.
5. The switch according to clairn 4 in which said overha'nging cover button portion extends over and at least partly around said member to protect said sealing member.
6. The switch according to claim 1 in which said switch mechanism is fixed with respect to said housing and said Operating means includes a plate fixed with respect to said cover button, and biasng means normally urging said plate upward against said switch actuator.
7. The switch according to claim 6 in which said plate has at least one notch in an edge thereof, said holding means including a bracket connected to said housing and projecting into said notch in said plate and overlapping the side of said plate nearest the open end of said housing whereby said bracket limits axial movement of said plate toward the open end of said housing and prevents said plate and cover button from rotating with respect to said housing.
8. A foot or palm operated switch comprising a housing having an open end, a cover button closing the open end' of said housing .and having a portion projecting inside said housing, at least one spacer member fixed With respect to said cover button, a plate suspended by said spacer inside said housing in spaced relation to the bottom of said housing, a spring between said plate and said housing bottom, a bracket fixed to said housing and overlapping said plate to provide a stop against which said spring normally biases said plate, said plate having a notch in an edge into which a portion of said bracket projects to prevent rotaton of said plate and cover button with respect to said housing, at least one switch mechanism mounted on said bracket, said switch mechanism including an actuator positioned for actuation by said plate when said plate is based to its normal position, guide means located on the bottom of said housing, guided means at the center of said plate cooperating with said guide means, a plurality of low friction 'bearing members projecting from the inside periphery of said housing for Cooperation with said actuator button, said guide means and bearing members serving to determine the reciprocable path of said cover button and plate.
9. The switch according to claim 8 in which said cover button includes a portion overhanging the exterior surface of said housing, said overhanging portion and said housing exterior each having a circular groove therein with such grooves being spaced and superimposed one above the other, and an annular resilient sealing mern'ber having one edge mounted in one groove and another edge mounted in the other groove.
References Cited in the file of this patent UNITED STATES PATENTS 2346,149 Brewer Apr. 11, 1944 2,357,973 Robbins Sept. 12, 1944 2,669,616 Frank Feb. 161, 1954 2,773,955 Haydon et al Dec. 11, 1956 FOREIGN PATENTS 855,676 Great Britain Dec. 7, 1960