US 2823278 A
Description (OCR text may contain errors)
Feb. 11, 1958 M. c. CARLSON ET AL PUSH BUTTON ADAPTER SWITCH Original Filed April 15, 1955 5% Z fi j i y United States Patent PUSH BUTTON ADAPTER SWITCH i Marvin C. Carlson and Clarence H. Brown, Valparaiso,
Ind., as'signors to McGill 'Manufacturing Company, Valparaiso, Ind., a corporation of Indiana Continuation of application Serial No. 349,028, April 15, 1953. This application February 25, 1957, Serial No. 642,299
6 Claims- (Cl. 200-65) The present invention relates to electrical switching devices, and more particularly to an improved electrical switch of such rugged construction that it maybe sub- .jectedto abusive use without impairing its operating ef- 'ificiency.
"example, with vacuum cleaners and the like are usually 1 operated by foot so that it is necessary thatsuch switches be not only convenient to operate in this manner but be capable of withstanding excessive and sometimes abusive use.
In the past, toggle switches have been used for vacuum cleaners or the like and have operated with some measure of satisfaction. It has been found, however, that toggle switches are rather 'difficult and awkward to operate con- "veniently'by the'use rs foot. Because of the inadequacies -of the toggle switches, plunger-type switches have been 'used for foot-operations, but it has proved diflicult' to provide apush button switch that is capable of withstanding over long intervals of time the abuse to which foot-operated switchesare often exposed.
It is an object of the-present invention to provide an 'improved electrical switch of the plunger type which 'is husky' and rugged in its construction so as torender' it ideally suited for footoperation in vacuum cleaners 01 the like. 7
A further object of the invention is to provide such an "improved electrical switch which, although it exhibits rugged' features for foot operation, incorporates a relatively fragile and inexpensive; switching element so that the switch may be constructed cheaply.
Another object of the invention is to provide such an improved electrical switch which, in addition to its rugged characteristics, issmall and compact so that it may be 1 conveniently-used in applications where space is'at' a premium.
A further object of the invention is to providesuch "an improved electrical switching device which may be assembled in a simple and expeditious manner and which 'may be conveniently adapted to the electrical circuit in which it isused.
Still a further object of the invention isto provide such an improved electrical switching'device' that is capable of performing its switching function efiiciently despite' the force and speed at which itis actuated.
A feature of the'invention -is the provision of an im proved ele'ctr'ic'alswitching device of the plunger-type that performs its switching operation on the return stroke ofthe plunger sothatthe aforementioned relatively delicate "switching element 'itselfis not subject to damage during the downstroke' of the-plunger by the foot of the user.
Another *feature of the 'invention'is the provision 'of --an -improvedelectrical switching device of the plunger 2,823,278 Patented Feb. 11, 1958 "ice gether with further objects and advantages thereof, may
best be understood by reference to the following description when taken in conjunction with the accompanying drawing in which:
Fig. 1 showsthe foot-operated switching device of the invention mounted, as an illustrative example, in avacuurn cleaner; and
Fig; 2 shows the switching device of the invention, slightly modified as compared with the embodiment of Fig. 1, withvv the top section of the casing removed to expose the operating components of the switch.
The improved electrical switching device of the invention comprises a housing and a switching element rotatably mounted in the housing,.0r casing, and havinga plurality of peripheral teeth with a plurality of interconnected electrical contact faces respectively disposed on alternate ones of ,the teeth. Av pair of resilient-stationary contacts.are supported withinflthefhousing and contact oppositely disposed teeth on the. switching element to be bridged electrically by pairs of theaforementioned contact faces when the switching element ,is in alternate angular positions. A ratchet wheel is mounted coaxially with the switching element. and is integral'therewith. A plunger is supported in an external neck portion formed integrally with the housing, and the plunger is movable within the neck along an axis perpendicular to .the axis of rotation of the switching element and ratchet. A coil spring is mounted in a reduced section ofthe plungerand baises the plunger away fromvthe aforesaid axis of rotation. Finally, a pawl and guideare secured. to onecnd of the plunger and extend awayfromltheplunger in spaced parallel relation to straddle .the. ratchet. In this manner, the depressionof the plunger-against the coil spring cocks the pawl over the ratchet and release .of the plunger causes the coil spring .tomove the plunge-r away from the aforementioned axis of rotation so that zthetpawl rotates the ratchet and switchingelement fromone angular position to another.
As previously stated, Fig. lshows a .vacuum cleaner 10 having a switch 11 constructed inaccordance withthe invention supported at one end thereof.
Switch 11 includes a plunger element 12 which.may;beconveniently operated by the foot of the useralternatelytqplace the vacuum cleaner in and out of operation. ,In the switch of Fig. l, the power cord 13 is connecteddirectly to the operating elements of .the switch. The switching device of Fig. 2 is similar to that of Fig. l with the exception that it includes a pair of prongs 14,15 .whichpmay-be plugged into a suitable receptacle on power cord 13 so that the switching device may conveniently be:connected into the electrical circuit of the vacuum cleaner.
The switch of 'Fig.'.2 includes. a casingoruhousing 16 which maybe of molded insulating material andisin two sections, the top section being removed, to reveal thevarious components of the switch. The casing sectionsare held together normally by a pair of metallic rivets 17 18 extending through the two sections. The switch in Fig.
2 is shown double its actual size for purposes of clarity,
and it can be seen that the switch is extremely small in size rendering'it suitable for applicationsin'which space is limited.
essence Casing 16 has an external neck portion 19 formed intcgral therewith and surrounding an aperture 20 in the casing, the aperture having a reduced diameter With respect to the diameter of the neck portion. Plunger 12 is mounted in the neck portion and has a stem 21 of reduced diameter which extends through aperture 20. A retaining plate 22 is provided adjacent aperture 20 and has an opening therein through which the end of stem 21 extends. Retainer 22 is supported in casing 16 by a pair of legs or posts which extend into apertures in both casing sections.
A coil spring 23 is mounted around stem 21 and bears against a shoulder formed between plunger 12 and stem 21 and also against retaining plate 22, and the spring normally biases the plunger outwardly from the interior of the casing.
A resilient metallic guide 24 and a resilient metallic pawl 25 are formed from a single metallic strip which is bent over so that the guide and pawl are in spaced parallel relation. The upper portion of the aforementioned strip has a key-way formed therein which engages a slot at the end of stem 21, so that the guide and pawl are supported on the stern by spring 23 which causes the stem to draw the end of the strip against retaining plate 22. The guide and pawl extend away from the stem toward the interior of the casing as shown.
The switching device also includes a rotatable switch member 26 of molded insulating material which has integral trunnions journalled in apertures in the casing sections. The switch member includes a large toothed wheel 27 of molded insulating material provided with alternately deep and shallow peripheral teeth. The shallow teeth have electrical contact faces 28 disposed thereon, and the contact faces are all interconnected by a metallic spider 29.
Adjacent wheel 27 and coaxial therewith there is provided an integral ratchet wheel 31) of molded insulating material having peripheral teeth corresponding in number to the teeth in the larger wheel 27. The guide and pawl 24, 25 straddle ratchet wheel so, and pawl 25 is provided with a lateral projection 25a which engages behind the teeth of the ratchet wheel to rotate the ratchet wheel from one angular position to the next whenever coil spring 23 drives plunger 12 away from the axis of rotation of wheel 27 and ratchet 311.
With the construction described above, depression of plunger 12 against the bias of coil spring 23 moves pawl 25 and guide 24 inwardly over ratchet wheel 3 to cock the pawl, and the removal of pressure from plunger 12 causes spring 23 to move the plunger outwardly and the projection 25a of pawl 25 to rotate ratchet wheel 36 and therefore wheel 26 from one angular position to the next. The inward force of plunger 12 is received wholly by casing 16 since the shoulder between the plunger and stem 21 is driven against the side of the casing adjacent aperture 20. This inward motion has no effect on the relatively fragile switching mechanism within the casing since it merely cocks the pawl and guide over the ratchet, the switching mechanism being engaged by the pawl only on the return stroke of the plunger. For this reason, any degree of force may be exerted on plunger 12 and, so long as the casing is capable of withstanding such force, the switch is not damaged thereby. Moreover, the aforementioned force may be applied with any range of speed without impairing the functioning of the switch since in each instance the switching element is operated only by the relatively slow spring biased return motion of the plunger.
Prongs 14 and are supported within casing 16 by integral posts 31 and 32,32a which extend into apertures in the two casing sections. Prong 14 is connected to a resilient stationary contact 3.3, whereas prong 15 is connected to a terminal 34 which may be of the screw type and which is accessible from the exterior of casing 16. A further screw type terminal 35, also accessible from outside the casing, is provided in the switch which is supported on a pair of posts 36, 36a which also extends into apertures in the casing sections. A further resilient contact 37 is mounted on posts 36, 36a. Resilient contacts 33 and 37 are bent so as to have inwardly curved contacting portions lying opposite each other and engaging opposite ones of the aforementioned peripheral teeth on the rotatable switch wheel 27. The contacts 33, 37 each have a substantially straight portion which is rebent upon itself to give additional resilience. At the end of the rebent portions, the contacts are bent at a right angle and secured to the espective posts 31, 36.
As the switch element 26 is rotated by the action of plunger 12, resilient contacts 33, 37 pass from a pair of peripheral teeth on wheel 27 having contact faces 28 thereon, to a pair having no contact face. In this manner, an electrical connection is alternately made and broken between resilient contacts 33, 37 for successive angular positions of switch member 26 upon actuation of plunger 12.
As previously noted, prongs 14 and 15 may be conveniently inserted in a receptacle in power cord 13, and electrical terminals 34 and 35 are connected to the leads from electric motor of the vacuum cleaner. Prong 15 makes a direct connection with electrical terminal 34, whereas prong 14 makes a connection with terminal 35 that is made and broken by actuation of the switching device in the previously described manner.
Although the invention has been described in conjunction with a vacuum cleaner, it is apparent that the improved switch disclosed herein is ideally suited for any application in which a rugged and compact switch is required. The switch is adapted to take any kind of initial operating power applied within a wide range of speed, and such power merely stores up a suflicient amount of energy ultimately and immediately thereafter to operate the switch. That stored-up energy is always the same because it is represented by coil spring 23 having been moved a uniform distance and which causes the switch element to be operated uniformly at all times, such operation occurring only during the return motion of the plunger and irrespective of the initial application of power or the speed at which it is applied. Therefore the switching mechanism itself can be relatively fragile and inexpensive because the initial force is all taken by the switch mounting.
While a particular embodiment of the invention has been shown and described, modifications may be made and it is intended in the appended claims to cover all such modifications as fall within the true spirit and scope of the invention;
1. A switch device including in combination a housing having side walls and an end wall with a housing aperture of selected diameter therein, a toothed wheel rotatably mounted between said side walls and having alternately conducting and insulating teeth thereon, oppositely mounted fixed resilient contact means simultaneously engageable with teeth of the same type on said wheel, a ratchet wheel coaxially positioned and rotatable with said toothed wheel and adapted to be revolved to cause rotation of said toothed wheel for alternately completing and opening a circuit between said fixed contact means and through said switch device, an external neck flange portion of selected width formed around said housing aperture and having an internal opening communicating with said housing aperture and of a diameter greater than the diameter of said housing aperture to form a restricted housing portion at the juncture of said internal opening and said housing aperture, a plunger longer than said selected width and reciprocally disposed in said internal opening in said'neck flange portion, said plunger including a stem extending therefrom into said housing and having a slot adjacent the end thereof within said housing,
. a retaining plate disposed between said side walls and lel arms disposed on opposite sides of said ratchet wheel and a cross-portion'joiriing'said spaced arms'having a keyway therein fitted into said slot of'said stem so that said spring biases said cross Qrtion into engagement with said retaining'plate, whereby'p'ressing movementof said plunger by an operator toward said restricted'housing portion moves Isaid pawl'i'rieriiber against said spring and the release of said plungerby the operator causes said spring to move said pawl member across said ratchet wheel,said pawl'memb'er'having' a portion engageable behind a' tooth of said ratchet'wheel 'as the s'ai'nerrioves thereacross to cause revolution of the same and operation of the switch device.
2. In a switch device having a mechanism including a rotatably mounted toothed wheel with alternately conducting and insulating teeth thereon, oppositely mounted fixed resilient contact means simultaneously engageable with teeth of the same type on said wheel, and a ratchet wheel coaxially positioned and rotatable with said toothed wheel and adapted to be revolved to cause rotation of said toothed wheel for alternately completing and opening a circuit between said fixed contact means and through said switch device, the combination of a molded housing having side walls and an end wall with a housing aperture therein, an external neck flange around said housing aperture on the outside of the housing, said neck flange having a cup-shaped cavity therein communicating with said housing aperture which is of a diameter less than the diameter of .said cup-shaped cavity to form a restricted housing portion at the juncture of said cavity and said housing aperture, an actuating plunger longer than the depth of said cavity and reciprocally disposed in said neck flange portion to be operated by the foot or hand of an operator, said plunger including a stem extending therefrom into said housing and having a slot adjacent the end thereof within said housing, a retaining plate dis posed between the housing side walls within the housing and having a retainer aperture therein in alignment with said housing aperture and through which said stem extends, a coil spring surrounding said stem and in compressive relation between said retaining plate and said plunger, with said spring biasing said plunger relative to said retaining plate, and a pawl member for operating said ratchet wheel and fitted to said slot in said stem, whereby pressing movement of said plunger toward said restricted housing portion of said housing moves said pawl member and compresses said spring, and release of said plunger by the operator causes said spring to move said pawl member across the ratchet wheel, said pawl member having a portion engageable behind a tooth of said ratchet wheel as the same moves thereacross to cause revolution of the same and operation of the switch device.
37 A switch device including in combination a walled housing with a housing aperture bore of a selected diameter in one wall thereof, switch mechanism within the housing including fixed contact means and means movable therebetween for operating a circuit between said fixed cont act means and through said switch mechanism, an external neck flange portion around said housing aperture bore and externally thereof to form a cavity of selected depth and having an internal opening communicating with said housing aperture bore, the inside diameter of said cavity being greater than the inside diameter of said housing aperture bore, a plunger longer than the selected depth of the cavity and reciprocally disposed in said internal opening in said neck flange portion, said plunger including a stem extending therefrom into said housing and mechanically connecting with the movable means of the switch mechanism within said housing means for said plunger to maintain it against withdrawal from said neck- 6 flange portion cavity, a retaining plate disposed within said h'ou'sing -and having a retainer aperture therein in *alignment with said' housing aperture bore and through which sa'id s'te'm extends, a coil spring surrounding said 'stemin' aposition between said retaining plate andsaid 'Plim'gerfwith pressing movement of said plu-nger by an operator towardsaid housing'a'perture acting to move said-spring to compress the same and the release of said plunger by the operator acting to cause said spring 'to move'said plunger and the movable switch "means'therewith'to' cause-a change in the circuit through said switch mechanism, and me'ans outwardly'of thehousing and electrically connected to the switch mechanism to act ona circuit 'which isoutwardlyof the switch device.
4. In an electric switch device'having a switch mechanism including movably mounted means for effecting electrical switching and a pair of stationary contact prongs extending laterally from said movably mounted means, and being electrically connected therewith so that connection can be made to the switch device through such contact prongs, the combination of a molded walled housing having a housing aperture in one wall thereof, an external neck flange around said housing aperture on the outside of the housing, said neck flange defining a cup-shaped cavity therein communicating with said housing aperture and of an internal diameter greater than the diameter of the housing aperture, an actuating plunger longer than the depth of said cavity and reciprocally disposed in said cavity and neck flange portion to be operated by the foot or hand of an operator, said plunger including a stern portion extending therefrom into said housing and operatively connected with said movably mounted means, means maintained by said housing having an aperture therein in alignment with said housing aperture and through which said stem portion extends, a coil spring surrounding said stem portion which is in compressive relation between said maintained means and said plunger, with said coil spring biasing said plunger relative to said maintained means, whereby a pressing movement of said plunger toward said housing aperture moves said movably mounted means in the switch mechanism to efiect a first switching operation and compresses said spring, and the release of said plunger by the operator causes said spring to move said plunger outwardly and move the movably mounted means to effect a second switching operation of the switch device.
5. An electric switch device including in combination a molded structure comprising a main Walled housing portion and a walled cavity portion extending laterally from one wall of said main walled housing portion and integral with said main housing portion, said walled cavity portion comprising an annular flange defining a cavity centrally thereof, said main walled housing being hollow in the center thereof and having an opening extending from such hollow to such cavity, with the diameter of said opening being less than the internal diameter of said cavity to form a shoulder in said cavity surrounding said opening, switch mechanism within the main walled housing portion including movable means for circuit making and breaking by the switch device, a plunger having a head portion longer than the depth of the cavity and disposed for guided in-and-out movement therein and having a stem portion extending through said opening and into the hollow of the main walled housing portion, with said stem portion being operatively connected with said switch mechanism movable means, spring means on the stem portion of the plunger in compressible position relative to the plunger head portion, with a pressing movement of said plunger by an operator causing movement of said switch mechanism movable means and compressing said spring and the release of said plunger by the operator causing said spring to move said plunger outwardly and to move said switch mechanism movable means, and means supported by the main walled housing for making electric circuit connections on the outside of the switch device to go through said switch mechanism.
6. In an electric switch device as defined in claim 5, wherein the means for making electric circuit connections on the outside of the switch device comprises a terminal member outwardly exposed at a wall of the main walled housing portion opposite the wall of the switch device from which the plunger extends, and a pair of male member contact prongs and a second terminal member, with said pair of contact prongs extending through and outwardly from a wall of the main housing portion and said second terminal member being exposed at another wall of the main housing portion, said latter two named walls being oppositely disposed with respect to one another and being between the first wall named herein and the wall from which the plunger extends.
References Cited in the file of this patent UNITED STATES PATENTS Broadman Dec. 22, 1896 Goddard July 7, 1925 Popp Sept. 18, 1934 Thorp et a1 "June 13, 1939 Johnson Mar. 14, 1944 Popp July 31, 1951 Rasini Feb. 12, 1952 FOREIGN PATENTS Germany Apr. 26, 1923 France Apr. 26, 1946