US3819894A - Rotary switch with linear plunger and helical motion transferring means - Google Patents

Abstract

An electric switch particularly useful on an appliance such as a refrigerator, freezer, oven or the like, for controlling internal illumination is provided. The switch may be a door frame mounted device. Internal components convert a telescoping thrust drive, initiated by closure of the door, for example, into rotational movement of one of the telescopic components. The rotating component drives a stepped contact rotationally so as to make or break an electric circuit or path between the terminal contacts of the switch. The interval terminal contacts of the switch are contact pads and the rotational movement of the stepped contact makes wiping or scrubbing contact with the contact pads thereby cleaning the contact surfaces of the contact pads when physical and electrical contact is made.

Description

United States Patent [191 Flumignan et a1.

[73] Assignee: Gulf & Western Industries, Inc.,

New York, NY.

[22] Filed: Mar. 7, 1973 [21] Appl. No.: 338,861

[52] U.S. Cl. 200/156, 200/159 R [51] Int. Cl. H011! 19/14, I-lOlh 3/12 [58] Field of Search ZOO/61.81, 61.82, 156,

[56] References Cited UNITED STATES PATENTS 3/1965 Loesch 200/159 R 2/1972 FOREIGN PATENTS OR APPLICATIONS 765,556 Great Britain 200/156 Anthony 200/156 June 25, 1974 Primary ExaminerJames R. Scott Assistant Examiner-Gerald P. Tolin Attorney, Agent, or FirmKenneth E. Merklen; Thomas E. Harrison, Jr.; Charles I. Sherman [57] ABSTRACT An electric switch particularly useful on an appliance such as a refrigerator, freezer, oven or the like, for controlling internal illumination is provided. The switch may be a door frame mounted device. Internal components convert a telescoping thrust drive, initiated by closure of the door, for example, into rotational movement of one of the telescopic components. The rotating component drives a stepped contact rotationally so as to make or break an electric circuit or path between the terminal contacts of the switch. The interval terminal contacts of the switch are contact pads and the rotational movement of the stepped contact makes wiping or scrubbing contact with the contact pads thereby cleaning the contact surfaces of the contact pads when physical and electrical contact is made. i

6 Claims, 13 Drawing Figures PATENTEDJUNZSIQM 3319.894

I saw 1 or 4 FIG. 3

(D LO mimcnmz lw 3.819.694

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FIG. 7

PATENTEDJUNZS 1914 SHEET 3 [1F 4 ROTARY SWITCH WITH LINEAR PLUNGER AND HELICAL MOTION TRANSFERRING MEANS The present invention relates to electric switch devices used for on/off switching of electric currents and- /or voltages normally used to drive household and other appliances. in particular, the present invention relates to remote/manual type switches adapted for use as a door actuatable switch such as used on a refrigerator, freezer or other appliances, having an interior lamp for interior illumination, for example, where it is desirable to effect electric switching, such as turn on an interior lamp on the inside of the appliance when one opens the door of the appliance and to turn ofi the same lamp when the door of the appliance is closed.

Switches used for such utility are normally exposed to large amounts of moisture and wide ranges of temperature and, heretofore, for the most part have used contacts of precious and semi-precious metals since these metals more favorably resist corrosion usually caused by the presence of metal in an environment where both the moisture and temperature vary over wide ranges. Corrosion of metal contacts in a switch for use in an electric circuit usually effects the reliability of the switch and most often contributes to early failure of the switch.

The present invention is an electric switch that has successfully been usedon appliances such as refrigerators and freezers as a door actuated switch and has been exposed to wide ranges of moisture and temperature change. The present switch avoids the use of precious and/or semi-precious metals in its contacts and has served reliably without failure due to corrosion.

For convenience and simplicity the switches here discussed shall be referred to in general as appliance-door actuated switches or A/D switches, although by using such terminology limitation of the use and character of the switch is not intended, and the term A/D switch is meant to include all switches of the general type discussed herein.

The normal characteristic of the A/D switch is to provide a breakable or openable electric circuit of which the switch itself is a part, the electric path having at least two electric terminals, one for coupling with the electric driven component, an electric lamp, for example, and the other terminal for coupling to electric power. Another lead from the other electric power output is coupled to the driven'component, in normal fashion to complete the electric circuit. In some forms of an A/D switch, (a two-terminal type), the electric path formed by the switch elements, is isolated in the switch itself while in other forms, (a single-terminal type) the electric path formed by the switch elements, is integrated into the body of the A/D switch. This latter'form usually includes only one insulated terminal with a switching element, the body forming the other terminal. This latter type A/D switch may often be found used in devices which use the body or chasis of the appliance as a current path, or ground path for the electric circuit. An automobile is one example of a device which uses the body or chasis of the vehicle as an electric ground path. The former type A/D switch may often be found used in refrigerators, freezers, ovens and the like, for example.

Prior A/D switches have employed colliding or meeting physical contact between metal contacts of the switch with pressure applied by some biasing force. In

the case of prior A/D switches, used in a refrigerator, for example, the actuating force is nonnally movement of the refrigerator door. The A/D switch would function to open an electric light circuit when the door is closed, the closed door holding pressure on the A/D switch and thus keeping the interior light of the refrigerator turned off. When the door of the refrigerator is opened the A/D switch is effectively released and the A/D switch functions to close the electric light circuit so that the light is illuminated when the door is open. Closure of the electric switch, thereby completing the electric light circuit, is effected by a biasing force. In order to insure clean contact and good electric contact the conductor material used in the contacts is either precious metal or semi-precious metal. Precious and semi-precious metal resists corrosion and provides good electric connection with relatively light contact force.

The present invention provides a novel A/D switch having substantially different construction which provides substantially different physical contact between the internal switching components of the switch. The switch includes a plunger which responds to external driving pressure and recesses into the body of the switch. Upon application of such pressure, internal components of the switch telescope into each other and convert such telescoping thrust into rotational movement of one of the telescoping components. Upon relief of such pressure a biasing force provides a driving force which telescopes the same internal components out of each other while the plunger exists from the body of the switch. This expanding telescoping drive is converted into rotational movement of the same component in a direction opposite to the rotational movement created by the telescoping thrust. The rotational movement of the telescoping component drives a stepped wiper contact rotationally so as to make or break an electric circuit or path between spaced terminals of the switch. Movement on, or contact between the wiper contact and the spaced terminals may be described as a scrubbing movement or contact or a wiping movement or contact between the rotationally driven wiper contact and the contact pads of the spaced or separated terminals. This scrubbing or wiping contact has a dual effect of making good electric contact between the conductor contacts and at the same time, keeping the contacting surfaces clean of corrosion. The contacting action of the novel A/D switch disclosed here is scrubbing or wiping contact which serves to keep contacting surfaces clean and prevent poor electric contact due to accumulation of corrosion and/or dirt on the contacting surfaces of the contact points or areas. Although some corrosion of the metal contacts may occur, the contacts are scrubbed or wiped clean by the scrubbing or wiping contact action and good electric connection is maintained. The use of the scrubbing or wiping action between electric contacts eliminates the need to use precious and semi-precious metals in the contacts to avoid corrosion. in the A/D switch of the novel construction disclosed herein one driving force used to effect the scrubbing or wiping action and thereby make electric contact between the electric (metal) contacts and clean the metal contacts is the biasing force of the A/D switch. In addition, a, second driving force providing another scrubbing or wiping action for further cleaning the metal contacts is provided when electric contact is in the process of being broken.

This second driving force is a function of the weight of the door and the force with which the door is closed. The scrubbing or wiping of the contacts of the switch is generated by a rotary, slicing action imparted to the moving contact of the switch by converting a straight line driving motion in to a rotary motion.

It is therefore an object of the present invention to provide a novel switch which employs a scrubbing or wiping contact action to provide contact between the electric contacts of the switch.

Another object is to provide a novel switch which employs a wiping action when effecting physical contact between the metal contacts and at the same time cleans the contacting surfaces of the contacts.

Another object is to provide a novel switch which has a driving-wiping action during the process of effecting contact separation which action cleans the contacting surfaces of the switch during the process of separation of the contacts.

Another object of the invention is to provide a switch using a wiping contact action between the metal contact points which avoids the use of precious and/or semi-precious metal contact point.

These and other objects will become apparent when reading the following description of an embodiment of the invention with reference to the accompanying drawings in which:

FIG. I is an exploded view of one embodiment of the novel switch;

FIG. 2 is a side elevation view of the assembled switch;

FIG. 3 is a rear elevation view of the assembled switch;

FIG. 4 is a top elevation view of the assembled switch;

FIG. 5 is another rear view of the assembled switch showing the internal elements comprising the internal electric path;

FIG. 6 is a view of the interior of the cylindrical housing across line 66 of FIG. 1;

FIG. 7 is a sectional view of the cylindrical housing across line 7 -7 of FIG. 6;

FIG. 8 is a view of the end cover;

FIGS. 9 and 10 are cross sectional views' of the end cover shown in FIG. 8 across lines 9 and 10 respectively;

FIG. 11 is a view of a barrel showing the internal tracks;

FIG. 12 is a cross sectional view of the barrel across line 12-12 in FIG. 1 and FIG. 13 is a cross section view of the assembled switch across line 1313 in FIG. 2.

Throughout the various Figures corresponding parts of the disclosed embodiment of the invention will be identified by the corresponding call-out numbers.

Referring to FIG. I, an exploded view of an embodiment of the invention is illustrated as the parts may appear in disassembled form. The A/D switch includes a housing which has a facing 21. The facing 21 is sufliciently large in diameter.to prevent the housing 20 from passing through a retaining hole, made in a wall surface 22 for receiving the housing. Extending from the rear of the facing 21 are positioning studs 23 and 24. The positioning studs 23 and 24 pass through aligning holes in the surface 22 and prevent the housing 20 from rotating in the retaining hole in the surface 22. The housing 20 is tubular or hollow in construction having a shoulder 25 at the facing portion. The housing 20 is preferably made out of non-conductor material, such as plastic, for example. The shoulder 25 of the facing 21 includes opposing nubs 26 and 27 which extend into the hollow section of the housing. These nubs serve to prevent rotation of a floating plunger as discussed below. The nubs are best seen in FIG. 7.

A plunger 30 is provided which rides or floats in a barrel 50 which barrel is supported in the tubular portion of the housing 20. The plunger 30 is of hollow construction being open at one end 31 and closed at the other end 32. On the exterior surface, running along the length of the plunger 30 are two grooves 33 and 34. When the plunger is inserted into the tubular housing 20, via the opening in the shoulder 25, the nubs 26 and 27 ride in the grooves 33 and 34 and prevent rotation of the plunger 30 inside the tubular housing 20. The barrel 50 fits over the plunger 30 so that the plunger 30 floats in the barrel 50.

A spring is inserted in the hollow of the plunger 30, impinging against the interior of the closed end of the plunger and extending beyond the opening 31 and into the barrel 50. The other end of the spring extends into the barrel 50 and impinges against the closed end of the barrel 50. The spring 40 is held in place in the barrel 50 by the spring retaining nub 53. The barrel 50 is seen in FIG. 1, l1, l2 and 13. The exterior of the barrel 50 is seen in FIGS. 1 and 11 with the interior, shown in FIG. 11, (in broken line form) showing the helical racks 51 and 52 and the spring retaining nub 53 along with the contact-wiper retaining pins 54 and 55. A contact-wiper 57 includes on the body thereof a pair of holes 58 and 59 through which the pins 54 and 55 snuggly fit. This structure coupled the contact-wiper 57 to the barrel 50 and provides an easy way of removing the contact-wiper 57 for replacement, if desired. In an alternative structure the wiper-contact 57 could be molded into the closed end of the barrel 50, if desired. As seen, the ends of the wiper contact 57 are stepped to form feet or contact shoes.

The barrel 50, with the contact-wiper 57 on the contact-wiper retaining pins 54 and 55, fits into the opening of the end cover 60 and nests in the end cover, the feet of the wiper-contact 57 making contact with the floor or interval base of the end cover 60. This is clearly seen in FIG. 13.

FIG. 8, in particular, shows an interior view looking into the end cover 60 with the contact-wiper 57 (shown in broken line form) in open switch position. The end cover 60 supports two electrically insulated contact pads 61 and 62. The contact 61 and 62 electrically extend to the bayonnet type terminals 63 and 64 respectively. FIG. 5 shows the contact-wiper 57 and contact pads 61 and 62 (shown in broken line form) in closed circuit position.

In order to hold the end cover 60 aligned with the housing 20 a pair of aligning clips, one on each side of the housing 20, (only one of which, 28, is shown) is provided. The aligning clips extend rom the housing 20 and fit into shoulder sockets of the end cover 60. The exterior of the shoulders sockets and 76 are clearly seen in FIG. 1.

The end cover 60 includes two movable stand- offs 68 and 69 which, when the switch is assembled and in a hole in a wall, extend from the end cover 60 to the inside surface of the wall 22 and prevent crowding or binding of the switch elements due to the trombone or telescopic relation of the components, and the closeness of the components nesting and working in the interior of the end cover. The stand-offs also prevent pressure applied to the back of the end cover 60 from being exerted against the housing and from pushing the housing 20 out of the retaining hole inthe wall 22.

The spring 40 expands between the inside of the closed end 32 of the plunger and the inside of the closed end of the barrel 50, and keeps the barrel 50 positioned against the base of the end cover 60. The spring retaining or positioning nub 53 keeps the spring from wandering about the closed end of the barrel 50.

As the plunger 30 moves in and out of the housing 20, the nubs 26 and 27 ride in the grooves 33 and 34 of the plunger 30 thereby holding the plunger 30 captive, or restraining the plunger 30 from rotational movement, so that the plunger can not rotate in the housing 20. The protuberances 35 and 36 on the plunger ride in the helical tracks 51 and 52 on the inside of the barrel 50. When the plunger 30 telescopes into the hollow of the barrel 50, the barrel 50 is rotated by force exerted by the protuberances 35 and 36 against the shoulders of the helical tracks 51 and 52. As the telescoping occurs the spring is compressed.

The helical tracks 51 and 52 may be helical grooves in the barrel 50 or may be helical slits in the barrel 50 in which the protuberances 35 and 36 on the plunger 30 ride.

In an alternate arrangement the helical tracks may be formed on the plunger 30 and the protuberances may be formed on the barrel 50. The effect of rotating the barrel 50 would still be obtained when the plunger 30 is telescoped into and out of the barrol so long as the plunger is prevented from rotating in the housing 20 as for example, by being restrained from rotational movement by the nubs 26 and 27 riding in the grooves 33 and 34 of the plunger 30.

As the barrel 50 rotates the contact-wiper 57, coupled to the barrel by the retaining pins 54 and 55, is rotated in the direction of rotation of the barrel 50. The feet of the contact-wiper 57 slide arcuately from a contact position on the surface of the contact pads 61 and 62 to a neutral or non-contacting position, off the surface of the contact pads and on to the insulated base of the end cover 60, as seen in FIG. 8. The contactwiper 57 is a conductor of electricity so that when the opposite shoes of the contact wiper are in contact with the contact pads 61 and 62, a circuit is completed between the contact pads 61 and 62 through the feet and body of the wiper-contact 57. The spring 40 is compressed between the closed ends of the plunger 30 and barrel 50 and becomes an increasingly strong biasing force against the oppositely located closed ends of the plunger and barrel. When the plunger 30 is released the compressed spring 40 pushes the plunger 30 out of the barrel 50 and the protuberances 35 and 36 act against the opposite shoulders of the track 51 and 52 and the barrel 50 is forceably rotated in the opposite direction thereby rotating the contact-wiper 57 into contact position with the contact pads 61 and 62, that is, with the feet of the contact-wiper 57 on the surface of the contact pads such as shown in FIG. 5. Thus the internal electric path or circuit in the switch is opened and closed as an in and out telescoping action is converted to a rotational motion.

The end cover 60 includes an annular locking rib 65 which notches into a locking annular groove 65a on the housing 20 for locking the end cover 60 and the housing 20 together.

It was previously noted that the wiper-contact 57 has a shoe at each of its ends. The shoes on the wipercontact 57 serve to limit the contact area between the wiper-contact and the surface of the end cover and contact. pads and to hold the body of the wiper-contact away from the floor or base of the interior of the end cover. The loor or base of the end cover 60 includes two arcuate ramp sections 71 and 72 which effectively raise adjacent sections of the surface of the floor of the end cover to the same level as the surface of the contact pads 61 and 62 respectively, particularly where the shoe of the wiper-contact transverses from the ramp section to the contact pad. The shoes of the wiper-contact 57 stand on the ramp sections 71 and 72 and slide along such ramp section on to, for making contact, and off of, for breaking contact, the contact pads 61 and 62 respectively. To prevent over-ride of the wiper-contact 57, each of the arcuate ramps 71 and 72 rise progressively acuately to form a shoulder at the contact pad with which the respective ramp is not on the same level, that is, as seen in PK]. 8, for example, the surface of the ramp 71, at 71a is at the same level as the surface of the contact pad 61 according a smooth, even surface on which the foot of the wipercontact may slide from the ramp 71 to the contact pad 61. The surface of the ramp 72, at 72b is elevated above the surface of the contact pad 61 to form a shoulder-stop and prevent over-ride of the wipercontact 57. Correspondingly, the surface of ramp 72 at 720 is at the same level as the surface of the contact pad 72 and the surface of the ramp 7] at 71b is elevated above the surface of the contact pad 62 forming a shoulder-stop at 71b. Attention is directed to FIG. 13 which illustrates the contour of the ramp 72. The progressive, arcuate elevation of the ramp 72 is clearly illustrated in FIG. 13 and the surface of the shoulder stop 72b is shown to rise substantially above the surface of the contact pad 61 so as to form a stop for the foot of the wiper-contact when the wiper-contact is on the contact pad 61.

In the preferred embodiment the barrel 50 and the retaining pins 54 and 55 are made of non-conductive material. In addition, the end cover 60, including the arcuate ramps 71 and 72 are also made of nonconductive material. In both cases non-conductive plastic material has been used to form these components in a successfully operating A/D switch. The contact-wiper 57, both the eet and the body, the contact pads 61 and 62 and the connecting terminals 63 and 64 are all made of a formable conductor material. In practice the contact pad 61 and terminal 63 are formed from the same piece of conductor metal. The contact pad 62 and terminal 64 are formed from another piece of conductor metal. This construction can be seen in FIG. 8.

Thus, the structure of a preferred embodiment of the invention has been shown and described with several alternate structures mentioned. In addition the functions and intercooperation of the various components have been described. Although the illustrated form of the invention homes" to a closed circuit condition, that is, when released goes into a closed circuit condition, the structure could easily be modified so that the invention homes to an open circuit condition. To accomplish this modification the position of the contact wiper retaining pins 54 and 55 may be arcuately displaced so that the position of the contact-wiper 57, in a relaxed condition of the switch, would be changed to an open circuit condition. This modification of the structure may require that the arcuate ramps 71 and 72 be repositioned.

Other changes, modifications and/or alterations of the structure of the invention including substitution and/or repositioning of some components may be made, as will be apparent to one skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. An electric switch comprising;

a hollow housing for supporting moving components of said switch,

a barrel floating in the hollow of said housing restrained from moving longitudinally in said housing and removably receiving a plunger,

a plunger, extending into said hollow of said housing,

restrained from moving rotationally, and removably entering said barrel when moving longitudinally relative to said barrel,

bias means for separating said barrel and said plunger,

a helical track on the wall of said barrel and nub means coupled to said plunger and riding in said helical track and rotating said barrel upon longitudinal movement of said plunger relative to said barrel,

an end cover, coupled to said housing, supporting a pair of spaced terminals and limiting longitudinal movement of said barrel in one direction, and contact means coupled to said barrel for alternately completing contact between said spaced terminals when said plunger is in one longitudinal position relative to said barrel and for opening contact be tween said spaced terminals when said plunger is in another longitudinal position relative to said barrel.

2. An electric switch as in claim 1 and in which said contact means coupled to said barrel is contained between said end cover and the bottom of said barrel.

3. An electric switch as in claim 2 and in which said contact means includes a pair of contact shoes on the extremity of said contact means.

4. An electric switch as in claim 3 and in which the hollow interior of said end cover includes a floor and part of said floor includes a ramp around part of the perimeter of said floor and said space terminals are recessed in said floor and are in alignment with said ramp.

5. An electric switch as in claim 4 and in which said ramp in the interior of said end cover includes at least two sections and in which the surface of one section of said ramp is flush with the surface of one of said spaced terminals within the hollow of said end cover and the surface of the other end of said one section of said ramp rises above the surface of the other terminal of said pair of spaced terminals.

6. An electric switch as in claim 5 and in which the shoes of said contact means ride on opposite ramp sections in said end cover and make contact with opposite terminals of said pair of terminals.

Claims (6)

1. An electric switch comprising; a hollow housing for supporting moving components of said switch, a barrel floating in the hollow of said housing restrained from moving longitudinally in said housing and removably receiving a plunger, a plunger, extending into said hollow of said housing, restrained from moving rotationally, and removably entering said barrel when moving longitudinally relative to said barrel, bias means for separating said barrel and said plunger, a helical track on the wall of said barrel and nub means coupled to said plunger and riding in said helical track and rotating said barrel upon longitudinal movement of said plunger relative to said barrel, an end cover, coupled to said housing, supporting a pair of spaced terminals and limiting longitudinal movement of said barrel in one direction, and contact means coupled to said barrel for alternately completing contact between said spaced terminals when said plunger is in one longitudinal position relative to said barrel and for opening contact between said spaced terminals when said plunger is in another longitudinal position relative to said barrel.

2. An electric switch as in claim 1 and in which said contact means coupled to said barrel is contained between said end cover and the bottom of said barrel.

3. An electric switch as in cLaim 2 and in which said contact means includes a pair of contact shoes on the extremity of said contact means.

4. An electric switch as in claim 3 and in which the hollow interior of said end cover includes a floor and part of said floor includes a ramp around part of the perimeter of said floor and said space terminals are recessed in said floor and are in alignment with said ramp.

5. An electric switch as in claim 4 and in which said ramp in the interior of said end cover includes at least two sections and in which the surface of one section of said ramp is flush with the surface of one of said spaced terminals within the hollow of said end cover and the surface of the other end of said one section of said ramp rises above the surface of the other terminal of said pair of spaced terminals.

6. An electric switch as in claim 5 and in which the shoes of said contact means ride on opposite ramp sections in said end cover and make contact with opposite terminals of said pair of terminals.

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