US2879359A - Switches with wiping contacts - Google Patents

Description

' March 24, 1959 A. B. PEARSON 2,879,359

\ SWITCHES WITH WIPING CONTACTS Filed Dec. 28, 1956 2 Sheets-Sheet 1 1 3 M m m j? Hi 14 it 71799 J79/0 55 3/ 56 ,qm/o/ 62/ BY March 1959 A. B. PEARSON swncnss WITH wxpmc; CONTACTS 2 Sheets-Sheet 2 Filed Dec. 28, 1956 INVEN TOR. fia/a 60r$0/7 W7 W United States Patent 2,879,359 S ITCHES wrm WIPING CONTACTS Application December as, 1956, Serial No. 631,286

12 Claims. .(Cl. 200-164) This invention relates to electric switches and to the make-and-break contacts thereof, that are generally of the so-called butt contacts class, that is, contacts that move relatively to abut upon each other, on surfaces generally at right angles to the direction of movement.

It is well known that the Contact surfaces of such contacts after they have engaged and disengaged in operation over a period of time, deteriorate by becoming corroded, pitted, and otherwise fouled, due partly at least to the current arcs that momentarily occur on the surfaces; and the contacts then cease to have theiroriginal current carrying capacity, and upon engaging may even fail to make the circuit Connected to them.

The contact surfaces must then be serviced to restore them or replaced by fresh ones.

Various means have been proposed to correct this defect of such contacts, the most effective being to construct the operating parts of the switch as a whole, so that in operation, when the contacting surfaces move into or out of mutual engagement, they will have a wiping movement, one on the other.

There is however a particular type of switch construction that has come into extensive use in which there is no known or obvious way to produce a true and efiEective wiping action at the contacts; namely, a switchin which the movable contacts that move into and out of abutting contact with stationary contacts, are carried by a switch member that is guided to move rectilinearly in a direction at right angles to the contacting surfaces.

In such a switch the contacts are usually held closed by spring pressure; and to be most effective the wiping action must occur while the contacts are being maintained fully closed and under the spring pressure.

The present invention has been made to overcome the said defect in a switch of the particular type mentioned.

The invention may be applied in various structures, but in order to present herein at least one practical application of the invention as required by law, a switch has been chosen for illustrative purposes herein having the following features, and embodying the invention in one form; the actual invention being that set forth in the appended claims.

An elongated rod-like element or reciprocator is reciprocated longitudinally and preferably vertically and is guided to have rectilinear movement, in the direction of its axis, and to prevent rotation around its axis.

A pair of stationary contacts are supported at opposite sides of the reciprocator.

The reciprocator has an aperture going through it transversely and extending longitudinally thereof; and a metal bridging bar has a portion intermediate its ends disposed in the aperture and projecting from opposite sides of the reciprocator; and on its ends carries contacts which move to engage and disengage stationary contacts in alignment therewith by rectilinear reciprocations of the reciprocator; and the bridging bar fits the aperture with small clearance, sothat it can freely slide longi- Patented Mar. 24, 1959 tudinally therein but is kept thereby from rotating around the reciprocator axis.

The bridging bar when in the aperture has opposite confronting edge portions loosely embracing side faces on the opposite sides of the reciprocator, which keep the bridging bar from shifting endwise, in the aperture.

The switch may be constructed so that the stationary contacts and bar contacts are normally closed, or normally open, or it may have both normally open and normally closed contacts.

In the case of normally closed contacts, and with the reciprocator in a normal down position, the bottom of the aperture is at its lower end and the bridging bar is in an upper portion of the aperture spaced from the aperture bottom.

In operation, the reciprocator moves upwardly and the aperture and side faces move with it; and ultimately the bottom of the aperture will engage the bar and raise it, opening the contacts.

Thus with normally closed contacts there is a longitudinal movement of the aperture and side faces relative to the bridging bar before the contacts open.

In the case of normally open contacts, and with the reciprocator in normal down position, the bottom of the aperture is at its upper end and the bridging bar is in engagement with the aperture bottom.

In operation the reciprocator moves upwardly, and the aperture and side faces and bridging bar move with it, and the bar contacts come into engagement with the stationary contacts, and the reciprocator and aperture and side faces have some further movement.

Thus there is movement of the aperture and side faces relative to the bridging bar after the contacts close.

This longitudinal movement of the aperture and of the opposite side faces of the reciprocator relative to the bridging bar, is variously utilized to give the bridging bar a transverse movement to wipe the contacts.

In one embodiment, the walls of the aperture are inclined at an angle to the axis of the reciprocator, that is at an angle to its up and down rectilinear movement; and with the contacts engaged, so that the bridging bar is held thereby from moving longitudinally of the axis, the inclined walls of the aperture propel the bar transversely during said relative movement, thereby wiping the engaged contacts. In this embodiment the side faces on the reciprocator may be parallel, and parallel to the axis.

In another embodiment, the aperture walls may be parallel to the axis; but the side faces are inclined at an angle to the axis, and during said relative movement propel the bar transversely of the axis, and wipe the engaged contacts.

In other embodiments, the aperture walls and the side faces may both be inclined at an angle to the axis, and during the said relative movement the bar is propelled transversely and wipes the engaged contacts in two directions concurrently.

When the reciprocator returns downwardly to close contacts, it will be apparent that said relative movement and wiping of the contacts will occur after they close; and when returning downwardly to open contacts the said relative movement and wiping of the contacts will occur before they open.

It will also be apparent that the direction of wiping on downward movement of the reciprocator is opposite to that upon upward movement.

With normally closed contacts, a spring is provided to yieldingly hold them closed.

With normally open contacts, a spring is provided to yieldingly hold the bridging bar upon the aperture bottom.

The springs in both cases provide spring pressure on the contacts when they are closed; and in consequence the said wiping action occurs under spring pressure.

In the above described forms of the invention, the inclined surfaces that propel the bridging bar transversely are on the reciprocator.

The invention also comprises a form in which the inclined surfaces are on the bridging bar; the end results in operation being the same as above described.

The objects of the invention are:

To provide switch contacts having the features of construction and made of operation above briefly described;

To provide a switch and contacts therefor having the features of construction and operation described briefly above.

The invention is fully disclosed in the following description taken in connection with the accompanying drawing in which:

Fig. 1 is a side elevational view of a switch to which the invention in one form is applied;

Fig. 2 is a fragmentary sectional view from the plane 2 of Fig. 1.;

Fig. 3 is an elevational view withparts in section showing separately a reciprocator of the switch of Fig. 1 in its normal position, the view being taken in the direction of the arrow 3 of Fig. 1;

Figs. 4, 5 and 6 are views illustrating the manner of mounting a contact bridging bar on the reciprocator as in Fig. 1; and Fig. 6 may be referred to the plane 6-6 of Fig. 3; and Fig. 5 may be referred to the plane 5 of Fig. 4;

Fig. 7 isa sectional view from the plane 7 of Fig. 1;

Fig. 8 is an elevational view of the reciprocator of Fig. .3 taken in the direction of the arrow 8 of Fig. 3;

Fig. 9 is a view similar to Fig. 3 with parts broken away showing the invention in another form;

Fig. 10 is an elevational view of the showing in Fig. 8 taken in the direction of the arrow 10 of Fig. 9;

Fig. 11 is a view similar to Fig. 1 illustrating a modification;

Fig. 12 is a cross sectional view from the plane 12 of Fig. 11, with parts below the section plane omitted;

Fig. 13 is a cross sectional view from the plane 13 of Fig. 11 with parts below the section plane omitted;

Fig. 14 is an elevational view of a reciprocator and parts mounted thereon of Fig. 11, shown separately, the view being taken in the direction of the arrow 14 of Fig. 11.

Referring to the drawing there is shown at 1 a main switch base or main frame molded from insulating material, having a preferably planar side face 2 extending forwardly from a support 3 on which it is mounted by screws 4.

A metal horizontal conductor 5 is mounted on the face 2 by screws 6-6 and at its forward end is provided with a circuit terminal screw 7; and at its rear end extends downwardly in an arm 8 having onits lower end a foot 9, on the upper side of which is a stationary contact 10.

Another metal horizontal conductor 11 with a terminal screw 12 at its forward end is mounted on the face 2 of the base by a screw 13 and has an upwardly extending "arm 14 terminating in a horizontal foot 15 on the upper side of which is a stationary contact 16.

The pair of stationary contacts 10 and 16 are in horizontal alignment.

Below the contacts 10 and 16 is another pair of stationary contacts 17 and 18 in horizontal alignment.

The contact 18 is on the under side of a horizontal foot 19 of an arm 20 extending downwardly from a horizontal metal conductor 21' mounted on the face 2 by screws 22-22 and having a terminal screw 23.

The contact 17 is on the under side of a horizontal foot 24 of an arm 25 extending downwardly from a horizontal conductor 26 mounted on the base by a screw 27 and having a terminal screw 28.

The horizontal conductors 5, '11, 21 and 26 may be seated in shallow recesses in the face 2 to position them.

The face 2 of the base has deep upper and lower recesses 29 and 30 therein and a rod like generally cylindrical reciprocator 31 of insulating material lies in the recesses and is retained therein by the conductor 5 see Fig. 2, and by a strap 32-mounted on the face 2 by screws 33, which bridge over the recesses.

The reciprocator 31 is free to slide longitudinally rectilinearly in the recesses 29-30 and is restrained from rotating therein by a tongue 34 on its upper end portion,'disposed in a groove 35 in the base, Fig. 2.

The reciprocator 31 extends below the base 1 and has a groove 36 in one side.

Below the base is an electromagnet comprising an E shaped core 37 on the central leg 38 of which is a winding 39.

The core has opposite .side plates 40 withteet 41 and is mounted on the support 3 by thefeet 41 and screws 42, these parts on only one side of the core being shown.

A magnet armature 43 is spaced a predetermined disstance below the core with a working air gap 44 and is connected to a non-magnetic stem -45 going upwardly through the middle leg38 of the magnet and connected to a head comprising a disc 46 and a plate 47, the disc 46 resting on top of the core 37, thereby positioning the armature 43.

Mounted on the plate 47 is an L-shaped piece 48 of molded insulating material, a horizontal leg 49 of the L-shape projecting into the reciprocator groove 36.

By this means when the winding 39 is energized and the armature 43 is attracted, it has a predetermined upward movement or stroke, being stopped on the magnet core, and the reciprocator 31 is moved upwardly with that same stroke; and upon deenergizing the magnet, the armature and reciprocator fall that predetermined stroke being stopped by the disc 46 ontop of the core.

A definite rectilinear up and down stroke for the re ciprocator is thereby provided.

Upper and lower bridging bars '50 and 51, of sheet metal, are carried by the reciprocator31, being mounted thereon in a particular manner to be described.

The upper bar 50 has contacts 52-53 on its under side normally engaging the stationary contacts 16 and 1t) and yieldingly held thereon by a loaded coil compression spring 54 surrounding the reciprocator 31 and reacting between the bar 50 a portion of the base.

The lower bar 51 has contacts 55 and 56 on its upper side normally spaced below the stationary contacts 17- 18, and a loaded coil compression spring 57surrounding the reciprocator, reacts upon the lower side of the bar 51, and upon a collar 58 formed on the reciprocator. In the normal condition of the parts in Fig. 1 the spring 57 is loaded but prevented from moving the bar 51 by means to be described.

The bridging bars 50 and 51 are mounted on the reciprocator as follows;

The .bars are alike and comprise each a short strip 59 of flat sheet metal, cut out at itsintermediate portion to provide a neck 60 and shoulders 61-61, Fig. 5.

The reciprocator 31 has upper and lower slits 62- 63 open at a side of the reciprocatorand extending in wardly horizontally; and at their inner ends opening into generally longitudinal apertures, 64-65. The necks 60 are disposed in the apertures.

The width of the apertures is slightly larger than the width of the bar neck to provide loose fit. The Walls of the apertures keep the bars .from rotating on the reciprocator.

The apertures 64-65 extend toward each other from the slits 62-63.

On opposite sides of the reciprocator, generally coextensivelongitudinallywith the apertures, flat faces 66- 66 are provided, spaced apart slightly less than the distance between the shoulders 61-61 on the bar 59.

When the'necks 60"are once inr theapertureayithe bars cannot rotate on the reciprocator in horizontal planes, except for a small lost motion provided by the loose fit, and cannot shift endwise because of the shoulders 61-61 overlapping the faces 66-66; and the contacts on the bars are therebyialways kept in vertical alignment with the stationary contacts.

In the form of the invention Figs. 1 to 7, the side faces 66-66 are parallel and parallel to the reciprocator axis. The apertures '64-.65 however have side walls extending longitudinally in the reciprocator, but inclined at an angle to thereciprocator axis, as plainly shown in Fig. 3.

To mount a bar, for example the bar 50, its neck 60 is. presented to the slit 62 as in Figs. 4 and 5 and the neck 60 is then slid into the slit 62 until the neck is aligned with the aperture 64 whereby the neck can enter the aperture, as shown by Fig. 3; and the shoulders 61- 61 will embrace the side faces 66-66.

With the parts of Fig. 1 in the normal position described, the apertures 64 and 65 are located so that the neck of the upper bar 50 is in the upper part of the upper aperture 64, and the neck of the lower bar 51 is at the upper end or bottom of the lower aperture 65, as shown in Fig. 3.

The loaded spring 57 under the lower bar 51 yieldingly holds the neck against the bottom of the aperture In operation, when the reciprocator 31 is moved upward by the magnet 37 through its said stroke, the upper aperture 64 and the side faces 66-66 move upwardly with it and the lower end or bottom of the aperture 64 comes up into engagement with the neck 60 of the upper bar 50 and then lifts the bar, raising the contacts 52-53 from the stationary contacts 16-10, against the pressure of the spring 54.

While the aperture 64 is thus moving upwardly relative to the neck 60, and with the contacts 52-53 of the bar still engaged with the stationary contacts 16- with spring pressure, the angularly: inclined sides of the slot propel the neck laterally, or transversely of the reciprocator, and the bar being thus propelled laterally, its contacts 52-53 are caused to slide transversely on the stationary contacts 10-16 with the aforesaid de sired wiping action. During this operation the shoulders 61-61 simply slide on the faces 66-66.

The bar contacts are finally lifted from the stationary contacts when the bottom of the aperture reaches the neck, and the aperture continues to move upwardly during the remainder of the stroke of the reciprocator.

Upon the return downward stroke of the reciprocator,

the contacts engage, and then as the reciprocator continues its downward stroke moving the aperture downwardly with it, the inclined sides of the slot produce the aforesaid wiping action on the contacts in the reverse transverse direction as will be understood. 'When the reciprocator moves upwardly it also moves the lower aperture 65 with it, and the neck 60 of the lower bar 51 being held against the bottom of the aperture 65 by the spring 57, the lower bar moves with the aperture.

The contacts 52-56 on the bar 51 thus come into engagement with the stationary contacts 17-18 when the neck is still on the bottom of the aperture and the bar movement is thereby stopped.

Continued movement of the reciprocator to complete its stroke, moves the aperture 65 upward relative to the neck 60 and the inclined sides of the aperture move the neck and bar transversely and produce the desired wiping action on the engaged contacts; and the spring 57 is compressed, holding the contacts engaged, under pressure.

When the reciprocator starts to return on its down ward stroke, the neck 60 is well down in the aperture 65 and the inclined sides of the aperture upon moving downwardly with the reciprocator, give the desired wiping action on the engaged contacts, until the neck is at the bottom of the aperture, and the final movement of the reciprocator and aperture pulls the bar and its contacts away from the stationary contacts.

The net result is that the normally closed contacts are wiped in one transverse direction before they open, and are wiped in the opposite transverse direction after they close again; and the normally open contacts are wiped in one transverse direction after they close, and are wiped in the opposite transverse direction before they open again.

In a single actuation of the switch of Fig. l, to operate and restore, both the normally closed and normally open contacts are wiped back and forth in opposite transverse directions; which effectively prevents the said deterioration thereof, sought to be accomplished by the invention.

It will also be noted that in the above described construction the contacts mutually engage on a transverse plane; and under spring pressure; and that the wiping action occurs on the plane of contact and while the contacts are under spring pressure.

Because of the spring pressure, the contacts resist being wiped on each other, and this increases the effectiveness of the wiping action in keeping the contacts clean.

In some cases however, the resistance to wiping, may cause the contact bar neck 60, to be pressed against the inclined side of the aperture, 64 or 65 with considerable force, and wear may tend to occur on the metal neck or on the side of the aperture and produce dust, accumulation of which may ultimately interfere with free movement of the neck in the aperture.

In such cases, it has been found that all wear and dust will be eliminated by making the reciprocator of Nylon; and this material additionally provides electrical insulation, isolating the two contact bars.

Another form of the invention is shown in Figs. 9 and 10.

In this form, the apertures 64A and 65A have their side walls parallel to the reciprocator axis, and as will be apparent do not cause the described wiping action. However, in this form the side faces 66A-66A are inclined to the axis; Fig. 10.

It will be apparent that the upward movement of these side faces relative to the bridging bars 50-51 upon upward reciprocator movement will propel them transversely and produce wiping action.

Also, it will be apparent that the wiping movement of the bars 50-51 in Figs. 9-10, will be lengthwise of the bars; whereas the wiping action in Figs. 3 and 8 above described will be cross-wise of the bars.

In this form, wiping action occurs both on the up stroke and on the down stroke of the reciprocator, and both under spring pressure, as in the first described form.

Other forms of the invention may be provided, by utilizing the principles above described, and since they will be readily apparent from the forgoing it is deemed unnecessary to illustrate and describe them in full, but suflicient to merely identify them as follows.

The apertures 64-65 may be inclined in the direction opposite to that of Fig. 3.

The side faces 66A may likewise be inclined in the opposite direction from that of Fig. 10.

A reciprocator may be provided with inclined apertures for example 64-65 of Fig. 3, and also provided with inclined side faces for example faces 66A of Fig. 10. In this case as will be understood, the longitudinal movements of the inclined apertures and inclined side faces, relative to the bridging bars will give them wiping movement lengthwise and crosswise at the same time.

In Figs. 11 to 14 is shown a modification in which inclined surfaces for causing wiping are one bridging bar 7 instead of being on a reciprocator "as in the above described forms.

In these figures a switch similar to that of Fig. 1 is shown with some of the parts omitted for simplification; and other parts given the same reference characters as in Fig. 1 to identify them and to simplify the following description.

Upper and lower sheet metal bridging bars 67 and 68 are provided having each a large perforation 69 therein, -for'telescoping over the reciprocator 70.

The reciprocator 70 is similar to the reciprocator 31 of Figs. 1 and 3 except that on its opposite sides are longitudinal flat faces 71-71 extending from its upper end to a terminus at 72 above a collar 73. The perforation 69has edges 74-74, Fig. 12, slidingly fitting with small clearance upon the fiat faces 71-71 of the reciprocator 70, and edges 75-75 spaced from the reciprocator to allow for transverse wiping movement of the bar.

The bridging'bars 67-68 have respectively, pairs of plates 78-78 and 79-79 depending therefrom and lying close to the said fiat faces 71-71 which prevent the bars from rocking around the reciprocator and from shifting endwise, and counteracts any tendency of the bar to tip out of the horizontal, as viewed in Fig. 11. The opposite pairs of plates are provided with horizontally aligned slots 80-80 and 81-81 therethrough.

Pairs of pins 82-82 and 83-83 extend through holes in the reciprocator being driven thereinto or tightly fitted therein and project laterally therefrom through the inclined slots 80 and 81, slidingly fitting the slots.

In some cases a single pin will suffice as will presently become apparent, but by providing two pins, both slidingly fitting the slot, any tendency of the bridging bar to rock out of the horizontal as viewed in Fig. 14 is counteracted. A spring 84 reacting between the upper bar 67 and a portion of the housing as shown, holds the 'bar contacts 52-53 normally engaged with the stationary contacts 16-10.

A spring 85 reacting between the collar 73 and the bar 68 holds the lower end of the slots 81 in engagement with the lower pin 83 and thereby holds the bar contacts 55-56 normally'disengaged from the stationary contacts 17-18.

The pins and slots are disposed to provide these conditions.

In operation, when the reciprocator 70 moves upwardly,'the lower bar 68, the pins 83-83 and the slots 81 all move upwardly in unison until the contacts 55-56 on on the bar are stopped on the stationary contacts 17-18.

The bar and slots then stop moving but the reciprocator 7 has further upward movement, moving the pins 83-83 with it, and the'latter, sliding in the slots, and due to their inclination, propel thebar 68 sidewise, giving the desired wiping action of the-contacts 55-55 on the engaged contacts 17-18 under'spring pressure as has been described hereinbefore.

At the upper bar '67, the upward movement of the reciprocator also'calzries the pins 82-62 with it, and causes the pins 82-82 to slide in the inclined slots 80-80, and due to the inclination of the slots the bar is propelled sidewise giving to the contacts 52-53, the said wiping action on the engaged contacts 16-10 under spring pressure; until-the upper pin 82 engages the tops of the slots 80. Further upward movement of the reciprocator and pins lifts thebar and'disengages the contacts.

'Upon return movement of the reciprocator, wiping of the contactsin the opposite direction and also under spring pressure occurs, as described hereinbefore for Figs. 1 to 8.

Theinvention is not limited to the exact details of construction illustrated and described and modifications thereof besides those mentioned may be made; and the invention is comprehensive of all of the same that come within thescope of the appended claims.

Insorne respects the subject-matter of this application mayheconsidered as :a-continuatton ofthe subjectrmatter of pending application, Serial .No. '5 60,655, filed I anuary 23, 1955, having the'sameassignee as this application.

1 claim:

1. An electric switch comprising a frame supporting a reciprocator-and guiding it for reciprocatorycmovement in a predetermined direction, and supporting stationary contactmeans; movable contact means; mountingmeans mounting'the wmovable contact means on the reciprocator to reciprocate therewith and to engage and disengage it with thestationary contacttmeans; the mounting means constructed to permit movement of the reciprocator in said predetermined direction relative to the movable contact means mounted on it while the movable contact meansis engaged 'with the stationary contact means; a

surface on thereciprocator inclined at an angle to the-direction of reciprocation and slidingly engaged with aiportion of the movable contact means during said relative movement, and thereby wiping the movable contact means on the stationary contact means in a direction transverse to the direction of reciprocatory movement.

2. A switch as described in claim 1 and in which the reciprocatoris elongated and is guided for'longitudinal reciprocatory movement, and the stationary contact means comprises a pair of stationary contacts on opposite sides of the reciprocator; and the movable contact means comprises an elongatedlbar extending laterally from opposite sides of the reciprocator and engages and disengages the stationary contacts by bridging and unbridging them; and the portion of the movable contact means slidingly engaged by the inclined surface is an intermediate portion of the bar.

3. Aswitch as described in claim 1 and in whichthe reciprocator ;is elongated and is guided for longitudinal reciprocatorysrnovement in the direction of a longitudinal axis, and the stationary contact means comprises a pair of stationary contacts on opposite sides of the reciprocator; and the .rnovable.contact means is an elongated bar extending through an aperture provided in the reciprocator and engages and disengages the stationary contacts by bridging and unbridging them; and an intermediate portion .of the bar engages walls of the aperture which prevents it from rotating on the reciprocator around the axis.

4. A switch as described in claim 1 and in which the reciprocator is elongated and is guided for longitudinal reciprocatory movement in the direction of a longitudinal axis, and the stationaryrcontact means comprises a pair .of stationary contacts on opposite sides of the reciprocator; and the movable contact means is an elongated bar extending through an aperture provided in the reciprocator and engages and disengages the stationary contacts by bridging and unbridging them; and an intermediate portion of the bar has shoulders overlapping and engaging opposite .side 'faces provided on the reciprocator which retain the bar againstendwise shifting on the reciprocator.

5. An electric aswitch comprising a frame supporting a reciprocator and guiding it for reciprocatory movement in a predetermined direction, and supporting a pair of stationary contacts at opposite sides of the reciprocator; a movable contact in the form of an elongated bar; mount ing means mounting the bar on the reciprocator in position to extend from opposite sides thereof and to cause it to reciprocate with the reciprocator to engage and disengage the stationary contacts by bridging and unbridging them; spring means reacting to hold the engaged contacts engaged with pressure; the mounting means comprising an aperture through the reciprocator through which the bar extends; the aperture being elongated longitudinally of the reciprocator so that it moves with the reciprocator relative to the bar when the-contacts are engaged; the aperture havinga surface'inclined at an angle to the direction of reciprocation and slidingly engaging an intermediate portion of the bar during said relative movement and thereby propelling the bar transversely to the direction of reciprocation to wipe the movable contact on the stationary contacts while engaged under spring pressure.

6. An electric switch comprising a frame supporting a reciprocator and guiding it for reciprocatory movement in a predetermined direction, and supporting a pair of stationary contacts at opposite sides of the reciprocator; a movable contact in the form of an elongated bar; mounting means mounting the bar on the reciprocator in position to extend from opposite sides thereof and to cause it to reciprocate with the reciprocator to engage and disengage the stationary contacts by bridging and unbridging them; spring means reacting to hold the engaged contacts engaged with pressure; the mounting means comprising faces provided on opposite sides of the reciprocator inclined at an angle to the direction of recipro cation; the bar having confronting shoulders over-lapping the faces; the faces being elongated longitudinally of the reciprocator so that they move with the reciprocator relative to the bar when the contacts are engaged; the said faces slidingly engaging the said shoulders of the bar during said relative movement and thereby propelling the bar transversely to the direction of reciprocation to wipe the movable contact on the stationary contacts while engaged under spring pressure.

7. An electric switch comprising a frame supporting a reciprocator and guiding it for reciprocatory movement in a predetermined direction, and supporting a pair of stationary contacts at opposite sides of the reciprocator; a movable contact in the form of an elongated bar; mounting means mounting the bar on the reciprocator in position to extend from opposite sides thereof and cause it to reciprocate with the reciprocator to engage and disengage the stationary contacts by bridging and unbridging them; the mounting means comprising an aperture through the reciprocator through which the bar extends; the aperture being elongated longitudinally of the reciprocator so that it moves with the reciprocator relative to the bar when the contacts are engaged; the aperture having a surface inclined at an angle to the direction of reciprocation and slidingly engaging an intermediate portion of the bar during said relative movement and thereby propelling the bar transversely to the direction of reciprocation to wipe the movable contact on the stationary contacts while engaged.

8. An electric switch comprising a frame supporting a reciprocator and guiding it for reciprocatory movement in a predetermined direction, and supporting a pair of stationary contacts at opposite sides of the reciprocator; a movable contact in the form of an elongated bar; mounting means mounting the bar on the reciprocator in position to extend from opposite sides thereof and to cause it to reciprocate with the reciprocator to engage and disengage the stationary contacts by bridging and unbridging them; the mounting means comprising an aperture through the reciprocator through which the bar extends; the aperture being elongated longitudinally of the reciprocator so that it moves with the reciprocator relative to the bar when the contacts are engaged; the aperture having a surface inclined at an angle to the direction of reciprocation and slidingly engaging an intermediate portion of the bar during said relative movement and thereby propelling the bar transversely to the direction of reciprocation to wipe the movable contact on the stationary contacts while engaged.

9. An electric switch comprising a frame supporting a reciprocator and guiding it for reciprocatory movement in a predetermined direction, and supporting stationary contact means; movable contact means; mounting means mounting the movable contact means on the reciprocator to reciprocate therewith and to engage and disengage it with the stationary contact means; the mounting means constructed to permit movement of the reciprocator in said predetermined direction relative to the movable contact means mounted on it while the movable contact means is engaged with the stationary contact means; a surface on the movable contact means inclined at an angle to the direction of reciprocation and slidingly engaged with a guide surface provided on the reciprocator during said relative movement, to cause the movable contact means to have a transverse wiping movement on the stationary contact means while engaged therewith.

10. The switch described in claim 9 and in which the inclined surface is the side wall of a slot in a portion of the movable contact means, and the guide surface on the reciprocator slidingly engaged therewith comprises a pin projecting from the reciprocator and into the slot.

11. An electric switch comprising a frame supporting a reciprocator and guiding it for reciprocatory movement in a predetermined direction, and supporting stationary contact means; movable contact means; mounting means mounting the movable contact means on the reciprocator to reciprocate therewith and to engage and disengage it with the stationary contact means; the mounting means constructed to permit movement of the reciprocator relative to the movable contact means while it is engaged with the stationary contact means; a first surface on the reciprocator; a second surface on the movable contact means; one of said surfaces being inclined at an angle to the direction of reciprocation and slidingly engaged with the other surface during said relative movement and thereby wiping the movable contact means on the stationary contact means in a direction transverse to the direction of reciprocatory movement.

12. In a switch, an elongated reciprocator mounted for longitudinal movement; a pair of stationary contacts at opposite sides of the reciprocator; a transverse aperture through the reciprocator having side walls extending generally longitudinally of the reciprocator but at an inclination to the longitudinal direction of said reciprocatory movement; a bridging bar having a portion intermediate its ends extending through the aperture and contacts on its ends engageable and disengageable with the stationary contacts upon reciprocations of the reciprocator; spring means disposed to hold the contacts under yieldable pressure, when engaged; the aperture being movable with the reciprocator after engagement of the contacts and the inclined walls of the aperture then giving movement to the bridging bar in the direction transverse to the direction of reciprocation; to produce a wiping action on the engaged contacts.

References Cited in the file of this patent UNITED STATES PATENTS 2,497,306 Landmeier Feb. 14, 1950

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