US3233056A

US3233056A - Adjustable condition-responsive plunger-operated snap-action electrical switch

Info

Publication number: US3233056A
Application number: US298535A
Authority: US
Inventors: Beck Walter; Roll Karl; Enssle Peter
Original assignee: WALTER BECK K G KONTROLL und F
Current assignee: WALTER BECK K G KONTROLL und F; Walter Beck Kg Kontroll- und Fernmessgerate
Priority date: 1962-07-30
Filing date: 1963-07-26
Publication date: 1966-02-01
Anticipated expiration: 1983-02-01
Also published as: FR1367841A; GB1044638A; NL295877A; DE1289168B; DE1899866U; DE1272421B

Description

Feb. 1, 1966 w. B K ETAL 3,233,056

ADJUSTABLE CONDITION-RESPON E PLUNGER-OPERATED SNAP-ACTION ELECTRICAL SWITCH Filed July 26, 1965 4 Sheets-Sheet l vvvvvvvv v II/III INVENTOR J B h." B l A BY master mkster moss Feb. 1, 1966 w. BECK ETAL 3,233,056 ADJUSTABLE CONDITION-RESPONSIVE PLUNGER-OPERATED SNAP-ACTION ELECTRICAL SWITCH 4 Sheets-Sheet 2 Filed July 26, 1965 INVENTOR Unlhr Blgk kad RQU Pei-u- Ehfl l Feb. I, 1966 w c T 3,233,056

ADJUSTABLE CONDITION-RES SIVE PLUNGER-OPERATED SNAP-ACTION ELECTRICAL SWITCH Filed July 26, 1963 4 Sheets-Sheet :5

INVENTOR Feb. 1, 1966 V w. BECK ETAL 3,233,056 ADJUSTABLE CONDITION-RESPONSIVE PLUNGER-OPERATED SNAP-ACTION ELECTRICAL SWITCH 4 Sheets-Sheet 4 Filed July 26, 1963 INVENTOR U lhr la k Kgrl 'h-hr Ens! United States Patent ADJUSTABLE CONDITION-RESPONSIVE PLUNG- ER-OPERATED SNAP-ACTION ELECTRICAL SWITCH Walter Beck, Stuttgart-Mohringen, Karl Roll, Stuttgart, and Peter Enssle, Kongen (N eckar), Germany, assignors to Walter Beck K.G., Kontrollund Fernmessgeriite, Stuttgart-Mohringen, Germany, a firm of Germany Filed July 26, 1963, Ser. No. 298,535 Claims priority, application Germany, July 30, 1962, B 68,232; Jan. 22, 1963, B 70,418 19 Claims. (Cl. 200-67) The present invention relates to a multipole snap-action electrical switch especially adapted for use in connection with the operation of a washing machine, and. it is an object of the invention to provide such a snap switch which is equipped with a number of contact springs in accordance with the number of poles and projecting between pairs of contacts, and in which these contact springs are operated by tonguelike strips, hereafter called tongues, which are acted upon by snap springs and control springs and are controlled by an actuating element which may be operated from the outside.

In order to permit the contacts of such multipolar snap switches to be opened and closed either simultaneously or successively as required especially in washing machines, the present invention provides a control member between the actauting element, which may be operated from the exterior, and the contact springs. By means of this intermediate control member it is possible to transmit the pressure which is exerted by the actuating element to the contact springs in the manner as may be desired in the particular snap switch.

If, for example, in a snap switch of the above-mentioned type which is provided with two pairs of contacts the corresponding contacts of both pairs are to be opened or closed simultaneously, the intermediate control memher is preferably provided in the form of a rocker which is mounted between the two contact springs which are associated with the pairs of poles, and which is acted upon by the central actuating element through an intermediate tongue and a snap spring which is associated with this tongue. This switch construction has not only the advantage that because of the use of a single tongue, a single snap spring, and a single control spring, it is extremely simple and therefore inexpensive, but it also insures by the provision of the intermediate rocker that the two contact springs will be moved exactly simultaneously,

In order to mount the rocker as well as the snap spring so that they are movable with as little friction as possible, but also to limit the bearing clearance as much as possible, the rocker and/or the snap spring are preferably mounted on knife edges or points. A firm engagement of the contact springs with the off contacts of the switch may also be attained if the bearing point of the snap spring in the rocker is spaced from the common pivot axis of the two contact springs at a distance which is equal to or greater than the distance of the bearing points of the rocker on the two contact springs from the same pivot axis. The critical position is then that position in which the bearing point of the snap spring in the rocker and the two bearing points of the rocker on the contact springs lie substantially in a common straight line which extends perpendicularly to the direction of the pivoting movement of the contact springs. In this critical position, the rocker is mounted so as to be very easily movable and can therefore rapidly follow the snapping movement which is produced by the snap spring.

In another switch according to a modification of the invention, the intermediate control member is provided 3,233,056 Patented Feb. 1, 1966 in the form of a crossarm or the like between the two contact springs. This crossarm is rigidly secured to the free end of a single tongue which is controlled by the mentioned actuating element and, in turn, controls the two contact springs through snap springs which are interposed between the ends of the crossarm and the contact springs. Also in this switch construction the tongue again effects a practically simultaneous switchIng operation of both contact springs since after the first snap spring has snapped over and the direction of force is therefore reversed, this will assist in the pivoting movement of the tongue with the result that immediately thereafter also the second snap spring will snap over and thereby compel the second contact spring to carry out its switching operation.

In this second embodiment of the invention as abovedescribed, the tongue is preferably pivotably mounted at one end so as to be freely pivotable about an axis which extends perpendicularly to the planes of the pivoting movement of the contact springs so that the tongue will be very easily movable. Each of the two ends of the crossarm which is secured to the other end of the tongue is then designed so as to support one end of one of the two snap springs, while the other end thereof is supported on one of the two contact springs.

It is further possible to provide this switch with a resilient member between the tongue and the outer actuating element, for example, in the form of a compression coil spring. This compression spring is preferably mounted so that its axis forms a continuation of the axis of the control spring. By interposing such a resilient member between the tongue and the actuating element the important advantage is attained that the force which is exerted by the actuating element upon the tongue is amplified by a force which is previously stored up by the resilient intermediate member, so that even if the outer actuating element is moved very slowly, the two snap springs will snap over very suddenly and therefore also effect an equally sudden switching operation of the contact springs.

According to a further modification of the invention the intermediate control member of the snap switch is provided in the form of a T-shaped or cross-shaped memher which is disposed between the two contact springs and is adapted to control them by means of a pair of tongues and a pair of snap springs each of which is interposed between one of the tongues and the associated contact spring. The bearing of this control member is preferably designed, for example, in the form of a point-suspension bearing or a ball socket, so as to permit the control member to be freely movable in four directions so that it may not only pivot back and forth about its pivot point but may also tilt back and forth about its central axis. Instead of producing a simultaneous switching operation of both contact springs as in the first two switch constructions as previously described, the switch according to this third embodiment of the invention per units, when a constant force is exerted by the outer actuating element upon the control member, that at first only one snap spring will be snapped over and the associated contact spring will thereby be switched over and that the snapping of the other snap spring and the switching of the other contact spring will not occur until the first contact spring has been switched over.

This subsequent operation of the contact springs is due to the fact that, if the control springs which act upon the tongues of the contact springs have diiierent spring characteristics and the control member is pivoted by the actuating element, this control member also carries out a lateral tilting movement in accordance with the strength of the two different control springs. This, in turn, has

the result that of the two tongues at first that tongue yields and is pivoted under the pressure of the actuating element which is acted upon by the weaker control spring. this tongue has snapped over and has thereby also switched over the associated contact spring, the continued and increased pressure by the actuating element produces a further pivoting movement of the control member and thereby a relative reverse tilting movement of this member, whereby the second tongue is pivoted against the action of the stronger control spring so that the associated second snap spring is then also snapped over and the associated contact spring is also switched over.

Apart from the fact that the respective switching times may be determined by making the control springs of a different appropriate strength, the switching times may be further varied by adjusting the position of the pivot bearing of the control member and thus the position of the latter when in its inactive state. For the same purpose it is also possible to limit the extent of the movement of one of the tongues by means of a stop member which is preferably also adjustable. The stop is then preferably applied on the second tongue which is swung over after the first tongue has been completely pivoted and its associated contact spring has been switched over. By this device it is not only possible to increase the idle stroke of the control member, i.e. the distance of its travel until it starts to act upon the tongue, the movement of which is limited by the stop, but it is also possible to prevent, during this idle stroke, the action of one tongue from affecting the action of the other tongue. If, however, the switching times are to occur in a quick succession, it may be advisable to provide both tongues with such stops.

If the control member which acts upon the tongues of the two contact springs is pivotably suspended at its free end on a fixed point of the housing and is then pivoted, the point of engagement of the central actuating element on the control member and also the points of engagement of the latter on the tongues of the contact springs will be horizontally displaced in accordance with the size of the pivoting angle. Such a horizontal displacement of these two points is, however, very undesirable since it may infiuence the different forces which are acting upon the control member.

In order to overcome the above-mentioned difi'iculties and disadvantages, the invention further provides according to a fourth embodiment that the free end of the control member may be pivotably suspended on a pivot pin or the like which, in turn, is pivotably suspended on a stationary part. The control member together with the pivot pin then form a lever system in which the free end of the pivotable pin on which the control member is pivotably suspended can yield to the same an extent by which the horizontal projection of the control member is shortened as the result of its pivoting movement. This means that the point on the control member on which the central actuating element engages can follow its vertical direction of movement and move likewise in this vertical direction. Consequently, the two other points on the control member which act upon the contact springs will also carry out a vertical movement.

In order to permit the control member to pivot on the pivot pin with as little friction as possible, the free end of the pivot pin is preferably made in the form of a crowned head which serves as a support for the end of the control member. For the same purpose, the pivoted end of the control member may also be provided with a longitudinal slot of a width greater than the diameter of the stem of the pivot pin. The two arms on the end of the control member which are formed by this slot then rest on the crowned head of the pivot pin at both sides of its stem.

Since the pivot pin itself should also be pivotably suspended with as little friction as possible, the upper end After the snap spring which is associated with of the pin should also be provided with a crowned head. The stem of the pin directly underneath this head then extends through a bore in the housing which is enlarged on its outer side to form a ball socket for the crowned head. In order to avoid any possible limitation of the pivotability of the pin by its stem, the diameter of the latter directly underneath the crowned head is preferably made considerably smaller than the diameter of the bore. The pivot pin may then pivot easily about a considerable angle toward all sides.

The features and advantages of the present invention will become more clearly apparent from the following detailed description thereof which is to be read with reference to the accompanying drawings of four different snap switches according to the invention which are especially suitable for washing machines, and in which FIGURE 1 shows a diagrammatic illustration of the principles of operation of a snap switch according to the invention;

FIGURE 2 shows a cross section which is taken along line 22 of FIGURE 3 of a two-pole switch with contact tongues which may be switched simultaneously;

FIGURE 3 shows a cross section which is taken along line 3-3 of FIGURE 2;

FIGURE 4 shows a plan view of an intermediate control member in the form of a rocker;

FIGURE 5 shows a cross section of the rocker according to FIGURE 4;

FIGURE 6 shows a cross section which is taken along line 6-6 of FIGURE 7 of a two-pole snap switch according to a modification of the invention;

FIGURE 7 shows a cross section which is taken along line 77 of FIGURE 6;

FIGURE 8 shows a diagrammatic illustration of the mode of operation of the switch according to FIGURES 6 and 7;

FIGURE 9 shows a cross section which is taken along line 9-9 of FIGURE 6;

FIGURE 10 shows a cross section which is taken along line 1t I0 of FIGURE 11;

FIGURE 11 shows a cross section which is taken along line 1111 of FIGURE 10;

FIGURE 12 shows a cross section which is taken along line 1212 of FIGURE 10;

FIGURE 13 shows a cross section of a two-pole snap switch according to a further modification of the invention with successively operating contact springs;

FIGURE 14 shows an enlarged detail view of a part of the switch according to FIGURE 13;

FIGURE 15 shows a cross section which is taken along line 1515 of FIGURE 14;

FIGURE 16 shows a bottom view of FIGURE 14 as seen in the direction of the arrow D therein; and

FIGURE 17 shows a diagrammatic illustration of the lever system as employed in the embodiment according to FIGURES 13 to 16.

FIGURE 1 illustrates the principles of application of a switch according to the invention to a washing machine. It shows diagrammatically a tub I of a washing machine, the bottom 2 of which is connected by a U-shaped pipe 3 with a standpipe 4, the upper end of which is closed. The upper part of this standpipe 4 contains a diaphragm switch as indicated diagrammatically at 5.

If tub 1 contains the amount of water as indicated at 6, the air cushion 8 between the column of water 7 and the diaphragm switch 5 will be compressed in accordance with the water level. If the water 6 rises in tub I to the level indicated by the line 9, the column of water 7 also rises to the level 9' which causes a further compression of the air cushion 8. This rise in pressure of the air cushion 8 then acts upon the diaphragm (not shown in FIG. 1 but seen at 15 at FIG. 2) of the diaphragm switch 5 and effects an operation thereof. If,

however, the level9 of the water 6 again drops in the tub I, the air cushion 8 again expands and, when it reaches the predetermined air pressure to which switch 5 is responsive, it causes the switch to reverse to its original position.

FIGURE 2 illustrates one preferred embodiment of the diaphragm switch 5 according to the invention. It comprises a closed inverted cup-shaped cylindrical housing 11 of insulating material which has a cover 12 on its lower end with a central air inlet 13. Between the edge 14 of housing and cover 12 a diaphragm 15 is clamped which is reinforced by a plate 16 of sheet metal and carries centrally on the latter a tappet 17.

As may be seen in FIGURES 2 and 3, housing 11 contains two pairs of

contacts

18, 19 and 21, 22 between which the free ends of contact springs 23 and 24 with contact studs thereon are inserted, the spring being rigidly secured at their other ends in the wall of housing 11.

When the switch is in the oil? position, contact springs 23 and 24 engage under preliminary tension with the

upper contacts

18 and 21. Contact springs 23 and 24 are further provided with

trapezoidal apertures

25 and 26 through which the two arms 27 of a rocker 28 interengage to form a bridge of insulating material between the two contact springs 23 and 24 and extends parallel to the horizontal swivel axis of these springs. This rocker 28 is illustrated in detail in FIGURES 4 and 5. As shown particularly in FIGURE 5, the arms 27 of rocker 28 have angular notches 29 which insure an accurate knife-edge suspension of the edges of the

apertures

25 and 26 of contact springs 23 and 24. Furthermore, as shown particularly in FIGURE 3, a spring strip 31 in the form of a tongue is rigidly secured at one end in the Wall of housing 11 and extends centrally between the two contact springs 23 and 24 and is acted upon at its upper side by a spring 32 which is mounted in a recess in housing 11. Tongue 31 is further acted upon by a snap spring 33 which engages at one end upon the tip 34 of tongue 31 and is held at the other end in a cylindrical recess 35 in rocker 28. In order to mount the rocker 28 so as to be pivotable as free as possible, this recess 35 is made of such a depth that its bottom is in a straight alignment with the notches 29 along the line a, as shown in FIG- URE 5.

The mode of operation of this switch as shown in FIGURES 2 to 5 is as follows:

If a rise in pressure of the air cushion 8 occurs in the standpipe 4, as shown in FIGURE 1, the diaphragm 15 will be deflected upwardly and will thereby move the tappet 17 in the direction of the arrow 36. This stroke of tappet 17, which is exerted upon tongue 31 against the action of spring 32, produces a pivoting movement of the tongue 31 in the direction of the arrow 37, whereby the snap spring 33 and thus also the rocker 28 are moved in the same direction. When during this pivoting movement of tongue 31, the tongue is in alignment with snap spring 33 and both of them then extend in the same direction as the contact springs 23 and 24 (when the latter are in their inoperative or off positions), snap spring 33 has also reached its dead-center position, so that immediately thereafter in the pivoting movement of tongue 31 snap spring 33 (together with rocker 28 and the two contact springs 23 and 24) will snap over to the other side, i.e. the on position, as indicated in broken lines in FIGURE 2. In this on position the current flows no longer through the

off contacts

18 and 21 but through the on

contacts

19 and 22. The switching operation which is caused by the rise in air pressure in thus completed.

If the pressure of the air cushion 8 in standpipe 4 again decreases, diaphragm 15 and the tappet 17 thereon are returned, by the action of spring 32, to their original position. Snap spring 33 thereby also snaps back to its original position and returns the contact springs 23 and 24 to their off position.

FIGURES 6 to 8 illustrate a similar construction of such a snap switch with two simultaneously moving contact springs.

Those parts of this switch which correspond to those as described with reference to FIGURES 1 to 4 are identified by the same reference numerals. However, in this embodiment of the invention the pivotable tongue 41 is not straight and clamped tightly at one end in the wall of housing 11, but it is T-shaped and its central arm is pivot-ably mounted at its free end so as to be pivotable about a horizontal axis 42 on the housing 11, while its crossarm 43 is bent so as to have offset portions intermediate its central part and its

ends

53 and 54. These ends are provided with

tips

44 and 45, each of which serves as a support for a

snap spring

46 or 47, respectively, On their other ends, snap springs 46 and 47 are mounted on

counterpoints

48 and 49 on the contact springs 23 and 24. In order to attain a free snapping movement of snap springs 46 and 47, contact springs 23 and 24 are provided with

elongated slots

51 and 52 into which the free ends 53 and 54 of crossarm 43 project when the switch is in the on-position, as indicated in dotted lines in FIGURE 6. In addition to the control spring 32, this switch isfurther provided with a storing spring 55 which is mounted between tongue 41 and the tip of tappet 17. This storing spring 55 is mounted so that its axis is in alignment with the axis of the control spring 32.

The mode of operation of the switch according to FIGURES 6 to 8 is in principle the same as that of the switch according to FIGURES 2 to 5. However, the addition of the storing spring 55 has the further advantage that this spring at first takes up and stores a part of the force which is exerted by the tappet 17 and then transmits this stored force to the pivotable tongue 41 at the moment when the two snap springs 46 and 47 snap over to the other side. This additional force of the storing spring 55 insures a very quick movement of tongue 41 and snap springs 46 and 47 through the straight dead-center position which, in turn, means a very quick switching action of the two contact springs 23 and 24 even if the stroke of diaphragm 15 and tappet 17 is very slow.

As may be seen especially in the diagrammatic illustra tion according to FIGURE 8, when the diaphragm 15 and tappet 17 thereon are moved in the upward direction, the storing spring 55 is at first compressed against the vertical component of the force of the two snap springs 46 and 47 and the control spring 32, not shown in FIGURE 8, and it therefore takes up and stores a force. While normally the snap springs 46 and 47 would not snap over until they and tongue 41 have been moved slightly beyond the dead-center position, as indicated in FIGURE 8 by the straight line b, the accumulated force of the compressed storing spring 55' will now, however, be so strong even shortly before the dead-center position b, that is, when the snap springs are in the position 46' and 47, that tongue 41 will be pushed already from this position through the dead-center position b. This, in turn, results in a snapping and subsequent release of the two snap springs to the position 46", 47" and a release of the storing spring to the position 55".

FIGURES 10 and 12 illustrate a third embodiment of the snap switch according to the invention. Those parts of this switch which are substantially equal to the corresponding parts of the two switches as previously described are again identified by the same reference numerals. This switch diii ers, however, in principle from those two switches by the fact that its two contact springs are not switched on or off simultaneously but successively. While these contact springs 23 and 24 are again provided with

longitudinal slots

51 and 52 as in FIG- URE 7, each of these slots is associated with a separate

pivotable tongue

61 or 62 which is clamped tightly at one end in the wall of housing 11 together with and centrally between the two webs of the

respective contact spring

23 or 24. Each

tongue

61 and 62 is acted upon by a

separate control spring

63 or 64. For controlling the separate movements of the two

tongues

61 and 62, a T-shaped control member 65 is provided which is mounted at the free end of its central arm 66 on the spherical head 67 of a pin so as to be freely pivotable in all directions. The crossarm 68 of the control member 65 is bent at both sides of the central arm 66 so as to be disposed within a lower pl-ane, As illustrated particularly in FIGURE 10, the other end of the central arm 66 projects beyond the crossarm 68 so that the point of engagement of the tappet on this projecting end is offset relative to the crossarm 68 and the lifting force which is exerted by the tappet will therefore be transmitted by the two tips '71 and 72 on the ends of crossarm 68 at a certain transmission ratio to the

tongues

61 and 62.

The mode of operation of this snap switch according to FIGURES l to 12 is as follows:

When the diaphragm 15 and thus also the tappet 17 is moved in the direction of the arrow 36 (FIGURE this causes a pivoting movement of the control member 65 in the direction of the arrow 73 against the action of the two control springs 63 and 64 which act upon the

pivotable tongues

61 and 62. Since these two control springs 63 and 64 have different characteristics and therefore exert different forces upon the associated

tongues

61 and 62, one of these tongues will yield sooner than the other under the pressure of the

tips

71 and 72 on control member 65, even though this pressure is at first equal on both tips. This first step in the operation in indicated in FIGURE 12 by the dotted-line position of the control member 65, in which due to the yielding of the control spring 63 the control member 65 has pivoted in the direction of the arrow 74. When tongue 61 has yielded so far that the associated snap spring 46 will sna-p over to the other side and will thereby also switch the contact spring 23 from the off-contact 13 into engagement with contact 19, control member 65 will naturally follow and carry out a further pivoting movement in the direction of the arrow 74. However, even though tongue 61 has been pivoted over, the force which is exerted by tappet 17 through the control member 65 and its tip 72 upon tongue 62 and its control spring 64 is then still insufficient to effect a snapping-over of the snap spring 47 and thus a pivoting-over of tongue 62, but it requires a further movement of tappet 17 before the control member 65 will carry out a pivoting movement in the direction opposite to the arrow 74, whereby-since the tip 7 1 on control member 65 has already reached its highest operative positionthe entire force which is transmitted by tappet 17 will then be exerted solely upon tongue 62. This force will now be sufficient to effect subsequently also the snapping-over of the snap spring 47 which is associated with tongue 62 and thus also the switching of contact spring 24 from the offcontact 21 into engagement with the on-contact 22. If subsequently the diaphragm and tappet 17 thereon eturn to their original inactive position in the direction of the arrow 36, the sequence of operations will occur in reverse to the sequence as described above.

The switching times may be changed not only by exchanging or adjusting the control springs 63 and 64, but also by providing suitable means for adjusting the bearing pin 67 and thus the pivot point of the control member 65 in the vertical direction. Another possibility of varying the switching times consists in limiting the extent of the pivoting movement of one or both

tongues

61 and 62 by providing a stop member 75 for the respective tongue as indicated particularly in FIGURE 10. Such a limitation of the pivoting range of one or both

tongues

61 and 62 not only determines the extent of the idle stroke of the control member 65, but it also prevents that the two spring systems will effect each other during this idle stroke.

FIGURE 13 finally shows a fourth design of the switch mechanism according to the invention, while FIGURES 14 to 16 show greatly enlarged detail views of some of the parts of this mechanism. Those parts of this switch which are similar to the corresponding parts of the switches as previously described are again identified by the same reference numerals. In this switch, the control member 65 is pivotably mounted at the end 76 of its longitudinal arm 66 on the head 77 of a pin 78 which, in order to reduce the friction between this head 77 and the end 76 of the control member 65 as much as possible, is made of a crowned or spherical shape. The upper edge 79 of this head 77 serves as a support of two arms 82 which surround the lower part 83 of the stem of pin 78 and are formed by a longitudinal slot 81 in the end of arm 66 of the control member. The lower part of the two arms 82 is trough-shaped to receive the rounded head 77, and the width of slot 81 is made only slightly greater than the thickness of the lower part of stem 83.

As may be further seen particularly in FIGURES l4 and 15, pin 78 is, in turn, pivotally mounted in the bottom 84 of housing 1 1. For this purpose, the bottom 84 is provided with a bore 85 of a size which is slightly larger than the diameter of the central part 86 of pin 78. At the upper side of the bottom 84 bore 85 is enlarged and this enlarged part is provided with a spherical surface 87 so as to form a ball socket in which the rounded head 38 is suspended so that pin 78 may freely pivot in any direction. In order to permit pin 78 to pivot about a sufiiciently large angle, the upper part 89 of stem 83 between the central part 86 and the upper head 88 is made of a considerably smaller diameter than bore 85.

FIGURE 17 finally illustrates diagrammatically the motional conditions of the control member 65 and its suspension system according to FIGURE 13. If the control member 65 would be pivotably mounted, for example, at a fixed point A and would then be pivoted in the direction of the arrow 73 to the dotted-line position, the two points B and C moving along an are about the point A would be shifted horizontally by the distance a toward the left. If the point B corresponds to the point of engagement 69 of tappet 17 on control member 65 and point C corresponds to the points of engagement of the two tips 71 of the control member on tongues 61, this means that these points of engagement would be shifted accordingly. In order to prevent this undesirable shifting, the invention provides that the point A is not made a fixed pivot point but provided on the end of pin 78 which, in turn, is pivotally suspended. If the control member 65 is then pivoted in the direction 73, it will follow the vertical movement 36 of the tappet 17 since its pivoting movement is caused by the tappet. Control member 65 can carry out this movement in spite of the shortening in the horizontal projection since pin 7 8 can yield toward the right in the direction of the arrow 91 and can thereby compensate for the distance a, as indicated by the dotand-dash line in FIGURE 17. This, in turn, means that the two points B and C then move in the vertical direction 36 and are still located vertically above their original positions B and C when the control member 65 is pivoted to its highest position.

Although our invention has been illustrated and described with reference to the preferred embodiments thereof, we wish to have it understood that it is in no way limited to the details of such embodiments, but is capable of numerous modifications within the scope of the appended claims.

Having thus fully disclosed our invention, what we claim is:

1. A multi-pole snap-action electrical switch comprising a housing; at least two pairs of spaced-apart contacts in said housing; a plurality of contact springs in said housing, each of said contact springs being secured at one end to said housing and swingable at said end while having contact points on the other end intermediate the contacts of a respective pair for alternately disengaging one of the contacts and engaging the other contact of the respective pair; at least one tongue member mounted at one end on said housing; actuating means within said housing operable from the exterior of said housing and connected with said tongue member for pivoting said tongue member in one direction about said end thereof; a control spring acting upon said tongue member in the opposite direction; at least one snap spring connected to said tongue member and at least to one of said contact springs for precipitously pivoting at least one of said contact springs from one of the contacts to the other contact of the respective pair when-said tongue member is swung slightly beyond a deadcenter position wherein said member is aligned with said snap spring; and a control member in said housing for transmitting movement of said actuating means to all of said contact springs, said control member comprising a rocker connecting said contact springs, said tongue member extending centrally between and substantially parallel to said contact springs, said snap spring connecting the free end of said tongue member centrally to said rocker, said actuating means bearing upon said tongue member near saidfree end thereof.

2. A switch as defined in claim 1, further comprising bearing means interconnecting said rocker and said contact springs to facilitate relative pivotal movement of said rocker'and said contact springs.

3. A switch as defined in claim 1, further comprising bearing means interconnecting said snap spring and said rocker to facilitate relative each other pivotal movement of said snap spring and said rocker.

4. A switch as defined in claim 1, further comprising first bearing means interconnecting said rocker and said snap spring, and second bearing means interconnecting said rocker and said contact springs, said bearing means permitting said rocker and said snap spring to be easily pivotable relative to each other and relative to said contact springs, said contact springs being mounted on said housing for swinging movement about a substantially common axis, said first bearing means being spaced from said common axis of said contact springs at a distance at least equal to the distance of said second bearing means from said common axis.

5. A switch as defined in claim 1, further comprising first bearing means interconnecting said rocker and said snap spring, and second bearing means interconnecting said rocker and said contact springs, said bearing means permitting said rocker and said snap spring to be easily pivotable relative to each other and relative to said contact springs, said contact springs being mounted on said housing for swinging movement about a common axis, said first and second bearing means being disposed substantially in alignment with one another along a line extending transversely to the direction of the pivoting movement of said contact springs.

6. A multi-pole snap-action electrical switch comprising a housing; at least two pairs of spaced-apart contacts in said housing; a plurality of contact springs in said housing, each of said contact springs being secured at one end to said housing and swingable at said end while having contact points on the other end intermediate the contacts of a respective pair for alternately disengaging one of the contacts and engaging the other contact of the respective pair; at least one tongue member mounted at one end on said housing; actuating means within said housing operable from the exterior of said housing and connected with said tongue member for pivoting said tongue member in one direction about said end thereof; a control spring acting upon said tongue member in the opposite direction; at least one snap spring connected to said tongue member and at least to one of said contact springs for precipitously pivoting at least one of said contact springs from one of the contacts to the other contact of the respective pair when said tongue member is swung slightly beyond a dead-center position wherein said member is aligned with said snap spring; and a control member in said housing for transmitting movement of said actuating means to all of said contact springs, said control member comprising a crossarm disposed between two adjacent contact springs and rigidly secured to the free end of said tongue member, one of said snap springs being pivotably connected to and acting upon one end of said crossarm and one of said contact springs, and a second snap spring being pivotably connected to and acting upon the other end of said crossarm and the other contact spring, said crossarm controlling the operation of said contact springs through the interposed snap springs.

7. A switch as defined in claim 6, wherein said tongue member is pivotably mounted on said housing so as to be swingable about an axis extending transversely to the direction of the pivoting movement of said contact springs.

8. A multi-pole snap-action electrical switch comprising a housing; at least two pairs of spaced-apart contacts in said housing; a plurality of contact springs in said housing, each of said contact springs being secured at one end to said housing and swingable at said end while having contact points on the other end intermediate the contacts of a respective pair for alternately disengaging one of the contacts and engaging the other contact of the respective pair; at least one tongue member mounted at one end on said housing; actuating means within said housing operable from the exterior of said housing and connected with said tongue member for pivoting said tongue member in one direction about said end thereof; a control spring acting upon said tongue member in the opposite direction; at least one snap spring connected to said tongue member and at least to one of said contact springs for precipitously pivoting at least one of said contact springs from one of the contacts to the other contact of the respective pair when said tongue member is swung slightly beyond a dead-center position wherein said member is aligned with said snap spring, a control member in said housing for transmitting movement of said actuating means to all of said contact springs; and comprising a resilient member interposed between said actuating means and said tongue member.

9. A multi-pole snap-action electrical switch comprising a housing; at least two pairs of spaced-apart contacts in said housing; a plurality of contact springs in said housing, each of said contact springs being secured at one end to said housing and swingable at said end while having contact points on the other end intermediate the contacts of a respective pair for alternately disengaging one of the contacts and engaging the other contact of the respective pair; at least one tongue member mounted at one end on said housing; actuating means within said housing operable from the exterior of said housing and connected with said tongue member for pivoting said tongue member in one direction about said end thereof; a control spring acting upon said tongue member in the opposite direction; at least one snap spring connected to said tongue member and at least to one of said contact springs for precipitously pivoting at least one of said contact springs from one of the contacts to the other contact of the respective pair when said tongue member is swung slightly beyond a dead-center position wherein said member is aligned with said snap spring, a control member in said housing for transmitting movement of said actuating means to all of said contact springs; and comprising a coil compression spring interposed between said actuating means and said tongue members.

10. A switch as defined in claim 9 wherein said compression spring and said control spring extend coaxially to each other at opposite sides of said tongue member.

11. A multi-pole snap-action electrical switch comprising a housing; at least two pairs of spaced-apart contacts in said housing; a plurality of contact springs in said housing, each of said contact springs being secured at one end to said housing and swingable at said end while having contact points on the other end intermediate the contacts of a respective pair for alternately disengaging one of the contacts and engaging the other contact of the respective pair; at least one tongue member mounted at one end on said housing; actuating means within said housing operable from the exterior of said housing and connected with said tongue member for pivoting said tongue member in one direction about said end thereof; a control spring acting upon said tongue member in the opposite direction; at least one snap spring connected to said tongue member and at least to one of said contact springs for precipitously pivoting at least one of said contact springs from one of the contacts to the other contact of the respective pair when said tongue member is swung slightly beyond a dead-center position wherein said member is aligned With said snap spring; and a control member in said housing for transmitting movement of said actuating means to all of said contact springs, a pair of said contact springs and an associated pair of said tongue members extending substantially parallel to each other and being mounted at one end on one side of the wall of said housing so as to be pivotable in the same direction about a common axis adjacent to said wall, a pair of said snap springs each being pivotably connected to the free end of one of said tongue members and to one of said contact springs near the other end thereof, said control member comprising a substantially cross-shaped member having a central arm disposed within a vertical plane centrally between said contact springs and pivotably suspended at one end on the opposite side of the wall of said housing so as to extend in the opposite direction to said contact springs and their associated tongue members, said actuating means adapted to act upon said central arm near the other end thereof, said control member having a crossarm, the ends of said crossarm engaging with and adapted to pivot said tongue members and through said snap spring also to pivot said contact springs but With a snap action in the opposite direction to the pivoting movement of said tongue members when said control member is pivoted by said actuating means.

12. A switch as defined in claim 11, further comprising bearing means for pivotably suspending said central arm on said first end thereof so as to be freely movable in four directions so that said control member can freely pivot within a vertical plane toward said tongue members and also tilt freely about its own longitudinal axis.

13. A switch as defined in claim 12, further comprising means for adjusting said bearing means.

14. A switch as defined in claim 11, further comprising stop means for limiting the extent of the pivoting movement of at least one tongue member.

15. A switch as defined in claim 12, in which said bearing means comprises a pin pivotably suspended at its upper end in said housing and having means on the lower end for suspending said control member thereon so as to be pivotable relative to said pin.

16. A switch as defined in claim 15, wherein said means on the lower end of said pin forms a crowned head, said central arm of said control member having an aperture near one end thereof, said pin extending through said aperture and said central arm resting on said crowned head.

17. A switch as defined in claim 15, wherein said means on the lower end of said pin forms a crowned head, said central arm having a longitudinal slot in one end of a width greater than the diameter of the stem of said pin adjacent to said crowned head, the two arms formed by said slot in said end resting on said crowned head.

18. A switch as defined in claim 16, wherein the Wall of said housing has a bore, the upper side of said bore being enlarged to form a ball socket, said pin extending through said bore and also having a crowned head on its upper end disposed within said ball socket.

19. A switch as defined in claim 18, wherein said bore has a diameter greater than the diameter of said stem of said pin so that said pin can pivot freely toward all sides.

References Cited by the Examiner UNITED STATES PATENTS 2,755,353 7/1956 Bachi 20067 2,939,927 6/1960 Kozel et al. 20083 2,975,251 3/1961 Beller et al. 20083 FOREIGN PATENTS 1,143,894 2/1963 Germany.

KATHLEEN H. CLAFFY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner.

Claims

1. A MULTI-POLE SNAP-ACTION ELECTRICAL SWITCH COMPRISING A HOUSING; AT LEAST TWO PAIRS OF SPACED-APART CONTACTS IN SAID HOUSING; A PLURALITY OF CONTACT SPRINGS IN SAID HOUSING, EACH OF SAID CONTACT SPRINGS BEING SECURED AT ONE END TO SAID HOUSING AND SWINGABLE AT SAID END WHILE HAVING CONTACT POINTS ON THE OTHER END INTERMEDIATE THE CONTACTS OF A RESPECTIVE PAIR FOR ALTERNATELY DISENGAGING ONE OF THE CONTACTS AND ENGAGING THE OTHER CONTACT OF THE RESPECTIVE PAIR; AT LEAST ONE TONGUE MEMBER MOUNTED AT ONE END ON SAID HOUSING; ACTUATING MEANS WITHIN SAID HOUSING OPERABLE FROM THE EXTERIOR OF SAID HOUSING AND CONNECTED WITH SAID TONGUE MEMBER FOR PIVOTING SAID TONGUE MEMBER IN ONE DIRECTION ABOUT SAID END THEREOF; A CONTROL SPRING ACTING UPON SAID TONGUE MEMBER IN THE OPPOSITE DIRECTION; AT LEAST ONE SNAP SPRING CONNECTED TO SAID TONGUE MEMBER AND AT LEAST TO ONE OF SAID CONTACT SPRINGS FOR PRECIPITOUSLY PIVOTING AT LEAST ONE OF SAID CONTACT SPRINGS FROM ONE OF THE CONTACTS TO THE OTHER CONTACT OF THE RESPECTIVE PAIR WHEN SAID TONGUE MEMBER IS SWUNG SLIGHTLY BEYOND A DEADCENTER POSITION WHEREIN SAID MEMBER IS ALIGNED WITH SAID SNAP SPRING; AND A CONTROL MEMBER IN SAID HOUSING FOR TRANSMITTING MOVEMENT OF SAID ACTUATING MEANS TO ALL OF SAID CONTACT SPRINGS, SAID CONTROL MEMBER COMPRISING A ROCKER CONNECTING SAID CONTACT SPRINGS, SAID TONGUE MEMBER EXTENDING CENTRALLY BETWEEN AND SUBSTANTIALLY PARALLEL TO SAID CONTACT SPRINGS, SAID SNAP SPRING CONNECTING THE FREE END OF SAID TONGUE MEMBER CENTRALLY TO SAID ROCKER, SAID ACTUATING MEANS BEARING UPON SAID TONGUE MEMBER NEAR SAID FREE END THEREOF.