Abstract:
A switch assembly includes both a separating wedge member, which functions to maintain two electrical contacts out of electrical communication, and a second, camming element, which can be used to squeeze the contacts together when the switch assembly is actuated. In a first embodiment, the second element is of a generally conical shape. In a second embodiment, the second element is actually constituted by two side members having ramped surfaces. The interaction of the specially shaped contacts and camming element ensures proper mating of the contact members when the switch is actuated. In one preferred form of the invention, an undulating channel is formed in a housing of the switch to pinch connecting wires and assure a positive, reliable connection with the contacts.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention pertains to the art of electrical switches and, more particularly, to a switch assembly which utilizes a push button formed integral with a wedge member and at least one camming element for controlling the engagement state of a pair of electrical leads. When the push button is depressed, the wedge is moved from between electrical contacts, while the camming element pushes the contacts together.  
           [0003]    2. Discussion of the Prior Art  
           [0004]    It is well known in the art to provide a push button actuator for an electric or electronic switch. More specifically, it is known to utilize a plunger or push button within a housing to bias a spring member which, when pressure is applied to the push button, brings various contacts into electrical communication. Many of the recent designs represent attempts to eliminate either the number of moving parts, the number of total parts, the assembly time or assembly costs.  
           [0005]    In a known device, a push button actuator is used to unite two electrical contacts to complete a circuit therebetween. Specifically, it is known in the art to provide a switch wherein a separating element is located between two electrical contacts. Because the contacts are biased toward each other, when the separating element is removed, the two contacts come into electrical communication and complete the circuit. U.S. Pat. No. 3,902,032 to Koepke describes an electrical switch wherein a separator element is integral with a cylindrical plunger, such that when the plunger is lowered, the separator element is removed from between a pair of electrical contacts. A spring is included which biases the plunger upwards. The biasing action of the spring causes the separator element to fit between angled sections of the electrical contacts in a default position. However, in order for this system to work, the contacts must maintain both their deformability and their internal biasing toward each other. If the contacts were to lose either of these necessary characteristics, when the separator element is removed from between the contacts, the contacts would not naturally rejoin.  
           [0006]    In another system, the contacts are simply pushed together by an actuator. U.S. Pat. No. 1,911,444 to Fator describes a switch contained within a gripping device. In this design, two electrical contact members are biased away from each other such that, in the default position, the contacts are not in electrical communication. The entire apparatus is generally contained within a cylindrical housing, with the switch disposed in the center thereof. When the sides of the cylindrical housing are squeezed together, two plunger buttons are forced inward and push the contacts together. Although in such a system the contacts are pushed together rather than apart, the same limitations remain as discussed above.  
           [0007]    Each of the systems described above, as well as most others in the art, do not address a second problem. It is common to have the electrical contacts extend through the housing of the switch assembly to allow for connection to the remainder of the electrical circuit. This is normally accomplished by extending the contacts below the switch assembly and attaching a respective lead wire to each. However, when attached in this fashion, the wires are often simply hanging off of the contacts. This serves as a stress location and, as such, a potential failure point for the overall switch assembly.  
           [0008]    Switch assemblies, generally constructed in the manner set forth above, can be used in various environments. One particular environment of concern is in appliances, particularly clothes washing and drying machines. In such appliances, it is common to provide a control panel having various buttons which are associated with switches for enabling a consumer to select various operating parameters of the machine for a particular cycle. For instance, in the case of washing machines, it is common to provide a row of buttons which would enable the consumer to select a desired water temperature for both washing and rinsing cycles. It would not be uncommon to provide a bank of buttons in a single housing, with the buttons being associated with switches and further being interconnected such that the depression of one button would automatically cause the release of another button. For example, if the bank of buttons or switches control the selection between hot/hot, warm/warm, warm/cold and cold/cold wash and rinse temperatures respectively, the depression of the button associated with the warm/warm setting would automatically cause any other depressed button in the bank to be released. In general, cams and levers are utilized to interconnect the various push buttons to operate in this manner. In any event, since the useful life of such an appliance can be quite long, the switches must be extremely reliable. However, the overall construction of the switch assembly directly affects its associated cost, reflected in both the components themselves and the time needed for assembly and installation. In general, it is considered that the installation of conventional multi-switch devices are often difficult or time consuming. Primarily, the time and expense comes from being forced to install individual wires to at least two different locations of each switch in a known multi-switch device. In any event, there exists a need in the art for a push button switch assembly which overcomes the drawbacks of the prior art and which represents an overall switch which is easy to assemble, is cost effective and requires a minimum number of components, while being extremely reliable over a prolonged period of time.  
         SUMMARY OF THE INVENTION  
         [0009]    The present invention is particularly directed to a switch assembly including a housing and two electrical contacts which are maintained separated from each other by a wedge. The wedge is formed integral with a push button such that, when the push button is depressed, the wedge is forced out of engagement with the contacts. This allows the contacts to come into electrical communication. A camming element, which is integral with the push button, pushes the contacts together when the push button is depressed.  
           [0010]    The switch assembly includes a housing designed to hold the various parts of the switch assembly in place. Primarily, the contacts are attached to wires which extend outside the housing. Between the outside of the housing and where the wires are mounted to the contacts, the wires are placed in a wavy channel formed in the housing. When the housing is completely assembled, the wires are pinched and held in place between upper and lower sections of the housing which form the channel.  
           [0011]    In a first embodiment, the push button includes a conically shaped member, which defines the camming element, with an open wide face. The contacts are positioned inside the conically shaped member such that contact elements extend into a narrowing end of the conically shaped member. The wedge extends between the contacts such that, when in place, the wedge prevents the contacts from mating. When the push button is depressed, the wedge is forced from between the contacts and allows the contacts to mate. In addition, the conically shaped member presses against the contacts and forces the contacts together. A spring is included to maintain the push button and contacts in their default positions.  
           [0012]    In a second embodiment, instead of having a conically shaped member, two side members are provided with respective camming surfaces which essentially perform the same function as the conically shaped member of the first embodiment. In the default position, a wedge extends between the contacts and prevents their mating. When the push button is depressed, the wedge is removed and the contacts are engaged by the side members. Each side member unites with a bent section of each of the contacts and actually pushes them together. Two springs are included to maintain the push button and contacts in default positions.  
           [0013]    Additional objects, features and advantages of the invention will become more readily apparent from the following detailed description of preferred embodiments thereof, when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is a perspective view of a switch assembly constructed in accordance with a first embodiment of the invention, with the switch assembly being shown in a completely assembled state;  
         [0015]    [0015]FIG. 2 is a cross-sectional side elevational view of the switch assembly of FIG. 1 shown in the default or non-engaged position;  
         [0016]    [0016]FIG. 3 is a cross-sectional side elevation view of the switch assembly of FIG. 1 shown in an engaged position;  
         [0017]    [0017]FIG. 4 is a perspective view of a switch assembly constructed in accordance with a second embodiment of the invention, with the switch assembly being shown in an engaged position; and  
         [0018]    [0018]FIG. 5 is a perspective view of the switch assembly of FIG. 4, with the switch assembly being shown in a default or non-engaged position. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    A switch assembly  1  of the first embodiment of the invention is depicted in FIG. 1 and generally includes a housing  2 , with a cover  4 . Cover  4  is preferably defined by two spaced sides  5  and an integrally formed top  7 . As shown, top  7  includes a rectangular raised section  8  in the same shape as top  7  itself, but smaller in both length and width. Raised section  8  is provided with two push button apertures  9  through which push buttons  10  respectively protrude.  
         [0020]    The shape of housing  2  generally complements the general shape of cover  4 . More specifically, the housing  2  includes two upstanding spaced apart short sides  11 , two spaced apart long sides  12  and a bottom  13  (more clearly shown in FIGS. 2 and 3) which define an open rectangular box. On each of sides  12 , housing  2  includes a cover mounting tab  14 . Each mounting tab  14  is essentially constituted by a ramped protrusion which, when mated with a corresponding cover mounting aperture  16 , helps to secure cover  4  in a snap-fitting manner onto housing  2 . Because of the ramped shape of cover mounting tabs  14 , apertures  16  slide easily across the face of the cover mounting tabs  14 . Apertures  16  are generally the same shape as tabs  14 , but are larger in each dimension to permit installation and removal of the cover  4 . In addition, apertures  16 , as well as tabs  14 , are situated on both cover sides  5  and both sides  12  of housing  2 , respectively.  
         [0021]    Cover  4  also includes rounded slots  18  designed to extend around wires  20  which may project through one side  12  during installation of cover  4 . FIG. 1 shows two slots  18  and corresponding wires  20  extending through the side  12 . FIG. 1 also shows housing  2  with two identical parallel switch bays. However, the invention could include only a single switch bay in housing  2  or, alternatively, may include multiple switch bays. As each switch bay is identical, the description of one switch bay is sufficient to fully explain each of the included switch bays.  
         [0022]    [0022]FIGS. 2 and 3 depict the moving parts of switch assembly  1  in accordance with the first embodiment of the invention. As shown, push button  10  includes an upper projection  30 , a neck  32  and a lower projection  34 . FIG. 1 shows upper projection  30  extending through aperture  9  of cover  4 . Lower projection  34  is contained completely within housing  2 . The neck  32  joins upper projection  30  and lower projection  34 . Annularly disposed about neck  32  is a compression spring  36  which maintains push button  10  in a default position as shown in FIG. 2. Here, spring  36  extends between upper projection  30  and recessed portion  37  of housing  2 , and because of its shape, biases upper projection  30  away from housing  2 . Therefore, depressing push button  10  compresses spring  36  as both upper and lower projections  30  and  34  shift.  
         [0023]    In this embodiment, lower projection  34  is shown defined by a hollow, conically shaped member. Specifically, lower projection  34 , includes a wide bottom  38  which is open to allow two elongated contacts  40  and  41  to be inserted therein. Contacts  40  and  41  are preferably constructed of conductive metal, but may be formed from any electrically conductive material. Contacts  40  and  41  are biased apart, both internally and due to interactions with the remaining elements of switch assembly  1  as will be detailed further below. In addition, contacts  40 ,  41  includes a bent section  44  approximately half-way along its length. Bent section  44  is arranged such that, in the default position of the switch assembly  1 , it is not engaged by lower projection  34 . Disposed on each of contacts  40  and  41  is a respective contact element  46 , with contact element  46  being opposed to each other and adapted to unite when switch assembly  1  is actuated as shown in FIG. 3. Contact elements  46  are also constructed of an electrically conductive material and are placed to aid in mating of contacts  40  and  41 .  
         [0024]    Moving down the length of each contact  40 ,  41  away from contact element  46 , an angled section  48  is reached. Most preferably, each contact  40 ,  41  is generally L-shaped in side-view. Where each contact  40 ,  41  forms angled section  48 , contacts  40  and  41  are adapted to be engaged by a wedge  50 . Wedge  50  is integrally formed as part of push button  10  and is positioned with a narrow end between the two contacts  40 ,  41 . With push button  10  in its default position (FIG. 2), wedge  50  engages the contacts  40  and  41  to maintain their separation.  
         [0025]    Connected to one end of each contact  40 ,  41 , remote from a respective contact element  46 , is a wire  20  which extends into housing  2 . At the location where each contact  40 ,  41  joins a wire  20 , cover  4  and bottom  13  of housing  2  define a channel  52  into which wire  20  is placed. By forming channel  52  into a wavy or undulating configuration, wire  20  is pinched between cover  4  and bottom  13 . This gives greater flexibility in the placement of wire  20  outside the switch assembly  1  because there is little chance of each wire  20  losing its electrical communication with its respective contact  40 ,  41 .  
         [0026]    As indicated above, the position shown in FIG. 2 is the default or non-engaged position for switch assembly  1 . Here, contacts  40  and  41  are spaced apart. Wedge  50  is shown positioned between contacts  40  and  41  and accordingly prevents mating of contacts  40  and  41  by pushing them apart. Because of spring  32 , push button  10  is biased to cause lower projection  34  to move away from contacts  40  and  41 . As a result, contact elements  46  are spaced apart and no electrical current is permitted to flow therebetween. As such, when push button  10  is in the position shown in FIG. 2, no electrical circuit is completed.  
         [0027]    In contrast, FIG. 3 depicts switch assembly  1  in an engaged configuration. First, upper projection  30  of push button  10  is depressed against the biasing of spring  32 . This causes lower projection  34  of push button  10  to interengage contacts  40  and  41 . Because lower projection  34  is conically shaped, inner surfaces are ramped and define at least one camming surface. As contacts  40  and  41  slide along the inner surface of lower projection  34  towards the narrow end of the conically shaped member, contacts  40  and  41  are moved closer together. Because wedge  50  is integral with push button  10 , at the same time lower projection  34  moves into engagement with contacts  40  and  41 , wedge  50  is moved out of engagement with contacts  40  and  41 . Due to the internal biasing of contacts  40  and  41  and pressures exerted by lower projection  34 , contact members  40  and  41  abut one another.  
         [0028]    [0028]FIGS. 4 and 5 depict a switch assembly  201  in accordance with a second embodiment of the invention. As shown, switch assembly  201  includes a push button  210  having a base  211 , and an upper projection  230  which can be used to manually or electrically shift push button  210 . Push button  210  is adapted to various base guides  274  and respective overlapping of block guides  275 . In addition, a pair of blocks  276  limit the extent to which push button  210  may slide. Projecting out from base  211  of push button  210  are two side wedge members  278 , with ramped or camming surfaces  279 . Positioned between side members  278  are two contacts  240  and  241 . Contacts  240  and  241  are preferably constructed of a conductive metal, but may formed from any electrically conductive material. Contacts  240  and  241  are biased apart, both internally, and due to interactions with push button  210 . In addition, each contact  240  and  241  includes a bent section  244  along its length. Bent section  244  is placed such that, in a default position of switch assembly  201 , it is not engaged by a respective side member  278 . Disposed on each contact  240 ,  241  is a contact element  246 , positioned where the two contacts  240  and  241  unite when switch assembly  201  is actuated. Contact elements  246  are also constructed of an electrically conductive material and are placed to aid in the mating of contacts  240  and  241 . Additionally, each contact  240 ,  241  includes a section  288  which is affixed over one of the blocks  276 .  
         [0029]    A wedge  250 , integrally formed with base  211  of push button  210  includes a narrow end which projects between contacts  240  and  241 . With push button  210  in its default position, wedge  250  extends well between contacts  240  and  241  and forces them apart (FIG. 5). Extending between each block  276  and push button  210  is a spring  284  which biases push button  210  to a position which forces wedge  250  between contacts  240  and  241 . Springs  284  are obscured from view in FIG. 4 as they are compressed between base  211  of push button  210  and blocks  276 .  
         [0030]    As represented in FIG. 4, when push button  210  is depressed, it moves toward blocks  276  and compresses springs  284 . Because side members  278  are integral with push button  210 , movement of push button  210  causes side members  278  to shift such that ramped surfaces  279  engage bent sections  244  of contacts  240  and  241  thereby forcing contacts  240  and  241  together. In addition, because wedge  250  is integral with base  211  of push button  210 , wedge  250  also moves when push button  210  is depressed. Therefore wedge  250  is shiftable from its default position, between contacts  240  and  241  at bent sections  244  (FIG. 5), to below bent sections  244  whereat contact elements  246  become engaged (FIG. 4). Wires (not shown) are attached to contacts  240  and  241 , preferably via screws  290  in order to enable activation of switch assembly  201 .  
         [0031]    Although described with reference to preferred embodiments, it should be readily understood that various changes and/or modifications can be made to the invention without departing from the spirit thereof. For example, although the switch assemblies  1  and  201  of the invention have been described as being momentary switches where the switch returns to the default position when the pressure being applied is removed, it would be easy for one of ordinary skill to use the switch assemblies of the invention as on-off type switches. In any event, the invention is only intended to be limited by the scope of the following claims.