Abstract:
A switch assembly for providing control signals to an electrical motor in a vehicle includes a printed circuit board having traces for communicating the control signals to a the electrical motor. A contactor module includes a set of depressible plungers and a set of contactor members. The contactor module is slideable with respect to the printed circuit board between an actuated position where the set of contactor members contact the traces and a deactivated position where the set of contactor members do not contact the traces. A housing for encasing the printed circuit board and the contactor module. The housing includes a set of detents for variably depressing the set of depressible plungers as the contactor module slides with respect to the printed circuit board. A tactile feedback is generated in response to the detents depressing the depressible plungers.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     Not Applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates in general to power seat switches and, and more specifically, to a low current power seat switch. 
     2. Description of the Related Art 
     Front vehicle seats are positionable to a plurality of positions for accommodating a passenger&#39;s height, leg length, and comfort level. The seat may be adjusted in multiple directions such as forward/rearward, up/down, tilt forward/tilt rearward, and recline up/recline down to accommodate a specific occupant. 
     Front vehicle seats that are powered utilize one or more electrical motors for electrically adjusting the vehicle seat to the desired position. Vehicle power seats are adjustable from 4 to 8 directions, for example. Typically, a respective motor is dedicated for a bi-directional movement of the seat (i.e., a slide motor for forward/rearward, a reclining motor for backrest recline up/recline down, etc). At least one set of seat switches is commonly disposed on the side of a seat or on an inner door panel. A single switch can be utilized for controlling the movement of the seat in multiple directions. For example, if a seat is a 6-way powered seat, a switch assembly will include 3 seat switch actuators for controlling the 6 possible directions of seat movement. If a seat is an 8-way powered seat, an additional switch may be utilized including an additional switch actuator for controlling the additional bi-directional movement of the vehicle seat. 
     Power seat switches include relays that transfer high current supplied from the power supply to a respective motor. When the seat switch is activated by the driver, a contact snaps down on a B+contact (e.g., butt contact) thereby completing an electrical connection within the switch. The switch is designed such that a crisp snap occurs as the contactor makes contact. This provides the driver with a good “feel” and helps increase of the life of the electrical connection by reducing the time of the arc across the electrical connection. Drivers have become accustomed to this “feel” as it provides a tactile feedback to the driver to confirm that contact within the switch has been made. 
     Power seats may also include power seat memory modules for recalling the seat position of one or more drivers. This allows various drivers utilizing the same vehicle to store their desired seating position into the memory of the memory module so when either driver activates a memory button or the vehicle passively recognized the respective driver, the vehicle seat will automatically be adjusted to the desired seating position of the respective driver. This alleviates the respective driver from having to adjust the vehicle seat to each respective position. The memory module includes either a microprocessor with relays or solid state electronics for transferring high current draws to the power seat motor. The high current switch is used in combination with the memory module for powering the motor. However, having high current switching capabilities in both the memory module and high current switch is an excess of high current switching components required to power the motor which results in added cost. 
     A low current control signal could be used to generate a control signal to the memory module to control the transfer of power to the seat motor without transmitting high current through the switch. The butt contact as used in the high current switch is undesirable for low current applications. To reduce cost of the switch, a low current sliding contact switch would preferably be utilized. The sliding contact switch may include a flexible electrical contactor that slidingly contacts electrical traces for making the electrical contact. The sliding motion scrubs the contacts clean which maintains a good circuit in low current applications; however, low current switches such as the sliding contact switch generates no tactile feedback which the operator has become accustomed to. 
     SUMMARY OF THE INVENTION 
     The present invention has the advantage of utilizing a low current switch that simulates a tactile feedback of a high current switch while providing control signals to a motor for controlling the motor. 
     In one aspect of the present invention, a switch assembly for providing control signals to an electrical motor in a vehicle includes a printed circuit board having traces for communicating the control signals to a the electrical motor. A contactor module includes a set of depressible plungers and a set of contactor members. The contactor module is slideable with respect to the printed circuit board between an actuated position where the set of contactor members contact the traces and a deactivated position where the set of contactor members do not contact the traces. A housing for encasing the printed circuit board and the contactor module. The housing includes a set of detents for variably depressing the set of depressible plungers as the contactor module slides with respect to the printed circuit board. A tactile feedback is generated in response to the detents depressing the depressible plungers. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an illustration of a vehicle seat according to a preferred embodiment of the present invention. 
         FIG. 2  is a plot of a force versus travel curve for a prior art high current switch. 
         FIG. 3  is a plot of a force versus travel curve for a prior art low current switch. 
         FIG. 4  is an illustration of a switch assembly according to a preferred embodiment of the present invention. 
         FIG. 5  is a cross-sectional perspective view of a contactor module according to a preferred embodiment of the present invention. 
         FIG. 6  is an exploded view of a contactor module according to a preferred embodiment of the present invention. 
         FIG. 7  is a bottom view of a contactor module and a housing according to a first preferred embodiment of the present invention. 
         FIG. 8  is a bottom view of a contactor module and a housing according to a second preferred embodiment of the present invention. 
         FIG. 9  is a bottom view of the contactor module of  FIG. 8 , in a pivoted position with the detent. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Now referring to the Drawings, and particularly  FIG. 1 , there is shown a driver seat  12  of a vehicle. The driver seat  12  includes a backrest portion  14  and a seat portion  16 . Both the backrest portion  14  and the seat portion  16  are adjustable for moving the driver&#39;s seat to a desired position. The backrest portion  14  may be independently adjusted to a recline up or recline down position. The seat portion  16  and the back rest portion  14  may be adjusted in combination to a forward or rearward position, an up or down position, and tilt forward or tilt rearward position. When adjusting the vehicle seat  12  to the forward or rearward position, a power seat switch  15  is actuated by the person seated in the vehicle seat  12 . The power seat switch  15  transmits a control signal to a power slide motor  18 . The power slide motor is engaged with a seat track  17  for moving the vehicle seat  12  forward or rearward along the seat track  17  to the desired position. 
     To adjust the vehicle seat  12  to an up or down position, the power seat switch  15  is actuated for either raising or lowering the vehicle seat  12 . The power seat switch  15  transmits a control signal to a rear lift motor  20 . The rear lift motor  20  may directly engage an adjustment mechanism for vertically displacing the vehicle seat  12  or may transmit power via a cable system to the adjustment mechanism for vertically displacing the vehicle seat  12 . 
     The vehicle seat  12  may also be adjusted to a recline position. To adjust the vehicle seat  12  to a recline position, a power seat switch  15  is actuated in a manner for either reclining the backrest  14  upward or downward to the desired position. The power seat switch  15  transmits the control signal to a reclining motor  22 . The reclining motor  22  transmits power directly or via a cable system to an adjustment mechanism for adjusting the backrest to the desired position. Similarly, the vehicle seat  12  maybe adjusted to a tilt position using a seat tilt motor (not shown). 
     Typically, a power seat switch is either a high current switch or low current switch. When utilizing a high current switch, the switch functions as a relay by transferring a high current draw from a power source such as a battery to a respective motor. Full current draw is carried through the contacts of the switch.  FIG. 2  is a curve of force vs. actuator post travel illustrating an effort level for a typical high current seat switch. A change in the effort level, shown generally at  23 , indicates where the contact snaps into an “on” position. When utilizing a low current switch, the switch generates low current control signals (e.g. milliamps) for controlling the transmitted power to a respective motor. As a result, high current draws are not generated within the switch.  FIG. 3  is a curve of force vs. actuator post travel illustrating an effort level for a typical low current seat switch. As indicated by the curve, the slope of the curve continues at a gradual increase without any significant dip in the effort level until the switch is fully depressed. As a result, the person depressing the typical switch does not feel the contact being made. 
       FIG. 4  illustrates a preferred embodiment of a low current switch. A set of removable seat control knobs  24  is disposed on a top surface of the switch assembly  15 . The control knobs  24  are slideably mounted to a plurality of fixed projections  28  extending from a cover plate  26 . The underside portions  25  of the control knob  24  which receives the fixed projections  28  of the cover plate  26  are slotted to allow the control knobs  24  to move and pivot about the fixed projections  28 . A plurality of moveable members  30  are disposed beneath the cover plate  26 . The plurality of moveable members  30  include protrusions  32  extending therefrom. The cover plate  26  includes a plurality of apertures  29  for allowing the protrusions  32  to extend therethrough for coupling to the control knobs  24 . In the preferred embodiment, two of the apertures are cross-shaped while the third aperture is slotted. The cross-shaped aperture allows the protrusions to be moved in a sideways direction as well as an upward/downward direction. For example, moving a first respective control knob forward or rearward is identifiable with an occupant&#39;s command to slide the vehicle seat  12  forward or rearward. Moving the first respective control knob upward or downward is identifiable with the occupant&#39;s command to move the vehicle seat  12  up or down. Rotating the first respective control knob in a counterclockwise or clockwise direction is identifiable with the occupant&#39;s command to tilt the vehicle seat  12  forward or backward. A second respective control knob having a respective protrusion extending through the slotted aperture is only moveable in two directions. Moving the second respective control knob in either direction is identifiable with the occupant&#39;s command for reclining the backrest forward or backward. 
     The moveable members  30  are disposed against a top surface of a housing  34  and are slideable along the top surface of the housing  34 . The housing  34  encases a plurality of contactor modules  36  and a printed circuit board  38 . The printed circuit board  38  includes traces for relaying control signals to a respective seat motor. Preferably, the traces of the printed circuit board are double sided in copper with a gold overplate. The material makeup of the printed circuit board material is CEM3. A plurality of apertures  35  that are directionally slotted are disposed along the top surface of the housing  34 . Each contactor module is oriented so that a portion of each respective contactor module aligns with a respective slotted aperture and extends therethrough for engaging a respective moveable member. As a respective moveable member slides along a top surface in a direction oriented with the respective slot, a respective contactor module engaged with the respective moveable member slides across the printed circuit board thereby making the necessary electrical contacts for transmitting the control signal to a respective seat motor. The control signal transmitted via the switch  12  is a low current control signal. 
       FIG. 5  illustrates the contactor module  36  according to a preferred embodiment. The contractor module  36  is disposed over a top surface  39  of the printed circuit board  38 . The contactor module  36  includes a set of contact members  40  for completing an electrical connection across a set of traces  41 . Preferably, the set of contact members  40  is a spring-like conductor made of nickel-silver with a gold overplate. The ends of the set of contact members  40  are bifurcated leafs for redundant circuits. When the contactor module  36  is seated between the set of traces as illustrated in  FIG. 5 , the contactor module  36  is at a neutral position. The neutral position is a deactivated position such that no electrical connection is made between the contact members  40  and the set of traces  41 . An actuated position is when an electrical connection is made between the contact members  40  and the set of traces  41 . When the contactor module  36  is displaced either forward or rearward from a neutral position to an actuated position, the set of contact members  40  completes an electrical connection across a respective pair of traces and transmits a control signal for powering the respective motor either clockwise or counterclockwise depending upon direction the contactor module  36  is displaced. For example, sliding the contactor module  36  in a first direction (e.g., forward) to a first actuated position will make an electrical contact between the contact members  40  and a first respective set of traces for transmitting a low current control signal to energize the electrical motor in a clockwise direction. Sliding the contractor module  36  in a second direction (e.g., rearward) to a second actuated position will make an electrical contact between the contact members  40  and a second respective set of traces for transmitting a low current control signal to energize the electrical motor in a counterclockwise direction. 
       FIG. 6  illustrates an exploded view of the contactor module  36  according to the preferred embodiment. The contactor module  36  includes an actuator body  42 . The actuator block  42  is preferably made of a plastic non-conductive material. Alternatively, the actuator block  42  can be made from any non-conductive material. A top extension  43  of the actuator block  42  is sized to extend through a respective aperture  35  of the housing  34  (shown in  FIG. 4 ). Locking tabs  47  are integrally formed with the actuator block  42  for slideably engaging the contactor module  36  to the top surface of the housing  34 . Alternatively other retention methods may be used for slidingly engaging the top surface of the housing  34 . The contact member  40  is affixed to the actuator block  42  so that each bifurcated leaf extends under the actuator block  42  for making contact with the printed circuit board  38 . Preferably, the contact member is staked to the actuator block  42 . A tubular bore  46  is formed in the actuator block  42  and extends from a first side surface  50  to a second side surface  51 . A set of plungers  44  is partially disposed within the tubular bore  46 . A compression spring  45  is disposed the between the set of plungers  44  for maintaining a resistance force on the set of plungers  44  when a compression force is placed on the compression spring  45 . 
       FIG. 7  illustrates a bottom view of the contactor module  36  assembled in the housing  34 . The contactor module  36  is shown disposed on the interior side  55  of the top of the housing  34 . The contactor module  36  is disposed between a first guide rail  56  and a second guide rail  57 . The first guide rail  56  and second guide rail  57  assist in maintaining a directional sliding motion as the contactor module  36  is slidingly moved forward or rearward. The housing  34  includes a set of detents  52  integrally formed on the interior side  55 . The set of detents  52  are angularly shaped. An apex  53  of each detent is formed furthest from the contactor module  36  corresponding to the deactivated position of the switch. The legs  58  of each detent  52  extend angularly outward from each detent  52  toward the contactor module  36 . 
     The set of detents  52  positionally maintain equilibrium between each spring loaded plunger within the tubular bore  46 . This is the result of the resistance forces generated by the spring force exerted on each plunger  44  and the retention force exerted by the legs of each detent  52 . The contactor module  36  is at a neutral position when the set of plungers  44  are seated at the apex  53  of each detent  52 . An occupant actuating a respective control knob forces the contactor module  36  to move in a respective direction as discussed earlier. As the contactor module  36  slidingly moves in the respective direction each plunger  44  slideably contacts a respective leg of each detent  52 . The respective sloped leg of each detent  52  exerts an increasing resistance force on the each plunger  44  causing the spring  45  to compress. Each plunger  44  recedes partially into the tubular bore  46 . The further the contactor  36  is displaced from the neutral position, the further each plunger  44  recedes into tubular bore  46  thereby generating a larger compression force within the spring  45 . The contact member  40  is transitioned over the printed circuit board  38  to electrical connect a set of traces for relaying the control signal to the respective motor. After the occupant releases the respective control knob the spring  45  is allowed to uncompress thereby exerting an outward force against each plunger  44 . The set of plungers  44  is allowed to expand along each increasing sloped leg until each plunger  44  reaches the neutral position. As each plunger  44  is seated in the apex  53 , the legs of the apex  53  prevents the plunger from moving in either direction. 
     As discussed earlier, the typical low current switch does not include a contact member that snaps down on a butt contact thereby generating a tactile feedback indicating that contact is made. To simulate the tactile feedback similar to that of the high current switch, at least one detent of the housing  34  includes bumped surface  54  along a respective leg. Preferably, the bumped surface  54  is a stepped surface which creates an abrupt movement of a respective plunger as opposed to a constant rate of change which is the result when traveling along a linear sloped surface of a respective leg. The abrupt movement of the respective plunger generates non-uniform rate of change in the depression of the respective plunger which provides a tactile feedback that simulates the “feel” of a high current switch. Alternatively other types of raised surfaced may be used as opposed to the stepped surface for generating the tactile feedback. A second bumped surface may be integrated on an opposing leg of the same respective detent or an opposing detent so that the tactile feedback may be generated when the contactor module  36  is actuated in the opposing direction. 
       FIG. 8  and  FIG. 9  illustrate a second preferred embodiment for generating a tactile feedback. The housing  35  includes a first detent  60  that is pivotable. As discussed earlier, as a control knob is actuated by an occupant, the contact module  36  slidingly moves in a respective direction. As the contact module  36  slidingly moves along the respective direction, the set of plungers passes a pivot point of the first detent  60  causing the first detent  60  to pivot. The rocking motion of the first detent  60  generates a tactile feedback similar to that of the high current switch. The spring  45  compressed by the second detent  61  and the first detent  60  provides the necessary force to return the contactor module  36  to the neutral position when the control knob is released by an occupant. 
     From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications to the invention to adapt it to various usages and conditions.