Patent Publication Number: US-6698309-B2

Title: Direct drive adjustable pedal assembly

Description:
RELATED APPLICATION 
     This application is a continuation of co-pending application Ser. No. 10/040,096, filed Jan. 1, 2002. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The subject invention relates to an adjustable pedal assembly used in an automotive vehicle to vary the operating position of one or more of the foot pedals to mechanically or electrically control various vehicle systems, such as the clutch, brake and throttle systems. 
     2. Description of the Prior Art 
     Typically, adjustable pedal assemblies have used direct current electrical motors to rotate a drive cable that, in turn, rotates a worm gear to adjust the position of the pedal. Examples of such assemblies are shown in U.S. Pat. Nos. 5,632,183; 5,697,260; 5,722,302 and 5,964,125 to Rixon et al, 3,643,524 to Herring, 4,875,385 to Sitrin, 4,989,474 to Cicotte et al and 5,927,154 to Elton et al. Other assemblies eliminate the cable and connect the worm gear more directly to a pedal lever, as illustrated in U.S. Pat. Nos. 6,205,883 to Bortolon and 6,151,984 to Johansson et al. In order to stay within cost limitations, these assemblies require a relatively large number of parts, are noisy and imprecise in output. They also present difficult packaging parameters. 
     Strict standards have been developed in regard to the position of the brake pedal relative to the position of the accelerator pedal. Some assemblies address this requirement by using one motor to drive the adjustment of both pedals, as shown in the aforementioned U.S. Pat. No. 5,722,302. 
     SUMMARY OF THE INVENTION AND ADVANTAGES 
     The subject invention provides an adjustable pedal assembly comprising a support for mounting the assembly to a vehicle structure. A first pedal lever is pivotally supported for rotation about an operational axis relative to the support and a second pedal lever is pivotally supported for rotation about another operational axis relative to the support. A first adjustment mechanism interconnects the support and the first pedal lever and includes a first motor for adjusting the operational position of the first pedal lever between a first plurality of adjusted positions relative to the support. A second adjustment mechanism interconnects the support and the second pedal lever and includes a second motor for adjusting the operational position of the second pedal lever relative to the support. A controller is programmed to operate the first and second motors to simultaneously move the first and second pedal levers between the adjusted positions. The controller is also programmed to detect a stall of each of the motors. The assembly is characterized by the controller having a coordinator for automatically repositioning at least one of the motors to a corrected position in response to a stall by at least one of the motors thereby repositioning at least one of the pedal levers relative to the other to maintain a predetermined relationship between the pedal levers. 
     Accordingly, the subject invention provides an adjustable pedal assembly that reduces the total number of parts while providing a quieter and more precise and controllable adjustment. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
     FIG. 1 is a perspective view from the left of a preferred embodiment; 
     FIG. 2 is a perspective view from the right of the preferred embodiment; 
     FIG. 3 is an enlarged side view showing the motors and pedal levers; 
     FIG. 4 is a perspective view of the motor and drive control; 
     FIG. 5 is a perspective view of a controller of the subject assembly; 
     FIG. 6 is schematic view of the controller and motors; and 
     FIG. 7 is a graph showing the voltage timing. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the Figures, wherein like numerals indicate like or corresponding parts throughout the several views, an adjustable pedal assembly is generally shown at  10  in FIGS. 1 and 2. A support, generally indicated at  12 , is included for mounting the assembly to a vehicle structure. 
     A first pedal lever  14  is pivotally supported for rotation about an operational axis A with respect to the support  12 . The support  12  comprises a bracket having side flanges  16  and  18  that rotatably support a shaft  20 . A first adjustment mechanism, generally indicated at  21 , interconnects the support  12  and the pedal lever  14  for adjusting the operational position of the pedal lever  14  relative to the operational axis (A) between a plurality of adjusted positions. More specifically, the shaft  20  supports a first arm  22 . A line  24  depends from the shaft  20  and supports an attachment  26  that connects to the vehicle system for operating a system thereof, e.g., a brake system. As is well known in the art, any one of the shaft  20 , arm  22  or link  24  could be connected to an electrical generator for sending an electrical signal to a vehicle system instead of a mechanical output. The first adjustment mechanism also includes a guide, in the form of a rod  28 , movably supported by the support  12 , and the pedal lever  14  includes a collar  30  that is slidably supported by the rod  28 . The rod  28  is hollow and a nut (not shown) is moved axially within the rod  28  by a screw  32 , as shown in FIG.  4 . Such an assembly is illustrated in the aforementioned U.S. Pat. Nos. 5,722,302 and 5,964,125. However, as will be appreciated, the guide may take the form of a plate that slidably supports the pedal lever, the plate being either slidable or rotatable relative to the support. 
     The assembly  10  also includes a second pedal lever  34  pivotally supported for rotation about a second operational axis B with respect to the support  12 . The bracket defining the support  12  includes an ear  36  that supports a pin  38 . A second adjustment mechanism, generally shown at  41 , interconnects the support  12  and the second pedal lever  34  for adjusting the operational position of the second pedal lever  34  relative to the second operational axis B between a plurality of adjusted positions. The second adjustment mechanism includes a second arm  42  pivotally supported by the pin  38 . The upper end  44  of the second arm  42  is bifurcated to connect to a control cable, but as set forth above, the output may be electrical instead of mechanical. Again, the second adjustment mechanism  41  includes a guide, in the form of a rod  48 , movably supported by the support  12 , and the second pedal lever  34  includes a collar  50  that is slidably supported by the rod  48 . The rod  48  is hollow and a nut (not shown) is moved axially within the rod  48  by a screw  32 , as shown in FIG.  4 . This screw  32  and nut arrangement can be like that shown in the aforementioned Rixon et al patents. 
     The assembly  10  is characterized by each of the mechanisms  21  and  41  including an electrically operated motor  52  for sequentially moving in increments of movement. Such a motor  52  indexes when energized in a programmed manner. The normal operation consists of discrete angular motions of uniform magnitude rather than continuous motion. As shown in FIG. 6, each motor  52  includes a plurality of windings  54 . Each motor  52  has a housing surrounding the motor  52  and the screw  32  extends from the housing whereby the screw  32  and motor are a compact and universal unit. A motor housing is attached to the respective ends of the rods  28  and  48  with the screw  32  thereof extending into the associated rod  28  or  48  for moving the pedal levers  14  and  34  between the adjusted positions. It is important that the motor  52  be connected directly to the screw  32 , i.e., that the screw  32  extends out of and is supported by the housing surrounding the motor  52 . No loads from the operator to the pedal lever occur during the adjustment and the force required to move the collars  30  and  50  along the rods  28  and  48  is relatively low. However, the collars  30  and  50  cock or tilt relative to the axis of the rods  28  and  48  in response to a force on the pedal pads  68  or  70 . This tilting or cocking locks the collar  30  and/or  50  to the associated rod  28  or  48  whereby the force is transferred to the support  12  and not to the motor/screw  52 / 32  unit. 
     As shown in FIG. 6, a controller  56  is included for sending pulses of electrical energy sequentially to the windings  54  to incrementally rotate the motor  52  through a predetermined angle in response to each pulse. Each motor  52  includes a drive circuit  58  interconnecting the controller  56  and the respective drives  58 , which drives, in turn, energize the windings  54 . The controller  56  includes a memory, generally shown at  60  in FIG. 6, for summing the pulses to keep track of the operational position of the pedal lever  14  in all adjusted positions. The controller  56  also includes a timer  62  for measuring the time to reach a predetermined pulse width modulation sufficient to rotate the motor  52 . Attendant to this, the controller  56  includes latches each of which includes a voltage meter  64  for determining the voltage applied during the measured time to reach the predetermined pulse width modulation. The controller  56  includes a coordinator  66  for measuring the time to reach the predetermined pulse width modulation to alter the pulses of electrical energy to move the pedal lever  14  to the desired operational position in response to the time being outside a predetermined limit. In order to prevent the effects of the stall of a motor  52 , thereby adversely affecting the desired or programmed position of the pedal lever, the controller  56  detects the stall and adjusts the pedal lever position or shuts down the system, thereby maintaining a predetermined relationship between the first  14  and second  34  pedal levers. When each winding  54  of a motor  52  is energized, the current sent to the motor  52  rises until a pulse width modulation (PWM) set point is reached. The time from energizing the winding to reaching the PWM set point is based on the voltage applied to the winding and any load on the system. As shown in FIG. 7, a stalled motor  52  differs from a properly operating motor  52  by the measured time from energization of the windings to reaching PWM set point, the measured time for a properly operating motor being approximately twice the measured time for a stalled motor. Accordingly, the controller  56  measures the time and voltage to detect a stall, and when one occurs, corrects to reposition the motor to the programmed position thereby reestablishing the predetermined relationship between the first  14  and second  34  pedal levers. In addition, the controller  56  includes a software program for adjusting the respective operational positions of the first  14  and second  34  pedal levers in the predetermined relationship to one another. 
     It is desirable that the pedal levers  14  and  34  be adjusted in unison to accommodate different operators. The controller  56  sending equal signals to the respective motors  52  may accomplish this. However, in some cases where the mounting of the two pedal levers  14  and  34  differ substantially (as is in the embodiment illustrated herein), the controller sends disproportionate signals to the two motors to maintain equal or equivalent movement of the pedal pads  68  and  70  on the lower or distal ends of the respective pedal levers  14  and  34 . 
     An electrical connector  72  for the winding  54  extends out of the motor housing. The controller  56  and motor drive  58  are disposed within a separate housing from which extends an electrical connector  74  to connect to an electrical cable which divides and connects to the two motor connectors  72 . An additional electrical connector  76  connects to an electrical cable that leads to the vehicle system. 
     Obviously, many modifications and variations of the present invention are possible in light of the above teachings. The invention may be practiced otherwise than as specifically described within the scope of the appended claims, wherein that which is prior art is antecedent to the novelty set forth in the “characterized by” clause. The novelty is meant to be particularly and distinctly recited in the “characterized by” clause whereas the antecedent recitations merely set forth the old and well-known combination in which the invention resides. These antecedent recitations should be interpreted to cover any combination in which the incentive novelty exercises its utility. In addition, the reference numerals in the claims are merely for convenience and are not to be read in any way as limiting.