Accelerator module for electric vehicle

An accelerator module for an electric vehicle has a pivotal actuator upon which is mounted a wiping element for wiping engagement with variable and constant resistance elements formed upon a printed circuit board mounted within a housing. A normally-open switch mechanism is also mounted upon the printed circuit board, and in order to delay the closure of the normally-open switch mechanism from its OPEN state to its CLOSED state, the actuator is provided with a spring-biased overtravel plunger mechanism which engages a push-button element of the switch mechanism so as to retain the switch in its OPEN state until the actuator has been moved a predetermined distance corresponding to a predetermined amount of depression of the accelerator pedal of the electric vehicle.

FIELD OF THE INVENTION
 The present invention relates generally to electrical switches and variable
 electrical resistance mechanisms used in conjunction therewith, and more
 particularly to an electrical switch and variable electrical resistance
 mechanism which may be readily incorporated within an accelerator module
 utilized in connection with electric vehicles.
 BACKGROUND OF THE INVENTION
 Electrical switches and variable electrical resistance mechanisms are
 utilized in many different applications in order to, in effect, undergo
 and operatively sense or determine a positional change in response to
 movement of an operatively associated movable member, and furthermore, to
 provide or generate a corresponding electrical signal, indicative of such
 positional change, to an electrical controller. An exemplary use of such
 switches and variable electrical resistance mechanisms is in conjunction
 with an accelerator pedal of an electric vehicle whereupon depression of
 the accelerator pedal, the variable electrical resistance mechanism will
 generate an electrical signal which varies in proportion to the
 displacement or depression of the accelerator pedal which, of course,
 corresponds to the degree of acceleration desired by the vehicle operator.
 The variable resistance mechanism, as is normally the case with a
 potentiometer or other similar variable electrical resistance devices or
 mechanisms, is mechanically linked to the movable member so as to sense or
 determine the displacement or movement of the movable member over a
 predetermined range of movement. More particularly, in the case of
 utilizing such a system in connection with an accelerator pedal of an
 electric vehicle, the aforenoted related U.S. patent application Ser. No.
 08/603,041 discloses a system wherein a potentiometer shaft is operatively
 connected to an arm or the like which extends from the accelerator pedal
 so as to be rotated in response to the depression or displacement of the
 accelerator pedal, and a lever or actuator, carrying a wiper element for
 defining a wiping contact with respect to constant and variable electrical
 resistance elements disposed upon a printed circuit board of the
 electrical assembly, is provided upon the rotary shaft.
 The aforenoted system, more specifically disclosed within the aforenoted
 related U.S. patent application Ser. No. 08/603,041, is illustrated in
 FIGS. 1 and 2 of the drawings of the present patent application, wherein
 such drawing FIGS. 1 and 2 of the present patent application correspond to
 FIGS. 1 and 2 of the aforenoted related U.S. patent application Ser. No.
 08/603,041 drawings, however, the details and description of the
 illustrated and disclosed system of the aforenoted related U.S. patent
 application Ser. No. 08/603,041 are only briefly described hereinbelow,
 and only the relevant component parts of the system have been designated
 by reference characters, as is necessary to the understanding of such a
 related system for background purposes of this patent application and the
 invention more fully described later herein. More particularly, the
 referenced system is generally indicated by the reference character 10 and
 comprises a normally-open switch 20 which is disposed within a housing
 100, and a printed circuit board 300, upon which is disposed a constant
 electrical resistance element 32 and a variable electrical resistance
 element 34, which is also disposed within the housing 100. An actuator
 body member 220, which has mounted thereon wiper elements 420 for wipingly
 engaging the constant electrical resistance element 32 and the variable
 electrical resistance element 34, is pivotally disposed within the housing
 100 as a result of being fixedly mounted upon a rotatable shaft 60 by
 means of a sleeve portion 230. The sleeve portion 230 of the actuator body
 member 220 is axially or longitudinally fixed upon or with respect to the
 shaft 60 by means of a collar 70 and a set screw 74, wherein the set screw
 74 extends through a threaded bore 72 defined within the collar 70 so as
 to engage the shaft 60. The shaft 60 is, of course, operatively connected
 to the movable member or accelerator pedal, not shown. A torsion spring
 170 biases the actuator body member 220 toward the position illustrated in
 FIG. 1 such that the actuator body member 220 is normally engaged with an
 actuator push-button 22 of the normally-open switch 20.
 While the aforenoted system has in fact proven to be quite satisfactory
 from an operational point of view in that the same achieves its
 operational objectives in a reliable manner in order to properly control,
 for example, the acceleration mode requirements of the associated electric
 vehicle, it is often desirable, particularly in connection with the
 operation of electric vehicles, that the accelerator pedal be permitted to
 undergo a predetermined amount of limited travel or depression by the
 vehicle operator prior to electrical power actually being generated and
 delivered or transmitted to the drive train of the vehicle. Considered
 from a different operative perspective, it is desirable that the
 deliverance or transmission of actual electrical power to the vehicle
 drive train be effectively delayed for a predetermined amount of time
 after the accelerator pedal has undergone a predetermined amount of
 displacement, movement, or depression by the vehicle operator, wherein
 such predetermined amount of delayed power transmission time also
 encompasses a corresponding predetermined amount of pivotal or arcuate
 movement or displacement of the actuator body member and the wiper
 elements carried thereon with respect to the constant and variable
 electrical resistance elements of the printed circuit board prior to the
 closing of the normally-open switch mechanism. There are several reasons
 for achieving such a mode of operation. Firstly, such a mode of operation
 effectively limits any sudden "lurching" of the vehicle when the vehicle
 is initially moved from a stopped condition or state which would otherwise
 occur if electrical power is instantaneously transmitted or delivered to
 the vehicle drive train, without any predetermined delay, when the vehicle
 accelerator pedal is depressed by the vehicle operator. Viewed from a
 slightly different perspective, the incorporation of such a delay or
 operative mechanism within the vehicle comprises, in effect, a safety
 feature whereby acceleration or movement of the vehicle from a stopped
 position or condition cannot be inadvertently achieved merely as a result
 of incidental or limited contact or depression of the vehicle pedal.
 Secondly, such a mode of operation is desirable from an ergonomic point of
 view. Thirdly, such a mode of operation permits adjustability of the
 voltage signal output level as a function of the movement or depression of
 the vehicle accelerator pedal, and still further, or fourthly, such a mode
 of operation or use of such a delay or operative mechanism permits the
 pedal travel, movement, or depression to be adjusted or compensated for so
 as to permit the system to be operative in connection with different basic
 switch mechanisms or assemblies.
 In addition to the foregoing, it sometimes happens that the normally-open
 switch mechanism will undergo or experience shock or impact forces if the
 accelerator pedal is suddenly or quickly released whereby the actuator
 body member is returned to its initial arcuate position and into
 engagement with the push-button element of the switch mechanism in a
 substantially rapid manner under the biasing influence of the torsion
 spring. Under such circumstances, it is possible that the normally-open
 switch mechanism could undergo or experience breakage, damage, distortion,
 and the like, and in a similar manner, stresses are likewise imposed upon
 the solder joints that secure the switch mechanism upon the printed
 circuit board.
 A need therefore exists in the art for a new and improved accelerator
 module for an electric vehicle which incorporates therein a variable
 resistance control mechanism, assembly, or arrangement wherein the
 transmission of electrical power to the drive train of the electric
 vehicle is effectively delayed for a predetermined amount of time during
 which the vehicle accelerator pedal, and the actuator body member
 operatively connected thereto, can undergo an initial displacement or
 movement whereby accelerated movement of the electric vehicle from an
 initially stopped condition or state can be accomplished in accordance
 with a desired acceleration curve and in a safe manner, and in addition,
 impact, shock forces, and stresses, upon the switch mechanism, and its
 mounting joints upon the printed circuit board, can be effectively
 eliminated or substantially reduced.
 OBJECTS OF THE INVENTION
 Accordingly, it is an object of the present invention to provide a new and
 improved accelerator module for an electric vehicle.
 Another object of the present invention is to provide a new and improved
 accelerator module for an electric vehicle which overcomes the various
 drawbacks and disadvantages characteristic of known electric vehicle
 accelerator modules.
 An additional object of the present invention is to provide a new and
 improved accelerator module for an electric vehicle wherein transmission
 of electrical power to the vehicle drive train is effectively delayed a
 predetermined amount of time after the vehicle accelerator pedal is
 depressed and displaced or moved a predetermined distance as a result of
 the incorporation of a delay mechanism upon the actuator body member of
 the accelerator module.
 A further object of the present invention is to provide a new and improved
 accelerator module for an electric vehicle wherein the delay mechanism of
 the actuator body member of the accelerator module also serves to provide
 shock absorption and impact protection for the normally-open switch
 mechanism of the accelerator module.
 SUMMARY OF THE INVENTION
 The foregoing and other objectives are achieved in accordance with the
 teachings of the present invention through the provision of a new and
 improved accelerator module for an electric vehicle wherein, as was the
 case of the accelerator module disclosed within the aforenoted U.S. patent
 application Ser. No. 08/603,041, the actuator body member is pivotally
 mounted upon the accelerator pedal input shaft, and the actuator body
 member has a wiper mechanism, comprising wiping elements, mounted thereon
 for wipingly engaging the variable and constant electrical resistance
 elements formed upon the printed circuit board, however, in lieu of the
 non-pivotal, distal end portion of the actuator body member directly
 engaging the normally-open switch mechanism when the vehicle accelerator
 pedal is not depressed, the actuator body member of the present invention
 is provided with a spring-biased plunger mechanism which is movable
 between two extreme positions depending upon the disposition of the
 actuator body member as a result of the depression or non-depression of
 the vehicle accelerator pedal.
 As a result of the foregoing structure and system, when the vehicle
 accelerator pedal is initially depressed, the actuator body member is
 initially rotated or pivoted such that the wiping mechanism thereof begins
 to wipingly engage the constant and variable electrical resistance
 elements formed upon the printed circuit board in order to begin
 transmission of electrical power to the vehicle drive train, however, the
 spring-biased plunger mechanism is maintained engaged with the switch
 button of the normally-open switch mechanism under the biasing influence
 of the plunger mechanism coil spring so as to retain the normally-open
 switch mechanism in its normally OPEN state whereby actual transmission of
 electrical power to the vehicle drive train is delayed until the
 accelerator pedal, and the actuator body member operatively connected
 thereto, is pivotally moved or displaced a predetermined distance at which
 time the spring-biased plunger mechanism is physically disengaged from the
 switch button of the normally-open switch mechanism whereupon the
 normally-open switch mechanism is now disposed in its CLOSED state and
 electrical power is able to in fact be transmitted to the vehicle drive
 train.
 As a result of the aforenoted structure, the desired acceleration curve of
 the electric vehicle is able to be accomplished in an ensured manner. In
 addition, in light of the interdisposition of the spring-biased plunger
 mechanism between the switch mechanism and the actuator body member, when
 the actuator body member is rapidly returned to its initial state under
 the influence of its biasing torsion spring, such as, for example, when
 the vehicle operator suddenly releases the accelerator pedal from its
 depressed state, the spring-biased plunger mechanism will absorb any shock
 or impact forces which would otherwise be impressed upon the switch
 mechanism thereby eliminating or substantially reducing severe damage to,
 or stress upon, the switch mechanism and its mounting upon the printed
 circuit board.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
 Referring now to the drawings, and more particularly to FIG. 3 thereof, a
 new and improved actuator, constructed in accordance with the principles
 and teachings of the present invention is disclosed as being generally
 similar to the actuator disclosed within FIGS. 1 and 2 of the drawings, is
 generally indicated by the reference character 500, and component parts
 thereof which are similar to corresponding component parts of the actuator
 disclosed within FIGS. 1 and 2 have been designated by corresponding
 reference characters except that the reference characters noted in FIG. 5
 are in the 500 series.
 More particularly, the actuator 500 comprises an actuator body member 520,
 and the actuator body member 520 comprises a hub portion 522 which is
 adapted to be rotatably or pivotally disposed within a housing similar to
 housing l00 of the accelerator module disclosed within FIG. 1, and which
 is also adapted to be operatively connected to an accelerator pedal, not
 shown, of an electric vehicle, also not shown, through means of a
 connecting shaft or the like similar to shaft 60 of the accelerator module
 shown in FIG. 2. A torsion spring, similar to the torsion spring 170 of
 the accelerator module of FIG. 1, is adapted to be operatively associated
 with the hub portion 522 so as to bias the actuator 500 toward its normal
 position at which a distal end portion 524 of the actuator body member 520
 will normally engage a push-button element, similar to the push-button
 element 22 of a switch mechanism similar to the switch mechanism 20 of the
 accelerator module of FIG. 1, so as to maintain the switch mechanism in
 its normally-open state.
 A wiper member 540, comprising a pair of wiping elements 542,542, is
 fixedly mounted upon the distal end portion 524 of the actuator body
 member 520 such that the wiping elements 542,542 can engage constant and
 variable electrical resistance elements, similar to the constant and
 variable electrical resistance elements 32 and 34 of FIG. 1, which are
 mounted upon a corresponding printed circuit board similar to the printed
 circuit board 300 of FIG. 1. The basic mode of operation of the
 acceleration module of the present invention, and including the actuator
 500, is essentially the same as that disclosed within the aforenoted U.S.
 patent application Ser. No. 08/603,041, which mode of operation is hereby
 incorporated by reference, except as follows hereinafter with respect to
 the delayed closing of the normally-open switch mechanism and the
 corresponding delayed transmission of electrical power to the vehicle
 drive train as will now be discussed more fully in detail.
 With reference now being made to FIG. 3, it is seen that the distal end
 portion 524 of the actuator body member 520 is provided with a support
 bracket section 544 from which a pair of vertically spaced support arms
 546 project outwardly and transversely with respect thereto in a
 cantilevered manner. More particularly, each support arm 546 has a first
 proximal end which is integral with the bracket section 544 of the distal
 end portion 524 of the actuator body member 520, and a second distal end
 which is provided with a lip portion 548 for a purpose to be discussed
 hereinafter. As a result of the cantilevered structure of the support arms
 546,546, and the fabrication of the actuator 500 from a suitable
 thermoplastic material, each of the support arms 546,546 is resiliently
 flexible.
 With additional reference now being made to FIGS. 4 and 5, a spring-biased
 plunger or over-travel mechanism is adapted to be mounted upon the support
 arms 546,546 of the actuator 500 such that the plunger mechanism will be
 interposed between the distal end portion 524 of the actuator 500 and the
 push-button element of the normally-open switch of the accelerator module
 of the present invention, which normally-open switch is similar to the
 switch 20 shown in FIG. 1 of the drawings. More particularly, the plunger
 mechanism of the present invention is generally indicated by the reference
 character 550 and is seen to comprise a substantially H-shaped housing
 552.
 The housing 552 comprises a front wall portion 554 and a pair of oppositely
 disposed side walls 556,556 which are integral with the front wall portion
 554 and extend rearwardly therefrom. A pair of vertically spaced,
 transversely disposed rods or bars 558,558 are integral with the
 oppositely disposed side walls 556,556 and extend therebetween. The
 rearwardly disposed surface of front wall portion 554 is provided with an
 annular recessed portion 560, which is best seen in FIG. 5, and the
 annular recessed portion 560 in turn defines an annular, radially outer
 peripheral edge or lip 562 and an annular, radially inner boss section
 564. With particular reference again being made to FIG. 3, it is
 appreciated that the foregoing structure of the front wall portion 554 of
 the housing 552 serves to seat one end of a coil spring 566, while the
 opposite end of the coil spring 566 is seated around a circular boss
 portion 568 which is formed upon the bracket section 544 of the distal end
 portion 524 of the actuator body member 520 between the vertically spaced
 support arms 546,546.
 It is to be further appreciated that the plunger mechanism 550 is readily
 mounted upon the support arms 546,546 of the actuator body member 520 as a
 result of the transversely extending rods or bars 558,558 of the plunger
 mechanism 550 initially being engaged with the respective lip portions
 548,548 of the arms 546,546 whereby, due to the chamfered configurations
 of the lip portions 548,548 of the arms 546,546, as well as the aforenoted
 resilient flexibility of the arms 546,546, the arms 546,546 will in effect
 be compressed inwardly toward each other so as to permit the rods or bars
 558, 558 of the plunger mechanism 550 to in effect be snap-fitted over the
 lip portions 548,548 of the arms 546,546 whereupon the arms 546,546 can
 again expand outwardly so as to retain the plunger mechanism 550 thereon
 at the position shown in FIG. 3. The coil spring 566 of course serves to
 respectively bias and retain the plunger mechanism housing 552 toward and
 at the extended position shown in FIG. 3 with respect to the distal end
 portion 524 of the actuator body member 520 and the bracket section 544
 thereof when the actuator body member 520 has been rotated or pivoted in
 the clockwise direction, as indicated by the arrow CW, by means of the
 vehicle accelerator pedal linkage system, not shown, and after the plunger
 mechanism 550 has been disengaged from the push-button element of the
 normally-open switch mechanism so as to permit the normally-open switch
 mechanism to move to its CLOSED state and thereby provide electrical power
 to the vehicle drive train.
 In an opposite mode of operation, the plunger mechanism housing 552 is
 adapted to move toward the bracket section 544 of the distal end portion
 524 of the actuator body member 520, and against the bias of the coil
 spring 566, and attain or be disposed at the dotted line positions
 designated by 558', when the coil spring 566 is axially compressed as a
 result of the actuator body member 520 being rotated or pivoted in the
 counterclockwise direction, indicated by the arrow CCW, under the
 influence of the torsion spring, similar to the torsion spring 170 shown
 in FIG. 1, when the vehicle accelerator pedal is no longer depressed and
 after the front wall 554 of the plunger mechanism housing 552 has engaged
 the push-button element of the normally-open switch mechanism so as to
 move the normally-open switch mechanism from its CLOSED position or state
 back to its normally OPEN state. It is noted that the bracket section 544
 of the distal end portion 524 of the actuator body member 520 is provided
 with a pair of recessed regions 570,570 for accommodating the transversely
 disposed rods or bars 558,558 of the plunger mechanism housing 552 when
 the plunger mechanism 550 is engaged with the push-button element of the
 normally-open switch mechanism. It is to be further appreciated that when
 the plunger mechanism 550 is engaged with the normally-open switch
 mechanism under the influence of the torsion spring biasing the actuator
 500 in the counterclockwise direction CCW, the spring-biasing structure of
 the plunger mechanism housing 552 also serves to absorb shock or impact
 forces which would otherwise be deleteriously impressed upon the
 normally-open switch mechanism.
 The operation and significance of the spring-biased plunger mechanism 550
 of the present invention is submitted to be readily apparent, however, a
 brief description of such operation, and the significance thereof, will
 now be provided. It will be recalled that the objective of the present
 invention is to permit the actuator 500 to be initially moved a
 predetermined amount or angular extent in the clockwise direction CW, as a
 result of the depression of the vehicle accelerator pedal to which the
 actuator 500 is operatively connected in the aforenoted manner, prior to
 the closure of the switch mechanism and the transmission of electrical
 power to the electric vehicle drive train. Viewed from a different or
 opposite perspective, the transmission of electrical power to the vehicle
 drive train is to be effectively delayed until the actuator 500 has
 undergone a predetermined amount of rotational or pivotal displacement or
 movement corresponding to the depression of the vehicle accelerator pedal.
 In this manner, sudden "lurching" accelerations of the vehicle are
 effectively limited in their effect.
 Accordingly, when the actuator 500 of FIG. 3 is, in effect, inserted into
 the housing 100 and substituted for the actuator 220 of FIG. 1, and the
 actuator 500 is rotatably or pivotally moved in the counterclockwise
 direction CCW under the biasing influence of the torsion spring 170, such
 as, for example, when the vehicle accelerator pedal is not depressed or is
 released from a previously depressed state, the front wall portion 554 of
 the plunger or over-travel mechanism 550 will initially engage the
 push-button element 22 of the normally-open switch mechanism 20 and
 depress or actuate the same so as to in fact place the switch mechanism 20
 in its OPEN state.
 However, due to the biasing effect of the torsion spring 170 acting upon
 the actuator 500, the movable mounting of the plunger or over-travel
 mechanism housing 552 upon the support arms 546, 546 in a substantially
 linear or axial manner along the axis A as seen in FIG. 3, and the
 engagement of the front wall portion 554 of the plunger or over-travel
 mechanism 550 with the push-button element 22 of the normally-open switch
 mechanism 20, continued arcuate movement of the actuator 500, under the
 biasing influence of torsion spring 170 and in the counterclockwise
 direction CCW, causes continued movement of the plunger or over-travel
 mechanism housing 552 whereby the latter is moved from its extreme left
 extended position illustrated in FIG. 3 toward its extreme right depressed
 position, against the biasing force of its coil spring 566, such that the
 bars or rods 558,558 slide or move along the support arms 546, 546 of the
 actuator bracket section 544 and attain the dotted line positions
 558',558'. The push-button element 22 of the normally-open switch 20 of
 course remains engaged by the front wall portion 554 of the plunger or
 over-travel mechanism housing 552 and the normally-open switch 20
 correspondingly remains in its normally OPEN state.
 When the vehicle accelerator pedal is again depressed and the actuator 500
 is rotatably or pivotally moved in the clockwise direction CW, the distal
 end portion 524 of the actuator will undergo arcuate movement away from
 the normally-open switch mechanism 20, while at the same time, the plunger
 or over-travel mechanism housing 552 will begin to move, under the biasing
 influence of its coil spring 566, from its extreme right depressed
 position, at which the rods or bars thereof are shown at their dotted line
 positions 558',558', toward the extreme left extended position as
 illustrated in solid lines in FIG. 3. It will be appreciated, however,
 that at such time, or during such movement, the front wall portion 554 of
 the plunger or over-travel mechanism housing 552 is retained in its
 engaged state with the push-button element 22 of the normally-open switch
 mechanism 20 under the biasing influence of the coil spring 566 whereby
 the switch mechanism 20 is retained in its OPEN state. When, however, the
 vehicle accelerator pedal has been depressed further to a predetermined
 extent at which the actuator 500 attains a corresponding angular
 displacement position at which time the plunger or over-travel mechanism
 housing 552 has attained its fully extended position illustrated in FIG. 3
 and has just become disengaged from the push-button element 22 of the
 normally-open switch mechanism 20, the latter will attain its CLOSED state
 and electrical power will be transmitted to the vehicle drive train.
 Thus, it may be seen that in accordance with the teachings and principles
 of the present invention, as a result of the incorporation of the plunger
 or over-travel mechanism 550 within the switch actuation system of the
 vehicle accelerator module, the vehicle accelerator pedal is permitted to
 be depressed and undergo a predetermined amount of movement or
 displacement before electrical power is actually transmitted to the
 vehicle drive train. Considered from an opposite viewpoint, by
 incorporating the plunger or over-travel mechanism 550 within the switch
 actuation system of the electric vehicle accelerator module, the
 transmission of electrical power to the vehicle drive train is delayed a
 predetermined amount of time until the accelerator pedal has been
 depressed to a predetermined degree. In addition, the movable mounting of
 the plunger or over-travel mechanism 550 upon the actuator 500 under the
 biasing influence of the coil spring 566 serves to dampen or absorb any
 shock or impact forces which would otherwise be impressed upon the
 push-button element 22 of the normally-open switch mechanism 20, as well
 as upon the switch mechanism 20 per se and its mountings upon the printed
 circuit board 300, when the actuator 500 was returned to its normal
 position under the influence of the torsion spring 170 when the vehicle
 accelerator pedal was no longer depressed or released.
 Obviously, many variations and modifications of the present invention are
 possible in light of the above teachings. It is therefore to be understood
 that within the scope of the appended claims, the present invention may be
 practiced otherwise than as specifically described herein.