Abstract:
The invention relates to a manual control apparatus, such as a control pedal for a drive-by-wire control systems, and similar applications. According to an aspect of the invention, the manual control apparatus comprises a hysteresis mechanism that provides more precise and controllable hysteresis than previous mechanism. According to a further aspect of the invention, the manual control apparatus comprises an angular position sensor, and the angular position sensor may comprise abutments that reduce variation in the sensor. According to a still further aspect of the invention, the manual control apparatus comprises a stop pin that regulates the position of a rotatable member relative to the position sensor with less variation. The stop pin may also be used as a single fastener the holds the manual control apparatus together.

Description:
BACKGROUND 
     The invention relates to a manual control apparatus, such as a control pedal for drive-by-wire control systems, and similar applications. 
     Manual control apparatuses, such as throttle control pedals for drive-by-wire throttle control systems, are known in the art. Due to the fact that such pedals eliminate the mechanical linkage to the carburetor on an engine, hysteresis is often added to replicate the “feel” of a pedal having a mechanical linkage. In particular, it is desirable for a rotatable member, for example a pedal, to generate an increased resistance during depression, and an ability stay at a fixed position with reduced force in order to avoid operator fatigue. This is typically provided by introducing a deliberate amount of frictional resistance to movement at one or more locations in the pedal mechanism. A similar effect may also be desirable in other manual control apparatuses such as a hand operated throttle, or a brake control pedal for a drive-by-wire control system, without limitation. 
     Although manual control apparatuses having hysteresis are known in the art, a desirable apparatus would have more precisely controlled hysteresis than is presently available. In addition, a desirable apparatus would also be light in weight, simple in manufacture, and simple in assembly with as few components as possible. 
     In addition to hysteresis, manual control apparatuses typically have a rotation sensor that indicates rotation of the rotatable member, for example a pedal, relative to a fixed point, such as a base to which the pedal is mounted. Precise registration of the rotatable member relative to the fixed point at a particular angle is important for both calibration, and for repeatability from apparatus to apparatus. In a throttle control pedal, the angle of rotation of the pedal is typically measured from the idle position. However, tolerance stack-up can cause a significant variation within a group of apparatuses. Tolerance stack-up and manufacturing variation may also cause significant variation within the rotation sensor. Therefore, a desirable apparatus would provide reduced variation in the rotation sensor system. 
     SUMMARY 
     According to an aspect of the invention, a spring biases a rotatable member relative to a base, and the body of the spring is forced against a friction element. The friction element rides upon a curved friction surface and is directly coupled to the rotatable member. 
     According to a further aspect of the invention, a manual control apparatus is provided having an angular position sensor with a housing and a pivot mounted to the housing. A rotatable member is coupled to the pivot and the angular position sensor indicates an angular position of the rotatable member. A stop pin is mounted on the housing and the rotatable member rests on the stop pin when in the idle position. 
     According to a still further aspect of the invention, a manual control apparatus is provided having an angular position sensor comprising a housing mounted to a base. The housing is coupled to a pivot to sense rotation thereof. The housing comprises a first abutment that defines a first datum plane perpendicular to an axis of rotation of the pivot, and a second abutment that defines a second datum plane perpendicular to the axis of rotation. A rotor within the housing is coupled to the pivot shaft, and a sensing element cooperates with the rotor to indicate an angular position thereof relative to the base. The sensing element rests upon the first abutment, and a rotor spring biases the rotor against the second abutment. 
     According to a still further aspect of the invention, a manual control apparatus is provided, comprising an angular position sensor comprising a housing coupled to a pivot to sense rotation thereof. The housing comprises a pair of opposing bosses that are received within recesses in a base. An idle stop is mounted to the housing and the base thereby retaining the bosses within the recesses. The housing is restrained within the base using the idle stop as a single fastener. 
     The manual control apparatus of the invention is particularly well suited for use with a drive-by-wire system wherein a direct mechanical linkage to an engine throttle or brake hydraulic system, for example, is eliminated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 presents a side cross-section view of a manual control apparatus according to an aspect of the invention, taken along line  1 — 1  of FIG.  2 . 
     FIG. 2 is a front view of a manual control apparatus according to an aspect of the invention. 
     FIG. 3 is a side cross-sectional view of a manual control apparatus according to a further aspect of the invention, taken along line  3 — 3  of FIG.  4 . 
     FIG. 4 is a front view of a manual control apparatus according to an aspect of the invention. 
     FIG. 5 is a side cross-sectional view of a manual control apparatus according to a further aspect of the invention. 
     FIG. 6 is a side cross-sectional view of a manual control apparatus according to a further aspect of the invention. 
     FIG. 7 is a side cross-sectional view of a manual control apparatus according to a further aspect of the invention. 
     FIG. 8 is a side cross-sectional view of a manual control apparatus according to a further aspect of the invention. 
     FIG. 9 is a side view of a throttle control pedal according to a further aspect of the invention. 
     FIG. 10 is a front view of the FIG. 9 throttle control pedal. 
     FIG. 11 is an enlarged front view of an upper portion of the FIG. 9 throttle control pedal with partial cross-sections. 
     FIG. 12 is an enlarged side view of an upper portion of the FIG. 9 throttle control pedal with partial cross-sections taken along line  12 — 12  of FIG.  10 . 
     FIG. 13 is a perspective view of a spring according to an aspect of the invention. 
     FIG. 14 is a top plan view of the FIG. 13 spring. 
     FIG. 15 is a top plan view of friction element according to an aspect of the invention. 
     FIG. 16 is a side elevational view of the FIG. 15 friction element. 
     FIG. 17 is a perspective view of the FIG. 15 friction element. 
     FIG. 18 is an exploded perspective view of a housing according to an aspect of the invention. 
     FIG. 19 is a perspective view of a base that is employed with the housing of FIG.  18 . 
     FIG. 20 is a perspective view of the backside of an upper portion of the FIG. 9 throttle control assembly. 
    
    
     DETAILED DESCRIPTION 
     Various aspects of the invention are presented in FIGS. 1-18, which are not drawn to scale, and wherein like components in the numerous views are numbered alike. As used herein, the term “manual” refers to operation by hand, foot, or any other body part. Referring now specifically to FIGS. 1 and 2, a manual control apparatus  10  with hysteresis is presented according to one aspect of the invention, in this example a throttle control pedal. FIG. 2 is a front view of the pedal, and FIG. 1 is a cross-sectional side view taken along line  1 — 1  of FIG.  2 . The throttle control pedal  10  is shown mounted to a suitable structure of a motorized vehicle, such as a passenger compartment firewall  21 . 
     The throttle control pedal  10  comprises a base  12  having a curved friction surface  14 . A pivot  16  is mounted to the base  12 , which defines an axis of rotation  18  spaced from the curved friction surface  14 , as indicated at  20 . A rotatable member  22 , in this example a lever, is mounted to the pivot  16 , wherein the rotatable member  22  is rotatable around the axis of rotation  18  relative to the base  12 . A friction element  24  is mounted to rotate with the rotatable member  22 , spaced from the axis of rotation  18 , and forcible against the curved friction surface  14 . 
     The friction element  24  is directly coupled to the rotatable member  22 . As used herein, the term “directly coupled” means that the friction element is mechanically linked (as opposed to frictional coupling alone) to the rotatable member for rotation therewith so that the two rotate in unison. This is in contrast to certain prior art hysteresis mechanisms that implement only frictional coupling with the spring to induce movement of the friction element. The present invention offers a distinct advantage in that the friction element is directly forced to move with the rotatable member  22  rather than relying solely upon the presence of sufficient frictional force at the spring/friction element interface to move the friction element. 
     The rotatable member is biased by a spring  26  having a first end  28 , a second end  32 , and an intermediate portion  30  between the first end  28  and the second end  32 . The first end  28  is coupled to the base  12 , and the second end  32  is coupled to the rotatable member  22 . Rotation of the rotatable member  22 , as indicated by arrow  34 , forces the intermediate portion  30  against the friction element  24 , as indicated by arrow  36 , resisted by the curved friction surface  14 , as indicated by the opposing arrow  38 , thereby generating a frictional resistance to the rotation. At least two springs  26 , two friction elements  24 , and two cylindrical friction surfaces  14  are preferably provided for redundancy. 
     The pivot  16  comprises a shaft  40  received whithin a bearing  42 . The bearing  42  is mounted to the base  12  and the shaft  40  is fixed to the rotatable member  22 . The bearing  42  may be any type of bearing suitable for use in a throttle control pedal including, without limitation, bushings, ball bearings, needle bearings, and roller bearings. 
     The base  12  may configured in a variety of ways. For example, the base  12  may comprise a bottom panel  11  and two side flanges  13  extending upward from the bottom panel  11 . A stop pin  15  may be attached to the base  12  that performs multiple functions. First, the first end  28  of the spring  26  rests against it, thus restraining the first end  28  against rotation. Second, the stop pin  15  acts as an idle stop for the rotatable member  22 . As will be described more fully, the stop pin may also be used to provide accurate registration of the rotatable member  22  relative to a with a position sensor with less variation, and it may also be used as a single fastener that assembles the manual control apparatus  10 . 
     The rotatable member  22  may comprise a finger  23  that engages the stop pin  15  at the idle position thus preventing further rotation. The second end  32  may be fixed to the rotatable member  22  by a second pin  17 . The friction element  24  may be fixed to the rotatable member  22  by a third pin  19  that allows the friction element to rotate relative to the rotatable member  22 . The pin connection causes essentially all of the load  34  induced by the intermediate portion  30  to be transferred to the cylindrical friction surface  14 , although this is not strictly necessary in the practice of the invention as long as a substantial portion of the load  34  is transferred. A foot rest  25  may be pivotally mounted to the end of the rotatable member  22 , and may be spring biased against the rotatable member  22  if desired. Numerous variations in such minutia are possible and evident in light of the description provided herein. 
     Referring now to FIGS. 3 and 4, an angular position sensor  44  may be mounted to the base  12  that senses angular position of the shaft  40 . FIG. 4 is a front view of the upper portion of the throttle control pedal  10 , and FIG. 3 is a side cross-sectional view taken along line  3 — 3  of FIG.  4 . The various components of the throttle control pedal  10  are the same as presented in FIGS. 1 and 2, and numbering is not repeated here for the sake of clarity, unless needed for reference. Various angular position sensors may be employed in the practice of the invention. In the example presented, the angular position sensor  44  comprises a rotor  46  fixed to the shaft  40 . In FIG. 3, the rotatable member  22  is shown in phantom for reference purposes. 
     In the example presented, the angular position sensor  44  is a simple potentiometer. The position sensor  44  further comprises a housing  45  that encloses the rotor  46 , and an opposing pair of conductive paths  47  and  51 . The rotor  46  is provided with a pair of spring biased electrical brushes  53  electrically clamped to each other by a shunt  49 . The brushes  53  and shunt  49  provide a conductive path in combination with the conductive traces  47  and  51 . Rotating the rotatable member  22  rotates the rotor  46  which increases the length of the conductive path, and hence the resistance in proportion to the rotation of the rotatable member  22 . 
     A pair of conductive feed-throughs  55  are provided that may be connected to a wiring harness and appropriate electronics for converting the resistance reading to an indication of angular position. Variations are possible, and numerous suitable position sensors  44  are well known in the art. It is not intended to restrict the invention to the simple potentiometer embodiment presented herein. For example, U.S. Pat. No. 5,133,321 to Hering et al. discloses an integrated position and idle control sensor for drive-by-wire pedal assemblies, which is incorporated herein by reference. 
     The friction element  24  of FIGS. 1 and 2 is configured as a shoe. It does not encircle the cylindrical friction surface  14 . However, the friction element may be configured in other shapes. As presented in FIG. 5, a friction element  48  is presented that is configured as a ring the encircles the curved friction surface  14 . Similarly, the curved friction surface  14  may be fully cylindrical about the axis of rotation  18 , as shown in FIG. 5, or may be just a sector of a cylinder. 
     Referring now to FIG. 6, another embodiment is presented that implements a friction element  50 , wherein the spring  26  is a torsional spring encircling the axis of rotation  18 . The curved friction surface  14  is a cylindrical surface concentric about the axis of rotation  18 . The friction element  50  is a ring encircling the curved friction surface  14  and comprises a protuberance  54  having a channel  52  that receives the second end  32  of the spring  26 . 
     Referring now to FIG. 7, a preferred embodiment is presented that implements the friction element  50 , wherein the spring  26  is a torsional spring encircling the friction element  50 . The torsional spring is spaced from the friction element  50  except at the intermediate portion  30 , wherein the intermediate portion  30  rests upon the friction element  50  supported by the curved friction surface  14 . The spring  26  is stressed when the throttle control pedal  10  is assembled such that a preload is exerted upon the friction element  50  at the intermediate portion  30  toward the axis of rotation  18  when the rotatable member  22  is in the idle position, as shown. The spring  26  is eccentrically offset relative to the friction element  50  when installed on the base  12 . 
     The inside diameter of the friction element  50  is larger than the outside diameter of the curved friction surface  14  such that a space  58  is defined therebetween, except that the spring preload deflects the friction element  50  only beneath the intermediate portion  30  of the spring  26  such that it is forced into contact with the curved friction surface  14  beneath the intermediate portion  30 . In practice, the inside diameter of the friction element  50  needs to be only slightly larger than the diameter of the curved friction surface such that a frictional resistance to rotation is generated essentially beneath the intermediate portion  30 , and not along the entire circumference of the friction surface  14 . 
     This feature, in combination with the spring  26  being spaced from the outside diameter of the friction element  50 , except at the intermediate portion  30 , generates an essentially pure side load during stroking of the rotatable member  22  directed toward the axis of rotation  18 . In such manner, the location where the friction element  50  generates the frictional resistance to rotation and the magnitude of the frictional resistance are precisely controlled. 
     According to a further aspect of the invention, a method of applying hystersis to a manual control apparatus is provided, comprising forcing an intermediate portion  30  of a spring  26  against a friction element  24  resting on a curved friction surface  14  that is part of a base  12  by rotating a rotatable member  22  about an axis of rotation  18  and rotating a second end  32  of the spring  26  with the pedal lever, a first end  28  of the spring  26  being coupled to the base  12 , the rotatable member  22  being mounted to the base  12  and the friction element being directly coupled to the rotatable member  22 . 
     Referring now to FIG. 8, an embodiment is presented identical to FIG. 7, except that the torsional spring  26  is replaced by a linear spring  60  having a first end  62 , and intermediate portion  64 , and a second end  66 . The spring  60  and the intermediate portion  64  function in the same manner previously described in relation to FIG. 7 to provide a side load on the friction element  56 , and to resist depression of the rotatable member  22 . In this example, friction element  56  comprises a protuberance and pin passing through the protuberance and attached to the rotatable member  22 , which directly couples the friction element  56  and the rotatable member  22 . Although described with respect to particular embodiments, the concepts described in relation to FIGS. 7 and 8 may be implemented in the other embodiments described herein. 
     Although described in relation to a rotatable member  22  that is a lever with reference to FIGS. 1-8, any manually rotatable member may be implemented in the practice of the invention with any control apparatus such as a throttle control, a brake control, or other manual control adaptable for use with the invention, without limitation. 
     Referring now to FIGS. 9 and 10, side and front views, respectively, of a throttle control pedal  100  with hysteresis are presented according to a further aspect of the invention. FIG. 11 presents an enlarged view of the upper portion of FIG. 9 with partial cross-sections of selected portions. The throttle control pedal  100  is shown mounted to a suitable structure of a motorized vehicle, such as a passenger compartment firewall  121 . 
     Referring to FIGS. 9-11, The throttle control pedal  100  comprises a base  112  comprising a frame  111  and a housing  113  The housing  113  has a curved friction surface  114 , as shown in FIG.  11 . As used herein, the term “base” is intended to mean a non-rotating structure to which the lever is coupled, and any non-rotating structure mounted to the base. Thus, the housing  113  and frame  111  are both members of the base  112 . 
     A pivot  116  is mounted to the base  112  that defines an axis of rotation  118  spaced from the curved friction surface  114 . The curved friction surface  114  is cylindrical about the axis of rotation  118 , and the pivot  116  comprises a shaft  140  received within a bearing  142  mounted to the housing  113 . A lever  122  is fixed to the shaft  140 . A foot rest  121  is pivotally attached to the lever  122 . A friction ring  150  is mounted to rotate with the lever  122 , spaced from the axis of rotation  118 , encircling the curved friction surface  114  and forcible against the curved friction surface  114 . 
     A torsional spring  126  encircles the friction ring  150 . The torsional spring has a first end  128 , a second end  132 , and an intermediate portion  130  between the first end  128  and the second end  132 . The first end  128  is fixed to the base  112  and the second end  132  is fixed to the lever  122 . Rotation of the lever  122  forces the intermediate portion  130  against the friction ring  150  resisted by the curved friction surface  114  thereby generating a frictional resistance to the rotation through the friction ring  150 . Thus, the principle of operation of throttle control pedal  100  is identical to that of the throttle control pedal  10  of FIGS. 1 and 2. 
     As previously described in relation to FIG. 7, a small space  158  is defined between the friction ring  150  and the curved friction surface  114 , except beneath the intermediate portion  130  of the spring  126  where the friction ring  150  rests upon the curved friction surface  114  due to preload in the spring  126 . 
     A stop pin  115  is mounted to the base  112  and the lever  122  is provided with a finger  123  that engages the stop pin  115  in the idle position. The lever  122  also comprises a cross bar  117  that engages the second end  132  of the spring  126 . The base  12  also comprises a lower stop  120  that stops further pivoting of the lever  122  at full depression. 
     Referring now to FIG. 12, a side cross-sectional view of the upper part of the throttle control pedal  100  through the housing  113  taken along line  12 — 12  of FIG. 10 is presented. The friction ring  150  comprises an outside cylindrical surface  151  and a protuberance  152  extending therefrom. The protuberance  152  has a channel  154  that receives the second end  132  of spring  126 . The cross bar  117  is shown for reference, and preferably rides on the protuberance  152 . Preferably, the protuberance  152  and cross bar  117  rotate concentric with the axis of rotation  118  so that the cross bar  117  does not slide on the surface of the protuberance while the lever  122  is depressed. 
     Referring now to FIG. 13, a perspective view of a spring  127  that may be used in the practice of the invention is presented. Spring  127  comprises a first end  129 , an intermediate portion  131 , and a second end  133 , and is identical to spring  126  except the first end  129  is shorter than the first end  128  of spring  126 . Such variations may be made for particular applications without departing from the invention. Referring now to FIG. 13, a top plan view of the spring  127  is presented in an unstressed state. The spring  127  is preloaded when installed with the pedal  122  in the idle position, as indicated by the phantom position  134  of the second spring end  133 . Full load is indicated by phantom position  136  of the second spring end  133 . 
     Referring now to FIGS. 15,  16  and  17 , a top plan view, a side elevational view, and a perspective view, respectively, are presented of a friction element  160  configured as a ring according to a further aspect of the invention. The friction element  160  comprises an outside surface  161 , and a protuberance  162  extending from the outside cylindrical surface  161  having a channel  164  that receives a spring end, as previously described herein. According to a further aspect of the invention, the outside cylindrical surface  161  comprises a spacer  166  having a predetermined thickness  168  above the surface  161 , and the protuberance  162  extends from the spacer  166 . The protuberance  162  and the spacer  166  couple the torsional spring  126  or  127  (shown in phantom) relative to the friction ring or element  160  such that in an unstressed state a space is defined between the torsional spring and the friction ring encircling the friction ring and interrupted by the spacer. The second end  132  or  133  (shown in phantom) is received within the channel  164 . The friction element  160  may also comprise a rim  170  extending outwardly from the outside cylindrical surface  161 . Upon installing the friction element  160  and spring assembly into a pedal assembly  10  at an idle position, preloads the spring, and causes the intermediate portion of the spring to be forced into contact with the friction ring  160 , as previously described, thus interrupting the space  172  at another location. 
     Referring now to FIG. 18, an exploded perspective view of the housing  113  is presented, along with components attached to the housing  113 . The housing  113  includes an angular position sensor  144  that is coupled to the pivot to sense rotation thereof. In the example presented, the angular position sensor comprises a rotor  146  coupled to the shaft  140 , and a sensing element  147  fixed to the housing. Terminals  149  are provided that mate with the sensing element, and that are connected to an external electrical connector  170  for connection to a wire harness. An internal spring  200  and an O-ring may  202  may also be provided. 
     The housing  113  comprises a first abutment  172  that defines a first datum plane perpendicular to the axis of rotation  118  and a second abutment  174  that defines a second datum plane perpendicular to the axis of rotation  118 . The pivot shaft is received within an opening  176  in the housing  45 . The sensing element  147  cooperates with the rotor  146  to indicate an angular position thereof relative to the base  112 . 
     The sensing element  147  rests upon the first abutment  172  and a rotor spring  178  biases the rotor  146  against the second abutment  174 . Thus, the sensing element  147  and the rotor  146  are accurately positioned relative to each other, and the positioning is not dependent accuracy in joining the first and second halves of the housing  113 . 
     In the example presented, the first and second abutments  172  and  174  are curved ridges molded in the left half of the housing  113 . One or more further structures may be added, such as a nipple  180  that position the sensing element  147  within the first datum plane. If the axis of rotation  118  is viewed as a Z-axis, then the X and Y axes lie in the first datum plane, as determined by the first abutment  172 , and the nipples  180  position the sensing element relative to the X and Y axes. Thus, the sensing element  180  may be accurately positioned in all three spatial dimensions relative to the rotor  146 . Innumerable variations are possible in light of the description provided herein. 
     In the example presented, the rotor spring  178  comprises at least one tab  182  that is integral with the rotor  146 . Two opposing tabs  182  are preferably provided. The tab  182  bears against the right half of housing  113  and biases the rotor  146  against the second abutment  174 . The tab  182  may be provided with a spherical bump  184  that focuses the spring load onto a predefined area of the housing  113 . The housing  113  may also comprise a third abutment, the backside of which indicated at  186 , that the rotor spring  178  bears against. In the example presented, the third abutment  186  is a curved ridge and serves as a track upon which the spherical bump  184  rides. Innumerable variations are possible in light of the description provided herein. 
     Referring now to FIG. 19, a perspective view of the base  112  is provided. According to a further aspect of the invention, the base  112  comprises a pair of recesses  188 . The housing  113  comprises a pair of opposing bosses  190  (FIG. 18) that are received within the recesses  188 . The stop pin  115  couples the housing to the base thereby retaining the bosses  190  within the recesses  188 . The housing  113  is provided with a stop pin hole  124  tht receives the stop pin  115 . 
     This is further illustrated in FIG. 20 wherein a perspective view is presented of the backside of the upper portion of the throttle control pedal  100  of FIG.  9 . The bosses  190  closely conform to the recesses  188 , which open in the same direction. The stop pin  115  is located on a side opposite from that direction. In the embodiment presented, the recesses  188  are C-shaped and formed in a pair of side flanges  192  that extend upward from a bottom panel  194 , and the bosses  190  are cylindrical. The housing  113  is captive in all directions within the bracket  112 . The stop pin  115  serves as a single fastener that holds the assembly together. 
     As presented in FIGS. 18,  19 , and  20 , the recesses  188  are provided with slots  196 , and the bosses  190  are provided with ears  198  that are received within the slots  196 . The slots  196  and ears  198  assist in assembly. During assembly, the bosses  190  are slid into the recesses  188  with a rotation that presses the ears  198  into the slots. This movement rotates the stop pin hole  124  toward the bottom panel  196  of the base  112  until it aligns with the stop pin  115 , after which the stop pin is inserted into the stop pin hole  124 . According to a preferred embodiment, approximately 50% of the force applied to the pedal during depression is resisted by hysteresis, the balance by the springs. The base is formed from metal, cast or stamped, and is covered with a coating having good dry lubricating properties, such as zinc dichromate or epoxy paint. The bearings are self lubricating and are press fit into the housing. Porous metal or plastic bearings impregnated with oil are desirable. The housing may be formed from a reinforced plastic, injected molded, such as a 30% glass filled polyester. The friction elements may be formed from plastic, such as polyacetol or a fluorpolymer, preferably unreinforced by fiber. The rotor may be formed from plastic and is preferably integrally molded onto the shaft. The sensing element is preferably a ceramic resistance element. 
     Two biasing/hysteresis springs are preferably provided. The hysteresis force is directly generated by the springs, so that if a spring breaks, the spring ceases to generate hysteresis. Thus, the total hysteresis is always proportional to the spring force. 
     According to a further aspect of the invention, with reference to FIGS. 1-20 and the description provided herein with respect to those figures, a manual control apparatus is provided, comprising: 
     a base; 
     a pivot mounted to said base that defines an axis of rotation spaced from said curved friction surface; 
     a rotatable member coupled to said pivot, wherein said rotatable member is rotatable around said axis of rotation relative to said base; 
     an angular position sensor comprising a housing fixed to said base and coupled to said pivot to sense rotation thereof; 
     a stop fixed to said housing; and, 
     a spring coupled to said rotatable member and said base, said spring biasing said rotatable member against said stop. 
     According to a further aspect of the invention, a manual control apparatus is provided, comprising: 
     a base comprising a pair of recesses; 
     a pivot mounted to said base that defines an axis of rotation; 
     a rotatable member coupled to said pivot, wherein said rotatable member is rotatable around said axis of rotation relative to said base; 
     an angular position sensor comprising a housing coupled to said pivot to sense rotation thereof, said housing comprising a pair of opposing bosses that are received within said recesses; 
     a stop coupled to said housing and said base thereby retaining said bosses within said recesses; and, 
     a spring coupled to said rotatable member and said base, said spring biasing said rotatable member against said stop. 
     According to a further aspect of the invention, a manually operable throttle control is provided, comprising: 
     a base; 
     a manually operable control lever for controlling a throttle position; 
     an electrical sensor for sensing the angular position of said lever and for outputting an electrical signal related to said lever position; 
     a shaft rotatably mounted on said base and drivingly connecting said lever with said sensor, said sensor and said shaft being relatively rotatable; 
     a pin securing said sensor on said base and fixing the rotational position of said sensor relative to said shaft and said lever. 
     Said pin may include a portion forming stop engagable by said lever to limit the rotation of said lever, and said lever includes a surface engagable with said stop portion of said pin. 
     Said base may include a pair of spaced apart flanges, said sensor may includes a through-hole therein, and said pin passes through said through-hole and is secured to said flanges. 
     Said pin may include an extension on one end thereof extending outwardly beyond one of said flanges, and said stop portion is defined on said pin extension. 
     At least one torsion spring may be wrapped around said drive shaft, said spring having a free end engaging pin whereby to restrain said spring against rotation about said drive shaft. 
     According to a further aspect of the invention, a manually operable throttle control is provided, comprising: 
     a base; 
     a manually operable control lever displaceable for controlling a throttle position; 
     an electrical sensor for sensing the displacement position of said lever and for outputting an electrical signal related to said lever position; 
     a shaft carried on said base and connecting said lever with said sensor; and, 
     a locating pin carried on said base for locating the rotational position of said sensor relative to said displacement position of said lever. 
     Although the invention has been described and illustrated with reference to specific illustrative embodiments thereof, it is not intended that the invention be limited to those illustrative embodiments. Those skilled in the art will recognize that variations and modifications can be made without departing from the true scope and spirit of the invention as defined by the claims that follow. It is therefore intended to include within the invention all such variations and modifications as fall within the scope of the appended claims and equivalents thereof.