Abstract:
An excentric pin for an electronic throttle control assembly, which is used to adjust the default position of at least one spring used to control the position of a valve plate, where the valve plate is located in an opening of a housing in the electronic control assembly. The excentric pin is used to adjust the default angle of the valve plate to have an angular tolerance of +/−0.10°. The excentric pin is slideably pressed into an aperture of the housing of the electronic throttle control assembly, and turned using some type of driver. The electronic throttle control assembly may be a one-spring design, or a two-spring design, where the two-spring design requires only one spring pin and the excentric pin. Also, the excenter pin may be used to adjust the position of the sector gear, e.g., function as the lower mechanical stop to provide a minimum opening angle for low leakage, and a minimum opening angle to avoid throttle plate corking into opening of the housing.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 62/259,952 filed Nov. 25, 2015. The disclosure of the above application is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates generally to an excentric pin used for adjusting the position of at least one spring in an electronic throttle control assembly to adjust the default flow position of a throttle plate. 
       BACKGROUND OF THE INVENTION 
       [0003]    Electronic throttle bodies are generally known, and are used for controlling the flow of air into an engine. These throttle bodies have some type of valve, which is typically a valve plate disposed in a port of a housing, which is rotated to increase or decrease the amount of air flow into the engine. Electronic throttle bodies typically have a “default air flow” setting, which is achieved by setting a specific opening angle of the throttle plate relative to its fully closed position. A final gear (such as a sector gear), is mounted on a shaft along with the throttle plate, and the sector gear is used to rotate the shaft and throttle plate. 
         [0004]    The default air flow is achieved by including the use of an opening spring connected to the sector gear, where the opening spring is supported by a spring stop inside the sector gear and a default stop located in the housing. Many design requirements include specifying the tolerance of the opening angle of the valve plate to be ±0.1°, and in some instances, less than ±0.1°. 
         [0005]    During assembly, the sector gear is mounted to the shaft, the throttle plate is in a fully closed position, and the sector gear is positioned such that the opening spring places the gear against a gear stop. Positioning the valve plate to have the desired default air flow setting requires a significant amount of effort. 
         [0006]    One of the solutions to provide proper adjustment of the valve plate is to use set screws, either to set the default stop position of the valve plate or the gear stop position. However, using set screws has the disadvantage that the screw diameter must be larger than the end of the spring, and large enough to guaranty the proper connection to the appropriate component attached to the throttle body. This results in the diameter of these set screws being too large to position them properly inside the gearbox. Therefore, the screws must be driven for rotation from outside of the gearbox. After assembly, the set screws must be secured and the access holes for the set screws must be closed off to ensure the set screws remain properly positioned and cannot be manipulated. 
         [0007]    Accordingly, there exists a need for a throttle body which incorporates the ability to adjust the default air flow setting of the valve plate, without the drawbacks mentioned above. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention is an excentric pin for an electronic throttle control assembly, where the pin is used to adjust the position of at least one spring, to therefore adjust the default flow position of a valve plate, where the valve plate is located in an opening of a housing in the electronic control assembly. The excentric pin is used to adjust the default air flow by adjusting the default angle of the valve plate with an angular tolerance of +/−0.10°, which essentially reduces the tolerance during assembly by a factor of 3.5 due to the ability to adjust the cam position of the excentric pin, and the position of the end of the spring resting against the cam. 
         [0009]    The excentric pin is slideably pressed into an aperture of the housing of the electronic throttle control assembly. The excentric pin is turned using some type of driver. In one embodiment, the driver has multiple external splines, where the excentric pin is located in an aperture of the housing, and secured against rotation after adjustment to the desired position. 
         [0010]    In one embodiment, the electronic throttle control assembly is a one-spring design, and in another embodiment, the electronic control assembly is a two-spring design, where the two-spring design requires only one excentric pin. The two-spring design uses the excentric pin to adjust the end of each of the springs, and thus angle of the valve plate and airflow associated with the limp-home mode. With the one-spring design, the excentric pin is used to reduce or eliminate the endplay of each end of spring, and/or to set the angle and air flow. 
         [0011]    In one embodiment, the excentric pin has an external drive portion used to adjust the position of the pin. In another embodiment, the excentric pin includes an excenter, and in yet another embodiment, the excentric pin includes press-zone, which may have a ribbed, threaded, or knurled surface. 
         [0012]    Also, the excenter pin may be used to adjust the position of the sector gear, e.g., function as the lower mechanical stop to provide a minimum opening angle for low leakage, and a minimum opening angle to avoid throttle plate corking in the air channel. 
         [0013]    In one embodiment, the present invention is a throttle control assembly, which includes a housing, a central port formed as part of the housing, a valve plate mounted on a shaft such that the valve plate is disposed in the central port, a gear assembly which includes a sector gear mounted on a shaft, and an actuator that is engaged with the gear assembly. A mounting aperture is integrally formed as part of the housing, and at least one adjustment pin is disposed in the mounting aperture. The throttle control assembly also includes an opening spring having a first end in contact with the at least one adjustment pin, and a second end engaged with the sector gear, and a closing spring having a first end adjacent the first end of the opening spring, and a second end engaged with the housing. The adjustment pin includes a main body, and a cam integrally formed with the main body such that the cam is in contact with the first end of the opening spring. A drive portion is integrally formed with the main body adjacent the cam, and the drive portion of the adjustment pin is rotated such that the cam changes the position of the opening spring and the closing spring, to adjust the position of the sector gear and the valve plate. 
         [0014]    The adjustment pin also includes a knurled portion formed as part of the main body adjacent the cam, and a press-zone portion integrally formed as part of the main body adjacent the knurled portion. During assembly, the press-zone portion is pressed into the mounting aperture, and after the adjustment pin is rotated to change the position of the first end of the opening spring and the first end of the closing spring, the adjustment pin is further pressed into the mounting aperture such that the knurled portion is pressed into the mounting aperture, fixedly mounting the adjustment pin in the mounting aperture. 
         [0015]    In an alternate embodiment, a ribbed portion is formed as part of the main body adjacent the cam instead of the knurled portion, and the ribbed portion is inserted into the mounting aperture formed as part of the housing to fixedly mount the adjustment pin to the housing. 
         [0016]    The drive portion may be an external drive portion having a plurality of external splines, or an internal drive portion having a plurality of internal splines. 
         [0017]    In another alternate embodiment, instead of the cam, different size bearing may be chosen and mounted to the pin, where the diameter of the bearing chosen corresponds to the desired location of the spring. 
         [0018]    In another alternate embodiment, a second adjustment pin is fixedly mounted to the housing adjacent the sector gear and in contact with a gear stop integrally formed as part of the sector gear. The second adjustment pin is positioned to adjust the position of the gear and the default flow position of the valve plate. 
         [0019]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
           [0021]      FIG. 1  is a perspective view of a throttle control assembly, according to embodiments of the present invention; 
           [0022]      FIG. 2  is a perspective view of a throttle control assembly, with the cover removed, according to embodiments of the present invention; 
           [0023]      FIG. 3  side view of a portion of a housing, used as part of a throttle control assembly, according to embodiments of the present invention; 
           [0024]      FIG. 4  is a perspective view of a sector gear with an opening spring and a closing spring attached to the sector gear, used as part of a throttle control assembly, according to embodiments of the present invention; 
           [0025]      FIG. 5  is an exploded view of several components which are part a throttle control assembly, according to embodiments of the present invention; 
           [0026]      FIG. 6A  is a first perspective view of first embodiment of an excenter pin used as part of a throttle control assembly, according to embodiments of the present invention; 
           [0027]      FIG. 6B  is a second perspective view of first embodiment of an excenter pin used as part of a throttle control assembly, according to embodiments of the present invention; 
           [0028]      FIG. 6C  is a third perspective view of first embodiment of an excenter pin used as part of a throttle control assembly, according to embodiments of the present invention; 
           [0029]      FIG. 6D  is a front view of a first embodiment of an excenter pin used as part of a throttle control assembly, according to embodiments of the present invention; 
           [0030]      FIG. 6E  is a side view of a first embodiment of an excenter pin used as part of a throttle control assembly, according to embodiments of the present invention; 
           [0031]      FIG. 6F  is a rear view of a first embodiment of an excenter pin used as part of a throttle control assembly, according to embodiments of the present invention; 
           [0032]      FIG. 7A  is a side view of a throttle control assembly, with the cover removed and the excenter pin in a first position, according to embodiments of the present invention; 
           [0033]      FIG. 7B  is an enlarged view of a circled portion shown in  FIG. 7A ; 
           [0034]      FIG. 7C  is a side view of part of a throttle control assembly, with the cover removed and the excenter pin in a second position, according to embodiments of the present invention; 
           [0035]      FIG. 7D  is an enlarged view of a circled portion shown in  FIG. 7C ; 
           [0036]      FIG. 8A  is a side view of another embodiment of a throttle control assembly having an additional excenter pin, with the cover removed, according to embodiments of the present invention; 
           [0037]      FIG. 8B  is an enlarged view of a circled portion shown in  FIG. 8A ; 
           [0038]      FIG. 9A  is a first perspective view of a second embodiment of an excenter pin used as part of a throttle control assembly, according to embodiments of the present invention; 
           [0039]      FIG. 9B  is a second perspective view of a second embodiment of an excenter pin used as part of a throttle control assembly, according to embodiments of the present invention; 
           [0040]      FIG. 10A  is a first perspective view of a third embodiment of an excenter pin used as part of a throttle control assembly, according to embodiments of the present invention; 
           [0041]      FIG. 10B  is a second perspective view of a third embodiment of an excenter pin used as part of a throttle control assembly, according to embodiments of the present invention; 
           [0042]      FIG. 11A  is a variation of the embodiment of the excenter pin shown in  FIGS. 6A-6F , with the knurled portion removed, according to embodiments of the present invention; 
           [0043]      FIG. 11B  is a variation of the embodiment of the excenter pin shown in  FIGS. 9A-9B , with the knurled portion removed, according to embodiments of the present invention; 
           [0044]      FIG. 11C  is a variation of the embodiment of the excenter pin shown in  FIGS. 10A-10B , with the knurled portion removed, according to embodiments of the present invention; 
           [0045]      FIG. 12A  is a variation of the embodiment of the excenter pin shown in  FIGS. 6A-6F , which includes a ribbed portion instead of the knurled portion, according to embodiments of the present invention; 
           [0046]      FIG. 12B  is a variation of the embodiment of the excenter pin shown in  FIGS. 9A-9B , which includes a ribbed portion instead of the knurled portion, according to embodiments of the present invention; 
           [0047]      FIG. 12C  is a variation of the embodiment of the excenter pin shown in  FIGS. 10A-10B , which includes a ribbed portion instead of the knurled portion, according to embodiments of the present invention; 
           [0048]      FIG. 13A  is a perspective view of another embodiment of an excenter pin, having a full cam, according to embodiments of the present invention; 
           [0049]      FIG. 13B  is a rear view of another embodiment of an excenter pin, having a full cam, according to embodiments of the present invention; and 
           [0050]      FIG. 14  is an enlarged side view of a throttle control assembly, with the cover removed and another alternate embodiment of an excenter pin incorporating a bushing, according to embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0051]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
         [0052]    A throttle control assembly according to the present invention is shown in the Figures generally at  10 . The assembly  10  includes a housing  12 , and formed as part of the housing  12  is a central port  14 , through which air passes during operation of the assembly  10 . Disposed in the central port  14  is a shaft  16 , which is rotatable. The shaft  16  includes a slot  18 , and disposed in the slot  18  is a valve member, which in this embodiment is a valve plate  20 . The valve plate  20  includes two apertures, which are in alignment with two threaded apertures formed as part of the shaft  16 . Connecting the plate  20  to the shaft  16  is a fastener, which in this embodiment is a threaded screw  26 , which is inserted through the apertures of the plate  20  and the threaded apertures of the shaft  16 , securing the valve plate  20  to the shaft  16 . 
         [0053]    The shaft  16  is partially disposed in an aperture  28  formed as part of the housing  12 . Also located in the aperture  28  is a first bearing assembly (not shown), and a second bearing assembly  30 , which support the shaft  16 , and allow for the shaft  16  to rotate relative to the housing  12 . The first bearing assembly is sealed in the aperture  28  by a plug, and the second bearing assembly  30  is also sealed in the aperture  28  by a C-washer  34 , located in a groove  50  formed as part of the shaft  16 . The second bearing assembly  30  is located between the C-washer  34  and the end of the shaft  16 , and is located inside and supported by a boss  52  formed as part of the housing  12 . 
         [0054]    The housing  12  also includes a cavity, and disposed in the cavity is an actuator, which in this embodiment is an electric motor  38 , held in place by two motor screws  40 . Attached to the shaft of the motor  38  is a first gear, or pinion gear  42 . The pinion gear  42  is in mesh with a second gear, or intermediate gear  44 . The intermediate gear  44  is mounted on an intermediate shaft  46 , and the intermediate shaft  46  partially extends into an aperture  48  formed as part of the housing  12 . Also formed as part of the intermediate gear  44  is a middle gear (not shown), which is smaller in diameter compared to the intermediate gear  44 . The middle gear is in mesh with a sector gear  58 , and the sector gear  58  is mounted on the shaft  16 , either through a press fit connection, or some other type of connection. 
         [0055]    The assembly  10  also includes an opening spring  62  and a closing spring  64 . The opening spring  62  has a first end  62   a  and a second end  62   b , and the first end  62   a  is in contact with a first pin, shown generally at  66 . When assembled, the opening spring  62  circumscribes part of the closing spring  64 , and the closing spring  64  also includes a first end  64   a  and a second end  64   b . The first end  64   a  of the closing spring  64  is adjacent the first end  62  of the opening spring  62 , as shown in  FIGS. 2, 4, and 7A-7D , and therefore both the opening spring  62  and closing spring  64  may be adjusted by the first pin  66 . 
         [0056]    In this embodiment, the first pin  66  is an excenter pin  66 , which is disposed in a mounting aperture  68  formed as part of the housing  12 . The excenter pin  66  includes a main body  66   a , which is cylindrically shaped, and integrally formed with the main body  66   a  is a drive portion  66   b , a cam  66   c , a knurled portion  66   d , a press-zone portion  66   e , and a reduced diameter portion  66   f . The cam  66   c  is centrally located on the main body  66   a , the drive portion  66   b  is located on one side of the cam  66   c , and the knurled portion  66   d  is located on the other side of the cam  66   c . The press-zone portion  66   e  is adjacent the knurled portion  66   d . The aperture  68  is shaped such that the pin  66  is able to be pressed into the aperture  68 , and have a press-fit connection. During assembly, the pin  66  is inserted into the aperture  68 , and the reduced diameter portion  66   e  facilitates the insertion of the pin  66  into the aperture  68 . The pin  66  is inserted into the aperture  68 , but only such that the press-zone portion  66   e  is located in the aperture  68 , and the rest of the pin  66 , including the knurled portion  66   d  is not located in the aperture  68 . The pin  66  is positioned such that the cam  66   c  is in contact with the first end  62   a  of the opening spring  62 , as shown in  FIGS. 7A-7B . The drive portion  66   b  is then used to rotate the pin  66  such that position of the cam  66   c  is changed relative to the first end  62   a  of the opening spring  62 . The cam  66   c  is shaped to change the position of the first end  62   a  of the opening spring  62  and the first end  64   a  of the closing spring  64  as the pin  66  is rotated, which therefore changes the position of the sector gear  58 , the shaft  16 , and therefore the valve plate  20 , as shown in  FIGS. 7C-7D . This adjustment of the valve plate  20  changes the “default flow position” of the valve plate  20 . The valve plate  20  is placed in the default flow position as a result of the biasing force applied from the springs  62 , 64  when the motor  38  is deactivated, and not being used to control the movement of the valve plate  20 . This adjustment of the valve plate  20  allows for adjustment of the default flow of air through the central port  14  when the motor  38  is deactivated. 
         [0057]    The shape of the cam  66   c  allows for the default flow position of the valve plate  20  to be adjusted in very small increments, such as, but not limited to, increments of ±0.10 degrees, which essentially reduces the tolerance during assembly by a factor of 3.5 due to the ability to adjust the position of the excentric pin  66 . Once the pin  66  is rotated to the desired position, the pin  66  is then further pressed into the aperture  68  such that the knurled portion  66   d  is pressed into the aperture  68 . As the knurled portion  66   d  is pressed into the aperture  68 , the aperture  68  partially deforms around the knurled portion  66   d . The deformation of the area of the aperture  68  around the knurled portion  66   d  locks the pin  66  in the desired portion, and prevents the pin  66  from rotating to an undesired position. 
         [0058]    The cam  66   c  is shaped to change the position of the ends  62   a , 64   a  of each spring  62 , 64  as the pin  66  is rotated. The shape of the cam  66   c  may be varied to alter how the rotation of the pin  66  changes the position of the ends  62   a , 64   a  of each spring  62 , 64 . Referring to  FIGS. 6A-6F , the pin  66  has a first axis  70 , which extends through the center of the pin  66 . The cam  66   c  in this embodiment has a shape that corresponds to a section of a cylinder having a larger diameter than the diameter of the main body  66   a . The pin  66  also has a second axis  72 , which represents the axis  72  of the cam  66   c , and the second axis  72  is offset from the first axis  70 . In this embodiment, the second axis  72  is offset from the first axis  70  by a distance  74  of 0.65 millimeters; however, it is within the scope of the invention that other distances may be used. The cam  66   c  also has an arcuate portion  76 , which begins at a first tangential point  78 , and the arcuate portion  76  extends at an angle  86  of 180° as shown in  FIG. 6F . The arcuate portion  76  ends at an end surface  80 . The end surface  80  is substantially flat, and is tangential to the main body  66   a , and the end surface  80  ends at a second tangential point  82 . The radius  84  of the cam  66   c  in this embodiment is 2.48 millimeters, but it is within the scope of the invention that the radius  84  may vary, and may be changed to suit a particular application. 
         [0059]    As mentioned above, the cam  66   c  has a shape that corresponds to a section of a cylinder. The cam  66   c  extends around the main body  66   a  at the angle  86  of 180 degrees. The radius  84  of the cam  66   c , and the angle  86  about which the cam  66   c  extends may also be varied to suit a particular application. The width  76   a  of the cam  66   c  may also be varied to suit different applications, where the springs  62 , 64  are different sizes, or the size of the other components is varied as well. 
         [0060]    In this embodiment, the main body  66   a  has a radius  88  of 1.83 millimeters. The end  90  of the cam  66   c  is adjacent the end surface  80 . The difference between the radius  88  of the main body  66   a  and the radius  84  of the cam  66   c , combined with the second axis  72  being offset from the first axis  70  by the distance  74  of 0.65 millimeters, produces a max distance  92  between the outer surface  66   g  of the main body  66   a  and the end  90  of the cam  66   c . The max distance  92  is the furthest the outer surface of the cam  66   c  is from the outer surface  66   g  of the main body  66   a . The max distance  92  in this embodiment is 1.3 millimeters, but it is with the scope of the invention that the cam  66   c  and main body  66   a  may be of different sizes and oriented differently relative to one another, such that the max distance  92  may be varied. 
         [0061]    The second end  62   b  of the opening spring  62  is engaged with a tab portion  94  formed as part of the sector gear  58 . The second end  64   b  of the closing spring  64  is positioned adjacent a spring stop  96  formed as part of the housing  12 . In addition to the pin  66 , the first end  62   a  of the opening spring  62  is also positioned against a spring stop  98  formed as part of the sector gear  58 . 
         [0062]    Connected to the housing  12  is a cover  100 , and disposed between the cover  100  and the housing  12  is a seal (not shown) which surrounds an outer lip  104  formed as part of the housing  12 . The cover  100  is connected to the housing  12  using a plurality of clips  106 . The cover  100  also includes a connector  108  which is in electrical communication with the motor  38 , such that the connector  108  is able to be connected to a source of power to provide power to the motor  38 . Integrally formed with the cover  100  is a lead frame, which places the connector  108  in electrical communication with a position sensor, used to detect the angle of rotation of the sector gear  58 . 
         [0063]    In operation, the closing spring  64  biases the sector gear  58 , and therefore the shaft  16  and throttle plate  20  such that the throttle plate  20  is in a closed position, such that the central bore  14  is substantially closed, or blocked completely, depending upon how the assembly  10  is configured. When current is applied to the motor  38 , the pinion gear  42  is rotated, which causes the rotation of the intermediate gear  44 , the second or middle gear of the intermediate gear  44 , and the sector gear  58 . To rotate the sector gear  58 , the bias applied to the sector gear  58  by the closing spring  64  is overcome. The amount of rotation of the sector gear  58  is in proportion to the amount of current applied to the motor  38  combined with the force applied to the sector gear  58  from the opening spring  62 , which must overcome the force applied to the sector gear  58  by the closing spring  64 . Since the sector gear  58  is coupled to the shaft  16 , rotation of the sector gear  58  rotates the shaft  16  to rotate the valve plate  20 . As noted above, the position sensor detects the position of the sector gear  58  and thus the plate  20  during the operation of the throttle body assembly  10 . 
         [0064]    As the sector gear  58  is rotated, the shaft  16  is rotated as well, rotating the plate  20 , and allowing increased levels of air flow through the central bore  14 . The amount of rotation of the sector gear  58  is detected by the sensor, such that the valve plate  20  may be placed in a desired position. 
         [0065]    Due to variations in tolerances in the assembly  10 , and differences in flow requirements for different applications, the default position of the valve plate  20  may need to be adjusted during assembly. The pin  66  may be rotated during assembly as described above to adjust the position of the springs  62 , 64 , to therefore change the default flow position of the valve plate  20 . The pin  66  may be rotated such that the cam  66   c  is not in contact with the first end  62   a  of the opening spring  62 , but rather the first end  62   a  of the opening spring  62  is in contact with the main body  66   a . The pin  66  may also be rotated such that the first end  62   a  is in contact anywhere along the arcuate portion  76  of the cam  66   c  in between the first tangential point  78  and the end  90  of the cam  66   c  to properly configure the springs  62 , 64 , placing the valve plate  20  in the desired position. 
         [0066]    As mentioned above, the adjustment of the pin  66  is accomplished by rotating the drive portion  66   b . In the embodiment shown in  FIGS. 2 and 5-7D , the drive portion  66   b  is an external drive portion  66   b , with several splines  66   h . In this embodiment, there are six splines  66   h , but it is within the scope of the invention that different amounts of splines  66   h  may be used. 
         [0067]    Another embodiment of the assembly  10  is shown in  FIGS. 8A-8B , with like numbers referring to like elements. In this embodiment, there is an additional aperture  114  formed as part of the housing  12  shown in  FIG. 3 , and another pin  66  may be inserted, such that the pin  66  is in contact with a gear stop  116  formed as part of the sector gear  58 . The pin  66  located in the aperture  114  may be rotated to adjust the default position of the sector gear  58 . Having a pin  66  in the aperture  68  to adjust the position of the springs  62 , 64  and a pin  66  in the aperture  114  to adjust the position of the sector gear  58  increases the precision of how the valve plate  20  may be adjusted. 
         [0068]    There are several possible alternate embodiments of the pin  66 . One of these embodiments of the pin  66  is shown in  FIGS. 9A-9B , with like numbers referring to like elements. The embodiment shown in  FIGS. 9A-9B  has an external drive portion  66   b , with an increased number of splines  66   h . There are twelve splines  66   h  in the embodiment of the pin  66  shown in  FIG. 9A-9B , and the embodiment with twelve splines  66   h  may or may not have the knurled portion  66   d.    
         [0069]    Another alternate embodiment of the pin  66  is shown in  FIG. 10A-10B , with like numbers referring to like elements. In this embodiment, the drive portion  66   b  is an internal drive portion  66   b , with six internal splines  66   h . More or less internal splines  66   h  may be used in other embodiments as desired. 
         [0070]    The pin  66  in  FIGS. 2 and 5-7D  is shown with the knurled portion  66   d . However, it is also possible to manufacture the pin  66  without the knurled portion  66   d , shown in  FIGS. 11A-11C , if the press-fit into the aperture  68  is sufficient. 
         [0071]    In all of the embodiments of the pin  66  described above, the knurled portion  66   d  may be replaced with a ribbed portion  66   i , shown in  FIGS. 12A-12C . The ribbed portion  66   i  may extend along a portion or all of the press-zone portion  66   e . The ribbed portion  66   i  is used to provide a more robust press-fit connection as the pin  66  is inserted into the corresponding apertures  68 , 114 . 
         [0072]    Yet another embodiment of the pin  66  is shown in  FIGS. 13A-13B . In this embodiment, the cam  66   c  offset from the main body  66   a , in a similar manner to the cam  66   c  described in the previous embodiments. However, the cam  66   c  in this embodiment is a full cylindrical portion, as opposed to having the shape the corresponds to a section of a cylinder. The arcuate portion  76  of the cam  66   c  extends a full 360° about the axis  72 . In this embodiment, the drive portion  66   b  is a hexagonal drive portion  66   b . The embodiment shown in  FIGS. 13A-13B  is shown without a knurled portion  66   d  or a ribbed portion  66   i , but it is within the scope of the invention that these features may be incorporated into the embodiment shown in  FIGS. 13A-13B . 
         [0073]    In other embodiments, the cover  80  may include apertures (not shown) which deform around the drive portion  66   b  of the pin  66  as the cover  80  is connected to the housing  12 . 
         [0074]    Another embodiment of the invention is shown in  FIG. 14 , with like numbers referring to like elements. In this embodiment, the pin  66  does not have a cam  66   c , but rather there is a bushing  118  which is mounted to the main body  66   a . The bushing  118  may be one of several bushings having different diameters, and the bishing having the desired diameter is chosen to configure each of the springs  62 , 64  as desired. 
         [0075]    All of the embodiments described above use both the opening spring  62  and the closing spring  64 , with the excentric pin  66  used to adjust the ends  62   a , 64   a  of the opening spring  62  and closing spring  64 . However, it is within the scope of the invention the the excentric pin  66  may be used with a single spring design, where two pins  66  are used to correctly position each end of the single spring. 
         [0076]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.