Abstract:
A disjoinable hinge mechanism having a locking cam is provided. The hinge mechanism includes a hinge assembly having a hinge pin which pivotably couples a first hinge structure to a second hinge structure. The hinge mechanism also includes a cam pivotably coupled to the hinge pin and a third hinge structure which includes a cam follower. The cam is positionable between a released position and an engaged position. The cam does not engage the cam follower when positioned in the released position. The cam engages the cam follower when positioned in the engaged position. The cam is adapted to be moved into the engaged position when an associated closure member is moved into a closed position. Thereafter, the cam remains in the engaged position during normal operation of the closure member. The second hinge structure may also include a set of locator pins which engage mounting apertures in the third hinge structure. The locator pins permit the hinge member to be rejoined so that the hinge assembly aligns correctly to the third hinge member after the hinge mechanism has been disjoined.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates generally to closure member hinge mechanisms and more particularly to a hinge mechanism for a closure member which permits the closure member to be easily removed and reinstalled in an accurate manner. 
     2. Discussion 
     It has long been recognized that three-piece disconnectable hinges may be advantageous over conventional two-piece hinges in certain applications where a closure member is installed to a device and subsequently removed and reinstalled during the course of the assembly of the device. U.S. Pat. No. 4,720,895 entitled Quick-Disconnect Door Hinge, U.S. Pat. No. 4,766,643 entitled Vehicle Door Hinge Having Vertically Separable Pivotal Connections, and U.S. Pat. No. 5,297,314 entitled Three-Piece Lateral Take-Apart Door Hinge Assembly, all of which are hereby incorporated by reference as if fully set forth herein, each disclose a multi-piece door hinge assembly having first and second portions which are disjoined by removing one or more fasteners which secure the portions together. At least one of these hinge mechanisms requires the use of specially designed fasteners which aid in the realignment of the hinge portions. 
     While such hinge mechanisms have received general acceptance, several drawbacks have been noted. One primary drawback has been the need for threaded fasteners to join and disjoin the portions of the hinge mechanism. Problems typically associated with the routine installation and removal of fasteners include loss of the fasteners, damage to the threads of the fastener or to an associated portion of the hinge mechanism, significant expenses associated with the tooling and labor for the removal and subsequent re-installation of the fasteners, and alignment problems associated with the level of clamping forces produced and the fastening sequence with which the fasteners are tightened. 
     Another primary drawback relates to the manner in which the portions of the hinge assembly are realigned. The above-referenced hinge mechanisms typically require the use of assembly tooling such as fixtures or guides that align the vehicle door to the vehicle body in a predetermined orientation and relationship until the fasteners for securing the portions of the hinge mechanism together are threadably engaged. Such tooling is typically expensive and does not add value to the vehicle. 
     SUMMARY OF THE INVENTION 
     It is one object of the present invention to provide a hinge mechanism with a locking cam which permits the hinge mechanism to be readily disjoined and rejoined. 
     It is another object of the present invention to provide a hinge mechanism with an integral alignment mechanism which permits the hinge mechanism to be easily and accurately rejoined. 
     A disjoinable hinge mechanism having a locking cam is provided. The hinge mechanism includes a hinge assembly having a hinge pin which pivotably couples a first hinge structure to a second hinge structure. The hinge mechanism also includes a cain pivotably coupled to the hinge pin and a third hinge structure which includes a cam follower. The cam is positionable between a released position and an engaged position. The cam does not engage the cam follower when positioned in the released position. The cam engages the cam follower when positioned in the engaged position. The cam is adapted to be moved into the engaged position when an associated closure member is moved into a closed position. Thereafter, the cam remains in the engaged position during normal operation of the closure member. The second hinge structure may also include a set of locator pins which engage mounting apertures in the third hinge structure. The locator pins permit the hinge member to be rejoined so that the hinge assembly aligns correctly to the third hinge member after the hinge mechanism has been disjoined. 
     Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partial sectional view of a vehicle illustrating a hinge mechanism constructed in accordance with the teachings of a preferred embodiment of the present invention, with the hinge mechanism in an orientation such that the vehicle door is in a closed position; 
     FIG. 1A is a partial sectional view similar to that of FIG. 1 but illustrating the hinge mechanism in an orientation such that the vehicle door is in an open position; 
     FIG. 2 is a front view of a portion of the hinge mechanism of FIG. 1; 
     FIG. 3 is a view taken along the line  3 — 3  of FIG. 2; 
     FIG. 4 is a front view of a portion of the hinge mechanism of FIG. 1; 
     FIG. 5 is a view taken along the line  5 — 5  of FIG. 4; 
     FIG. 6 is a top view of a portion of the hinge mechanism of FIG. 1; 
     FIG. 7 is a rear view of a portion of the hinge mechanism of FIG. 1; 
     FIG. 8 is a top view of a portion of the hinge mechanism shown in FIG. 1; 
     FIG. 9 is an end view of a portion of the hinge mechanisim shown in FIG. 8; 
     FIG. 10 is a view of a portion of the hinge mechanism taken in direction arrow  10  of FIG. 8; 
     FIG. 11A through 11C are views of a portion of the hinge mechanism of FIG. 1 as the cam is being moved to the engaged position; 
     FIG. 1 2  is a perspective view of a tool for disengaging the cam; 
     FIG. 13 is a cross-sectional view taken along the line  13 — 13  of FIG. 12; 
     FIG. 14 is a cross-sectional view of a portion of a hinge mechanism constructed according to another preferred embodiment of the present invention; 
     FIG. 15 is a partial sectional view illustrating a portion of a hinge mechanism constructed according to yet another preferred embodiment of the present invention; and 
     FIG. 16 is an enlarged view of a portion of the hinge mechanism of FIG.  15 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIGS. 1 and 1A of the drawings, a hinge mechanism constructed in accordance with the teachings of the present invention is generally indicated by reference numeral  10 . Hinge mechanism  10  is shown in operative association with an apparatus  12  having a closure member  14  and a frame structure  16  which defines a closure member aperture  18 . Although the particular apparatus  12  illustrated is an automotive vehicle, it will be understood that the teachings of the present invention have applicability to other types of devices and as such, will not be limited in application to automotive vehicles. 
     A first hinge portion  20  of hinge mechanism  10  is coupled to closure member  14  and a second hinge portion  22  of hinge mechanism  10  is coupled to frame structure  16 . First hinge portion  20  includes a hinge assembly  30 , a cam member  32  and a cam positioning member  34 . Hinge assembly  30  includes a first hinge structure  40 , a second hinge structure  42 , a hinge pin  44 , a pair of pin bushings  46  and a pair of locators  48 . Second hinge portion  22  includes a third hinge structure  50  and a cam follower  52 . 
     In FIGS. 2 and 3, first hinge structure  40  is illustrated as being a stamped metal fabrication having a U-shaped yoke  60  and a pair of mounting flanges  62 . Yoke  60  includes a central member  64  and a pair of fork members  66   a ,  66   b  which are coupled to opposite ends of central member  64 . A first pin aperture  68  and a first release aperture  70  are formed into each of the fork members  66 . First pin apertures  68  are spaced apart from central member  64  and a hinge pin axis  72  is formed therethrough. 
     Each of the mounting flanges  62  is coupled to a fork member  66  and extends outwardly therefrom. Each mounting flange  62  also includes a first securing aperture  74  which permits first hinge portion  20  to be fixedly but removably secured to closure member  14  through a pair of conventional fasteners (not shown). 
     In FIGS. 4 and 5, second hinge structure  42  is illustrated as including a base member  80 , a pair of trunnions  82  and a tongue  84 . Base member  80  includes a pair of locator apertures  86  which are spaced apart along a generally vertical axis. Base member  80  also includes a cam recess  88  which is centered between the pair of locator apertures  86 . Each of the trunnions  82  is coupled to base member  80  and extend outwardly therefrom in a generally perpendicular direction. Each trunnion  82  includes a second pin aperture  90 . Tongue  84  is coupled to base member  80  and extends outwardly therefrom in a generally perpendicular direction. 
     Hinge pin  44  is conventional in construction and need not be described in significant detail. Briefly, hinge pin  44  includes a first headed portion  100 , a knurled portion (not shown), a body portion  104  and a second headed portion  106 . The knurled portion is typically larger in diameter than body portion  104  and first pin apertures  68 . As such, insertion of the knurled portion into either of the first pin apertures  68  causes the associated fork member  66  to fixedly engage the knurled portion, thereby inhibiting withdrawal of hinge pin  44  from first hinge structure  40 . Second headed portion  106  is formed after first hinge portion  20  has been assembled and inhibits hinge pin  44  from being removed therefrom. Second headed portion  106  is preferably conventionally formed in a staking or spinning operation. Pin bushings  46  are also conventional in construction and need not be described in significant detail. Briefly, pin bushings  46  include a thrust flange  110  and a body portion  112 . Thrust flange  110  is washer-shaped and includes a low-friction coating, such as Teflon, on its thrust surface  114 . Body portion  112  is a hollow cylinder and includes a low-friction coating, such as Teflon, on its interior surface. 
     In FIG. 6, cam member  32  is illustrated as being a generally C-shaped member having a third pin aperture  120 , a second release aperture  122  and an arcuate cam surface  124 . Arcade cam surface  124  is shown to include a first portion  126 , a second portion  128  and a third portion  130 . Third pin aperture  1   20  is adapted to receive cam positioning member  34 . 
     In FIG. 7, cam positioning member  34  is illustrated as being a generally cylindrical bushing  140  which is fixedly coupled to hinge pin  44  through a conventional securing means such as press-fitting or adhesives. Bushing  140  includes a body portion  142  and a pair of flanges  144 . Body portion  142  is sized to fit within third pin aperture  120  to permit cam member  32  to rotate about body portion  142 . Each of the flanges  144  is fixedly coupled to an opposite end of body portion  142 . Each of the flanges  144  is sized larger than third pin aperture  120  to inhibit axial movement of cam member  32  along hinge pin  44 . 
     In the particular embodiment illustrated, each of the locators  48  are a rivet  150  having a head portion  152 , a body portion  154  and an insertion portion  156 . The body portions  154  of rivets  150  are sized to fit within the locator apertures  86  in the second hinge structure  42 . Body portions  154  are shown to be generally cylindrical and positioned perpendicular to base member  80 . Each of the insertion portions  156  is coupled to the body portion  154  and is conical in shape. Head portions  152  are each coupled to a distal end of their respective body portions  154  and are operable for fixedly securing body portion  154  to base member  80 . 
     Locators  48  are fixedly secured to base member  80 . One of the pair of pin bushings  46  is inserted into each of the second pin apertures  90  in the trunnions  82  of the second hinge structure  42 . Second hinge structure  42  is positioned proximate to first hinge structure  40 . Cylindrical bushing  140  is coupled to the third pin aperture  120  of cam member  32  and the resulting assembly is positioned proximate to first and second hinge structures  40  and  42 . Hinge pin  44  is inserted through the first pin aperture  68  in fork member  66   a  and pin bushing  46   a . Hinge pin  44  is next pressed through cylindrical bushing  140 . Hinge pin  44  is then pressed through pin bushing  46   b  and the first pin aperture  68  in fork member  66   b.    
     Pin bushings  46  permit second hinge structure  42  to rotate about hinge pin axis  72 . The thrust surfaces  114  of the thrust flanges  110  contact the fork members  66  so as to minimize clearance between the first and second hinge structures  40  and  44  while providing a low-friction bearing surface. Cam member  32  may freely rotate about hinge pin axis  72  due to the slip-fit condition between it and bushing  140 . 
     In FIGS. 8 through 10, third hinge structure  50  is illustrated as a five-sided stamped sheet metal fabrication having a first mounting member  160 , a second mounting member  162 , a lateral member  164  and upper and lower members  166  and  168 , respectively. First mounting member  160  includes a pair of second securing apertures  170  which permit third hinge structure  50  to be fixedly but removably coupled to frame structure  16  through a pair of conventional threaded fasteners (not shown). 
     Second mounting member  162  includes first and second mounting apertures  172  and  174 , respectively. First mounting aperture  172  extends through second mounting member  162  and is generally cylindrical in shape. Second mounting aperture  174  also extends through second mounting member  162 . Second mountinig aperture  174  is slotted, having a minor diameter which is approximately equal to the diameter of first mounting aperture  172 . The major axis  178  of second mounting aperture  174  is parallel to the centerline  180  of the first mounting aperture  172 . Preferably, major axis  178  and centerline  180  coincide. 
     Lateral member  164  is shown to include a cam aperture  184  sized to receive cam member  32 . Lateral member  164  is fixedly coupled to first mounting member  160  at a first end and to second mounting member  162  at a distal end. A first recessed cavity  186  is formed into the first mounting member  160  and lateral member  164  proximate the cam aperture  184 . A second recessed cavity  188  is formed into the second mounting member  162  and lateral member  164  proximate the intersection of these two surfaces. 
     Upper member  166  is coupled to the top portion of lateral member  164  and to the top portion of first mounting member  160 . Lower member  168  is similar in construction to upper member  166  and is coupled to the bottom portion of lateral member  164  and to the bottom portion of first mounting member  160 . Upper and lower members  166  and  168  function as gussets, strengthening third hinge structure  50  and preventing relative movement between first mounting member  160  and lateral member  164 . Each of the upper and lower members  166  and  168  includes a fourth pin aperture  190 . 
     Referring back to FIGS. 1 and 1A cam follower  52  is illustrated as being a cylindrical pin  200  which is similar in construction to hinge pin  44 . Pin  200  is conventional in construction and need not be described in significant detail. Briefly, pin  200  includes a first headed portion  202  a knurled portion (not shown), a body portion  206  and a second headed portion (not shown). The knurled portion is typically larger in diameter than body portion  206  and fourth pin apertures  190 . As such, insertion of the knurled portion into either of the fourth pin apertures  190  causes the associated upper or lower member  166  or  168  to fixedly engage the knurled portion, thereby inhibiting withdrawal of pin  200  from third hinge structure  50 . The second headed portion of pin  200  is formed after pin  200  has been inserted to third hinge structure  50  and inhibits pin  200  from being removed therefrom. The second headed portion of pin  200  is preferably conventionally formed in a staking or spinning operation. 
     With continued reference to FIG. 1 and 1A and additional reference to FIGS. 11A and 11B, the assembly of hinge mechanism  10  will now be discussed in detail. In assembling hinge mechanism  10 , the body portions  154  of the rivets  150  are introduced to the first and second mounting apertures  172  and  174 , and the first and second hinge portions  20  and  22  are pushed together such that base member  80  abuts second mounting member  162 . As the insertion portions  156  of the rivets  150  are tapered, the rivets  150  act as guide pins and accurately guide the first and second hinge portions  20  and  22  together. 
     As those skilled in the art should appreciate, the configuration of the body portion  154  of rivets  150  and the first and second mounting apertures  172  and  174  permits the second hinge portion  22  to be installed to the first hinge portion  20  in a highly accurate manner. Essentially, rivet  150   a  acts as a primary datum locator to establish the position of first hinge portion  20  relative to second hinge portion  22  along two datum lines. Rivet  150   b  acts as a secondary datum locator to establish the rotational position of first hinge portion  20  about the two datum lines. 
     Once the locators  48  have engaged their respective first or second mounting aperture  172  or  174 , cam member  32  is then pivoted about hinge pin  44  from a release position, wherein cam member  32  is not engaged to cam follower  52 , to an engaged position, wherein cam member  32  engages cam follower  52 . In the particular embodiment illustrated, cam member  32  is rotated about hinge pin  44  toward third hinge structure  50  and through cam aperture  184 . 
     Continued rotation of cam member  32  in this direction causes the first portion  126  of the arcuate cam surface  124  to engage pin  200 . Contact between first portion  126  and pin  200  creates a clamping force which tends to draw the first and second hinge portions  20  and  22  together such that base member  80  abuts second mounting member  162 . Further rotation of cam member  32  in this direction increases the clamping force until pin  200  contacts the second portion  128  of arcuate cam surface  124 . The second portion  128  of arcuate cam surface  124  is operable for inhibiting cam member  32  from returning to the release position. 
     When the second portion  128  of arcuate cam surface  124  engages pin  200 , cam member  32  is operable for maintaining a predetermined minimum clampload on the first and second hinge portions  20  and  22  which is transmitted through base member  80  and second mounting member  162 . The first and second recessed cavities  186  and  188  increase the strength of third hinge structure  50  as well as prevent contact between the third portion  130  of the arcuate cam surface  124  and the third hinge structure  50 . 
     Typically, hinge mechanism  10  is provided to an assembly area in a fully assembled condition. Thereafter, a pair of hinge mechanisms  10  are installed to a closure member  14 . The sub-assembled closure member  14  is then aligned and secured to a frame structure  16 . Removal of the closure member  14  from the frame structure  16  may be easily accomplished through a removal tool, such as the tool shown in FIGS. 12 and 13. Tool  220  is shown to include a plate member  222 , a stationary pin  224 , a spring-loaded pin assembly  226 , a stationary handle  228  and a movable handle  230 . Stationary pin  224  is fixedly coupled to plate member  222  and extends therefrom in a first direction along a first axis  260 . Spring-loaded pin assembly  226  is coupled to plate member  222  and extends therefrom in a direction opposite the first direction and along a second axis  262  parallel to and spaced apart from the first axis  260 . Spring-loaded pin assembly  226  is also permitted to slide along second axis  262 . Stationary handle  228  is coupled to plate member  222 . Movable handle  230  is coupled to spring-loaded pin assembly  226  such that when movable handle  230  is moved toward stationary handle  228 , spring-loaded pin assembly  226  retracts along second axis  262  toward plate member  222 . 
     Preferably, closure member  14  is positioned in a partially open position and tool  220  is engaged to hinge mechanism  10 . Specifically, movable handle  230  is moved toward stationary handle  228  to draw spring-loaded pin assembly  226  toward plate member  222 . Stationary pin  224  is next positioned into one of the first and second release apertures  70  and  122 . In the particular embodiment illustrated, stationary pin  224  is positioned into second release aperture  122 . Tool  220  is then rotated about stationary pin  224  so as to align spring-loaded pin assembly  226  to one of the first release apertures  70 . When spring-loaded pin assembly  226  is aligned to one of the first release apertures  70 , the movable handle  230  is released to permit the spring-loaded pin assembly  226  to enter into the first release aperture  70 . 
     Tool  220  is operable for inhibiting relative motion between cam member  32  and first hinge structure  40 . Consequently, moving closure member  14  toward the fully open position causes cam member  32  to move from the engaged position to the release position. Depending upon the length of the closure member  14 , the closure member  14  may produce a tremendous mechanical leveraging effect which eliminates the need for other tooling to remove cam member  32  from cam follower  52 . 
     Following the removal of cam member  32  from cam follower  52 , the first and second portions of hinge mechanism  10  may be separated to permit closure member  14  to be removed from frame structure  16 . Re-installation of closure member  14  to frame structure  16  is greatly simplified as a result of the cam member  32  and locators  48 . As discussed above, locators  48  are operable for efficiently and accurately aligning the closure member  14  to the frame structure. 
     Closure member  14  may also be advantageously employed during the reinstallation process to engage cam member  32  to cam follower  52 . Referring back to FIGS. 11A and 11B, contact between cam member  32  and closure member  14  when the closure member  14  is moved from the fully open position to the fully closed position drives cam member  32  from the release position to the engaged position. As specifically shown in FIG. 11C, an installation tool  270  may be employed to ensure that cam member  32  has been placed in the engaged position. 
     Installation tool  270  is essentially a wedge that is placed between cam member  32  and closure member  14  which takes up any space which is intended to serve as clearance between these two components. Use of such clearance space is conventional and eliminates noise generated by contact between the cam member  32  and closure member  14  when the closure member  14  is placed in the closed position. Installation tool  270  is removed once cam member  32  has been returned to the engaged position. 
     In FIG. 14 a secondary securing device  280  is shown to include a threaded fastener  282  and a threaded hole  284  formed into the third hinge structure  50 ′ proximate the first recessed cavity  186 ′. Threaded fastener  282  threadably engages threaded hole  284  and protrudes toward the interior of third hinge structure  50 ′. The end  286  of threaded fastener  282  is proximate cam member  32  and inhibits its movement toward the release position. 
     Another secondary securing device  300  is illustrated in FIGS. 15 and 16. Secondary securing device  300  includes a retaining bracket  302  and a threaded fastener  304 . Retaining bracket  302  is generally L-shaped and includes a base portion  310  and a leg portion  312 . Base portion  310  is fixedly coupled to cam member  32  by a suitable fastening means, such as spot welding. Leg portion  312  includes a fastener aperture  314  which will be discussed in greater detail below. 
     Fastener  304  includes a head structure  320  and a threaded body portion  322 . Head structure  320  includes a conventional drive portion  324  and a flange portion  326 . Drive portion  324  is illustrated as being hexagonal in shape to permit fastener  304  to be installed with a standard socket wrench (not shown). Flange portion  326  is adapted to transmit clamping forces to leg portion  312  and includes an annular ring  328  formed into the underside  330  of flange portion  326 . Annular ring  328  is illustrated as having tooth  332  with a triangular cross-section. The included angle of the tip  334  of tooth  332  is from about 30 to about 120 degrees and preferably from about 60 to about 90 degrees. 
     Fastener  304  is installed to hinge mechanism  10 ″ after cam member  32  has engaged cam follower  52 . Body portion  322  is introduced through fastener aperture  314  and threadably engaged to a threaded securing aperture  340  in third hinge structure  50 ″. Due to variation in the fabrication of the components and assembly of hinge mechanism  10 ″, fastener aperture  314  is sized well larger in diameter than body portion  322  to permit body portion  322  to threadably engage securing aperture  340 . Fastener  304  is rotated sufficiently to permit head structure  320  to transmit a clamping force which tends to draw third hinge structure  50  and leg portion  312  together. The clamping force is initially transmitted through annular ring  328  which causes tooth  332  to machine or deform a corresponding groove  344  into leg portion  312 . 
     In addition to inhibiting cam member  32  from becoming disengaged from cam follower  52 , the configuration of secondary securing device  300  in this manner advantageously improves the shear strength of hinge mechanism  10 ″. Engagement of the teeth  332  of annular ring  328  into groove  344  improves the resistance of hinge mechanism  10 ″ to shear forces created by the weight of the closure member  14  and any downward forces that are applied to the closure member  14 . 
     While the invention has been described in the specification and illustrated in the drawings with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention as defined in the claims. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out this invention, but that the invention will include any embodiments falling within the description of the appended claims.