Park brake cable system including connector clip
A park brake cable system including a brake actuation lever, a connector clip having a first end and a second end, and including a shear member, having a shear failure force, positioned between the first and second ends. A brake assembly, a front cable strand having a first end and a second end, the first end attached to the brake actuation lever, and the second end engaging the shear member on the connector clip are also included. Further included are a rear cable strand having a first end and a second end, the first end attached to the second end of the connector clip and the second end attached to the rear brake assembly, and a tensioner is attached in a tension force transmitting relationship with the front cable strand and the rear cable strand. Applying tension to the front and rear cable strands by the tensioner creates at least the sufficient shear failure force to cause the second end of the front cable strand to break the shear member and move to the first end of the connector clip. The cable system also includes a connector clip including a main body having an interior cavity, and open first and second ends, and a shear member extending across a portion of the interior cavity.
This is a division of application Ser. No. 09/064,402, filed on Apr. 22, 1998 now U.S. Pat. No. 5,983,745, which is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTIONThis invention relates to cable connector clips and particularly to connector clips of the type used to adjust the tension of park brake cable systems used in motor vehicles.
BACKGROUND OF THE INVENTIONMost motor vehicles utilize some type of cable system to engage and release the rear brakes to act as a parking brake. The parking brake system basically includes a pedal or lever actuator, a front cable strand, a left rear cable strand, a right rear cable strand, a front cable conduit, a left rear cable conduit, and a right rear cable conduit through which the front and rear cable strands extend, respectively, an equalizer assembly positioned between the front and rear cable strands, tensioning rod and nut, cable connector and left and right rear brake assemblies. The left and right rear cable strands are attached to the left and right rear brake assemblies, respectively.
The following, is a description of the general operation of a park brake system to assist in understanding the invention. A brake pedal or lever is actuated to apply tension to the front cable strand. The front cable strand is connected to the left and right rear cable strands through an equalizer. The function of the equalizer is to equally distribute tension in the front cable to the right and left rear cables so that the tension is balanced between the cables extending to the left and right rear brake assemblies when the lever is actuated. The added tension applied to the rear cable strands overcome the spring in each rear brake assembly to cause the brakes to engage and act as a parking brake. The spring normally holds the rear brake shoes or calipers open and thus disengaged.
In operation, it is desirable that high tension exists in the cables even when the pedal or lever is in the non-actuated position (residual tension). Adequate residual tension in the cable system means that the pedal or lever does not have to be extended a great distance to achieve a strong force at the brake assemblies to provide for secure engagement. Furthermore, the high tension helps eliminate the slack and voids in the cables and conduits, which reduces creep or lengthening of the cable thus making consistent the range of motion of the lever. This same high level of consistency in actuator travel will also exist from vehicle to vehicle.
The objective at the time of installation of the park brake cable system is, therefore, to introduce enough high tension to the cables so that “voids” in the conduit system and cable stretch are effectively removed In this way the system will not continue to loosen-up over repeated actuation and there will be continued consistency in pedal or lever travel over the life of the vehicle and from vehicle to vehicle This objective is difficult to achieve in a rapid and inexpensive manner such as required in a high volume automotive assembly line environment.
Various methods of tensioning the cable system are used, all with the goal of introducing enough tension to the cable system during installation to remove voids minimize variation in actuator travel from vehicle to vehicle. One method of tensioning the cable system is to tension the cables during installation to a level where the brakes are almost starting to drag and no further. In this method a predefined level of tension is determined and the park brake cable system of all the vehicles on the assembly line are tensioned to this level. This method typically results in wide variation in lever travel from vehicle to vehicle and also results in a system that loosens-up over time since the voids in the cable and conduit are not sufficiently removed. Merely tensioning to a level just below brake drag does not introduce enough initial tension to completely remove system voids and eliminate cable stretch.
Another method is to tension the cable system during installation to a level far beyond what is required to merely engage the brakes. In doing so, many of the voids in the cable and conduit system are removed and the cable stretch accomplished. The tension in the cable system is then reduced just enough until the brake assemblies are no longer engaged. This method results in an optimally tensioned park brake cable system, however, it is time consuming because the cables must be initially tensioned to a very high level and then de-tensioned to a desired residual tension level. Expensive instruments are required to measure the tension in the cable system at both the tensioning and de-tensioning steps to insure the final or residual tension in the cable system is adequate. This method takes a relatively long time to perform during production of the vehicle.
There is a continuing need in the art for an improved park brake cable system and method for adjusting, including a cable connector clip, that provides the proper amount of tensioning and tension relief for consistent park brake performance for a vehicle, and minimal variation of park brake performance from vehicle to vehicle. It is with the shortcomings of the prior art in mind that the instant invention was developed
SUMMARY OF THE INVENTIONThe invention described herein provides a simple mechanism that simulates the second optimal method without requiring the time necessary to both tension and de-tension the cable system, and without requiring the expensive tooling and instrumentation necessary to perform this method of brake adjustment.
The benefit of the shear tab cable connector is two fold: 1) to reduce variation in cable and actuator travel from vehicle to vehicle and 2) to allow the cable system to be over-tensioned to remove voids and then to release sufficient tension to unlock the brakes and allow adequate residual tension to remain in the cable system. In this way the cable system does not loosen appreciably over time. An additional objective of the shear tab cable connector is to provide for an optimal cable system tensioning method that does not consume a great deal of time and is therefore suitable for rapid automotive assembly operations.
These objectives are accomplished with the shear tab cable connector as described herein, where during the vehicle assembly process the cable is highly tensioned to a point beyond what is required to lock-up the rear brake assemblies. The shear member is then broken to allow the cable system to slightly de-tension to a desired residual tension level. The amount of residual tension in the cable system is enough so that when the pedal or lever is released the rear brakes disengage only enough to disengage the rear brake assemblies so they are no longer dragging. The shear tab member can be broken by activation of the brake lever, or by continued adjustment of the tensioning means.
The instant invention allows a cable tension adjusting process where the cables are over-tensioned to remove system voids and then loosened only enough to just disengage the brake assemblies. Significant residual tension is therefore left in the cable system even when the brake actuator lever is in the released position, the result being a tight, responsive cable system with little variation in brake actuator lever travel from vehicle to vehicle and a cable system that will not loosen significantly over the life of the vehicle.
The present invention encompasses a park brake cable system including a brake actuation lever, a connector clip having a first end and a second end, and including a shear member, having a shear failure force, positioned between the first and second ends. A brake assembly, a front cable strand having a first and second ends, the first end attached to the brake actuation lever, and the second end engaging the shear member on the connector clip are also included. Further included are a rear cable strand having a first end and a second end, the first end attached to the second end of the connector clip and the second end attached to the rear brake assembly, and tensioner means are attached in a tension force transmitting relationship with the front cable strand and the rear cable strand. Applying tension to the front and rear cable strands by the tensioner means creates at least the sufficient shear failure force to cause the second end of the front cable strand to break the shear member and move to the first end of the connector clip.
In further detail, the instant invention also includes a rear left brake assembly, a rear right brake assembly, an equalizer structure, a rear left cable strand attached to and extending between the equalizer and the rear left brake assembly, and a rear right cable strand attached to and extending between the equalizer and the rear right brake assembly. The actuation of the tensioner means tensions the front, rear right and rear left cable strands.
The tensioner means can be positioned either on the equalizer or on the brake actuation lever.
The present invention also includes a connector clip including a main body having an interior cavity, and open first and second ends, and a shear member extending across a portion of the interior cavity.
In further detail, the present invention also includes a connector clip for park brake cable systems where the shear member has a partial cylindrical main body and defines a tab extending orthogonally inwardly, the main body defining an outer surface and an aperture formed through the main body from the outer surface to the interior cavity, the shear member mounting on the outer surface and the tab extending through the aperture to extend across at least a portion of the interior cavity.
Alternatively, the connector clip also includes the main body having a cylindrical body defining a bore therethrough having interior side walls, the shear member is a shear disk attached to the interior side walls and extends across the bore.
The present invention encompasses a method of adjusting the tension in a park cable brake system comprising the steps of providing a brake actuation lever, a connector clip having a first end and a second end, and including a shear member, having a shear failure force, positioned between the first and second ends, a brake assembly, a front cable strand having a first and second ends, the first end attached to the brake actuation lever, and the second end engaging the shear member on the connector clip, a rear cable strand having a first end and a second end, the first end attached to the second end of the connector clip and the second end attached to the rear brake assembly, and tensioner means attached in a tension force transmitting relationship with the front cable strand and the rear cable strand; tensioning the first and second cable strands with the tensioner means; and breaking the shear member.
In more detail, the present invention also encompasses a method having the additional steps of actuating the brake lever to break the shear member.
Alternatively, the present invention also encompasses a method having the additional steps of tensioning a first and second cable strands with a tensioner means; and breaking a shear member engaged by one end of the first cable strand.
Accordingly, it is the primary object of the present invention to provide a park brake cable system that is easily adjusted and set at the appropriate tension during assembly.
It is another object of the present invention to provide a connector clip for park brake cable systems that includes a shear member that allows sufficient high tension application, and once broken, establishes the proper residual stress in the cable system.
Other aspects, features and details of the present invention can be more completely understood by reference to the following detailed description of a preferred embodiment, in conjunction with the drawings, and from the appended claims.
As a general description with reference to
The cable systems described below fall into one of two categories: a side-pull park brake cable system, also referred to as a reaction-conduit system, and a center-pull park brake cable system. Each of these two types of cable systems includes a brake activation lever movably attached to the vehicle, a front cable strand, an equalizer structure, left and right rear cable strands, conduits through which the cables extend, left and right rear brake assemblies, and a connector clip having a shear member.
The park brake cable system of the present invention is described below with respect to brake assemblies having brake pads and brake drums. It is contemplated that the park brake cable system of the present invention would work equally well with disk brake systems having calipers and rotors.
The connecting clip on which the inventive park brake system is based includes a body structure having either a shear tab or a shear disk attached thereto. The shear member can be integrally formed with the connector clip, or can be a separate member attached to the connector clip. The shear tab or disk is designed to require a calculated shear force to break the tab or disk from the body member, which allows the tension in the cable system to change from a desired high tension (for removing voids and stretching the cable) to a desired residual tension.
The park brake cable system, the connector clip and shear member, and associated method, are described below in detail.
Referring to
The right rear cable strand 68 extends through a conduit 72, similar to the conduit 56 described above, and attaches to a right rear brake assembly 74. The assembly shown in
The rear right cable strand 68 at its first end includes a crimp-on-end bead 90 which is inserted into the connector clip 64 of the present invention, which is seated in the second end 92 of the connector clip 64 of the present invention. The first end 94 of the rear left cable strand 66 is attached to a threaded rod 96, such as the shank of a bolt or screw. The threaded rod 96 is received in a tension adjusting nut 98, which is in turn rotatably engaged in the second end 70 of the equalizer structure 60. The tension adjusting nut 98 is fixed in axial position with respect to the equalizer 60, but is allowed to rotate. The rotation of the tension adjusting nut 98 either draws the threaded rod 96 into the nut 98 and tightens the left rear cable strand 66 (and the whole cable system), or moves the threaded rod 96 away from the tension adjusting nut 98 and loosens the left rear cable strand 66 (and the whole cable system).
The parking brake lever 48 is movable from a released position where no increased tension is applied to the cable system 46, and can move to subsequent positions of ever increasing tension applied to the cable system, which occurs when the lever is moved upwardly with respect to the position shown in FIG. 1.
In assembling the park brake cable system 46, the tension of the rear left 66 and right 68 cable strands and the front cable strand 52 are very important. It is important to note in
After the cable system 46 is initially assembled into the structure shown in
In
This increased tension level is maintained until, as shown in
As shown in
In summary,
Opposing cantilever springs 12 are formed in the top surface of the clip connector 104. The cantilever springs 112 extend longitudinally along the length of the clip connector. Each of the springs is a cantilever, with the free end 114 of each of the springs 112 being bent to extend slightly into the cavity 106 of the clip connector 104 for purposes described below. Each of the ends 115 of the clip connector 104 are crimped inwardly to form an abutment surface 116 against which the end bead of a cable strand engages. The abutment surface 116 keeps the end bead from exiting the clip connector 104 through either end.
A radial slot 118 is formed through the clip connector 104 near its first end 102 and adjacent to the free end 114 of the cantilever spring member 112. See
The shear member 100 is shown in
The stress riser 126 is on the front surface of the shear tab 124 and is designed to create a calculated shear force necessary to shear the shear tab 124 from the clamp when it is positioned through the wall of the clip connector. The sheer force is applied by the cable end in step three of the method described above. The necessary shear force is related to the dimensions of the stress riser 126, the material used in the shear member 100, and the length of connection of the shear tab 124 to the main body 122. A desired shear strength is 160 to 250 pounds. The shear member 100 is made of a rigid glass-filled plastic with a high flexural strength or a high modulus of elasticity, and the shear tab 124 is typically the same material.
As shown in
The bead 90 on the first end of the right rear cable strand 68 is inserted into the clip connector 104 through the wide portion 110 in the bottom slot 108 and pulled against the crimping 116 at the second end of the clip connector, and is held in place at that position by the cantilever spring 112 to minimize or prohibit axial movement of the end bead 90 within the cavity 106 of the clip connector 104.
In
In this third embodiment, the clip connector 140 is used in conjunction with the rear left cable strand 66 and the Z-shaped equalizer structure 142. The Z-shaped equalizer 142 has an elongated body with a first end 144 forming an upwardly extending L-shape, and a second end 146 forming a downwardly extending L-shape. The first end 57 of the front conduit 56 is fixed to the frame 50 of the vehicle, and the second end 58 of the front conduit 56 abuts against the upwardly extending L-shaped leg at the first end 144 of the equalizer 142. A normal cable end connector 148 is used to connect the end bead 54 of the front cable strand 52 with the end bead 90 of the rear right cable strand 68. The rear left cable strand 66 is attached to the downwardly extending portion of the second end 146 Z-shaped equalizer structure 142 by the clip connector 140. The threaded rod 96 is positioned through an aperture 150 formed in the second end 146 of the equalizer structure 142, through the interior cavity of the clip connector 140, and through an aperture 152 (
In more detail, as shown in
As with the first embodiment, the park brake cable system allows the proper tensioning of the cable system to minimize voids and accelerate the creep lengthening of the cable, which helps enhance performance of the park brake cable system in the vehicle, as described above with respect to the first embodiment.
After the park brake cable system has been assembled in the vehicle, the cable system is initially tensioned from having no brake engagement to having brake engagement by actuating the threaded fastener 156 on the end of the threaded rod 96. This can be done with a socket wrench 172, or other type of wrench, as shown in FIG. 20. The threaded fastener 156 is tightened to draw the threaded rod 96 towards the equalizer structure 142, which in turn moves the brake pad towards the brake drum in the left 84 and right 74 brake assemblies. When the left and right brake pads engage the respective brake drums in the left 84 and right 74 brake assemblies, the brake assemblies are engaged. The threaded fastener 156 continues to be tightened to apply more tension load on the park brake cable system.
At the calculated tension load, sufficient shear force has been developed by the threaded fastener 156 on the shear plate 154 to break the shear plate at the attachment sections 162 from the wall of the axial bore of the collar 158. This allows the fastener 156 to exit the tool 172 and pass through the collar 158 to engage the second end 146 of the equalizer structure 142 on top of the washer 170 and the shear plate 154. See FIG. 21. The washer 170 helps evenly distribute the tension load on the shear plate 154. The distance that the disk moves is the relief distance which de-tensions the cable system sufficiently to disengage the brake pads from the hubs the right amount, with the desired residual tension remaining in the cable system.
This method requires only three steps in assembling and setting the park brake cable system. The first is tightening the threaded fastener to tension the cable system sufficiently to eliminate or reduce voids and accelerate the creep of the cable. The second step is increasing the tension by further actuating the threaded fastener 156 until the shear plate 154 severs. The shear force required to brake the shear plate 154 is calculated so as to allow the user to generate sufficiently high tension during tightening of the threaded fastener 156 to adequately minimize voids and accelerate the creep of the cable system. The third step in the first embodiment of actuating the brake lever is thus not required in this embodiment. This embodiment automatically sets the proper tension and cannot be over-adjusted because the fastening member is pulled inside the connector clip 140.
An alternative to the third embodiment is shown in FIG. 24. The shear plate 176 in the fourth embodiment 175 shown in
The third and fourth embodiments of the present invention have the additional advantage over the first and second embodiments in that they do not require a worker to first apply tension to the system by turning the tension adjustment nut and then separately break the shear tab by activating the brake lever. Instead, the third and fourth embodiments simply require a worker to tighten the tension adjusting nut sufficiently to brake the shear plate, which is done all in one operation and saves time and thus manpower.
An application of the fourth embodiment of the present invention is shown in
Schematically, the left rear cable strand 202 is attached to one end 206 of the equalizer structure and the right rear cable strand 204 is attached to the opposite end 208 of the equalizer structure, with the front cable strand 196 attached to the equalizer 200 assembly mid-way between the two. The second ends of the left rear 202 and right rear 204 cable strands are attached to the left rear 210 and right rear 212 brake assemblies, respectively, as shown. The right rear 212 and left rear 210 brake assemblies work as described above. The equalizer 200 can be a rigid bar. The front cable strand 196 and the left 202 and right rear 204 cable strands pass through conduits 214 as in the previous embodiments. The center pull system 190 does not rely on reaction conduit force balancing, however.
The method of properly tensioning the park brake cable system 190 of this embodiment includes the steps of assembling the park brake cable system as described above such that the brake actuation lever 192 is in its release position (
Step 3 requires the tension adjusting member 186 to continue to be actuated until the tension force in the cables overcome the force required to cause a shear plate 176 to fracture and separate from the collar 184. This tension load is approximately 300 to 600 pounds, which is sufficient to overcome the shear strength of the shear plate 176. The cable tension, once the shear plate 176 disconnects, pulls the tensioning member 186 into the collar 184 and out of engagement with the tool used to tighten the adjusting member 186. The tension member 186 moves a specific distance to the end of the collar 184 and rests against the brake actuation lever 192. See
The connector clip of the present invention works in the described cable systems to effectively apply sufficient tension to remove voids and activate cable stretching. In addition, the shear member acts as a “fuse” to allow the proper offset of tension when a critical high tension level has been reached. The residual tension in the system is sufficient to provide consistent park brake performance.
Presently preferred embodiments of the present invention and many of its improvements have been described with a degree of particularity. The previous description is of a preferred example for implementing the invention, and the scope of the invention should not necessarily be limited by this description. The scope of the present invention is defined by the scope of the following claims.
Claims
1. A park brake cable system comprising:
- a brake actuation lever;
- a connector clip having a first end and a second end, and including a shear member having a shear failure force, positioned between the first and second ends of said connector clip;
- a brake assembly;
- a front cable strand having a first and second ends, the first end attached to the brake actuation lever, and the second end engaging the shear member on the connector clip;
- a first rear cable strand having a first end and a second end, the first end attached to the second end of the connector clip and the second end attached to the brake assembly; and
- tensioner means attached in a tension force transmitting relationship with the front cable strand and the first rear cable strand, creating a continuous connection from the brake actuation lever to the brake assembly;
- wherein applying tension to the front and first rear cable strands by the tensioner means creates at least the shear failure force to cause the second end of the front cable strand to separate the shear member from the connector clip and move to the first end of the connector clip, and maintain the continuous connection from the brake actuation lever to the brake assembly.
2. The park brake cable system as defined in claim 1 wherein actuating said tensioner means develops a first tension level prior to separating the shear member from the connector clip, and a second residual tension level after separating the shear member from the connector clip.
3. A park brake cable system as defined in claim 1 wherein said connector clip includes a main body having an interior cavity, and open first and second ends, and wherein at least a portion of the shear member extends across a portion of the interior cavity.
4. A park brake cable system as defined in claim 3 wherein said at least a portion of the shear member is a tab.
5. A park brake cable system as defined in claim 4 wherein the tab includes a stress riser.
6. A park brake cable system as defined in claim 4 wherein said tab has a front face and a rear face, the front face (i) facing said first end of the first rear cable strand and (ii) having a stress riser disposed thereon, and the rear face being opposite said front face.
7. A park brake cable system as defined in claim 4 wherein said tab has a front face and a rear face, the rear face (i) facing away from said first end of the first rear cable strand and (ii) having a stress rise disposed thereon, and the front face being opposite said rear face.
8. A park brake cable system as defined in claim 3 wherein:
- said shear member has a partially cylindrical body and said at least a portion of the shear member defines a tab extending orthogonally inwardly;
- said main body of the connector clip defines an outer surface and includes an aperture formed through said main body from said outer surface to said interior cavity; and
- said partially cylindrical body of the shear member mounts on said outer surface and said tab extends through said aperture to extend across at least a portion of the interior cavity.
9. A park brake cable system as defined in claim 3 wherein:
- the shear member and the connector clip are integrally formed;
- said main body is a generally cylindrical body defining a bore therethrough and having an interior side wall; and
- said at least a portion of the shear member comprises a shear disk, the shear disk being attached to said interior side wall and extending across said bore.
10. A park brake cable system as defined in claim 9 wherein said shear disk is attached at selected locations along said side wall.
11. A park brake cable system as defined in claim 9 wherein said shear disk is attached continuously along said side wall.
12. A park brake cable system as defined in claim 9 wherein said shear disk extends radially across said interior cavity.
13. A park brake cable system as defined in claim 9 wherein said shear member defines a stress riser therein.
14. A park brake cable system as defined in claim 9 wherein:
- said shear disk has a front face and a rear face; and
- said front face defines a stress riser therein.
15. A park brake cable system as defined in claim 9 wherein:
- said shear disk has a front face and a rear face; and
- said rear face defines a stress riser therein.
16. A park brake cable system as defined in claim 1 wherein said connector clip comprises an elongated body defining an interior cavity and having first and second ends.
17. The park brake cable system of claim 16, wherein the first and second ends of the connector clip are open.
18. The park brake cable system of claim 17, wherein the second end of the front cable strand and the first end of the first rear cable strand have beads attached thereto, and wherein a width of each bead is greater than a diameter of the respective front or first rear cable strand to which the bead is attached.
19. The park brake cable system of claim 18, wherein the elongated body includes a slot, the slot (i) extending longitudinally from the first end to the second end of the elongated body, (ii) having a first width proximate either of the first and second ends that is less than the width of the beads, and (ii) having a second width proximate a central portion of the elongated body that is greater than the width of the beads.
20. The park brake cable system of claim 18, wherein the elongated body is crimped inwardly proximate at least one of the first and second ends to form an abutment surface against which one of the beads is engaged.
21. The park brake cable system of claim 16, wherein at least a portion of the shear member extends into said interior cavity.
22. The park brake cable system of claim 21, wherein the portion of the shear member comprises a tab.
23. The park brake assembly of claim 2, wherein the first tension level ranges from 160 to 250 pounds.
24. The park brake assembly of claim 2, wherein the second residual tension level ranges from 90 to 130 pounds.
25. The park brake assembly of claim 1, wherein the distance the second end of the front cable strand moves ranges from 13 to 25 millimeters.
26. The park brake cable system of claim 1, wherein the park brake cable system further comprises:
- an equalizer structure; and
- a second rear cable strand, the second rear cable stand having first and second ends;
- wherein the brake assembly includes (i) a rear left brake, and (ii) a rear right brake, the first end of the second rear cable strand being attached to the equalizer, and the second end of the second rear cable strand being attached to one of the rear left brake and the rear right brake, the second rear cable end of the first rear cable strand being attached to the other of the rear left brake and the rear right brake.
27. The cable system as defined in claim 26 wherein said tensioner means is positioned on said equalizer.
28. The cable system as defined in claim 26 wherein said tensioner means is positioned on said brake actuation lever.
29. A park brake cable system comprising:
- a brake actuation lever;
- a connector clip having a first connector clip end and a second connector end, and including a shear member having a shear failure force, positioned between the first and second connector ends;
- a brake assembly;
- a front cable strand having a first and second front cable ends, the first front cable end being attached to the brake actuation lever, and the second front cable end engaging one of the shear member and the first connector clip end;
- a first rear cable strand having a first rear cable end and a second rear cable end, the first rear cable end attached to one of the shear member and the second connector clip end, only one of the second front cable end and the first rear cable end being attached to the shear member; and
- a tensioner means attached in a tension force transmitting relationship with the front cable strand and the first rear cable strand, creating a continuous connection from the brake actuation lever to the brake assembly;
- wherein applying tension to the front and first rear cable strands by the tensioner means creates at least the shear failure force to cause the one of the second front cable end and the first rear cable end attached to the shear member (i) to separate the shear member from the connector clip and (ii) move to one of the first and second connector ends respectively, maintaining a continuous connection from the brake actuation lever to the brake assembly.
30. A park brake cable system as defined in claim 29 wherein said connector clip includes a main body having an interior cavity, and open first and second connector ends, and wherein at least a portion of the shear member extends across a portion of the interior cavity.
31. A park brake cable system as defined in claim 30 wherein said at least a portion of the shear member is a tab.
32. A park brake cable system as defined in claim 31 wherein the tab includes a stress riser.
33. A park brake cable system as defined in claim 31 wherein said tab has a front tab face and a rear tab face, the front tab face (i) facing said first rear cable end and (ii) having a stress riser disposed thereon, and the rear tab face being opposite said front tab face.
34. A park brake cable system as defined in claim 30 wherein:
- said shear member has a partially cylindrical body and said at least a portion of the shear member defines a tab extending orthogonally inwardly;
- said main body of the connector clip defines an outer surface and includes an aperture formed through said main body from said outer surface to said interior cavity; and
- said partially cylindrical body of the shear member mounts on said outer surface and said tab extends through said aperture to extend across at least a portion of the interior cavity.
35. A park brake cable system as defined in claim 30 wherein:
- the shear member and the connector clip are integrally formed;
- said main body is a generally cylindrical body defining a bore therethrough and having an interior side wall; and
- said at least a portion of the shear member comprises a shear disk, the shear disk being attached to said interior side wall and extending across said bore.
36. A park brake cable as defined in claim 35, wherein said shear disk is attached at selected locations along said side wall.
37. A park brake cable as defined in claim 36, wherein said shear disk is attached continuously along said side wall.
38. A park brake cable as defined in claim 35, wherein said shear disk defines a stress riser therein.
39. A park brake cable system as defined in claim 29 wherein said connector clip comprises an elongated body defining an interior cavity.
40. The park brake cable system as defined in claim 29 wherein actuating said tensioner means develops a first tension level prior to separating the shear member from the connector clip, and a second residual tension level after separating the shear member from the connector clip.
41. The park brake assembly of claim 40, wherein the first tension level ranges from 160 to 250 pounds.
42. The park brake assembly of claim 40, wherein the second residual tension level ranges from 90 to 130 pounds.
43. The park brake assembly of claim 29, wherein the one of the second front cable end and the first rear cable end that is attached to the shear member moves a distance ranging from 13 to 25 millimeters.
44. The park brake cable system of claim 29, wherein the park brake cable system further comprises:
- an equalizer structure; and
- a second rear cable strand, the second rear cable stand having first and second ends;
- wherein the brake assembly includes (i) a rear left brake, and (ii) a rear right brake, the first end of the second rear cable strand being attached to the equalizer, and the second end of the second rear cable strand being attached to one of the rear left brake and the rear right brake, the second rear cable end of the first rear cable strand being attached to the other of the rear left brake and the rear right brake.
45. The cable system as defined in claim 44 wherein said tensioner means is positioned on said equalizer.
46. The cable system as defined in claim 44 wherein said tensioner means is positioned on said brake actuation lever.
47. A park brake cable system comprising:
- a brake actuation lever;
- a connector clip having a first end and a second end, and including a shear member having a shear failure force, positioned between the first and second ends of said connector clip;
- a brake assembly;
- a front cable strand having a first and second ends, the first end attached to the brake actuation lever, and the second end engaging the first end on the connector clip;
- a first rear cable strand having a first end and a second end, the first end attached to the shear member of the connector clip and the second end attached to the brake assembly; and
- tensioner means attached in a tension force transmitting relationship with the front cable strand and the first rear cable strand, creating a continuous connection from the brake actuation lever to the brake assembly;
- wherein applying tension to the front and first rear cable strands by the tensioner means creates at least the shear failure force to cause the first end of the first rear cable strand to separate the shear member from the connector clip and move to the second end of the connector clip, and maintain the continuous connection from the brake actuation lever to the brake assembly.
48. A park brake cable system as defined in claim 47 wherein said connector clip includes a main body having an interior cavity, and open first and second ends, and wherein at least a portion of the shear member extends across a portion of the interior cavity.
49. A park brake cable system as defined in claim 48 wherein said at least a portion of the shear member is a tab.
50. A park brake cable system as defined in claim 49 wherein the tab includes a stress riser.
51. A park brake cable system as defined in claim 49 wherein said tab has a front face and a rear face, the front face (i) facing said first end of the first rear cable strand and (ii) having a stress riser disposed thereon, and the rear face being opposite said front face.
52. A park brake cable system as defined in claim 48 wherein:
- said shear member has a partially cylindrical body and said at least a portion of the shear member defines a tab extending orthogonally inwardly;
- said main body of the connector clip defines an outer surface and includes an aperture formed through said main body from said outer surface to said interior cavity; and
- said partially cylindrical body of the shear member mounts on said outer surface and said tab extends through said aperture to extend across at least a portion of the interior cavity.
53. A park brake cable system as defined in claim 48 wherein:
- the shear member and the connector clip are integrally formed;
- said main body is generally cylindrical body defining a bore therethrough and having an interior side wall; and
- said at least a portion of the shear member comprises a shear disk, the shear disk being attached to said interior side wall and extending across said bore.
54. A park brake cable system as defined in claim 53 wherein said shear disk is attached at selected locations along said side wall.
55. A park brake cable system as defined in claim 53 wherein said shear disk is attached continuously along said side wall.
56. A park brake cable system as defined in claim 53 wherein said shear member defines a stress riser therein.
57. A park brake cable system as defined in claim 47 wherein said connector clip comprises an elongated body defining an interior cavity.
58. The park brake cable system as defined in claim 47 wherein actuating said tensioner means develops a first tension level prior to separating the shear member from the connector clip, and a second residual tension level after separating the shear member from the connector clip.
59. The park brake assembly of claim 58, wherein the first tension level ranges from 160 to 250 pounds.
60. The park brake assembly of claim 58, wherein the second residual tension level ranges from 90 to 130 pounds.
61. The park brake assembly of claim 47, wherein the distance the first end of the of the first rear cable strand moves ranges from 13 to 25 millimeters.
62. The park brake cable system of claim 47, wherein the park brake cable system further comprises:
- an equalizer structure; and
- a second rear cable strand, the second rear cable stand having first and second ends;
- wherein the brake assembly includes (i) a rear left brake, and (ii) a rear right brake, the first end of the second rear cable strand being attached to the equalizer, and the second end of the second rear cable strand being attached to one of the rear left brake and the rear right brake, the second rear cable end of the first rear cable strand being attached to the other of the rear left brake and the rear right brake.
63. The cable system as defined in claim 62 wherein said tensioner means is positioned on said equalizer.
64. The cable system as defined in claim 62 wherein said tensioner means is positioned on said brake actuation lever.
2821091 | January 1958 | Benner |
3237977 | March 1966 | Batchelder |
3513719 | May 1970 | Tschanz |
4020713 | May 3, 1977 | Cntley et al. |
4057135 | November 8, 1977 | Mori |
4174099 | November 13, 1979 | Yamasaki |
4227594 | October 14, 1980 | Kluger |
4271718 | June 9, 1981 | Bopp et al. |
4374597 | February 22, 1983 | Mochida |
4378713 | April 5, 1983 | Haskell et al. |
4407167 | October 4, 1983 | Koukal et al. |
4412458 | November 1, 1983 | Derringer |
4543849 | October 1, 1985 | Yamamoto et al. |
4569112 | February 11, 1986 | Dussault |
4624155 | November 25, 1986 | Wing |
4658668 | April 21, 1987 | Stocker |
4838109 | June 13, 1989 | Stewart |
4887705 | December 19, 1989 | Solano et al. |
5016490 | May 21, 1991 | Jaksic |
5080434 | January 14, 1992 | Locher |
5086662 | February 11, 1992 | Tayon et al. |
5144856 | September 8, 1992 | Roca |
5203068 | April 20, 1993 | Siring |
5211071 | May 18, 1993 | Hedstrom |
5235870 | August 17, 1993 | Hedstrom |
5386887 | February 7, 1995 | Hilgert et al. |
5662004 | September 2, 1997 | Osborn et al. |
5813290 | September 29, 1998 | Takahashi et al. |
5816109 | October 6, 1998 | Dege |
20020084154 | July 4, 2002 | Peter |
41 09 887 | March 1991 | DE |
42 41 389 | December 1992 | DE |
4109887 | July 1996 | DE |
196 18 421 | May 1997 | DE |
2 260 588 | April 1993 | GB |
2-159408 | June 1990 | JP |
3-90461 | April 1991 | JP |
- Halliday Resnick Physics Parts I & II, David Halliday & Robert Resnick, John Wiley & Sons, Inc., 1967, pp. 87-90.
- Webster's II New Riverside University Dictionary, The Riverside Publishing Co., 1994, pp 198 and 199.
- Standard Handbook of Machine Design, Joseph E. Shigley & Charles R. Mischke, McGraw-Hill Book Co., pp. 7.34-7.38.
- Handbook of tables for Applied Engineering Science, 2nd Ed., CRC Press 1976, pp 103-115.
- Gregory H. Petrak, Affidavit of Gregory H. Petrak, Nov. 25, 2003, 8 pages.
Type: Grant
Filed: Nov 16, 1999
Date of Patent: Nov 1, 2005
Patent Publication Number: 20020011129
Inventor: Gregory H. Petrak (Golden, CO)
Primary Examiner: Vinh T. Luong
Attorney: Dorsey & Whitney LLP
Application Number: 09/441,628