Brake Pedal Positioning Mechanism

1. Field of the Invention

The present invention relates to a vehicle parking brake pedal positioning mechanism for locking a parking brake pedal in an actuated condition against pivotal movement toward a released position.

2. Description of the Prior Art

Certain vehicle parking brake pedal positioning mechanisms include a parking brake pedal pivotally mounted on a frame for movement between an actuated condition and a released position. The brake pedal is connected by a suitable flexible cable or cables to the associated vehicle parking brakes to maintain an actuated brake condition when the pedal is moved to its actuated condition. The actuated pedal condition prevents vehicle movement during parking when the driver leaves the vehicle or during extended periods of standing while the driver remains in the vehicle. The pedal is usually detented in the actuated condition by a pawl and ratchet arrangement. A flexible cable is conventionally incorporated to selectively release the pawl and ratchet engagement and to thereby allow the pedal to return to its released position so that normal vehicle operation may then take place.

Parking brake pedals of the above described type move rapidly from the actuated condition to the released position due to tension of the associated brake cables in the actuated condition. The pedal rapidly impacts a suitable stop upon reaching the released position and thereby causes a relatively loud banging sound that can startle a vehicle passenger or driver while causing an impact loading of the stop and the pedal portion which engages the stop. Also, the pawl and ratchet locking of this type of parking brake pedal mechanism allows positioning of the brake pedal in only a limited number of positions. The brake pedal position which corresponds to a fully actuated parking brake condition without over stressing the brake cables may correspond to a parking pedal position intermediate two adjacent positions in which the pawl and ratchet are capable of positioning the pedal. Consequently, the parking brake pedals will be only partially actuated if the brake pedal is detented in one of these positions or the associated brake cables will be over stressed and elastically and/or plastically strained if the pedal is detented in the other position to fully actuate the parking brakes.

It should be understood that locking mechanisms of the infinite position type have heretofore been utilized with clamps for holding a workpiece to be machined. See, for example, U.S. Pat. No. 2,603,323.

An object of the present invention is to provide an improved vehicle parking brake pedal positioning mechanism for positioning a parking brake pedal in an actuated condition against pivotal movement toward a released position by an infinite position locking action.

In carrying out the above object as well as other objects of the invention, the parking brake pedal positioning mechanism includes a frame that pivotally mounts a pedal and a locking member for movement about a common pivotal axis with respect to the frame and with respect to each other. The frame includes a first cam surface extending about the pivotal axis and including a portion having increasing radii therefrom moving in a direction corresponding to the brake pedal movement from the released position to the actuated condition. Likewise, the locking member includes a second cam surface extending about the pivotal axis and including a portion having increasing radii therefrom in the same direction as the first cam surface portion on the frame. A slide is mounted for rotation with the brake pedal and for sliding movement with respect thereto and includes first and second opposite ends respectively engaged in a slidable manner with the first and second cam surface portions on the frame and the locking member. The slidable engagement of the slide ends with the first and second cam surface portions locks the slide therebetween to provide an infinite position locking action for positioning the brake pedal in the actuated condition against movement toward the released position. A spring bias of the locking member normally biases it about the pivotal axis in a direction so as to maintain the slidably engaged condition between its second cam surface portion and the second end of the slide. The locking member is selectively moved in the other direction about the pivotal axis to release the slide from its locked condition so as to thereby permit the pedal to move to its released position.

Preferably, the frame of the pedal positioning mechanism has a plate-like construction and is stamped to form a depression with a round aperture concentric with the pivotal axis. A first round portion of the depression immediately adjacent the round aperture defines the first cam surface and is located in an eccentric relationship with respect to the pivotal axis so as to include the cam surface portion that has increasing radii from the axis in a direction corresponding to the pedal movement to the actuated condition. A second round portion of the frame depression is located immediately adjacent the first round portion on the opposite side thereof from the round aperture and is concentric with the pivotal axis. The locking member has a circular configuration and is received within the second round frame depression portion so as to pivot about the pivotal axis. A round aperture of the locking member is eccentric with respect to the pivotal axis and defines the second cam surface portion. The frame depression is closed by a plate that slidably engages the locking member in an axial relationship to retain the locking member within the depression. A round aperture of the plate is aligned with the round aperture of the depression and cooperates therewith in pivotally supporting a journal which is fixed to the pedal. A slot in the journal receives the slide whose opposite ends are slidably engaged with the cam surface portions.

The spring bias of the locking member is provided by a spring extending between the locking member and the pedal in the form of a first elongated leaf spring. One end of this leaf spring is hooked to receive a pin carried by the locking member and the other end of the spring is riveted to the pedal. A foot actuated pad pivoted to the pedal attaches one end of a second elongated leaf spring whose other end is connected to the first leaf spring.

During pedal movement to the actuated condition, the foot pad is depressed and the first leaf spring exerts a bias on the locking member. Pivoting of the locking member then proceeds in the same direction as the pedal but for a greater extent so as to maintain an engaged condition between the second cam surface portion of the locking member and the second end of the slide. With the pedal in the actuated condition, the foot pad is operated so as to pull on the first leaf spring through the second leaf spring and thereby pivot the locking member in a manner that releases the slide from its locked relationship between the cam surface portions. As the slide is released, the operator's foot counteracts the forces exerted on the pedal by the associated vehicle brake cable so that the locking member movement is not restrained by these forces acting between the slide ends and the cam surface portions. The locking member movement positions the second cam surface portion with respect to the first cam surface portion to allow pivoting of the slide as the pedal moves to the released position. A central depression and upper and lower projections on the foot pad facilitates operation of the pad. Between the slide and the foot pad, the pedal has a channel-shaped cross section that receives the first and second leaf springs. The first leaf spring which biases the locking member has a longer length than the second leaf spring that connects the foot pad to the first leaf spring.

The objects, features and advantages of the present invention are readily apparent from the following detailed description of the preferred embodiment taken in connection with the accompanying drawings.

FIG. 1 is a side elevation view of a vehicle parking brake pedal positioning mechanism that embodies the present invention, with a pedal of the mechanism shown in a solid line indicated released position, and with the pedal also shown in a phantom line indicated actuated condition;

FIG. 2 is a partially broken away elevation view taken along line 2--2 of FIG. 1 looking forwardly with respect to the vehicle on which the positioning mechanism is mounted.

FIG. 3 is an enlarged sectional view through the mechanism taken generally along line 3--3 of FIG. 1;

FIG. 4 is a side view of the positioning mechanism taken partially in section along line 4--4 of FIG. 3;

FIG. 5 is a sectional view through the mechanism taken along line 5--5 of FIG. 4; and

FIG. 6 is a sectional view of the mechanism taken along line 6--6 of FIG. 1 to show the mounting of a foot pad on the mechanism pedal.

Referring to FIGS. 1 and 2 of the drawings, a vehicle parking brake pedal positioning mechanism according to the present invention is generally indicated by reference numeral 10 and includes a stamped steel frame 12 mounted on a body panel 14 by a plurality of threaded stud and nut mounts 16. A pedal 18 of the mechanism is pivotally mounted on frame 12 for movement about a pivotal axis A between the solid line indicated released position shown and the phantom line indicated actuated condition. As seen with particular reference to FIG. 1, an upper arm 20 of the pedal 18 is biased in a counterclockwise direction about axis A by a spring 21 extending between the frame 12 and the pedal arm. The pedal arm 20 supports a pin 22 connected to the upper end of an attachment member 24. A parking brake cable 26 of the mechanism includes a wire 28 connected to the lower end of attachment member 24 and received within a sheathing 30 of the cable. An end fitting 32 of the cable sheathing is mounted on the mechanism frame 12 so that depression of the pedal 18 from the solid line released position to the phantom line actuated condition pulls the cable wire 28 through the sheathing and thereby actuates the associated vehicle parking brakes. A lower end 34 of the pedal 18 mounts a foot pad 36 by a pintle 38 for pivotal movement. The pedal 18 is depressed by an operator's foot pressing down on the pad 36 and is released from the actuated condition by foot actuated pivoting of the pad in a manner that will be more fully hereinafter described.

With reference to FIGS. 3 and 5, the mechanism frame 12 has a plate-like construction and includes a stamped depression generally indicated by 40. A round aperture 42 of the frame depression 40 is concentric with the pivotal axis A and is located axially therealong immediately adjacent a first round depression portion 44. Depression portion 44 defines a first round cam surface 46 that faces inwardly toward the pivotal axis A and extends completely thereabout in an eccentric relationship with respect thereto as seen in FIG. 4. As best seen in FIG. 3, depression 40 also includes a second round depression portion 48 located immediately adjacent the first depression portion 44 along the pivotal axis A on the opposite side of the first depression portion from the depression aperture 42. Depression portion 48 receives a locking member 50 of a plate-like construction with a round configuration having an outer edge 52 slidably engaged with this round depression portion so that the locking member pivots about the axis A. Locking member 50 includes a second cam surface 54 that defines a round aperture through the locking member. The second cam surface 54 extends completely about pivotal axis A in an eccentric relationship with respect thereto and with respect to the first cam surface 46 of the frame when the locking member is in the position shown in FIG. 4. A plate 56, FIG. 3, is secured to the frame 12 in any suitable manner such as by welding and covers the frame depression 40 so as to engage the locking member in an axial relationship that maintains the locking member within the depression supported for pivotal movement about axis A. Plate 56 is stamped to define a round aperture 58 concentric with the pivotal axis A and cooperable with the depression aperture 42 to pivotally support a journal 60.

As seen by reference to FIGS. 3 and 5, the journal 60 has a splined end 62 received by an annular splined member 64 mounted on the pedal 18 in a suitable manner such as by welds 66. A bolt 68 concentric with the pivotal axis A extends through an aperture 70 of the pedal and is threaded into the journal end 62 so as to maintain the interengaged relationship of the journal with the splined member 64 in a manner that causes the journal to rotate with the pedal. An enlarged end 72 of journal 60 extends through the aperture defined by the second cam surface 54 of locking member 50 to be rotatably supported by the depression aperture 42 about axis A. An intermediate portion 74 of the locking member located between its splined end 62 and its enlarged end 72 is rotatably supported within the plate aperture 58. A slot 75 in the enlarged journal end 72 extends through the pivotal axis A and has opposite ends that open toward the cam surfaces 46 and 54. Journal slot 75 receives a slide 76 which rotates with the pedal but is slidable relative thereto in a radial direction with respect to the pivotal axis A. Slide 76 includes first and second opposite ends 78 and 80 that are axially offset with respect to the pivotal axis A so as to respectively engage first and second cam surfaces 46 and 54 in a slidable manner. First slide end 78 slidably engages the first cam surface 46 of the frame at a portion 46a thereof, FIG. 4, which has increasing radii from the pivotal axis A in a clockwise direction corresponding to the direction of brake pedal movement from the released position toward the actuated condition. Likewise, the second slide end 80 slidably engages the second cam surface 54 of the locking member at a portion 54a thereof that also has increasing radii from the pivotal axis A in a clockwise direction corresponding to the direction of brake pedal movement from the released position to the actuated condition.

As seen by combined reference to FIGS. 2 and 4, the locking member 50 carries a pin 82 that extends outwardly through an arcuate slot 84 in the plate 56 that maintains the locking member within the frame depression 40. A first elongated leaf spring 86 of the mechanism has one end 88 with a hook shape that receives pin 82 on the locking member. Another end 90 of the leaf spring 86 is secured to the pedal 18 adjacent foot pad 36 in a suitable manner such as by the rivet 92 shown in FIG. 1. A second elongated leaf spring 94 of the mechanism has one end 96 secured to an intermediate portion of spring 86 in a suitable manner such as by the rivet 98. Another end 100 of second leaf spring 94 is secured to a bent flange 102 of the pedal foot pad 36 by a suitable connection such as rivet 104. The pedal 18, as seen by particular reference to FIG. 6, has a channel shape taken in cross section so as to receive the two leaf springs 86 and 94. Leaf spring 86 has a longer length than the leaf spring 94 and extends between pedal 18 and locking member 50 so as to bias the locking member in a clockwise direction when the pedal is in the solid line released position of FIG. 1. Leaf spring 94 connects the foot pad 36 with the longer leaf spring 86 so as to permit actuation of the pad with the pedal in the phantom line actuated condition to release the mechanism for return of the pedal to the released position. Upper and lower projection 106 and 108 of the foot pad and an intermediate depression 110 are utilized to facilitate the actuation of foot pad 36 in a manner that will be more fully hereinafter discussed.

Operation of the brake pedal positioning mechanism 10 will now be described with reference to FIGS. 1 and 4 while keeping in mind the structure previously discussed. With the brake pedal 18 in the solid line released position of FIG. 1, the first elongated leaf spring 86 biases the mechanism locking member 50, FIG. 4, in a clockwise direction about pivotal axis A such that the second cam surface portion 54a is maintained in engagement with the second end 80 of the slide 76. Cam surface portion 54a has increasing radii in this clockwise direction and, consequently, decreasing radii in the counterclockwise direction so that its engagement with the slide end 80 also tends to move the slide with respect to the journal 60 in the direction of arrow C. As a result, the first slide end 78 is maintained in engagement with the first cam surface portion 46a of the stationary frame 12. An operator desiring to actuate the associated vehicle parking brakes depresses the pedal 18 by foot engagement with the upper projection 106 of the foot pad 36. During such depression, the pad 36 is at its limit of counterclockwise pivotal movement about pintle 38 due to engagement of respective flanges 112 and 114 of the pedal and the pad, see FIG. 6. Slide 76 is rotated in a clockwise direction with pedal 18 as the pedal is depressed to its actuated condition and the first slide end 78 then moves along the first cam surface portion 46a in a clockwise direction about pivotal axis A. Cam surface portion 46a has increasing radii about this pivotal axis in the clockwise direction and allows the slide 76 to move in the direction of arrow C with respect to journal 60 as the pedal depression takes place. Locking member 50 is moved by the bias of spring 86 during the pedal depression so as to move the slide 76 in the direction of arrow C as permitted by the cam surface portion 46a. Sliding movement of the slide 76 in the direction of arrow C is actuated by the second cam surface portion 54a of locking member 50. This cam surface portion 54a has decreasing radii in the counterclockwise direction about pivotal axis A and, under the bias of the spring 86, the locking member 50 rotates further in the clockwise direction during the pivotal depression than the pedal such that the slide end 80 moves relative to cam surface portion 54a in a counterclockwise direction. Consequently, the slide 86 moves in the direction of arrow C as the first end 78 of the slide moves in a clockwise direction along the first cam surface portion 46a.

Once the brake pedal 18 is moved to a fully actuated condition such that the parking brake cable 26 fully actuates the associated vehicle parking brakes, the positioning mechanism 10 locks the pedal in an infinite position manner against movement back toward the released position. This locking action in an infinite position fashion permits the pedal to fully actuate the brakes without over stressing the parking brake cable components. Forces of the parking brake tend to rotate the pedal 18 in a counterclockwise direction such that the slide 76 is biased so as to urge its first end 78 in a counterclockwise direction along the first cam surface portion 46a of the stationary frame. Movement of slide end 78 along cam surface portion 46a in this direction requires the slide 76 to move in the direction of arrow D, FIG. 4. However, for the slide 76 to move in the direction of arrow D requires slide end 80 to slide in a counterclockwise direction along the second cam surface portion 54a of the locking member. But the bias exerted on the locking member 50 by slide end 80 due to the pedal is in a clockwise direction that tends to move slide end 80 along cam surface portion 54a in a counterclockwise direction. the net effect is that the slide 76 is locked between the cam surface portions in an infinite position manner that prevents the pedal movement back toward the released position.

To release the pedal 18 for movement from its phantom line indicated actuated condition of FIG. 1 back toward its solid line indicated released position, an operator places his foot on the lower projection 108 of the foot pad 36 so as to rotate the foot pad in a clockwise direction about its pintle 38 to the clockwise extent of movement allowed by flanges 112 and 114. This movement causes the second leaf spring 94 to pull the first leaf spring 86 downwardly and to the right about its lower end 90 so as to pivot locking member 50 counterclockwise about pivotal axis A. Consequently, the second cam surface portion 54a moves counterclockwise with respect to the slide end 80 to permit the slide to move in the direction of arrow D, FIG. 4, such that slide end 78 can move counterclockwise along the first cam surface portion 54a of the frame and thereby allow movement of the pedal back toward its released position. During this releasing action, the operator's foot counteracts the forces exerted on the pedal 18 by brake cable 26. The slide ends 78 and 80 are thus not interengaged with the cam surface portions 46a and 54a by the brake cable forces and the locking member 50 is thus not restrained by these forces during its counterclockwise movement. As the pedal moves to the released position, the locking member 50 is rotated not only by the pedal rotation but by the relative movement between the locking member and the pedal caused by the foot pad actuation previously described. Consequently, the locking member 50 pivots for a greater extent of movement than does the pedal 18 during the movement between the released position and the actuated condition.

While a preferred embodiment of the parking brake pedal position mechanism has herein been described in detail, those skilled in the art will recognize various alternatives, embodiments and constructions for practicing the present invention as defined by the following claims.