The present invention relates to parking brakes for vehicles. In particular, this invention relates to parking brakes having quiet apply.
Conventional parking brakes have a ratchet and pawl arrangement for securing a parking brake in a locked position. The parking brake handle can be lifted towards the locked position, however it cannot be lowered without disengaging the ratchet and the pawl. A primary disadvantage of conventional brakes is that when the parking brake handle is lifted, the pawl is dragged across the teeth of the ratchet. This action creates a loud noise, which is in some cases undesirable.
In order to remove this noise, quiet apply parking brakes have been introduced. The quiet apply systems that are currently available tend to be complex and thus expensive to make and assemble. Therefore, it is desirable to have a quiet apply parking brake that is simple and effective.
The disadvantage of the prior art may be overcome by providing a parking brake assembly for a vehicle having a quiet apply.
According to one aspect of the invention, there is provided a parking brake for a vehicle. The parking brake has a mounting bracket having a stop. A handle assembly is pivotally mounted on the mounting bracket for rotation about a first axis between a brake release position to a brake applied position. A cam is pivotally mounted on the handle about a second axis offset from the first axis. The cam is biased to engage the stop. An actuator is operably connected to a clutch and the clutch frictionally engages the cam for selectively retaining the cam relative to the handle. Movement of the actuator responsively moves the clutch to release the cam enabling the cam to move relative to the handle. In response to releasing the actuator, the clutch retains the cam relative to the handle to prop the handle in a position between the brake release position and the brake applied position.
According to another aspect of the invention, there is provided a parking brake having a mounting bracket, a handle assembly and a locking mechanism. The mounting bracket has a stop. The handle assembly is pivotally mounted on the mounting bracket for rotation about a first axis. The handle is moveable between a brake applied position and a brake release position. The handle has an actuator. The locking mechanism has a cam pivotally mounted on the handle about a second axis offset from the first axis. The cam has a cam surface which varies radially from the second axis. The cam is biased to engage the stop. A clutch spring frictionally engages the cam and is operably connected to the actuator. Movement of the actuator in response to manual manipulation in a first direction responsively moves the clutch spring to decrease the frictional engagement, thereby enabling the cam to engage with the stop. In response to releasing the actuator, the clutch spring moves to increase frictional engagement with the cam thereby retaining the cam in a position to engage the stop.
Referring to
The mounting bracket 14 is a U-channel member having a longitudinal extent having upwardly extending walls 42 and 44. Cylindrical shaft 16 extends through apertures 24 in walls 42 and 44. An arm 19 extends coplanar with one of the walls 42, 44 and is offset longitudinally from shaft 16. Arm 19 supports a stop 18 that extends at least partly between the walls 42, 44 and is generally perpendicular to the walls 42, 44. Mounting bracket 14 is configured to attach to a vehicle (not shown) in any conventional manner.
Referring to
Locking or clutching mechanism 11 generally comprises a pivot pin 22, a rod 35, a clutch spring 30, a second spring 32 and a cam 34. Pivot pin 22 extends through apertures 46 in arm 13 so that pin 22 is spaced from shaft 16, defining a second axis of rotation. The cam 34 is fixedly mounted on the pivot pin 22. The cam 34 is seated forward and partially below the shaft 16 so as to not interfere with the pivoting of the handle assembly 12.
Rod 35 extends between the actuator or button 36 and clutch spring 30 to transmit movement of button 36 to the locking mechanism 11.
Cam 34 has a cam surface 37 on the peripheral extent thereof. The outline of the cam surface 37 has a varying radial extent from the second axis of rotation, the preferable shape being of an Archimedes spiral as shown in FIG. 6. The cam 34 has an arcuate cable guide (not illustrated).
Referring to
Second spring 32 extends between pivot pin 22 at aperture 23 and the arm 13 at aperture 52. Spring 32 is shaped to engage apertures 23 and 52 at opposite ends thereof. Spring 32 biases the cam 34 to rotate in the locking direction to engage the cam surface 37 with the stop 18.
Referring to
Now that the apparatus has been described, the mode of operation of the device will now be described.
Referring to
This particular mode is useful for a vehicle having a mechanical clutch. If the vehicle is stopped on an incline, a driver merely lifts on the handle 13 which engages the brakes. The driver is able to move the right foot from the brake pedal to the accelerator pedal without rolling backwards. Once the clutch is released to start engaging, the driver releases the handle 13 which immediately retracts to the brake release position, disengaging the brakes allowing the vehicle to proceed up the incline.
Referring to
To unlock the handle assembly 12, button 36 is pressed and held while the handle assembly 12 is counter rotated from the brake applied position to the brake release position. Pressing button 36 actuates rod 35 which rotates the clutch spring 30 in an unwinding sense so that the clutch spring 30 releases its grip on pivot pin 22. As the arm 13 is counter rotated, the engagement with the stop 18 will urge the cam 34 to return to its original position. The bias of second spring 32 is easily overcome by either the driver or the bias of the brake drums or calipers. Once the handle assembly 12 is fully rotated to the brake release position, the button 36 is released, re-establishing the frictional engagement between the clutch spring 30 and the cam 34.
Parking brakes of this type may be used on any type of vehicle. This would include golf carts and the like and any other type of vehicle that would benefit from having a parking brake.
Although the invention has been described with reference to certain specific embodiments, various modifications thereof will be apparent to those skilled in the art without departing from the scope of the invention as outlined in the claims appended hereto.
This application is a continuation-in-part of U.S. patent application Ser. No. 09/693,306, filed on Oct. 20, 2000, now abandoned, which claims the benefit and priority under 35 USC 119(e) of U.S. Provisional Application No. 60/160,857, filed on Oct. 21, 1999.
Number | Name | Date | Kind |
---|---|---|---|
4138905 | Konishi | Feb 1979 | A |
5247850 | Lenzke | Sep 1993 | A |
5448928 | Harger | Sep 1995 | A |
5509326 | Belmond | Apr 1996 | A |
5609066 | Bunker et al. | Mar 1997 | A |
5950496 | Rampp | Sep 1999 | A |
Number | Date | Country | |
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20030084743 A1 | May 2003 | US |
Number | Date | Country | |
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60160857 | Oct 1999 | US |
Number | Date | Country | |
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Parent | 09693306 | Oct 2000 | US |
Child | 10271234 | US |