Brakes – Vehicle – Railway
Reexamination Certificate
1998-09-18
2001-01-30
Mar, Michael (Department: 3613)
Brakes
Vehicle
Railway
C188S15300R, C188S107000, C074S089000
Reexamination Certificate
active
06179093
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates, in general, to a handbrake release mechanism for a parking brake assembly for a railway vehicle braking system and, more particularly, to a power source activated handbrake release mechanism for a parking brake assembly for a railroad vehicle braking system.
BACKGROUND OF THE INVENTION
As is generally well known in the railway industry, when railway cars are taken out of a train and parked at a siding or yard, the handbrake or parking brake on at least some of these cars is applied as a precaution against unwanted or unexpected movement of the cars. A typical railway car hand brake system normally consists of an apparatus for manually applying and biasing one or more brake shoes against the tread of one or more wheels of the railway car by either turning a hand wheel or pumping a ratchet handle on a hand brake mechanism attached to the railway car.
As illustrated in
FIGS. 7-9
, the hand brake mechanism is usually either a cast or stamped metal gear housing/back plate assembly usually attached to an outside end wall of the railway car and having a rotatable chain drum therein which can be rotated by turning the hand wheel, typically in a clockwise direction. This rotation is transmitted directly through a drive shaft, a pinion, a gear and a chain drum to wind a brake chain onto the chain drum. The other end of the brake chain normally extends through the bottom of the gear housing and is interconnected with cable or other linkage to the brake rigging (not shown) so as to draw the interconnected brake shoes against the tread surfaces of adjacent railway car wheels and, accordingly, apply the hand brake as intended.
When resistance is offered by the chain to further rotation of the hand wheel, such resistance, acting back through the drum, the gear and pinion, causes a nut to move against a ratchet member which is clamped between respective friction surfaces on the nut and on the drive shaft, thus causing the drive shaft, ratchet and the nut to rotate as a unit. A pawl prevents rotation of the ratchet in the opposite direction.
A gradual release of the brakes may be performed by rotating the hand wheel in an opposite direction, such as in a counterclockwise direction, which partially loosens the nut to reduce the clamping force on the ratchet. This action allows the pinion and gear to rotate to reduce chain load and release the brakes.
Although turning the hand wheel in the opposite direction may operate to release the handbrake in proportion to the extent of such turning, some ratchet member and pawl systems may not permit turning the hand wheel in the opposite direction. Accordingly, most handbrake mechanisms are provided with a quick release, non-spin mechanism which functions to instantly and completely release the handbrake without causing the hand wheel or ratchet member to spin. The quick release mechanism is normally actuated by pivoting a handbrake release handle, the handbrake release handle being attached to a brake release shaft, which, when rotated by the hand brake release handle outside of the gear housing, will disengage the chain drum and lock it in place, thereby permitting the chain to self unwind from the chain drum. Normally, the outer end of the brake release shaft is provided with a tight-fitting lever arm type of handbrake release handle so that to release the handbrake, the handle or lever arm is merely pushed upwardly to rotate the brake release shaft (normally clockwise) as necessary to completely release the handbrake.
Whether the handbrake is released via counterclockwise rotation of the hand wheel or by pushing up the quick release lever, both techniques require an operator to climb on and off each car to manually activate this brake release. This can be a time-consuming, as well as, expensive procedure to perform.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an automatic handbrake release mechanism for a parking brake assembly for a railway vehicle braking system.
It is yet a further object of the invention to provide an automatic, power activated handbrake release mechanism for a parking brake assembly which allows for a quick, inexpensive release of the brakes on each of or a selected number of cars on a railway vehicle. The automatic handbrake release mechanism of the invention eliminates the need for train personnel to climb on and off each of the railway cars to manually release the brakes.
It is yet another object of the invention to design the quick release handle mounting system of the handbrake such that this handle does not rotate upon activation of the automatic handbrake release mechanism of the invention yet allows for a manual activation of the handle in situations where a power source is not available to release the brakes.
It is another object of the invention to design the handbrake such that the quick release handle remains stationary during rotation of the release shaft via the automatic handbrake release mechanism of the invention.
It is yet a further object of the invention to include a means associated with the quick release handle to enable manual release of the handbrake via the quick release handle during situations where a power source is unavailable to actuate the automatic handbrake release mechanism of the invention.
The power activated automatic handbrake release mechanism of the invention comprises a piston assembly engagable with said the railway vehicle handbrake. This piston assembly includes a piston arrangement having a piston rod attached thereto. This piston rod is mounted for movement outward from the piston assembly upon activation of a piston in the piston arrangement. An elongated member having a first end and a second end is provided. The first end of this elongated member is associated with the piston rod at a location remote from said piston assembly such that the elongated member is capable of movement with respect to movement of the piston rod. A release shaft is engageable with the second end of the elongated member such that activation of the piston of the piston assembly causes activation of this release shaft to automatically release the railway vehicle handbrake. The first end of the elongated member is associated with a bottom surface of the piston rod such that this first end can move in a lateral direction upon vertical movement of the piston rod. This lateral movement of the piston rod causes a rotational force to be applied to the release shaft which causes the handbrake to release.
The manually actuated quick release handle assembly for a railway vehicle handbrake having the power actuated handbrake release mechanism of the invention comprises a handle associated with the release shaft which remains stationary during rotational movement of the release shaft upon actuation of the power actuated handbrake release mechanism, a pie shaped opening positioned in the release shaft itself or a circular plate member which is engagable with and capable of rotating the release shaft, and an engaging means engagable with the quick release handle and extending into the pie shaped opening such that a manual movement of the quick release handle to an applied position causes this engaging means to apply a rotational force to the release shaft to cause a manual release of the railway vehicle handbrake.
REFERENCES:
patent: 2940553 (1960-06-01), Newell et al.
patent: 2940554 (1960-06-01), Cameron
patent: 4978178 (1990-12-01), Engle
patent: 5201890 (1993-04-01), Sauer et al.
patent: 5558411 (1996-09-01), Kanjo et al.
James Ray & Associates
Mar Michael
Talavera Melanie
Westinghouse Air Brake Company
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