US3880472A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulic braking system for a trailer
Assignee: Bendix Corp
•
Filing: 1973-11-19
•
Granted: 1975-04-29
•
Expires: 1993-11-19
Abstract
Abstract A tow vehicle-trailer braking system where a transducer in the brake line of the tow vehicle and a transducer in the brake line of the trailer are evaluated by a comparator to develop an operational signal to operate the wheel brakes of the trailer. The operational signal positions a solenoid valve to regulate the communication of fluid under pressure to the wheel brakes of the trailer. The fluid under pressure is developed by a pump. The pump is driven by a cam attached to the wheel of the trailer until the predetermined pressure level for the fluid is reached. Upon reaching this predetermined pressure, the pressurizing piston in the pump becomes disengaged from the cam.
Inventors
- 👤 Richard L Lewis
- 👤 Robert K Wilson
- 👤 George B Hickner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:06
CPC Classifications
B; B60; B60T; B60T13/00; B60T13/10; B60T13/12; B60T13/14; B60T13/141; B60T13/66; B60T13/662
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
195 words
In a tow vehicle-trailer braking system having a valve means for regulating the actuation of the wheel brakes in the trailer in response to an input signal derived by comparing the braking force supplied the wheel brake of the tow vehicle with the braking force suPplied the wheel brakes in the trailer, pumping means located in the trailer for maintaining the available braking force therein above a predetermined level, said pumping means comprising: a housing having a first bore therein, said first bore having an entrance port and an exit port, said entrance port being connected to a reservoir filled with a fluid, said exit port being connected to a storage container; piston means located in the first bore; cam means connected to a wheel on the trailer for reciprocating the piston means in said bore upon rotation of said wheel, said piston means upon reciprocating pressurizing the fluid received in said bore through the entrance port before being communicated through the exit port into the storage container to establish said available braking force; and control means responsive to the pressurized fluid in said storage container for disengaging the piston means and the cam means.
Claim 2
Dependent Claim
195 words
In a tow vehicle-trailer braking system having a valve means for regulating the actuation of the wheel brakes in the trailer in response to an input signal derived by comparing the braking force supplied the wheel brake of the tow vehicle with the braking force suPplied the wheel brakes in the trailer, pumping means located in the trailer for maintaining the available braking force therein above a predetermined level, said pumping means comprising: a housing having a first bore therein, said first bore having an entrance port and an exit port, said entrance port being connected to a reservoir filled with a fluid, said exit port being connected to a storage container; piston means located in the first bore; cam means connected to a wheel on the trailer for reciprocating the piston means in said bore upon rotation of said wheel, said piston means upon reciprocating pressurizing the fluid received in said bore through the entrance port before being communicated through the exit port into the storage container to establish said available braking force; and control means responsive to the pressurized fluid in said storage container for disengaging the piston means and the cam means.
Claim 3
Dependent Claim
59 words
The tow vehicle-trailer braking system, as recited in claim 1, wherein said piston means includes: plunger means having a face which opens and closes the entrance port when a head thereon contacts said cam means to produce said reciprocal movement; and spring means connected to said housing for urging the head of the plunger means toward the cam means.
Claim 4
Dependent Claim
40 words
The tow vehicle-trailer braking system, as recited in claim 2, wherein said piston means further includes: check valve means located in said first bore for preventing fluid under pressure from being communicated from the exit port to the entrance port.
Claim 5
Dependent Claim
40 words
The tow vehicle-trailer braking system, as recited in claim 2, wherein said control means includes: lever means located in said housing for holding said plunger means away from the cam means when said predetermined level of braking force is achieved.
Claim 6
Dependent Claim
112 words
The tow vehicle-trailer braking system, as recited in claim 4, wherein said control means further includes: second piston means located in a second bore in the housing, said second bore being connected to said first bore by a passage located between said check valve means and said exit port, said passage communicating the pressurized fluid created in the first bore to the second piston means, said lever means being attached to said second piston means, said second piston means reacting to said fluid under pressure to move in said second bore and hold said lever means in contact with said first piston means to prevent the head from contacting said cam means.
Claim 7
Dependent Claim
105 words
The tow vehicle-trailer braking system, as recited in claim 5, wherein said second piston means further includes: a shaft having a first end located in said second bore; first sealing means located on the first end of said shaft to form a first chamber with the second bore; and second sealing means located on said shaft between the first sealing means and a second end where the lever means is attached, said first and second sealing means and said second bore forming a second chamber, said second chamber being connected to said passage, said fluid under pressure in the second chamber acting on the shaft.
Claim 8
Dependent Claim
34 words
The tow vehicle-trailer braking system, as recited in claim 6, wherein said control means further includes: spring means connected to said first end of the shaft for opposing movement by said fluid under pressure.
Claim 9
Dependent Claim
85 words
The tow vehicle-trailer braking system, as recited in claim 6, wherein said control means further includes: shuttle valve means having a first closure means separated from a second closure means, said first closure means being connected to said passage to receive said fluid under pressure, said second closure means being connected to said first chamber and said reservoir; and resilient means located in said housing for urging said second closure means shut in opposition to the fluid under pressure acting on the first closure means.
Claim 10
Dependent Claim
48 words
The tow vehicle-trailer braking system, as recited in claim 8, wherein said shuttle valve includes: a cylinDrical body having a first stem and a second stem, said first stem extending beyond a first seat of the housing, said second stem extending beyond a second seat of the housing.
Claim 11
Dependent Claim
80 words
The tow vehicle-trailer braking system, as recited in claim 9, wherein said first closure means includes: first ball means located adjacent the first seat; and first spring means for urging said first ball means toward said first seat and against the first stem to allow the fluid under pressure to flow into the first chamber to act on the first end of the shaft of the second piston means to prevent the lever means from contacting the first piston means.
Claim 12
Dependent Claim
174 words
The tow vehicle-trailer braking system, as recited in claim 10, wherein said second closure means includes: second ball means located adjacent said second seat; and second spring means for urging said second ball means toward said second seat and against the second stem, said second spring means having a greater compressive force than said first spring means, said second spring means holding said second ball on the second seat until the fluid pressure acting on the first ball means can overcome the second spring means, said second spring upon collapsing allowing the first spring means to hold the first ball means against the first seat to prevent the fluid under pressure from being communicated to the first chamber, said fluid under pressure in the first chamber upon the second ball means moving away from the second seat being vented to the reservoir to allow the fluid under pressure in the second chamber to move the shaft and lever means into engagement with the first piston means to prevent further reciprocation by said cam means.
Claim 13
Dependent Claim
142 words
The tow vehicle-trailer braking system, as recited in claim 11, wherein said valve means for regulating the wheel brakes in the trailer includes: a housing having a bore therein, said bore having a first port connected to said storage chamber containing the fluid under pressure, a second port connected to said wheel brakes in the trailer, and a third port connected to said reservoir; and poppet valve means responsive to said input signal for permitting fluid under pressure to flow through the first port and into the second port in a first mode of operation for terminating the flow through the first port while maintaining the fluid under pressure at the second port in a second mode, and allowing the fluid under pressure at the second port to flow through the third port to the reservoir in a third mode of operation.
Claim 14
Dependent Claim
39 words
The tow vehicle-trailer braking system, as recited in claim 12, wherein said poppet valve means includes: solenoid means responsive to the input signal for positioning the poppet valve means to develop said first, second, and third modes of operation.
Claim 15
Dependent Claim
123 words
The tow vehicle-trailer braking system, as recited in claim 13, wherein said input signal is derived from means comprising: first pressure transducer means located in the trailer and connected to receive the fluid flow from the second port of the housing of the regulating valve means and generate a trailer braking signal; second pressure transducer means located in the tow vehicle and connected to receive fluid under pressure supplied to operate the wheel brakes of the tow vehicle for generating a tow vehicle braking signal; comparator means for receiving and evaluating said trailer braking signal with the tow vehicle braking signal to develop said input signal; and switching means connected to said comparator means for transmitting said input signal to the solenoid means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-28 | 1978-10-28 | 1979-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-28 | 1982-10-28 | 1983-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-28 | 1986-10-28 | 1987-04-29 | $7700.00 | Window Closed / Lapsed |