US3682049A - Hydraulic vehicle brakes - Google Patents

Hydraulic vehicle brakes Download PDF

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Publication number
US3682049A
US3682049A US1753A US3682049DA US3682049A US 3682049 A US3682049 A US 3682049A US 1753 A US1753 A US 1753A US 3682049D A US3682049D A US 3682049DA US 3682049 A US3682049 A US 3682049A
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United States
Prior art keywords
piston
cylinder
piston members
separate
slave cylinder
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US1753A
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English (en)
Inventor
David William Gee
Michael Albert Carey
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Individual
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Individual
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D65/00—Parts or details
    • F16D65/14—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position
    • F16D65/16—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position arranged in or on the brake
    • F16D65/22—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position arranged in or on the brake adapted for pressing members apart, e.g. for drum brakes

Definitions

  • the piston means is constructed as two separate piston members, axially movable relative to each other and normally urged apart by spring means,
  • Interengag'ing spigot and socket means on the piston members may be provided to guide the two members and stabilize them against tipping movement.
  • Dual slave cylinders are known in which an intermediate, floating piston is positioned in the cylinder between opposed actuating pistons to divide the cylinder space into two separate working chambers, one adjacent each piston and connected to separate pressure supplies.
  • the intermediate piston serves to equalize the forces applied by the actuating pistons, ir-
  • the intermediate piston may remain stationary for very long periods, and is liable to become corroded to the cylinder wall or for its seals to become weakened and, in some cases, locally adhered to the cylinder wall.
  • a dual slave cylinder for hydraulic wheel brake comprising a cylinder body housing a pair of opposed actuating pistons at opposite ends of the cylinder, a pair of intermediate floating pistons dividing the cylinder space into two separate working chambers, one adjacent each actuating piston, the intermediate pistons being axially movable relative to each other, and resilient means acting between the two intermediate pistons and tending to urge them apart.
  • the intermediate pistons are normally spaced apartby the resilient means, but are pressed against each other when the slave cylinder is pressurized, so as to provide some exercise of the intermediate piston seals, even when both working chambers are substantially equally pressurized (which will usually be the case during service brake operation). Without such exercise, the seals could eventually stick to the cylinder wall.
  • the space between the two intermediate pistons, which is passive, is vented to atmosphere and the effective areas of the intermediate pistons are equal to the full cylinder area, to ensure maximum pressure differential, acting on each of the two pistons during hydraulic brake actuation.
  • FIGS. 1 and 2 are axial sections of the respective slave cylinders.
  • the slave cylinder shown in FIG. 1 comprises a housing or cylinder body 10 having pressure inlets 11, 12
  • the intermediate pistons 18, 19 divide the cylinder space into two separate working chambers 26, 27, one adjacent each piston 13, 14 and served by the respective inlets ll, 12.
  • the passive space 28 between the intermediate pistons is vented to atmosphere by a vent hole 29 open at all'times to atmosphere so as to prevent the buildup of pressure in the passive space.
  • the slave cylinder is shown in its normal, unpressurized condition.
  • both chambers 26 and 27 are supplied with fluid under pressure, which presses the pistons 18, 19 together, exercising the seals 20, 21, and forces the pistons 13, 14 outwardly to apply the brake shoes (not shown) engaged by tappets l6, 17.
  • the brakes are applied by the pressure in the other system, the pistons 18, 19 moving as'one to abut and force outwardly one piston 13 or 14.
  • the spring washer 24 is of sufl'icient rigidity and suitable size to ensure that excessive pedal travel is not required to compress it as a prerequisite to brake application.
  • the slave cylinder shown in FIG. 2 is of generally similar construction and corresponding parts in FIGS. 1 and 2 are identified by like reference numerals.
  • the pistons 18, 19 are of greater axial length, and the spigot and socket connection 22, 23 is omitted.
  • This slave cylinder is designed for use in an internal shoe drum brake in which adjustment to compensate -for friction pad wear is effected at the center and one end of each shoe, so that one of the shoe-ends actuated by the cylinder is moved progressively outwardly, away from the cylinder, as adjustment is effected.
  • the resilient means in this embodiment takes the form of a coil compression spring 30 of sufficient length to keep the intermediate pistons 18, 19 in contact with the respective actuating pistons l3, 14 throughout the range of available wear compensating adjustment.
  • the left hand actuating piston 13 and intermediate piston 18 define between them a working chamber 26 of extended axial length, so that the piston 18 has sufficient movement to cater for adjustment and actuation before the piston seal 20 closes off the pressure inlet 11. Travel of the pistons 14 and 19 is limited by positive stop means, such as a circlip (split ring) 31. Operation of this slave cylinder is as described in relation to the cylinder of FIG. 1. I
  • the effective area over which the two intermediate pistons are'exposed to atmospheric pressure is the full area of the cylinder.
  • the spigot 22- does not make a gas tight fit in socket 23, and in FIG. 2 it is apparent that the space 28 is bounded on one side by the full face of piston 19.
  • the pistons are each subjected in use to the full difierence in pressure between the hydraulic pressure on one face and atmospheric pressure on the other, and this pressure difference acts over the full areas of the pistons.
  • a dual slave cylinder for an hydraulic wheel brake of the type which is connected to separate pressure supplies and includes a cylinder body having a cylinder space, a pair of opposed actuating pistons at 3 opposite ends of said cylinder space, intermediate, floating piston means in said cylinder space between said actuatingpistons to define therewith a pair of working chambers, oneadjacent each said actuating pistons, the improvement which comprises a pair of separate and individually sealed piston members constituting said floating piston means, said piston members being adapted for axial movement towards and away from each other and defining a passive cylinder space therebetween, vent means open at all times to atmosphere leading to said passive space for preventing the buildup of pressure therein, separate inlets to said working chambers including means for connecting said inlets to said separate pressure supplies, and spring means acting between said piston members to urge the same apart, said piston members being constructed and arranged to move slightly towards each other in opposition to said spring means upon delivery of pressure to the working chambers from said separate supplies so as to exercise the seals of said piston members and prevent said

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Braking Arrangements (AREA)
US1753A 1969-01-20 1970-01-09 Hydraulic vehicle brakes Expired - Lifetime US3682049A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB322369 1969-01-20

Publications (1)

Publication Number Publication Date
US3682049A true US3682049A (en) 1972-08-08

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ID=9754293

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Application Number Title Priority Date Filing Date
US1753A Expired - Lifetime US3682049A (en) 1969-01-20 1970-01-09 Hydraulic vehicle brakes

Country Status (4)

Country Link
US (1) US3682049A (enrdf_load_stackoverflow)
DE (1) DE2002418C3 (enrdf_load_stackoverflow)
ES (1) ES375680A1 (enrdf_load_stackoverflow)
GB (1) GB1264626A (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3002715A1 (de) * 1980-01-25 1981-07-30 Herion-Werke Kg, 7012 Fellbach Dichtungsanordnung

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3039295C2 (de) * 1980-10-17 1983-07-28 Deutsche Perrot-Bremse Gmbh, 6800 Mannheim Radzylinder für eine hydraulisch betätigbare Trommelbremse eines Kraftfahrzeuges

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR779383A (fr) * 1933-12-29 1935-04-03 Système de freinage hydraulique pour véhicules
US2104735A (en) * 1932-05-18 1938-01-11 Bendix Aviat Corp Brake
US2313431A (en) * 1940-04-08 1943-03-09 Bendix Aviat Corp Brake
GB646824A (en) * 1942-05-01 1950-11-29 Fiat Spa Improvements relating to fluid pressure transmission systems
US3358448A (en) * 1966-06-27 1967-12-19 Midland Ross Corp Brake motor
US3477549A (en) * 1968-06-04 1969-11-11 Ford Motor Co Dual automotive brake system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2104735A (en) * 1932-05-18 1938-01-11 Bendix Aviat Corp Brake
FR779383A (fr) * 1933-12-29 1935-04-03 Système de freinage hydraulique pour véhicules
US2313431A (en) * 1940-04-08 1943-03-09 Bendix Aviat Corp Brake
GB646824A (en) * 1942-05-01 1950-11-29 Fiat Spa Improvements relating to fluid pressure transmission systems
US3358448A (en) * 1966-06-27 1967-12-19 Midland Ross Corp Brake motor
US3477549A (en) * 1968-06-04 1969-11-11 Ford Motor Co Dual automotive brake system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3002715A1 (de) * 1980-01-25 1981-07-30 Herion-Werke Kg, 7012 Fellbach Dichtungsanordnung

Also Published As

Publication number Publication date
DE2002418A1 (de) 1970-07-23
ES375680A1 (es) 1972-05-16
DE2002418C3 (de) 1975-12-04
GB1264626A (enrdf_load_stackoverflow) 1972-02-23
DE2002418B2 (de) 1975-04-24

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