DE1943792A1 - Inner shoe brake - Google Patents

Description

DR.IN «. F. WUKSTHOFK 8 MÜNCHKN ΘΟ I) IPIlING ₁ (J-PULS 'SCHWEIOERSTRASSE S

DH.K.T.PEC1IMANN DR. ING. U. HKHRENS

PATENT ADVERTISER * I ü 4 J / <J £

1A-36739

Description of the patent application

Girling limited
Birmingham, Warwickshire England

concerning
Inner shoe brake

The invention relates to an inner shoe brake in which two inside the drum on one perpendicular to the Axis of the drum extending support plate arranged brake shoes by a mechanical spreading device in Braking engagement with the drum can be moved apart, with the spreading device from one of the opposite Side of the support plate arranged compression spring can be actuated.

According to the invention it is provided that the compression spring with its line of action is aligned parallel to the support plate and that the device for compressing the spring purpose of contracting the spreader and releasing the Brake from a hydraulic x-piston cylinder device is formed, which can be supplied with a pressure medium in order to overcome the force via spring and the spreader to contract. Preferably that is from the compression spring

009810/1348 " ² "

and the hydraulic KolLen-Zylinuervorrichtung formed Drive with the spreading device via two on the support plate hinged levers connected.

The mechanical spreader and drive unit is generally used as a handbrake or parking brake, while a separate hydraulic actuator is used as a service brake. If necessary, however, the mechanical spreading device and drive unit can also serve as an actuating device for the service brake. "J

"The invention and advantageous details of the invention are in the following with reference to drawings of an embodiment of a mechanical actuator . for an inner shoe brake n-Jier explained.

Fig. 1 shows a partial section through the mechanical Actuation device;

Pig. Figure 2 shows a side view of the in Pig. 1 used Spring drive unit;

Pig. 3 shows an end view of the actuator;

The actuating device shown in the drawings is for use in an inner shoe brake from known construction, which is why here is not described or illustrated in detail. The brake shoes and the hydraulic device for pressing apart these are also not shown. Pig. 1 shows only part of the support plate 1 of the brake, on which a mechanical spreading device 2 is supported, which between each other. Limbs 3 acts, which are parts of the brake shoes or links can act »which transfer pressure to the brake shoes.

009810/1346

The spreader is a simple telescopic arrangement with a massive inner part 6, which with one of the links 3 is engaged, and a tubular outer part 7 with a countersink in one end in which a hardened disc 8 is received, which serves as a stop for the other link 3. In Fig. 1, the telescopic Parts shown in a fully spread position, which corresponds to the conditions when the brake is applied. Two forked levers 9 and 10, which are connected to parts 6 and 7 respectively, have pins 11 on the support plate as pivot points.

The spreading apart and contraction of the spreading device is effected by a spring drive unit 20, the one piston 21, the piston rod 22 on one. cup-shaped part 23 is attached, as well as one with the Piston cooperating cylinder 24 comprises which by means of a .Kolbenbolzens 26 on a cup-shaped arrangement 25 is attached. The adjacent ends of the levers 9, 10 are connected to the corresponding cup-shaped parts 23 and 25, respectively connected, which are pressed apart by a strong helical compression spring 27. This feather thus causes the spreading device to be brought into the spread-apart position shown here. The brake can by supplying a pressure medium to the working space of the cylinder 24 through axial and radial passages 28 in the Piston rod 22 can be released. This pressure medium supply is assigned to one of the handbrake controls of the vehicle and controlled by the same operated valve.

When the engine is running and the handbrake control is in the brake release position, the cylinder is pressurized fed to the piston in the cylinder advanced in

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Position with the spring 27 between the each other opposite cup-shaped! dents pressed together will. Palis the hydraulic supply fails or the engine stops, or if the pressure medium is supplied by a movement the handbrake control is interrupted in the corresponding position of the applied brakes, it enables the acceptance of the hydraulic pressure in the cylinder of the spring 27 to move the parts back into the position shown in order to apply the brake to put on. The actuating device is therefore inherently a safety device, and its arrangement. Is .so compact that there are no installation problems that are otherwise often encountered due to the proximity of parts of the suspension.

Although the actuator is related was described with the handbrake actuation (i.e. as a parking brake), on the other hand it can also be used to actuate the service brake can be used.

Expectations

• 009810/1346

Claims (2)

Claims M.J internal shoe brake, with the two inside the drum brake shoes arranged on a support plate extending perpendicular to the axis of the drum by a mechanical one Spreading device can be moved apart in braking engagement with the drum, with the spreading device from one to the the compression spring arranged on the opposite side of the support plate can be actuated, characterized in that that the compression spring (27) is aligned with its line of action parallel to the support plate (1) and that the Device for compressing the spring for the purpose of contracting the expanding device (2) and releasing the brake from a hydraulic piston-cylinder device (21,24) is formed. 2. Inner shoe brake according to claim 1, characterized in that of the spring (27) and the hydraulic piston-cylinder device (21,24) formed drive with the spreading device (2) via two levers (9,10) is connected, which are articulated (at 11) on the support plate (1). 148 ÜG9810 / 1346 Blank page