PISTON COVER.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Applications
- Current Assignee / Owner
- DIVISION TECHNIQUE SERVICE BREVETS BENDIX EUROPE
- Filing Date
- 1990-01-18
- Publication Date
- 1991-07-19
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Existing piston caps can create sealed chambers due to contact with the brake wall, leading to unequal air pressure distribution and incorrect brake operation.
The piston cap is designed with notches or lugs on the fold to prevent sealing between chambers, allowing air circulation and equalizing pressure.
Ensures equal air pressure distribution across chambers, ensuring proper brake operation by preventing sealed chamber formation.
Abstract
Description
PISTON CAP The present invention constitutes an addition to French patent application 88 17297 filed on 28.12.88 in the name of the applicant. The cap described in the main patent application is entirely satisfactory. However, it has a fold that could come into contact with a wall of the brake thus equipped. This contact then creates two chambers that are substantially sealed from each other. The vent intended to allow air to escape from the closed volume then only acts on one of the two chambers. When two vents are provided, the air escape is not identical in both chambers. In all cases, therefore, this results in a difference between the pressures in the two chambers, a difference that is detrimental to the proper functioning of the brake. The present invention aims to overcome this drawback. According to the invention, the outer part of the fold is provided with a means preventing sealing of the contact. This means may consist either of a plurality of notches made in the fold, or of a plurality of lugs projecting from the fold. The invention and its other objects, advantages, and features will become clearer upon reading the following description of preferred embodiments, given by way of non-limiting example, and to which a drawing is attached, on which The single figure represents in schematic cross-section a cap according to the invention. With reference to this Figure, on which the numerical references have been taken from the main patent application, the person skilled in the art can easily recognize the metal insert 36 with the tongue 42 and the notches 44, the bead 32 fitting into an annular groove 34 made on the head of the piston 24. The body of the cylinder 26 has a wall that may be in contact with the fold 55 shown on the cap. To prevent the volume enclosed by the cap, piston 24, and cylinder 26 from being divided into two chambers sealed against each other, a means 50 is provided to prevent any sealing between the two chambers at the point of contact between the fold 55 and the wall of cylinder 26. This means 50 may consist of notches formed on the outer part of the fold. It may also consist of lugs projecting from the fold at the point of contact. Such a method therefore allows air to circulate from one chamber to the other, thus avoiding any pressure difference between the two chambers. Obviously, a person skilled in the art will be able to make many modifications to the cap according to the invention without going out of the scope of the invention as defined by the attached claims.
Claims
DEMANDS 1. Piston cap according to any one of the claims of the main patent application, the intermediate part of which between said retaining part and said bead (32) has a fold capable of coming into contact with a wall, characterized in that the outer part of the fold is provided with a means (50) preventing the sealing of said contact.
2. Piston cap according to claim 1, characterized in that said means consists of a plurality of notches made in the fold.
3. Piston cap according to claim I, characterized in that said means consists of a plurality of lugs projecting from the fold.