Brakes – Position adjusters – Slack
Patent
1995-01-20
1996-09-10
Butler, Douglas C.
Brakes
Position adjusters
Slack
192109F, 192111A, F16C 122, F16D 1375
Patent
active
055536883
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a cutoff valve for pistons of hydraulic self-adjusting devices, in particular for use in hydraulic-self-adjusting devices designed for the permanent, automatic adjustment of the length of control cables.
Hydraulic self-adjusting devices for the permanent, automatic adjustment of the length of control cables are widely known and generally consist of steel cables provided with a protective sheath and attached to an actuating mechanism, such as a pedal for example, with an associated mechanism, such as the clutch of a car for example. These self-adjusting devices carry out adjustment independently of the initial adjustment of the length of the control cable, which is normally carried out when the cable is fitted by means of devices designed for the purpose that operate only during said initial adjustment process.
The Spanish patent P 9002014 describes a hydraulic self-adjusting device which consists basically of a cylindrical main body, joined to the mechanism to be actuated, and an adjustment rod, one of the ends of which, the external end, is attached the control cable, whilst the other end, the internal end, has a piston provided with a cutoff valve, said piston defining two semi-chambers inside the main body between which the hydraulic fluid can flow. Furthermore, said device comprises an adjustment spring and volumetric compensation means. This devices operates in such a way that the required increase in length of the control cable as a result of the mechanical demands placed on the mechanism it actuates (for example the progressive wear of the facing on the clutch plate of a car) is provided by the increase in length of the portion of the adjustment rod which protrudes from the main body of the self-adjusting device.
One of the cutoff valves for such hydraulic self-adjusting devices which is described by said patent P 9002014 comprises a through element, a cutoff element and an opening spring which works in compression, these elements being arranged coaxially with the adjustment rod. The purpose of the opening spring is to maintain the cutoff valve open so that the liquid fluid can flow between the two semi-chambers of the main body when the adjustment rod is not being pulled by the control cable. The cutoff valve establishes the hydraulic communication between the two semi-chambers by means of the close fit between the cutoff element of the valve and the inner wall of the main body.
This cutoff valve described by the Spanish patent P 9002014 suffers from the drawback that it consists of a large number of components, which increases the cost of production of the valve as well as its assembly.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a new type of cutoff valve which avoids the disadvantages of the prior art, in particular a relatively large number of components of the known types of cutoff valves.
It is another object of the present invention to provide a cutoff valve which has a new structure and high operational reliability.
The cutoff valve according to the invention constitutes the body of the piston of a hydraulic self-adjusting device such as those described above, i.e. a hydraulic self-adjusting device which comprises the following known elements: a main body which is cylindrical, elongated and hollow and which contains a liquid fluid; an adjustment rod, one of the ends of which, the internal end, is fitted with said piston whilst the other end, the external end, protrudes from the main body by a variable amount and is attached to the corresponding end of the control cable; an adjustment spring arranged inside the main body coaxially with the rod, said spring working constantly in compression, one of its ends resting against the end of the main body from which the rod protrudes, its other end resting against the internal end of the rod by means of a transverse support shoulder joined to said rod, such that the spring tends to constantly push the rod towards the interior of the main bod
REFERENCES:
patent: 2593192 (1952-04-01), Rockwell
patent: 4735298 (1988-04-01), Hauguel
patent: 5211379 (1993-05-01), Porter
patent: 5265710 (1993-11-01), Gabas et al.
LandOfFree
Cutoff valve for pistons of hydraulic self-adjusting devices does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cutoff valve for pistons of hydraulic self-adjusting devices, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cutoff valve for pistons of hydraulic self-adjusting devices will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1313693