Power plants – Pressure fluid source and motor – Pulsator
Patent
1996-08-16
1998-03-31
Lopez, F. Daniel
Power plants
Pressure fluid source and motor
Pulsator
B60T 1120
Patent
active
057325570
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a hydraulic tandem master cylinder comprising: a body formed with a bore which is at least partially cylindrical and of which one end forms an opening and a second end is dosed by a bottom formed by a detachable part, this bore comprising two fluid feed ducts spaced apart one from the other by a defined distance; a primary piston and a secondary piston arranged to slide in the bore, the primary piston being connected to an actuating rod which passes through the opening, and the primary piston and the secondary piston presenting together a defined effective overall size; a primary pressure chamber defined in the bore between the primary and secondary pistons, this chamber containing at least a first spring which is confined in a space of defined maximal length and which exerts between the pistons a first spring force which urges them apart from each other; a secondary pressure chamber defined in the bore between the secondary piston and the bottom, this chamber containing at least a second spring which exerts between the secondary piston and the bottom a second spring force in a direction which urges this secondary piston away from the bottom; first and second sealing elements, co-operating respectively with the primary and secondary pistons, to ensure sealing of the primary and secondary pressure chambers respectively; at least one guide means for the actuating rod, provided adjacent the opening; and adjustment means accessible from the vicinity of the second end of the body, to enable adjustment one relative to the other of the defined distance and the defined effective overall size.
BACKGROUND OF THE INVENTION
A master cylinder of this type is described for example in the document FR-A-2 312 399.
One of the difficulties which have to be overcome in the manufacture of tandem master cylinders is to succeed in reducing both their cost and their overall size, a man skilled in the art finding these two requirements somewhat mutually contradictory to the extent that currently known solutions for ensuring a reduction in overall length oblige the tandem master cylinder to be made of a large number of parts, especially in view of its adjustment, and therefore at a higher cost.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a tandem master cylinder in which both the overall size and the cost of manufacture, particularly the cost of adjustment, are simultaneously reduced.
To this end, the tandem master cylinder of the invention is essentially characterised in that the first spring is retained within a cage which constitutes the space of defined maximal length, in that the cage comprises a rigid cup of which a peripheral part presents a purchase for the first spring in the vicinity of the primary piston and of which a central part is retained by a stop, in that the stop is solid with a first end of a spacer which passes slidingly through the cup and of which a second end screwed in the secondary piston, and in that the adjustment means are accessible from the secondary pressure chamber and cooperate with the spacer to enable an adjustment of the defined maximal length of the cage by relative displacement of the spacer and of the secondary piston.
Moreover, according to a preferred embodiment of the invention, the bore presents a diameter which reduces stepwise from the bottom of this bore until the opening, the first seal is borne by the primary piston, the second seal is accommodated in the bore, and the opening of the bore takes the form of a shoulder, which itself constitutes the guide means for the actuating rod.
The overall size of the master cylinder of the invention may be further reduced by arranging that a first one of the two fluid feed ducts opens into the bore between the shoulder of the bore and the primary pressure chamber, and that the primary piston has a non return valve passing through it which enables flow from the first fluid feed duct into the primary pressure chamber.
The adjustment means comprises, for example, a screw thread f
REFERENCES:
patent: 3147596 (1964-09-01), Wallace
patent: 3355887 (1967-12-01), Balster
patent: 3357183 (1967-12-01), Krieger
patent: 3393514 (1968-07-01), Cripe
patent: 4685301 (1987-08-01), Bacardit et al.
patent: 5036664 (1991-08-01), Camm
patent: 5044161 (1991-09-01), Schiel et al.
patent: 5161376 (1992-11-01), Hartmann
patent: 5191765 (1993-03-01), Ruehl
Lopez F. Daniel
McCormick Jr. Leo H.
LandOfFree
Master cylinder with simplified adjustment does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Master cylinder with simplified adjustment, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Master cylinder with simplified adjustment will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-43106