Pumps – Three or more cylinders arranged in parallel – radial – or... – Radial cylinders
Patent
1995-02-07
1997-07-15
Thorpe, Timothy
Pumps
Three or more cylinders arranged in parallel, radial, or...
Radial cylinders
91496, F04B 104
Patent
active
056477295
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a radial piston pump of the type, in which an eccentric rotor is adapted to cause the pistons to perform a reciprocating movement within radial cylinders in a pump body.
2. Discussion of the Prior Art
Radial piston pumps of the type in which the cylinders are connected via a lateral suction opening to a liquid reservoir and have their radial outer ends each connected to a circumferentially located pressure passage through a connecting opening that accommodates a pressure valve. The pressure valves are pressed on seats within the respective connecting openings by means of at least one common resilient ring member that is located within the circumferential passage under tangential pretension. An annular wall portion surrounds the pump body to overlie and cover the circumferential pressure passage in the valve body. Such a pump is disclosed in German Offenlegungsschrift 1.453.663.
With this well-known pump the annular wall portion surrounding the pump body is intended to close the circumferential pressure passage at the outer circumference thereof. The tightness of the circumferential passage as a pressure passage is completely determined by sealing rings provided in circumferential grooves on either side of the circumferential pressure passage.
SUMMARY OF THE INVENTION
The invention aims at providing an improved pump of the above type, which is suitable for higher pump pressures (up to 1000 bar) and which is of a compact and light-weight construction, which is of particular importance for use in hydraulically operated tools.
In accordance with the invention this aim is achieved in that the circumferential pressure passage is outwardly sealed by an annular member of plastic material and of a substantially trapezoid-shaped cross-section. The longer parallel side of the cross-section faces radially inwardly and includes a circumferential groove for receiving the resilient ring member. The annular member is adapted to be inserted radially inwardly into the circumferential pressure passage.
To enable the annular member of plastic material to be placed into the circumferential pressure passage in a radial inward direction, the annular member will, at first, have to be expanded and placed in position on the circumferential outer surface of the pump body from an end of the latter, after which the annular member is permitted to contract to its original (untensioned) diameter and width and thereby engage into the circumferential pressure passage. Due to the trapezoid-shaped cross-section of the annular member of plastic material the latter will tend to slightly bulge convexly outwardly beyond the circumferential outer surface of the pump body. The annular wall portion, however, will cause the annular member of plastic material to return to a flat shape (as seen in the axial direction), due to which the annular member will be pressed with its inwardly facing base of the trapezoid firmly against the sidewalls of the circumferential passage. In operation, the pressure of the annular member of plastic material against the sidewalls of the circumferential pressure passage will be further increased by the pressure prevailing within the inner circumferential groove of the annular member, which pressure tends to bend the lateral wall portions on either side of the groove axially outwardly.
In accordance with a further feature of the invention the bottom of the circumferential passage is, at a location between two adjacent cylinders, connected to a passage that extends radially inwardly and is, in turn, connected to an axial passage that leads to a pressure connection.
The invention will be hereinafter further described by way of example with reference to the accompanying drawing.
SUMMARY OF THE INVENTION
FIG. 1 shows a axial cross-sectional view through a radial piston pump according to the invention, as seen along the line I--I in FIG. 2;
FIG. 2 represents a cross-section along the line II--II in FIG. 1;
FIG. 3 is an enlarged longitudinal c
REFERENCES:
patent: 4977606 (1990-12-01), Budecker
patent: 5382140 (1995-01-01), Eisenbacher
patent: 5509347 (1996-04-01), de Jong et al.
de Jong Leendert Willem C.
Masseling Willem Herman
van Heiningen Arjan Peter
Applied Power Inc.
Korytnyk Peter G.
Thorpe Timothy
LandOfFree
Radial piston pump does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Radial piston pump, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Radial piston pump will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1488293