GB2141485A

GB2141485A - Hydraulic piston/cylinder

Info

Publication number: GB2141485A
Application number: GB08415240A
Authority: GB
Inventors: Heinz Aldinger
Original assignee: WEBER OELHYDRAULIK
Current assignee: WEBER OELHYDRAULIK
Priority date: 1983-06-14
Filing date: 1984-06-14
Publication date: 1984-12-19
Also published as: DE3321486A1; GB8415240D0; IT1179199B; IT8448376A0

Abstract

The hydraulic piston/cylinder assembly (5) has a cylinder (6) and a piston (8) which is inserted from one end for which an end step is provided, in the assembled condition of the cylinder. The piston (8) is provided at that end which is inserted first (13) with at least one radially projecting nose (14) arranged on the circumference of the piston. The cylinder (6) at that end which receives the piston has a first section (16) with a diameter corresponding to that of the piston, with grooves (17) matched to the shape, extent and number of noses (14) on the piston (8) so that these are easily inserted in the housing. After insertion, the piston is secured against falling out by turning it, once the noses (14) pass into a section (15) of larger diameter, so that the noses lie behind the shoulder formed between the first and second sections. <IMAGE>

Description

SPECIFICATION Hydraulic piston/cylinder The invention concerns a hydraulic piston/cylinder assembly.

Such a, preferably single-acting, hydraulic cylinder requires an end stop for the piston, which prevents the piston being moved too far out of the cylinder when the cylinder space is pressurised. This is set into the cylinder, which is open at one side, upon assembly. For this, a separate end stop must be introduced, for example by the use of a screw connection.

The invention aims to deal with this problem, and to provide a hydraulic piston/cylinder assembly which has fewer constructional parts and is easier to assemble.

Accordingly, the invention proposes a hy- draulic piston/cylinder assembly having a cylinder with a first section of which the diameter is the same as that of the piston, and a second section at the closed end of the cylinder which is of larger diameter, wherein the piston has at least one radial projection near its head and said first section of the cylinder has a longitudinal groove along which the projection may pass until it enters said second section, turning of the piston bringing the projection behind a shoulder between the first and second sections to prevent the piston being ejected by pressure fluid. Due to the formation of the open end of the cylinder and of the end of the piston which is to be inserted, this can be put in position in the cylinder in a simple manner and secured after insertion by turning.Thereafter, the projection on the piston comes to lie by the shoulder.

According to the invention, there is thus the advantage that, by contrast with the prior art, the hydraulic piston/cylinder assembly consists of two parts which are easy to manufacture, and which can be quickly and easily assembled.

Suitable constructions and further developments of the invention will be appreciated from the following description of a preferred embodiment of the invention.

In the drawings: Figure 1 shows a hydraulic cylinder, in a partially broken away, schematic half-section; Figure 2 shows a section on Il-Il in Fig. 1; and Figure 3 shows a section on Ill-Ill in Fig.

1.

A hydraulic cylinder, generally referenced 5, has a cylinder 6 with a connection 7 for the hydraulic fluid, and a piston 8 of predetermined diameter 9. Both the cylinder 6 and the piston 8 have eyes 10 for receiving bolts, the axes of which, perpendicular to the plane of the drawing, lie perpendicular to the piston movement 11. The axes of both eyes are, when installed parallel to one another and are held in this position by virtue of their attachment to external means.

At the end 1 2 open in one direction of the cylinder 6, there are seals, known per se, for the piston 8.

The piston, at that end 1 3 which is inserted first into the cylinder on assembly, is provided with two radial projections or noses 14.

As can be seen from Fig. 3. the two noses 14 lie diametrally opposite one another and perpendicular to the axis of the eye 10. The piston 8 is guided on the inside 1 5 of the cylinder 6 by means of the noses 14.

The cylinder 6 has over a first section 1 6 near the open end 12, a similar diameter to the diameter 9 of the piston 8. Over the remainder of its length (a second section), the cylinder has a larger diameter (corresponding to that of the noses 14), thus forming a shoulder 1 9 between the two sections. In order to allow insertion of the noses 14, there are longitudinal grooves 1 7 along said first section 1 6 which correspond in shape and size with the noses 14. These grooves 1 7 also lie diametrically opposite one another (Fig. 2), and on the same diametral axis as the axis of the eye 10 on the cylinder.Thus after the piston has been slid on from left to right, the piston must be turned through 90 to bring the axes of the eyes 10 parallel.

In this position, excessive longitudinal movement of the piston 8 towards the left is prevented by abutment of the noses 14 against the shoulder 1 9. It is important, however, that the piston is not allowed after installation to turn through 90 to again bring the noses 14 and the grooves 1 7 into alignment.

Naturally, the sealing means for the piston must also seal the grooves 1 7.

Any number of noses 14 and corresponding grooves 1 7 may be provided, provided the amount of turning required to bring the axes of the eyes parallel leaves the noses 1 7 behind the shoulder 1 9. This is the amount 360 divided by 2n, where n is the number of noses.

1. A hydraulic piston/cylinder assembly having a cylinder with a first section of which the diameter is the same as that of the piston, and a second section at the closed end of the cylinder which is of larger diameter, wherein the piston has at least one radial projection near its head and said first section of the cylinder has a longitudinal groove along which the projection may pass until it enters said second section, turning of the piston bringing the projection behind a shoulder between the first and second sections to prevent the piston being ejected by pressure fluid.

2. A hydraulic piston/cylinder assembly as claimed in claim 1 wherein the piston and cylinder at their free ends each have a transverse eye for receiving fixing means.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Hydraulic piston/cylinder The invention concerns a hydraulic piston/cylinder assembly. Such a, preferably single-acting, hydraulic cylinder requires an end stop for the piston, which prevents the piston being moved too far out of the cylinder when the cylinder space is pressurised. This is set into the cylinder, which is open at one side, upon assembly. For this, a separate end stop must be introduced, for example by the use of a screw connection. The invention aims to deal with this problem, and to provide a hydraulic piston/cylinder assembly which has fewer constructional parts and is easier to assemble. Accordingly, the invention proposes a hy- draulic piston/cylinder assembly having a cylinder with a first section of which the diameter is the same as that of the piston, and a second section at the closed end of the cylinder which is of larger diameter, wherein the piston has at least one radial projection near its head and said first section of the cylinder has a longitudinal groove along which the projection may pass until it enters said second section, turning of the piston bringing the projection behind a shoulder between the first and second sections to prevent the piston being ejected by pressure fluid. Due to the formation of the open end of the cylinder and of the end of the piston which is to be inserted, this can be put in position in the cylinder in a simple manner and secured after insertion by turning.Thereafter, the projection on the piston comes to lie by the shoulder. According to the invention, there is thus the advantage that, by contrast with the prior art, the hydraulic piston/cylinder assembly consists of two parts which are easy to manufacture, and which can be quickly and easily assembled. Suitable constructions and further developments of the invention will be appreciated from the following description of a preferred embodiment of the invention. In the drawings: Figure 1 shows a hydraulic cylinder, in a partially broken away, schematic half-section; Figure 2 shows a section on Il-Il in Fig. 1; and Figure 3 shows a section on Ill-Ill in Fig. 1. A hydraulic cylinder, generally referenced 5, has a cylinder 6 with a connection 7 for the hydraulic fluid, and a piston 8 of predetermined diameter 9. Both the cylinder 6 and the piston 8 have eyes 10 for receiving bolts, the axes of which, perpendicular to the plane of the drawing, lie perpendicular to the piston movement 11. The axes of both eyes are, when installed parallel to one another and are held in this position by virtue of their attachment to external means. At the end 1 2 open in one direction of the cylinder 6, there are seals, known per se, for the piston 8. The piston, at that end 1 3 which is inserted first into the cylinder on assembly, is provided with two radial projections or noses 14. As can be seen from Fig. 3. the two noses 14 lie diametrally opposite one another and perpendicular to the axis of the eye 10. The piston 8 is guided on the inside 1 5 of the cylinder 6 by means of the noses 14. The cylinder 6 has over a first section 1 6 near the open end 12, a similar diameter to the diameter 9 of the piston 8. Over the remainder of its length (a second section), the cylinder has a larger diameter (corresponding to that of the noses 14), thus forming a shoulder 1 9 between the two sections. In order to allow insertion of the noses 14, there are longitudinal grooves 1 7 along said first section 1 6 which correspond in shape and size with the noses 14. These grooves 1 7 also lie diametrically opposite one another (Fig. 2), and on the same diametral axis as the axis of the eye 10 on the cylinder.Thus after the piston has been slid on from left to right, the piston must be turned through 90 to bring the axes of the eyes 10 parallel. In this position, excessive longitudinal movement of the piston 8 towards the left is prevented by abutment of the noses 14 against the shoulder 1 9. It is important, however, that the piston is not allowed after installation to turn through 90 to again bring the noses 14 and the grooves 1 7 into alignment. Naturally, the sealing means for the piston must also seal the grooves 1 7. Any number of noses 14 and corresponding grooves 1 7 may be provided, provided the amount of turning required to bring the axes of the eyes parallel leaves the noses 1 7 behind the shoulder 1 9. This is the amount 360 divided by 2n, where n is the number of noses. CLAIMS

3. A hydraulic piston/cylinder assembly as claimed in claim 1 or 2 wherein the piston has a plurality of said projection which are arranged symmetrically about the axis, and the cylinder a corresponding plurality of grooves.

4. A hydraulic piston/cylinder assembly as claimed in claims 2 and 3 wherein the piston must be turned by a circumferential angle 360 divided by 2n, where n is the number of projections, or a multiple of that angle, to bring the axes of the eyes into parallel.

5. A hydraulic piston/cylinder assembly as claimed in any preceding claim wherein both cylinder and piston are formed by coldflow pressings.

6. A hydraulic piston/cylinder assembly as substantially described herein.