Hydraulic Cylinder

Abstract

A hydraulic cylinder having a cylindrical sleeve with a closure wall on the end including a seal and a resilient lock element removably positioned to fix the axial position of the wall relative to the sleeve.

Description

This invention relates to a hydraulic actuator and more particularly to a hydraulic cylinder having a cylindrical sleeve with a head forming an end wall which is fastened together by a single resilient deformable locking element to maintain the axial position of the head in the cylindrical sleeve.

With the increased use of hydraulic cylinders in hydraulic systems, a low unit cost for each cylinder is becoming increasingly important. By simplifying the component structure, reducing the machining operations and using a relatively few number of parts which can be easily assembled and disassembled, a substantial economy can be achieved. The conventional threaded construction or welded construction head in the cylindrical sleeve for assembly and disassembly of the hydraulic cylinder can be eliminated.

Accordingly, this invention provides a cylindrical sleeve for receiving the head portion defining the end wall of the hydraulic cylinder. Either one or both ends of the hydraulic cylinder can be constructed in this manner. The head or cylindrical sleeve define an annular recess for receiving a seal element to seal the hydraulic fluid in the hydraulic cylinder. Another annular groove is formed in a portion of the cylindrical sleeve which is aligned with the mating annular recess formed in the external periphery of the head. The head also is formed with an axial opening for a limited peripheral portion to accept an instrument for removing a deformable resilient element such as the snapring in the groove and recess of the cylindrical sleeve and head. In this manner a single deformable resilient element locks the axial position of a cylindrical head in the cylindrical sleeve to provide a simple convenient means of manufacturing and assembly of a hydraulic cylinder.

It is the object of this invention to provide a hydraulic cylinder having a cylindrical sleeve and receiving a head in which a resilient and deformable element locks the sleeve axially to the head.

It is another object of this invention to provide a hydraulic cylinder assembly having a cylindrical sleeve receiving a cylindrical head with a deformable resilient element received in mating grooves of the sleeve and head to lock the head relative to the cylindrical sleeve while simultaneously sealing the two elements with a sealing means.

It is a further object of this invention to provide a hydraulic cylinder assembly having a cylindrical sleeve and a cylindrical head received therein. The head and sleeve define annular recesses axially aligned with each other to receive a snapring with access means in the head to permit unlocking of the snapring for disassembly of a hydraulic cylinder.

The objects of this invention are accomplished by providing a cylindrical sleeve with a machined inner surface to receive a machine head forming of a mating external surface. The internal periphery of the cylindrical sleeve and the external periphery of the cylindrical head each define a mating groove for simultaneously receiving a portion of an expandable element such as the snapring to lock the sleeve and head axially. An opening for a limited portion of the periphery of the head permits the insertion of a tool for contraction of a snapring for disassembling of the hydraulic cylinder. Suitable sealing means are provided between the head and cylindrical sleeve for sealing of the hydraulic cylinder.

Referring to the drawings,

FIG. 1 illustrates a cross section view of the hydraulic cylinder.

FIG. 2 illustrates a cross section view of the hydraulic cylinder taken on line II--II of FIG. 1.

FIG. 3 is a cross section view taken from line III--III of FIG. 1.

Referring to the drawings, FIG. 1 shows a piston 1 having a shank 2 defining an opening 3 for receiving a pin for a mechanism not shown. The piston 1 defines an annular depression 4 which receives the ring 5. The ring 5 engages a beveled surface 6 on the inner periphery of the cylindrical sleeve 7.

The cylindrical sleeve 7 also forms a groove 8 and a groove 9 for receiving seals 10 and 11. The piston 1 reciprocates within the sleeve as the hydraulic cylinder is operated. A portion of the sleeve and the cylinder is shown broken away.

The sleeve 7 is also formed with a bevel surface 12 on the other end and also defines a groove 13 for receiving the snapring 14. The recess 15, on the external periphery of the head 16, receives the seal 17. The head 16 is positioned within the cylindrical sleeve 7 and forms an end portion 18 defining a pinhole 19 for attachment to an external device.

The head 16 forms a drilled passage 119 in communication with the axial passage 20 leading to the pressurized chamber 21 within the hydraulic cylinder. The beveled surface 22 adjoins the groove 13 in the end of the cylindrical sleeve 7. The radial surface 24 prevents the head 16 from moving axially to the right beyond the predetermined position. When the snapring 14 is contracted to a centered position the head can be easily withdrawn from the sleeve to disassemble the hydraulic cylinder.

Referring to FIG. 2 the head is shown in a cross section view positioned in the hydraulic cylinder. The passages 119 and 20 are formed in the head.

FIG. 3 is a cross section view taken adjacent to the snapring 14 which shows the cylinder in the assembled position. The particular configuration of the ring is not of equal radial thickness throughout the length of the snapring 14. The snapring has a radial thickness at its center portion which is slightly less than the radial thickness of the ears 30 and 31. The radial thickness of the ring 14 tapers from the center portion 32 to a point adjacent to the ears 30 and 31. This causes the ring to retain a substantially circular shape on its external periphery as the ears 30 and 31 are contracted by inserting a tool in the openings 33 and 34.

The groove 13 is of circular figuration having a center concentric with the sleeve 7. The circle formed by the external periphery of groove 13 is centered at 35. The internal periphery of the recess 50 in head 16 is also circular but the center defined by the inner periphery recess 50 is centered about the center point 37. With an eccentric relationship of the inner periphery of recess 50 and outer periphery of groove 13, the points 38 and 39 are closer to the external periphery 40 of groove 13 than the point 41. Because of this relationship and the radial thickness of ears 30 and 31, the ring 14 cannot freely rotate within the groove 13 because the ears 30 and 31 will engage the points 38 or 39 to prevent rotation.

The hydraulic cylinder is assembled by placing the seals 10 and 11 in the grooves 8 and 9 and then inserting the piston 1 with the snapring 5 positioned thereon within the sleeve 7 from the left end. The head is assembled by positioning the seal 17 in the groove 15 and also positioning the snapring 14 in the recess 50 and retaining the snapring in a contracted position by inserting a tool in the holes 33 and 34 of the ears 30 and 31 and maintaining this contracted position as the head is inserted within the end of the sleeve 7. The bevel surface 12 assists in concentrically aligning the snapring 14 within the recess 50 as the snapring rides under the beveled surface 12 into the cylindrical opening 23 of sleeve 7. The head is moved in the right-hand direction until the snapring 14 aligns itself in the annular groove 13 in the sleeve 7. When the recess 50 and the groove 13 are in alignment, the snapring 14 is released and permitted to expand to partially position itself within the groove 13 and the recess 50. The snapring expands radially and the partial seating of itself within the groove 13 and recess 50 firmly locks the sleeve 7 to the head 16 to retain this fixed axial position.

The snapring 14 is tapered from its center portions to the ears 31 and 30, the taper is provided to maintain a circular configuration of its outer periphery as the snapring 14 expands.

The hydraulic cylinder is disassembled by inserting a tool axially within opening 45 and engaging the openings 33 and 34. The ring is contracted by moving the ears 31 and 30 together. Due to the unequal radial thickness of the ring, although a greater stress is placed on the center portion, the ring maintains a circular outer periphery. The centering of the ring can be further augmented by forcing the head 16 slightly inwardly causing the snapring 14 to center itself on the bevel surface 22. When the snapring 14 is centered within the opening 23 of the sleeve 7 it can then be withdrawn completely from the opening by withdrawing the head 16 in the opposite direction. This in turn permits removal of the piston and complete dismantling of the hydraulic cylinder. Any parts which need replacing can be replaced and the cylinder reassembled in a manner as previously described.

Claims

The embodiments of the invention in which an exclusive property of privilege is claimed are defined as follows:

1. A hydraulic cylinder comprising a cylinder sleeve defining an internal concentric annular groove on the end portion thereof, an external peripheral surface forming the external periphery of said groove, a head received within said sleeve defining an eccentric annular recess on its external periphery, a circular inner peripheral surface forming the internal periphery of said recess, a deformable resilient ring element expanded to continuously engage the periphery of said annular groove positioned partially in said groove and said recess to axially lock the head and sleeve, said resilient ring having end portions which define ears of greater radial thickness than the combined radial depth of said groove and recess to thereby prevent rotation of said ring relative to said head, said resilient ring defining an internal peripheral surface substantially concentric with the circular surface of said recess, said head defining an opening extending axially from the external side of said head to permit access for deforming said ring element to permit disassembly of said hydraulic cylinder.

2. A hydraulic cylinder as set forth in claim 1 wherein said head defines an axial extension of a limited peripheral portion of said annular recess to form said opening.

3. A hydraulic cylinder as set forth in claim 1 wherein said ring element defines an ear on each end portion received in said opening of said head adapted for engagement with a tool to contract said ring element.

4. A hydraulic cylinder as set forth in claim 1 wherein said ring element defines a ring of nonuniform radial thickness wherein the center portion tapers to a thinner radial thickness of the end portions.

5. A hydraulic cylinder as set forth in claim 1 wherein said annular recess in said head defines said inner peripheral surface for engaging said ring element when said ring element is contracted for aligning said ring element within said recess when said hydraulic cylinder is assembled or disassembled.

6. A hydraulic cylinder as set forth in claim 1 wherein said head defines a groove, a seal received in said groove engaging said sleeve to thereby seal said head with said sleeve hydraulically.

7. A hydraulic cylinder as set forth in claim 1 wherein said ring element defines an ear on each end of said ring, each of said ears defining a hole for reception of a tool to thereby contract said ring for disassembly of said hydraulic cylinder.

8. A hydraulic cylinder as set forth in claim 1 wherein said resilient ring element defines a substantially radially thicker center portion with tapered end portions.

9. A hydraulic cylinder as set forth in claim 1 wherein said ring element defines ears on its end position for reception in said opening, said head forming said eccentric recess with the point on the inner peripheral surface adjacent said opening the closest to said cylinder sleeve, said ears on said ring element having greater radial than the combined radial depth of said groove and said recess to thereby prevent said ring from rotating beyond said opening in said head.