IE87286B1 - An apparatus for washing of hydraulic cylinder workpieces - Google Patents

Abstract

An apparatus (1) is for washing large hydraulic cylinder workpieces (C). It supports a cylinder (C) at an angle with its open end facing downwardly and gripped by (75) which provide space for outflow of liquid which is pumped into the bore by a feed pipe (10). The feed pipe (10) remains static, which the workpiece is rotated by rotation of the gripping members (75) by a drive motor (24), belt (25), shaft and wheel (21), and bearing housing (20). The spend liquid is gathered in the housing (2), which provides a sump, and is re-circulated through a filter for re-use. After injection of liquid the feed pipe (10) is used to pump air for final drying.

Description

09/11/2021 - 1 “An Apparatus for Washing of Hydraulic Cylinder Workpieces” Introduction The present invention relates to washing of hydraulic cylinders.

Much of modern machinery is powered by hydraulic systems comprised of various elements such as pumps, valves, motors and cylinders. There is a continuous drive towards ever-cleaner circuits, as it is well established that cleaner systems lead to lower maintenance and longer machine life.

Smaller individual machined elements are relatively easy to clean and there are multiple wellknown methods and machines for such applications, but large assemblies present more challenges.

This is particularly true in the case of fabricated parts such as relatively large hydraulic cylinders, which often have ancillary parts such as oil feed pipes and valve blocks included in the barrel fabrications, and even more so in the case of relatively large cylinders. IE86311 (Byrne Family Technology partnership) describes an apparatus for cleaning multiple cylindrical workpieces which include various items on the outside diameter of the otherwise cylinder.

It is also known to provide equipment for washing cylindrical workpieces which have regular outside surfaces, such as pipes, as described in CN105396849 (A) (Tianjin), CN209318352 U (Liaoning), and CN212349758U (Shanghai).

The present invention is directed towards providing improved washing of hydraulic cylinders with irregular external profiles to a high standard.

Summary of the Disclosure The invention provides an apparatus for washing hydraulic cylinder workpieces having a bore and an open end, the apparatus comprising a housing forming a sump, a proximal workpiece support adapted to hold a cylindrical workpiece at its open end at a lower position than its closed end while allowing fluids to exit from the open end during washing, a distal support to hold the workpiece at the distal end so that it is clamped between the proximal and distal supports, and a feed pipe for delivery of pressurized washing liquid into the workpiece bore as it is being supported, and wherein the proximal support is adapted to rotate the workpiece during washing. -209/11/2021 The invention also provides a method of washing an hydraulic cylinder workpiece using such an apparatus, the method comprising clamping the workpiece between the proximal and distal supports, activating the proximal support to rotate and hence cause the workpiece to rotate with the distal support providing a clamping force but allowing workpiece rotation, injecting washing 5 liquids into the workpiece bore as the workpiece rotates and allowing the spent washing liquids to drain out of the mouth of the workpiece and into the tank.

Preferably, the proximal support is driven to rotate by a friction drive. Preferably, the proximal support comprises a plurality of gripping members for engaging the open end of a workpiece at 10 different circumferentially-spaced locations.

Preferably, the proximal support comprises a bearing housing of cylindrical shape and being driven by a drive to rotate while the gripping members which extend from the bearing housing engage a workpiece. Preferably, the gripping members are splayed outwardly in the distal direction from 15 the bearing housing, each at an acute angle to a longitudinal axis of the proximal support.

Preferably, the gripping arms are configured to engage a workpiece with its open end spaced-apart from other components of the proximal support to provide space for outflow of liquids from the workpiece. Preferably, the distal support comprises a ram with a rod having a tip for pressing 20 against a closed end of a workpiece.

Preferably, the tip is arrow-shaped for point contact with a workpiece closed end, preferably at a blind centering hole. Preferably, the apparatus comprises a mechanism for moving the distal support out of position to allow loading of a workpiece for washing.

Preferably, the proximal support supports the feed pipe. Preferably, the proximal support supports the feed pipe in a manner in which the feed pipe does not rotate.

Preferably, the proximal support comprises bearings around the feed pipe, the bearings supporting 30 the gripping members and a rotary drive component.

Preferably, the proximal and distal supports are configured to support a workpiece cylinder at an angle to horizontal in the range of 2° to 10°.

Preferably, the sump is provided by a closed tank. -3 09/11/2021 Preferably, the apparatus further comprises a spray device for spraying of external surfaces of a workpiece.

Preferably, the apparatus comprises means for supporting a piston of an hydraulic cylinder workpiece in a position to be washed by the spray device.

Preferably, the apparatus further comprises a skimmer for removal of floating debris including oil and grease.

Preferably, the apparatus comprises a feedback circuit with a filter for drawing spent liquid from the sump and pumping it after filtration back into the workpiece.

The method preferably comprises the further step of spraying external surfaces of the workpiece 15 during internal bore washing, and optionally a piston of the hydraulic cylinder may be also sprayed while being supported spaced-apart from the hydraulic cylinder.

Additional Statements We describe an apparatus for washing cylindrical workpieces, the apparatus comprising a housing 20 forming a sump, a workpiece support adapted to hold a cylindrical workpiece with its open end at a lower position than its closed end, and a feed pipe for delivery of pressurized washing liquid into the workpiece as it is being supported. Preferably, the sump is provided by a closed tank.

Preferably, the apparatus comprises a feedback circuit with a filter for drawing spent liquid from 25 the sump and pumping it after filtration back into the workpiece. Preferably, the workpiece support (5, 6) is adapted to rotate the workpiece during washing. Preferably, the workpiece support comprises a rotary support driven to rotate. Preferably, the rotary support is driven to rotate by a friction drive. Preferably, the rotary support comprises a plurality of gripping members for engaging the open end of a workpiece.

Preferably, the rotary support comprises a bearing housing of cylindrical shape and being driven by a drive to rotate while the gripping members engage a workpiece. Preferably, the gripping members are splayed outwardly from the bearing housing, each at an acute angle to a longitudinal axis of the bearing housing. 09/11/2021 -4Preferably, the gripping arms are configured to engage a workpiece with its end spaced-apart from the bearing housing to provide space for outflow of liquids from the workpiece.

In one example, the workpiece support comprises a clamp for engaging a workpiece at an end 5 opposed to the rotary support, and for allowing workpiece rotation. In one example, the clamp comprises a ram with a rod having a tip for pressing against a closed end of a workpiece. Preferably, the tip is arrow-shaped for point contact with a workpiece closed end, preferably at a blind centering hole.

In one example, the apparatus comprises a mechanism for moving the clamp out of position to allow loading of a workpiece for washing. Preferably, the rotary support supports the feed pipe.

In one example, the rotary support supports the feed pipe in a manner in which it does not rotate.

In one example, the rotary support comprises bearings around the feed pipe, the bearings supporting the gripping members and a rotary drive component. In one example, the apparatus is configured to support a workpiece cylinder at an angle to horizontal in the range of 2° to 10°.

Detailed Description of the Invention The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only with reference to the accompanying drawings in which: Fig. 1 is a diagrammatic side view of an apparatus for washing hydraulic cylinders, showing a cylinder (C) in position; Fig. 2 is an enlarged view showing engagement of the cylinder with a proximal support; Fig. 3(a) is an end view from the direction of a workpiece in use of the proximal support, and Fig. 3(b) is a perspective view of the proximal support; Fig. 4 is a diagram illustrating the drive in more detail; and Fig. 5 is diagram illustrating movement of a tailstock of the apparatus. 09/11/2021 - 5 Referring to Fig. 1 an apparatus 1 for washing hydraulic cylinders is shown. The apparatus 1 comprises a generally rectangular housing 2 forming a tank or sump mounted at a tilt to horizontal. This drawing shows a hydraulic cylinder workpiece C in position held against a rotational drive proximal support 5 at its open end, and at the opposite end it is retained in place by a distal support 5 comprising a tail clamping cylinder or tailstock 6. The tailstock 6 is shown in its operative position clamping the cylinder C, and in interrupted lines at its inoperative position (lower, as viewed in Fig. 1). The proximal support 5 supports a feed pipe 10 on its longitudinal axis in position extending into the bore of the cylinder C in use, and protection rings 11 and 12 prevent contact between the pipe 10 and the internal bore surface of the cylinder C in use.

The proximal support 5 comprises a gripper 15 integrally mounted to a bearing housing 20. A spherical bearing 30 is mounted externally of the housing 2 for supporting the bearing 20. The bearing housing 20 is driven by two (or more or in other examples) friction drive wheels 21 on drive shafts 22 which are mounted to the housing end wall 2 at one end and to a support 23 at the 15 opposite end, which supports are sealed against ingress of fluids contained within the tank 2. The drive shafts 22 are driven by a motor 24 driving a belt 25 in a triangular configuration as viewed in end view (Fig. 4).

The rotation of the proximal support 5, and hence of the hydraulic cylinder C, is provided by the 20 rollers 21 inside the tank. It is envisaged that in other embodiments the proximal support may be completely external of the tank, however it would still be beneficial to have a bearing support such as a passive cradle of rollers akin to the drive rollers 21.

The arrangement of the proximal support 5 is that the pipe 10 extends with a true support on-axis 25 with bearing support both internally and externally of the tank 2. The hydraulic cylinder C being washed is clamped between a gripper 15 of the proximal support 5 and the tailstock 6, the gripper having three splayed arms 75 separated equally by 120° and being integral with the bearing 20. The splayed arrangement widens in the distal direction into the tank, so that the proximal support 5 may engage any hydraulic cylinder having a diameter within the diameter defined by the distal30 most ends of the arms 75. At the other end the hydraulic cylinder C is pressed on-axis by the tailstock 6 towards the gripper 15. This is described in more detail below, but it will be apparent that the stroke of the tailstock 6 allows a wide variety of cylinder lengths to be accommodated, while the splayed arms at the proximal end allow a wide variety of diameters. Other features and advantages are set out below. -609/11/2021 The tank 2 has a width of about 800mm and a length chosen to suit the length of the workpiece hydraulic cylinders. It is configured to act as a sump for spent liquids used during washing.

While the internal diameter of the hydraulic cylinder C is uniformly cylindrical, on the outside it 5 frequently has various items, such as valve blocks, trunnions and other ancillary items welded to the otherwise circular outside diameter. As the cylinders are of various designs and sizes to suit the applications for which they are designed, these ancillary items may be situated at any point along the length. The existence of these external items means that the hydraulic cylinder C cannot be rotated or driven on its own surface. The apparatus 1 overcomes this problem. During the 10 washing operation, the fabrication is suspended between the three-pronged gripper 15 at the proximal, open, end, and the linear adjustable tailstock tip 7 at the distal end, the tip 7 engaging with a blind hole in the centre of the closing cap of the cylinder C. In this situation, the fabricated cylinder is suspended and clamped between the components 15/75 at the proximal end and 6/7 at the distal end. This is in a near horizontal attitude.

The gripper 15 is akin to a cone with most of its body cut away to leave the three segments or arms 75, which arrangement allows for the out flow of the washing liquid while the cylinder C is rotating. Also, the rotational energy is transmitted to the cylinder C via the gripper arms 75. The drive wheels 21 are spaced circumferentially apart to act as a cradle for the bearing housing 20 and 20 the friction drive between the knurled external surface of the bearing 20 and the drive wheels 21 transmits rotational energy from the pair of wheels 21 to the bearing 20, and thence via the arms 75 to the cylinder C. This arrangement solves the problem of rotating the fabrication (cylinder C) despite the existence of the external welded items on the outside of the fabrication, which is suspended between the three-pronged gripper 15 and the support centre provided by the tip 7.

The tailstock 6 comprises a hydraulic cylinder and piston rod with the tip 7 on a piston rod, to provide the energy to maintain the work piece in contact with the three-pronged gripper 15 during the washing/drying operation. The tailstock 6 has a relatively long stroke to accommodate the length variation within a range of hydraulic cylinders to be washed, without mechanical 30 adjustment. The tailstock 6 is mounted on a support mechanism 45 shown in Fig 4, which swings it about a pivot joint 50 into and out of its operative position in the plane of the page. In other examples this movement can be carried out without the use of a hydraulic cylinder 45, the movement can be done by the machine operator. The tailstock tip 7 is free-rotating, configured to maintain the hydraulic cylinder C in position and rotating during the washing/drying process. 09/11/2021 -7 The complete fluid feed assembly comprising the items 5, 10, 11, and 12, can ‘break away’ (or hinge up from) the drive wheels 21 when the tailstock 6 is withdrawn out of contact with the workpiece C. This feature serves to prevent accidental damage to the fluid feed assembly if there is an error when lifting the workpiece C from the machine with an overhead crane or other lifting means.

Figs. 4 and 5 show also a rod spray boom 60. There is also a skimmer which comprises a disc or belt which removes floating oil from the sump liquid overnight or at other periods when the liquid is at rest.

The boom 60 is used to shower wash the external surfaces of a piston rod 40 for the next cylinder as it is rotated on a cradle of rollers 41. The cylinder C is also washed externally by the boom 60 simultaneously with the inside as it rotates. The boom 60 is fitted with wide tee jets to facilitate the washing both the piston rod 40 and the cylinder barrel. This can be done simultaneously with the internal washing of the other cylinder C.

Fig. 2 illustrates in more detail the manner in which the proximal support 5 engages with a workpiece cylinder C. There are circlips 70 and 71 at the ends of the bearing housing 20, retaining bearings 72 and 73 for rotation of the bearing housing 20 about the feed pipe 10. Each gripping member or arm 75 has a cross-section as shown at the bottom of Fig. 2, with case-hardened wings 76 forming a nose for engaging the workpiece cylinder C.

The apparatus 1 is for use in cleaning fabricated cylinder barrels of relatively large diameter, having closed cylinder end caps/mounting brackets, and other features. It is particularly suitable for washing cylinders with a diameter above 120mm, because of combined rotational movement of the cylinder C and the large flow of liquid, which cascades along the inner surfaces of the cylinder C, from the high side to the lower side. The apparatus subsequently dries its interior, minimizing risk of small amounts of water mixing with the subsequent oil testing process. The drying is aided by two factors, one being that the liquid used is at a temperature of between 40°C to 60°C, and also by injection of high-pressure large flow air into the vessel after the wash cycle has finished.

The workpiece cylinder (“fabrication”) is mounted at a sloping angle from the horizontal plane within the range of 2° to 10° approximately. The open mouth of the cylinder fabrication is at the 09/11/2021 - 8 lower point (right hand, proximal, side as viewed in Fig. 1) and the closed end cap at the higher, distal, point (the left-hand side as viewed in Fig. 1).

Before commencing the automatic washing and drying cycle, any ancillary pipes and valve blocks are flushed-out with the fluid lance, to ensure there is no machining debris from earlier manufacturing process trapped inside.

An important aspect is that the protective sleeves 11 and 12, shown diagrammatically in Fig. 1, do not completely surround the feed pipe 10, rather they protect it from impact with the inside surface of the workpiece cylinder, and so protect this surface too. They thereby allow the feed pipe 10 to discharge under pressure a washing liquid with any desired composition, including detergent. The liquid is pumped from an external source coupled to the external end of the pipe 10 on the right as seen in Fig. 1. The liquid impinges on the blind end of the workpiece cylinder and flows under pressure with impingement against the internal surface of the cylinder, in the annular space around the feed pipe 10. Advantageously, the liquid flows with the slope out of the opening, and from there it is free to flow into the tank 2, which acts like a sump. This free flow is permitted by the fact that the open end of the cylinder C is gripped by the members 75 at a gap spaced apart from the bearing housing 20, and the gripping members 75 are circumferentially spaced apart.

Rotation of the workpiece C is allowed by the fact that the tailstock 6 has a free revolving rod end 7 in an arrow head configuration for point contact with the workpiece closed end, which has a blind centering hole, thereby allowing it to rotate.

The delivery of washing liquid can be followed by pressurized air or other gas to dry the internal surfaces.

Another major advantage is that the workpiece cylinder C is rotating while the liquids and gases are pumped, thereby helping to facilitate the thoroughness of cleaning. This drive is provided by the drive motor 24 via the mechanism 21/22/25. The tail clamping cylinder 7 only grips at a point, and so allows rotation.

In more detail, while the cylinder fabrication (C) is rotating, a copious volume of heated fluid, dosed with a suitable detergent is fed by means of the mounted hollow feed pipe 10 into the inside of the cylinder and delivered from the said feed pipe at a point close to the closing end cap at the distal end. The fluid can flow down and out through the open mouth of the cylinder fabrication C -909/11/2021 at a rapid flow rate. This rapid flow, together with the chemical action of the hot, dosed fluid acts to remove all particles and oily/greasy contaminants, which, may be present from prior manufacturing processes. This cleaning action is enhanced by the rotating action, as the spent fluids flow rapidly along the lower quadrant of the cylinder, which is constantly changing and 5 therefore reaches all surfaces and cavities as fluid may enter the latter at the bottom quadrant and flow out as it rotates to the upper quadrant.

The out-flowing fluid is recycled into the holding tank 2 underneath the revolving mechanism, where it is kept at a temperature of between 40°C to 60°C. An outlet from the tank 2 directs the 10 liquid to a centrifugal pump (not shown) which in turn directs it to a relatively coarse (10pm) filter and further to a finer filter, of size 3 pm to 5 pm. The liquid is then returned back into the rotating cylinder fabrication C and this recycling continues for the duration of the timer-controlled washing process.

As the above internal cleaning of the fabricated cylinder is taking place the external surfaces of the same fabricated cylinder are showered with the same filtered liquid thereby cleaning the outside surfaces.

After the washing process is completed, the cylinder fabrication C continues to rotate. With the 20 aid of timers and valves, the fluid flow is stopped and is followed by a forced flow of filtered compressed air, which is fed through the same fluid pipe 10. The air flow acting together with the hot metal dries away any remaining liquid from the inside of the cylinder C and all ancillary piping and other cavities attached to the fabrication C.

The fluid feed pipe 10 does not rotate. It is mounted in such a manner that, in the event of the operator lifting the fabrication C too high with heavy lifting gear, the feed pipe 10 can pivot upward in order to avoid possible bending of the pipe itself.

The cylinder C is maintained in a central position by means of the splayed gripping members 75 30 at the open-mouthed end and by the free- revolving tailstock assembly and hydraulic cylinder 6/7 at the closed cap end. The support members 75 are mounted on stainless steel bearings 73, which are in turn mounted on the feed pipe 10. This gripper 15 with the gripping members 75 and the housing 20 are driven by the geared-motor 24 via the two friction rollers 21, which impart the rotary action to the cylinder fabrication C. It is this friction drive mechanism which facilitates the 35 above -mentioned ‘break-away’ facility to avoid operator error and possible feed pipe 10 bending. - 1009/11/2021 As shown in Fig. 5 the tailstock clamp 6 can be rotated between operative and inoperative positions for loading and operation. These positions are caused by action of the actuator ram 45 which is pivoted on a joint 46 and engages the tailstock 6 at a pivot joint 47.

The holding tank 2 is fitted with heating elements and the oil skimming unit to keep the fluid free from oil contamination.

The whole unit is sufficiently narrow to allow installation beside an assembly operation and this 10 in turn, facilitates the washing/drying operation to take place while the same operator is assembling the preceding cylinder.

Advantageous features include the following: The cylinder fabrication C is mounted at an angle from the horizontal with open end at 15 lowest point.

The cylinder C rotates while heated, dosed and filtered fluid is delivered via the feed pipe 10 toward the higher closed end cap end, and cascades rapidly and out through the cylinder mouth, carrying any debris from earlier machining and fabrication processes.

All external surfaces of the cylinder fabrication are showered with the same liquid, thereby 20 cleaning the outside at the same time as cleaning the inside.

The cylinder C continues to rotate while filtered compressed air is delivered via the same feed pipe, again toward higher closed end cap end, drying the complete vessel.

Provision of a friction drive to facilitate ‘break-away’ in the event of operator error when unloading.

Non-rotating feed pipe 10 can ‘break-away’ from friction drive.

Feed pipe is extendable for longer cylinder fabrications.

Tail support is extendable for shorter cylinder fabrications.

No mechanical adjustment required for different diameter cylinder fabrications within design range.

The invention is not limited to the embodiments described but may be varied in construction and detail within the scope of the claims. It is preferred that the workpiece be gripped so that its open end is lowest and liquids drain out, but this is not essential. Even where the open end of the workpiece is lowest it is not essential that the tank be tilted, as the gripping components could be 35 mounted in the tank in a tilted manner.

Claims (21)

1. 09/11/2021 Claims

1. An apparatus for washing hydraulic cylinder workpieces having a bore and an open end, the apparatus comprising a housing (2) forming a sump, a proximal workpiece support (5, 5 15) adapted to hold a cylindrical workpiece (C) at its open end at a lower position than its closed end while allowing fluids to exit from the open end during washing, a distal support to hold the workpiece at the distal end so that it is clamped between the proximal and distal supports, and a feed pipe (10) for delivery of pressurized washing liquid into the workpiece bore as it is being supported, and wherein the proximal support (5) is adapted to rotate the 10 workpiece during washing.

2. An apparatus as claimed in claim 1, wherein the proximal support (5) is driven to rotate by a friction drive (21, 20, 22). 15

3. An apparatus as claimed in claim 1 or claim 2, wherein the proximal support comprises a plurality of gripping members (75) for engaging the open end of a workpiece (C) at different circumferentially-spaced locations.

4. An apparatus as claimed in claim 3, wherein the proximal support (5) comprises a bearing 20 housing (20) of cylindrical shape and being driven by a drive (24, 21, 25) to rotate while the gripping members (75) which extend from the bearing housing engage a workpiece (C).

5. An apparatus as claimed in claims 3 or 4, wherein the gripping members (75) are splayed outwardly in the distal direction from the bearing housing (20), each at an acute angle to a 25 longitudinal axis of the proximal support (5, 20).

6. An apparatus as claimed in claim 5, wherein the gripping arms (75) are configured to engage a workpiece with its open end spaced-apart from other components of the proximal support to provide space for outflow of liquids from the workpiece.

7. An apparatus as claimed in any preceding claim, wherein the distal support comprises a ram (6) with a rod having a tip (7) for pressing against a closed end of a workpiece.

8. An apparatus as claimed in claim 7, wherein the tip is arrow-shaped for point contact with 35 a workpiece closed end, preferably at a blind centering hole. - 1209/11/2021

9. An apparatus as claimed in any preceding claim, wherein the apparatus comprises a mechanism (45) for moving the distal support (6, 7) out of position to allow loading of a workpiece for washing.

10. An apparatus as claimed in any preceding claim, wherein the proximal support (5) supports the feed pipe (10).

11. An apparatus as claimed in claim 10, wherein the proximal support (5) supports the feed 10 pipe (10) in a manner in which the feed pipe does not rotate.

12. An apparatus as claimed in claim 11, wherein the proximal support (5) comprises bearings (72, 73) around the feed pipe, the bearings supporting the gripping members (75) and a rotary drive component (20).

13. An apparatus as claimed in any preceding claim, wherein the proximal and distal supports are configured to support a workpiece cylinder (C) at an angle to horizontal in the range of 2°to 10° 20

14. An apparatus as claimed in any preceding claim, wherein the sump is provided by a closed tank (2).

15. An apparatus as claimed in any preceding claim, further comprising a spray device for spraying of external surfaces of a workpiece.

16. An apparatus as claimed in claim 15, wherein the apparatus comprises means for supporting a piston of an hydraulic cylinder workpiece in a position to be washed by the spray device. 30

17. An apparatus as claimed in any preceding claim, further comprising a skimmer for removal of floating debris including oil and grease.

18. An apparatus as claimed in any preceding claim, wherein the apparatus comprises a feedback circuit with a filter for drawing spent liquid from the sump and pumping it after 35 filtration back into the workpiece.

19. A method of washing an hydraulic cylinder workpiece using an apparatus of any preceding claim, the method comprising clamping the workpiece between the proximal and distal supports, activating the proximal support to rotate and hence cause the workpiece to rotate 5 with the distal support providing a clamping force but allowing workpiece rotation, injecting washing liquids into the workpiece bore as the workpiece rotates and allowing the spent washing liquids to drain out of the mouth of the workpiece and into the tank.

20. A method as claimed in claim 19, comprising the further step of spraying external surfaces 10 of the workpiece during internal bore washing.

21. A method as claimed in claim 20, wherein a piston of the hydraulic cylinder is also sprayed while being supported spaced apart from the hydraulic cylinder. CM