US3730057A

US3730057A - Hydraulic ram assembly

Info

Publication number: US3730057A
Application number: US00139556A
Authority: US
Inventors: J Friden
Original assignee: MFG MANUF CO
Current assignee: MFG MANUF CO
Priority date: 1971-05-03
Filing date: 1971-05-03
Publication date: 1973-05-01
Anticipated expiration: 1990-05-01

Abstract

A hydraulic ram is assembled from a first tubular member having a plug inserted in fluid tight relation in one end thereof and a second tubular member, defining the actuator rod of the ram, mounted for reciprocation in the first tubular member with one end thereof adjacent the plug and the other end thereof extending beyond the open end of the first tubular member. A second plug member is inserted in the exposed end of the actuator rod in fluid tight relation therewith and seal means is mounted in the first tubular member adjacent its open end to prevent fluid loss during reciprocation of the actuator. The plug in the actuator rod defines a piston surface therein against which fluid supplied to the ram assembly, through a port in the first mentioned plug, acts to extend the actuator rod.

Description

United States Patent 1 Friden [451 May1,1973

[73] Assignee: MFG Manufacturing Co., Martinsville, NJ.

[22] Filed: May 3, 1971 [21] Appl. No.: 139,556

[52] US. Cl. ..92/110, 29/1546, 92/163, v 92/168, 92/169 [51] Km. Cl ..FOlb 31/00, F16j 11/02, 1323p 15/00 [58] Field of Search ..92/110, 128, 165, 92/168, 163,164, 169, 52, 53; 29/1564 [56] References Cited UNITED STATES PATENTS 2,661,721 12/1953 Sherwen ..92/163 2,836,443 5/1958 Farmer ..92/168 X 2,899,938 8/1959 Gardner ..92/168 X 2,942,582 6/1960 Dempster et a1. ..92/168 3,007,723 ll/l961 Clarke ..92/168 X 3,335,642 8/1967 Rosaen ..92/165 X 3,343,460 9/1967 Jones ..92/168 FOREIGN PATENTS OR APPLlCATlONS 562,073 6/ 1944 Great Britain ..92/ 164 Primary Examiner1rwin C. Cohen Att0rney-Lewis 1-1. Eslinger, Alvin Sinderbrand and Curtis, Morris & Safiord 5 7 ABSTRACT A hydraulic ram is assembled from a first tubular member having a plug inserted in fluid tight relation in one end thereof and a second tubular member, defining the actuator rod of the ram, mounted for reciprocation in the first tubular member with one end thereof adjacent the plug and the other end thereof extending beyond the open end of the first tubular member. A second plug member is inserted in the exposed end of the actuator rod in fluid tight relation therewith and seal means is mounted in the first tubular member adjacent its open end to prevent fluid loss during reciprocation of the actuator. The plug in the actuator rod defines a piston surface therein against which fluid supplied to the ram assembly, through a port in the first mentioned plug, acts to extend the actuator rod.

18 Claims, 1 Drawing Figure HYDRAULIC RAM ASSEMBLY This'invention relates to a hydraulic ram assembly and more particularly to a simplified cylinder and piston construction and a method for fabricating the ram assembly.

The hydraulic rams which have previously been proposed in the art normally employ cylinders formed of tubular steel construction joined with steel end caps by rather elaborate constructions. Traditionally, these rams are relatively expensive to produce and require a substantial amount of machine work due to the high tolerances required in mating the various parts. Thus, the cylinder, actuator rod and piston must each be turned or milled, in order to assure proper fit and sliding movement therebetween. Further, in numerous arrangements various elements of the hydraulic ram are either threaded together, thereby requiring finely controlled threading operations or welded together, thereby requiring an additional skilled worker and excess and expensive equipment.

Hydraulic rams of the above type are normally relatively expensive and it is desirable to produce rams of high quality which are efficient in operation by a process which is economical. Consequently, as few a number of manufacturing steps as possible must be utilized to assemble the various parts.

Accordingly, it is an object of the present invention to provide an efficient high fluid pressure hydraulic ram device that may be readily assembled and variably mounted.

it is another object of the present invention to fabricate a hydraulic ram by a process which is both simple and inexpensive to perform.

Yet another object of the present invention is to provide a hydraulic ram which is relatively simple in construction and relatively inexpensive and simple to construct.

Yet another object of the present invention is to fabricate a hydraulic ram by utilizing a minimum number of parts.

In accordance with an aspect of the present invention a hydraulic ram is fabricated by cutting a first cylindrical tubular member to the desired length and expanding one end thereof so that that end has a larger inside diameter than the remainder of the tube. An annular fluid seal and wiper assembly is inserted in the expanded end of the cylindrical tube and is held in place by a snap ring mounted in the tube. A second cylindrical tubular member, having a smaller outside diameter than the inside diameter of the first cylindrical tubular member is then cut to the desired length and one end thereof is expanded so that its outside diameter is approximately the same as the inside diameter of the first tubular member. This second tubular member comprises the actuator rod of the completed hydraulic ram assembly and has a plug secured in fluid tight relation with the non-expanded end thereof. The actuator rod is then inserted into the first tubular member through the non-expanded end thereof with the plugged end of the actuator rod extending'through the seal member and beyond the expanded end of the first tubular member. Thereafter, a plug, having an axially extending fluid supply port-therein, is inserted in fluid tight relation with the unexpanded end of the first tubular member so as to define a fluid chamber between that plug and the seal means in the expanded end of the first tubular member. Fluid supplied to the interior of the first tubular member through the port in its plug will fill the fluid chamber and the tubular actuator rod and this fluid will act against the plug in the non-expanded end of the actuator rod to extend the rod. As the actuator rod is moved outwardly of the first tubular member, which defines the cylinder of the hydraulic ram, the expanded end of the actuator rod acts as a guide and provides stable movement of the rod along a straight line path.

The above, and other objects, features and advantages of this invention will be apparent in the following detailed description .of an illustrative embodiment thereof, which is to be read in connection with the accompanying drawing wherein the single FIGURE is a sectional view taken along the longitudinal axis of a hydraulic ram assembly constructed in accordance with the method of the present invention.

Referring to the drawing in detail, it will be seen that a hydraulic ram assembly 10 embodying the present invention, as shown therein, includes an outer cylindrical tubular member 12 and an inner cylindrical tubular actuator rod 14 which is to be extended with respect to the tubular member 12, i.e. the cylinder of the ram assembly, by fluid supplied to the cylinder, as is more fully described hereinafter.

In fabricating hydraulic ram 10, cylinder 12 is initially cut from a supply of steel tubing to the desired length for the completed ram assembly. The end 16 of tubing member 12 is then machined with an internal groove 18 which later receives a snap or retainer ring for the sealing member and bearing utilized in the ram assembly. After the grooving operation is completed, end 16 is expanded in a power press by a conventional process so that the interior diameter thereof is increased with respect to the remainder of the tubing section. It is noted that the interior surface 17 of tube end 16 is grooved prior to the expanding process in order to take advantage of the inherent concentricity of the tubing, which concentricity may be lost during the expansion process.

A bearing 20 is inserted within the tube end 16 for guiding actuator 14 during reciprocation in the completed ram assembly. The bearing is initially cut to the desired length-from a supply of tubing having an outside diameter which is approximately the same dimension as the inside diameter of the expanded section 16. The cut bearing section is then swaged in a power press to increase and smooth its inside surface 22 while simultaneously increasing its outside diameter so that it will interference fit with the inner surface 17 of end section 16. Alternatively, bearing 16 may be formed to slip fit within tube section 16 to facilitate its repair or removal if necessary. In both cases and particularly where bearing 16 is slip fit, the position of the bearing is maintained by assembly 26 more fully described hereinafter.

The surface 24 of bearing 20 and the entire inner surface of tube 12 are then cleaned by a conventional degreasing process and a self-curing adhesive, which in the preferred embodiment is an anaerobic adhesive, is applied to the exterior surface of bearing 20. The bearing is then inserted in the end 16 of tube 12 which tube is mounted in a press, and the assembly is permitted to cure until the adhesive is set. Therafter, the combination seal, wiper and shap ring assembly 26 is inserted in end 16 to prevent fluid loss through the open end 28 of the completed ram assembly.

Assembly 26 includes an annular seal 30 which is placed in tube end 16 against the leading edge 32 of bearing 20. In one embodiment of the present invention a QUAD-X type seal obtainable from the Minnesota Rubber Company, Minneapolis, Minn. has been satisfactorily employed for this purpose. After seal 30 is seated, a wiper 34 is inserted in end 16 against the seal, which wiper is an annular polyurethane ring of conventional construction that serves to remove any dirt on the actuator rod 14 when it is being retracted into cylinder 12. The wiper, in addition, acts as a back up washer about actuator 14 for high pressure applications and, since there is zero clearance between the wiper and rod 14, the wiper acts as a non-scoring centering device for the rod as it is retracted.

After the wiper 30 is inserted an annular washer 36 is placed against the leading surface 38 of wiper 34 and a snap ring 40 is mounted in groove 18 to retain the assembly of washer, wiper, seal and bearing in expanded tube end 16. The snap ring 40 is a conventional cadmium plated steel ring such as those obtainable from the Waldes Kohinoor Company, Inc.

Actuator rod 14 is fabricated either before or after the bearing and seal assembly 26 are mounted in expanded end 16 of tube 12. As seen in the drawing, actuator rod 14 is a cylindrical tubular member and this member is cut from a length of steel tubing having an outside diameter that is slightly smaller than the inside diameter of the non-expanded section of cylinder 12. The tube 14 is cut to substantially the same length as cylinder 12 and its exterior surface may thereafter be ground ,in a single pass to clean the surface and/or make it smoother for better sliding movement in cylinder 12. In the preferred embodiment of the present invention the outer surface of actuator rod 14 is hard chrome plated and polished prior to insertion in cylinder 12 to provide the ram assembly with the look of a finely finished high quality product and to further improve the sliding movement of the actuator rod within cylinder 12.

After tube 14 is cut and ground, the end 42 thereof is expanded in a power press so that its outside diameter is increased to substantially the same dimension as the inside diameter of the non-expanded portion of cylinder 12. In the completed ram assembly, as illustrated in the drawing, expanded section 42 of actuator rod 14 acts as a guide during movement of the actuator into and out of the cylinder 12. The section 42 cooperates with bearing 20 to stabilize the movement of the actuator rod. In addition, surface 42 constitutes a wear surface for the actuator rod and its engagement with surface 44 of bearing 20 will define the outermost limit of possible extension of actuator rod 14, since the bearing will prevent further lateral movement of the actuator out of cylinder 12.

After end 42 has been expanded, a cylindrical solid steel plug 46 is cut from a supply of steel rod having a diameter substantially equal the inside diameter of actuator rod 14 and the exterior surface 48 of plug 46 and the interior surface 50 of actuator 14 are cleaned by a conventional degreasing process. The surface 48 is thereafter treated with a primer and a self-curing,

v the seal and wiper assembly 26.

Plugs

46 and 60 cannot.

be disconnected from actuator 14 or cylinder 12 preferably anaerobic, adhesive and the plug is then inserted in the end 52 of actuator 14 in an interference fit. This assembly is then permitted to cure until the adhesive has set.

After the adhesive utilized to bond plug 46 to the surface 50 of actuator 14 has set, the plug 46 and actuator rod 14 are cross-drilled to provide a bore 54 which extends entirely through the actuator rod 14 and plug 46 along a line substantially perpendicular to the longitudinal axis of the ram assembly. This bore acts as a mounting hole for the actuator rod in the completed hydraulic ram assembly.

.When the actuator rod 14 and cylinder 12 are completely assembled, as thus far described, the actuator rod is inserted into cylinder 12 through its end 58 and through the seal assembly 26 until the end 52 of the rod extends beyond the end 28 of the cylinder, as illustrated in the drawing, With the cylinder and actuator thus assembled, a plug 60 is cut to the desired length from a steel rod supply having an outside diameter substantially equal to the inside diameter of tube end 58. The plug is then drilled with an axial port 62 in its interior face 64. Thereafter, the interior surface of cylinder end 58 and the exterior surface of plug 60 are both cleaned by a degreasing process and a primer coat and self-curing anaerobic adhesive is applied to plug 60. The plug is then press fit in tube end 48 and permitted to cure until the adhesive has set.

After the adhesive utilized to bond plug 60 to tube end 58 has set, a work hole 66, corresponding to the work hole 54, is drilled through cylinder end 58 and plug 60. This hole receives a bolt or the like to mount the cylinder during use of the completed hydraulic ram assembly.

After bore 66 is drilled, another bore 68 is drilled substantially perpendicularly to bore 66 with one end 70 thereof in communication with bore 62. These bores permit entrance of hydraulic fluid into the interior of the fluid chamber 72 of the ram, which chamber is defined between the innermost surface 64 of plug 60 and the seal 20. In the preferred embodiment of the present invention the bore 70 is provided with a port plug 74 secured in bore 70 by a self-curinganaerobic adhesive similar to that used in the other steps of the process. Plug 74 has an internally threaded bore 76 that is adapted to threadedly receive the fitting on the end of a fluid supply line (not shown). After the adhesive securing plug 74 in place is cured, the ram assembly is ready for operation. Plug 74 in addition; acts as a key to keep cylinder 12 and plug 60 in a fixed relative position and resists any tendency of one to move relative to the other because it is engaged with both of these members.

In operation a fluid supply line is connected to fitting 74 and fluid is supplied to chamber 72 through the fitting and bore 62. Chamber 72 is filled and fluid flows into the interior bore 78 of actoator l4 and acts against the interior surface 80 of plug 46. It is thus seen that plug 46 acts as the piston in the hydraulic ram assembly even though it is not itself within the cylinder 12 as would be the case in conventional ram constructions. Leakage of fluid from the ram is prevented by the fluid tight seal between plug 60 and tube section 58 and by respectively, as the cross pins used to mount the two ends of the ram during operation of the complete assembly engage both the plug and its associated tubular member. As a result, an equal force is applied to both the plugs and the tubes so that the cross pins will themselves act as safety pins to retain the cylinder plug 60 and piston plug 46 within their associated tubular members even under extreme shock and overloading conditions.

In another embodiment of the present invention it is contemplated that rod 14 may be formed with a plug secured in its end 42. In this embodiment, the plug in end 42 would act as the piston against which fluid in cylinder 12 would act. The arrangement is advantageous in that a smaller amount or volume ofliquid is therefore required to actuate the cylinder.

It is thus seen that a relatively simply constructed hydraulic ram assembly of exceptional quality is provided by a relatively simple fabricating process. The cost of performing the fabricating process described above is substantially reduced because of the utilization of press operations for the ends of the tubes, press fitting of adjacent parts and the use of adhesives for sealing and locking adjacent parts together in lieu of the more traditional and expensive operations of turning, milling, threading, welding and the like.

Although an illustrative embodiment of the present invention has been described herein with reference to the accompanying drawing, it is to be understood that the invention is not limited to that precise embodiment and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of this invention.

What is claimed is:

l. A hydraulic ram assembly comprising a first tubular member, plug means inserted in one end of said tubular member in fluid tight relation therewith and having a port therein providing fluid communication to the interior of the tubular member, a second tubular member defining the actuator rod of said ram and being reciprocally mounted in said first tubular member, with one end thereof adjacent said plug means and the other end thereof extending from said first tubular member, and plug means inserted in said other end of the actuator rod in fluid tight relation therewith, said first and second tubular members being generally cylindrical members, and said one end of said actuator rod being expanded to have a larger outside diameter than the remainder thereof, said outside diameter being substantially equal to the inside diameter of said first tubular member whereby said expanded one end of said actuator rod comprises guide means for the rod; the other end of said first tubular member being expanded to have a larger inside diameter than the remainder thereof, and seal means mounted in said other end of said first tubular member, said seal means including a snap ring, an annular wiper ring mounted adjacent said snap ring and inwardly thereof with respect to said other end of said first tubular member, and an annular sealing ring mounted adjacent said wiper, thereby to prevent fluid loss from said ram assembly during reciprocation of said actuator.

2. The assembly as defined in claim 1 wherein said plug means in said actuator rod defines a piston surface in said actuator rod against which fluid supplied to said ram assembly through said port acts to extend the rod.

3. An assembly as defined in claim 2 wherein said seal means also includes an annular washer mounted between said wiper and said snap ring.

4. An assembly as defined in claim 3 wherein said other end of said first tubular member has an annular groove formed therein, said snap ring being mounted in said groove for retaining said wiper and sealing ring in said first tubular member.

5. An assembly as defined in claim 4 including an annular bearing mounted in said other end of said first tubular member inwardly of and adjacent said annular sealing means for slidably receiving said actuator rod to guide said rod during movement thereof.

6. An assembly as defined in claim 5 wherein said first tubular member includes an aperture therein in axial alignment with said port and a port plug secured in said aperture and said port for keeping said first tubular member and its associated plug means together.

7. An assembly as defined in claim 6 wherein said port plug has an internally threaded bore communicating with said port and being adapted to be threadedly engaged with a fluid supply line fitting.

8. An assembly as defined in claim 5 wherein said first tubular member and its associated plug means have a mounting aperture formed therein substantially perpendicularly of the longitudinal axis of said ram assembly.

9. An'assembly as defined in claim 8 wherein said actuator rod and its associated plug means have a mounting aperture formed therein substantially perpendicularly of the longitudinal axis of the ram assembly.

10. An assembly as defined in claim 2 wherein said plug means are secured to their associated tubular member by an anaerobic adhesive material.

11. The method of making a hydraulic ram assembly comprising the steps of, expanding one end of a first cylindrical tubular member, securing annular fluid seal means in said one end, expanding one end of a second cylindrical tubular member having a smaller outside diameter than the inside diameter of said first tubular member and comprising the actuator rod of said assembly, securing a plug in fluid tight relation with the other end of said actuator rod, inserting said actuator rod into said first tubular member through the other end thereof with said other end of said actuator rod extending through said seal means and beyond said one end of the first tubular member, and securing a plug having an axially extending fluid supply port therein in fluid tight relation with said other end of the first tubular member, whereby fluid supplied to the interior of said first tubular member will act against the plug in the other end of said actuator rod to extend the rod while being retained in said first tubular member between said seal and said plug in the other end thereof.

12. The method as defined in claim 11 wherein said step of securing said annular fluid seal means in said first tubular member comprises the steps of machining an internal groove in said one end of said first tubular member prior to said expanding step, and after said end is expanded inserting an annular seal and an annular wiper adjacent said seal inwardly of said groove with respect to said one end of said first tubular member and inserting a snap ring in said groove to retain said seal and wiper therein.

13. The method as defined in claim 12 including the steps of inserting and securing an annular bearing in said one end of said first tubular member, after said end is expanded and prior to inserting said seal and wiper therein.

7 14. The method as defined in claim 11 including the step of inserting a bearing in said one end of said first tubular member after said one end thereof is expanded and before said sealing means is inserted therein, grinding the surface of said actuator in one pass and chrome plating the actuator prior to insertion in said first tubular member.

15. The method as defined in claim 11 wherein said plugs are secured in their respective tubular members by applying an anaerobic adhesive to said plug prior to insertion in their associated tubular members and thereafter curing said adhesive.

16. The method as defined in claim 11 including the step of drilling a mounting bore in said actuator and its associated plug substantially perpendicularly of the longitudinal axis of the assembly.

17. The method as defined in claim 11 including the step of drilling a mounting bore in said first tubular member and its associated plug substantially perpendicularly of the longitudinal axis of the assembly.

18. The method as defined in claim 17 wherein one end of said fluid supply port communicates with the interior of said first tubular member and the other end thereof is closed, said method including the steps of cross drilling said first tubular member and its associated plug to provide a bore connecting said port to the exterior of said assembly and inserting a port plug in said bore for keying said first tubular member to its associated plug and for providing a connection fitting for the fitting of a fluid supply line.

Claims

1. A hydraulic ram assembly comprising a first tubular member, plug means inserted in one end of said tubular member in fluid tight relation therewith and having a port therein providing fluid communication to the interior of the tubular member, a second tubular member defining the actuator rod of said ram and being reciprocally mounted in said first tubular member, with one end thereof adjacent said plug means and the other end thereof extending from said first tubular member, and plug means inserted in said other end of the actuator rod in fluid tight relation therewith, said first and second tubular members being generally cylindrical members, and said one end of said actuator rod being expanded to have a larger outside diameter than the remainder thereof, said outside diameter being substantially equal to the inside diameter of said first tubular member whereby said expanded one end of said actuator rod comprises guide means for the rod; the other end of said first tubular member being expanded to have a larger inside diameter than the remainder thereof, and seal means mounted in said other end of said first tubular member, said seal means including a snap ring, an annular wiper ring mounted adjacent said snap ring and inwardly thereof with respect to said other end of said first tubular member, and an annular sealing ring mounted adjacent said wiper, thereby to prevent fluid loss from said ram assembly during reciprocation of said actuator.

9. An assembly as defined in claim 8 wherein said actuator rod and its associated plug means have a mounting aperture formed therein substantially perpendicularly of the longitudinal axis of the ram assembly.

14. The method as defined in claim 11 including the step of inserting a bearing in said one end of said first tubular member after said one end thereof is expanded and before said sealing means is inserted therein, grinding the surface of said actuator in one pass and chrome plating the actuator prior to insertion in said first tubular member.