US3608438A

US3608438A - Rectangular body ram

Info

Publication number: US3608438A
Application number: US728859A
Authority: US
Inventors: Vitas T Thomas; Robert A Lovdahl
Original assignee: Tomco Inc
Current assignee: Tomco Inc
Priority date: 1968-05-13
Filing date: 1968-05-13
Publication date: 1971-09-28
Anticipated expiration: 1988-09-28

Abstract

DISCLOSED HEREIN IS A WORK HOLDING ASSEMBLY INCLUDING A HYDRAULIC DEVICE HAVING A SOLID OR HOLLOW RAM MOUNTED FOR RECIPROCAL MOTION WITH N A RECTANGULAR HOUSING WITH A PISTON HEAD ON SAID RAM POSITIONED IN SEALING ENGAGEMENT WITH A BORE IN THE HOUSING. FLUID FLOW PASSAGES IN THE WALLS OF THE HOUSING ENTER THE BORE AT POINTS OUT OF THE PATH OF MOTION OF SAID PISTON HEAD AND A MOUNTING SURFACE IS PROVIDED ON THE HOUSING IN A PLANE PERPENDICULAR TO THE AXIS OF THE RAM.

Description

Sept. 28, 1971 v. T. THOMAS ErAL 3,608,438

RECTANGULAR BODY RAM Filed May 15, 1968 B MIEI, klaag/Jeun#- @Zwin/wm?,

ATTO NEYS United States Patent O1 3,608,438 Patented Sept. 28, 1971 hcc 3,608,438 RECTANGULAR BODY RAM Vitas T. Thomas and Robert A. Lovdahl, Racine, Wis., assgnors to Tomco, Inc., Racine, Wis. Filed May 13, 1968, Ser. No. 728,859 The portion of the term of the patent subsequent to May 12. 1987, has been disclaimed Int. Cl. F01b 31/00 U.S. Cl. 92-163 8 Claims ABSTRACT OF THE DISCLOSURE Disclosed herein is a work holding assembly including a hydraulic device having a solid or hollow ram mounted for reciprocal motion within a rectangular housing with a piston head on said ram positioned in sealing engagement with a bore in the housing. Fluid flow passages in the walls of the housing enter the bore at points out of the path of motion of said piston head and a mounting surface is provided on the housing in a plane perpendicular to the axis of the ram.

BACKGROUND OF THE INVENTION This invention relates to a work holding assembly of the type which is mounted on machine tools to hold Work pieces of various shapes. These assemblies are usually specially designed for particular types of products and are often connected to the work piece from a point beneath the work table.

SUMMARY OF THE INVENTION The work holding y'assembly yaccording to this invention includes a hydraulic device of compact design which can be mounted on `any plane of work surface of a machine by a simple mounting arrangement. More particularly, the work holding assembly includes a hydraulic device having either a solid or hollow ram having a piston head mounted for reciprocal motion within a rectangular housing having a mounting surface perpendicular to the direction of motion of the ram. The ram may be either single acting or double acting with the fluid flow passages to actuate the ram entering the bore at points remote from the path of motion of the piston head. The ram can be actuated by air, oil or both, and if single acting, a spring can be used for return motion. If a hollow ram is used, the hydraulic device can be secured through the work piece to the top of the work surface on the machine.

Other objects and advantages will become apparent from the following `detailed description when read in connection with the accompanying drawings in which:

FIG. 1 is a perspective view of a rectangular hydraulic device for a work holding assembly.

FIG. 2 is a section view in elevation of a hydraulic device having a hollow ram.

FIG. 3 is a top view of the hydraulic device of FIG. 2.

FIG. 4 is a side view in elevation of an alternate form of the hydraulic device.

FIG. 5 is a top View of the alternate form of the hydraulic device shown in FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. The scope of the invention is defined in the claims appended hereto.

Referring to FIGS. 1 through 3 of the drawing, one form of the hydraulic device according to the invention is shown which includes a rectangular housing having a ram 12 mounted for reciprocal motion in the housing with an end cap 14 to retain the ram within the housing. The lower or bottom surface 16 of the housing is flat forming a mounting surface which can be secured to a working surface by means of mounting bolts 15 which are inserted in mounting holes 17 provided in the housing. Hydraulic fluid from a pressure source (not shown) is supplied to the hydraulic device through

pressure lines

18 and 20 connected to

fluid passages

22 and 24 in the side wall 26 of the housing.

More specifically, the housing includes a first bore 28 extending part way through the housing and a second bore 30 coaxial with the first bore 28 and of smaller diameter extending through the remainder of the housing. A threaded section 32 is provided at the inlet to the first bore 28 with a chamfer or tapered section 34 provided between the threaded section 32 and the first bore 28. An annular shoulder 36 is provided on the end wall 38 of the first bore 28. The first fluid flow passage 22 extends through the side wall 26 and into the bore 28 through the tapered section 34. The second passage 24 extends through the side wall 26 and enters bore 28 through the annular shoulder 36.

The ram 12 comprises a hollow tubular member having a central passage 40 and includes a piston head 42 which is positioned in the first bore 28 in the housing and is seated on shoulder 36 leaving a space 44 between the piston head `42 and the wall 38 of the housing. The lower section 46 of the ram 12 is axially aligned in the second bore 30 with the end 48 of the ram flush with the lower or mounting surface 16 of the housing when the piston head rests on the shoulder 36. The upper section 50 of the ram 12 extends upward through the threaded section 32 outwardly beyond the upper surface 52 of the housing.

The cap can be shaped in various ways with a cylindrical cap 14 shown in FIGS. 1 through 3. The retainer cap 14 has a threaded section 54 which is screwed into the threaded section 32 of the housing with the ram axially aligned in aperture 56 in the cap. The inner end 58 of the cap terminates short of the tapered section 34 in the housing leaving an annular gap between the upper end of the bore 28 and the end 58 of the cap. A ram wiper 62 is provided in a recess 64 in the end of the cap 14 to wipe the surface of the ram when it is retracted into the housing to prevent contamination of the hydraulic fluid within the housing. The ram wiper `62, as seen in FIG. 2 of the drawing, has a V-shape to wipe the surface of the ram as it is retracted.

Various seal means are used to seal the ram 12 in the housing 10 vand cap 14. An O-ring 66 is provided between the cap 14 and the housing to seal the bore 28. A T-shaped seal having back-up rings 72 on each side is provided in a groove 74 in the second bore 30 and is positioned to `sealingly engage the outer surface of the lower section 46 of the ram. A piston head seal 76 is provided in a groove 78 in the piston head with backup rings v80 provided on each side of the seal. The backup rings for both seals are made of a plastic material such as Teflon (tetrafluoroethylene) and prevent extrusion of the seals. The O-ring 66 and the

seals

70 and 76 are made of a resilient material such as rubber or neoprene.

The ram can be operated either as a double acting ram or single acting ram with air or oil as the hydraulic fluid. A spring 60 may be positioned between the piston head and end cap to retract the ram in a single acting device. The hydraulic fluid is admitted through passage 24 into the space 44 provided between the piston head 42 and the end wall 38 of the first bore 28. An unobstructed flow path is thereby provided to the piston head. When the piston head moves to the other end of the bore 28, it

will be stopped by the end 58 of the end cap 14. The lower section 46 of the ram is long enough to remain 1n contact with the seal 72 when the piston head engages the end 58 of the end cap. Return fluid admitted through passage 22 will enter the annular gap between the end cap 14 and the top of the bore 28 to retract the ram into the housing. The return spring 60 will initiate the return motion of the ram when pressure is relieved in the space 44.

The alternate form of the hydraulic device, shown in FIGS. 4 and 5 includes a rectangular housing 100 having a ram 102 mounted for reciprocal motion within the housing with an end cap 104 retaining the ram 102 in the housing. The lower or mounting surface 106 of the housing is flat and lies in a plane perpendicular to the path of motion of the ram for mounting on any planar ,surface by means of mounting bolts (not shown) passing through the mounting holes 108 in the housing. Hydraulic fluid from a pressure source (not shown) is supplied to the housing through

pressure lines

18 and 20 connected to the

fluid passages

114 and 116 in the side wall 118 of the housing.

The housing in this embodiment of the invention, includes a first bore 120 terminating at an end wall 122 with a threaded section 124 of a larger diameter provided at the inlet to the bore 120. A tapered section 126 is provided between the threaded section 124 and the bore 120.

The ram 102 is a solid ram having a piston head 128 positioned for reciprocal motion in the first bore 120. A button 130 on the piston head 128 is positioned to engage end wall 122 to provide a space 132 for the admission of fluid through passage 116.

The retainer cap 104 in this embodiment is in the form of a hexagonal nut and includes a threaded section 134 which is screwed into the threaded section 124 in the housing with the end 136 of the cap spaced from the tapered section 126. An aperture 138 is provided in the cap through which the ram 102 extends. A return spring 140 is positioned between the piston head 128 and the end 136 of the cap 102.

Various seal means are provided to seal the ram 102 in the bore 120 of the housing. An O-ring 142 is positioned between the cap and the housing and an O-ring 144 is positioned in a groove 145 in the cap for sealing engagement with the ram. A ram wiper 146 is positioned in a recess 148 at the end of the cap 104 to wipe the ram as it is retracted into the bore of the housing. The piston head 128 is sealed by an O-ring 150 and a backup ring 152 positioned in an annular groove 154 in the piston head to sealngly engage the bore 120.

The ram can be actuated either by air or hydraulic fluid and may be double acting or single acting. Hydraulic fluid under pressure is forced into the space 132 between the piston head 128 and end wall 122 to force the ram outward from the housing. When the pressure is released on the fluid in space 132, the spring 140 will initiate the return motion of the ram. Air or hydraulic fluid forced through passage 114 will enter the annular gap between the end cap and tapered section to increase the speed of the return movement of the ram. The body may have configuration other than that illustrated.

What is claimed is:

1. A hydraulic device comprising a rectangular housing having a first bore terminating at an end wall and a second bore having a larger diameter than said first bore, a threaded section at the open end of said second bore, a tapered section connecting said first bore to said second bore, a first fluid flow passage connected to said first bore through said housing, a second fluid flow passage connected to said tapered section through said housing, an

end cap in said threaded section having an aperture coaxial with said first bore, said end cap being spaced from said tapered section, said space providing fluid communication between said second flow passage and said bore, and a ram having a piston head mounted for reciprocal motion between said first and second passages in said first bore, said ram extending outwardly through said aperture in said end cap.

2. A device according to claim 1 including means to define a space between said piston head and said housing in communication with said first passage.

3. A device according to claim 1 wherein said housing includes a mounting surface located in a plane perpendicular to the axis of said ram.

4. A device according to claim 1 including a V-shaped ram wiper in said end cap positioned to slideably engage said ram.

5. The hydraulic device according to claim 2 wherein said defining means comprises a button on said ram positioned to engage said end wall.

6. A hydraulic device comprising a rectangular housing having end walls, a mounting surface on one of said end walls, a first bore terminating at the other of said end walls, a second bore having a larger diameter than said first bore, a threaded section at the open end4 of said second bore, a tapered section connecting said first bore to said second bore, a third bore originating at said mounting surface in said one of said end walls and extending through said end wall in a coaxial relation with said first bore, a first fluid flow passage connected to said rst bore through said housing, a second fluid flow passage connected to said tapered section through said housing, an end cap in said threaded section having an aperture coaxial with said first bore, said end cap being spaced from said tapered section, said space providing fluid communication between said second flow passage and said bore, and a ram having a piston head mounted for reciprocal motion between said first and second passages in said first bore, said ram extending outwardly through said aperture in said end cap and including a section extending through said third bore and terminating flush with said mounting surface when said piston head is positioned next to said first fluid passage.

7. A device according to claim 6 wherein said ram comprises a hollow tubular member to accommodate a workpiece.

8. A device according to claim 6 including an annular shoulder spaced from said end wall to define a space between said piston head and said end wall, said first fluid flow passage entering said first bore through said shoulder.

References Cited UNITED STATES PATENTS 2,171,240 8/ 1939 Hinsch 92-163X 2,451,089 10/ 1948 Hunter 92-169X 2,628,608 2/ 1953 LoeCy, Ir. 92-33X 2,960,077 11/1960 Bosi 92-168X 3,005,669 10/ 1961 Nunnemacher 92--161 3,03 8,448 6/ 1962 Corwin 92-161 3,138,073 6/1964 Whitehouse 92-165X 3,313,215 4/1967 Bieri 92-165X 3,395,620 8/ 1968 Schmoeger 92-161 MARTIN P. SCHWADRON, Primary Examiner L. J. PAYNE, Assistant Examiner U.S. Cl. X.R. 92-165