US3485141A

US3485141A - Multipiston pressure cylinder for tools

Info

Publication number: US3485141A
Application number: US663669A
Authority: US
Inventors: Norman C Ott; Douglas Arnold
Original assignee: Sargent and Co
Current assignee: ROSTRA TOOL COMPANY A CORP OF CT
Priority date: 1967-08-28
Filing date: 1967-08-28
Publication date: 1969-12-23
Anticipated expiration: 1986-12-23

Description

Dec. 23, 1969 c, QTT ET AL 3,485,141

MULTIPISTON PRESSURE CYLINDER FOR TOOLS Filed Aug. 28, 1967 2 Sheets-Sheet 1 1,2, INVENTORS 50 g u Ncwmom C. 0+:

39 5 58 G BY Douqkxs Fhnokd 40 92.21 m 1M9 WSHF mgxzggb Dec. 23, 1969 N. c. on" ET AL 3,485,141

MULTIPISTON PRESSURE CYLINDER FOR TOOLS Filed Aug. 28, 1967 E Sheets-Sheet 2 Novman (1.01% Doucflqs Fh'noki DATKD OMQ ATT RNEYSi United States Patent MULTIPISTON PRESSURE CYLINDER FOR TOOLS Norman C. Ott, Clinton, and Douglas Arnold, Meriden,

Conn., assignors to Sargent & Company, New Haven,

Conn., a corporation of Delaware Filed Aug. 28, 1967, Ser. No. 663,669 Int. Cl. F1511 11/08, 13/042; F01]: 7/16 US. Cl. 91--411 Claims ABSTRACT OF THE DISCLOSURE A fluid cylinder, comprising sleeve means, a piston pilot tube, a plurality of pistons positioned about said tube and spaced apart from each other, said tube and said pistons mounted to move in unison within said sleeve means, a plurality of piston battle means positioned be tween the interior of said sleeve means and the outside surface of said tube, one each of said baffle means positioned between some of said pistons, and fluid inlet means for permitting fluid to enter between some of said pistons and bafile means.

This invention relates to a multi-stage stack construction fluid cylinder and more particularly to a high power air cylinder construction. The air cylinder of this invention is particularly suitable for use in conjunction with hand tools and the like which require a supplemental source of power to operate mechanical parts thereof. The use of an air cylinder for a hand tool is shown in U.S. Patent 3,012,321.

The air cylinder of this invention may be used with cable cutters or wire strippers, clamping mechanisms, etc. The construction disclosed in this invention is unique in that, by lengthening or shortening some of the parts and adding or subtracting some of the parts of the air cylinder, it is possible to increase or decrease the power output without having to redesign the entire cylinder structure. The multi-stage or tandem air cylinder or this invention is composed of two or more sections or stages, assembled one behind the other so that the portions of each section are connected and operate in unison.

In the preferred form of construction of this unit, the pistons of this invention are assembled over a piston pilot tube, such that the tube ensures perfect alignment between pistons, their respective chambers and the cylinder sleeve means. In this construction, long term, trouble-free operation is attainable without significant power loss over long periods of time.

As one of its objects, the present invention provides a novel, high power fluid cylinder having a multistage stack construction, wherein each stage is substantially identical.

Another object of this invention is to provide a new and improved air cylinder having a multi-stage stack construction wherein only certain parts of the cylinder construction need be lengthened or shortened, or certain parts added or subtracted, to increase or decrease the power output when the number of identical chambers is increased or decreased.

A further object of this invention is to provide a new and improved high power air cylinder construction, wherein the pistons are assembled over the piston pilot tube, said tube being cross drilled to allow the passage of air into each section or stage.

Still other objects and advantages of this invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the apparatus embodying the features of construction, combinations and arrangements of parts, all as exemplified in the detailed disclosure hereinafter set forth and the scope of the invention will be indicated in the claims.

3,485,141 Patented Dec. 23, 1969 For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in conjunction with the accompanying drawings, in which FIG. 1 is an end view of the fluid cylinder according to this invention,

FIG. 2 is an opposite end view of the fluid cylinder of this invention;

FIG. 3 is a sectional view taken along line 33 of FIG. 1, showing the parts of the cylinder positioned under fluid pressure;

FIG. 4 is a view similar to FIG. 3, showing the position of parts of the fluid cylinder of this invention in their neutral, at rest position;

FIG. 5 is a sectional view similar to FIG. 3, showing an alternate embodiment of a fluid cylinder according to this invention;

FIG. 6 is a sectional view taken along line 66 of of FIG. 5; and

FIG. 7 is a view similar to FIG. 3, showing another embodiment of a fluid cylinder according to this invention.

Referring to FIGS. l-4, there is shown the preferred embodiment of the air cylinder of this invention. The air cylinder comprises a plurality of cylinder sleeves shown at 10 and a plurality of battles shown at 11. Positioned within the sleeves 10 is a plurality of pistons 12 which are mounted about a piston pilot tube 13 and held in position at one end by a lock nut 15 and at the other end by a threaded ram 16 coupled to the tube 13. At one end of the air cylinder there is provided a member 20 having a passage 21 which opens into a larger passage shown at 22. Positioned about the sleeves 10 is another sleeve member 24, over which is position an end cap 25 for holding member 20 in place. At the other end of the cylinder there is provided an end member 30, in which are positioned return springs shown at 31 in a cut-out thereof, the springs 31 engaging one of the pistons 12. The springs 31 are utilized to initially set the position of the ram and pistons as well as the pilot tube within the sleeve 10. The member is held in place by an end cap 35 which threadedly engages the outer sleeve member 24. Also positioned at this end is a jaw mounting head 37 for supporting a tool to be used in conjunction with the air cylinder.

As part of the improved construction of the preferred embodiment of the invention shown in FIG. 3, the end member 20 also has a portion thereof which includes a bore 38 in which is positioned a valve plunger 39. The plunger 39 is operated by a resilient valve lever shown at 40 which is coupled to the end cap 35 by means of a cap screw shown at 45. The plunger 39 is resiliently biased by a valve return spring 46 and is formed with a circumferential reduced portion shown at 47 which cooperates with an inlet for fluid shown at 48 in the member 20 for permitting air or fluid to flow into the passage 21 and thence into passage 22 to the interior of the cylinder. In order to guide the plunger 39, a set screw 50 is provided which rides within a portion 51 of the plunger 39. Openings 52 are provided in the pilot tube 13 to provide air between the battles and the cylinders. The openings 52 cooperate with openings 53 formed in a portion of the pistons 12. A fluid, such as air, is thereby provided to the bore 48, permitted to pass by depression of the plunger 39 through into bore 21 and thence through bore 22 into a cavity 54 to cause the first of the pistons to move to the right of FIG. 3. The air also circulates and enters the cavities between the next piston and baflle. In this manner, the air enters between each of the pistons and a rear baflle portion to cause the ram 16 to move to the right of FIG. 3. At the same time, air is exhausted from the other side of the piston by openings shown at 58 formed in the bafiles 11 and from an opening 59 in the end member 30. To permit the air to be expelled from the exhaust 58, there are provided cooperating exhaust openings shown at in the outer sleeve 24, thus permitting the air to enter the atmosphere.

- As shown in FIG. 4, the plunger is in its released position, so that air is no longer permitted entry to the cylinder from the bore 48. Fluid, such as hydraulic fluid or air, may be provided by a conventional means.

Referring now to FIGS. 5 and 6, there is shown an alternate embodiment of this invention. In this embodiment, instead of each of the exhaust means permitting air to flow directly to the atmosphere, exhaust means shown at and 66 are provided and are coupled to channels or slots shown at 69 formed in the outer sleeve of the cylinder 70. Additionally, the springs of the preferred embodiment of this invention are removed, and a fluid or air passage 71 is provided, coupled to the slot 69. The purpose of these slots or exhaust means 69 is to permit air to enter between the pistons and the baflies, to cause the return of the pistons to an initial starting position, rather than use the springs of the preferred embodiment, to accomplish the same result. The exhaust means 69 extends into the end member 72, thence into a bore '73 formed in the end member. In the alternate embodiment of FIGS. 5 and 6, the plunger 74 is constructed slightly differently, such that it has one additional reduced portion 75 as well as the reduced portion 76.

As shown in FIGS. 5 and 6, air or hydraulic fluid may enter the bore 77 and flow into the reduced diameter portion 76 to cause the ram 78 of the cylinder to move to the right. While this is occurring, the air or fluid is being exhausted through the slots 69 in the bore 73 and through the second reduced diameter portion 75 to a bore 79. In order to cause the ram 78 to move to the left, the plunger is released and the air or fluid will enter from the bore 77, through the reduced diameter portion 76 and through the bore 73, thence through the slots 69 and finally through the exhaust means 66 and 65. At the same time, air is being exhausted through the bore 80 and then through a portion of the cavity 81 housing the spring return by way of an exhaust bore shown at 82. In this manner, ram 78 may be caused to move to the right or left of FIG. 5 by the passage of fluid through the appropriate channels, providing fluid or air between the baflles and pistons.

Referring now to FIG. 7, there is shown another embodiment of the invention. In this embodiment, the outer cylinder is made up of a plurality of outer sleeve sections coupled to each other by threaded portions. The sections 90 are formed such that baflle means 91 may be spaced along the inner circumference of the sections and retained in position. The piston pilot tube of this embodiment also comprises a plurality of sections 92 which are screwed together to retain in position a plurality of pistons 93. The exhaust and inlet means of FIGS. 1-4 are also provided in this embodiment. A ram shown at 92a is coupled to the end of the pilot tube and is slidably supported within an end member 94 housing spring return members 95 which engage one of the pistons 93. An end cap member 97 is provided to retain end member 98.

What is claimed is:

1. A multipiston pressure cylinder which is powered in one direction by fluid pressure and is used for driving tools, comprising in combination, sleeve means, first and second wall means enclosing both ends of said sleeve means, a hollow piston tube, a plurality of pistons having front and rear faces, mounted on said piston tube such that said tube and said pistons are slidably movable in unison within said sleeve means, a plurality of baflle means permanently mounted within said sleeve means such that there is a bafile means between every two pistons to form a plurality of piston chambers, first fluid inlet means formed in said hollow tube for admitting pressurized fluid to said chambers at the front faces of said pistons, exhaust means formed in said sleeve means and in a portion of said baffle means to expose the rear faces of said pistons to atmospheric pressure, and spring means for biasing said pistons to cause them to return to their original positions upon the release of fluid pressure; characterized in the improvement in that valve means are mounted in said first wall means for permitting fluid pressure to be applied simultaneously to the front face of each piston, and in that said spring means are mounted in said second wall means to act upon the rear face of the piston adjacent said second wall means.

2. A multipiston pressure cylinder in accordance with claim 1, wherein said spring means comprises two springs positioned in two bores in said second wall means on opposite sides of said hollow piston tube to bias the piston adjacent said second wall means.

3. A multipiston pressure cylinder in accordance with claim 2, wherein said first wall means has first and second channels for the passage of pressurized fluid therein, and wherein said valve means comprises a cylindrical member slidably mounted in a bore in said first wall means and positioned between said first and second channels and having a first annular cut-away section to permit pressurized fluid to pass through said cut-away section, said first and second channels and into the interior of said sleeve means to actuate all of the pistons simultaneously.

4. A multipiston pressure cylinder in accordance with claim 3, wherein said cylindrical member is spring-biased in said bore and is retained in said bore by a pin located in said first wall means, which 'pin engages a second annular cut-away section on said cylindrical member such that when said cylindrical member is in an equilibrium position the passage of fluid between said first and second channels is prevented and said first cut-away section is positioned to allow fluid to pass from said sleeve means through said second channel and a third channel located in said first wall means.

5. A multipiston pressure cylinder in accordance with claim 4, wherein said pistons have longitudinally-extending tubular sections which fit over said'hollow piston tube for mounting said pistons in permanent fixed relationship to each other, and wherein second fluid inlet means are located in said tubular sections adjacent said first fluid inlet means for admitting pressurized fluid to said piston chambers at the front faces of said pistons.

References Cited UNITED STATES PATENTS 825,866 7/ 1906 Rogers. 1,565,767 12/ 1925 Westbrook. 2,354,841 8/ 1944 Shaff. 2,126,605 12/ 1955 Tebbetts. 3,274,903 9/ 1966 Fischer et a1. 9l469 PAUL E. MASLOUSKY, Primary Examiner US. Cl. X.R.