US3786669A

US3786669A - Hydraulic jointing press

Info

Publication number: US3786669A
Application number: US00254298A
Authority: US
Inventors: R Lines
Original assignee: Proline Industries Pty Ltd
Current assignee: EVANS DEAKIN INDUSTRIES Ltd CAVAN AND CHURCHILL RDS CAVAN SOUTH AUSTRALIA A CORP OF SOUTH; PROCUT PTY LTD CNR CAVAN AND CHURCHILL RDS DRY CREEK SOUTH AUSTRALIA A CORP OF SOUTH
Priority date: 1971-05-19
Filing date: 1972-05-17
Publication date: 1974-01-22
Anticipated expiration: 1991-01-22
Also published as: ZA723275B

Abstract

A hydraulic jointing press having a housing with jaws at one end thereof. The other end is expanded to house a large diameter piston to apply the jointing pressure, the large piston having a smaller piston therein to return the main piston.

Description

United States Patent [191 Lines Jan. 22, 1974 4 54] HYDRAULIC JOINTING PRESS 1,296,139 3/1919 Thompson 72/453 1 6 l 4 [75] Inventor: Raydon A. Lines, Elizabeth West, 8/196 B 72/ 53 walla FOREIGN PATENTS 0R APPLlCATlONS [73] Assign: hdush'ies 777 22s 11 1934 France 72/453 Elizabeth West, Australia 22 F! d: M 17 1972 1 e ay Primary Examiner-Richard J. Herbst PP 254,298 Attorney, Agent, or Firm-Kinzer and Dorn [30] Foreign Application Priority Data May 19, 1971 Australia PA 4935/71 [57] ABSTRACT U-S. Cl. A hydraulic jointing press having a housing with jaws lnt. at one end thereof The other end is expanded to [58] Field of Search 72/453 house a large diameter piston to apply the jointing pressure, the large piston having a smaller piston [56] References Cited therein to return the main piston.

UNITED STATES PATENTS 2,753,917 7/1956 Guthmann 1. 72/453 5 Claims, 2 Drawing Figures PAIENTED JAN 22

m4 sum

2 or 2 HYDRAULIC J OINTING PRESS This invention relates to an improved jointing press and in particular it relates to a press of the type which can be used for pressing a sleeve on to electrical lines where the wires require to be joined and where they are of a nature such, as aluminium, that soldering or similar means are not practicable.

BACKGROUND OF THE INVENTION It is customary to provide hand tools for compressing the sleeves on to wires which are to be joined, and as such tools require a very heavy force to give the necessary crimping or distortion of the sleeve to ensure an adequate hold as well as effective electrical transmission, it has been proposed heretofore to use hydraulic presses which have required very high pressure lines to be able to exert the necessary crimping force on the joining sleeves, this force required being, for instance, approximately 24,000 pounds.

To achieve forces of this magnitude in hand held tools by hydraulic means it has been necessary to use hydraulic amplifiers to bring the working pressure of the supply device to this value.

SUMMARY OF THE INVENTION It is the object of this invention to provide an improved form of device in which relatively low pressure will be able to supply the necessary pressure and this is achieved according to this invention by utilising a member which has on it one of the jaws and making the other jaw movable and guided by this member but instead of supplying hydraulic pressure in the normal manner, the device has a large area cylinder in which a piston of relatively great area is carried, hydraulic return means being provided in the piston to return the piston to'its initial position.

In this way by utilising a large piston in an expanded section of the housing and providing return means for the piston, low pressure hydraulic medium can be fed into the cylinder and because of the substantial area of the piston a sufficient force can be generated to give the necessary pressure to effectively close the sleeve on the-wires.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal cross-section view of the device along the lines l-l of FIG. 2,

FIG. 2 is an end view taken generally along the lines 2-2 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The actual device can be somewhat varied in its construction, but preferably comprises a cylindrical housing 1 which has at its operative end a portion 2 which is shaped to house the jaws 3 and 4 remote from the cylinder, the jaw 4 being fixed while jaw 3 is guided to move toward or away from fixed jaw 4 by means of a push rod 5 which terminates in one end in means whereby the jaw 3 can be locked to the push rod 5 by a pin 6. At the other end the rod 5 is attached to a piston 7 having a diameter much greater than the diameter of the housing which of course requires to be of a size such that it can conveniently be held in the hand or if this is not so then it should be provided with a piston grip or the like whereby the device can be operated.

A cylinder 8 is formed on the end of the housing I and has a diameter substantially greater than the housing diameter and preferably has a crosssectional area which is perhaps six or seven times as great as the crosssectional area of the housing so that for instance by the application of a pressure of 1,500 pounds per square inch a closing force on the jaws is exerted of perhaps 24,000 pounds.

The piston 8 is connected to the push rod 5 which actuates the movable jaw 3 and as the jaw 3 does not require to have a very great stroke, obviously the expanded end which forms the cylinder need only be of short length just sufficient to accommodate the piston and its movement.

The jaws 3 and 4 of course are preferably of a size such that they can take a series of half section members which can be slid into the jaws to be held by an appropriate inwardly projecting edge 9 and spring loaded plunger 10 so that different size members or liners can be placed into the jaws to allow the clamping of sleeves or ferrules of different size, depending of course on the dimensions of the wires being joined.

The hydraulic means for returning the piston 7 includes a further or return piston l l. The further piston 11 can conveniently comprise a smaller piston inserted into a cylinder 12 formed in the main piston 7 and the return piston 11 will suffice in that a small force only is required to return the main piston 7.

The main piston 7 is attached at one side of the piston to the push rod 5 which operates the jointing press, while the other side of the piston is formed with the cylindrical chamber 12. The return piston 11 operates in its cylindrical chamber 12 and is attached to a stationary piston rod 13 which projects through the end of the cylindrical housing 8. An annular cap 14 fits slidably on this piston rod 13 and is fitted to and is rigidly attached to the main piston 7 to close the cylindrical chamber 12, this annular cap 14 forming a continuation of the piston 7.

The stationary piston rod 13 is formed with two parallel hydraulic fluid passageways extending along its length, one of these passageways being the return passageway l5 and opening into the cylindrical chamber 12 between the return piston 11 and the cap 14 while the other passageway is the supply passageway 16 and opens into a space between the main piston 7 and the housing 8.

Hence when pressure is supplied. to the supply passage 16 fluid pressure is applied between the main piston 7 and the housing 8 to operate the press, the main piston 7 and its cylindrical chamber 12 sliding relative to the fixed return piston 11. To return the main piston 7 pressure is' applied by the return passageway 15 through the space between the return piston 11 and the cap 14 on the main piston 7. As the return piston 11 is fixed the main piston 7 is thus moved to its return position.

Suitable sealing means such as O-ring seals are provided on the pistons and between the cap and the piston rod and also between the piston rod and the opening through the housing through which the piston rod passes. The piston rod is located by any suitable means such as a circlip 17 or the like.

A control valve 18 is provided on the piston rod 13 extending through the housing 8, this valve 18 being hand operated. For convenience the control valve 18 and its operating member 19 extend at right angles to the piston rod 13 and is so mounted that the valve 18 and operating member 19 can be rotated as a unit about the axis of the piston rod 13 so that it can conveniently be operated in various awkward situations. The control valve is such that an operation of its control member 19 by the handle 20 rotatable on pin 21 mounted on support arm 22 fixed to the valve, the valve will selectively direct the fluid pressure to either the supply passage 16 or the return passage and simultaneously exhaust either the return passage 15 or the supply passage 16 so that operation of the press is achieved.

The control valve [8 includes a boss 23 surrounding the piston rod 13,

suitable passages

24, 25 being provided therein to conduct the hydraulic fluid to the hydraulic piston rod 13. The passages in the piston rod 13 terminate in

circular passageways

26, 27 spaced along the piston rod 13 so that the control valve and operating handle may rotate about the piston rod. Alternatively the piston rod 13 and the control valve 18 may be rigidly joined together, the rotation being achieved by allowing the piston rod 13 to rotate in the end of the enclosed housing 8.

The valve 18 comprises a piston member 28 having grooves and lands to direct the fluid from inlet passage 24 to either passage 25 or 25a and to exhaust from passages 25a and 25 as desired, through exhaust passages not shown to an exhaust line. The control valve is conventional and need not be described in detail.

Referring to FIG. 2 the piston member is biased into its central position by a coil spring 29, the spring acting between

washers

30 and 31. A stud 32 having a shoulder 33 is attached to the end of the piston 28, the

' washer 30 bearing against the head of the stud 32 and against shoulder 34 on cap 35, while the washer 31 bears on the end of the piston 28 and also against the valve housing at 36.

ln this condition the valve piston is centralised. By moving the valve downwardly the piston 28 moves washer 31 against the spring 29, the washer 30 bearing against shoulder 34 so that the spring 29 applies a restoring force on the piston 28. Similarly if the piston is moved upwardly the head of stud 32 moves washer 30 to compress the spring 29 against washer 31 which bears on the shoulder 36.

From the foregoing it will be realised that because of the provisions of an expanded end on the housing which can take the relatively large piston in the cylinder formed in the housing, a unit is provided which does not require a power amplifier and then simply comprises a movable member which has at its one end the movable jaw and at its other end the piston the piston being returned hydraulically by a further piston thus ensuring a light weight structure which can easily be handled and which operates on a relatively low hydraulic pressure.

I claim:

1. A portable, hand-held hydraulic jointing press comprising a stationary jaw and a movable jaw, a push rod connected to the movable jaw, a cylinder-like housing surrounding the push rod, said housing having an enlarged cylindrical portion closed at one end and constituting a main cylinder of cross-sectional area at least several multiples of the remaining cross-sectional area of said housing, a main piston mounted in said main cylinder, said main piston having a cylinder of smaller diameter and being connected to the push rod so the fluid under pressure supplied to the main cylinder will advance the push rod to close the jaws, the smaller cylinder having a return piston mounted therein, means closing one end of the smaller cylinder to define a return cylinder for the return piston, and means to selectively direct fluid under pressure to the main cylinder or return cylinder.

2. A hydraulic jointing press as defined in claim 1 wherein the return piston is stationary and has a piston rod extending through a cap forming the means closing the end of the return cylinder, the piston rod having a pair of longitudinal passages for operating fluid therein, one opening into the main cylinder and the other into the cylindrical portion of the return cylinder between the return piston and the cap.

3. A hydraulic jointing press as defined in claim 2 wherein the means to selectively direct fluid pressure includes a control valve mounted on the end of the stationary piston rod, the control valve being operated by a linkage connected to a handle by which the control valve is operated and the jointing presses manipulated, the control valve being connected to the piston rod whereby the control valve, piston rod and return piston are rotatable relative to the-main piston.

4. A hydraulic jointing press as defined in claim 2 wherein the means to selectively direct fluid pressure includes a control valve rotatably mounted on the piston rod, the longitudinal passages in the piston rod opening into circumferential grooves on the piston rod, the control valve having passages connecting to the grooves and having an operating handle whereby the control valve and operating handle are rotatable relative to the piston rod.

5. A hydraulic jointing press as defined in claim 2 wherein the means to selectively direct fluid pressure includes a control valve housing and a valve piston, the valve piston having lands and grooves to selectively direct fluid pressure from an inlet to the cylinder of the main or return piston and to exhaust the other cylinder, the valve piston being biased into its central position by a spring acting between spaced washers each adapted to bear on a portion of the valve piston and the valve housing.

Claims

3. A hydraulic jointing press as defined in claim 2 wherein the means to selectively direct fluid pressure includes a control valve mounted on the end of the stationary piston rod, the control valve being operated by a linkage connected to a handle by which the control valve is operated and the jointing presses manipulated, the control valve being connected to the piston rod whereby the control valve, piston rod and return piston are rotatable relative to the main piston.