AU463552B2 - Hydraulic jointing press - Google Patents

Description

4 2, 3 05 72 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 transmissioh, 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 fixed jaw and a movable jaw, but instead

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42,3 05 p2 normal manner, of supplying hydraulic pressure in the in which a piston the device has a large area cylinder return arelatively great area is carried, hydraulic return the piston means being provided in the piston to to its initial position. in an In this way by.utilising a large piston and providing return expanded section of the housing hydraulic medium can means for the piston, low pressure of the substantial be fed into the cylinder'and because can be generated area of the piston a sufficient force effectively close to give the necessary pressure to the sleeve on the wires. BRIEF DESCRIPTION OF THE DRAWINGS view of Fig. 1 is a longitudinal cross-sectional the device along the lines 1-1 of Fig. 2, along the Fig. 2 is an end view taken generally lines 2-2 of Fig. 1. DESCRIPTION OF THE PREFERRED EMBODIMENT varied in its The actual device can be somewhat a cylindrical construction, but preferably comprises a portion 2 housing 1 which has at its operative end 4 remote from the which is shaped to house the jaws 3 and jaw 3 is guided to move cylinder, the jaw 4 being fixed while of a push rod toward or away from fixed jaw 4 by means the jaw 3 can which terminates in one end in means whereby 6. At the other end be locked to the push rod 5 by a pin a diameter much the rod 5 is attached to a piston 7 having greater than the greater atat least several multiples

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42,305171 of course requires to diameter of the housing which be held be of a size such that it can conveniently then it should be in the hand or if this is not so like whereby the provided with a piston grip or the

device can be operated. of the housing 1 A cylinder 8 is formed on the end greater than the and has a diameter substantially a cross-sectional housing diameter and preferably has times as great area which is perhaps six or seven housing so that as the cross-sectional area of the of a pressure of 1500 for instance by the application force on the jaws pounds per square inch a closing

is exerted of perhaps 24,000 pounds.

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

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

being joined.

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42,305 r/ The hydraulic means for returning the piston 7

includes a further or return piston 11. The further

smaller piston piston 11 can conveniently comprise a piston inserted into a cylinder 12 formed in the main a 7 and the return piston 11 will suffice in that main piston 7. small force only is required to return the of the The main piston 7 is attached at one side jointing piston to the push rod 5 which operates the is formed press, while the other side of the piston with the cylindrical chamber 12. The return piston

12 and is 11 operates in its cylindrical chamber attached to a stationary piston rod 13 which projects

through the end of the cylindrical housing 8. An 13 and annular cap 14 fits slidably on this piston rod

is fitted to and is rigidly attached to the main this piston 7 to close the cylindrical chamber 12, piston 7. 'annular cap 14 forming a continuation of the

The stationary piston rod 13 is formed with two along parallel hydraulic fluid passageways extending return its length, one of these passageways being the chamber passageway 15 and opening into the cylindrical 12 between the return piston 11 and the cap 14 while and the other passageway is the supply passageway 16 7 and opens into a space between the main piston the housing 8.

Hence when pressure is supplied to the supply the main passage 16 fluid pressure is applied.between the piston 7 and the housing 8 to operate the press,

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42,305 n chamber 12 main piston 7 and its cylindrical piston 11. sliding relative to the fixed return is applied To return the main piston 7 pressure the space by the return passageway 15 through the cap 14 on between the return piston 11 and piston 11 is fixed the main piston 7. As the return its return the main piston 7 is thus moved to

position. seals are Suitable sealing means such as o-ring the cap and the provided on the pistons and between rod and the piston rod and also between the piston which the piston opening through the housing through by any suitable rod passes. The piston rod is located like. means such as a circlip 17 or the A control valve 18 is provided on the piston rod valve 18 being 13 extending through the housing 8, this valve 18 hand operated. For convenience the control right angles and its operating member 19 extend at that the valve to the piston rod 13 and is so mounted as a unit 18 and operating member 19 can be rotated that it can about the axis of the piston rod 13 so situations. conveniently be operated in various awkward of its The control valve is such that an operation on pin 21 control member 19 by the handle 20 rotatable valve, the valve mounted on support arm 22 fixed to the to either will selectively direct the fluid pressure 15 and the supply passage 16 or the return passage passage simultaneously exhaust either the return

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42,305/i or the supply passage 16 so that operation of the

press is achieved.

The control valve 18 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 abo.ut 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

while the washer 31 bears on the end of the piston

28 and also against the valve housing at 36.

In this condition the valve piston is centralised.

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42 3 05 n 28 moves By moving the valve downwardly the piston washer 31 against the spring 29, the washer 30 bearing a against shoulder 34 so that the spring 29 applies the restoring force on the piston 28. Similarly if 32 moves piston is moved upwardly the head of stud 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 and provided which does not require a power amplifier 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.

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Claims (3)

42,3057 The claims defining the invention are as follows:-

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 carrying the stationary jaw and 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 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.

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42, 3 05p17 3. A hydraulic jointing.press as defined in fluid claim 2 wherein the means to selectively direct the pressure includes a control valve mounted on

stationary piston rod, the control valve being operated control by a linkage connected to a handle by which the

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.

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

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42,305 rn each adapted to bear on a portion of the valve piston

and the valve housing.

6. A hydraulic jointing press substantially as

hereinbefore described with reference to and as shown

in the accompanying drawings.

Dated this 30th day of June, 1975.

PROLINE INDUSTRIES PTY. LTD., By.their Patent Attorneys, COLLISON CO.

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