GB2130513A

GB2130513A - Hydraulic wrench with counteracting roller

Info

Publication number: GB2130513A
Application number: GB8325694A
Authority: GB
Inventors: John K Junkers
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-09-27
Filing date: 1983-09-26
Publication date: 1984-06-06
Also published as: DE3334618A1; DE8327478U1; FR2533486A1; GB8325694D0

Abstract

A hydraulic wrench for tightening or loosening threaded connectors (25) connecting a flange (F) to a member, comprises a support means (1) pivotally mounting on its upper portion (1a) a hydraulic cylinder (6) about a pivot axis (8) transverse to the axis of the cylinder. A piston (9) reciprocatable in the cylinder has a piston rod (10) projecting with its free end (10A) beyond the cylinder. The lower portion (1b) of the support means 1, pivotally supports a lever arrangement (11) about a second pivot axis (12) substantially parallel and forwardly of the first pivot axis. The lever arrangement (11) is pivotally connected at one end (14) to the free end of the piston rod and is provided adjacent to its other end with an opening (24) for receiving the head of the threaded connector (25) to be turned, whereby during turning of the head (25) in the direction of the arrow a a force is created tending to turn the support means (1) about the second pivot axis (12) in the opposite direction. The lower portion (1b) of the support means (1) supports at least one roller (27) adapted to rollingly engage the periphery (29) of the flange (F) for counter-acting the tightening force. <IMAGE>

Description

SPECIFICATION Hydraulic wrench with counteracting roller The present invention relates to a hydraulic wrench for tightening or loosening threaded connectors connecting a flange to a member or two flanges to each other. More specifically, the present invention relates to a hydraulic wrench in which the head of the threaded connector which has to be tightened or loosened by the wrench is located in a space which is rather limited about the axis of the threaded connector and above the head to be tightened or loosened thereon. Such wrenches are for instance disclosed in US Patents Nos. 4,079,641 and 4,336,727.

During tightening or loosening a threaded connector in one direction, a reaction force is created which tends to turn the whole wrench in the opposite direction. To take up this reaction force, the wrenches as disclosed in the aforementioned patents are provided with means for slidingly engaging a stationary member adjacent to the connector to be turned, which is usually another connector adjacent to that being turned by the wrench.

One disadvantage of these known constructions is that the counteracting means, usually in the form of a plate connected to the wrench support, slidingly engages the stationary member with tremendous force, creating thereby considerable friction which reduces the efficiency of the arrangement.

The present invention therefore seeks to provide a hydraulic wrench which can be applied to a threaded connector to tighten or loosen the same in which the space about the exposed connector and above the same is rather limited and which overcomes the aforementioned shortcomings of hydraulic wrenches of the aforementioned kind known in the art.

Preferred embodiments of wrench in accordance with the present invention are extremely simple and compact in their construction so that they may be manufactured at reasonable cost, stand up perfectly under extended use and can be handled with relative ease.

According to the present invention there is provided a hydraulic wrench for tightening or loosening threaded connectors connecting a flange to a member which wrench comprises support means having a first portion and a second portion integral with the first portion, hydraulic operating means comprising a cylinder having an axis and being connected to the first portion of the support means, a piston axially reciprocatable in said cylinder and a piston rod connected at one end to the piston and having an opposite free end, lever means connected intermediate its ends to the second portion of said support means pivotable about a pivot axis transverse to said cylinder axis, said lever means being pivotally connected at one end to said free end of the piston rod and being provided in the region of its other end with means for engaging a threaded connector to be turned, whereby during such turning of a threaded connector in one direction a force is created tending to turn said support means in the opposite direction about said pivot axis, and at least one roller mounted on the second portion of the support means rearwardly of said pivot axis and spaced in the direction of the latter from said lever means said roller being turnable about an axis substantially parallel to said pivot axis and being adapted to roll along the periphery of the flange for counteracting said force.

In this construction the sliding friction created by the counteracting means according to the prior art is replaced by the rolling friction of the counteracting roller engaging the peripheral surface of the flange, whereby the efficiency of the wrench is considerably increased. An additionai advantage of this construction is that it can be used regardless of the spacings of the connectors (e.g. nuts) to be tightened from each other, since the counteracting means does not require a fixed object adjacent to the connector to be tightened since the counteracting means in the form of a roller will roll along the peripheral surface of the flange on which the connectors to be tightened are arranged.

Preferably the cylinder is pivotable about a first pivot axis transverse to said cylinder axis and the lever means is pivotable about a second pivot axis substantially parallel to said first pivot axis. Suitably the cylinder is mounted in the region of its front end, that is the end beyond which the piston rod projects on the support pivotable about the abovementioned first pivot axis.

Preferably the aforementioned lever means is releasably connected intermediate its ends to the second portion of the support means and releasably connected at the one end to the free end of the piston rod so that the lever means may be exchanged with a lever means of a different kind should the need arise.

For applications in which the overhead space for engaging a head of the threaded connector to be turned is extremely limited, the lever means may be a one-piece flat lever provided in the region of its other end with a suitable opening for engaging a head of the threaded connector to be turned, in which case the wrench has to be disengaged from the threaded connector after each forward stroke of the piston and re-engaged after each backward stroke.On the other hand, if the overhead clearance for application of the wrench is not extremely limited, the lever means preferably includes a ratchet drive, that is it comprises a pair of drive plates each pivotable intermediate its ends about the appropriate pivot axis and pivotally connected at one end to the free end of the piston rod and being formed in the region of the other end with a circular opening, a ratchet gear being located between said pair of drive plates and having a pair of opposite trunions turnably mounted in the opening of the drive plates and provided with a coaxial opening for receiving the connector and a ratchet pawl located between said pair of drive plates pivotally connected at one end thereto and engaging with its other end a respective tooth of the ratchet gear.

The support means is preferably of substantially triangular outline having one corner at the first portion and two corners at the second portion, the pivot axis with the cylinder being located in the region of the one corner, and the pivot axis with the lever means being located at one of said corners with the second portion forwardly of the first-mentioned pivot axis and said at least one roller being located at the other corner of said second portion rearwardly of the first-mentioned pivot axis.

Preferably, the first portion of the support means is wider than the second portion and comprises two transversely spaced side walls between which said front end of said cylinder is located and the second portion preferably has a bifurcated front end portion receiving a portion of said lever means intermediate the ends thereof and an integral rear end portion carrying said at least one roller at one side thereof. Preferably, the construction includes two rollers provided respectively on opposite sides of said integral rear end portion.

A wrench in accordance with the invention will now be described in some detail, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a partially sectioned side view of the wrench, the section being taken along the line I-I of Fig. 2, Figure 2 is a front view of the wrench shown in Fig. 1, Figure 3 is a front view of a modified lever means for use in applications in which the overhead space for applying the wrench of Figs. 1 and 2 is extremely limited, and Figure 4 schematically shows a threaded connector connecting a flanged member to another member in which the overhead space for applying the wrench is extremely limited.

Referring now to the drawings and first to Figs. 1 and 2, it will be seen that the illustrated hydraulic wrench according to the present invention comprises support means 1 of substantially triangular outline having a first wider portion 1 a and a second narrower portion 1 b integral with the first portion. The first wider portion 1 a forms a pair of transversely spaced side walls 2 and the second portion 1 b has a bifurcated front or left end, as viewed in the drawing forming a pair of cheeks 3 transversely spaced from each other a distance smaller than the spacing of the side walls 2 and rearwardly joined to each other by an integral portion 4.A frame 5 attached in any convenient manner to the front end or left end of a hydraulic cylinder 6 having an axis Y, carries a pair of trunions 7 respectively projecting to opposite sides of the frame which are pivotally mounted in aligned circular openings 8 of the side walls 2 so that the cylinder 6 may pivot in the region of its front end about a pivot axis X located adjacent to the upper corner of the support 1 of triangular outline and normal to the axis Y of the cylinder. A piston 9 is reciprocatably arranged in the cylinder 6, movable between an active forward stroke towards the left, as viewed in Fig. 1, and a return stroke by alternately feeding and respectively discharging a hydraculic fluid to and from opposite ends of the cylinder 6, by means known per se and not shown in the drawings.A piston rod 10 coaxially fixed at one end to the piston 9 for reciprocation therewith projects with its free end 1 0a beyond the front end of the cylinder 6.

Lever means 11 located between the checks 3 of the bifurcated front end of the second portion 1 b of the support means 1 is pivotally attached by means of a pivot pin 1 2 for tilting about a second pivot axis Z parallel and located forwardly and downwardly from the first pivot axis X.In the embodiment shown in Figs. 1 and 2, this lever means 11 comprises a pair of drive plates 1 3 pivotable intermediate its ends about the pivot pin 1 2 and pivotally connected at the upper end, as viewed in Figs. 1 and 2, to the free end 1 0a of the piston rod by a pivot pin 1 4. The pair of drive plates 1 3 is provided in the region of its other or lower end with aligned circular openings 1 5 in which opposite trunions 1 6 of a ratchet gear 1 7 are respectively turnably arranged.The lever means 11 comprises further two ratchet pawls 1 8 fixed at their rear ends in any convenient manner into a cutout of a pivot pin 1 9 located forwardly of the pivot pin 12, whereas the front ends of the two ratchet pawls 1 8 respectively engage adjacent teeth of the ratchet gear 1 7. A leaf spring 20 fixed by a screw 21 in the region of one end to the periphery of the pivot pin 1 9 slidingly engages, in the region of its upper end, a pin 22 extending above the pivot pin 1 9 between the drive plates 1 3 and for instance releasably connected thereto by a pair of screws 23 as best shown in Fig. 2, to hold the front ends of the ratchet pawls 1 8 during the forward stroke of the piston in engagement with the respective teeth of the ratchet gear 1 7 while permitting, during the return stroke of the piston 9, the pawls 1 8 to ratchet over the teeth of the ratchet gear 17. The ratchet gear 1 7 is provided with an opening 24 for engagement with the threaded connector 25 to be turned. In Figs. 1 and 2 the connector 25 is shown as a conventional hexagonal head of a nut or the like but it should be appreciated that any shape of threaded connector can be used provided drivable connection can be made with it via an appropriately shaped opening 24.Preferably the arrangement further includes a spacer pin 26 located between the drive plates 1 3 spaced from the pin 22 adjacent the periphery of the ratchet gear 1 7 as best shown in Fig. 1 and the length of the spacer pin 26, as well as that of the pin 22 is slightly larger than the width of the ratchet pawls 18, so that the latter may freely tilt without engaging the drive plates 1 3.

The arrangement further includes at least one roller 27 turnably connected to the region of the rear end of the second portion 1 b of the support means 1 by means of a pivot pin 28 having an axis I parallel to and located downwardly and rearwardly of the axis X. This at least one roller 27, is located to the outside of one of the drive plates 13, that is it is axially displaced in the direction of the axis I from the ratchet gear 1 7 which is located between the two drive plates 1 3. Preferably the arrangement includes two rollers 27 respectively located to the outside of the two drive plates 13, as clearly shown in Fig. 2.

The above-described arrangement will operate as follows: It will be assumed that the wrench is used for turning the polygonal head, for instance a nut 25, about a threaded stud S, the lower end of which is threaded into a bore of a member M2, as shown in Fig. 4, to press the flange F of a member M, against the end face of the member M2. A plurality of such threaded connectors, which have to be successively turned, are spaced circumferentially from each other inwardly of the peripheral surface 29 of the flange F.In order to turn the nut 25 the same is engaged into the opening 24 of the ratchet gear 1 7 and during the forward stroke of the piston 9 in the cylinder 6 the drive plates 1 3 will swing about the axis of the stud S, so that the ratchet pawls 1 8 will drive the ratchet gear 1 7 in counterclockwise direction as indicated by the arrow a in Fig. 1 to tighten the nut 25 so as to press the bottom face of the flange F against the top face of the member M2.The pressure fluid fed, during the forward stroke of the piston 9, against the rear face of the latter acts also on the closed rear end of the cylinder 6 and since the front end thereof is attached by the pivot pin 7 to the upper corner of the triangular support means 1, a reaction force will also be created tending to turn the support means 1 in a direction opposite to the direction indicated by the arrow a about the axis of the pivot pin 1 2 in the opposite direction. This reaction force is taken up by the roller 27 rollingly engaging the peripheral surface 29 of the flange F At the same time, since the only fixed point is the axis of the stud S, the whole support means 1 will, during the active forward stroke of the piston 9 move forwardly swinging about the axis of the stud S, whereby the roller 27 will roll along the peripheral surface 29 of the flange F.By pivotally attaching the lever means 11 intermediate its ends to the support means 1, this forward movement of the support means provides an additional force for turning the ratchet gear 1 7 in the direction of the arrow a while the whole arrangement swings about the axis of the stud S. By attaching the front end of the cylinder 6 to the upper corner of the triangular support means 1 the whole arrangement becomes very compact so as to be easily handled.

The main advantage of the construction described is the roller 27 which rollingly engages the flange F, whereby the sliding friction according to the prior art construction is transformed into a rolling friction greatly increasing the efficiency of the hydraulic wrench. A further advantage of a wrench according to the present invention is that successive nuts may be tightened regardless of the spacings of the nuts from each other since the counteracting means, in the form of the roller 27, does not have to engage an adjacent nut, but engages the surface 29 of the flange F so that it is possible to successively turn a plurality of nuts which are spaced a considerable distance from each other.

There are also various applications in which the overhead space H, as shown in Fig. 4, for applying a wrench to the nut 25 is smaller than the spacing W (see Fig. 2) of the outer surfaces of the drive plates 1 3 from each other. For this purpose the lever means 11, including the two transversely spaced drive plates 13, is releasably attached by the pivot pin 14 to the free end 1 Oa of the piston rod 10 and also releasably attached by the pivot pin 1 2 to the front end of the second portion 1 b of the support means 1, so as to be replaceable by another lever means 30, as shown in Fig. 3.This lever means 30 is a one-piece substantially flat lever having an upper bifurcated end 30a between the two arms of which the free end 1 Oa of the piston rod is located and releasably attached thereto by the pivot pin 14. The one-piece flat lever 30 is pivotally and releasably attached intermediate its ends by the pivot pin 1 2 to the front end of the lower portion of the triangular support means 1, whereby preferably a pair of spacer rings 31 are located on opposite sides of the lever about the pivot pin 1 2 for holding the lever means 30 centrally between the cheeks 3 of the bifurcated front end of the support means 1 and in the region of its other or lower end the lever means 30 is formed with a suitably shaped, normally polygonal, opening 32 for engagement with the head of tne threaded connector to be turned.

With this construction, the lever means 30 has to be disengaged after the forward stroke of the piston from the threaded connector and reapplied to the latter after the return stroke of the piston. Of course in this construction feeding and discharging of pressure fluid to and from opposite ends of the cylinder has to be manually controlled in a manner known per se and not shown in the drawings so as to enable the operator to disengage the lever means 30 from the connector to be turned at the end of the forward stoke and to reapply the lever means 30 to the connector at the end of the rearward stroke.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of hydraulic wrenches differing from the types described above.

While the invention has been illustrated and described as embodied in a hydraulic wrench for successively turning the heads of threaded connectors arranged spaced from each other and inwardly of the outer surface of a flange in which the force created during turning of the threaded connector in one direction tending to turn the support of the wrench in the opposite direction is taken up by a roller rollingly engaging the outer surface of the flange, it is not intended to be limited to the details shown in the drawings, since various modifications and structural changes may be made without departing from the scope of the present invention as defined in the following

Claims

claims. CLAIMS

1. A hydraulic wrench for tightening or loosening threaded connectors connecting a flange to a member, said wrench comprising support means having a first portion and a second portion integral with the first portion; hydraulic operating means comprising a cylinder having an axis and being connected to the first portion of the support means, a piston axially reciprocatable in said cylinder and a piston rod connected at one end to the piston and having an opposite free end, lever means connected intermediate its ends to said second portion of said support means pivotable about a pivot axis transverse to said cylinder axis, said lever means being pivotally connected at one end to said free end of the piston rod and being provided in the region of its other end with means for engaging a threaded connector to be turned, whereby during such turning of a threaded connector in one direction a force is created tending to turn said support means in the opposite direction about said pivot axis; and at least one roller mounted on the second portion of the support means rearwardly of said pivot axis and spaced in the direction of the latter from said lever means, said roller being turnable about an axis substantially parallel to said pivot axis and being adapted to roll along the periphery of the flange for counteracting said force.

2. A hydraulic wrench as claimed in claim 1, wherein the cylinder is pivotable about a first pivot axis transverse to the cylinder axis, and wherein the lever means is pivotable about a second pivot axis substantially parallel to the first pivot axis.

3. A hydraulic wrench as claimed in claim 2 wherein the cylinder has a front end beyond which the piston rod projects and wherein the cylinder is pivotably mounted, in the region of its front end, about said first pivot axis.

4. A hydraulic wrench as claimed in any preceding claim, wherein the lever means is releasably connected intermediate its ends to the second portion of the support means and likewise is releasably connected at said one end to the free end of said piston rod.

5. A hydraulic wrench as claimed in any preceding claim, wherein the lever means is a one-piece flat lever provided in the region of its other end with an opening for engaging a head of a threaded connector to be turned for applications at which the overhead clearance for applying the wrench is extremely limited.

6. A hydraulic wrench as claimed in claim 5, in which said opening is of polygonal shape.

7. A hydraulic wrench as claimed in any preceding claim, wherein the lever means includes a ratchet drive.

8. A hydraulic wrench as claimed in any of claims 1 to 4, wherein said lever means comprises a pair of parallel transversely spaced drive plates each pivotable intermediate its ends about the pivot axis with the support means and pivotally connected at one end to said free end of said piston rod and being formed in the region of its other end with a circular opening, a ratchet gear located between said pair of drive plates and having a pair of opposite trunions turnably mounted in the openings of said drive plates and provided with a coaxial opening for engaging a head of a threaded connector to be turned and a ratchet pawl located between said pair of drive plates pivotally connected at one end thereto and engaging with its other end a respective tooth of said ratchet gear.

9. A hydraulic wrench as claimed in claim 8, in which the opening to receive the head of the connector is of polygonal shape.

10. A hydraulic wrench as claimed in claim 2 or any claim dependent thereon, wherein said support means is of substantially triangular outline having one corner at said first portion and two corners at said second portion, said first pivot axis being loocated in the region of said one corner, said second pivot axis being located at one of said corners at said second portion forwardly of said first pivot axis and said at least one roller being located at the other corner of the second portion rearwardly of said first pivot axis.

11. A hydraulic wrench as claimed in claim 10, wherein said first portion of said support means is wider than said second portion and comprising two transversely spaced side walls between which said front end of said cylinder is located, said second portion having a bifurcated front end portion receiving a portion of said lever means intermediate the ends thereof and an integral rear end portion carrying said at least one roller at one side thereof.

1 2. A hydraulic wrench as claimed in claim 11, wherein two rollers are provided respectively located at opposite sides of said integral rear end portion.

1 3. A hydraulic wrench substantially as hereinbefore described with reference to, and as illustrated in Figs. 1 and 2 of the accompanying drawings.