EP0725709A1

EP0725709A1 - Tightening spanner

Info

Publication number: EP0725709A1
Application number: EP94929417A
Authority: EP
Inventors: Daniel Octaaf Ghisla Torrekens
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-10-25
Filing date: 1994-10-25
Publication date: 1996-08-14
Anticipated expiration: 2014-10-25
Also published as: AU7849094A; DE69404666D1; US5823075A; WO1995011776A1; BE1007526A3; DE69404666T2; EP0725709B1

Abstract

A hydraulically-powered tightening and loosening spanner including a ratchet wheel assembly (5.1), a retaining mechanism (1.3), a drive lever (2) connected to a piston rod and fixedly supporting a guide (5.5), and a member rotating the ratchet wheel assembly and including a slide (5.4) which supports one or more drive elements (5.2) and is slidable along the guide during reciprocal motion of the piston (4.2).

Description

"Tightening wrench"

The present invention relates to a tightening and loosening wrench with hydraulic actuation respectively, of the type mentioned in the preamble of claim 1.

In US-A-4201.099 a hydraulic tightening wrench is described which has a housing unit / cylinder made in one piece. This execution involves high production costs, since the housing is difficult to machine. The ratchet wheel of this invention has a wide pitch toothing, which creates problems lor.3 in use when the elastic deformation of the rotating elements of the assembly makes them perform a return movement or when the 'support element to contain the reaction forces undergoes bending such that the key cylinder must perform a too large idle stroke.

The hydraulic tightening wrenches described in DE-A-36 20 753 Al and DE-A-34 16 881 Al each have an external casing which is used both for housing and for taking the reaction of the hydraulic cylinder. . This has the consequence that the exterior dimensions of the housing are necessarily large or that the hydraulic service pressures must be increased by a significant value. This extremely high operating pressure means that protection against cracking is required.

In DE-A-36 20 753 A1, the ratchet wheel shows very fine teeth as well as the driving element. This type of teeth avoids the disadvantages described above of the teeth of the key of US-A-4,201,099, but it does on the other hand present the danger of breaking small teeth which is inevitably caused by the gash effect suffered by such teeth. There are also known hydraulic tightening wrenches having ratchet wheels whose notches have rounded sides and rounded driving elements in the form of cylindrical rods or a ratchet with rounded end (see EP-A-0276936, EP-A- 0179543 and US-A-4663997).

The object of the invention is to eliminate all the disadvantages described above and to obtain a hydraulically actuated tightening key which is both resistant to wear and does not present a risk of premature breakage. It is also desirable that the key according to the invention have a relatively low weight and reduced dimensions, and allow efficient and safe use, while maintaining a long service life, even when used at full load. It is also necessary that the guiding of all the elements of the key is safe and does not allow possible wedging.

To solve these problems, there is provided, according to the invention, a key as described at the beginning, in which the drive lever fixedly supports a slide and the rotary drive member comprises a slide which supports the or the driving elements and which is capable of sliding along the slide during the reciprocating movement of the piston. This embodiment allows the driving element (s) to better support the rotational movement of the ratchet wheel. It allows extremely effective cooperation between the rounded drive element or elements and the rounded flanks of the ratchet wheel, during the forward stroke of the piston rod. Advantageously, the key according to the invention further comprises a compression spring arranged between the drive lever and the slide so as to keep the slide and its drive element (s) in pressure between the slide and the ratchet wheel means. According to an improved form of the invention, the drive lever and the slider present means of mutual engagement which additionally guide the slider in its movement of slide ent with respect to the slide. These mutual engagement means notably limit the axial movement of the slider and prevent it from making a movement with respect to the slide other than a slide.

To further improve the cooperation between the ratchet wheel and the driving element (s) throughout the duration of the forward stroke of the piston rod, the slide can support a cradle which is mounted in the slide pendulumly around a axis parallel to the axis of the ratchet wheel means and in which is or are housed the driving element (s). Preferably, the cradle supports at least two parallel driving elements and arranged at a mutual distance equal to a dev.art between two notches of the ratchet wheel means. This latter embodiment makes it possible to distribute the load simultaneously over several notches of the ratchet wheel. Preferably, the drive elements are supported in housings of the drive member from which they partially project, but from which they cannot come out during the operation of the key.

Other details and particularities of the invention will emerge from the description given below, without implied limitation and with reference to the attached drawings. FIG. 1 represents a view in longitudinal section, partially broken, of a hydraulic tightening wrench according to the invention.

FIG. 2 represents a cross-sectional view of this key, along line II-II of FIG. 1.

FIG. 3 represents a view in longitudinal section of another embodiment of the key according to the invention. FIG. 4 represents a profile view of the cradle used in the key illustrated in FIG. 1.

FIG. 5 represents a partially broken front view of this cradle, in the direction of the arrow FI in FIG. 4.

FIG. 6 shows a side view, partially broken, of the slide implemented in the key illustrated in FIG. 1.

FIG. 7 represents a front view, partially broken, of this slide, in the direction F2 of FIG. 6.

Figure 8 shows a sectional view of a detail of the assembly of an alternative embodiment according to the invention. In the various drawings, identical or similar elements bear the same references.

The hydraulic tightening key, as shown in FIGS. 1 and 2, comprises a housing 1 with two lateral faces 1.21, in which there are bores 1.22 provided with nozzles 1.1 for guiding an adapter 3.

On the rear face 1.23 of the housing 1 an opening 1.24 is provided, through which a hydraulic cylinder 4 can be mounted by pressing assembly. The front face of the housing 1 is fully open. Through this opening, a drive lever 2 with the integrated ratchet system 5 is introduced into the housing 1. After mounting the drive lever, the front face of the housing 1 is closed by a cover 1.2.

The drive lever 2, as shown on the fie -e 2, is machined in its front part in the form of a fork (on the left in FIG. 1), so that one can insert between the eyes of the lever 2.21, a ratchet wheel 5.1 of the ratchet system 5.

The eyelets of the drive lever 2.21 are provided with coaxial bores 2.22, which have approximately the size of the bores 1.22 of the side faces 1.21 of the housing 1.

In these bores 2.22 are mounted nozzles 2.1 after introduction of the ratchet wheel 5.1. 2.1 the nozzles are slid in the side chambers 5.11 of the ratchet wheel 5.1, to maintain it c ^"coaxially to 2.21 eyelets of the drive lever 2. The ratchet wheel is 5.1 at this time freely rotatable on the flanges nozzles 2.1.

In its upper, rear part, the drive lever 2 has a transverse bore 2.23 provided with nozzles 2.2, this bore being parallel to the bores 2.22 and allowing an articulated connection, by means of the axis 2.3, with a rod 4.3 of the piston 4.2 of the hydraulic cylinder 4.1. In the exemplary embodiment illustrated, the rod 4.3 has the shape of a fork at this end.

In a bore of the drive lever 2, whose axis extends in the plane of Figure 1, between the axes of the holes 2.22 and 2.23, is mounted a runner 5.5 which, in this embodiment, is cylindrical in shape and is fixed axially in position by a stop plate 5.6. On the slide 5.5 is mounted a member for rotating the ratchet wheel means. In this exemplary embodiment, this drive member comprises a slide 5.4 which is capable of moving in the longitudinal direction of the slide 5.5 (see also Figures 6 and 7). In order to prevent the slide 5.4 from being able to raise too much with respect to the slide 5.5, the latter is guided over a limited distance in oblong holes 2.24 of the drive lever 2, by means of two pins 5.9 fixed on each side of the slide 5.4 in lateral holes 5.20. In the embodiment illustrated in Figures 1 and 2, the drive member further comprises a driving cradle 5.3 which is connected to the coulis¬ bucket 5.4 by means of pins 5.7 housed in lateral holes 5.21 of the top 5.22 of the cradle. The top of the cradle has an arcuate shape and it can be housed in a corresponding arcuate groove 5.23 at the bottom of the slide 5.4. The lateral sides of this groove 5.23 are provided with oblong holes 5.24, also arcuate, into which the pins 5.7 penetrate. This arrangement thus allows limited tilting of the driving cradle 5.3 relative to the slide 5.4, and this around an axis parallel to the axis of the ratchet wheel 5.1.

In this exemplary embodiment illustrated in Figures 1 and 2, the drive member further comprises two drive elements in the form of rods preferably of circular section 5.2 which cooperate with the notches 5.12 of the ratchet wheel. These rods are mounted in housings 5.25 open towards the bottom of the driving cradle 5.3, so as to be able to slide axially therein. However the opening down of 5.25 housings is less than the diameter of the rods 5.2, which allows them to protrude from their housing towards the ratchet wheel without being able to leave this housing. The slide 5.4 and the driving cradle 5.3 are, in the illustrated embodiment, pushed back together by at least one pressure spring 5.8 in the rear position, so that the slide 5.4 is supported on the slide 5.5 and that the elements coaches in the form of cylindrical rods 5.2 mesh with the notches 5.12 of the ratchet wheel 5.1. This has notches, the front flanks of which, in the direction of rotation R of the ratchet wheel, have a profile of rounded shape corresponding to that of the driving elements 5.2 in cross section. A large surface support of the driving elements on the front sides of the notches as well as a force transmission with perfect guidance of all the elements of the driving member are thus guaranteed, not only at the start of the rotation of the ratchet wheel, but for almost the entire duration of its advancement by one step. This ensures an optimal connection between the drive lever 2 and the ratchet wheel 5.1. In addition, these notches 5.12 have a gradually sloping rear flank. A flat spring 1.3 shown in the figure

1 meshes with a suitable shape in one of the notches 5.12 of the ratchet wheel 5.1. The pressure force exerted by the spring 1.3 on the ratchet wheel 5.1 is such that during a forward movement of the drive lever 2, the spring 1.3 can pass over the teeth by sliding on the progressive slope of the rear flank of the notch 5.12. When the drive lever 2 goes back, the spring pressing force keeps the ratchet wheel 5.1 in position while the driving cradle 5.3 and the slide 5.4 slide over the toothing of the ratchet wheel

5.1 by applying pressure on the spring 5.8.

In the embodiment illustrated in FIG. 1, the hydraulic actuation cylinder 4 comprises a cylinder 4.1 having a cylinder bottom 4.11 integrally with it and a front shoulder 4.12. At the end of the cylinder opposite to that of the bottom 4.11 and directed towards the interior of the housing, the cylinder is provided with a guide nozzle 4.5. Through it passes an extension of reduced section 4.21 of a piston

4.2 which is capable of sliding inside the cylinder. This piston 4.2 is hingedly connected to one end of a piston rod 4.3 with a spherically shaped head 4.31. At its other end, this piston rod forms a fork 4.32 in which are provided bores allowing the passage of the axis 2.3 serving for the articulated connection between the piston rod 4.3 and the drive lever 2.

The spherical head 4.31 of the piston rod 4.3 is housed in a spherical cavity of the piston. It is held there axially by a ring 4.4 of elastic material which is inserted between the spherical head 4.31 and an internal rib of the extension 4.21 of the piston 4.2. This arrangement thus allows tilting of the piston rod 4.3 around its spherical head during the rectilinear movement of the piston 4.2 itself.

A first supply channel 4.13 opens in a rear chamber of the cylinder 4, in front of one of the front faces of the piston, and it brings a fluid under pressure to allow the forward stroke, known as working. A second supply channel 4.14 is drilled on the side through the wall of the cylinder parallel to the bore of the cylinder and it opens out via a connection channel 4.15 into a front chamber of the cylinder. This channel conducts the fluid under pressure to the return stroke of the piston. The piston 4.2 is guided by its reduced section extension 4.21 in the guide nozzle 4.5 during its outward and return strokes.

When the pressurized fluid is brought through the first supply channel 4.13, the piston

4.2 moves to the housing 1 and rotates the drive lever 2 to the left in Figure 1 around the axis of the ratchet wheel. At this time, the cylindrical driving elements 5.2 of the driving cradle 5.3 mesh in the notches in the form of an arc of a circle 5.12 of the ratchet wheel 5.1.

The driving cradle 5.3 can be positioned pendulumly in the arcuate groove 5.23 of the slide 5.4, so that the cylindrical rods 5.2 of the driving cradle 5.3 fit perfectly in the front flanks of the notches of the wheel to ratchet 5.1.

The slide 5.4 and the driving cradle

5.3 are kept in pressure between the slide 5.5 and the ratchet wheel 5.1 by the spring 5.8, so that the ratchet wheel 5.1 is driven in the direction R during the pivoting to the left of the drive lever 2 (see figure 1 ). During this time, the rear flanks of the teeth of the ratchet wheel 5.1 slide under the spring 1.3.

During this forward movement, the ratchet wheel is locked in abutment against the drive member driven by the actuating lever. Consequently, it transmits this rotational movement to the adapter 3, or directly to an element to be screwed or unscrewed. The adapter may have a suitable, suitable embodiment. Advantageously, it can have a profile called "polygon" as illustrated in FIG. 1. The adapter is placed on the head of a fixing element, for example a hexagonal nut, and it rotates this by the value of l swivel angle of the drive lever. The adapter 3 can be inserted on each side into the housing 1. It is held axially in the latter on the opposite side by an intermediate ring 3.1 with bayonet attachment 3.11.

For the return movement of the piston 4.2, the pressurized fluid is supplied via the second supply channel 4.14 while the pressurized fluid located in the rear chamber of the cylinder can return freely (without pressure) to the reservoir of the hydraulic unit through channel 4.13. At this time the drive lever 2 is returned to its initial position to the right (see Figure 1). During this time, the ratchet wheel 5.1 is held in position by means of the spring 1.3 to prevent its rotation towards the rear.

The driving cradle 5.3 and the slide 5.4 are brought back and the spring pressure 5.8 allows the cylindrical rods 5.2 of the driving cradle 5.3 to slide to the right (see figure 1) over the rear flanks of the wheel teeth ratchet 5.1.

When loosening nuts that have been tightened or strongly corroded, it can happen that these suddenly loosen by making a fairly violent and sudden backward rotation after applying a certain torque to them. At this time, fairly high inertia forces are transmitted in the various components of the hydraulic tightening key, and they can cause its destruction or damage it.

If, for example, a nut suddenly loosens, the drive lever 2 will want to follow this sudden movement. The piston rod 4.3 and the piston 4.2, which are connected to the lever 2, cannot follow this sudden movement because of the moments of inertia and they may thus, in the event of negative circumstances, be damaged or destroyed.

To avoid this kind of drawback, the ring 4.4 made of elastic material makes it possible to absorb and absorb the shocks due to the phenomena described above.

The reaction plug element 6 (see FIG. 1) is in fact an element of annular shape with a lateral offset not shown. The inner contour of the reaction arm 6 has the same shape as the outer contour of the actuating cylinder 4. It is slid over the cylinder 4 and can be locked in several positions thereon in the longitudinal direction by means of pins. To do this, the cylinder is provided on its wall with semicircular grooves in which the goupil¬ les can be locked.

This reaction arm 6 allows the hydraulic key to absorb the reaction torque. This must be applied against a sufficiently strong support. For example, a screw head located near or the outside of a flange.

In the embodiment according to FIG. 1, the hydraulic actuating cylinder is mounted from the inside of the housing in the transverse axis and is pressed through an adequate opening in the latter until it stops against a shoulder 4.12 made for this purpose.

In an alternative embodiment (see Figure 8), the shoulder is replaced by one or more pins 1.25 located midway between the contact surface between the hydraulic cylinder 4.1 and the opening in the housing.

This attachment is an additional safety device preventing the hydraulic cylinder from sliding inside the housing. Another embodiment of the key according to the invention is illustrated in FIG. 3. This key differs from the key according to FIGS. 1 and 2 by the fact that it comprises only a single drive rod 5.2 with cross-section. circular. Given this, a tilting movement of the rod 5.2 relative to the slide proves less necessary than in the embodiment according to Figures 1 and 2. This explains the absence of the driving cradle and the housing of the rod. 5.2 drive directly in the slide 5.4.

In this embodiment, the ratchet wheel itself has a central bore 5.13 in the form of a square. It should be understood that the present invention is in no way limited to the forms of embodiment described above and that many modifications can be made without departing from its scope.

One can for example provide a greater number of driving elements 5.2, for example three or more. The section of these could have a curve different from the circle, provided that the notches have a front flank of corresponding curvature.

One can also imagine other retaining mechanisms than the flat spring 1.3.

One can also imagine central bores of the ratchet wheel of hexagonal shape or other.

Claims

CLAIMS 1. Hydraulically actuated tightening and loosening wrench, comprising a housing (1), a hydraulic actuation cylinder (4) which is housed in the housing (1) and in which a piston (4.2) provided with a piston rod (4.3) can be moved back and forth, a drive lever (2) connected to the piston rod (4.2) in an articulated manner, a ratchet wheel means (5.1) which is mounted in the housing (1) so as to be able to rotate about an axis, is capable of being adapted to an element to be tightened or loosened, and is provided at its periphery with notches (5.12), having sidewalls which at least partially have a rounded shape in profile, a member for rotating the ratchet wheel means (5.1) supported by the driving lever (2) and comprising at least one driving element (5.2) cooperating with said rounded flanks of said notches (5.12) of the ratchet wheel means to cause it to rotate in a first direction of rotation (R), during a forward stroke of the reciprocating movement of the piston (4.2), and a retaining mechanism (1.3) which cooperates with the means of ratchet wheel (5.1), and prevents it from turning in a second direction opposite to the first direction (R) above, during a return stroke of the reciprocating movement of the piston (4.2), characterized in that the lever of drive (2) fixedly supports a slide (5.5) and in that the rotary drive member also takes a slide (5.4) which supports the drive element (s) (5.2) and which is able to slide along the slide (5.5) during the reciprocating movement of the piston (4.2). 2. A tightening key according to claim 1, characterized in that it comprises a compression spring (5.8) arranged between the drive lever (2) and the slide (5.4) so as to keep the slide (5.4) under pressure. ) and its driving element (s) (5.

2) between the slide (5.5) and the ratchet wheel means (5.1).

3. A wrench according to either of claims 1 and 2, characterized in that the drive lever (2) and the slide (5.4) presen¬ mutual engagement means (2.24, 59 ) which additionally guide the slide in its sliding movement relative to the slide (5.5). 4. A wrench according to any one of claims 1 to 3, characterized in that the slide (5.

4) supports a cradle (5.3) which is mounted in the slide pendulum about an axis parallel to the axis of the ratchet wheel means (5.1) and in which is or are housed the driving element (s) (5.2).

5. A wrench according to any one of claims 1 to 4, characterized in that the cradle (5.3) supports at least two driving elements (5.2) parallel and arranged at a mutual distance equal to a distance between two notches (5.12) of the ratchet wheel means (5.1).

6. Tightening key according to any one of claims 1 to 3, characterized in that the slide (5.4) directly supports at least one driving element (5.2).

7. Tightening wrench according to one of claims 1 to 6, characterized in that each driving element (5.2) is formed by a rod with circular section and with longitudinal axis parallel to the axis of the wheel ratchet (5.1).

8. Tightening wrench according to one of claims 1 to 7, characterized in that each driving element (5.2) is arranged in a housing (5.25) of the driving member having an opening towards the wheel means hook (5.1), by which the driving element protrudes to enter a notch (5.12) of the hook wheel, without being able to come out of this housing.

9. A wrench according to any one of claims 1 to 8, characterized in that the retaining mechanism comprises a spring element

(1.3) a part of which cooperates with at least one of said notches (5.12) during the return stroke of the piston (4.2).

10. A wrench according to any one of claims 1 to 9, characterized in that the piston (4.2) comprises a cavity which is open towards the inside of the housing (1), and at the bottom of which is mounted so articulated one end (4.31) of the piston rod (4.3).

11. A wrench according to claim 10, characterized in that a ring of elastic material

(4.4) is interposed between the piston cavity and the piston rod (4.3) so as to prevent an axial displacement of the latter in said cavity.

12. A wrench according to any one of claims 1 to 11, characterized in that the cylinder (4) is assembled to the housing (1) by pressing in an end wall (1.23) thereof.