Hydraulically operated tightening tool

Abstract

The present invention relates to a hydraulically operated tightening tool comprising a body (1) in which there is assembled a hydraulic cylinder and an actuating ring (6) articulated to the body (1) which receives the action of the piston (3) of the hydraulic cylinder. Two axial tabs protrude from the head of the piston (3) between which tabs there is articulated the actuating ring (6) by means of a shaft with an elastically variable length protruding partially on both sides of the ring. The tabs (7) have transverse facing grooves (16) in which there are housed the ends of the mentioned shaft.

Claims

1. A hydraulically operated tightening tool comprising: a body comprising a hydraulic cylinder, the hydraulic cylinder comprising a piston, the piston comprising a head, wherein first and second tabs protrude from the head of the piston, wherein the first tab comprises a first arched groove, wherein the second tab comprises a second arched groove, the first and second arched grooves being transverse and facing each other, the first and second arched grooves opening at respective end sections through respective longitudinal edges of the first and second tabs, the piston having a first, retracted, position and a second, extended, position; an actuating ring for a threaded element, the actuating ring being articulated with respect to the body and adapted to receive an action of the piston of the hydraulic cylinder a spring having a first end and a second end, and an elastically variable length the spring being disposed in a manner to traverse the actuating ring perpendicularly first and second elements disposed respectively at first and second ends of the spring, wherein the first element protrudes from a first end of the actuating ring and fits in the first arched groove, wherein the second element protrudes from a second end of the actuating ring and fits in the second arched groove; wherein the actuating ring is articulated via the spring, the first element, and the second element; and a thrusting part disposed between the first and second tabs, the thrusting part resting on the piston of the hydraulic cylinder, wherein the actuating ring rests on the thrusting part wherein: the first element is disposed at a first end of the first arched groove and the second element is disposed at a second end of the second arched groove, the second end corresponding to the first end, when the piston is in the first, retracted position; and the first element is disposed at a third end of the first arched groove and the second element is disposed at a fourth end of the second arched groove, the third end corresponding to the fourth end, when the piston is in the second, extended, position.

2. A hydraulically operated tightening tool comprising a body in which there is assembled a hydraulic cylinder and an actuating ring for a threaded element, the actuating ring of which is articulated to the body and receives the action of the piston of the hydraulic cylinder for its swiveling, characterized in that two parallel tabs axially protrude from the head of the piston of the hydraulic cylinder between which tabs there is a spring with an elastically variable length, the actuating ring being articulated on the spring; the spring of which traverses the actuating ring perpendicularly and protrudes partially from same on both sides; and the tabs of which have respective arched transverse facing grooves, in which there are housed the ends of the mentioned spring, said grooves opening at their end sections through the longitudinal edges of the tabs, and in that between the tabs there is arranged a thrusting part on which the actuating ring rests, the part of which in turn rests on the piston of the hydraulic cylinder, wherein the spring with an elastically variable length is made up of a helical spring and of two spheres resting on the ends of the spring, one on each end, the spring of which traverses the actuating ring perpendicularly through a borehole having a diameter approximately equal to that of the mentioned spring; and each sphere being retained by a cage fixed to the ring, with the spring being compressed, and partially protrude into caps which are housed in the grooves of the tabs.

3. A hydraulically operated tightening tool comprising a body in which there is assembled a hydraulic cylinder and an actuating ring for a threaded element, the actuating ring of which is articulated to the body and receives the action of the piston of the hydraulic cylinder for its swiveling, characterized in that two parallel tabs axially protrude from the head of the piston of the hydraulic cylinder between which tabs there is a spring with an elastically variable length, the actuating ring being articulated on the spring; the spring of which traverses the actuating ring perpendicularly and protrudes partially from same on both sides; and the tabs of which have respective arched transverse facing grooves, in which there are housed the ends of the mentioned spring, said grooves opening at their end sections through the longitudinal edges of the tabs, and in that between the tabs there is arranged a thrusting part on which the actuating ring rests, the part of which in turn rests on the piston of the hydraulic cylinder, wherein the mentioned cages are made up of two plates, each plate housed and fixed in a slot of the actuating ring on its opposite surfaces and in matching positions, the plates of which have a circular central hole the outer opening of which is of a diameter less than that of the spheres, through which hole each sphere protrudes partially into a portion which is housed in the grooves.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The attached drawings show a tool made according to the invention and provided by way of non-limiting example. In the drawings:

(2) FIG. 1 is a side elevational view of a tool including the features of the invention.

(3) FIG. 2 is an exploded perspective view of the tool of FIG. 1.

(4) FIG. 3 corresponds to detail A of FIG. 2 on a larger scale.

(5) FIG. 4 is a longitudinal section of the tool taken according to section line IV-IV of FIG. 1.

(6) FIG. 5 is a partial section view of the tool taken according to section line V-V of FIG. 4.

(7) FIG. 6 is a view similar to FIG. 5 with the piston of the hydraulic cylinder in a position of maximum extraction.

(8) FIG. 7 shows the perspective view the tool of the invention with a reaction base applied thereon and with the given tightening holders for a nut or screw.

(9) FIG. 8 shows the perspective view of the way of applying the tool of the invention, with the reaction base included in FIG. 7.

DETAILED DESCRIPTION OF AN EMBODIMENT

(10) The constitution, features and advantages of the tool of the invention will be better understood with the following description of the embodiment shown in the drawings attached.

(11) FIGS. 1 to 3 show a tool comprising a body 1 demarcating a chamber 2 in which there is housed a piston 3 forming a hydraulic cylinder provided with connections 4 for connecting the hydraulic fluid from a hydraulic generation centre 5, FIG. 8.

(12) An actuating ring 6 for a threaded element is further assembled in body 1. This ring 6 is articulated inside the body 1 and receives the action of the piston 3 eccentrically with respect to the position of the articulation spring of the ring for swiveling same.

(13) According to the present invention, the ring 6 is assembled in an articulated manner at the end of the piston 3 by means of two tabs 7 which are integral with said piston and protrude from same axially. The actuating ring 6 is inserted between these tabs and is articulated therebetween by means of a spring with an elastically variable length which, in the example depicted in the drawings, is made up of a helical spring 8 traversing the actuating ring perpendicularly 6 through a borehole 9 having a diameter approximately equal to that of the spring 8. Respective spheres 10 each of them retained by a cage in the form of plates 11 housed and fixed in slots 12 of the actuating ring 6 on its side surfaces in matching positions, rest at the ends of this spring 8. The plates 11 can be fixed on the slots 12 by means of screws or rivets 13. These plates 11 will further have a central hole 14 which can have therein a spherical surface having radius coinciding with that of the spheres 10 and with an outer circular opening 15 having a radius less than that of said spheres.

(14) Once the set described is assembled in the actuating ring 6, the spring 8 is compressed, the spheres 10 protruding partially through the opening 15 of the holes 14.

(15) The tabs 7, between which there is assembled the actuating ring 6, have, on their facing surfaces, respective arched transverse matching grooves 16 opening at their end sections through the longitudinal edges of the tabs 7. The caps or portions of the spheres protruding through the openings 15 of holes 14 of plates 11 penetrate these grooves 16.

(16) Between the tabs 7 there is further arranged a thrusting part 17 resting on the piston 3 on which the actuating ring rests 6, all this as can be better seen in FIG. 4, in which the hydraulic cylinder is also seen, the hydraulic cylinder is made up of chamber 2 and piston 3 with tabs 7 integral thereto, which tabs define the grooves 16 in which there are housed partially the spheres 10 which, together with the spring 8, form the articulation spring for articulating the actuating ring 6 on the tabs 7.

(17) When the piston 3 is in the retracted position of FIG. 4, the actuating ring 6 occupies the position depicted in FIG. 5, in which the spheres 10 are located at one of the ends of the grooves 16. When the piston 3 moves forward until occupying a position of maximum extraction shown in FIG. 6, the actuating ring 6 will have rotated about the articulation spring established in the spheres 10 which will have moved along the grooves 16 until occupying position 10 of FIG. 6. The linear movement of the piston of the hydraulic cylinder from position 3 of FIG. 5 to position 3 of FIG. 6 will have swiveled the actuating ring from position 6 of FIG. 5 to position 6 of FIG. 6, rotating about the center 18 of the base 19 on which there is fixed the square 20 on which there can be coupled the socket with a size corresponding to the nut or screw on which the tool is to be coupled.

(18) When the force from actuating the tool exceeds a pre-fixed value during the operation of tightening or loosening a nut or screw, the balls 10 of the articulation spring between the actuating ring 6 and the tabs 7 exceed the end sections of the grooves 16, coming out from same and ceasing at this time the transmission force between the piston 3 of the hydraulic cylinder and the square 20 having the corresponding socket for actuating the nut or screw.

(19) Breaks or deteriorations in the components of the tool or of the threaded elements which it actuates are thus prevented. By means of backing away slightly from the position reached, the spheres 10 are housed again in the grooves 16, the tool being ready for new actuation.

(20) As shown in FIG. 7 a reaction base 21 is coupled on the described tool, which reaction base 21, as depicted in FIG. 8, rests at a fixed point of the structure 22 having the nuts to be tightened. Pressurized fluid is fed to the chamber 2 of the hydraulic cylinder of the tool by means of the hydraulic generation center 5 and through the connectors 4, causing the piston 12 to move in one direction or another, the rectilinear movement of which is converted into a circular movement in the actuating ring 6 which allows rotating the dice 20, FIG. 4 and thereby the socket fitted therein for actuating the nut 23. To assure that rotation about the nut does not occur in the wrench, the reaction base 21 resting at a fixed point of the structure 22 is provided.

(21) As discussed above, when a nut is to be loosened, there are cases where in view of the enormous tension to which the nut is subjected in the set formed by the screw and nut, friction force is overcome and it suddenly rotates faster than the actuating ring 6, dragging it in a first instant until the friction force balances again. Since the piston 3 moves slower and does not accompany the actuating ring 6 because the hydraulic fluid prevents same, said ring detaches from the tabs 7 when the spheres 10 come out of the grooves 16, thus preventing breaks or deteriorations from occurring in the system. Once the force ceases, the spheres 10 fit in the grooves 16 again because the force for loosening the nut continues being considerable.