EP2437998B1

EP2437998B1 - Tensioning element

Info

Publication number: EP2437998B1
Application number: EP10783646.2A
Authority: EP
Inventors: Lars Mikaelsson; Joakim Harr
Original assignee: Indexator Group AB
Current assignee: Indexator Group AB
Priority date: 2009-06-02
Filing date: 2010-05-31
Publication date: 2014-04-16
Anticipated expiration: 2030-05-31
Also published as: EP2437998A4; EP2437998A1; SE534078C2; SE0900754A1; WO2010140947A1

Description

This invention relates to a tensioning element for a swing damper according to the pre-characterising part of claim 1.

Technical field

When swing dampers are used to support different types of tools, e.g. suspended from a crane jib, it is desirable to achieve effective and reliable braking or damping of the oscillating movement/swinging movement that normally occurs, e.g. when operating the crane jib and performing different tasks.
Swing dampers can be used in association with all conceivable types of tools, e.g. suspended from a crane jib, e.g. in timber harvesters, forwarders, timber processors, log hoists, excavators, special-purpose machines, etc.. Swing dampers may be of either the single or double type, i.e. they can carry out damping/braking operations in one or two oscillating planes/swinging planes.
A swing damper of the abovementioned type is described in Swedish patent specification SE 0202945-2 ( SE 525863 ), to which reference should be made for a clearer understanding of the technical field in question.
WO 00/73195 A1 discloses a tensioning element according to the preamble of claim 1.
One problem encountered with swing dampers of the abovementioned type is how to achieve a mechanical tensioning element which does not lose the set degree of tightening during operation as a result of a tightening screw/adjusting screw gradually loosening during operation.

Aim of the invention

One aim of this invention is to provide an extremely advantageous tensioning element for a swing damper, the said tensioning element displaying, inter alia, very good adjustment stability. This aim is achieved in that the tensioning element has the features specified in claim 1.
The setting of the desired braking power is very simple and reliable.

Brief description of the drawings

An embodiment of the invention will now be described in more detail with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of a swing damper,
Figure 2 is an exploded view of the swing damper according to Figure 1 and
Figure 3 is a vertical section through the brake arrangement and tensioning element of the swing damper.

Detailed description of the illustrated embodiment

Figure 1 shows a swing damper 1, e.g. swing-mounted at the tip of a crane jib (not shown) via a swing joint/bearing 3 in such a manner that it can swing about an axis A.
The swing damper 1 supports at its lower end, e.g. a rotator 4 which in turn supports, e.g. a working tool in the form of a gripper (not shown). The swing damper 1 and the rotator/tool 4 can therefore swing relative to one another about an axis B. The swing damper 1 furthermore includes a brake arrangement 50 and a tensioning element 100.
The swing damper 1 includes two downwardly directed fastening lugs 20, 21 between which an upper bearing plane 22 is arranged. The fastening lugs 20, 21 comprise a circular hole 23 within which a circular plain bearing bush 24 is arranged.
The rotator/tool 4 includes two upwardly directed fastening lugs 30, 31 which embrace the downwardly directed fastening lugs 20, 21 in a fork-like manner, as will be clear from Figure 3. A lower bearing plane 32 is arranged between the upwardly directed fastening lugs 30 and 31. The fastening lugs 30, 31 comprise a circular hole 35.
A tensioning element 100 is provided so that the swing damper 1 and the rotator/tool are coupled and held together in such a manner that they can swing relative to one another.
The tensioning element 100 cooperates with the bearing bushes 24 so that the swing damper 1 and the rotator/tool 4 can swing relative to one another about the axis B.
The brake arrangement 50 includes a brake assembly 60 comprising a central brake disc 70 with brake linings and two outer brake discs 80.
The central disc 70 comprises upper bearing planes 71 which bear against the upper bearing plane 22 between the downwardly directed fastening lugs 20, 21 of the swing damper 1. This ensures that the disc 70 is locked against rotation relative to the swing damper 1. The lower part of the disc 70 comprises a semi-circular rounded portion 72 allowing for relative swinging movement of the disc 70 and the rotator/tool 4. The disc 70 comprises a circular central hole 73 within which a bearing 74 in the form of, e.g. a ball bearing is arranged. It is of course also possible to use other types of bearings. The disc 70 is provided on its side surfaces with annularly arranged brake linings 75, as will be clear from the figures.
The outer brake discs 80 comprise lower bearing planes 81 which bear against the lower bearing plane 32 between the upwardly directed fastening lugs 30 and 31 of the rotator/tool 4. This ensures that the brake discs 80 are locked against rotation relative to the rotator/tool 4. The upper part of the brake discs 80 comprises a semi-circular rounded portion 82 allowing for relative swinging movement of the brake discs 80 and the swing damper 1. The brake discs 80 comprise a circular central hole 83.
The tensioning element 100 is designed to compress the brake assembly 60 when braking operations are to be carried out.
The tensioning element 100 includes a pin 110 with a circular outer shape, a front circular shoulder 111 and a rear circular shoulder 112 being provided. A shoulder 113 is arranged between the shoulders 111 and 112. The pin 110 comprises an end collar 114 at its rear end. The pin 110 furthermore comprises a circular central hole 120 having a circular recess 121 at the front end of the pin 110. The circular central hole 120 turns into a square hole 122 at the rear end part of the pin 110 and the square hole 122 turns into a circular hole 123 at the rear end plane 124 of the pin 110.
A circular sleeve 130 displaceable along the shoulder 111 of the pin is arranged on the outside of the pin 110. The outer contour of the sleeve 130 cooperates with one bearing bush 24 and the shoulder 112 of the pin cooperates with the other bearing bush 24 so as to allow for swinging about the swing axis B. The sleeve 130 comprises a circular recess 131 at its free end 132.
The tensioning element 100 includes a tensioning screw/adjusting screw 140, the head 141 of which comprises a circular shoulder 142 for receiving a spring assembly 143 in the form of a plurality of cup springs. The shank 145 of the screw 140 comprises an external thread 146 for engagement with a nut 160. The tip 147 of the screw 140 has a hexagonal cross section and has smaller dimensions than the screw shank 145 so that the nut 160 can be applied to the screw thread 146. The screw head 141 does not have a key handle for screwing. Screwing is effected with a tool applied to the hexagonal part 147.
The nut 160 has a square outer contour which cooperates with the square hole 122 within which the nut 160 can slide axially but cannot rotate.
The tensioning element 100 furthermore includes an anti-rotation element 170 comprising a hexagonal hole 171 which cooperates with the hexagonal tip 147 of the tensioning screw 140 so that the anti-rotation element 170 can slide axially along the tip 147 but cannot rotate relative to the tip 147. The anti-rotation element 170 has a square outer contour which cooperates with the square hole 122 within which the anti-rotation element 170 can slide axially but cannot rotate.
A locking ring 180 is provided to keep the anti-rotation element 170 in the square hole 122, as will be clear from Figure 3. An outer sleeve coupling 172 on the anti-rotation element 170 has reduced dimensions so as to provide space for the locking ring 180 which is fixed in a groove 125 in the hole 123. The locking ring 180 thus ensures that the anti-rotation element 170 is secured in a position in which the tensioning screw 140 is always locked against rotation.
The tensioning element 100 is used to set the desired braking force of the swing damper 1. The tensioning element 100 is mounted centrally on the swing joint B in order to exert force on the brake arrangement 50 so as to result in swing damping. The pin 110 of the tensioning element 100 serves for the suspension of the accessory 4 to be subjected to swing damping. The sleeve 130 is displaceable along the shoulder 111 of the pin 110 in order to activate the brake arrangement 50. The adjusting screw 140 is designed to exert axial displacement force on the sleeve 130 via the spring assembly 143. The nut 160 is used to adjust the tightening force of the adjusting screw 140 and thereby set the braking power. The locking element 170 eliminates subsequent rotational movement of the screw 140 relative to the pin 110, as a result of which the set braking force is maintained.
The square hole 122 of the pin 110 locks the square nut 160 against rotation, although it can slide axially in the square hole 122. The locking element 170 is also locked against rotation by the square hole 122 but can slide axially therein. The hexagonal part 147 of the adjusting screw 140 cooperates with the hexagonal central hole 171 of the locking element 170 so as to allow for relative axial sliding movement while preventing relative rotational movement. A mounted locking element 170 thus ensures that the adjusting screw 140 is locked against rotation while simultaneously maintaining the desired brake spring force as the nut 160 cannot rotate and, e.g. vibrate and become loose.
When the desired braking force is being set or adjusted, the locking ring 180 and the anti-rotation element 170 are removed from the tensioning element 100. The desired spring force and braking force are then achieved in that the adjusting screw 140 is rotated in the desired manner by means of a socket tool engaging with the hexagonal part 147 of the screw 140. When the desired spring force or braking force has been set, the anti-rotation element 170 and the locking ring 180 are mounted so that the adjusting screw 140 is once again secured against rotation.
The risk of what is referred to as chattering of the nut 160/screw 140 assembly is eliminated by means of the invention.
A more natural direction of rotation for adjusting the tension can be achieved by designing the adjusting screw 140 and the nut 160 with left-hand threads.
It will of course be clear that the design of the components and the geometry of the anti-rotation device may be varied within the scope of this inventive concept.
The invention is thus not limited to the embodiment illustrated and described and changes and modifications are of course possible within the scope of the following claims.

Claims

Tensioning element for setting braking force in a swing damper, wherein the tensioning element (100) is mounted centrally on a swing joint (B) in order to exert force on a brake arrangement (50) so as to result in swing damping, wherein the tensioning element (100) includes a pin (110) serving for the suspension of an accessory (4) to be subjected to swing damping, a sleeve (130) displaceable along a shoulder (111) on the pin (110) in order to activate the brake arrangement (50), an adjusting screw (140) designed to exert axial displacement force on the sleeve (130) via a spring assembly (143) and a nut (160) for adjusting the tightening force of the adjusting screw (140) characterized in that the pin (110) comprises a circular central hole (120) which turns into a square hole (122) at the rear end part of the pin (110), and the shank (145) of the screw (140) comprises an external thread (146) for engagement with the nut (160), and the tip (147) of the screw (140) has a hexagonal cross section and has smaller dimensions than the screw shank (145) so that the nut (160) can be applied to the screw thread (146), and the tensioning element (100) furthermore includes a locking element (170) comprising a hexagonal hole (171) which cooperates with the hexagonal tip (147) of the screw (140), and the locking element (170) as well as the nut (160) have a square outer contour which cooperates with the square hole (122) so that rotational movement of the screw (140) relative to the pin (110) is eliminated.
Tensioning element according to claim 1, characterized in that a stop element (180) is designed to limit axial movement of the locking element (170).
Tensioning element according to claim 1 or claim 2, characterized in that the tip (147) of the screw (140) serves as a key handle when adjusting braking force, the locking element (170) and the stop element (180) being temporarily removed.