EP0482158B1 - Device for transmitting forces to mobile bodies - Google Patents

Abstract

PCT No. PCT/DE91/00377 Sec. 371 Date Jan. 10, 1992 Sec. 102(e) Date Jan. 10, 1992 PCT Filed May 8, 1991 PCT Pub. No. WO91/18181 PCT Pub. Date Nov. 28, 1991.The jaws of a clamp are provided with elastomeric linings, and gripping elements of high hardness in the form of pins or particles are embedded in the linings. The gripping elements have tips which are directed away from the respective jaws.

Description

The invention relates to a device for introducing translational forces and / or torques into movable bodies with a layer or intermediate layer made of an elastomeric material arranged between the force-transmitting parts and the movable bodies.

When using devices of the aforementioned type, considerable clamping forces have to be generated, for example in order to be able to lift or even move heavy parts. Large torques are also required, for example, to screw or loosen pipes together. Knives are often used to securely transmit the clamping forces to the movable bodies, with which the clamping jaws are fitted. The knives or other elements which considerably increase the local surface pressure often damage the surfaces of the rigid bodies to be moved or lead to undesired impressions, so that the damaged body surfaces are increasingly exposed to corrosion. For this reason, stainless steel is increasingly being used for borehole pipes in oilfield technology. For this reason, a long service life is important for reasons of cost. A further disadvantage is that the clamping jaw knives are often difficult to detach from the detected surfaces of the bodies to be moved after they have been pressed into the material and the contact forces have been released. In particular this affects the loosening of clamping knives from a pipe after unscrewing, because after completely loosening a pipe from a connector it is very difficult to remove the clamping jaws from the unscrewed workpiece by reversing the direction of rotation; because a counter moment is no longer present.

According to US-A-3 799 010, it is known to place an elastic ring to improve the torque transmission between the force-transmitting parts and bodies to be rotated. Since the force-transmitting parts are a link chain, the non-positive connection is improved by inserting the elastic ring. It is also possible to combine the non-positive connection between the elastic ring and a pipe to be rotated with that of knife-shaped, metallic bodies. For this purpose, the ring made of an elastic material is provided with axially directed slots which penetrate the ring from the outer circumference to the inner circumference. The metallic bodies are inserted into the axially directed slots and are provided with sharpened edges on their two sides, which protrude from the circumferential and the inner surface. The internal edges press into the material of the pipe to be rotated when the force is absorbed. An injury to the pipe surface cannot be avoided.
US-A-2 765 000 shows a spacer for holding inner tubes in outer tubes. They have particles which increase the friction between the contact surfaces and which are connected to their base on the spacers, for example by gluing. When larger contact forces are absorbed, the sharp-edged particles damage the pipe surface. If dynamic forces were transmitted, the surface damage would undoubtedly be considerably greater.

The invention is based on the object of designing a device according to the generic term mentioned at the outset, that a damage-free attack of the jaws on the surfaces of the bodies to be detected and moved is made possible. The solution according to the invention is characterized in that the elastomeric material is arranged in the form of inserts in the clamping jaws of the device and serves as a carrier material for a large number of hard particles embedded therein with tips directed against the contact surfaces of the bodies to be clamped.

The invention enables the transmission of large translational forces or large torques directed perpendicular to the clamping forces to rigid bodies to be moved without damaging their surfaces and thereby exposing them to increased corrosion, largely independently of the material used. Bodies made of plastic can also be detected without disadvantages. This advantage is achieved by a wide-area, combined friction and form fit, the elasticity of the carrier material ensuring full-area contact between the insert and the surfaces to be detected even if they deviate from a precise flat or cylindrical shape and, for example, areas larger or less unevenness or curvatures.

The use of needle-shaped elements which are embedded in the carrier material is particularly advantageous. The attack-side ends of the needles extend essentially to the surface of the insert that is in contact with the body to be moved, while preferably the ends of the needles on the jaw side end at a distance from the contact surface of the elastomeric inserts on the clamping jaws. The elastomeric material located between the needle ends on the jaw side and the jaws can compensate for unevenness in the parts to be clamped, since the elastomeric material can laterally refill at high pressure.

Instead of the needles, other hard particles of granular shape can be used. Crystal grains of the same or different sizes made of diamond, glass, corundum, quartz, ceramic and the like are suitable for this.

Further features that advantageously shape the invention are specified in the subclaims.

In the drawing, exemplary embodiments of the invention for transmitting forces to bodies to be moved are shown purely schematically and explained below.

Fig. 1

den Querschnitt durch ein Rohr mit dieses umfassenden Klemmbacken,

Fig. 2

den Längsschnitt A-B durch die Vorrichtung gemäß Fig. 1,

Fig. 3

eine vergrößerte Darstellung eines Bereichs des Längsschnitts A-B,

Fig. 4

die vergrößerte Draufsicht auf einen Teil der Einlage mit eingebetteten nadelförmigen Teilen,

Fig. 5

die Anordnung von nadelförmigen Teilen mit einer Neigung zur radialen Richtung,

Fig. 6

die vergößerte Darstellung eines Längsschnittbereichs einer Einlage mit eingebetteten körnigen Partikeln,

Fig. 7

den Querschnitt durch eine Rohrkeilklemme mit Einlagen mit eingebetteten nadelförmigen Teilen,

Fig. 8

einen Längsschnitt durch die Rohrkeilklemme nach Fig. 7 und

Fig. 9

Einzelteile der Rohrkeilklemme in schaubildlicher Darstellung.

Show it:

Fig. 1

the cross section through a tube with this comprehensive clamping jaws,

Fig. 2

the longitudinal section AB through the device of FIG. 1,

Fig. 3

3 shows an enlarged illustration of a region of the longitudinal section AB,

Fig. 4

the enlarged plan view of a part of the insert with embedded needle-shaped parts,

Fig. 5

the arrangement of needle-shaped parts with an inclination to the radial direction,

Fig. 6

the enlarged representation of a longitudinal section of an insert with embedded granular particles,

Fig. 7

the cross section through a pipe wedge clamp with inserts with embedded needle-shaped parts,

Fig. 8

a longitudinal section through the wedge clamp according to Fig. 7 and

Fig. 9

Individual parts of the pipe wedge clamp in a diagram.

1, a pipe section 1 of a clamping jaw 2, which consists of a clamping body 3 and a jaw shell 4 for receiving an insert 5 made of an elastomeric material. The clamping body 3 shows hinge-like fastening tabs 3a between which the tabs of lever-like holding elements, not shown, engage, which are secured by inserting a bolt through the bores 6. The shell 4 forms together with the surface of the tube 1, the end rings 7 and longitudinal strips 8 a chamber for receiving the inserts 5.

The insert 5 made of elastomeric material contains, according to FIGS. 1 and 4, radially aligned needles 9, the radially outer ends of which end at a distance in front of the jaw shell 4. The elastomeric material 10 in this area therefore has the possibility of displacing laterally under high pressure in the event of unevenness of the parts to be screwed and to compensate for the unevenness. 5 needles 11 are embedded with an inclination to the radial direction. Their course shows a discontinuity 11a in the form of an inflection point in the radially outer region, which leads to a radially directed region. As a result, the needles are better able to move sideways, if this should be necessary due to the not completely uniform surfaces on which the insert lies. As a result, the needles are designed to be resilient. Metals based on iron and non-iron can be mentioned as suitable materials for the needles. Plastic needles of sufficient hardness are also conceivable. These can lead to a particularly gentle treatment of the surfaces to be captured when high torques are transmitted. With all rod-shaped parts, excessive deflection or kinking is prevented by the all-round pressure of the carrier material.

In the exemplary embodiment according to FIG. 6, the elastomeric material of the insert 5 contains granular particles 12, for example diamond dust grains. Other crystalline materials are suitable, such as quartz, glass, corundum, ceramics and the like.

The inserts 5 can together form a circumferential angle of almost 360 °, so that only slight, ie slit-shaped free spaces 13 are created which must be present to ensure a sufficient contact pressure. In connection with the large circumferential angle, the surface pressure can be determined by the length of the inserts, so that inserts can be manufactured, the surface pressure of which is appropriate for the respective pipe material.
7 to 9, the insert comprising the tube 20 is divided into three segments 21a to 21c. Each segment is positively fastened in a multi-part adapter 23a to 23c. The adapters 23a to 23c are positively connected to wedges 26a to 26c via dovetail-shaped grooves 24 and correspondingly designed springs 25.
End rings 27 and longitudinal strips 28 form chamber-shaped receiving spaces for the inserts 21 with their rigid shells 22 on the adapter elements 23. The deposits are thus secured against rotation as well as against displacement in the longitudinal direction.
In the assembled state, the wedges 26 lie with their outer lateral surfaces in a wedge-shaped opening 32 in a housing ring of the entire tubular wedge clamp. Due to the weight of the pipe string 30 in the direction of arrow 31, all the elements involved in the pipe wedge clamp slide into one another and hold the pipe string after loosening an elevator at the upper end of the pipe string without the outer jacket of the pipe string being damaged by cuts or notches in knife-like tools.

Claims (17)

1. A device for introducing translatory forces and/or torques into movable members, having a coating or intermediate layer of an elastomeric material disposed between the force transmitting parts and the movable members, characterized in that the elastomeric material is disposed in the form of inserts in clamping jaws of the device and acts as a support material for a plurality of particles embedded therein and having tips directed towards the bearing faces of the members to be clamped.
2. A device according to Claim 1, characterized in that needles (9, 11) whose engagement side ends extend at least as far as the internal periphery of the inserts are embedded in the support material.
3. A device according to Claim 2, characterized in that the needles (11) are disposed in the support material with an inclination differing from the radial direction.
4. A device according to Claim 2 or 3, characterized in that the needle contour has a point of discontinuity (11a).
5. A device according to Claims 2 to 4, characterized in that the ends of the needles on the clamping jaw side terminate in the clamping jaws at a distance in front of the bearing faces of the elastomeric inserts.
6. A device according to Claim 1, characterized in that the embedded particles are granular particles and consist of one of the following materials: diamond, glass, ceramics, corundum, quartz.
7. A device according to Claim 6, characterized in that the granular particles consist of a mixture of the following materials: diamond, glass, ceramics, corundum, quartz.
8. A device according to one of Claims 1, 6, 7, characterized in that the granular particles are of substantially identical size.
9. A device according to one of Claims 1, 6, 7, characterized in that the granular particles have different sizes.
10. A device according to one of Claims 1 to 9, characterized in that the inserts are glued into the clamping jaws.
11. A device according to one of Claims 1 to 10, characterized in that the inserts and clamping jaws are positively inter-connected by a profile which extends perpendicular to the direction of transmission of force.
12. A device according to one of Claims 1 to 11, characterized in that the inserts are disposed in chamber-shaped recesses in the clamping jaws.
13. A device according to one of Claims 1 to 12, characterized in that the clamping jaws with the inserts are constructed in shell shape to engage around annular members.
14. A device according to Claim 13, characterized in that the angle subtended by a clamping jaw with insert is substantially 180°.
15. A device according to Claim 13, characterized in that the insert (21) is disposed in a multi-part adaptor (23), and the adaptor parts are attached to wedges (26) of a tube wedge clamp for lowering and holding a pipe string (30).
16. A device according to Claim 15, characterized in that the adaptor parts (23a - 23b) are positively connected to the wedges.
17. A device according to one of Claims 13, 15, 16, characterized in that the adaptor parts with the inserts subtend an angle of substantially 120°.

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