EP0189600B1 - Apparatus for producing thread connections between pipes - Google Patents

Abstract

An apparatus for making and breaking connections between screw threaded tubular members comprises a jaw carrier. A movable jaw support is pivotally mounted to one end of the jaw carrier while a fixed jaw support is mounted on the other end of the jaw carrier. The fixed jaw support and the jaw carrier each carry a jaw. The centers of the jaws subtend an angle of 90 DEG . The movable jaw support is provided with a jaw which can be advanced towards the other jaws to grip a pipe by the action of a cam on a cam engaging roller mounted on the movable jaw support. The fixed jaw support and the movable jaw support can be interchanged to break and make joints as required.

Description

The invention relates to a device for producing threaded connections between tubular bodies, consisting of a housing with a continuous axial opening, a radial cutout adapted to the outer diameter of the tube and a toothed ring which is rotatably arranged in the housing by means of a drive device and which is provided with a corresponding radial cutout and overrun cams carries with overrun curves, which are associated with an articulated clamping jaw with a gripping knife and at least one further rigid clamping jaw with a gripping knife as a counter-knife on a lever which increases the contact pressure.

According to DE-B-3 234 027, a device for countering and breaking threaded connections between pipe bodies of pipe and drill strings and drilling tools for deep drilling uses a rotatable and a non-rotatable chuck, which together define a device main axis, to accommodate one of two pipe bodies used with mutually facing end thread areas, the one chuck being mounted in a bearing block which is fixedly supported on one end of a device frame and the other chuck is arranged on a support block. This device is only stationary and cannot be used on a derrick.

US-A-4 297 922 shows a device for producing threaded connections between tubular bodies, which consists of a housing with an axial opening and a radial cutout adapted to the outer diameter of the tube. A rotatable gear rim with a corresponding radial cut-out is located within the housing. An articulated clamping jaw with a gripping knife is arranged on a lever element which increases the contact pressure. The movable clamping jaw can be exchanged for a rigid clamping jaw by repositioning, in order to be able to make a screwing process reversible. However, this device is not suitable for the transmission of high torques and thus not for countering and breaking drill rods, because the gripping knives are fastened to simple jaw carriers, so that large forces cannot be transmitted.

For screwing in particular casing pipes for boreholes, it is known from DE-B-2 726 472 to use a pipe wrench, the housing of which likewise has a radial cutout adapted to the outside diameter of the pipe. With the help of a drive device, a toothed ring is rotatably arranged in the housing, which has a corresponding radial cutout and bears cams with run-up curves of different pitch ranges. This device is suitable for screwing pipes that are inserted into a deep hole. The tubes have a diameter that is almost uniform over their entire length, which is no problem when producing screw connections with gripping knives that are matched to the tube diameter. The screwing of drill pipes, however, requires higher torques with smaller diameters of the pipes of the drill pipe. The drill pipe is subject to considerable wear from the rock. Therefore the pipe diameters within the string of a drill pipe are very different. The screwing device must therefore be able to perform its function even with very different pipe diameters. The use of open pliers, as described in DE-B-2 726 472, has so far not been suitable for screwing down drill rods due to the considerable torques required, in particular for countering and breaking.

The invention is based on the object of also creating a hand-guided, open pliers for screwing on drill rods for use on the drilling rig, with which the necessary very high torques, which must be several times higher than in the previously known constructions, can be applied despite the light version of the pliers. The solution according to the invention is characterized in that the rigid gripping knife attached to the articulated clamping jaws is assigned two rigid gripping knives as counter-holding knives, with the articulated clamping jaws carrying the gripping knife and the rigid gripping knife carrying the neighboring jaw seen in the direction of rotation for reversibility of the clamping movement in a release movement The jaws are interchangeable by repositioning and the movable jaw is designed as a one-armed force-boosting lever with a pressure roller that can be actuated by the run-up curve, and the gripping knives and jaws are fastened to a solid crescent-shaped jaw carrier and that the movable gripping knife is convex. Since the movable gripping knife is convex, each drill pipe is securely gripped at three points in connection with two rigid gripping knives. The pipe detection system at three points ensures the processing of drill pipes with significantly different diameters. In order to prevent the overrun cam from slipping past the pressure roller of the movable clamping jaw if the drill pipe is worn too far, housing-fixed stops are provided for the overrun cams carrying the overrun curves. For this purpose, stop bolts are used, which are assigned to the overrun cams so that each cam can lay its rear surface against a stop bolt as soon as the pressure roller of the movable clamping jaw has reached the top end of an overrun curve.

To break a screw connection, the movable one is against the opposite one rigid jaw replaced. Both jaws as well as the third gripping knife are carried by a sickle-shaped solid jaw carrier known per se, which is connected to the rotor disks. After changing the position of the movable jaw with the rigid, the direction of rotation of the ring gear can be reversed, so that when the pipe section in question is securely gripped again, it can be rotated counter to its screwing direction and its connection with the adjacent rod section can be broken.

Advantageously, the device according to the invention is also suitable for the actual screwing process, for "spinning". With one and the same device, the screwing rotations can be carried out in addition to countering and in the opposite direction from breaking to complete loosening. This means that a device is provided whose properties, namely low mass, open system and the ability not only to counter or break a screw connection, but also to carry out the entire screw movement, allow use on a derrick and thus a considerable saving of time.

Further features which advantageously further develop the subject matter of the invention are specified in the subclaims.

In the drawing, an embodiment of the invention is shown schematically and explained below.

• Fig. 1 die Draufsicht auf den Rotorkranz und den Backenträger mit zugehörigen Greifmessern bei einer abgenommenen Rotorscheibe,
• Fig. 2 den Schnitt A - B durch die Figur 1,
• Fig. 3 den Schnitt C - D durch die Figur 1,
• Fig. 4 den Backenträger mit Klemmbacken in größerem Maßstab und
• Fig. 5 den Schnitt E - F durch die Figur 4. Innerhalb des Rotorkranzes 1 mit der Verzahnung 2 ist ein sichelförmiger Klemmbackenträger 3 angeordnet. Der Backenträger 3 trägt drei Greifmesser 4, 5 und 6, von welchen lediglich das Messer 4 drehbeweglich in einer beweglich gelagerten Klemmbacke 7 angeordnet ist. Die Klemmbacke 7 ist in Form eines einarmigen, die Klemmkraft verstärkenden Hebels ausgebildet. Sie ist mit einem Schwenkbolzen 8 am Backenträger 3 befestigt. Die radiale Einwärtsbewegung der Klemmbacke 7 wird mit Hilfe einer Druckrolle 9 erzielt. Sie läuft bei einer Drehung des Rotorkranzes 1 in Richtung des Pfeiles 10 auf die Auflaufkurve 11 des Auflaufnockens 12 auf. Die Rückstellbewegung wird über eine Rückstellfeder 13 erzielt, die am Bolzen 14 der beweglichen Klemmbacke 7 angreift und mit ihrem entgegengesetzten Ende an einer Rotorscheibe befestigt ist. Zur besseren Übersichtlichkeit der Zeichnung ist die Darstellung des Gehäuses der Gesamtvorrichtung weggelassen worden.

Show it:

• 1 is a top view of the rotor ring and the jaw carrier with associated gripping knives when the rotor disk is removed,
• 2 shows the section A - B through Figure 1,
• 3 shows the section C - D through Figure 1,
• Fig. 4 shows the jaw carrier with jaws on a larger scale
• 5 shows the section E-F through FIG. 4. A crescent-shaped jaw support 3 is arranged within the rotor ring 1 with the toothing 2. The jaw carrier 3 carries three gripping knives 4, 5 and 6, of which only the knife 4 is rotatably arranged in a movably mounted clamping jaw 7. The clamping jaw 7 is designed in the form of a one-armed lever which increases the clamping force. It is attached to the jaw support 3 with a pivot pin 8. The radial inward movement of the jaw 7 is achieved with the help of a pressure roller 9. When the rotor ring 1 rotates in the direction of arrow 10, it runs onto the run-up curve 11 of the run-up cam 12. The restoring movement is achieved by means of a restoring spring 13 which engages the bolt 14 of the movable clamping jaw 7 and is fastened with its opposite end to a rotor disk. For a better clarity of the drawing, the illustration of the housing of the overall device has been omitted.

The rigid gripping knife 5 is arranged on the end of the crescent-shaped jaw support 3 opposite the movable gripping knife 4. It is inserted into a fixed jaw 15, which in turn is firmly connected to the rotor disks 18 and 19 via a bolt 17. A fixed stop 15 includes a return stop 20 which is connected to the rigid jaw by pins 21 in a form-fitting manner. In the example shown, the return stop limits the rotation of the rotor ring 1 in a direction of rotation which is directed in the opposite direction to the arrow 10. In the case of such a reverse rotation, the return stop can rest against the run-up curve 22 of the second run-up cam 23 or, after having been plugged into the position of the movable clamping jaw, against the run-up curve 11 and turn the system of the rotor ring with rotor disks back into the starting position.

The third, likewise rigid gripping jaw 6 is fastened in the middle of the jaw carrier 3. This results in a force attack at three points on a drill pipe. Due to the movable mounting of the convex-shaped gripping knife 4 in the movable clamping jaw 7 designed as a one-armed lever, drill rods of different diameters can be gripped, screwed and countered or a screw connection broken with sufficient security. The positions of a 5 7/8 "and a 6 1/2" drill pipe 31 and 30 are indicated in broken lines. In the example shown, the 5 7/8 "tube 31 is the smallest size that can be detected by the device. The pressure roller 9 is just being caught by the run-up curve 11 with its radially inner end. To prevent the run-up cam in such a case with its run-up curve slipping past the pressure roller, stop bolts 24 and, in the opposite direction of rotation, 25 serve. Against these stop bolts, the run-up cams 12 and 23 can rest with their rear ends. The rotor ring 1 is bordered on both sides by slide guide rings 26 and 27, with which it can slide in circumferential grooves 28 and 29 of the rotor disks 18 and 19.

Before the screwing process begins, the radial cutouts of the housing, rotor disks and rotor ring are brought into line by rotating the rotor ring. The suspended device can then be pivoted by hand onto a pipe until the rigid gripping knives 5 and 6 come into contact. The two rigid knives are offset by 90 ° to each other and thus ensure that the device is centered on the pipe or drill pipe. Then the rotor ring 1 is rotated in the direction of the arrow 10. As a result, the pressure roller 9 of the movable clamping jaw 7 runs onto the run-up curve 11 of the run-up cam 12 and pivots the gripping knife 4 against the drill rod 31. After reaching the predetermined clamping value, the is necessary to transfer the counter or breaking torque to a screw connection, the actual screwing or unscrewing process begins.

In a plan view according to FIG. 1, the movement arrow 10 shows the direction of rotation for breaking a screw connection with subsequent unscrewing process. In contrast, if the device is to produce a screw connection, the movable clamping jaw 7 and the fixed clamping jaw 15 are exchanged for one another beforehand. The bolt 8b thus becomes the pivot bolt for the jaws 7, while the previous pivot bolt 8a engages through the fixed jaws 15. The return springs 13 each ensure that after a corresponding return rotation of the rotor ring, the contact pressure of the gripping knife 4 is completely removed and the clamping jaws 7 is pivoted radially outwards.

The arrangement of the convex gripping knife 4 on the jaw 7 is selected so that the clamping force is increased by the position of the jaw. The position of the pressure roller compensates for the loss of tension force that the system experiences when it works at the maximum allowable dimension of the drill pipe connection. In this case, the lever arm between the pivot pin 8a and the pressure roller 9 becomes larger; the effective lever arm for increasing the clamping force is reduced. The force application point on the linkage to be screwed lies between the center of gravity of the clamping jaw and the center of the entire system. As a result, when the rotary movement is initiated after the gripping knife 4 has gripped the drill pipe 31, an inward pressing force occurs, which brings about a secure gripping of the gripping knife. A clamping reinforcement is created. The pitch angle of 30 ° -60 °, preferably 45 °, of the run-up curves results in an almost tangentially directed load on the rotor ring and thus prevents its ends from widening in the region of the radial cutout.

Due to its low mass, the device according to the invention can be guided by hand and is nevertheless able to apply the highest torques which are necessary for countering or breaking the screw connections of drill rods. The ratio of the maximum torques to the weight of the device is much larger than in the previously known designs. The three-point clamping, in particular in connection with the arrangement of the rigid gripping knives at an angle of 90 ° to one another, leads to an optimal clamping with minimal loss of time. However, time wasted in drilling operations should be avoided as much as possible due to the high costs involved.

Claims (8)

1. Apparatus for producing thread connections between pipes, consisting of a housing with an axial opening passing through it, a radial cutout proportioned to the outside diameter of the pipe, and a toothed ring (1) which is arranged in the housing and can be rotated by means of a driving device and which is provided with a corresponding radial cutout and carries stopping cams (12, 23) having lifting flanks (11, 22), to which there are assigned, on a lever which amplifies the contact pressure, a flexibly mounted clamping jaw (7) with a gripping blade (4), and at least one further, rigid clamping jaw (15) with a gripping blade (5, 6) as a counter-holding blade, characterised in that, assigned to the gripping blade (4) which is attached to the flexibly arranged clamping jaw (7), there are two rigid gripping blades (5, 6) as counter-holding blades, whereby, to make the tensioning movement reversible, so that it can become a releasing movement, the flexible clamping jaw (7) with the gripping blade (4), and the clamping jaw (15) carrying the rigid gripping blade (5) which is adjacent relative to the direction of rotation, can be interchanged by means of rearrangement, and whereby the moveable clamping jaw (7) is formed as a single- armed, power amplifying lever, with a pressure roller (9) which can be actuated by the lifting flank, and the gripping blades and clamping jaws are attached to a solid, sickle-shaped jaw carrier (3), and in that the moveable gripping blade (4) has a convex form.

2. Apparatus according to claim 1, characterised in that the rigid gripping blades (5, 6) are arranged so that they are displaced at 90° to each other.

3. Apparatus according to one or more of Claims 1 to 3, characterised in that a stop pin (24, 25), which is fixed to the housing, is assigned to each stopping cam (12, 23).

4. Apparatus according to claim 3, characterised in that the ends of the stopping cams (12, 23) which are opposite the lifting flanks (11, 22), serve as stop surfaces for the stop pins.

5. Apparatus according to one or more of claims 1 to 5, characterised in that the toothed ring (1) is provided on both sides with sliding guidance rings (26, 27) which grip into solid rotor discs (18, 19).

6. Apparatus according to one or more of the claims 1 to 7, characterised in that the moveable clamping jaw (7) is constantly acted upon by the force of a restoring spring (13) which is directed radially outward.

7. Apparatus according to one or more of claims 1 to 8, characterised in that the fixed jaw (15) is supplied with a return stop (20) which is assigned to the lifting flank (22).

8. Apparatus according to one or more of claims 1 to 9, characterised in that the angles of inclination of the lifting flanks come to 30^{: -} 60^:.

Images