MECHANISED WRENCH DEVICE

There is provided a mechanised wrench device. More particularly it concerns a mechanised wrench device comprising an about a central axis driven turntable with a central opening there through, and where the turntable is supported in a framed structure .

In rock drilling where holes are drilled for example for leading water to a power station or to a water distribution plant, joinable lengths of pipe are often used to construct a drill string.

Pipe lengths of this type are often provided with wrench recesses at their end portions. Suitable wrenches may be placed in the wrench recesses to be able to torque up and undo a pipe connection.

As pipe strings of this type have been getting larger dimensions, and drilling is carried out from a lower height level and upwards, the manual connection work constitutes heavy and time consuming work.

The object of the invention is to remedy or reduce at least one of prior art drawbacks .

The object is achieved according to the invention by the features stated in the description below and in the following claims .

There is provided a mechanised wrench device comprising an about a central axis driven turntable with a central opening there through where the turntable is supported in a framed structure, and where the mechanised wrench device is characterised in that a wrench body running in a wrench guide on the turntable is radially displaceable between an active position wherein the wrench body is near the central axis, and a passive position wherein the wrench body is displaced away from the central axis.

The wrench body may complementary fit in a wrench slot in a pipe.

When the wrench body is in the active position and for example in engagement with the pipe, the turntable and thereby the wrench body is rotated about the central axis in a desired direction to be able to torque up or undo a pipe connection.

The framed structure may be axially displaceable in parallel with the central axis. The pipe may thereby, after having been engaged by the wrench body, be displaced axially relative to a pipe string to which the pipe is to be connected or from which' the pipe is to be disconnected. The axial displacement also makes possible adaptation of the axial position of the mechanised wrench relative to the wrench recess in the pipe .

A motor may drive the turntable via a gear meshing with a gear rim on the turntable. A hydraulic motor is suitable, as the torque for torqueing up a pipe connection may be relatively simply controlled. However an electric motor with the necessary gears may in some cases be preferable.

A hydraulic cylinder may be connected to the wrench body and be arranged to be able to displace the wrench body in its

wrench guide between its active and passive positions. The hydraulic cylinder also ensures that the wrench body is held in engagement with the pipe during the screwing/unscrewing operation.

When the wrench body is pulled back to its passive position, the pipe may be freely displaced through the opening therethrough .

In the following is described an example of a preferred embodiment which is illustrated in the accompanying drawings, wherein:

Fig. 1 shows a mechanised wrench in perspective; and

Fig. 2 shows the mechanised wrench of Fig. 1 in perspective, where a length of pipe is in the process of being connected to a pipe string.

In the drawings the reference numeral 1 indicates a mechanised wrench comprising a turntable 2 where the turntable 2 is rotatably supported about a central axis in a framed structure 6.

The turntable 2 is provided with an external gear rim 8 meshing with two gears 10 where the gears 10 are connected to one motor 12 each.

A wrench body 14 is radially displaceable in a wrench guide 16 on the turntable 2. The wrench body 14 is displaceable by means of the hydraulic cylinders 18 between an inactive retracted position, see Fig. 1, and a central position, see Fig. 2, where the wrench opening 20 of the wrench body 14 is in engagement with a wrench recess 22 on a pipe 24.

In this preferred exemplary embodiment is the framed structure 6 arranged on guide bearings 25 which are

displaceable on axial guides 26, where the axial guides 26 are connected to a not shown base by means of guide supports 28.

The framed structure 6 may be displaced by means of a not shown hydraulic cylinder. Moreover are the necessary pipes, hoses, cables and guides not shown.

When a pipe 24 is to be mounted in a pipe string 30, the pipe 24 is displaced into a central opening 32 running through the turntable 2. The hydraulic cylinders 18 displace the wrench body 14 forward toward the pipe 24, as the wrench opening 20 grips the wrench notches 22 in the pipe 24.

The pipe 24 is then displaced by means of the guide bearings 24 and the axial guides 26 toward the pipe string 30, whereafter the motors 12 start and rotate the turntable 2 and the wrench body 14 with the pipe 24 about the central axis 4, whereby the pipe 24 is screwed into the pipe string 30 with a defined torque .

The wrench body 14 is subsequently withdrawn from the pipe 24, which is thereby free to be displaced through the opening 32.

Unscrewing of a pipe 24 from the pipe string 30 is done in the opposite order.