Electric power tool with swivelled cable connection

An electric power tool having a housing, a motor, a jack for receiving a connection plug of an electric cable, and a swivel unit mounted on the housing and carrying the jack, wherein the swivel unit includes a first head mounted on the housing for rotation about a first axis, and a second head mounted on the first head for rotation about a second axis. The first and second axes form an angle between them, and provide for freedom of rotation of the jack, thereby providing for positioning of the jack and routing of a connected cable in desired directions relative to the housing.

This application is a U.S. National Phase Application under 35 USC 371 of International Application PCT/SE2007/000257 filed Mar. 16, 2007.

FIELD OF THE INVENTION

The invention relates to an electric power tool having a cable connection in the form of a jack for receiving a plug of an electric cable, and a swivel unit for positioning the jack in different directions to improve cable routing and tool handling.

BACKGROUND OF THE INVENTION

A problem concerned with today's power tools of this type is that the possible ways of positioning the jack and routing the cable in the vicinity of the tool are still limited. Accordingly, there is still a problem not only to obtain a comfortable handling of the tool but to get a well protected routing of the cable in different tool operating positions. This is a particular problem in multiple tool arrangements where two or more power tools are operated together.

SUMMARY OF THE INVENTION

The main object of the invention is to create a power tool with an improved cable connection arrangement where the above identified problem is solved.

A preferred embodiment of the invention is described below with reference to the accompanying drawing.

DETAILED DESCRIPTION

The power nutrunner shown inFIG. 1comprises a tubular housing10, an electric motor11located in the housing10, a reduction gearing12with torque and angle sensing means (not illustrated in detail), and a front end piece13supporting an output shaft15.

At its rear end the housing10supports a connection jack16for receiving a multi-connector plug of a multi-core cable (not shown), and a swivel unit17is arranged to connect the jack16to the housing10. The swivel unit17, which will be described in further detail below, provides for routing electric conductors between the jack16and the nutrunner housing10. These conductors include coarse power supply conductors connected to the motor11, and fine conductors for communicating signals between the torque and angle sensing means at the front of the housing10and the jack16. These fine conductors are routed from the rear end of the housing10to the front thereof via an external sleeve18extending between a forward cap19and a rear socket20.

According to one aspect of the present invention, an electric power tool includes a housing, a motor, a jack for receiving a connection plug of an electric cable, and a swivel unit for carrying the jack and which is mounted at a rear end of the housing and arranged to provide for freedom of positioning the jack in different angular directions relative to the housing. The swivel unit has a first head mounted on the housing for rotation about a first axis, and a second head carrying the jack and being mounted on the first head for rotation about a second axis, the second axis forming an angle relative to the first axis, whereby the swivel unit provides freedom of rotation of the jack about two axes of rotation disposed at an angle relative to each other.

The swivel unit17comprises a first head24rotatably mounted on the rear end of the housing10for rotation about an axis of rotation A, and a second head25rotatably mounted on the first head24for rotation about an axis of rotation B. As illustrated inFIG. 3, the axes of rotation A and B are disposed at an angle α relative to each other, and although the cable connection jack16is rigidly mounted on the second head25its movability is universal relative to the housing10.

The angle α between the rotation axes A and B is less than 90 degrees and provides for an inclined disposition of the rotation axis B relative to the rotation axis A, such that the jack16extends in an acute angle β relative to the axis A when oriented in a plane common to both rotation axes A and B. SeeFIG. 2.

The first head24is rotatively supported on a coaxial annular neck portion26of the tubular housing10, whereas the second head25is rotatively supported on a tubular flange27on the first head24via an intermediate sleeve28. Inside the neck portion26there is provided a rotatable thrust sleeve30which is formed with a rearwardly extending ear31for engagement with a lock spindle32. The latter extends laterally from the first head24and axially through the second head25to be engaged by a nut element33. A washer34beneath the nut element33engages the outside of the head25. By its engagement with the lock spindle32the thrust sleeve30is co-rotating with the first head24. The thrust sleeve30is axially locked by means of a lock ring35.

The first head24is rotatable relative to the housing10over a rotation range of just less than 360 degrees. This rotation range is determined by a radial pin38secured to the thrust sleeve30and an axial pin39secured to the housing10. The second head25is rotatable over a rotation range exceeding 360 degrees. This is obtained in that the intermediate sleeve28is formed with an inner annular flange40, and a stop pin41, which is secured to the flange40and protruding from the flange40in both directions, is arranged to co-operate with non-illustrated abutments on both the first head24and the second head25. Since the second head25is rotatable relative to the intermediate sleeve28over a rotation range of little less than 360 degrees and the sleeve28is rotatable relative to the first head24over a certain minor angle the total rotation range for the second head25is somewhat more than 360 degrees relative to the first head24.

In order to put the cable connection jack16in a position suitable for a particular nutrunner operating position and/or a certain arrangement with one or more other nutrunners the nut element33is loosened, and the jack16is rotated about the rotation axes A and B of the first and second heads24,25until the desired position is obtained. Then, the nut element33is tightened against the washer34, whereby the second head25is clamped against the first head24via the intermediate sleeve28such that a friction lock is obtained between both between the head25and the sleeve28and between the sleeve28and the first head24. Simultaneously, the lock spindle32applies a tension force on the ear31of the thrust sleeve30, whereby laterally directed force is obtained on the thrust sleeve30and as a result a counter directed lateral force is generated on the first head24. This means that a friction lock is obtained between the first head24and the outside surface of the neck portion26of the housing10as well as between the thrust sleeve30and the inside surface of the neck portion26. Accordingly, by tightening the nut element33and creating a tension force in the lock spindle32both heads24,25are frictionally locked against rotation, and the jack16is arrested in a desired position.

The swivel unit according to the invention, including the two rotatable heads24,25and the common lock arrangement with the lock spindle32and nut element33, is advantageous in that it provides a universal movability and freedom of rotation of the cable connecting jack16and a very simple and easy to handle lock mechanism to arrest the jack16in desired positions. This also means that the routing of the cable and handling of the nutrunner is facilitated, thereby gaining the productivity of the tool.