The invention relates to a portable power tool having a housing, a motor, an output shaft, and a power transmission coupling the motor to the output shaft. In particular, the invention concerns a power tool of the above type, wherein the housing comprises a main part supporting the motor, and a detachable forward part supporting the output shaft.

In a known power tool of the above type the forward part of the housing is attached to the main part of the housing via a flange connection including a number of screws joints. This flange type connection between the two housing parts requires a rather wide housing which is undesirable since it has a negative influence both on the weight and the outer dimensions of the tool . A wide tool housing is disadvantageous in when using the tool in difficult-to-reach working positions. Moreover, the flange and screw joint type of housing part connection is undesirable also in that it requires a certain working time to remove and remount a number of screws to get access to the inside of the housing at tool service operations.

It is an object of the invention to provide a power tool wherein the above mentioned problems are avoided.

It is a further object of the invention to provide an improved power tool comprising a housing with a main part and a

detachable forward part, wherein the above mentioned problems are avoided in that a forward part of the tool housing is attached to a main part of the housing via a slim and easily operable connection device.

Other objects and advantages of the invention will appear from the following specification and claims.

A preferred embodiment is below described in detail with reference to the accompanying drawing.

In the drawings Fig. 1 shows a perspective front view of a power tool according to the invention.

Fig. 2 shows an exploded view of the power tool in Fig. 1.

Fig. 3 shows, partly in section, an exploded side view of the power tool in Fig. 1.

The power tool illustrated in the drawings is an electric power wrench of the impulse type comprising a housing 10 divided into a main part A and forward part B, wherein the main part A of the housing 10 supports a motor and comprises a handle 11 with a trigger 12 for power control. Power is supplied by a battery unit attached to the handle 11 via contact bracket 13. The forward housing part B supports an output shaft 14 and a power transmission in the form of a pulse unit 15 coupling the motor to the output shaft 14. At its rear end the forward housing part B has a transverse contact surface 16 intended to abut against a mating transverse surface 17 on the main housing part A as the two housing parts are joined together. At its front end the forward housing part B has a transverse end wall 18 which is formed with a socket portion for supporting an output shaft bearing 19.

The pulse unit 15 is of a previously known type and does not form a part of the invention, and therefore it is not described in further detail. See for instance patent publication WO

91/14541.

The forward housing part B is arranged to be connected to the main housing part A by means of a connection device which comprises a substantially rotation symmetric retaining sleeve 22 located inside the forward housing part B and extending

throughout the length of the latter in a substantial coaxial relationship with the output shaft 14. The retaining sleeve 22 has a front end 23 and a rear end 24, wherein the rear end 24 is provided with an external mounting thread 25 for engagement with a mating internal mounting thread 26 on the main housing part A. This thread connection between the retaining sleeve 22 and the main housing part A is intended to lock axially the retaining sleeve 22 relative to the main housing part A, while providing an adjustability of the angular position of the retaining sleeve 22.

At its front end 23 the retaining sleeve 22 is formed with three identical part-cylindrical axial extensions 28 which are located at equal angular intervals over the periphery of the retaining sleeve 22. These extensions 28 are provided with a common external thread 27 and are intended to extend out through three arc-shaped apertures 33 in the end wall 18 as the forward housing part B is connected to the main housing part A. The apertures 33 are located at a common radius radially outside the bearing 19 and distributed at equal angular intervals so as to coincide with the extensions 28 at mounting of the forward housing part B. A nut 38 is intended to engage the thread 27 on the extensions 28 to apply an axial thrust force onto the forward housing part B to thereby clamp the latter axially against the main housing part A.

At its rear end the forward housing part B has an irregular outer shape accomplished by a radially extending portion 40 intended to cooperate with a mating portion 41 on the main housing part A, which means that the forward housing part B has to be mounted in a positively defined angular position relative to the main housing part A. This also means that the angular position of the retaining sleeve 22 has to be adapted to that position to make the extension 28 coincide with apertures 33 in the end wall 18, and thanks to the movability of the thread connection 24, 25 between the retaining sleeve 22 and the main housing part A the angular position of the retaining sleeve 22 may be readably adjusted.

Connection of the forward housing part B to the main housing part A is started in that the retaining sleeve 22 is threaded into the main housing part A until a full stop is reached. Then the forward housing part B is to be put in place with its rear end surface 16 facing the surface 17 of the main housing part A, but before that the angular position of the retaining sleeve 22 has to be adjusted by a reverse movement such that the

extensions 28 will coincide with the apertures 33 in the end wall 18. When the angular position of the retaining sleeve 22 is correctly adjusted the forward housing part B may be put in its proper place with the extensions 28 protruding through the apertures 33. Then, the nut 38 will be entered onto the threaded extensions 28 and tightened to clamp the forward housing part B to the main housing part A. The bearing 19, which has been pre- mounted in the forward housing part B, is slid onto the output shaft 14 during mounting of the forward housing part B.

In relation to previously known tool housing designs the tool housing according to the invention includes a single nut for securing the housing parts to each other which means a readily operable connection joint and slimmer outer dimensions of the tool .

It is to be noted that the invention is not limited to the example shown and described but could by freely varied within the scope of the claims. For instance, the retaining sleeve 22 does not have to be axially locked to the main housing part A via a thread connection. In alternative embodiments of the invention the retaining sleeve 22 may be axially locked to the main housing part A via other types of adjustable lock devices or may even be formed as a rigid extension of the main housing part A. In the latter case the angular position of the retaining sleeve 22 is fixed and guarantees that the extensions 28 will coincide with the apertures 33 in the forward housing part B at mounting of the latter.