HANDLE FOR A PNEUMATIC POWER TOOL

Abstract: A pneumatic power tool comprises a housing (10) with a pistol type handle (11), a motor located in the housing (10), a pressure air inlet passage (13) and an exhaust air passage (14) both extending through the handle (11) in substantially parallel with each other, and a manually operable throttle valve (12) located in the air inlet passage (13), wherein the handle (11) comprises a tubular stem (20) forming part of the air inlet passage (13) and a hollow grip element (30) which surrounds the stem (20) and defines together with the stem (20) a part of the exhaust passage (14), and the grip element (30) is detachably secured to the housing (10) by a clamping means (22-24, 28, 29). The grip element (30) comprises a heat insulating material and is interchangeable with at least one alternative grip element (30) of different size and/or shape.

Description: HANDLE FOR A PNEUMATIC POWER TOOL This invention relates to a pneumatic power tool of the type having a housing with a pistol type handle, a motor in the housing, a pressure air inlet passage and an exhaust air passage extending substantially in parallel to each other through the handle, and a manually operable throttle valve located in the air inlet passage. In this type of power tools, as for example the tool disclosed in GB 2 098 528, there is a problem to satisfy the demand for a good heat insulation in combination with an acceptable grip size of the handle. In a tool of the above type, the handle is formed in a heat conducting light metal alloy, and since the exhaust air passing through the handle is very cold due to a previous expansion in the -motor, the outer surface of the handle becomes uncomfortably cold for the operator. In order to solve this cold problem, an insulating layer of a suitable material has sometimes been applied on the outside of the handle. This adds to the grip size of the handle and makes the handling of the tool not only uncomfortable and tiresome but in some cases unsafe. Another problem concerned with the above type of power tools is that the grip size of the handle is not variable. This means that a comfortable handling of the tool is only available to those operators who has a certain hand size, whereas the handle is too thick for persons with smaller hands, like many female operators. but too slim for operator's with big hands. A solution to chis problem and also to the cold problem is shown in EP--A-481 947. In this publication there is described a penumatic power tool with a pistol type handle having a grip element which is easily excangeable for alternative grip elements of different sizes to suit different operators. The cold problem is solved in that exhaust air does not at all pass through the handle. Instead, this known tool has a specially designed housing for communicating inlet air as well as exhaust air between a top location on the housing and the motor. Apart from the fact that this known tool housing is more complicated and more expensive, the inlet and exhaust air passages are separated from the handle. This means that the most common and in most cases the most suitable air conduit connection and exhaust air outlet at the outer end of the handle is not possible in this prior art tool. According to the invention, there is provided a pneumatic power tool by which all of the above discussed problems are solved. The invention provides a pistol type power tool which comprises a handle which not only enables a good heat insulation and an adaptation of the grip portion size to the operator's individual needs but which retains the conventional and simple tool housing design as well as the most desirable air inlet and outlet location at the outer end of the handle. A preferred embodiment of the invention is described below with reference to the accompanying drawings. On the drawings: Fig 1 shows a side view, partly in section, of a power tool according to the invention. Fig 2 shows, on a larger scale, a fraction of the power tool in Fig 1. Fig 3 shows a cross section along line III-III in Fig 2. The power tool shown on the drawings comprises a housing 10 with a pistol type handle 11 and a throttle valve 12. Within the housing there is located a pneumatic motor (not shown) which is supplied with motive pressure air through an inlet passage 13 and which exhausts air through an exhaust passage 14. The inlet and exhaust passages 13, 14 extend substantially in parallel to each other through the handle 11. The throttle valve 12, which is manually operable by a push button 16, forms part of the inlet passage 13. The throttle valve 12 also traverses the exhaust passage 14 and comprises an outer sleeve 17 with two lateral openings 18, 19 which form part of the exhaust passage 14. The handle 11 comprises a central tubular stem 20 which forms a part of the inlet passage 13 and which is formed by a protrusion 21 from the housing 10 and two tube sections 22, 23 interconnected by a thread joint 24 and secured to the housing protrusion 21 by means of another thread connection 25. The outer tube section 23 is formed with a threaded socket 27 for connection of a pressure air supply conduit. The inner end of the outer tube section 23 forms an annular shouldar 28 which engages an oppositely facing shoulder 29 on a hollow grip element 30 to firmly secure the latter to the tool housing 10. The grip element 30, which is supported on a neck portion 31 on the housing 10, surrounds the tubular stem 20 and defines together with the latter a part of the exhaust passage 14. The shoulder 29 is formed by an inner ring portion 32 of the grip element 30 and is supported on one side by a stay member 33. A tubular outlet diffusor 34 is supported coaxially around the outer tube section 23 and is axially locked by a lock ring 35 mounted in a circumferential groove 36 in the socket 27. However, the duffusor 33, which on one side is formed with a number of outlet slots 37, is rotatable to enable change of outlet flow direction. The grip element 30, which is easily detachable from the tool housing 10 after removal of the outer tube section 23, is moulded in a heat insulating resinous material in order to protect the operator from the cold of the exhasut air. The grip element 30 is not only easily detachable from the housing 10 it is also exchangeable for alternatively shaped grip elements for adaptation of the grip size and shape to different operator's needs. In other words, the grip element 30 is one of two or more interchangeable grip elements providing different sizes and shapes of the handle grip.

Claims: Claims. 1 A pneumatic power tool comprising a housing (10) with a pistol type handle (11), a motor located in said housing (10), a pressure air inlet passage (13) and an exhaust air passage (14) extending substantially in parallel to each other through said handle (11), and a manually operable throttle valve (12) located in said air inlet passage (13), c h a r a c t e r i z e d i n that said handle (11) comprises a tubular stem (20) forming a part of said air inlet passage (13), and a separate hollow grip element (30) surrounding at least partly said stem (20) and defining together with said stem (20) a part of said exhaust air passage (14), said grip element (30) is detachably secured to said housing (10) by a clamping means (22-24, 28, 29) on said stem (20) . 2. Power tool according to claim 1, wherein said stem comprises an inner section (22) rigidly connected to said housing (10) and an outer section (23), and said clamping means (22-24, 28, 29) comprises a thread connection (24) for securing said outer stem section (23) to said inner stem section (22) as well as interengageable shoulders (28, 29) on said outer stem section (23) and said grip element (30) 3. Power tool according to claim 1 or 2, wherein said grip elem nt (30) comprises a heat insulating material. 4. Power tool according to claim 3, wherein said grip element (30) is moulded from a resinous material. 5. Power tool according to claim 1, wherein said grip element (30) is one of two or more interchangeable grip elements providing different grip sizes and/or shapes.

Inventors: RAHM ERIK ROLAND, RAHM, ERIK, ROLAND
Applicants: ATLAS COPCO TOOLS AB, RAHM ERIK ROLAND, RAHM, ERIK, ROLAND
Application year: 1995
Main classification: B25F5
IPC codes: B23B45, B25B21, B25B23, B25F5, F16K1, F16K31