GB2153735A

GB2153735A - Handle for drilling machines and/or hammer drills

Info

Publication number: GB2153735A
Application number: GB08500710A
Authority: GB
Inventors: Karl Wanner
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1984-02-11
Filing date: 1985-01-11
Publication date: 1985-08-29
Also published as: DE3404962A1; GB8500710D0; CH666206A5; GB2153735B; DE3404962C2

Abstract

A handle for drilling machines and/or hammer drills is proposed, wherein a grip piece (7) oriented at an angle to the axis of the toolholder (3) is constructed so that it is at least as long as two hand widths and can be grasped with both hands by the user of the machine. The grip piece (7) is connected to the machine housing (2) via a bar (8) at such a point that one of the holding hands can grasp the grip piece (7) approximately in the prolongation or the axis (6) of the toolholder (3). Therefore one hand is located at the ideal point for the transmission of the feed forces to the machine, and hence to the drill, whereas the effect of torques which occur can be intercepted with the other hand without any auxiliary grip being required for this purpose. By the arrangement of at least one further bar (9 and/or 10) between grip piece (7) and housing (2), a particularly secure gripping construction of the handle (4) is obtained. <IMAGE>

Description

SPECIFICATION Handle for drilling machines and/or hammer drills The invention starts from a handle according to the generic type of the main Claim. It is known to construct such handles in the form of pistol grips, which the person operating the machine can grasp with one hand. He normally braces the machine in the region of its housing with the other hand, or else he grasps round the first hand with the second one, after the former has gripped the handle. In the absence of other possibilities, the operator has to endeavour to achieve a comparatively secure guidance of the machine in this manner. So-called spade grips are also known, which exhibit a reachthrough aperture for one of the operator's hands, surrounded in frame shape by two bars, the actual grip piece and the housing rear wall.Although such spade grips improve the security of grip when using the machine, compared to the pistol grips previously mentioned, nevertheless both types of grip have the disadvantage that it is extremely difficult for the operator, using such handles, to intercept the effect of the torques, frequently substantial, caused by the drilling drive, and thereby to control the machine correctly.

In order to improve this situation, it is known to attach special auxiliary grips to the machine housing, generally in the proximity of the toolholder, which are grasped by the operator with his second hand. Because these auxiliary grips constitute a lever arm of corresponding length oriented trans tersely to the tool axis, although they are suitable for controlling the machine, which is influenced by the torque acting during drilling, better than solely by the handle constructed on the machine itself, nevertheless this is an auxiliary means which is required additionally because the actual handle cannot ade quatelyfulfil its intended purpose.

A spade handle for hammer drills is indeed known, the grip piece of which, which is grasped by the holding hand, has a stub-shaped lug projecting downwards beyond the bar leading to the machine housing. This can be grasped by a part of the second hand. However, in this case the remaining part of the second hand grasps the connecting cable protruding out of the lug, or a cable bushing arranged in this region, whereby the danger of the connecting cable being forced off exists.

Advantages of the invention Compared to the above, the handle according to the invention with the characterising features of the main Claim has the advantage that it permits the machine to be guided and manipulated reliably without the use of auxiliary handle means, even when the machine is affected by an increased torque during operation. Holding the machine steady with the second hand by the part of the connecting lead passing into the handle, which is frequently done unconsciously during the drilling operation, and the resulting danger of forcing off the connecting lead, is totally eliminated. The possibility of grasping the handle with both hands makes it possible to manipulate the machine optimally in various work positions.

The measures enumerated in the subordinate Claims make possible advantageous further developments and improvements of the handle disclosed in the main Claim. it is particularly advantageous that the grip piece of the handle is connected by at least one bar to the machine housing at such a point that one of the holding hands can grasp the grip piece approximately in the prolongation of the axis of the toolholder. In this manner an extremely favourable distribution of the forces of the operator's holding hands with aviewto optimum manipulation of the machine is obtained.For whereas one of the holding hands grasps the grip piece approximately in the prolongation of the axis of the tool holder and therefore occupies the ideal position for causing the feed movement for the drill, the second hand is located a sufficient distance from the axis ofthetoolholderto control the effect of torquves which influence the machine, reliably by means of the long lever arm resulting from the grip.

Further advantages are obtained by the fact that the grip piece of the handle is connected to the machine housing via at least one further bar, namely so that a reach-through aperture is created for at least one of the holding hands, and is surrounded in frame shape by the two bars, by at least one part of the grip piece and by the rear wall of the machine housing. The reliability of grip is improved in this manner, because the machine cannot slip out of the operator's hand. Astable construction of the handle is also obtained if at least two intermediate bars are provided. It is therefore also possible to dimension the intermediate bars relatively narrowly with economy of space, without thereby having to sacrifice the strength of the handle, which strength is absolutely necessary.

Drawing An exemplary embodiment is illustrated in the drawing and explained more fully in the following description. The drawing shows, in a simplified illustration, a hammer drill in side elevation with a handle constructed according to the invention.

Description of the exemplary embodiment A hammer drill, known per se and therefore not described in detail, is designated 1. A handle 4 is arranged at the end of its housing 2 remote from the toolholder 3. The shank, shown fragmented, of a drill inserted into the toolholder 3 is designated 5. 6 is the axis of the tool holder 3, which is identical with the axis ofthe drill shank 5 and with that of the piston of an air cushion percussion unit, not shown. The handle 4 is formed by a grip piece 7, which is connected to the housing 2 via bars 8, 9, 10 at such an interval that the fingers of the hands grasping the grip piece 7 have sufficient room between grip piece 7 and housing 2.The grip piece 7 is at least as long as two hand widths, so that in the exemplary embodiment illustrated, two reach-through apertures 11, 12 are created, through which the user can reach with four fingers of each of the hands grasping the grip piece 7. It is obviously also immediately possible to connect the grip piece 7 to the housing 2 via the bars 8 and 9 alone, or else via the bar 8 alone.

However, in the case of such an embodiment, principally in the case of that mentioned last, it would be necessary to sacrifice the advantage of increased security of grip by reach-through apertures bounded in frame shape.

The arrangement of the bars 8 and 9 on the housing 2 is made so that the holding hand, the gripping position of which is determined by the position of the reach-through aperture 11, is located approximately in the prolongation of the axis 6. The grip piece 7 is of hollow construction and has a removable grip shell 13. The latter is provided with a vibration-damping covering, of textu red foam for example. An electrical switch 14forthe drive motor of the hammer drill 1, and optionallyfurtherelectric- al components, such as a suppressor element 15, for example, are accommodated in the interior of the grip piece 7.Electrical wires 16 are passed through the bar 9 andlorthe bars 8,.10 and connect the switch 14 to the drive motor present in the housing 2, and the other electrical components accommodated in the grip piece 7 to the components in the housing 2 required to be connected electrically to them. A control trigger 17 for the switch 14 is mounted pivotably in the grip piece 7 and projects into the reach-through aperture 11,so that when the grip piece 7 is firmly enclosed by the fingers of the holding hand engaging through the aperture 11,the control trigger 17 is brought into a position in which the switch 14 is closed. When the grip of the holding hand is loosened, the spring-loaded control trigger 17 pivots back automatically into the position in which the switch 14 is open. The electrical connecting cable, which leads through a cable bushing 19 into the handle 4, is designated 18.

Claims

1. Handle for electric motor-driven drilling machines and/or hammer drills, characterised in that a grip piece (7) oriented at an angle to the axis (6) of the toolholder (3) is constructed so that it is at least as long as two hand widths and can be grasped with both hands by the user of the machine (1).

2. Handle according to Claim 1, characterised in that the grip piece (7) is connected to the machine housing (2) via a bar (8) at such a point that one of the holding hands can grasp the grip piece (7) approximately in the prolongation of the axis (6) of the toolholder (3).

3. Handle according to Claim 2, characterised in that a second bar (9 and 10) is arranged between the machine housing (2) and the grip piece (7) at such a point that a reach-through aperture (11, or 11 and 12), which is surrounded in frame shape by the two bars (8 and 9 or 8 and 10), by at least a part of the grip piece (7) and by the rear wali of the housing (2), is created for at least one of the holding hands.

4. Handle according to Claim 2, characterised in that three bars (8, 9, 10) are arranged between the machine housing (2) and the grip piece (7) in such distribution over the tool length of the grip piece (7) that a reach-through aperture (11,12)which is surrounded in frame shaped by two bars (8, 9; 9, 10), by a part of the grip piece (7) and by the rear wall of the housing (2) is created for each of the holding hands.

5. Handle according to any of Claims 1 to 4, characterised in that at the grip piece (7) a control trigger (17), which cooperates with an electrical switch (14), arranged in this region of the grip piece (7) constructed hollowly, for the drive motor, is arranged in the gripping region of that hand which grasps the grip piece (7) approximately in the prolongation of the axis (6) of the toolholder (3).

6. Handle according to Claim 5, characterised in that additional electrical components, such as a suppressor element (15) known per se, for example, are accommodated, in addition to the switch (14), in the interior of the grip piece (7) constructed hollowly.

7. Handle according to either Claim 5 or 6, characterised in that electrical leads (16), which are passed through at least one of the bars (8, 9, 10), connect the electrical components (e.g. 14, 15) accommodated in the grip piece (7) to the drive motor, and optionally further electrical components, present in the housing (2).

8. Handle according to any of Claims 1 to 7, characterised in that the grip piece (7) has a removable grip shell (13) remote from the housing (2), which carries a vibration-damping covering, such as textured foam for example.

9. A handle substantially as herein described with reference to the accompanying drawing.