GB2314287A

GB2314287A - Power tool with a fitment

Info

Publication number: GB2314287A
Application number: GB9612819A
Authority: GB
Inventors: John Terrance Crilly
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-06-19
Filing date: 1996-06-19
Publication date: 1997-12-24
Anticipated expiration: 2016-06-19
Also published as: GB2314287B; GB9612819D0

Abstract

A hand held power tool having a body and an elongate fitment 10, 11, 15, 16 projecting from the body, the tool having means to reciprocate the fitment in the direction of its longitudinal axis and the tool including a hand grip 16 surrounding the fitment to guide the fitment during use of the tool. The invention makes it possible to harness the reciprocatory action of a hammer drill, without the rotary action, to drive other tools such as a chisel 15. The fitment includes a drive member 10, 11 which has a threaded socket 12 for connection to the drive shaft of the tool. The drive member 10, 11 is non-rotatably received inside the bore 17 of the second part 15, 16 of the filament but imparts reciprocatory movements thereto via contacting ball bearings 13 and 19 respectively provided on the drive member 10, 11 and the second part 15, 16 of the fitment.

Description

HAND HELD POWER TOOLS The invention relates to hand held power tools, such as hand held power drills.

Hand held power drills are well known, having a body containing a motor, the motor being operable to rotate a drive shaft, and a typical fitment for the tool would be a drill bit which can be rotated by the drive shaft.

In some models, the rotary action of the drive shaft is partially converted into reciprocatory action, for example so that the tool can be used as a hammer drill.

It is now common practice to provide a variety of additional fitments which can be driven by the rotary drive shaft, including circular cutting discs, sanding attachments and the like.

I have now realised that the reciprocatory action can be put to a novel use.

Accordingly, my invention provides a hand held power tool having a body and an elongate fitment projecting from the body, the tool having means to reciprocate the fitment in the direction of its longitudinal axis and the tool including a hand grip surrounding the fitment to guide the fitment during use of the tool.

There may be a rotatable drive member extending from the body to the fitment, the drive member being free to rotate within the hand grip such that no rotary action is transmitted to the hand grip.

Preferably the fitment includes a working bit which has only a reciprocating action, no rotary action being transmitted to the working bit.

The tool has been found to be particularly effective when used to drive a working bit in the form of a chisel. However many other uses are possible and the tool may be used to drive a pointed scribe member, for marking guide lines or patterns on a workpiece, or to drive a hammer head, for driving in nails. There are many other possible applications.

The working bit may be rigidly connected to the hand grip.

There may be a bearing positioned between the rotatable drive member and the hand grip.

There may be means to transmit reciprocatory motion from the drive member to the working bit, but not rotary motion.

There may be a first arcuate thrust surface on the drive member for engagement with a second arcuate thrust surface on the working bit.

Each arcuate thrust surface may for example be provided by a ball bearing.

The hand grip may be manufactured from heat insulation material to reduce the risk that friction between the drive member and the hand grip will cause discomfort to the user.

The body may comprise a conventional hand held power drill, the rotatable drive member being connectable to the drive shaft of the conventional hand held power drill.

The rotatable drive member may be provided with flats to facilitate its disconnection from the drive shaft of the conventional hand held power drill, after use, by means of a spanner.

My invention includes a fitment for a hand held power drill, the fitment having a drive member for connection to a rotatable and reciprocable drive shaft of the hand held power drill, and the fitment including a non-rotatable hand grip for guiding the fitment during use of the tool.

By way of example, a specific embodiment of the invention will now be described, with reference to the accompanying drawings, in which : Figure 1 is a side view of the drive member of a fitment for use with a hand held power tool according to an embodiment of my invention; Figure 2 is an end view of the drive member shown in Figure 1; and Figure 3 is a side view of the hand grip and working bit of this embodiment of fitment.

The fitment shown in the figures is for use with a conventional hand held power drill (not shown) having a conventional rotatable and reciprocable protruding screw threaded drive shaft.

The drive member shown in Figures 1 and 2 comprises a boss 10 from which projects an elongate shank 11. The boss 10 has an internally screw threaded socket 12 and a steel ball bearing 13 is welded to the end of the shank 11. The drive member can be connected to the drive shaft of the drill by screwing the boss 10 onto the threaded drive shaft of the drill. Spanner flats 14 are provided on the outside of the boss 10 so that the drive member can be removed from the drive shaft of the drill after use.

The second component of the fitment is shown in Figure 3 and comprises a chisel bit 15 rigidly connected to a hand grip 16. The hand grip 16 is made of good heat insulation material and contains a bore 17. The bore 17 is lined with a bronze bearing bush 18 and at the inner end of the bore there is embedded a second steel ball bearing 19.

In use the component shown in Figure 3 is slid onto the shank 11 until the ball bearings 13 and 19 come into contact.

The fitment is for use with a drill having a reciprocatory action as well as a rotary action, commonly known as a hammer drill.

Because of the bronze bearing bush 18, the shank 11, driven by the drive shaft of the drill, is free to rotate within the hand grip 16 and so the component shown in Figure 3 can be held and guided in the manner of a conventional chisel. However the inter-engagement of the two ball bearings means that the reciprocatory action of the drive shaft is transmitted to the chisel bit 15 and this greatly facilitates the chiselling action.

The chisel bit 15 shown in Figure 3 is only one of a number of working bits that could be used with the invention. The essential novel principle of the embodiment of fitment shown in the figures is that it enables the reciprocatory action of a hand held power drill to be harnessed to a variety of uses, without the rotary action, which is undesirable for many purposes such as chiselling.

Although the drawings show a fitment for attachment to a conventional drill, it is of course possible to create a purpose built hand tool for use with a range of fitments according to the invention.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A hand held power tool having a body and an elongate fitment projecting from the body, the tool having means to reciprocate the fitment in the direction of its longitudinal axis and the tool including a hand grip surrounding the fitment to guide the fitment during use of the tool.

2. A hand held power tool as claimed in Claim 1, in which there is a rotatable drive member extending from the body to the fitment, the drive member being free to rotate within the hand grip such that no rotary action is transmitted to the hand grip.

3. A hand held power tool as claimed in Claim 2, in which the fitment includes a working bit which has only a reciprocating action, no rotary action being transmitted to the working bit.

4. A hand held power tool as claimed in Claim 3, in which the working bit is rigidly connected to the hand grip.

5. A hand held power tool as claimed in any one of Claims 2 to 4, in which there is a bearing positioned between the rotatable drive member and the hand grip.

6. A hand held power tool as claimed in Claim 5, when dependent on Claim 3 or Claim 4, in which there is means to transmit reciprocatory motion from the drive member to the working bit, but not rotary motion.

7. A hand held power tool as claimed in Claim 6, in which there is a first arcuate thrust surface on the drive member which engages with a second arcuate thrust surface on the working bit.

8. A hand held power tool as claimed in Claim 7, in which each arcuate thrust surface is provided by a ball bearing.

9. A hand held power tool as claimed in any one of the preceding Claims, in which the hand grip is made from heat insulation material.

10. A hand held power tool as claimed in any one of Claims 2 to 9, in which the body comprises a conventional hand held power drill, the rotatable drive member being connectable to the drive shaft of the conventional hand held power drill.

11. A hand held power tool as claimed in Claim 10, in which the rotatable drive member is provided with spanner flats.

12. A hand held power tool as claimed in any one of the preceding Claims, having a working bit in the form of a chisel.

13. A hand held power tool as claimed in any one of the preceding Claims, having a working bit in the form of a pointed scribe member.

14. A hand held power tool as claimed in any one of the preceding Claims, having a working bit in the form of a hammer head.

15. A hand held power tool, constructed and arranged substantially as herein described, with reference to the accompanying drawings.

16. A fitment for a hand held power drill, the fitment having a drive member for connection to a rotatable and reciprocable drive shaft of the hand held power drill, and the fitment including a non rotatable hand grip for guiding the fitment during use of the tool.

17. A fitment for a hand held power drill, constructed and arranged substantially as herein described, with reference to the accompanying drawings.