GB2118462A

GB2118462A - Power tool screwdriving attachment

Info

Publication number: GB2118462A
Application number: GB08200492A
Authority: GB
Inventors: Charles Glen Dunn
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-01-08
Filing date: 1982-01-08
Publication date: 1983-11-02
Also published as: AU1009783A; AU563590B2; NZ202940A; ZA829436B; EP0083860A2; DE3277297D1; ATE29687T1; CA1220058A; EP0083860A3; EP0083860B1; GB2118462B

Abstract

The attachment comprises a tubular portion 1 adapted to fit over a drill bit in a tool chuck and having at one end drive means providing direct driving engagement with the jaws or head of the chuck. The drive means comprises three longitudinally extending projections 2 adapted to engage in the spaces between the chuck jaws. A male or female portion 3 of polygonal or other non-circular configuration fits into or over a correspondingly shaped portion 3a of a nut-runner 5 or accepts a screwdriver bit. The attachment may be retained by grub screws 4. Alternatively the projections are movable radially to engage the chuck key holes 13. The projections are grub screws or are moved by wedge action by rotation of a ring 14. Alternatively, the attachment has a friction sleeve gripping the chuck by wedge action from a rotating ring. <IMAGE>

Description

1

SPECIFICATION

A drive attachment for a power drill or like tool This invention relates to an attachment which can be used to provide a drive connection between a tool such as a screwdriver or a nut-runner or other tool requiring a rotary drive and the chuck of a power drill or like tool utilising a chuck. The invention is primarily concerned with screwdriving but can clearly be applied to other operations for which a power tool can be used e.g. drilling, grinding, engraving, reaming, cutting or countersinking, and could also be used to drive a tap or die holder.

It is well known to use a power drill to bore a hole in wood or masonry, and then to use the same drill to drive a screw into the hole. This normally involves first removing the drill bit from the chuck of the power drill and then inserting the screwdriver bit and re-tightening the chuck. This is time consuming. Another drawback is that the drill bit is often very hot and this makes removal somewhat difficult and maybe dangerous.

It has been proposed to use a screwdriver in the form of a sleeve or tube which fits over the drill bit and can therefore be operated without removing the bit. This results in a considerable saving in time where a large number of holes have to be bored and screws individually inserted.

One of the objects of the present invention is to simplify the drive connection between the screwdriver or similar tool and the power tool.

According to the present invention we provide a drive attachment for a powertool utilising a chuck, the attachment comprising a tubular portion adapted to fit over a drill bit mounted in the chuck and having at one end drive means adapted to provide a direct driving engagement with the chuck jaws or the chuck head of the power tool.

The drive means may comprise one or more lugs or projections and these lugs or projections may extend longitudinally or radially with respect to the tubular portion. If the lugs extend longitudinally they are preferably three or four in number and dimensioned so as to engage in the spaces between the three or four jaws of the chuck.

If the lugs or projections extend radialiy they may be movable radially into driving engagement with the three chuck key-holes in the chuck head.

The attachment according to the invention may be 115 made of metal or of a suitable plastics material, or of a combination of metal and plastics.

The attachment may be made to suit any size of drill bit, or supplied blank i.e. without the centre hole so as to be drilled by the bit over which it will be used giving very accurate location for precision work. For masonry work it will be found that probably only one size of centre hole i.e. 6 mm. clearance will suit 80% to 90% of applications.

The end of the tubular portion remote from the drive means may have an internal or external polygonal or other non-circular configuration adapted to mate with a portion of complementary shape of a tool to be driven by the power tool.

Alternatively this end of the tubular portion may GB 2 118 462 A 1 comprise an integral tool piece such as a screwdriver.

Instead of using lugs or projections the drive means may comprise a friction grip acting on the cylindrical surface of the chuck head. Thus it may comprise a rubber or plastics sleeve or ring provided with means for forcing it tightly against the said cylindrical surface. The parts of the sleeve adjacent the chuck key holes may be forced partly into these holes thereby improving the friction drive.

The invention will now be described with reference to the accompanying drawings which show, by way of example only, several embodiments of the invention and in which:

Figure 1 is a side view of one form of the drive attachment according to the invention, Figure 2 shows the attachment of Figure 1 fitting into a nut runner shown in cross section, Figure 3 is a side view, partly in section, showing a screwdriver in accordance with the invention, Figure 4 is a cross-section, to a larger scale, on the line A-A of Figure 3, Figure 5 is an isometric view of one end of an attachment according to the invention, Figure 6 is a diagrammatic side view of one of the lugs of the embodiments shown in Figures 1 to 5, Figures 7 and 8 are similar views of alternative forms of lugs, Figure 9 is a cross-sectional diagrammatic view of a further embodiment according to the invention, and Figure 10 is a similar view of a still further embodiment, Figure 11 is a diagrammatic view of part of Figure 10.

The attachment shown in Figure 1 comprises a tubular portion 1 having at one end one or more lugs or projections 2 dimensioned so as to fit snugly into the spaces between the jaws of the chuck of a power drill when the jaws are in tight engagement with a drill bit of a size suitable for making a hole to receive a threaded member of the kind to be used. The other end of the tubular portion 1 comprises a portion 3 of polygonal or other non-circular section. Over this portion 3 can be fitted a complementaffly shaped part 3a of e.g. a nut runner 5 shown in Figure 2. One or more grub screws 4 may be used for. holding the attachment in place, the screw or screws 4 may be used for holding the attachment in place, the screw or screws bearing against the side portions of the drill bit. When a hole has been drilled using the drill bit, the nut runner 5 is simply slipped overthe drill bit so that the parts 3 and 3a are in engagement.

Preferably the ends of the lugs are bevelled or rounded or otherwise shaped to facilitate ready insertion into the chuck. The length of the lugs should be such that the end faces 6 between the lugs come into contact with the end portions of the chuck jaws. It has been found that if the lugs are long they tend to get bent in use. Hence it is advisable to make them just long enough to give a good driving engagement with the chuck jaws.

The opposite side faces 7 (Figures 4 and 6) of the lugs 2 are preferably parallel so as to cooperate with the opposed parallel faces of adjacent chuck jaws.

2 GB 2 118 462 A 2 Alternatively the non-driven faces 8 of the lugs may be sloping as indicated in Figures 7, 8 i.e. the lugs are each in the form of a right-angled triangle the hypotenuse of which is formed by a non-driven face of a lug. It is believed that this shape increases the strength of the lug, though it has the disadvantage that the drill cannot be used in reverse to withdraw the screw. The embodiment shown in Figure 3 is similar to that in Figure 1 but is long enough to shroud the drill bit completely. At the end opposite to the lugs 2 the attachment has a recess 8 e.g. of hexagonal section to receive e.g. a screwdriver bit 9.

Clearly, instead of providing a separate bit 9, the end of the portion 1 could be simply shaped as a screwdriver or other tool.

The attachment according to the invention may be made by drilling a bore in a solid metal rod and then forming the lugs by a grinding operation. Alterna tively the lugs may be first formed by a forging operation, followed by a drilling operation to pro duce the bore of the tubular portion.

It will be clearthat the dimensions of the attach ment e.g. the diameter of the bore of the hollow sleeve will vary with the size of the drill bit being used. Similarly the cross-sectional dimensions of the lugs will vary with the size of the drill bit. By way of example it was found that a 5.5 mm. drill bit required an attachment having lugs that were approximately 3 mm. x 4 mm. and equally spaced apart. The internal diameter of the tubular portion was 5.7 mm.

and the external diameter 10.2 mm.

In the example shown in Figure 9 the attachement comprises a tubular portion 11 which fits over a drill bit D and is rigidly connected to a tubular housing or sleeve 12 which fits over the head H of the chuck. 100 This housing 12 is provided with three projections (not shown) which can readily be moved into driving engagement with the chuck key holes 13 of the drill chuck. The projections may be in the form of pins, rods or balls and known mechanism such as a locking ring 14 is provided for advancing the projec tions into driving engagement with the holes 13 and releasably holding them there during use of the screwdriver. Once again it is not necessary to remove the drill bit and a considerable saving in time 110 is effected.

The locking ring 14 may comprise a ring with three tapered sections each of which forces one of the lugs or projections into one of the holes 13 when the ring is rotated.

In an alternative arrangement the locking ring may comprise several tapered sections adapted to clamp a ring of rubber or plastics material against the cylindrical outer surface of the chuck head. It will be found that the friction between the chuck head and the rubber or plastics ring provides sufficient grip to transmit drive to e.g. a screwdriver or like tool.

In a modification of the example shown in Figure 9, instead of making the parts 11, 12 integral with each other, the tubular portion 11 may have an end section or a recess of polygonal or other non-circular configuration adapted to fit snugly into or over a complementarily shaped recess or section at one end of the sleeve 12. Instead of having a locking ring 14 the sleeve 12 may have three projections located so that they can be advanced into the three chuck key holes 13. Each projection may comprise a grub screw having an unthreaded hole-engaging portion at its inner end.

In the example shown in Figure 10 the projections or lugs 2 are partly embedded in an outer member 18 which may be shaped somewhat in the form of a hollow screwdriber handle. It may be made of an injection moulded plastics material with the lugs or projections projecting internally thereof. The attachment may be secured in place by means of one or more grub screws 15 engaging the chuck head or 16 engaging the drill bit. The other end 17 may be shaped (e.g. hexagonal) to receive a complementarily shaped socket in a tool to be driven. The whole unit could be diecast Mazack and therefore inexpensive.

Figure 11 shows a part of the embodiment of Figure 10 with certain parts omitted forthe sake of clarity e.g. only one of the lugs 2 is shown. The drill bit D is shown held by means of chuck jaws.J.

In a modification of the embodiment of Figures 10, 11, instead of having three separate metal lugs 2 embedded in the plastics member 18, the three lugs may project from a single cylindrical metal member which is itself embedded in the plastics material.

It will be clear that the drive attachment according to the invention can be used to drive any known type of screwdriver bit, e.g. slotted, Phillips, Pozidriv, Supadriv or Robinson or a nut runner or Alien Key driver etc., or a tap holder, die holder, chuck or collet, flexible drive countersink bit or other rotary drive.

Claims

1. A drive attachment fora power tool utilising a chuck, comprising a tubular portion adapted to fit over a drill bit mounted in the chuck of the power tool, and having at one end drive means adapted to provide a direct driving engagement with the chuck jaws or the chuck head of the power tool.

2. An attachment as claimed in claim 1 wherein the drive means comprises one or more lugs or projections.

3. An attachment as claimed in claim 2 wherein the lugs or projections extend longitudinally with respect to the tubular portion.

4. An attachment as claimed in claim 2 wherein the lugs or projections extend radial ly with respect to the tubular portion.

5. An attachment as claimed in claim 4 wherein the lugs or projections are movable radially into engagement with the chuck key holes in the chuck head.

6. An attachment as claimed in claim 2 wherein the lugs or projections are dimensioned to fit snugly between the jaws of the chuck of the power tool.

7. An attachment as claimed in any of claims 2 to 6 wherein the ends of the lugs or projections are rounded or bevelled to facilitate engagement thereof between the chuck jaws or in the chuck key holes.

8. An attachment as claimed in claim 1 wherein the drive means comprises a flexible sleeve or ring provided with means for tightening it into frictional engagement with the cylindrical surface of the chuck ok 3 GB 2 118 462 A 3 head.

9. An attachementas claimed in any preceding claim wherein the end of the tubular portion remote from the drive means has a portion of polygonal or other non-circular configuration adapted to mate with a porton of a complementary shape of a tool to be driven by the power tool.

10. An attachment as claimed in claim 9 wherein the polygonal or other non-circular portion compris10 es a female portion.

11. An attachment as claimed in claim 9 wherein the polygonal or other non-circular portion comprises a male portion.

12. A power driven screwdriver comprising an 15 attachment as claimed in any of claims 1 to 11.

13. An attachment as claimed in claim 1 substantially as hereinbefore described with reference to any of the accompanying drawings.

Printed for Her Majesty's Stationery Office, by Croydon Printing Company Limited, Croydon, Surrey, 1983. Published by The Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.