WO2007017681A2

WO2007017681A2 - Power tool accessory

Info

Publication number: WO2007017681A2
Application number: PCT/GB2006/002971
Authority: WO
Inventors: Ross J. Bryan
Original assignee: Bryan Ross J
Priority date: 2005-08-09
Filing date: 2006-08-08
Publication date: 2007-02-15
Also published as: GB2442678B; GB2442678A; GB0802287D0; WO2007017681A3; GB0516344D0

Abstract

A power drill accessory for use with a power drill for guiding a drill bit, comprises a body including a rack (2) which releasably holds drill bit guide members (5) in separate compartments, each guide member including an bore dimensioned to receive a drill bit of an appropriate diameter, the body having a head region (1 , 4) which releasably holds a selected guide member in a position for guiding a drill bit held in a power drill, and a handle member (3) for gripping in one hand, which extends over the rack and which is joined at one end, at the head region, to the rack. The lower surface of the head region, partly defined by the lower surface of the selected guide member, provides an extended grip surface area for gripping against a work surface. The lower surface of the guide member has channels for exhausting drill waste material.

Description

POWER TOOL ACCESSORY

The present invention relates to a power tool accessory, providing a guide for a drill bit. Background Art

A drill guidance device is shown in EP-A-0894560 comprising a single tube attached at one end to a semicircular plate. The underside of this plate has some form of adhesive surface. There are a number of inherent problems: the fact that the design consists of a single tube means that the device is only capable of working with a single drillbit size and is therefore very inflexible to the user. The adhesive surface provides initial grip, until contamination by other substances or sufficiently high number of uses that its adhesive qualities are severely reduced and its ability to maintain a stable position and therefore guide drilling are hampered. The flush nature of both the semicircular plate and the single tube to the surface being drilled into implies that there is no escape path for drilling waste. Such waste would therefore compact in the hole being produced. Furthermore, the design is such that the user's fingers are necessarily in close proximity to the rotating. drill bit, raising questions about safe usage of the device. A second design in the marketplace, see www.screwfix.com - Portable

Drill Stand, and a similar construction shown in US Patent No. 3,874,810, comprises a metal jig into which the user clamps their drill. One then holds onto the metal jig and presses the drill down guided by two sprung loaded metal struts that connect a circular plate on the drilling surface and the clamp into which the drill is placed. The nature of the clamp is such that only drills of a single collar size can be attached; the clamp and base plate design prevents the user making use of any integral depth measures which are a common feature of modern power drills; the drillbit itself is not supported at the point of contact and can therefore still be susceptible to a small degree of movement and offers no reduction in the amount of surface deterioration that can aiso be a drilling problem. US Patent Nos. 3,775,020 and 3,804,546 disclose drill bit guides comprising a handle and a guide member comprising a rotatable template having various sized apertures for respective drill bit sizes.

US Patent No. 5,743,916 discloses a drill guide for a surgical drill for performing very delicate drilling operations. It comprises a telescopic tubular guide into which a drill bit is inserted. A tubular ferrule is fitted into the top of the tubular guide, having an internal diameter matching that of the drill bit. A handle is attached to the tubular guide, and has a row of cylindrical bores that receive tubular ferrules of different internal diameters, in a snap fit manner. A ferrule may thus be chosen to match the size of the drill bit being used in a drilling operation.

Such an arrangement would not be suitable for a power drill, where ruggedness to cope with rough usage, and the ability to cope with a large quantity of drilling, is required. The depth occupied by the guide is prohibitive in its ability to drill holes of any useful depth. The guide offers no waste escape and has no surface stability characteristics i.e. the area of contact with the drilling surface and its height above the surface make this guide as unstable to use as no guide at all.

Summary of the Invention

The concept of the present invention is to provide an accessory for a power drill for DIY use, which enables the drill bit to be guided to make an accurate drill hole, in a variety of surfaces, and where the drill may be subject to rough usage.

In general terms, the invention provides a power drill accessory, comprising a body member including storage means for releasably holding a plurality of drill bit guide members, each guide member including an aperture dimensioned to receive a drill bit of an appropriate diameter, the body member having a head region including holding means for releasably holding a selected said guide member in a position for guiding a drill bit held in a power drill, and the body member including a handle member for holding and positioning the accessory.

The lower surface of the head region provides an extended surface area around the drill bit aperture when drilling takes place for gripping the accessory in its defined position against the work surface. Further this extended surface area may be recessed or apertured in an appropriate manner to permit escape of waste material from the drilling operation region and to maintain proper contact of the surface with the work surface. In many drilling operations for DIY, a large quantity of waste material may be generated. A guide member is insertable into the holding means from beneath, and the lower surface of the guide member defines the lower surface of the guiding region. The upper surface of the guide member may engage against the holding means for retention. Should a power drill be moved into contact with the accessory, it may contact the guide member rather than the holding means. Thus reaction forces and other forces that arise in drilling will be taken up principally by the guide member, and the guide member has a strong and sturdy construction to absorb these forces.

The guide member has a body including a frame that may be rectangular or square. Other body shapes are possible, for example circular or star-shaped. Equivalently, the body may be regarded as of a hollowed construction. The body may be formed of side faces, with strengthened corner regions having diagonal ribs that lead to a central tube that contains a bore for receiving and guiding a drill bit. The diagonal ribs may contain channels that lead from the central bore to the exterior of the guide member and which serve as conduits for waste material from the drilling operation. The upper surface of the guide member may comprise a circular disk having a central aperture that defines the opening of the bore and which provides a reaction surface should the power drill come into contact.

Side faces of the body may be flexible and may have engagement ribs along their lower perimeter. These may engage corresponding channels in the holding means to enable a snap fit or snap fit of the guide member in the holding means, so that there is no risk of the guide member falling out of the holding means during use.

In a preferred embodiment, the storage means comprises a rack or tray like part that has a plurality of compartments for receiving respective guide members. The compartments of the storage rack may have channels for receiving said ribs of the guide members for positively retaining the guide members. The underside and/or upper surface of each compartment may have a U shaped - A - cutout for enabling access by a finger to remove a guide member in a single sliding operation, against the retention force.

Thus in a first aspect, the invention provides a power drill accessory, comprising a body member including storage means which releasably holds a plurality of drill bit guide members, each guide member including a bore dimensioned to receive a drill bit of an appropriate diameter, the body member including a head region that includes holding means for releasably holding a selected said guide member in a position for guiding a drill bit held in a power drill, said storage means comprising a rack extending from said head region and having a plurality of compartments for receiving respective guide members, and the body member including a handle member extending over said rack, and which is joined at one end to said head region, and a lower surface of the head region surrounding said bore being adapted for positioning adjacent the work surface to be drilled to provide an extended grip surface area. In a further aspect, the invention provides a power drill accessory, comprising a body member including storage means for releasably holding a plurality of drill bit guide members, the body member including a head region that includes holding means for releasably holding a selected said guide member in a position for guiding a drill bit held in a power drill, said storage means comprising a rack extending from said head region and having a plurality of compartments for receiving respective guide members, and the body member including a handle member extending over said rack, and which is joined at one end to said head region, and a lower surface of the head region being adapted for positioning adjacent the surface to be drilled. In a further aspect, the invention provides a guide member for a power drill accessory for guiding a drill bit, the guide member having a body including a frame that supports a central portion that contains a bore for receiving and guiding a drill bit, the frame being such as to permit escape of drilling waste material from the bore. In accordance with the invention, the replaceable nature of the guide members ensures that no matter what size drillbit the user wishes to guide, there is a corresponding guide member to fit (within practical constraints). Rather than use a deteriorating adhesive surface to provide grip the invention may, in a preferred embodiment, use rubber or similar inserts, which are placed away from drilling waste and can easily be renewed for continuing service grip. Equally, their relatively low surface area compared to the overall dimensions over which a user will apply force, namely through the handle, means that a higher degree of pressure will be transferred through these rubber grips therefore enhancing their performance. The arrangement of waste channels in the guide members and two corresponding channels in the holding means ensure that waste materials are successfully removed from the drilling point and prevent the build-up of waste.

Whereas prior art designs may seek to clamp onto the power drill itself, the present invention does not, and has no associated limitations of drill size, given that the interface between drill and guide occurs only at the drillbit itself and can be matched precisely by changing the guide members. The guiding region of the invention is deliberately of a low-profile form such that any user may continue to perform a depth measurement function with the extending arm devices commonly found on most power drills; the arm will pass successfully alongside the head and onto the drilling surface. When drilling into surfaces of low integrity a degree of flaking and crumbling can result in hole enlargement, and therefore unsatisfactorily accurate holes (enlarged holes may not fit the desired insert or allow some degree of unwanted movement). This problem is significantly reduced by the invention because the guide position is at the contact point on the drilling surface. The waste channel walls of the guide member and head component may press directly onto the drilling surface and therefore serve to prevent flaking and crumbling by preserving the integrity of the surface itself.

Brief Description of the Drawings

A preferred embodiment of the invention will now be described with reference to the accompanying drawings wherein: - Figure 1 is a perspective view of the power drill tool accessory of the invention, showing guide members in a holding means and in a compartment of a storage rack;

Figures 2 and 3 are perspective views of the accessory of the preferred embodiment, from above and below;

Figures 4 and 5 are detail perspective views of the guiding region of the preferred embodiment, from above and below;

Figures 6 and 7 are detail perspective views of a guide member of the preferred embodiment, from above and below; and Figures 8 to 11 are diagrams showing how the preferred embodiment of the power drill accessory is used.

Description of a Preferred Embodiment

Referring to Figure 1 , the main body of the power drill tool accessory consists of five elements: a head region or holding means (1), a storage block or rack (2), a single pivot handle (3), a joining pyramid (4), and removable guide members (5)

Guide members (Figures 6 and 7):

The guide members (5) are replaceable components which can be inserted into the head (1) of the main tool. Each guide member is of identical dimensions, but the core or bore running through the centre (6) is of varying diameter, to correspond with the varying diameter drill bits that a user may wish to select. The user can interchange any guide member into the head of the tool to satisfy the drilling task requirement.

The upper surface of the guide member is that of an annulus or disc (7), with raised markings. One group of markings indicates the diameter size of the hole (8). The other four markings are positioned at the points of a compass rose North South East and West (9), but are offset 45° therefore pointing at each corner of the guide member. This alignment is such that when a guide member is positioned in the head of the drill accessory, the markings are also then at 45°. When the accessory is picked up and held against a surface in conjunction with a power drill, the ergonomic position to use the accessory is at 45° to that of the power drill. Therefore, the offset of the raised markings will be moved into a vertical and horizontal alignment that will naturally correspond with the typical surface markings to designate a drilling point (Figure 8).

At the centre of the upper surface of the guide member is the central bore (6), that serves to guide the drillbit. The upper aperture to this bore is countersunk to produce a downward sloping surface (10) that narrows to the central hole which is of the correct measured diameter as indicated on the upper surface by the raised markings i.e. the hole on the uppermost surface of the guide member will exceed that shown on the surface markings, e.g. 12 mm at the upper surface, but will reduce to correspond to the marked measurement, e.g. 4 mm.

The outer circle of the upper surface is maintained to a depth of approximately 2 to 3 mm to provide a thin disc (11 ). This disc shape sits upon the predominantly cubic structure (100) that makes up the rest of the guide member, although in practice the circular and cubic elements are moulded as one piece. The cubic structure (100) comprises a frame with side faces (102), strengthened corner regions (104), and diagonal ribs (106) that lead from respective corner regions to a central part (108) that defines the central bore (6).

Observing each of the four sides (102) of the guide member shows that two incisions had been made in a vertical fashion and that these incisions run to the bottom surface of the guide member (12). This effectively creates a natural hinge at the upper edge (13) of the resultant face of plastic (14). Running horizontally along this face approximately 1 to 2 mm from the lower edge is a small rib of plastic (15), which is integral to the holding mechanism both in the head of the tool and in the storage compartments (described later as the snap- fit' mechanism).

Observing the guide member from below, figure 7, one can see a number of complex features. It is also clear that there is a cavity behind each of the plastic faces (16) on all four sides of the cube as described in the previous paragraph; this cavity allows the plastic face and the rib to flex, a requirement for the snap-fit mechanism. The central core hole is apparent at the base of the guide member and will still correspond with the diameter measurement ^• illustrated by the markings on the upper surface. Again, extending at 90° angles from the centre of the guide member are four approximately triangular waste channels which lead from the centre hole to each of the four corners of the guide member (17). These channels serve to act as a conduit for waste material during the process of drilling, being bounded by walls (18). It is important that the orientation and number of these channels is correct such that, regardless of which of four possible positions the guide member is placed into the head of the tool, a waste channel will be correctly aligned and able to remove waste under gravity.

The guide member itself has certain characteristics to maximise its usability. It is transparent so that light can penetrate through the object and onto the surface where the drill marking may be, although this is not essential to using the guide in the drilling process it is a design feature believed to make operating considerably easier. The guide member is manufactured from a plastic with properties similar to that of nylon, which, has sufficient wear characteristics: the plastic used must be self lubricating so as to reduce friction and therefore heat during the high rpm drilling action, and have sufficient structural integrity to prevent rapid deterioration if drilling is affected outside of true alignment with the core hole. It is also design feature that the guide member can be rotated into four different orientations and used effectively; this allows the user to alter the orientation if wear at any particular point becomes too severe. Simultaneously, the square shape of the guide members prevents them from rotating in the head as torque is applied by the drillbit. In a modification, the ability to drill at an angle is provided by guide members with an appropriately angled core holes e.g. at 15° or 30° to the axis of the guide member.

Main Body (Figures 1 to 5):

The main body of the tool consists of four elements: the head (1), having a holding means into which guide members are inserted; a storage rack (2)having a series of cavities where spare guide members can be stored; a single pivot handle (3), and ergonomic handle attached at the head end of the tool only; and a joining pyramid (4), the centre block with a shape approximating to a pyramid to which the handle storage block and head are all integrally moulded. Referring to Figures 4 and 5, the upper surface of the holding means (1) is annular (19), consisting of a complete inner circle (20) and a larger outer circle which is partially interrupted in the moulding that joins it to a pyramid section (21 ). On the upper surface there are raised markings similar to those found on the guide members and again at 45° angles to the compass rose (22).

Regardless of which orientation the guide member is inserted these surface markings will match those on the guide member and reinforce the facilitation of alignment provided by the guiding tool, as illustrated in Figure 8. The height of the holding means is essentially the same as the height of the guide members such that the lower surfaces are flush with each other, and the disc 7 of a guide member projects somewhat from circle 20.

Referring to Figure 5, towards the lower surface on both the side of the head nearest the main body and that surface directly opposite, there is a small channel running horizontally and therefore parallel to the lower surface (23a). This channel is complementary to the rib feature (15) present on all four sides of the guide member, and it is into this channel that the guide member will fasten under the snap-fit mechanism described hereafter. The snap-fit mechanism is a method of fastening the guide members into the head element by pressing the cube upwards from the lower surface into the head element the circular upper surface of the guide member will naturally locate into the circular hole of the head. The square nature of the cube itself will force the guide member to locate in one of the four orientations and as the guide member is snapped entirely into the head, the ribs on the flexible plastic faces 14 will bend inwards until the rib is positioned level with the channel where it will pop into place, thus fastening it in the head. The mismatch of shapes i.e. the disc (11 ) in the upper surface of the guide member and its square body creates an overhang (24 - figure 6), meaning that a single cube [guide member] cannot be snapped right through the head. The rib and channel mechanism is therefore designed to prevent guide members dropping out of the bottom surface where the matching shapes would allow this to happen otherwise. This is particularly pertinent for the user when they have located a guide member in the tool and are then transporting the tool or depositing it somewhere whilst attending to the other drilling matters such as changing the drillbit size. To release the guide member from the head the user simply has to press down on the upper surface of the guide member (7) and the flexible plastic faces (14) will enable the ribs (15) to disengage from the head channels (23) as described. Similarly, there are notches in the mould ribs of the head which also act to catch the guide member ribs (23b) and assist in the snap-fit mechanism. The waste removal channels 17 in the guide members are associated with two registering channels in the lower surface of the tool head (25). These are located 90° apart from the head centre point, being 45° either side of the centre line (26) joining the head element to the main body of the tool. Again, this 45° offset on either side ensures that whichever orientation the guide member is placed into the head, a waste removal channel from both the guide member and the head will line up exactly. The combined channel of the guide member and head will create a continuous vertical outlet, such that drilling waste will fall away from the point of contact between the drill and the surface under gravity. The guide member storage rack (2, Figures 2,3) consists of a large rectangular body, which is a hollow in form but subdivided into separate compartments (27, a-d), the purpose of which is to store unused guide members. The lower surface of the storage compartment consists of a flat plane interrupted by a sequence of horseshoe shaped cutouts. In a modification, not shown, both the upper and lower surfaces of the storage compartment consist of flat planes interrupted by a sequence of horseshoe shaped cutouts. The vertical dividing faces (30) of the storage compartment extend from the upper surface down to the lower surface, contacting the lower surface in between each of the cut-out shapes. Thus, when this arrangement is repeated along the length of the storage compartment a series of rails (31) is created upon which the guide members can rest. This combination of rails and horseshoe shaped cavities allows the guide members to be safely stored, but for the user to insert either a finger or appropriate device into the cut-outs to retrieve the desired guide member size (Figure 9). In each storage compartment 27 a similar arrangement of channels to that in the head is present in the dividing walls (32). The channels are present on the three compartment walls, at an equal height from the storage compartment rails to that of the rib present on the guide member from the guide member's base (31), running parallel to them. These channels are again complementary to the rib (15) and flexing faces (14) of the guide member so that when a guide member is pressed into the storage compartment these two elements intermesh, and the guide member is secured.

On the lower surface furthest from the head, there is a shallow cavity or depression (33), which runs approximately the width of the final supporting rail of the storage compartment. Into this cavity are fastened pieces of rubber (34), or similar material, appropriately formed to provide one part of the non-slip element of the design (the other being on the lower surface of the joining pyramid (4)). The handle (3) is comprised of a hollow structure approximating to a cylinder, but with a degree of curvature throughout its length (35), lending itself better to a natural grip by the human hand. The surface of the handle features a degree of pitting and etching that creates very small scale relief which improves the gripping characteristics of the handle itself (not illustrated). Whilst the end of the handle nearest the head is integrally moulded into the joining pyramid (36), the other end is unrestrained, the rigidity of the plastic providing sufficient support in use. This unrestrained end face is not fashioned to be parallel with the end face of the storage compartment over which it hangs, but is instead deliberately angled to moderate degree (37). This facilitates the ease with which the handle can be hooked into storage locations such as the pocket or belt of the user or any form of tool racking.

The joining pyramid (4) consists of a hollow plastic body of three triangular faces angled up to a point. The larger of the triangular faces (38) connects to the head component at its base (39) and has curved surfaces at its other sides (40) which join the smaller two triangles (41 ). At the apex of the structure is a small half dome configuration (42), which has the same curvature as the handle unit moulded into it. At the base of the joining pyramid is a suitable structure to correspond with and therefore complete the unification of the head and storage component parts (43). The lower surface of the joining pyramid, attending to the head end features a similar shallow depression to that described in the storage compartment and the same rubberised gripping feature (44,45).

Manner of Use (Figures 8 to 11 )

Figure 8 shows the guidance device in position against a drilling surface, the user having the power drill in their right hand. As such the naturally ergonomic position to hold the guide is at 45° in the left hand, whereupon the guide markings on the upper surface of the head and guide member assume a vertical and horizontal cross. This is intended to correspond with the typical location markings on the drilling surface as potentially described by a spirit level or similar tool.

By positioning the guiding element in the head unit (1) as described and having this prominent from the joining pyramid (4), there is a sensible degree of separation of the user's hands from the moving parts of the drill . The predominantly hollow structure and chosen lightweight materials of the new drill guide design ensure that the overall weight of the object adds very little burden to the drilling process and could be handled with ease [and in safety] by all potential operators.

Figure 9 demonstrates the removal of guide members from the storage compartment. From their fully recessed position, locked into the compartment, a user may remove a guide member from its snap-fit location either by pinching said member between digits, fitting into the horseshoe cut-outs; or by inserting a suitable implement into the central bore, and using that implement as a lever. Figure 10 shows the guide device used in conjunction with a power drill that includes an adjustable depth measurement rod. These are common among many power drills and as such, the low profile head design is deliberate in accommodating for the ongoing need to use a depth gauge in conjunction with the guiding facility.

Both the guide members and the head element will be manufactured from a fully or semi transparent material. By doing so, sufficient light will reach a given marked surface and it will therefore be possible to place the drill-guide over the marking and still find it when using drill bits in the majority of cases. However, if the core hole is very small for a corresponding drϋlbit it is conceded that to use the new design drill guide, placement of the head over the top of a marked position may obscure it. In actual fact this issue can be circumnavigated, as shown in Figure 11 by pushing the drill bit through the guide member in position, then placing the drill bit onto the marking on the surface, with the drill in position, load can then be transferred to the guide handle which will lock into position on the drilling surface and thereafter ensure accurate drilling. Modifications

For levelling and detection, either the joining pyramid or the integrated storage compartment may be altered by introducing a series of cut-outs into which 2 spirit levels at 90° to each other could be mounted (46 - Figure 1). The user may then place the lower surface of the drill guide tool either horizontally or vertically on the surface which they wish to drill into and simultaneously check the degree of levelling. Secondly, to avoid drilling into pipe work and/or electrical cabling a number of detection devices exist and are commonplace in the market. It is proposed therefore, that appropriate circuitry for such a device be housed inside the joining pyramid (4). The sensor for which would be placed at the lower surface of the joining pyramid (47) and the on/off, mode, and sensitivity switches would be positioned at the apex of the joining pyramid (48). Relevant cut-outs would be made into the body or handle to house these switches and sufficient ribs built into the joining pyramid internally to secure that circuitry required for this detection function.

Claims

1. A power drill accessory, comprising a body member including storage ' means which releasably holds a plurality of drill bit guide members, each guide member including a bore dimensioned to receive a drill bit of an appropriate 5 diameter, the body member including a head region that includes holding means for releasably holding a selected said guide member in a position for guiding a drill bit held in a power drill, said storage means comprising a rack extending from said head region and having a plurality of compartments for receiving respective guide members, and the body member including a handle 10 member extending over said rack, and which is joined at one end to said head region, and a lower surface of the head region surrounding said bore being adapted for positioning adjacent the work surface to be drilled to provide a grip surface area.

2. An accessory according to claim 1 wherein said lower surface is 15 recessed or apertured to permit escape of drill waste material.

3. An accessory according to claim 1 or 2, wherein the lower surface of the head region has rubberised areas to engage the surface to be drilled and to prevent slippage.

4. An accessory according to claim 3, wherein the lower surface of the head 20 region is coplanar with a lower surface of the rack, and wherein the lower surface of the rack has rubberised areas to engage the surface to be drilled and to prevent slippage

5. An accessory according to any preceding claim, wherein the lower surface of a guide member within said holding means provides at least part of

25 the lower surface of the head region.

6. An accessory according to any preceding claim, wherein said guide member is insertable into the holding means from the direction of said lower surface .

7. An accessory according to claim 6, wherein upper surface regions of the 30 guide member abut said holding means so as to prevent upward movement of the guide member.

8. An accessory according to any preceding clam, wherein the upper surface of the guide member includes a circular disk portion providing an entry to said bore.

9. An accessory according to any preceding claim, wherein the guide member has a body in the form of a frame that supports a central portion containing a bore.

10. An accessory according to claim 9, wherein the frame has ribs that support said central portion.

11. An accessory according to claim 10, wherein the ribs contain channels that lead from the central bore to the exterior of the guide member and which serve as conduits for waste material from the drilling operation.

12. An accessory according to any of claims 1 to 10, wherein the guide member includes channels that lead from a central area to the exterior of the guide member and which serve as conduits for waste material from the drilling operation.

13. An accessory according to claim 11 or 12, wherein said channels communicate with registering waste channels in said holding means.

14. An accessory according to any preceding claim, including first interengaging means for enabling a snap fit of the guide member in the holding means.

15. An accessory according to claim 13, including second interengaging means for enabling a snap fit of the guide member in said compartments of said rack.

16. An accessory according to claim 14 or 15, wherein the guide member has a plurality of side faces, each side face having a guide member interengaging means on its lower edge, and each side face being flexible to permit inward movement of the interengaging means.

17. An accessory according to claim 16, wherein the guide member interengaging means comprises a rib for engaging in a channel in said holding means and/or said compartment.

18. An accessory . according to any preceding claim, wherein a surface of each compartment has a cut-out portion for enabling access by a finger to remove a guide member in a single sliding operation.

19. An accessory according to any preceding claim wherein the guide member is non-circular in shape to prevent rotation under use

20. An accessory according to any preceding claim, wherein the guide member is wholly or partially transparent.

21. An accessory according to any preceding claim, including alignment markings on both the holding means and the guide members, which are positioned to align with each other, and which are positioned at an acute angle relative to said handle member

22. A power drill accessory, comprising a body member including storage means for releasably holding a plurality of drill bit guide members, the body member including a head region that includes holding means for releasably holding a selected said guide member in a position for guiding a drill bit held in a power drill, said storage means comprising a rack extending from said head region and having a plurality of compartments for receiving respective guide members, and the body member including a handle member extending over said rack, and which is joined at one end to said head region, and a lower surface of the head region being adapted for positioning adjacent the surface to be drilled .

23. An accessory according to claim 22 wherein said lower surface has rubberised areas to engage the surface to be drilled and to prevent slippage.

24. An accessory according to claim 22 or 23, wherein the lower surface of the head region is copianar with a lower surface of the rack, and said handle member extends over said rack.

25. An accessory according to claim 24, wherein the lower surface of the rack has rubberised areas to engage the surface to be drilled and to prevent slippage

26. An accessory according to any of claims 22 to 25, wherein said holding means is such that a guide member is insertable into the holding means from the direction of said lower surface.

27. An accessory according to any of claims 22 to 26, including waste channels in said holding means.

28. An accessory according to any of claims 22 to 27, including first interengaging means for enabling a snap fit of the guide member in the holding means.

29. An accessory according to claim 28, including second interengaging means for enabling a snap fit of the guide member in said compartments of said rack.

30. An accessory according to any of claims 22 to 28, wherein a surface of each compartment has a cut-out portion for enabling access by a finger to remove a guide member in a single sliding operation.

31. An accessory according to any of claims 22 to 28, including alignment markings on the holding means and which are positioned at an acute angle relative to said handle member.

32. A guide member for a power drill accessory for guiding a drill bit, the guide member having a body including a frame that supports a central portion that contains a bore for receiving and guiding a drill bit, the frame being such as to permit escape of drilling waste material from the bore.

33. A guide member according to claim 32, wherein the frame has ribs supporting said central portion.

34. A guide member according to claim 32 or 33, wherein the ribs contain channels that lead from the bore to the exterior of the guide member and which serve as conduits for waste material from the drilling operation.

35. An guide member according to any of claims 32 to 34, wherein the guide member includes channels that lead from a central area to the exterior of the guide member and which serve as conduits for waste material from the drilling operation.

36. A guide member according to any of claims 32 to 35 wherein the body is rectangular in shape.

37. A guide member according to any of claims 32 to 36, including interengaging means for enabling a snap fit of the guide member in a holding means.

38. An guide member according to claim 37, wherein the body has a plurality of side faces, each side face having an interengaging means on its lower edge, and each side face being flexible to permit inward movement of the interengaging means.

39. A guide member according to claim 38, wherein the interengaging means comprises a rib for engaging in a channel in a holding means.

40. A guide member according to any of claims 32 to 39, wherein the guide member is non-circular in shape to prevent rotation under use

41. A guide member according to any of claims 32 to 40, wherein the guide member is wholly or partially transparent.

42. A guide member according to any preceding claim, including alignment markings on an upper surface

43. A guide member according to any of claims 32 to 42, wherein the upper surface of the guide member comprises a circular disk portion having a central aperture that defines the opening of the bore and which provides a reaction surface should the power drill come into contact.

44. A power tool accessory substantially as described with reference to the accompanying drawings.

45. A guide member, for use with a power tool accessory, substantially as described with reference to the accompanying drawings