GB2262159A

GB2262159A - Thrust-applying drill hood

Info

Publication number: GB2262159A
Application number: GB9125952A
Authority: GB
Inventors: Ath Roger Michael De
Original assignee: Kontor Moulding Systems Ltd
Current assignee: Kontor Moulding Systems Ltd
Priority date: 1991-12-06
Filing date: 1991-12-06
Publication date: 1993-06-09
Also published as: GB9125952D0

Abstract

An accessory for an electric hand drill 4 comprises a vacuum chamber 12 for attaching at one end to a surface or object to be drilled and sealed at the other end to the drill. Suction applied to the chamber by a vacuum pump allows atmospheric pressure to provide a drilling force and removes debris through tube 8. The attachment means may be a second vacuum chamber 3 for sealing to a surface to be drilled and nozzle 11 may be turned through 180 DEG to alternatively direct suction into chamber 3 alone or into both chambers 3 and 12. <IMAGE>

Description

ACCESSORY FOR AN ELECTRIC DRILL The invention relates to an accessory for an electric drill. The use of a hand-held electric drill usually requires the application of a significant thrust to the drill. The sustained manual effort required is tiring, particularly if the drilling stance is awkward, as when drilling overhead, for example. The present invention seeks to provide a solution.

According to the invention there is provided an accessory for an electric drill, the accessory comprising a vacuum chamber with two opposite ends; a sealing arrangement at one of said ends adapted to seal about the forward end of an electric drill; attachment means at the other said end of the vacuum chamber for attaching the chamber to a surface or object to be drilled; and a vacuum port for coupling the chamber to a vacuum pump, the arrangement being such that when air pressure within the chamber is reduced by the vacuum pump atmospheric pressure is allowed to draw the said two ends of the chamber together and thereby provide drilling thrust. In this way all or part of the drilling thrust may be provided by the vacuum chamber arrangement and there is the additional advantage that drilling debris may be removed by the vacuum pump.

Various configurations of the vacuum chamber are envisaged and there may be different means for sealing the drill and for attaching the vacuum chamber. For example, a preferred method of attachment is to provide a seal at the said other end of the chamber so that the chamber is forced against a surface to be drilled by atmospheric pressure. However, an alternative arrangement is to provide that the said other end of the chamber should be closed except for a passage for the drill bit and that the attachment means be in the form of a clamp or strap for fixing to an object to be drilled. This is useful for drilling small objects which would not be suitable for forming a seal with the vacuum chamber.

A preferred form of sealing arrangement for the forward end of the electric drill is fitted with a cylindrical bung which is fixed by a strap to the nose of the drill and which constitutes a piston when placed in the vacuum chamber, which in this case is cylindrical. In this context "cylindrical" does not necessarily mean circular cylindrical and the shape of the chamber may be such as to resist turning of the bung in the cylinder, thereby resisting the reactive torque of the drilling operation. For example, the cylinder could be square or triangular.

In another form of vacuum chamber and sealing arrangement, the chamber is a collapsible bellows arrangement and the seal around the forward end of the drill is constituted by a plate which may be attached to the bellows permanently or which may be drawn against an otherwise open bellows end by the suction in the chamber. In this arrangement a mechanical guide would be required to maintain the drill in the required attitude.

In the arrangement where the attachment means is by virtue of a seal against a surface to be drilled, it is possible that the seal may be around the end of a substantially uniform vacuum chamber. However, a preferred embodiment of the invention provides a secondary clamping chamber around the vacuum chamber, the clamping chamber being also provided with a vacuum for clamping to a surface to be drilled and being of greater area than the vacuum chamber. Conveniently, a valve porting arrangement can be used to ensure that the vacuum provided to the clamping chamber and/or the vacuum chamber may be selectively applied so that the device may firstly be clamped in place and secondly vacuum may be applied to the vacuum chamber in order to exert drilling thrust.

The invention will further be described with reference to the accompanying drawings of which: Figure 1 is a side elevation of a drill accessory embodying the invention; Figure 2 is a cross sectional view of the arrangement of Figure 1 in a condition allowing the drill to be withdrawn Figure 3 is a cross-sectional view of the arrangement of Figures 1 and 2 in use; Figure 4 is a side elevation of a drill accessory embodying the invention for drilling an "I" beam; and Figure 5 is a side elevation of a drill accessory embodying the invention and incorporating a bellows seal.

Referring to Figure 1 the accessory comprises a plastics moulding 1 which has a cylinder 2 and a clamping chamber 3. An electric hand drill 4 is fixed by means of a strap 5 to a plastics bung 6 which fits the cylinder 2. A vacuum port 7 is coupled to a flexible tube 8 which is connected to the vacuum inlet of a vacuum pump. The vacuum pump may typically be a vacuum cleaner, preferably of industrial continuous rating but possibly a domestic vacuum cleaner.

Figure 2 shows the device attached to a wall 9 to be drilled. Within port 7 is an inlet tube 10 for the vacuum pump and this has a slanted nozzle 11.

Rotation of the tube 10 to the position shown allows vacuum to be applied to the clamping chamber 3 while a vacuum chamber 12 within the cylinder 2 is effectively cut off from the vacuum pump. Thus, the drill 4 and bung 6 can be inserted into the cylinder 2 and withdrawn while the unit remains clamped to the wall by virtue of atmospheric pressure. A peripheral seal 14 is provided around the chamber 3.

Figure 3 shows the situation when drilling is in progress. The nozzle 11 has been turned through 1800 so that vacuum is applied to the chamber 12 as well as to the chamber 3. The bung 6 is drawn into the chamber by the effect of atmospheric pressure and drill thrust is thereby applied. Drilling commences and drilling debris is withdrawn through the tube 8.

A drill stop 15 is provided to allow drilling to predetermined depths, the extent of the stop 15 being adjustable by means of a screw thread 16.

When drilling is complete the vacuum may be shut off and the unit repositioned for drilling another hole. It will be appreciated that the device in this form is suitable for drilling walls, ceilings, floors and the like and a preferred feature is that the clamping chamber 3 is asymmetrical so that the drill may be positioned close to corners.

Referring to Figure 4 there is shown an arrangement for drilling an "I" beam 17. Since the beam is too narrow to accept the skirt of chamber 3 there is provided a backing plate 18 to which the chamber 3 is applied and which is clamped to the beam by means of a clamp 19.

Figure 5 shows an arrangement whereby sealing of the bung 6 with the cylinder 2 is enhanced by a flexible bellows 20 of polyurethane.

Claims

An accessory for an electric drill, the accessory comprising a vacuum chamber with two opposite ends; a sealing arrangement at one of said ends adapted to seal about the forward end of an electric drill; attachment means at the other said el of the vacuum chamber for attaching the chamber to a surface or object to be drilled; and a vacuum port for coupling the chamber to a vacuum pump, the arrangemen- being such that when air pressure within the chamber is reduced by the vacuum pump atmospheric pressure is allowed to draw the drill towards said other end of the chamber and thereby provide drilling thrust.
2. An accessory for an electric drill as claimed in Claim 1 wherein the attachment means comprise a sealed area whereby suction within the sealed area ensures that atmospheric pressure forces the accessory against the surface.
3. An accessory for an electric drill as claimed in Claim 2 wherein the sealed area is the area of the said other end of the vacuum chamber, said suction being provided by reduced air pressure in the vacuum chamber.
4. An accessory for an electric drill as claimed in Claim 2 wherein there is provided a secondary clamping chamber around the vacuum chamber, the clamping chamber being of greater area than the vacuum chamber and the sealed area being that of the clamping chamber.
5. An accessory for an electric drill as claimed in Claim 4 wherein there is provided a valve parting arrangement whereby the vacuum provided to the clamping chamber and/or the vacuum chamber may be selectively applied so that the device may firstly be clamped in place and secondly vacuum may be applied to the vacuum chamber in order to exert drilling thrust.
6. An accessory for an electric drill as claimed ill Claim 1 wherein the said other end of the vacuum chamber is closed except for a passage for the drill bit and the attachment means is in the form of a clamp or strap for fixing to an object to be drilled.
An An accessory for an electric drill as claimed i any of the preceding claims comprIsing a cylindrical bung adapted to be fitted to the forward end of the drill and which constitutes a piston within the vacuum chamber.
8. An accessory for an electric drill as claimed in Claim 7 wherein the aum chamber and bung are shaped tc resist turning of the bung in the chamber.
9. An accessory for an electric drill as claimed in any of the claims 1 to 6 wherein the chamber Is a coiiapsible bellows arrangement and a seal around the forward end of the drill is constituted by a plate.

An An accessory for an electric dill as claimed in ClaIm 9 wherein the plate Is drawn against an otherwise open bellow. id by the suction in the chamber.