GB2338438A

GB2338438A - A rotary tool

Info

Publication number: GB2338438A
Application number: GB9912483A
Authority: GB
Inventors: Keith Thomas Skinner
Original assignee: Xcalibre Equipment Ltd
Current assignee: Xcalibre Equipment Ltd
Priority date: 1998-06-02
Filing date: 1999-06-01
Publication date: 1999-12-22
Also published as: GB9811702D0; GB9912483D0

Abstract

A rotary tool comprises a tubular drill 10 having a drive end 26 and a cutting end 14, the drive end 26 being detachably mounted on a driving element 28 whereby once the cutting end 14 of the drill 10 has become worn, the drill 10 can be removed from the driving element 28 and replaced by a fresh drill 10. The drill is secured by an 'O' ring 54 which expands when compressed between parts 30 and 32. A pilot drill is carried on a spider 16.

Description

1 ' el 1 A.UCA-008 A ROTARY TOOL 2338438 The invention relates to a rotary

tool. In particular, but not exclusively, the rotary tool is of a kind typically used by small builders and plumbers for drilling vent-holes in brick walls of buildings.

For some time, it has been known to use rotary tools in the form of tubular-drills having a cutting end and a drive end, the drive end being permanently secured to a driving element which can be rotated by an electric drill. The typical known type of tubular drill used by plumbers and small builders has tungsten carbide at its cutting end, typically in the form of brazed-on cutting tips. Once the cutting end has become completely worn away, the user 15 discards the entire drill and buys another. In more recent times, such tubular drills are being superseded by drills having a cutting end incorporating industrial diamonds, again, typically in the form of brazed-on cutting tips. Such drills are more expensive than the tungsten carbide type and the occasional user, such as a plumber, needs to balance the advantages of using a diamond tipped tool against the significantly higher cost of buying 20 such a tool in the first instance. Moreover, once the diamond tip has been worn away it is not cost effective to return the tubular drill to the manufacturer to be re-tipped and, therefore, the drill is discarded and it is necessary to incur the cost of an expensive replacement. The present invention is intended to help minimise the cost of replacing the worn drill so as to make the use of tubular drills, and primarily those incorporating diamonds, more attractive to the small user.

1 1 1 2 According to one aspect of the invention there is provided a rotary tool comprising a tubular drill having a drive end and a cutting end, the drive end being detachably mounted on a drivina element whereby once the cutting end of the drill has become worn, the drill 0 can be removed from the driving element and replaced by a fresh drill.

Although in the first instance a user needs to purchase the tool complete with tubular drill and drivina element, replacement of the drill does not involve replacement of the driving element thereby saving long term costs.

Preferably, the cutting end has cutting tips such as diamond tips thereon.

The drivina element and the tubular drill may be mounted one upon the other in spigot-like 0 manner. In such a case, the driving element preferably spigotally locates within the drive end of the drill.

The driving element is preferably adjustable in a radial direction once it has been located on the drill so as to grip a surface of the tubular drill. Where the driving element locates within the drive end of the drill, the driving element is preferably adjustable so as to grip an inside surface of the drill.

The radial adjustment may be provided by an elastomeric ring or ring of other suitable material which forms part of the driving element. The ring is preferably mounted between a fixed part and a movable part of the driving element. Once the driving element has been located on the drill, the movable part is moved towards the fixed part to deform the ring 3 causing it to move radially to grip the associated surface of the drill. The fixed and movable parts of the driving element preferably define a groove between them for the ring.

The fixed and movable parts may be movable relative to each other by means of one or more adjustment members which are preferably accessible from an exterior end surface of the driving element. Conveniently, the adjustment member or members may comprise one or more screws.

The surface of the drill gripped by the ring may have a depression therein, such as a circumferential groove, into which the ring deforms. In that way, instead of just simply gripping the said surface of the drill, the ring and the depression co- operate to form a mechanical interconnection to resist axial relative movement taking place between the driving element and the drill.

The driving element may include a spindle for location in a drill chuck. The spindle may is be located in a bore formed in the driving element. In order to secure the spindle in the bore, a transverse locking member such as a screw may be provided in the driving element.

In order to guide the drill initially into a surface to be drilled, the cutting end of the drill may be provided with a removable pilot drill. The pilot drill may be carried by a spider having legs locatable on the cutting end of the drill, for example in recesses. Preferably the spider has three legs angularly spaced at 120 degrees. The legs may extend from a hub in which the pilot drill is fitted.

1 ' 4 According to another aspect of the invention there is provided for a tubular drill having a drive end and a cutting end, a removable driving element for mounting drivably on the drive end whereby once the cutting end of the drill has become worn, the drill can be removed from the driving element and replaced by a fresh drill.

The drivine, element may have any of the features of the driving element referred to in the C> 0 aforesaid one aspect of the invention or any of the consistory clauses relating thereto.

According to yet another aspect of the invention there is provided for a tubular drill having 0 a drive end and a cutting end, the drill being detachably mountable on a driving element to form a rotary tool.

The tubular drill may have any of the features of the drill referred to in the aforesaid one aspect of the invention or any of the consistory clauses relating thereto.

A rotary tool in accordance with the invention will now be described by way of example with reference to the accompanying drawings in which:

Fa iO. 1 is a perspective view of the tubular drill and the drive element in accordance with the invention; Fig.2 is an axial cross-section through the drill shown in Fig. I; and 0 t> 1 Fi.

,.3 is a view on a larger scale showing the way ill which an 0-ring of the driving element expands to grip the inside surface of the tubular drill.

Referring to Figs. 1 and 2, a tubular drill 10 has a plurality of diamond impregnated tips 12 brazed to a cutting end 14. The cutting tips 12 stand slightly proud of the external diameter of the drill 10 to provide a working clearance for the drill as the tips penetrate a wall during drilling. The cutting end 14 is formed with three recesses 16, their centres being spaced apart by 120 degrees The recesses 16 receive three respective arms.18 extending radially from a central tubular hub 20 so as to form a spider indicated generally at 22. The hub 20 carries a short masonry drill bit 24. The arms 18 of the spider 22 are a close fit within the recesses 16 so that the spider 22 locates accurately in the drill 10 with the pilot drill 24 and the tubular drill 10 having the same axis of rotation indicated generally at A. The drill 24 is held in the hub 20 by means of a suitable screw 25.

The drill 10 has a driving end 26 in which is located a driving element 28. The driving element 28 comprises an annular inner part 30 and an annular outer part 32 which carries an hexagonal -section spindle 34 for mounting in a drill chuck (not shown). The inner part 30 of the driving element 28 has a cylindrical section 36 which is slidably located in a counterbore 38 formed in the outer part 32. The cylindrical section 36 extends from a 20 flange 40 of larger diameter, the cylindrical section 36 and the flange 40 meeting at a radius 42.

The inner part 30 is formed with four equispaced screw-threaded holes 44 (two only of which are shown) which align with four clearance holes 46 in the outer part 32. The 6 clearance holes 46 extend from counterbores 48. As shown in Fig.3 screws 50 pass through the clearance holes 46 and screw into the holes 44 in the inner part 30. Heads of 0 the screws 50 locate in the counterbores 48.

As shown in Figs.2 and 3, the inner and outer parts 30,32 form a groove 51 defined between the cylindrical section 36 of the inner part, the flange 40 and an opposing face 52 of the outer part. An 0-ring 54 locates in the groove 51. The outer diameter of the flange 40 and the outer diameter of a cylindrical section 56 of the outer part 32 are substantially identical and are spigotally located in the driving end 26 of the drill 10 as a close sliding fit. 10 The 0-ring 54 is also of similar outer diameter as it rests in the groove 5 1.

In use, the driving end 26 of the drill 10 is pushed on to the driving element 28 until the driving end abuts a small annular shoulder 58 on the outer part 32. The screws 50 are then tightened so as to squeeze the 0-ring 54 between the flange 40 of the inner part 30 and the face 52 of the outer part 32. The squeezing action causes the 0-ring 54 to deform outwardly and press hard against the inner surface of the drill 10 and the walls of groove 51. Tightening is continued so as to create a strong frictional grip between the driving element 28 and the drill 10 via the 0-ring 54. As shown in Fig.3, the inner surface of the drill 10 is formed with a shallow -roove 60 immediately opposite the 0- ring 54. As the 0-ring 54 deforms, part of the 0-ring enters the groove 60. In that way, the 0-ring 54 not only arips the drill 10 and the driving element 28 frictionally, but also provides a mechanical interlock between the drill 10 and driving. element 28 to prevent the driving element 28 becoming detached from the drill 10 if it becomes necessary to use considerable force to extract the drill 10 from a hole being formed.

7 To drill a hole in a wall, the spider 22 is first located as shown in Figs. 1 and 2 and the spindle 34 is mounted in a drill (not shown). It will be noted that the spindle 34 has an axis co-axia with the axis A. The pilot drill 24 is positioned at the place where the hole is to be drilled and the drill is operated to cause the pilot drill 24 to penetrate the wall. Penetration continues until the tips 12 form an annular groove in the wall and the drill 10 is then withdrawn. Next, the spider 22 is removed from the drill 10 and the tips 12 are re-positioned in the annular groove to enable drilling to be continued..

It will be noted that the spindle 34 is held in a boss 62 on the outer part 32 of the driving element 28. The spindle is secured within the boss by means of a suitable screw 64.

The drill 10 is formed with a plurality of apertures 66 to enable debris to escape during drilling of the hole. The section of the wall bounded by the annular groove cut by the tips 12 enters the hollow interior of the drill 10.

Once the tips 12 have become worn to the point where the drill is no longer effective, the screws 50 are loosened to relieve the load on the 0 -ring 54, the driving element 28 is withdrawn from the tubular drill 10 and a new tubular drill can then be fitted to the driving element. In that way, once the drill 10 is worn it is not necessary to discard the complete tool, driving element and all, but simply to replace the drill 10. In that way, the on-going costs resulting from the use of the drill are considerably less than if the whole drill along with its driving element were discarded as is the case with known tubular drills.

8 Although four cutting tips 12 are shown in Figs. 1 and 2, any suitable number of cutting tips can be provided.

Claims

9 Claims

1. A rotary tool comprising a tubular drill having a drive end and a cutting end, the drive end being detachably mounted on a driving element whereby once the cutting end of the drill has become worn, the drill can be removed from the driving element and replaced by a fresh drill.

2. A rotary tool according to claim 1, in which the driving element and the tubular drill are mounted one upon the other in spigot-like manner.

I. A rotary tool according to claim 2, in which the driving element spigotally locates within the drive end of the drill.

4. A rotary tool according to any preceding claim, in which a gripping part of the driving element is adjustable in a radial direction once it has been located on the drill so as to grip a surface of the tubular drill.

5. A Totary tool according to claim 4, in which the gripping part of the driving element is adjustable so as to grip an inside surface of the drill.

6. A rotary tool according to claim 4 or 5, in which the said gripping part of the driving element is a ring of flexible material such as an elastomeric ring.

0

7. A rotary tool according to claim 4, 5 or 6, in which the gripping part is mounted between first and second parts of the driving element, one of which is movable relative to the other.

1

8. A rotary tool according to claim 7, wherein once the driving element has been located on the drill, the movable part is moved towards the other part to deform the gripping part causing it to move radially to grip the associated surface of the drill.

9. A rotary tool according to claim 7 or 8, in which the first and second parts of the b driving element define a groove therebetween for the gripping part.

10. A rotary tool according to claim 7,8 or 9, in which the movable part is movable relative to the other part by means of one or more adjustment members.

11. A rotary tool according to claim 10, in which the or each adjustment member is accessible from an exterior end surface of the driving element.

12. A rotary tool according to claim 10 or 11, in which the adjustment member or members comprise one or rriore screws.

13. A rotary tool according to any of claims 4 to 12 in which the surface of the drill gripped by the gripping part has means thereon which cooperates with the gripping part.

14. A rotary tool according to claim 13, in which the means co-operable with the gripping part comprises a'depression in the said surface of the drill which receives the gripping part.

C C> 11

15. A rotary tool according to claim 14, in which the depression comprises a groove such as an annular groove.

16. A rotary tool according to any preceding claim, in which the driving element includes a spindle for location in a drill chuck.

17. A rotary tool according to claim 16, in which the spindle is located in a bore formed in the driving element.

18. A rotary tool according to claim 16 or 17, in which a transverse locking member such as a screw is provided in the driving element to lock the spindle to the driving element.

19. A rotary tool according to any preceding claim, in which the cutting end of the drill is provided with a removable pilot drill.

20.. A rotary tool according to claim 19, in which the pilot drill is carded by a spider having legs locatable on the cutting end of the drill.

21. A rotary tool according to claim 20, in which the spider has three legs angularly spaced at 120 degrees.

22. A rotary tool according to claim 20, in which the legs extend from a hub in which the pilot drill is fitted.

12

23. A rotary tool according to any preceding claim in which the cutting end of the tubular drill is provided with cutting tips which may be spaced apart.

24. A rotary tool substantially as described herein with reference to Figs. 1 to 3 of the drawings.

25. A driving element for a tubular drill, the drill having a drive end and a cutting end, the driving. element being detachably mountable on the cutting end of the drill to form a rotary tool whereby once the cutting end of the drill has become worn, the drill can be removed from the driving element and replaced by a fresh drill.

26. A driving element according to claim 25, in which the tubular drill is mountable on the driving element in a spigot-like manner.

27. A driving element according to claim 25 or 26, in which a gripping part of the driving element is adjustable in a radial direction once it has been located on the drill so as to grip a surface of the tubular drill.

28. A driving element according to claim 27, in which the -ripping part of the driving element is adjustable so as to grip an inside surface of the drill.

29. A driving element according to claim 27 or 28 in which the said gripping part of the driving element is a ring of flexible material such as an elastomeric ring.

30. A driving element according to claim 27, 28 or 29, in which the gripping part is. mounted between first and second parts of the driving element, one of which is movable relative to the other.

31. A driving element according to claim 30, wherein once the driving element has been located on the drill, the movable part is moved towards the other part to deform the gripping part causing it to move radially to grip the associated surface. of the drill.

32. A driving element according to claim 30 or 3 1, in which the first and second parts of the driving element define a groove therebetween for the gripping part.

33. A driving element according to claim 30, 31 or 32, in which the movable part is movable relative to the other part by means of one or more adjustment members.

34. A driving element according to claim 33, in which the or each adjustment member is accessible from an exterior end surface of the driving element.

35. A driving element according to claim 33 or 34, in which the adjustment member or members comprise one or more screws.

36. A driving element 'according to any of claims 27-35, in which the surface of the drill to be gripped has means thereon which co-operates with the gripping part.

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37. A driving element according to claim 36, in which the means cooperable with the gripping part comprises a depression in the said surface of the drill which receives the 0 gripping part.

38. A driving element according to claim 37, in which the depression comprises a groove such as an annular groove.

39. A driving element according to any of claims 25-38, in which a transverse locking member such as a screw is provided in the driving element to lock the spindle to the driving element.

40. A drivina element substantially as described herein with reference to the c accompanying drawings.

41 A tubular drill having a drive end and a cutting end, the drive end being detachably mountable on a driving element according to any of claims 25 to 40 to form a rotary tool.

42 A tubular drill according to claim 41 in which the drive end of the tubular drill spigotally locates on the driving element.

43 A tubular drill according to claim 41 or 42 in which the drive end has means thereon which is grippable by a gripping part of the driving element.

44 A tubular drill according to claim 43 in which the said means comprises a depression in the said surface of the drill which receives the gripping part.

A tubular drill according to claim 44 in which the depression comprises a groove such as an annular groove.

46 A tubular drill constructed and arranged substantially as described herein with reference to the accompanying drawings