GB2524768A

GB2524768A - Drilling aid and method of making a hole

Info

Publication number: GB2524768A
Application number: GB1405873.9A
Authority: GB
Inventors: Anthony Stapleton; Michael Hewitt
Original assignee: Airbus Operations Ltd
Current assignee: Airbus Operations Ltd
Priority date: 2014-04-01
Filing date: 2014-04-01
Publication date: 2015-10-07
Also published as: GB201405873D0

Abstract

The aid includes a drill target 1 with a target body 2 and one or more projections 3 projecting away from the body. The projection is for insertion into a pilot hole (301, Figure 3) provided in a substrate to be drilled and for holding the target securely in the pilot hole. The drill target includes one or more drill alignment surfaces 4-7, for aligning a drill relative to the pilot hole. The body of the target may include 2 to 8 portions connected by one or more breakable connecting portions 8. A method of producing a hole includes providing a substrate with a pilot hole and inserting the drill target projection into the hole, aligning a drill with the target and drilling into the target and pilot hole, thereby producing the hole and breaking the target. A set of drill targets includes first and second drill targets marked in accordance with different cutter sizes to be used.

Description

DRILLING AID AND METHOD OF MAKING A HOLE

FIELD OF THE INVENTION

100011 The present invention concerns drilling. More particularly, but not exclusively, this invention concerns drilling aids. The invention also concerns methods of producing holes.

BACKGROUND OF THE INVENTION

100021 The use of strip templates to locate a drilling apparatus relative to a substrate to be drilled is well-known to those skilled in the art particularly, but not exclusively, to those in the aviation industry. Such strip templates typically comprise a plurality of apertures within a strip, each aperture defining a place for the receipt of a part of drilling apparatus so that drilling can take place. There are certain circumstances, however, in which it is undesirable to use strip templates, for example, if the substrate to be drilled is very large. Also, by their very nature, strip templates are typically made in a strip shape, and this may not be desirable in certain circumstances, for instance if a strip will not fit into the space available, In this case, the applicant has found that it is possible to create a hole of a desired size and with a desired countersink by using a piloted drill bit (a drill bit with a small projection which is inserted into a pilot hole) to make a first (undersize) hole, and then ream the first (undersize) hole by hand to the correct size and correct countersink using a second drill bit. Such piloted drills may be prone to breakage (the pilot "nose" may be broken from the rest of the bit), and such drill bits may be difficult to sharpen, or may not be sharpened at all. Such piloted drill bits sometimes cannot be used with lubricant and therefore those drill bits cannot produce holes in a sufficiently reproducible manner.

10003] The present invention seeks to mitigate one or more of the above-mentioned problems. Alternatively or additionally, the present invention seeks to provide an improved drilling aid and/or method of producing holes,

SUMMARY OF THE INVENTION

[0004] In accordance with a first aspect of the present invention, there is provided a sacrificial drill target comprising a target body and one or more projections projecting away from the target body, for insertion into a pilot hole provided in a substrate to be drilled, and for holding the target securely in the pilot hole, the drill target comprising one or more drill alignment surfaces for aligning a drill relative to a pilot hole.

100051 The body of the target optionally comprises a plurality of body portions connected by one or more breakable connecting portions.

100061 For the avoidance of doubt, the body portions are typically not connected to one another other than by one or more connecting portions.

100071 The one or more connecting portions are arranged such that they are broken by the drilling process, thereby breaking the connections between the body portions. The breaking of the connecting portion(s) breaks the connection between body portions, thereby breaking the target into pieces. The pieces are typically removed, along with any drilling swarf, typically by the application of reduced pressure, for example, that provided by the application of a vacuum cleaner.

[0008] The target may comprise a connecting portion which is directly connected to more than I and optionally each of the body portions. Optionally, at least one connecting portion is located at or near the centre of the target, The target may comprise a connecting portion located at the centre of the target. The central connecting portion may be any suitable shape, for example, circular, annular or hexagonal. If the target comprises "n" body portions, then optionally the central connecting portion has "n" sides. For example, if the target has six body portions, the central connecting portion may optionally have six sides and is therefore generafly hexagonal in shape. The central connecting portion may optionally be provided with an aperture therein, [0009] The one or more connecting portions may typically be located at or near the centre of the target, Such an arrangement facilitates the simple and reliable breaking of the one or more connecting portions by a drill, "Near" in this context indicates that the connecting portion is located sufficiently close to the centre of the target so that the connecting portion is broken by the drilling process.

[0010] The connecting portion may comprise one or more arms, optionally attached to a central portion. An arm may connect the central portion of the connection portion to a body portion of the target. The size of the central connecting portion may be chosen such that it is slightly smaller than the diameter of the smallest drill bit with which the target will be used. The smallest drill bit will therefore destroy the central portion, breaking the arms connecting the connecting portion to the body portions.

100111 For the avoidance of doubt, "breaking" indicates that a connecting portion is destroyed, fragmented or otherwise made unviable as a connecting portion.

100121 The one or more drill alignment surfaces are optionally provided by the body of the target. One or more drill alignments surface may be provided by a perimeter of the body of the target. One or more of the body portions may provide a drill alignment surface, typically on an outer surface of one or more body portion. For example, the body may have a generally circular perimeter, sized to be received snugly within the end of a drill nosepiece of circular cross-section. The reception of the target within the nosepiece aligns the drill bit relative to the target, and therefore the pilot hole.

100131 The target body may have a generally circular perimeter, save for any gaps in the perimeter.

100141 One or more (optionally more than one and optionally each) body portion may extend radially from a connecting portion.

100151 One or more (optionally more than one and optionally each) body portion may generally comprise a sector of a circle, a wedge shape or a lobe.

100161 One or more spaces may be provided between adjacent body portions. At least one such space may be in the form of a channel, for example.

[0017] The drill target optionally comprises from 2 to 8 body portions, optionally 4 to 8 and optionally 4 to 6 body portions.

[0018] The target body may comprise one or more wali portions which generally extend away from a base. The base may be formed by one or more body portions.

Therefore, one or more (optionally more than one and optionally each) body portion may comprise a base portion and a wall portion extending away from the base portion. One or more of the wall portions may define a perimeter of the target. An external surface of one or more of the wall portions may slope inwardly, for example, by from 2 to 10 degrees; such an arrangement may facilitate the insertion of the wall portion into a drill nosepiece.

100191 One or more wall portions may extend inwardly from a perimeter of the target. The height of the wall inward of the perimeter may be less than the height of the wall at the perimeter. The height of the wall may taper downwardly with distance from the perimeter.

100201 One or more body portions may comprise a wall portion defining a perimeter of the target and one or more wall portions extending inwardly from the perimeter.

100211 One projection is optionally provided for insertion into a pilot hole. The projection is optionally generally cylindrical, and may optionally comprise one or more enlarged portions for engagement with the wall of a pilot hole. For example, the projection may comprise a portion of larger external diameter which, in use, engages with the wall of the pilot hole to inhibit removal of' the target and/or unwanted movement of the target. The projection may comprise a frusto-conical portion extending from the body to a cylindrical portion of the projection, 100221 The projection may be provided with one or more bore therethrough. The provision of a bore through the projection may facilitate easier drilling. The projection may optionally project from a connecting portion.

100231 The drill target should be formed from a material which does not interfere with the drilling process. The material should not blunt the drill bit in any way or exert excessive undesirable forces on the drill bit.

100241 The drill target may be made from a plastics material, such as nylon or polystyrene.

100251 The drill target is preferably one-piece, and is optionally formed by a moulding process, 100261 The projection may have a length of at least 5mm, optionally at least 10mm and optionally no more than 30mm.

[0027] If the projection is substantially circular in cross-section, the projection optionally has a greatest external diameter of at least 3mm, optionally at least 5mm and optionally no more than 10mm. The greatest external diameter of the projection will typically be very slightly greater than the diameter of the pilot hole into which the drill target is to be fitted, [0028] If the body has a generally circular perimeter, the body optionally has a greatest diameter of at least 10mm, optionally at least 20mm and optionally no more than 50mm.

100291 Tn accordance with a second aspect of the present invention, there is provided a set of drill targets comprising (i) a first drill target in accordance with the first aspect of the present invention, marked in accordance with a first cutter size to be used with the first target and (ii) a second drill target in accordance with the first aspect of the present invention, marked in accordance with a second cutter size to be used with the second target, the marking of the first target and the second target being mutually different.

[0030] The set of drill targets may comprise a group of first targets, marked in accordance with a first cutter size to be used with a first target. The set of drill targets may comprise a group of second targets, marked in accordance with a second cutter size to be used with a second target.

[0031] The set of drill targets may comprise a plurality of drill targets, each marked in accordance with a respective cutter size to be used with the respective target.

Each of said plurality of drill targets may be marked mutually differently, indicative of the different cutter size to be used with the respective target.

[0032] In accordance with a third aspect of the present invention, there is provided a method of producing a hole, the method comprising: providing a substrate to be drilled, the substrate comprising a pilot hole; providing a drill target comprising a target body and a projection projecting away from the target body;

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providing said pilot hole with the drill target by inserting the drill target projection into the hole; aligning a drill with said drill target; and drilling into the drill target and into the pilot hole, thereby producing a hole and breaking the target.

100331 The drill target is sacrificial -i.e. made unusable by the drilling process, typically being broken into more than one piece by the drilling process.

100341 When the target is in position ready for drilling, the body is optionally proud of the hole once the projection is inserted.

100351 Aligning a drill may comprise determining the position of the drill and, dependent on the position of the drill, moving the drill into the desired position.

100361 Aligning a drill may comprise moving the drill so that one or more surfaces of the drill abuts with, or is adjacent to, one or more surfaces of the drill target.

For example, aligning the drill may comprise moving the drill so that the drill target is snugly received within a drill nosepiece.

100371 The hole produced by drilling into the target is optionally of the desired size and desired countersink, with no further finishing required.

100381 The method may comprise optionally removing the broken target, optionally using low pressure.

100391 The method optionally comprises providing a lubricated drill bit, The drill bit is optionally not provided with a pilot projection (such pilot projections are typically small projections having a diameter of 5mm or so for insertion into a pilot hole).

100401 The hole created by said method is optionally countersunk.

100411 The hole created by said method is optionally a through-hole (one which extends through the entire thickness of a substrate), but may be a blind hole (a hole which does not extend through the entire thickness of a substrate). Likewise, the pilot hole may be a through-hole or a blind hole.

10042] The method may be of particular use on an aircraft component, where many holes (potentially of different sizes) are drilled.

100431 The method of the third aspect of present invention may comprise drilling first and second holes of mutually different diameters, the method comprising providing a first pilot hole with a first target, marked in accordance with a first cutter size to be used with the target; drilling into the first drill target with a cutter of the first cutter size, thereby producing a first hole; providing a second pilot hole with a second target, marked in accordance with a second cutter size to be used with the target; and drilling into the second drill target with a cutter of the first cutter size, thereby producing a second hole.

100441 Those skilled in the art will realise that the method features mentioned above need not be performed in the order stated. For example, the first and second pilot holes may be provided with the respective first and second drill targets before the first hole is drilled.

100451 It will of course be appreciated that features described in relation to one aspect of the present invention may be incorporated into other aspects of the present invention. For example, the method of the third aspect of the present invention may incorporate any of the features described with reference to the drill target of the first aspect of the present invention and vice versa,

DESCRIPTTON OF THE DRAWINGS

100461 Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings of which: Figure 1 A shows a perspective view of a drill target according to a first embodiment of the invention; Figure lB shows a plan view of the front of the drill target of Fig. 1A; Figure IC shows a cross-sectional view through the drill target of Figs. lÀ and 1B; Figure 2A shows a perspective view of a drill target according to a second embodiment of the invention; Figure 2B shows a plan view of the front of the drill target of Fig. 2A; Figure 2C shows a cross-sectional view of the drill target of Figs. 2A and 2B; and Figure 3 shows an exploded perspective view of a target in relation to a drill bit and drill nosepiece.

DETAILED DESCRIPTTON

100471 A first embodiment of a drilling target in accordance with a first aspect of the present invention will now be described by way of example only with reference to Figs. 1A, lB and 1C. The drilling target is denoted generally by reference numeral 1. The drilling target has a generally circular body 2 comprising four quadrant-shaped lobes 4, 5, 6, 7 which are connected by a connecting portion 8 having a general cross shape. The circular body 2 has a diameter of about 28.95mm and an essentially circular perimeter surface 20. Gaps 9, 10, 11, 12 are provided between adjacent lobes, meaning that the only connection provided between lobes is solely provided by connecting portion 8, This ensures that once the connecting portion 8 is destroyed by drilling, there is nothing connecting the lobes together, and the target is effectively destroyed. The target 1 comprises a projection 3 of generally tubular form, having an external diameter of 4,7mm (3/16 of an inch). The target 1 is moulded in one piece from nylon. The tubular nature of the projection means that it can be removed more easily by drilling than a solid cylindrical projection with no bore therethrough.

100481 The use of the target I will now be described in an example of a method in accordance with the present invention with reference to Figs. 1A, lB. 1C and 3. A blind pilot hole 301 of 3/16" diameter and 5mm depth is provided in a substrate 302 to be drilled. Such pilot holes are well known to those skilled in the art. Target 1 is presented to the pilot hole 301, with projection 3 being inserted into the pilot hole 301. The internal diameter of the pilot hcile 301 and the external diameter of the projection 3 ensure that the projection 3 fits snugly into the pilot hole 301, thereby holding the target 1 in place, ready for drilling. The projection 3 is located centrally relative to the body 2, and the projection 3 extends from the body 2 by about 4mm and therefore the entire length of the projection is received in the 5mm deep pilot hole 301. The front face of body 2 contacts the substrate 302 to be drilled. A drill (a Luebbering KL-56) denoted generally by reference numeral 303 comprising a nosepiece 304 having an essentially circular cross-section is brought-up to the target 1. The nosepiece 304 is generally cylindrical in shape and has an essentially circular cross-section. The internal diameter of the end 305 of the nosepiece is about 29mm, and therefore the target 1 fits snugly within the aperture 306 at the end 305 of the nosepiece 304, the essentially circular perimeter surface 20 of target body 2 contacting the internal surface of the end 305 of the nosepiece. The nosepiece 304 is therefore brought up to the target 1 so that the target 1 is located in the end 305 of the nosepiece 304. This location of the nosepiece 304 relative to the target 1 positions the drill 303 ready for use. The drill bit 307 is a lubricated, non-piloted drill bit (Klenk GmbH, Germany), and has a cutting size of 5/16" (7.9mm) which is centred on the centre of the target 1. The drill bit 307 is advanced in a direction shown as D in Fig. 1 C and is brought into contact with the target 1, and the drill bit 307 drills through the soft nylon material of the target I with ease. The cutting diameter of the drill bit 307 ensures that the connecting portion 8 is broken by the drilling process, thereby removing any physical connection between lobes 3, 4, 5, 6. Disconnected lobes 3, 4, 5, 6 are removed from the drilling site, along with any swarf, by the application of a low pressure, for example, by using a vacuum, as is well-known to those skilled in the art, The hole drilled by the bit 307 is of the desired diameter because the bit 307 used is a lubricated bit which reproducibly produces holes of a desired size. The desired countersink is produced by providing a limit to the amount of travel of the drill bit 307. This is often provided by a calibrated stop mechanism as will be known to those skilled in the art. The use of the target 1 facilitates the production of holes of the desired size without hand reaming and without the use of a strip template.

[0049] Another example of an embodiment of a target in accordance with the present invention will now be described with reference to Figures 2A, 2B and 2C. Figure 2A is a perspective view of the front of the target, Figure 2B is a plan view of the front of the target (with features in dotted lines being present on the rear of the target) and Figure 2C is a sectional view through the target. The target is denoted generally by reference -10 -numeral 101, and comprises a body 102 from which projects a projection 103. The projection 103 comprises a frusto-conical base portion 103b which tapers from a wide part having an external diameter of 5.1mm adjacent to body 102 to a narrower part having an external diameter of 4.7mm remote from the body 102. This frustoconical portion provides positive engagement with the walls defining a pilot hole of diameter 4.7mm. The projection 103 further comprises a cylindrical portion I 03a of external diameter of 4,7mm, The body 102 comprises six body portions in the form of wedge-shaped lobes 1 04-109, connected by a substantially hexagonal connecting portion 116.

There are gaps 110-115 between adjacent lobes 104-109 such that the only physical connection between the lobes is provided by connecting portion 116. If we consider connecting portion 116 to be a hexagon, the maximum dimension of the connecting portion 116 is the across corners dimension of the hexagon of 7.7mm (19/64"). Any drill bit having an effective cutting diameter of greater than 7.7mm can then be used to fragment the connecting portion 116 and break the physical connections between lobes 104-109. Tn this case, a drill having a cuffing diameter of 5/16" or more will effectively fragment the connecting portion 116. As for target 1, target 101 has a generally circular perimeter of diameter of 28,9-29,0mm, Each lobe 104-109 is provided with a wall 204- 209. Each wall has an outer portion 204a-209a which assists in defining the outer perimeter of the target. The outer portions 204a-209a deviate inwards slightly from the vertical by about 3 degrees. This assists in facilitating the movement of the drill nosepiece over the target. Each wall 204-209 has two inwardly projecting portions 204b- 209b and 204c-209c, These portions provide strength to the target and inhibit unwanted target deformation. The height of the inwardly projecting portions 204b-209b and 204c- 209c decreases with distance from the perimeter of the body 102.

100501 The target 101 is used in essentially the same way as target 1, although the projection 103 provided for target 101 is longer than that used for target 1 and therefore the pilot holes for target 101 needs to be deeper than 5mm (typically more than 12mm is required for target 101).

100511 Whilst the present invention has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in -11 -the art that the invention lends itself to many different variations not specifically illustrated herein. By way of example only, certain possible variations will now be described.

[0052] The examples above illustrate the use of the drill target to produce holes in aircraft components. The drill target may be used to produce holes in other substrates.

[0053] The examples above illustrate the use of different colours to differentiate between different cutter sizes which are to the used with respective targets. Other types of markings (such as numbers) could be used to differentiate between the cutter sizes which are to be used with respective targets.

100541 The examples above describe the alignment of the drill by providing a target substantially the same diameter as the nosepiece, the target being received snugly within the nosepiece of the drill. The drill may be aligned relative to the target in different ways. For example, the drill target may be provided with one or more surfaces for alignment with one or more surfaces of a drill bit, such as the cutting tip. For example, the drill target may be provided with a frusto-conical surface for receiving and positioning a cutting tip of a drill bit.

[00551 Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth, Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. Tt will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and may therefore be absent, in other embodiments,

Claims

-12 -CLAIMS1, A sacrificial drill target comprising a target body and one or more projections projecting away from the target body, for insertion into a pilot hole provided in a substrate to be drilled, and for holding the target securely in the pilot hole, the drill target comprising one or more drill alignment surfaces for aligning a drill relative to a pilot hole.
2. A drill target according to claim 1 wherein the body of the target comprises a plurality of body portions connected by one or more breakable connecting portions.
3. A drill target according to claim 1 or claim 2 comprising a connecting portion which is directly connected to each of the body portions.
4. A drill target according any preceding claim wherein at least one connecting portion is located at or near the centre of the target.
5, A drill target according to claim 4 wherein the target a connecting portion located at the centre of the target.
6. A drill target according to claim 5 wherein the target comprises "n" body portions, and the central connecting portion has "n" sides.
7. A drill target according to any preceding claim comprising one or more arms attached to a central portion.
8, A drill target according to claim 7 wherein each arm connects the central portion of the connection portion to a respective body portion of the target.
9. A drill target according to any preceding claim wherein the one or more drill alignment surfaces are provided by the body of the target.
10. A drill target according to claim 9 wherein one or more drill alignment surfaces are provided by a perimeter of the body of the target.
11. A drill target according to claim 9 or claim 10 wherein one or more of the body portions provide a drill alignment surface.

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12. A drill target according to any of claims 9 to 11 wherein the body has a generally circular perimeter, sized to be received snugly within the end of a drill nosepiece of circular cross-section.
13. A drill target according to any preceding claim wherein one or more (optionally more than one and optionally each) body portion extends radially from a connecting portion.
14. A drill target according to any preceding claim wherein one or more (optionally more than one and optionally each) body portion generally comprises a sector of a circle, a wedge shape or a lobe.
15. A drill target according to any preceding claim wherein one or more spaces are provided between adjacent body portions.
16. A drill target according to claim 15 wherein at least one space is in the form of a channel.
17. A drill target according to any preceding claim comprising from 2 to 8 body portions.
18. A drill target according to any preceding claim wherein the target body comprises one or more wall portions which generally extend away from a base.
1 9. A drill target according to claim 1 8 wherein the base is formed by one or more body portions, one or more body portion comprising a base portion and a wall portion extending away from the base portion.
20. A drill target according to claim 19 wherein one or more of the wall portions define a perimeter of the target.
21. A drill target according to any of claims 18 to 20 wherein an external surface of one or more of the wall portions slopes inwardly.
22. A drill target according to any of claims 18 to 21 wherein one or more wall portions extend inwardly from a perimeter of the target.
23. A drill target according to claim 22 wherein the height of the wall inward of the perimeter is less than the height of the wall at the perimeter.
24. A drill target according to claim 23 wherein the height of the wall tapers downwardly with distance from the perimeter, -14 -
25. A drill target according to any preceding claim wherein one projection is provided for insertion into a pilot hole, wherein the projection is generally cylindrical, and comprises one or more enlarged portions for engagement with the wall of a pilot hole.
26. A drill target according to claim 25 wherein the projection is provided with one or more bore therethrough.
27. A set of drill targets comprising (i) a first drill target in accordance with the first aspect of the present invention, marked in accordance with a first cutter size to be used with the first target and (ii) a second drill target in accordance with the first aspect of the present invention, marked in accordance with a second cutter size to be used with the second target, the marking of the first target and the second target being mutually different.
28. A method of producing a hole, the method comprising: providing a substrate to be drilled, the substrate comprising a pilot hole; providing a drill target comprising a target body and a projection projecting away from the target body; providing said pilot hole with the drill target by inserting the drill target projection into the hole; aligning a drill with said drill target; drilling into the drill target and into the pilot hole, thereby producing a hole; and breaking the target.
29. A method according to claim 28 comprising aligning a drill may comprise moving the drill so that one or more surfaces of the drill abuts with, or is adjacent to, one or more surfaces of the drill target.
30. A method according to claim 29 wherein aligning the drill comprises moving the drill so that the drill target is snugly received within a drill nosepiece,