GB2523779A

GB2523779A - Back spot-facing tool

Info

Publication number: GB2523779A
Application number: GB1403837.6A
Authority: GB
Inventors: Colin Sharples
Original assignee: Airbus Operations Ltd
Current assignee: Airbus Operations Ltd
Priority date: 2014-03-05
Filing date: 2014-03-05
Publication date: 2015-09-09
Also published as: GB201403837D0

Abstract

A back spot-facing tool for cutting a spot-face in a workpiece comprising an arbor 2 insertable through a hole about which the spot face is to be cut, a cutting depth control element 4 positionable against the workpiece, and a cutter 3 mountable to the arbor. The cutter having two portions, the first portion 16 configured to slide in an axial direction relative to the depth control element towards and into a workpiece during cutting, the second portion 17 configured to engage the cutting depth control element when a predetermined depth of cut has been reached to prevent further movement of the cutter in an axial direction. There are two other aspects to the invention, the first is for a back spot-facing tool kit comprising the tool described above, with a plurality of cutter each dimension to provide a different depth of cut and the second is for a back spot-facing tool kit comprising the tool described above, where there are a plurality of cutting depth control elements each having an associated cutter, each control element and its cutter being dimensioned so as to cut a different spot-face diameter.

Description

BACK SPOT-FACING TOOL

Background to the invention

The present invention relates to a back spot-facing tool.

A spot face is a machined feature in which a region or spot' on a workpiece is faced in order to provide a smooth and accurately located surface. This procedure is especially carried out on workpieces that are cast or forged as the surface of such workpieces can have a relatively high level of surface roughness. A spot-face is a io smooth, flat, accurately located region that stands in distinction to the surrounding surface.

A spot-face is typically required in a region around a bolt hole against which the head of a bolt will sit. The spot-face is formed by machining a shallow counterbore that is deep enough to remove any irregularities and so make the surface flat.

In aircraft applications, a spot-face must to be cut around each hole in a spar through which bolts are inserted for attachment of the top and bottom skin of the wing of an aircraft to the spar. This often requires a back spot-facing technique to be performed. In this instance, the cutter is mounted to an arbor or mandrel that is positioned so that it extends through an aligned bolt hole in both the wing skin and the spar. The arbor is mounted in the chuck of a drill and the operator then operates the drill whilst drawing the arbor, and the cutter mounted thereto, in an axia' direction towards him from a position outside of the wing skin, to cut a spot face in the spar on the other side of the wing skin.

It will be appreciated that a problem with the above-identified approach is that the operator is working blind, as he cannot see the spot-face as it is being cut. He must therefore rely on an assistant to notify him when the spot face has been cut to a sufficient depth. Then, on receiving a signal from the assistant, the operator must quickly stop cutting by switching off the drill and/or by pushing the arbor in the opposite direction so that the cutter no longer makes contact with the workpiece.

Failure to respond quickly can result in the spot face becoming too deep resulting in the spar becoming unusable. It will also be appreciated that controlling the depth of cut 3 manually in this way does not produce a consistent depth of cut to any of the spot faces and is prone to inaccuracy and may lead to spot faces being cut that are either too shallow or too deep.

Summary of the Invention

According to the invention, there is provided a back spot-facing tool for cutting a spot-face in a workpiece, the tool comprising an arbor insertable through a hole about which the spot face is to be cut, a culling depth control element positionable against the workpiece and a cutter mountable to the arbor and having a first portion configured to slide in an axial direction relative to the depth control element towards and into a workpiece during cutting, wherein the cutter comprises a second portion configured to engage the cutting depth control element when a predetermined depth of cut has been reached to prevent further movement of the cutter in an axial direction.

In a preferred embodiment, the cutting depth control element comprises a body portion having a face positionable against a workpiece adjacent to a hole about which a spot-face is to be cut and, an opening configured to slideably receive the first portion of the cutting element therethrough, the second portion of the cutting element having a dimension larger than the opening so that the second portion contacts the body portion when a predetermined depth of cut has been reached to prevent further axial movement of the cutting element.

Preferably, the opening is cylindrical in shape and has an axis that extends perpendicular to a plane in which the face of the body portion extends. The cylindrically shaped opening is spaced from said plane.

The body portion may comprise a handle that may be configured to extend away from said plane at an angle.

The first and second portions of the cutting element are preferably integral with each other. In one embodiment, the second portion comprises a collar or flange having a shoulder that extends radially from the first portion and which engages the body portion around a periphery of the opening when a predetermined depth of cut has been reached.

According to another aspect of the invention, there is provided a back spot-facing tool kit for cutting a spot-face in a workpiece, the tool comprising an arbor insertable through a hole about which the spot face is to be cut, a cutting depth control element positionable against the workpiece and a plurality of cutters, each cutter being dimensioned so as to provide a different depth of cut, each cutter being mountab'e to the arbor and having a first portion configured to slide in an axial direction relative to the depth control element towards and into a workpiece during cutting, wherein each cutter comprises a second portion configured to engage the cutting depth contr& element when a predetermined depth of cut has been reached to prevent further movement of the cutter in an axial direction.

rn According to another aspect of the invention, there is provided a spot-facing tool kit for culling a spot-face in a workpiece, the tool comprising an arbor insertable through a hole about which the spot face is to be cut and a plurality of cutting depth control elements each having an associated cutter, each culling depth control element and its associated cutter being dimensioned so as to cut a different spot-face diameter, wherein each cutter is mountable to the arbor and has a first portion configured to slide in an axial direction relative to its depth contrel element towards and into a workpiece during cutting, each cutter comprising a second portion configured to engage the cutting depth control element when a predetermined depth of cut has been reached to prevent further movement of the cutter in an axial direction.

In one embodiment, each cutting depth control element has an associated arbor so that the kit is made up of a p'urality of cutting depth control elements, a plurality of cutters and a plurality of arbors.

Brief Description of the Drawings

Embodiments of the invention will now be described, by way of example only, and in which: FIGURE 1 is a perspective view of a back spot-facing tool according to an embodiment of the invention; o FIGURE 2 is an exploded side elevation of the back spot-facing tool shown in Figure 1; FIGURE 3 is a side elevation of the the back spot-facing tool of Figure 1 in an assembled state with the arbor inserted through a hole in a workpiece and with the cutter positioned ready to initiate cutting of a spot-face; and FIGURE 4 is the same enlarged side elevation of Figure 3, but after the spot face has been cut to its maximum predetermined depth.

Detailed Description of the Drawings

With reference to the drawings, there is shown a back spot-facing tool 1 according to an an embodiment of the invention. The tool 1 comprises three parts namdy, a mandrel or arbor 2, a cutter 3 and a cutting depth control dement 4.

The arbor 2 is inserted throngh a hole 5 in a workpiece, such as in a rib 6 and skin 7 of an aircraft wing (not shown), so that it extends in an axial direction (A-A' in Figures 2 to 4) through the hole 5. The cutter 3 is removably but rigidly attachaNe to an end 8 of the arbor 2 in a conventional way so that cuffing teeth 9 formed on an end of rn the cutter 3 face the rib 6. The opposite end 10 of the arbor 2 is provided with cooperating elements ii that cooperate with the chuck of a drill (not shown) to enable it to be driven rotatably.

Prior to attachment of the cutter 3 to end 8 of the arbor 2, a ring-shaped opening 12 formed in the cutting depth control element 4 is slid over the end 8 of the arbour 2. The cutting depth control element 4 has a body 13 with a rib engaging face 14 and a handle i, which extends away from the workpiece engaging face 14 at an angle to enable an assistant to hold the cutting depth control element 4 in position with its rib engaging face 14 located against the surface of the rib 6 surrounding the hole 5. A suitable angle for the handle 15 maybe in the region of 450 from the plane occupied by the rib engaging face 14. This will enaNe an assistant to easily use the todl 1 in areas where access is restricted.

The cutter 3 has a first portion 16 dimensioned so that it will slide freely into the ring-shaped opening 12 in an axial direction A-A and also so that it will rotate relative thereto when the arbor 2 is rotatably driven. The cutter 3 also has a second portion or collar 17, which is larger than the ring-shaped opening 12 so that, once an underside surface 18 of the collar 17 contacts the body 13 in a region surrounding the periphery of the ring-shaped opening 12, no further movement of the cutter 3 in an axial direction A-A towards the rib 6 is possible.

It will be appreciated that the cutting depth control element 13 and the cutter 3 may be dimensioned so as to provide a predetermined depth of cut into the rib 6. A consistent and repeatable cut is always produced for every spot face, as the collar 17 contacts the cutting depth control álement 13 when a predetermined depth of cut for the spot-face has been reached. It is envisaged that the diameter of the first portion 16 of the cutter 3 can be made so that it has the ability to flex to a limited extent. This enables a spot-face to be produced on tapered surfaces.

Although only one cutter 3 may be provided, it is also envisaged that a single cutting depth control element 4 may be provided with a plurality of cutters 3, each of which have a first portion 16 of a different length to enable spot-faces of different depths to be cut depending upon different requirements. The tool 1 may therefore be provided as a kit comprising a cutting depth control element 4 and a range of cutters 3.

Alternatively or additionally, a kit may comprise a plurality of cutting depth control rn elements 4. The ring-shaped opening 12 in each cutting depth control element 4 of the kit may have a different diameter to receive a corresponding cutter 3, also forming part of the kit. This enables spot-faces of different diameters to be cut. Each cutting depth control element 4 maybe provided with its own arbor. Each arbor may have a different diameter for insertion through differently sized holes about which a spot-face is to be cut.

Tt will be appreciated that the spot-face tool 1 according to the present invention no longer relies on communication between the operators and so the depth of cut will remain consistent as further axial movement of the cutter 3 into the rib 6 is prevented once contact between the collar 17 and the cutting depth control element 13 has been made.

Many modification and variations of the invention falling within the terms of the following claims will be apparent to those skilled in the art and the foregoing description should be regarded as a description of the preferred embodiments of the invention only.

Claims

Claims 1. A back spot-facing tool for cutting a spot-face in a workpiece, the tool comprising an arbor insertable through a hole about which the spot face is to be cut, a cutting depth contr6l element positionable against the workpiece and a cutter mountable to the arbor and having a first portion configured to slide in an axia' direction relative to the depth control element towards and into a workpiece during cutting, wherein the cutter comprises a second portion configured to engage the cutting depth control element when a predetermined depth of cut has been reached to prevent further movement of the cutter in an axial direction.
2. A back spot-facing tool according to claim 1, wherein the cutting depth control element comprises a body portion having a face positionable against a workpiece adjacent to a hole about which a spot-face is to be cut and, an opening configured to slideably receive the first portion of the cutting element therethrough, the second portion of the cutting element having a dimension larger than the opening so that the second portion contacts the body portion when a predetermined depth of cut has been reached to prevent further axial movement of the cutting element.
3. A back spot-facing tool according to claim 2, wherein the opening is cylindrical in shape and has an axis that extends perpendicular to a plane in which the face of the body portion extends.
4. A back spot-facing tool according to claim 3, wherein the cylindrical shaped opening is spaced from said plane.
A back spot-facing tool according to claim 2, wherein the body portion comprises a handle.
6. A back spot-facing tool according to claim 5, wherein the handle is configured so that it extends away from said plane at an angle.
7. A back spot-facing tool according to any preceding claim, wherein the first and second portions of the cutting element are integral with each other.
8. A back spot-facing tool according to any preceding claim, wherein the second portion comprises a coflar or flange having a shoulder that extends radially from the first portion and which engages the body portion around a periphery of the opening when a predetermined depth of cut has been reached.
9. A back spot-facing tool kit for cutting a spot-face in a workpiece, the tool comprising an arbor insertable through a hole about which the spot face is to be cut, a cutting depth control element positionable against the workpiece and a plurality of cutters, each cutter being dimensioned so as to provide a different depth of cut, each cutter being mountable to the arbor and having a first portion configured to slide in an axial direction rolative to the depth control element towards and into a workpiece during cutting, wherein each cutter comprises a second portion configured to engage the cutting depth control element when a predetermined depth of cut has been reached to prevent further movement of the cutter in an axial direction.
10. A back spot-facing tool kit for cutting a spot-face in a workpiece, the tool comprising an arbor insertable through a hole about which the spot face is to be cut and a plurality of cutting depth control elements each having an associated cutter, each cutting depth control element and its associated cutter being dimensioned so as to cut a different spot-face diameter, wherein each cutter is mountable to the arbor and has a first portion configured to slide in an axial direction rálative to its depth control element towards and into a workpiece during cutting, each cutter comprising a second portion configured to engage the cuffing depth control element when a predetermined depth of cut has been reached to prevent further movement of the cutter in an axial direction.
ii. A back spot-facing tool kit according to claim 0, wherein each cutting depth control element has an associated arbor.
12. A back spot-facing tool substantially as hereinbefore described with reference to the accompanying drawings.