GB2453621A

GB2453621A - Visual drilling depth indicator

Info

Publication number: GB2453621A
Application number: GB0814770A
Authority: GB
Inventors: Anthony Pugh
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-08-13
Filing date: 2008-08-13
Publication date: 2009-04-15
Anticipated expiration: 2028-08-13
Also published as: GB0814770D0; GB2453621B; WO2010018372A1

Abstract

A device for determining when a drilled hole has reached a pre-set depth, comprises a light emitting device 1, a power source, and a control switch attached to the body of a drilling machine 2. The device projects at least one visual reference mark 5 on a drilling tool 4 at a pre-set distance from a drill tip 8 equal to the required hole depth 9. The reference mark advances towards a workpiece 10 during drilling, and indicates that the pre-set depth has been achieved when it coincides with the surface of the workpiece. Preferably, the position of the light mark on the tool can be varied. A computing device 13 may be provided to convert the movement of the light source into a measurement displayed on a visual display 14. A mirror (15, fig 3) reflecting a continuously pulsed laser beam may be used to produce a number of visual graduations on the tool.

Description

Drilling-depth indicator for a drilling device The invention relates to a device that indicates to the operator when a drilled hole has reached a pre-determined depth in the drilled material.

In some circumstances it is important that a hole is not drilled too deeply, for example in a concrete floor where a damp-proof-membrane could be holed by the drill. In the construction industry, drilling over-deep holes wastes time and increases wear on the drilling-tool and drilling machine.

Simple mechanical depth-gauges are commonly supplied with electric hand-drills and can be used to pre-set the depth of a drilled hole. Typically they use an adjustable rod that projects toward the work-piece in the same axis as the drilling-tool and in use the rod is backed-off a set distance from the work-piece surface equivalent to the depth of hole required.

They have disadvantages in that the rod's point of contact with the work-piece is off-set from the point of drilling so will only give a true indication of hole-depth if the work-piece is perfectly flat and perpendicular to the drilling-tool, and due to the off-set point of contact they are not suitable for use when drilling angled holes and are difficult to use in tight corners or areas of limited space.

It is the object of this invention to provide a drilling-depth indicator that indicates the drilling-depth on the actual drilling-tool so is clearly visible to the operator during the drilling operation and can be used on irregular work-pieces and for drilling angled holes, and uses a method that does not require contact with the work-piece surface so can be used in confined areas or anywhere that the hole can be drilled.

Accordingly, this invention provides a drilling-depth indicator, that includes a light-emitting device a power-source and control switch attached to the body of a drilling machine, that projects a visual reference mark on the drilling-tool at a pre-set distance from the drill-tip that is equal to the required hole-depth, the reference mark then advances towards the work-piece surface during drilling and when coinciding with the surface of the work-piece indicates that the pre-determined hole-depth has been achieved.

Preferably the light emitting device is a laser that produces a light-beam in the visible-light spectrum and has a focusing element that shapes the projected Laser-beam into a small dot or other shape that produces a clearly visible and defined mark on the drilling-tool, but it may also be a focused bulb or light-emitting-diode (LED) or a semi-conductor device that transmits a light-beam down an optical fibre. The colour of the light-mark may be varied to give optimum visibility according to the operating conditions.

It is also preferable that the light-emitting device is mounted on the drilling machine body, but will function equally well if mounted on or in a removable part of a drilling-machine such as a side steadying handle, or a collar or strap that is clamped to the drilling machine body, or even attached to the drill body by a temporary method such as a Velcro or adhesive patch or in the case of iron-cased drilling machines by a magnetic clamp, provided it stays in alignment with the drilling-tool during the drilling process.

A preferred embodiment of the invention will now be described with reference to the accompanying drawings in which: FIGURE 1 shows a side view of a hand drilling machine and drilling-depth indicator.

FIGURE 2 shows a hole drilled to the pre-set depth.

FIGURE 3 shows an alternative arrangement of projecting the laser-beam.

With reference to Figure 1, a laser pointing module (1) is mounted by a pivot point on the body of a hand drilling machine (2) such that its emitted light-beam (3) is axially aligned to project a moveable visible reference mark on the surface of the drilling-tool (4) at a pre-set position (5). The laser pointing module is powered by the battery (6) via the on-off switch (7). If the distance between the projected light-mark (5) and the drill-tip (8) is set to be equivalent to the depth of the hole required (9), a visual indication that the pre-set hole depth is achieved when the projected light-mark on the drilling-tool coincides with the surface of the drilled work-piece (10) as shown by Figure 2. The rotation of the drilling-tool does not affect the visibility of the light-mark.

By rotating the body of the laser pointing device about its pivot point, the included angle betwepn the drill axis and the laser beam (11) is altered, and the visible reference mark (5) moyed along the body of the drilling tool (4) to allow setting for other hole depths.

The rotational movement of the laser pointing module (11) can be coupled to a rotary encoding device (12) and the resultant electrical signal used as an input to a computing device such as a micro-processor (13) which is programmed to convert the angular rotation into a linear measurement and display the measurement on an LED or LCD display (14) for direct read-out of the hole setting depth.

In the embodiment previously described the laser light-beam is projected directly at the drilling-tool, and the body of the laser pointing device is rotated to vary the position of the light-mark on the tool-body, but for equal effect, the beam of the laser pointing device could be projected towards an inclined mirror or lens (15) which reflects or deflects the light-mark towards the drilling-tool, as depicted in Figure 3.

If the mirror or lens is rotated about its mounting point the light-mark is moved along the drilling-tool, and if the mirror or lens is moved linearly closer to, or farther from, the light-emitting device, the light-mark is similarly moved along the body of the drilling-tool body.

There is an advantage in a linear movement in that the hole-depth can be read as a linear measurement without the need of angular to linear conversion. This linear movement can be sensed and connected to an analogue-to-digital converter for input to the computing device and visual display. A set-zero switch would be beneficial in setting the drilling-depth from the display by using the following procedure; Firstly, the light-beam is projected to the drill-tip and the display set to zero by the switch; Secondly, the light-mark is backed-off along the drilling-tool to the required distance that can be read-off the display in direct units, for example inches or millimetres.

With reference to Figure 3, if the mirror (15) is continuously rotated as the laser beam is pulsed at pm-set timing intervals any number of visual reference marks can be projected onto the drilling-tool, these could be timed to produce a number of visible marks, or graduations on the surface of the drilling-tool and so give a direct indication of drilling-depth as the drilling process proceeds.

Claims

I. A device for determining when a drilled hole has reached a pre-set depth, that includes a light-emitting device a power-source and control switch attached to the body of a drilling machine, that projects at least one visual reference mark on the drilling-tool at a pre-set distance from the drill-tip equal to the required hole-depth, the reference mark then advances towards the work-piece during the drilling operation and when coinciding with the surface of the work-piece indicates that the pre-detennined hole-depth has been achieved.
2. A device as claimed in claim 1, wherein the light-emitting device projects a plurality of visual marks on the body of the drilling-tool
3. A device as defined in claim I, wherein the position of the light-mark on the drilling element can be varied along the axis of the drilling element.
4. A device as defined in claim 3, wherein the position of the light-mark on the drilling element can be varied by rotating the body of the laser pointing device about its pivot point.
5. A device as defined in claim 3, wherein the position of the light-mark on the drilling element can be varied by reflecting the light-beam by a moveable mirror.
6. A device as defined in claim 3, wherein the position of the light-mark on the drilling element can be varied by deflecting the light-beam by a moveable lens or prism.
7. A device as defined in claim 3, wherein the position of the light-mark can be varied by sending the light-beam down an optical fibre which can itself be moved in relation to the drilling element.
S. A device as defined in claim 4, 5,6 or 7, wherein physical movement of the light-emitting device, mirror, lens, prism or optical fibre is coupled to an encoder and the resultant electrical signal used as an the input to an electronic computing device configured to convert the movement into a linear measurement which is then displayed visually by means of a visual display.
9. A device as claimed in claim 5, wherein the mirror is continuously rotated as the laser beam is pulsed at a pie-set timing interval to produce a number of visual graduations on the drilling-tool.
10. A drilling-depth indicator substantially as herein described and illustrated in the accompanying drawings.