WO2004026536A1

WO2004026536A1 - Scribing apparatus

Info

Publication number: WO2004026536A1
Application number: PCT/GB2003/003984
Authority: WO
Inventors: Gary Paul Nicholls
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-09-17
Filing date: 2003-09-17
Publication date: 2004-04-01
Anticipated expiration: 2005-03-17
Also published as: GB0507567D0; GB2409426B; GB2409426A; GB0221559D0; AU2003271845A1

Abstract

Scribing apparatus (10) for marking a cutting line on a board or other workpiece, so as to reproduce on the workpiece the profile or undulations of a wall or other architectural item against which the workpiece, when cut along the line, will fit, comprises a bar member (11) on which is slidably mounted a housing (16) for a scribe element (17), the bar having at one end a roller member (12) for contact with a wall and at the other end a point formation for contact with a profiled architectural item. Preferably, the bar has an upturned distal end region (14) terminating in a chisel edge (15), the chisel edge being in the same plane as the scribe element, the plane being parallel with and spaced apart from the bar member. The scribe element is preferably double-ended.

Description

Scribing Apparatus

This invention relates to scribing apparatus, that is, apparatus for marking a cutting line on a board or other workpiece so as to reproduce on the workpiece the profile or undulations of a wall or other architectural item against which the workpiece, when cut along the line,

Scribing apparatus of the type described is the subject of GB2251401A and WO89/09119. The apparatus described in GB2251401 A has a marking stylus slidably supported in a body member having a nylon foot for engaging a wall surface at one end, the body member terminating in converging surfaces defining a point at the other end for following the contours of a skirting board or dado rail. The apparatus described in WO89/09119 has a pencil holder slidably mounted on a multi-angled bar having a right-angled plate at one end for contact with a wall and a probe formation at the other end for following more accurately the intricate contours of a protrusion or cavity. Neither of the prior art proposals, however, provides scribing apparatus which enables cutting lines to be marked on a workpiece with speed and accuracy, irrespective of the undulations of a wall surface or the complexity of an architectural item the profile of which is to be reproduced on the workpiece.

According to one aspect of the present invention, scribing apparatus comprises a bar member on which is slidably mounted a housing for a scribe element, the bar having at one end a roller member for contact with a wall.

The roller member, which is preferably a wheel mounted about an axis of rotation orthogonal to the longitudinal axis of the bar member and in the same plane as the scribe element, the plane being parallel with and spaced apart from the bar member, is easier to use than conventional feet or plates especially on rough walls and furthermore does not leave a mark or trace on the wall surface. As to the diameter of the roller member, it should neither be so large that small protrusions on the wall surface are magnified nor so small that insignificant depressions or cracks in the wall surface are replicated on the workpiece. According to another aspect of the invention, scribing apparatus comprises a bar member on which is slidably mounted a housing for a scribe element, the bar having at one end a follower member for contact with a wall and at the other end a point formation for contact with a profiled architectural item.

Preferably, the bar has an upturned distal end region terminating in the point formation, which preferably comprises a chisel edge disposed orthogonally to the longitudinal axis of the bar member, the chisel edge being in the same plane as the scribe element, the plane being parallel with and spaced apart from the bar member. The chisel edge can thus be used to follow the contours of a profiled substrate with the direction of the upturned end being the same as the direction of movement across the substrate, whereby the outer curved surface of the upturned end region does not foul the substrate and cause inaccuracies in the resulting scribe mark on the workpiece.

In a particularly preferred embodiment, scribing apparatus according to the invention has a roller member at one end of the bar member and a point formation with an upturned chisel edge formed at the other end of the bar member, the axis of rotation of the roller member, the scribe element and the chisel edge all being in the same plane, the plane being parallel - with and spaced apart from the bar member.

The scribe element mounted in the housing may be such as to leave a visible, for example, pencil or ink trace on the workpiece, or may be intended to leave a fine groove in the workpiece. Preferably, the scribe element is double-ended, that is, it is adapted to leave a trace from contact of either end with the workpiece, whereby the apparatus may be inverted during use about its longitudinal axis, as described in more detail hereinafter, leaving a continuous trace on the workpiece.

In use and because of the coplanarity of the roller member axis, the scribe element and the chisel edge, the user of the apparatus desiring for example to reproduce, on a workpiece panel, the profile of a wall surface skirting board, in order to cut the panel to fit the wall and skirting board, can hold the apparatus with the bar extending generally away from the wall at a right angle and mark a line on the workpiece while the roller member is in contact with and moving down the wall and subsequently while the point formation is in contact with and moving down the skirting board, it being necessary only to turn the apparatus over about a lateral axis when the apparatus reaches the transition between the wall and skirting board, in order to achieve continuity of the marked line with substantially no offset or parallax error. If necessary, the disposition of the housing along the bar can be adjusted so that, following inversion about the lateral axis, the working end of the scribe element is the same distance away from the wall. Alternatively, the housing can be pre-set along the bar so that the working end of the scribe element is midway or equidistant between the point formation and the remote or distal wall-contacting part of the surface of the roller member.

Conveniently, the roller member comprises a central, fixed boss with a wheel element mounted thereon for rotation. The boss may comprise a protrusion terminating in an axial point, whereby the apparatus may alternatively be used to mark an arc or a circle on a workpiece in a similar manner to a pair of compasses. The bar member may carry indicia to show units of length and the housing may incorporate a window or other means to enable the housing to be set with the scribe element at a pre-determined distance from one or other of the bar ends, or otherwise accurately to determine the distance between one or other of the bar ends and the scribe element.

The apparatus according to the invention may additionally include a slidable block removably mountable on the bar element for holding against the straight or curved edge of an item and to scribe thereon a follower line, as in the manner of a marking gauge.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings of which:

Figure 1 is a perspective view from one side of scribing apparatus;

Figure 2 is a perspective view from the other side of the apparatus of Figure 1 and also showing an optional block for mounting on the bar; and Figure 3 is a plan view of the apparatus of Figures 1 and 2.

In Figure 1 of the drawings, the apparatus shown generally at 10 consists essentially of an elongate rectangular bar 11 with an upstanding formation 12 at one end housing an axle for a pair of wheels 13 and an upturning 14 at the other end terminating in a flat face defining, with the curved upturning, a chisel-edge 15. Mounted for longitudinal sliding movement on the bar 11 is a housing 16 through which is laterally mounted a scribing or marking lead

17 having a marking point extending from each side of the housing, as more clearly seen with reference to Figure 3. The lead 17 is joumalled within the housing 16 by a split collet

18 held in place in a channel in the housing by a grub screw 19 (Figure 2). A manually-operable screw 20, the remote end of which bears on the collet, can be released to allow the length of lead protruding from the collet to be adjusted and also to allow the housing to be slid along the bar, since the channel which carries the collet in the housing is open at the side remote from the screw 20, whereby the distal surface of the collet bears directly against the upper surface of the bar. When the desired length of lead protrudes from the collet, and/or when the housing is at a desired location on the bar, the screw 20 is tightened to exert a lead-gripping force across the halves of the collet and to cause the collet to engage the bar with sufficient force to resist further sliding movement.

The central bush for the wheels 13 is formed as a cone 21 the pointed end 22 of which can be used as a fulcrum for describing an arc or circle on a workpiece with the lead 17.

The axis of the bush, the central longitudinal axis of the lead 17 including the tips thereof and the chisel edge 15 at the other end of the bar 11 are co-planar, the plane being parallel with and spaced apart from the plane of the bar 11.

The bar 11 may carry linear measurement indicia, as shown in Figures 1 and 3. Conveniently, the bar 11 is formed from stainless steel, the housing 16 from brass and the wheels 13 from nylon, but other materials may be used. With reference to Figure 2, a nylon block 23 is formed with a central slot 24 for push-fitting over the bar 11 at any desired location. The block has a flat face 25 at one side, provided with a rabbet 26, and a pair of raised ridge formations 27 equidistant from the slot at the other side. The block may be fitted to the bar either with the face 25 or with the ridge formations 27 towards the housing 16. The apparatus can then be used as a marking gauge, either with the flat face 25 abutting the edge of a flat linear substrate or with the ridge formations 27 abutting the edge of a curved substrate, the equal disposition of the ridges on either side of the slot ensuring that the lead 17 is normal to a notional tangent to the curved substrate surface at the point where it is intersected by the bar 11.

With reference to Figure 3, the lower wall of the housing 16 is formed with an aperture 28 to enable the measurement indicia to be viewed in alignment with the lead 17.

In use and with the edge 15 being employed to follow the peaks and valleys of, say, a skirting board or dado rail, the apparatus will be moved with the flat face defining the edge 15 facing in the direction of movement over an advancing or outer-projecting curve of the profile and away from the direction of movement over a regressive or inner-projecting curve, to avoid contact between the outer face of the upturning 14 and the skirting board or dado rail, such contact resulting in inaccuracies in the trace formed on the workpiece. The apparatus must therefore be inverted about its longitudinal axis each time it traverses the transition between outer- and inner-projecting curves, the respective ends of the double-ended lead 17 resulting in a continuous trace on the workpiece each time the apparatus is inverted.

Claims

1. Scribing apparatus comprising a bar member on which is slidably mounted a housing for a scribe element, the bar having at one end a roller member for contact with a wall.

2. Apparatus according, to claim 1, in which the roller member comprises a wheel mounted about an axis of rotation orthogonal to the longitudinal axis of the bar member and in the same plane as the scribe element, the plane being parallel with and spaced apart from the bar member.

3. . Scribing apparatus comprising a bar member on which is slidably mounted a housing for a scribe element, the bar having at one end a follower member for contact with a wall and at the other end a point formation for contact with a profiled architectural item.

4. Apparatus according to claim 3, in which bar has an upturned distal end region terminating in the point formation, the point formation comprising a chisel edge disposed orthogonally to the longitudinal axis of the bar member, the chisel edge being in the same plane as the scribe element, the plane being parallel with and spaced apart from the bar member.

5. Apparatus according to any preceding claim, the apparatus having a roller member at one end of the bar member and a point formation with an upturned chisel edge formed at the other end of the bar member, the axis of rotation of the roller member, the scribe element and the chisel edge all being in the same plane, the plane being parallel with and spaced apart from the bar member.

6. Apparatus according to any preceding claim, in which the scribe element is double-ended.

7. Apparatus according to any preceding claim, in which the roller member comprises a central, fixed boss with a wheel element mounted thereon for rotation, the boss comprising a protrusion terminating in an axial point.

8. Apparatus according to any preceding claim, in which the bar member carries indicia to show units of length and the housing incorporates means to enable the indicia to be viewed in alignment with the scribe element.

9. Apparatus according to any preceding claim, further including a slidable block removably mountable on the bar element for holding against the straight or curved edge of an item and to scribe thereon a follower line.