This invention relates to a marking jig and relates particularly to a jig for marking a workpiece at desired angular locations and desired orientations.

It is often desired to mark a work piece with markings at predetermined angular positions. The markings may be desired for subsequent work to be performed on the work piece or for the application of indicia or the like at those locations.

In one particular field, in the manufacture of faces for clocks, it is necessary to locate the exact position of the clock numerals. While it is relatively easy to mark angular positions using a protractor or the like, this method is relatively time . consuming and inefficient.

Marking templates have been proposed in which the number locations are predetermined. Such templates, however, are only useful for one particular type or size of clock face. A large number of different templates is therefore required for different types and sizes of clock faces. It is therefore desirable to provide a marking jig which facilitates the setting of a number of predetermined angular positions on a work face.

It is also desirable to provide a marking jig particularly for marking the number positions for clock faces in which the position of the numbers is accurately determined irrespective of the shape of the clock face. It is also desirable to provide a marking jig in which the angular relationship of the points to be marked can be related to the angular position of those points around a centre.

It is also desirable to provide a clock face marking jig which is of simple construction and is quick and easy to use and which can be used for any type of clock face marking.

According to one aspect of the invention there is provided a marking jig comprising a base adapted to be engaged with a work piece to be marked, an arm adapted to engage with the base and be angularly movable relative thereto, locating means to locate the arm at one or more desired angular positions relative to the base and a set piece carried by the arm and by which a point is able to be set at a desired location relative to the base.

In one particular form, the marking jig is designed for the marking of relative positions of clock face numbers. For this purpose, the arm is provided with twelve holes equally spaced about an axis from which the arm extends radially. The base carries one or more locating pegs adapted to engage one or more of the holes in the arm. With this arrangement, the arm can be positioned at twelve different locations relative to the base, each location being 30° angularly spaced from each other. In an alternative arrangement, the holes may be provided in the base and the locating pegs mounted on the arm.

The arm of this embodiment has a slot extending along its length and the set piece may comprise either a marking block assembly which is mounted on the arm to engage within the slot or a number set template mounted on the arm. In the case of the marking block assembly, a screw clamp is used to clamp the marking block assembly at the desired radial distance from the center axis, and the block is provided with one or more holes through which punch marks, pencil marks or other markings may be made to the workpiece on which* the base is located. Thus, a nail may be used as a punch to mark relatively soft materials such as wood while a pencil may be used to mark relatively hard materials such as metal, ceramic, stone, etc.

In the case of the number set template, this comprises a substantially semicircular member having graduations marked at 30° intervals. The template is mounted to the arm by an appropriate screw clamp and it is able to be rotated relative to the arm so that one or other of the graduations can be aligned along the length of the arm while the straight side part of the template may be used to position a number in the correct vertical or upright position.

In order that the invention is more readily understood, one embodiment thereof will now be described with reference to the accompanying drawings wherein:

Figure 1 is a plan view of a base member in accordance with one embodiment of the invention,

Figure 2 is a division arm in accordance with the invention, Figure 3a is a cross-sectional view of a number set template for use with the arm of the invention,

Figure 3b is a plan view of the number set of Figure 3a,

Figure 4a is a cross- sectional view of a marking block assembly for use with

the arm of the invention,

Figure 4b is a plan view of the marking block assembly of Figure 4a, Figure 5 is a view illustrating the matter in which the marking jig is used, and Figure 6 is a view similar to Figure 5 but showing the number set template in use.

Referring to the drawings there is illustrated a marking jig which comprises a base plate 12 which may be of circular configuration, as shown, or of any other configuration. The base plate 12 is provided, in this embodiment, with three upstanding locating pegs 14. The pegs are accurately positioned around the edge of the base plate 12 so that the division arm 16 can be accurately located relative to the base plate 12.

The base plate 12 is provided with a centrally located hole 17 by which it is fastened to a workpiece 18, as shown in Figure 5, by means of a bolt extending through a shaft-receiving hole in the workpiece and a nut 19. When the base plate 12 is fixed to the workpiece 18, the arm 16 is mounted thereon. The arm 16 includes a central boss portion 21 having a central aperture 22 of a size greater than the size of the nut 19. Twelve locating holes 23 are accurately located equally spaced around the boss portion 21 and equally distant from the aperture 22. The locating holes 23 are of a size to engage over the locating pegs 14 to thereby locate the division arm 16 on the base plate 12.

The arm portion 24 extends radially from the boss portion 21 and is provided with a slot 26. The edges of the arm portion 24 or the edges of the slot 26 are provided with graduated scales 25 in either metric or imperial units indicating the radial distance from the axis of the division arm 16. A marking block assembly 27, as shown in Figure 4, may be engaged with the arm portion 24 by screw 28, wing nut 29 and washer 30, which is of a diameter greater than the width of the slot 26, but not so great as to cover the graduated scales 25. The assembly 27 includes an upstanding part 31 which engages within the slot 26 to locate the guide holes 32 relative to the arm portion 24. The holes 32 may be used for marking the workpiece 18 with a punch, pencil or other marking instrument.

It would be seen that, in use, the boss portion 21 of the division arm 16 can

be moved relative to the base plate 12 and located in any one of twelve angular positions. The marking block assembly 27 and/or template 33 may be used to accurately locate and position the numbers around the workpiece 18. If using the assembly 27, punch marks or pencil marks, or the like 39 (Figure 5) can be made to show the location of the numbers. If the workpiece is other than circular, such as square, the numbers can still be accurately located at the appropriate angular position by simply moving the marking assembly to the appropriate position along the arm portion 24.

Alternatively, or following use of the marking block assembly, a number set template 33 may be mounted on the arm portion 24 as shown in Figure 6. The template 33 is of substantially semicircular configuration with a locating boss 34 and a hole 36 to receive a screw 28 with a fastening wing nut 29. The template 33 has seven radial markings or graduations on its upper surface angularly spaced at 30°. In use, the template 33 mounted on the arm portion 24, is rotated until the centre graduation 37 extends along the length of the arm portion 24 with the straight edge 38 of the template 33 facing towards the aperture 22, and at right angles to the slot 26. This allows clock numbers to be placed, or marked radially on the workpiece by positioning the top, in the case of numbers 9 to 3, against the straight side 38 and, in the case of numbers 4 to 8, by placing the bottom of the number against the straight side 38.

Alternatively, if it is desired to have all the numbers located vertically, this is achieved by use of the markings or graduations 37 on the template 33 and by appropriate alignment of the template 33 on the arm portion 24. Thus, in order to place the numbers 12, 3, 6 and 9, the straight side 38 of the template 33 is set at right angles to the arm, and facing the aperture 22. At the twelve o'clock position, the top of the numeral twelve is placed against the straight edge 38 of the template 33. At the six o'clock position, the bottom of the numeral six is placed against the straight edge 38, while at the three o'clock and nine o'clock positions, the right side and left side, respectively, of the numbers are placed against the straight edge 38. The intervening numbers are then placed with the appropriate 30° or 60° angular marking 37 aligned on the arm portion 24 so as to provide a vertical straight edge 38 when the arm is appropriately positioned to the respective number positions.

It will be appreciated that the numbers may be marked on the workpiece in any suitable fashion, or may be provided in any suitable material and secured to the work piece by any suitable means, such as adhesive or the like. Naturally, the work face may be of any shape, and the numbers may be positioned at any desired radial distance. The marking jig of the invention enables numbers to be positioned accurately relative to the clock face centre irrespective of the radial distance therefrom of the number. Thus, numbers can be positioned on oval, square, or irregular shaped work pieces.

In a typical construction, the division arm 16 is approximately 200mm long and the slot is 8mm wide. However, the division arm 16 may be made any length commensurate with intended use.

It will be appreciated that various modifications or alterations may be made to the marking jig described with reference to the drawings without departing from the scope or spirit of the invention. For instance, to enable the jig to be fastened to workpieces or clock faces with different sized shaft-receiving holes, the hole 17 in the baseplate 12 may be larger than the shaft-receiving hole and a washer or insert may be provided, which is receivable in the hole 17 in the base plate 12 having a central hole to receive the bolt of the bolt and nut 19 fastener. In cases where the shaft- receiving hole is larger than the central hole in the washer, preferably at least the lower surface of the washer is conical so as to sit into the shaft-receiving hole of the workpiece to enable the same bolt to be used.

In another modification, the semi-circular template 33 may have outwardly extending wings (not shown) to extend the straight edge of the template.

It will be appreciated that the features of the present invention may be used for a marking jig for any purpose requiring the marking of positions at desired angular spacing around a point on a workpiece.