GB2217476A - Graphics apparatus for producing outlines - Google Patents

Abstract

Apparatus for producing outlines for use in graphics by producing an outline of artwork on a light-sensitive sheet, comprising a first support plate formed by the top of a box, and which supports a light-sensitive sheet and a first image e.g. positive, of the artwork to be outlined. A second transparent plate (3) is hinged at (4) so that it may be lifted, and a negative can be adhered to the underside of the plate in a required position and comprising a second image of the artwork to be outlined. The first and second plates are superimposed and rotation of handle 23 which is connected to eccentric shaft 12 causes the movement to be transmitted to plate (3) and thus produce relative rotational motion between the plates so that when the transparent plate (3) is illuminated whilst the plates are in continuous relative movement, light falls on the light sensitive sheet carried by the first support plate (2) to produced the required outline. <IMAGE>

Description

GRAPHICS APPARATUS This invention relates to an improved apparatus for producing outlines for se in graphics.

A frequent problem arising in graphics is the accurate production of outlines. A method has been evolved which has proved beneficial in this area. Positive and negative images are produced of the work of which an outline is required. The positive is placed over a light sensitive film and the negative is translated with respect to the positive to produce a circular motion. Whilst the movement of the negative with respect to the positive is proceeding light is shone onto the light sensitive film. This produces an accurate outline around the shape required.

The thickness of the outline produced depends on the radius of the circle which the negative describes. Several types of apparatus have been proposed which use this system such as those described in US Patent No 3204544 and US Patent No 286883. It is therefore an aim of the invention to produce apparatus for producing outlines which is compact and preferably portable.

According to the present invention there is provided apparatus for producing an outline of artwork on a light sensitive sheet comprising a first support plate for supporting a light-sensitive sheet and a first image of the artwork to be outlined, a second transparent plate for accommodating a second image of the artwork to be outlined, the first and second plates being superimposed on and substantially parallel to each other and arranged for relative slidable motion in a predetermined path in such a way that when the transparent plate is illuminated whilst the plates are in continuous relative movement, light falls on the light-sensitive sheet to produce the required outline.

Preferably the first image is a positive image for placing on top of the light sensitive sheet on the support plate and the second image is a negative image for securing to the underside of the transparent plate.

Preferably the apparatus also includes means for manually or automatically imparting rotational movement to the transparent plate, comprising a main shaft having an eccentric bore, the eccentric bore accommodating a post which is indirectly connected to the transparent plate, such that rotation of the main shaft causes the post and hence the transparent plate to describe a circle, the radius of the circle described being determined by the position of the post within the eccentric bore of the main shaft. Preferably the post is also coupled to a rotatable dial which allows the position of the post within the eccentric bore to be adjusted manually and also gives a visual indication of the position of said post.

Preferably there is provided means for ensuring universal circular movement of the whole of the transparent plate with respect to the support plate, said means comprising a first elongate member having fixed to it at one end the post and fixed at at least two horizontally spaced-apart points along its length to the transparent plate, and two elongate pivoting members opposite said first elongate member, the two pivoting members being pivotable about their respective centres and engaging together at their ends, a first connecting rod joining one end of the first elongate member and one end of one of the pivoting members, and a second connecting rod joining the other end of the first elongate member and one end of the other pivoting member such that circular motion imparted to one end of the first elongate member by the rotation of the post is transmitted through the connecting rods and the pivoting members to the opposite end of the elongate member thus ensuring universal circular movement of the whole of the transparent plate.

Preferably the distance between the first elongate member and the pivoting members is adjustable.

Preferably the apparatus also includes means to adjust the position of the centre of rotation of the transparent plate by including means to slide the transparent plate on the support plate to centre the negative on top of the positive before starting the circular motion of thetransparent plate with respect to the support plate.

Preferably the apparatus includes readily detachable means for transforming the rotational movement of the main shaft into a reciprocating movement of the transparent plate in a fixed straight line at a predetermined angle, whilst the transparent plate is illuminated, thus forming a shadow around a previously produced outline.

Examples of apparatus in accordance with the present invention will now be described with reference to the accompanying drawings in which: Figure 1 is a perspective view of the top of an example of apparatus in accordance with the present invention; Figure 2 is a view of the internal mechanisms of the apparatus shown in Figure 1; Figure 3 is an exploded view of the variable eccentric mechanism of the apparatus shown in Figure 1; Figure 4 is a plan view of a mechanism for allowing the transparent plate to be slid over the support plate in a straight line at a fixed angle; Figure 5 is a longitudinal section through- the mechanism of Figure 4; and, Figure 6 is an example of a shadowed outline produced by apparatus in accordance with the present invention.

Figure 7 is a partially cut-away view of a preferred embodiment of the invention; Figure 8 is a view of the means for ensuring universal rotational movement of the transparent plate, as used in the apparatus of Figure 7.

The apparatus comprises a wooden box 1 the top of which 2 forms a support plate and a sheet of light sensitive paper is placed on top of the support plate and the positive is placed in the required position on top of the light sensitive sheet. A transparent plate 3, typically of perspex, is hinged at 4 so that it may be lifted and the negative can be adhered to the underside of the plate in a required position. The plate 3 includes two bores 5 through which a small bolt passes of much smaller diameter than bores 5. A screw top 6 screws into a base 7 connected to the box such that when top 6 is screwed tightly against 7 the plate 3 is held firmly in position.

However, when top 6 is loosened the bolt can move in the bore 5 to allow the negative to be positioned so that it is aligned correctly with the positive.

The perspex plate 3 is moved by moving the base 7 which is attached by screws 8 to an elongate member 9 lying within the box. The mechanism 10 at the corner of the box transmits rotation of a main handle 11 to a circular motion of eccentric shaft 12. The circular motion of shaft 12 is transmitted along elongate member 9 via connecting rods 13, 14 and two elongate members 15 and 16. The elongate members 15 and 16 are each pivoted at their centre points at pivots 18, 19 respectively, and also pivot with respect to each other at a roller 17 positioned between the ends of the members 15 and 16. Springs 20 and 21 urge the members 15, 16 and the elongate member 9 respectively into their correct positions, the springs 20, 21 each being attached at their opposite end to a fixed point on the box 1.

The component of movement of the eccentric shaft 12 along the axis of 9 is transmitted through elongate member 9 and the perpendicular component is transmitted through the connecting rods 13, 14 and pivoting members 15, 16. A guide member 22 serves to limit the movement of member 9.

This guide member allows a clearance of the sides of the box of approximately 4mm as the member 9 is moved. In order to allow adjustment of the position of elongate member 9 to be within this clearance, semi-spherical mounts 13a, 14a are positioned at the threaded ends of the connecting rods 13, 14 respectively and may be fixed in a desired position on the rods by locking nuts 13b, 14b.

The mechanism for conversion of the rotational movement of the shaft 12 to a circular translation of the transparent plate 3 is shown in more detail in Figure 3 and will now be described in more detail. Rotation of handle 23 causes rotation of shaft 24 which transmits rotation to eccentric shaft 12 via peg 25 in eccentric bore 26. The position of the peg 25 with respect to the eccentric shaft 26 effects the rotation of bore 26 through which a shaft aligned with peg 25 passes (not shown in drawing). The relative position of peg 25 in bore 26 is altered by rotating the shaft 24 when stop 27 has been loosened. A dial 28 provides a gauge for the radius of rotation imparted. When stopper 27 is tightened on the shaft 24 the peg 25 is fixed in position.

Thus the rotation of handle 23 causes the eccentric shaft connected to the elongate member 9 to move with a circular motion.

With reference to.Figures 4 and 5, an attachment for allowing the transparent plate 3 to be slid in a straight line at a fixed angle across the support plate 2 comprises a slide 30 mounted within a housing 31. The housing 31 is rotatably mounted on a scale 32 lying beneath the slide, and may be fixed at any desired angle to the plane defined by the edge of the box 1 by a locking knob 33. The slide 30 may be pushed along housing 31 by rotating a handle 34 connected to a threaded rod 35 fixed to the slide 30. The slide 30 has fixed on its upper surface two bars 36, 37.

Both of these bars have longitudinal slots 38a, 38b, 38c, 38d, extending along the longitudinal axis of the bar, at each end. The bar 36 is attached at one end to an aluminium strip 3a fixed to the support plate 3 by means of a mount 39 accommodated within the slot 38a. At the other end, the bar 36 is-attached to the slide 30 by means of a mount 40 accommodated within slot 38b. The second bar 37 is attached to the strip 3a by a mount 42 accommodated within the longitudinal slot 38c. At the opposite end, the bar 37 is attached to the slide 30 by means of a mount 41 accommodated within the longitudinal slot 38d.

In operation, rotation of the shaft 12 causes the mounted 39, 40, 41, 42 to move within their respective longitudinal slots 38a, 38b, 38c, 38d in such a way that the rotation of the handle 23 results in a reciprocating movement of the transparent plate 3 in a straight line at a fixed angle.

Thus if the transparent plate 3 is illuminated during this movement, a shadow will be produced around the outline, as shown in Figure 6.

In order to change the angle of the straight line, the locking knob 33 is released, the housing 31 including slide 30 is rotated into the required position as measured on the protractor scale 32, the locking knob 33 is tightened and the handle 23 (see Figure 3) is rotated as before.

The depth of the shadow produced can be altered by rotating handle 34 which causes the slide 30 to move within the housing 31, thus determining the amplitude of the reciprocating motion and therefore the depth of the shadow.

This attachment allows accurate production of shadowed outlines.

A preferred construction which operates on the same principles as the embodiment shown in Figures 2 and 3 is illustrated in Figures 7 and 8, in which corresponding parts are numbered as in Figures 2 and 3. In this construction, there are two springs 50, 51 both located at one side of the box. Spring 50 is connected between an end of bar 9 and a fixed point 52 on'the box, and spring 51 is connected between an end of bar 15 and a hook 53 screwed into the wall of the box.

The transparent plate 3 is fixed to the box 1 and to the bar 9 by means of two fittings 55, 56 each comprising an upstanding, externally threaded post 55a (56a) surrounded by a collar 55b which has a bore of greater size than the post. The transparent sheet 3 rests on top of collar 55b, the washer 55c is placed on top of the sheet, over post 55a, and head 55d which has an internally threaded downwardly depending flange is screwed down over post 55a to secure the sheet 3 to bar 9. By unscrewing head 55d, the sheet 3 can be moved slightly as required to align the two images, the movement being accommodated by the oversized bore in collar 55b.

Connecting rod 14 is fixed between bar 16 and bar 9, and the other connecting rod 14 is fixed at one end to bar 9 and has an adjustable lock nut 60 at its adjustable connection with bar 15, to enable the distance between bar 9 and bars 15 and 16 to be adjusted.

In this embodiment, the mechanism for producing the rotational motion of transparent sheet 3 is slightly different from that of Figures 2 and 3. The mechanism comprises a circular post 62 having an upper section 62a and a lower section 62b, the two sections being eccentrically mounted with respect to each other. The uppermost end of upper section 62a is threaded and includes a vertically running ridge 63 which locates within a correspondingly shaped slot in member 64. Post 62 passes through an eccentrically located bore 65 in shaft 66, the latter being caused to rotate, in operation, with respect to housing 67. A handle 23 on a mounting 11 (as in Figure 3) sits over member 66, member 64 sits on top of mounting 11, and head 68 is screwed down over the protruding end of post 62 to hold all of the components together. Rotation of handle 23 causes member 66 to rotate which in turn causes post 62 to rotate. This imparts the desired rotation to one end of bar 9, and this is transmitted via connecting rod 14, pivoting bar 16, pivoting bar-15 and connecting rod 13 to the other end of bar 9, thus ensuring universal rotational movement of the whole of the transparent plate 3.

The radius of rotational movement is adjusted by rotating member 64 (and hence post 62a) to change the eccentric position of post 62 within eccentric bore 65.

Claims (8)

1. Apparatus for producing-an outline of artwork on a light sensitive sheet, said apparatus comprisin a first support plate for supporting a light-sensitive sheet and a first image of the artwork to be outlined, and a second transparent plate for accommodating a second image of the artwork to be outlined. the first and second plates being superimposed on and substantially parallel to each other and arranged for relative slidable motion in a predetermined path in such a way that when the transparent plate is illuminated whilst the plates are in continuous relative movement, light falls on the light-sensitive sheet to produce the required outline.

2. Apparatus according to Claim 1. including means for manually or automatically imparting rotational movement to the transparent plate, said means comprising a main shaft having an eccentric bore, the eccentric bore accommodating a post which is indirectly connected to the transparent plate, such that rotation of the main shaft causes the post and hence the transparent plate to describe a circle, and the radius of the circle described being determined by the position of the post within the eccentric bore of the main shaft.

3. Apparatus according to Claim 2, in which the post is also coupled to a rotatable dial which allows the position of the post within the eccentric bore to be adjusted manually and also gives a visual indication of the position of said post.

4. Apparatus according to Claim 2 or 3, including means for ensuring universal circular movement of the whole of the transparent plate with respect to the support plate.

said means comprising a first elongate member having fixed to it at one end the post and fixed at at least two horizontally spaced apart points along its length to the transparent plate. and two elongate pivoting members opposite said first elongate member. the two pivoting members being pivotable about their respective centres and engaging together at their ends. a first connecting rod joining one end of the first elongate member and one end of one of the pivoting members. and a second connecting rod joining the other end of the first elongate member and one end of the other pivoting member such that circular motion imparted to one end of the first elongate member by the rotation of the post is transmitted through the connecting rods and the pivoting members tp the opposite end of the elongate member, thus ensuring universal circular movement of the whole of the transparent plate.

5. Apparatus according to Claim 4, in which the distance between the first elongate member and the pivoting members is adjustable.

6. Apparatus according to any one of the preceding claims, including means for adjusting the position of the centre of rotation of the transparent plate by including means to slide the transparent plate on the support plate to centre the negative on top of the positive before starting the circular motion of the transparent plate with respect to the support plate.

7. Apparatus according to Claim 2, including readily detachable means for transforming the rotational movement of the main shaft into a reciprocating movement of the transparent plate in a fixed straight line at a predetermined angle. whilst the transparent plate is illuminated thus forming a shaddow around a previously produced outline.

8. Apparatus according to Claim 1 and substantially as hereinbefore described with reference to, and as shown in the accompanying drawings.