NZ224967A - Two-directional parallel rule; two pairs of wheels at right-angles selectively operable by tilting rule - Google Patents

Description

224967 NEW ZEALAND PATENTS ACT 19 53 No.: 224967 Date: 9 June 1988 COMPLETE SPECIFICATION "Improvements in or Relating to Multi Directional Parallel Rule For Navigation and Draughting WE ALBERT MAURICE PROWSE, a New Zealand Citizen, of 28 Sorrel Crescent, Bucklands Beach, Auckland, New Zealand and GARY CRAIG PROWSE, a New Zealand Citizen, of 26 Parramatta Place, Howick, Auckland, New Zealand hereby declare the invention for which /U<2> pray that a patent may be granted to/w©', and the method by which it is to be performed, to be particularly described in and by the following statement: ■ ■ :T7"n ; 2 4 AUG 1989 ~—an-i fSij 2248C This invention relates to a rule particularly a multi-directional type parallel rule.

The two types of parallel rules presently in common use are the stepping type and the one way roller type.

In particular for navigational plotting stepping type parallel rules are not always satisfactory as they require both hands to operate. The movement of a boat can be such that it is often desirable to hold oneself steady with one hand while plotting a course or drawing a position.

Present types of roller parallel rules move in one direction only, namely forward and backwards, therefore the area covered is limited to the length of the rule unless it is lifted off the paper and reset for another area.

Neither stepping type or one way roller type parallel rules can perform all the functions normally required in line drawing or chart plotting without the use of other instruments such as set squares, protractors and dividers and in the case of chart plotting, mathematical calculations to allow for compass variation and magnetic deviation.

As such existing parallel rules are disadvantageous.

It is therefore an object of the present invention to provide a rule which will obviate or minimise the foregoing disadvantages in a simple yet effective manner or which will at least provide the public with a useful choice. *24967 ;Accordingly the invention consists in a rule comprising a plate having an upper surface and a lower surface defining a ruling edge between said surfaces, said ruling edge being a straight edge or having a predetermined shape; ;a first pair of spaced-apart wheels supported by said plate so as to be rotatable relative to said plate, said first pair of wheels protruding from the lower surface of said plate for enabling said plate to be rolled along a surface in a first direction; ;a second pair of spaced-apart wheels supported by said plate so as to be rotatable relative to said plate, said second pair of wheels protruding from the lower surface of said plate for enabling said plate to be rolled along a surface in a second direction substantially perpendicular to said first direction; and a housing including spaced-apart front and rear walls extending from the upper surface of said plate, said first and said second pairs of wheels being located between said front and said rear walls. ;This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth. ;The invention consists in the foregoing and also envisages constructions of which the following gives examples. ;One preferred form of the invention will now be described with reference to the accompanying drawings in which: ;Figure 1 is a plan view of a rule according to one preferred form of the invention; ;and ;Figure 2 is an end view of the rule of Figure 1. ;?2 4967 ;Referring to the drawings a rule 1 is provided which in the preferred form has a plate 2 which provides a desirably shaped edge and in particular straight edge 3. Two pairs of spaced apart wheels are mounted in the plate and in the preferred construction a housing 4 is provided with a pair of dividing walls 5 spaced inwardly from the end walls 7 of the housing. Between the dividing walls 5 is provided a pair of spaced apart first wheels or rollers 6 which may be mounted on an axle 8 the ends 9 of which may be engaged with apertures in the walls 5. A keyhole type aperture extending from the bottom edge of the wall 5 may be provided into which the axle ends 8 may be snapped. In the preferred construction the wheels or rollers 6 have some width for example about lcm and are provided with a knurled finish preferably being formed of metal such as copper or brass. ;A pair of second wheels 10 is provided and the wheels again may be about lcm in width with a knurled finish being formed in metal and these are provided so that their axes of rotation are substantially at right angles to the axis of rotation of the wheels 6. The wheels 10 may be provided on axles 11 which may snap into keyhole apertures in the front wall 12 and rear wall 13 of the housing 4. ;The wheels 6 are set so that the bottom parts 15 of the wheels extend below the plate ;2 thus the plate 2 can rock a little on the axle of the wheels 6. The wheels 10 are ;Aojts positioned so that with the straight edge 3 resting on the surface 16 the lowers-part 15 of the wheels 6 are in contact with the surface 16 but the wheels 10 are free of that surface. ;However the positions of the axles 11 in the rear wall 13 are desirably higher in use than /nAtS ;the positions of the fade-11 in the front wall 12. ;Thus the lower surfaces 17 of the wheels 10 are at an angle to the plate 2 as can be ;Bseen in Figure 2. Thus in use if the wheels are rocked about the wheels 6 until the L0 comes into contact with the surface 16 a further continuation of that motion will cause the lower parts 17 of the wheels 10 to come into contact with the surface ;924967 ;allowing the lower parts 15 of the wheels 6 to be lifted from that surface as can be seen in Figure 2. ;The included angle between the plane of the plate 2 and the plane of the lower surface of the wheels 10 is desirably quite small and about 5 degrees has been found suitable. ;In that position the rule can be moved in the direction of arrow 18 shown in Figure 1. When rocked onto the wheels 6 movement of the rule in a direction at right angles to the arrow 18 is possible. ;The plate 2 can be marked with any suitable markings for example for navigational purposes, draughting purposes or otherwise. ;In the preferred form of the invention a pivoting arm 20 is provided and this can be attached to a flexible dome 21 for example moulded into plate 2 desirably formed of a plastics material. Thus the arm 20 has an aperture 22 at one end thereof that may be snapped onto the dome as the diameter at the base of the dome is smaller than the diameter at the top as can be seen from Figure 2. The walls of the aperture 22 may be similarly sloped. The dome 21 is made in several segments so that each segment can flex and cause the top of the segment to bend inwards therefore reducing the diameter of the segmented circle when the arm 20 is pulled off the dome 21 to be placed on a further dome 23 at the other end of the construction. The fit between the domes 21 and 23 and the arm aperture is sufficiently tight so that friction will keep the arm 22 at whatever angle it is set to during use. ;For measuring distances between two positions for navigation purposes the arm 20 and the rule edge 3 are marked with small arrow heads 24 and 25 and the arm 20 can be adjusted so that the arrow heads 24 and 25 span the distance to be measured. The distance is then matched against the latitude scale on the chart to obtain nautical miles thereby eliminating the need for separate dividers. The pivoting arm 20 can be placed on either dome 21 or 23 to suit west or east variation and the degree set at the sum of compass variation and magnetic deviation to obtain true course, along the rule edge 3 ;5 ;A ;q t* 1 C ^ /' ?24967 and compass course along the pivoting arm edge 26 which eliminates or reduces the need for further mathematical calculations.

The use of the invention is as follows.

In use the rule can be moved in a direction substantially at right angles to the direction of the edge 3 by pivoting the construction so that the bottom parts 15 of the wheels 6 engage the surface 16.

Movement in the direction parallel to the edge 3 can be achieved by rocking the construction back to the position shown in Figure 2 so that bottoms of the wheels 10 engage the surface 16.

Thus it can be seen that at least in the preferred form of the invention a rule is provided which has the advantage that movement in two directions can be achieved with a single hand and without the need to lift the rule from the supporting surface. This is desirable both for draughting and navigational plotting purposes and is particularly useful for navigational plotting purposes where the free hand can be used to hold a person steady whilst moving the rule.

£ X- >24907

Claims (8)

WHAT WE CLAIM IS:

1. A rule comprising a plate having an upper surface and a lower surface defining a ruling edge between said surfaces, said ruling edge being a straight edge or having a predetermined shape; a first pair of spaced-apart wheels supported by said plate so as to be rotatable relative to said plate, said first pair of wheels protruding from the lower surface of said plate for enabling said plate to be rolled along a surface in a first direction; a second pair of spaced-apart wheels supported by said plate so as to be rotatable relative to said plate, said second pair of wheels protruding from the lower surface of said plate for enabling said plate to be rolled along a surface in a second direction substantially perpendicular to said first direction; and a housing including spaced-apart front and rear walls extending from the upper surface of said plate, said first and said second pairs of wheels being located between said front and said rear walls.

2. A rule as claimed in Claim 1 wherein each of said wheels has a knurled peripheral surface.

3. A rule as claimed in either Claim 1 or Claim 2 wherein said second pair of wheels has an axis of rotation intersecting said plate with a relatively small included angle being defined therebetween.

4. A rule as claimed in Claim 3 wherein said included angle is about 5 degrees.

5. A rule as claimed in any one of the preceding claims further comprising a pivoting arm, and attaching means for attaching said arm to said plate so as to be pivotable relative to said plate and so as to be removable therefrom.

6. A rule as claimed in Claim 5 wherein said attaching means includes flexible domes moulded to said plate at ends thereof, respectively, each of said domes including a plurality of protrusions each having the cross section of a segment of a circle, and an ?24967 aperture defined in "Said arm enabling said arm to be engaged with a selected one of said domes. * s

7. A rule as claimed in Claim 6 wherein arrow markings are provided at said ruling edge and at an edge of saidipweterarm. ~\ V1

8. A rule substantially as herein described with reference to the accompanying drawings. .. N i DATED THIS SVK DAY OF V)ec." , by 1 t"t\ A.J. PARK & SON PER AGENTS FOR THE APPLICANT