GB2120393A

GB2120393A - Rail type universal parallel ruler device

Info

Publication number: GB2120393A
Application number: GB08318543A
Authority: GB
Inventors: Hiroshi Mutoh; Masami Hikawa; Yoshinori Watanabe; Kouichi Yamazaki
Original assignee: Mutoh Industries Ltd
Current assignee: Mutoh Industries Ltd
Priority date: 1978-12-23
Filing date: 1983-07-08
Publication date: 1983-11-30
Also published as: GB2120393B; IT1119990B; GB8318542D0; GB2121194A; GB2040480B; IT7969456A0; FR2444573B1; GB8318543D0; FR2444573A1; DE2951690A1; DE2951690C2; GB2040480A; GB2121194B

Abstract

A rail type universal parallel ruler device, comprising a drawing board, a horizontal rail (151) mounted on the drawing board, a horizontal cursor (157) mounted on the horizontal rail shiftably along the horizontal rail, a vertical rail (160) the upper portion of which is journalled on a shaft (166) by the horizontal cursor rotatably in a plane perpendicular to the surface of the drawing board, a vertical cursor shiftably mounted on the vertical rail, and a head connected to the vertical cursor, wherein a first magnetic member (154, 155) is disposed over substantially the entire length of the horizontal rail in the longitudinal direction, and a second magnetic member (162, 163) is disposed on the horizontal cursor in opposition to the first mentioned magnetic member, and the magnetic force working between the first and second magnetic members is caused to work on the journalled portion (166) of the vertical rail and the horizontal cursor in the upward perpendicular direction relative to the surface of the drawing board. <IMAGE>

Description

1 GB 2 120 393 A 1

SPECIFICATION Rail type universal parallel ruler device

The present invention relates to a rail type universal parallel ruler device.

In the conventional rail type universal parallel ruler devices, a horizontal cursor is mounted shiftably on a horizontal rail by means of a roller.

Also, a vertical cursor is mounted shiftably on a vertical rail by means of a roller. Accordingly, when the cursor is shifted along the rail, rolling friction occurs between the roller and the rail. The 75 shifting of the cursor on the rail becomes heavy due to the frictional force, and travel of the roller becomes noisy. As a result, the head is unable to be shifted with a light force quality on the drawing board in a desired direction. A rail type universal 80 parallel ruler device has been developed by the same applicant as for the present application in which, in order to eliminate the foregoing drawback, a magnet is disposed over the entire length of the rail, and a magnet is disposed at the 85 side of the cursor and the cursor energized in the floating direction by the magnetic force of both the magnets, and the contact friction of the roller and the rail is decreased by the energizing force.

However, since this device is constructed such that the roller travels on the rail while contacting it, the foregoing drawback. is not completely eliminated.

The present invention provides a rail type universal parallel ruler device, comprising a drawing board, a horizontal rail mounted on the drawing board, a horizontal cursor mounted on the horizontal rail shiftably along the horizontal rail, a vertical rail the upper portion of which is journalled on a shaft by the horizontal cursor rotatably in a plane perpendicular to the surface of the drawing board, a vertical cursor shiftably mounted on the vertical rail, and a head connected to the vertical cursor, wherein a first magnetic member is disposed over 105 substantially the entire length of the horizontal rail in the longitudinal direction, and a second magnetic member is disposed on the horizontal cursor in opposition to the first mentioned magnetic member, and the magnetic force working between the first and the second magnetic members is caused to work on the journalled portion of the vertical rail and the horizontal cursor in the upward perpendicular direction relative to the surface of the drawing board.

By means of the present invention the cursor of the rail type universal parallel ruler device may shift lightly and smoothly by utilizing the magnetic force of the magnetic members. 120 Moreover, the head may shift with a light force smoothly and quietly by causing the cursor to float relative to the rail for guiding the cursor by the magnetic force of the magnetic members.

Also the cursor may travel smoothly and quietly along the rail by controlling the position of the cursor perpendicular to the longitudinal direction of the rail for guiding the cursor by the repulsion magnetic force of the magnetic members.

Deflection of the horizontal rail may be prevented by applying no downward load by the dead weight of the vertical rail to the horizontal rail. An error is derived on the straightness of the horizontal rail when the horizontal rail is bent, and an error is derived in the precision of drawing.

The invention will be further described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a general view showing one embodiment of a rail type universal parallel ruler device; Figure 2 is a cross-section taken along the line B-B of Figure 3; Figure 3 is a plan view showing one embodiment of a vertical cursor; Figure 4 is a cross-section taken along the line A-A of Figure 3; Figure 5 is a cross-section showing an embodiment of a magnetic floating mechanism; Figure 6 is a plan view showing another embodiment of a vertical cursor; Figure 7 is a side view showing one embodiment of a mechanism for controlling the shifting direction of the cursor by the magnetic force; Figure 8 is a plan view of a horizontal cursor; Figure 9 is a cross-section showing another embodiment of a mechanism for controlling the shifting direction of the cursor by the magnetic force; Figures 10 to 13 are side views showing other embodiments of magnetic floating mechanisms; 100 Figure 14 is a side view showing one embodiment of a roller pressure relieving mechanism; Figure 15 is a side view showing another embodiment of a magnetic floating mechanism; Figure 16 is a side view showing another embodiment of a roller pressure relieving mechanism; Figures 17 to 19 are side views showing further embodiments of magnetic floating mechanisms; Figure 20 is a graph illustrating the characteristic curves of various magnets; Figure 21 is a general plan view showing another embodiment of a rail type universal parallel ruler device; Figure 22 is a side view showing another embodiment of a magnetic floating mechanism; Figure 23 is an exterior view of a vice type fixture,- Fig ures 24 to 26 are side views showing further embodiments of magnetic floating mechanisms; Figure 27 is a plan view of a drawing board; Figure 28 is a perspective view of a rail type universal parallel ruler device; Figure 29 is a perspective view of a part of the rail type universal parallel ruler device shown in Figure 28; and G13 2 120 393 A 2, Figures 30 to 33 are side views showing other embodiments of magnetic floating mechanisms.

Figures 1 to 4 show a drawing board 1 which is mounted on a reclining table so that it can be fixed at a given inclined angle. A horizontal rail 2 is fixed to the drawing board 1, and a horizontal cursor 4 is shiftably connected to the horizontal rail. A vertical rail 6 is mounted on the horizontal cursor 4, and a tail portion roller 8 is mounted rotatably on one end of the vertical rail. A vertical cursor 10 is shiftably connected to the vertical rail 6, and a head 12 is connected to the cursor 10 by a hinge member 11. Straight edges 63, 64 are mounted on the head 12.

In the longitudinal direction of the vertical rail 6, cursor traveling surfaces 70, 7 1, cursor upper direction control surfaces 72, 73, which are formed in parallel with the surface of the drawing board 1, and horizontal swing control surfaces 74, 75 are formed in perpendicular to the surface of 85 the drawing board 1. The surfaces of rollers 76, 77 pivotally supported rotatably on the vertical cursor 10 contact the horizontal swing control surface 74, and the surfaces of rollers 78, 79 contact the horizontal swing control surface 75.

Numerals 80, 81, 82, 83 are magnetic members of long plate type which are fixed along the surfaces 70, 72, 71, 73, and in this embodiment, manganese aluminum magnet is used for the magnetic members. Numerals 84, 85 and 86, 87 95 are magnetic members, namely, magnets fixed on a rising portion of the vertical cursor 10, and the magnets are opposed in a certain gap with the magnets 80, 81, 82, 83 as shown in the drawing.

The polarity of the magnets which are mutually 100 opposed is set similarly, and the vertical cursor 10 is completely floated relative to the cursor traveling surfaces 70, 71 of the vertical cursor 6 by the repulsion magnetic force of the mutually opposed magnets, and also the vertical cursor 10 105 retains a predetermined gap to the upper direction control surfaces 72, 73. Numerals 88, 89, 90 are auxiliary rollers mounted rotatably on the vertical cursor 10, and are opposed to the magnetic pole surfaces of the magnets 80, 81 and 82, 83. The opposed gap of the magnets 80, 81, 82, 83 and rollers 88, 89, 90 is set smaller than the opposed gap of the magnets 80, 81, 82, 83 and 84, 85, 86, 87. On the magnets 80, 81, 82, 83, Teflon 91 is coated. By the way, it is 1 possible to apply a coating of the Teflon 92 on the surfaces of the magnets 84, 85, 86, 87 instead of providing the auxiliary rollers 88, 89, 90. The auxiliary rollers 88, 89, 90 and Teflon 91, 92 constitute the frictional force decreasing member. 120 In the foregoing construction, when the external stress along the vertical rail 6 is applied to the vertical cursor 10, 10, the vertical cursor 10 is shifted in the complete floating condition relative to the traveling surfaces 70, 71 of the vertical rail 6. When the strong external force is applied to the vertical cursor 10 and vertical vibration occurs, the auxiliary rollers 88, 89, 90 contact the magnets 80, 81, 82, 83, and the rollers 88, 89, 90 receive the pressure of vibration130 by the contact. When the vertical cursor 10 is shifted, the rollers 76, 77, 78, 79 are rotated while contacting the control surfaces 74, 75. The foregoing construction is provided between the horizontal cursor 4 and the horizontal rail 2.

In Figs. 5 and 6, numeral 95 is a roller pivotally supported rotatably on a rising portion 97 of a vertical cursor 96, and the roller 95 is mounted on a traveling surface 99 of a vertical rail 98.

Numerals 100, 101 are magnets fixed to the vertical cursor 96, and numerals 102, 103 are magnets fixed to the side of the vertical rail 98, and a left member side of the vertical cursor 96 on the drawing is floated relative to a traveling surface 104 of the vertical rail 98 by the repulsion magnetic force of the magnets 100, 102. In this embodiment, if at least a part of the cursor 96 is arranged to float relative to the traveling surface of the rail 98, the cursor 96 can be smoothly shifted along the rail 98, and as a result, it shows that satisfactory effect can be obtained. By the way, an embodiment in which the cursor 96 is floated relative to the traveling surface of the rail 98 by the attractive force of the go magnets is possible.

Next, another embodiment is described by referring to Figs. 7 through 9.

in this embodiment, a position in a right angle direction of the cursor to a longitudinal direction of the rail is controlled by the repulsion magnetic force of the magnets, and by this arrangement, the cursor can be shifted smoothly along the rail.

Numeral 112 is a horizontal rail fixed to an upper edge portion of a drawing board 111, and roller mounting surfaces 113, 114 are formed horizontally to the surface of the drawing board 111 in longitudinal direction of the rail 112. Rol lers 116, 117, 118 pivotally and rotatably supported on a horizontal cursor 115 are mounted on the roller mounting surfaces 113, 114. Numerals 119, 120 are a pair of suspending members suspended in parallel along a longitudinal direction of the horizontal rail 112, and magnets 121, 122 of long plate type are fixed on the suspending members so that the magnetic pole surfaces are perpendicular to the surface of the drawing board 111. Numeral 11 5a is a rising portion formed on the horizontal cursor 115, and a pair of long magnets 123, 124 are fixed on the rising portion in close proximity and opposition to the magnets 121, 122. The magnets 121, 123, and 122, 124 are disposed so that their identical magnetic poles are opposed mutually. Numeral 125 is a bracket connected to an end of a vertical rail 126, and its lower end is pivotally supported on the rising portion of the horizontal cursor 115 which is rotatably centering around a shaft 127 in parallel with the rail 112. A tail portion roller 129 is rotatably mounted on the other end of the vertical rail 126. A pair of magnets 130, 131 are fixed so that the magnetic pole surfaces are perpendicular to the surface of the drawing board 111. Numerals 132, 133 are magnets fixed to a rising portion of a vertical cursor 134, and the magnets are opposed in proximity of the magnets 130, it 3 GB 2 120 393 A 3 131 in the condition where the magnetic forces are repulsed. Numerals 135, 136, 137, 138 are magnets fixed in a longitudinal direction of the vertical cursor 16. Numerals 139, 140, 141, 142 are magnets fixed to a vertical cursor 134, and the magnets are opposed in such a condition where magnetic forces of the magnets 135, 139 and 136, 140 and 137, 141 and 138, 142 are repulsed, and the vertical cursor 134 is completely floated relative to the vertical rail 126 by the magnets 135, 136, 137, 138, 139, 140, 141 and 142. A head is connected to the vertical cursor 134 by means of a hinge member 144, and a straight edge is mounted on the head. By the way, in this embodiment, commercially available manganese aluminum magnets are used for such magnets. Next, an operation of the embodiment is described. 20 In Fig. 7, the magnets 121, 123 and 122, 124 85 are mutually strongly repulsed, and a position of right angle direction of the horizontal cursor 115 is controlled in its longitudinal direction to the horizontal rail 112. When the external stress is applied in a direction along its longitudinal direction of the horizontal rail 112 relative to the horizontal cursor 115, the horizontal cursor 115 is shifted in a condition that its vertical direction is controlled by the roller mounting surfaces 113, 114 and control surfaces f 13, 114 along the longitudinal direction of the horizontal rail 112, and the horizontal direction is controlled by the magnetic pole surfaces of the magnets 121, 122.

In Fig. 9, when the external stress is applied in the longitudinal direction of the vertical rail 126 to the vertical cursor 134, a vertical direction of the vertical cursor 134 is controlled by the magnetic pole surfaces of the magnets, and is rotatably supported on the horizontal cursor 157, and are in contact with the other rail surface of the perpendicular rail portion 156. Numerals 162, 163 are magnets fixed to the horizontal cursor 157 opposed to immediately below the magnets 154, 155, and the same pole surfaces of the magnets 154, 162 are mutually opposed, and repulsion force is caused to work between the magnets, and the different pole surfaces of the magnets 155, 163 are mutually opposed and the attracting magnetic force is caused to work between the magnets. Numeral 164 is a vertical rail, and a bracket 165 is fixed to one end of the vertical rail, and the lower portion of the bracket 165 is rotatably and pivotally 166 supported centering around an axis parallel to the horizontal rail 151 on the rising portion of the horizontal cursor 157. A tail portion of the vertical rail 164 is floated relative to the surface of the drawing board by the repulsion magnetic force of the magnets.

Next, an operation of this embodiment is described.

When the load W caused by the dead weight of the vertical cursor 164 is applied downwardly on the connecting portion of the horizontal cursor 157 and the vertical rail 164, namely, the shaft 166, the pressure (L-I)W I is applied to the opposed portions of the magnets 154, 162 in a direction where the magnets are caused to approach. Where L is a distance between the magnet 162 and the shaft 166, and I is a distance between the magnet 162 and the shifted along its longitudinal straight line direction 100 magnet 163.

of the vertical rail 126. The pressure of Next, another embodiment is described by referring to Fig. 10.

Numeral 150 is a drawing board, and on its upper edge portion, a horizontal rail 151 is fixed by a vice type fixture. Horizontal rail portions 152, 153 are formed on the lower portion of both side portions of the horizontal rail 151 along the longitudinal direction, and on the lower surfaces of the horizontal rail portions 152, 153, magnets 154, 155 are fixed over an entire length in the longitudinal direction. In almost a center portion of the lower portion of the horizontal rail 151, a perpendicular rail portion 156 is formed along its longitudinal direction. Numeral 157 is a horizontal cursor, and a plurality of vertical safety rollers 158, 159 are rotatably supported on the horizontal cursor 157, and the safety rollers 158, 110 is applied in a direction where the magnets are 159 are opposed by providing a proper interval on the horizontal surfaces of the horizontal rail portions 152, 153. Numeral 160 is a plurality of horizontal guide rollers pivotally and rotatably (L-I)W I is offset by the repulsion magnetic force of the magnets 154, 162, and the magnet 162 is opposed to the magnet 154 at a predetermined gap.

To the opposed portion of the magnets 155, 163, the pressure of WL I opposed, but this pressure is offset by the attractive magnetic force of the magnets 155, 163, and the magnet 163 is opposed to the magnet 155 at a predetermined gap. Rotary supported on the horizontal cursor 157, and are in 115 moment working on the horizontal cursor 157 contact with one rail surface of the perpendicular by the attractive magnetic force of the magnets rail portion 156. Numeral 161 is one or a plurality 155, 163 and the repulsion magnetic force of the of horizontal guide rollers which are pivotally and magnets 154, 162 is offset, and the guide rollers 4 GB 2 120 393 A 4 160, 161 are received almost no pressure from the rail surface, and the safety rollers 158, 159 are completely floated relative to the rail surfaces 152,153.

In the foregoing construction, when the force is applied in a given direction parallel to the surface of the drawing board 150 by grasping the handle of the head by the hand, the horizontal cursor 157 is shifted lightly and smoothly along the horizontal rail 15 1, and the vertical cursor is shifted along the vertical rail 164, and the head can be shifted to a desired position on the drawing board 150. By the way, as shown in Fig. 11, V-shaped groove rails 169, 170 are formed on the horizontal rail 168, and a convex stripe on the surface of the rollers 17 1, 172 rotatably and pivotally supported on the horizontal cursor 157 may be fitted to the V shaped groove rails 169, 170.

Numerals 173, 174 are magnets disposed so 85 that the repulion magnetic forces are worked mutually, and numerals 175,176 are magnets disposed so that the repulsion magnetic forces are worked mutually.

Next, another embodiment is described by referring to Fig. 12. Numeral 180 is a drawing board, and is fixed to a drawing board support frame of a drawing bench so that the drawing board can be set at a given inclined angle between the horizontal condition and the perpendicular condition relative to the floor surface. Numeral 181 is a horizontal rail fixed to an upper edge portion of the drawing 180 by means of a vice type fixture (not shown), and horizontal rail surfaces 181 a, 181 b and perpendicular rail surfaces 181 c, 181 d are formed on the horizontal rail over an entire length in the longitudinal direction, and a magnet 182 is fixed on the upper surface of the horizontal rail 181. Numeral 183 is a horizontal cursor, and a 105 plurality of vertical rollers 184, one or a plurality of vertical rollers 185, a plurality of horizontal rollers 186, and one or a plurality of horizontal rollers 187 are rotatably supported on the horizontal cursor 183, and the vertical rollers 184, 110 are mounted on the horizontal rail surfaces 181 a, 181 b, and the horizontal rollers 186, 187 are in contact with the perpendicular rail surfaces 181 c, 181 d. Numeral 188 is a vertical rail, and an upper portion of a bracket 189 is pivotally (190) 115 and rotatably supported on one end portion of the vertical rail 188 which centers around an axis parallel with the horizontal rail 18 1, and a magnet 192 is fixed to a projecting member 191 formed on the bracket 189. The same pole surface of the 120 magnets 192, 182 are opposed, and one end portion of the vertical rail 188 is floated relative to the upper surface of the horizontal rail.1 81 by the repulsion magnetic force of the magnets 192, 182. The magnets 192, 182 constitute the magnetic floating mechanism. A hollow cylindrical portion 193 is formed on the bracket 189 in a direction perpendicular to the surface of the drawing board, and a shaft 194 projected on the horizontal cursor 183 is slidably fitted to the 130 hollow portion 193 by means of a slide ball bearing 195. The shaft 194, slide ball bearing 195 and hollow portion 193 constitute the roller pressure relieving mechanism. A magnet (not shown) is fixed to the tail portion of the vertical rail 188, and the magnet is opposed to a magnet (not shown) fixed to a lower edge portion of the drawing board 180. The same pole surface of the magnet at the tail portion of the vertical rail 188 and the magnet at the lower edge portion of the drawing board 180 are opposed, and the tail portion of the vertical rail 188 is floated relative to the lower edge portion of the drawing board 180 by the repulsion magnetic force.

Next, an operation of the embodiment is described.

When the head is applied with pressure in a given direction parallel to the surface of the drawing board 180, the horizontal cursor 183 is controlled by the perpendicular rail surfaces 181 c, 181 d, and is shifted along the horizontal rail 18 1, and the vertical cursor is shifted along the vertical rail 188, and the straightedge can be shifted to a given position on the drawing board 180. When the inclined angle of the drawing board 180 is changed, or the head is raised and the under surface of the head is retained at a position floated relative to the surface of the drawing board 180, the load in perpendicular direction to the surface of the drawing board 180 which is applied to the bracket 189 is changed. In correspondence to the change of the load, an opposed gap of the magnets 192, 182 is changed and the bracket 189 is displaced in perpendicular direction to the surface of the drawing board 180. When the bracket 189 is displaced in perpendicular direction to the surface of the drawing board 180, the bracket 189 is slid to the shaft 194, and the horizontal cursor 183 is not interlocked with displacement of the bracket 189 in perpendicular direction to the surface of the drawing board 180 by the sliding motion of the bracket 189. Accordingly, no eccentric load is applied to the guide rollers 186, 187 for prevention of horizontal swing which contact the perpendicular rail surfaces 181 c, 181 d.

Namely, the slide bearing 195 and the shaft 194 constitute the roller pressure relieving mechanism for preventing change of the pressure of the guide rollers to the guide rail surfaces by the displacement of the magnetic floating gap of the vertical rail 188 to the surface of the drawing board.

Next, another embodiment of the relieving mechanism is described by referring to Fig. 13.

Numeral 200 is a horizontal guide roller fitted rotatably on a plurality of shafts 201 projected on a horizontal cursor 212 by a gap in a radial direction, and the surface of the roller 200 is in contact with the perpendicular rail surface 202a of the horizontal rail 202. Numeral 203 is a horizontal guide roller fitted rotatably on one or a plurality of shafts 204 projected on the horizontal cursor 212 at a gap in a radial direction, and the GB 2 120 393 A 5 surface of the roller 203 is in contact with the perpendicular rail surface 202b formed on the horizontal rail 202. The horizontal swing of the horizontal cursdr 212 to the horizontal rail 202 is prevented by the rollers 202, 203. Numeral 205 is 70 a plurality of vertical guide rollers rotatably and pivotally supported on the horizontal cursor 212, and the surface of the roller 205 is in light contact with the horizontal rail surface 202c formed on the horizontal rail 202. Numeral 206 is a horizontal safety roller pivotally and rotatably supported on the horizontal cursor 212, and is opposed to the horizontal rail surface 202d at a predetermined gap. Numeral 207 is a bracket fixed to one end of the vertical rail, and the lower portion of the bracket is pivotally (208) and rotatably supported on the rising portion of the horizontal cursor 212 centering around an axis parallel to the surface of the drawing board.

Numerals 209, 210 are magnets disposed at the 85 side of the horizontal rail 202 and the bracket 207, and the bracket 207 is floated relative to the horizontal rail 202 at a predetermined gap by the repulsion magnetic force of the magnets 209, 210. Other constructions are same with the foregoing embodiment, the description is omitted.

When the opposed gap of the magnets 209, 210 is changed, and the bracket 207 is liftably displaced in perpendicular direction to the surface of the drawing board, the horizontal cursor 212 is 95 interlocked with the bracket 207, and is inclined with the guide roller 205 as a fulcrum. When the horizontal cursor 212 is inclined, the shafts 201, 204 are also inclined to the perpendicular rails 202a, 202b, but the guide rollers 200, 203 are 100 not interlocked with the inclination of the shafts 201, 204 on account of the gap present between the shafts 201, 20 ' 4 and the guide rollers 200, 203 and as a result, the guide rollers 200, 203 are in contact with the perpendicular rail surfaces 105 202a, 202b in parallel therewith. By this arrangement, the eccentric load is prevented from being applied to the guide rollers 200, 203.

Next, another embodiment is described by referring to Fig. 14.

Numeral 215 is a bracket, and a vertical rail is fixed to the upper portion of the bracket. Numeral 216 is a hinge member, and one part of the hinge member is pivotally (217) and rotatably supported on the bracket 215 centering around an axis in parallel to the surface of the drawing board, and the other part of the hinge member 216 is pivotally (219) and rotatably supported on a rising portion of a horizontal cursor 218 centering around an axis to the above axis. 120 In the foregoing construction, when the bracket 215 is liftably displaced, the hinge member 216 is rotated centering around the axes 217, 219, and the lifting displacement of the bracket 215 is not transmitted to the cursor 218. Consequently, no 125 eccentric load is applied to traverse vibration preventing guide rollers 220, 221 of the horizontal cursor 218.

Next, another embodiment is described by referring to Fig. 15.

Numerals 225, 226 are convex curved surface rails formed over an entire length of a horizontal rail 227 in its longitudinal direction, and concave curved surfaces 229a, 230a, of the horizontal guide rollers 229, 230 pivotally and rotatably supported on the horizontal cursor 228 are fitted rotatably to the convex curved surface rails. Numeral 213 is a bracket, and one end of a vertical rail 232 is fixed to the upper portion of the bracket 213, and the lower portion of the bracket 231 is rotatably and pivotally (232) supported on the rising portion of the horizontal cursor 228 in a plane perpendicular to the surface of the drawing board. Numeral 233 is a magnet fixed to the upper surface of the horizontal rail 227 over an entire length of the horizontal rail 227 in its longitudinal direction, and the magnet 233 is opposed to a magnet 234 fixed to a projecting member of the bracket 23 1, and the bracket 23 1 is energized in upper direction by the repulsion magnetic force working between the magnets 233 and 234, and is floated relative to the horizontal rail 227 at a predetermined gap.

In the foregoing construction, the opposed gap of the magnets 233, 234 is changed, when the bracket 231 is moved vertically in a direction perpendicular to the surface of the drawing board, the rising portion side of the horizontal cursor 228 is moved vertically by being interlocked with the bracket 23 1. When the rising portion side of the horizontal cursor 228 is moved vertically, the concave curved surfaces 229a, 230a of the guide roller 229 for prevention of horizontal swing are slid in circumferential direction along the convex curved surface rails 225, 226, and the contact fitted condition of the convex curved surface rails 225, 226 and the guide rollers 229, 230 is maintained without the eccentric load being applied to the guide rollers 229, 230. By the way, safety rollers may be provided on the horizontal cursor 228 in opposition to the horizontal rail surface of the horizontal rail 227.

Next, another embodiment is described by referring to Fig. 16.

Numeral 236 is a guide rail portion formed on the horizontal rail 237 over an entire length in its longitudinal direction, which is formed with a convex curved surface 236a, and a concave curved surface 236b. Numeral 238 is a horizontal cursor, and a vertical guide roller 239, vertical safety roller 240, and horizontal guide rollers 241, 242 for prevention of traverse vibration are rotatably and pivotally supported on the horizontalcursor' and the guide roller 239 is mounted rotatably on a horizontal rail surface 243, and the safety roller 240 is opposed to the horizontal rail surface 244 at a predetermined gap. A convex curved surface is formed on the surface of the guide roller 241, and the convex curved surface is in tight contact with the concave curved surface rail 236b. A concave curved surface is formed on the surface of the guide roller 242, and the concave curve surface is in tight contact with the convex curved surface rail 236a.

The curvature of the concave curved surface rail 6 GB 2 120 393 A 6 236a and the convex curved surface rail 236b is set to be identical with the curvature of a rotary locus in vertical direction centering around the guide roller 239 of the horizontal cursor 238, and when the horizontal cursor 238 is rotated in the vertical direction centering around the guide roller 239 the rollers 241, 242 are arranged to slide while maintaining the tight contact condition with the rail surfaces 236a, 236b along the rail surfaces. Numeral 246 is a bracket.

In the foregoing construction, when the bracket 246 is moved vertically, the horizontal cursor 238 is moved vertically centering around the guide roller 239, and the rollers 241, 242 are slid along the rail surfaces 236a, 236b.

Accordingly, there is no chance that the eccentric load is applied to the rollers 241, 242 by the vertical displacement of the horizontal cursor 238.

Next, another embodiment is described by 85 referring to Fig. 17.

Numeral 250 is a rail member formed over an entire length of a horizontal rail 251 in its longitudinal direction, and a magnet 252 is fixed over an entire length of the rail member 250 in its longitudinal direction. Numeral 253 is a magnet disposed in opposition to the magnet 252 at the lower surface of a horizontal cursor 254, and same pole surfaces of the magnets 252, 253 are mutually opposed and repulsion magnetic force is worked between the opposed surfaces, and the horizontal cursor 254 is energized by the repulsion magnetic force in a direction of floating i relative to the rail member 250, and a guide roller 255 is in contact with a horizontal rail surface 256 by almost zero pressure. Numerals 257, 258 are horizontal guide rollers for prevention of traverse vibration, and inner rings of the guide roller are rotatably fitted to shafts 259, 260 projected on the horizontal cursor 254 by a gap in 105 a radial direction. Numeral 261 is safety roller, and numeral 262 is a bracket, and one end of a vertical rail 263 is fixed to an upper portion of the bracket 262, and the lower portion is rotatably and pivotally (265) supported on a rising portion 110 of the horizontal cursor 254 in a plane perpendicular to the surface of a drawing board 264.

In the foregoing construction, when the load of the bracket 262 in downward direction perpendicular to the surface of the drawing board 264 is changed, an opposed gap of the magnets 252, 253 is changed, and the horizontal cursor 254 is inclined in a vertical direction with the guide roller 255 as a fulcrum. The shafts 259, 260 are inclined to the perpendicular rail surfaces 266, 267 by the inclination of the horizontal cursor 254, but the rollers 257, 258 maintain the parallel contact condition against the perpendicular rail surfaces 266, 267 by a gap between the rollers 257, 258 and the shafts 259, 260, and the eccentric load is prevented from being applied to the rollers 257, 258.

Moreover, as the magnets 252, 253 are disposed so that the magnets are positioned on an axis perpendicular to the surface of the drawing board 264 which passes a connecting portion 265 of the perpendicular rail 263 and the horizontal cursor 264, the load applied in downward direction to the horizontal cursor 254 by means of the shaft 265 by the dead load of the vertical rail 263 and the external stress applied on the vertical rail 263 is offset by the repulsion magnetic force derived from the magnets 252, 253, and there is worked no pressure between the vertical guide 255 and the horizontal rail surface 256, and the horizontal cursor 254 is shifted along the horizontal rail 251 in almost a floated condition.

In the rail type universal parallel ruler device, when the load applied on the traveling member is changed, and a magnetic floating gap of the traveling member to the guiding member is greatly changed, various inconveniences are derived. Under the circumstances, in the following embodiment, the foregoing inconveniences are eliminated by arranging a plurality of magnetic pole tracks in parallel on the opposed portion of the traveling member and the guiding member. The foregoing arrangement is made by the following reason.

As shown in Fig. 20, when repulsion magnetic force of the magnet is set on the axis of coordinates and the gap of the magnets 270, 271 is set on the axis of abscissa, and magnets 270 are arranged in 8 rows in parallel so that mutually different poles are adjacent, and the magnets 271 are arranged in 8 rows in parallel so that mutually different poles are adjacent, and moreover the magnets 270, 271 having same pole are opposed, gap-repulsion magnetic force characteristics is represented by a curve 272. Numeral 273 is a characteristics curve of the case where the magnets are in 6 rows, and numeral 274 is a characteristics curve of the case where the magnets are in 4 rows, and numeral 275 is a characteristics curve of the case where the magnets are in 2 rows. As will be obvious from the foregoing characteristics curves, the curve of the characteristics curve becomes steep as the number of rows of the magnets is increased and magnetic poles are increased. Namely, although, the repulsion magnetic force becomes big, the attenuation of the repulsion magnetic force relative to the widening of the gap becomes remarkable. This phenomenon leads to a conclusion that in case a condition where a predetermined load of a degree that the magnet 270 is not in contact with the magnet 271 is applied in downward direction to the magnet 270 is changed to a condition where the load is changed in load decreasing direction, the change of the gap of the magnet 270 to the magnet 271 becomes small if the number of rows of the magnets 270, 271 is on the increase. The magnetic members are such that when they are separated farther from the opposed magnetic pole surfaces, magnetic flux density is attenuated, but if the number of rows of the magnets is bigger, the attenuation is remarkable as compared with 7 GB 2 120 393 A 7 the number of rows of the magnets is small. Accordingly, when one magnet is floated relative to the other magnet by the repulsion magnetic force, and the load applied to the one magnet toward the other magnet is changed from a maximum value to a minimum value, in order to minimize the change of the opposed gap of a pair of magnets, the rows of the magnets may be increased in parallel direction.

This embodiment is based on the foregoing 75 concept.

The construction of the embodiment is described by referring to Fig. 18.

Numeral 276 is a drawing board and is mounted on a drawing bench so that it can be set at a given inclined angle between an almost upright condition to a horizontal condition relative to the floor surface. Numeral 277 is a horizontal rail made of drawing form aluminum which is fixed to an upper edge portion of the drawing board 276 by means of a vice type fixture 278, and a space portion 279 for insertion of magnetic member is formed over an entire length of the horizontal rail in its longitudinal direction, and an upper wall portion 279a forming the space portion 279 is formed to a thickness that allows the magnetic force to work on the outside sufficiently. Numeral 280 is a bandlike iron plate inserted and disposed in the space portion 279, and the under surface of the iron plate is in tight contact with the bottom surface of the space portion 279, and both side portions of the iron plate 280 are in tight fitting to grooves 281, 282 formed over an entire length of the space portion 279 at the lower end of the side wall forming the 100 space portion 279.

Numeral 283 is 8 pieces of bandlike magnet rubbers which are press fitted into the space portion 279 over its entire length, and the magnet rubbers are arranged in parallel so that different 105 poles are adjacent, and each under surface is attracted to the iron plate 280. Numeral 284 is a horizontal cursor, and a plurality of horizontal rollers 285 which are rotatably and pivotally supported on the horizontal cursor are in contact with one surface of a pair of perpendicular rail surfaces formed on the horizontal rail 277 along in its longitudinal direction, and one or a plurality of horizontal rollers 286which are rotatably and pivotally supported on the horizontal cursor 284 are in contact with another surface of the perpendicular rail surfaces. Numeral 287 is a plurality of vertical rollers which are rotatably and pivotally supported on the horizontal cursor 284, and these surfaces are in contact with the 120 horizontal rail surface 288 formed on the horizontal rail 277. Numeral 289 is one or a plurality of safety rollers which are rotatably and pivotally supported on the horizontal cursor 284, and being opposed to the horizontal rail surface 290 of the horizontal rail 277 at a proper gap.

Numeral 291 is a vertical rail, and a vertical bracket 292 is fixed to the vertical rail 29 1, and the vertical bracket 292 is pivotally (293) and rotatably supported on the horizontal cursor 284 centering around an axis horizontal to the surface of the drawing board 276. Numeral 294 is a horizontal portion formed on the vertical bracket 292, and 8 pieces of magnet rubber 295 are arranged on the horizontal portion in parallel as illustrated so that mutually different poles are adjacent. A plurality of magnetic pole tracks are formed on the magnetic pole surfaces of the 8 pieces of magnet rubbers 283, 295. A magnet rubber group 295 at the side of the bracket 292 and a magnet rubber group 283 at the side of the horizontal rail 277 are disposed in such a way that the repulsion magnetic force is worked as the same pole surfaces are opposed mutually and the vertical bracket 292 is floated relative to the horizontal rail 277 by the repulsion magnetic force.

The vertical bracket 292 constitutes the traveling member, and the horizontal rail 277 constitutes the guiding member.

Next, an operation of this embodiment is described.

When the handle of the head is grasped by the hand and is applied with a pressure in a given direction parallel to the surface of a drawing board 276, the horizontal cursor 284 is shifted along the horizontal rail 277, and the vertical cursor is shifted along the vertical rail 29 1, and the head can be shifted to a desired position on the drawing board 276 by the shifting thereof. When the drawing board 276 is inclined from the horizontal condition to the rising direction, for example, to 801 relative to the floor surface, the load applied on the vertical bracket in perpendicular direction to the surface of the drawing board 276 is greatly decreased as compared with the horizontal condition of the drawing board 276. However, the opposed gap of the magnetic pole surface of the horizontal rail 277 and the magnetic pole surface of the bracket 292 side is not widely changed according to the reduction of the load, and the change is minimal quantity. This is caused by the fact that the magnetic pole surface is formed by a plurality of parallel magnet rubbers. Accordingly, the horizontal cursor 284 is merely slightly inclined in anti-clockwise direction in Fig. 27 centering around the vertical rollers 287 even if the vertical bracket 292 is changed in upper direction to the surface of the drawing board 276 so that parallelness of the surfaces of the horizontal rollers 285, 286 to the perpendicular rail surface can be maintained by the gap between the horizontal rollers 285, 286 and the shaft supporting the rollers, and the surfaces of the horizontal rollers 285, 286 are not inclined to the perpendicular rail surface. Also, a rising quantity of the safety rollers 289 to the horizontal rail surface 290 which is accompanied by the rising of the drawing board 276 is minimal quantity.

Next, another embodiment is described by referring to Fig. 19.

Numeral 300 is a vertical cursor, and magnets 301, 302, 303 and 304 consisting of 4 pieces of magnet rubbers are disposed on top and bottom 8 GB 2 120 393 A 8 surfaces of a horizontal portion of the rising portions formed at both sides of the vertical cursor. The respective magnet rubbers of the magnets 301, 302, 303 and 304 are arranged in parallel so that mutually different poles are adjacent. A plurality of rows of magnetic pole tracks are formed on the magnetic pole surfaces of the magnets. Numerals 305,306, 307 and 308 are magnets having a plurality of rows of magnetic pole tracks which are arranged on a vertical rail 309 to be opposed to the magnets 301, 302, 303 and 304, and each of the magnets consists of 4 pieces of magnet rubbers, and the magnet rubbers are arranged in parallel so that mutually different poles are adjacent. The magnets 301 and 305, 302 and 306, 303 and 307, and 304 and 308 are such that the same pole surfaces are opposed and the vertical cursor 300 is floated relative to the vertical rail 309 by the repulsion magnetic force working between them. Numeral 310 is a guide roller for prevention of traverse vibration.

In the foregoing construction, when the drawing board 276 is changed from the horizontal condition to the perpendicular condition, the load of the vertical cursor 300 working in the perpendicular direction to the vertical rail 309 is decreased remarkably.

However, there is not much change in the floating gap between the magnets 301, 303 and the magnets 305, 307. Accordingly, there is no need of providing a bigger space in the vertical rail 309 for accommodating the magnets 301, 302, 303 and 304, and the vertical rail 309 can be made in compact form. The vertical cursor 300 constitutes 100 the traveling member, and the vertical rail 309 constitutes the guiding member. By the way, the construction of dividing the magnetic pole surface of the magnet into a plurality of rows of magnetic pole tracks is not particularly limited to the embodiment, and a plural rows of magnetic pole structure may be employed in which the magnets which are provided in the opposed portion of the horizontal cursor (traveling member) and the horizontal rail (guiding member).

Next, an embodiment of preventing the deflection of the horizontal rail is described by referring to Figs. 21, 22 and 23.

Numeral 312 is a drawing board, and numeral 313 is a long plate member whose side is L shape, and a long support portion 312a is integrally formed on a perpendicular portion of the long member, and a magnet consisting of 5 pieces of magnet rubbers wherein mutually different poles are adjacent is fixed to the upper 120 surface of the support portion 313a, and the magnetic surface is formed by the magnet rubber group. Plate members 315, 316 are fixed to both ends of the perpendicular portion of the member 313, and a vice type fixture is formed at both end 125 portions of the member 313 by the plate members 315, 316 and a horizontal portion of the member 313, and a screw bar 317 screwed to thread holes formed at both ends of the horizontal 65 portion, and the long member 313 is fixed to both 130 ends of the upper edge portion of the drawing board 312. Numeral 318 is a horizontal rail, and a T-shaped groove 319 is formed at side portion of the horizontal rail, and a flange portion 320a of a shaft 320 is disposed in the T-shaped groove 319. The shaft 320 is fitted and inserted into a lateral through hole 321 formed at an end portion of the long member 313, and a tapered tip of a screw lever 323 screwed to a vertical thread hole 322 formed on the member 313 is in pressure contact with an inclined surface 320b of the shaft 320, and one end portion of the horizontal rail 318 is fixed to one end portion of the member 313 by the pressure contact force. The other end portion of the horizontal rail 318 is fixed similarly to the other end portion of the member 313 by the same construction mentioned above. Numeral 324 is a horizontal cursor, and horizontal guide rollers 325, 326 pivotally and rotatably supported on the horizontal cursor are in contact rotatably with the perpendicular rail surface formed over an entire length of the horizontal rail 318 in its longitudinal direction. A vertical guide roller 327 rotatably and pivotally supported on one side portion of the horizontal cursor 324 is in contact with the horizontal rail surface formed along the horizontal rail along its longitudinal direction, and a vertical safety roller 328 rotatably and pivotally supported on the other side portion of the horizonhal cursor 324 is opposed at a proper gap to the horizontal rail surface of the horizontal rail 314. Numeral 329 is a vertical rail, and a bracket 330 is fixed to an end portion of the vertical rail, and a lower portion of the bracket 330 is pivotally (33 1) supported on the horizontal cursor 324 so as to be rotatable centering around an axis parallel with a longitudinal direction of the horizontal rail 318. Numeral 332 is a magnet consisting of 5 pieces of magnet rubber group disposed on the lower surface of a projecting member 333 formed on the bracket 320 so that mutually different magnetic poles are adjacent, and the magnet 332 is disposed to the magnet 314 in such a way that the same polarity surfaces are opposed in parallel, and the bracket 330 is floated relative to the member 313 by the repulsion magnetic force working between the magnets 332 and 314. Numeral 325 is a vertical cursor mounted shiftably on the vertical rail 329, and a head 336 is connected to the vertical cursor by means of a hinge member, and straightedges 337, 338 are detachably fixed to a straightedge mounting plate of the head 336. Numeral 339 is a bracket fixed to a tall portion of the vertical rail 329, and a magnet is fixed to the lower surface of the bracket, and the magnet is opposed to a magnet disposed at the lower edge portion of the drawing board 312, and the tail portion of the vertical rail 329 is floated relative to the surface of the drawing board 312 by the repulsion magnetic force working between the magnet 340 and the magnet disposed at the side of the bracket 339.

In the foregoing construction, the load of downward direction by the dead weight of the I 9 GB 2 120 393 A 9 vertical rail 329 at one end portion of the vertical rail 329 is applied to the support portion 313a of the long member 313 by means of the 332, 314, and the load is not applied on the horizontal rail 318. When the head 336 is applied with pressure in a given direction parallel to the surface of the drawing board 312 by the hand, the horizontal cursor 324 is guided by the perpendicular surface of the horizontal rail 318 and is shifted along the horizontal rail 318, and the vertical cursor 335 is shifted along the vertical rail 329, and the head 336 and the straightedges 337, 338 can be shifted to desired positions on the drawing board 312.

Next, another embodiment of preventing the 80 deflection of the horizontal rail is described by referring to Fig. 24.

Numeral 350 are vice type fixtures (the other is omitted) fixed to both end portions of the upper edge of the drawing board 35 1, and a long member 362 having a length almost same with an entire length of the side surface 351 a of the drawing board 351 is fixed to the fixture 350. Numeral 353 is a horizontal cursor, and a vertical guide roller 354 and horizontal guide rollers 355, 356 are rotatably and pivotally supported on the horizontal cursor 353, and the rollers are in contact with the opposed rail surface as shown in the drawing, and a safety roller 357 is opposed at a proper gap to the horizo6tal rail surface of the horizontal rail 358. Numeral 359 is a magnet fixed to an entire length of the member 352 along a shifting line of a connecting portion of the horizontal cursor 353 and a bracket 360 on the upper surface of the member 352, and the magnet 359 is opposed to a magnet 362 fixed to the lower surface of the horizontal cursor 353 which is positioned immediately below the connecting portion 361, and the bracket 360 is floated relative to the member 352 by the repulsion magnetic force working between the magnets 362 and 359.

In the foregoing construction, the downward load by the dead weight of the vertical rail 329 and the dead weight of the horizontal cursor 353 110 at one end portion of the vertical rail 329 is applied to the long member 352 through the magnets 359, but it is not applied to the horizontal rail 358.

Next, another embodiment is described by 115 referring to Fig. 25.

Numeral 370 is a rail member fixed integrally to the end surface of upper edge of the drawing board 371 over its entire length, and a magnet 55. 372 is fixed to the upper surface of the rail 120 member 370 over an entire length in its longitudinal direction. Numeral 373 is a horizontal rail whose both end portions are fixed to the side surface forming the T-shaped groove 374 of the rail member 370, and the lower portion of a bracket 376 fixed to one end of the vertical rail 375 is rotatably and pivotally (377) supported on the horizontal rail. Numeral 378 is a projecting member projected on the bracket 376, and a magnet 379 is fixed to the lower surface of the projecting member in opposition to the magnet 372, and the bracket 376 is floated relative to the rail member 370 by the repulsion magnetic force of the magnets 372, 379. Accordingly, the downward load by the dead weight of the vertical rail 375 is not applied to the horizontal rail 373, and is applied to the rail member 370 integral with the drawing board 371 by means of the repulsion magnetic force of the magnets 372, 379, Next, another embodiment of preventing the deflection of the horizontal rail is described by referring to Figs. 26, 27.

Numeral 380 is a drawing board to which a bandlike magnet board 382 is fixed in horizontal direction over entire upper surface of a drawing board substrate 381 made of wood, or resin or paper core, and a strong magnetic force region is formed by a proper range A at the upper edge portion side of the drawing board 380 and a proper range B at the lower edge portion side of the drawing board 380. The upper surface of the drawing board 380 in the range A is set with a proper step to the other flat surface, and a magnet 385 fixed to the lower surface of a projecting member 384 of a bracket 383 is opposed to the magnet 382 of the range A, and the bracket 383 is floated relative to the drawing board 380 by the repulsion magnetic force of the magnets 382, 385. Numeral 386 is a horizontal rail and is fixed to the side of the upper edge of the drawing board 380 by means of a vice type fixture 387. In the magnetic force region in the range B of the lower edge portion of the drawing board 380, the magnet fixed to the tail portion of the vertical rail 387 is opposed to the magnet 382 in the range B so that the magnet is repulsed in a direction of floating relative to the drawing board 380.

By the way, the foregoing embodiment shows the energization of the vertical rail in a direction of floating relative to the surface of the drawing board by utilizing the repulsion magnetic force of the magnets, but it is possible to energize the vertical rail in the floating direction by utilizing the attracting force of the magnets.

Next, another embodiment of the invention is described by referring to Figs. 28 through 32.

Numeral 390 is a drawing board fixed to a support frame of the drawing board of a drawing bench 39 1, and a long stationary rail 393 is fixed to the upper edge portion of the drawing board in almost lateral width of the drawing board 390 by a vice type fixture 392, and magnets 394, 395 made of 3 pieces of magnet rubbers whose mutually different poles are adjacent along the rail in its longitudinal direction are fixed to the upper surface of the stationary rail 393. Numeral 396 is a horizontal rail of almost same length with the stationary rail 393 disposed on the stationary rail 393, and magnets 397, 398 made of 3 pieces of magnet rubbers whose mutually different poles are adjacent are fixed to the lower surface of the horizontal rail along its longitudinal direction.

Numerals 399, 400 are traverse vibration control GB 2 120 393 A 10 rail surfaces formed along the horizontal rail 396 in its longitudinal direction, and side shape thereof is an arched concave shape. A plurality of the convex curved surfaces of the horizontal guide rollers 401 which are rotatably and pivotally 70 supported on the stationary rail 393 are in rotatable contact with the rail surface 399, and a plurality of the convex curved surfaces of the horizontal guide rollers which are rotatably and pivotally supported on the stationary rail 303 are 75 in rotatable contact with the rail surface 400. The horizontal rail 396 is guided by the guide rollers 401 and is capable of shifting along the stationary rail 393 in its longitudinal straight line direction.

The same pole surface of the magnet 397 is opposed to that of the magnet 394, and the same pole surfaces of the magnet 398 is opposed to that of the magnet 395. The horizontal rail 396 is floated relative to the stationary rail 393 by the repulsion magnetic force working between the magnet rubbers 394, 397 and 395, 398.

Numerals 402, 403 are a plurality of vertical safety rollers which are rotatably and pivotally supported on both side portions of the horizontal rail 396, and these surfaces are opposed to the 90 upper surface of the stationary rail 393 at a gap shorter than the floating gap of the horizontal rail 396 to the stationary rail 393. Numerals 404, 405 are magnets made of a pair of magnet rubbers fixed on the upper surface of the stationary rail 393 over an entire length in its longitudinal direction, and magnets 404 and 406 made of a pair of magnet rubbers fixed to both side portions of the lower surface of the horizontal cursor 405 are opposed to the magnets 404, 405, and the horizontal cursor 405 is floated relative to the horizontal rail 396 at a predetermined gap by the repulsion magnetic force working between the magnets 404 and 406, 405 and 407. Numeral 408 is a horizontal guide roller which is rotatably and pivotally supported on the horizontal cursor 405, and the convex curved surface of the guide roller is in contact rotatably with the concave curved surface of the rail surface 408 of a pair of rail surfaces 408, 409 formed on the horizontal rail 396. The rail surface 409 is in contact rotatably with the convex curved surface of the horizontal guide roller (not shown) which is rotatably and pivotally supported on the horizontal cursor 405. The 115 horizontal cursor 405 is guided by the rail surfaces 408, 409, and can be shifted along the horizontal rail 396 in a straight line direction.

Numerals 410, 411 are vertical safety rollers which are rotatably and pivotally supported on both side portions of the horizontal cursor 405, and these surfaces are opposed to the upper surface of the horizontal rail 396 at a gap shorter than the magnetic floating gap of the horizontal cursor 405 to the horizontal rail 396. A platelike stopper 412 is provided at the I eft end of the horizontal rail 396, and an elastic body 413 is provided at the end portion of the side of the horizontal rail 396. Numeral 414 is a pressure member fixed to the end portion of the side of the 130 horizontal cursor 405, and the elastic body 413 is set so as to be positioned on a shifting line at the inside surface of the pressure member 414. Numeral 415 is a pair of mounting plates which are set at a proper gap at the left side of the horizontal cursor 405, and a bracket 417 fixed to one end of the vertical rail 416 is supported on a shaft 418 rotatably. The vertical rail 416 is set at right angles to the horizontal rail 396, and the horizontal rail 416 can be rotated in a perpendicular direction to the surface of the drawing board 390. A vertical cursor 419 is slidably mounted on the vertical cursor 416, and a head 420 is mounted on thevertical cursor 419 by means of a hinge member, and straightedges 421, 422 are detachably mounted on the straightedge mounting plate of the head 420. Numeral 423 is a lateral lever mounted at the side of the head 420 by projecting in right angle direction, and a tail portion roller 424 is rotatably mounted on the vertical rail 416 centering around an axis parallel to the vertical rail 416, and the tail portion roller 424 is mounted on a guide rail 425 fixed to the side of the lower edge of the drawing board 390 so as to be rotatable.

Next, an operation of the embodiment is described.

When the vertical rail 416 is shifted in left direction on Fig. 28, the horizontal rail 396 is shifted in left direction in a condition where the horizontal cursor 405 is floated relative to the horizontal rail along thereof, and the tail portion roller 424 is rotatably travelled in left direction on the surface of the guide rail. When the vertical rail 416 reaches an almost left end of the drawing board 390, the pressure member 414 contacts the elastic body 413, and the horizontal rail 396 is interlocked in left direction with the horizontal cursor 405 by the frictional force of the elastic body 413 and the pressure member 414 in floating condition relative to the stationary rail 393, and is pushed out in left direction along the stationary rail 393. When the horizontal rail 396 is shifted in a predetermined distance in left direction, the shifting in left direction is engaged by a stopper mechanism (not shown). Even if the horizontal rail 396 is engaged, when the horizontal cursor 405 is shifted in left direction, the pressure member 414 is shifted in left direction while resisting to the resilience of the elastic body 413 and applying the pressure to the elastic body 413, and an end portion of the horizontal cursor 405 contacts the stopper 412 of the horizontal rail 396. At this time, the elastic body 413 is in pressure contact with the side surface of the pressure member 414. As described above, when the horizontal cursor 405 is shifted to the end of the drawing board 390 in left direction until the horizontal cursor 405 is engaged with the stopper 412 of the horizontal rail 396, the vertical rail 416 is brought to the side of the drawing board 390, and the straightedge 422 can be shifted to the left end of the drawing board 390, thereby eliminating the dead space of the drawing board 390. When the horizontal cursor 405 is shifted in 11 GB 2 120 393 A 11 right direction, the horizontal rail 396 is interlocked with the horizontal cursor 405 by the resilient frictional force of the elastic body 413 against the inside surface of the pressure member 414, and is shifted in right direction, and the 70 stopper 412 contacts the end portion of the stationary rail 393. If the horizontal cursor 405 is further shifted in right direction, the pressure member 414 is slid in right direction along the elastic body 413 by resisting to the resilient frictional force with the elastic body 413, and the resilient contact condition of the elastic body 413 and the pressure member 414 is released. During the traveling of the horizontal rail 396 along the stationary rail 393, the large load is applied downwardly to the horizontal rail 396, and the horizontal rail 396 is descended by resisting to the repulsion magnetic force, and as a result, the surfaces of the safety rollers 402, 403 contact the upper surface of the stationary rail 393, and the magnets 397, 398 and 394, 395 are prevented from coming into contact. Also, during the traveling of the horizontal cursor 405 along the horizontal rail 396, the large downward load is applied to the horizontal cursor 405, and the horizontal cursor 405 is descended by resisting to the repulsion magnetic force, and as a result, the surfaces of the safety rollers 410, 411 come into contact with the upper surface of the horizontal rail 396, and the magnets'406, 407 and magnets 95 404, 405 are prevented from coming into contact.

When the inclined angle of the drawing board 390 is changed, the load applied from one end portion of the vertical rail 416 to the horizontal cursor 405 in downward perpendicular direction to the surface of the drawing board 390, and the opposed gaps of the magnets 406, 407 and magnets 404, 405 are changed by the change of load, and the horizontal cursor 405 is inclined to the horizontal rail 396 centering around an axis parallel to the longitudinal direction of the horizonal rail 396. The guide roller 408 is displaced along the concave curved surface of the 46 rail surface 408 by being interlocked with the inclination of the horizontal cursor 405, and the tight contacting condition of the rail surface 408 and the guide roller 408 is retained. Accordingly, there is no apprehension that the eccentric load is applied to the guide roller 408 by the inclination of the horizontal cursor 405. The case of the horizontal rail 396 and the stationary rail 393 is similar, and the opposed gaps of the magnets 397, 398 and magnets 394, 395 are changed, and even if the horizontal rail 396 is inclined to the stationary rail 393 centering around an axis in its longitudinal direction, the tight contacting condition of the guide roller 401 and the rail surface 399 is retained.

When the invention is put to Work, a mechanism of supporting the tail portion of the vertical rail 416 on the drawing board 390 and outside position of the drawing board is not limited particularly to the construction of the lateral lever 423 and the tail portion roller 424 shown in the drawing. Also, when both the horizontal rail 396 and the vertical cursor 405 are completely floated, the movement of the vertical rail 416 becomes light which is most desirable one but either of the rail or cursor may be completely floated. When only the horizontal cursor 405 is completely floated, the movement of the horizontal rail 396 becomes heavy so that an advantageous point is derived that the horizontal rail 396 is not easily moved during the shifting of the horizontal cursor 405. Also, when only the horizontal rail 396 is completely floated, the movement of the horizontal cursor 405 becomes heavy but as the movement of the horizontal rail 396 becomes light, a difference between the force required for shifting only the horizontal cursor 405 and the force required for interlocking the horizontal cursor 405 with the horizontal rail 396 becomes small, and as a result, these forces are just balanced, thereby deriving an advantageous point of easy manipulation for shifting of the head. Also, as shown in Fig. 3 1, the safety rollers are not required to be provided, and furthermore, as shown in Fig. 32, horizontal guide rollers 427, 428 are provided on the horizontal cursor 405, and the vertical guide rollers are mounted and contacted on the upper surface of the horizontal rail 396, and there may be provided a construction in which the pressure applied on vertical guide rollers 427, 428 is decreased by the repulsion magnetic force of the magnets 404, 406, and magnets 405, 407, and also vertical guide rollers 429, 430 are provided on the horizontal rail 396, and the vertical guide rollers 429, 430 are mounted and contacted on the upper surface of the stationary rail 393, and there may be provided a construction in which the pressure applied on the vertical guide rollers 429, 430 is decreased by the repulsion magnetic force of the magnets 394, 397, and magnets 395,398.

Next, another embodiment is described by referring to Fig. 33.

Numeral 404 is a horizontal rail made of aluminum drawn material fixed to the upper edge portion of the drawing board 440 by means of a vice type fixture 442, and a concave fitting portion 443 for insertion of magnet is formed over an entire length of the horizontal rail 441 in its longitudinal direction. Numeral 444 is a bandlike iron plate inserted and disposed in the concave fitting portion 443, and the lower surface of the iron plate is in tight contact with the bottom surface of the concave fitting portion 443, and both side portions of the iron plate 444 are tightly fitted to grooves 445, 446 formed on the lower end of the side wall forming the concave fitting portion 443 over an entire length of the concave fitting portion 443. Numeral 447 is a magnet consisting of 5 pieces of bandlike magnet rubbers which is press fitted into the concave fitting portion 443 over its entire length, and different poles thereof are disposed in parallel so as to be adjacent to each other and each lower surface is attracted to the iron plate 444. Both 12 GB 2 120 393 A 12 side portions of the magnet 447 are fitted to the 55 grooves formed in the concave fitting portion 443. Numeral 448 is a cover plate disposed over an entire length of the concave fitting portion 443, and a projecting portion 448a of the cover plate 448 is in contact resiliently with the upper 60 surface of the magnet 447, and its both side portions are in contact resiliently with horizontal surfaces 443a, 443a of the concave fitting portion 443. Numeral 449 is a horizontal cursor, and horizontal guide rollers 450, 451 which are rotatably and pivotally supported on the horizontal cursor 449 are in contact with the perpendicular rail surface formed along the horizontal rail 441 in its longitudinal direction.

Numeral 452 is a vertical guide roller which is rotatably and pivotally supported on the horizontal cursor 449, and its surface is in contact with the horizontal rail surface formed on the horizontal rail 441 in its longitudinal direction.

Numeral 453 is a safety roller and is opposed at a proper gap to the horizontal rail surface formed over an entire length of the horizontal rail 441 in its longitudinal direction. Numeral 454 is a vertical rail, and its one end is fixed to a bracket 455, and the lower portion of the bracket 455 is pivotally supported 457 on the rising portion of the horizontal cursor 449 so as to be rotatably centering around an axis parallel to the horizontal rail 441. Numeral 458 is a magnet made of 5 pieces of bandlike magnet rubbers fixed to the lower surface of a projecting member 459 formed 85 on the bracket 455, and the magnet rubbers are disposed so that mutually different poles are adjacent, and also the same pole surfaces of the magnet 458 and the magnet 447 are arranged to be opposed. The bracket 455 is energized in a floating direction relative to the horizontal rail 441 by the repulsion magnetic force working between the magnets 447 and 459. This embodiment is formed in such a way that all the load applied to the bracket 455 is received by the repulsion magnetic force working between the magnets 447 and 458 but it may be constructed in such a way that a part of this load is received between the vertical guide roller 452 at the side of the horizontal cursor 449 and the horizontal rail 100 surface.

By the way, it may be constructed in such a way that the magnet is press fitted to the vertical rail 454 in a similar construction with the horizontal rail 441 shown in Fig. 33 and ther vertical cursor, namely, the traveling member is floated relative to the vertical rail 454 by the magnetic force. When the dusts are adhered to the surface of the magnet 447, the cover plate 448 is pulled out from the concave fitting portion 443 along the concave fitting portion 443 in its longitudinal direction, and thereafter the surface of the magnet 447 is cleaned.

Claims

1. A rail type universal parallel ruler device, comprising a drawing board, a horizontal rail mounted on the drawing board, a horizontal cursor mounted on the horizontal rail shiftably along the horizontal rail, a vertical rail the upper portion of which is journalled on a shaft by the horizontal cursor rotatably in a plane perpendicular to the surface of the drawing board, a vertical cursor shiftably mounted on the vertical rail, and a head connected to the vertical cursor, wherein a first magnetic member is disposed over substantially the entire length of the horizontal rail in the longitudinal direction, and a second magnetic member is disposed on the horizontal cursor in opposition to the first mentioned magnetic member, and the magnetic force working between the first and the second magnetic members is caused to work on the journalled portion of the vertical rail and the horizontal cursor in the upward perpendicular direction relative to the surface of the drawing board.

2. A rail type universal parallel ruler device as claimed in Claim 1, wherein the first and the second magnetic members comprise a pair of magnetic members for providing the magnetic force of downward perpendicular direction relative to the surface of the drawing board to the horizontal cursor at a position apart from the journalled portion and at least a pair of magnetic members for providing the magnetic force of the upward perpendicular direction relative to the surface of the drawing board to the horizontal cursor at an intermediate position of the journalled portion and the magnetic members.

3. A rail type universal parallel ruler device as claimed in Claim 1, wherein the first and the second magnetic members are composed of at least a pair of magnetic members for providing the magnetic force of upward perpendicular direction relative to the surface of the drawing board to the journalled portion.

4. A rail type universal parallel ruler device according to Claim 1, substantially as herein described with reference to, and as shown in, any of the figures of the accompanying drawings.

Printed for Her Majesty's Stationary Office by the Courier Press, Leamington Spa, 1983. Published by the Patent OffiGe, 25 Southampton Buildings, London, WC2A 1AY, from which copies maybe obtained.