JPH0372000B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a universal parallel ruler in which, when the scale is free from the non-rotating member of the head on an inclined drawing board, the scale suddenly moves along the drawing board in the falling direction. This invention relates to a scale balance device that does not rotate.

An object of the present invention is to prevent a tension member for applying a balance force connected to an eccentric part of a rotating body that rotates in conjunction with the scale mounting plate from getting caught on the rotating body even if the scale mounting plate is rotated 360 degrees. This allows the scale to be balanced over a 360 degree range.

The configuration of the present invention will be described in detail below based on embodiments shown in the accompanying drawings.

Reference numeral 2 denotes a drawing board, which is supported by a support frame of a drafting table which can be tilted so that a desired angle of inclination can be set between horizontal and vertical. 4 is a horizontal rail fixed to the upper edge of the drawing board 2, and a horizontal cursor 6 is movably attached to this rail. Said horizontal cursor 6
The upper end of the vertical rail 8 is connected to the upper end of the vertical rail 8. The lower end of the vertical rail 8 is movably placed on the drawing board 2 via a tail roller. 12 is a vertical cursor movably attached to the vertical rail 8, and the head 1 is connected to this via a known double hinge mechanism 14.
Six supporting substrates 18 are connected. A tubular double shaft 20 is fixed to the tube portion of the support substrate 18 with a nut. Reference numeral 22 denotes a tubular main shaft, the outer peripheral surface of which is rotatably fitted into the inner peripheral surface of the multi-shaft 20, and a mounting plate 24 is fixed to the upper part of the main shaft 22. A handle 26 is provided on the mounting plate 24.
is fixed. 28 is a scale mounting plate fixed to the flange of the main shaft 22, and is a tubular body to which the scales 30, 32 are fixed, and a tubular first rotating body 36 is rotatably attached to the outer peripheral surface of this. is fitted. A belt pulley 36a is provided at the lower part of the rotating body 36 and has teeth for a timing belt.
is permanently installed. A screw hole is formed in the side wall of the rotating body 36, and the fixing screw 3 is screwed into the screw hole.
The rotating body 36 is fixed to the tubular body 34 by means 8 . Reference numeral 40 denotes a second rotating body, which is composed of an upper cylinder 40a and a lower cylinder 40b, and the cylinders 40a and 40b are fixed by screws 42 and 44 (see FIG. 5). A feed screw 42 is installed and fixed in the middle part of the rotating body 40 in the diametrical direction of the rotating body 40, and an adjustment molding 44 is attached to the screw 42.
are screwed together. An inner ring of a ball bearing 46 is fitted and fixed in a concave groove formed on the outer periphery of the rotary body 40, and an outer ring of the ball bearing 46 is fitted and supported on the inner wall surface of a hole formed through the support substrate 18. has been done. A pair of curved guide surfaces 46 and 48 are formed on the cylindrical body 40b, and the guide surfaces 4
The outer circumferential curved surface of a bridge member 50 that rotatably fits into the recessed portion of the molding 44 is disposed inside the molding 6 and 48 to face each other. The guide surfaces 46 and 48 prevent the bridge member 50 from falling due to its own weight. A long hole 52 is provided in the bottom wall of the cylindrical body 40b along the feed screw 42, and a protrusion of the bridge member 50 is disposed in the long hole 52 so as to be movable along the long hole 52. The protrusion of the bridge member 50 has a metal terminal 5 connected to one end of a flexible and bendable wire rope 54.
4a is rotatably fitted. The rotating body 40
A belt pulley 40C having timing belt teeth is formed on the outer periphery of the belt pulley 40C, and a timing belt 56 is stretched between the belt pulley 40C and the belt pulley 36a. A coil spring 58 has one end engaged with a screw 60 protruding from the support substrate 18, and the other end connected to the rope 54. A pair of rope guides 62 and 64 are rotatably supported on the support substrate 18, and 66 is a tension pulley for the belt, which is rotatably supported on a bracket fixed to the support substrate 18. Assuming that the metal terminal 54a, that is, one end of the rope 54 is removed from the bridge member 50 and positioned at the end E where the direction of the rope is restricted by the rope guides 62 and 64, the tension on the rope 54 due to the coil spring 58 is exactly zero. The initial position of the coil spring 58 is set, and the coil spring 58 has a spring constant corresponding to the rotational torque generated on the first rotating body 36 due to the weight of the scale mounting plate 28, scales 30, 32, etc. things are being adopted.
Note that the belt pulley 36a is attached to the scale mounting plate 2.
It may be fixed at 8.

Next, the operation of this embodiment will be explained.

In a state where the drawing board 2 is tilted at a predetermined angle and the scale mounting plate 28 is freely rotatable with respect to the support substrate 18, the scale mounting plate 28, the scale 3
A rotational torque T about the main shaft 22 is generated in the first rotating body 36 due to its own weight of 0.0, 32, etc. The magnitude of this rotational torque T and the rotational torque T' acting on the second rotary body 40 due to the elasticity of the coil spring 58 are set to be the same, and their directions are opposite. Therefore, the scale mounting plate 28 is the inclined drawing plate 2.
There is no sudden rotation with respect to the support substrate 18 on the top. By rotating the handle 26, the scale mounting plate 28 can be rotated 360 degrees.
Therefore, the scales 30 and 32 are attached to the support substrate 1 of the head.
Even if the scales 30 and 32 are set at a desired angle with respect to the tilted drawing board 2 and the handle 26 is released, the scales 30 and
Maintain a stable stationary position relative to the head at the top. When the second rotating body 40 rotates as the scales 30 and 32 rotate, the coil spring 5 of the rotating body 40
The rotational torque T' due to 8 changes in a sine curve as shown in FIG. Since the rope 54 does not get caught on the rotating body 40 even if the second rotating body 40 rotates 360 degrees or more, the scale mounting plate 28 can be rotated any number of times.

Next, the operation for adjusting the magnitude of the rotational torque T' will be explained.

When the molding 44 is rotated, the molding 44 moves along the feed screw 42, thereby causing the bridge member 50 to move along the feed screw 42. As the bridge member 50 moves, one end 54a of the rope 54 moves in the radial direction of the second rotating body 40. As the one end 54a of the rope moves relative to the rotating body 40, the distance between the center of the rotating body 40 and the point of action of the spring, that is, the radius as a rotational torque generating element changes, and the rotational torque T' of the rotating body 40 changes. Change.
When the inclination angle of the drawing plate 2 is changed, the value of the load W applied to the center of gravity of the scale mounting plate 28 due to the weight of the scales 30, 32, etc. changes in accordance with this change. When the drawing board 2 is vertical, the above load W
is maximum, and when drawing board 2 is horizontal, the above load W
becomes zero. Therefore, when the inclination angle of the drawing board 2 is changed, by adjusting the rotation of the molding 44, the coil spring 58 is adjusted in response to the rotational torque T generated in the first rotating body 36 by the load W. The magnitudes of the rotational torques T' generated in the second rotating body 40 due to the tensile load can be matched.

Note that the first rotating body 36 and the second rotating body 40
They may be interlocked by meshing gears, and the coupling mechanism between the rotating bodies 36 and 40 is not particularly limited to the illustrated belt transmission mechanism. Further, the second rotating body 40 may be formed of a single cylindrical body 70, as shown in FIG.
Alternatively, the molding 44 may be provided with a rotation stopping mechanism, and the feed screw 42 may be made rotatable so that the molding 44 side moves as the feed screw 42 rotates. In this case, the metal fitting terminal 54a may be directly connected to the molding 44.

As described above, the present invention includes rotatably supporting the outer periphery of the second rotating body on the support substrate of the head, providing a feed screw in the diametrical direction of this rotating body, and providing a molding that is threadedly engaged with the feed screw. Since a spring is connected to the scale so as to move in the direction of the feed screw, it is possible to perform drawing work by rotating the scale more than 360 degrees in a balanced state.

[Brief explanation of drawings]

Fig. 1 is a plan view, Fig. 2 is a plan view, Fig. 3 is a sectional view, Fig. 4 is a sectional view, Fig. 5 is a sectional view taken along line A-A, and Fig. 6 is a sectional view showing another embodiment. 7 are explanatory diagrams. 2...Drawing board, 4...Horizontal rail, 6...Horizontal cursor, 8...Vertical rail, 12...Vertical cursor, 16
...Head, 18...Support board, 20...Multi-axis,
22...Main shaft, 24...Mounting plate, 26...Handle, 28...Scale mounting plate, 32, 33...Scale, 36...First rotating body, 36a...Belt pulley, 40...Second rotating body, 42... feed screw, 44... molding, 50... bridge member, 54...
...Rope, 56...Timing belt, 58...
coil spring.

Claims (1)

[Claims] 1 head 16, a main shaft 22 rotatably supported on the support substrate 18 side of the head 16, and the main shaft 22.
a handle 26 fixed to the upper part of the main shaft 2;
2, and a scale 3 fixed to the scale mounting plate 28.
0.32, a first rotating body 36 is provided on the scale mounting plate 28 side, and an annular second rotating body 40 is provided on the support substrate 18.
is rotatably supported, the rotating bodies 36 and 40 are engaged with each other so as to be interlocked in the rotational direction, and a feed screw 42 is disposed in the diametrical direction on the second rotating body 40, and The molding 44 is threadedly arranged so as to move along the feed screw 42 by rotation relative to the feed screw 42, and the other end of a spring 58, one end of which is attached to the support substrate 18, is attached to the second end of the spring 58.
A scale balance device characterized in that the scale balance device is located on the open side of a rotating body 40 and connected to the molding 44 so as to be interlocked with the movement of the molding 44 along the feed screw 42.