JPS61104898A - Scale balancer in universal parallel rule - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a scale balancing device for a universal parallel ruler.

[Conventional technology]

As this type of apparatus, those shown in Japanese Utility Model Application Publications No. 59-131893, No. 59-131894, and No. 59-131895 are known.

The above publication states that when the connection point of the elastic means to the rotating body is moved to the swing fulcrum of the elastic means for applying a balancing force to the rotating body linked to the scale, the elasticity of one elastic means becomes zero. discloses a technical idea that the scale can be perfectly balanced by setting the initial elasticity of the elastic means.

The elastic means includes a coil spring, a rope, a cylindrical elastic device, a curved spring, and the like.

[Problem that the invention seeks to solve]

In order to achieve the above-mentioned perfect scale balance, if a conventional elastic means is used, the device becomes large and unsuitable for miniaturization. An object of the present invention is to provide a balance device suitable for downsizing.

[Means to solve problems]

In order to achieve the above object, the present invention provides a head 16 that is movable to any position on the drawing board 2 while maintaining a predetermined orientation.
, a scale mounting plate 28 rotatably attached to the support substrate 18 side of the head 16, and a scale 30.32 attached to the scale attachment plate 28; A substantially middle portion of the support arm 54 is rotatably supported, and one side of the support arm 54 is attached to an eccentric portion of a rotary body 38 that is interlocked with the scale mounting plate 28, so that displacement of the eccentric portion in the diametrical direction of the rotary body 38 is supported. The rotating body 3 is slidably engaged with the rotating body 38 so that a biasing force is applied to the rotating body 38 in a direction opposite to the rotation direction due to the weight of the scale 30, 32, etc. of the rotating body 38.
A spring 5 is provided between the eccentric portion of 8 and the other side of the support arm 54.
The initial elasticity of the spring is set so that when the connection point of the spring 56 with the rotating body 38 is moved onto the center of rotation of the support arm 54, the elasticity of the spring becomes approximately zero. It is characterized by the fact that

[Effect]

The head 16 is held stationary on the inclined drawing board 2, and the scale 30.
32 is in a free rotation state with respect to the head support substrate 18 side, the weight of the scale 30, 32, etc. causes the rotating body 3
Rotational torque in the direction of gravity is generated at 8, and the scale is 30°3.
2 tries to rotate in the falling direction along the slope of the drawing board 2. On the other hand, the tensile force of the spring 56 connected to the support arm 54 acts on the -rolling body 38, and rotational torque is generated in the rotating body 38. This rotational torque cancels out the rotational torque of the rotating body 38 in the direction of gravity, and the scales 30 and 32 are in a balanced state. The pivot point is set at a constant position in conjunction with the rotation of the rotating body 38.

〔Example〕

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

Reference numeral 2 denotes a drawing board, which is fixed to a support frame of a tiltable drafting table so that it can be fixed at a desired inclination angle between horizontal and vertical. 4 is a horizontal rail arranged on the upper side of the drawing board 2, and a horizontal cursor 6 is movably attached to this rail. The upper end of the vertical rail 8 is connected to the horizontal cursor 6. The lower end of the vertical rail 8 is movably mounted on the drawing board 2 via the tail portion 9 opening. 12 is a vertical cursor movably attached to the vertical rail 8, and the head 1 is attached to this via a known double hinge mechanism 14.
Six support 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 circumferential surface of which is rotatably fitted into the inner circumferential surface of the multi-shaft 20.

A mounting plate 24 is fixed to the upper part of the main shaft 22 with a nut, and a handle 26 is fixed to the mounting plate 24. A scale mounting plate 28 is attached to the lower end flange of the main shaft 22.
is fixed, and the scale 30.3 is fixed to the scale mounting plate 28.
2 is fixed. 34 is a tubular body fixed to the mounting plate 24, and a first rotating body 36 is attached to the outer peripheral surface of the tubular body 34.
It is fixed by a screw 3q so that the rotation angle can be adjusted with respect to the main body. A gear 37 is provided at the lower pulley portion of the rotating body 36.
is formed. 38 is a tubular second rotating body;
The outer peripheral portion is rotatably supported by a support substrate 18 by a ball bearing. A timing belt 48 is passed between the teeth 45 formed on the pulley portion of the second rotating body 38 and the air 37 of the first rotating body 36 . 4
Reference numeral 2 denotes a threaded shaft installed in the diametrical direction of the rotating body 38. A molding 44 is screwed onto this shaft, and a bridge member 46 is fitted into a recessed portion of the molding 44. The bridge member 46 is supported by a linear guide along the screw shaft 42 of the rotating body 38,
The bridge member 46 is configured to move along the screw shaft 42 in conjunction with the molding 44. 50 is a bracket 52
This is a belt tension pulley that is rotatably attached to the

Reference numeral 54 denotes a support arm, which has an L-shaped portion 5 approximately in the center thereof.
4a is vertically provided, and the horizontal portion of the cursor-shaped portion 54a is rotatably supported by a shaft 55 on a portion of the support substrate 18 located below the rotary body 38. A circumferential groove of the shaft portion of the bridge member 46 is fitted into one of the two forked portions 54b of the support arm 54 so as to be slidable along the two forked portions 54b. A coil spring 56 is provided between the pin 57 protruding from the other end of the support arm 54 and the circumferential groove of the shaft of the bridge member 46.
is hung. When the shaft of the bridge member 46, that is, the connection point of the coil spring 56 to the rotating body 38, is moved onto the shaft 55, that is, the rotation center axis of the coil spring 56, the h-period tensile force of the coil springs 5 and 6 is It is set to zero.

Next, the operation of this embodiment will be explained.

When the horizontal scale 30 is approximately parallel to the horizontal rail 4,
The rotational torque about the main shaft 22 due to the weight of the scales 30, 32, etc. of the scale mounting plate 28 is i&large.

At this time, if the rotation 2 of the second rotating body 38 by the spring 56 is inclined, the weight of the scales 30, 32, the scale mounting plate 28, etc. causes the scale mounting plate 28 to rotate around the main axis 22''. A rotation moment is generated in the direction of rotation of the hour hand in FIG. 2. The rotation moment of the scale mounting plate 28 is transmitted to the second rotation body 38 via the first rotation body 36 and the timing belt 48.

On the other hand, the tensile force of the coil spring 56 applies a rotational moment to the second rotating body 38 in a direction that offsets the rotational moment due to the weight of the scale 30 and the like. This allows the scale mounting plate 28 to remain stationary at any rotation angle. Incidentally, as the rotating body 38 rotates, the support arm 54 and the coil spring 56 rotate about the shaft 55.

Next, the distance of the spring connection point to the rotation center of the second rotating body 38 is determined by m! The following describes the operations to be performed.

When the molding 44 is rotated, the molding 44 becomes.

Moving along the screw shaft 42 and interlocking with the molding 44, the bridge member 46 moves on the rotating body 38 in its radial direction. By moving the bridge member 46 along the screw shaft 42, the rotating body 3
The distance between the connection point of the coil spring 56 and the rotation center of the coil spring 8 changes. When the inclination angle of the drawing plate 2 is changed, the value of the load applied to the scale mounting plate 28 due to the weight of the scale 30, 32, etc. changes in accordance with this change. Therefore, when the inclination angle of the drawing board 2 is changed, by adjusting the rotation of the molding 44, the rotating body 3 of the coil spring 56
The amount of eccentricity with respect to 8 is adjusted, and the magnitude of the rotational torque of the second rotating body 38 in the balance direction is adjusted.

〔effect〕

As described above, in the present invention, the swinging fulcrum of the spring is set at the midpoint of the support arm, and one of the support arms and the eccentric part of the rotating body are connected by the spring, so that the swinging fulcrum of the spring is set at the midpoint of the support arm. The device can be brought closer to the rotating body, the spring force of the spring can be used efficiently, and the device can be made smaller.

[Brief explanation of drawings]

FIG. 1 is a sectional view, FIG. 2 is a plan view, FIG. 3 is a sectional view taken along line A-A, and FIG. 4 is a sectional view taken along line B-B. Fig. 5 is an external view of the support arm, and Fig. 6 is a plan view. 16...Head, 18...Support board. 20...Double axis, 22...Main axis, 24...
・Mounting plate, 26...Handle, 28...Scale mounting plate, 34...Pipe body, 36...Rotating body, 38...Rotating body, 42...Screw shaft,
44... Mall, 46... Piece member. 54... Support arm, 55... Axis, 56゛°
・°Coil spring

Claims (1)

[Claims] 1. A head 16 that can be moved to any position on the drawing board 2 while maintaining a predetermined orientation, and the head 1
6, a scale mounting plate 28 rotatably mounted on the support substrate 18 side, and scales 30, 32 mounted on the scale mounting plate 28, a support arm 54 on the support substrate 18 side. , and one of the support arms 54 is attached to an eccentric portion of a rotary body 38 that interlocks with the scale mounting plate 28 so that the eccentric portion is interlocked with the displacement of the rotary body 38 in the diametrical direction. The scales 30 and 32 of the rotating body 38 are slidably engaged with each other.
A spring 56 is suspended between the eccentric portion of the rotary body 38 and the other support arm 54 so that a biasing force acts on the rotary body 38 in a direction opposite to the direction of rotation due to the weight of the rotary body 38. A scale characterized in that the initial elasticity of the spring is set so that when the connection point of the spring 56 with the rotating body 38 is moved above the rotation center of the support arm 54, the elasticity of the spring becomes almost zero. balance device.