JPS60137696A - Scale balancer for arm type 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 The present invention relates to a scale balancer for an Anim type universal parallel ruler.

Conventionally, flexible parallel rulers that apply the principle of parallel movement of parallelograms include an arm type in which a belt is hung between pulleys installed at the end of the arm, such as this device, and a parallel ruler that uses links to move parallelograms. There is a pantograph type that has a shape.

When comparing the arm type and pantograph type, the arm type requires only the diameter of the pulley to be controlled in order to achieve accuracy, whereas the diameter of the bobbin can be easily achieved through lathe work. .

However, the pantograph type requires highly accurate management of the positions of the four pivot points of the link, and it is important to achieve this accuracy. In addition, in the pantograph type, parallel links are used until they become close to each other and the quadrilateral shape collapses.
When the shape of the link is distorted, an error occurs in the translation accuracy. The arm type is also superior in this respect. However, in terms of strength, a pantograph type link can be made as strong as desired, whereas an arm type belt is moved by being hung on a pulley, so it must be made of a stretchable material. The material will also stretch due to external stress. The elongation of the belt in the above equation appears when the arm-type universal parallel ruler is used on a drawing board in an upright position.

This will be explained with reference to the explanatory diagrams of FIGS. 1 and 2.

When the head 4 is supported by hand to prevent it from falling downward in the vertical plane of the drawing board 2, the weight of the scale 8.10 and the scale mounting plate 12 causes the head 4 to move upward in FIG. , rotational torque is generated in the direction of rotation of the hour hand. This rotational torque is generated by the angle brake 14 or index, mechanism (
The scale is transmitted to the head pulley 16 via a known scale fixing mechanism such as (not shown).

The head pulley 16 has a scale of 8. Due to the rotational torque caused by the weight of lO, etc., the hour hand tends to rotate in the direction of rotation in FIG. 1, and this rotational force is applied to the intermediate pulley 18. head pulley 1
It is transmitted to the belt 20 between 6 and 6. The belt 20 attempts to rotate due to the torque of the pulley 16 in the direction of rotation of the hour hand in FIG. The intermediate pulley 18 is transmitted to the fixed pulley 24 via the belt 22, and is in a non-rotating state, so one side 20a of the belt 20 receives pressure in the direction of extension, and the other side of the belt 20 receives pressure in the direction of contraction. This pressure causes the belt 20 to elongate.

On the other hand, due to the rotational torque of the head pulley 16, the small amount of boot 8 also tends to rotate in the direction of rotation of the hour hand in FIG. A base shaft 30 is fixed to a base 28 fixed to the drawing board 2 via a vise-type fixture 26, and a fixing boot 24 is fixed to the base shaft 30. One side 22a of the belt 22 between the fixed pulley 24 and the intermediate pulley 18 receives pressure in the direction of extension due to the rotational torque of the intermediate pulley 18, and the other side of the belt 22 receives pressure in the direction of contraction,
This causes the belt 22 to stretch. Above belt 20.2
2, the scales 8 and 10 slightly move about the main shaft 6 in the upper direction of the needle in FIG.

By installing zoate type scale balancers at the bottom and bottom of the arm type universal parallel ruler, the problem of the elongation of the bell 1 can be solved. That is, the scale-no mounting plate 1
Place the balance and weight on the opposite side of 2, and the weight of this balance way l- will cause the scale 8. If the rotational torque in the rotational direction of the hour hand in FIG.
The problem of 0.22 elongation does not occur, although it is strange.
□This configuration has the disadvantage that the balance weight increases the weight of the head 4, and a large force is required to support the head 4 from falling by hand. Furthermore, if the head 4 is supported by a known weight type head balance device instead of being supported by hand, the weight for supporting the head must be made heavier by the balance weight. Moreover, when such a configuration is adopted, a large inertial force is generated in the movement of the head 4, resulting in a problem that it is difficult to operate the head 4. There are other scale balancers that use spring force to bias the scale mounting plate 12 in the opposite direction to the direction of rotation due to the weight of the scales 8 and 10, using the head pulley 16 as a fulcrum, but in the case of this configuration, The rotational torque due to the weight of the scales 8 and 10 is transmitted to the head pulley 16 via the balance spring, and eventually the belt 20.2
The problem of growth in number 2 cannot be resolved. However, as mentioned above, the arm-type flexible parallel ruler is superior in that it is easy to process the pulley with high precision, and the shape of the parallelogram does not collapse during operation. If the problem of belt elongation can be solved, it will be possible to provide an arm type universal parallel ruler that is superior to the pantograph type in all respects. SUMMARY OF THE INVENTION An object of the present invention is to provide an arm-type universal parallel ruler for elevation drawing boards that solves the problem of belt elongation.

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

In FIG. 3, reference numeral 30 denotes a drawing board, which is fixed to a support frame (not shown) of a drafting table so that it can be set at a desired angle with respect to the floor. Reference numeral 32 denotes a vise-type fixture fixed to the upper edge of the drawing board 30, and a base 34 is rotatably pivoted to this fixture about an axis 36 parallel to the plane of the drawing board 30.

A reference shaft 38 is fixed to the base 34, and a fixed pulley 40 is fixed to this. A pulley cover 42 is rotatably fitted onto the base shaft 38 via a ball bearing, and one end of a first arm 44 is fixed to the pulley cover 42. 46 is a cylindrical body rotatably fitted to the base shaft 38 via a ball bearing;
The upper end flange of this is fixed to the pulley cover 42,
An intermediate balance cam 48 is fixed to the lower end of the cylinder 46. A cylindrical body 56 is rotatably fitted to the cylindrical body 50 via a ball bearing, a rope pulley 58 is formed at the upper end of the cylindrical body, and a head balance cam 60 is formed at the lower end of the cylindrical body 56. It is formed.

Reference numeral 62 denotes a shaft fixed to the base 34, on the outer peripheral surface of which each intermediate portion of a lever 64.68 is rotatably fitted, and rotatably supported by one end of each lever 64.68. Rollers 70, 74 face the circumferential surfaces of the balance cams 60, 48. Reference numeral 76 is a spring adjustment screw that is slidably inserted into a bearing 78 fixed to the base cover 34, and the threaded portion of the handle 80 is screwed into the two ends of this screw.
A plate member 82 is fixed to the other end of the screw 76. One end of each coil spring 86, 88 is hooked to the U-shaped metal fitting fixed to the plate member 82, and each other end of the coil spring 86, 88 is connected to each other end of the lever 64, 68. are doing. 89 is a boori and the base 34
It is formed coaxially with the group I1llI38.

A pulley cover 90 is connected to the other end of the first arm 44, and the tube portion of the pulley cover 90 is fitted onto the intermediate shaft 92 via a ball bearing so as to be rotatable once. A boss of an intermediate pulley 94 consisting of a double belt pulley is fixed to the intermediate shaft 92, and an endless steel belt 96 is connected between the upper pulley portion of the intermediate pulley 94 and the fixed pulley 40 with an appropriate tension. With John, the stake is being passed. Pulleys 95 and 97 are rotatably mounted on the intermediate shaft 92. The boots IJ 95 and 97 are formed integrally with each other, and the pulley 97 is set to have the same diameter as the pulley 89. 100 is a second arm, one end of which is connected to a lower pulley cover 102;
The tube portion is rotatably fitted to the intermediate shaft 92 via a ball bearing. A rope-like member 106 made of an endless wire rope is passed between the pulley 97 and the pulley 89 with an appropriate tension. Reference numeral 110 denotes a head, and a tube portion of a base plate 112 of this head.

A tube body 114 is fixed, and a tube portion of a pulley cover 116 connected to the other end of the second arm 100 is rotatably fitted to the outer peripheral surface of the upper part of the tube body 114 via a ball bearing. . The head pulley 11 is mounted on the board 112.
2a is formed, and the pulley 112a and the intermediate pulley 9
An endless steel belt 118 is stretched between the four parts with an appropriate tension. A main shaft 120 is rotatably fitted into the tube body 114, and a handle 124 is fixed to the upper part of the main shaft 120.

A scale mounting plate 126 is fixed to the lower end of the main shaft 120, and a scale is removably fixed to the mounting plate 126. Reference numeral 132 denotes a protractor which is rotatably fitted into the tubular body 114, and is releasably fixed to the U plate 112 by a known baseline adjustment device. The scale mounting plate 126 can be fixed to the protractor board 132 in a releasable manner every 15 degrees by operating a known indexing mechanism using an index lever 136.

Further, the scale mounting plate 126 is attached to the angle fixing lever 1.
By operating 40, it can be releasably fixed to the protractor 132 at any angle using a known angle fixing device. 142 is a bottom plate fixed to the scale mounting plate 126, and a member 14 consisting of a cover is attached to this bottom plate.
4 are engaged to interlock in the rotational direction. A pulley 146 is rotatably supported on the inner circumferential surface of the cylindrical portion of the pulley cover 116, and a spiral spring 148 is disposed between the outer circumferential surface of the pulley 46 and the inner circumferential surface of the cylindrical portion of the member 144. is located. One end of the spring 148 is connected to the pulley 1
46, and the other end of the spring 148 is engaged with the cylindrical portion of the member 144. The pulley 146 and the pulley 95 are set to have the same diameter, and a rope-like member 150 made of an endless wire rope is passed between them with appropriate tension.

Next, the operation of this embodiment will be explained.

Grasp the handle 124 of the head 110 with your hand and press the plate 30.
When the head 110 is moved along the surface, the substrate 112 of the head 110 is moved by the belt 118.96 and the pulleys 112a, 9.
By a known parallel movement guide mechanism consisting of 4 and 40,
It translates on the drawing board 30 while maintaining a predetermined angle. Similarly, the pulley 146 is held at a predetermined angle by a parallel movement guide mechanism consisting of a rope-shaped member 150 hung between the pulleys 146 and 95 and a rope-shaped member 106 stretched between the pulleys 97 and 89. 112
It translates on the drawing board 30 with the same movement as . Pulley 146
The rotational force applied from the outside is supported by the fixed pulley 89, and the pulley 146 maintains a predetermined angle. If the scale mounting plate 126 is fixed to the substrate 112 using a known indexing mechanism, the scale will translate on the drawing board 3'0 while maintaining a predetermined angle. When the drawing board 30 is tilted in the upright direction and you release your hand from the handle 124 of the head 110, the 17th arm 44 moves toward the pivot 38 due to its own weight, the weight of the second arm 100, the weight of the head 110, etc. The drawing board 30 tries to rapidly rotate in the falling direction along the inclination of the drawing board 30 . The rotational torque of the first arm 44 in the falling direction about the base shaft 38 is transmitted to the balance cam 48, and the balance force 1148 is applied to the base shaft 38.
Try to rotate around the center. On the other hand, balance cam 48
The roller 74 comes into elastic contact with the cam surface of the first arm 44 due to the tensile force of the coil spring 88, and the balance cam 48 has the first arm 44
A balance rotation torque of approximately the same magnitude is generated in the opposite direction to the rotation torque in the falling direction. This balancing rotational torque cancels out the rotational torque in the falling direction due to the weight of the first arm 44 and the like applied to the balance cam 48, and the first arm 44 maintains a stationary state on the inclined drawing board 30. On the other hand, the second arm 100 moves around the intermediate shaft 92 due to its own weight and the weight of the head 110.
Try to make a sudden turn in the direction of fall. This second arm 100
The rotational torque in the falling direction about the intermediate shaft 92 is transmitted to the head balance cam 60 via the rope-like member 105. The roller 70 comes into elastic contact with the cam surface of the cam 60 due to the tensile force of the coil spring 86, and this elastic contact force.

Depending on the shape of the cam 60, the cam 60 has the head 1.
A balance rotation torque of approximately the same magnitude is generated in the opposite direction to the rotation torque due to the weight of the 10, etc. This balance rotation torque cancels out the rotation torque in the second arm falling direction due to the weight of the head 110 etc. applied to the balance force A60, and the second arm 100
Hold still at the top.

Next, when the fixation of the scale mounting plate 126 to the substrate 112 is released and the scale mounting plate 126 is allowed to rotate freely relative to the substrate 112, the scale is moved to the tube body 112 due to the weight of the scale and the weight of the scale mounting plate 126.
It tries to fall suddenly along the illustration 30 with . Rotational torque of the main shaft 120 connected to the scale due to the weight of the scale, etc. is transmitted to the member 144. Rotational torque for scale balance is generated in the member 144 by the elasticity of a spring 148 with a pulley 146 as a fulcrum. The magnitude of the rotating torque for the scale is set to be approximately the same as the rotating torque in the falling direction of the scale applied to the member 144 due to the weight of the scale, and is set to be approximately the same as the rotating torque in the falling direction of the scale applied to the member 144 and the scale balance. Since the required rotational torques are set in opposite directions, they cancel each other out, and the main shaft 20 maintains a balanced stationary state. Therefore, even if the scale is in a free rotation state with respect to the head substrate 112 on the inclined drawing board 30, it does not suddenly rotate in the falling direction and remains stationary. In addition, the main shaft 114
Since the rotational torque in the scale falling direction is supported by the pulley 146, it is not transmitted to the rear pulley 112a, and therefore
The tensile force due to the rotational torque is almost never applied. This also applies when the scale mounting plate 126 is fixed to the protractor board 132.

As described above, the present invention provides the head with a pulley that moves in the same way as the head pulley, uses this pulley as a fulcrum to apply a balancing force to the main axis of the head, and prevents rotational torque due to the weight of the scale etc. from acting on the head pulley. So,
This has the effect that rotational torque due to the weight of the scale, etc. is not transmitted to the belt hung on the head pulley, and stretching of the belt can be prevented.

[Brief explanation of the drawing]

The figures show preferred embodiments of the present invention, with FIG. 1 being an explanatory front view, the second being an explanatory sectional view, FIG. 3 being a sectional view, and FIG. 4 being a plan view. 2...Drawing board, 4...Head, 6...Main shaft,
8゜10...Scale, 12...Scale mounting plate. 14...Angle brake, 16...Head pulley, 1B...Intermediate pulley, 20...Belt. 22...Belt, 2.4...Fixed pulley, 26
... Vise type fixture, 30 ... Drawing board, 32 ...
・Vise type fixture, 34...Base cover, 36...
...Shaft, 38...Base shaft, 40...Fixed pulley. 42... Pulley cover, 44... First arm. 46...Cylinder body, 48...Intermediate balance cam. 50... Cylindrical body, 52... Rope pulley, 54...
...Balance cam for scale, 56...cylindrical body. '58...Rope pulley, 60...Balance cam for head, 62...Shaft body 64, 66.68...
・・・Leverage, 70, 72, 74... Coro, 76...
・Spring adjustment screw, 78...Bearing, 80...Handle, 82...Plate member, 84.86-. 88...Coil spring, 90...Pulley cover, 92...Intermediate shaft, 94...Intermediate pulley,
96... Steel belt, 98... Idle pulley, 102... Lower pulley cover. 104...Pulley, 106...Rope-shaped member. 110...head, 112...substrate, 114...
...Tube body, 112a...Pulley, 116...
Pulley cover, 118...Belt, 120...
Main axis, 146, 95.97, 89. ...Pulley, 1
50,106...Rope-shaped member.

Claims (1)

[Claims] 1. A base shaft 38 fixed to a base 34 that can be fixed to a drawing board.
a fixed pulley 40 fixed to the base shaft 38; a first arm 44 having one end rotatably connected to the base shaft 38 and the other end rotatably connected to the center shaft 92; An intermediate pulley 94 having a 1# (IF) pulley portion fixed to the intermediate shaft 92, one end rotatably connected to the intermediate shaft 92, and the other portion rotatably connected to the tube body 114 of the head 110. A second arm 100 to be connected, a head pulley 1"12a fixed to the tube body 100, and the head pulley 11
an endless belt 118 that is passed between the middle pulley 94 and the intermediate pulley 1 94; an endless belt 96 that is passed between the intermediate pulley 94 and the fixed pulley 40; The handle 124 is fixed to the upper end, and the scale mounting plate 1 is fixed to the lower end.
In the arm type flexible parallel ruler consisting of a main shaft 1i'0 to which 26 is fixed, the tube body 114 of the head 110
A first boot I is rotatably mounted on the side around the tube body 114.
J 146, and a second pulley 9 is mounted on the intermediate shaft 92.
7 and a third pulley 95 having the same diameter as the first pulley 146
are rotatably attached so as to interlock with each other, and the base shaft 38
A fourth pulley 89 with the same diameter as the second pulley 9 An endless rope-like member 150, 106 is passed between them with an appropriate tension,
One end of the spring 148 is engaged with the first pulley 146, and the other end of the spring 148 is engaged with a member 144 that rotates in rotation with the main shaft 120. A scale balancer characterized in that a balancing rotational torque is applied in a direction that offsets the rotational torque due to the weight of the scale attached to the scale mounting plate 126 by elasticity.