JPS6052398A - 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 The present invention provides a universal parallel ruler in which when the scale is freely rotated relative to 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 for maintaining a stable stationary state without rotating.

In FIG. 4, a spring 6 that can reach the non-rotating member side of the head is attached to the rotating body 4 to which the scale 2 is connected, and the tensile force of the spring 6 is applied to the eccentric part of the rotating body 4. In a scale balance device that cancels out the rotational torque of the rotating body 4 due to the weight of the scale 2, when the scale 2 is at approximately +90 degrees, the tensile force of the spring 6 is zero.

The rotation 1-lux of the rotating body 4 about the multiple axis 8 due to the weight of the scale 2 is set to zero. In the above configuration, when the rotating body 4 is rotated so that '<scale 2 is zero degrees as shown in FIG. 4(b), the tensile load of the spring is, for example, 5 kg.
Suppose that it acts on the rotating body 4. At this time, the rotational torque of the rotating body 4 due to the spring 6 becomes maximum. Furthermore, when the rotating body 4 is rotated in the direction of rotation of the hour hand until the scale 2 reaches -90 degrees (see Fig. 4C), the spring force becomes 10 kg, and the rotation 1-lux due to the spring force of the rotating body 4 becomes zero. . In this case, a spring force of 10 kg is applied between the rotating body 4 and the multiple shaft 8.
loads are applied. This increases the pressure load of the rotary body 4 on the multiple shaft 8, which adversely affects the durability of the head and the angular accuracy of constant m2. However, as shown in FIGS. 4 d to 4 f, a gear 8 is rotatably supported on a non-rotating member of the head with a shaft 1-0, and the gear 8 and the teeth provided on the outer periphery of each of the rotating bodies 4 are meshed with each other. In the configuration in which the spring 6 is attached to the eccentric part of each gear 8, when the scale 2 is +90 degrees, the spring force is zero, and if the 1-luke of the gear 8 is set to zero, when the scale 2 is 0 degrees, the spring force is zero. The spring force is 5 kg, and the 1-lux of gear 8 is maximum. When the gear 8 is rotated until the scale 2 reaches 190 degrees as shown in FIG. 4f, the spring force becomes 10 kg, but the rotational torque of the gear 8 due to the spring force is zero. In this case, since only the rotating body torque of the gear 8 acts on the rotating body 4, the pressure load due to the spring 6 acting between the rotating body 4 and the multiple shaft 8 is zero. As is clear from the above explanation, the rotating body to which the scales are connected is
By engaging with a gear provided on a non-rotating member of the head and applying a spring force to the gear, the pressure load due to the spring force between the rotating body and the multiple shafts can be reduced. However, if the diameter of the gear of the rotating body 4 is small, the force F acting on the rotating body 4 in the balancing direction must be increased.

When the above-mentioned F becomes large, the frictional force with the rotating body 4 becomes large due to this F. In order to reduce the above F, it is necessary to make the diameter of the rotating body 4 as large as possible. However, since the gear 8 must rotate at the same time as the rotating body 4, the larger the diameter of the rotating body 4 is, the larger the diameter of the gear 8 must be, and the storage space for the gear 8 becomes larger. .

The purpose of the present invention is to provide a scale balance device that solves the above problems, and by interposing two intermediate gears between the rotating body 4 and the gear 8, the diameter of the gear can be increased. This makes it possible to increase the diameter of the rotating body without having to do so.

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

In FIG. 1, reference numeral 10 denotes a drawing board, which is fixed to a support stopper of a tiltable drafting table so that it can be fixed at a desired angle of inclination between horizontal and vertical. 12 is a horizontal rail arranged on the upper side of the drawing board 10, and a horizontal cursor 14 is movably attached to this rail. The upper end of a vertical rail 16 is connected to the horizontal cursor 14. The lower end of the vertical rail 16 is placed movably on the illustration 10 via a tail roller.

A vertical cursor 18 is movably attached to the vertical rail 16, and a support substrate 24 of the head 22 is connected to this via a known double hinge mechanism 20. In FIG. 2, reference numeral 26 denotes a tubular double shaft rotatably supported by the support substrate 24, and a tubular spacer 28 and a protractor 30 are fixed to the flange of the double shaft 26 with screws. The protractor board 30 is releasably fixed to the support substrate 24 by a base plate 1r (not shown). 32 is a main shaft, and its outer peripheral surface is rotatably fitted to the inner peripheral surface of the compound shaft 26. A handle 34 is fixed to the upper part of the main shaft 32, and a spacer 3 is fixed to the lower part of the main shaft 32.
A scale mounting plate 38 is fixed via 6. Scales 40 and 42 are fixed to the scale mounting plate 38. A first gear 44 is formed on the scale mounting plate 38 over a range of approximately 240 degrees around the rotation center of the main shaft 32. Reference numeral 46 denotes a second gear, and the gear 42 is connected to a disk 50 that is rotatably supported by a shaft 48 on the support substrate 24. A space for arranging a rope 52 is formed over a predetermined range between the disk 50 and the gear 46. The bracket formed on the gear 46 has a diameter direction 4 of the gear 46. −． A four-way screw shaft 54 is installed, and a molding 56 is screwed onto the screw shaft 54.

A bridge member 58 is rotatably fitted into the recessed portion of the molding 56. The bridge member 58 is connected to the threaded shaft 5 of the gear 46.
4, and is configured to move in conjunction with the movement of the molding 56 along the screw shaft 54. A metal terminal 52a connected to one end of the rope 52 is fitted into the bridge member 58. 60 is the support substrate 2
4 is a guide pulley rotatably supported by a shaft, and the rope 52 is hung on this guide pulley. The other end of the rope 52 is connected to one end of a spring 62.

The other end of the spring 62 is engaged with a screw fixed to the support substrate 24. Reference numeral 64 denotes a shaft fixed to the support substrate 24, and an intermediate gear 66 consisting of a two-stage gear is rotatably supported on this. Small diameter gear 6 of the intermediate gear 66
6a meshes with the second gear 46, and the large diameter gear meshes with the first gear 44.

In this embodiment, the diameter of the first gear 44 is A, and the large diameter gear 66 is
The diameter of t+ is set to B, the diameter of the second gear 46 is C1, and the diameter of the small diameter gear 66a is set to D, so that A:B=C:D.

Next, the operation of this embodiment will be explained.

When the scale mounting plate 38 is released from being fixed to the support substrates 2 and 4 and the scale mounting plate 38 is in a free rotation state,
When the drawing plate 10 is tilted, the scale mounting plate 38 is moved around the multiple shaft 26 due to the weight of the scales 40, 42, etc.

In FIG. 3, rotations 1 to lux E occur in the counterclockwise direction of rotation of the hour hand in a plane parallel to the surface of the drawing board 10.

On the other hand, due to the tensile elasticity of the spring 62, a rotational torque F is generated in the second gear 46 in the direction of rotation of the 1 hour hand in FIG.
is transmitted as torque in the direction of rotation of the hour hand. The rotational torque due to the weight of the scale 40, 42, etc. of the first gear 44 and the rotational torque due to the spring 62 are in opposite directions, so they cancel each other out.
Due to the weight, such as 0.42 mm, it does not suddenly rotate with respect to the support substrate 24 and maintains a stationary and stable state.

As mentioned above, the diameter A of the first gear 44 and the large diameter gear GG
Since the ratio A:B of the diameter B of b is the same as the ratio C:D of the diameter C of the second gear 46 and the diameter of the small diameter gear 66a, the rotational angular displacement of the first gear 44 and the second The rotational angular displacement of the gear 46 is the same, and is determined by the sine curve of the rotational torque due to the weight of the scale 40, 4.2, etc. of the first gear 44 as the first gear 44 rotates, and the spring 62. The sine curve of the rotational torque accompanying the rotation of the second gear 46 is synchronized.

If the second gear 66 is not provided and the spring 46 of the second gear is
[Rotation due to] - To synchronize the sine curve of the torque with the sine curve of the rotational torque of the first gear 44 due to the weight of the scale 4' 0.42, etc., the diameter of the second gear 4G should be It must be the same as the diameter of the

In this case, if the diameter of the first gear 44 is increased, the diameter of the second gear 4G must also be increased accordingly. If the diameter of the first gear 44 is made small, the radius required for one torque of rotation of the gear 4/I becomes smaller, so it is necessary to increase the one torque of rotation for balance of the gear meshing with the first gear 44. As shown in FIG. 3, the balancing force F acting on the first gear 44 acts as a reaction force G on the gear 44, and this reaction force G and the force 1-1 due to the weight of the scale mounting plate 38, etc. The force acts as a resultant force J between the compound shaft 26 and the main shaft 32. This resultant force J is the IP between the main shaft 32 and the double shaft 26,
Acts as a vibrational force. In order to reduce the above resultant force J, the first
The diameter of the gear 44 must be increased. gear 4
If the diameter of the gear 4 is large, the rotational torque of the gear 44 due to the balance force F acting on the gear 44 can be increased.

Therefore, with a small balance force F, it is possible to generate a rotational torque in the first gear 44 that balances the rotational torque of the first gear 44 due to the weight of the scale 40, 42, etc.

The tensile force of the spring 46 is Fl, and the radius of the first gear 44 is R1.
, the radius of the second gear 46 is R2, RIXF=R2XFI Since R2<R1, F<Fl.

That is, the spring 46 becomes a strong spring, and the amount of displacement thereof is reduced, so that the durability of the spring 46 is improved.

Note that the value of the load W applied to the center of gravity position on the scale mounting plate 28 side due to the weight of the scale 30, 32, etc. changes as the inclination angle of the illustration 10 changes.

Therefore, when the inclination angle of the drawing board 10 is changed, the gear 4 of the rope 52 can be adjusted by rotating the molding 56.
The amount of eccentricity with respect to G is adjusted, and the magnitude of the rotation of the second gear 46 in the balance direction from 1 to 1 torque is adjusted.

Since the present invention has been constructed as described above, it has the effect of being able to achieve the object stated at the beginning.

[Brief explanation of drawings]

1 is a plan view, FIG. 2 is a sectional view, FIG. 3 is a bottom view, and FIG. 4 is an explanatory view. 2...Scale, 4...Rotating body, 6...Spring. 10...Drawing board, 12...Horizontal rail, 14...
・Horizontal cursor, 16... Vertical rail, 18... Vertical cursor, 22... Head, 24... Support board, 26... Multi-axis, 28... Spacer, 30・
...Protractor, 32...Main shaft, 34...Handle, 36...Spacer, 38...Scale mounting plate, 40.42...Scale, 44...・First
gear, 46... second gear, 50...'... board, 5
2...Rope, 54...Screw shaft, 56°°・°
Molding, 58... Bridge member, 60... Guide pulley, 62... Spring, 64... Shaft body. 66...2-stage intermediate gear! 4! i Applicant Muto Kogyo Co., Ltd. Representative Patent Attorney M. Nishijima (0) (b) (C) Figure 4 (d) (e) (f)

Claims (1)

[Claims] 1. A head 22, a main shaft 32 rotatably supported on the non-rotating member side of the head 22, a scale mounting plate 38 fixed to the lower part of the main shaft 32, and a handle fixed to the upper part of the main shaft 32. 34 and scales 40 and 42 attached to the scale mounting plate 38, the ruler is integrally attached to the main shaft 32, and the center is set to the main shaft 3.
A first gear 44 is provided to coincide with the rotation center of the head 22, and a second gear 46 biased in a predetermined rotation direction and a second intermediate gear 66 are rotatably supported on the non-rotating member side of the head 22. The second gear 46 is rotated in such a manner that the rotational torque of the second gear 46 is transmitted to the first gear 44 in a direction that cancels out the rotational torque due to the weight of the scale 40, 42, etc. The small diameter gear 66a of the intermediate gear 66 is meshed with the large diameter gear 66b of the intermediate gear 66, and the large diameter gear 66b of the intermediate gear 66 is meshed with the first gear 44. A scale balance device characterized in that the second gear 46 and the small diameter gear 66a have approximately the same diameter ratio.