JPS63112200A - Scale balancer in universal parallel ruler - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a scale balance device for balancing the rotational force due to the weight of a scale in a universal parallel ruler.

Conventional technology Conventional devices include Japanese Utility Model Publication No. 52-28605, Japanese Utility Model Application Publication No. 59-131893, and Japanese Patent Application Laid-open No. 1983-1.0.
A device described in Japanese Patent No. 4898 and the like is known.

In the device disclosed in Japanese Utility Model Publication No. 52-28605, a driven member is brought into contact with a cam member that rotates together with the scale as a braking device via spring elasticity, thereby balancing the rotational force due to the scale's own weight.

The device disclosed in Japanese Utility Model Application Publication No. 59-131893 balances the rotational force due to the weight of the scale by wrapping a lobe with tensile elasticity around a rotating member that rotates together with the scale.

The device disclosed in Japanese Patent Application Laid-open No. 104898/1980 links a rotating body whose axis is located at a different position from the rotating axis of the scale to the scale, and biases this rotating body with spring elasticity so that the weight of the scale is reduced. It balances the rotational force.

Problems to be Solved by the Invention In this type of scale balancing device, when the drawing board to which the universal parallel ruler is attached is tilted, the rotational force due to its own weight becomes zero when the scale faces directly above and directly below. Is it possible to provide a smooth balance that corresponds to the fact that the rotational force gradually increases as it rotates from directly above to the horizontal direction, reaches its maximum at the horizontal position, and gradually decreases as it rotates from the horizontal to directly below? The question becomes.

In the device of Utility Model Publication No. 52-28605, the cam member that rotates integrally with the scale is brought into contact with the driven member as a braking device via spring elasticity, so smooth braking is achieved.
Additionally, there is the problem that rotating the scale becomes difficult, so the device of Utility Model Application Publication No. 59-131893 wraps a lobe, which is biased by a tension spring, around a rotating member that rotates together with the scale. This is good when the scale rotates horizontally from directly above, but the pulling force continues to increase as it rotates from horizontally to downwards, making it difficult to balance the rotational force due to the scale's own weight. The device disclosed in Japanese Patent Application Laid-Open No. 61-104898 rotates a rotating body whose axis is located at a different position from the rotating axis of the scale in conjunction with the scale, and applies a spring elasticity to this rotating body to rotate the scale. Because it balances the rotational force due to its own weight, the device becomes complicated and there is a problem in that it places a burden on the interlocking device.

Means for Solving the Problems Accordingly, the present invention provides a winding pulley and a cam member on a rotating member of a scale operation head that rotates together with the scale, and a tension member is provided on the winding pulley so that it can wind. In addition, a driven member is provided on the cam member, and a balance rod is provided on the non-rotating member of the head portion so as to be swingable about a fulcrum shaft, and the other end side of the tension member and the other end side of the driven member are connected to the non-rotating member of the head portion. A scale balance device for a universal parallel ruler is provided, in which both sides of a balance rod are connected to each other with a fulcrum shaft in between, and tension spring elasticity is imparted to the tension member or driven member.

Action When the scale rotates horizontally from directly above, the tension member is retracted in accordance with the rotation of the take-up pulley, applying spring elasticity to the rotating member that is approximately proportional to the amount of retraction, counteracting the rotational force due to the scale's own weight. When the scale is balanced and rotates from horizontal to straight down, the amount of retraction of the tension member increases, but the cam member causes the driven member to move in the retraction direction beyond the amount of retraction of the tension member via the balance rod. Move and reduce the spring elasticity acting on the tension member (excessively) to balance against the rotation and three sides due to the scale's own weight.

EXAMPLES The apparatus of the present invention will be explained in detail with reference to the examples shown below. 1. A scale operation connected to a cursor that moves parallel to the drawing surface or a pulley stand. It constitutes a non-rotating member of the invention, and its bearing portion rotatably supports a hollow shaft rod 2. Axle rod 2
A rotating member 3 according to the present invention is integrally fixed to the upper part with screws, and a scale support base 4 is integrally fixed to the lower part with screws. A handle 5 for operating the scale is integrally fixed to the upper part of the rotating member 3, and a scale mounting plate 6 is fixed to the tip of the scale support base 4. It is configured so that the scale attached to it can be rotated. Further, a protractor plate 7 is rotatably attached to the bearing portion and can be fixed to the bearing base 1 at any time by a fixing lever 8, and is opposed to a vernier plate 9 fixed to the scale support base 4 side. The protractor board 7 also has a scale fixing plate 10 and an indexing plate 11 fixed integrally, and the scale fixing plate 10 can be fixed to the scale support base 4 at any time with a scale fixing lever (not shown), and the indexing Board 1
1 is configured such that indexing claws 12 are engaged with grooves at predetermined angles and can be fixed to the scale support base 4. Indexing claw 1
2 includes an interlocking piece 13 that interlocks along the lower surface of the scale support base 4, a lever 14 that penetrates the shaft rod 2 and the hollow part of the rotating member 3, and a lever 15 that is provided on the side of the handle 5. They are provided so that they can be connected to and removed from the index plate 11 in conjunction with each other. Reference numeral 16 and 17 designate a cover that rotates together with the scale mounting plate 6, and a magnifying glass 18 is provided at the portion facing the vernier plate 9. 19 is a scale mounting screw.

Here, the rotating member 3 according to the present invention is provided with a winding pulley 20 having a substantially arc shape, and a winding pulley 20 integrally provided with a cam member 21 having a downward groove shape. 20, one end side of a tension member 22 is attached so as to be retractable, and the other end side of the tension member 20 is attached to a tension spring 23.
It is attached to one side of the balance rod 24 so that its length can be adjusted freely. In the case of the embodiment, a hollow outer screw-shaped adjustment rod 26 is screwed into the balance rod 24 so as to be freely movable and retractable, and a tension rod 27 that can move forward and backward together with the adjustment rod 26 and is fitted in a freely rotatable manner is provided in the hollow portion. and the other end of the tension member 22 is attached. The balance rod 24 has its middle portion mounted on a fulcrum shaft 25 erected on the bearing base 1 so as to be swingable. balance rod 2
4, the other end side of the driven member 28 of the cam member 21 is swingably provided. In the case of the embodiment, a bearing 29 rotatably provided at the tip of the driven member 28 is engaged in the groove of the cam member 21, and the tension member 22 and the driven member 28 are engaged with each other.
and are balanced by the tensile force of the tension spring 23. 3
0 is a guide member that guides the driven member 28 so as to be swingable and movable in the longitudinal direction. Further, in the case of the embodiment, the tension member 22 is provided with a spring elastic member 31 that applies a tensile force in the direction of deflection. That is, the support shaft 3 erected on the bearing base 1
A lever 33 is provided which swings about 2, a tensile control roller 34 at the tip of the lever 33 is brought into rotatable contact with one side of the tension member 22, and the lever 33 is erected on the bearing base 1. It is configured to be pulled in the direction of deflection by a spring elastic member 31 stretched between it and the support shaft 35. Therefore, in this case, when the tensile force applied to the tensile member 22 is weak, the tensile member 22 is deflected by the tensile force of the spring elastic member 31, and when the tensile force becomes strong, the tensile member 22 becomes linear. The amount of movement of the tension member 22 in the winding direction can be adjusted by adjusting the strength of the tensile force applied to the tension member 22 by the winding pulley 2o.

As shown in FIGS. 5 to 7, the take-up pulley 20 and the cam member 21 rotate through 180 degrees as the scale (scale mounting plate 6) rotates from the top position to the horizontal position to the bottom position. Since it rotates, at least the configuration of this 180° portion is sufficient. In the case of the embodiment, first, the take-up pulley 2o has a semicircular shape of 180° along A-B-C in the figure, and the cam member 21 has a 90' portion between B and C in the figure. It has a four-arc shape, and the 90' portion between C and D has an oval shape in which the radius of rotation gradually increases. Therefore, in this case,
Figures 5 to 6, where the scale rotates horizontally from directly above.
When transitioning to the figure, the tension member 22 is connected to the winding pulley 20.
The scale is wound up along the circular arc of the scale, and receives the tensile force of the tension spring 23 and the spring elastic member 31 in proportion to the amount of winding-in, thereby offsetting the rotational force due to the scale's own weight and achieving balance. Further, at this time, since the radius of rotation of the cam member 21 is kept constant, the balance rod 24 is maintained in an immovable state. Next, when transitioning from FIG. 6 to FIG. 7, where the scale rotates from horizontal to directly below, the tension member 2
2 is further wound up by the circular arc from B to C of the take-up pulley 20, but at this time the cam member 21 is
Since the driven member 28 is moved from right to left in the figure along a shape in which the radius of rotation gradually increases from The tension force of the tension spring 23 is gradually weakened to balance the rotational force due to the scale's own weight. In this case, it is preferable that the position of the fulcrum shaft 25 of the balance rod 24 is adjusted such that the distance between the connecting portion with the tension member 22 is approximately three times or more greater than the distance between the connecting portion with the driven member 28. The fulcrum shaft 25 of this balance rod 24
In order to reduce the ratio of movement of the tension member 22 to the amount of movement of the driven member 28 due to the position adjustment, the shape of the winding pulley 20 is changed from B to C as shown by broken lines in FIGS. 5 to 7.
The radius of rotation is made extremely small in the part from B to C'', and the amount of winding of the tension member 22 is made small from the position where the scale is horizontal in Figure 6 to the position where the scale is facing straight down in Figure 7. It can be configured to: Further, with this configuration, the amount of increase in the radius of rotation between C and D of the cam member 21 can be reduced accordingly.

Effects As described above, according to the present invention, the scale operating head has the following effects:
A winding pulley and a cam member are provided on a rotating member that rotates together with the scale, a tension member is provided on the winding pulley so as to be able to wind the scale, and a driven member is provided on the cam member,
A balance rod is provided in the non-rotating member of the head portion so as to be swingable with a fulcrum shaft in the middle, and the other end side of the tension member and the other end side of the driven member are respectively placed on both sides of the balance rod with the fulcrum shaft in between. Since the scale is connected and has a structure in which a tension spring elasticity is applied to the tension member or the driven member, when the scale rotates horizontally from directly above, the tension member is drawn in according to the rotation of the take-up pulley, A spring elasticity approximately proportional to the amount of retraction is applied to the rotating member to balance the scale against the rotational force due to the scale's own weight, and when rotating from horizontal to straight down, the amount of retraction of the tension member increases, but The cam member moves the driven member via the balance rod in the retraction direction beyond the retraction amount of the tension member, gradually reducing the spring elasticity acting on the tension member, and counterbalancing the rotational force due to the weight of the scale. This has the effect of providing a scale balance device that operates reasonably smoothly without making any major design changes to the scale operation head of the conventional universal parallel ruler.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a main part of an embodiment of the device of the present invention, FIG. 2 is a cross-sectional view taken along the line AA' in FIG. 1, and FIG. FIG. 4 is a longitudinal sectional view taken along the line B-B', FIG. 4 is a longitudinal sectional front view showing the main part of FIG. 1, and FIGS. It is a schematic explanatory diagram for explaining. 1... Bearing base (non-rotating member) 2... Shaft rod 3... Rotating member 4... Scale support base 5... Handle 6... Scale mounting plate 20... Winding pulley 21... - Cam member 22 - Tension member 23 - Tension spring 24 - Balance rod 25 - Fulcrum shaft 28 - Followed member 31 - Spring elastic member 33 - Lever 34 - Tension roller

Claims (4)

[Claims] (1) A winding pulley and a cam member are provided on the rotating member that rotates together with the scale, a tension member is provided on the winding pulley to enable winding, a driven member is provided on the cam member, and a non-rotating member is A balance rod is provided swingably with a fulcrum shaft in the middle, and the other end side of the tension member and the other end side of the driven member are respectively connected to both sides of the balance rod with the fulcrum shaft in between,
A scale balance device for a universal parallel ruler in which a tension spring elasticity is imparted to the tension member or driven member. (2) In the device according to claim (1), a scale balance device for a universal parallel ruler, wherein the shape of the pulley and the cam member is formed to correspond to the rotational force due to the scale's own weight due to the rotation angle of the scale. (3) In the device according to claim (1) or (2), a scale balance device for a universal parallel ruler in which a tension spring elasticity is imparted to the tension member. (4) In the device according to claim (1), (2), or (3), a scale balance device for a universal parallel ruler in which the relative position of the fulcrum shaft and the balance rod is movable.