JPH0473398B2 - - Google Patents

Description

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

[Conventional technology]

Various types of devices of this type have been developed in the past. JP-A-56-42696 discloses a scale balance device using magnetic force. Japanese Utility Model Application Publication No. 47-9478 discloses a scale balance device using balance weights. Japanese Utility Model Publication No. 52-28606 discloses a scale balance device using an eccentric cam and a roller that comes into elastic contact with the eccentric cam by a spring force. Special Public Service 1978-
No. 4640 and Japanese Patent Publication No. 57-47040 disclose a scale balance device using a balance weight movably disposed on a vertical rail.

[Problem that the invention seeks to solve]

The above device using magnetic force has a drawback that the structure becomes complicated. Devices using the above-mentioned balance weights have a drawback in that the weight of the head becomes large and the movement of the head becomes heavy. The device using the eccentric cam and spring described above has a defect in that the rotation of the scale becomes heavy. The device using the above-mentioned balance weight in a vertical rail has a defect that the movement range of the head is shortened because the movement range of the head along the vertical rail is restricted by the movement range of the balance weight along the vertical rail. did. An object of the present invention is to provide a scale balance device that eliminates the above-mentioned defects.

[Means to solve problems]

In order to achieve the above object, the present invention provides a universal parallel ruler in which a scale mounting plate 36 is rotatably supported on a base 16 supported so as to be movable in parallel along the drawing board 2. This is characterized in that the center of gravity of the scale mounting plate 36 and the center of gravity of the scale mounting plate 36 are made to substantially coincide with each other.

[Effect]

In the above configuration, when the drawing plate 2 is tilted and the scale mounting plate 36 is released from the scale mounting plate 36 to be freely rotatable, the scale mounting plate 36 is moved by its own weight to the base 1 However, since the center of gravity on the scale mounting plate 36 side and the center of rotation of the scale mounting plate 36 coincide, the scale mounting plate 3
6 is balanced and does not rotate relative to the base 16 and remains stationary.

〔Example〕

The configuration of the present invention will be explained below with reference to the accompanying drawings.

In FIG. 3, reference numeral 2 denotes a drawing board, which is supported on a drawing table which can be tilted so as to be fixed at a desired angle of inclination. Reference numeral 4 denotes a horizontal rail fixed to the upper side of the drawing board 2, to which a horizontal cursor 6 is movably attached, and one end of a vertical rail 8 is connected to the horizontal cursor 6. An arm is fixed to the other end of the vertical rail 8, and a tail roller 10 is rotatably supported on the arm. A vertical cursor 12 is movably attached to the vertical rail 8, a connecting plate 14 is rotatably supported on the rising portion of the vertical cursor 12, and a base 16 is rotatably supported on the connecting plate 14. ing. The vertical cursor 12 is connected to a balance weight movably disposed on the vertical rail 8 via a rope, so that the base 16 can be stopped at any position on the inclined drawing board 2. It is composed of A guide groove 20 is formed in an arc shape on the lower surface side of the base body 16. A guide concave curved surface 2 is provided on one end side of the base body 16 in an arc shape along the guide groove 20.
0a is formed. 22 is a guide plate;
The convex curved surface 22a formed thereon is in slidable contact with the guide concave curved surface 20a. The guide plate 22 has two rollers 24 and 26 whose outer diameter is slightly smaller than the width between the guide surfaces on both sides of the guide groove 20.
are rotatably supported, and the surfaces of the rollers 24 and 26 are in rotatable contact with the guide surface of the guide groove 20. A shaft body 28 is fixed to the guide plate 22, and the shaft body 28 is slidably inserted into an arcuate hole 30 formed in the base body 16 along the guide groove 20. A female threaded portion of a baseline lever 32 is screwed into a threaded portion formed on the upper portion of the shaft body 28 . An arcuate guide groove 34 is bored on the lower surface side of the guide plate 22. As shown in FIG. A guide concave curved surface 22b is formed in an arc shape along the guide groove 34 at one end of the guide plate 22. 36 is a scale mounting plate, and a convex curved surface 36a formed on this plate is in slidable contact with the guide concave curved surface 22b. The scale mounting plate 36
, two rollers 38 and 40 having an outer diameter slightly smaller than the width between the guide surfaces on both sides of the guide groove 34 of the guide plate 22 are rotatably supported.
The surface of 40 is in rotatable contact with the guide surface of the guide groove 34. A shaft body 42 is fixed to the scale mounting plate 36, and the shaft body 42 is slidably inserted into an arcuate hole 44 formed through the guide plate 22 along the guide groove 34. There is. A female threaded portion of an angle lever 46 is screwed into a threaded portion formed on the upper portion of the shaft body 42 . 48 is a handle fixed to the scale mounting plate 36;
Reference numerals 50 and 52 indicate scales that are detachably fixed to the scale mounting plate 36. The center of gravity G1 of the scale mounting plate 36 is set at a position that coincides with the center of rotation of the scale mounting plate 36 relative to the guide plate 22, that is, the center of the circular line 54 passing through the guide groove 34. In addition, the center of gravity G2 of the scale mounting plate 36 in the state where the guide plate 22 is connected coincides with the center of rotation of the guide plate 22 with respect to the base 16, that is, the center of the circular line 56 passing through the guide groove 20. set in position. 58 is an angle scale, 60 is an angle index, 62 is a base line scale, and 64 is a base line index.

Next, the operation of this embodiment will be explained.

The guide plate 22 is fixed to the base body 16 by screwing the baseline lever 32 to the shaft body 28 in advance, and with the base body 16 stationary on the inclined drawing board 2,
When the angle lever 46 is loosened, the scale mounting plate 36 becomes rotatable along the guide concave curved surface 22b of the guide plate 22 and the guide groove 34. However, since the center of gravity of the scale mounting plate 36 and its center of rotation coincide, the scale mounting plate 3
6 is balanced, and even if the handle 48 is released, the scale mounting plate 36 remains stationary without rapidly rotating in the falling direction. When performing so-called baseline adjustment by rotating the scale mounting plate 36 while keeping the angle of the scale 50 aligned with the zero degrees of the angle scale 58, align the index 60 with the zero degrees of the angle scale 58 and turn the angle lever 46. The scale mounting plate 36 is fixed to the guide plate 22 by rotating in the tightening direction. Next, when the baseline lever 32 is loosened, the guide plate 22 to which the scale attachment plate 36 is fixed becomes rotatable along the guide concave curved surface 20a of the base body 16 and the guide groove 20. However, the scale mounting plate 3 including the guide plate 22
Since the center of gravity on the 6 side and its center of rotation with respect to the base body 16 coincide, the scale mounting plate 36 side is balanced, and even if you take your hand off the handle 48,
The scale attachment plate 36 maintains a stationary state without rapidly rotating in the falling direction. In the balanced state, rotate the handle 48 by hand to rotate the guide plate 22 along the guide concave curved surface 20a of the base body 16, and set the scale 50 at a desired angle.
After that, the base line lever 32 is operated to fix the guide plate 22 to the base body 16. In addition, when implementing the present invention, the center of gravity G1 on the scale mounting plate 36 side,
G2 and guide plate 2 of scale mounting plate 36
2. Theoretically, the centers of rotation with respect to the base 16 should coincide. However, when the scale mounting plate 36 is free with respect to the guide plate 22,
Alternatively, when the guide plate 22 is free with respect to the base 16, rotational moment due to the weight of the scale mounting plate 36 is applied to the rollers 38, 40, 24, and 26, so the friction between the rollers and their guide surfaces is reduced. The force is large, and due to this frictional force,
Even if the center of gravity and the center of rotation do not exactly match, the scale attachment 36 is balanced. Further, the mechanism for rotatably supporting the scale attachment plate 36 side, that is, the parallel moving body side, is not particularly limited to the structure shown in the embodiment.

Further, the number of arcuate holes 30, 44 is not limited to two in particular, and a plurality may be used.

〔effect〕

As described above, the present invention uses the center of gravity on the scale mounting plate to balance the scale, which simplifies the structure and allows the scale to be rotated lightly and smoothly by hand. This has the effect of achieving the purpose stated at the beginning.

[Brief explanation of the drawing]

The drawings show a preferred embodiment of the present invention, with FIG. 1 being a plan view, FIG. 2 being a sectional view, and FIG. 3 being an overall front view. 2...Drawing board, 4...Horizontal rail, 6...Horizontal cursor, 8...Vertical rail, 12...Vertical cursor, 14
... Connection plate, 16 ... Base, 20, 34 ... Guide groove, 22 ... Guide plate, 24, 26, 38, 40
...Colo, 28, 42...Shaft body, 32, 46...
Lever, 36...Scale mounting plate, 48...Handle, 50, 52...Scale.

Claims (1)

[Claims] 1. In a universal parallel ruler in which a scale mounting plate 36 is rotatably supported on a base 16 that is supported so as to be able to move in parallel along the drawing board 2, the center of rotation of the scale mounting plate 36 and the center of gravity on the scale mounting plate 36 side are A scale balance device characterized by substantially matching the scales.