JPH0420635Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic guide device for a balance weight such as a rail type universal parallel ruler used for a tiltable drawing board.

Rail-type flexible parallel rulers, parallel rulers, coordinate analyzers, etc. are usually installed on a tiltable drawing board.

In this type of device, a magnetic guide device uses the magnetic force of a magnet to bias the balance weight, which is freely movable within the weight insertion space of the vertical rail, upwardly, thereby reducing the movement of the balance weight. is publicly known. When the vertical movement of the vertical rail of the balance weight in the weight insertion space in the direction perpendicular to the drawing board is restricted by rollers, when the balance weight travels in the weight insertion space, the balance weight does not insert the weight. A movement allowance is provided to eliminate the collision of the upper and lower walls of the space and generate collision noise, and to allow the balance weight to move vertically within the weight insertion space in response to changes in magnetic force. There is no need to set a range, and the vertical width of the weight insertion space can be reduced, resulting in effects such as the ability to reduce the thickness of the vertical rail.

However, in a configuration where the vertical movement of the balance weight is restricted, if you try to make the balance weight move lightly and smoothly along the rail by applying a magnetic force that biases the balance weight upward, the following problem occurs. The problem arises.

When the drawing board is changed from its minimum possible inclination angle, for example, from a horizontal state to a maximum possible inclination angle of, for example, 90 degrees with respect to the floor surface, the diagram according to the total weight W of the balance weights is shown in Fig. 4. Against the board surface,
The component force S in the downward vertical direction is WCosθ, where θ is the angle of the drawing board.

If the same magnetic upward biasing force as this component force S is applied to the balance weight in the opposite direction to the direction of the component force S, the distance between the balance weight and the bottom of the weight insertion space that supports it becomes zero. pressure, that is, can be set to a balanced state. If no magnetic force adjustment mechanism is provided, the balance state can be set only at one tilt angle within the tiltable range of the drawing board. Therefore, when the drawing board is changed from its balance angle, the above-mentioned balance state is disrupted and pressure is generated between the vertical movement regulating roller of the balance weight and the roller receiving wall surface of the weight insertion space, and this pressure acts as a load on the movement of the vertical cursor connected to the balance weight.

Therefore, the present invention aims to reduce the distance between the vertical movement regulating roller of the balance weight and the roller receiving surface when the drawing board is set at a desired angle between the minimum possible inclination angle and the maximum possible inclination angle. The purpose is to minimize the maximum pressure generated on the rail and to facilitate smooth movement of the balance weight along the rail.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be explained in detail below based on an embodiment of a rail-type flexible parallel ruler shown in the accompanying drawings.

Reference numeral 2 denotes a drafting table that supports the drawing board 4, and is designed so that the inclination angle of the drawing board 4 can be adjusted within the range of 0 degrees (minimum possible inclination angle) to 90 degrees (maximum possible inclination angle) with respect to the floor surface. It is composed of Reference numeral 6 denotes a horizontal rail fixed to the upper edge of the drawing board 4, to which a horizontal cursor is movably connected. A vertical rail 8 has one end connected to the horizontal cursor, and a tail roller 10 is rotatably attached to the other end of the rail. A weight insertion space 8a for a balance weight 12 is formed in the vertical rail 8 over its entire length in the longitudinal direction, and a balance weight 12 having an appropriate weight is movably disposed within the space 8a. There is. The vertical rail 8 has rollers 14
A vertical cursor 16 is movably connected to the head 18 via a hinge member.
are connected. A straight edge 2 is attached to the head 18.
0,22 are attached. Vertical cursor 1
6 and the balance weight 12 are connected by a wire rope 24, and the wire rope 24 is stretched over rope pulleys (not shown) rotatably disposed at both ends of the vertical rail 8. The balance weight 12 is connected to the vertical cursor 16.
When the vertical cursor 16 is moved along the vertical rail 8, the vertical cursor 16 is moved along the space 8a in a direction opposite to the moving direction of the vertical cursor 16. When the drawing board 4 is tilted in the upright direction, the force that causes the vertical cursor 16 to move in the falling direction along the vertical rail 8 due to the weight of the head 18 is due to the weight of the balance weight 12. As a result, even if the head 18 is released while the drawing board 4 is tilted, the head 18 will not fall along the drawing board 4 and will reach the desired position on the drawing board 4. Stay stable in position.

In FIG. 2, 26 and 28 are elongated plate-shaped magnets arranged along the entire length on both sides of the bottom of the space 8a, and in this embodiment, commercially available manganese aluminum magnets are used. There is. 30 and 32 are long plate-shaped magnets arranged on the balance weight 12, and these magnets are similar to the magnets 26 and 28.
The homopolar planes are facing each other. The magnets 26, 30
The balance weight 12 is biased upward perpendicularly to the four surfaces of the drawing board by the repulsive magnetic force between the space 28 and 32. 34 is balance weight 12
A downward regulating roller is rotatably supported by four notches 36 formed in the roller 3.
4 is in rotatable contact with the bottom wall surface of the weight insertion space 8a. Reference numeral 38 denotes upward regulating rollers rotatably supported by the notches 36, respectively;
The roller 38 rotatably contacts the upper wall surface of the weight insertion space 8a. As shown in FIG. 4, when the drawing board is tilted at an angle of .theta. with respect to the floor surface, the vertical rail 8 is tilted at an angle of .theta. with respect to the floor surface. Let W be the total weight of the balance weights 12, and the total weight W of the balance weights 12 causes the space 8a of the vertical rail 8 to be
Letting S be the component force of the balance weight 12 applied vertically downward to the bottom wall surface of , S = W cos θ.
When the inclination angle θ of the drawing board 4 is the minimum inclination angle of zero, the weight of the balance weight 12 is applied to the bottom wall surface of the space 8a via the downward regulating roller 34 in a downward direction with respect to the drawing board 4 surface. Assuming that the component force applied in the vertical direction is S ₂ and the component force S ₁ is the component force when the drawing board 4 has a maximum inclination angle of 90 degrees, as shown in FIG. 5, the magnet 2
The total repulsive magnetic force between 6 and 30 and between 28 and 32 is
If the balance weight 12 is set to the average value F of the values of S ₂ and S ₁ above and the balance weight 12 is biased upward perpendicularly to the surface of the drawing board 4, the drawing board 4 can be moved from the above zero.
Even if it is tilted arbitrarily within the tiltable range of 90 degrees, a load greater than the above F will not be applied to the bottom wall surface of the space 8a in the direction perpendicular to the 4 planes of the drawing board, and the predetermined drawing board inclination will not be applied. At this angle, the load on the bottom wall surface of the space 8a is zero, ie, a balanced state.

However, if the magnitude of the repulsive magnetic force between the magnets 26, 28 and 30, 32 is made larger or smaller than the value of F, in either case, when the drawing board 4 is set to the minimum or maximum inclination angle. ,
The pressure from the rollers 34 or 38 on the bottom wall surface or the top wall surface of the space 12a ends up being greater than the above value of F. The above value of F is the above component force because cos θ is 1 when the drawing board inclination angle θ is zero.
When S2 is W and the drawing board inclination angle θ is 90 degrees, cos θ is 0, so the component force S1 is zero, and the average value F of the component forces S2 and S1 is W/2.
That is, the average value F of the component forces S1 and S2 can be found as follows: F=(S2-S1)/2+S1. When the drawing board 4 changes from the minimum inclination angle of zero to the maximum inclination angle θx degrees (for example, 70 degrees), the above F is as clear from FIG. 6, since S2=Wcos0=WS2=Wcosθx ( W−Wcosθx)/2+Wcosθx. or,
When the drawing board 4 changes from the minimum inclination angle θx1 degree to the maximum inclination angle θx2 degrees, the above F can be determined as S2=Wcosθx1 S1=Wcosθx2, so F=WCosθX1−WCosθX2/2+WCosθX2.

Next, the operation of this embodiment will be explained.

When the minimum inclination angle of the drawing board 4 is set to zero, the component force of the total weight W of the balance weight 12 in the direction perpendicular to the drawing board 4 is W, and the magnets 26, 28 and 3
Since the repulsive magnetic force F in the upward direction perpendicular to the 4th surface of the drawing board between 0 and 32 is W/2, the load applied to the bottom wall surface of the space 8a is W-W/2=W/2.

Also, if you set drawing board 4 to a maximum inclination angle of 90 degrees,
The component force of the total weight W of the balance weight 12a in the direction perpendicular to the four faces of the drawing board is zero, and the magnets 26,
Since the repulsive magnetic force between 28 and 30, 32 is W/2, the upper wall surface of the space 12a has a magnetic force W/ A pressure of 2 is applied. however,
Due to the weight of the balance weight 12a and the magnetic force of the magnet,
No pressure exceeding W/2 is applied. if,
If the repulsion magnetic force is set to a value other than W/2, for example W/3, when the drawing board is at zero degrees, the difference between the weight of the balance weight and the magnetic force, that is, W-, will appear on the bottom wall of the space 8a. A pressure of W/3=2W/3 is applied, which is greater than the above W/2.

In the above configuration, when the head 18 is held in the hand and moved in a direction parallel to the vertical rail 8, the vertical cursor 16 moves along the vertical rail 8 in conjunction with the head 18, and the balance weight 12
moves along the weight insertion space 8a in the opposite direction to the vertical cursor 16. In this embodiment, the balance weight 12 is biased upward by magnetic repulsion, but it may be biased by magnetic attraction.

As mentioned above, the present invention has a balance weight 12
Since the vertical movement of the vertical rail is restricted within the weight insertion space, it is possible to prevent collision noise from occurring between the balance weight and the bottom wall surface and the top wall surface of the weight insertion space. When the plate is tilted at any angle within its tiltable range, the maximum pressure applied to the wall of the weight insertion space can be set to the minimum by the weight of the balance weight and the magnetic force. It has the advantage of being able to move lightly and smoothly along the rail.

[Brief explanation of the drawing]

The figures show preferred embodiments of the present invention, in which Fig. 1 is a front view, Fig. 2 is a sectional view, Fig. 3 is a plan view of the balance weight, Fig. 4 is an explanatory drawing, Fig. 5 is an explanatory drawing,
FIG. 6 is an explanatory diagram, and FIG. 7 is an explanatory diagram. 2...Drawing table, 4...Drawing board, 6...Horizontal rail,
8... Vertical rail, 10... Tail roller, 12... Balance weight, 12a... Weight insertion space, 14... Roller, 16... Vertical cursor, 18...
... Head, 20, 22 ... Straight ruler, 24 ... Wire rope, 26, 28 ... Magnet, 30, 32 ...
Magnet, 36...Notch, 34...Downward regulating roller, 38...Upward regulating roller.

Claims (1)

[Claims for Utility Model Registration] A vertical rail attached to a drawing board that can be tilted between the minimum possible inclination angle θX1 and the maximum possible inclination angle θX2 with respect to the floor surface, and vertical movement perpendicular to the drawing surface. a balance weight disposed in a weight insertion space formed along the longitudinal direction of the rail so as to be movable along the rail; and a balance weight attached to the vertical rail so as to be movable along the rail; and a vertical cursor connected to the balance weight by a rope or the like so as to move in opposite directions, and a vertical cursor provided opposite to each other on the wall side of the weight insertion space and on the balance weight side, and acting between the vertical cursor and the balance weight. In a device comprising a magnet that uses magnetic force to bias the balance weight upward and perpendicular to the drawing surface, when the total weight of the balance weight is W, the magnitude of the magnetic force between the magnets is: A balance weight magnetic guide device for a rail type flexible parallel ruler, etc., characterized in that the setting is WCosθX1−WCosθX2/2+WCosθX2.