JPH0723038B2 - Head-repelling device for universal parallel ruler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention springs a head so that when the head is raised with respect to the drawing board surface, the head does not suddenly drop even if the hand is released from the raised position. The present invention relates to a head repulsion device in a universal parallel ruler that is repulsed in a rising direction by a force.

[Conventional technology]

As shown in FIG. 1 and FIG. 2, the rail type universal parallel ruler is such that one end of each of a pair of links 4 and 6 is rotatably connected by pivots 8 and 10 to a rising piece 2a fixedly mounted on the vertical cursor 2. However, the other ends of the links 4 and 6 are connected to both ends of the link 12 by the pivots 14 and 16.
It is rotatably connected by. Substrate 18 of head 18
2. The rising portion 20a of FIG. 2 is rotatably connected to the pivot shaft 14, and the weight of the head 18 causes the rising portion 20a to swing in the clockwise direction in FIG. It is locked by a stopper shaft 22. The rising pieces 2a links 4, 6, 12 form a parallel link, and the parallel link causes the head 18 to be supported by the cursor 2 so as to be able to move substantially parallel to the surface of the drawing board within a predetermined range in the vertical direction. ing. Reference numeral 26 is a link rotatably supported on the rising piece 2a by the pivot 8 and one end of which is rotatably connected to the projection of the link 4 by a pivot 28. 30 is a slide block, to which a coil spring is attached
One end of the coil spring 32 is connected, and the other end of the coil spring 32 is connected to the other end of the link 26. The slide block 30 is an adjusting screw
By rotating 34, it is supported by the vertical cursor 2 via a guide mechanism so as to be movable in the left-right direction in the drawing.

In the structure described above, the tensile force of the coil spring 32 urges the link 26 in the counterclockwise direction about the shaft 8, and the urging force urges the head 18 in a direction to float from the surface of the drawing board 24. . When the drawing board 24 is horizontal, the rotating force in the clockwise direction about the shafts 8 and 10 of the links 4 and 6 due to the weight of the head 18 becomes the largest. Therefore, when the drawing board 24 is horizontal, the head
If you want to lift 18 by spring 32 force, adjust screw 34
Is rotated to move the slide block 30 to the right in FIG. 1 to increase the amount of deflection of the spring 32.
When tilting 24, link 4 due to the weight of head 18,
The clockwise rotation moment around the axes 8 and 10 of 6 becomes smaller. Therefore, in this case, the slide block 30 is moved leftward in FIG. 1 to reduce the amount of deflection of the spring 32.

A change characteristic graph of the spring force with respect to the amount of deflection of a general spring is a straight line as shown in FIG. When the deflection range of the spring is set to A when the drawing plate 24 is horizontal, the strength of the spring force when the head 18 is brought into close contact with the drawing plate 24 is c, and the head 18 is the maximum from the drawing plate 24. The strength of the spring force when levitating to the raised position is b. When the flexure range of the spring is set to B when the drawing plate 24 is set slightly horizontal,
The strength of the spring force when the head 18 is brought into close contact with the drawing board 24 is b, and the strength of the spring force when the head 18 is levitated from the drawing board 24 to the highest position is a. When the deflection range of the spring is set to C when it is set slightly perpendicular to the floor of the drawing board 24, the strength of the spring force when the head 18 is brought into close contact with the drawing board 24 is a, and the strength of the head 18 is The strength of the spring force is zero when the board is levitated from the drawing board 24 to the highest position.

When the deflection range of the spring is set to D when the drawing plate 24 is set perpendicularly to the floor surface, the spring force is zero when the head 18 is brought into close contact with the drawing plate 24, and the head 18 is The strength of the spring force when it is levitated from the drawing plate 24 to the highest position is zero.

Therefore, the ratio of the spring force when the head is raised (at the time of float) and when it is lowered (when it comes into close contact with the board) when the board is vertical is zero: zero when the board is vertical, zero:
When a, slightly horizontal, it is a: b, and when horizontal, it is b: c, which are different.

The up and down movement of the head is performed by the drafter holding it by hand, and in that case, the feeling of use of the head differs depending on whether the drawing board is vertical, slightly vertical, slightly horizontal, or horizontal. Will end up.

The invention of Japanese Patent Laid-Open No. 59-199298 solves this problem by changing the point of action of the spring on the link with respect to the center of rotation of the link in response to changes in the inclination angle of the drawing board. That is, the radius of the pushing position (force point) of the spring with respect to the link is changed.

[Problems to be solved by the invention]

By changing the point of action of the spring on the link with respect to the center of rotation of the link, the change characteristic of the spring force with respect to the deflection amount of the spring when the plate 24 is horizontal is shown by the straight line E1 (see FIG. 15). Straight line for spring force change characteristics when it is slightly horizontal
E2, the spring force change characteristic when the drawing board is slightly vertical can be set to E3. In the figure, f1, f2, and f3 are spring forces when the head is lowered, and J1, J2, and J3 are spring forces when the head is raised. In this case, since the ratio of the spring force when the head is raised and when it is lowered does not change much, the feeling of use of the head by the drafter is that the drawing board is horizontal, slightly horizontal, and slightly vertical. And is almost the same. However,
When the drawing board is vertical, the radius is zero, that is, the center of rotation of the link must be the force point of the spring.
15 It is structurally difficult to obtain the characteristics indicated by E4 in the figure, and when the board is vertical, a force is applied to the pivot of the link,
Even if the head can be floated, there is a defect that a large frictional force is applied to the movement of the head in the ascending / descending direction and the movement of the head in the ascending / descending direction becomes heavy. The present invention aims to eliminate the above defects.

[Means for solving problems]

In order to achieve the above object, the present invention provides a horizontal rail 40, a vertical rail 44 that is movably connectable to the horizontal rail 40 at a right angle, and a vertical cursor 2 that is movably attached to the vertical rail 44. , A link 26 pivotally supported by the vertical cursor 2 so as to be swingable in a vertical direction, and the link 26 on the swing end side of the link 26.
A head 18 that is linked so as to interlock with the swing of 26, a spring 32 that biases the link 26 in the ascending direction, and a spring 32 that has a fulcrum on the vertical cursor 2 side, and a spring force that adjusts the elastic force of the spring 32. In the apparatus including the adjusting means, the spring 32 is a spring having a change characteristic of a spring force with respect to a deflection amount, which has an nth-order approximate curve characteristic (n is an integer of 2 or more).

[Action]

In the above-mentioned configuration, the spring 32 for urging the head 18 in the upward direction adjusts its deflection amount according to the inclination angle of the drawing board 24, and when the deflection amount is set to a large value, according to the elevation of the head 18, The amount of change in the spring force with respect to the amount of deflection of the spring 18 becomes large, and when the amount of deflection of the spring 32 is set to be small, the rate of change in the amount of spring force with respect to the amount of deflection of the spring 32 corresponding to the elevation of the head 18 becomes small. This is because when the head is lowered, even if the spring force is adjusted according to the inclination angle of the drawing board 24,
The ratio of the spring force at the time of rising is almost unchanged by the inclination angle of the drawing board 24, and the drawing person can always operate the head 18 in the vertical direction with a constant feeling of use.

〔Example〕

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 9, reference numeral 24 is a drawing plate, which is supported by a support frame of a drafting table that can be tilted so that it can be fixed at a desired tilt angle between horizontal and vertical with respect to the floor surface. Reference numeral 40 denotes a horizontal rail disposed on the upper side of the drawing board 24, on which a horizontal cursor 42
Is movably attached. The horizontal cursor 42 is connected to the upper end of the vertical rail 4. The lower end of the vertical rail 44 is movably mounted on a guide rail fixed to the drawing board 24 via a tail roller. 2 is the vertical rail 44
A vertical cursor movably attached to the support substrate 20 of the head 18 via a known head lifting / lowering support device 46. Direct rulers 50 and 52 are detachably attached to the ruler mounting plate 48 of the head 18. The head lifting / lowering support device 46 is composed of links 4 and 6, and one side of the plate-like link 4 has a rising piece 2a fixed to the vertical cursor 2.
At both ends of the pivot shaft 8 fixed to the
It is rotatably supported via 6 in a plane perpendicular to the surface of the drawing board. One end of the link 6 is rotatably supported on the rising piece 2a by a shaft 10 in a plane perpendicular to the surface of the drawing board 24. The bearing portion of the pair of protrusions 20b, 20b formed on the rising portion of the support substrate 20 of the head 18 is mounted on the pivot shaft 14 rotatably supported on the other side of the link 4 via pivot bearings 58, 60. It is rotatably fitted. A bearing portion at an upper portion of a link 12 is rotatably fitted to the poppet shaft 14, and a lower portion of the link 12 and the other end portion of the link 6 are freely rotatable by a shaft 16 as shown in FIG. Connected to. The side surface of the rising portion 20a of the support substrate 20 is in contact with the stopper shaft 22 that is screwed into the screw hole of the link 12. Reference numeral 64 denotes a head rising direction regulating stopper that is screwed into a screw hole formed in the projecting portion 20b of the supporting substrate 20, and faces the side surface of the projecting piece 4a of the link 4. Reference numeral 66 denotes a pair of parallel guide pins (the other one is not shown) projecting below the rising portion 2a of the vertical cursor 2 in a direction horizontal to the surface of the drawing board 24 (see FIG. 6), The shaft hole of the slide block 30 is slidably fitted in these. As shown in FIG. 1, a screw hole is formed in the slide block 30, and a spring adjusting screw 34 with a knob is screwed into the screw hole, and a conical tip portion of the screw 34 has the vertical cursor. The two rising pieces 2a are fitted in a conical concave portion. Reference numeral 26 denotes a pair of links formed in a substantially V shape, one end of each of which is a spring hook shaft 68.
And a shaft hole formed substantially in the middle of the link 26 is rotatably fitted to the pivot shaft 8. As shown in FIG. 1, each of the other ends of the links 26 is rotatably connected to a projecting piece provided on the link 4 by a shaft 28.
A hook portion of a spring 32 composed of three coil springs A, B, and C is engaged between the spring hook shaft 68 and a spring hook shaft 72 provided on the slide block 30. The springs 32 have different lengths as shown in FIG. 8, and the hook portions a, b, c at each end are formed slidably with respect to the shaft 68 in the longitudinal direction of the spring by a predetermined distance.
Each of the above-mentioned hooking parts when 18 is at the set highest position
The play (play) amounts G1, G2, and G3 of a, b, and c with respect to the shaft 68 are different from each other. The change characteristics of the spring force with respect to the changing position of the heads 18 in the descending direction of the springs A, B and C are as shown in FIG. 10b, and as a whole, approximated to a quadratic curve as shown in FIG. 10c. It is a characteristic.

Next, the operation of this embodiment will be described. When the handle of the head 18 is gripped by hand and the side surface of the support substrate 20 is in contact with the stopper shaft 22 due to the weight of the head 18, the head 18 is pulled up, and the links 4, 6, 26 are connected to the pivot shaft 8 ,
In FIG. 2, the ring 12 swings counterclockwise about 10 and the link 12 rises substantially parallel to the surface of the drawing board 24 to move the head 18
Rises while being held substantially parallel to the surface of the drawing board.
The moving range of the head 18 in the ascending direction in the parallel state is determined by the protrusion amount of the stopper 64, and when the stopper 64 collides with the side surface of the projecting piece 4a of the link 4, the head is further moved.
The rise of 18 is blocked. When the hand is released from the handle of the head 18 at any rising position within the range where the head 18 can be raised, the weight of the head 18 causes the link 4 to rotate clockwise about the pivot shaft 8 in FIG. Torque is generated. The rotational torque and the rotational torque acting on the link 4 due to the tensile elasticity of the spring 32 are preliminarily adjusted to be substantially the same. For this adjustment, the spring adjusting screw 34 is rotated in accordance with the inclination angle of the drawing plate 24 to move the slide block 30 in the left-right direction in FIG.
This is done by adjusting the deflection amount of 32. As a result, even if the head 18 is released from the hand, the head 18 balances at an arbitrary raised position and does not fall due to its own weight.

Further, in this embodiment, the head 18 lowers the head 18
It is configured to hold this state when it is brought into close contact with the 24 surface.

The torque Mc acting on the link 26 when the head 18 is brought into close contact with the surface of the drawing plate is Mc = F · d, where F is a spring force and d is an arm length perpendicular to the spring. (See Fig. 4) Let r be the arm length, α be the angle of inclination of the arm with respect to the hinge (the line passing through the axes 8 and 70), and let be the angle of inclination of the spring with respect to the horizontal direction. D = r sin (α +) (1)

When k is the spring constant and x is the spring displacement position, F = kx ... (2) Therefore, from the above equations (1) and (2), Mc = kx x r sin (α +) ... (3) Become.

The torque Mf acting on the link 26 when the head is flying is Mf = k (x- [Delta] x) * r sin ([alpha]-[Delta] [alpha] ++ [beta]) from the above equation (3).

Where Δx is the amount of spring displacement when the head is raised, and Δα is
The amount of displacement of the tilt angle between the arm and hinge when the head is raised, β
Is the tilt angle of the hinge with respect to the horizontal.

When the head 18 is levitated from the surface of the drawing board 24, the amount of spring displacement becomes smaller than when the head 18 is in close contact with the drawing board 3, and the tilt angle (α-Δα) between the arm and the hinge also becomes small.

Here, if Δx and Δα are minute and omitted, Mf = kx × r sin (α ++ β) Therefore, Mf / Mc = [kx × r sin (α ++ β)] / [kx × r sin
If the condition (α +)]> 1 is set, the head 18 can be brought into close contact with the surface of the drawing board 24 and can be floated above the drawing board 24.

In the present embodiment, three quadratic curve characteristics shown in FIG. 10C were obtained by the three springs A, B and C showing the spring force change characteristics shown in FIG. 10b. By using three springs A ', B', and C'having the changing characteristics of the spring force with respect to the displacement amount of the head in the descending direction, the spring force with respect to the displacement amount of the spring shown in FIG. It may be configured to obtain the next curve approximate displacement characteristic. The quadratic curve characteristic is not particularly limited to the configuration obtained by a plurality of springs.
As shown, a single tapered conical coil spring 80 may be used. Further, as shown in FIG. 12a, the so-called quadratic or cubic curve characteristic can be obtained also by using a so-called bamboo spring formed by winding a leaf spring 82 whose width decreases in one direction. FIG. 13 shows a coil spring 84 in which the winding diameter is the same and the lead changes in one direction, and the quadratic curve characteristic can be obtained also by this spring.

In this embodiment, the spring is used so that the displacement characteristic of the spring force with respect to the flexural displacement of the spring is a quadratic curve. However, the above characteristic is not required to be a straight line, and therefore, the curve is more curved than the quadratic curve. A spring having a large n-order curve characteristic (n is an integer of 2 or more) may be used.

Further, in this embodiment, when the head 18 is brought into close contact with the surface of the drawing board 24, the head is kept in the close contact state by its own weight. When separated, the head 18 may slightly float above the surface of the drawing board 24 due to the spring force.

〔effect〕

As described above in the present invention, the change characteristic of the spring force with respect to the spring deflection of the spring that urges the head in the direction of rising from the drawing plate surface is set to the nth-order approximation curve characteristic, so that the feeling of lifting / lowering operation of the head is improved. The effect is that the head does not change each time the inclination angle of the drawing board changes, and the head can be operated in the vertical direction with the same feeling of use.

[Brief description of drawings]

1 is a side view, FIG. 2 is a side view, FIG. 3 is a plan view, FIG. 4 is a side view, FIGS. 5a and 5b are side views, and FIG. 6 is a sectional view.
FIG. 7 is a sectional view, FIG. 8 is an explanatory view, FIG. 9 is a plan view,
10 a, b, c, d, e are explanatory views, FIG. 11 is a front view, FIGS. 12 a and b are external views, FIG. 13 is an external view, FIG. 14 is an explanatory view, and FIG. 15 is FIG. 2 …… Vertical cursor, 2a …… Standing piece, 4,6 …… Link, 8,
10 …… Axis, 12 …… Link, 14,16 …… Axis, 18 …… Head, 20 …… Board, 22 …… Stopper axis, 24 …… Drawing board, 26 ……
Link 28, Axis, 30 Slide block, 32 Coil spring, 34 Adjust screw, 40 Horizontal rail, 42 Horizontal cursor, 44 Vertical rail, 46 Vertical support device, 48 …… Ruler mounting plate, 50, 52 …… Straight ruler, 54, 56 …… Pivot bearing, 58,
60 …… Pivot bearing, 62 …… Pivot shaft, 64 …… Stopper, 66 …… Guide pin, 68 …… Spring hook shaft, 72 ……
Spring hook shaft, 80, 82 ...... spring

Claims (1)

[Claims] 1. A horizontal rail 40, a vertical rail 44 which is movably connectable to the horizontal rail 40 at a right angle, and the vertical rail.
A vertical cursor 2 movably attached to 44, and a link 26 pivotally supported on the vertical cursor 2 so as to be swingable in a vertical direction.
A head 18 which is linked to the swing end side of the link 26 so as to interlock with the swing of the link 26, a spring which biases the link 26 in the ascending direction and has a fulcrum on the vertical cursor 2 side. In a device including a spring 32 and a spring force adjusting unit that adjusts the elastic force of the spring 32, the spring 32 has a n-th order approximate curve characteristic (n
Is an integer greater than or equal to 2).