JPH0423678Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention provides a universal parallel ruler that, when the ruler is free from the non-rotating member of the head on an inclined drawing board, the ruler moves slightly along the drawing board in the falling direction. This invention relates to a ruler balancing device for perfect balance, which allows the ruler to maintain a stable stationary state.

Perfect balance here means that the rotational force in the rotational direction of the rotating body due to the weight of the ruler, etc., and the rotational force acting on the rotating body in the opposite direction to this rotational force are the same over the entire rotation range of the ruler. When the two rotational forces cancel each other out and the straight edge is free, the straight edge will remain stationary on the inclined drawing board and will not move slightly.

As this type of device, a scale support device for a universal parallel ruler disclosed in Japanese Utility Model Publication No. 52-28605 is known. In the above device, the elastic force of the spring is applied to the cam through the rollers, and an elastic force is applied to the scale mounting plate in a direction opposite to the direction of fall rotation.
However, with this configuration, in order to achieve perfect balance of the scale mounting plate, high precision is required in the shape of the cam, making it difficult to design and process the cam surface, resulting in high manufacturing costs. There was a drawback that assembly and adjustment were not easy.

SUMMARY OF THE INVENTION An object of the present invention is to provide a ruler balancing device that has a simple structure, is suitable for miniaturization, and is capable of setting the ruler in a perfectly balanced state.

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

Reference numeral 2 denotes a drawing board, which is supported by a support frame of a drafting table which can be tilted freely so as to be fixed at a desired angle of inclination. 4 is a horizontal rail arranged on the upper side of the drawing board 2, and a horizontal cursor 6 is movably attached to this rail. The upper end of the vertical rail 8 is connected to the horizontal cursor 6. The lower end of the vertical rail 8 is movably disposed on the drawing board 2 via a tail roller. 12 is a vertical cursor movably attached to the vertical rail 8, and a supporting substrate 18 of the head 16 is attached to this via a known double hinge mechanism 14.
are connected. A multiaxial tube 20 is fixed to the tube portion of the support substrate 18 with a nut. 22
is a main shaft pipe, and the outer circumferential surface of this is the same as the multiaxial pipe 20.
is rotatably fitted into the inner circumferential surface of the main shaft tube 2.
A mounting plate 24 is fixed to the upper part of 2 with nuts. A grip handle 26 is provided on the mounting plate 24.
is fixed. Reference numeral 28 denotes an index lever, one end of which is coupled with a play to the upper end of a conical rod 30 disposed within the main shaft tube 22. 32 is a stationary plate fixed to the support substrate 18; 34 is a protractor rotatably fitted to the outer peripheral surface of the flange of the multi-axis tube 20; the protractor 34 has a fixing mechanism ( (not shown) is fixed to the fixed platen 32. 36 is the protractor board 3
4, and index recesses 38 are bored at predetermined intervals on the outer periphery of the index ring. Reference numeral 40 denotes a substrate fixed to the flange of the main shaft tube 22, and a ruler mounting plate 42 is attached to this. 44 has a shaft 46 at one end.
This is a swinging arm rotatably supported by the substrate 40, and a claw portion 44a of this swinging arm is fitted into one of the index recesses 38. The conical rod 3
One end of a transmission member 48 is connected to the lower end of the transmission member 48, and a shaft body 50 fixed to the other end of the transmission member 48 is fitted into a long groove transparently provided in the swing arm 44. The transmission member 48 is operated by a spring member 52 as shown in FIG.
It is biased towards the left. the index lever 28, the conical rod 30, the index ring 36,
The swinging arm 44 and the transmission member 48 constitute means for fixing and unfixing the board 40 to the protractor 34. Straight rulers 52 and 54 are removably fixed to the ruler mounting plate 42. 56 is the substrate 40
58 is a top cover attached to cover 56. The above support substrate 1
8. The fixed plate 32, the protractor plate 34, the index ring 36, and the multi-axis tube 20 each constitute a non-rotating member of the head. 60 is a tubular body fixed to the mounting plate 24, and teeth 60a are fixedly provided at the lower part of the tubular body 60. The rotation center of the teeth 60a and the rotation center of the main shaft tube 22 coincide. 62 is
This is a gear rotatably supported by a shaft 64 on the support substrate 18, and the gear 62 meshes with the teeth 60a. Reference numeral 66 denotes a guide groove formed in the main body of the gear 62 to be elongated in the radial direction of the main body, and a bridge member 68 is disposed in the guide groove so as to be slidable along the longitudinal direction of the guide groove 66. 70 is a screw shaft rotatably supported by the main body of the gear 62;
0 is screwed into the screw hole of the bridge member 68. A molding 72 is fixed to one end of the screw shaft 70. In FIG. 3, 74 is a cylindrical body whose one end opening is fixed to the support substrate 18, and a plate member 76 is slidably disposed inside this cylindrical body. A coil spring 78 is compressed and disposed within the cylinder 74, and one end of the coil spring is in elastic contact with the plate member 76. Reference numeral 80 denotes a rope guide consisting of a rope pulley rotatably supported by a shaft 18 on the support substrate 18, and a flexible and bendable wire rope 82 is hung thereon. Said rope 8
One end of 2 is connected to the plate member 76. A metal terminal 84 is fixed to the other end of the rope 82,
The terminal 84 is connected to the protrusion of the bridge member 68. When the terminal 84 is positioned at the rope regulating end of the rope guide 80, the spring 7
The amount of deflection of the spring 78 is set so that the tension of the rope 82 due to the
2 and a spring constant corresponding to the weight of the straightedges 52 and 54 is adopted. The cylinder body 7
4, the spring 78 and the rod 82 constitute biasing means.

Next, the operation of this embodiment will be explained.

First, the drawing board 2 is set at a desired inclination angle in the upright direction with respect to the floor surface. Handle 26 of head 16
When the handle 26 is pressed in an arbitrary direction parallel to the surface of the drawing board 2 by grasping it with a hand, the head 16 can be moved in parallel to a desired location on the drawing board 2. When the index lever 28 is manually moved to the left with the head 16 stationary at an arbitrary position on the drawing board 2, the conical rod 30 moves toward the ampulla 30.
The transmission member 48 swings counterclockwise in FIG. 2 with a as a fulcrum, and the transmission member 48 moves rightward. As a result, the swinging arm 44 swings about the shaft 46 in the direction of rotation of the hour hand in FIG. It is in a state where it can freely rotate around the tube 20. That is, the ruler mounting plate 42
Fixation to the non-rotating member is released. In this state, due to the weight of the base plate 40, the ruler mounting plate 42, the straightedges 52, 54, etc., a rotational torque T' centered on the shaft 64 is applied to the gear 62, that is, the rotating body 62 interlocking with the ruler mounting plate 42. Occur. This rotational torque T' and the rotational torque T acting on the rotating body due to the elasticity of the spring 78 have the same magnitude and are opposite in direction. Therefore, the straightedge 52,
54 remains stationary on the drawing board 2 even in a free rotation state and does not rotate suddenly due to its own weight.

The above operation will be explained in more detail with reference to the explanatory diagram of FIG.

A rotating body 62 that rotates in conjunction with the ruler mounting plate rotates around a point P, that is, the center point of the shaft 64 shown in FIG. In the state where the rope is being stretched, the state where the above point C and the rope regulating end E of the guide 80 are at the shortest distance is defined as zero degree,
Let us consider the rotational torque T generated in the rotating body 62 by the spring 78 when the rotating body 62 is rotated by an angle θ. First, the strength F of the spring 78 when the rotating body 62 rotates by an angle θ is, where k is the spring constant of the spring 78 and x is the amount of extension of the spring 78, when the angle θ of the rotating body 62 is zero degrees.
When the elasticity of the spring 78 is set to zero, F=kx=k(la).

Here, a is the rotation center P and the rotation center E
When the point where the axis L passing through and the rotation locus of the rope connection point C intersects is C', the distance between E and C' is shown. Moreover, l is the distance between the connection point C and the rotation center E when the rotating body 62 rotates by θ angle from zero degrees. Now, when r is the distance between P and C', and α is the angle formed by the axis L and the line segment EC, the above l can be determined by the following formula.

l={(r.sinθ) ² + (r+a−rcosθ ² )} ^1/2 = [r ² sin ² θ+{r(1−cosθ)+a} ² ] ^1/2 = {r ² sin ² θ+r ² ( 1-2 cos θ + cos ² θ) + 2ra (1
−cosθ)+a ² } ^1/2 = {(r ² sin ² θ+r ² −2r ² cosθ+r ² cos ² θ+2ra−2ra
cos θ + a ² } ^1/2 = {r ² (sin ² θ + cos ² θ) + r ² −2r ² cos θ + 2ra (1
-cosθ)+a ² } ^1/2 = {2r ² -2r ² cosθ+2ra (1-cosθ) + a ² } ^1/2 = {2r ² (1-cosθ) + 2ra (1-cosθ) + a ² } ^1/2 = {(1−cosθ)(2r ² +2ra)+a ² } ^1/2 Also, the rotation radius R required to rotate the rotating body by the tension of the rope 82 is determined as R = (a + r) sin α be able to.
Transforming this, R=(a+r)rsinθ/l The torque T that rotates the rotating body 62 due to the extension of the spring 78 is T=F×R, so if we insert the above values of F and R into this equation, T=k (la)(a+r)r・sinθ/l.

When a=0, T=kr ² sinθ. kr is constant, and from this equation it can be seen that T is a function of sin θ. here,
As shown in FIG. 9, w is the center of gravity G on the substrate 40,
If r' is the distance between the center of gravity G and the center of rotation of the board 40, and the load due to the weight of the straightedge, etc. is applied in the direction in which the board 40 is rotated, then the horizontal straightedge 52 (see FIG. 1) is connected to the vertical rail 8. the substrate 40 until it becomes approximately parallel.
When the state of the substrate 40 in which the load w does not act on the substrate 40 as a rotational torque is set to zero degrees, the rotational torque T' generated by the load w when the substrate 40 is rotated by θ degrees is T' = wr′sinθ.

The value of wr′ is constant, and from this the torque T′ becomes
It turns out that sin θ.

This shows that when a=0, the forward and reverse rotational torques T and T' of the rotating body 62 can be perfectly balanced. Furthermore, as shown in Fig. 10, the torque change when the above r is shortened is as follows: When the above l={(1-cosθ)(2r ² +2r・a) +a ² } ^1/2 is changed, l= {(1−cosθ)(2r ² s+2rsb) +b ² } becomes ^1/2 .

In addition, rs is the rotation center of the rotating body 62 and the rope connection point C
b is the distance between the rope restriction point E of the guide 80 and the rope connection point C' when the rotating body 62 is at zero degrees. Incidentally, assuming that the rope 82 is removed from the rotating body 62 and the rope connection point C is moved to point D, the tension in the rope 82 becomes zero. The distance between this point D and the rope regulating end E of the guide 80 is a', and the point D
If the distance between the rope connection point C' and the rope connection point C' is d, the above b is expressed as b=(a'+d).

The actual extension lr of spring 78 is lr=(l-b)+d The strength F of the spring 78 is F=K(l-b+d).

In addition, the rotating body 6 as a rotating torque generating element
The radius of rotation R assumed on 2 is: R=(a'+r)sinα=(a'+r)rs・sinθ/l Therefore, the rotational torque T generated on the rotating body 62 by the spring 78 is: T= F×R =k(l-b+d)(a'+r)rs·sinθ/l.

Since the value of l changes depending on the rotation angle of the rotating body 62, the change characteristic of the rotational torque T generated on the rotating body 62 by the spring 78 does not form a sin θ curve. However, since the change characteristic of the rotational torque T' generated on the rotating body 62 due to the weight of the straightedge etc. as the straightedge rotates forms a sin θ curve, the rotational torque generated on the rotating body 62 in the forward and reverse directions is balanced. I can't do it. however,
In FIG. 10, the rope is removed from the rotating body 62, and the rope connection point C to the rotating body 62 is shown.
If the elasticity of the spring 78 is set to be zero when the rope is brought to the rope regulating end E of the rope guide 80, the rope connecting point C to the rotating body 62 of this rope is connected to the rotating body 62. In this case, the spring force F of the spring 78 can be found as F=kl. Here, H is the distance between point E and the rotation center P of the rotating body, and rs is the rod connection point C and P.
The extension l of the spring 78 is l=√ ² + ² −2 .

The radius of rotation R assumed on the rotating body 62 as a rotational torque generating element by the spring 78 is R=H・sinα and x=l・sinα=r・sinθ, so R=H・rs・sinθ/l From this, the rotational torque T generated on the rotating body 62 by the spring force of the spring 78 is: T = kl x R = kl x H・rs・sinθ/l = kHrsinθ Thereby, the rotational torque T due to the spring 78 is sinθ x constant This becomes a SIN curve.

From the above equation, the connecting point C of the rope to the rotating body 62 is removed from the rotating body 62 and the guide 80
If the amount of deflection of the spring 78 is set so that the elasticity of the spring 78 becomes zero when the rope moves to the rope restriction end E, the rotation body 6 of the rope
Even if the connection point C for 2 is set at any position on the rotating body 62, the spring 78
It can be seen that the change characteristics of the rotational torque T that occurs in can be made into a SIN curve. Furthermore, if the connection point C is set at the rotation center of the rotating body 62 and b=0,
T=0. As shown in Fig. 11, if the rope guide is not provided and it is assumed that the rope guide is infinitely far away from the rotating body, the spring force of the spring = k (rs - rs ・ cos θ) = krs (1 −cosθ). In addition, since the rotational radius R assumed on the rotating body as a rotational torque generating element by the spring is R = rs · sin θ, the rotational torque T generated on the rotating body by the tensile force of the spring is T = krs (1 −cos θ)×rs・sin θ=k・rs ²・sin θ (1−cos θ) Therefore, the change characteristic of the rotational torque T does not form a sin curve as shown in FIG.

Next, the operation for adjusting the rotation radius R will be explained.

When the molding 72 is rotated, the screw shaft 70 is rotated. As a result, the bridge member 68 moves along the guide groove 66, and the rope terminal 84 moves in the radial direction on the rotating body 62 in conjunction with the bridge member 68.
As the rope terminal 84 moves, the distance between the rope connection point C and the center of the rotating body 62 changes. When the inclination angle of the drawing board is changed, the value of the load W applied to the board 40 due to the weight of the straight edge or the like changes in accordance with this change. Therefore, when the inclination angle of the drawing board 2 is changed, the molding 72
By adjusting the rotation, the magnitude of the rotational torque T generated on the rotation body 62 by the tensile load F of the spring 78 is made to match the rotation torque T' generated on the rotation body 62 due to the load W. be able to.

Next, another embodiment of the present invention will be described with reference to FIGS. 6 and 7.

100 is a bracket, the vertical part 10 of this
The lower end of 0a is connected to the support substrate 104 by screws 102.
is fixed. Vertical part 1 of bracket 100
Vertical rope pulleys 10 are installed at the upper and lower ends of 00a.
6 and 108 are rotatably supported. The upper end of the vertical portion 100a is connected to the rope pulley 106.
A rope guide 110 consisting of a horizontal rope pulley is rotatably supported adjacent to the rope guide 110 .

Reference numeral 116 is a screw rod that is rotatably inserted into a horizontal hole 114 provided through the side wall of the handle 112 (rotating body), and a molding 118 is fixed to one end of this rod. One surface of the molding 118 rotatably abuts a counterbore 120 formed in the handle 112. Reference numeral 122 denotes a frame body, into which the threaded rods 116 are rotatably fitted into holes formed through a pair of side walls of the frame body, and protrusions 124 in the form of disk strips protruding from the bottom wall of the frame body 122 are inserted into holes formed through the pair of side walls of the frame body. It is rotatably fitted into a hole 126 provided in a horizontal portion of the bracket 100. The center of the hole 126 is located at the handle 11.
It coincides with the center of rotation of 2. The upper end of the frame 122 is in contact with the lower surface of the cab 112a of the handle 112. Reference numeral 128 designates a piece member that is screwed into the screw rod 116, and a shaft body 130 is fixed to the lower end of this piece member, and a terminal 134 of a wire rope 132 is fitted into the shaft body 130. The screw rod 116 is configured to not move in the axial direction of the screw rod 116 with respect to the frame 122 by a stopper ring. The lower end of the shaft body 130 is connected to the frame body 13
4, and one side and the top surface of the bridge member 128 are respectively connected to the frame 122.
The vertical side of the handle 112 and the cap 12 of the handle 112
It is in slidable contact with the lower surface of 2a. 14
0 is a coil spring whose one end is screwed to the support substrate 104, and the other end of which is connected to one end of a flexible wire rope 132.
The wire rope 132 is connected to the pulleys 108, 106
and is hung on the rope guide 110, and the terminal 134 is connected to the other end.

The internal structure of the head is the same as that shown in FIG. 2, so a description thereof will be omitted.

In the above configuration, the terminal 134 is connected to the shaft body 13
0 and move the center point of the hole of the terminal 134 to the rope regulating end E of the rope guide.
The effective length, that is, the amount of deflection, of the spring 140 is set so that the elasticity of the spring 140 is zero. Also, on the inclined drawing board,
12 on the top of Figure 7, horizontal straightedge 5 in the counterclockwise direction of rotation of the hour hand.
2 rotates until it becomes substantially parallel to the vertical rail 8 (see Figure 1), and when the rotational torque T' generated in the handle 112 due to the weight of the straightedges 52, 54, etc. is zero, the terminal 134 is rope guide 1
06, and the rotation radius R of the handle 112 by the spring 140 as a rotational torque generating element is set to be zero. Due to the weight of the straightedge, ruler mounting plate, etc., the seventh
In the figure, rotational torque T' generated in the clockwise direction is transmitted to the handle 112 (rotating body) via the main shaft tube 22. On the other hand, the tensile force of the spring 78 is
A rotational torque T is transmitted to the handle 112 via the rope 132 and the bridge member 128, and is generated in the handle 112 by the tensile force of the spring 140 in the counterclockwise direction of rotation of the hour hand in FIG. When the drawing board is fixed at a predetermined inclination angle, the magnitudes of the rotational torques T and T' are set to be the same, and when the straight edge is free, it rests on the inclined drawing board and is perfectly balanced. do. When the inclination angle of the drawing board is changed, the magnitude of the rotational torque T' changes. In this case, by rotating the molding 118, the piece member 1
28 is moved in the radial direction of the handle 112 along the threaded rod 116 to match the magnitude of the rotational torque T' with the magnitude of the rotational torque T.

The operation of the present invention can be summarized as follows with reference to FIG.

In FIG. 8, the rope connection point C is connected to the rotating body 62.
When the connection point C is brought to the rope regulating end E, the spring 78 is set in an unloaded state, that is, the amount of deflection is zero, and the rope connection C is connected to the eccentric point of the rotating body 62. If EC
The distance l is the amount of deflection of the spring 78.

The spring force F of the spring 78 exerted by the rotating body 62 can be set as F=kl. Here k is a spring constant. Further, if the torque radius applied to the rotating body 62 by the above spring force is R, the torque radius R can be set as R=(a+r)sinα, and this formula is expressed as follows: The law of sine of triangle PCE r/sinα= From l/sinθ, we can derive R=(a+r)・r・sinθ/l. If the torque due to the above spring force F on the rotating body 62 is T, then T=F・R=kl・(a+r)・r・sinθ/l=k(a+r)・r・sinθ Here, the above k, a, r are Since it is a constant,
Torque T is a function of sinθ.

That is, when the ruler mounting plate 42 is in a free rotation state with respect to the non-rotating member 18, the rotational torque generated in the rotating body 62 due to the weight of the rulers 52, 54, etc. will follow the curve of sin θ as the rotating body 62 rotates. However, the balance force of the rotating body 62 that offsets this rotational torque also changes by sin θ, and the rotating body 62 is perfectly balanced at any rotation angle.

As mentioned above, the present invention does not use a cam,
By supporting the rope on the board side via a spring and connecting the rope to the rotating body, it is possible to achieve perfect balance of the straightedge, reducing manufacturing costs and making it easy to manufacture. There is an effect that can be achieved.

[Brief explanation of drawings]

Figure 1 is a plan view, Figure 2 is a vertical sectional view, Figure 3 is a cross sectional view, Figure 4 is a sectional view taken along line A-A, and Figure 5 is B.
6 is a vertical sectional view showing another embodiment, FIG. 7 is a horizontal sectional view, FIG. 8 is an explanatory view, FIG. 9 is an explanatory view, FIG. 10 is an explanatory view, FIG. 11 is an explanatory diagram, and FIG. 12 is a torque characteristic diagram. 2...Drawing board, 4...Horizontal rail, 6...Horizontal cursor, 8...Vertical rail, 10...Tail roller, 12...
... Vertical cursor, 14 ... Hinge mechanism, 16 ... Head, 18 ... Support board, 20 ... Multi-axis tube, 22
... Main shaft tube, 24 ... Mounting plate, 26 ... Grip handle, 28 ... Index lever, 30 ... Conical rod, 2 ... Fixed plate, 34 ... Protractor board, 36 ...
Index ring, 40... Board, 42... Ruler mounting plate, 52, 54... Ruler, 60... Tube body,
62... Rotating body, 78... Spring, 80...
Rope guide, 82...Wire rope, 140...
…coil spring.

Claims (1)

[Scope of utility model registration request] A head 16 that can be moved to any position on the drawing board 2 while maintaining a predetermined orientation;
In the universal parallel ruler, the non-rotating member 18 of the head 16 includes a ruler mounting plate 42 rotatably mounted on the non-rotating member 18, 104 of the head 16, and rulers 52, 54 mounted on the ruler mounting plate 42. ,1
A rope guide 80, 110 is provided on the 04 side, and one end side of the rope 82, 132 is connected to the non-rotating member 18,
104 side via springs 78, 140, and when the other end of the rope 82, 132 is positioned in the rope guide 80, 110, the amount of deflection of the spring 78, 140 becomes zero. 82, 132 are hung on the rope guides 80, 110, and the rotating body 62 is rotatably supported on the non-rotating member 18 so as to rotate in conjunction with the rotation of the rulers 52, 54 relative to the non-rotating member 18, The rulers 52 and 54 of the rotating body 62
A balancing device for a ruler, characterized in that the other ends of the ropes 82, 132 are connected so that the biasing force of the springs 78, 140 acts in a direction opposite to the direction of rotation due to the weight of the ruler.