JPH034560Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a head support device for a universal parallel ruler that can support the head and scale above the drawing surface.

Conventionally, devices of this type have been known in which a spring member is used to press the head portion upward, but in this case, the pressing force of the spring member is maximum when the head portion is in close contact with the drawing surface, and the head portion is pressed upward. As the head becomes weaker as it moves upward, it has the disadvantage that when the angle of inclination of the drawing board increases with respect to the horizontal, the head part no longer comes into close contact with the drawing board surface.

Further, Japanese Utility Model Publication No. 50-37875 discloses a device in which the spring member is configured as a constant force spring so that the spring elasticity does not decrease as the scale and head rise. Theoretically, the same upward force will be applied to the head support when the head is floating and when it is in close contact with the drawing surface, so if the spring force is set strong, the head will There is a problem that the surface remains stuck.

As a conventional device to eliminate this drawback, for example, as described in Japanese Patent Application Laid-Open No. 55-126497, a cam member having an inclination such that the head portion moves upward and an inclination such that the head portion moves downward is used. There is a known structure in which a push member and a spring member are used to apply push-up or push-down elasticity, but not only is the structure complicated, but since there is switching between push-up and push-down, it is difficult to smoothly move the head up and down. There was a problem with the lack of quality.

Furthermore, in Japanese Patent Application Laid-Open No. 54-10025, a head support link is connected to a cursor side link by an upper link and a lower link to a quadrilateral link mechanism, and the head support link is connected to the upper link by its own weight. For example, a cam surface formed with a special curvature on the center upper surface of the lower link comes into contact with a roller provided at the center lower part of the upper link to act as a head supporting force to reduce the downward rotational moment. In addition, a structure in which the intermediate portions of the upper link and the lower link are connected by a link piece and acts as a head supporting force through the link piece is shown, but the link structure for supporting the head is complicated, Further, there were problems such as difficulty in adjusting the head supporting force.

Therefore, in order to solve the problems of the conventional device, the present invention connects one end of the upper link to the cursor side link in a swingable manner, and integrates the head part and the scale in a swingable manner to the other end of the upper link. In a flexible parallel ruler formed by connecting head support links, a support lever is provided that moves up and down using the cursor side link as a swinging fulcrum, and the tip of the support lever is in contact with the head support link at two points. A two-point support part is provided to support the head part and scale approximately parallel to the drawing surface, and a two-point support part is provided between the support lever and the cursor side link. The present invention provides a head support device for a universal parallel ruler that is provided with a tension spring means for applying a push-up force.

The device of the present invention will be described in detail with reference to the embodiments shown below. Reference numeral 1 denotes a cursor side link which is integrally fixed onto a cursor plate 2 with a fixing screw or the like. The cursor plate 2 is movably supported by running rollers 5 that engage with guide rails 4 of the vertical rails 3. A head support link 6 supports a head section 7 for operating the scale 8, and is connected to the cursor side link 1 via an upper link 9.
In the case of the embodiment, the upper parts of both the links 1 and 6 are respectively connected to both ends of the upper link 9 by pivot shafts 10a and 10b parallel to the vertical rail, and the upper link 9 swings about the pivot shaft 10a. In addition, the head support link 6 is configured to be swingable about a pivot 10b relative to the upper link.

Therefore, in this state, the upper link 9 freely rotates with respect to the cursor side link 1, and the head support link 6 freely rotates with respect to the upper link 9.
In this state, the head support link 6 cannot be moved up and down parallel to the drawing surface.

Here, reference numeral 11 denotes a mounting board that is integrally attached to the cursor side link 1 with fixing screws 12, and supports a support lever 14 so as to be able to swing around a swing fulcrum shaft 13 that is parallel to the pivots 10a and 10b. . The support lever 14 forms a pair with the upper link 9 and functions as a conventional lower link for moving the head support link 6 up and down parallel to the drawing board surface. A roller 15 is rotatably provided at the tip of the support lever 14 and supports the head support link 6.
It is slidably abutted on the contact surface 6a of. Also,
The tip of the support lever 14 is bent downward to form a guide support surface 16, and the head support link 6
It is in contact with a roller 17 that is rotatably provided. These rollers 15, guide support surface 16, and contact surface 6a
The relationship between the rollers 17 and 17 is such that a two-point support part supports the head support link 6, which swings about the pivot shaft 10b as the support lever 14 swings, so as to move up and down approximately parallel to the drawing surface. It consists of In this case, the contact position of the roller 15 on the contact surface 6a is
If it is closer to the cursor than 0b (left side in the figure), the guide support surface 16 and rollers 17 will have strong adhesion, and if it is closer to the head than the pivot 10b (right side in the figure), the guide support surface 16 and rollers 17 will be in close contact. Since the contact will be light, by appropriately setting the contact position between the roller 15 and the contact surface 6a, for example, as shown in FIGS.
In the state shown in the figure, the head support link 6 is securely supported so as not to rotate around the pivot shaft 10b, and in the state shown in FIGS.
The support state of the head support link 6 by the support lever 14 can be adjusted so that the head support link 6 is supported in a state where it can easily rotate counterclockwise around 0b.
In either case, the head support link 6 is supported at two points to prevent it from rotating downward when it is out of parallel to the support lever 14, so it is difficult to break the head support link 6 out of parallel when replacing or cleaning drawings. You can freely rotate it so that it stands up.

On the other hand, the present invention is characterized by a structure in which a tension spring means is provided between the support lever 14 and the cursor-side link 6 to apply a pushing force to the support lever that increases as the head portion and the scale move upward. shall be.

That is, the spring-loaded shaft 1 is attached to the tip of the support lever 14.
8 is provided, and a spring hanging shaft 19 is also provided on the mounting board 11, and these spring hanging shafts 18,
A spring member 20 having tensile elasticity is stretched between 19 and serves as a tension spring means.

For convenience of explanation, a line connecting the swing fulcrum shaft 13 of the support lever 14 and the spring hanging shaft 18 and a line connecting the spring hanging shaft 1
The angle formed by the line connecting 8 and 19, that is, the angle between the swinging fulcrum shaft 13 of the support lever and the spring member 2 on the support lever 14.
0 connects the spring hanging shaft 18, which is the point of application of tensile force, and the support shafts 18 and 19, which are the points of application of the tensile force of the spring member that determine the direction of tension of the spring member 20.
The angle formed by the line connecting the two is defined as the tension angle by the spring member 20 that pulls the support lever in the upward direction.

In the case of the embodiment, the spring member 20 has a tension angle that is equal to the swing fulcrum shaft 13 of the support lever 14 and the spring hanging shaft 1 when the head portion and the scale are in contact with the drawing surface.
8, and the tension angle increases as the head and scale float above the drawing board, and the increased spring action force in the floating position causes the head to It is constructed to be able to support the parts and scales.

To explain this point with reference to FIG. 6, the support lever 14 rotates at an angle θ around the swing fulcrum 13, and the spring member 20 stretched between the support shafts 18 and 19 generates a tensile elasticity F at a tension angle α. When applied to the support lever 14, the upward rotational moment M acting on the support lever 14 is caused by the tensile elasticity F from the swing fulcrum 13.
If the length of the perpendicular line drawn to is a, then M=Fa, and a is the length of the swing fulcrum 13 and the support shaft 18, a=Lsinα, so the support lever 14
The rotational moment M in the push-up direction applied to is M=FLsinα. Also, as is clear from the figure, the tensile angle α
increases with the upward rotation angle θ of the support lever 14.

Therefore, when the tension angle α=0, M=0,
For example, when α=5°, M=0.09FL, when α=10°, M=0.17FL, when α=15°, M=0.26FL, α=
As is clear from the fact that M=0.5FL at 30 degrees, the upward force exerted by the spring member 20 increases as the support lever 14 swings upward along the sine curve. Further, the length of the spring member 20 decreases as the tension angle α increases, but the rate of decrease is small compared to the length of the spring member 20 to which tensile elasticity is applied. Therefore, the decrease in tensile elasticity, which affects the pushing-up force which increases significantly, can be set within a negligible range.

The gist of the present invention is that the support lever is provided with a tension spring means that applies a push-up force that increases as the head portion and the scale move upward. This is realized by a configuration in which the tension angle α by the tensioning spring member 20 increases as the head portion and the scale move upward from the drawing surface, and the tension angle α
Whether or not the head portion and the scale increase as the head portion and scale move upward from the drawing surface is determined by the sixth point.
In the figure, once the swing fulcrum 13 of the support lever 14 and the application points 18 and 19 of the spring member 20 are determined, the tension angle α can also be uniformly determined geometrically as the rotation angle θ of the support lever 14 changes. This can be clearly recognized from the following.

In addition, in the case of the embodiment, in order to limit the swing range of the support lever 14, the upper limit stopper 21 that abuts at the upper limit position and the lower limit stopper 22 that abuts at the lower limit position are attached to the mounting board 1 of the cursor side link 1, respectively.
1, and when the support lever 14 is at the upper limit position, the tension angle of the spring member 20 is maximum and the head part and scale are supported in a floating state above the drawing board, and when the support lever 14 is at the lower limit position. Although the tension angle is close to zero, the lower limit stopper 22 is contacted at an angle where an upward force is applied, and the head portion and scale are set to come into close contact with the drawing surface due to their own weight.

Further, reference numeral 23 denotes a reinforcing lever disposed in parallel with the support lever 14, which is detachably engaged with the support lever 14 to appropriately reinforce the supporting force of the support lever. In the case of the embodiment, the reinforcing lever 23 is swingably supported by the swinging fulcrum shaft 13, and the abutting pin 24 is configured to abut against the lower side of the support lever 14 in the upward swinging position. There is. Further, a spring hanging shaft 25 is provided at the upper end of the reinforcing lever 23, and a reinforcing spring 26 biased with tensile elasticity is provided between the spring hanging shaft 25 and the spring hanging shaft 19 on the mounting board 11.
is set up. As shown in FIGS. 4 and 5, when the reinforcing lever 23 is in the upward swinging position, the reinforcing spring 26 is positioned so that the line connecting the spring hanging shafts 19 and 25 is located above the swinging fulcrum shaft 13, and the reinforcing lever 23 in the counterclockwise direction to apply a supporting force to the support lever 14 via the abutting pin 24, and as shown in FIGS. 2 and 3, When the reinforcing lever 23 is in the position, a clockwise rotating force is applied to the reinforcing lever 23, and the lower side of the reinforcing lever 23 is moved to the stopper 2.
1 and is retracted to a position away from the support lever 14. 27 is an operating piece for attaching and detaching the reinforcing lever 23 to and from the support lever 14.

To explain how the device of the present invention having the above configuration is used, at the position where the head portion and the scale are in contact with the drawing board surface, the spring-loaded shaft 1 is placed as shown in FIG.
The spring member 20 stretched between 8 and 19 is located above the swing fulcrum shaft 13 of the support lever 14.
Since the tension angle is small with respect to the line connecting the swing fulcrum shaft 13 and the spring-loaded shaft 18, the spring acting force that rotates the support lever 14 upward (counterclockwise) does not act strongly, and the support lever 14 With the rollers 15 and the guide support surface 16 in contact with the contact surface 6a of the head support link 6 and the rollers 17, the head portion 7
And the bottom surface of the scale 8 is brought into close contact with the drawing surface. Here, when the head and scale are lifted and released, the head support link 6 attempts to rotate clockwise around the pivot 10a due to the load, but the support lever 14 guides the roller 15. This is supported at two points on the support surface 16, and the head portion and scale are maintained upward while maintaining an attitude substantially parallel to the drawing surface. In this case, as the head support link 6 moves upward, as the head support link 6 moves upward, the tension angle of the spring member 20 increases, thereby increasing the spring elasticity acting on the support lever 14. The head portion and scale are reliably supported in an upwardly floating state.

If the spring elasticity of the spring member 20 is insufficient to provide sufficient support, push up the reinforcing lever 23 upward (counterclockwise) as shown in FIGS. 4 and 5. Support lever 14 for connecting pin 24
When the lever 23 is brought into contact with the lower side of the scale, the spring acting force of the reinforcing spring 26 of the reinforcing lever 23 is applied to the supporting lever 14, which more easily lifts the head and the scale upward and supports it in a floating state. becomes possible.

As described above, according to the device of the present invention, one end of the upper link is swingably connected to the cursor side link, and the other end of the upper link is integrally provided with the swingably head part and the scale. In a flexible parallel ruler formed by connecting support links, a support lever is provided that moves up and down using the cursor side link as a swinging fulcrum, and the tip of the support lever contacts the head support link at two points to connect the head portion and the scale. A two-point support section is provided that supports the scale approximately parallel to the drawing surface, and a pushing force that increases as the head section and scale move upward is provided between the support lever and the cursor side link. Since the structure includes a tension spring means for biasing the head part and the scale, the head support link supporting the head part and the scale can be supported substantially in parallel only by the support lever without using the lower link, and the drawings can be exchanged. This has the effect of allowing the head support link to be freely rotated so as to break parallel and stand up during cleaning, while at the same time allowing the support force of the spring member tensioned on the support lever to move the scale upward from the drawing surface. By increasing the scale accordingly, the head portion and the scale can be brought into close contact with each other on the drawing surface, and the floating state can be smoothly maintained above the drawing surface.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view showing a main part of an embodiment of the present invention, FIGS. 2 and 3 are schematic longitudinal sectional front views partially showing how the main part operates, and FIGS. FIG. 5 is a schematic longitudinal sectional front view showing another operating mode of the main part, and FIG. 6 is an explanatory view for explaining the principle of the operation of the main part of the device of the present invention. 1... Cursor side link, 2... Cursor board,
6...Head support link, 7...Head portion, 8...
...Scale, 9...Top link, 10a, 10b
... Pivot, 11 ... Mounting board, 13 ... Swing fulcrum shaft, 14 ... Support lever, 15 ... Roller, 16 ...
...Guide support surface, 17... Roller, 18, 19... Spring hanging shaft, 20... Spring member, 23... Reinforcement lever, 24... Contact pin, 25... Spring hanging shaft, 26
...Reinforcement spring.

Claims (1)

[Scope of utility model registration request] A flexible parallel ruler in which one end of an upper link is swingably connected to a cursor side link, and a head support link that is swingably connected to the other end of the upper link is integrally provided with a head part and a scale. A support lever is provided that moves up and down using the cursor side link as a swinging fulcrum, and the tip of the support lever abuts the head support link at two points to support the head and scale approximately parallel to the drawing surface. On the other hand, a tension spring means is provided between the support lever and the cursor side link to apply a push-up force to the support lever that increases as the head section and the scale move upward. Head support device for parallel rulers.