JPH041099A - Brake device of drawing head - Google Patents

Abstract

PURPOSE:To reduce operation force by enhancing braking force and to facilitate processing and assembling by providing the brake disc integrally revolving along with a protraction disc and providing the brake holding the vicinity of the outer edge part of the brake disc between a support plate and a scale mounting plate under pressure to form a base line brake mechanism and an arbitrary angle brake mechanism. CONSTITUTION:When a base line brake lever 71 is revolved in the direction on this side, a left screw 67 is revolved leftwardly by the actions of a main driving sector gear 69 and a passive sector gear 68 to be screwed in a brake shoe 65. Since the leading end part of the left screw 67 is in contact with the stopper screw 72 screwed in a support plate 51, the rear part of the brake shoe 65 is raised upwardly and shaken around a sector pin 64 and the front end part 65a of the brake shoe brings the brake disc 59 into contact with a fixed brake shoe 66 under pressure to stop the revolution of the brake disc 59 and a protraction disc 58. When an index level 74 is revolved in the direction on this side, the brake shoe 59 is brought into contact with the fixed brake shoe 82 under pressure by a leading end region 80a and a scale mounting plate 53 can be fixed at an arbitrary angle with respect to the protraction disc 58.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a brake device for setting the angle of a drafting head used in a universal parallel ruler.

[Prior Art] An example of a conventional drawing head will be described with reference to FIG. 3 of the attached drawings. In the figure, 0) is a drafting head. The drafting head (1) is formed of a support plate (2) connected to a freely parallel arm or carriage, and a scale mounting plate (3) pivotally connected to the support plate (2).
) is formed so that the scale mounting plate (3) can be fixed at any angle by operating a gripping part (4) integrally fixed to the scale.

Further, a protractor plate (5) and a ratchet wheel (6) connected to the protractor plate (5) are interposed between the support plate (2) and the scale mounting plate (3), and the protractor plate (5) is connected to the protractor plate (5). Brake mechanism (7) that can fix the plate (5) and ratchet wheel (6) to the support plate (2) and scale mounting plate (3), respectively.
8).

That is, the baseline brake lever (9) pivotally connected to the support plate (2)
) is rotated from the front side to the back side in FIG. 3, the brake piece Q+) screwed onto the rotation shaft (In) of the baseline brake lever (9) is lowered. The brake piece (I-shaped T head (lla) is loosely inserted into the guide groove (■) which is convex in cross section and is bored in the upper surface of the protractor board (5), and the guide groove (+2 is the protractor). Since the brake pieces 01) are arranged in an annular manner in the circumferential direction of the plate (5), the brake pieces 01) can be lowered to remove the support plate (2).
When the pressure contact between the and the protractor (5) is released, the grip part (4)
), the protractor plate (5) can be attached to the scale mounting plate (3).
It rotates as one. And the vernier 0 of the support plate (2)
The index marked → and the angle scale of the protractor (5) (not shown)
When the desired reference line angle is determined by and the reference line brake lever (9) is rotated from the back side of the page to the front side in FIG. (2), and the scale mounting plate (3) and the protractor plate (5) are fixed to the support plate (2).

Next, to rotate the scale mounting plate (3) to any angle with respect to the reference line determined by the above procedure, press the index lever (→ to the left in the figure) to rotate the scale mounting plate (3). The connecting pin (10) loosely inserted into the rotation shaft (Ic9) rotates counterclockwise using the expanded portion (b) of the middle u■ portion as a fulcrum.Then, the index claw operation plate ( Move the date to the right against the bias of the coil spring (casting).Then, the tip of the index claw operation plate (day (A) (shown in Figure 3) is moved by the ratchet wheel (6).
), the scale mounting plate (3) becomes freely rotatable with respect to the protractor (5), and when the index lever (Y) is released from the index claw operation plate (tip of the day ( b) is the pawl 0 of the ratchet wheel (6) again.
! 1) and the scale mounting plate (3) is fixed.

Therefore, the fixed angle by the above operation is the pawl G! of the ratchet wheel (6)! I) (2+)... When fixing the scale mounting plate (3) at an angle other than this fixed angle, press the index lever (B) and tighten the ratchet wheel (6). With the tip of the index claw operation plate (G) separated from the tip (A), rotate the index lever (Y) toward the front in the figure.

Then, the pin (A) engaged with the intermediate part of the index lever 04) is pressed, and the brake pad (To) on which the pin (A) is erected rotates, and the brake pad (C) is attached to the scale mounting plate. Since it is screwed into the rotation axis O→ of (3), it moves downward. By this movement, the thrust bearing (b) is clamped against the support plate (2), and the scale mounting plate (3) is fixed at an arbitrary angle to the support plate (2).

[Problems to be Solved by the Invention] Since the conventional brake device described above has a complicated structure, for example, the scale mounting plate ( 3) When rotating, the guide groove (+2) and the brake piece (11) may rub against each other and prevent smooth rotation, so high precision is required in processing and assembly.

Furthermore, since the brake piece (11) and the brake pad (1) are arranged relatively close to one rotational shaft, there is a problem in that the operating force required to obtain the desired braking force is large.

Therefore, a technical problem has arisen that needs to be solved in order to provide a braking device for a drafting head that improves braking force, reduces operating force, and facilitates processing and assembly to improve operability and productivity. The purpose of the present invention is to solve this problem.

[Means for Solving the Problems] The present invention has been proposed to achieve the above object, and is a drafting head attached to a carriage on a drawing board, in which a scale is attached to a support plate connected to the carriage. a reference line setting means for pivoting the mounting plate and the protractor on the same axis and fixing the protractor to the supporting plate at an arbitrary rotation angle; In the drafting head having arbitrary angle setting means fixed at It is an object of the present invention to provide a braking device for a drafting head, which is characterized in that a clamping brake is provided to form a baseline braking mechanism and an arbitrary angle braking mechanism.

[Operation] When the base line brake mechanism is braked, the brake provided on the support plate to be connected to the carriage or the arm clamps and brakes the vicinity of the outer edge of the brake disc integrally connected to the protractor. Fix the protractor to the support plate. Furthermore, when the baseline brake mechanism is operated to release the brake on the brake disc, the protractor becomes rotatable relative to the support plate.

Further, by operating the arbitrary angle brake mechanism, the brake provided on the scale mounting plate pinches the brake disc,
The scale mounting plate is fixed to the protractor. That is, the setting of the reference line and the setting of an arbitrary angle that allows the angle with respect to the reference line to be directly read are performed via one brake disc.

[Embodiment] Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2 of the attached drawings. In FIG. 1, (50) is a drafting head, (51) is a support plate connected to the carriage of a universal parallel ruler, (52) is a rotating shaft loosely fitted to the support plate (5I), ( 53) is a scale mounting plate coupled to the rotation shaft (52). A plate with a number of gripping parts (54) is fitted onto the upper part of the rotation shaft (52) and fixed with a nut (55), and a gripping part (56) is attached to the plate with a number of gripping parts (54) with a bolt (57). ) (5?)... is formed so that the scale mounting plate (53) can be rotated by being fixed.

A protractor board (58) is freely rotatably interposed between the support plate (51) and the scale mounting plate (53).
) is combined with a brake disc (59) formed of a thin metal plate and a ratchet wheel (60). a baseline brake mechanism (61) in which the brake disc (59) is formed to have a larger diameter than the protractor (58) and the ratchet wheel (60), and its outer edge is provided on the support plate (51);
Arbitrary angle brake device installed on scale mounting plate (53)
i ($2) to apply pressure and brake.

The brake (63) provided on the support plate (51) has a countersunk head (6
A brake shoe (65) is swingably supported by a center pin (64) having a
A fixed brake shoe (66,) provided on the support plate (51) opposite the tip of the brake shoe (66,)
5) to pinch the brake disc (59).

There is a left-hand thread (67) at the rear of the brake shoe (65).
are screwed together, and the head (67a) of the left-handed helical gear 67) is fitted into the center of rotation of the passive sector gear (6B), as shown in FIG. The active sector gear (6g) that drives the passive sector gear (68) is loosely fitted onto the support shaft (70) of the support plate (51), as shown in the figure and FIG. 7I) is installed protrudingly.

Therefore, when the baseline brake lever (71) is rotated toward the front in FIG. 1, the left-hand screw (67) is
rotates to the left and screws into the brake shoe (65).

Since the tip of the left-hand screw (67) is in contact with a stopper screw 72) screwed onto the support plate (51), the rear part of the brake shoe (65) is lifted upward and the center pin (64) is The brake shoe (66) swings as a fulcrum and the front end (65a) fixes the brake disc (59).
Brake disc (59) and protractor (58)
) to prevent rotation. Also, baseline brake lever (71)
When the brake disc (59) is rotated in the opposite direction to the above-mentioned direction, the clamping pressure of the brake disc (59) is released, and the scale mounting plate (53) and the protractor (58) are separated by rotating the grip (56). It can be rotated in one piece and fixed at any angle to set a reference line.

Inside the rotating wheel (52) is a hollow opening shaft (73).
is loosely inserted, and an index lever (74) is fitted onto the upper part of the eye opening movement shaft (73). The lower part of the opening shaft (73) protrudes from a hole (75) drilled in the scale mounting plate (53), and a main drive sector gear (76) is fixed thereto. A passive sector gear (77) meshing with the active sector gear (76).
) is fitted with a right-hand screw (79) of the brake (78), and when the index lever (74) is rotated toward the front, the right-hand screw (79) screwed into the scale mounting plate (53) is fitted. 79) protrudes upward, and the brake shoe (80
). Then, the brake shoe (80
) has a center pin (8) similar to the brake (63) mentioned above.
1) as a fulcrum, press the brake disc (59) against the fixed brake shoe (82) at the tip (Oh), and rotate the scale mounting plate (53) at any angle with respect to the protractor (58). It can be fixed with.

The brake disc (59) is made of a thin metal plate and has flexibility, so the fixed brake shoe (6G) (82
) Even if an error occurs in the distance between the brake disc (59) and the brake disc (59), the brake disc (59) bends during braking and absorbs the error, so there is no risk of affecting the braking force.

Further, a second index lever (83) is disposed above the index lever (74), and is connected to the connecting pin (I) in the same way as the index lever described in the conventional example.
Activate the index claw operation plate (day) via ff.

The index claw operation plate (18) is inserted into the guide groove (531) of the scale mounting plate (53) by penetrating the lower end of the opening movement shaft (73), and the tip part (18) is inserted into the guide groove (531) of the scale mounting plate (53). ) protrudes upward from the hole (53b) of the ratchet wheel (60), and screws it into the claws (84) (84)... of the ratchet wheel (60) to attach the scale mounting plate (53) at a predetermined angle to the protractor (
58).

Note that this invention should not be limited to the above-mentioned embodiment, and a link mechanism or the like may be used in place of the sector gear to transmit the brake operation, and the structure of the brake (63) (7B), the operation lever, etc. Various modifications can be made to the arrangement, etc., and the present invention naturally extends to those modifications.

[Effects of the Invention] As described in detail in the above-mentioned embodiment, the present invention is structured so that one brake disc is used in common as a braking member for the brake mechanism for setting the reference line and the brake mechanism for setting the arbitrary angle. was able to be simplified. Furthermore, since the structure is such that the outer edge of the brake disc is compressed, even if there is some error in assembly, the rotation of the protractor and scale mounting plate will not be hindered when the brake is released, making assembly work easier. This invention not only makes it easier, but also provides an extremely large braking force, improving stability and operability.

[Brief explanation of drawings]

1 and 2 show one embodiment of the present invention, FIG. 1 is a longitudinal cross-sectional view of the drafting head, and FIG. 2 is a partially cutaway plan view showing the active sector gear and passive sector gear of the baseline brake mechanism. , FIG. 3 is a longitudinal sectional view showing a conventional drafting head. (50)... Drafting head (51)...
...Support plate (52) ...Rotation shaft (53
)...Scale mounting plate (58)...Protractor plate (59)...Brake disc (60)...
...Ratchet wheel (61) (62)...
... Brake mechanism (63) (78) ... Brake (64) (81) ... Center pin (li5) (
80) Brake shoe (66) (82)
...Fixed brake shoe (6B) (7?)・
...Passive sector gear (69) (76) ...
... Main drive sector gear (71) ... Baseline brake lever (74) ... Index lever Figure 2 (71) ... Baseline brake lever

Claims (1)

[Claims] A drafting head attached to a carriage on a drawing board,
A scale mounting plate and a protractor are coaxially pivoted to a support plate connected to the carriage, and a reference line setting means for fixing the protractor to the support plate at an arbitrary rotation angle; In contrast, in a drafting head having an arbitrary angle setting means for fixing the scale mounting plate at an arbitrary angle, a brake disc that rotates integrally with the protractor is provided, and each of the support plate and the scale mounting plate is provided with a brake disc that rotates integrally with the protractor. A braking device for a drafting head, characterized in that a brake is provided for compressing the vicinity of the outer edge of the brake disc to form a baseline braking mechanism and an arbitrary angle braking mechanism.