JPH082713B2 - Indexing lever device for drafting head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drawing head index lever device, and more particularly to a drawing head index lever device with improved operability.

[Prior Art] Conventionally, a drafting head mounted on a rail-type or belt-pulley drafting machine has a configuration shown in Fig. 5 of the attached drawing. In the figure, 1 is a drafting head, 2 is a grip, 3 is a support plate for connecting to a carriage or arm of a drafting machine, and a pivotal attachment portion of the grip 2 is formed in a circular shape, and an outer periphery of the attachment portion is formed. The ratchet wheel 4 is formed by engraving the ratchet at a predetermined angular interval. 5
Is a scale mounting plate that rotates integrally with the grip 2, and 6 is an index lever provided on the scale mounting plate 5. The index lever 6 is connected to a ratchet pawl 7 pivotally mounted on the back surface of the scale mounting plate 5, and when the index pawl 7 is pressed toward the center of rotation of the grip 2, the ratchet pawl 7 is attached to the ratchet wheel of the support plate 3. 4, the scale mounting plate 5 can be rotated.
When the pressing of the index lever 6 is released, the ratchet pawl 7 meshes with the ratchet wheel 4 by a biasing means such as a spring (not shown), and the scale mounting plate 5
Is fixed to the support plate 3 at a predetermined angle. Reference numeral 8 denotes an arbitrary-angle brake lever, which clamps the brake disk 9 fixed to the support plate 3 to fix the scale mounting plate 5 to the support plate 3. When the scale mounting plate 5 is fixed at an arbitrary relative angle different from the angle setting by the index lever 6, the ratchet claw piece 7 is pressed by the pressing operation of the index lever 6 toward the center of the grip 2. The wheel is removed from the wheel 4, and the scale mounting plate 5 is rotated to an arbitrary angle and fixed by tightening the brake lever 8 at the arbitrary angle. At the time of such an operation, it is necessary to maintain the released state in which the ratchet pawl 7 is separated from the ratchet wheel 4, and after pressing the index lever 6 () as shown in FIG. The stopper 10 is lifted () and engaged with the inner wall surface of the grip 2 to hold the released state. Further, when the locking portion 10 is rotated downward, the engagement is released, and the index lever 6 is returned to the original state by the urging means.

[Problems to be Solved by the Invention] When the above-mentioned conventional index lever is operated to maintain the released state, the index lever should be pushed in the horizontal direction and the front locking portion should be raised. Must be turned to. For this reason, the complicated operation described above is required for the thumb holding the grip, and it is not easy to perform smoothly, and there is a problem in operability.

Therefore, there arises a technical problem to be solved in order to facilitate the releasing and holding operation smoothly and improve the operability, and an object of the present invention is to solve the problem.

[Means for Solving the Problems] The present invention is proposed in order to achieve the above-mentioned object, and is a drafting head attached to a carriage or an arm of a drafting machine, and a support plate connected to the carriage or the like. , A scale mounting plate pivotally attached to the support plate so that the ratchet wheel on the support plate side and the ratchet pawl provided on the scale mounting plate are engaged and disengaged by an index lever. , In the drawing head that can fix the scale mounting plate at a predetermined angle,
The middle part of the link arm 23 is pivotally attached to the scale mounting plate 15,
One end of the link arm 23 is locked to an intermediate portion of the ratchet claw piece 20, an index lever 26 is pivotally attached to the other end portion, and the link arm is attached to the scale mounting plate 15.
A guide hole 37 for guiding the rotation of 23 is provided, and a pin 28 is erected at an intermediate portion of the index lever 26 so that a link arm is formed.
A long hole 29 opened near one end of 23 is loosely fitted into the guide hole 37, and the pin 28 can be locked in the guide hole 37 when the index lever 26 is pressed. A portion 38 is provided, and the engagement between the ratchet pawl 20 and the ratchet wheel 17 is released by pressing the index lever, and the pin 28 is engaged with the bending portion 38 to maintain the released state. An index lever device for a drafting head having the above-mentioned configuration is provided.

[Operation] The ratchet pawl, which can be engaged with and disengaged from the ratchet wheel, and the index lever are connected via a rotatable link arm. When the thumb of the hand holding the grip of the drawing head presses the index lever, the link arm rotates and the engagement between the ratchet pawl and the ratchet wheel is released. At this time, the pin protruding from the index lever moves in the guide hole of the scale mounting plate through the long hole opened in the link arm, and the guide hole guides the pin in the rotating direction of the link arm. And a bent portion that extends in the longitudinal direction of the elongated hole of the link arm and can lock the pin in the released state. When the index lever is further rotated from the released state, the index lever is rotated. The fulcrum pivots about a shaft provided at one end of the link arm from the pivotal fulcrum of the link arm itself, the pin is locked in the bending portion, and the index lever stops in the released state. Therefore, the locking, releasing, and releasing holding operations can be performed by a series of movements of the thumb in one direction.

[Embodiment] An embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 4. FIG. 1 shows the bottom surface of the drawing head 11 with the exterior cover and grip removed, and FIG. 2 is a plan view. In FIG. 1, 12 is a mounting plate connected to a carriage of a drawing machine, 13 is a support plate fixed to the mounting plate 12, and a scale mounting plate 15 is provided in a circular center hole 14 shown in FIG.
The shaft 16 is loosely fitted. As shown in FIG. 1, the support plate 13 is provided with a concentric ratchet wheel 17. 18
Is a brake disc fixed to the ratchet wheel 17, 19 is an arbitrary angle brake that clamps the outer edge of the brake disc, and 20 is a ratchet pawl that is interlocked with an index lever device described later.

Reference numeral 21 shown in FIG. 2 is an operating lever of the arbitrary angle brake 19, and 22 is an index lever device. The link arm 23 of the index lever device 22 has a bearing portion that is U-shaped in side view by raising the side of the intermediate portion upward and further bending it by 90 degrees.
24 is formed, and the bearing portion 24 is inserted into a support shaft 25 provided upright on the scale mounting plate 15 so as to be pivotally attached. Then, the index lever 26 is pivotally attached to the vicinity of one end by a shaft 27, and a pin 28 is projectingly provided at an intermediate portion of the index lever 26, and the pin 28 is formed in a long hole 29 opened in the link arm 23. Fit loosely. The other end of the link arm 23 is
A locking piece 31 is formed which is bent downward and hangs downward from a hole 30 opened in the scale mounting plate 15 to engage with an intermediate portion of the ratchet claw piece 20. Reference numeral 32 is a coil spring, which is interposed between a cut-and-raised portion 33 provided on the link arm 23 and a post 34 provided upright on the scale mounting plate 15, so that the link arm 23 is counterclockwise in FIG. Bias in the direction.

As shown in FIG. 1, a support shaft 25 for the link arm 23.
Is a fulcrum of rotation of the ratchet claw piece 20 protruding to the back surface. The ratchet claw piece 20 has a locking piece 31 of the link arm 23 loosely fitted in an 8-shaped elongated hole 35 opened in the middle part, and the tip of the ratchet wheel 17 is always attached to the ratchet wheel 17 by urging the coil spring 32. It fits in 36,36 .... or,
A guide hole 37 is opened at the position of the scale mounting plate 15 corresponding to the pin 28 of the index lever 26 described above, and the pin 28
Is inserted into the guide hole 37 through the long hole 29 of the link arm 23. The guide hole 37 is provided with the index lever 26.
The pin 28 of the index lever 26 is opened substantially in the rotational direction of the link arm 23 so that the pin 28 can be slid along with the pressing operation of the index lever 26 and the ratchet pawl 20 is separated from the ratchet wheel 17. A bending portion 38 capable of locking 28 is provided to form an L shape. Therefore, when the index lever 26 is pressed, the pin 28 moves to the position A shown by the dotted line in FIG. 3 along the guide hole 37, and the tip end of the ratchet pawl 20 is rotated by the rotation of the link arm 23. The scale 17 is released from the wheel 17 and the locking of the scale mounting plate 15 with respect to the support plate 13 is released. When the pressing of the index lever 26 is released, the coil spring 32 is urged to return to the locked state shown in FIGS. On the other hand, when maintaining the released state, the thumb of the hand holding the grip pushes the index lever 26 toward the center of the grip. Before the pressing operation, the index lever 26 moves the scale mounting plate 15 of the link arm 23.
The scale 28 has a pin 28 of an index lever 26, which rotates about a support shaft 25 serving as a rotation axis for the link arm 23, which applies a rotational force to the link arm 23, in a rotation direction of the link arm 23. Since the movement direction is restricted by the end of the guide hole 37 of the mounting plate 15, the link arm 23 does not rotate any more. Therefore, in the latter stage of the pressing operation, the index lever 26 is centered on the shaft 27 near one end of the link arm 23. To rotate in the direction shown by arrow B in FIG. By this rotation, the pin 28 is locked to the bending portion 38 as shown in FIG. 3, and the index lever 26 is stopped in the released holding state against the bias of the coil spring 32 as shown in FIG. To do.

In order to return to the locked state, the index lever 26 is rotated in the counterclockwise direction in FIG.
At the same time as being separated from 38, the guide hole 37 is moved in the direction opposite to the previous stage by the bias of the coil pull 32, and the index lever 26 and the link arm 23 are returned to the locked state shown in FIGS. 1 and 2. It will be.

In this way, the locking and releasing can be performed by operating the index lever 26 in one direction.

The present invention can be variously modified without departing from the spirit of the present invention, and it goes without saying that the present invention extends to the modified version.

[Effect of the Invention] Since the present invention is configured as described in detail in the above-mentioned one embodiment, it is achieved that the lock / release and the release holding operation by the index lever are one-way operation of the thumb. , Operation became extremely smooth and easy. Therefore, the workability of drawing is improved and the work efficiency is improved, and the improvement of smoothness also reduces the external force applied to each part of the drawing head during the operation, which can be expected to improve the reliability and durability. It is an invention that produces various effects.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention. FIG. 1 is a bottom view of a drawing head in a state where a ratchet pawl and a ratchet wheel are in mesh, FIG. 2 is a plan view of the same, and FIG. Is a bottom view showing a state in which the meshing is released and the index lever is locked, and FIG. 4 is a plan view of the same. FIGS. 5 and 6 show a conventional example, FIG. 5 is a front view showing a state where the ratchet pawl and the ratchet wheel are in mesh, and FIG. 6 is a state in which the mesh is released and the index lever is locked. It is a front view shown. 11 …… Drafting head 13 …… Support plate 15 …… Scale mounting plate 17 …… Ratchet wheel 20 …… Ratchet pawl 22 …… Index lever device 23 …… Link arm 26 …… Index lever 28 …… Pin 37 …… Guide hole 38 …… Refraction part

Claims (1)

[Claims] 1. A drafting head mounted on a carriage or an arm of a drafting machine, comprising: a support plate connected to the carriage or the like; and a scale mounting plate pivotally attached to the support plate. In a drafting head in which the ratchet wheel on the side of the supporting plate and the ratchet pawl provided on the scale mounting plate are engaged and disengaged by an index lever, the scale mounting plate can be fixed at a predetermined angle. The link arm 23 is pivotally attached to the intermediate portion of the link arm 23, one end portion of the link arm 23 is locked to the intermediate portion of the ratchet pawl piece 20, and the index lever 26 is pivotally attached to the other end portion of the link arm 23. A guide hole 37 for guiding the rotation of the link arm 23 is provided in the plate 15, and a pin 28 is erected at an intermediate portion of the index lever 26 to open the link arm 23 near one end portion thereof. The elongated hole 29 is loosely fitted and inserted into the guide hole 37. Further, the guide hole 37 is provided with a bending portion 38 capable of locking the pin 28 when the index lever 26 is pressed. The engagement between the ratchet claw piece 20 and the ratchet wheel 17 is released by pressing, and the pin 28 is configured to be engaged with the bending portion 38 to hold the released state. Indexing lever device for drafting head.