JPH04161398A - Index lever device of drawing head - Google Patents

Abstract

PURPOSE:To achieve lock/unlock/unlock/unlock retaining operations by thumb manipulation in a one-way direction by providing a part for guiding a pin in the rotary direction of a link arm in a guide hole and a bent part which extends in the longitudinal direction of a slit hole in the link arm and engaging the pin under an unlocked state. CONSTITUTION:An index lever device and a ratchet claw piece 20 interlocked to the former 20 are energized constantly by a coil spring so that the claw piece tip is engaged with the ratchets 36, 36... of a ratchet wheel 17. In a guide hole 37, a bent part 38 which engages a pin 28 of an index lever, if a ratchet claw piece 20 is disconnected with the ratchet wheel 17, is provided. The pin 28 is engaged with the bent part 38 by rotation of the index lever in the last stage of a pressing operation, an stops under an unlock retaining state, resisting a coil spring. In addition, if a locked state is to be restored, the index lever is rotated to such an extent that the pin 28 becomes separated from the bent part 38. As a result, the pin 28 is separated from the bent part 38 and moves in a reverse direction through the guide hole 37 by energization of the coil spring to be set in a locked state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an index lever device for a drafting head, and more particularly to an index lever device for a drafting head with improved operability.

[Prior Art] Conventionally, a drafting head mounted on a rail type or belt pulley type drafting machine has a configuration shown in FIG. 5 of the attached drawings. In the same figure, 1 is a drafting head, 2 is a grip, and 3 is a support plate connected to the shaft or arm of the drafting machine. A ratchet wheel 4 is formed in which ratchets are carved at predetermined angular intervals. 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 piece 7 that is pivotally attached to the back surface of the scale mounting plate 5, and when pressed toward the rotation center of the grip 2, the ratchet pawl piece 7 engages the ratchet wheel of the support plate 3. 4, and the scale mounting plate 5 can be rotated.

When the index lever 6 is released, the ratchet claw piece 7 engages 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 disc 9 fixed to the support plate 3 to fix the scale mounting plate 5 to the support plate 3. When fixing the scale mounting plate 5 at an arbitrary relative angle different from the angle set by the index lever 6, the ratchet claw piece 7 is moved from the ratchet wheel 4 by pressing the index lever 6 toward the center of the grip 2. Then, the scale mounting plate 5 is rotated to an arbitrary angle, and the arbitrary angle brake lever 8 is tightened and fixed by operation. During such operation, it is necessary to maintain the released state in which the ratchet claw piece 7 is separated from the ratchet wheel 4, and after pressing the index lever 6 (■) as shown in FIG. Lift the part 10 (■) and engage it with the inner wall surface of the grip 2 to maintain the released state. Further, the locking portion lO
When the index lever 6 is rotated downward, the engagement is released, and the index lever 6 is returned to its original state by the biasing means.

[Problems to be Solved by the Invention] When operating the above-described conventional index lever to maintain the released state, the index lever is pressed in the horizontal direction and then rotated to lift the front locking part. have to move. Therefore, the thumb of the hand holding the grip is required to perform the above-mentioned complicated operation, which is not easy to perform smoothly and poses a problem in operability.

Therefore, there are technical issues that need to be solved in order to make the release/hold operation smooth and easy and improve operability.
The present invention aims to solve this problem.

[Means for Solving the Problems] The present invention is proposed to achieve the above object, and is a drafting head attached to a carriage or an arm of a drafting machine, which includes a support plate connected to the carriage, etc. , a scale mounting plate pivotally connected to the support plate, and a ratchet wheel on the support plate side;
In a drafting head that is capable of fixing the scale mounting plate at a predetermined angle by engaging and disengaging the ratchet pawl provided on the scale mounting plate with an index lever, the intermediate portion of the link arm 23 is attached to the scale mounting plate 15. Pivotally attached,
One end of the link arm 23 is locked to the middle part of the ratchet claw piece 20, and the index lever 26 is pivotally attached to the other end, and the rotation of the link arm 23 is guided to the scale mounting plate 15. A guide hole 37 is provided, a pin 28 is erected at an intermediate portion of the index lever 26, and a long hole 29 drilled near one end portion of the link arm 23 is loosely inserted into the guide hole 37. Guy F
'The hole 37 is provided with a bent portion 38 that can lock the pin 28 when the index lever 26 is pressed, so that the engagement between the ratchet claw piece 20 and the ratchet wheel 17 can be locked in the released state. An object of the present invention is to provide an index lever device for a drafting head.

The ratchet pawl piece, which can be freely engaged and detached from the C-action collatchet wheel, and the index lever are connected via a rotatable link arm. When the index lever is pressed with the thumb of the hand holding the grip of the drafting head, 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 is exerted by a force that moves within the guide hole of the scale mounting plate through the elongated hole drilled in the link arm (the guide hole guides the pin in the direction of rotation of the link arm). and a bent part that extends in the longitudinal direction of the elongated hole of the link arm and can lock the pin when in the released state. The rotational fulcrum of the index lever l- is moved from the rotational fulcrum of the link arm itself to the axis provided at one end of the link arm (it rotates twice, the pin is locked in the bent part, and the index lever is in the released state). stop. Therefore,
Locking, releasing, and releasing/holding operations can be performed by a series of thumb movements in one direction.

[Embodiment] An embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 4 of the drawings. FIG. 1 shows the bottom surface of the drafting head 11 with the exterior force/XI- and the grip removed, and the second
The figure is a plan view. In FIG. 1, 12 is a mounting plate connected to the vertical carriage of the drawing machine, 13 is a support plate fixed to the mounting plate 12, and the axis of the scale mounting plate 15 is inserted into the circular center hole 14 shown in FIG. 16 is fitted loosely. The support plate 13 is provided with a concentric ratchet wheel 17, as shown in FIG. 18 is a brake disc fixed to the ratchet wheel 17, 19 is an arbitrary angle brake that presses the outer edge of the brake disc, and 20 is a ratchet pawl piece that interlocks with an index lever device to be described later.

Reference numeral 21 shown in FIG. 2 is an operating lever for the arbitrary angle brake 19, and 22 is an index lever device. The link arm 23 of the index lever device 22 has the side of the intermediate portion raised upward, and is further bent 90 degrees to form a bearing portion 24 which has an opening shape in side view, and a support shaft erected on the scale mounting plate 15 25 through which the bearing portion 24 is inserted and rotatably pivotally mounted. An index lever 26 is pivotally attached to the vicinity of one end by a shaft 27, and a pin 28 is provided protruding from an intermediate portion of the index lever 26, and the pin 28 is loosely fitted into a long hole 29 drilled in the link arm 23. do. The other end of the link arm 23 is bent downward and hangs downward from a hole 30 drilled in the scale mounting plate 15;
A locking piece 3 that engages with the middle part of the ratchet pawl piece 20
It is strongly formed. Reference numeral 32 denotes a coil spring, which is inserted between a cut-and-raised portion 33 provided on the link arm 23 and a post 34 erected on the scale mounting plate 15, so that the link arm 23 is Force clockwise.

As shown in FIG. 1, the support shaft 2 of the link arm 23
5 protrudes toward the back surface and serves as a pivot point for the ratchet claw piece 20. The ratchet claw piece 20 has a hole 8 in the middle part.
The locking piece 31 of the link arm 23 is loosely fitted into the long hole 35 in the shape of a letter 35, and the tip is always engaged with the ratchet 36, 36, and 36 of the ratchet wheel 17 by the urging force of the coil spring 32.
... is fitted. Further, a guide hole 37 is bored in the scale mounting plate 15 at a position corresponding to the pin 28 of the index lever 26 described above, and the pin 28 is connected to the link arm 2.
It passes through the long hole 29 of No. 3 and is loosely inserted into the guide hole 37. The guide hole 37 is opened in the rotational direction of the link arm 23 so that the pin 28 can slide when the index lever 26 is pressed, and when the ratchet claw piece 20 is detached from the ratchet wheel 17. Bent part 3 that can sometimes lock the pin 28 of the index lever 26
8 to form an L-shape. Therefore, when the index lever 26 is pressed, the pin 28 moves along the guide hole 37 to position A shown by the dotted line in FIG.
The tip of the scale 0 moves away from the ratchet wheel 17 and the scale mounting plate 15 is unlocked from the support plate 13.

Then, if the pressure on the index lever 26 is released,
The coil spring 32 is biased to return to the locked state shown in FIGS. 1 and 2. On the other hand, to maintain the released state, press the index lever 26 toward the center of the grip with the thumb of the hand holding the grip. Before this pressing operation, the index lever 26 rotates about the support shaft 25, which is the axis of rotation of the link arm 23 relative to the scale mounting plate 15.
The direction of movement of the pin 28 of the index lever 26 that applies rotational force to the link arm 23 is regulated by the end of the guide hole 37 of the scale mounting plate 15, which is opened in the rotation direction of the link arm 23. does not rotate any further, so in the latter stage of the pressing operation, the index lever 26 moves toward the shaft 2 near one end of the link arm 23.
7 in the direction shown by arrow B in FIG. This rotation causes the pin 28 to move toward the bending portion 3 as shown in FIG.
8, and the index lever 2B stops in the released and held state against the bias of the coil spring 32, as shown in FIG.

In order to return to the locked state, the index lever 26 is rotated counterclockwise in FIG. 2 to such an extent that the pin 28 leaves the bending part 38. At the same time, the guide hole 37 is moved in the opposite direction to the previous stage by the bias of the coil ring 32, and the index lever 26 and link arm 23 are returned to the locked state shown in FIGS. 1 and 2.

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

Note that this invention can be modified in various ways without departing from the spirit of the invention, and it goes without saying that this invention extends to such modifications.

[Effects of the Invention] Since the present invention is constructed as detailed in the above embodiment, locking/releasing and releasing/holding operations by the index lever can be performed by a unidirectional movement of the thumb; Operation has become extremely smooth and easy. Therefore, the workability of drawing is improved and work efficiency is improved, and the external force applied to each part of the drawing head during operation is reduced due to improved smoothness, and improvements in reliability and durability can be expected. This invention has various effects.

[Brief explanation of drawings]

1 to 4 show an embodiment of the present invention, FIG. 1 is a bottom view of the drafting head in a state where the ratchet pawl and the ratchet wheel are engaged, FIG. 2 is a plan view of the same, and FIG. FIG. 4 is a bottom view showing a state in which the index lever is locked after the engagement is released, and FIG. 4 is a plan view thereof. Figures 5 and 6 show a conventional example; Figure 5 is a front view showing a state in which the ratchet pawl and the ratchet wheel are engaged, and Figure 6 is a front view showing a state in which the index lever is locked after the engagement is released. It is a diagram. 11 Drafting head 13 Support plate 15 Scale mounting plate 17 Ratchet wheel 20 Ratchet claw piece 22 Index lever device 23 Link arm 26 Index lever 28 Pin 37 Guide hole 38 Bend part

Claims (1)

[Claims] A drafting head attached to the carriage or arm of a drafting machine, consisting of a support plate connected to the carriage, etc., and a scale mounting plate rotatably pivoted to the support plate. In a drafting head in which the scale mounting plate can be fixed at a predetermined angle by engaging and disengaging a ratchet wheel and a ratchet pawl provided on the scale mounting plate using an index lever, a link arm 23 is attached to the scale mounting plate 15. One end of the link arm 23 is locked to the middle of the ratchet claw piece 20, and the index lever 26 is pivoted to the other end. A guide hole 37 is provided to guide the rotation of the arm 23, a pin 28 is provided upright at the intermediate portion of the index lever 26, and a long hole 29 drilled near one end portion of the link arm 23 is loosely fitted into the pin 28. Loosely insert the guide hole 37 into the guide hole 37.
A drafting head characterized in that a bent part 38 is provided on the index lever 26 to lock the pin 28 when the index lever 26 is pressed, so that the engagement between the ratchet claw piece 20 and the ratchet wheel 17 can be locked in the released state. index lever device.