JPH05118403A - Screw mechanism having reference-position setting function - Google Patents

Abstract

PURPOSE: To set and to change position of roller easily. CONSTITUTION: The screw mechanism has a screw 12 engaged with a rotatable first shaft 10, a roller 22 that has a flange 20 engage-able with the screw and is rotatably engaged with a second shaft 24 being parallel to the first shaft, a force means 32 for forcing the roller 22 to a determined direction on the second shaft 24, a first means for setting rotation angle of the screw in a determined value, a second means that is co-interlocked with the first means, departs the second shaft 24 away from the first shaft 10 and functions for releasing engagement of the flange and the screw, a third means for limiting the movement of the roller on the second shaft. The screw mechanism has the standard position setting functions by the manner of the position of the roller abutting to the third means by the force means being used as the standard position while the first and the second means are actuated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw mechanism having a reference position setting function for easily setting a roller at a reference position.

[0002]

2. Description of the Related Art A screw mechanism for rotating a screw to change the position of a nut and controlling an external device is known. However, with this type of screw mechanism, it is impossible to move the nut to the reference position without rotating the screw or the nut.

[0003]

It is an object of the present invention to move a member that moves by rotation of a screw to a reference position of the screw by a very simple operation.

[0004]

According to the present invention, (a) a screw fitted to a rotatable first shaft and (b) a flange engageable with the screw are provided. A roller rotatably provided on a second shaft arranged in parallel with the first shaft;
(c) urging means for urging the roller in a fixed direction on the second shaft, (d) first means for setting the rotation angle of the screw to a predetermined value, and (e) the first Means for moving the second shaft away from the first shaft to disengage the flange from the screw, and (f) on the second shaft of the roller. A third means for restricting movement, the first
And a screw mechanism having a reference position setting function, characterized in that, when the second means is operated, the biasing means causes the roller to come into contact with the third means to become a reference position.

[0005]

Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, the lead drum (screw) 11 fitted to the shaft 10 includes a feed screw portion 12 and an end portion 18. The feed screw portion 12 and the end portion 18 are made of, for example, a suitable synthetic resin and are usually integrally molded.

A roller 22 having a flange 20 at one end is rotatably provided on a shaft 24 above the feed screw portion 12 (in the drawing), and the flange 20 is engageable with the thread groove of the feed screw portion 12. .. The member 26 is fixed to the shaft 24 and serves to prevent the roller 22 from moving to the left and set the roller 22 to the reference position of the lead drum 11, as described later.

It is assumed that the roller 22 is in the position shown in FIG. In this state, when the shaft 10 rotates in the direction shown by the arrow 28, the roller 22 moves in the direction of the arrow 30, and when the shaft 10 rotates in the direction opposite to the arrow 28, the roller 22 moves in the direction opposite to the arrow 30.

By the way, there are cases where it is desired to quickly set the roller 22 to the reference position (predetermined position) of the lead drum. According to the present invention, the flange 20 can be easily separated from the feed screw portion 12. That is, when the shaft 24 is moved away from the feed screw portion 12 and the roller 22 is pushed leftward by the urging means 32, the roller 22 moves on the shaft 24 and comes into contact with the member 26 and stops. After that, if you return the shaft 24 to its original state,
The roller 22 is located at a predetermined position on the shaft 24 (see FIGS. 4 and 5).

However, even if the roller 22 is simply moved to the position shown in FIG. 4 by the biasing means 32, the roller 22 cannot be set to a predetermined position on the lead drum 11 (ie, the reference position of the lead drum). According to the invention, the roller 2
2 can be accurately set at a predetermined position on the lead drum 11.

FIG. 2 is a schematic side view of the apparatus shown in FIG. 1 as viewed from the left. The lever 34 is fixed to a shaft (hexagonal shaft) 36. The shaft 36 is rotatable but its axial position is fixed. The arm 38 is fixed to the shafts 36 and 24.
On the other hand, although it is not clear from the drawing, the heart-shaped cam 40 is fixed to the lead drum 11. Actually, cam 4
It is desirable to integrally mold the lead drum and the lead drum. Of course,
Since it suffices that the lead drum 11 be interlocked with the rotation of the cam 40, they may be simply fitted together.

In order to separate the roller 22 from the lead drum 11 and move it to the reference position, as shown in FIG. 2, the shaft 36 is rotated in the direction of arrow 41, and the lever 34 is moved in the direction of arrow 4.
Rotate in the direction of 2. Therefore, the recess 34 of the lever 34
When a comes into contact with the heart-shaped cam 40 and the shaft 36 is further rotated in the direction of the arrow 41, the cam 40 is rotated by the recess 34a of the lever 34, and the cam 40 comes to the position shown in FIG.
Since the cam 40 is rotatably supported by the shaft 10 and fixed to the lead drum 11, the rotation of the cam 40 also rotates the lead drum 11. Therefore, if the position of the cam 40 shown in FIG. 4 is set as the reference position in the rotation direction of the lead drum 11, the lead drum 11 can be set to the above-mentioned reference position by rotating the lever 34 in the direction of the arrow 42. I can.

[0012]

As described above, according to the present invention, the roller of the screw mechanism can be set to the reference position very easily and with one touch.

[Brief description of drawings]

1 is a side view of an apparatus according to the present invention.

2 is a view of the device of FIG. 1 as viewed from the left side of FIG.

3 is a diagram of the device of FIG. 1 viewed from the left side of FIG.

FIG. 4 is a side view of the device according to the present invention.

FIG. 5 is a side view of the device according to the present invention.

[Explanation of symbols]

 10 Shaft 12 Feed Screw Part 20 Flange 22 Roller 24 Shaft 32 Energizing Means 34 Lever 36 Shaft 38 Arm

Claims (3)

[Claims] Claim: What is claimed is: 1. (a) a screw fitted to a rotatable first shaft, and (b) a second screw which has a flange engageable with the screw and is arranged parallel to the first shaft. A roller rotatably provided on the shaft; (c) an urging means for urging the roller in a fixed direction on the second shaft; and (d) a rotation angle of the screw set to a predetermined value. 1 means, and (e) the second means is interlocked with the first means, and the second shaft is connected to the first means.
A second means for disengaging the flange from the screw and further away from the axis of the roller, and (f) third means for limiting movement of the roller on the second axis, A screw mechanism having a reference position setting function, characterized in that when the first and second means are operated, the biasing means causes the roller to come into contact with the third means to become a reference position. 2. The first means comprises: (a) a heart-shaped cam pivotally supported by the first shaft and fixed to the screw; and (b) fixed to a rotatable third shaft. A screw mechanism having a reference position setting function according to claim 1, further comprising: a lever that abuts on the cam and sets a rotation angle of the cam to a predetermined value. 3. The second means is fixed to the second and third shafts, and the second shaft is moved away from the first shaft by rotation of the third shaft. A screw mechanism having a reference position setting function according to claim 2.