JPH06174044A - Screw type cam mechanism having reference-position setting function - Google Patents

Abstract

PURPOSE: To simply set a roller at a reference position by moving a roller from a thread ridge of a first outer diameter to a thread ridge of a second outer diameter or reversely moving the roller by rotating a screw and abutting the roller to a means for restricting a roller movement by an urging means to determine a reference position. CONSTITUTION: A feed screw portion 12 of a lead drum 11 fixed to a shaft 10 has a first feed portion 14 having a first thread ridge of an outer diameter D1 and a second feed portion 16 having a second thread ridge of an outer diameter D2. A roller 22 having a flange 20 at one end is rotatably provided on a shaft 24 above the feed screw portion 12. When the shaft 10 is rotated in a direction of an arrow 28 in a state that the roller 22 is positioned at the first feed portion 14, the roller 22 is moved to a direction of an arrow 30. When the roller 22 arrives at a left end of the first feed portion 14, the flange 20 is guided by the screw of outer diameter D2 of the second feed portion 16 and the roller 22 rides on the thread ridge of outer diameter D2. When the shaft 24 is spaced-apart from the feed screw portion 12 and the roller 22 is urged to a left direction by an urging means 32, the roller 22 is abutted to a member 26 and is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw type cam mechanism capable of easily setting a roller at a reference position. INDUSTRIAL APPLICABILITY The present invention is suitable for use in opening and closing a switch (so-called limit switch) related to control of operation of a rotating device.

[0002]

2. Description of the Related Art A cam mechanism using a screw and a nut has been conventionally known. When such a cam mechanism is applied to the opening and closing of the limit switch that controls the operation of the rotating device, it is necessary to accurately set the moving distance (stroke) of the nut before opening and closing the switch. That is, it is necessary to accurately position the nut at the reference position of the screw. Moreover, in order to minimize the interruption of the operation of the device, it is important to move the nut to the reference position of the screw quickly. However, in the conventional cam mechanism, it is impossible to move the nut to the reference position without rotating the nut or the screw. Furthermore, it has not been possible to easily and accurately set the position of the nut in the circumferential direction.

[0003]

A control roller such as a limit switch can be accurately and quickly set to a reference position by an extremely simple mechanism.
Displacement of the roller by the first or second outer diameter solves the above-mentioned drawbacks of the conventional cam mechanism.

[0004]

According to the present invention, according to the present invention, (a) a first shaft having a different diameter is fitted to a rotatable first shaft.
And a screw provided with a screw thread having a second outer diameter, and (b) a flange engageable with the screw, which is rotatably provided on a second shaft arranged in parallel with the first shaft. A roller, (c) an 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) Second means for interlocking with the first means to move the second shaft away from the first shaft to disengage the flange from the screw; and (f) the second roller. Means for restricting axial movement of the roller, the roller moving from the first outer diameter thread to the second outer diameter thread when the screw is rotated in a first direction. , The second screw
When rotated in the direction, the roller moves from the thread of the second outer diameter to the thread of the first outer diameter, and the first and second threads are moved.
When the means of (3) is operated, the roller is brought into contact with the third means by the biasing means and becomes the 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 11 fixed to the shaft 10 includes a feed screw portion 12 and an end portion 18. The feed screw portion 12 has a first feed portion 14 having a first thread with an outer diameter D1 and a second feed portion 16 having a second thread with an outer diameter D2 (see FIG. 2). The feed screw portion 12 and the end portion 18 are made of, for example, a suitable synthetic resin and are usually integrally molded. The feed screw portion 12 fits with the shaft 10, and the fitting is released when the roller 22 is moved to the reference position, as described later.

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 includes the first and second feed portions 1.
4 and 16 can be engaged with the respective thread grooves. The member 26 is fixed to the shaft 24 and is moved upward by the movement of the roller 22, as will be described later, and a limit switch or the like (not shown).
To operate.

It is assumed that the roller 22 is at the position of the first feeding section 14 as shown in FIG. In this state, when the shaft 10 is rotated in the direction shown by the arrow 28, the roller 22 is moved by the arrow 30.
Move in the direction of. When the roller 22 reaches the left end of the first feeding portion 14, the flange 20 is guided by the screw having the outer diameter D2 of the second feeding portion, and as shown in FIG. 6, the roller 22 has the outer diameter D2.
Get on the screw thread. Therefore, the member 26 fixed to the shaft 24
Can also move upward and operate the limit switch.

The second feeding section 16 will be described in detail with reference to FIG. FIG. 2 is a cross-sectional view as seen from AA in FIG. As shown in FIG. 2, the screw of the second feeding portion 16 is
The outer diameter D2 is larger than the outer diameter D1 of the screw of the first feeding portion 14. The thread of the screw of the second feeding portion 16 is
The first inclined portion 31 is provided so that the flange 20 can move from the first feeding portion 14 to the second feeding portion 16. That is, when the roller 22 reaches the left end of the first feeding portion 14, it is guided by the first inclined portion 31 and rides on the screw thread 29 having the outer diameter D2. When the shaft 10 further rotates in the direction of the arrow 28 (FIG. 1), the roller 22 moves from the screw thread 29 having the outer diameter D2 to the second inclined portion 27 and approaches the shaft 10. When the shaft 10 further rotates in the direction of the arrow 28, the roller 22 transfers from the second inclined portion 27 to the first inclined portion 31, climbs again to the screw thread 29 having the outer diameter D2, and repeats this operation.

When the shaft 22 continues to rotate in the direction of the arrow 28 (see FIG. 1) when the roller 22 is positioned on the second feed portion 16 (see FIG. 6), the flange 20 moves from the second inclined portion 27 to the first inclined portion 27. The transition to the ramp 31 must be exact. Therefore, it is desirable to make the thread groove between the first and second inclined portions sufficiently deep. Incidentally, when the roller 22 moves from the second inclined portion 27 to the first inclined portion 31, the member 26 temporarily moves downward, but the state of the switch when the roller 22 first rides on the screw thread 29 is electrically retained. If the control circuit is designed to do so, there will be no problem.

When the shaft 22 is positioned in the second feed portion 16 shown in FIG. 6, the shaft 22 is rotated in the direction opposite to the direction shown by the arrow 28 (see FIG. 1), so that the roller 22 has a thread 29.
To the first feeding portion 14 via the first inclined portion 31.

By the way, the setting of the roller 22 to the reference position should be made with a simple structure and in the shortest possible time.
In the present invention, unlike the conventional example, the flange 20 can be 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. 5 and 6).

However, even if the roller 22 is moved leftward by the urging means 32, the roller 22 cannot be positioned at a predetermined position of the lead drum 11 (that is, it can be positioned at the reference position of the lead drum). Can not).

FIG. 3 is a schematic side view of the apparatus of 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 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. 3, the shaft 36 is rotated in the direction of arrow 41 and the arm 38 is moved in the direction of arrow 4.
The lever 34 is rotated in the direction of arrow 42 while being rotated in the direction of 4. Therefore, the shaft 24 is moved away from the shaft 10 by the rotation of the arm 38, the roller 22 is separated from the lead drum 11, and abuts against the member 26 by the biasing means 32. On the other hand, when the concave portion 34a of the lever 34 contacts the heart-shaped cam 40 and the lever 34 is further rotated in the direction of the arrow 42, the concave portion 34a of the lever 34 rotates the cam 40 and the cam 40 moves to the position shown in FIG. Becomes Cam 40 is shaft 1
Since it is pivotally supported on 0 and fixed to the lead drum 11, the lead drum 11 also rotates by the rotation of the cam 40. Therefore, if the position of the cam 40 shown in FIG. 4 is set to a predetermined position of the rotation angle of the lead drum 11 (that is, the reference position of the lead drum), the lever 34 is rotated in the direction of the arrow 42, so that the lead drum 11 is moved. It can be a predetermined position in the circumferential direction. Although it is not clear from the drawing,
As described above, until the roller 22 is separated from the lead drum 11 to the reference position, the lead drum 11 and the shaft 1
Remove the mating with 0.

Next, when the shaft 36 is rotated in the direction opposite to the arrow 41, the roll 22 is positioned at the reference position of the lead drum 11. FIG. 6 shows how the roll 22 moves to the reference position of the lead drum 11.

FIG. 7 is a view for explaining an example in which the screw type cam mechanism according to the present invention is applied to control of a limit switch. In FIG. 7, two screw type cam mechanisms shown in FIG. 1 etc. are connected in series. The left and right screw cam mechanisms are distinguished by reference numerals 99 and 100, respectively. Since the components of the screw type cam mechanisms 99 and 100 are exactly the same, the same numbers are used for the corresponding components and the right cam mechanism 100 is used.
The reference number of “” is attached with “′”.

The apparatus shown in FIG. 7 is suitable for use in a tubular actuator which is a drive source for pulling out or rewinding a window screen or the like. A case where the device of FIG. 7 is applied to a tubular actuator for pulling out a window screen will be described. First, it is necessary to accurately set the pull-out amount of the window screen.

As shown in FIG. 7, a screw type cam mechanism 100 is provided.
It is assumed that the roller 22 ′ of No. 22 is located in the middle of the lead drum 11 ′, and the roller 22 of the screw cam mechanism 99 is at the reference position. Next, when the shaft 10 is rotated in the direction of the arrow 50, the roller 22 moves from the first screw feeding portion 16 to the second screw feeding portion 14 (see FIG. 1) and moves rightward. On the other hand, the right roller 22 'also moves to the right. After rotating the shaft 10 a predetermined number of times (that is, corresponding to the amount of pulling out the window screen), the rotation of the shaft 10 is stopped and the roller 22 'is set to the reference position. That is, when the roller 22 moves from the reference position to the right side by a predetermined distance, the roller 22 'becomes the reference position, and conversely, when the roller 22' moves from the reference position to the left side by the predetermined distance, the roller 22 becomes the reference position. Therefore,
By controlling the switch that controls the drive motor at the reference position of the rollers 22 and 22 ', the exact amount of screen withdrawal can be specified.

In FIG. 7, limit switches (not shown) are arranged near the members 26 and 26 '.
However, the shaft 24 may be extended to the left and a new member for controlling the limit switch may be provided below the end portion 18.

[0020]

As described above, according to the present invention, the roller of the screw cam mechanism can be set to the reference position extremely easily and in a short time. Therefore, it is extremely convenient to apply to open / close control of limit switches and the like.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view seen from AA in FIG.

FIG. 3 is a diagram illustrating a reference position setting according to the present invention.

FIG. 4 is a diagram illustrating a reference position setting according to the present invention.

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

FIG. 6 is a side view of the device according to the present invention.

FIG. 7 is a diagram illustrating a usage example of the device according to the present invention.

[Explanation of symbols]

 10 Shaft 12 Feed Screw Part 14 First Feeding Part 16 Second Feeding Part 20 Flange 22 Roller 24 Shaft 32 Biasing Means 34 Lever 36 Shaft

Claims (3)

[Claims] 1. (a) A screw fitted to a rotatable first shaft and provided with threads of first and second outer diameters having different diameters, and (b) a flange engageable with the screw. A roller rotatably provided on a second shaft arranged parallel to the first shaft, and (c) a biasing means for biasing 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) interlocking with the first means so that the second shaft is connected to the first shaft.
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, When the screw is rotated in the first direction, the roller moves from the first outer diameter thread to the second outer diameter thread, and when the screw is rotated in the second direction, the roller moves to the second direction.
When the outer diameter screw thread is moved to the first outer diameter thread and the first and second means are operated, the roller is brought into contact with the third means by the urging means and becomes the reference position. A screw-type cam mechanism having a reference position setting function. 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. 2. A screw type cam 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 type cam mechanism having a reference position setting function according to claim 2.