JPH0685729B2 - Table lifting device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nut between a lifting table mounted on a fixed frame so as to be vertically movable via a straight guide and a fixed frame, while being fixed so as not to move vertically. The present invention relates to a table elevating device including a screw and a motor that rotationally drive a nut.

[0002]

2. Description of the Related Art Conventionally, as a method of raising and lowering an elevating table in a banquet hall of a hotel, a ryotei or a general household, or a retractable table elevating to a proper height from the floor, for example, FIG.
As shown in FIG. 2, there are a drive device 2 for raising and lowering the table 1 using a hydraulically driven cylinder, or a device using a motor driven screw and nut.

[0003]

Here, in the case of a hydraulic cylinder, since the smell of oil is extremely disliked in a banquet hall or a parlor of a general household, the seal portion of the hydraulic cylinder is completely sealed to prevent oil from leaking. However, for a long time, there was a drawback that the oil leaked by bleeding from the seal part. Also, in the case of a motor-driven screw / nut system, no oil is used, so there is no oil odor, but if the motor shuts off when the table hits the stopper and stops at the stroke end, the screw / nut will bite and this time. Even if you try to reverse the motor, there is a drawback that the motor will not rotate, but if you stop the motor before the screw and nut bite, the adhesion between the floor surface as a stopper and the table will be poor. Besides, if the elevating stroke is long, the height of the main body at the time of contraction becomes high, and the minimum height also becomes high, so it is necessary to dig the pit as much as the minimum height is lowered. In this case, since the height of the table body is higher than the underfloor dimension, there is a drawback that the pit must be dug correspondingly.

Therefore, an object of the present invention is to allow the motor to smoothly rotate in the reverse direction even if the motor shutoff is delayed after the table has stopped at the stroke end, and the adhesion between the floor surface as a stopper and the table. It is an object of the present invention to provide a table elevating / lowering device capable of significantly reducing the height of the entire device, even if the elevating stroke of the table is long.

[0005]

That is, according to the present invention, there is provided a table mounted on a fixed frame so as to be vertically movable while being positioned via a straight guide, and the straight guide is provided on one of the fixed frame and the table in parallel with the straight guide. And the screw rod mounted so as to be movable only in the axial direction against the urging force of the spring in a state where the rotation is blocked, and the screw rod and the screw with the vertical position being restricted to the other of the fixed frame and the table. In the table lifting device equipped with each of the nuts that are driven to rotate by the motor to move the table up and down while fitted, in the fitting position with the nut on the screw rod corresponding to the upper stroke end of the table,
A stopper is formed that abuts the nut in the direction of its rotation and blocks the rotation corresponding to the stroke end of the nut or more,
In addition, the table lifting device includes a control device that stops the movement of the screw rod by the motor when the screw rod moves in the axial direction by a predetermined distance against the biasing force of the spring. Further, in the present invention, in the table lifting device, the straight guide and the screw rod are of a multi-stage type capable of mutual movement, and the screw rod is screw-fitted to the screw rod also serving as a nut to expand and contract in the axial direction. The table lifting device has a stopper formed at the stroke end position of the stepped screw rod so as to prevent rotation corresponding to the stroke end of the screw rod that also functions as a nut by abutting each screw rod in the rotation direction.

[0006]

When the motor is driven to rotate in response to the ascent of the table at the table lowest position of the table elevating device constructed as described above, the nut is moved by the rotation of the nut by the motor and the table moves straight. Ascend along the guide. When the table reaches the ascending end, the nut abuts the stopper on the threaded rod in the circumferential direction to prevent the rotational drive. At this time, the motor is stopped by detecting the lock current of the motor or the operation of the limit switch. Can be located at the rising end.

Next, in this stopped state, that is, in the stopped state in which the nut contacts the stopper and the motor locks, the tightening force does not act between the nut and the screw rod, so the motor is driven in reverse. Then, the motor smoothly rotates to drive the nut to rotate, and the table moves downward, and at the time when the table reaches the lower end, for example, the floor surface, the nut rotates against the biasing force of the spring and rotates the screw rod. When the table is kept in close contact with the floor surface, the limit switch of the control device operates, for example, to stop the motor, so that the table keeps close contact with the floor surface and obstructs reverse rotation of the motor. It can be located at the lower end due to the biasing force of a spring. Moreover, in this case, in the case of a multi-step type in which the straight guide and the threaded rod can mutually move, the multi-stepped threaded rod comes into contact with the stopper in the rotation direction of each threaded rod at each stroke end position and the nut In order to prevent rotation of the threaded rod that also doubles as the stroke end, the stroke of the table is increased while the minimum height of the table is lowered.
When the table reaches the ascending end, the tightening force does not work between the nut and the screw rod, and when the table reaches the descending end, the table and the floor surface are in close contact and the motor is driven in the reverse direction. The table can be positioned at the lower end by the urging force of the spring without any hindrance.

[0008]

As a result, according to the present invention, even after the table stops at the stroke end, the motor can be smoothly rotated in the reverse direction even if the motor shuts off and the motor stops in the locked state. Even if the stroke of lifting and lowering the table is long, the height of the entire device can be significantly reduced while ensuring close contact with the floor.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the structure of one embodiment of the present invention will be described with reference to the drawings. In the fixed frame 4 mounted on the floor or in the pit 3, the table 6 alone or in the state where the tatami mat 35 is placed in a state of being positioned via the straight guides 5 in one or more stages, in this case two stages. It is mounted so that it can move up and down. That is, the square pipe upward guide 7 attached upward to the fixed frame 4 and the square pipe downward guide 8 attached downward to the table 6.
An intermediate guide 9 is provided between the upper and lower guides 7, 8
The linear bearing 10 attached to the intermediate guide 9 and the linear rail 11 attached to the intermediate guide 9 are slidable with each other and the slide amount is regulated via the stopper 12.

Further, in the spring receiver 29 fixed to the fixed frame 4, the main screw rod 14 forming the screw rod 13 in one step or a plurality of steps, in this case, two steps in parallel with the straight guide 5, is provided. Through a detent pin 31 and a spring 32 that are slidably fitted in a vertical groove 30 formed in the body 29, it is attached so as to be movable only in the axial direction against the biasing force of the spring 32 while being prevented from rotating. Also, the spring receiver 29 has a rotation stopper pin 31
Control device for stopping the motor 21 when the screw rod 14 moves against a biasing force of the spring 32 by a predetermined distance due to interference with the limit switch 33.
Further, a hollow cylindrical sub-screw bar 16 having a nut portion 15 screw-fitted to the main screw bar 14 at its lower end is attached to the main screw bar 14 so as to be vertically movable while rotating on the main screw bar 14. The upper end of the main screw rod 14 and the upper end of the nut portion 15 of the sub screw rod 16 have the sub screw rod 16 as shown by a skeleton in FIG.
The nut portion 15 of the
17 to prevent rotation beyond the stroke end of
Are formed.

On the other hand, the support 1 is provided below the downward guide 8.
8 is integrally mounted, and a cylindrical moving nut 19 that is screw-fitted to the sub screw rod 16 is rotatably mounted to the support 18 via a bearing 20 in a state in which the vertical position is regulated and moved. The nut 19 is rotatably mounted via an output shaft 22 of a motor 21 mounted on the support 18, timing pulleys 23 and 24, and a timing belt 25. Further, as shown by a skeleton in FIG. 7, the moving nut 19 abuts on both ends of the sub-threaded rod 16 and both ends of the moving nut 19 in the rotational direction to prevent the moving nut 19 from rotating beyond the stroke end. A stopper 26 is formed. Between the fixed frame 4 and the table 6, a cover 27 surrounding each of the drive-related devices is attached so as to be vertically slidable together with the table 6.

Next, the operation of this embodiment will be described.
When the motor 21 is rotationally driven in response to the ascent of the table 6 at the table 6 lowest height position of the table elevating device 28 thus configured, the motor 21 moves through the timing pulleys 23 and 24 / timing belt 25. As the nut 19 rotates, the moving nut 19 moves on the sub screw rod 16, and depending on the degree of friction, the sub screw rod 16 moves on the main screw rod 14 together with the nut portion 15, and the table 6 rises along the straight guide 5. In this way, when the moving nut 19 reaches the stroke end of the upper end of the sub screw rod 16 or the nut portion 15 of the sub screw rod 16 reaches the stroke end of the upper end of the main screw rod 14, the stopper 26 on the moving nut 19 moves to the upper end position of the sub screw rod 16. Circumferentially abuts the stopper 26 of the sub-threaded rod 16 or the stopper 17 on the nut portion 15 of the sub screw rod
Is abutted on the stopper 17 at the upper end position of the main screw rod 14 in the circumferential direction to prevent the rotational drive, and the rotation nut is not blocked.
Continues to rotate, and when the table 6 reaches the rising end, the stoppers 26 and 17 on both nuts 15 and 19 are brought into contact with the stoppers 26 and 17 on both screw rods 14 and 16 in the circumferential direction to rotate. The driving is blocked, and the motor 21 is stopped by the detection of the lock current of the motor 21 or the operation of the limit switch (not shown) at this time, and the table 6 can be positioned at the highest end.

Next, this stopped state, that is, both nuts 1
5, 19 are stoppers 26, 17 on both screw rods 14, 16.
When the motor 21 is stopped by contacting the
Since the tightening force does not operate between the nuts 15 and 19 and the screw rods 14 and 16, when the motor 21 is driven in the reverse direction, the motor 21 smoothly rotates, and in the same manner as when the motor is raised, Both nuts 15 and 19 are appropriately rotated according to the degree of friction to lower the table 6, and when the table 6 reaches the lower end, for example, the floor surface 34, the nut 15 resists the urging force of the spring 32. Then, the screw rod 14 is moved upward to rotate the screw rod 14 to make the contact between the table 6 and the floor surface 34 more reliable, and the limit switch 33, for example, of the control device is actuated to stop the motor 21 and the table 6 to the floor surface. It can be positioned at the lower end by the urging force of the spring 32 that secures close contact with the motor 34 and does not hinder the reverse rotation of the motor 21. Moreover, in this case,
When the straight guide 5 and the screw rod 13 are of a multi-stage type in which each can move, the multi-stage type screw rod 13 hits the stoppers 17 and 26 at the respective stroke end positions in the rotation direction of the screw rods 14 and 16. In order to prevent rotation of the threaded rod which also comes into contact with it and also serves as a nut, in this case, the rotation of the sub threaded rod 16 beyond the stroke end, the stroke of the table 6 is increased while the minimum height of the table 6 is lowered. When the nut reaches the rising end, nuts 1, 1
The tightening force does not work between 9 and the screw rods 14 and 16,
When the table 6 reaches the descending end, the table 6 can be positioned at the descending end by the biasing force of the spring 32 that secures the close contact between the table 6 and the floor surface 34 and does not hinder the reverse rotation of the motor 21. . As a result, after the table 6 stops at the stroke end, even if the motor 21 shuts off and the motor 21 stops in the locked state, the motor 21 can be smoothly rotated in the reverse direction and the floor surface 34 as a stopper can be used. Adhesion with the table 6 can be sufficiently ensured, and the height of the entire apparatus can be significantly reduced even if the lifting stroke of the table 6 is long.

[Brief description of drawings]

FIG. 1 is a cutaway front view showing a most lowered state of a table lifting device 28. FIG.

FIG. 2 is a view showing a spring receiver 29 portion as viewed in the direction of arrow A in FIG.

FIG. 3 is a cutaway front view showing a table lift device 28 in a most raised state.

FIG. 4 is a cutaway plan view of a table lifting device 28.

FIG. 5 is a partially cutaway front view showing a mounted state of the table lifting device 28.

FIG. 6 is a bottom view of the entire table 6 and its lifting device 28.

FIG. 7 is a detailed view showing a main part of a table lifting device by a skeleton.

FIG. 8 is a view showing a usage state of the table 6 and its lifting device 28.

FIG. 9 is a partially cutaway front view of a conventional table lifting device.

[Explanation of symbols]

 3 Pit 4 Fixed frame 5 Straight guide 6 Table 7 Upward guide 8 Downward guide 9 Intermediate guide 10 Linear bearing 11 Linear rail 12 Stopper 13 Screw rod 14 Main screw rod 15 Nut part 16 Sub screw rod 17 Stopper 18 Support 19 Moving nut 20 Bearing 21 Motor 22 Output shaft 23 Timing pulley 24 Timing pulley 25 Timing belt 26 Stopper 27 Cover 28 Table lifting device 29 Spring receiver 30 Vertical groove 31 Rotation stop pin 32 Spring 33 Limit switch 34 Floor surface 35 Tatami

Claims (2)

[Claims] 1. A table attached to a fixed frame so as to be vertically movable while being positioned through a straight guide, and a spring attached to one of the fixed frame and the table in a state in which the straight guide is parallel and rotation is prevented. A screw rod mounted so as to be movable only in the axial direction against the force and a vertically rotating position on the other of the fixed frame and the table, which is rotationally driven by a motor while being screw-fitted to the screw rod. In a table lifting device equipped with a nut that moves the table up and down, at the mating position with the nut on the threaded rod that corresponds to the upper stroke end of the table, contact the nut in the rotation direction and the stroke end of the nut. Corresponding to the above, a stopper to prevent rotation is formed, and the screw rod resists the urging force of the spring and moves in the axial direction. And a control device for stopping the movement of the screw rod by the motor when the table is moved by a predetermined distance. 2. A multi-step type screw rod in which a straight guide and a threaded rod are of a multi-step type capable of mutually moving, and the threaded rod is screw-fitted into a threaded rod also serving as a nut and expands and contracts in an axial direction. The table lifting device according to claim 1, wherein a stopper is formed at a stroke end position to prevent rotation corresponding to a stroke end of the screw rod that also functions as a nut by abutting each screw rod in a rotation direction. .