JPS62130414A - Limit position detection for electric elevating device - Google Patents

Abstract

PURPOSE:To surely detect the limit position of an elevating device by installing a spring in the vicinity of the limit position and detecting the excessive current of a motor, which is caused by compression of the spring. CONSTITUTION:In terms of an electric elevating device for cosmetic treatment, a nut 2 is fitted in a guide screw 1 which is rotated and driven by the motor M, and a slide pipe 4 is fitted thereon so that it can vertically move inside a cylinder 3 together with the nut 2. Due to the rotation of the motor M a cosmetic treatment unit installed on the upper end part of the slide pipe 4 is elevated. Springs 5 and 6 are installed in the vicinity of the upper and lower parts of the route of the nut 2 so as to align with the spide pipe 4, and the nut 2 is abutted on the springs 5 and 6 according as the pipe 4 ascends and descends and the springs are compressed. Thus the load of the motor M increases. By detecting the excessive current state at that time, such detection can be made that the elevating device reaches the limit positions in upper and lower parts.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a limit position detection method for an electric lifting device.

[Conventional technology and problems]

Currently, for example, in beauty and beauty equipment, a hairdressing and beauty treatment unit that combines processing functions such as perm, iron perm, hair dye, treatment, hair growth promotion, drying, etc., and a so-called cauldron are supported by an electric lifting device. Some have adjustable height.

However, in conventional electric lifting devices of this type, the upper and lower limit positions are detected by limit switches (microswitches), so at least two microswitches are required. There was a problem in that the external dimensions became larger due to the installation, and additional wiring was required.

The present invention was made in view of the above circumstances, and its purpose is to provide a limit position detection method that can reliably detect the limit position of a lifting device without using a microswitch.

[Means for solving problems]

In order to solve the above problems, the limit position detection method for an electric lifting device according to the present invention includes a spring that is compressed when the lifting device reaches near the limit position, and the motor voltage generated by compression of the spring is provided. The present invention is characterized in that it detects that the elevating device has reached a limit position by detecting an overcurrent.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the limit position detection method for an electric lifting device according to the present invention will be described below with reference to FIGS. 1 and 2.

Figure 1 shows an example of an electric lifting device for hairdressing equipment.
A nut 2 is attached to the lead screw 1 which is rotationally driven by a motor M.
is fitted into the nut 2, and a slide vibe 4 is fixed to the upper surface of the nut 2 so as to move up and down inside the cylinder 3 together with the nut 2. That is, when the lead screw 1 is rotationally driven by the motor M, the slide vibrator 4 together with the nut 2 moves upward or downward depending on the rotational direction of the motor M, and the hairdressing and beauty treatment unit attached to the upper end of the slide vibrator 4 (Fig. (not shown).

Springs 5 and 6 are provided concentrically with the slide vibe 4 near the upper end and the lower end of the stroke of the NAND 2, respectively. When the slide vibrator 4 moves up or down and the upper or lower surface of the nut 2 comes into contact with these springs 5 or 6 and starts to compress the springs, the load on the motor M increases, so the overcurrent condition can be eliminated. By detecting in an appropriate manner, the lifting device can detect whether the upper or lower lamination 1.
It is possible to detect that the target position has been reached.

The above-mentioned overcurrent can be absorbed by a circuit as shown in FIG. 2, for example. In this circuit, motor M
The current in the power supply system is detected by the current transformer CT, and when the output of the current transformer CT exceeds a predetermined value, the overcurrent detection circuit 21 supplies a signal to the motor control circuit 22. Then, the motor control circuit 22 supplies a stop signal to the motor drive circuit 23, so the motor M stops at its limit position. In addition,
Detection of overcurrent can be performed by appropriately utilizing known means such as a voltage drop caused by a resistor, a Hall element, etc. in addition to a current transformer. For example, a simpler configuration is
In the motor drive system, a comparator may be used to compare the voltage that changes according to the load current with the voltage corresponding to the overcurrent set value, and when the load current exceeds the set value, the comparator may output a motor stop signal. . Further, the springs do not necessarily need to be provided at the upper and lower limit positions as described above, but may be provided at either one or any other desired position.

〔Effect of the invention〕

According to the present invention, there is no need to use a microswitch to detect the limit position of the lifting device, no electric wire is required for this purpose, and the external dimensions can be reduced.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing the main structure of an example of an electric lifting device for explaining the limit position detection method of the present invention, and Fig. 2 shows an example of a circuit for detecting overcurrent of the motor. It is a block diagram. 5.6...Spring, 21...Overcurrent detection circuit, M...Motor. Patent applicant: Ohhiro Seisakusho Co., Ltd. Agent: Kama 1) Text 2 Figure 1 Figure 2

Claims (1)

[Claims] It is characterized by comprising a spring that is compressed when the lifting device reaches the vicinity of the limit position, and detecting the overcurrent of the motor caused by the compression of the spring to detect that the lifting device has reached the limit position. A method for detecting the limit position of an electric lifting device.