JPS61192424A - Screw-existence detecting adsorbing sleeve - Google Patents

Abstract

PURPOSE:To continuously detect a screw from a screw adsorbing position to an aimed screw fastening position by installing a pair of electrodes for electric conduction in continuation from the top-edge inner surface to the rear edge of an adsorbing sleeve. CONSTITUTION:A screw-existence detecting adsorbing sleeve body 2 is constituted of the upper and lower sleeves 14 and 13 molded from the insulative ceramics or the thermosetting plastic material and an upper and lower sleeve fastening nut 7 for fastening and fixing the both sleeves 14 and 13. The inside surface at the lower edge part and the surface groove part 12 of the lower sleeve 13 are applied with a pair of electrodes for electric conduction in symmetrical form in the lateral direction through the application of the electric-conductive paint or the metal vapor deposition treatment. A closed circuit is constituted by the contact of the head part of a screw 1 and the right and left electrodes 3 for conduction in pairs which are applied onto the surface and the inner surface at the lower edge part of the screw-existence detecting adsorbing sleeve 2.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a screw suction type screw tightening machine for use in an automatic machine equipped with a screw suction sleeve, and particularly to a screw tightening machine that is suitable for detecting the presence or absence of a screw after suctioning a screw. Regarding the suction sleeve.

BACKGROUND OF THE INVENTION The conventional method for detecting the presence or absence of a screw in a screw suction type screw tightening device is to separate and position the screws that are continuously supplied from a screw supply device one by one. A magnetic sensor built into and installed in the screw supply device at the screw head or screw bottom end.

A commonly used method is to detect the signal using a photoelectric switch or the like and process the signal in a control section.

However, according to this detection method, it is possible to detect the screw positioned at the positioning part of the screw supply device up to the time when the suction sleeve suctions the screw, but after that (after screw suction is completed, the screw is moved to the target position). , until screw tightening is complete)
It is impossible to detect the suction state of the screw. In particular, when a screw suction type screw tightening device is installed on an automatic machine such as a robot with high-speed movement, after screw suction, there is a risk of shock, inertial force, vibration during movement, or , due to the influence of fluctuations in adsorption pressure, etc. - If the screw falls during movement before reaching the target position, the screw tightening bit will time up or torque will increase on one part or object to be fastened such as a plate. It continued to idle until the end of the year, causing damage to and destruction of the objects to be fastened, and no consideration was given to protecting the objects to be fastened.

In addition, there is a method of detecting the presence or absence of a screw in a suction screw tightening device by using a vacuum sensor to detect the atmospheric pressure inside the suction pipe after the screw has been suctioned. It is difficult to handle and it is difficult to make the device more compact.

There are problems such as being expensive.

A related detection method of this type is Japanese Patent Publication No. 1701/1983, although the device structure and function are different.

In this case, similar to the conventional method of detecting the presence or absence of a screw, the method detects the presence or absence of a screw at a pre-specified position, and it is impossible to continuously detect the presence or absence of a screw to determine whether it has been reliably attracted to the target position. As with detection, no consideration was given to detection of falling objects after detection signal processing.

[Purpose of the invention]

An object of the present invention is to provide a thread presence/absence inspection suction sleeve that enables continuous detection of screws from a screw suction position to a screw tightening target position.

[Summary of the invention]

The suction sleeve with and without threads of the present invention picks up the screw body that is positioned to be supplied to the positioning section of the screw supply device.

A conductive coating agent or
Through metal vapor deposition, conductive electrodes are continuously applied from the inner surface of the tip of the suction sleeve to the rear end in pairs on the left and right sides of the sleeve, and in response to the suction signal from the screw tightening device body,
By applying a minute DC voltage to the pair of electrically conductive electrodes provided on the sleeve and adsorbing them, electrical The presence or absence of screw suction is detected by continuity.

[Embodiments of the invention]

Hereinafter, specific embodiments of the suction sleeve for detecting the presence or absence of a screw according to the present invention will be described in detail based on the drawings.

FIG. 1 shows a cross section of the suction sleeve for detecting the presence or absence of a screw according to this embodiment.

The main body of the suction sleeve for detecting the presence or absence of a screw is composed of an upper sleeve 14, a lower sleeve main body, and upper and lower sleeve fastening nuts for fastening and fixing these, which are molded from insulating ceramic or hardened plastic material.

A pair of electrically conductive electrodes 3 are provided symmetrically on the inner surface of the lower end portion of the lower sleeve unit (see FIG. 2) and on the surface groove portion 12 using a coating agent or a metal vapor deposition process.

This conduction electrode 3 is in contact with a secondary signal transmission contact 5 provided at the upper end of the lower sleeve.

Further, the upper signal transmission contact 9a provided on the upper sleeve is connected to the child signal transmission contact 5 by rotating and fastening the upper and lower sleeve fastening nuts 7, and the lower sleeve 1 and 2 are connected to each other. The upper sleeve 14 becomes electrically conductive. The upper signal transmission probe point 9a has a structure in which the contact pressure is adjusted by the spring pressure of the spring 8 so that an appropriate contact state with the child signal transmission contact 5 can be obtained.

In addition, in order to maintain airtightness during screw suction, the lower sleeve 14
An elastic O-ring 6 is provided on the bottom surface of the .

By tightening the upper and lower sleeve fastening nuts 7, the structure is such that optimum airtightness can be obtained.

Further, a male threaded portion having the same diameter is provided on the upper surface of the upper sleeve 14 so that it can be fastened and fixed to the male threaded portion at the lower end of the suction pipe 11 on the screw tightening device main body side.

It becomes functionally effective by fastening and fixing the suction sleeve main body-2- for detecting the presence or absence of a screw.

Next, the detailed operation of the screw presence/absence detection suction sleeve of this embodiment will be explained with reference to FIGS. 1 and 3. ' The screw tightening control device 15, which has been given a signal from the automatic machine control device 16, operates the vacuum generator 19 and tightens a small amount of light between the pair of upper signal transmission contacts 9a and 9b provided mainly on the screw presence/absence detection suction sleeve. A DC voltage is applied, and the suction pipe 11 is lowered by the lifting mechanism (see Fig. 3) of the screw tightening device main body 18, the screw 1 is suctioned and held on the inner surface of the lower end of the screw presence detection suction sleeve 2, and the suction pipe is moved again. Raise 11. At this time, a closed circuit is constructed by contacting the head of the screw 1 with a pair of left and right conductive electrodes 3 provided on the inner surface and surface of the lower end of the screw presence/absence detection adsorption sleeve -3.

This circuit remains a closed circuit until the suction-held screw 1 is fastened to an object to be fastened or the screw falls due to movement of an automatic machine, and becomes an open circuit when no screw is present. By distinguishing between these two circuit sections and processing the signals,
Determine the presence or absence of screws. FIG. 2 shows the screw suction sleeve main body and the signal processing system set in the screw tightening device main body 18 mounted on the automatic machine 17.

Next, with reference to FIG. 4, an example of a signal processing flow when detecting the presence or absence of a screw in the suction sleeve for detecting the presence or absence of a screw according to this embodiment will be explained.

Screw suction 41 and screw tightening 45 indicate operations of the screw tightening device body, and positioning 43 indicates operations of an automatic machine. Does the suction sleeve with and without screws according to this example have continuity? It plays a role of outputting a signal as data for the judgment processing of 42 and 44. At this time, if it is determined that there is no screw, error processing 46 is executed.

According to this embodiment, it is possible to continuously detect the screw presence/absence state after screw suction. Even if a screw falls due to vibration during movement or fluctuations in suction pressure before the automatic machine reaches the screw tightening target position, appropriate measures can be taken immediately, which was impossible with conventional detection methods. It is possible to prevent damage to the object to be fastened due to idling of the screw tightening bit.

Further, by integrating the automatic machine and the control device for the screw tightening device, there are excellent effects such as miniaturization. In addition, 4 in the figure is a screw tightening bit.

1o is a pipe, and 12 is a surface groove.

〔Effect of the invention〕

According to the present invention, the presence or absence of a screw after screw suction can be continuously detected.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the suction sleeve for detecting the presence or absence of a screw, FIG. 2 is a bottom view of the suction sleeve for detecting the presence or absence of a screw, FIG. 3 is a signal processing system diagram, and FIG. 4 is a signal processing flowchart. 3...Continuity electrode, 4...Screw tightening bit, 12.
...Surface groove, 13-...Lower sleeve.

Claims (1)

[Claims] 1. In a suction type screw tightening machine that automatically performs the work from suction to tightening of a screw that has been positioned in advance at a suction position, the screw tightening machine can reliably perform operations from the screw suction machine to reaching the screw tightening point. In order to continuously detect that the screw is being attracted, a pair of conductive electrodes/contacts are placed symmetrically on the screw suction sleeve to the tip inner surface, surface groove, and rear end connection part of the screw suction sleeve. Confirm the screw adsorption state by applying a microvoltage to the conductive electrode part, which is continuously provided, and check the screw adsorption state by electrical continuity through the conductive electrode provided on the inner surface of the tip of the suction sleeve and the screw head after adsorption. A suction sleeve that detects the presence or absence of a screw.