JPH0111400Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial field of application This invention is used to tighten screws with extremely long neck lengths compared to the shaft diameter. This invention relates to a screw tightening machine that only tightens screws.

Configuration of conventional example and its problems A conventional screw tightening machine is shown in Fig. 1. 1 is an electric screwdriver that is a rotational drive source, and includes universal joints 2a, 2b, an intermediate shaft portion 3, and a drive shaft 4.
Bit 5 is connected via. Reference numeral 6 denotes a Y pipe, which holds the screw 8 which is fed by air through a hose 7 from a screw supply device (not shown).
Reference numeral 9 denotes an air cylinder, which is connected to a bracket 11 that is slidable along a slide shaft 10.
The air cylinder 9 is held by a plate 12 attached to a bracket 11 and a plate 15 attached to a bracket 14 which is slidable along a slide shaft 10 in conjunction with the movement of the air cylinder 9 via a rod 13. The screw tightening head section consisting of the electric screwdriver 1 to the Y pipe 6 is raised and lowered. Further, 16 and 17 are stoppers for the brackets 11 and 14, respectively, and set the amount of descent of the screw tightening head. 18 is a member to be fastened, and 19 is a screw hole member.

Conventional screw tightening machines configured as described above have automatic screw feeding and automatic When tightening, there are problems in passing the screw through the Y pipe 6 and hose 7 and in holding the screw in the Y pipe 6. For this reason,
The feeding and tightening of screws into the screw holes are separate processes, and the screws are inserted into the screw holes in advance and then tightened. Therefore, in the screw tightening process, if the screw is inserted in a bad position in the previous process,
There was a problem in that the screw could not be tightened because the bit 5 and the screw were not properly engaged.

Purpose of the invention The present invention solves the above-mentioned drawbacks, and enables screw tightening by accurately engaging a bit and a screw.

Structure of the invention The present invention includes a screw regulating member having a regulating hole at one end that can be fitted with the head of the screw to regulate the posture of the screw, and a tapered part formed to guide the screw into the regulating hole; A first spring biased to weaken the contact force when the head of the screw installed in a predetermined hole abuts the tapered portion, and a biasing force stronger than the biasing force of the first spring is applied. a second spring provided so that the head of the screw is guided to the tapered part and fitted into the regulation hole; and a holding member for the regulation member, in which the regulation member is slidably provided. The screw is inserted into the screw hole in the previous process and has an inclination due to the difference between the shaft diameter of the screw and the hole diameter of the screw hole, while adjusting the posture of the screw to ensure accurate engagement of the bit and screw. This has the effect of allowing highly efficient screw tightening.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 2 to 5. In the figure, 20 is a guide for the drive shaft 4, which is attached to the plate 15 by a connector 21. A holder 22 is provided on the guide 20 and serves as a holding member for the guide 23. The guide 23 is a screw regulating member, and has a screw regulating hole 23a at one end and a tapered portion 23b for guiding the screw to the regulating hole 23a. Also guide 2
3 is slidable inside the holder 22 and is provided with a rotation prevention pin 24, and the pin 24 is slidable inside the holder 22.
It slides along a long hole 25 provided in the. A compression spring 26 biases the guide 23 with a weak attachment strength. 27 has a spring constant larger than that of the compression spring 26, is provided with a free length along the outer periphery of the compression spring 26, and is provided so as to bias the guide 23 at a position where the guide 23 has slid a certain distance. . 28,
29 is a spring seat. 30 is a C-shaped retaining ring for a stopper of the guide 23 provided on the holder 22. Reference numeral 31 indicates a screw having an extremely long length under the neck compared to the shaft diameter, and 32 indicates a thick member to be fastened.

The operation of the screw tightening machine configured as above will be described below.

In FIG. 2, the screw 31 has been inserted into the screw hole in the previous screw insertion step. At this time, the screw 31 has a certain degree of inclination due to the difference between the hole diameter provided in the fastened member 32 and the shaft diameter of the screw.

In FIG. 3, due to the operation of the air cylinder 9, the screw tightening head consisting of the electric screwdriver 1 to the guide 23 is lowered, and the guide 23 comes into contact with the screw 31. And a screw 31 having an inclination
After standing upright along the tapered portion 23b provided at one end of the guide 23, the guide 23 engages with the regulation hole 23a of the screw. At this time, a force from a compression spring 26 having a small spring constant is acting on the guide 23. However, if the screw 31 has a large inclination and is pressurized only by the compression spring 26 having a small spring constant, the screw 31 may not be correctly regulated in the guide 23. At this time, as shown in FIG. 4, in addition to the pressure applied by the compression spring 26, the screw 31 is engaged with the regulation hole 23a of the guide 23 by a large pressure applied by the compression spring 27 having a large spring constant.

In this way, the head of the screw 31 is fitted into the regulation hole provided in the guide 23 for regulation, and the bit 5 and the screw 31 are accurately engaged. This allows accurate screw tightening as shown in FIG.

Effects of the invention As described above, the present invention corrects the posture of the screw inserted with an inclination when tightening the long screw under the neck inserted into the screw hole in the previous process. The bit and screw are accurately engaged to provide highly reliable screw tightening.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view of a conventional screw tightening machine, and FIGS. 2, 3, 4, and 5 are sectional views of essential parts of a screw tightening machine according to an embodiment of the present invention. . 22...Holder, 23...Guide, 23a...
... Regulation hole, 26, 27 ... Compression spring, 31 ... Screw, 32 ... Fastened member.

Claims (1)

[Scope of utility model registration request] After a long screw under the neck is inserted into a predetermined tightening hole, the head of the screw is brought into contact with a regulating member to stand the screw upright, and the screw is tightened with a bit, the regulating member having one end. a guide part having a regulation hole that can be fitted with the head of the screw and a tapered part formed to guide the screw into the regulation hole; a holder part provided so that the guide part can be slid in the axial direction; a first spring that biases the screw to stand upright by a contact force when the tapered portion of the guide portion abuts the head of the screw; and a biasing force greater than the biasing force of the first spring. A screw characterized in that a second spring having a strong biasing force and biased so that the screw can be tightened while maintaining the screw in an upright state is provided between the guide portion and the holder portion. Tightening machine.