JPH0561057B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to vertically moving a pipe that is provided opposite to a chute that holds screws and that forms a screw supply port that is supplied by air pressure through a hose. The present invention also relates to a screw feeding method for an automatic screw tightening machine, which prevents the screws from swinging or reversing on the chute when air is pumped, and enables reliable screw feeding and screw tightening.

Construction of a conventional example and its problems The screw feeding method of a conventional screw tightening machine will be described based on Japanese Patent Publication No. 58-43231. Tokko Akira
The screw tightening machine disclosed in Publication No. 58-43231 includes a chute that holds the screws that are fed with air under pressure, a pusher that pushes and moves the screws placed on the chute, and a screw that is located below the bit and is pushed out from the chute. a catcher to receive the screw, and a lever for preventing swinging, the tip of which is located within the chute, is provided to hold the screw between the tip of the pusher, and is biased by the screw in the direction of holding the screw. The screw feeding device is equipped with a screw feeding device. If the under-neck of the screw that is being pumped with air is longer than the head diameter, the anti-swing lever prevents the screw from swinging due to the impact of air pumping or causing the screw to overturn due to the swing, and the screw can be properly chuteed. Retained. However, if the bottom of the screw neck is shorter than the head diameter, when the screw is fed onto the chute by air pressure from the pipe that is the screw supply port provided opposite to the chute, the impact of the air pressure may cause the pipe to There was a problem in that the screw reversed in the area surrounded by the end face, chute, pusher and lever.

Purpose of the Invention The present invention solves the above-mentioned drawbacks, and even if the under-neck of the screw is shorter than the head diameter, the screw does not swing or reverse due to the impact when air is pumped on the chute. The present invention provides a screw supply method for an automatic screw tightening machine that is capable of supplying screws and tightening screws.

Structure of the Invention The present invention provides a screw supply port having a hole through which a screw can pass, receives and holds the screw, and then descends toward a chute through which the screw can be transferred, and an end face of the screw supply port is directed against the chute. A process in which the screw is stopped with a slight gap or in contact with the chute, and after this process, a process in which the screw is fed onto the chute from the screw supply port by air pressure, and a screw feed process in which the screw is fed and held onto the chute. a step in which the end surface of the mouth moves away from the chute and rises to its original position and stops;
A step in which the screw held on the chute is transferred to a catcher connected to the end of the chute directly under a suction pipe provided at a certain distance from the screw supply port while being pushed by a pusher, and then held by the pusher. When the screw returns to its original position and stops, the suction pipe descends, and the screw is tightened while holding the screw held by the catcher and the suction pipe by vacuum suction. Screws can be reliably fed in the correct posture by preventing movement or reversal.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 7.
The explanation will be based on the diagram. Reference numeral 1 denotes a rotational drive source, to which a bit 5 is connected via universal joints 2a, 2b, an intermediate shaft 3, and a drive shaft 4. 6 is a pipe with a suction pipe 7 fixed to its tip,
The other end is connected to a vacuum suction device (not shown) via an air hose 8. Reference numeral 9 denotes a guide block for the pipe 6, on which the pipe 6 is slidably provided. Reference numeral 10 denotes a spring for absorbing the level difference in the workpiece during screw tightening. Reference numeral 11 denotes an air cylinder, which is connected to a plate 14 attached to a bracket 13 that is slidable along a slide shaft 12. The operation of the air cylinder 11 is performed by the plate 14.
and is transmitted to plate 16 via rod 15. Plate 16 is mounted on a bracket 17 that is slidable along slide axis 12. 1
8 and 19 are stoppers. 20 is a plate, and 21 is a guide fixed to the plate 20 on which the suction pipe 7 and the pipe 6 can slide.

A pipe 22 is provided at a certain distance from the suction pipe 7, and a screw 24 is supplied with air under pressure from a screw supply device (not shown) through a hose 23.
This is the screw supply port. A block 25 holds the pipe 22 and is fixed to the shaft 26. 2
7 is a spring that biases the block 25. 28 is a block on which a shaft 26 is slidably provided. A pin 29 is fixed to the shaft 26 and is slidable in an elongated hole 30 of the block 28. 3
A cam follower 1 is fixed to one end of the shaft 26. 32 is a plate cam, cam follower 31
The pipe 22, which is fixed to the block 25 through the shaft 26, is caused to move up and down.

33 is a chute with V-shaped inclined surfaces 34a, 3
4b and a groove 35 slightly larger than the diameter of the lower neck of the screw, and the head of the screw 24 fed with air is held by the inclined surfaces 34a, 34b, and the lower part of the neck is held by the groove 35. The end surface of the pipe 22 also has a V-shaped slope that matches the slopes 34a and 34b of the chute 33. A pusher 36 is movable while contacting the head and lower neck of the screw 24 held in the chute 33, and performs reciprocating motion along the groove 35 of the chute 33. Reference numeral 37 is a drive source for the reciprocating motion of the pusher 36, to which the plate cam 32 is fixed, and also serves as a drive source for the vertical motion of the pipe 22 via the cam follower 31, shaft 26, and block 25.
A catcher 38 is provided directly below the suction pipe 7 and connected to the end of the chute 33, and holds the screw 24 pushed out from the chute 33 by the pusher 36.
Rotational movement around 0 is possible.

41 is a spring biasing the catcher 38;
Reference numeral 2 designates a stopper of the catcher 38 which is biased by a spring 41. 43a and 43b are stoppers for the drive source 37. 44a and 44b are plate 4
The chute 33, driving source 37, and stoppers 43a, 43b are fixed by a plate fixed to the plate 5. 46 is a member to be fastened, and 47 is a screw hole member.

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

When the drive source 37 moves from the state in which the pusher 36 is located on the catcher 38 side to the pipe 22 side as shown in FIG.
The pipe 22, which had been pushed up by the cam follower 31, is pushed down together with the cam follower 31, and the pipe 22
The end surface of the chute 33 contacts the inclined surfaces 34a and 34b (first step), and the drive source 37 contacts the stopper 4.
3a and stops, resulting in the state shown in FIG. In this state, the screw 24 is supplied by a screw supply device (not shown) through the hose 23 and the pipe 22 by air pressure and held in the chute 33 (second step). At this time, the screw 24 has its head facing the inclined surfaces 34a, 3.
4b, the lower part of the neck is held by the groove 35, but as shown in FIG. The space formed by the chute 33 and the pipe 22 is minimized so that the head of the screw is always held inside the pipe 22. Also, due to the impact of air pressure, the screw 24
Even if it swings along the groove 35, the lower part of its neck hits the end face of the pipe 22 blocking the groove 35, as shown in FIG. 6, so it can be held in the correct posture without being turned over. .

Next, the drive source 37 operates again, the plate cam 32 separates from the cam follower 31, and the pipe 22 is pushed upward together with the block 25 by the spring 27, returns to its original position, and stops (third step). and,
After the screw 24 held by the chute 33 is pushed and transferred by the pusher 36, it is pushed out and held by the catcher 38 as shown in FIG. 7 (fourth step). When the screw 24 is held in the catcher, the drive source 37 is operated to return the pusher 36 to the state shown in FIG. Next, air cylinder 1
1 is operated, and the screw tightening head portion consisting of the rotary drive source 1 to the suction pipe 7 fixed to the plates 14 and 16 is lowered. At this time, the vacuum generator (not shown) and the rotary drive source 1 also operate, and as the suction pipe 7 descends, the screw 24 held by the catcher 38 is moved to the suction pipe 7.
While holding the fastened member 4 by vacuum suction and pushing down the catcher 38,
6 and the screw hole member 47 are tightened (fifth step).

In addition, in the present invention, since the driving source for the vertical movement of the pipe 22 and the driving source for the reciprocating movement of the pusher 36 are the same driving source 37, the operations of the above-mentioned first to fifth steps are performed simultaneously over two steps. Although there are parts, the structure is such that it does not affect the operation between each process. Further, it is also possible to separately provide a driving source for the vertical movement of the pipe 22 and a driving source for the reciprocating movement of the pusher.

Effects of the Invention As described above, the present invention has an advantage in that the pipe which has the same end face shape as the inclined face of the chute having a V-shaped inclined face and which is the supply port for the screw to which the air is pumped is moved up and down. It is possible to prevent the screw from swinging or reversing due to the impact during pressure feeding, and to reliably feed the screw in the correct posture, thereby making it possible to tighten the screw with high reliability.

[Brief explanation of the drawing]

Fig. 1 is a side view of an automatic screw tightening machine according to an embodiment of the present invention, Fig. 2 is a sectional view taken along line AA in Fig. 1, Fig. 3 is a sectional view taken along line BB in Fig. 2, and Fig. 4. is a sectional view taken along the line CC in Fig. 2, Figs. 5 and 6 are sectional views of main parts when the screw is being fed by air, and Fig. 7 is a sectional view of the screw in Fig. 1 showing the state in which the screw is transferred to the catcher by a pusher. It is a sectional view taken along the AA line. 6... Bit, 7... Adsorption pipe, 22... Pipe, 26... Shaft, 27... Spring, 31...
...Cam follower, 32...Plate cam, 33...Chute, 34a, 34b...Slanted surface, 35...Groove,
36... Pusher, 37... Drive source, 38...
Catcher.

Claims (1)

[Claims] 1. A chute configured to hold the head of the screw with a V-shaped inclined surface and the lower part of the neck of the screw with a groove, and the screw held by the chute with the head and lower part of the neck abutting each other. A pusher with a transfer function, and a hole through which a screw can pass, and the tip thereof descends to a position where it contacts or has a slight gap with the inclined surface of the chute, and then stops and moves to a position where it does not contact the pusher. and a screw supply port configured to be able to move up and down so as to rise, and the screw supply port descends and stops at a position where its tip end surface comes into contact with or has a slight distance from the inclined surface of the chute. a step of supplying the screw from the screw supply port onto the chute by air pressure after the step; and when the screw is supplied and held on the chute, the screw supply port moves away from the chute and rises to its original position. and stopping the screw held on the chute by the pusher, while pushing the screw held on the chute to a catcher connected to the end of the chute directly below the suction pipe provided at a certain distance from the screw supply port. A step of holding the screw after being transferred, and a step of tightening the screw while the pusher returns to its original position and stops, the suction pipe descends, and the screw held by the catcher is held by vacuum suction to the suction pipe. A screw feeding method for an automatic screw tightening machine consisting of: