JP7393243B2 - screw tightening machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a screw tightening machine that fastens a screw fed by air pressure from a feeder to a workpiece.

First, the configuration of a conventional screw tightening machine will be described below based on Patent Document 1 and Patent Document 2. A conventional screw tightening machine includes a feeder that forces the screw forward using compressed air, a chuck unit that can temporarily hold the screw discharged from the feeder, and a screw tightening tool that can engage the screw. Equipped with.

The feeder includes a basket that stores a large number of screws, a scoop plate that swings up and down in the basket to suspend and scoop up the screws, and aligns the screws that slide from above to below by the operation of this scoop plate. A vibrating rail is arranged in front of the vibrating rail to transport the screws forward, and the screws are received from the vibrating rail and allowed to fall downward, and are supplied to the chuck unit using compressed air. Further, the feeder and the chuck unit are connected by a hose having an inner diameter that allows the screw to pass through.

The chuck unit includes a chuck body into which the screw tightening tool can be inserted, a chuck claw which is openable and closable at the tip of the chuck body and can hold the screw, and a chuck claw which is swingably disposed in the chuck body and which holds the screw. and a swinging pipe capable of transmitting compressed air, and a stopper disposed at the tip of the swinging pipe.

In the conventional screw tightening machine configured in this way, when the screw tightening tool passes through the chuck body, the swing pipe is swung toward the stopper side, and the screw held by the chuck claw is removed. Screws are tightened to the workpiece by adsorption. In this way, while the screw tightening tool is swinging the swinging pipe, if the feeder supplies the next screw with air pressure, the screw can be kept in the swinging pipe by the stopper. . Eventually, when the screw tightening to the workpiece is completed, the screw tightening tool will return to its original height position, but at this time, the swinging pipe that was in the swinging state will be disengaged from the screw tightening tool, causing the screw tightening tool to return to its original height position. Since it communicates with the chuck jaw and swings back to its original position, the screw that was previously held in the swing pipe moves to the chuck jaw and is held there. Therefore, the conventional screw tightening machine is characterized in that the next screw tightening operation can be performed immediately after the screw tightening tool returns, and the screw tightening time can be shortened.

Japanese Patent Application Publication No. 2018-070328 Japanese Patent Application Publication No. 2018-199188

However, with conventional screw tightening machines, air is fed to the next screw at the same time as the swinging pipe is swinging toward the stopper, so the compressed air that passes through the hose from the feeder is used to swing the swinging pipe toward the stopper. There was a problem with the water ejecting from between the pipes. Therefore, compressed air is scattered around the workpiece, and there is a problem in that small dust and the like tend to adhere to the workpiece.

The present invention includes a feeder that feeds screws under pressure using compressed air, a chuck unit that can temporarily hold the screws discharged from the feeder, and a screw tightening tool that can engage the screws. In the screw tightening machine, the chuck unit includes a chuck body into which the screw tightening tool can be inserted, a chuck claw which is openable and closable at the tip of the chuck body and can hold the screw, and a chuck claw which can freely swing on the chuck body. and an air recovery unit that sucks the compressed air supplied to the chuck unit. The compressed air is configured to be switched from a communicating state to a non-communicating state with the chuck claw, and the air recovery unit is configured to suck the compressed air discharged from the swing pipe in the non-communicating state. shall be. The chuck unit is arranged to prevent the compressed air passing through a gap between a stopper disposed at the tip of the swinging pipe and the stopper from scattering to the outside. It is preferable that the air recovery unit is connected to the air recovery unit. Further, it is preferable that the cover member is disposed at a height farther from the upper surface of the workpiece than the tip of the chuck claw.

In the screw tightening machine according to the present invention, the chuck claw and the feeder are out of communication with each other due to the swinging of the swinging pipe. Since the compressed air discharged from the supply machine during this non-communicating state can be sucked and recovered by the air recovery unit, there is an advantage that small dust etc. released with the compressed air can also be recovered by the air recovery unit. Therefore, it is difficult to contaminate the workpiece during screw tightening work, and it can be used for screw tightening of so-called contamination-resistant workpieces such as semiconductors and electronic devices. Further, in the screw tightening machine according to the present invention, since a stopper is arranged at the tip of the swinging pipe that is in the non-communicating state, the next screw is tightened while the swinging pipe is swinging. can be supplied to the chuck unit. This allows the screw to be force-fed while it is being tightened, which has the advantage of shortening the screw tightening time and making it difficult for compressed air to spread around the workpiece. Further, in the screw tightening machine according to the present invention, the cover member is set at a height higher than the position of the chuck claw so that the cover member is not disposed at a position closest to the work surface. This also has the advantage that the connection member that connects the cover member and the air recovery unit is unlikely to interfere with the workpiece during screw tightening work. Furthermore, the screw tightening machine of the present invention equipped with this cover member and stopper can retain compressed air leaking from the swing pipe on the inner surface of the cover member and stopper, thereby increasing the air recovery ability of the air recovery unit. Another advantage is that it is easy to prevent compressed air from scattering to the outside.

FIG. 1 is a schematic explanatory diagram of a screw tightening machine according to the present invention. FIG. 2 is a schematic explanatory diagram for explaining an operation in which the swing pipe swings from the state shown in FIG. 1 and discharges the screw S to the chuck jaw.

As shown in FIGS. 1 and 2, the screw tightening machine 1 according to the present invention includes a feeder F that forces the screw S forward using compressed air, and a screwdriver F that temporarily holds the screw discharged from the feeder F. The chuck unit 10 includes a chuck unit 10, a screw tightening tool 20 that can engage the screw S, and an air recovery unit V that sucks the compressed air supplied to the chuck unit 10.

The feeder F is configured to be able to scoop up a large number of screws S stored in advance, carry them forward in alignment, and feed the screws S one by one into a hose H connected to the chuck unit 10. Further, this feeder F is configured to inject compressed air into the hose H, and is configured to be able to transport the screw S that has remained within the hose H into the chuck unit 10 using the compressed air.

The hose H has an inner diameter slightly larger than the head of the screw S. Further, the screw S is preset to have a shaft length corresponding to the diameter of the head so that the screw S does not rotate in such a way that the head and shaft are reversed while passing through the hose H.

The screw tightening tool 20 includes a bit B connected to a rotationally driven bit rotation motor M, and a screw guide 21 that normally contains the bit B. The bit B is formed into a tip shape that can be engaged with the screw S. Further, the screw tightening tool 20 is connected to a reciprocating means (not shown) that reciprocates in the direction approaching the workpiece W, and sucks air from the tip of the screw guide 21 into the screw guide 21. It is connected to a screw suction means Z that can hold the screw S by suction.

The screw guide 21 is normally biased in the axial direction by a cushion spring (not shown), and is configured to be movable relative to the bit B. Further, as shown in FIG. 2, the bit B is always located a predetermined distance back from the tip of the screw guide 21, and is set in advance so that the screw S sucked into the screw guide 21 does not protrude from the screw guide 21. Dimensions are set.

The chuck unit 10 includes a chuck body 11 into which the screw guide 21 can be inserted, a chuck claw 12 which is disposed at the tip of the chuck body 11 so as to be openable and closable and can suspend and temporarily hold the screw S, and a chuck. A swinging pipe 13 that is swingably disposed on the main body 11 and is capable of passing compressed air through the screw S, and a swinging pipe 13 that prevents the compressed air supplied from the feeder F to the chuck unit 10 from leaking to the outside of the chuck unit 10. and an air recovery unit V that sucks and recovers the air. Further, the chuck unit 10 allows the compressed air that has passed through a gap between a stopper 18 disposed at the tip of the swinging pipe 13 and the stopper 18 and the swinging pipe 13 in a swinging state to the outside. The cover member 19 is arranged to prevent scattering.

The chuck main body 11 is provided with an insertion hole 11a through which the screw guide 21 can be inserted while guiding it. The chuck main body 11 also includes a swinging pipe 13 arranged at one end thereof and arranged so as to normally close the insertion hole 11a, and a pair of chuck claws 12 (12) capable of receiving a screw S from the swinging pipe 13. ) are attached so that they can swing or open and close. Furthermore, this chuck body 11 is attached to an articulated robot (not shown) or the like that can move above the workpiece W, and is fixed to a base member 6 arranged to protrude from the articulated robot. .

The chuck claw 12 has a large-diameter groove 12a through which the screw S can pass and the tip of the screw tightening tool 20, and a groove depth that gradually decreases from this large-diameter groove 12a to pass through the shaft of the screw S. A small diameter groove 12b whose diameter can be reduced, and is normally urged in a direction to close each other by a chuck pawl spring (not shown). The pair of chuck claws 12 (12) in this closed state can hold the head of the screw S so as to hang it while guiding the shaft portion of the screw S through the opposing small diameter grooves 12b (12b).

The swing pipe 13 is arranged so as to be inclined with respect to the insertion hole 11a, and is swingably supported by a hose joint 14 attached to the chuck body 11. Moreover, this swing pipe 13 is provided with a passage hole 13a that is slightly larger than the head diameter of the screw S to be passed through, and is closer to the chuck claw 12 than the swing center X of the swing pipe 13 shown in FIG. It is constantly biased by a swinging pipe spring 17 located at.

As a result, the swing pipe 13 is normally in communication with the closed chuck claw 12 (12) as shown in FIG. Note that the state shown in FIG. 1 is different from the state shown in FIG. 2, and since the swing pipe 13 is not swinging, it is in a state of no communication with the closed chuck claw 12 (12).

Further, the swing pipe spring 17 is arranged in a holder 16 fixed to the chuck body 11, and the holder 16 is provided with a notch so as not to interfere with the outer peripheral surface of the swing pipe 13. There is. The hose joint 14 also has an insertion port 14a into which the hose H can be inserted, and a guide path 14b that guides the screw S discharged from the hose H to the swing pipe 13 by narrowing the diameter from the insertion port 14a. Be prepared. A male thread is formed on the outer periphery of the hose joint 14, and this male thread is configured to be screwed into a cap 15 that prevents the hose H inserted into the hose joint 14 from coming off.

The stopper 18 is configured to close the passage hole 13a to prevent the screw S in the swing pipe 13 from being ejected when the swing pipe 13 in the non-communicating state is in the swing state as shown in FIG. The chuck jaws 12 (12) are fixedly disposed above the chuck jaws 12 (12).

The cover member 19 includes a plate member 19a bent into a U-shape and a pipe connection portion 19b welded to the plate member 19a, and is arranged to connect the stopper 18 and the holder 16. In this way, the cover member 19 is arranged so as to surround the stopper 18 and the holder 16, so that the compressed air discharged from the passage hole 13a of the swing pipe 13 which is in a non-communicating state is directed inside the plate member 19a. It is easy to keep it in the space G where it is located. Further, the cover member 19 is arranged axially further away from the upper surface Wb of the workpiece W than the tip of the chuck jaw 12 (12) in the closed state, and extends into the space below the chuck jaw 12. It is set up so that nothing happens. This makes it difficult for the chuck unit 10 to interfere with the workpiece W located below the chuck jaws 12.

The air recovery unit V is configured to suck air when activated. Further, this air recovery unit V is configured by connecting one end of an air pipe (not shown) and connecting the other end of the air pipe to the cover member 19. Thereby, the air recovery unit V can suck the compressed air flowing out from one end of the swing pipe 13 into the space G located inside the plate material 19a, so that small dust particles present in the passage path of the compressed air can be sucked. etc. can also be taken into the air recovery unit V. Therefore, it is difficult for so-called contamination to adhere to the workpiece W.

The operation of the screw tightening machine 1 according to the present invention configured as described above will be explained based on FIGS. 1 and 2. First, as shown in FIG. 2, the screw tightening tool 20 remains in a standby position where it does not come into contact with the swing pipe 13, and the screw S is held by the chuck claw 12 (12) in a closed state. In this state, screw tightening work can be performed, so the articulated robot moves the chuck unit 10 above the female thread Wa, which is the tightening point of the workpiece W, and maintains the state shown in FIG. 2. .

In response to this, the screw suction means Z, the bit rotation motor M, and the reciprocating means are operated, so that the bit B is rotated at a predetermined rotational speed, and the bit B and the screw guide 21 are moved toward the workpiece W. Descend to approach the target. Thereby, the screw guide 21 passes through the insertion hole 11a of the chuck body 11 and comes into contact with the swing pipe 13. Even after this contact, the screw guide 21 is lowered together with the bit B by the reciprocating means, so that the swing pipe 13 gradually begins to swing from the swing center X as a starting point.

As shown in FIG. 1, when the swing pipe 13 comes into contact with the outer periphery of the descending screw guide 21 and swings to the stopper 18 position, the passage hole 13a is opened by the stopper 18 with a slight gap. It becomes out of communication with the chuck claw 12.

In this way, when the swing pipe 13 swings to the stopper 18 position, the supply machine F and the air recovery unit V are activated. Therefore, the next screw S passes through the hose H and the hose joint 14 in this order, and is supplied to the swinging pipe 13 that is swinging. At this time, since the passage hole 13a of the swing pipe 13 is closed by the stopper 18, the next screw S comes into contact with the stopper 18 and remains in the passage hole 13a.

The feeder F also air-feeds the next screw S to the swing pipe 18. As a result, the compressed air is supplied in the direction of arrow A shown in FIG. The compressed air that has entered this space G is sucked by the air recovery unit V that is operating at this time, so that the release of compressed air to the outside due to air pressure feeding by the screw S is reduced.

Note that the supply device F has a timer set in advance for the discharge time of compressed air, and this timer setting value is appropriately determined depending on the length of the hose H, for example, and is a condition for ensuring that the screw S reaches the stopper 18. It is set as follows. Further, the air recovery unit V, which operates simultaneously with the supply machine F, is set to operate for a slightly longer time than the timer setting of the supply machine F, so as to reliably recover compressed air.

By the way, when the aforementioned swinging pipe 13 starts swinging due to the descending screw guide 21, the screw guide 21 enters into the large diameter groove 12a of the chuck claw 12 in the closed state. At this time, since the screw guide 21 is suctioning air from its tip by the operation of the screw suction means Z, the screw S held in the chuck claw 12 in the closed state is suctioned and held in the screw guide 21. Ru.

The screw guide 21, which continues to descend, approaches the workpiece W while holding the bit B and the screw S therein, pushes out the closed chuck claws 12 (12), and comes into contact with the upper surface Wb of the workpiece W.

In this way, when the screw guide 21 comes into contact with the upper surface Wb of the workpiece W, the cushion spring is bent, and the bit B begins to move relatively toward the tip side of the screw guide 21. Further, at this time, since the bit B is imparting rotation to the screw S engaged with the bit B, the screw S is screwed into the female thread Wb and fastened with a predetermined torque.

When the screw S is completely fastened, the bit rotating motor M and the screw suction means Z stop, while the reciprocating means raises the screw guide 21 and the bit B to the standby position shown in FIG. 2. As the screw guide 21 rises, the swing pipe 13 is pushed back by the bent swing pipe spring 17 and returns to the state shown in FIG. 2 with the swing center X as the starting point. As a result, the swing pipe 13 is brought into communication with the chuck claw 12 in the closed state, so the next screw S that was fastened in the passage hole 13a is received by the chuck claw 12 (12) in the closed state. passed on.

The screw tightening machine 1 according to the present invention not only discharges the compressed air to the outside as described above, but also has an air recovery unit V that sucks in the compressed air, so that dust attached to the screw S that is fed by air pressure, etc. The attached matter is also easily collected by the air collection unit V. Therefore, there is an advantage that a clean screw S can be fastened to the workpiece W.

1... Screw tightening machine 10... Chuck unit 11... Chuck body 12... Chuck jaw 13... Swinging pipe 19... Cover member 20... Screw tightening tool 21... Screw guide B... Bit rotation motor F... Supply machine S... Screw V... Air Collection unit W … Work

Claims (3)

A screw tightening machine comprising: a feeder for feeding screws by compressed air; a chuck unit capable of temporarily holding the screws discharged from the feeder; and a screw tightening tool capable of engaging the screws. ,
The chuck unit includes a chuck body into which the screw tightening tool can be inserted, a chuck claw which is openable and closable at the tip of the chuck body and can hold the screw, and a chuck claw which is swingably disposed in the chuck body and which holds the screw. and an air recovery unit that sucks the compressed air supplied to the chuck unit,
The swing pipe is configured to switch the swing pipe and the chuck claw from a communicating state to a non-communicating state by swinging,
The screw tightening machine characterized in that the air recovery unit is configured to suck the compressed air discharged from the non-communicating swing pipe. The chuck unit includes a stopper disposed at the tip of the swinging pipe, and is arranged so as to prevent the compressed air passing through a gap between the swinging pipe in the swinging state and the stopper from scattering to the outside. and a cover member;
The screw tightening machine according to claim 1, wherein the cover member is connected to the air recovery unit. 3. The screw tightening machine according to claim 2, wherein the cover member is disposed at a height farther from the upper surface of the workpiece than the tip of the chuck claw.

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