JP7108252B2 - Supply rod for cap nuts and supply method - Google Patents

Description

The present invention relates to supplying a cap nut having a hemispherical cover member coupled to a nut body having a screw hole to a guide pin of a fixed electrode for electric resistance welding.

Japanese Unexamined Patent Application Publication No. 2006-136937 describes advancing a supply rod in an inclined posture holding a projection nut, and supplying a guide pin of a fixed electrode while causing the nut to draw an arc locus.

JP 2006-136937 A

The technique described in the above-mentioned patent document supplies a single nut, and is not suitable for supplying a cap nut in which a hemispherical cover member is coupled to the nut body. If the nut is a single unit, the position of the center of gravity is low, so the nut is supplied to the guide pin of the fixed electrode while reliably drawing an arc locus. However, in the case of the cap nut-like shape, the position of the center of gravity is high, so it is difficult to reliably draw the arc locus.

The present invention has been provided to solve the above problems, by adapting the shape of the cap nut to allow the cap nut held on the supply rod to move in an arc and move to the tip of the supply rod. To surely supply a guide pin of a fixed electrode by using rubbing movement together.

The invention according to claim 1 is a cap nut supply rod,
A cap nut with a threaded hole opened on one side of the nut body and a hemispherical cover member coupled to the other side, with the center of gravity positioned in the cover member, is used as a guide pin for a fixed electrode for electric resistance welding. that supplies
A holding recess for accommodating the cap nut is formed at the tip of the forward/backward actuating supply rod arranged in an inclined posture,
The holding recess is formed with a main holding surface formed of a wall member surrounding the nut body and a sub-holding surface surrounding the hemispherical portion of the cover member,
A passage notch through which the cap nut passes when shifting from the supply rod to the guide pin is formed in an open state on a lateral side surface opposite to the direction of inclination of the supply rod, and the hemispherical shape of the cover member. has an arc-shaped cover member passage portion through which the portion passes and a nut body passage portion through which the nut body passes,
a permanent magnet is provided on the supply rod so as to be able to move back and forth so that the outer portion of the nut body is in contact with the main holding surface and the hemispherical portion of the cover member is kept in contact with the sub-holding surface;
When the feed rod advances, the threaded hole stops just before the guide pin or at a point where the tip of the guide pin is slightly inserted into the threaded hole. The attraction force of the magnet is extinguished, and as a result of this extinguishing, the cap nut in an inclined posture moves in the vertical direction while drawing an arc locus. to reduce the distance between the center of gravity of the cap nut housed in the holding recess and the tip corner of the wall member, viewed in the direction of the center axis of the supply rod, so that the tip corner is Configured so that the circular arc displacement of the centered cap nut is performed smoothly ,
Reduction of the distance between the center of gravity position and the tip corner of the wall member causes the outer portion of the nut body to come into contact with the main retaining surface and the hemispherical portion of the cover member to contact the sub retaining surface due to the attractive force of the permanent magnet. From the center of gravity position set by the contact state, the cap nut moves in an arc in the vertical direction caused by the disappearance of the attractive force of the permanent magnet, and the outer surface of the nut body descends while rubbing the tip corner of the wall member. It is characterized by being displaced to the set center of gravity position by doing.

The advance of the supply rod stops immediately before the threaded hole of the guide pin or at the point where the tip of the guide pin is slightly inserted into the threaded hole, and almost simultaneously with the stop, the permanent magnet is applied to the cap nut. Due to this disappearance, the cap nut in an inclined posture moves in the vertical direction while drawing an arc trajectory, and at the same time, the outer surface of the nut body moves while rubbing against the tip corner of the wall member. do.

In this way, the movement of the cap nut along an arcuate locus and the rubbing of the outer surface of the nut body against the tip corner of the wall member are performed at the same time. Since the point of contact between the side surface and the tip corner of the wall member is relatively close to the center of gravity of the cap nut, the cap nut is smoothly displaced in an arc centering on the point of contact, and the screw hole is fitted to the guide pin. A match is definitely achieved.

When the plate thickness of the cover member is reduced to reduce its mass and the center of gravity position approaches the nut main body side, the progress of the rubbing movement causes the center of gravity position to move toward the wall member when viewed in the direction of the central axis of the supply rod. is located forward of the tip corner of the In such a case, the arcuate displacement of the cap nut is more likely to be accelerated, and the supply to the guide pin is ensured.

If the outer surface of the nut body does not move while rubbing against the tip corner of the wall member, the distance between the tip corner of the wall member and the center of gravity of the cap nut will increase, and as a result, the cap nut can be moved vertically. The force component moved by the circular arc motion becomes small, and the cap nut is less likely to fall from the holding recess. However, while the cap nut is displaced toward the posture in the vertical direction, the above-mentioned rubbing displacement is compounded, thereby promoting the change in the posture of the cap nut in the arc direction. That is, since the distance between the tip corner of the wall member and the center of gravity of the cap nut is reduced, the orientation of the cap nut is easily changed in the arc direction.

Since the center of gravity of the cap nut is located on the cover member, the holding stability of the cap nut in the holding recess is lowered. A secondary holding surface surrounding the hemispherical portion of the cover member is formed, and the holding of the outer surface of the nut body by the main holding surface and the holding of the cover member by the secondary holding surface are ensured by the attractive force of the permanent magnet. It is Therefore, even if the center of gravity of the cap nut is located on the cover member, the cap nut will not shift in the holding recess when the supply rod advances, so that the holding in the holding recess can be achieved reliably and the supply can be performed. Stable operation of the rod can be achieved. In particular, since the nut body and the cover member are held at two points, the main holding surface and the sub-holding surface, the holding stability of the cap nut is improved. Furthermore, when the angle of inclination of the supply rod approaches the vertical direction, the cap nut tends to escape from the holding recess. is done.

A passage notch through which the cap nut passes when shifting from the supply rod to the guide pin is formed in an open state on the side surface of the supply rod opposite to the direction of inclination, and the hemispherical portion of the cover member It has an arc-shaped cover member passage portion through which the nut body passes and a nut body passage portion through which the nut body passes. Therefore, when the cap nut moves toward the guide pin along with the arcuate movement, the cover member reliably passes through the cover member passing portion, ensuring operational stability. In particular, since the outer surface of the nut body is displaced relative to the tip corner of the wall member, the cover member does not interfere with the cover member passing portion, and a reliable supply operation can be obtained.

The invention according to claim 2 is a cap nut supply method,
A cap nut with a threaded hole opened on one side of the nut body and a hemispherical cover member coupled to the other side, with the center of gravity positioned in the cover member, is used as a guide pin for a fixed electrode for electric resistance welding. that supplies
A holding recess for accommodating the cap nut is formed at the tip of the forward/backward actuating supply rod arranged in an inclined posture,
The holding recess is formed with a main holding surface formed of a wall member surrounding the nut body and a sub-holding surface surrounding the hemispherical portion of the cover member,
A passage notch through which the cap nut passes when shifting from the supply rod to the guide pin is formed in an open state on a lateral side surface opposite to the direction of inclination of the supply rod, and the hemispherical shape of the cover member. has an arc-shaped cover member passage portion through which the portion passes and a nut body passage portion through which the nut body passes,
preparing a supply rod provided with a permanent magnet capable of moving back and forth so that the outer portion of the nut body is in contact with the main holding surface and the semispherical portion of the cover member is kept in contact with the sub-holding surface;
When the feed rod advances, the threaded hole stops just before the guide pin or at a point where the tip of the guide pin is slightly inserted into the threaded hole. The attraction force of the magnet is extinguished, and as a result of this extinguishing, the cap nut in an inclined posture moves in the vertical direction while drawing an arc locus. to reduce the distance between the center of gravity of the cap nut housed in the holding recess and the tip corner of the wall member, viewed in the direction of the center axis of the supply rod, so that the tip corner is Circular displacement of the centered cap nut is performed smoothly,
Reduction of the distance between the center of gravity position and the tip corner of the wall member causes the outer portion of the nut body to come into contact with the main retaining surface and the hemispherical portion of the cover member to contact the sub retaining surface due to the attractive force of the permanent magnet. From the center of gravity position set by the contact state, the cap nut moves in an arc in the vertical direction caused by the disappearance of the attractive force of the permanent magnet, and the outer surface of the nut body descends while rubbing the tip corner of the wall member. It is characterized by being displaced to the set center of gravity position by doing.

The effect of the supply method invention is the same as the effect of the supply rod invention described above.

It is the whole supply apparatus, and sectional drawing of each part. It is a sectional view of each part of a supply rod. It is sectional drawing which shows the operation|movement order.

Next, a form for carrying out the cap nut supply rod and supply method of the present invention will be described.

1-3 show an embodiment of the invention.

First, the cap nut will be explained.

As shown in FIGS. 1(C) and 1(D), a cap nut 1 made of iron has a screw hole 3 on one side of a nut body 2 and a hemispherical cover member 4 integrated on the other side. The cover member 4 is formed by pressing a steel plate and welded to the end surface of the nut body 2 . The blackened portion is the welded portion 5 .

A fixed electrode 6 for electric resistance welding is provided with a guide pin 7 protruding from a prepared hole 9 of a steel plate component 8 placed thereon. When the cap nut 1 is supplied to the guide pin 7 by a supply device 100, which will be described later, the small diameter portion 10 of the guide pin 7 relatively enters the screw hole 3, and the opening edge of the screw hole 3 tapers the guide pin 7. 11 tapered surfaces are received. A movable electrode which is arranged coaxially with the fixed electrode 6 and moves back and forth is omitted from the drawing.

As shown in FIG. 1(C), the center of gravity of the nut body 2 alone is G1 on the nut central axis, which is located at a low position. On the other hand, when the cap nut 1 is integrated with the cover member 4, the position of the center of gravity is displaced to the cover member 4. As shown in FIG. This center of gravity position is indicated by G2. That is, the center of gravity G2 is a high point. The position of the center of gravity G2 can be displaced toward the nut body 2 by reducing the thickness of the steel plate of the cover member 4 to reduce the mass.

Next, the supply device will be explained.

The supply device 100 performs a function of feeding the cap nut 1 to the guide pin 7 by advancing and retreating the supply rod 14 holding the cap nut 1 at its tip. The supply device 100 as a whole is inclined so that the supply rod 14 is inclined with respect to the vertical direction.

The supply rod 14 is accommodated in an outer cylinder 17 having a circular cross section, and its upper end is connected to a piston rod 19 of an air cylinder 18 fixed to the outer cylinder 17 . When the supply rod 14 advances by a predetermined length, the suction force to the cap nut 1 is substantially extinguished. A mechanism is used for this purpose. An outer cylinder 17 is fixed to a stationary member 15 such as a machine frame.

Various methods such as a structure using a vacuum or an electromagnet can be adopted as the attraction force for the cap nut 1 . Here, a method is employed in which the permanent magnet is advanced and retracted by a shaft member.

That is, the supply rod 14 is composed of a hollow shaft 20 and an inner shaft 21 slidably inserted therein. A regulating pin 22 fixed near the upper end of the inner shaft 21 protrudes into the space inside the outer cylinder 17 through an elongated hole 23 formed in the hollow shaft 20 in the stroke direction. An air cylinder 24 is fixed to the outer peripheral surface of the outer cylinder 17, and an engaging piece 26 is connected to a piston rod 25 thereof. It protrudes into the outer cylinder 17 .

The tension of the compression coil spring 28 inserted into the hollow shaft 20 acts on the inner shaft 21 , thereby pressing the regulating pin 22 against the lower end of the long hole 23 . In this state, the hollow shaft 20 and the inner shaft 21 have distal end portions formed with holding recesses, which will be described later.

The relative positions of the two are set so that the restricting pin 22 stops immediately before the engaging piece 26 when the supply rod 14 advances over a predetermined length due to the operation of the air cylinder 18 .

A permanent magnet 16 is embedded in the tip of the inner shaft 21 . By retracting the inner shaft 21, the suction force to the cap nut 1 is extinguished.

The inner shaft 21, the hollow shaft 20, etc. are preferably made of stainless steel, which is a non-magnetic material, in order to make the permanent magnet 16 attract the cap nut 1 more strongly. As shown in FIG. 1B, the supply rod 14 has an oval cross-sectional shape with two parallel planes 30 formed thereon. A piece 31 is fixed to the inner surface of the outer cylinder 17 by bolting or the like.

A parts supply pipe 33 for guiding the cap nut 1 from a parts feeder (not shown) extends in a direction perpendicular to the stroke direction of the supply rod 14 .

A permanent magnet 33 is arranged at the end of the outer cylinder 17 to draw the cap nut 1 from the component supply tube 33 to the supply rod 14 . A permanent magnet 34 is housed in a container 35 which is welded to the end of the outer cylinder 17 .

Next, the holding concave portion will be explained.

The holding recess 36 for accommodating the cap nut 1 has a main holding surface 38 formed by a wall member 37 surrounding the nut body 2 and a secondary holding surface 38 surrounding the hemispherical portion of the cover member 4 . A holding surface 39 is formed. The outer portion of the nut body 2 is composed of six outer side surfaces and six corner portions of the nut body 2 which are hexagonal. When the nut body 2 is surrounded by the main retaining surface 38, as shown in FIG. A slight gap exists between the retaining surfaces 38 .

The inner surface of the sub-retaining surface 39 is formed as a spherical concave surface 40 so that the hemispherical portion of the cover member 4 is tightly fitted. Correspondingly, as shown in FIG. 3D, the end surface of the inner shaft 21 is also formed as a concave surface 41 .

In addition, in FIG. 3, the hatching of the cross section is not shown for the sake of clarity.

Next, the passage notch will be explained.

A passage notch 42 shown in FIG. As shown in FIGS. 2(A) and 3(D), the passage notch 42 is formed in an open state on the side surface (flat surface 30) opposite to the direction of inclination of the supply rod 14. When the rod 14 is most retracted, it faces the exit portion of the component supply pipe 33 .

The passage notch 42 has an arc-shaped cover member passage portion 43 through which the hemispherical portion of the cover member 4 passes, and a nut body passage portion 44 through which the nut body 2 passes.

Next, the tip corner portion of the wall member will be described.

An inner edge portion of the wall member 37 is a tip corner portion indicated by symbol S. As shown in FIG. As shown in FIGS. 3(A) and 3(D), the distance between the tip corner S and the center of gravity G2 when the cap nut 1 is accommodated in the holding recess 36 when viewed in the central axis direction of the supply rod 14 is labeled L1.

Next, the cap nut supply operation will be described.

In FIG. 3A, the attractive force of the permanent magnet 16 acts on the cap nut 1, the entire cap nut 1 is accommodated in the holding recess 36, and the supply rod 14 advances only when the screw hole 3 is positioned just before the guide pin 7. In FIG. is stopped at the point reached. Note that this stop position may be a position where the guide pin 7 is slightly inserted into the screw hole 3 . Here, as shown in FIG. 3B, when the inner shaft 21 is retracted by the contraction operation of the air cylinder 24, the permanent magnet 16 moves away from the cover member 4, and the attraction force of the cap nut 1 substantially disappears. .

As a result of this disappearance, the cap nut 1 moves in an arc in the vertical direction and the outer surface of the nut body 2 moves downward while rubbing against the tip corner portion S of the wall member 37 at the same time.

Due to the simultaneous progress of the arcuate movement and the sliding down, the distance L1 between the tip corner S and the center of gravity G2 is reduced, and in proportion to this, the arcuate movement of the cap nut 1 is accelerated. go. In other words, when the simultaneous movement is started, the circular movement is reliably performed and accelerated. In addition, in FIG. 3(D), since the center of gravity G2 exceeds the tip corner portion S, the cap nut 1 is more likely to be displaced in an arc. This exceeded state is indicated by L2.

Finally, the state shown in FIG. 3(C) is obtained. That is, when the opening edge of the screw hole 3 is received by the tapered portion 11 and the supply rod 14 is retracted, the movable electrode advances, the welding current is applied, and the welding projection 12 is welded to the steel plate component 8 .

It should be noted that, instead of the various air cylinders described above, it is also possible to adopt an electric motor that outputs forward/backward movements. It is also possible to replace the various permanent magnets described above with electromagnets.

Operations such as the forward/backward movement of the supply rod and the permanent magnets described above can be easily performed by commonly employed control methods. Predetermined operation can be ensured by combining an air switching valve that operates with a signal from a control device or a sequence circuit, or a sensor that emits a signal at a predetermined position of the air cylinder and transmits it to the control device.

The effects of the embodiment described above are as follows.

The feed rod 14 advances, and the advance of the feed rod 14 is stopped just before the guide pin 7 or at the point where the tip of the guide pin 7 is slightly inserted into the screw hole 3 . At the same time, the attractive force of the permanent magnet 16 to the cap nut 1 is extinguished, and by this disappearance, the cap nut 1 in the tilted posture moves in the vertical direction while drawing an arc locus. It moves while rubbing against the tip corner S of the wall member 37 .

In this manner, the movement of the cap nut 1 along an arc locus and the rubbing of the outer surface of the nut body 2 against the tip corner S of the wall member 37 are performed simultaneously. Since the contact point between the outer surface of the nut body 2 and the tip corner S of the wall member 37 relatively approaches the position of the center of gravity G2 of the cap nut 1, that is, the distance L1 is reduced, the contact point is centered. The cap nut 1 is smoothly displaced in an arc, and the fitting of the screw hole 3 with the guide pin 7 is achieved reliably.

When the plate thickness of the cover member 4 is reduced to reduce its mass, and the center of gravity position G2 approaches the nut body 2 side, as the rubbing movement progresses, a position L2 shown in FIG. Then, the center of gravity position G2 is located forward of the tip corner S of the wall member 37 when viewed in the central axis direction of the supply rod 14 . In such a case, the arcuate displacement of the cap nut 1 is more likely to be accelerated, and the supply to the guide pin 7 is ensured.

If the outer surface of the nut body 2 does not move while rubbing against the tip corner S of the wall member 37, the distance L1 between the tip corner S of the wall member 37 and the center of gravity position G2 of the cap nut 1 increases, As a result, the force component that moves the cap nut 1 in the vertical direction in an arc motion is reduced, and the cap nut 1 is less likely to fall from the holding recess 36 . However, as the cap nut 1 is displaced toward the posture in the vertical direction, the change in posture of the cap nut 1 in the arc direction is promoted by combining the above-mentioned rubbing displacement. That is, since the distance L1 between the tip corner portion S of the wall member 37 and the center of gravity position G2 of the cap nut 1 is reduced, the posture of the cap nut 1 is easily changed in the arc direction.

Since the center of gravity position G2 of the cap nut 1 exists in the cover member 4, the holding stability of the cap nut 1 in the holding recess 36 is lowered. 37 and a sub-retaining surface 39 surrounding the hemispherical portion of the cover member 4 are formed. The holding of the cover member 4 by 39 is ensured by the attractive force of the permanent magnet 16 . Therefore, even if the center of gravity position G2 of the cap nut 1 exists in the cover member 4, the cap nut 1 does not shift within the holding recess 36 when the supply rod advances, and is securely held in the holding recess 36. and stable operation of the supply rod 14 can be achieved. In particular, since the nut body 2 and the cover member 4 are held at two points, the main holding surface 38 and the sub-holding surface 39, the holding stability of the cap nut 1 is improved. Furthermore, when the angle of inclination of the supply rod 14 approaches the vertical direction, the cap nut 1 is more likely to escape from the holding recess 36. However, by holding the above-mentioned two points, even when the angle of inclination of the supply rod 14 changes, Stable nut retention is achieved.

A passage notch 42 through which the cap nut 1 passes when shifting from the supply rod 14 to the guide pin 7 is formed in an open state on the side surface (flat surface 30) of the supply rod 14 opposite to the direction of inclination. It also has an arcuate cover member passage portion 43 through which the hemispherical portion of the cover member 4 passes, and a nut body passage portion 44 through which the nut body 2 passes. Therefore, when the cap nut 1 moves along an arc toward the guide pin 7, the cover member 4 reliably passes through the cover member passing portion 43, ensuring operational stability. In particular, since the outer surface of the nut body 2 is displaced from the tip corner portion S of the wall member 37, the cover member 4 does not interfere with the cover member passing portion 43, and a reliable supply operation can be obtained.

The effects of the feeding method embodiment are also the same as the feeding rod embodiment.

As described above, according to the device of the present invention, the cap nut held by the supply rod is moved in a circular arc and is rubbed against the tip of the supply rod in combination to reliably supply the guide pin of the fixed electrode. do. Therefore, it can be used in a wide range of industrial fields, such as automobile body welding processes and home electric appliance sheet metal welding processes.

1 cap nut 2 nut body 3 screw hole 4 cover member 6 fixed electrode 7 guide pin 8 steel plate part 14 supply rod 16 permanent magnet 36 holding recess 37 wall member 38 main holding surface 39 sub-holding surface 40 concave surface 41 concave surface 42 passage notch 43 Cover member passing portion 44 Nut main body passing portion S Tip corner L1 Distance between tip corner S and center of gravity G2 100 Feeding device

Claims (2)

A cap nut with a threaded hole opened on one side of the nut body and a hemispherical cover member coupled to the other side, with the center of gravity positioned in the cover member, is used as a guide pin for a fixed electrode for electric resistance welding. that supplies
A holding recess for accommodating the cap nut is formed at the tip of the forward/backward actuating supply rod arranged in an inclined posture,
The holding recess is formed with a main holding surface formed of a wall member surrounding the nut body and a sub-holding surface surrounding the hemispherical portion of the cover member,
A passage notch through which the cap nut passes when shifting from the supply rod to the guide pin is formed in an open state on the side surface opposite to the direction of inclination of the supply rod, and the hemispherical shape of the cover member. has an arc-shaped cover member passage portion through which the portion passes and a nut body passage portion through which the nut body passes,
a permanent magnet is provided on the supply rod so as to be able to move back and forth so that the outer portion of the nut body is in contact with the main holding surface and the hemispherical portion of the cover member is kept in contact with the sub-holding surface;
When the feed rod advances, the threaded hole stops just before the guide pin or at a point where the tip of the guide pin is slightly inserted into the threaded hole. The attraction force of the magnet is extinguished, and as a result of this extinguishing, the cap nut in an inclined posture moves in the vertical direction while drawing an arc locus. to reduce the distance between the center of gravity of the cap nut housed in the holding recess and the tip corner of the wall member, viewed in the direction of the center axis of the supply rod, so that the tip corner is Configured so that the circular arc displacement of the centered cap nut is performed smoothly ,
Reduction of the distance between the center of gravity position and the tip corner of the wall member causes the outer portion of the nut body to come into contact with the main retaining surface and the hemispherical portion of the cover member to contact the sub retaining surface due to the attractive force of the permanent magnet. From the center of gravity position set by the contact state, the cap nut moves in an arc in the vertical direction caused by the disappearance of the attractive force of the permanent magnet, and the outer surface of the nut body descends while rubbing the tip corner of the wall member. A supply rod for a cap nut, characterized in that it is displaced to a set center-of-gravity position by A cap nut with a threaded hole opened on one side of the nut body and a hemispherical cover member coupled to the other side, with the center of gravity positioned in the cover member, is used as a guide pin for a fixed electrode for electric resistance welding. that supplies
A holding recess for accommodating the cap nut is formed at the tip of the forward/backward actuating supply rod arranged in an inclined posture,
The holding recess is formed with a main holding surface formed of a wall member surrounding the nut body and a sub-holding surface surrounding the hemispherical portion of the cover member,
A passage notch through which the cap nut passes when shifting from the supply rod to the guide pin is formed in an open state on a lateral side surface opposite to the direction of inclination of the supply rod, and the hemispherical shape of the cover member. has an arc-shaped cover member passage portion through which the portion passes and a nut body passage portion through which the nut body passes,
preparing a supply rod provided with a permanent magnet capable of moving back and forth so that the outer portion of the nut body is in contact with the main holding surface and the semispherical portion of the cover member is kept in contact with the sub-holding surface;
When the feed rod advances, the threaded hole stops just before the guide pin or at a point where the tip of the guide pin is slightly inserted into the threaded hole. The attraction force of the magnet is extinguished, and as a result of this extinguishing, the cap nut in an inclined posture moves in the vertical direction while drawing an arc locus. to reduce the distance between the center of gravity of the cap nut housed in the holding recess and the tip corner of the wall member, viewed in the direction of the center axis of the supply rod, so that the tip corner is Circular displacement of the centered cap nut is performed smoothly,
Reduction of the distance between the center of gravity position and the tip corner of the wall member causes the outer portion of the nut body to come into contact with the main retaining surface and the hemispherical portion of the cover member to contact the sub retaining surface due to the attractive force of the permanent magnet. From the center of gravity position set by the contact state, the cap nut moves in an arc in the vertical direction caused by the disappearance of the attractive force of the permanent magnet, and the outer surface of the nut body descends while rubbing the tip corner of the wall member. A supply method for a cap nut supply rod, characterized in that the supply rod is displaced to a set center-of-gravity position by

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