JP2012066294A - Horizontal type automatic welding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a horizontal type automatic welding apparatus capable of correctly and reliably butting both ends in the circumferential direction of a workpiece bent in a cylindrical shape to each other, easily taking out the welded workpiece, preventing wastage of a mandrel and clamp plates or the like, damages of the workpiece or the like when taking out the workpiece, and freely setting the lowering position of the clamp plates according to the thickness of the workpiece.SOLUTION: In the horizontal type automatic welding apparatus, both ends in the circumferential direction of a cylindrical workpiece W supported by a mandrel 2 are clamped in a butted condition by a clamp mechanism 6. The clamp mechanism 6 has a pair of opposing clamp plates 18 which are urged downwardly by an elastic body 19, and abutted in an inclined posture on upper surfaces of both ends in the circumferential direction of the workpiece W. The pair of clamp plates 18 are elevated/lowered with respect to the mandrel 2 by a motor-drive type driving device 21.

Description

  The present invention supports a workpiece formed by bending a metal plate such as a stainless steel plate or a steel plate into a cylindrical shape by a horizontal mandrel, and clamps both ends in the circumferential direction of the workpiece on a back bar provided on the mandrel. In connection with the improvement of the horizontal type automatic welding equipment which clamps the butt part of the workpiece in this state and butt welds the butt part of the workpiece to produce a pipe or drum, in particular, the clamp width (a pair of clamp plates of the clamp mechanism) Even when butt welding is performed on thin plate workpieces (workpieces with a thickness of 0.1 mm to 0.4 mm) with a narrow gap between the clamp plates when the workpiece is clamped) It is possible to check the workpiece accurately, and to ensure that both ends of the workpiece are brought into close contact with each other when the workpiece is clamped by the clamping mechanism. The clamp can be clamped, and the welded workpiece can be easily removed from the mandrel, and the wear of the mandrel and the clamp plate of the clamp mechanism, the damage and deformation of the workpiece can be prevented when the workpiece is removed. The present invention also relates to a horizontal automatic welding apparatus in which the lowering position of the clamp plate of the clamp mechanism can be freely set according to the thickness of the workpiece.

  Conventionally, as an apparatus for producing a pipe by butt welding both ends in a circumferential direction of a workpiece made of a metal plate bent into a cylindrical shape, for example, a horizontal automatic welding apparatus previously developed by the present applicant is known. (For example, see Patent Document 1 and Patent Document 2).

  That is, as shown in FIG. 17, the horizontal automatic welding apparatus includes a horizontal mandrel 50 supporting a workpiece W bent into a cylindrical shape, a long back bar 51 provided on the upper surface of the mandrel 50, A center positioning mechanism (not shown) that is provided on the mandrel 50 and positions the end surface of the work W so that both circumferential ends of the work W are abutted on the slit-like grooves of the back bar 51, and an upper position of the mandrel 50 The clamp mechanism 52 of the tube clamp system that clamps on the back bar 51 in a state where both circumferential ends of the workpiece W are butted together, and the mandrel 50 are disposed at a position above the butted portion of the workpiece W. The work W set on the mandrel 50 is composed of a TIG welding apparatus (not shown) provided with a welding torch 53 and the like for welding. Both ends in the circumferential direction are positioned by the center positioning mechanism, and both ends in the circumferential direction of the positioned workpiece W are butt-fixed on the back bar 51 by the clamp mechanism 52, and the butt portions are butt-welded by a TIG welding apparatus. It is made to join.

  Further, as shown in FIG. 17, the tube clamp type clamp mechanism 52 is supported by a frame 54 disposed above the mandrel 50 so as to be swingable in the vertical direction via a hinge 52a, and is arranged in a left-right direction. The clamp plate 52b, the tension spring 52c that urges the left and right clamp plates 52b upward, the air tube 52d that expands by supplying compressed air and pushes the left and right clamp plates 52b downward, and so on. When compressed air is supplied to expand the air tube 52d, the left and right clamp plates 52b swing downward against the elastic force of the tension spring 52c, and the distal ends of the left and right clamp plates 52b are supported by the mandrel 50. The both ends in the circumferential direction of the workpiece W are in contact with the upper surfaces of both ends in the circumferential direction of the workpiece W and are moved onto the back bar 51. Flop, and also, when stopping the supply of compressed air, swings upward by the elastic force of the spring 52c pulling the left and right clamp plates 52 b, so that the clamped state of the workpiece W is released.

By the way, in order to perform ideal butt welding of the workpiece W, it is necessary to adjust the distance (clamp width) between the left and right clamp plates 52b when clamping the workpiece W according to the thickness of the workpiece W to be butt welded. Generally, when the thickness of the workpiece W is reduced, the interval (clamp width) between the left and right clamp plates 52b is narrowed. When the thickness of the workpiece W is increased, the interval between the left and right clamp plates 52b ( The clamp width is widened.
For example, in the case of a workpiece W having a thickness of 0.1 mm to 0.4 mm (thin plate workpiece W), the distance (clamp width) between the left and right clamp plates 52b is set to 1.0 mm to 3.0 mm. In the case of a workpiece W having a thickness of 0.6 mm to 2.0 mm (thick plate workpiece W), the interval (clamp width) between the left and right clamp plates 52b is set to 4.0 mm to 20 mm.

  In particular, in the case of butt welding a workpiece W having a very small thickness, it is better to make the interval between the left and right clamp plates 52b as narrow as possible. This is because if the distance between the left and right clamp plates 52b is widened, the surface temperature of the workpiece W is likely to be higher than that of the thick workpiece W due to the heat during welding. Because it will cause.

  However, in the conventional horizontal type automatic welding apparatus described above, the clamp mechanism 52 having a structure in which the left and right clamp plates 52b are arranged so as to swing up and down around the hinge 52a attached portion is used. Therefore, when a butt welding is performed on a thin workpiece W having a thickness of 0.1 mm to 0.4 mm, the following problems have occurred.

  For example, when butt-welding a thin workpiece W having a thickness of 0.1 mm to 0.4 mm, in order to prevent thermal distortion during welding, the clamp width of the left and right clamp plates 52b (the left and right clamp plates 52b are The distance between the left and right clamping plates 52b when clamping is reduced to 1.0 mm to 3.0 mm, and welding must be performed.

  However, in the tube clamp type clamp mechanism 52 described above, when the left and right clamp plates 52b swing in the vertical direction, the tips of the left and right clamp plates 52b that face each other draw an arc-shaped locus. Unless the opening / closing stroke (swinging stroke) of 52b is reduced, the ends of the left and right clamping plates 52b interfere with each other when the left and right clamping plates 52b swing upward.

  Therefore, when welding thin workpieces W, when the left and right clamp plates 52b are opened (when the left and right clamp plates 52b swing upward and do not clamp the workpiece W), the left and right clamp plates The distance between the mandrel 50 and the left and right clamp plates 52b is inevitably set in order to avoid the interference between the clamp plates 52b when the left and right clamp plates 52b are opened. Must.

  As described above, in the conventional horizontal automatic welding apparatus using the tube clamp type clamp mechanism 52, when the thin workpiece W is welded, the interval when the left and right clamp plates 52b are opened becomes substantially zero. When the both ends of the workpiece W in the circumferential direction are butted on the back bar 51 provided on the mandrel 50, the butting portion of the workpiece W cannot be seen, and the exact butting work of the workpiece W cannot be performed. There was a problem that the status could not be confirmed.

  Further, in the conventional horizontal automatic welding apparatus, since the space between the mandrel 50 and the left and right clamp plates 52b is narrow, it is extremely difficult to take out the workpiece W when taking out the welded workpiece W (pipe) from the mandrel 50. In addition, the work W rubs the upper surface of the mandrel 50 and the back bar 51 or the lower surface of the left and right clamp plates 52b to accelerate the consumption of the mandrel 50, the back bar 51 and the left and right clamp plates 52b, and the work W is damaged. There was a problem of deformation.

  Further, in the conventional horizontal type automatic welding apparatus, when the left and right clamp plates 52b swing downward and clamp the workpiece W at the tips, the tips of the left and right clamp plates 52b spread in a C shape. When the workpiece W is clamped by the left and right clamp plates 52b, a phenomenon occurs in which the interval between the left and right clamp plates 52b is widened. At this time, a force to open the workpiece W acts on both ends of the workpiece W in the circumferential direction, and a gap may be generated in the butt portion of the workpiece W. Therefore, when the workpiece W is butt-welded in this state, there is a problem that welding defects such as perforations and dents are generated, and the quality of the welded workpiece W (pipe) is remarkably deteriorated.

  In addition, the conventional horizontal automatic welding apparatus pressurizes the left and right clamp plates 52b toward the workpiece W by the expansion of the air tube 52d, but there is a problem that it is difficult to adjust the pressure of the left and right clamp plates 52b. there were.

JP 2003-205369 A JP 2007-021566 A

  The present invention has been made in view of such problems, and the purpose of the present invention is to confirm the state of the butt portion of the workpiece even when performing butt welding of a thin plate workpiece having a narrow clamp width. The workpiece can be accurately matched, and both ends in the circumferential direction of the workpiece can be clamped so that both ends in the circumferential direction of the workpiece are in close contact, and the welded workpiece can be easily taken out. Horizontal automatic welding that prevents the mandrel and clamp plate, etc. from being worn and the workpiece from being damaged and deformed when the workpiece is taken out, but allows the lowering position of the clamp plate to be freely set according to the thickness of the workpiece. To provide an apparatus.

  In order to achieve the above object, a first aspect of the present invention includes a mandrel that is supported by a frame in a horizontal posture and supports a workpiece made of a metal plate bent into a cylindrical shape, and a back provided on the upper surface of the mandrel. A bar and a center positioning mechanism provided on the mandrel for positioning the circumferential end face of the work, and a position above the mandrel, on both sides of the work in the circumferential direction, and onto the back bar In a horizontal type automatic welding apparatus having a clamping mechanism for clamping and a welding apparatus for butt welding a butt portion of a workpiece, the clamping mechanism is disposed in an opposing manner in a posture along the mandrel at a position above the mandrel. A pair of clamp bases and a pair of clamps that are supported by each clamp base so as to be movable up and down and arranged in an opposing manner along the mandrel. The plate and the lower surface of each clamp movable plate are mounted so as to be swingable in the vertical direction in a posture along the mandrel, and are arranged so as to be in contact with the upper surface of both ends in the circumferential direction of the work supported by the mandrel. Elasticity that is interposed between a pair of clamp plates, each clamp movable plate, and each clamp plate, and biases the opposed tip portions of the pair of clamp plates downward to hold the pair of clamp plates in an inclined posture A pair of motor-driven drive devices that are provided between the body, each clamp base, and each clamp movable plate, and that adjust the pressure applied to each clamp plate by moving each clamp movable plate and each clamp plate up and down Each clamp plate is lowered by a driving device, and the tip of each clamp plate comes into contact with the upper surface of both ends in the circumferential direction of the work supported by the mandrel, so that the circumference of the work When both ends in the direction are pressed, it swings upward against the elastic force of the elastic body, and the distance between the tip parts of both clamp plates is narrowed and adjusted to the distance according to the thickness of the workpiece It is characterized by that.

  According to the second aspect of the present invention, the pair of clamp movable plates includes an inner clamp movable plate located on the mandrel side, and an outer clamp movable plate attached to the outer end of the inner clamp movable plate so as to be horizontally movable toward the mandrel side. The clamp plate is swingably attached to the lower surface of the outer clamp movable plate via a hinge, and the gap between the inner clamp movable plate and the outer clamp movable plate is adjusted to the outer clamp movable plate. The adjustment screw is rotatably inserted in the axial direction in a state where it is unmovable, and the screw portion formed at the tip of the adjustment screw is screwed to the outer end of the inner clamp movable plate so as to be movable in the axial direction. It is characterized in that the interval between the tip portions of the pair of clamp plates arranged in an opposing manner can be freely adjusted by rotating the adjustment screw.

  According to a third aspect of the present invention, a pair of motor-driven drive devices are provided between the clamp base and the clamp movable plate, and a ball screw mechanism for moving the clamp movable plate up and down with respect to the clamp base; It consists of a servo motor arranged on the base, a servo motor controller that servo-controls the servo motor, and a transmission mechanism that transmits the rotational motion of the servo motor to the ball screw mechanism, and by controlling the servo motor, The lowering position can be freely set according to the thickness of the workpiece, and the pressing force of the clamp plate can be freely adjusted.

In the horizontal type automatic welding apparatus according to claim 1 of the present invention, a clamp mechanism that clamps on the back bar of the mandrel in a state in which both ends of the workpiece in the circumferential direction are abutted is disposed in an opposing manner above the mandrel. A pair of clamp bases, a pair of clamp movable plates that are supported by each clamp base so as to be movable up and down, and are opposed to each other, and are attached to the lower surface of each clamp movable plate so as to be swingable in the vertical direction. A pair of clamp plates arranged in an opposing manner that can come into contact with the upper surfaces of both ends in the circumferential direction of the work supported by the workpiece, and a pair of clamp plates interposed between each clamp movable plate and each clamp plate Is provided between each clamp base and each movable clamp plate, and moves up and down each movable clamp plate and each clamp plate. The clamp plate is composed of a pair of moving type drive devices, and the clamp plates are elastic bodies when the tip of each clamp plate comes into contact with the upper surface of both ends in the circumferential direction of the work supported by the mandrel and pressurizes the work. Because it is configured to swing upward and resist the elastic force of the clamp plate, the interval between the tip portions of both clamp plates is narrowed and adjusted to the interval according to the thickness of the workpiece, when welding thin plate workpieces, Even when the clamp width of the pair of clamp plates (the interval between the clamp plates when the pair of clamp plates clamps the workpiece) is set narrow, when the clamp plates are released (the pair of clamp plates do not clamp the workpiece) Since the clamp width of the clamp plate is wide when the workpiece is in the state), when the both ends of the workpiece in the circumferential direction are brought into contact with each other on the back bar provided on the mandrel, the workpiece butt portion is visually observed between the clamp plates. , Together with enabling a precise butt working of the workpiece, it is possible to check the status of the butted portion of the workpiece.
Further, in the horizontal automatic welding apparatus according to claim 1 of the present invention, when the tip of each clamp plate comes into contact with the upper surface of both ends in the circumferential direction of the work supported by the mandrel, Since both clamp plates swing upwards against the elastic force of the elastic body and the distance between the tip parts of both clamp plates is narrowed, the elastic force of the elastic body when the workpiece is pressed by the clamp plate This causes a force to close both ends of the workpiece in the circumferential direction, and the ends of the workpiece in the circumferential direction come into close contact with each other. As a result, high-quality pipes and drums free from welding defects such as perforations and dents can be obtained. Can be produced.
Furthermore, in the horizontal automatic welding apparatus according to claim 1 of the present invention, since the pair of clamp plates is configured to move up and down with respect to the mandrel by the pair of driving devices, the distance between the mandrel and the pair of clamp plates is increased. When removing a welded workpiece (pipe or drum) from the mandrel, the workpiece can be easily removed, and the workpiece can rub the upper surface of the mandrel, the back bar, and the lower end of the tip of the left and right clamp plates. As a result, it is possible to prevent the mandrel, the back bar and the left and right clamp plates from being consumed, and the workpiece to be damaged and deformed.

In addition to the above effects, the horizontal automatic welding apparatus according to claims 2 and 3 of the present invention can further exhibit the following excellent effects.
That is, in the horizontal type automatic welding apparatus according to claim 2 of the present invention, the pair of clamp movable plates can move horizontally to the mandrel side on the inner clamp movable plate located on the mandrel side and the outer end of the inner clamp movable plate. The clamp plate is attached to the lower surface of the outer clamp movable plate via a hinge so as to be swingable in the vertical direction, and the inner clamp movable plate and the outer clamp movable plate are mounted on the outer clamp movable plate. The adjustment screw that adjusts the gap between the adjustment screw is rotatably inserted in the axial direction, and the screw portion formed at the tip of the adjustment screw is moved in the axial direction to the outer end portion of the inner clamp movable plate. Since it is configured to be able to adjust the distance between the tip portions of the pair of clamp plates arranged in an opposing manner by screwing the adjusting screws and rotating the adjusting screw, Can be of even thickness is changed, it is adjusted easily so that an optimum interval according to distance between the pair of clamping plates to a thickness of the workpiece. In addition, the adjustment screw that adjusts the distance between the pair of clamp plates is inserted into the outer clamp movable plate in an embedded state and does not protrude to the outside, so the adjustment screw is inadvertently turned and the interval between the clamp plates changes. There is nothing.

Further, in the horizontal type automatic welding apparatus according to claim 3 of the present invention, a pair of motor-driven drive devices are provided between the clamp base and the clamp movable plate, and the clamp movable plate is moved up and down with respect to the clamp base. Each of which includes a ball screw mechanism, a servo motor disposed on the clamp base, a servo motor control unit that servo-controls the servo motor, and a transmission mechanism that transmits the rotational motion of the servo motor to the ball screw mechanism. As a result, the lowering position of the clamp plate can be freely set according to the thickness of the workpiece, and the pressing force of the clamp plate can be adjusted freely, making it easier to perform workpiece butt work. At the same time, the both ends of the workpiece in the circumferential direction can be more accurately matched.
For example, a pair of clamp plates are held lightly enough to move the position of the preload position (the gap of the workpiece thickness + α, that is, a pair of clamp plates supported by the mandrel in the circumferential direction of the workpiece onto the back bar. When the workpiece is lowered to the position), both ends of the workpiece in the circumferential direction are guided by the clamp plate and the back bar of the mandrel, so that one end of the workpiece in the circumferential direction can easily abut against the center plate of the center positioning mechanism. In addition, the other end in the circumferential direction of the workpiece can be abutted without overlapping with one end in the circumferential direction of the workpiece, and the both ends of the workpiece in the circumferential direction can be accurately and reliably abutted.

1 is a perspective view of a horizontal automatic welding apparatus according to an embodiment of the present invention. It is an enlarged front view of a horizontal type automatic welding apparatus. It is a side view of a horizontal type automatic welding apparatus similarly. It is a top view of a horizontal type automatic welding apparatus similarly. The mandrel is shown, (A) is a partially omitted plan view of the mandrel, and (B) is a partially omitted side view of the mandrel. It is a side part of the principal part of a mandrel. It is a vertical front view of a mandrel. It is a front view of a clamp mechanism and a mandrel. It is a top view of a clamp mechanism. It is a side view of a clamp mechanism and a mandrel. It is a perspective view of the right side part of a clamp mechanism which shows a clamp mechanism. FIG. 10 is an enlarged sectional view taken along line II in FIG. 9. FIG. 10 is an enlarged cross-sectional view of the roll line of FIG. 9. FIG. 10 is an enlarged sectional view taken along the line ha-ha in FIG. 9. FIG. 10 is an enlarged sectional view of the knee line in FIG. 9. It is operation | movement explanatory drawing of a horizontal type automatic welding apparatus. It is the schematic of the principal part of the horizontal type automatic welding apparatus using the conventional clamp mechanism.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 to 4 show a horizontal automatic welding apparatus according to an embodiment of the present invention. The horizontal automatic welding apparatus includes a workpiece W formed by bending a metal plate such as a stainless steel plate or a steel plate into a cylindrical shape. Pipes and drums are produced by butt welding both ends in the circumferential direction, especially when butt welding a thin plate workpiece W (work W having a thickness of 0.1 mm to 0.4 mm) with a narrow clamp width. Even if there is a workpiece W, it is possible to confirm the state of the workpiece W butt portion during the butt work, and to accurately butt the workpiece W. Also, in the circumferential direction of the workpiece W so that both ends of the workpiece W are in close contact with each other. Both ends can be clamped, and the welded workpiece W (pipe or drum) can be easily taken out. At the time of taking out the workpiece W, the mandrel 2 is consumed, the back bar 3 is consumed, the clamping mechanism 6 Consumption of the clamp plate 18 can be prevented respectively damage and deformation of the workpiece W, deer, is obtained as the lowered position of the clamp plate 18 can be freely set according to the thickness of the workpiece W.

That is, as shown in FIGS. 1 to 4, the horizontal automatic welding apparatus includes a frame 1 and a long mandrel 2 that is supported by the frame 1 so as to be rotatable in a cantilevered state and supports a workpiece W. Are attached to the outer surface of the mandrel 2 at intervals of 180 degrees, and are used for welding a thin plate workpiece W (referring to a workpiece W having a thickness of about 0.1 mm to 0.4 mm). A long back bar 3 for a thick plate used when welding the back bar 3 and a workpiece W for a thick plate (referring to a workpiece W having a thickness of about 1 mm to 3 mm), and the mandrel 2, the workpiece W A pair of center positioning mechanisms 4 for positioning the end face of the workpiece W so that both ends in the circumferential direction of the plate abut each other on the thin plate back bar 3 and the thick plate back bar 3, and the lower position of the mandrel 2 Arranged in the The workpiece support device 5 that supports a workpiece W having a large diameter or a long workpiece W set on the dorel 2 in a horizontal posture, and a state in which both circumferential ends of the workpiece W are abutted with each other. The clamp mechanism 6 that clamps onto the back bar 3 and a welding device 7 (in this example, a TIG welding device) that is disposed above the mandrel 2 and butt welds the butt portion of the workpiece W. .
This horizontal type automatic welding apparatus has a substantially symmetrical structure so that work can be performed from either the left or right position, and operation switches 8 for operating the clamp mechanism 6 are provided on both side surfaces of the frame 1, respectively. Yes.

Specifically, as shown in FIGS. 1 to 4, the frame 1 is provided on a box-shaped main body frame 1a and an upper portion of the main body frame 1a, and is horizontally oriented forward (left side in FIG. 3) from the main body frame 1a. And a base frame 1c provided at the lower part of the main body frame 1a and protruding in a horizontal posture in the same direction as the upper frame 1b and installed on the floor via casters and adjusters. The main body frame 1a accommodates a welding power source, a welding gas cylinder such as argon gas, and a compressed air supply source such as a compressor (both not shown).
Further, on the upper surface of the upper frame 1b, a turning arm 10 having a touch panel type operation panel 9 for setting welding conditions, electrode positions and the like of the welding device 7 is rotatably disposed at the tip portion. Operation switches 8 for the clamp mechanism 6 are provided on both side surfaces of the frame 1b.
Further, the portion of the upper frame 1b that protrudes from the main body frame 1a is composed of two long box-shaped members whose bottom surfaces are open, and these two long box-shaped members are along the mandrel 2 at a position obliquely above the mandrel 2. It is arranged in an opposing manner in the posture.

As shown in FIGS. 3 and 5, the mandrel 2 includes a mandrel main body 2A formed of a metal material such as an aluminum alloy into a substantially rectangular prism shape in cross section, and a tip of the mandrel main body 2A (left end in FIG. 5). And a mandrel fitting 2B having a mandrel pin 2a that is removably inserted into a mandrel receiver 11 provided at the tip of the upper frame 1b, and a rotating shaft at the base end (right end in FIG. 5) of the mandrel body 2A. The cross-sectional shape attached via the metal fitting 2C is composed of a mandrel rotating shaft 2D having a circular shape. The mandrel rotating shaft 2D is supported by the main body frame 1a of the frame 1 in a cantilevered manner and rotatably about its axis. The back bar 3 for thick plate or the back bar 3 for thick plate is positioned so as to face right above.
Further, as shown in FIGS. 6 and 7, a long back bar 3 for a thin plate and a long back bar 3 for a thick plate are detachably fitted to both sides of the short side of the mandrel body 2A. The mounting grooves 2b are formed along the longitudinal direction of the mandrel 2, respectively. A gas groove 2c through which a shielding gas such as argon gas flows is formed along the longitudinal direction of the mandrel 2 on the bottom surfaces of both the mounting grooves 2b, and a recess provided with a drive unit for the center positioning mechanism 4 described later. 2d is formed at regular intervals in the longitudinal direction of the mandrel 2, respectively. Recesses 2 d formed on the bottom surfaces of both mounting grooves 2 b of the mandrel 2 are formed in the state of being bent over the longitudinal direction of the mandrel 2 and in the vicinity of the center of the mandrel 2.
Further, compressed air is supplied to the gas supply port 2e for supplying a shielding gas such as argon gas to the gas groove 2c and the piston hole 2g formed in the bottom surface of the recess 2d on both long side surfaces of the mandrel body 2A. A compressed air supply port 2d is formed.

  The mandrel 2 has a mandrel bracket 2B on the front end side supported by the mandrel receiver 11 when the work W is being butted or welded, and the mandrel 2 is supported by the main body frame 1a and the mandrel receiver 11. .

  The mandrel receiver 11 is configured to swing from the horizontal position to the vertical position by the rotary actuator 11a, and the mandrel receiver 11 is rotated from the horizontal position to the vertical position to support the mandrel receiver 11. By inserting the mandrel pin 2a of the mandrel 2 into the hole, the tip of the mandrel 2 can be supported.

As shown in FIG. 7, the thin plate back bar 3 and the thick plate back bar 3 are each a pair of symmetrical back bar pieces formed of copper material in the shape of a long rectangular column having a substantially rectangular cross section. 3a, and is removably fitted into the mounting groove 2b of the mandrel 2 so that a slit-like groove 3b is formed between the pair of backbar pieces 3a with the pair of backbar pieces 3a facing each other. Yes.
Each back bar 3 fitted in the mounting groove 2b of the mandrel 2 is fixed to the mandrel 2 in the axial direction by fastening and fixing the pair of back bar pieces 3a to the mandrel 2 side with a plurality of bolts. It is attached with.

Each of the back bars 3 absorbs excess heat when butt-welding both ends in the circumferential direction of the workpiece W to prevent the beads from being melted and perforated, the workpiece W being thermally strained, and the like. A shield gas is allowed to flow on the back side of the butt portion to prevent oxidation of the welded portion.
The slit-shaped groove 3b formed between the pair of back bar pieces 3a is used for inserting the center plate 12 of the center positioning mechanism 4 in a loosely fitted state and flowing a shield gas such as argon gas. .

  In this embodiment, the thin plate back bar 3 attached to one short side of the outer surface of the mandrel 2 has a slit-like groove 3b having a width of 1.0 mm, and the mandrel 2 The thick plate back bar 3 attached to the other short side of the outer surface has a slit-like groove 3b having a width of 1.2 mm.

  In each of the center positioning mechanisms 4, the circumferential end surfaces of the workpiece W are abutted on the slit-like groove 3b of the thin plate back bar 3 and on the slit-like groove 3b of the thick plate back bar 3, respectively. As shown in FIG. 7, the end face of the workpiece W is positioned so as to be inserted into the slit-like groove 3 b of the back bar 3 so as to be movable in the radial direction of the mandrel 2. The center plate 12 and a plurality of drive units 13 having a cylinder structure provided on the mandrel 2 at regular intervals in the longitudinal direction and moving the center plate 12 in the radial direction of the mandrel 2 are respectively configured.

That is, each center plate 12 is inserted into the slit-like grooves 3b of the thin plate back bar 3 and the thick plate back bar 3 in a loosely fitted state and movably in the radial direction of the mandrel 2, The front end portion can protrude outward from the upper surface of the back bar 3, and the end surface of the workpiece W is in contact with the side surface of the front end portion.
These center plates 12 are set so that the thickness thereof is thinner than the width of the slit-like groove 3 b of the back bar 3. Therefore, when the center plate 12 is inserted into the slit-like groove 3 b of the back bar 3, a slit-like gap through which a shielding gas such as argon gas flows is formed between the side surface of the center plate 12 and the back bar 3. become. In this embodiment, the thickness of the center plate 12 is set to 0.5 mm. Each center plate 12 has a shape divided into three in the longitudinal direction.

  On the other hand, each drive unit 13 is provided in the state where it lies over the longitudinal direction of the mandrel 2 and is provided in the vicinity of the center of the mandrel 2, and is fitted into the recess 2 d of the mandrel 2 so as to be movable in the radial direction of the mandrel 2. The support plate 13a on which the center plate 12 is supported and fixed by bolts, and the piston plate 2g formed in the bottom surface of the concave portion 2d of the mandrel 2 are slidable in the radial direction of the mandrel 2 The inserted piston 13b is interposed between the back bar 3 and the support base 13a. The support base 13a is urged toward the center of the mandrel 2 so that the tip of the center plate 12 is shaped like a slit in the back bar 3. It is composed of a return compression spring 13c located in the groove 3b, and forms compressed air from a compressed air supply source (not shown) in the mandrel 2. When the compressed air supply port 2f supplies the piston hole 2g, the piston 13b, the support 13a and the center plate 12 move in the radial direction of the mandrel 2 against the elastic force of the compression spring 13c, and the tip of the center plate 12 Protrudes outward from the upper surface of the back bar 3, and when the supply of compressed air is stopped, the elastic force of the compression spring 13c causes the piston 13b, the support 13a and the center plate 12 to move toward the center of the mandrel 2, The front end of the plate 12 is accommodated in the slit-shaped groove 3b.

  In addition, since each drive part 13 of a pair of center positioning mechanism 4 is provided in the vicinity of the center part of the mandrel 2 in the state where it crawls over the longitudinal direction of the mandrel 2, the length of the long side of the mandrel 2 The mandrel 2 can be reduced in weight.

  The workpiece support device 5 supports the workpiece W in a horizontal posture when welding a workpiece W having a large diameter or a workpiece having a long length, and is positioned below the mandrel 2 as shown in FIGS. An electric lifter 14 provided on the base frame 1c and provided with a rectangular table 14a that can be moved up and down and a cover 14b having a bellows structure that covers a lower space of the table 14a, and an upper surface of the table 14a of the lifter 14. It is comprised from the workpiece | work receiving roller 15 which supports the lower surface of the workpiece | work W of a horizontal attitude | position.

  Further, the work receiving roller 15 includes two long ball roller receivers 15a arranged in an opposing manner in a posture along the mandrel 2 on the upper surface of the table 14a, and the mandrel 2 on the upper surface of both ball roller receivers 15a. A plurality of ball rollers 15b mounted at regular intervals and having 360 ° rotatable balls, and the ball rollers 15b arranged in two rows along the mandrel 2 contact the lower surface of the outer peripheral surface of the workpiece W. The work W is supported from the lower surface side.

  As shown in FIGS. 8 to 15, the clamp mechanism 6 includes a pair of clamp bases 16 that are formed in a long plate shape with a metal material and are disposed in an upper position of the mandrel 2 so as to face each other in a posture along the mandrel 2. A pair of clamp movable plates 17 that are supported by each clamp base 16 so as to be movable up and down, and are arranged in an opposing manner along the mandrel 2, and a vertical direction in a posture along the mandrel 2 on the lower surface of each clamp movable plate 17. A pair of clamp plates 18 that are swingably attached to each other and can be brought into contact with the upper surfaces of both ends in the circumferential direction of the work W supported by the mandrel 2, each clamp movable plate 17, and each clamp plate 18, elastic bodies 19 that are respectively interposed between the pair of clamp plates 18 and bias the opposing tip portions of the pair of clamp plates 18 downward to hold the pair of clamp plates 18 in an inclined posture; The clamp movable plate 17 is provided between the clamp base 16 and the clamp movable plate 17, and is provided between the clamp base 16 and the clamp movable plate 17. The movable plate 17 and each clamp plate 18 are moved up and down to form a pair of motor-driven drive devices 21 that adjust the pressure applied to each clamp plate 18. Each of the clamp plates 18 is lowered by the drive device 21. When the tip ends of the clamp plates 18 come into contact with the upper surfaces of both ends in the circumferential direction of the workpiece W supported by the mandrel 2 and pressurize both ends in the circumferential direction of the workpiece W, the elasticity of the elastic body 19 It is configured such that it swings upward against the force, and the interval between the tip portions of both clamp plates 18 is narrowed and adjusted to a predetermined interval (clamp width according to the thickness of the workpiece W).

Therefore, the clamp mechanism 6 is capable of clamping even when the clamp width of the pair of clamp plates 18 during welding (the interval between the clamp plates 18 when the pair of clamp plates 18 clamps the workpiece W) is set narrow. When the plate 18 is opened (when the pair of clamp plates 18 are not clamping the workpiece W), the clamp width of the clamp plate 18 is widened. When abutting, the abutting portion of the workpiece W can be visually observed from between the clamp plates 18, the workpiece W can be accurately abutted, and the state of the abutting portion of the workpiece W can be confirmed.
For example, when a thin plate workpiece W having a thickness of 0.1 mm to 0.4 mm is butt welded, even if the clamp width of the pair of clamp plates 18 at the time of welding is 1.0 mm to 2.0 mm, the clamp plate When 18 is opened, the clamp width of the pair of clamp plates 18 is as wide as 3.0 mm to 5.0 mm.

As shown in FIG. 8, the pair of clamp bases 16 are mounted in a horizontal state on the lower surface of the upper frame 1 b so as to close the lower surface opening of the upper frame 1 b, and are positioned along the mandrel 2 above the mandrel 2. It becomes the appearance arranged in the opposite form.
A safety cover 22 that covers the clamp movable plate 17 and the clamp plate 18 from the outside is attached to the outer end face of each clamp base 16. Each safety cover 22 has an operation hole 22a so that an adjustment screw 26 for adjusting the distance between the pair of clamp plates 18 can be rotated.

As shown in FIGS. 12 and 13, the pair of clamp movable plates 17 is formed in a long plate shape with a metal material and is formed in a prismatic shape with a metal material and an inner clamp movable plate 17a located on the mandrel 2 side. A plurality of upper and lower guide shafts, each of which is composed of an outer clamp movable plate 17b attached to the outer end portion of the inner clamp movable plate 17a so as to be horizontally movable toward the mandrel 2 side. 23 is inserted into a plurality of linear bushes 24 attached to the clamp base 16 so as to be movable up and down, and is supported by the clamp base 16 on the lower surface side of the clamp base 16 so as to be movable up and down.
Further, each outer clamp movable plate 17b is slidably supported by a plurality of guide shafts 25 planted in a horizontal posture orthogonal to the mandrel 2 on the outer end surface of the inner clamp movable plate 17a and horizontally moved to the mandrel 2 side. The distance between the inner clamp movable plate 17a and the outer clamp movable plate 17b and the distance between the pair of clamp plates 18 are adjusted by rotating the two adjusting screws 26 provided on the outer clamp movable plate 17b. It can be done.

That is, as shown in FIG. 14, each adjustment screw 26 is inserted into the outer clamp movable plate 17b by two parallel retaining pins 27 so as to be rotatable and non-movable in the axial direction. A screw portion formed at the tip end portion of 26 is screwed to the outer end portion of the inner clamp movable plate 17a so as to be movable in the axial direction.
Therefore, by rotating each adjustment screw 26, each outer clamp movable plate 17b moves horizontally with respect to each inner clamp movable plate 17a, and the interval between each inner clamp movable plate 17a and each outer clamp movable plate 17b is increased. While being able to adjust, the space | interval of the clamp plate 18 attached to each outer clamp movable plate 17b can also be adjusted.
A compression coil spring 28 is provided between the head of each adjustment screw 26 and the outer end surface of the inner clamp movable plate 17a so that the adjustment screw 26 does not loosen.

As shown in FIG. 8, the pair of clamp plates 18 are formed in a long plate shape with a copper material, and opposite inner portions are bent obliquely downward, and a long structure is formed on the lower surface of the outer clamp movable plate 17b. A hinge 29 is attached so as to be swingable in the vertical direction.
Each clamp plate 18 is moved downward by a plurality of elastic bodies 19 (compression coil springs) interposed between the inner end of the inner clamp movable plate 17a and the clamp plate 18, as shown in FIGS. The inner end of the clamp plate 18 is elastically brought into contact with the upper surfaces of both ends in the circumferential direction of the workpiece W. Each elastic body 19 is housed in a plurality of housing holes 17a ′ formed at regular intervals in the inner portion of the inner clamp movable plate 17a, and has an elongated shape that closes the upper opening of each housing hole 17a ′. The retaining plate 30 prevents the retaining hole 17a 'from coming off.
Further, as shown in FIG. 15, each clamp plate 18 is controlled to swing downward by a plurality of pin-structure stoppers 20 provided at regular intervals on the inner side of the clamp movable plate 17. Each stopper 20 is inserted in a plurality of through holes 17 a ″ formed in the inner part of the pair of clamp movable plates 17 in a loosely fitted state and prevented from being pulled downward, and a lower end portion thereof is inserted into the clamp plate 18. It is in a connected state.
Since each clamp plate 18 is attached to the outer clamp movable plate 17b, the clamps facing each other are changed by rotating the adjustment screw 26 to change the distance between the inner clamp movable plate 17a and the outer clamp movable plate 17b. The distance between the tip portions of the plate 18 can be adjusted.

  The pair of motor-driven drive devices 21 are provided between the clamp base 16 and the clamp movable plate 17 and move the clamp movable plate 17 up and down with respect to the clamp base 16 as shown in FIGS. A plurality of ball screw mechanisms 31, a servo motor 32 disposed on the clamp base 16, a servo motor control unit (not shown) that servo-controls the servo motor 32, and a transmission that transmits the rotational motion of the servo motor 32 to the ball screw mechanism 31. By controlling the servo motor 32, the lowering position of the clamp plate 18 can be freely set according to the thickness of the workpiece W, and the applied pressure of the clamp plate 18 can be adjusted freely. It is configured to be able to. Each of these driving devices 21 is configured to be housed inside the two long box-shaped members forming the upper frame 1b so as not to get in the way.

Each of the ball screw mechanisms 31 has a vertically mounted ball screw shaft 31a that is rotatably supported by a cylindrical bearing base 34 via a bearing 34a and unmovable in the axial direction. And a ball nut 31b that is fixed to the upper surface of the inner clamp movable plate 17a of the clamp movable plate 17 and into which the ball screw shaft 31a is screwed. When the ball screw shaft 31a rotates forward and backward, the ball nut 31b that is prevented from rotating is formed. The clamp movable plate 17 is moved up and down along the ball screw shaft 31 a to move the clamp movable plate 17 up and down relative to the clamp base 16.
In this embodiment, the ball screw mechanism 31 is provided with each clamp base 16 and each clamp movable plate 17 so that the long plate-like clamp movable plate 17 can be moved up and down while maintaining a horizontal posture. There are four locations each.

  Each servo motor 32 is attached to a motor bracket 35 fixed to the upper surface of one end of the clamp base 16 and is servo-controlled by a servo motor control unit (not shown).

  Furthermore, each transmission mechanism 33 is rotatably supported in a posture along the clamp base 16 by a plurality of bearing bases 36 fixed to the upper surface of the clamp base 16, and is located near each ball screw mechanism 31 and has one end coupled. A shaft 33 a connected to the servo motor 32 via 37, four worm gears 33 b fitted to the shaft 33 a and positioned in the vicinity of the ball screw shaft 31 a of each ball screw mechanism 31, and the ball screw shaft 31 a of each ball screw mechanism 31. Each of the four worm wheels 33c is fitted to the upper end portion and meshes with the worm gear 33b.

Thus, according to this motor drive type drive device 21, when the servo motor 32 is driven and controlled by the servo motor controller, the rotational force of the servo motor 32 is applied to the ball screw shaft 31 a of the ball screw mechanism 31 by the transmission mechanism 33. As a result, the ball screw shaft 31a is rotated forward or backward by a predetermined angle or a predetermined number of rotations. Then, the clamp movable plate 17 and the clamp plate 18 are moved up and down by the ball screw mechanism 31.
Since this drive device 21 is servo-controlled, the lowering position of both clamp plates 18 can be freely set according to the thickness of the workpiece W, and the applied pressure of each clamp plate 18 can be adjusted freely. be able to.
As a result, the clamp mechanism 6 causes the pair of clamp plates 18 to be in a preload position (the position of the gap between the thickness of the workpiece W + α, that is, both ends of the workpiece W in which the pair of clamp plates 18 are supported by the mandrel 2 in the circumferential direction). Can be lowered to a position where it can be held lightly enough to move onto the back bar 3, and the pair of clamp plates 18 is pressed (the elastic body 19 is compressed to reduce the distance between the pair of clamp plates 18). The pair of clamp plates 18 can be lowered to a position where both ends in the circumferential direction of the workpiece W are firmly pressed against the back bar 3 in a state where both ends in the circumferential direction of the workpiece W are pressed and adhered.

  9 to 11, reference numeral 38 denotes a sensor shaft which is inserted into the clamp base 16 in a loosely-fitted state and stands on the upper surface of the clamp movable plate 17, and 39 is a sensor bracket fixed to the sensor shaft 38. Reference numeral 40 denotes a photosensor which is attached to a sensor rail 41 erected on the upper surface of the clamp base 16 and regulates the upper limit position and the lower limit position of the clamp plate 18.

As shown in FIGS. 1 and 3, the welding device 7 (TIG welding device 7) is disposed on the upper surface of the upper frame 1b so as to be reciprocally movable in the longitudinal direction of the mandrel 2 via two parallel guide rails 42. The traveling platform 43, a welding torch 45 supported by the traveling platform 43 through an arm member 44, allowing a shield gas such as argon gas to flow from the tip, and having a tungsten electrode rod 45a inserted therein. A torch up / down drive device (not shown) comprising a servo motor or the like provided on the table 43 and moving the welding torch 45 up and down, and a welding condition (consumed tungsten electrode rod, arc state, etc.) provided on the traveling table 43 And a monitoring camera (not shown) for confirming the abutting state of the end portion of the workpiece W, and the traveling platform 43 provided between the tungsten electrode rod 45a and the workpiece W before starting welding. An electrode contact detection device (not shown) that facilitates setting and immediately detects a contact accident between the tungsten electrode rod 45a and the workpiece W during welding, and a motor and transmission for reciprocating the traveling platform 43 in the longitudinal direction of the mandrel 2 It comprises a drive device (not shown) composed of a device, and the tip of the welding torch 45 is automatically adjusted in height and supported by the carriage 43 and the cradle 43 when butt welding the butt portion of the workpiece W. The welded torch 45 is linearly moved along the butt portion of the workpiece W at a predetermined speed. The welding device 7 is configured in the same structure as a conventionally known one.
Since the welding device 7 is configured to support the traveling table 43 provided with the welding torch 45 and the like on the two guide rails 42 disposed on the upper surface of the upper frame 1b, the mounting operation is simple. In addition, it is possible to perform stable welding without causing misalignment or meandering even during long-term use with an inexpensive structure.

  Next, a case where a pipe or a drum is manufactured by butt welding both circumferential ends of a workpiece W bent into a cylindrical shape using the horizontal automatic welding apparatus described above will be described.

  The workpiece W is a thin workpiece W obtained by bending a stainless steel plate having a thickness of 0.1 mm to 0.4 mm into a cylindrical shape, or a stainless steel plate having a thickness of 0.6 mm to 2.0 mm having a cylindrical shape. A bent work W is used. Also, the welding conditions such as welding current, arc length, supply amount of shield gas, traveling speed of welding torch 45, tip shape of tungsten electrode rod 45a, etc. are optimum according to the material, plate thickness, width, etc. of workpiece W. Of course, it is set under the conditions.

First, the mandrel 2 is manually rotated according to the thickness of the workpiece W to be butt welded, and the mandrel 2 is rotated so that the back bar 3 corresponding to the thickness of the workpiece W faces directly upward.
For example, when a workpiece W of a thin plate (thickness of 0.1 mm to 0.4 mm) is butt-welded, the mandrel 2 is rotated to rotate the thin plate back bar 3 (a back bar having a narrow slit-shaped groove 3b). Rotate the mandrel 2 so that 3) faces directly above.

  Next, the work W bent into a cylindrical shape is inserted into the mandrel 2 and the tip of the mandrel 2 is supported by the mandrel receiver 11 to prevent the elongate mandrel 2 from being bent. The center plate 12 of the center positioning mechanism 4 located on the upper surface side of the center plate 12 is raised by the drive unit 13 so that the front end portion (upper end portion) of the center plate 12 protrudes upward from the upper surface of the back bar 3.

  In addition, when inserting the workpiece | work W in the mandrel 2, since a pair of clamp board 18 is the structure which raises / lowers with respect to the mandrel 2 by the drive device 21, the space | interval of the mandrel 2 and a pair of clamp board 18 is set. The workpiece W can be made large, and the workpiece W can be easily attached to the mandrel 2.

  Thereafter, the pair of clamp plates 18 is placed on the back bar 3 at the preload position (the position of the gap of the thickness of the workpiece W + α, that is, both ends in the circumferential direction of the workpiece W supported by the mandrel 2 on the pair of clamp plates 18). The position of the workpiece W supported by the mandrel 2 in this state is brought into contact with the side surface of the upper end portion of the center plate 12 (see FIG. 16A).

At this time, since the pair of clamp plates 18 are lowered to the preload position, the distance between the tip of the clamp plate 18 and the back bar 3 of the mandrel 2 is narrowed. As a result, the workpiece W supported by the mandrel 2 is reduced. One end in the circumferential direction is abutted against the side of the upper end of the center plate 12 while being guided by the tip of the clamp plate 18 and the back bar 3.
Further, since the distance between the pair of clamp plates 18 lowered to the preload position is wide, it can be visually observed when one end in the circumferential direction of the workpiece W is abutted against the center plate 12.
Therefore, it becomes very easy to abut one end of the workpiece W in the circumferential direction on the center plate 12.

  When one end in the circumferential direction of the workpiece W is brought into contact with the side surface of the upper end portion of the center plate 12, one clamp plate 18 of the clamp mechanism 6 (a clamp positioned above one end portion of the workpiece W in contact with the center plate 12). The plate 18) is lowered from the preload position to the pressurization position by the drive device 21, and is firmly pressed and fixed by the clamp plate 18 so as not to move the circumferential end of the workpiece W onto the back bar 3 (FIG. 16). (See (b)).

When one clamp plate 18 is lowered from the preload position to the pressurization position, one clamp plate 18 swings upward with a hinge 29 as a fulcrum while compressing the elastic body 19 and the tip of the clamp 18 Moves toward the center plate 12 by the amount of compression of the elastic body 19, and the distance between the pair of clamps 18 becomes narrow.
At this time, a strong frictional resistance acts between the lower surface of the tip of one clamp plate 18 and the upper surface of one end in the circumferential direction of the work W, and moves the one end in the circumferential direction of the work W toward the center plate 12 side. As a result, one end in the circumferential direction of the workpiece W is press-contacted to the center plate 12 and coincides with an ideal weld line (a travel locus of the welding torch 45).

  When one end of the workpiece W in the circumferential direction is pressure-fixed on the back bar 3 by the one clamp plate 18, the supply of compressed air supplied to the drive unit 13 of the center positioning mechanism 4 is stopped. Then, the center plate 12 is lowered by the elastic force of the return compression spring 13c, and the upper end portion of the center plate 12 is housed in the slit-like groove 3b of the back bar 3 (see FIG. 16C).

  When the center plate 12 is lowered, the other end in the circumferential direction of the workpiece W is abutted against one end in the circumferential direction of the workpiece W that is first press-fixed on the back bar 3 by visual observation (see FIG. 16C).

At this time, since the clamp plate 18 located above the other circumferential end of the workpiece W is lowered to the preload position, the distance between the tip of the clamp plate 18 and the back bar 3 of the mandrel 2 is narrowed. As a result, the other end of the workpiece W in the circumferential direction is abutted accurately and reliably without overlapping the circumferential end of the workpiece W while being guided by the tip of the clamp plate 18 and the back bar 3.
Further, when the clamp plate 18 is in the preload position, the elastic force of the elastic body 19 is not applied. Therefore, the interval between the clamp plates 18 is wide, and the both ends of the workpiece W in the circumferential direction are abutted. As a result, the other end in the circumferential direction of the work W is very easily abutted against one end in the circumferential direction of the one-pump W that has been pressure-fixed first.

  When both ends in the circumferential direction of the workpiece W are butted together, the other clamp plate 18 (the clamp plate 18 still in the preload position) of the clamp mechanism 6 is lowered from the preload position to the pressurization position by the drive device 21, and the clamp plate 18 The other end in the circumferential direction of the work W is firmly pressed and fixed so as not to move onto the back bar 3 (see FIG. 16D).

When the other clamp plate 18 is lowered from the preload position to the pressurization position, the other clamp plate 18 swings upward with the hinge 29 as a fulcrum while compressing the elastic body 19, and the tip of the clamp 18 Moves toward the one clamp plate 18 in the pressurizing position by the amount of compression of the elastic body 19, and the interval between the pair of clamps 18 becomes narrower.
At this time, a strong frictional resistance acts between the lower surface of the tip of the other clamp plate 18 and the upper surface of the other end in the circumferential direction of the workpiece W, and presses the other circumferential end of the workpiece W onto the back bar 3. It moves to the one end side in the circumferential direction of the one-piece W that is fixed. As a result, both ends in the circumferential direction of the work W are pressed and adhered, and a butt joint surface without a gap is formed.

Then, when both ends in the circumferential direction of the workpiece W are butt-fixed on the slit-like groove 3b of the back bar 3, argon gas or the like is introduced into the slit-like groove 3b of the back bar 3 from the gas supply port 2e of the mandrel 2. The butt portion of the workpiece W is butt welded by the welding device 7 while supplying the shielding gas.
That is, the welding torch 45 is lowered so that the tip of the tungsten electrode rod 45a faces one end of the butt portion of the workpiece W to generate an arc between the tip of the tungsten electrode rod 45a and the workpiece W. After the stable state is reached, the traveling platform 43 is advanced by the drive device to cause the welding torch 45 to travel along the butt portion of the workpiece W, and the butt portion of the workpiece W is sequentially butt welded.

  At this time, since both ends in the circumferential direction of the workpiece W are brought into close contact with each other in a pressurized state by the clamp plate 18 and the elastic body 19 of the clamp mechanism 6, high-quality and beautiful welding without welding defects such as perforations and dents can be performed. .

When the butt welding of the workpiece W is completed, the supply of the shielding gas to the back bar 3 is stopped, and the welding torch 45 of the welding apparatus 7 returns to the original position. In addition, the clamping state of the workpiece W by the clamping mechanism 6 is released, and the mandrel receiver 11 is rotated from the vertical position to the horizontal position to open the tip of the mandrel 2.
Thereby, the butt welded work W (pipe or drum) can be pulled out from the mandrel 2.

  At this time, since the pair of clamp plates 18 are configured to move up and down with respect to the mandrel 2 by the pair of driving devices 21, the gap between the mandrel 2 and the pair of clamp plates 18 can be increased, and the welded workpiece When removing W (pipe or drum) from the mandrel 2, the workpiece W can be easily removed, and the workpiece W rubs the upper surface of the mandrel 2, the back bar 3, and the lower end surfaces of the left and right clamp plates 18. In other words, it is possible to prevent the mandrel 2, the back bar 3, and the left and right clamp plates 18 from being worn and the workpiece W from being damaged and deformed.

Thus, when the workpiece W bent into a cylindrical shape using the horizontal automatic welding apparatus described above is butt-welded, the workpiece W is butt-matched even when butt welding is performed on a thin plate workpiece W having a narrow clamp width. The state of the part can be confirmed, and the workpiece W can be accurately abutted, and the workpiece W is clamped so that both ends in the circumferential direction of the workpiece W are in close contact when the workpiece W is clamped by the clamp mechanism 6. Therefore, butt welding can be performed without welding defects (perforated, dent, misalignment, overlap, etc.), and high quality pipes and drums can be produced.
Further, this horizontal type automatic hand welding device 7 has a substantially bilaterally symmetric structure, and operation switches 8 for operating the clamp mechanism 6 are provided on both side surfaces of the frame 1, respectively. Since the work can be performed from either position, efficient work can be performed.

  1 is a frame, 2 is a mandrel, 3 is a back bar, 4 is a center positioning mechanism, 6 is a clamp mechanism, 7 is a welding device, 16 is a clamp base, 17 is a clamp movable plate, 17a is an inner clamp movable plate, and 17b is an outside. A clamp movable plate, 18 is a clamp plate, 19 is an elastic body, 21 is a driving device, 26 is an adjustment screw, 29 is a hinge, 31 is a ball screw mechanism, 32 is a servo motor, 33 is a transmission mechanism, and W is a workpiece.

Claims (3)

  A mandrel (2) that is supported in a horizontal posture on the frame (1) and supports a workpiece (W) made of a metal plate bent into a cylindrical shape, and a back bar (3) provided on the upper surface of the mandrel (2); A center positioning mechanism (4) provided on the mandrel (2) for positioning the end surface in the circumferential direction of the work (W), and disposed in a position above the mandrel (2), and in the circumferential direction of the work (W) A horizontal automatic welding apparatus comprising a clamp mechanism (6) for clamping onto the back bar (3) in a state where both end portions of the workpiece are butted and a welding device (7) for butting and welding the butted portion of the workpiece (W) The clamp mechanism (6) includes a pair of clamp bases (16) disposed in an opposing manner in a posture along the mandrel (2) above the mandrel (2), and each clamp base (16). Freely move up and down A pair of clamp movable plates (17) that are held in a posture along the mandrel (2) and are opposed to each other, and swing downward in the posture along the mandrel (2) on the lower surface of each clamp movable plate (17). A pair of clamp plates (18) that are mounted so as to be movable and can be brought into contact with the upper surfaces of both ends in the circumferential direction of the workpiece (W) supported by the mandrel (2), and each clamp movable plate ( 17) and the clamp plates (18), respectively, and the opposed tip portions of the pair of clamp plates (18) are biased downward to hold the pair of clamp plates (18) in an inclined posture. It is provided between the elastic body (19), each clamp base (16) and each clamp movable plate (17), and each clamp movable plate (17) and each clamp plate (18) is moved up and down to each clamp. Pressure of plate (18) Each clamp plate (18) is lowered by the drive device (21), and the tip of each clamp plate (18) is mandrel (2). When the both ends in the circumferential direction of the work (W) are pressed against the upper surfaces of both ends in the circumferential direction of the work (W) supported by the elastic body (19) against the elastic force of the elastic body (19). A horizontal automatic welding apparatus characterized in that it is configured to swing upward and to adjust the distance according to the thickness of the workpiece (W) by reducing the distance between the tip portions of both clamp plates (18).   The pair of clamp movable plates (17) is attached to the inner clamp movable plate (17a) located on the mandrel (2) side, and attached to the outer end of the inner clamp movable plate (17a) so as to be horizontally movable toward the mandrel (2) side. The outer clamp movable plate (17b) is attached to the lower surface of the outer clamp movable plate (17b) via a hinge (29) so that the clamp plate (18) can swing up and down. The adjustment screw (26) for adjusting the gap between the inner clamp movable plate (17a) and the outer clamp movable plate (17b) is inserted into the plate (17b) in a state where it is rotatable and unmovable in the axial direction and adjusted. A screw portion formed at the tip of the screw (26) is screwed to the outer end portion of the inner clamp movable plate (17a) so as to be movable in the axial direction, and the adjustment screw (26) is rotated. Thus, horizontal automatic welding device according to claim 1, characterized in that it has a configuration capable of adjusting the spacing between the ends of the pair of clamping plates which are arranged on opposite form (18).   The pair of motor-driven drive devices (21) is provided between the clamp base (16) and the clamp movable plate (17), and moves the clamp movable plate (17) up and down relative to the clamp base (16). A ball screw mechanism (31), a servo motor (32) disposed on the clamp base (16), a servo motor control unit that servo-controls the servo motor (32), and the rotational movement of the servo motor (32) 31) and a transmission mechanism (33) for transmission to each of them. By controlling the servo motor (32), the lowering position of the clamp plate (18) can be freely set according to the thickness of the workpiece (W). The horizontal automatic welding apparatus according to claim 1, wherein the pressure applied to the clamp plate (18) can be freely adjusted.

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