GB2172232A - Automatic welding apparatus - Google Patents

Abstract

In the apparatus. a jig table (1) is provided thereon with welding machines (15) for applying temporary welding to a workpiece (W) set on the jig table, and additionally conveying means (2) for reciprocating the jig table between a setting station (A) and a welding station (B) is arranged to be movable upwards and downwards by elevating means (16), so that temporary workpiece welding and elevating of the jig table to a predetermined position can be effected while the jig table is advanced from the setting station (A) to the welding station (B). Consequently a time lag from completion of additional welding to the beginning of the next additional welding can be minimised. Elevating is by X-lever mechanisms (34-39). The table base (4) is removable from a tiltable support base (6). A discharge device (17) moves with the jig. At the welding station (18). a plurality of sets of workpiece clamps (12) are selectively movable about a shaft (24) into operative position. <IMAGE>

Description

SPECIFICATION Automatic welding apparatus This invention relates to an automatic welding apparatus which is applied chiefly to a workpiece comprising plural divided parts, and which is so operated that these parts are first applied with a temporary welding to be formed into an integral unit, and this integral unit is then applied with an additional welding to be formed into a workpiece product.

As for an apparatus of this kind, there has been hitherto known such a type one that, as disclosed in Japanese Patent Publication Sho 56-7473, for instance, a jig table for workpiece setting is so provided as to be movable to be reciprocated, by means of a conveying means which extends long in front and rear directions, between a welding station in front and a setting station in rear, and a first welding means for temporary welding and a second welding means for additional welding are so provided at the welding station as to be operable alternatively, so that, after a workpiece set on the jig table is applied with the temporary welding by the first welding means, the jig table is moved upwards so that the workpiece may be transferred to a workpiece holding means provided at an upper portion of the welding station, and after the transfer of the workpiece, the jig table is moved back to the setting station, and at during the time the workpiece held by the holding means is applied with the additional welding by the second welding means, and during the additional welding operation, a setting operation of the next workpiece on the jig table may be carried out at the setting station.

This type one, however, is inconvenient in that the next additional welding on the next workpiece cannot be carried out unless such procedural steps are complete that, after the completion of the additional welding, the jig table is moved to advance to be introduced into the welding station, and thereafter the temporary welding is made on the earlier workpiece and the transfer thereof to the holding means by elevating of the jig table are carried out. Therefore, it is desirable to decrease this time lag for improvement in the productivity of completely welded workpieces.

This invention provides an automatic welding apparatus in which a jig table for workpiece setting is so provided as to be movable to be reciprocated by means of a conveying means which extends long in front and rear directions between a welding station in front and a setting station in rear, and there is provided at an upper portion of the welding station a workpiece holding means and an additional welding means for applying an additional welding to the workpiece held by the holding means so that after the workpiece set on the jig table is applied with a temporary welding, the workpiece is transferred to the holding means by an elevating movement of the jig table, and after the transfer of the workpiece, the jig table is moved back to the setting station from the welding station; there being provided, on the jig table, welding machines so that during the advance movement of the jig table, the workpiece set on the jig table may be applied with a temporary welding by the welding machines, and additionally there is provided an elevating means for elevating and lowering the conveying means so that during the reciprocating movement of the jig table, the conveying means may be moved upwards and downwards.

One embodying example of this invention will be explained with reference to the accompanying drawings, in which:~ Figure 1 is a side view of one example of this invention apparatus, Figure 2 is a front view, viewed from the left side in Fig. 1, of the same under the condition that an conveying means thereof is at an elevated position, with a jig body thereof being omitted from a viewpoint of simplification, Figure 3 is a front view of an unloading means thereof, Figure 4 is a front view of a cam plate which is to be provided at a setting station thereof, Figure 5 is a side view of a jig table, and Figure 6 is a sectional view taken along the line VI-VI in Fig. 5.

Referring to Figs. 1 and 2, numeral 1 denotes a jig table for workpiece setting, and numeral 2 denotes a conveying means for reciprocating the jig table 1 between a welding station B in front and a setting station A in rear. The jig table 1 is so constructed that a jig body 4 having plural setting members 3 such as positioning pins, clamp members or the like for positioning and fixing plural divided parts constituting a workpiece W is detachably and replaceably attached, through a replacement mechanism arranged to be operated by attaching and detaching cylinders 7 as explained in detail hereinafter, to a jig base 6 supported on a carrier 5.The conveying means 2 is so constructed that there are provided a pair of right and left side plates 8, 8 extending long in front and rear directions between the two stations A, B, and each of the side plates 8, 8 is provided on its inside surface with a guide rail 9 and a conveying chain 10 extending along the lengthwise direction thereof. The carrier 5 is provided between the two side plates 8, 8 and is supported movably through plural guide rollers 5a on a guide rail 9 on each side and is connected through a connecting member 5b to a chain 10 on each side so that, by a reciprocating circulation driving of each chain 10, the carrier 5, accordingly, the jig table 1 may be given a reciprocating movement between the setting station A and the welding station B.Additionally, in the illustrated example, the jig base 6 is tiltably supported on the carrier 5, and each cam plate 11 having a cam groove 1 1a which is inclined downwards rearwardly and continued to each guide rail 9 is so provided tiltably, as shown clearly in Fig. 4, at the setting station A as to be positioned inside the rear end portion of each side plate 8 so that if the jig table 1 is returned to the setting station A under such a condition that each cam plate 11 is raised upright, each of protruded guide rollers 6a, 6a provided on both sides of the rear end portion of the jig base 6 may be inserted into each cam groove 1 lea, and thereby the jig base 6 may be tilted rearwards and downwards about its pivot portion 6b, and as a result a workpiece setting work to the jig body 4 at the setting station A can be carried out easily by a worker in his easy comfortable posture.

At the time of replacement of the jig body 4 explained hereinafter, the jig table 1 is returned to the setting station A from the welding station B in such a state that each cam plate 11 is brought to be laid down so that a pin 5d arranged to be moved with a lock cylinder 5c provided on the carrier 5 is brought into engagement with the jig base 6 as shown in Fig. 6 for keeping the jig base 6 in its horizontal posture and carrying out the replacement thereof. Numeral 11 b denotes a cylinder for rising and lowering the cam plate 11.

Each conveying chain 10 is extended between a driving sprocket 10a and plural idle sprockets 10b provided on each side plate 8 so as to be driven to circulate in either direction of forward and backward directions, and a pair of the driving sprockets 10a, 10a provided on the two side plates 8, 8 are interconnected through a synchronizing shaft 10c so that the two sprockets 10a, 10a may be synchronously driven by a driving motor 10d provided on one of the two side plates 8, 8.

At the foregoing welding station B, there is disposed a workpiece holding means 12 on an upper side thereof and two additional welding means 13 on both sides thereof. The holding means 12 is provided with plural clamp members 12a for clamping the workpiece W, and these clamp members 12a are so provided on an upper portion of a machine frame 14 built upright at the welding station B as to be extended downwards. Each additional welding means 13 comprises an industrial robot having welding machines 13a so that the workpiece W held by the holding means 12 may be applied with a predetermined additional welding by the machines 13a.

According to this invention, the jig table 1 is provided with welding machines 15 loaded thereon so that, during the time that the jig table 1 is being advanced to the welding station B, the workpiece W on the jig table 1 may be applied with a temporary welding by the welding machines 15. In addition there is provided an elevating means 16 for elevating and lowering the conveying means 2 so that, while the jig table 1 is being reciprocated between the two stations A, B, the-jig 1 may be moved upwards and downwards.

This will be explained more in detail with reference to the illustrated example as follows: A plurality of the welding machines 15 is provided on the jig body 4 of the jig table 1 at positions corresponding to respective temporary fixing positions of the pural divided parts constituting the workpiece W, and the elevating means 16 is composed of a pair of X-shaped link mechanisms which are so disposed as to be connected to the respective side plates 8, 8 on both sides of the conveying means 2.

In the illustrated example, there is provided a delivery means 17 for delivering the workpiece W applied with the additional welding at the welding station B from the jig table to a discharging station C in front thereof. As shown in Fig. 3, the means 17 comprises a carrier 17a supported on guide rails 18, 18 extending between the two stations B, C, and a receiving member 1 7c for the workpiece W is so provided on the carrier 17a through a cylinder 17b as to be movable upwards and downwards, and the carrier 17a is connected through a connecting rod 17d to the foregoing jig table 1 so that the carrier 17a may be given a reciprocating movement between the discharging station C and the welding station B, by the reciprocating movement of the jig table 1 between the welding station B and the setting station A.

Next the operation of the foregoing apparatus will be explained as follows: First, the plural divided parts constituting the workpiece W are set on the jig table 1 located in the setting station A. Thereafter, the conveying means 2 and the elevating means 16 are operated synchronously, and thereby the jig table 1 is moved to advance to the welding station B while being moved upwards, and at the same time, that is, during moving of the jig table 1, the workpiece W is being applied with a temporary welding by the welding machines 15 on the jig table 1.

By this operation, at the time point of completion of the advance movement of the jig table 1, the jig table 1 reaches a predetermined workpiece transfer position which meets the workpiece holding means 12 provided on the upper portion of the welding station B, and at the same time the temporary welding of the workpiece W is completed, and thus there can be removed a time lag made until either a temporary welding or an upward movement of the jig table 1 to the workpiece transfer position from the completion of the advance movement of the jig table 1, and the transfer of the workpiece W to the holding means 12 from the jig table 1 can be carried out at a high efficiency.

After the completion of the transfer of the workpiece, the jig table 1 is returned to the setting station A by an operation which is reverse to the above, and at the same time the workpiece W held by the holding member 12 is applied with an additional welding by the additional welding means 13, and in addition during this welding operation the next workpiece W is set on the jig table 1 already returned to the setting station A.

On this occasion, the carrier 17a of the delivery means 17 is moved in conjunction with returning means of the jig table 1 so as to be introduced into the welding station B for waiting for completion of the additional welding, and the receiving member 1 7c of the discharging means 17 is moved upwards and downwards for receiving a product of the completely welded workpiece W thereon from the holding member 12.

After the receiving of the workpiece product W, the jig table 1 is again advanced to the welding station B in almost the same manner as above, and the carrier 17a is delivered to the discharging station C for unloading the workpiece product W therefrom, and at the same time the next workpiece W on the jig table 1 already subjected to the temporary welding is transferred to the holding member 12. Thus, by repeating the foregoing operations, welding operations of the workpieces W can be carried out in succession one after another.

Depending on a certain kind or model of the workpiece W, it often happens that the temporary welding thereof is not completed during the advance movement of the jig table 1.

In that case, after the completion of the advance movement of the jig table 1, the subsequent temporary welding of the unwelded portions thereof are carried out by the additional welding means 13 and thereafter the workpiece W is transferred to the workpiece holding means 12. Even by this way, a time lag can be extremely shortened, in comparison with the conventional apparatus wherein the temporary welding begins after the completion of the advance movement of the jig table.

The above has been explained about the fundamental construction of this invention apparatus and the operation thereof. However, in order to correspond to a change of the kind or model of the workpiece W to be welded, the jig body 4 of the jig table 1 and the workpiece holding member 12 are desired to be replaceable with respective predetermined ones. For this purpose, it can be considered that a replacement operation is carried out by using a lifting means such as a crane or the like, but this is low in working efficiency.

Accordingly, in the illustrated example, respective replacement mechanisms for carrying put a replacement operation of the jig body 4 and the workpiece holding member 12 at a high efficiency are constructed as follows.

First, the replacement mechanism for the jig body 4 is explained as follows: As shown in Figs. 5 and 6, the jig base 6 is provided thereon with an elevating frame 19 which is movable upwards and downwords in relation to the jig body 4, and additionally there is provided a clamp member 20 which is so arranged that, by lowering of the elevating frame 19, the same is brought into engagement with the jig body 4 to press the engaging body 4 for fixing it to the jig base 6, and a guide member 21 which is so arranged that, by elevating of the elevating frame 19, the same is brought into abutment with the jig body 4 for so supporting the jig body 4 for so supporting the jig body 4 as to be movable laterally.

More in detail, a pair of front and rear Lshaped grooves 4b, 4b extending laterally are made in the lower surface portion of the jig body 4 so that there remain therein respective lower side tab portions 4a, 4a, and a pair of the elevating frames 19 are disposed in front and rear relationship and extend long in the lateral direction along the foregoing grooves 4b, 4b, and also each of the elevating frames 19, 19 is arranged to be movable upwards and downwards by a pair of right and left cylinders 7, 7 attached to the jig base 6.

Additionally, each elevating frame 19 is provided thereon with plural pins 19a arranged to be inserted in each groove 4b, and the foregoing clamp members 20 each comprising a plate-shaped member which is long laterally and faces an upper surface of the tab portion 4a is attached to top portions of these pins 19a, and additionally, a plurality of first guide rollers 21a cooperating with the foregoing guide member 21 are pivotally supported thereon so as to face a lower surface of the tab portion 4a, and each of second guide rollers 21b which are arranged to be in abutment with the inner end edge of the tab portion 4a is pivotally supported on each pin 19a so that the jig body 4 may be so supported as to be movable laterally by the first guide rollers 21a under the condition that shake movements thereof in the front and rear directions are prevented by the second rollers 21b.

In addition, the jig body 4 is so arranged as to be supported on receiving seats 6d on the jig base 6, and be set in position by such positioning pins 6c on the jig base 6 that are arranged to be mounted in positioning openings 4c made in the lower surface thereof.

Referring to the drawings, numeral 4d denotes a hook provided on a lateral side surface of the jig body 4, numeral 22 denotes a transformer for the welding machines 15 mounted on the jig base 6, and numeral 23 denotes a receiving base for jig replacement.

Next, the operation of the foregoing replacement mechanism will be explained as follows: In an ordinary case, the elevating frame 19 is applied with a pressure moving it downwards by a downward movement of the attaching and detaching cylinders 7, whereby the clamp member 20 is brought into engagement with the tab portion 4a for pushing the jig body 4 downwards, and consequently the jig body 4 is fixed under the pressure thereof to the jig base 6 while the same is set in position by the positioning pins 6c.

When the jig body 4 is to be replaced with another one in compliance with a change of the kind of the workpiece W, the elevating frame 19 is elevated by the attaching and detaching cylinders 7. By this operation, the pressed fixing of the jig body 4 to the tab portions 4a by the clamp 20 is released, and at the same time the guide member 21 on the elevating frame 19 is brought into abutment with the lower surface of the tab portion 4a for supporting the same, and the jig body 4 is lifted upwards to leave the jig base 6 under the condition that the same is supported on the guide member 21. If the jig body 4 is elevated to a position at which the same is apart from the positioning pins 6c, the same becomes movable laterally.Thus, by putting a proper metallic member on the hook 4d of the lateral side surface thereof, the jig body 4 can be pulled out simply onto the receiving base 23 on the lateral side thereof. Thereafter, another jig body 4 is introduced into a position on the guide member 21 through the receiving base 23, and the elevating frame 19 is lowered in almost the same manner as above so that the jig body 4 may be fixed under the pressure thereof to the jig base 6 by the clamp member 20.

Next, the replacement mechanism for the workpiece holding means 12 will be explained as follows: As shown in Figs. 1 and 2, a rotary shaft 24 is provided horizontally on an upper portion of the foregoing machine frame 14, and a plurality of the workpiece holding means 12, for instance, three units, is provided therearound through a supporting member 25, and the rotary shaft 24 is arranged to be rotatable by means of an index means 26.The index means 26 comprises such a rotation driving mechanism that the rotary shaft 24 is arranged to be rotated by such a manner that a rack 28 provided on the machine frame 14 and meshed with a pinion 27 on the shaft 24 is moved forwards and backwards by a cylinder 29, and such a positioning means that the rotary shaft 24 is arranged to be set in position by such a manner that a stopper 31 provided on the machine frame 14 and directed forward an index plate 30 fixed on the rotary shaft 24 and having index grooves 30a made at circumferential three positions is movable to be brought into engagement and disengagement with any of the index grooves 30a by a cylinder 32.By the cooperation of the two mechanisms, the rotary shaft 24 is given a turning of a proper predetermined angle, and consequently any desired one of the three workpiece holding means 12 is selected to be positioned at an operative position below the rotary shaft 24. Thus, a replacement of the workpiece holding means 12 at the time of change of the kind of the workpiece W can be carried out at a high efficiency.

The foregoing elevating means 16 comprises a pair of X-shaped link mechanisms disposed on both sides. The X-shaped link mechanism on each side is so constructed that a pair of links 33, 34 are crossed one another in the form of X and are pivotally interconnected at a crossing point 35 of the middle portions thereof, and, in addition, these links 33, 34 are pivotally attached at their upper ends to the side plate 8 on the side surface of the conveying means 2, and at their lower ends to a stationary frame 36 provided on the lower side thereof, and an upper end pivot portion 33a of the first link 33, which is one of the two links 33, 34, is arranged to be slidable horizontally along a guide portion 37 provided on the side plate 8, and a lower end pivot portion 34a of the second link 34, which is the other of the two links 33, 34, is arranged to be moved along a guide portion 39 made in the stationary frame 36 by means of a driving source 38 so that the side plate 8 may be moved upwards and downwards.

Numeral 33b denotes a lower end pivot portion of the first link 33, numeral 34b denotes an upper end pivot portion of the second link 34.

The guide portion 37 provided on the side plate 8 is so constructed that, as shown in Figs. 1 and 2, a movable frame 37b is movable horizontally along upper and lower guide rails 37a, 37a provided on the side plate 8, and an upper end of the first link 33 is pivotally attached to the movable frame 37b. The guide portion 39 provided on the stationary frame 36 is in the form of a long groove, and the lower end pivot portion 34a of the second link 34 is in slidable engagement therewith through a movable member 39a mounted on the same shaft, and a piston rod 38a extending from a cylinder constituting a driving source 38 is connected to the pivot portion 34a.

Thus, according to this invention, the jig table is provided thereon with the welding machines for applying the temporary welding to the workpiece set on the jig table, and additionally the conveying means for reciprocating the jig table between the setting station and the welding station is arranged to be movable upwards and downwards by the elevating means, so that the temporary welding and the elevating of the jig table to the pre determined position can be given while the jig table is moved to advance to the welding station, and consequently a time lag from the completion of the additional welding to the beginning of the next additional welding can be extremely shortened to result in improvement in the productivity, as compared with that in the case of the conventional example wherein the temporary welding of the workpiece and the elevating of the jig table are carried out after the completion of the advance movement of the jig table.

Claims (6)

1. An automatic welding apparatus in which a jig table for workpiece setting is so provided as to be movable to be reciprocated by means of a conveying means which extends long in front and rear directions between a welding station in front and a setting station in rear, and there is provided at an upper portion of the welding station a workpiece holding means and an additional welding means for applying an additional welding to the workpiece held by the holding means so that after the workpiece set on the jig table is applied with a temporary welding, the workpiece is transferred to the holding means by an elevating movement of the jig table, and after the transfer of the workpiece, the jig table is moved back to the setting station from the welding station;; there being provided, on the jig table, welding machines so that, during the advance movement of the jig table, the workpiece set on the jig table may be applied with a temporary welding by the welding machines, and additionally there is provided an elevating means for elevating and lowering the conveying means so that, during the reciprocating movement of the jig table, the conveying means may be moved upwards and downwards.

2. An automatic welding apparatus as claimed in claim 1, wherein the jig table comprises a carrier which is movable to be reciprocated by the conveying means, a jig base provided on the carrier, and a jig body provided detachably on the jig base, and the jig base is provided thereon with an elevating frame which is movable upwards and downwards in relation to the jig body, and the elevating frame is provided with a clamp member which is so arranged that, by lowering of the elevating frame, the clamp member may be brought into engagement with the jig body under pressure for fixedly pressing the jig body against the jig base, and a guide member which is so arranged that, by elevating of the elevating frame, the clamp member may be brought into abutment with the jig body for so supporting the jig body as to be movably laterally.

3. An automatic welding apparatus as claimed in claim 2, wherein the jig base is tiltably supported on the carrier, and a cam plate having a cam groove which is inclined downwards rearwardly and is arranged to be brought into engagement with a protrusion provided on a rear portion of a side surface of the jig base is so provided at the setting station as to be tiltable to be raised and be laid down so that, when the cam plate is in its raised position, the jig base may be inclined downwards and rearwards at the setting station, and additionally the carrier is provided with a lock member which is so arranged that, when the cam plate is in its laid down position, the same may be operated to hold the jig base in its horizontal posture.

4. An automatic welding apparatus as claimed in claim 1, 2 or 3, wherein a rotary shaft is horizontally provided above a machine frame built at the welding station, and a plurality of the workpiece holding means is attached around the rotary shaft so that, by turning the rotary shaft by means of an index means connected thereto, any desired one of the workpiece holding means may be selected to be brought to an operative position on a lower side of the rotary shaft, and thus the workpiece supported on the jig table may be transferred to the workpiece holding means selected at the operative position.

5. An automatic welding apparatus as claimed in claim 1, 2, 3 or 4, wherein the elevating means comprises a pair of X-shaped link mechanisms, and each mechanism comprises a pair of links which are crossed one with another and are interconnected pivotally at a crossing point of the middle portions thereof, and the two links are pivotally attached at their upper ends to the conveying means and at their lower ends to a stationary frame provided on a lower side thereof, and an upper end pivot portion of a first link, which is one of the two links, is movable horizontally along a guide portion provided on the conveying means, and a lower end pivot portion of a second link, which is the other of the two links, is movable along a guide portion provided on the stationary frame by a driving source for elevating and lowering the conveying means.

6. An automatic welding apparatus substantially as hereinbefore described with reference to the accompanying drawings.