Cap mounting system

Abstract

Cap mounting system for the electrode caps (9) of, in particular, robot-controlled welding guns (6), comprising a cap holder (1) positioning the caps in the correct orientation for transfer to the electrode shafts (6.1, 6.2) of the welding gun and a cap feeder (2) loading the cap holder, including a cap supply magazine, characterized in that the cap feeder includes at least one conveying channel (feed hose 4) extending from a refill opening (7) outside the working area of ​​the welding gun towards the cap holder (1), which is closed in cross-section and through which compressed air flows for transporting the cap supply to the cap holder.

Description

[0001] The invention relates to an automatic cap assembly system for the electrode caps of, in particular, robot-controlled welding guns, comprising a cap holder which positions the caps in the correct orientation for transfer to the electrode shafts of the welding gun and a cap feeder which loads the cap holder, including a cap storage magazine, according to the preamble of claim 1 or 6.

[0002] Automatic cap assembly systems for welding robots are known in numerous embodiments, e.g., from DE 35 15 597 A1, DE 10 2007 041 505 B3, DE 10 2010 019 520 A1, DE 297 10 142 U1, DE 299 05 872 U1, DE 20 2007 017 935 U1, or US 5 073 692 A. With such assembly systems, the cap magazine must be manually refilled or replaced from time to time, and for this purpose, not only the assembly system itself but also, for safety reasons, the welding robot must be shut down for the duration of the refilling process, resulting in a production downtime that increases proportionally to the number of welding robots in use.In addition, the known cap mounting systems for the two electrode caps, which are attached to the welding gun shafts in pairs, each require separate feeders and separate cap magazines, for example in the form of drum magazines that can be filled from both sides (DE 35 15 597 A1, DE 10 2007 041 505 B3, DE 297 10 142 U1 and DE 299 05 872 U1) and / or only one electrode cap can initially be attached to one electrode shaft of the welding gun, and this must first be rotated 180° by the robot before the other electrode shaft can be fitted with the second electrode cap, which, due to the often confined space and the correspondingly limited maneuverability in the robot's working area, is only possible, if at all, with increased control effort and time for cap mounting (DE 10 2010 019 520 A1 and DE 20 2007 017 935 U1).

[0003] The object of the invention is to create a cap mounting system of the type mentioned above, which has a significantly improved design and function.

[0004] This problem is solved according to the invention by the cap mounting system characterized in claim 1 or 6.

[0005] According to the first embodiment of the invention as claimed 1, the cap magazine, due to its special design as a closed cross-section, compressed air-fed conveyor belt for cap transport with a refilling opening outside the working area of ​​the welding gun, can not only be easily refilled without interrupting the ongoing welding process, thereby saving valuable production time, but at the same time the storage capacity is also significantly increased due to the resulting increase in the length of the conveyor belt and can be practically arbitrarily enlarged by extending the conveyor belt beyond the absolutely necessary extent, so that the cap magazine only needs to be refilled at desired long intervals in a labor-saving manner, whereby the compressed air conveying of the cap supply ensures trouble-free, structurally uncomplicated and gravity-independent cap transport even over longer distances.

[0006] In a particularly preferred manner, the inner diameter of the conveyor track is slightly larger than the outer diameter of the electrode caps, so that an airflow is created in the annular gap between the conveyor track and the electrode caps, which captures all individual caps of the cap supply in the conveying direction and thereby guarantees an extremely gentle, largely shock-free cap transport.

[0007] Preferably, the conveyor is designed as a flexible supply hose, which, preferably, is bent at least in places and selectively supplied with compressed air in such a way that, at the curved section of the supply hose, one or a few electrode caps are detached from the front end of the cap string, pass through the curved section and then, depending on the spatial orientation of this section, reach the charging area of ​​the cap holder in the remaining part of the conveyor path under the influence of gravity and / or compressed air, whereupon the compressed air flow in the supply hose is interrupted until the next charging cycle.

[0008] Optionally, but preferably additionally, the cap holder according to the second embodiment of the invention as per claim 6 is rotatably driven and provided with at least one holding position open outwards in the radial direction of the axis of rotation. This holding position is loaded with a single cap from a pair of caps, which are aligned coaxially with the electrode shafts by the holder during transfer to the welding gun, via a single feed channel controlled sequentially by corresponding rotational positioning of the holder. This results in a significant structural simplification of the assembly system because, instead of a double feed, only a single cap feed with a single supply magazine is required, and yet the pair of caps can be picked up from the electrode shafts without complex control and, in particular, rotational movements of the welding gun.

[0009] Preferably, the holder contains several cap holding positions, each pair open diametrically to the outside of the axis of rotation, so that both electrode shafts of the welding gun can be fitted with a pair of caps without having to reload the holder in between.

[0010] Although the rotational position of the holder on the cap feeder, as well as the pairwise diametrical positioning of the electrode caps on the axis of rotation by the holder, is fixed, in a particularly preferred embodiment of the invention the rotational position of the holder during the cap transfer to the welding gun is not limited to a specific angle of rotation relative to the cap feeder, but is variably adjustable in accordance with the most favorable rotational position of the welding gun depending on the available space conditions for the cap assembly.

[0011] In a further preferred embodiment of the invention, the holding position(s) are equipped with a cap fixing that is released during loading to prevent unintentional cap loss, and the loading process is also expediently carried out for safety reasons by means of a stroke-moving driven sliding mechanism that transfers the caps to the holding position via a lateral insertion opening, which, in conjunction with the single channel provided according to the invention for cap feeding, contains only a single loading element instead of a conventionally double one, resulting in further structural simplification.

[0012] The invention will now be explained in more detail with reference to several exemplary embodiments in conjunction with the drawings. These show, in a highly schematic representation: Fig. 1a, b the view of a cap assembly system according to the invention with a double cap feeder and a stationary cap holder (a) as well as an enlarged partial view in the transfer area of ​​the cap feeder (b); Fig. 2 a cap mounting system according to the invention with a single cap feeder and a rotatably positionable holder; and Fig. 3 another embodiment of the invention with a greatly simplified cap loading of a rotatable holder provided with a single holding position.

[0013] The in Fig. The automatic cap assembly system shown in 1a, b comprises as its main components a stationary cap holder 1 and a cap feeder designated 2, which is provided in duplicate with a feed channel 3.1 and 3.2 each, and a cap magazine 4.1 and 4.2 in the form of a flexible feed hose, which is dimensioned to be long enough to run from the feed channel 3.1 or 3.2 via several curved sections 5, such as the siphon-like curved section 5.1 in the upper feed hose 4.1, beyond the dashed-line indicated working area of ​​a robot-guided welding gun 6 to a refilling point 7 located away from the working area.

[0014] The cap holder 1 contains two coaxially arranged, pocket-shaped cap holding positions 8.1 and 8.2, each of which is loaded with a single electrode cap 9 with an outwardly directed receiving opening 10 in a position suitable for transfer to the welding gun 6, such that the electrode cap 9 is inserted from the feed channel 3 via a lateral insertion opening 13 by a loading element 12.1 or 12.2 which is driven by an actuator 11 in a stroke-moving manner ( Fig. 1b) of the holder 1 is transferred to the respective holding position 8, whereby the electrode cap 9 is fixed in the holding position 8 by a securing device, which consists, for example, of a leaf spring 14 adapted to the cap shape and spring-loaded ball locks 15.

[0015] With the holder 1 loaded, the welding gun 6 is moved coaxially to the pair of caps 9.1 and 9.2 located in the holder 1, aligning the electrode shafts 6.1, 6.2, and by closing and opening the welding gun 6, the electrode shafts 6.1 and 6.2 are each fitted with an electrode cap 9, without the welding gun 6 having to be rotated in between.

[0016] To refill the supply hoses 4.1 and 4.2, a ball valve 16 located at the refilling point 7 is opened, and the supply hose 4.1 or 4.2 is filled with electrode caps 9, after which the ball valve 16 is closed again. Subsequently, the supply hoses 4, whose inner diameter is slightly larger than the outer diameter of the electrode caps 9, are pressurized with compressed air via a valve control 17, so that an airflow is created in the annular gap between the supply hose 4 and the electrode caps 9 along the entire length of the cap assembly, which propels the caps 9 towards the supply channel 3. The arc pieces 5 act like a cap lock, in which individual electrode caps 9 detach from the front end of the cap string, pass through the arc piece 5 and in the last part of the conveying path under the influence of gravity (at the upper feed hose 4.1) or under the influence of compressed air (at the lower feed hose 4.1).2) enter the respective feed channel 3 and are inserted into the holding positions 8 by actuating the actuators 11, whereupon the compressed air supply to the feed hoses 4 is switched off until the cap pair 9.1, 9.2 has been transferred to the welding gun 6 and a new loading cycle begins.

[0017] The control unit 18 required for the automatic workflow is not shown in detail, but only the level sensors 19, which trigger a warning signal when the cap supply in the supply hose 4 needs to be refilled.

[0018] The in Fig. The cap mounting system shown in Figure 2, where the components corresponding to the first embodiment are identified by the same reference numeral, differs from it primarily in that the stationary holder 1 is replaced by a rotatably driven holder 1 and, instead of a double cap feeder, only a single cap feeder 2 with a single feed channel 3 including a singular, actuator-operated loading element 12 and only a single feed hose 4 forming the cap magazine is required.

[0019] The holder 1 has several holding positions 8.1 and 8.2, arranged in pairs and, in this case, radially open outwards diametrically to the axis of rotation A of the holder 1. These holding positions are sequentially positioned on the feed channel 3 by actuating the rotary drive 20 and each is loaded with a single cap 9. In this embodiment, the welding gun 6 can assume any desired rotational position during the transfer of the caps 9, depending on the available space. The cap-loaded holding positions 8.1 and 8.2 are aligned to this position by the rotary drive 20 rotating the holder 1 accordingly. The pair of caps 9.1 and 9.2 is then placed onto the electrode shafts 6.1 and 6.2 by opening and closing the holder 1, but without changing the angular position of the welding gun 6, and removed from the holding positions 8.1 and 8.2.With the assembly system designed in this way, the construction in the area of ​​the cap feed 2 is greatly simplified and a variable rotational position of the welding gun 6 with respect to the transfer position is enabled; otherwise, however, this embodiment, in particular with regard to the design of the cap magazine as a selectively compressed air-fed supply hose 4 with a refilling opening outside the working area of ​​the welding gun 6, is structurally and functionally identical to the assembly system according to . Fig. 1.

[0020] In Fig. Figure 3 shows another cap mounting system according to the invention, which is greatly simplified in the area of ​​the feed channel 3 and shows that even a single holding position 8 is sufficient for mounting the caps (in Fig.3 welding tongs (not shown) are sufficient. In this embodiment, the lateral insertion opening of the holding position 8 is omitted; it is therefore only open on the cylindrical outer surface of the rotary holder 1, and the feed channel 3 runs radially to the axis of rotation A adjacent to the outer surface of the rotary holder, so that the electrode caps 9, after passing through the curved section 5.1 of the feed hose 4, enter the holding position 8 directly under the influence of gravity and / or compressed air, without the need for an actuator-driven loading mechanism.

[0021] For cap fixation, a spring-loaded swivel arm 21 with a pressure piece 22 is arranged at the holding position 8, by which the electrode cap 9 is clamped in the holding position 8 in the rest position of the swivel arm 21 (not shown). If, however, the holder 1 is rotated into the loading position shown, the swivel arm 21 is pivoted against the spring force on an inclined control ramp 23 of the feed channel 3 into the release position shown, so that the holding position 8 can be loaded without hindrance.

[0022] To transfer the electrode caps to the welding gun, the holder 1 is rotated relative to the loading position until the holding position 8, with the electrode cap 9 located therein, is aligned coaxially with the electrode shafts of the welding gun. Then, only one electrode shaft is initially loaded. The holder 1 is then rotated back to the loading position, loaded with the second electrode cap 9 of the pair, and subsequently rotated further to an angular position offset by 180° relative to the first transfer position. Here, the other electrode shaft of the welding gun is now loaded with the second electrode cap 9. Otherwise, the construction and operation are the same as in the previously described embodiments.

Claims

[1] Cap mounting system for the electrode caps (9) of, in particular, robot-controlled welding guns (6), comprising a cap holder (1) which positions the caps in the correct position for transfer to the electrode shafts (6.1, 6.2) of the welding gun and a cap feeder (2) which loads the cap holder including a cap storage magazine, characterized by , that the cap feeder includes at least one conveying channel (feed hose 4) extending from a refilling opening (7) outside the working area of ​​the welding gun towards the cap holder (1), closed in cross-section and through which compressed air flows for the transport of the cap supply to the cap holder. [2] Cap mounting system according to claim 1, characterized by that the inner diameter of the conveyor track (4) is slightly larger than the outer diameter of the electrode caps (9). [3] Cap mounting system according to claim 1 or 2, characterized bythat the conveyor track (4) is curved at least in places and is selectively supplied with compressed air to regulate the cap supply to the cap holder (1). [4] Cap mounting system according to claim 3, characterized by that the conveyor includes a flexible feed hose (4) with an end section arranged on the side of the cap holder (1) and a cap gate in the form of an arc piece (5.1) arranged on the inlet side of the end section, blocking the cap supply to the end section in the absence of compressed air. [5] Cap mounting system according to one of the preceding claims, characterized by that the electrode caps (9) in the final section of the conveyor track (4) can be moved towards the cap holder (1) under the influence of gravity. [6] Cap mounting system for the electrode caps (9) of, in particular, robot-controlled welding guns (6), comprising a cap holder (1) positioning the caps in pairs in a position appropriate for transfer to the electrode shafts (6.1, 6.2) of the welding gun coaxially to each other with cap openings accessible from the outside, and a cap feeder (2) loading the cap holder including a cap storage magazine, characterized by , that the cap holder (1) is rotatably positionable and is provided with at least one cap holding place (8) open outwards in the radial direction of the axis of rotation (A) and can be loaded successively with the corresponding individual caps (9.1, 9.2) of a pair of caps at a single feed channel (3) controlled by rotating the holder ( Fig. 2). [7] Cap mounting system according to claim 6, characterized by that the holder (1) is provided with several cap holding positions (8.1, 8.2) arranged diametrically to the axis of rotation (A). [8] Cap mounting system according to claim 6 or 7, characterized by that the transfer position of the holder (1) to the welding gun (6) is variably adjustable. [9] Cap mounting system according to one of the preceding claims, characterized by a fixing (14, 15; 21, 22) securing the caps (9) to the holder (1), which is released when the holder is loaded. [10] Cap mounting system according to one of the preceding claims, characterized by that the feeder (2) contains at least one lifting element (12) which is driven by a stroke and transfers a single cap (9) taken from the supply magazine to the holder (1).

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