(12) United States Patent
`Kaeseler
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 8,314,356 B2
`Nov. 20, 2012
`
`US008314356B2
`
`(54) SPOT WELDING CAP CHANGER
`
`5
`3/1996 Saito
`,495,663 A *
`5,530,218 A *
`6/1996 Nakamuraetal. ..
`3/1998 Voilmyetal.
`5,734,141 A *
`7,353,578 B2* 4/2008 Nakajima et a1.
`
`29/762
`.. 219/8625
`219/8625
`29/239
`
`FOREIGN PATENT DOCUMENTS
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`
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` 30021 4495 2232 420% 2260 127/ 002%
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`1112 CAAA
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`11
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` 2384 0090 0090 2212
`1194
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`(76) Inventor: Werner Kaeseler,Baunatal (DE)
`*
`Notice:
`Sub'ect to an disclaimer, the term of this
`J
`y
`patent is extended or adjusted under 35
`S w 5 2 1
`S. U
`m1 2
`w M b M 0
`C 1 .J
`4 9 1 5 9 . 1 / l
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`EERO DDFW
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`)) l 2 2 2 ((
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`l mm A P
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`.n 1m 0 e N H
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`. F
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`(86) PCT No.:
`§ 371 (0X1)’
`(2), (4) Date:
`
`PCT/EP2006/064417
`
`Jul. 30, 2008
`
`(87) PCT Pub. No.: WO2007/012593
`
`PCT Pub. Date: Feb. 1, 2007
`
`(65)
`
`(30)
`
`Prior Publication Data
`
`US 2009/0101628 A1
`
`APT- 23> 2009
`
`Foreign Application Priority Data
`
`(DE)
`
`10 2005 035 915
`
`Jul 28 2005
`'
`’
`(51) Int, Cl,
`323K 9/26
`(52) US. Cl.
`219/861; 219/868
`(58) Field of Classi?cation Search
`None
`See application ?le for complete search history.
`
`(200601)
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`
`
`4,794,221 A * 12/1988 Takabeetal. 5,073,692 A * 12/1991 Jackson et al
`
`219/86.8
`.. 219/868
`
`
`
`
`
`
`
`11 0
`2
`* cited by examiner
`
`Primary Examiner * Kiley Stoner
`(74) Attorney, Agent, or FirmiBrowdy and Neimark,
`PLLC
`
`ABSTRACT
`
`(57)
`The invention relates to a spot Welding cap changer (1) With a
`cap puller (2) and tWo cap magazines (3, 3A), the cap puller
`(2) having a gripper (20) With spring-loaded, pivotable jaWs
`(21, 22), Which in response to a turning and axial pulling-off
`movement detaches a spot Welding cap (K) ofa pincer spot
`Welding head introduced into it from a shaft of the pincer
`Welding head in such a Way that it is clamped to prevent it
`twisting, andthe Cap 11128211111656, 3A)hO1diI1g SPOt Welding
`caps respectively in a round cap carrier (31) such that they are
`circularly arranged in a directed and oriented manner and are
`respectively transported individually one after the other into
`an access position against a stop (32) by an advancing force
`(P)
`
`16 Claims, 5 Drawing Sheets
`
`Ex. C&D 1005, page 1
`
`

`
`US. Patent
`U.S. Patent
`
`Nov. 20, 2012
`Nov. 20, 2012
`
`Sheet 1 of5
`Sheet 1 of5
`
`US 8,314,356 B2
`US 8,314,356 B2
`
`Ex. C&D 1005, page 2
`
`Ex. C&D 1005, page 2
`
`

`
`US. Patent
`U.S. Patent
`
`Nov. 20, 2012
`Nov. 20, 2012
`
`Sheet 2 of5
`Sheet 2 of5
`
`US 8,314,356 B2
`US 8,314,356 B2
`
`FL'g‘ZA
`
`[-15.25
`
`(HP
`
`Ex. C&D 1005, page 3
`
`Ex. C&D 1005, page 3
`
`

`
`US. Patent
`U.S. Patent
`
`Nov. 20, 2012
`Nov. 20, 2012
`
`Sheet 3 of5
`Sheet 3 0f 5
`
`US 8,314,356 B2
`US 8,314,356 B2
`
`Ex. C&D 1005, page 4
`
`Ex. C&D 1005, page 4
`
`

`
`US. Patent
`U.S. Patent
`
`Nov. 20, 2012
`Nov. 20, 2012
`
`Sheet 4 of5
`Sheet 4 of5
`
`US 8,314,356 B2
`US 8,314,356 B2
`
`Ex. C&D 1005, page 5
`
`Ex. C&D 1005, page 5
`
`

`
`US. Patent
`U.S. Patent
`
`Nov. 20, 2012
`Nov. 20, 2012
`
`Sheet 5 of5
`Sheet 5 of5
`
`US 8,314,356 B2
`US 8,314,356 B2
`
`Ex. C&D 1005, page 6
`
`Ex. C&D 1005, page 6
`
`

`
`US 8,314,356 B2
`
`1
`SPOT WELDING CAP CHANGER
`
`The invention relates to a spot Welding cap changer With a
`cap extractor and tWo cap magazines, the cap extractor having
`a gripper With spring-loaded, pivoting jaws, Which in
`response to a turning and axial extraction movement detaches
`a spot Welding cap of a pincer spot Welding head inserted into
`it from a shaft of the pincer Welding head in such a Way that
`it is clamped to prevent tWisting,
`and the cap magaZines holding spot-Welding caps in a cap
`carrier in such a Way that they are circularly arranged in a
`directed and oriented manner and are one by one transported
`by an advancing force against a stop, into an access position
`alloWing to attach them axially to the free shaft of the pincer
`and to extract them With it.
`Such a mechanical electrode cap changer is knoWn from
`the DE 102 22 248 Al. It has a tWo-part cap extractor, acces
`sible from both sides, in a body separate from the magaZine.
`Since gravity causes the caps to slide against a cap stop, the
`device can only be operated stationary in the vicinity of a
`mobile Welding robot. Changing caps at a stationary pincer
`spot Welding head, to Which each component is fed by a robot
`for Welding, is therefore not possible. The pincer spot Welding
`heads/Welding installations often have short shafts, Which are
`for instance curved, so that the cap extractor, equipped With
`three large jaWs and accordingly big, cannot be positioned for
`extraction.
`It is the object of the invention to provide for an automatic
`faster and safer exchange of the spot Welding caps both at
`mobile and stationary spot Welding installations With a short
`access distance.
`The solution resides in that the cap extractor has tWo
`opposed grippers, each With jaWs that are open at their ends
`and can be rotated toWards each other With approximately
`parallel toothed grip surfaces Whose distance is slightly
`smaller than a diameter of a spot Welding cap, and each cap
`magaZine contains a cap carrier, Which, driven by a spring
`box, presses by Way of its advancing force one of the caps
`respectively against the stop, and in the access position a rim
`overlap overlaps the cap on one side.
`Advantageous forms of the invention are indicated in the
`subclaims.
`In the neW embodiment the cap extractor and the magaZine
`are mounted on a support Which preferably is spring
`mounted. In contrast to the knoWn system, the neW construc
`tion design gives the possibility not only to be used at Welding
`robots, but also at stationary pincer Welding heads or Welding
`installations.
`Compared With the knoWn clamping system With three
`jaWs, the neW cap-extraction installation provides for shorter
`clamp and spin travels, therefore much shorter intervals for
`detaching the caps. Moreover, from the smaller design results
`a Wider array of application, for instance at non-standard
`pincers or very short, curved shafts.
`The tWo cap extractors are each open at the ends of the jaWs
`and thus accessible to a cap. The jaWs grip it directly by Way
`of the undersiZe of their distance and detach the cap, Whereby
`a rotation around an angle of about 30-60° su?ices. This Way
`a cap change is possible even in extremely narroW con?nes.
`Since the tWo grippers are oriented in opposite directions,
`respectively one of them is accessible from the various sides
`in a clockWise rotation, so that no turning of the pincer is
`necessary, even if the pincer shafts are screWed on.
`Furthermore, the round magaZine is much more compact
`than the straight magaZine functioning by gravity of the
`knoWn installation. It can be held and operated in any position
`because of the spring drive.
`
`20
`
`25
`
`30
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`35
`
`40
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`45
`
`50
`
`55
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`60
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`65
`
`2
`Furthermore, the tWo round magaZines arranged on paral
`lel axes provide in each case for an access With short radial
`travel to the access positions in the access openings. In an
`embodiment With a magaZine cover, this cover is directly
`shifted during access, far enough to let the rim overlap
`uncover the cap frame, so that the detaching is possible. The
`example shoWs a radial infeed and an axial access of the shafts
`into the magaZine.
`Both partial devices, the cap changer, and the cap maga
`Zine, are mounted on a support close to one another, and thus
`can be set up stationary, or mounted to a robot arm in a ?xed
`or detachable manner. In the ?rst case the Welding robot
`changes the caps of its oWn pincer, and in the second case the
`robot changes the caps at the stationary pincers or installa
`tions respectively by means of the device. The changing
`device at the robot arm is movably mounted, constantly ready
`for operation in a free space next to the gripper of the robot or
`on a guide rail, or it is located in a parking position, Where it
`can be picked up and brought to operation by the gripper; this
`is called alternating pincer principle.
`Advantageously, cap sensors are arranged on the device.,
`Which indicate Whether a cap is in place or not. Moreover, the
`charging level of the magaZines is monitored. This Way it is
`ensured that after a cap change a cap is in place at the shaft of
`the pincer Welding head before the cooling Water is sWitched
`on. Furthermore it can be veri?ed, Whether the old cap Was
`removed, When it is reported that there is no cap inplace While
`the shaft is approaching.
`The embodiment of the cap magaZine Without a cover
`holds the Welding caps in an elastic cap carrier in a close ?t,
`axially movable by propulsive or tractive force.
`Advantageous embodiments are represented in the FIGS. 1
`to 6.
`FIG. 1 shoWs the entire device schematically and in per
`spective;
`FIG. 2 shoWs a transparent top vieW of the cap extractor;
`FIGS. 2A, 2B shoW detailed enlargements of the grip sur
`faces;
`FIG. 3 shoWs a perspective of the cap extractor;
`FIG. 4 shoWs a cap magaZine in perspective, closed,
`enlarged
`FIG. 5 shoWs a cap magaZine in perspective, open,
`enlarged
`FIG. 6 shoWs a top vieW of the magaZine cover.
`FIG. 1 shoWs a complete spot Welding cap changer 1,
`Which is movably held on a support rail 5 at a robot arm.
`Alternatively, it is ?rmly mounted With the mounting plate 50.
`The bilaterally equipped cap extractor 2 is bolted at the free
`end of the mounting plate 50, With the tWo grippers 20 respec
`tively on the sides, their direction opposite to one another.
`Pulled off caps K are depicted betWeen the jaWs 21, 22, after
`being detached at the rim of a storage container they drop into
`it.
`
`Offset to the rear from the cap extractor 2 respectively one
`cap magaZine 3, 3A laterally offset to the other is mounted on
`the mounting plate 50, With the magaZine cover 4 respectively
`directed laterally and the access openings 40 oriented axially
`parallel to the extracted Welding caps K that are still held by
`the gripper, so that the shafts of the pincer spot Welding head
`have to travel only short distances While changing the caps.
`FIG. 2 shoWs a top vieW on the cap extractor 2, Which
`consists of very feW parts. The grippers 20 are composed of
`one ?xed, toothed jaW 21 respectively, and one jaW 22 Which
`is mounted in such a Way that it can be pivoted toWards said
`jaW 21. The pivot joint 24 is located behind the ?xed jaW 21 by
`Way of a U-shaped structure of the movable jaW arm 25, so
`
`Ex. C&D 1005, page 7
`
`

`
`US 8,3l4,356 B2
`
`3
`that a cap K positioned in the gripper 20 Will be clamped at a
`tWist depending on the direction of rotation.
`The initial pressing force ofthejaWs 21, 22 is caused by a
`bracing spring 26, Which for example, is formed as a spiral or
`bracing spring With spread ends, each pressing against a jaW
`arm 25.
`On the infeed side the grippers 20 are provided With infeed
`skeWs 27, 28. From these extend the roughly parallel grip
`surfaces 23, each With a toothing in opposite direction 29A,
`29B, as FIGS. 2A and 2B shoW in partial vieW and in detail.
`If there is no cap K inserted in the grippers 20, then the
`distance A of the grip surfaces 23 has a minor undersiZe
`compared to the cap outside diameter D.
`FIG. 3 shoWs that the spring 26 and the movable jaWs 21, 22
`as Well as a jaW plate 62, on Which the ?xed jaWs 21 are
`formed, are held betWeen tWo cover plates 60, 61. The jaW
`plate 62 has a corresponding cavity, in Which the U-shaped
`jaW arms 22 have free space to move.
`FIG. 4 shoWs a round cap magaZine 3, Which consists of a
`barrel shaped cap carrier 31, closed With a magaZine cover 4,
`Whereas a radial section remains free up to the rounded access
`opening 40, in Which a Welding cap K in the WithdraWal
`position is pressed to the edge of a stop 32 at the cover.
`The cover 4 has a small rim overlap 41 of the cap frame in
`the curve of the access opening 40, an induct skeW 42 con
`necting to said rim overlap Which is cascaded to the top side
`of the cover. At an embodiment With a hinged cover 4, a slot
`43 is formed, through Which reaches a bracket 34, bevelled on
`the outside, Which keeps the cover 30 shut.
`On the other side of the access opening 40 a hinge 44 With
`a slotted hole 45 is formed in the extension level of the cover,
`the cones 46 of said hinge being held in a hinge support 47.
`FIG. 5 shoWs the open round magaZine 3 With a hinge and
`equipped With a Welding cap K in the drill holes 30 of the cap
`carrier 31, the cap K protruding by a feW millimetres.A ?rmly
`mounted spring box 33, schematically depicted, is in the
`centre of the cap carrier 31, said spring box carrying the
`bracket 34 so that it can be radially moved. A preloaded
`spindle or spiral spring is arranged centrally in the spring box
`33, one end of the spring being ?xed to the spring box 33, the
`other to the cap carrier 31, so that the latter is pressed With a
`torsion force P in the direction of the stop 32, Which extends
`radially on the magaZine cover.
`The plate-shape bracket 34 extends in a diagonal guiding
`slot on the cover of the spring box 33. In the closed state, as
`shoWn here, a compression spring arrangement 35, held in the
`cover, extends from the bracket 34 and is supported by means
`of a support pin 36 on the rounded hinge support 47, and
`presses the bracket 34 in the closed position, in Which it
`overlaps the cover 4 in the closed state and holds the rim
`overlap 41 in the overlap position, the cone 46 being in the
`rear stop position in the slotted hole 45, as FIG. 1 shoWs. To
`open the cover 4, the bracket 34 is pushed back manually.
`Alternatively, the round magaZine can be implemented With
`out a hinge for the opening of the cover. In this case the cover
`is only held in a movable manner, so that the shaft of the
`pincer, When inserted, slides the cover by the skeW 42 to
`release the rim overlap.
`FIG. 6 shoWs a top vieW on the magaZine cover 4, Whose
`main outline consists of tWo semi-circles With shifted centres
`M1, M2, Whereby on one side the access opening 40 extends
`in the direction of the centre, and on the opposite side the
`hinge 44 extends on the outside. The slot in the cover 43
`extends 4 in the central area in the direction betWeen the
`access opening 40 and the hinge 44. The bracket 34 in the
`cover and in the ?xed spring box 33 is guided in this direction.
`The cover 4 is about 15 mm high and largely holloW shaped
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`4
`and has a stiffening cover rim 48, Which passes into the stop
`32 and on the other side into the hinge 44. The cover 4 is
`loWered at the induct skeW 42 by about 5 mm to the infeed
`area. Internally, the cover surface drives the caps to the With
`draWal level When turned in the stop position. A chamber 49,
`Which contains the compression spring arrangement 35, is
`represented With a dashed outline.
`The compact construction of the cap extractor With the
`magaZines alloWs for a signi?cant reduction of the changing
`times, for example, from 22 to 17 sec, Which corresponds to
`about 23%.
`List of Reference Signs
`1 spot Welding cap changer
`2 cap extractor
`20 gripper
`21, 22 jaWs
`23 grip surfaces
`24 pivot joint
`25 jaW arm
`26 bracing spring
`27, 28 infeed skeWs
`29A, 29B toothing
`3, 3A cap magaZine
`30 drill holes
`31 cap carriers
`32 stop
`33 spring box
`34 bracket
`35 compression spring
`36 support pin
`4 magaZine cover
`40 access opening
`41 rim overlap
`42 induct skeW on the cover
`43 slot in the cover
`44 hinge
`45 slotted hole in the hinge
`46 cones
`47 hinge support
`48 cover rim
`49 compression spring chamber
`5 support rail
`50 mounting plates
`60, 61 cover plates
`62 jaW plate
`A gripping jaW distance
`D outside diameter of the caps
`K cap
`P advancing force
`M1, M2 semicircle, centres
`The invention claimed is:
`1. Spot Welding cap changer With a cap extractor and tWo
`cap magaZines the cap extractor having a gripper With spring
`loaded, pivoting jaWs Which in response to a turning and axial
`extraction movement detaches a spot Welding cap (K) of a
`pincer spot Welding head inserted into the pivoting jaWs from
`a shaft of the pincer Welding head in such a Way that caps are
`clamped to prevent the tWisting of the caps, and the cap
`magaZines holding spot Welding caps respectively in a cap
`carrier in such a Way that the spot Welding caps are circularly
`arranged in a directed and oriented manner and are one by one
`transported by an advancing force (P) against a stop, into an
`access position alloWing to attach the spot Welding caps axi
`ally to the free shaft of the pincer and to extract them With the
`shaft of the pincer, characterized in that the cap extractor has
`tWo opposed grippers, each With jaWs that are open at their
`ends and can be rotated toWards each other With approxi
`
`Ex. C&D 1005, page 8
`
`

`
`US 8,314,356 B2
`
`5
`mately parallel toothed grip surfaces a distance smaller than a
`diameter of a spot Welding cap (D or K), and each cap maga
`Zine contains a cap carrier, the cap carrier, driven by a spring
`box, pressing one of the caps respectively by Way of an
`advancing force (P) against the stop, and in the access posi
`tion a rim overlap overlaps the cap (K) on one side.
`2. Spot Welding cap changer according to claim 1, charac
`teriZed in that respectively one of the jaWs of the correspond
`ing gripper is ?xed at a jaW plate, and the corresponding
`movable jaW is formed at an U-shaped jaW arm, Which is
`supported With a pivot joint behind the ?xed jaW.
`3. Spot Welding cap changer according to claim 2, charac
`teriZed in that betWeen the tWo movable j aW arms, a preloaded
`bracing spring is mounted.
`4. Spot Welding cap changer according to claim 1, charac
`teriZed in that the jaWs have infeed skeWs.
`5. Spot Welding cap changer according to claim 4, charac
`teriZed in that the grip surfaces in each case have an asym
`metric toothing, Which on the tWo parallel jaWs is oriented in
`opposite directions.
`6. Spot Welding cap changer according to claim 3, charac
`teriZed in that the jaW arms, the bracing spring and the jaW
`plate are held betWeen cover plates.
`7. Spot Welding cap changer according to claim 1, charac
`teriZed in that the spring box contains a spiral or coil spring,
`one end of the spiral or coil spring is ?xed at the spring box,
`and the other end of the spiral or coil spring is ?xed at the cap
`carrier.
`8. Spot Welding cap changer according to claim 1, charac
`teriZed in that a magaZine cover is held preloaded by a spring
`in the direction of the access opening so that the rim overlap
`overlaps a cap frame in a stop position of a magaZine cover.
`
`20
`
`25
`
`30
`
`6
`9. Spot Welding cap changer according to claim 8, charac
`teriZed in that a bracket is spring-loaded and movably held at
`the spring box, said bracket reaching through the closed
`magaZine cover and, by overlapping the magaZine cover,
`holding the magaZine cover in place.
`10. Spot Welding cap changer according to claim 8, char
`acteriZed in that the magaZine cover is articulated at a hinge
`support, situated opposite of the access opening.
`11. Spot Welding cap changer according to claim 10, char
`acteriZed in that the magaZine cover is movably guided in a
`slotted hole on the hinge support.
`12. Spot Welding cap changer according to claim 1, char
`acteriZed in that the magaZine cover bears a stiffening cover
`rim, Which on one side forms the rim overlap and on the other
`side forms a hinge.
`13. Spot Welding cap changer according to claim 1, char
`acteriZed in that the cap extractor With grippers projecting at
`its front side is mounted on a mounting plate, Wherein on the
`mounting plate With an offset to the rear the cap magaZines
`are mounted.
`14. Spot Welding cap changer according to claim 13, char
`acteriZed in that the access openings of the cap magaZines are
`directed toWards and salient on different sides of the mount
`ing plate, respectively.
`15. Spot Welding cap changer according to claim 13, char
`acteriZed in that the mounting plate is supported and movably
`guided on a support rail Which is mounted on a robot arm.
`16. Spot Welding cap changer according to claim 1, char
`acteriZed in that sensors are arranged at the cap magaZines,
`Which send a signal to a control device When a predetermined
`remaining quantity of spot Welding caps (K) is in stock in the
`respective cap carrier.
`
`*
`
`*
`
`*
`
`*
`
`*
`
`Ex. C&D 1005, page 9