U.S. patent application number 13/721232 was filed with the patent office on 2013-05-02 for method of loading a stud welding head.
This patent application is currently assigned to NEWFREY LLC. The applicant listed for this patent is NEWFREY LLC. Invention is credited to Karl Heinz BRIEHL, Jochen HAIN, Michael SCHNEIDER, Alexander SCHUG.
Application Number | 20130105449 13/721232 |
Document ID | / |
Family ID | 42670356 |
Filed Date | 2013-05-02 |
United States Patent
Application |
20130105449 |
Kind Code |
A1 |
SCHNEIDER; Michael ; et
al. |
May 2, 2013 |
METHOD OF LOADING A STUD WELDING HEAD
Abstract
A method for feeding a component to a component holder and for
joining the component onto a work piece in a joining direction, the
method comprising the steps of: turning the component holder to a
transfer position in which the component holder is aligned with a
feed channel, wherein it is turned about an axis that is aligned
transversely relative to the joining direction; feeding the
component, through the feed channel, into the component holder;
turning the component holder to a joining position; and performing
a joining operation, including moving a slide bearing the component
holder in the joining direction.
Inventors: |
SCHNEIDER; Michael;
(Lahnau-Atzbach, DE) ; BRIEHL; Karl Heinz;
(Rossberg, DE) ; SCHUG; Alexander; (Staufenberg,
DE) ; HAIN; Jochen; (Eschenburg, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NEWFREY LLC; |
Newark |
DE |
US |
|
|
Assignee: |
NEWFREY LLC
Newark
DE
|
Family ID: |
42670356 |
Appl. No.: |
13/721232 |
Filed: |
December 20, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12769921 |
Apr 29, 2010 |
8344280 |
|
|
13721232 |
|
|
|
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Current U.S.
Class: |
219/99 |
Current CPC
Class: |
Y10T 29/49828 20150115;
B23K 9/206 20130101; Y10T 29/53061 20150115; Y10T 29/4978 20150115;
B23K 9/20 20130101 |
Class at
Publication: |
219/99 |
International
Class: |
B23K 9/20 20060101
B23K009/20 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 29, 2009 |
DE |
102009019130.5 |
Claims
1. A method for feeding a component to a component holder and for
joining the component onto a work piece in a joining direction, the
method comprising the steps of: turning the component holder, on a
slide, to a transfer position in which the component holder is
aligned with a feed channel, wherein it is turned about an axis
that is aligned transversely relative to the joining direction;
feeding the component, through the feed channel, into the component
holder; turning the component holder to a joining position; and
performing a joining operation, the slide being moved in the
joining direction.
2. A method according to claim 1, wherein the feeding of the
component through the feed channel into the component holder is
effected in an uninterrupted manner.
3. A method according to claim 1, wherein, when a first component
holder is turned to the joining position, a second component holder
is turned to a transfer position.
4. A method for feeding a component to a component holder and for
joining the component onto a work piece, the method comprising the
steps of: providing a joining head arrangement comprising: a
housing; a linear drive located on the housing; a slide mounted on
the housing and drivable by the linear drive in a joining
direction, one of toward and away from the work piece; a component
holder operable to releasably hold the component during a joining
operation, the component holder mounted on the slide and rotatably
about an axis that is aligned transversely relative to the joining
direction; a feed device including a feed channel for feeding the
component to the component holder, and the component holder is
rotatable between a transfer position, where the component is
transferable from the feed device to the component holder at a
transfer location, and a joining position, where the component is
joinable to the work piece. turning the component holder to the
transfer position in which the component holder is aligned with the
feed channel; feeding the component, through the feed channel, into
the component holder; turning the component holder to the joining
position; and performing a joining operation, including moving the
slide in the joining direction.
5. A method for feeding a component to a component holder and for
joining the component onto a work piece according to claim 4, and
wherein: providing the joining head arrangement further includes
that the component holder is a first component holder mounted at a
first circumferential position on the shaft, and the joining head
arrangement further includes a second component holder mounted at a
second circumferential position on the shaft, and the first
circumferential position is angularly separated from the second
circumferential position; and turning the component holder to the
transfer position in which the first component holder is aligned
with the feed channel further includes turning the second component
holder to the joining position.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of U.S. patent
application Ser. No. 12/769,921, filed Apr. 29, 2010, and now
issued as U.S. Pat. No. 8,344,280 on Jan. 1, 2013, which claims
priority from German Patent Application No. 10 2009 019 130.5,
filed on Apr. 29, 2009, the disclosure of which is incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a joining head arrangement
for joining components, such as studs, onto workpieces, such as
metal sheets, comprising a housing and a slide that is mounted on
the housing and is movable in a joining direction in relation to
the housing by means of a linear drive, comprising at least one
component holder, which is arranged on the slide and at which a
component can be held during a joining operation, and comprising at
least one feed device for feeding components, a component being
transferred, at a transfer location, from the feed device to the
component holder.
[0003] Further, the present invention relates to a method for
feeding a component to a component holder and for joining the
component onto a workpiece in a joining direction.
[0004] A joining head arrangement of the type described above is
known, for example, from the document EP 1 495 828 B1.
[0005] In the present context, the term joining is intended to
refer to all types of connection of elements, such as fastening
elements, on workpieces, such as metal sheets, including adhesive
bonding, forming, such as, for example, riveting, or combining of
materials, such as, for example, welding. In particular, the term
joining is intended here to relate to the joining of rotationally
symmetrical components, such as studs, onto workpieces that are to
be connected to the respective workpiece by, for example,
short-time arc welding (stud welding) and/or by thermoplastic
connection methods such as thermoplastic bonding or thermoplastic
welding.
[0006] The components can be studs that have a shank and a head, or
flange portion, having a somewhat greater diameter than the
shank.
[0007] In the domain of stud welding, i.e. welding of metallic
studs onto metal sheets, there is known the practice of feeding the
studs to a joining head arrangement in an automated manner by means
of a feed device.
[0008] In the case of the joining head arrangement known from the
above-mentioned document EP 1 495 828 B1, the feeding of singled
studs to the joining head arrangement is effected by compressed
air. The stud holder is realized as a collet, which can be widened
to a diameter of at least the flange diameter. The studs are fed
into the holding device from behind, with the flange portion
foremost, until the flange portion has emerged axially from the
collet and the collet continues to hold only the shank of the stud.
Starting from this position, a stud welding operation can then be
performed, which operation can comprise, for example, the stages of
placing the flange portion onto the workpiece, passing a pilot
current through the stud and the workpiece, then raising the stud
from the workpiece in order to draw an arc, switching over to a
welding current, such that the mutually opposite surfaces of flange
portion and workpiece become fused, and, finally, lowering the stud
back onto the workpiece, until the arc is extinguished. At
approximately the same time, the welding current is switched off,
such that the combined melt solidifies and the stud is connected to
the workpiece by material bonding.
[0009] Problematic in the case of the above joining head
arrangement is that the component holder is subject to a large
amount of wear. This is due to the elastic clamping elements of the
component holder becoming overstretched by the relatively large
cross-section of the flange portion.
[0010] A further joining head arrangement is known from the
document DE 10 2005 044367 A1 (corresponds to publication
US2007/0067975), which is under common ownership with this
application and the disclosure of which is incorporated herein by
reference.. In the case of this arrangement, a housing, on which a
slide is mounted in a linearly moveable manner, is rotatably
mounted on an elongate arm. The feed device is fixed to the arm,
and terminates in a transfer station. The housing can be so turned
in relation to the arm that a stud, made available at the transfer
station, is received there, in order subsequently to perform a
joining operation with the received stud and following turning back
to a joining position. In the case of this joining head
arrangement, the cycle times are relatively long. In addition, the
component holder is of relatively complex design, to enable the
studs made available at the transfer station to be received in a
reliable manner.
BRIEF SUMMARY OF THE INVENTION
[0011] Against the above background, it is the object of the
invention to specify a joining head arrangement and a joining
method, by means of which arrangement and method relatively short
cycle times can be achieved and wherein the component holder can be
of a simple structure.
[0012] The above object is achieved, in the case of the joining
head arrangement mentioned at the outset, in that the component
holder is rotatable, on the slide, about an axis that is aligned
transversely relative to the joining direction, in such a way that
the component holder can be turned between the transfer location
and a joining position.
[0013] Further, the above object is achieved by a method for
feeding a component to a component holder and for joining the
component onto a workpiece in a joining direction, comprising the
steps:
[0014] turning the component holder, on a slide, to a transfer
position in which the component holder is aligned with a feed
channel, wherein the component holder is turned about an axis that
is aligned transversely relative to the joining direction;
[0015] feeding the component, through the feed channel, into the
component holder;
[0016] turning the component holder to a joining position; and
[0017] performing a joining operation, the slide being moved in the
joining direction.
[0018] In the case of this joining head arrangement, or this
joining method, it is particularly advantageous that high, i.e.
short cycle times, can be achieved, depending on the embodiment.
Further, the component holder can be of a structurally simple
design. This applies, in particular, when studs having a flange
portion are to be joined. These studs, at the transfer location,
can be transferred with the shank foremost into the component
holder, such that overstretching of the stud holder can be
prevented. The service life of the component holder can thereby be
prolonged substantially.
[0019] The object is thus achieved in full.
[0020] It is particularly advantageous if the transfer location is
fixed in relation to the housing or the slide. Fixing to the
housing is particularly preferred in this case, since the feed
device need not therefore be moved concomitantly in the region of
the transfer location.
[0021] According to a further preferred embodiment, a shaft is
rotatably mounted on the slide, on which shaft the component holder
is so fixed that a component held thereon is aligned transversely
relative to the shaft.
[0022] Turning of the component holder can thereby be realized in a
structurally simple manner.
[0023] It is particularly advantageous in this case if there are
fixed on the shaft at least two component holders that are arranged
so as to be distributed over the circumference of the shaft.
[0024] In the case of this embodiment, it is advantageous that very
high cycle times can be achieved, since, during a joining operation
in which one of the component holders is being used, a further
component to be joined can be fed to the other component holder, at
the transfer location. Following completion of the joining
operation, the further component can then be joined by turning the
shaft. The first-mentioned component holder is then located at the
transfer location, and can receive a further component.
[0025] This parallel operation enables the cycle times to be
improved significantly.
[0026] It is further of particular advantage in this case if at
least two feed devices are provided, such that a component can be
transferred from the respective feed device to a respective
component holder at at least two transfer locations.
[0027] In the case of this embodiment, differing components (for
example, of differing shank length or differing flange diameter)
can be made available, on the one hand, by the feed device. It is
particularly preferable if, in this case, at least three component
holders are fixed to the shaft, which component holders are
arranged so as to be distributed over the circumference of the
shaft. In the case of this embodiment, a component can be
transferred to a respective component holder at at least two
transfer locations in a rotary position of the shaft, whilst a
further component is held by the third component holder for the
purpose of performing a joining operation therewith.
[0028] Overall, it is further advantageous if a drive device is
fixed to the slide for the purpose of turning the component
holder.
[0029] The turning of the component holder, for example by turning
the shaft, can thereby be realized in a structurally simple
manner.
[0030] It is particularly advantageous in this case if the
component holder is arranged at one end of the shaft and the drive
device is arranged at the other end of the shaft.
[0031] In the case of this arrangement, it is possible to achieve a
situation whereby the drive unit does not constitute an additional
interfering contour.
[0032] It is particularly advantageous if the drive device has an
electric motor, which can be realized, for example, as a stepping
motor.
[0033] It is particularly advantageous if the electric motor is
arranged concentrically relative to the shaft.
[0034] An output shaft of the electric motor can thereby be
directly connected to the shaft to which the at least one component
holder is fixed.
[0035] In the case of the method according to the invention, it is
advantageous if the feeding of the component through the feed
channel into the component holder is effected in an uninterrupted
manner.
[0036] In the case of this embodiment, there is no provision, for
the purpose of making available the component, of a transfer
station at which the component comes to a standstill and is then
"collected" by the respective component holder. Rather,
particularly in the case of the feed channel being aligned with the
stud holder at the transfer location, a stud can be passed directly
from the feed channel into the component holder, for example, by
compressed air or the like, without intermediate stopping.
[0037] As a result of this measure, the component holder can be
realized in a structurally simple manner, for example, as a
substantially cylindrical collet, into which the shank of the stud
is inserted. Such a cylindrical stud holder can be realized with at
least one longitudinal slot, preferably with a plurality of
longitudinal slots, in order to provide the necessary radial
elasticity.
[0038] In the case of the method according to the invention, it is
further advantageous, for the purpose of improving the cycle time,
that, when one component holder is turned to the joining position,
at least one further component holder is turned to a transfer
position.
[0039] A joining operation and a feed operation can thereby be
performed substantially in parallel.
[0040] It is understood that the above-mentioned features and those
to be explained in the following can be applied, not only in the
respectively specified combination, but also in other combinations
or singly, without departure from the scope of the present
invention.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0041] Exemplary embodiments of the invention are represented in
the drawing and explained more fully in the following description,
wherein:
[0042] FIG. 1 shows a schematic view of a joining system comprising
a joining head arrangement according to the invention;
[0043] FIG. 2 shows an alternative embodiment of a joining head
arrangement according to the invention;
[0044] FIG. 3 shows a perspective view of a further alternative
embodiment of a joining head arrangement according to the
invention; and
[0045] FIG. 4 shows a schematic side view of a further joining head
arrangement according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0046] In FIG. 1, a joining system is denoted in general by the
reference 10. In the present case, the joining system 10 is
designed for stud welding in the drawn arc ignition process.
Alternatively, the joining system can also be designed for other
joining processes, such as, for example, thermoplastic welding or
adhesive bonding.
[0047] The joining system 10 comprises a robot 12 having a fixed
base 14, mounted on which, in an articulated manner, is a first arm
16, at the free end of which a second arm 18 is mounted in an
articulated manner.
[0048] Fixed to the free end of the second arm 18 is a joining head
arrangement 20. The joining head arrangement 20, however, can also
be part of a manually actuable welding gun or the like.
[0049] By means of the robot 12, the joining head arrangement 20
can be moved to various locations. Preferably, but not exclusively,
such a joining system is used in motor vehicle engineering, being
so used to join studs onto vehicle-body metal sheets. Studs fixed
to the vehicle-body metal sheet in such manner can be used as
anchors for plastic clips for fastening lines or the like, for
locking in place mount-on parts, such as facings, etc.
[0050] Represented in FIG. 1 is a workpiece 24 in the form of a
metal sheet, to which a component, in the form of a stud 22, has
been joined by means of the joining system 10. The stud 22
comprises a shank 26 and a flange portion 28, which has a greater
diameter. The stud in this case is so joined to the workpiece 24
that the shank 26 projects approximately perpendicularly relative
to a surface of the work-piece, and consequently can serve as a
fastening element, as an anchor or the like.
[0051] The joining head arrangement 20 comprises a housing 30,
which is fixed to the free end of the second arm 18. A slide 32 is
mounted in a linearly displaceable manner on the housing 30.
Further provided on the housing 30 is a linear drive 34,
represented schematically, by means of which the slide 32 can be
moved in a linear direction (joining direction) 36 in relation to
the housing 30. The linear drive can be an electric linear motor,
although the linear drive 34 can also comprise a mechanical drive,
such as a spring.
[0052] A component holder 38 is mounted on the slide 32 so as to be
rotatable about a rotational axis 40. The rotational axis 40 is
aligned transversely, in particular, perpendicularly in relation to
the joining direction 36.
[0053] In FIG. 1, the component holder 38 has been turned to a
transfer position in which the stud holder 38, which is aligned
perpendicularly relative to the rotational axis 40, is in alignment
with a feed device 42. The feed device 42 is connected to a
singling device 44, in which studs 22 that are provided as bulk
material are singled and then conveyed singly from the fixed
singling device 44 to the joining head arrangement 20, for example
by compressed air.
[0054] The joining system 10 further comprises a supply device 46,
which can provide, for example, a welding voltage and control
signals for operating the joining head arrangement 20. The supply
device 46 is connected, via a first cable loom 48, to a control
device 52 in the housing 30. Further, the control device 52 can be
connected, via a second cable loom 50, to the base 14 of the robot
12. In addition, the supply device 46 and the base 14 can be
connected to one another via a third cable loom 54. The welding
voltage required for stud welding is provided via the first cable
loom 48. Further, coordination of the movements of the robot 12 and
of the slide 32 in relation to the housing 30 is effected via the
cable loom 48 and via the other cable looms.
[0055] The feed device 42 comprises a feed channel 58, for example
in the form of a flexible tube, through which the components 22 can
be conveyed, by means of air pressure 56, to the joining head
arrangement 20, as indicated by a component 22'. In the present
case, the feed channel 58 is fixed to the slide 32, and terminates
in the region of a transfer location 60. The transfer location 60
is so arranged that the stud holder 38 can be thereby aligned by
turning about the rotational axis 40. It is thereby possible for a
component to be conveyed, substantially in an uninterrupted manner,
from the feed channel 58, by means of the compressed air 56, into
the thereby aligned component holder 38 in a transfer position. In
this case, the stud is transferred with its shank foremost into the
stud holder 38, such that the clamping elements of the latter need
not be widened to the diameter of the flange portion 28. The stud
is then held in the stud holder 38 by a radially elastic action, as
represented for a component 22'' in FIG. 1.
[0056] From this position, the component holder 38 is subsequently
turned to a joining position, as indicated by an arrow. The joining
position can be aligned, for example, diametrically in relation to
the transfer location, such that the stud holder 38 is displaced by
180.degree. about the rotational axis 40. In the joining position,
the stud is then already being held in the correct position, such
that subsequently thereto the slide 32 can be displaced in relation
to the housing 30, in order to place the stud onto the surface of
the workpiece 24. A pilot current is then passed through the stud
holder 38, the component 22 held thereon and through the workpiece
24. The stud 22 is thereafter raised back from the surface of the
workpiece 24 by means of the slide 32, such that an arc is drawn.
The electric current is then increased to a welding current, which
can be in the region >1000 A. The mutually opposite surfaces of
the component 22 and of the workpiece 24 thereby undergo fusion. By
means of the linear drive 34, the slide 32 is then lowered back
onto the workpiece 24, such that the melts become mixed. The
welding current is switched off. The combined melt solidifies, such
that the stud 22 is then materially bonded to the workpiece 24.
[0057] The slide 32 is then moved back, and the stud holder 38 is
turned back to the transfer location 60, in order to receive a new
stud 22'. A new joining operation, in the form of a stud welding
process, is then performed.
[0058] Represented in FIGS. 2 to 4 are further embodiments of
joining head arrangements according to the invention, which
correspond in general to the joining head arrangement 20 of FIG. 1
in respect of structure and functioning. Elements that are the same
are therefore denoted by the same reference numerals. In the
following, it is, in essence, the differences that are
explained.
[0059] In the case of the joining head arrangement of FIG. 2, two
stud component holders 38A, 38B are provided, aligned diametrically
in relation to the rotational axis 40. When the one stud holder is
in the transfer position at the transfer location 60, the other
stud holder is in the joining position. Consequently, the feeding
of a component to one of the stud holders (in FIG. 2, the stud
holder 38B, to which a component 22'' has been supplied) and the
joining of a component 22''' that is held at the other stud holder
(in FIG. 2, the component holder 38A) can be performed
substantially in parallel with one another.
[0060] Further, in the case of the joining head arrangement 20 of
FIG. 2, the feed channel 58 is not fixed to the slide 32, but to
the housing 30. It is thereby possible to achieve a situation
whereby the feed channel 58 need not be moved concomitantly with
movements of the slide 32. Consequently, a less wearing type of
operation can be achieved.
[0061] Shown in FIG. 3 is a further joining head arrangement 20, in
which a shaft 62 is mounted on the slide 32 so as to be rotatable
about the rotational axis 40. The shaft 62 can be driven in both
directions of rotation by means of a drive motor 64 in the form of
an electric motor. The electric motor is arranged coaxially
relative to the shaft 62, at one end thereof. At the other end,
three stud holders 38A, 38B, 38C are fixed to the shaft,
distributed over the circumference. The component holders are each
realized as cylindrical collets, which are provided with one or
more longitudinal slots 66. Further, the thereby constituted collet
elements can be held by a retaining ring 68 (for example, of metal
or in the form of an O-ring), or be realized with radially elastic
deformability in the radial direction (in relation to the feed
direction).
[0062] The joining head arrangement 20 further has a first feed
device 42A and a second feed device 42B comprising, respectively, a
first feed channel 58A and a second feed channel 58B. The feed
channels 58A, 58B are so aligned to the shaft 62 that there are
defined two transfer locations 60A, 60B, which are spaced apart
from one another in the circumferential direction, and which are
aligned, in relation to one another, at an angle that corresponds
to the angular division of the component holders 38 on the shaft
62. In the present case, the angle is 120.degree. (corresponding to
360.degree. divided by three component holders 38). In the case of
this arrangement, one of the component holders 38A is in the
joining position, and holds a component 22'''. A second component
holder 38B is in a second transfer position aligned with the second
transfer location 60B. A third stud holder 38C is in a first
transfer position aligned with the first transfer location 60A.
[0063] In the case of the joining head arrangement 20 of FIG. 3,
components of differing types (for example, of differing shank
length and/or differing flange diameter) can be fed via the two
feed devices 42A, 42B. The versatility of the joining head
arrangement 20 is thereby increased.
[0064] It is understood that, instead of three stud holders, it is
also possible for four or more stud holders to be fastened to the
shaft 62, which stud holders are preferably uniformly spaced apart
from one another in the circumferential direction. Correspondingly,
it is also possible for more than two feed devices 42 to be
provided, which devices are then arranged according to the
positions of the stud holders that are not actually in the joining
position.
[0065] The shaft 62 is preferably electrically conductive. The stud
holders are also each electrically conductive, such that a
respective electric current, for switching on a pilot current and a
welding current, can be supplied via the shaft and the stud
holders. A sliding contact, or a contact arrangement that can be
closed and disconnected, such that a contact is established
whenever a component 22 is to be joined to a workpiece, can be
provided for the purpose of transferring the electric current from
the housing 30, or the slide 32, to the shaft 62.
[0066] A further joining head arrangement 20 is shown in FIG. 4.
The joining head arrangement 20 has a rigid, elongate arm 70, at
the end of which a housing 30 is mounted so as to be rotatable
about a head rotational axis 72. Again, as in the case of the above
embodiments, a slide 32 is movable on the housing 30 so as to be
axially displaceable in the joining direction 36. Two stud holders
38A, 38B, spaced apart angle-wise, are mounted on the slide 32 so
as to be rotatable about a rotational axis 40.
[0067] In the case of this embodiment, studs are fed via a feed
device 42, being so fed into the arm 70. There, the studs, or
components, are stopped and made available in a transfer station
74, as shown in FIG. 4 for the component 22'. For the purpose of
receiving a component, the housing 30 is firstly rotated about the
head rotational axis 72, and one of the stud holders 38A, 38B is
then aligned with the transfer station 74, in order to receive the
component 22' (in FIG. 4, a component 22''' to be joined is held at
the stud holder 38A, and an already received component 22'' is held
at the stud holder 38B).
[0068] In the case of this embodiment, the supply of components
into the respective stud holder 38 is effected in two stages, i.e.,
not in an uninterrupted manner. Firstly, a component is fed into
the transfer station 74. In a second stage, the component is
transferred from the transfer station 74 into a respective stud
holder 38. A corresponding mechanism is to be provided for this
purpose. If appropriate, the transfer in the stud holder 38 can
also be effected in that the stud holder 38 is aligned with the
transfer station 74 and the slide 32 is then moved in order to push
the respective stud holder onto the stud made available at the
transfer station 74. As an alternative thereto, the stud holders
38A, 38B can also be realized as gripping devices that, in the open
state, can be moved over the shank of a component 22' that is made
available in the transfer station 74.
[0069] Although exemplary embodiments of the present invention have
been shown and described, it will be appreciated by those skilled
in the art that changes may be made to these embodiments without
departing from the principles and spirit of the invention, the
scope of which is defined in the appended claims and their
equivalents.
* * * * *