U.S. patent application number 12/695129 was filed with the patent office on 2010-06-03 for method for the production of hollow elements, hollow element, assembly piece, and follow-on composite tool for carrying out said method.
This patent application is currently assigned to PROFIL Verbindungstechnik GmbH & Co., KG. Invention is credited to Jiri BABEJ, Richard Humpert, Michael Vieth.
Application Number | 20100135744 12/695129 |
Document ID | / |
Family ID | 34964999 |
Filed Date | 2010-06-03 |
United States Patent
Application |
20100135744 |
Kind Code |
A1 |
BABEJ; Jiri ; et
al. |
June 3, 2010 |
METHOD FOR THE PRODUCTION OF HOLLOW ELEMENTS, HOLLOW ELEMENT,
ASSEMBLY PIECE, AND FOLLOW-ON COMPOSITE TOOL FOR CARRYING OUT SAID
METHOD
Abstract
Disclosed is a method for producing hollow elements (200), such
as nut elements, which are to be mounted on parts generally made of
sheet metal, particularly for producing hollow elements having an
at least substantially square or rectangular outer contour (202).
According to said method, individual elements are cut to size from
a profiled member that is provided in the form of a profiled bar or
a reel after punching holes into said profiled member, optionally
followed by embodying a threaded cylinder (206) using a follow-on
composite tool (10) with several workstations (A, B, C, D). The
inventive method is characterized in that a penetrating process, a
punching process, and a flattening process are carried out in the
workstations (A, B, C, D). Also disclosed are hollow elements
(200), assembly pieces, and a follow-on composite tool (10).
Inventors: |
BABEJ; Jiri; (Lich, DE)
; Vieth; Michael; (Bad Vilbel, DE) ; Humpert;
Richard; (Rosbach v,d,H., DE) |
Correspondence
Address: |
Hershkovitz & Associates, LLC
2845 Duke Street
Alexandria
VA
22314
US
|
Assignee: |
PROFIL Verbindungstechnik GmbH
& Co., KG
Friedrichsdorf
DE
|
Family ID: |
34964999 |
Appl. No.: |
12/695129 |
Filed: |
January 27, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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|
10599640 |
Jan 10, 2007 |
7677074 |
|
|
PCT/EP05/03893 |
Apr 13, 2005 |
|
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|
12695129 |
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Current U.S.
Class: |
411/172 ;
411/180 |
Current CPC
Class: |
F16B 37/068 20130101;
B21K 1/68 20130101; B21J 9/022 20130101; B21K 1/702 20130101 |
Class at
Publication: |
411/172 ;
411/180 |
International
Class: |
F16B 37/04 20060101
F16B037/04 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 13, 2004 |
DE |
1020040178666 |
Claims
1. Hollow body element for attachment to a component normally
comprising sheet metal, the hollow body element comprising: one of
an at least substantially square and rectangular outline with a
first broad side and a second broad side forming a sheet metal
contact surface, a piercing section, which projects beyond the
second broad side and has an undercut and is surrounded by a ring
recess having a conical outer surface in the second broad side,
wherein the conical outer surface merges into the second broad
side, an aperture, which extends from the first broad side through
the piercing section, with the aperture optionally having a thread
cylinder, and features providing security against rotation are
formed one of outwardly at the hollow cylindrical projection and
inwardly in a region of the ring recess around the hollow
cylindrical projection.
2. Hollow body element in accordance with claim 1, wherein the
features providing security against rotation are formed by one of
ribs and grooves at a radially outer side of the hollow cylindrical
projection.
3. Hollow body element in accordance with claim 1, wherein the
features providing security against rotation are formed by ribs,
which extend in an axial direction and bridge the undercut of the
hollow cylindrical projection.
4. Hollow body element in accordance with claim 3, wherein the ribs
providing security against rotation have a radial width, which lies
at least substantially in a region between 40% and 90% of a maximal
radial depth of the undercut.
5. Hollow body element in accordance with claim 1, wherein the
features providing security against rotation are provided in the
form of radially extending ribs, which bridge the ring recess.
6. Hollow body element in accordance with claim 1, wherein the
features providing security against rotation are provided in the
form of obliquely set ribs providing security against rotation,
which extend in a radial direction across the ring recess and in an
axial direction along the undercut of the piercing section.
7. Hollow body element in accordance with claim 1, wherein the
features providing security against rotation are provided in the
form of ribs, which extend in a radial direction across the ring
recess and in an axial direction along the undercut of the piercing
section.
8. Hollow body element in accordance with claim 1, wherein the
features providing security against rotation are provided in the
form of recesses, which are arranged in an obliquely set surface of
the ring recess.
9. Hollow body element in accordance with claim 1, wherein the
second broad side lies in a plane radially outside of the ring
recess, and apart from any features at the transitions into the
side flanks of the hollow body element.
10. Hollow body element in accordance with claim 1, wherein an
opening of the cylindrical recess at the first broad side of the
section is executed with one of a rounded and chamfered run-in
edge.
11. Hollow body element in accordance with claim 1, wherein an
opening of the hollow cylindrical projection is provided at its
free end with one of a rounded and chamfered run-out edge.
12. Hollow body element in accordance with claim 1, wherein the
ring recess is provided with a ring-like base region, which stands
at least approximately in a plane parallel to the first and second
broad side, and merges at a radially inner side with an at least
substantially rounded transition into an outer side of the hollow
cylindrical projection and at a radially outer side into a conical
surface.
13. Hollow body element in accordance with claim 1, wherein the
ring recess is executed with an external diameter, which is only
somewhat smaller than a smallest transverse dimension of the hollow
body element, which is rectangular in plan view, whereby the ring
recess forms webs with the second broad side of the section that
remain at narrowest points in a plane of the second broad side in a
range from 0.25 to 1 mm, preferably of approximately 0.5 mm.
14. Component assembly comprising a hollow body element in
accordance with claim 1, which is attached to a component, for
example to a sheet metal part, with the material of one of the
component and the sheet metal part contacting a surface of the ring
recess of the hollow body element at a surface of features
providing security against rotation and also at a surface of the
undercut of the piercing section of the hollow body element, and
with a ring recess being present in the material of one of the
component and the sheet metal part around the piercing section.
15. Component assembly in accordance with claim 14, wherein an
axial depth of the ring groove in the sheet metal part is selected
in dependence on a length of the piercing section and a thickness
of the sheet metal part so that the end face of the piercing
section does not project beyond a side of the sheet metal part,
which is remote from a body of the hollow body element and is
present in a region beneath the second broad side of the hollow
body element around the ring recess of the hollow body element.
16. Component assembly in accordance with claim 14, wherein the
second broad side of the hollow body element is at least
substantially not pressed into the sheet metal material in a region
around the ring recess of the hollow body element.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a division of Ser. No. 10/599,640, filed
Jan. 10, 2007, pending, which is the US national stage of
PCT/EP05/03893 filed Apr. 13, 2005, which claims priority of German
Patent Application No. 10 2004 017 866.6 filed Apr. 13, 2004, the
contents of all of which are incorporated herein in their entirety
by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a method for manufacturing
hollow body elements such as nut elements for attachment to
components normally consisting of sheet metal, in particular for
the manufacture of hollow body elements, having an at least
substantially square or rectangular outline by cutting individual
elements to length from a section present in the form of a profile
bar or of a coil after prior piercing of holes into the section,
optionally with subsequent formation of a thread cylinder using a
progressive tool having a plurality of working stations in each of
which respective operations are carried out. Furthermore the
present invention relates to hollow body elements which are
manufactured in accordance with the method, component assemblies
which consist of a hollow body element and a sheet metal part and
also a progressive tool for carrying out the method.
BACKGROUND OF THE INVENTION
[0003] A method of the initially named kind and also corresponding
hollow body elements and component assemblies are, for example,
known from WO 01/072449 A2. A method of this kind is also known
from U.S. Pat. No. 4,971,499. Rectangular hollow body elements are
also sold by the company Profil Verbindungstechnik GmbH & Co.
KG in Germany under the designation HI rectangular nut.
[0004] The object of the invention is to further develop the method
of the initially named kind such that hollow body elements, in
particular rectangular nut elements can be manufactured at a
favorable prize without loading the tools that are used such that
they prematurely fail. Furthermore, the hollow body elements should
have mechanical characteristics which are at least as good as those
of the hollow body elements which are manufactured in accordance
with WO 01/72449 A2 or in accordance with the German Utility Model
202 05 192.7, for example have a high pullout force, an excellent
security against rotation and which in addition show a reduced
notch effect so that the fatigue characteristics of component
assemblies consisting of a component from sheet metal and hollow
body elements attached to it are also improved under dynamic
loads.
[0005] The object underlying the invention is satisfied by a method
of the initially named kind, which is characterized by the
following steps: [0006] a) in a first step, starting from a section
rectangular in cross-section, an upsetting process is carried out
which leads to a cylindrical recess at a first broad side of the
section and to a hollow cylindrical projection at a second broad
side of the section opposite to the first broad side, the
projection being surrounded by a ring-shape recess, [0007] b) in a
second step, a web remaining between the base of the cylindrical
recess and the base of the hollow cylindrical projection is pierced
or punched out to form a through-going aperture, [0008] c) in a
third step, which can optionally be combined with the step b), the
hollow cylindrical projection is flattened or crushed at its free
end for the formation of a piercing section undercut at the outer
side, whereafter the hollow body element (200) is separated from
the section and optionally provided with thread.
[0009] Furthermore, the present invention provides a hollow body
element for attachment to a component normally consisting of sheet
metal having an in particular at least substantially square or
rectangular outline, with a first broad side and a second broad
side, with a piercing section which projects beyond the second
broad side and has an undercut and is surrounded by a ring recess
in the second broad side and also with an aperture which extends
from the first broad side through the piercing section, with the
aperture optionally having a thread cylinder, characterized in that
features providing security against rotation are formed outwardly
at the hollow cylindrical projection and/or inwardly in the region
of the ring recess around the hollow cylindrical projection.
[0010] In the method of the invention, the section that is thus
used as a rectangular cross-section and can accordingly be
manufactured at favorable price. Through the steps a), b) and c),
one succeeds in manufacturing hollow body elements without the
tools that are used being subjected to a high level of wear and
without the punches that are used failing prematurely. The method
claimed in the German patent application 10204589.5 and also the
corresponding progressive tools described there are also
straightforwardly suited, with an appropriate design of the punches
and dies used for the steps a), b) and c) for carrying out the
present method and for manufacturing the corresponding hollow body
elements.
[0011] The manufacture in working steps in which two operations are
always carried out for one section in one station leads to the
productivity of the manufacturing plant being doubled without the
cost and complication for the manufacture of the progressive tool
arising to a degree which would no longer be worthwhile. The
doubling up of working elements admittedly requires a certain
additional cost and complexity, this can, however, be
straightforwardly amortized relatively early by corresponding
production quantities.
[0012] It is indeed possible to process a plurality of sections in
one progressive tool, this is, however, not necessarily to be
preferred because, if problems arise with one section or with the
processing of one section, the entire progressive tool must be
stopped until the fault has been remedied, whereby considerable
production losses could arise. Nevertheless, the present invention
could be realized using a progressive tool which simultaneously
processes a plurality of sections.
[0013] Particularly preferred embodiments of the method of the
invention, of the hollow body elements of the invention, of the
component assemblies of the invention and also of the progressive
tool of the invention can be found in the further patent
claims.
[0014] Further advantages of the method of the invention, of the
hollow body elements of the invention and also of a progressive
tool used in accordance with the invention can be found in the
drawings and in the subsequent description of the drawings.
[0015] The Figures show:
[0016] FIG. 1 an embodiment of a section which is processed for the
purpose of the present invention in a progressive tool in
accordance with FIG. 2, with
[0017] FIG. 2 showing a progressive tool section in the direction
of movement of the section,
[0018] FIG. 3 an enlarged representation of a progressive tool of
FIG. 2 in the region of the working stations,
[0019] FIGS. 4A-4E a representation of the individual steps for the
manufacture of a hollow body element in accordance with the
invention using the method of the invention and the progressive
tool of FIGS. 2 and 3,
[0020] FIGS. 5A-5N various representations of the finished hollow
body element of FIGS. 4A-4E in accordance with the invention, with
FIG. 5A showing a perspective representation of the hollow body
element of the invention from below, FIG. 5B a plan view of the
hollow body element of the invention from above, FIG. 5C a
sectional drawing corresponding to the section plane C-C or C'-C'
of FIGS. 5B, and 5D an enlarged representation of the region D of
FIG. 5C; the further FIGS. 5E-5I show an ideal variant of the
hollow body element of FIGS. 5A-5D and indeed designed for thicker
sheet metal parts, whereas the FIGS. 5J-5N show a further ideal
variant which is designed for use with thinner sheet metal
parts,
[0021] FIGS. 6A-6E representations of a further hollow body element
in accordance with the invention which represents a slight
modification of the hollow body element in accordance with FIGS.
5A-5D, with FIG. 6A showing a plan view of the hollow body element
from above, FIG. 6B a section drawing along the section plane B-B
of FIG. 6A, FIG. 6C a section drawing in accordance with a section
plane C-C of FIG. 6A, and FIGS. 6D and 6E perspective
representations of the functional element from above and below,
[0022] FIGS. 7A-7B the attachment of the hollow body element of the
invention to a thin sheet metal part and to a thicker sheet metal
part respectively,
[0023] FIGS. 8A-8D representations of a further variant of a hollow
body element with features providing security against rotation in
the form of radially extending ribs which bridge the ring recess,
with FIG. 8A being a view of the hollow body element from below,
the FIGS. 8B and 8C being section drawings corresponding to the
horizontal section plan B-B and to the vertical section plane C-C
of FIG. 8A, and the FIG. 8D being a perspective drawing,
[0024] FIGS. 9A-9D representations corresponding to FIGS. 8A-8D,
but of an embodiment with obliquely set ribs providing security
against rotation which extend in the radial direction across the
ring recess and in the axial direction along the undercut of the
piercing section,
[0025] FIGS. 10A-10D representations corresponding to FIGS. 8A-8D,
but of an embodiment with angled ribs providing security against
rotation which extend in a radial direction across the ring recess
and in the axial direction along the undercut of the piercing
section,
[0026] FIGS. 11A-11D representations in accordance with FIGS.
8A-8D, but of an embodiment with features providing security
against rotation which are formed by grooves or recesses, and
[0027] FIGS. 12A-12D representations corresponding to FIGS. 8A-8D
but of an embodiment with a polygonal ring shape in plan view, of
square shape in the specific case.
[0028] FIG. 1 shows a portion of an elongate section 1 with a
rectangular cross-section, a first broad side 2, a second broad
side 3 and two narrow sides 7, 8. The longitudinal edges 9 of the
section can be rounded as shown. It can, however, also have another
shape, for example a chamfer or a rectangular shape. The section is
processed in a progressive tool in order to manufacture hollow
elements, for example nut elements with an essentially rectangular
or square shape. When the, hollow elements are to be realized as
nut elements a thread must be cut or produced in the aperture of
the hollow body element. This normally takes place outside of the
progressive tool in a separate machine. Furthermore, the
possibility exists of only manufacturing the thread after the
attachment of the hollow body element to a sheet metal part, for
example by means of a thread forming or thread cutting screw.
Furthermore, it is not necessary to provide a thread in the hollow
body element, but rather the aperture of the hollow body element
could serve as a smooth bore for the rotational journaling of a
shaft or as a plug amount to receive a plug-in pin.
[0029] A first progressive tool 10 which serves for the manufacture
of the hollow body elements from the section 21 of FIG. 1 or from a
similar section and which is claimed per se in the German patent
application 102004004589.5 is shown in FIG. 2 in longitudinal
section, with the longitudinal section being taken through the
centre of the section.
[0030] One can see from FIG. 2 a lower plate 12 which is normally
secured to a press table either directly or indirectly via an
intermediate plate, not shown. The lower plate 12 carries a
plurality of columns 14, four in this example, of which two can be
seen, namely the two columns which lie behind the section plane. A
further plate 16 is present above the columns and is normally
secured to the upper tool plate of the press or to an intermediate
plate of the press. Guides 18 are screwed to the plate 16 (for
example by means of screws which are not shown here) with the
guides 18 being designed in order to slide up and down on the
columns 14 in accordance with the stroke movement of the press. The
section 1 is advanced in the arrow direction 20 for each stroke of
the press and indeed by an amount which corresponds to twice the
longitudinal dimension L of the individual hollow body elements
manufactured from the section. One notes that in the representation
in accordance with FIGS. 2 and 3 the section 1 is guided with a
second broad side 3 directed upwardly through the progressive tool.
As can be seen from the enlarged representation of the central
region of the progressive tool of FIG. 3, the progressive tool
includes in this example four working stations A, B, C, D in each
of which two respective operations are simultaneously effected for
each stroke of the press.
[0031] In the first station A a so-called upsetting process takes
place as a first step a).
[0032] In the second working station B, a piercing process is
carried out in a second step b) and a crushing or flattening
process is carried out in the third working station C in a third
step c). Finally, a cut-off punch 22 is used in the fourth working
station D in order to separate two hollow body elements from the
section 1 for each stroke of the press. In doing this, the right
hand side of the punch cuts through the section at a partitioning
point which is located behind the first hollow body element, i.e.
the hollow body element 21 in FIG. 3 and also at a cutting point
behind the second hollow body element 21'. The progressive tool is
shown in FIGS. 2 and 3 in the closed position in which the two
hollow body elements 21 and 21' have just been cut from the section
1. Shortly before the cut-off process, the front side of the nut
element 21 contacts the inclined surface 24 of the right angled cam
27 which is pressed downwardly by a compression coil spring 26. The
advance of the strip of the section thus presses the cam 24
upwardly via its inclined surface, whereby the spring 26 is
compressed. After the first hollow body element 21 has been cut
off, the cam 24 presses on the right hand side of the nut element
21 and tips it into the inclined position which is evident at the
right hand side of FIG. 3. The nut element 21 then falls on a slide
out of the working range of the progressive tool and can, for
example, then be led sidewise out of the progressive tool in
accordance with FIG. 2, for example via a lateral slide under the
effect of gravity or with a burst of compressed air, etc.
[0033] The second hollow body element 21' falls through a hole 28
in the cut-off die 30 and subsequently through corresponding bores
32, 34, 36 and 38 which are formed in the plates 40, 42, 44 and
12.
[0034] The bores or the hole 38 in the plate 12 can lead with a
further bore (not shown) in the press table or in any intermediate
plate that is provided between the plate 12 and the press table
which enables the nut elements such as 21' to be led out, for
example under the action of gravity or also via a lateral slide or
using a burst of compressed air.
[0035] In the specific construction shown in FIG. 3, the plate 44
is screwed via non-illustrated screws to the plate 12. The plate 42
consists of a plurality of plate sections which are associated with
the respective working stations and which are screwed via further
non-illustrated screws (because they are arranged outside of the
plane of the sectional representation) to the through-going plate
44. The through-going plate 40 is likewise screwed to the sections
of the plate 42, and indeed also here by means of non-illustrated
screws. Above the through-going plate 40, there are in turn plate
sections 50, 52, 54, 56, 58 and 60 which are in turn screwed to the
plate 40. The plate 50 is a support plate which forms a lower guide
for the section 1, stated more precisely for the first broad side 2
of the section 1 which, in this representation, forms the lower
side. The plate sections 52, 54 and 56 are associated with the
working stations A, B and C, whereas the plate sections 58 and 60,
which form a receiver for the cut-off die 30, are associated with
the working station D.
[0036] Powerful compression coil springs 62 of which only the one
spring can be seen in FIGS. 2 and 3, because the others are located
outside of the section plane, are located at a plurality of
positions between the through-going plate 44 and the plate sections
50, 52, 54, 56, 58 and 60. These springs such as 62 have the
function of lifting the plate sections 50 to 60 on the opening of
the press, whereby the strip of section 1 is also lifted and hereby
moves out of the working range of the upsetting punches 64, 66,
whereby the section can be further advanced by twice the amount of
the length L of the hollow body elements 21.
[0037] The partition plane of the progressive tool is located above
the section 1 and is designated with T in FIG. 3.
[0038] Above the strip of the section, there are in turn located
plate sections 72, 74, 76, 78 and 80 which are screwed to a
through-going plate 82--also here via non-illustrated screws.
Furthermore, the plate 82 is screwed to the upper plate 16.
[0039] On the opening of the press, the plates 72, 74, 76, 78 and
80 are thus lifted with the plate 22 and the upper plate 16, and
indeed so far that the two hole punches 84, 86 and the two upper
flattening punches 88 and 90 as well as the dies 92 and 94, which
cooperate with the upsetting punches 64, 66, and also the cut-off
punch 22 move out of engagement with the strip of the section 1.
Through this movement, coupled with the lifting of the strip of the
section by the spring 62, it is made possible for the strip of the
section 1 to be able to be further advanced by twice the length
dimension of the hollow body elements 21 in preparation for the
next stroke of the press.
[0040] One sees that the working stations A and B have a
longitudinal dimension, i.e. in the direction 20 of the strip of
the section 1 which corresponds to four times the length dimension
of the hollow body element 21. The working station C has a length
dimension which corresponds to three times the length dimension of
the hollow body element 21 whereas the working station D has a
length dimension which corresponds to a multiple of the length
dimension of the hollow body element 21, in this example six times
as much.
[0041] This signifies that so-called empty positions such as 98 are
present at which no processing of the strip of the section 1 takes
place. These empty positions, however, provide space which is
necessary in order to be able to make the individual components of
the tools that are used sufficiently stable and to support
them.
[0042] Furthermore, one can see from FIG. 3 that the piercing dies
100, 102, which cooperate with the piercing punches 84, 86 have a
central bore 104 and 106 respectively, which are aligned with
further bores 108, 110 in insert sleeves 112, 114 which enable the
punched out slugs 116, 118 to be removed. These namely fall
downwardly through the bores 108, 114 which are larger in diameter
than the bores 104, 106 and through the further bores 120, 122 in
the plate 12 and can be disposed off or led away via corresponding
passages in the press table or in an intermediate plate which may
be provided in the same way of means as the nut elements 21.
[0043] Although not shown here, guide elements are located to the
left and right of the strip of the section 1, i.e. behind the plane
of the drawing and in front of the plane of the drawing of FIG. 3
and can for example be formed by cheeks of the plates 50, 52, 54,
56 and 58, which ensure that the strip of the section follows the
desired path of movement through the progressive tool. A small
lateral free space can be provided which permits any expansion of
the strip of the section which may occur in the transverse
direction.
[0044] The design details of the upsetting punches 64, 66 of the
die buttons 92, 94 which cooperate with them, of the hole punches
84, 86, of the die buttons 100, 102 which cooperate with them and
of the flattening punch 88, 90 can be seen from the drawings of
FIGS. 2 and 3 and will in other respects be explained more
precisely in the following drawings.
[0045] By means of the progressive tools of FIGS. 2 and 3 a method
is realized for the manufacture of hollow body elements such as nut
elements for attachment to components which usually consist of
sheet metal. The method serves for the manufacture of hollow body
elements 21, 21', for example with an at least substantially square
or rectangular outline by cutting individual elements to length
from a section 1 present in the form of a sectional bar or of a
coil after the prior punching of holes 23 into the section 1,
optionally with subsequent formation of a thread cylinder using a
progressive tool with a plurality of working stations A, B, C, D in
which respective operations are carried out. The method is
characterized in that in each case two operations are
simultaneously carried out for each stroke of the progressive tool
in each working station A, B, C, D for the section 1 or for a
plurality of sections arranged alongside one another. I.e. it is
basically possible to process a plurality of sections 1 alongside
one another and at the same time in the same progressive tool,
assuming that the corresponding number of individual tools such as
upsetting punches, hole punches and associated die buttons is
present.
[0046] In the last working station, two hollow body elements 21,
21' are in each case cut from the section or from each section 1 by
means of a cut-off punch 22.
[0047] The cut-off punch 22 cuts through the section at a first
point behind a first hollow body element 21 and at a second point
behind a second hollow body element 21', with the second hollow
body element 21' being guided out of the path of movement of the
section in the direction of movement of the cut-off punch
transversely to the longitudinal direction of the section 1. The
first hollow body element 21 is led out at least initially in
general in the direction of the path of movement of the section in
the cut-off station of the progressive tool.
[0048] Each working station of the progressive tool has a length in
the longitudinal direction of the section which corresponds to
three times or four times or the multiple of the longitudinal
dimension of a finished hollow body element 21, 21'.
[0049] In the embodiment of the progressive tool shown, a spring
loaded cam 27 having a cam surface 24 set obliquely to the path of
movement of the section is biased by the front edge of the front
end of the section at the outlet end of the last working station
against the force of the spring device 26. After cutting off the
hollow body element 21 formed at the front end of the section it is
tilted downwardly by the spring-loaded cam in order to facilitate
the removal from the progressive tool.
[0050] In the embodiment of FIGS. 2 and 3, the lower stamps 64, 66
operate to carry out the upsetting process and the hole punches 84,
86 to carry out the piercing process from opposite sides of the
section 1 on the latter. When carrying out the flattening process,
the respective flattening stamps 88, 90 act from above on the strip
of the section 1 while the strip is supported in the region of a
piercing by a plate section 56. Instead of this, it would also be
possible to arrange support pins at the plate section 56 at the
points of the holes in the strip of the section if it appears
necessary to support the section material in this region during the
flattening process, for example in order to achieve a more sharp
edged design of the end face of the hollow piercing section.
[0051] Some examples will now be given which describe the
manufacture of the specific hollow body elements.
[0052] Referring to FIGS. 4A-4E and FIGS. 5A-5D, the method of the
invention for the manufacture of hollow body elements such as nut
elements will now be described which are designed for application
to components which normally consist of sheet metal. One is
concerned here in particular with a method for the manufacture of
hollow body elements 200 having an at least substantially square or
rectangular outline 202 by cutting individual elements to length
from a section present in the form of a sectional bar (1, FIG. 1)
or a coil after the prior stamping of apertures 204 in the section,
optionally with subsequent formation of a thread cylinder 206 using
a progressive tool (FIG. 2, FIG. 3) having a plurality of working
stations A, B, C and D, in which respective operations are carried
out. The method is characterized by the following steps: [0053] a)
In a first step, starting from section 1, FIG. 4A which is
rectangular in cross-section, an upsetting process is carried out
using upsetting die buttons 92, 94 which come from the top and the
setting punches 64, 66. The upsetting process leads to a
cylindrical recess 208 at a first broad side 2 of the section 1 and
to a hollow cylindrical projection 210 at a second broad side 3 of
the section lying opposite to the first broad side 2, with the
projection being surrounded by a ring-like recess 212 which is
shown in FIG. 4B. The strip of the profile 1 is pressed during
closing of the press or of the progressive tool onto the ends of
the upsetting punches 64 and 66 projecting above the plate section
52. The projecting ends of the upsetting punches have a shape
complementary to the shape of the cylindrical recess 208 which is
shown in FIG. 4B. In similar manner, the end faces of the die
buttons 92, 94 cooperating with the upsetting punches have a shape
complementary to that of the hollow cylindrical projection 210 and
to the ring recess 212 surrounding it in accordance with FIG. 4B.
[0054] b) In a second step, a web 218 which remains between the
base 214 of the cylindrical recess 208 and the base 216 of the
hollow cylindrical projection 210 is pierced on the closing of the
press or of the progressive tool 10 by means of the hole punch 88,
90 to form the through-going aperture 204 (FIG. 4C). The
punched-out slugs are disposed of as mentioned via the bores 104,
106 and 108, 110 respectively. [0055] c) In a third step, the
hollow cylindrical projection 210 is flattened at its free end face
220 to form a piercing section 222 undercut on the outer side,
whereby the end face 224 in FIG. 4D is formed which stands in a
plane parallel to the broad sides 2 and 3 and perpendicular to the
central longitudinal axis 226 of the aperture 204. Thereafter, the
hollow body elements can be separated from the section in the
working station D and subsequently be provided with a thread 206 if
required, as shown in FIG. 4E or in the identical FIG. 5C.
[0056] The third step could, if required, be combined with the step
b).
[0057] During the upsetting process of the step a), the diameter of
the cylindrical recess and the inner diameter of the hollow
cylindrical projection are made at least substantially the
same.
[0058] Furthermore, the opening 229 of the cylindrical recess 208
at the first broad side 2 of the section is provided with a rounded
or chamfered run-in edge 230 which forms the thread run-out when
using the element, preferably during the upsetting process of step
a) or during the piercing process of step b) or during the
flattening process of step c).
[0059] During the upsetting process of step a) or during the
piercing process of step b) or during the flattening process of
step c), the mouth 232 of the hollow cylindrical projection 210 is
preferably also provided with a rounded or chamfered run-out edge
234 which forms the thread run-in in the finished element.
[0060] During the piercing of the web in accordance with step b,)
the aperture 204 is produced with a diameter which at least
substantially corresponds to the diameter of the cylindrical recess
208 and to the inner diameter of the hollow cylindrical projection
210. Furthermore, during the upsetting process of the first step
a), the free end of the hollow cylindrical projection 210 is
provided at the outside with a chamfer 236. Moreover, during this
upsetting process, the ring recess 212 is provided with a ring-like
base region 238 which stands at least approximately in a plane
parallel to the first and second broad sides 2, 3 of the strip of
the section and merges at the radially inner side with an at least
substantially rounded transition 240 into the outer side of the
hollow cylindrical projection 210 and merges at the radially outer
side into a conical surface 242 which forms an included cone angle
in the range between 60 to 120.degree., preferably of about
90.degree..
[0061] The transition 243 from the ring-like region 238 of the ring
recess 212 into the conical surface 242 is rounded as is also the
run-out 245 of the conical surface of the ring recess 212 into the
second broad side 3 of the section. The conical surface 242 can
present itself in practice such that the rounded transition 243
merges tangentially into the rounded run-out 245.
[0062] During the manufacture of the undercut 244, the latter is
formed by a cylindrical part of the hollow cylindrical projection
210 which merges approximately at the level of the second broad
side 3 of the section 1 into a region 246 of the hollow cylindrical
projection 210 which is thickened during the carrying out of the
step c) and which at least substantially projects beyond the second
broad side 3 of the section.
[0063] The thickened region 246 of the hollow cylindrical
projection 210 is made at least substantially conical and diverges
away from the first and second broad sides, with the cone angle of
the thickened region of the hollow cylindrical projection adjacent
to the end face 224 lying in the range between 30.degree. and
70.degree., preferably at about 50.degree.. After the flattening
process, the hollow cylindrical projection 219 terminates at its
free end at the outside in a piercing edge 250 which is made as
sharp edged as possible.
[0064] As can be seen from FIGS. 5A and 5B in particular, the ring
recess is executed with an outer diameter which is only somewhat
smaller than the smallest transverse dimension of the hollow body
element which is rectangular in plan view, whereby the ring recess
212 forms with the second broad side 3 at the section 1 webs 284,
286 in the range from 0.25 to 1 mm, preferably of about 0.5 mm
which remain at the narrowest points in the plane of the second
broad side 3.
[0065] The FIGS. 5E-5I and 5J-5N show essentially the same elements
as in the FIGS. 5A-5D but with small differences with respect to
the design of the piercing section 222 which has an ideal shape in
the two versions according to FIGS. 5E-5I and 5J-5N.
[0066] In the FIGS. 5E-5I and 5J-5N the same reference numerals
have been used which were also used in conjunction with the
previous embodiments. It will be understood that the previous
description also applies to the FIGS. 5E-5I and 5J-5N, i.e. that
the previous description of features with the same reference
numerals also applies to the description of the FIGS. 5E-5I and
5J-5N. This convention is also retained in the further Figures so
that only important differences or significant features will be
especially described here.
[0067] The main difference between the embodiments of FIGS. 5E-5I
and the embodiment of FIGS. 5J-5N lies in the fact that the
embodiment of FIGS. 5E-5I is used for thicker sheet metal in the
range of, for example, 1.2 to 2.0 mm sheet metal thickness whereas
the embodiment of FIGS. 5J-5N is used for somewhat thinner sheet
metal, for example in the range of 0.4 to 1.2 mm sheet metal
thickness.
[0068] Specifically, FIG. 5E shows a view from below onto the lower
end face of the piercing section 222, i.e. in the arrow direction E
of FIG. 5H. The FIG. 5F is a sectional drawing corresponding to the
vertical section plane F-F in FIG. 5E, so that in FIG. 5F the two
ribs 272 providing security against rotation which extend in the
axial direction and which are located at the 12 o'clock and the 6
o'clock positions in FIG. 5E can each be seen in section. In
contrast four further ribs 272' providing security against rotation
which are entered into FIG. 5E can be seen neither in FIG. 5F nor
in FIG. 5G which shows a section drawing in accordance with the
section plane G-G. They can also only be recognized by way of
indication in FIG. 5E because they are in principle largely hidden
behind the piercing section 222. They are not evident in the
sectional drawing of FIG. 5 because the section plane is selected
such that the ribs 272 or 272' providing security against rotation
do not lie in the plan of the section or adjacent the plane of the
section and are also not sufficiently large that they could be
recognized in side view on the section plane.
[0069] The FIGS. 5H and 5I each show an enlarged representation of
the regions shown in a chain-dotted rectangle in FIG. 5G or 5F
respectively. It can be seen from FIG. 5H to 5I that the lower end
face 224 of the piercing section 222 is formed by a radius in the
section plane which runs out tangentially at the cutting edge
250.
[0070] This represents a distinction to the end face 224 of the
embodiment of FIGS. 5A-5D which has a significant ring surface
component in a plan perpendicular to the central longitudinal axis
226 of the hollow body element.
[0071] Furthermore it can in particular be recognized from the
drawings of FIGS. 5H and 5I that the region of the ring recess 212
designated as a conical inclined surface 242 in FIG. 5D is actually
formed by two radii which merge into one another at a turning
point. In this example, with only a very short straight portion
which is indicated by the two lines 301 and 303 and which in
practice also does not have to be present, i.e. the two radii which
form the obliquely set wall of the recess (curved regions 243 and
245) can merge directly into one another tangentially.
Nevertheless, in the region of the turning point a surface region
is present which can be termed approximately flat so that the
designation "at least substantially conical" is justified.
Naturally, a clearer strictly conical region could also be
provided.
[0072] Through the use of the same reference numerals it can be
seen that the FIGS. 5J-5N are to be understood in precisely the
same way as the FIGS. 5E-5I. The only difference here is that the
noses 272' providing security against rotation in FIG. 5E cannot be
seen in FIG. 5J, and indeed because they are actually hidden behind
the ring-like piercing edge 250. Thus, the noses 272 providing
security against rotation can only be seen in FIG. 5K and in FIG.
5N.
[0073] In an alternative method which leads to the hollow body
element in accordance with FIGS. 6A to 6E, a ring-like raised
portion 260 is formed around the cylindrical recess 208 during the
upsetting process in accordance with step a) by the use of
correspondingly shaped upsetting punches 64, 66 and upsetting die
buttons 92, 94 at the first broad side 2 of the section, which for
example essentially represent a material volume which corresponds
to the volume of the ring recess 212 around the hollow cylindrical
projection. In this embodiment, the diameter of the cylindrical
recess 208 is larger than the internal diameter of the hollow
cylindrical projection 210. Furthermore the thread 206 terminates
in a conical region 262 of a stepped hole 264 which, in this
example, can be optionally used instead of a rounded thread run-out
(which would also be possible in the embodiment of FIGS. 4A to 4C
or FIGS. 5A to 5D respectively).
[0074] The base of the ring recess is, in this embodiment, formed
solely by a rounded transition 243 from the hollow cylindrical
projection 210 into the conical surface 242, which would also be
possible in the embodiment of FIGS. 4A to 4E and FIGS. 5A to 5D
respectively.
[0075] During the upsetting process in accordance with step a),
features 272 providing security against rotation are formed by
corresponding profiling of the upsetting punches 9, 94 outwardly at
the hollow cylindrical projection 210 and internally in the region
of the ring recess 212 around the hollow cylindrical projection
210.
[0076] These features providing security against rotation can (as
shown) be formed by ribs 272 and/or by grooves (not shown) at the
radially outer side of the hollow cylindrical projection 210. These
ribs 272 extend in the axial direction 226 and bridge the undercut
244 of the hollow cylindrical projection 210. They have a radial
width which corresponds at least substantially to an amount in the
range between 40% and 90% of the maximal radial depth of the
undercut.
[0077] Thus, a hollow body element 200 arises for attachment to a
component 280 which normally consists of sheet metal (FIGS. 7A and
7B respectively) with an at least substantially square or
rectangular outline 202 with a first broad side 2 and a second
broad side 3 and with a piercing section 246 which projects beyond
the second broad side and has an undercut and is surrounded by a
ring recess 212 in the second broad side as well as with an
aperture 204 which extends from the first broad side 2 through the
piercing section 246, with the aperture optionally having a thread
cylinder 206 and with the hollow body element being characterized
in that features 272 providing security against rotation are formed
outwardly on the hollow cylindrical projection 210 and/or inwardly
in the region of the ring recess 212 around the hollow cylindrical
projection 210.
[0078] The hollow body element is further characterized in that the
second broad side 3 lies radially outside of the ring recess 212 in
one plane, i.e. apart from any rounded features or chamfers at the
transitions into the side flanks of the hollow body element and
thus no bars, grooves or undercuts are present in the region
outside of the ring recess.
[0079] The ring recess 212 is executed with an outer diameter which
is only slightly smaller than the smallest transverse dimension of
the hollow body element rectangular in cross-section in plan view,
whereby the ring recess forms webs in the range from 0.25 to 1 mm
and preferably of about 0.5 mm with the second broad side 3 of the
section which remain at the narrowest points 284, 286 in the plane
of the second broad side.
[0080] The FIGS. 7A and 7B show how one and the same elements 200
in accordance with the invention can be used in accordance with
FIGS. 5A to 5D with a thinner sheet metal part (FIG. 7A) of, for
example, 0.7 mm thickness and with a thicker sheet metal part (FIG.
7B) of for example 1.85 mm thickness. The sheet metal material
fills out the entire ring recess 212 after the pressing by means of
a die button and lies in contact with the full surface of the ring
recess and of the features 272 providing security against rotation
in the region of the undercut. Thus, in both cases, a good overlap
with the ribs 272 providing security against rotation takes place
and thus a good security against rotation between the hollow body
element 200 and the sheet metal part 280. The piercing section 246
is at least not essentially deformed in these examples and is
introduced in self-piercing manner into the sheet metal part. The
flattened end face 224 of the piercing section 246 lies with thin
metal sheets (as shown in FIG. 7A) at the level of the lower side
of the sheet metal part and with thicker sheet metal parts (FIG.
7B) above the lower side of the sheet metal part (i.e. the side of
the sheet metal part remote from the body part of the hollow body
element). In both cases, a ring recess 282 is present around the
piercing section which has a form given by the specific shape of
the complementary designed die button during the self-piercing
attachment of the hollow body element in a press or through a robot
or in a C-frame. In this connection, the die button has, as is
usual in the self-piercing attachment of fastener elements, a
central bore through which the punched-out slugs which arise are
disposed of. Although the hollow body elements in accordance with
the invention are made self-piercing, they can nevertheless be used
in pre-pierced sheet metal parts. In a second embodiment of the
hollow body element in accordance with the invention, a further
range of thicknesses of sheet metal parts can be covered, for
example 1.85 to 3 mm. It is simply necessary to make the piercing
section somewhat longer.
[0081] As the hollow body elements which are square in plan view
are attached in such a way that the second broad side 3 directly
contacts the upper side of the sheet metal part 280, but does not
or essentially does not dig into the sheet metal part, a notch
action need not be feared so that a good fatigue behavior results
thanks to a good fatigue resistance even under dynamic loads.
Although the hollow body elements are square in plan view no
special orientation of the die button relative to the respectively
used setting head is necessary because the piercing section is
circular in plan view and thus orientation-free. It is only
necessary to ensure that the setting head and the die button lie
coaxial to one another and to the longitudinal axis 226 of the
hollow body element. During attachment of a further component to a
component assembly in accordance with FIG. 7A or 7B, the further
component is normally secured to the sheet metal part at the bottom
by a screw (not shown) which is screwed, coming from the bottom
into the thread. In this way, the connection between the hollow
body element 200 and the sheet metal part is increased through
tightening of the screw.
[0082] Furthermore it should be pointed out that ribs providing
security against rotation would be conceivable which cross or
bridge the ring recess 212 in the radial direction as for example
shown in FIGS. 8A-8D, FIGS. 9A-9D or FIGS. 10A-10D. Such ribs
providing security against rotation could lie flush with the broad
side 3 (FIGS. 8A-8D) or could be present recessed with the ring
recess (such features providing security against rotation are not
shown in the drawings).
[0083] In the embodiment of FIGS. 8A-8D the free top sides of the
ribs providing security against rotation, which are indicated with
272'' lie in the same plane as the surface of the broad side 3
outside of the ring recess 272. The sides 272'' can, however, also
be arranged set back from the broad side 3. Since the ribs
providing security against rotation bridge the ring recess 212,
they are also to be found at the side of the ring-like piercing
section 222 in the region of the under-cut 244.
[0084] The FIGS. 9A-9C show a further variant in which the features
providing security against rotation have the shape of ribs
providing security against rotation which extend in the radial
direction over the ring recess 212, but the upper sides 272''' of
the ribs 272 providing security against rotation of the embodiment
in accordance with FIGS. 9A-9D are set obliquely so that they rise
going in the direction towards the piercing section 222 and thus
not only extend in the radial direction over the ring recess and
bridge it, but rather also extend in the axial direction at the
under-cut 244 of the piercing section 222 over a considerable
length or over the full length in the undercut 244.
[0085] The FIGS. 10A-10D shown an embodiment which is very similar
to that of the FIGS. 9A-9D, but here the ribs providing security
against rotation are angled so that they have a radial component
272'''' and an axial component 272''''' which merge into one
another via a radius 272'''''' and thus generally have the
described angled shape.
[0086] FIGS. 11A-11D show another kind of features providing
security against rotation, here in the form of recess 272''''''' or
grooves which are formed in the obliquely set side wall of the ring
recess 212, with the recesses 272''''''' having an approximately
shell-like shape in plan view here. Other shapes of the recesses
are also conceivable, for example elongated grooves which are made
narrower in the region of the broad side 3.
[0087] Finally, the FIGS. 12A-12D show a somewhat different form of
a hollow body element in accordance with the invention.
[0088] The important distinction in the shape of the hollow body
element in the embodiment in accordance with FIGS. 12A-12D is to be
seen in the fact that the ring recess has a polygonal shape 212'
here, and indeed in the specific case a square shape in plan view,
with the ring recess having a corresponding number, i.e. four, of
inclined surfaces 400, 402, 404 and 406 which merge into one
another by means of radii 408, 410, 412 and 414. At the lowest
point of the ring recess 212' which is polygonal in plan view there
is an areal region which is defined by four corner regions 416,
418, 420 and 422 and is arranged in a plane perpendicular to the
central longitudinal axis 226 of the element. The piercing section
222 merges via a radius 424 into these corner regions, with the
radius having a diameter at the radially outermost point which is
fractionally larger than the maximal transverse dimension of the
areal region formed by the four corners 416, 418, 420 and 422 so
that this radius ultimately merges into the lowest side of the four
obliquely set surfaces. All thin parallel lines such as 426, 426'
and 426'' show radii or rounded surfaces which ensure amongst other
things a gentle bending of the sheet metal part.
[0089] In this embodiment, it is not necessary to provide separate
ribs providing security against rotation because the polygonal
shape of the ring recess 212' itself takes care of the required
security against rotation. This embodiment is also advantageous
because the obliquely set surfaces and also the corner regions in
the base region of the ring recess belong to the contact surface of
the element so that it is possible to operate with correspondingly
low surface pressures at the sheet metal part and the danger of
settling of the element does not exist. Nevertheless, high values
for the security against rotation can be achieved as well as a high
pull-out resistance.
[0090] The rounded regions between the obliquely set surfaces also
have the advantage that no pronounced sharp features are present at
these points in the sheet metal part which could lead to fatigue in
particular with dynamic loading of the component. Because the
piercing section 222 produces a circular hole in the sheet metal
part, as in other embodiments, stress concentrations are also not
to be expected here which could lead to fatigue cracks in
operation. During the attachment of the hollow body element to the
sheet metal part, the element is at least substantially not
deformed, a deformation is undesired and the sheet metal part is
brought by a suitable complementary shape of the die button into
the square recess 212' in the region around the piercing section
222 and fully into contact with this piercing section around the
piercing section.
[0091] In all embodiments of FIGS. 8A-8D to FIGS. 12A-12D, the
hollow body element is made flat at the first broad side 2, i.e.
with an end face which lies perpendicular to the central
longitudinal axis 226 of the element in accordance with the
previous embodiment of FIGS. 5A-5N. It is, however, entirely
conceivable that the corresponding end face in the embodiments of
FIGS. 8A-8D to FIGS. 12A-12D could be made similar to the
embodiment of FIG. 6D. In the FIGS. 12A-12D this signifies that,
instead of a circular ring shape raised portion as in FIG. 6D, the
raised portion will then have a corresponding polygonal shape, here
a square shape.
[0092] When the talk in this application is of a polygonal shape
this also includes in any case polygons with three to twelve
polygonal surfaces i.e. obliquely set surfaces.
[0093] In the embodiment of FIGS. 12A-12D, a considerable material
displacement takes place in the region of the recess which is
square in plan view as shown so that it is here entirely possible
for the hollow cylindrical projection which is transformed by the
flattening into the piercing section 222 to be achieved solely by
material displacement from the second broad side 3 of the hollow
body element, i.e. it is not necessary to carry out an upsetting
process in the first step of the manufacturing method in which
material is displaced from a first broad side 2. I.e. the first
manufacturing step a) in accordance with claim 1 can be replaced
here by a forming process in which the hollow cylindrical
projection 210 is formed solely by material displacement out of the
region of the ring recess which is polygonal in plan view and in
the region of the hollow space of the hollow cylindrical projection
210. During the subsequent piercing process the body formed in this
way is then pierced starting from the first broad side 2 and up to
the base 216 of the hollow space 232.
[0094] Although the present invention is intended for the
manufacture of elements which are rectangular or square in outline,
it could also be used for the manufacture of elements which are
polygonal, oval or circularly round in outline or of elements with
another shape, provided the tools that are used are designed in
order to manufacture the desired shape of the outline from the
strip of the section, for example through the use of
correspondingly designed punching tools.
[0095] The design of the ring recess 212 does not necessarily have
to take place at the same time as the upsetting process, but could
rather be combined with the piercing process or with the flattening
process, i.e. the piercing punches 84, 86 or the flattening punches
88, 90 must in this case have a corresponding shape.
[0096] It is not necessary to separate the hollow body elements
from one another in the progressive tool, but rather the section
can be retained or used after manufacture of the general shape of
the hollow body elements in sections or in re-coiled shape, with a
separation into individual hollow body elements then only taking
place when the section is used in a setting head for the attachment
of the hollow body elements to a component.
[0097] In all embodiments, all materials can be named as an example
for the material of the section and of the functional elements
which are manufactured from it which, in the context of cold
deformation, reach the strength values of class 8 or higher in
accordance with the ISO standard, for example a 35B2 alloy in
accordance with DIN 1654. The fastener elements formed in this way
are suitable amongst other things for all normal steel materials
for drawing quality sheet metal parts and also for aluminum or its
alloys. Also aluminum alloys, in particular those of high strength,
can be used for the section or the functional elements, for example
AlMg5. Sections or functional elements of higher strength magnesium
alloys such as for example AM50 also enter into consideration.
* * * * *