Note: Descriptions are shown in the official language in which they were submitted.
~ CA 02214730 1997-09-0~
AUon~ey No. 60,174-005
PRESS FORM ELEMENT, METHOD OF INSTALLATION AND ASSEMBLY
FIELD OF THE INVENTION
The present invention relates to a method for the sealed attachment, in particular
for the liquid-tight and/or gas-tight attachment of a functional element, in particular of a
functional element having a head part and a functional part, to a sheet metal part in which
the element does not penetrate through the sheet material but is secured to the sheet metal
part for the tr~n~mi.c.~ion of axial forces and preferably also of torques. Furthermore, the
present invention relates to a functional element, to a component assembly comprising the
functional element and a sheet metal part, and also to a die button and to a setting head
for use in the method of attaching a functional element to the sheet metal part.
RELATED APPLICATIONS
This application is a continuation-in-part application of U.S. Serial No. 698,870
filed August 16, 1996 which claims priority to German Application Serial No.
19530466.7 filed August 18, 1995. Further, this application claims priority to German
Application No. 19647831.6 filed November 19, 1996.
DESCRIPTION OF PRIOR ART
In the construction of vehicle bodies in particular, but not exclusively, the need
frequently exists to provide an absolutely liquid-tight and preferably also gas-tight connec-
tion between a sheet metal part and a functional element having a shaft part and a head
part. As used herein, a functional element is a device which, following attachment to a
sheet metal part or panel as disclosed herein, is designed to perform a function, such as a
male or female fastener, which may be used to attach another element or part to the sheet
metal part. By way of example, pegs can be provided in the floor region of a vehicle and
represent functional elements to which carpets are to be secured. Water, for example,
coming in from the road, must in any event be prevented from rising upwardly through
capillary gaps created as a result of the perforation of the sheet metal floor during the
attachment of the functional element, and thus leading to corrosion of the sheet metal
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floor, or of the functional element, or the carpet suffering damage due to rising moisture.
It is indeed possible, with very accurate process control, to make a liquid-tight
and/or gas-tight connection with bare sheet metal parts or sheet metal parts with metallic
coatings, using already known piercing and riveting bolts. However, the mass production
of products at reasonable cost is not possible in this way, in particular when the tools
wear during long manufacturing series and when the sheet metal parts are subject to
tolerances.
The liquid-tight and/or gas tight attachment of fastening elements to sheet metal
parts which are coated on one or both sides with plastic, with foils and/or with paint coat-
ings, represents a particular difficulty because the coating is frequently damaged during
the insertion process, and capillary gaps are thereby created. Moreover, a loosening of
the connection can be expected during subsequent thermal treatments, for example during
the application of paint in a heated chamber, and can also lead to unexpected capillary
gaps.
A connection which is absolutely liquid-tight and/or gas-tight can presently
actually only be ensured with so-called welded elements, which are butt-welded onto the
sheet metal surface. The use of functional elements which can be welded on is, however,
not straightforwardly reconcilable with modern methods during sheet metal processing
because it disturbs the course of the sheet metal processing, which largely takes place in
presses, i.e. it represents a foreign step. The heat generated during welding is also in
many cases disruptive because it can lead to a local reduction of the characteristics of the
sheet metal part. With coated sheet metals the use of a welding process is particularly
difficult because the coating is locally damaged by the heat-intensive welding process. For
sheet metal parts which are provided with plastic and/or foil and/or paint coatings, it is,
moreover, difficult to always ensure a good electrical connection between the sheet metal
part and the element during butt-welding. When this is achieved, then gases which are
also partly poisonous are liberated as a result of the process heat.
It is in some cases also important to connect functional elements in the form ofhollow body elements with a hollow body part, for example in the form of a nut element,
to a sheet metal part, without a gas or a liquid being able to pass through the sheet metal
part into the hollow element. For example, such requirements likewise arise during the
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construction of vehicle bodies or the manufacture of injection-molded parts with inserts in
the form of sheet metal parts equipped with nut elements, where the injection molding
composition is not allowed to penetrate through the sheet metal part into the thread.
OBJECT OF THE INVENTION
The object of the invention is to make available a method and/or a functional
element and a component assembly in which a connection which is at least substantially
always liquid-tight and preferably also gas-tight is ensured between the functional element
and the sheet metal part with a procedure which involves little heat and indeed without
any eventually present coating of the sheet metal part being so damaged that thefunctionality of the desired appearance of the component assembly is no longer present.
Furthermore, the method should be capable of being achieved without special complexity
during the mass manufacture of sheet metal parts using favorably priced tools and over
long production series.
BRIEF DESCRIPTION OF THE INVENTION
In order to satisfy this object, provision is made for the element to be connected to
the sheet metal part by a shape-giving joining process, with the procedure preferably
being such that the sheet metal part is connected in form-fitted manner to the head part,
or in the case of using a hollow element, to the body of the hollow element, without
perforating the sheet metal part, by the action of force between a setting head which
guides the functional element and is arranged on one side of the sheet metal part and a
die-button arranged on the other side of the sheet metal part.
Since the sheet metal part is not perforated during the attachment of the functional
element, the sheet metal part is so to say preserved as a closed membrane so that no
capillary gaps can arise between the two sides of the sheet metal part. It is admittedly not
straightforwardly possible in this manner to produce a connection between the functional
element and the sheet metal part which has the same resistance to pulling out of the
functional element as a connection in which the head part of the element is arranged on
the other side of the sheet metal from the shaft part. One can, however, certainly achieve
an adequate strength of the connection, which is fully sufficient in many of the
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applications which exist and in which the maximum strength of the connection is not
required, for example for the attachment of carpets in vehicles, for the mounting of
headlinings in vehicles or during installation of brake lines, cables, lamps and the like.
So-called throughjoining processes and punch-riveting processes are admittedly
known which do not, as a rule, lead to perforation of the sheet metal part. In the through-
joining method, two sheet metal parts are secured to one another in known manner, with
the two sheet metal parts being deformed in such a way that they are hooked intoengagement within each other in a form-fitted manner. However, no functional element
and also no auxiliary element is used here. During punch-riveting, an auxiliary element in
the form of a punch rivet is admittedly used for the connection of two sheet metal parts,
the punch rivet does not, however, represent a functional element and has no form of
shaft or functional part. Moreover, modified versions of punch rivets are admittedly
known which are connected to a shaft part and which are intended for insertion into only
one sheet metal part. With these punch rivets a perforation of the sheet metal part via the
punch rivet is not necessarily intended, but however occurs in some cases when consid-
ered statistically, so that this known method also does not make it possible to achieve a
liquid-tight and/or gas-tight mounting, which is suitable for mass production.
With the method of the invention several possibilities exist of achieving the form
fitted connection between the sheet metal part and the head or body part of the functional
element. For example, to produce the form-locked connection, the head part or the body
part is formed with an open hollow cavity at its end face facing the sheet metal part, with
the hollow cavity having at least one undercut feature, and the sheet material is hooked
into engagement with this undercut feature by means of the die button.
The formation of such undercuts in a hollow cavity is, for example, described inthe above-referenced copending U.S. patent application Serial No. 698,870 in connection
with nut elements. In the method described in the U.S. application, the sheet metal part is
pierced during the attachment of the nut element by a preceding hole punch so that the
connection is not watertight. Nevertheless, the method disclosed there can be
straightforwardly used with the subject of the present application for the formation of the
undercut features, and for the formation of the features providing security against
rotation, which is the reason why the content of this earlier copending U.S. patent
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application or of the corresponding German application 195 30 466.7 from which priority
is claimed is made part of the disclosure of the present application.
Another possibility for the formation of the form-locked connection between the
head part or body part of the functional element and the sheet metal part, which can be
used as an alternative to the above mentioned possibility, or also in addition to it, lies in
providing the head part at its outer periphery with at least one undercut feature, with
which the sheet material forms a hooked engagement. In this embodiment it is particularly
advantageous when the material of the head or body part of the functional element is
deformed by means of the setting head in order to generate or to improve the hooked
engagement.
The method in accordance with the invention, or the corresponding functional
element, is particularly well suited for use with coated sheet metal parts, and in particular
with sheet metal parts which are coated on one or both sides, for example with a metallic
coating and/or a plastic coating and/or a foil coating and/or a paint coating and in that the
shaping method is carried out by using rounded shaping edges both in the element and
also at the die.
During the processing of galvanized sheet metal parts, or using coated sheet metal
parts coated with zinc, the coating is also deformed during deformation of the sheet metal
part and is thus preserved even after the attachment of the functional element to the sheet
metal part. With plastic, foil or paint coatings, these can also be designed with modern
techniques in such a way that they are not damaged by the attachment method, or are
only damaged in regions which stand in close contact with the head part of the functional
element, and are not, or at least substantially not, visible or accessible from the outside.
Several possibilities exist for achieving the required security against rotation. For
example, features providing security against rotation can be provided in the hollow cavity
of the head or body part and/or at the ring wall and/or at the end face of the head or
body part confronting the sheet metal part and/or at the outer periphery of the head or
body part, optionally only in the lower region of the same. For this purpose the outer
periphery of the head or body part can have an oval, polygonal or grooved shape.
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The requirements which are placed on security against rotation are less criticalwith the functional elements which are being discussed here because they are frequently
attached to the complementary fastener elements not by rotation but rather by an axially
directed movement or by a snap connection.
For this reason it is frequently possible to eliminate, in cost saving manner,
features in the die button which would lead to a closed hooked engagement with the
features of the functional element providing security against rotation. For example, when
using features providing security against rotation in accordance with the above mentioned
copending U.S. patent application, the corresponding noses at the die button could be
omitted. Through the multi-cornered shape of the sheet material which is deformed into
the hollow cavity of the element, an adequate security against rotation is achieved with
the subject of the present application without the use of these noses. This also has the
advantage that the coated surface of the sheet metal part is also not damaged by the noses.
Further, special embodiments of the subject of the invention and also further
details on the underlying object can be taken from the following description of the
drawlngs.
BRIEF DESCRIPTION OF THE FIGURES
In the following embodiments of the invention will be explained in more detail
with reference to the accompanying drawings, in which are shown:
Fig. 1 a partially cross sectioned side view of a functional element of this invention,
Fig. lA a partial side view of an alternative fastening element for the functional
element at Fig. 1,
Fig. 2 a plan view of an end face of the functional element of Fig. 1 seen in the
direction of view arrow 2,
Fig. 3 a partial side partially cross-sectioned view similar to Fig. 1 of a modif1ed
embodiment of a functional element,
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Fig. 4 a plan end view in accordance with Fig. 2, but as seen in the direction of view
arrow 4 of Fig. 3,
Fig. S a side partially cross-sectioned view of the functional element which is ready
for installation, of Fig. 1,
Fig. 6 a side cross-sectional view showing the attachment of the functional element of
Fig. 5 to a sheet metal part using a setting head and a die button, with the
illustration being only partly sectioned and being only shown on one side of
the longitudinal axis of the functional element,
Fig. 7 a representation of a further embodiment of a functional element similar to
Fig. 6,
Fig. 8 a side partially cross-sectioned view of a representation in accordance with
Fig. 1, but of a further modified embodiment,
Fig. 9 a plan end view onto the end face of the head part of the functional element of
Fig. 8 as seen in the direction of the arrow 9,
Fig. 10 a partial side cross-sectional view illustrating a first working step during the
attachment of the functional element of Fig. 8 to a sheet metal part using a
setting head and a die button,
Fig. 11 a partial side cross-sectioned view illustrating a later phase of the method of
attachment which started in Fig. 10,
Fig. 12 a partial side cross-sectioned view illustrating the end phase of the method of
attachment of Figs. 10 and 11,
CA 02214730 1997-09-0~
~ig. 13 an enlarged representation of the region of Fig. 13 characterized by 13, with a
possible modification being shown, and
~igs. 14, 15, 16 and 17
drawings which correspond to those of Figs. 6, 7, 12 and 13, but using a
functional element in the form of a hollow element, wherein Figs. 16 and 17
is a further modified element.
DESCRIPTION OF PREFERRED EMBODIMENTS
In all Figures the corresponding reference numerals are used for same part or parts
which have the same function. Moreover, in all Figures in which only the right hand half
of the respective embodiment is shown it should be assumed that the left hand half is
designed with mirror-symmetry to the right hand half and is only being omitted for the
sake of the illustration.
Figs. 1 and 2 show, first of all, a functional element 10 with a shaft part 12 and a
head part 14. As can be seen from Fig. 1, the shaft part 12 is provided here with a thread
16. This is, however, required as is shown in Fig. lA, the shaft part 12 can, for
example, be realized simply as a cylindrical shaft 17A. The shaft part can be fashioned in
any desired manner, depending on the element with which the functional element 10 is to
cooperate.
The head part 14 of this element is of hollow shape, i.e. it has a hollow cavity 18
and it is formed in its lower region in Fig. 1 in accordance with the nut element of the
above-referenced copending U.S. patent application. I.e. undercut features 20 are formed
by wedge-like recesses arranged in the end face 22 of the head part 14 at regular intervals
around the central longitudinal axis 24, with the wedge-like recesses being produced by a
correspondingly shaped cold heading tool.
As can be seen from Figs. 1 and 2, these wedge-shaped recesses 26 have their
greatest depth at the entry into the hollow cavity 18 and merge in the middle region of the
circular end face 22 into this end face. The functional element thus has a circular contact
surface in the outer region of the end face 22. The material displaced by the wedge-like
recesses forms the noses 28, which define the narrowest part of the hollow cavity 18.
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In deviation from the nut element shown in the above-referenced copending U.S. patent
application, the head part of the functional element of Figs. 1 and 2 has, at the center of
the base surface of the hollow cavity 18, a ring wall 30 which projects from this base
surface, and which goes in the direction of the end face 22 of the head part, with the
length of the ring wall, however, being selected such that it terminates before it has
reached the narrowest point of the hollow cavity 18 formed by the noses 28. The ring
wall 30 has its own planar end face 32. This planar end face 32 merges via a chamfer 34
into a rounded recess 36 at the center of the ring wall 30. At the radially outer side, the
planar end face 32 of the ring wall 30 merges via a rounded edge 38 into the cylindrical
outer wall 40 of the ring wall.
As can likewise be seen from Fig. 1, the head part has at the end face 22 a
rounded peripheral edge 42 and likewise has a peripherally extending rounded edge 46 at
the end face 44 adjacent the shaft part 12.
As will be subsequently explained in more detail, the undercut features 20 enable
an form-fitted connection with the sheet metal part so that the functional element can only
be pulled out of the sheet metal part in the axial direction with the exertion of a high
force. The recesses 26 and also the regions 48 between the noses 28 form features
providing security against rotation, into which the sheet metal material is embedded.
Figs. 3 and 4 show an alternative design of the functional element of Figs. 1 and
2, in which, in deviation from the embodiment of Figs. 1 and 2, the noses 28 arereplaced by a peripherally extending ring nose 128 and the wedge-shaped recesses 26 are
replaced by a peripherally extending conical recess 126. Because the ring nose 28 and the
ring recess 26 are no longer able to serve as features providing security against rotation,
longitudinal grooves 150 are provided in the lower region of the outer periphery of the
head part 114 and ensure the security against rotation, as will likewise be explained later
in more detail.
The functional element of Figs. 3 and 4 is also formed as a cold headed part, with
the material driven out of the conical recess 126 being used to form the ring nose 128.
The Figs. 5 and 6 now show the attachment of the functional element lO of
Figures 1 and 2 to a sheet metal part 52.
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The sheet metal part 52, which is already shown in Fig. 6 in the form in which it
is in form-locked connection with the head part 14 of the functional element, had, before
the insertion of the functional element 10, the shape of a planar sheet metal panel, with
this however not being essential. For example, the sheet metal part 52 could represent a
region of a previously formed recess in the sheet metal part. It can be seen from Fig. 6
that the functional element 10 is guided by a setting head 54, which has a plunger 56
movable in the axial direction 24 and a tubular housing 57 around the latter which is
biased by springs 58.
The functional element 10 is, as is presently customary during sheet metal
processing, connected with the sheet metal part by means of a press and indeed by the
cooperation of the setting head 54 with the die button 60. In this respect the die button 60
is received in the lower tool of the press, while the setting head 54 is attached to the
upper tool of the press or to an intermediate plate of the press. Other possibilities of
attachment also exist. For example, the die button 60 can be attached to the intermediate
plate of the press, and the setting head 54 can be attached to the upper tool of the press,
or inverse arrangements are conceivable in which the die button 60 is mounted in the
upper tool of the press, and the setting head 54 in the lower tool of the press or on the
intermediate plate. The use of a press is also not absolutely essential. By way of example
arrangements are known in which the die button and the setting head are carried by a
robot, and the required relative movement between the setting head 54 and the die button
60 in the direction of the axis 24 is achieved either by the robot itself or by the action of
force from the outside.
The arrangement is so arranged that at the start of the closing movement of the
press, the resiliently biased housing part 57 first clamps the sheet metal part 52 between
its end face 62 and the end face 64 of the die button. The sheet metal part 52 can now no
longer slip in the tool. During the further closing movement of the press, the end face 66
of the plunger 56 now contacts the end face 44 of the functional element 10 and presses
the other side 22 of the head part 14 opposite to the shaft part against the sheet metal part
52, which is pressed by the closing force of the press into the ring recess 68 of the die
button, with a pot-like recess or cavity 70 being formed in the sheet metal part 52 with
simultaneous stretching of the same.
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In the central region the die button 60 has a cylindrical projection 72 with a
cylindrical outer wall 74 and a conical end face 76, which merges via a rounded ring
recess 78 into a rounded ring nose 80. During the closing of the tool, the end face 76 of
the die button 60 deforms the sheet metal material into the hollow cavity 18 of the head
part 14 and pushes the material partly into the undercuts 20 formed by the noses 28.
During the closing phase, the conical, upwardly rounded end face 76 of the cylindrical
projection 72 displaces the sheet metal in the radially outward direction and
simultaneously deforms the ring wall 30 via the sheet material in such a way that the
spreading movement of the ring wall 30, which takes place radially outwardly, likewise
pushes material into the undercuts 20.
Fig. 6 shows the state after the conclusion of the setting process and it is clearly
evident that a form fitted connection has taken place between the sheet metal part and the
functional element 10 in the region of the undercuts 20. As a result of the closing
movement of the tool, the sheet metal material has, however, also been drawn into the
recesses 26 so that a hooked engagement also takes place here and the required security
against rotation is also achieved. The sheet material is, however, also pressed into the
regions 48 between the noses 28 which cannot be seen from this drawing so that security
against rotation also arises here. It is particularly important that the sheet metal part 52
has not been punctured at any point by the head part of the functional element 10. I.e. the
sheet metal part 52 forms a continuous membrane which takes care of the absolute sealing
which is required.
It can also be seen from Fig. 6 that all shaping edges of the die button, for
example at the transition 82 between the planar end face 64 and the here cylindrical inner
peripheral wall 84 of the recess 68 of the die button and at the transition 86 between the
vertical wall 84 of the recess of the die button and the horizontal planar base surface 88
of the recess 68 and also in the region of the ring nose 80 of the recess 78 and of the tip
of the conical end face of the cylindrical projection 72 are rounded. The transition
between the base surface 88 of the recess 68 and the cylindrical side wall of the cylin-
drical projection 72 admittedly need not be rounded, but is, however, normally rounded
for reasons of strength. One notes that in the region of this transition a free space 90
exists after the connection has been carried out. A further free space 92 can be seen
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adjacent to the deformed ring wall. These free spaces are desired because they can be
filled to a greater or lesser degree, depending on the sheet metal tolerances and the
flowability of the sheet metal material without damage to the tools, which would have to
be feared with complete filling of these spaces.
The rounded transitions 42 of the lower end face of the functional element, in the
region of the noses 28, and at the transition from the undercuts 20 into the base surface of
the hollow cavity 18, and also at the edges of the ring wall 30, are also formed as
rounded forming surfaces. In this manner one avoids an injury of the sheet metal part 52,
which could eventually lead to perforation of the latter.
After the connection in accordance with Fig. 6 has been completed, the sheet
metal part 52 not only has a pot-like recess 70, into which the head part 14 and the
functional element 10 is partly received, but rather an inverse pot-like shape in the center
of the base region of this pot, where the sheet metal material was pressed into the hollow
cavity 18 of the head part.
Fig. 7 shows that the pot-like recess 70 in the die members surrounding of the
head part of the functional element 10 by the sheet metal part 55 is not necessary. In the
embodiment of Fig. 7, the die button has no recess 68, but rather the base surface 188 of
the die button has been extended up to the radially outermost edge 194 of the die button
and thus forms the end face of the die button. The die button 160 of Fig. 7 has, however,
cylindrical projections 172 in the central region, with the central projection having the
same shape as the cylindrical projection 72 of the embodiment of Fig. 6. One notes from
Fig. 7 that the sheet metal part 152, which is likewise to be understood as a planar sheet
metal part prior to the attachment of the functional element 10, is likewise clamped, at
least in the region of the setting head, in the region of the head part between the end face
62 of the resiliently biased housing 57 and the end face 64 of the die button. In other
respects, the functional description and also the description of the design of the apparatus
for the embodiment of Fig. 7 is precisely the same as for the embodiment of Fig. 6,
which is why the description need not be repeated here.
Fig. 8 now shows a modified embodiment of the functional element 210, in which
the hollow cavity 218 is formed as an at least substantially cylindrical hollow space, and
the ring wall 230, which projects from the base surface of the hollow cavity 218, is
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formed as a solid cylindrical projection, the cylindrical outer surface 240 of which merges
via a rounded edge 238 into a planar end face 232.
The transition from the cylindrical hollow cavity 218 into the end face 222 of the
head part is also of rounded design, as indicated by the reference numeral 200.
One notes that in the embodiment of Figs. 8 and 9 no undercut features are
provided in the hollow cavity 218. In place of this, an undercut in the form of a ring-like
recess 202 is formed in this embodiment in the outer periphery of the head part 214. This
ring-like recess 202 is located in the region of the outer periphery between the ring nose
204 in the region of the transition from the end face 244 into the outer periphery 201 of
the head part 214 and the lower region 206 of the outer periphery of the head part 214
adjacent to the end face 222 remote from the shaft part 212.
This lower region 206 of the outer periphery of the head part 214 has a larger
diameter than the deepest point of the ring-like recess 202 and is in another respects
provided with longitudinal grooves 250 in accordance with the embodiment of Figs. 3 and
4 which serve to provide security against rotation.
It can, in other respects, be seen from Fig. 8 that a ring bead 208 exists beneath
the ring nose 204. This ring bead plays an important role during the setting movement, as
will be explained later.
In this embodiment the design of the shaft part 212 can also be selected as desired.
The insertion of the functional element 210 of the embodiment of Figs. 8 and 9 will now
be explained in more detail with reference to the Figs. 10 to 13. In this embodiment the
attachment of the functional element 210 also takes place by means of a setting head 254,
which, in accordance with the embodiment of Figs. 6 and 7, likewise has a tubular
housing part 257 which is spring-biased downwardly and a plunger 256 movable coaxially
to the housing part 257, with the plunger 256 pressing against the end face 244 of the
functional element 210 adjacent to the shaft part 212.
In deviation from the illustration of Fig. 6, the end face of the cylindrical plunger
256 is here provided with a projecting outer rim 210 and a ring-like recess 212, which
lies radially within this outer rim, so that initially only the end face of the projecting ring
region 210 enters into contact with the end face 214 of the head part 14.
Fig. 10 shows how the sheet metal material 252 is clamped in the form of a planar
13
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sheet metal panel between the end face 262 of the housing 257 and the planar end face
264 of the die button 260 at the start of the setting movement.
The die button 260 is provided in accordance with the die button of Fig. 6, with a
ring like recess 238 having a planar base surface 288 and likewise has a cylindrical
projection 272 which, however, here only has a planar end face 214 arranged
perpendicular to the longitudinal axis 224 at the top, with this end face merging via a
rounded shaping edge 216 into the cylindrical wall of the projection 272.
Likewise in deviation from the design of Fig. 6, the outer wall of the recess 268 is
in this embodiment not vertically arranged, but rather diverges in the direction towards
the end face 264 of the die button 260. The transition from the peripheral wall 284 of the
recess into the end face 264 is here likewise formed as a rounded shaping edge 218.
Fig. 11 now shows an intermediate stage of the connection of the functional
element 210 with the sheet metal part 252. One notes that the planar end face 222 of the
head part has pressed the sheet metal material 252 into the ring recess 268, with the sheet
metal material starting, as a result of the slightly conically shaped peripheral wall 284 of
the ring recess 268, to move into the grooves 250 in the lower region of the outer
periphery of the head part 214. At the same time, the cylindrical projection 272 results in
a deformation of the sheet metal material 252 into the hollow cavity 218. The end state
can then be seen in Fig. 12.
It can initially be seen from this drawing that the sheet metal material 252 hasbeen fully pressed into the recess 268 of the die button 260, with the cylindrical
projection 272 having clamped the sheet metal material between its end face 214 at the
opposite end face 232 of the cylindrical projection in the hollow cavity 218 of the head
part 214.
One also notes that during the further closing movement of the tool, the ring bead
208 has pressed into the sheet metal material 252 and, in conjunction with the slightly
conically diverging peripheral wall 216 of the die button 260 has pushed sheet metal
material into the ring-like undercut 202. The undercut 202, or the corresponding ring
recess is not fully filled out in order to provide space to receive the sheet metal material,
depending on the actual sheet metal thickness.
14
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However, in this embodiment, in addition to the above-mentioned movement, the
material of the head part of the functional element is also deformed during the closing of
the tool, and indeed in such a way that the ring collar 210 of the plunger 256 has formed
a corresponding recess in the head part 214 of the functional element, and the end face of
the plunger 256 now fully contacts the deformed end face 244 of the head part. The
material which is pressed away by this deformation has been pressed, on the one hand,
into the sheet metal material 252, and, on the other hand, however also contributed to the
movement of the sheet metal material into the undercut 202. This special design of the
end face of the plungers 256 is admittedly not essential in this embodiment. It is,
however, very useful in order to produce adequate strength in the connection between the
functional element 210 and the sheet metal part 252. Here also it can clearly be seen that
a form-fitted connection has been achieved in the region of the undercut 202, to which it
should be said that the sheet metal material 252 comes into contact on the noses of the
head part 214 formed between the grooves 250 and prevents the functional element being
pulled out. This security against rotation is achieved in this embodiment in that the sheet
material is pressed into the grooves 250.
Fig. 13 shows on the one hand a somewhat enlarged representation of the f1nal
shape in the region of the undercut 202, but also shows that the hollow cavity 218 can
additionally be provided with a ring nose 228, so that an undercut 220 also arises in this
embodiment and a hooked connection of the sheet metal material with this undercut 220
can also take place here, which has the form of a ring-like undercut.
One also sees from the representation of Fig. 13 that the cylindrical projection 230
is likewise deformed by the setting movement and that the fonning edge 238 has moved
radially outwardly as a result of this deformation and has hereby pushed the sheet metal
material into the undercut 220.
The design here in the region of the hollow cavity 218 corresponds at least
substantially to the design of the embodiment in accordance with Figs. 3 and 4. Here also
one sees that the sheet metal material has the form of a continuous membrane so that an
absolutely sealed connection was produced. All forming edges are also of rounded design
here in order to avoid as far as possible an injury of the sheet metal material in the sense
of a perforation of the latter or undesired damage to any coating that may be present.
- CA 02214730 1997-09-0~
Altonley No. 60,174-005
In this embodiment free spaces are also produced in the region of the head part and
provide additional take-up space, depending on the sheet metal thickness and the sheet
metal material.
It is namely an advantage of all the examples given here that one can work with
one and the same functional element with several different sheet metal thicknesses. It is
only necessary to adapt the die button to the sheet metal thickness.
The shape of the die button for the insertion of the embodiment of Figs. 3 and 4has not been separately shown. It has, however, substantially the same shape as the die
button of the embodiment of Fig. 6, but with the exception that the outer ring wall 284 of
the recess 268 is made slightly divergent in order to ensure a high quality form-fitted
connection with the grooves 250, without injuring the sheet metal. This conical shape is,
however, not absolutely essential during the attachment of a functional element in
accordance with Figs. 3 and 4. The slight conical shape of the die button has, however,
the additional advantage that the sheet metal part is easily released from the die button
during the opening of the tool.
Finally, the Figs. 14, lS, 16 and 17 show that the invention can also be clearlyrealized with functional elements in the form of hollow elements such as nuts. In the
Figs. 14 to 17 the reference numerals are in the same sequence as used in the
corresponding Figures 6, 7, 12 and 13. In Figures 14 and 15, the corresponding parts
and elements are numbered in the 300 sequence and parts and elements of the modified
embodiment of Figures 16 and 17 are numbered in the 400 series for reference to the
embodiments shown in the prior figures described in more detail above. The die member
160 in Figure 15 may be identical to the die member 60 of Figure 7 and is numbered in
the 100 series. A separate description of these Figs. 14 to 17 is thus not necessary. In
these Figures the hollow part 314 and 414 takes the place of the head part. It must simply
be ensured that the hollow element is not deformed in undesired manner during the
attachment, although a deformation could, under some circumstances, be intentional, for
example in order to produce a narrow portion at the entry to the hollow element. A
narrow portion of this kind could, for example, be useful to realize a snap connection
with a correspondingly shaped male part. For ease of reference, the parts are numbered
in the same sequence as the previous f1gures.
16
CA 02214730 1997-09-0~
Attomey No. 60,174-005
As examples for the sheet metal materials, which come into question, one should
name ST12 to ST15, DIN 16 and ZStE qualities 220 to 430. As far as the functional ele-
ments are concerned, one could use materials in accordance with DIN 1654 (cold heading
steels), such as frequently enter into consideration for functional elements.
All examples have the additional advantage that an extensive protection is givenagainst tilting and levering out of the functional element. This applies in particular to the
embodiments of Figs. 6, 12 and 13, with the head part 14 and 114 are clamped between
the two pot-like regions of the sheet metal part.
