Title of Invention	PUNCHED/STAMPED RIVET
Abstract	Punched/stamped rivet (1) with a rivet head (4) and an adjoining shank (5) for punching through at least two superposed joint parts (2, 3a, 3b), the shank (5) comprising at least one shank groove (6) for filling with material at least of the lower part of the joint (3a, 3b) in the punching direction during an immediately following stamping operation, characterized in that the entire punched/stamped rivet (1) is made of an aluminium oxide ceramic material reinforced with zirconium oxide.

Title of Invention

PUNCHED/STAMPED RIVET

Abstract

Punched/stamped rivet (1) with a rivet head (4) and an adjoining shank (5) for punching through at least two superposed joint parts (2, 3a, 3b), the shank (5) comprising at least one shank groove (6) for filling with material at least of the lower part of the joint (3a, 3b) in the punching direction during an immediately following stamping operation, characterized in that the entire punched/stamped rivet (1) is made of an aluminium oxide ceramic material reinforced with zirconium oxide.

Full Text	FIELD OF THE INVENTION: The invention pertains to a punched to a punched/stamped rivet as disclosed hereunder. Such punched/stamped rivets are used for connecting two or more parts, two or more types of semi-finished products, sheets, profiles and similar elements to be joined. In this case, the rivet is initially pressed through the two parts to be joined without pre-punching by means of a riveting die, wherein the rivet simultaneously functions as a punch. After the stopping point of the riveting die is reached, the parts to be joined are pressed against a lower die with the now-closed surface of riveting die and pressure pad. This causes an annular groove to be punched into the lower part to be joined around the shank end of the rivet such that the material of the lower part to be joined is pressed into at least one peripheral shank groove of the rivet. Conventional punched/stamped rivets used so far are manufactured of steel. However, problems with respect to the corrosion between the punched rivet and the parts to be joined arise when materials that tend to corrode in combination with steel connecting elements need to be joined. This is why the rivet is usually provided with a corrosion protection layer in such instances. However, this corrosion protection layer may be partially destroyed when the rivet is punched into the parts to be joined such that the desired corrosion protection can no longer be ensured. In addition, hardly any coating is suitable for use on magnesium. One also encounters problems in the subsequent mechanical processing of the rivet by means of grinding. Hereby, the corrosion protection layer of the rivet is also damaged such that the component may corrode. The invention is based on the objective of developing a punched/stamped rivet of the initially described type that eliminates the aforementioned problems. This objective is attained with a punched/stamped rivet with the characteristics of Claim 1. Advantageous embodiments and practical additional developments of the invention are disclosed in the dependent claims. The punched/stamped rivet according to the invention is manufactured of a compression-proof ceramic material with high shear strength. The rivet geometry is realized, for example, by means of an injection-molding process. The hardness of the rivet is achieved with a heat treatment after the molding process. Analogous to applications with a solid steel rivet, the ceramic rivet is pressed through the layers of parts to be joined without being destroyed. An electrochemical potential is not created between the ceramic rivet and the material of the parts to be joined. This means that electrochemical corrosion is prevented due to the utilization of a non-conductive ceramic material. The ceramic rivet can also be mechanically processed, for example, by means of a grinding machine. The punched/stamped rivet preferably consists of oxide ceramics, non-oxide ceramics or mixtures of various oxide ceramics or mixtures of various non-oxide ceramics. It was determined that an aluminum oxide ceramic reinforced with zirconium oxide is particularly suitable in this respect, wherein the ceramic material has a zirconium content of more than 60 wt% and a material density in excess of 5.2 kg/dm3. The punched/stamped rivet advantageously has a compressive strength of more than 2900 N/mm , a flexural strength in excess of 700 N/mm , a fracture toughness of more than 8 Kjc and a modulus of elasticity of less than 270 N/mm . The hardness of the punched/stamped rivet should lie below 1900 HV 10 (Vickers hardness), and the ceramic material is also gas-right and acid-resistant. Other peculiarities and advantages of the invention are discussed in the following description of one embodiment that refers to the figure. The figure shows a so-called multi-range rivet for joining workpieces of different thicknesses. The punched /stamped rivet 1 shown in the figure is realized in the form of a so-called multi- range rivet that is suitable for respectively joining an upper part 2 and a thicker lower part 3a or a thinner lower part 3b. Such a punched/stamped rivet makes it possible to join parts of different thicknesses with only one type of rivet. The punched/stamped rivet 1 is realized in the form of a solid rivet and contains a rivet head 4 in the shape of a truncated cone, as well as an adjacent cylindrical shank 5 with several adjoining shank grooves 6 arranged therein. The lower end of the shank 5 is provided with a sharp edge 7 such that punched holes can be easily produced in the respective parts to be joined 2 and 3a or 3b. In order to produce a rivet connection, this punched/stamped rivet 1 is pressed through the respective parts to be joined 2 and 3a or 3b that are fixed in position on a pressure pad from the top toward the bottom with the aid of a riveting die, not-shown, namely such that aligned holes are punched into the respective parts to be joined. After the punching process is completed, an annular depression 8 is stamped into the respective lower part to be joined 3a or 3b around the shank 5 with the aid of a corresponding die. Due to this measure, the material of the lower part to be joined 3a or 3b is subjected to a plastic deformation such that it is pressed into and fills out the shank grooves 6. The punched/stamped rivet 1 consists of an aluminum oxide ceramic that is reinforced with zirconium oxide, wherein this ceramic material has a zirconium oxide content of more than 60 wt% and a material density in excess of 5.2 kg/dm3. The invention is not limited to the multi-range rivet illustrated in the figures and described in detail in the preceding paragraphs. The punched/stamped rivet may also contain only one shank groove. Instead of notch configuration shown, the shank groove may also have a rounded or trapezoidal shape. WE CLAIM: 1. Punched/stamped rivet (1) with a rivet head (4) and an adjoining shank (5) for punching through at least two superposed joint parts (2, 3a, 3b), the shank (5) comprising at least one shank groove (6) for filling with material at least of the lower part of the joint (3a, 3b) in the punching direction during an immediately following stamping operation, characterized in that the entire punched/stamped rivet (1) is made of an aluminium oxide ceramic material reinforced with zirconium oxide. 2. Punched/stamped rivet as claimed in claim 1, wherein the aluminium oxide ceramic material reinforced with zirconium oxide has a zirconium oxide content of more than 60% by weight and a material density of more than 5.2 kg/dm3. 3. Punched/stamped rivet as claimed in claim 1 or 2, wherein it has a compression strength of more than 2900 N/nm2. 4. Punched/stamped rivet as claimed in one of claims 1 to 3, wherein it has a bending strength of more than 700 N/nm2. 5. Punched/stamped rivet as claimed in one of claims 1 to 4, wherein it has a fracture strength of more than 8 Krc. 6. Punched/stamped rivet as claimed in one of claims 1 to 5, wherein it has an E modulus of less than 270 Nmm2. 7. Punched/stamped rivet as claimed in one of claims 1 to 6, wherein it has a hardness of less than 1900 HV 10. 8. Punched/stamped rivet as claimed in one of claims 1 to 7, wherein the ceramic material is gas tight and acid resistant. Punched/stamped rivet (1) with a rivet head (4) and an adjoining shank (5) for punching through at least two superposed joint parts (2, 3a, 3b), the shank (5) comprising at least one shank groove (6) for filling with material at least of the lower part of the joint (3a, 3b) in the punching direction during an immediately following stamping operation, characterized in that the entire punched/stamped rivet (1) is made of an aluminium oxide ceramic material reinforced with zirconium oxide.

Full Text

FIELD OF THE INVENTION:
The invention pertains to a punched to a punched/stamped rivet as disclosed
hereunder.
Such punched/stamped rivets are used for connecting two or more parts, two or
more types of semi-finished products, sheets, profiles and similar elements to be
joined. In this case, the rivet is initially pressed through the two parts to be
joined without pre-punching by means of a riveting die, wherein the rivet
simultaneously functions as a punch. After the stopping point of
the riveting die is reached, the parts to be joined are pressed against a lower die with the
now-closed surface of riveting die and pressure pad. This causes an annular groove to be
punched into the lower part to be joined around the shank end of the rivet such that the material
of the lower part to be joined is pressed into at least one peripheral shank groove of the rivet.
Conventional punched/stamped rivets used so far are manufactured of steel. However,
problems with respect to the corrosion between the punched rivet and the parts to be joined arise
when materials that tend to corrode in combination with steel connecting elements need to be
joined. This is why the rivet is usually provided with a corrosion protection layer in such
instances. However, this corrosion protection layer may be partially destroyed when the rivet is
punched into the parts to be joined such that the desired corrosion protection can no longer be
ensured. In addition, hardly any coating is suitable for use on magnesium. One also encounters
problems in the subsequent mechanical processing of the rivet by means of grinding. Hereby, the
corrosion protection layer of the rivet is also damaged such that the component may corrode.
The invention is based on the objective of developing a punched/stamped rivet of the
initially described type that eliminates the aforementioned problems.
This objective is attained with a punched/stamped rivet with the characteristics of Claim
1. Advantageous embodiments and practical additional developments of the invention are
disclosed in the dependent claims.
The punched/stamped rivet according to the invention is manufactured of a
compression-proof ceramic material with high shear strength. The rivet geometry is realized, for
example, by means of an injection-molding process. The hardness of the rivet is achieved with a
heat treatment after the molding process. Analogous to applications with a solid steel rivet, the
ceramic rivet is pressed through the layers of parts to be joined without being destroyed.
An electrochemical potential is not created between the ceramic rivet and the material of
the parts to be joined. This means that electrochemical corrosion is prevented due to the
utilization of a non-conductive ceramic material. The ceramic rivet can also be mechanically
processed, for example, by means of a grinding machine.
The punched/stamped rivet preferably consists of oxide ceramics, non-oxide ceramics or
mixtures of various oxide ceramics or mixtures of various non-oxide ceramics. It was determined
that an aluminum oxide ceramic reinforced with zirconium oxide is particularly suitable in this
respect, wherein the ceramic material has a zirconium content of more than 60 wt% and a
material density in excess of 5.2 kg/dm3. The punched/stamped rivet advantageously has a
compressive strength of more than 2900 N/mm , a flexural strength in excess of 700 N/mm , a
fracture toughness of more than 8 Kjc and a modulus of elasticity of less than 270 N/mm . The
hardness of the punched/stamped rivet should lie below 1900 HV 10 (Vickers hardness), and the
ceramic material is also gas-right and acid-resistant.
Other peculiarities and advantages of the invention are discussed in the following description of
one embodiment that refers to the figure. The figure shows a so-called multi-range rivet for
joining workpieces of different thicknesses.
The punched /stamped rivet 1 shown in the figure is realized in the form of a so-called multi-
range rivet that is suitable for respectively joining an upper part 2 and a thicker lower part 3a or
a thinner lower part 3b. Such a punched/stamped rivet makes it possible to join parts of different
thicknesses with only one type of rivet. The punched/stamped rivet 1 is realized in the form of a
solid rivet and contains a rivet head 4 in the shape of a truncated cone, as well as an adjacent
cylindrical shank 5 with several adjoining shank grooves 6 arranged therein. The lower end of
the shank 5 is provided with a sharp edge 7 such that punched holes can be easily produced in
the respective parts to be joined 2 and 3a or 3b.
In order to produce a rivet connection, this punched/stamped rivet 1 is pressed through the
respective parts to be joined 2 and 3a or 3b that are fixed in position on a pressure pad from the
top toward the bottom with the aid of a riveting die, not-shown, namely such that aligned holes
are punched into the respective parts to be joined. After the punching process is completed, an
annular depression 8 is stamped into the respective lower part to be joined 3a or 3b around the
shank 5 with the aid of a corresponding die. Due to this measure, the material of the lower part
to be joined 3a or 3b is subjected to a plastic deformation such that it is pressed into and fills out
the shank grooves 6.
The punched/stamped rivet 1 consists of an aluminum oxide ceramic that is reinforced with
zirconium oxide, wherein this ceramic material has a zirconium oxide content of more than 60
wt% and a material density in excess of 5.2 kg/dm3.
The invention is not limited to the multi-range rivet illustrated in the figures and described in
detail in the preceding paragraphs. The punched/stamped rivet may also contain only one shank
groove. Instead of notch configuration shown, the shank groove may also have a rounded or
trapezoidal shape.
WE CLAIM:
1. Punched/stamped rivet (1) with a rivet head (4) and an adjoining
shank (5) for punching through at least two superposed joint parts (2,
3a, 3b), the shank (5) comprising at least one shank groove (6) for
filling with material at least of the lower part of the joint (3a, 3b) in
the punching direction during an immediately following stamping
operation, characterized in that the entire punched/stamped rivet (1) is
made of an aluminium oxide ceramic material reinforced with
zirconium oxide.
2. Punched/stamped rivet as claimed in claim 1, wherein the aluminium
oxide ceramic material reinforced with zirconium oxide has a zirconium
oxide content of more than 60% by weight and a material density of
more than 5.2 kg/dm3.
3. Punched/stamped rivet as claimed in claim 1 or 2, wherein it has a
compression strength of more than 2900 N/nm2.
4. Punched/stamped rivet as claimed in one of claims 1 to 3, wherein it
has a bending strength of more than 700 N/nm2.
5. Punched/stamped rivet as claimed in one of claims 1 to 4, wherein it
has a fracture strength of more than 8 Krc.
6. Punched/stamped rivet as claimed in one of claims 1 to 5, wherein it
has an E modulus of less than 270 Nmm2.
7. Punched/stamped rivet as claimed in one of claims 1 to 6, wherein it
has a hardness of less than 1900 HV 10.
8. Punched/stamped rivet as claimed in one of claims 1 to 7, wherein the
ceramic material is gas tight and acid resistant.
Punched/stamped rivet (1) with a rivet head (4) and an adjoining shank (5)
for punching through at least two superposed joint parts (2, 3a, 3b), the
shank (5) comprising at least one shank groove (6) for filling with material at
least of the lower part of the joint (3a, 3b) in the punching direction during
an immediately following stamping operation, characterized in that the entire
punched/stamped rivet (1) is made of an aluminium oxide ceramic material
reinforced with zirconium oxide.

Documents:

1339-KOLNP-2005-FORM 27.pdf

1339-kolnp-2005-granted-abstract.pdf

1339-kolnp-2005-granted-claims.pdf

1339-kolnp-2005-granted-correspondence.pdf

1339-kolnp-2005-granted-description (complete).pdf

1339-kolnp-2005-granted-drawings.pdf

1339-kolnp-2005-granted-examination report.pdf

1339-kolnp-2005-granted-form 1.pdf

1339-kolnp-2005-granted-form 18.pdf

1339-kolnp-2005-granted-form 2.pdf

1339-kolnp-2005-granted-form 26.pdf

1339-kolnp-2005-granted-form 3.pdf

1339-kolnp-2005-granted-form 5.pdf

1339-kolnp-2005-granted-reply to examination report.pdf

1339-kolnp-2005-granted-specification.pdf

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Patent Number

227634

Indian Patent Application Number

1339/KOLNP/2005

PG Journal Number

03/2009

Publication Date

16-Jan-2009

Grant Date

14-Jan-2009

Date of Filing

12-Jul-2005

Name of Patentee

KERB-KONUS-VERTRIERS-GMBH

Applicant Address

WERNHER-VON-BRAUN-STRASSE 7, 92224 AMBERG

Inventors:

#	Inventor's Name	Inventor's Address
1	DONHAUSER, GEORG	BERNRICHT 3, 92224 AMBERG

PCT International Classification Number

F 16 B 19/06

PCT International Application Number

PCT/EP2003/013756

PCT International Filing date

2003-12-05

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	10301114.5	2003-01-14	Germany