U.S. patent application number 10/791165 was filed with the patent office on 2004-11-04 for metal fixing material bushing and method for producing a base plate of a metal fixing material bushing.
Invention is credited to Bender, Richard, Fink, Thomas, Forster, Bartholomaus, Heeke, Neil, Olzinger, Adolf, Pfeiffer, Thomas, Ranftl, Reinhard.
Application Number | 20040216631 10/791165 |
Document ID | / |
Family ID | 32830906 |
Filed Date | 2004-11-04 |
United States Patent
Application |
20040216631 |
Kind Code |
A1 |
Fink, Thomas ; et
al. |
November 4, 2004 |
Metal fixing material bushing and method for producing a base plate
of a metal fixing material bushing
Abstract
A glass-to-metal bushing for ignitors of airbags or belt
tensioning pulleys. A metal pin is arranged in a slot in the base
plate in the fixing material, the base plate being formed by one
element whereby the base geometry describing the slot is produced
by at least one separation process. Structure is provided between
the front and rear of the base plate for preventing relative motion
of the fixing material in the direction of the base plate rear
portion across from the inner circumference of the slot.
Inventors: |
Fink, Thomas; (Landshut,
DE) ; Heeke, Neil; (Golden, CO) ; Olzinger,
Adolf; (Ergolding, DE) ; Pfeiffer, Thomas;
(Kumhausen, DE) ; Ranftl, Reinhard;
(Pfeffenhausen, DE) ; Bender, Richard; (Lauf,
DE) ; Forster, Bartholomaus; (Essenbach-Oberahrain,
DE) |
Correspondence
Address: |
BAKER & DANIELS
111 E. WAYNE STREET
SUITE 800
FORT WAYNE
IN
46802
|
Family ID: |
32830906 |
Appl. No.: |
10/791165 |
Filed: |
March 2, 2004 |
Current U.S.
Class: |
102/200 |
Current CPC
Class: |
Y10T 428/12535 20150115;
F42B 3/198 20130101; F42B 3/103 20130101 |
Class at
Publication: |
102/200 |
International
Class: |
F42C 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 3, 2003 |
DE |
203 03 413.9 |
Mar 10, 2003 |
DE |
103 21 067.9 |
Jun 11, 2003 |
DE |
103 26 253.9 |
Sep 20, 2003 |
DE |
203 14 580.1 |
Claims
1. Metal fixing material bushing for igniters of airbags or belt
tensioning pulleys, in particular glass to metal bushing; with at
least one metal pin which is arranged in a slot in the base plate
in a fixing material, whereby the base plate has a front and a rear
characterized by the following features: the base plate is formed
by one element, whereby the base geometry describing the slot is
produced by at least one separation process; resources are provided
between the front and rear of the base plate for prevention of a
relative motion of fixing material in the direction of the rear
across from the inner circumference of the slot.
2. Metal fixing material bushing according to claim 1,
characterized by the fact that the contour describing the final
geometry is produced by the separation process.
3. Metal fixing material bushing according to claim 1 or whose
resources are an integral component of the base plate or form a
structural unit with them.
4. Metal fixing material bushing according to claim 1,
characterized by the fact that the metal fixing material bushing
comprises at least two metal pins in parallel arrangement to each
other.
5. Metal fixing material bushing according to claim 1,
characterized by the fact that the metal pin is firmly connected
with a fixing material yielding a fixing material plug.
6. Metal fixing material bushing according to claim 5,
characterized by the fact that the metal pin is sealed with the
fixing material.
7. Metal fixing material bushing according to claim 1,
characterized by the fact that a glass plug formed from molten
glass or a high-performance polymer is used as fixing material.
8. Metal fixing material bushing according to claim 1,
characterized by the fact that the resources for prevention of a
relative motion of fixing material in the direction of the rear
across from the inner circumference of the slot comprise at least
one undercut arranged between the rear and the front viewed from
the rear on the inner circumference of the slot in the base plate,
whereby the front is free from such an undercut.
9. Metal fixing material bushing according to claim 8,
characterized by the fact that the undercut is formed by at least
one projection.
10. Metal fixing material bushing according to claim 9,
characterized by the following features: the slot is characterized
by two sub-areas--a first sub-area which extends from the rear
toward the front and a second sub-area, which extends from the
front toward the rear; the projection is formed by the second
sub-area, which is characterized by lesser inner dimensions than
the first sub-area; the first and second sub-areas have an
unchanging geometry with constant inner dimensions over their
length.
11. Metal fixing material bushing according to claim 9,
characterized by the following features: the slot is characterized
by two sub-areas--a first sub-area which extends from the rear
toward the front and a second sub-area, which extends from the
front toward the rear; the projection is formed by the second
sub-area, which is characterized by lesser inner dimensions than
the first sub-area; the first and/or second sub-areas have a
variable geometry and/or different inner dimensions over their
length.
12. Metal fixing material bushing according to claim 11,
characterized by the fact that the first sub-area is characterized
by a reduction of the dimensions starting from the front to the
second sub-area.
13. Metal fixing material bushing according to claim 11,
characterized by the fact that the slot exhibits a circular cross
section and at least the first sub-area, preferably also the second
sub-area is tapered.
14. Metal fixing material bushing according to claim 8,
characterized by the fact that undercut is centrally arranged.
15. Metal fixing material bushing according to claim 8,
characterized by the following features: with an undercut in both
directions; the slot is characterized by three sub-areas--a first
sub-area, which extends from the rear toward the front, a second
sub-area adjacent to the first sub-area and a third sub-area, which
extends from the front to the rear; the second sub-area is
characterized by lesser dimensions of the slot than the first and
third sub-areas.
16. Metal fixing material bushing according to claim 8,
characterized by the following features: with an undercut in both
directions; the slot is characterized by three sub-areas--a first
sub-area, which extends from the rear toward the front, a second
sub-area adjacent to the first sub-area and a third sub-area, which
extends from the front to the rear; the second sub-area is
characterized by greater dimensions of the slot than the first and
third sub-areas.
17. Metal fixing material bushing according to claim 15,
characterized by the fact that the first and third sub-areas are
characterized by identical cross section dimensions.
18. Metal fixing material bushing according to claim 9,
characterized by the fact that a number of projections are provided
arranged in circumferential direction distanced to each other on a
common length between the front and the rear.
19. Metal fixing material bushing according to claim 1,
characterized by the fact that the slot exhibits a circular cross
section.
20. Metal fixing material bushing according to claim 1,
characterized by the fact the slot exhibits a randomly selectable
cross section.
21. Metal fixing material bushing according to claim 1,
characterized by the fact that the base plate is formed by a
stamped metal part.
22. Metal fixing material bushing according to claim 21,
characterized by the fact that the stamped metal part is
polished.
23. Metal fixing material bushing according to claim 1,
characterized by the fact that the resources for prevention of a
relative motion of fixing material in the direction of the rear
across from the inner circumference of the slot comprise at least
one positive connection between fixing material plug and a part of
the slot.
24. Metal fixing material bushing according to claim 1,
characterized by the fact that the resources comprise an element
inserted in the slot and the inner circumference of the slot and/or
the outer circumference of the element exhibits a roughness of
.gtoreq.10 .mu.m.
25. Metal fixing material bushing according to claim 1,
characterized by the fact that on the metal pin resources are
provided for the prevention of a relative motion of the pin
opposite the fixing material.
26. Metal fixing material bushing according to claim 15,
characterized by the fact that the resources for prevention of a
relative motion of the pin opposite the fixing material comprise at
least one projection in radial direction on the pin.
27. Metal fixing material bushing according to claim 26,
characterized by the fact that the projection is an integral
component of the pin.
28. Metal fixing material bushing according to claim 26,
characterized by the fact that the projection is formed by an
element connected to the pin.
29. Metal fixing material bushing according to claim 26,
characterized by the fact that the resources for the prevention of
a relative motion of the pin opposite the fixing material comprise
a number of projections adjoined in axial direction and in radial
direction on the pin.
30. Metal fixing material bushing according to claim 1,
characterized by the fact that at least two metal pins are
provided.
31. Metal fixing material bushing according to claim 30,
characterized by the fact that the two or more metal pins are in
parallel arrangement to each other.
32. Metal fixing material bushing according to claim 30,
characterized by the fact that the second metal pin is grounded to
the rear of the base plate.
33. Metal fixing material bushing according to claim 1,
characterized by the fact that a metal pin is provided, which is
arranged in a slot in the base plate in a fixing material, as well
as a socket of the base plate which is grounded.
34. Method for manufacturing a base plate of a metal bushing
according to claim 1, in which from one part, in particular a sheet
metal part, of predefined thickness the final contour describing
the outer geometry is gained by means of a separation process; in
which to form the slot for at least one metal pin the base geometry
describing the starting form of the slot is gained by means of
punching out of the part, in particular of the sheet metal
part.
35. Method according to claim 34, characterized by the fact that
the final contour describing the outer geometry gained by the
separation process and the base geometry describing the starting
form of the slot are produced in one processing step in the form of
punching out with a tool.
36. Method according to claim 34, characterized by the fact that
the undercuts in the slots are formed by deformation of the
slot.
37. Method according to claim 36, characterized by the fact that
the deformation is achieved by means of at least one stamping
operation.
38. Method according to claim 36, characterized by the fact that
the stamping and punching operations are performed from the same
side on the base plate.
39. Method according to claim 36, characterized by the fact that
the stamping and punching operations are performed from at
different sides on the base plate.
40. Method according to claim 36, characterized by the fact that
the stamping and punching operations are performed on both sides on
the base plate.
41. Method according to claim 40, characterized by the fact that
either tools with the same parameters or the same tools are used
for stamping and punching.
42. Method according to one claim 34, characterized by the fact
that prior to the punching out of the slot in the area of the slot
to be produced on the sheet metal part a stamping operation is
performed.
43. Method according to one claim 34, characterized by the fact
that the socket of the base plate is obtained after punching out by
means of deep drawing.
Description
[0001] The invention relates to a metal fixing material bushing, in
particular with the features of the generic part of claim 1;
further a method for the production of a base plate of a metal
fixing material bushing, in particular with the features from the
generic part of claim 23.
[0002] Metal fixing material bushings are anticipated in the state
of the art in various designs. By metal fixing material bushings,
vacuum-tight sealings of fixing materials are understood, in
particular sealings of glasses to metals. The metals act as
electric conductors. As representatives, we make reference to U.S.
Pat. No. 5,345,872, U.S. Pat. No. 3,274,937. Such bushings are
common in electronics and in electrical engineering. The glass used
for sealing serves as an insulator. Typical metal fixing material
bushings are built in such a way, that metallic inner conductors
are sealed in a preformed sintered glass part, whereby the sintered
glass part or the glass tube in an outer metal part is sealed with
the so-called base plate. For example, igniters are preferred
applications of such metal fixing material bushings. Said igniters
are used among other things for airbags or belt tensioning pulleys
in motor vehicles. In this case the metal fixing material bushings
are components of an ignition device. In addition to the metal
fixing material bushing, the entire ignition device comprises a
spark gap, the explosive as well as a metal cover, which tightly
encapsulates the ignition mechanism. Either one or two or more than
two metallic pins can be passed through the bushing. In a preferred
implementation with one metallic pin the casing is grounded, in a
preferred two-pole embodiment it grounded to one of the pins. The
previously described ignition device is used in particular for air
bags or belt tensioning pulleys in motor vehicles. Known devices of
the named or similar type are described in U.S. Pat. No. 6,274,252,
U.S. Pat. No. 5,621,183, DE 29 04 174 A1 or DE 199 27 233 A1, whose
disclosure content is fully included in the present application.
The previously named ignition units have two metal pins. However,
electronic ignition devices are also possible with only a single
pin. The ignition devices shown in the state of the art comprise a
metal base plate, for example a metal sleeve, which is constructed
as a swivel part. The metal base plate exhibits at least one slot
through which at least one metal pin is passed. One significant
problem of this design consists in the fact that such a design is
both material and cost-intensive.
[0003] The invention is therefore based on the object of creating a
metal fixing material bushing of the initially named type in such a
way that it is characterized by a high strength with low material
and labor expenses and by a suitability for higher stresses and
further that assembly errors, which result from the inaccurate
correspondence of the individual elements, are avoided.
[0004] The invention's solution is characterized by the features of
claim 1. The procedural implementation for production of a base
plate is described in claim 34. Advantageous developments are
reproduced in the dependent claims.
[0005] The metal fixing material bushing comprises a metal base
plate, through which at least one metal pin is passed. If two metal
pins are provided in a preferred embodiment, one of the two pins at
least directly or indirectly via additional elements establishes
the ground connection to the base plate. In the implementation with
two metal pins these metal pins are preferably arranged parallel to
one another. At least one of the metal pins is arranged in a slot
in the base body and fixed across from said base body by means of
fixing material, preferably in the form of a glass plug. As per the
invention the base plate is formed by a sheet metal element,
whereby in a first embodiment at least the slot is produced by
means of a separation process, in particular punching.
[0006] The base plate itself is preferably also punched out of a
solid material, the final geometry of the base plate however is
retained by means of a forming process for example deep drawing. In
a preferred embodiment the final geometry describing the exterior
contour and the base geometry describing the slot is produced at
least by means of one separation process, in particular punching.
Final geometry means that no more forming processes have to be
performed on it. Base geometry means that it either represents the
final geometry in the case of no further necessary changes or that
changes can still be undertaken to said base geometry by means of
further manufacturing methods, in particular forming methods,
whereby the final geometry is not achieved until after these
additional methods. Resources are provided between the front and
the rear for avoiding a relative motion of fixing material in the
direction of the rear toward the inner circumference of the slot.
The resources are integrable components of the base plate or form
together with the base plate a structural unit.
[0007] The production of the geometry by means of a separation
process means that the final geometry on the outer circumference of
the base plate is produced by means of blanking and the geometry of
the slot is produced by means of punching. The resources for
avoiding a relative motion of fixing material in the direction of
the rear toward the inner circumference of the slot are provided
for the purpose of getting control of the difficulties resulting
from the sealing of the single metal pin in a slot and also for the
purpose of security against a withdrawal of the unit fixing
material and metal pin. Said resources act as a kind of barb and
lead in the case of relative motion in the direction of the rear to
a positive locking between fixing material plugs, in particular
glass plug and base plate. These comprise for example at least one
local contraction in the slot, whereby they can be provided in the
entire region of the inner circumference, except for the front of
the base plate.
[0008] The solution of the invention makes it possible to resort to
a more cost-effective manufacturing method and starting materials,
whereby the inventory is considerably minimized. Additionally, the
entire base plate can be designed as an integral component, into
which the metal pin is sealed by means of fixing material. Another
significant advantage consists in the fact that even under
increased loads on the single metal pin, for example a pressure
load, a pressing out of the metal pin with the glass plug from the
port slot is safely prevented. The overall design also builds
smaller in width and is also applicable at a slighter size through
the guarantee of the secure fixing of the metal pin in the base
plate, even with higher loads.
[0009] Critical in the process is the fact that the local
contraction of the cross section in the region of the rear or
between the rear and front occur, whereby however the front is
always characterized by a greater diameter.
[0010] In accordance with an especially advantageous design the
second metal pin is grounded or fastened to ground as a ground pin
on the rear of the base plate. As a result of this, additional
measures for grounding a metal pin fixed in the base plate with
fixing material or electrically coupling it to the base plate are
no longer needed. Further, there is still only one pin to be fixed
in a slot, whereby the possibilities for securely fixing the single
pin completely in circumferential direction become more varied and
the potential connecting surface for the ground pin can be
enlarged.
[0011] For example a glass plug, a ceramic plug, a glass-ceramic
plug or a high-performance polymer can be used as fixing
material.
[0012] A number of possibilities exist for the concrete development
of the resources for prevention of a relative motion between the
fixing material and slot, in particular slipping out. These are
characterized by measures on the base plate. In the simplest case
measures on the base plate are resorted to, which can be
implemented in production, particularly during the punching
process. In the process the slot between the rear and the front is
characterized by a change of the cross-sectional contour. In the
simplest case at least two areas of variable inside dimensions are
provided in the design as slot with circular cross section with
variable diameter. In the process the cross-sectional change can
take place in stages or continuously. In the latter case the slot
between the front and rear is tapered in design, whereby said slot
narrows to the rear.
[0013] The measures on the base plate are as a rule further
characterized by the provision of several recesses or projections.
These form at least one undercut arranged between the rear and the
front viewed on the inner circumference of the slot in the base
plate, whereby the front is free of such undercuts. In the
symmetrical construction of the slot this is characterized by three
sub-areas--a first sub-area, which extends from the rear in the
direction of the front, a second sub-area connected to the first
one and a third sub-area, which extends from the front in the
direction of the rear. The second sub-area is characterized by
slighter or greater dimensions of the slot than the first and third
sub-areas. Preferably the first and second sub-areas are then
characterized by identical cross-sectional dimensions.
[0014] In implementations with more than two areas of variable
dimensions, in particular with variable diameters methods are
selected which result from machining both sides of the base plate.
If in the previously described implementations an asymmetrical
shape of the slot is intended, with these implementations with more
than two areas preferably a development of the slot is selected
which can be used in any way with regard to the mounting position.
This is, relative to a theoretical center line which runs
vertically to the pin axis of the pin in the base plate and which
extends in the central area of the base plate, symmetrically
designed. Therewith the front and the rear can, with regard to
their function, also be exchanged. The undercuts formed by these
counteract possible movements of the fixing material plug in both
directions.
[0015] In accordance with a further design there can also be a
multiple number of projections arranged in circumferential
direction distanced to each other on a common length between the
front and the rear. These are as a rule produced by stamping, i.e.
local forming under pressure in the area of the rear. The
manufacturing process is thus especially cost-effective.
[0016] Another option for prevention of relative motions between
fixing material plug and port consists in the forming of a positive
connection between them. For example, normally the glass is placed
in the opening together with the metal pin, the glass and metal
ring are heated up, so that after the cooling the metal heat
shrinks onto the glass plug. In general the slot exhibits in
essence the final diameter after the punching of the slot.
Naturally the punched slot can itself be machined, for example
polished without the final diameter changing significantly. The
slot can have a circular cross section. Other possibilities are
conceivable, for example an oval cross section.
[0017] In accordance with an advantageous further development for
additional prevention of relative motions under load between metal
pin and fixing material measures on the metal pin are provided. In
this process this can be a matter of projections or recesses
extending over the entire outer circumference of the metal pin or
with random or fixed predefined projections arranged next to each
other in circumferential direction.
[0018] The method for manufacturing a base plate of a metal bushing
is characterized by the fact that the end contour describing the
outer geometry is gained by means of a separation process free of
machining from a sheet metal part of predefined thickness. The
achievement of the base geometry describing the form of the slot
for formation of the slot also occurs for at least one metal pin by
means of punching out of the sheet metal part. In the process both
operations can be in cost-saving fashion in a single tool and one
processing step. The undercuts in the slots are developed by means
of deformation of the slots, for example by means of stamping. The
single stamping operation can be undertaken before or after the
punching operation. Preferably the stamping and punching operation
take place on the same side of the base plate, to avoid unnecessary
workpiece position changes and perhaps have these processes run one
immediately after the other.
[0019] Corresponding to the desired geometries to be attained the
stamping operations occur either on one side or both sides, whereby
in the latter case preferably identical stamping parameters are
set, in order to ensure a symmetrical implementation of the
slot.
[0020] The invention's solution is explained in detail in the
following using figures. The figures show the following:
[0021] FIG. 1a illustrates a first embodiment of a metal fixing
material bushing designed as per the invention;
[0022] FIGS. 1b through 1e illustrate in greatly simplified
diagrammatic view the basic principle of a method as per the
invention for manufacturing a base plate in accordance with the
invention;
[0023] FIG. 2a illustrates a second embodiment of a metal fixing
material bushing designed as per the invention with tapered design
of the slot;
[0024] FIGS. 2b through 2c illustrate a further embodiment of the
method as per the invention for manufacturing a base plate in
accordance with FIG. 2a after a punching operation;
[0025] FIG. 3 illustrates a third embodiment of a metal fixing
material bushing designed as per the invention with partially
tapered design of the slot;
[0026] FIG. 4 illustrates an embodiment of the metal fixing
material bushing designed as per the invention with a projection
between the front and rear in the contour describing the slot;
[0027] FIG. 5 illustrates an embodiment of the metal fixing
material bushing designed as per the invention with a recess
between the front and rear in the contour describing the slot;
[0028] FIG. 6 illustrates an implementation as per FIG. 1a with
additional projections on the metal pin;
[0029] FIG. 7 illustrates a further development as per FIG. 6;
[0030] FIG. 8 illustrates a further embodiment of the metal fixing
material bushing designed as per the invention with punctual
contraction of the cross section in the region of the rear;
[0031] FIG. 9 illustrates an embodiment of the metal fixing
material bushing designed as per the invention with surface
texturing in the slot;
[0032] FIG. 10 illustrates a further alternative embodiment of the
metal fixing material bushing designed as per the invention;
[0033] FIG. 11 illustrates an embodiment with a metal pin, a
so-called mono-pin.
[0034] FIG. 1a illustrates a first implementation of a metal fixing
material bushing 1 designed as per the invention using an axial
section, for example for use as an igniter of an airbag. This
comprises a base plate 3 forming a metal collar 2, with which two
parallel metal pins 4 and 5 are electrically coupled. The two metal
pins 4 and 5 are arranged parallel to one another. In the process
one acts as a conductor, while the second pin is grounded. In the
represented case the first metal pin 4 acts as a conductor and
metal pin 5 acts as the ground pin. At least one of the metal pins,
in particular the metal pin 4 acting as the conductor is guided
through the base plate 3. In the represented case the ground pin 5
is directly attached to the rear 12 of the base plate 3. The metal
pin 4 is for this purpose sealed on a part l.sub.1 of its length l
in fixing material 34, particularly on a glass plug 6 cooled from
molten glass. The metal pin 4 protrudes at least on one side over
the face 7 of the glass plug 6 and in the represented embodiment
seals flush with the second face 8 of the glass plug 6. Other
variants are also conceivable. Preferably not only the slot, but
also the base plate 3 is designed as punched element 9. This means
that the geometry describing the outer contour, in particular the
outer circumference 10 is produced by means of blanking, preferably
punching. The punch part can either continue to be used in the
geometry as it is present after the punching operation or can be
deformed in a further operation, for example it can be deep drawn.
The slot 11 provided receiving and fixing of the metal pin 4 by
means of the glass plug 6 is produced in a preferred embodiment by
means of a punching operation in the form of slotting. Subsequently
the metal pin 4 is inserted at the rear 12 of the metal fixing
material bushing 1 together with the glass plug into the slot 11
and the metal plate containing the glass plug and the metal pin is
heated, so that after a cooling operation the metal heat shrinks
and in this way a non-positive connection between glass plug 6 with
metal pin 4 and base plate 3 is formed. It is also conceivable to
insert the fixing material in molten or fluid state, in particular
the molten glass of the front 13 into the slot 11. During the
cooling a positive and material connection incorporated into the
material comes into being both between the outer circumference 14
of the metal pin 4 as well as between the inner circumference 15 of
the slot 11. To prevent a loosening of the metal pin 4 with the
glass plug 6 from the base plate 3 in the case of stress of the
entire metal fixing material bushing 1 during ignition, resources
for prevention of a relative motion between fixing material 34 and
inner circumference 15 of the slot in the direction of the rear 12,
said resources being marked with 35 here. These act sort of as a
barb and bring about a positive locking between base plate 3 and
glass plug 6 under tensile force influence and/or pressure on the
glass plug 6 and/or the metal pin 4 and prevent therewith a
slipping out at the rear 12. For this purpose as per a first
embodiment the slot 11 is designed in such a way that it has an
undercut 36, which is formed by a projection 37. This projection is
arranged in the region of the rear 12 and in the represented case
closes flush with it. The slot 12, which in the represented case is
preferably designed with a circular cross section, is characterized
through this projection 37 by means of two different diameters
d.sub.1 and d.sub.2.
[0035] Diameter d.sub.1 is greater than diameter d.sub.2. Diameter
d.sub.2 is the diameter of the slot 11 at the rear 12. Diameter
d.sub.1 is the diameter of the slot 11 at the front 13. Thereby the
slot 11 is executed over a significant part of its extent 1.sub.d1
with the same diameter d.sub.1. l.sub.d2 stands for the design of
slot 11 with diameter d.sub.2. That is, the slot has two sub-areas,
a first sub-area 16 and a second sub-area 17, whereby the first
sub-area 16 is characterized by diameter d.sub.1 and the second
sub-area 17 is characterized by diameter d.sub.2. These diameters
are produced thereby by means of a single-sided stamping operation
in the form of slotting of the sides of the front 13 or rear 12
with subsequent deformation operation under the influence of
pressure, particularly stamping, as represented in FIGS. 1b through
1c on base plate 3. Preferably the punching and deformation
operation each occur from the same side, in the represented case
from the front 13. The blanking of base plate 3 can also take place
within the framework of a punching operation or a preceding cutting
operation, for example water-jet cutting or laser-beam cutting.
Preferably this takes place however by means of punching. The tool
for this is designed in such a way that the entire base plate 3
with a slot 11 is punched out in one processing step out of sheet
metal 38 of a specified sheet thickness b, which corresponds to a
thickness D of base plate 3.
[0036] FIGS. 1b through 1e illustrates in diagrammatically
simplified representation the basic principle of the invention's
method for manufacturing of a base plate 3 with the required
geometry. FIG. 1b illustrates in diagrammatically simplified
representation the design of the punching tool 39 out of two
sub-tools, one bottom part in the form of a die 40 and one upper
part in the form of a punch 41. In the process the punch 41 moves
toward the sheet metal 38 lying on matrix 10. The feed direction is
designated by an arrow. The base plate 3' resulting from this with
regard to its outer final geometry and the geometry of the slot
11'
[0037] after the punching is reproduced in FIG. 1c. The base plate
3' can in this state and this position undergo a further stamping
operation, in order to achieve the geometry of the slot 11 shown in
FIG. 1a, I particular the undercut 36 formed by the projection 37.
The stamping tool 42 is allocated to the front 23 of the base plate
3' and is active on the slot 11", as present after the punching,
from the side of the front 12 in the direction of the rear 12. The
active depth t.sub.1, which in the final state of the base plate 3
characterizes the distance of the undercut 36 from the front 13 is
guaranteed in the process by means of the form of the stamping tool
42 and the stamp depth conditioned by it or else only through the
stamp depth. FIG. 1e illustrates the position of the stamping tool
42 toward the base plate 3' in the final state, i.e. after
successful stamping, whereby in this state the base plate 3'
corresponds to the base plate 3. The finishing metals characterize
the state of the element to be machined during production. In order
to achieve an optimum stamping result, metallic materials with good
flowability in the selected pressure impact are used as sheet
metals 38 or thin elements. Preferably CuNi alloys or Al alloys or
Ni or Fe alloys are used as metals. The use of steels, for example
stainless steel, CRS 1010, constructional steels or Cr--Ni steel is
particularly preferable.
[0038] In the implementation shown in FIGS. 1a through 1e the slot
11 has a circular cross section. However, other forms are also
conceivable, whereby in this case an undercut is formed by means of
changing the inner dimensions of the opening. Further the displayed
geometries are reproduced idealized. For example, in practice, as a
rule surface areas that are not completely at right angles to each
other will develop. It is crucial that a base contour of the slot
be created, which for one does justice to the reception of a sealed
metal pin and further the prevention of an outward movement of the
totality of metal pin and fixing material, in particular the glass
plug, i.e. also the surface areas forming the undercut and the
adjacent surface areas can be arranged at an angle to each
other.
[0039] FIG. 2a illustrates a further design of the base plate 3.2
using an axial cut through a metal fixing material bushing 1.2. The
base structure of the metal fixing material bushing 1.2 corresponds
to the one described in FIG. 1, for which reasons the same
reference symbols are used for the same elements. In the
implementation as per FIG. 2a the slot 11.2 is however has a
tapered design. In the process diameter d proceeding from the front
13.2 to the rear 12.3 decreases steadily. This steady decrease in
diameter by means of the formation of a cone embodies the resource
35 for the prevention of a relative motion between the fixing
material and the inner circumference 15 of the slot.
[0040] FIG. 2b illustrates the base plate 3' resulting after the
punching operation after stamping. A slot 11' can be seen with
equal dimensions throughout. FIG. 2c illustrates the stamping tool
43, which has a tapered design and acts on the base plate 3' as per
FIG. 2b from the front 13.2 against a die 44. In contrast to this,
FIG. 3 discloses a combination of the implementation according to
FIGS. 1 and 2, in which only a part of the slot 11.3 has a tapered
design. In this implementation the slot 11.3 of the metal fixing
material bushing 13, particularly in base plate 3.3 is also divided
into two sections, a first sub-area 16.3 and a second sub-area
17.3. The second sub-area 17.3 is characterized by a constant
diameter d.sub.2.3 over its length l.sub.d2.3. The second sub-area
17.3 extends from the rear 12.3 toward the front 13.3 The first
sub-area 16.3 is characterized by a constant cross section
reduction of the slot 11.3. The reduction takes place from a
diameter d1.3 up to a diameter d2.3. The low diameters at the rears
12.2, 12.3 as per the implementations of FIGS. 2 and 3 offer the
advantage of a greater connecting surface 19 for metal pin 5.2 or
5.3, in particular for the ground pin. The undercut 36.3 results on
the basis of the diameter change viewed from the second to the
first sub-area 16.3.
[0041] In all of the embodiments shown in FIGS. 1 through 3 the
asymmetrical geometry of the slot 11, when considered from the
front 13 to the rear 12, offers the advantage of prevention of a
slipping or pulling out of the glass plug 6 at the rear 12 or in
the direction of the rear. Additionally, during the assembly as a
result of the asymmetrical geometry there can be an easier
orientation for the mounting position of the individual elements,
in particular the metal pins 4 and 5. On the basis of the undercut
a loosening of the constructional unit from metal pin 4 and the
glass plug 6 from the base plate during ignition can be avoided.
The additional material at the rear 12 offers the advantage of a
greater connecting surface for the metal pin 4.5 to be grounded.
Further this increases the strength of the glass seal of the metal
pin in case of pressure impact on the front.
[0042] FIGS. 4 and 5 illustrate two further implementations of a
metal fixing material bushing 1.4 and 1.5 as per the invention with
slot 11.4 and 11.5. With these implementations the slot 11 can be
subdivided into three sub-areas. In the case of the implementation
as per FIG. 4 in the sub-areas 20, 21, 22, whereby the first and
third sub-areas 20 and 22 are preferably characterized by the same
diameter d.sub.20 and d.sub.22. The second sub-area 21 is
characterized by a lesser diameter d.sub.21 than diameters d.sub.20
and d.sub.22 and forms therewith a projection 23. Said projection
forms the undercut 36.4 arranged between the front and rear for
prevention of relative motion of the glass plug 6.4 in the
direction of the rear 12.4 towards the inner circumference 15.4 of
the slot 11.4. In particular the surfaces 24 and 25 directed toward
the front 13.1 and rear 12.2 form the stop faces for the glass plug
6.4 in axial direction. This implementation is characterized by a
fixing of the glass plug 6.4 in both directions, so that this
development is suitable in particularly advantageous fashion for
being randomly incorporable and positionable, particularly with
regard to the connection of the metal pins 4.4.
[0043] This also holds true in analogy for the development of the
metal fixing material bushing 1.5 presented in FIG. 5, in
particular of the base plate 3.5. This development can also be
subdivided into at least three sub-areas, whereby these individual
sub-areas, which are marked here as 20.5, 21.5 and 22.5, describe a
recess 26, which is arranged between the rear and front 12.5 and
13.5 respectively. The two outer sub-areas--first sub-area 20.5 and
third sub-area 22.5-- form in the process projections 27 and 28.
The surfaces 29 and 30 of the individual projections 27 and 28
pointing at each other in the process form a stop for the cooled
glass plug 6.5 in shifting between rear 12.5 and front 13.5. Both
implementations cause an increase of the required hydrostatic
forces in order to set the glass plug 6 in motion under shearing of
parts of them in the case of pressure load.
[0044] With all of the solutions described up to now it is possible
to use a narrower base plate 3 in comparison to the known solutions
from the state of the art with equal or increased strength of the
seal caused by the glass plug 6.
[0045] The production of the base plate 3.4 as per FIG. 4 occurs by
means of punching of the base plate 3' with a slot 11' with
constant diameter. The projection is achieved by means of two-sided
stamping with a predefined stamp depth and a stamping tool with a
greater diameter than the existing diameter of the slot 11' after
the punching. On the basis of the increase of the surface tension
of the material on the base plate 3' under the influence of the
stamping tool in the case of the exceeding of the flow limit a flow
of the material occurs, which then forms the projection 23. In the
process it is irrelevant whether the stamping operation takes place
first from the front or rear of the base plate.
[0046] In case a symmetrical design is desired, the stamping forces
and the stamp depth should however be selected equally for both
sides. The effected implementations apply in analogy also for the
formation of the base plate as per FIG. 5. Here, too in the first
processing step a punching out of the outer geometry of the base
plate 3.5' with slot 11.5' occurs. The two projections 27 and 28 in
the area of the front and rear 12 and 13 are then formed by means
of the pressure forces becoming active on the front and rears 12,
13 on the base plate 3.5'. In the process the represented form of
the recess is idealized.
[0047] If FIGS. 4 and 5 illustrate measures on the base plate 3.4
or 3.5, in particular the slots 11.4 and 11.5 for prevention of a
relative motion of the glass plug 6 toward them, FIGS. 6 and 7 show
measures on the metal pin 4.6 or 4.7 which serve to prevent the of
the metal pin 4.6 or 4.7 out of the glass plug 6.6 or 6.7 during
the test and further during the ignition operation. FIG. 6
represents a combination of the implementation presented in FIG. 1
with additional modification of the metal pin 4.6. The pin 4.6 has
at least one projection in the coupling area with base plate 3.6,
said projection is marked 31 and extends in circumferential
direction around the outer circumference 32 of the pin 4.6. In the
presented implementation it is a matter of a projection 31, which
extends around the entire outer circumference 32 of the metal pin
4.6. This projection can be formed by means of compressing or
squeezing of the metal pin 4.6. Another possibility not shown here
contains the arrangement of several projections adjacent to each
other in circumferential direction, preferably arranged adjacent to
each other at an equal distance on the metal pin 4.6 in the area of
the coupling n the base plate 3.6. The feature of projections on
the metal pin 4.6 contributes considerably to the improvement of
the strength of the connection. This feature prevents the removal
of the metal pin 4.6 during a corresponding test, in which normally
the metal pin fails with tensile stress and removal of the glass
plug. This holds true in analogy for the development as per FIG. 7.
With this development, the metal pin 4.7 has in the contact area
with the molten glass a number of projections arranged from above
the axial extent of the slot, which are connected in series. In the
simplest case a fluting 33 is used. With this fluting the same
effect can be achieved as described in FIG. 6. The remaining
structure matches that described in FIG. 6, which is why the same
reference symbols are used for the same elements.
[0048] The implementations described in FIGS. 6 and 7 can
additionally also be combined with the measures presented in FIGS.
2 through 5 on the base plate, in particular the slots.
[0049] FIG. 8 described a development in which the slot 11.8 is
with the same diameter over the entire extent between rear 12 and
front 13, whereby in the area of the rear 12.8 the base plate 3.8
is exposed to a stamping process. This takes place by means of
pressurization on the rear 12.8, whereby this pressurization is
performed punctually in the area of the circumference of the slot
11.8. The pressure impact follows the pressure execution on the
rear 12.8. As a result, projections aligned in conformity with the
metal pin 4.8 form over the entire area of the circumference of the
slot 11, said projections having critical influence on the pressure
ratios in the slot 11 from the front 13.8 to the rear 12.8. In the
presented case the projections 37.81, 37.82 arranged in
circumferential direction to each other at equal distance are
produced. The glass plug 6.8 can be here as a pressed piece.
[0050] FIG. 9 illustrates an implementation in which the inner
circumference 15.8 of the slot 11.8 is characterized by an
essentially constant mean diameter d.sub.1 and additionally for
achieving the holding effect for the glass plug 6.8, either the
inner circumference 15.8 of the slot 11.8 in the base plate 6.8 or
the outer circumference of the glass plug 6.9 undergoes surface
treatment, in particular a surface machining processing, such as
e.g. sandblasting or staining. In the process roughness values in
the area of .mu..gtoreq.10 .mu.m are achieved. The roughening of
the surface serves the purpose of fit and supports the strength. In
the implementation shown in FIG. 9 preferably the entire inner
circumference 15 of the slot 11.5 is subjected to a corresponding
surface treatment. Further the possibility exists to restrict the
surface treatment to only a sub-area, whereby this should extend at
least in the area of the rear 12.9.
[0051] In addition it would be possible to have the glass plug
which is inserted into the base plate to be additionally enclosed
by a socket. Then both the surface of the slot and/or the socket
and/or the metal pin can be roughened.
[0052] FIG. 10 illustrates a further alternative development. In
this development the slot 11.9 is characterized by a greater
diameter d.sub.2 in the area of the rear 12.9 than on the front
13.9. This implementation makes it possible to design slots 11.9
also in thicker base plates 3.9. The slot 11.10 is for example
punched or only bored out in sub-area 45.10. The second sub-area
48.10 is for example formed in both embodiments by boring this
sub-area 46.10. In the bored sub-area 46.10 the glass plug 6.10 is
inserted with the metal pin 4.10 and supported. Generally all of
the possibilities named in the description for FIGS. 1 through 9
for inserting at least one slot in particular by means of punching
out in a base plate are also suitable for inserting this slot in a
first sub-area of the base plate and the rough working of the
second sub-area for example by boring out of the base plate. The
glass plug 6 with the metal pin can then be inserted into the first
or second sub-area as described in FIGS. 1 through 9. While the
previously described exemplified embodiments all referred to metal
fixing material bushings, which comprised two metal pins, which
were preferably in parallel arrangement, of which one of the metal
pins was grounded to the rear of the base plate, the invention can
in principle also be applied with more than two metal pins and with
so-called mono pins. Mono pins are ignition units which comprise
only a single metal pin, which is held by a pin support. The pin
itself comprises for example a metal ring which forms the ground
connection.
[0053] Such a mono pin is shown in FIG. 11. The pin support 100
comprises a metal pin 103, which is embedded in an insulated panel
104, which is preferably made of glass. The pin support comprises a
base plate 101.1, which recesses the metal pin 103 as well as a
socket 101.2 with an inner wall panel 101.2.1. The end of the
sealed part of the metal pin 103 is electrically connected to the
base plate 101.1 by means of a bridge 105. The slot 106 is placed
in the base plate for example by means of a punching step. The slot
can be placed in the base plate as previously described in FIGS. 1
through 10. Together with the slot the base plate 101.1 can be
punched out as previously described. Preferably the slot is punched
out together with the base plate. Especially preferably the base
plate forms a one-piece component with the socket 101.2. The
manufacturing of a one-piece component can for example happen by
having a punch part punched out in one procedure step and the
socket can be obtained by means of deep drawing.
[0054] Preferably the inner wall panel of the socket as well as the
free end of the metal pin 103 is coated. Gold for example is used
as a coating material. Preferably the coating is applied using
electrolytic procedures. The coating serves the purpose of keeping
the electrical resistance at the junction point 108 between a plug
120, which is inserted into the socket and of the interior 101.1.2
of the socket 101.2 low. The plug is designated as 120 in the
figure.
[0055] In the case of all of the implementations presented in FIGS.
1 through 10 the base plate 3 executed as a swivel part in
implementations as per the state of the art is replaced by stamped
metal parts. The individual measures for prevention of a withdrawal
of the metal pin 4 from the base plate under stress, which were
provided in the individual figures on base plate 3 and for
prevention of the withdrawal of the metal pin from the fixing
material on the metal pin can also be used with each other in
combination. In this regard the implementation is not subject to
any restrictions at all. However, those implementations are aimed
at that guarantee a high strength of the overall connection between
the metal pin 4 and the base plate 3 and thus the metal fixing
material bushing 1.
[0056] With all of the implementations presented in the figures the
slots can be formed with variable cross section. Preferably however
circular cross sections are selected. The formation of the
undercuts takes place as an integral component of the base
plate.
List of Reference Symbols
[0057] 1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 Metal fixing
material bushing
[0058] 2 Metal collar
[0059] 3, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9 Base plate
[0060] 3', 3.2' Base plate as semi-finished product during
production
[0061] 4, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9 Metal pin
[0062] 5 Metal pin
[0063] 6, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9 Glass plug
[0064] 7 First face
[0065] 8 Second face
[0066] 9 Punched element
[0067] 10 Outer circumference
[0068] 11, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.9 Slot
[0069] 11', 11.2' Slot during production
[0070] 12, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8, 12.9 Rear
[0071] 13, 13.2, 13.3, 13.4, 13.5, 13.6, 13.7, 13.8, 13.9 Front
[0072] 14 Outer circumference
[0073] 15 Inner circumference
[0074] 16 First sub-area
[0075] 17 Second sub-area
[0076] 19 Connecting surface
[0077] 20, 20.5 First sub-area
[0078] 21, 21.5 Second sub-area
[0079] 22, 22.5 third sub-area
[0080] 23 Projection
[0081] 24 Surface
[0082] 25 Surface
[0083] 26 Recess
[0084] 27 Projection
[0085] 28 Projection
[0086] 29 Surface
[0087] 30 Surface
[0088] 31 Projection
[0089] 32 Recess
[0090] 33 Opening
[0091] 34 Fixing material
[0092] Material for prevention of a relative motion between fixing
material and inner circumference of the slot
[0093] 36, 36.2, 36.3, 36.4, 36.5, 36.6, 36.7, 36.8 Undercut
[0094] 37, 37.3, 37.4, 37.5, 37.6, 37.7, 37.81, 37.82
Projection
[0095] 38 Sheet metal
[0096] 39 Punching tool
[0097] 40 Die
[0098] 41 Punch
[0099] 42 Stamping tool
[0100] 43 Stamping tool
[0101] 44 Die
[0102] 45 First sub-area
[0103] 46 Second sub-area
[0104] 100 Pin support
[0105] 101.1 Base plate
[0106] 101.2 Socket of the base plate
[0107] 101.2.1 Inner wall panel of socket
[0108] 103 Metal pin
[0109] 105 Bridge
[0110] 106 Slot
[0111] 108 Junction point
[0112] 120 Plug which is inserted into the socket
[0113] d.sub.1, d.sub.3 Diameter
[0114] d.sub.2, d.sub.2.3 Diameter
[0115] l.sub.d1 Length
[0116] l.sub.d2 Length
[0117] l.sub.d1.3 Length
[0118] l.sub.d2.3 Length
* * * * *