Note: Descriptions are shown in the official language in which they were submitted.
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A METHOD OF PRODUCING AN ELECTRIC OR ELECTRONIC COMPONENT, A METHOD
OF PRODUCING A KEY AND A K~Y
The present invention relates to the technical field of production of
electric or electronic components, particularly the production of
keyboard switches and such keyboard switches.
Uithin the above technical field, numerous methods of producing
electric or electronlc components are known as well as numerous
keyboard switches. Reference Ls made to the following patent
specifications: EP 0030473, DE 2740746, DE 3542953, DE 3545798, EP
0164799, SE 440836, US 4331851, US 4690484 (corresponding to
DE 3542953), US 4659881, US 4352964, and US 4102039.
An object of the present invention ls to provide a method rendering
it possible to produce a keyboard switch in a few and simple
production steps from a few componenes.
A further obJect of the present invention is to provide a novel
technique of producing a keyboart switch, which may be used in
accordance w$th so-called SMT-technique (SMT: Suriace Mounting
Technique), i.e. which may stand exposure to solder metal material,
such as tin heated to a temperature of e.g. 240C, for approx. 60
sec.
A still further ob~ect of the present invention is to provide a novel
tschnique of producing a keyboard switch, produced in a sequential
proces~ and tested prior to its delivery from the production line.
A still further obJect of the present invention is to provide a
keyboard switch and to provide a method of producing ~uch keyboard
switch, which keyboard switch is of a compact, modular structure
which allows the keyboard switch to be used in connection with
accessory components, such as modular display units, keyboard pads,
etc.
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The above and other objects and advantages obtained in accordance
with the teachings of the prPsent invention will be evident from the
description below.
Thus, in accordance with a first aspect of the present invention, a
S method of producing a keyboard switch, said keyboard switch
comprising:
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a housing of an insulating material having outer side ~alls,
a switching element enclosed in said housing, and
at leàst two metallic terminal components, each including:
an outer terminal extending outwards from an outer side
wall of said housing and defining an outer terminal end,
and an electric contact means being enclosed in said
housing and integrally connected to said outer terminal at : :
an end thereof opposite to said outer terminal end; ~
.
said switching element being switchable between a first state in
which said switching element is out of electrically conductive
contact with at least one of said electric contact means of said ac
least tws metallic terminal components, and a second state in which
said switching element is establishing electrically conductive :
contact between said electric contact means of said at least two
metallic components;
the method comprising the following sequence of steps:
(a) providing a continuous track of the metal of said metallic ~
terminal components,
(b) processing said continuous track so as to for~ said metallic
terminal components and a carrier strip, said metallic terminal
components being integrally connected to saLd carrier strip
through said outer terminal ends,
(c) casting a base housing component of said insulating msterial
around said metallic terminal components, said base housing
componene tefining outer side walls constituting at least par~
of said outer side walls of said housing through which outer ~:.
slde walls of said base housing component said outer terminals ~ ~
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extend, said base housing component comprising a~ least one eag
protruding outwards from an outer side wall of said base housing
component and being cast to said carrier serip for establishing
mechanical connection between said base housing component and
said carrier strip, said base housing component further havin~ a
recess in which said electric contact means are exposed,
(d) arranging said switching element in said recess of said baise
housing component so as to be switchable between said first and
second states,
(e) providing a top housing component having an aperture,
(f) providing a stem means,
(g) arranging said stem means in said aperture of said top housin~
component and arranging said top housing component relative tO
said base housing component together constituting said housing,
said stem means being arranged relative to said switching
element so as to switch said switching element between said
first and said second states by actuation,
(h) separating said metallic terminal components from said carrier
strip by separating said outer terminals from said carrier strip
at said outer terminal ends,
ti) te5tin8 said keyboard switch produced in steps (a)-(h) in a test
stand, while said base housing component is mechanically
connected to said carrier strip through said tag, by actuating
said stom means in order to test if said switching element is
switchable between said first and second states, and by
determining whether said at least two metallic terminal
components are electrically insulated relative to one another or
not insulated relative to one another when said switching
element is in said first state and further determining whether
said at least two metallic terminal components are in -~
electrically conductive connection with one another or not when : .
said switch element is in said second state, and
(~) provided said keyboard switch is identified in step (i) as a
properly working component, separating said t~g from said base -
housing component.
In accordance with the method according to the presen~ invention, the
keyboard switch is manufactured from only five components, viz. ~he
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continuous track, the base housing component, the switching element,
the stem msans, and the top housing component. Since the base housing
component is mechanically connected to the carrier strip through the
tag, the keyboard switch is, during its manufacturing process,
S advanced through a number of production stations corresponding to the
above steps by moving the carrier strlp. In accordance with a
particular feature of the above method accordinfef to the present
invention, the keyboard switch is very easily tested in the above -
step (i) as the keyboard switch produced in the above steps (a)-(h)
is simply presented to the test stand integrally connected to the
carrier strip through the tag.
In accordance with a preferred embodiment of the method according to
the present Lnvention, two carrier strips are processed in the above
step (b) from said continuous track, between which carrier strips
said metallic components are arranged having their outer terminal
ends integrally connected to said carrier strips through said outer
terminal ends, and two tags are further cast in the above step (c) tO
a respective carrier strip. By the provision of two carrier strips
and two tags cast to a respective carrier strip, the keyboard switch
is to a high degree mechanically supported in its fixation to the rwo
carrier strips when the keyboard switch is advanced through the above
steps. :
A further increase in the mechanical fixation and support of the
keyboard switch when advanced through the above steps, is obtained in
accordancff2 with an alternative of the above preferred embodiment of
the method according to the present invention in that each metallic
terminal component conseitutes a link between said two carrier :;
strips, and each of said metallic components haff~ two outer terminals
defining outer terminal ends integrally connected to a respective
carrier strip.
In accordance with the presently preferred embodiment of the method
according to the present invention, said switching elemen~ is a domed
metal disc, which disc in step (d) i9 arranged with its doms
protruding outwards from said recess, ant which disc in its normally
35 domed shape ic in said first state and ic deformable from said do~ed ~-
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shape into a deflected shape constituting said second state, and
said stem means provided in step (f) and arranged in said aperture of
said top housing component in step (g) is actuatably acting on said
metal disc for deforming it from said domed shape to said deflected
shape by activation.
In step (g), an elastically compressible body means is preferably
arranged in accordance with the method according to the present
invention between said stem means and said metal disc in step (f),
and, as will be explained below, the elastically compressible body
means serves more purposes, viz. to lncrease the travel or stroke of
the metal disc when deformed and optionally to protect the metal disc
by sealing along the circumferential edge of the disc and
consequently protecting the metal disc and the electric contace means
from corrosive gases and exposure to high temperatures in a surface
mounting process, when the keyboard switch is soldered to a
supporting circuit board, e.g. in a wave soldering machine.
It has been realised that a domed metal disc produces an unpleasant
and harsh click, when it is deformed. In accordance with a particular
aspect of the present invention, it has further been realised that
the click may be damped resulting in a more pleasant sound by
providing an acoustically damping material coating or layer on the
one side surface of the domed metal disc, which side surface
constitutes the outer or convex side surface of the domed metal disc.
Consequently, in accordance with a further embodiment of the method
according to thei present invention, the metal disc is preferably
punched from a metal foil, which is provided with a coating of an
acoustically damping material on one side surface, which side surface
in said domed metal dlsc constitutes the outer or convex side surface
of said domed metal disc.
Furthermore, the keyboard switch produced in accordance with the
method according to the present invention is preferably a keyboard
switch which may stand exposure to elevated temperatures, such as
240aC, during e.g. 60 sec, e.g. in a surface mounting process, e.g.
in a wave soldering machine, as the base and top housing componencs
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of the keyboard switch are preferably cast from a hlgh-temperature
resistant plastics material.
In accordance wieh a second aspect of the present in~ention, a `
keyboard switch is pro~ided, which keyboard switch comprises:
a housing of an insulating material having outer side walls,
a domed metal disc enclosed ln sald housing, and
at least two metallic terminal components, each including:
an outer terminal extending outwards from an outer side
wall of said houslng and defining an outer terminal end,
and an electric contact means being enclosed in said
housing and integrally connected to said outer terminal ae :
an end thereof opposite to said outer terminal end;
said domed metal disc being switchable between a first state in
which said domed metal disc is in ies normally domed shape and is out . :
of electrically conductive contact with ae least one of said electric
contact means of said at least two metallic terminal components, and :
a second state in which said domed metal disc is in a deilected shape
and establishes electrically conductive contact between said electric :
contact means of said at least two metallic components by deforming
said disc from its normally domed shape to a deflected shape;
said housing comprising:
a base housing component of said insulating material cast around
said metallic terminal components, and
a top housing component having an aperture and a stem means,
.:
sait base housing component defining outer side walls constituting at
least part of said outer side walls of said housing through which ;
outer side walls of said base housing component sa~d outer terminals
extend, said base housing component further having a recess in which ;
said electric contact means are exposed, said domed met~l disc being
arranged in said recess of said base housing component with its dome
protruding outwards from said recess so as to be switchable between
said first and second states,
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said stem means being arranged in said aperture of said tOp housin~
component and being arranged relative to said domed metal dLsc so as
to switch said domed metal disc between said first and said second
states by actuation, and
said metal disc being made from a metal foil, which is coated with an
acoustically damping material on one side surface constituting the
outer or convex side sùrface of said domed metal disc.
As explained above, the keyboard switch according to the present
invention preferably further comprises an elastically compressible
body means arranged between the stem means and the metal disc, which
body means constitutes a means for increasing the stroke of the metal
disc to a larger stroke of the stem means.
In the preferred embodiment of the keyboard switch according to the
present invention, the keyboard switch is a keyboard switch which
may stand exposure to high temperatures, such as 240C, for e.g. 60
sec, as the keyboard switch is exposed to e.g. so~der in a surface
mounting process. The base and top housing components are made from a
high temperature resistant plastics material, such as high-crystal-
line copolymers, epoxy resins, olefin-carbon-monoxide copolymers,
polycarbonates, polyolefin sulphonates, e.g. polyethylene
sulphonate, PES, or polyethylene-terephthalates, e.g. PETP or PET.
In order to seal the domed metal disc and consequently protect the
domed metal disc against exposure to gases, such as corrosive gases,
and to elevated temperatures, e.g. in the above ment$oned surface
mounting process, the keyboard switch according to the present
invention may further have its stem means, body means and domed metal
disc arran&0d coaxially relative to each other, and the elastically -
compressible body means may preferably comprise a circular membrane
part having a circu~ferential bead and a central stem part, said stem
part of said body means constituting an elastically compressible part
for the transmission of the actuation of said stem means to said
domed metal disc, which domed metal disc is preferably arranged
within the circumferential bead of the membrane part so as to have
said bead seal along the circumferential edge of the domed meeal disc
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and consequently seal the domed metal disc relative to the environment.
In the above described preferred embodiment of the keyboard switch, the elastically
compressible body means is advantageously made from silicon rubber, and the domed
S metal disc is advantageously made from a CuBe foil of ~ thickness of e.g. 0.075mm.
Embodiments of the present imention will now be further described by way of
exarnple only with reference to the drawings, in which:
Fig. 1 is a schematical and perspective view of a production line in which a ke~board
switch is produced in accordance with the present method.
Fig. 2 is a partly vertical sectional view of the keyboard switch shown in Fig. 1.
Fig. 3 is a schematical and perspective view illustrating the production of an
accessory component of the keyboard stich sh~hvn in Figs. 1 and 2 in accordance with
the present method.
Fig. 4 is a schematical, perspective and partly aploded vlew of a combination of a
keyboard switch, and an accessory component including two light emitting diodes and
produced in accordance with the present method, and a manually operable keyboardswitch housing component,
Fig. 5 is a schematical, perspective and partly exploded view of the combinationsh~wn in Fig. 4, turned upside down, and
Fig. 6 is a schematical and perspective view of a combination of a keyboard switch
emitting diode support constituting an accessory top housing component of the key.
In Fig. 1, a method of producing a keyboard switch is illustrated comprising five
individual production steps schematically illustrated by positions designated the
reference numerals 1-5,
In position 1, a metal plate is provided constituting a continuous track of a metal foil
10.
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In position 2, the metal foil track 10 is machined in a punching
tool, not shown in Fig. 1, and processed into two carrier strips 11
and 12 between which two termina1 assemblies 13 ant 14 extend. As
will be evident from the description below, each of the terminal
assemblies 13 and 14 is in a subsequent production step machined into
two terminals. Thus, the terminal assemblies 13 and 14 are integrally
connected to the carrier strips 11 and 12 through ends of the
terminal assemblies, which ends are intended to constitute the outer
terminal ends of the above mentioned terminals. As is evident from
Fig. 1, the terminal assembly 13 is machined into a shape defining a
centrally indented bar 15, from which a contact bar 17 extends
towards the adjacent terminal assembly 14. The outer end of the
contact bar 17 remote from the indented bar 15 is further machined
into a domed contact pad 19. As is also evident from Fig. 1, the
terminal assembly 14 is also machined into a shape defining a
centrally indented part 16, from which two connector bars 18 extend
towards the adjacent terminal assembly 13. The contact bars 13 are
further provided with raised, outer contact parts 20.
In position 3, a base housing component 22 is cast around the above
described components 15-20 of the terminal assemblies 13 and 14. The
base housing component 22 is cast with 8 central recess 23 defining a
circumferential inner surface 24 and a bottom surface 25, in which
the contact pad 19 and the raised, outer contact parts 20 are exposed ~ -~
and protrude upward~. The base housing component 22 further defines a
top surface 26, a bottom surface, not shown in Fig. 1, a first outer
side surface 27, which faces the carrier strip 12, and a second outer
side surface 28. The surfaces 26, 27 and 28 are perpendicular to each
other. The base housing component 22 further has a botto~ surface,
not shown in Fig. 1, parallel with the top surface 26, and two outer
side surfaces, not shown in Fig. 1, parallel with the first and a
second outer side surfaces 27 and 28, respectively. From the firs~
outer side surface 27 and further from the outer side surface not
shown in Fig. 1 parallel therewith carrier ~ags 29 protrude. The
carrier tags 29 are cast integrally with the base housing component
22 and are cast to the respective carrier strips 11 and 12.
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As is evident from Fig. 1, the base housing component 22 is further
at its top surface 26 and its outer side surfaces 27 and 28 provided
with indents mating with a top housin~ component 30 and accessory :
components to be described below, respectively.
In the above described base housing component 22, a domed metal disc
31 is arranged, which metal disc has its dome facing upwards, i.e.
outwards from the recess 23 of the base housing component 22. The
domed metal disc 31 is in its normally domed shap~ in contact wlth
the contact parts 20, however, out of contact with the central
contact pad 19,.~nd does consequently not in its normally domed shape
establish electrically conductive connection between the contact pad
19 and the outer contact parts 20 and further between the terminal
assemblies 14 and 13. The domed metal disc 31 is at its upper or
convex side surface provided with a central coat$ng 32 of an
acoustically damping material, e.g. of sillcone, serving the purpose
of altering the unpleasant and harsh noise ~enerated by an undamped
domed metal disc, when the metal disc is deformed from its domed
shape to a deformed shape and vice versa into a more pleasant, damped
noise. On top of the domed metal diso 31, a rubber component 33 is
arranged, which comprises two integrally connected parts, a membrane
part 34 and a stem part 35. The membrane part 34 has, as is evident
from Fig. 1, a larger outer diametre than the domed metal disc 31 and
is further at its lower sLde surface, shown in Fig. 2, provided with
a circumferential bead 36. The bead 36 serves the purpose of sealln~
along the outer circumferential edge of the domed metal disc 31.
The stem part 35 is a hollow part, which is elastically deformable
and cerves the purpose of transmitting a mechanical force from a
button 37 to which said mechanical force is applied to the domed
metal disc and further the purpose of increasing the stroke of travel
of the button 37 relative to the stroke of travel of the domed metal
disc, as the metal disc is deform~d or allowed to revort to its
normally domed shape from its deformed shape, by the elaseic
deformation of the stem part 35.
As is evident from Fig. 2, the membrane part 34 is at its lower slds
surface provided with a protruding part 38 serving the purpose of
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contacting the central part of the domed metal disc 31, when the stem
part 35 is actuated and forced downwards by the button 37. As the
domed metal disc 31 and the rubber component 33 are arran~ed ln the
recess 23 of the base housing component 22, the top housing component
30 is, with the button 37 arranged in a central aperture oi the top
housing component 30, arranged on top of the base housing component
22 and fixed thereto. The top housing component 30 is, as is evident
from fig. 1, pro~ided with a central cylindrical bottom part fitting
into the recess 23 in a snap fitting, as iq e~ident from Fig. 2, and
further provided with downwards protrud~ng fins for co-operating with
the above mentioned indents of the top surface 26 of the base housing
component 22. The travel of the button 37 within the aperture 39 of
the top housing component 30 is controlled by fins 40 protruding : -
outwards from the circumferential outer side surface of the button 37
at the lower edge thereof, as is evident from Fig. 1, which fins 40
are adapted to co-operate with indents of the inner wall of the
aperture 39 of the top housing component 30. -
In position 4 of Fig. 1, the above described keyboard switch assembly
is assembled from the base housing component 22, the top housing
20 component 30, ~he button 37, the domed metal disc 31, and the rubber
component 33 enclosed in the housing of the keyboard switch assembly.
From the first outer side surface 27 and the opposite, parallel side
surface, the terminal assemblies 13 and 14 protrude. As the keyboard
switch assembly leaves position 4, the terminal assemblies 13 and 14
are separated from the carrier strips 11 and 12 at the outer ends
thereof. Consequently, the keyboard switch assembly is connected to
the carrier strips 11 and 12 through the tags 29, exclusively. As the
keyboard switch assembly leaves posit~on 4, the outer terminals ~
defined by the parts of the terminal assemblies 13 and 14 extending ~.
outwards from the base housing component 22 are, furthermore, bene
downwards, as is evident from the keyboard switch assembly disclosed
in position 5 of Fig. 1. By the separation of the terminal assemblies
13 and 14 fro~ the carrier strips 11 and 12, the short circuiting
connection between the terminal asse~blieq 13 and 14 ~hrou~h the
carrier ~trips 11 and 12 is eliminated.
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When still mechanically supported by the carrier strips 11 and 12 through the tags 29
connecting the base housing component 22 to the carrier strips ll and 12 the
keyboard switch assembly may in position S be tested in an automated electric test
stand. The test stand is illustrated schematically by a test block 41, which is maved
from the position shown in Fig. I upwards so as to receive the outer ends of theterrninals defined by the terminal assemblies 13 and 14 in apertures 42 of the block
41. In the apertures 42, metal contact means are provided for establishing electrically
conductive contact to the terminals 13 and 14 and are conneceed to a test circuit, not
shown in Fig. 1, which is capable of determining the presence or absence of a short-
circuiting condition. By further actuating the button 37 and consequently deforming
the domed metal disc 31 from its normally domed shape into its deformed shape bythe interaction of the rubber component 33 and still monitoring the presence or
absence of a short-circuiting condition between the terminals 13 and 14, the keyboard
switch assembly is easily tested. The object is to determine if the keyboard switch
assembly is a properly functioning keyboard switch, which in its unactuated state does
not establish electrically conductive connection between the terrninals 13 and the
terminals 14, and which in its actuated st~te establishes electrically conductive
connection between the terminals 13 and 14. Provided the keyboard switch assembly
has been identified as a properly working keyboard switch assembly, it is separated
from the carrier strips 11 and 12 by cutting or breaking the keyboard switch assembly
loose from the tags 29.
In Fig. 1, the carrier strips 11 and 12 are provided with through-going holes 43 and
44. The above described process of producing a keyboard switch assembly is
indicated above and carried out by moving the track 10 from position 1 to position
S by well-l~own computer controlled mechanical advancing means. The holes 43
and 44 consequently serve the purpose of co-operating with gripping means for
advancing the track 10 and further, or alternatively, with e.g. optical or proximity
detector means to inforrn the process controlling computer about the position of the
track or the carrier strips 11 and 12
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relative to an intended position in one of the positions 1-5 shown in
Fig. 1.
In Fig. 2 a vertical sectional view of ehe keyboard switch assembly
described above is shown disclosing the above described components
and further in greater detail the sealing of the domed metal disc 31
relative to the environment by the bead 36 of the membrane part 34 of
the rubber component 33. . .
In 8 production line for the produceion of the keyboard switch
described above with reference to Fig. 1, the metal plate 10 from
which the keyboard switch is produced may be advanced through a
number of processing stations. Alternatlvely, the metal plate 10 may
be stationary and the production stations may be moved in relation to
the metal plate. Furthermore, the production line may constitute any
appropriate combination of the above possibilities, viz. the
advancing of the metal plate 10 in relation to the stations and the
movement of the stations in relation to the metal plate. However, a
very important aspect of the present invention is the permanent
fixation of the keyboard switch n relation to the metal plate 10 or
to the carrier strips 11 and 12 untll the keyboard switch has been
tested and positively identified as a properly functioning key. Thus,
the keyboard switch is not to be transferred from its production line
to a test stand as the keyboard switch is permanently fixed to the :
carrier strips 11 and 12 and consequenely in a fixed position in
relation to the tools of the individual stations 2-S, pareicularly in
a fixed position in relation to the block 41 constituting part of a
test stand shown in position S of Fig. 1.
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As mentioned above, the keyboard switch assembly described with
reference to Figs. 1 and 2 is adapted to co-operate with accessory
components, such as a display assembly 50 shown in Fig. 4. The
display assembly 50 is in Fig. 4 mechanically connected to a keyboard
switch assenbly according to the present invention, which keyboard
switch assembly is designated the reference nu~ral 48 In its
entirety, through outwardly protruding dovetail shaped locking ~eans
co-operating with the above mentioned indents of the outer sid~
surface 28 shown in Fig. 1. By these in~arlocking doveeail shaped
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14 l 3 2 q 4 l ~1
~ale and female locking means, the display assembly 50 is connected
and mechanically fixed to the keyboard switch assembly 48. The
~eyboard switch assembly 48 differs from the keyboard switch assembly
described with reference to Figs. 1 and 2 in that the button 37 is
substituted by a button 47 and in that the top housing component 30
is substituted by a top housing component 60, the top surface of
which is at the same level as the button 47.
The display assembly 50 comprises two light emitting diodes 51 and
52, which are received in the housing of the display assembly 50 and
connected to terminals thereof, which terminals are designated the
reference numerals 113 and 114 and, like the terminals 13 and 14 of
the keyboard switch assembly 48, of a configuration allowing the
mounting of the keyboard switch assembly 48 and the display assembly
50 in a surface mounting process, which terminals are known in the
art as terminal type "J" SMD. Obviously, the accessory assembly 50
may comprise alternative components. Thus, the two light emitting
diodes 51 and 52 only constitute examples of components of the
display assembly 50 and may in an alternative embodiment be replaced
by e.g. a single light emitting diode, one or more incandescent lamps :
etc. Furthermore or alternatively, the accessory assembly 50 may
comprise one or more active or passive components, such as an
integrated circuit, a transistor, a resistor, a capacitor, or a
relay. Apart from the accessory component or display assembly 50, ehe
keyboard switch assembly 48 co-operates in Fig. 4 with a push button
assembly 54, which comprises two parts, viz. a fixed housing part 55,
which is mounted and fixed relative to the asse~blies 48 and 50, and
a movable or pivotable part 56. The top housing componene 60 also
differs from the above described top housin~ component 30 shown in
Figs. 1 and 2 in that the top housing component 60 is provided with a
further component 61 defining an outer groove 62 for co-operating
with an axial part of the pivotable part 56 of the push button
assembly 54.
In Fig, S, the above assemblies 48, S0 and 54 are shown turned up~ide
down. Thus, in Fig. 5 the above ~entioned axial part co-operating
with the groove 62 is shown designatsd the reference numeral 63. In
Fig. 5, two protruding parts 64 of the fixed housing part 55 of ~he
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push button assembly 54 is further shown serving the purpose of cooperating with the
indents mentioned above with reference to Fig. 1 of the outer side surface 27 and
further of the opposite outer side surface of the base housing component 22. Thefixed housing part 55 is further provided with snap-locking means 6~ serving theS purpose of gripping around the keyboard switch assembly 48 and fixing the housing
part 55 thereto. As is evident from Fig. 5, the housing part 55 is further provided
with two protruding journalling means 67 cooperatir~ with mating journalling means
68 of the pivotable part 56 of the push button assembly 54, which is further pr~vided
with a protruding stem means 66 for transferring a mechanical pressure applied to the
pivotable part 56 to the push button 47 and further to the internal contact element of
the keyboard switch constituted by the domed metal disc 31, shown in Figs. 1 and2.
The keyboard switch assembly 48 and the display assembly 50 sh~7wn in Fig. 5,
however, differ from the keyboard switch assembly 48 and the display assembly 50shown in Fig. 4 in that the terminals 13, 14 and 113, 114 are of a different
configuration, viz. the SMD terminal configuration known in the art as "Gull ~Ing".
In Fig. 3, three positions 6, 7 and 8 of the sequential process of producing thecomponent or display assembly 50 described above with reference to Figs. 4 and 3are shown. From a metal track similar to the above described metal track 10 shawn
in Fig. 1, two carrier strips 111 and 112 are punched and brought to the first position
designated 6 in Fig. 3. As is evident from Fig. 3, tw~ terminal assemblies 113 ad
114 are further punched from the above mentioned metal track. The terminal
assemblies 113 and 114, however, diiffer from the terminal assemblies 13 and 14 -
sh~wn in Fig. 1 in that ~e terminal assemblies 113 and 114 do not constitute links
between the carrier strips 111 and 112. Thus, the terminal assembly 113 is connected
to the carrier strip 111, exclusively, whereas the teriminal assembly 114 is coMected -~
to the carrier strip 112, exclusively. In position 7, the terminal assemblies 113 and
114 are fiJrther processed and each separated into two individual termirtal assemblies.
Thus, the terminal assembly 113 is divided into two tenninal assemblies 113a and113b, while the
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terminal assembly 114 is separated into tu~ terrninal assemblies 114a and 114b. The
parts of ~e terminal assemblies 113a,b and 114a,b remote from the carrier strips 111
and 112, respectively, are further indented and bent into the shape shown in Fig. 3.
In position 8, a housir,g part 122 is cast around the terminals 113a,b and 114a,b.
After the casting step shown in position 8, the component constituting the housing of
the display assembly 50 shawn in Figs. 4 and 5 is separated from the carrier strips
111 and 112. As is evident from Fig. 3, the carrier strips 111 and 112 are provided
with through-going holes 143 corresponding to the holes 43 and 44 of the carrierstrips 11 and 12 shawn in Fig. 1.
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It is to be realized that the above described keyboard switch or keyboard switchassemb1y is of a modular configuration, as the keyboard switch assembly may co-
operate with an accessory component such as the above described display assemblyand the abo~e described push button assembly, which as will be evident to the skilled
art worker is translucent or is provided with a translucent part. Thus, the pivotable
part 56 of the push button 54 may advantageously be made from a translucent
material, which is illuminated by the light emittir~ diodes 51 and 52 of the display
assembly 50. Furtherrnore, as will be evident from the description of Fig. 4, the
push button or the top housing component of the keyboard switch assembly 48 may
be modiffed in order to meet special requirements.
In Fig. 6, a keyboard switch assembly is shown, which keyboard switch assembly is
modifled relative to the above described keyboard switch assembly 48 shown in Figs.
4 and 5, in that a push button extender 70is arranged on top of the push button 47
shown in Fig. 4, which push-button extender 70 is of a cylindrica1 configuration.
The push but~on extender 70 defines an inDer space 71, in which a light emittingdiode 72 is arranged, which diode is mounted in a soclcet 73 received in the inner
space 71. The light emitting diode 72 has its pins extending through slits 75 and 76
of the push butbon extender 70 and further through apertures of the top housing
component 60 of the keyboard switch assembly. In Fig. 6, one of the apertures ofthe top housing 60 of the
,.~,
1 32~ 4 1 ~1
17
keyboard switch assembly is designated the reference numeral 74. One
of the pins of the light emitting diode 72 is also shown in Flg. 6
and designated the reference numeral 77. In Fi~. 6, the terminals 13
and 14 of the keyboard switch assembly and further the pin 77 of the
light emitting diode 72 are of a configuration different from the
terminal configurations shown in Figs. 4 and 5. Thus, it is to be
realised that the terminals 13 and 14 and further any pins or
terminals of accessory components such as the pin 77 or the terminals
113 and 114 may be of any appropriate configuration.
EXAMPLE 1
In a prototype implementation of the method of producing the keyboard
switch assembly shown in Figs. 1 and 2, the carrier strips 11 and 12 ;
and the terminal assemblies 13 and 14 were mach~ned from 0.3 mm
silver-plated tin-bronze. The carrier strips 11 and 12 had a width of
3 mm, and the distance between the centre lines of the carrier strips
11 and 12 was 23.96 mm. The distance between the terminal assemblies
13 and 14 was 7.6 mm, the diametre of the holes 44 was 1.2 mm, which
holes were arranged at the centre lines of the carrier strips 11 and
12 and further at lntermediate positions relative to the terminal
20 assemblie~ 13 and 14, the diametre of the holes 43 was 1.8 mm. The -
width of the indented part 16 was 4.4 mm, the raised contact parts 20
were raised 0.5 mm relative to the indented part 16. The raised
contact parts 20 and the contact pad 19 were positioned centrally or
at the intermediato line of the terminal assemblies 13 and 14. The
25 contact pad 19 was raised 0.45 mm relative to the indented bar 15,
and was constituted by a dome with a radius of 1.35 mm defining a
circular contact pad of a diametre of 1.224 mm.
:
The base housing component 22, the top housing component 30 and the
button 37 were cast from polycarbonate (or In alternative
implementatlons from PES or PETP). The shrinkage of the components
was less than approx. 0.5 per cent. The push button 37 was of a
diametre of 6.5 mm and a height of 2.8 mm. The fins 40 had a hel6h~
of 0.8 mm, and oppositely positioned fins defined a maximum ou~er
dia~etre of 7.65 m~. The button 37 fureher had a centrsl, inwardly
~, .. . .
18
protruding part shown in Fig. 2, which part defined a height of o 95
mm from the lower side surface of the bottom.
The assembly comprising the base housing component 22 and the top
housing component 30 defined a hei~ht of 5 mm, while the maxim~m
height of the keyboard switch assembly from the lower side surface of
the base housing component 22 to the top surface of the keyboard
switch 37 was 6.4 mm. The outer dimensions of the bottom and top
housing parts were 10 mm x 10 mm.
The rubber component 33 was made from silicone rubber of a hardness
of 38 Shore +-2. The outer diametre of the membrane part 34 was 8.83
mm, the inner diametre defined within the bead 36 was 6.8 mm, the
thickness of the membrane part 34 was 0.3 mm, and the overall
thickness of the bead was 0.63 mm. The central protruding part 38
defined a circular surface of a diametre of 1.4 mm protruding 0.4 ~m
from the lower side surface of the membrane part 34. The stem part 35
was a hollow, cylindrical part of a height of 3.16 mm, which stem
part defined an upper outer diametre of 2.8 mm, an angle of taper of
the outer cylindrical side surface of the stem p~rt 35 of 7°, an
inner recess of a depth of 2.5 mm and of a inner diametre of 1 mm and
definin8 by its inner cylindrical surface an angle of taper of 5°
The domed metal disc 31 was msde from 0.075 mm copper beryllium
alloy. The outer diametre of the metal disc 31 was 6.4 mm and the
maximum diametre of the acoustically damping coating 32 was 5 mm. The
arch or dome radi~s of the disc was 39.1 mm, and the height of the
dome was 0.25 mm. The domed metal disc was deformed froo its normally
domsd shape by the application of a pressure of 155-165 g and
reverted from its deformed shape to lt~ normally domed shape when
the pressure applied to the domed metal dlsc was less than 115-125 g.
Together the rubber component 33 and the domed metal dlsc 31 provided
an lncrease of the stroke of the domed metal disc 31 of approximaeely
0.25 mm-0.3 mm to a total stroke or tra~el of the push button 37 of
approximately 0.8 mm-l mm.
1 3294 1 i
19
EXAMPLE 2
The accessory component or display assembly 50 shown in Fig. 4 was in
a prototype implementation made from a terminal plate constituted by
a silver-plated tin-bronze plate and a housing cast from
polycarbonate (or, alternatively, PES or PETP), like the keyboard
switch described above in example 1. ~ :
Although the invention has been described above with reference to
specific embodiments and implementations, it $s to be understood that
the present invention is not limited to the above embodiments and
implementations, thus, numerous modifications and amendments are
obvious to a person having ordinary skill in the art within the scope :.
of the present invention as defined in the appending claims.
. . ,:
