Behind-the-ear hearing aid and attachment module for same

Information

  • Patent Grant
  • 6831988
  • Patent Number
    6,831,988
  • Date Filed
    Monday, February 10, 2003
    21 years ago
  • Date Issued
    Tuesday, December 14, 2004
    19 years ago
Abstract
A hearing device has a shell, an electric/acoustic transducer, and electronics within the shell. One end of the shell constitutes the acoustic output to the ear and further includes a compartment at the other end of the shell. A module is removably introduced into the compartment and includes a battery and a voltage regulator. The voltage regulator has an input operationally connected to the battery and has an output in electric contact with the electronics.
Description




BACKGROUND OF THE INVENTION




Behind-the-ear hearing aids are known which comprise a curved, hook-shaped shell running substantially along an identically shaped hearing-aid axis and containing acoustic-electric transducers, electric-acoustic transducers and electronics. One shell end, usually the tapering end, constitutes the acoustic output device to the ear.




Such behind-the-ear hearing aids include a compartment to hold an ordinary or rechargeable battery. Such hearing aids use a button cell that is an ordinary or rechargeable battery. An axis of the battery is transverse to the above-mentioned axis of the hearing-aid shell. The design includes a hinging lid for the hearing-aid shell and retaining means for the cylindrical battery case that are arranged such that the latter's cylinder axis runs parallel to the pivot axis of the hinging lid. This configuration has several drawbacks.




Because the cylindrical case of the battery is transverse to the longitudinal axis of the curved, hook-shaped hearing-aid shell, the battery case wastes a relatively substantial space within the hearing aid. Moreover, there are mold parting lines between the hinging lid and the hearing-aid shell that run essentially along generatrices of the curved, hook-shaped hearing-aid shell. At least some of these parting lines will rest directly against the user's skin when in operation. Therefore, the parting lines constitute a comparatively elongated, critical site through which perspiration, humidity etc. may enter the battery compartment.




SUMMARY OF THE INVENTION




The present invention is directed toward eliminating or reducing the aforementioned drawbacks. According to the present invention, the battery compartment is situated at the shell end opposite the acoustic output device. The battery compartment is configured to receive a cylindrical rechargeable or ordinary battery case such that the cylinder axis of the battery compartment runs substantially coaxially with the hearing-aid longitudinal axis. Accordingly, an optimally minimal receiving volume or space is needed for the ordinary or rechargeable battery on account of the substantially cylindrical cross-section, in particular the inside cross-section of the hearing-aid shell, because the battery case now can be inserted coaxially with the hearing-aid tubular axis and in practice flush with the shell wall.




In a preferred embodiment of the invention, the above cited compartment comprises a first, preferably resilient, preferably central electric terminal, preferably also coaxial with the hearing aid's longitudinal axis, and at least one second electric terminal in the region of the erect compartment wall.




Even though merely two electric terminals suffice to contact a battery placed in the compartment, it may be advantageous in some circumstances to use more than two terminals in the compartment as regards another preferred embodiment of the hearing aid of the invention. The battery compartment of the hearing-aid shell, instead of holding an ordinary battery or a rechargeable battery, may receive the plug-in element of an attachment module, or an add-on module, to make electrical contact with at least two or more electric terminals. As regards the attachment module, which in this design includes the actual battery compartment at the hearing aid shell, it comprises a compartment at least substantially identical with the above mentioned compartment in the hearing-aid shell. In this manner, the module can be plugged into the battery compartment of the hearing-aid shell and the electric power then is supplied to the hearing aid by a cylindrical ordinary or rechargeable battery placed in the attachment-module compartment.




In this design, of course, more than one attachment module may be connected to the actual hearing-aid shell so as to practically extend the hook-shaped hearing-aid shell.




Whether the compartment is situated in the hearing-aid shell or, as mentioned above, is in an attachment module, it is furthermore fitted with a lid. The lid, in its closed position, is substantially perpendicular to the longitudinal axis of the hearing aid and preferably can be locked only by using a tool. This feature assures safety. For instance, when the hearing aid is used by children: lacking a tool, for instance a screwdriver, it will be impossible to remove the ordinary or rechargeable battery from the hearing aid.




The cited lid is of modular design and preferably can be removed in non-destructive manner from the hearing-aid shell. For example, after the lid has been removed, the lid can be reused again on the hearing-aid compartment or used on the compartment of an attachment module.




Furthermore a code, for instance a color code, may be mounted on behind-the-ear hearing aids, to identify which ear, left or right, is to be fitted with the particular hearing aid.




In order to avoid fixed coding during the manufacture of comparatively complex parts, the invention proposes furthermore that the above mentioned lid be fitted with a left/right ear code, preferably located on an externally visible part of a lock mounted on the lid. In this manner all lids can be manufactured identically and externally coded parts, for instance coded in red or blue, will only be inserted during the assembly of a simple lock.




In an especially preferred embodiment of the hearing aid of the invention, an add-on module or a further add-on module with a plug-in element is inserted in the aforementioned compartment, in the hearing-aid shell or in that of an add-on module. The add-on module preferably encloses a rechargeable battery.




In a highly preferred embodiment, the rechargeable battery is a lithium battery in which the energy density is advantageously higher than that of other rechargeable batteries especially as regards the hearing-aid application. The preferably encapsulated unit of rechargeable battery and add-on module also preferably is fitted with a charging regulator. The charging regulator precedes the rechargeable battery on the input side and preferably includes an inductive charging input. The charging power is applied as desired through a transformer and without externally accessible and damage-susceptible rechargeable-battery terminals. In particular when an Li-ion rechargeable battery is used in such preferred manner, its effective voltage will be matched to requirements of the electronics following the hearing-aid by a voltage regulator on the output side of the add-on module.




Basically it is highly advantageous to use an Li-ion rechargeable battery as the electric power source for a hearing aid, whether of the behind-the-ear or the in-ear type, and to exploit the properties of this kind of battery which are most advantageous with respect to hearing aids.




In accordance with further aspects of the invention, a number of substantial advantages regarding compactness, ease of maintenance and long life are offered compared to using other kinds of batteries.




The present invention provides a behind-the-ear hearing aid of modular design and having a hook-shaped shell fitted at one of its ends with a receiving compartment fitted with at least two accessible electrical terminals. A module's plug-in element is insertable into the receiving compartment, and the module, in turn, has its own compartment substantially identical with the aforementioned one in the hearing-aid shell. Leaving aside the question how and where an ordinary battery, or a rechargeable one, is stored in the behind-the-ear hearing aid, it is intrinsically highly advantageous to situate the cited receiving compartment in the hearing aid to selectively allow correspondingly designed attachment modules being mounted on the same basic hearing-aid configuration.




An attachment module of the invention for a hearing aid of the above kind comprises a plug-in element preferably subtending a substantially cylindrical external surface, a receiving compartment situated at the module and opposite the plug-in element to receive an element substantially shaped like the plug-in element and which can be locked by a preferably detachable, preferably tool-lockable lid. The attachment module preferably is in the form of modules for a wireless communication interface or a plug adapter module to adapt the hearing aid or further acoustic/electric transducers, a rechargeable-battery module which typically is larger than conventionally used ordinary batteries, a programming module or a mechanical drive module.




A further attachment module for the hearing aid consists of a first portion having an external cross-sectional contour substantially corresponding to the external cross-sectional contour of the hearing aid, and a second portion of a comparatively lesser diameter, and a rechargeable battery. Preferably, this attachment module is encapsulated per se and, contrary to the module cited before, does not include its own compartment. Preferably, the rechargeable battery is integrated into the first, thicker portion, to be followed by a voltage regulator in the second, thinner plug portion. Moreover, a storage-battery charging regulator is preferably present in the first above cited portion and is preferably connected at the input side with an inductive pickup to be able to feed the charging power using a transformer, that is, being free of externally accessible terminals.




In a preferred embodiment and on account of the reasons given above, the rechargeable battery present in this attachment module preferably is a Li-ion battery.











BRIEF DESCRIPTION OF THE DRAWINGS




The behind-the-ear hearing aid of the invention and the attachment module of the invention are elucidated in an illustrative manner below in relation to the Figures showing a presently preferred embodiment of the behind-the-ear hearing aid.





FIG. 1

is a simplified longitudinal section of a behind-the-ear hearing aid of the invention,





FIG. 2

is a perspective of the hearing aid of the invention,





FIG. 3

is a perspective of the preferred embodiment of a battery-compartment lid at the hearing aid of the invention,





FIG. 4

is the topview of the lid of

FIG. 3

with segments for left/right ear coding,





FIG. 5

is a perspective of, on one hand, the shell-segment of the hearing aid of the invention and on the other hand the add-on module of the invention,





FIG. 6

is a view on an enlarged scale of the electric/acoustic transducer system unit of the hearing aid of the invention of

FIG. 1

,





FIG. 7

is a simplified and schematic view of a drive means of the hearing aid of the invention,





FIG. 8

schematically shows the unit of

FIG. 6

to elucidate the acoustic couplings, and





FIG. 9

shows another preferred embodiment of an add-on module in the form of a signal-flow block diagram.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS





FIG. 1

is a partly simplified longitudinal section of the behind-the-ear hearing-aid assembly, of which the particular operational components or portions shall be discussed first. The hearing aid


1


comprises a curved, horn-shaped tubular shell having a central axis A. The shell is fitted at its thinner, curved end with an acoustic output device in the form of a connecting stub


5


to a coupling tube entering the ear. The connecting stub


5


is exchangeably slipped onto or screwed on a tube stub


9


seated in a shell segment


3


.




The inner duct


7


of the connection stub


5


continues through the tube stub


9


into the transfer duct


11


in the shell segment


3


. The transfer duct


11


is, in turn, coupled within a section


13


of the shell segment


3


to an electric/acoustic transducer system


15


.




As shown by

FIG. 1

, the transfer duct


11


runs along the inner curvature of the shell segment


3


such that a space is subtended toward the outer curvature of the shell by a microphone unit


17


. A lid


19


is integrated in this zone of the shell segment


3


and comes to a stop in the region of the apex of the hearing aid against a plug shaft


21


. As shown in particular in

FIG. 2

, the lid


19


runs along generatrices M of the hearing-aid shell as far as (

FIG. 1

) the region of the electric/acoustic transducer system


15


. The microphone unit


17


is accessible once the lid


19


has been removed and preferably makes electrical contact merely by means of a flexprint strap (not shown). The microphone unit


17


is tipped over the transfer duct


11


, and it rests against an acoustic input slot


23


.




When the lid


19


is closed, at least two microphone orifices of the microphone unit


17


are opposite an inset


25


in a slot


23


of the lid


19


. The inset


25


is acoustically transparent and comprises a plurality of apertures between the ambience U and a balancing volume V, the latter being left unencumbered between the discrete microphone orifices and the inset. Preferably, the inset


25


is made of a sintered material, in particular of sintered polyethylene, and moreover it is preferably coated in hydrophobic manner. The sintered material moreover subtends a “mesh” fineness between 10 and 200μ and with an open-pore rate preferably above 70%. Furthermore, the microphone unit


17


and the inset


25


in the slot


23


are mounted to the hearing aid


1


so that, when the hearing aid is being used, they shall be, if possible, wholly shielded against dynamic ambient air pressure by being positioned in the zone of the apex of the horn-shaped tubular base unit (FIG.


1


). In particular as regards the embodiment of a directionally sensitive acoustic/electric transducer system using the aforementioned at least two mutually spaced microphones, the feature of the gap V entailing common mode suppression tends to cancel identical acoustic signals each at a different input along the inset


25


on account of the balancing effect of the volume V.




Furthermore the inset


25


acts as a soil shield and is easily cleaned on account of its preferred hydrophobic coating.




Another advantage of the inset


25


having a plurality of apertures, closely related to the above mentioned common mode suppression, is that any soiling should affect both microphones equally. The directional characteristics will remain unaffected, whereas soiling is a basic problem in conventional directional microphones having two or more discrete orifices.




Reference is made to the European patent document A 0,847,227 of this applicant regarding said inset


25


and its effects.




An electronics


27


follows the electric/acoustical transducer system


15


in the shell segment


3


and in turn is followed by a battery compartment


29


. A power switch


31


is present on the outside of the shell segment in the zone between the battery compartment


29


and the electronics


27


. The perspective of

FIG. 2

shows especially clearly the connecting stub


5


, the shell segment


3


, the lid


19


having an acoustic input slot


23


and an inset


25


, further the power switch


31


.




The Battery Compartment




The battery compartment


29


situated at end of the shell segment


3


receives a cylindrical, flat, ordinary battery or a correspondingly shaped rechargeable battery


33


such that the axis of the cylindrical battery, which has end surfaces


33




u


and


33




o


, is situated at least substantially coaxially with the longitudinal axis A of the hearing-aid shell.




A first resilient electrical terminal


35


is present at the bottom


30


of the battery compartment


29


centered on the axis A, and a second electric terminal


37


rests resiliently against the side surface of the battery


33


. The battery compartment


29


can be closed by a lid


39


which, in its closed position, is transverse to the axis A and is supported in a pivotable or bayonet-lock manner on the shell segment


3


at


41


or on the battery compartment


29


.




Substantial advantages are offered by this transverse configuration of the battery


33


in the hearing aid.




The surface sealed off by the lid


39


is comparatively large, so that it may be put to further uses as shall be elucidated below. Moreover, due to the battery-compartment lid


39


being situated at the greatest depth of the hearing aid and the lid's sites abutting the shell segment


3


being transverse to the axis A, penetration of perspiration into the battery compartment is hardly critical anymore. In this design of the battery compartment, the electric terminals


37


and


35


are protected inside the compartment, the lid


39


is free of electric terminals. Also, the substantially cylindrical inner space of the shell segment


3


is exploited fully and there is practically no dead space anymore.





FIG. 3

is a perspective view of a preferred embodiment of the battery-compartment lid


39


designed as a hinged lid. This lid is easily detached from, or snapped into the pivot bearing


41


of

FIG. 1

on account of the resilient hinge


43


. In a preferred embodiment, the lid is further fitted with a lock


45


and a resilient pawl


46


.





FIG. 4

shows an outside view of the lid


39


of FIG.


1


. The lock


45


can be operated from the outside only using a tool, for instance a screwdriver, and for that purpose it is fitted with a drive means


49


in a rotating disk


47


. The disk


47


is integrated into the hinge lid


39


only when the lock


45


is installed, and is dyed in specific manner. For instance, the disk may be dyed in two color codes, red and blue, thereby indicating whether the particular hearing aid is for the left or the right ear.




As already mentioned, the shown embodiment of the battery compartment


29


, and in particular the feature of the flat cylinder constituting the battery being coaxial with the axis A of the hearing aid, does offer a substantial advantage: the hearing aid shown in

FIG. 1

represents a basic configuration.




It is frequently desirable to amplify this basic configuration with add-on options. Such add-on options may be an interface for wireless signal transmission, with a programming plug-in element, a further audio input, a larger rechargeable-battery compartment, a mechanical actuation system, etc. For that purpose the battery compartment shown in

FIG. 1

is redesigned as shown by FIG.


5


. The battery


33


is removed from the compartment and in its stead the plug-in element


34


of a corresponding add-on module


51


is plugged-in, and is made to electrically contact the corresponding terminals


35




a


and


37




a.






Where such add-on modules are used, further electric terminals are easily provided in the compartment


29


.




The compartment


29




a


acting as the actual battery compartment, together with the battery


33


, now is present in the add-on module


51


. The lid


39


is also removed from the shell segment


3


and snapped into position onto the add-on module or is affixed to it in the manner of a bayonet affixation.




Several such modules


51


may be stacked onto the base module of the hearing aid. Preferably, the particular affixation of the add-on modules


51


is implemented at a detent


43




a


, similarly to the hinge


43


at the hinged lid


39


, and by a pawl


46




a


similar to the pawl


46


at said hinged lid


39


, or, as regards bayonet locks, by appropriate insertion and locking by rotation.




In this manner the hearing aid can be built up modularly in the simplest possible manner and as desired. The ordinary battery or the rechargeable battery


33


always remains immediately accessible from the outside.




Electric/Acoustic Transducer System




The design and support of the above cited transducer system


15


in the shell segment


3


is shown in simplified manner in FIG.


6


and in elevation in FIG.


1


. The transducer system


15


includes a loudspeaker (omitted), with a loudspeaker diaphragm, encapsulated inside a loudspeaker enclosure


53


. The acoustic waves generated by the loudspeaker diaphragm are coupled from the space at the back side of the membrane in the loudspeaker enclosure


53


through apertures schematically indicated at


55


into the ambient space U


53


of the loudspeaker enclosure


53


. As shown by the arrow S, the acoustic signals are coupled from the space at the front side of the membrane into the transmission duct


11


shown in FIG.


1


.




The loudspeaker enclosure


53


is supported on all sides in substantially freely vibrating manner by elastic rubber bearings


57


. The comparatively large space U


53


is defined by the supports


57


between the outer wall of the loudspeaker enclosure and a case


59


, the space U


53


significantly enhancing the bass tones. The resonance chamber at the back side of the membrane is enlarged by a multiple by the space U


53


. In order that the space U


53


can be acoustically effective over the full periphery, the case


59


and its support


61


are tightly connected.




As a result, the volume of the support of the loudspeaker system is utilized optimally acoustically. The case


59


furthermore acts in preferred manner as a magnetically shielding case and for that purpose preferably shall be made of m-metal. The case is beaker-like and is hooked in sealing manner in the form of a plastic support into the support


61


. The above mentioned resilient and preferably elastic rubber bearings


57


are tensioned between the case


59


, the support


61


and the loudspeaker enclosure


53


.




The above discussed acoustic coupling is shown in strictly functional manner in FIG.


8


. The membrane


54


of the loudspeaker in the enclosure


53


defines in this enclosure a first space R


1


, which is coupled to the acoustic output device of the hearing aid denoted by S and a second space R


2


, which is coupled by one or more apertures


55


with the space U


53


subtended between the case


59


and the enclosure


53


.




Power Switch


31







FIG. 7

shows a preferred embodiment of the power switch


31


in simplified and diagrammatic manner. The power switch


31


includes a toggle key


63


unilaterally resting at point


65


.




The toggle support


65


is integrated into a slide


67


resting in linearly displaceable manner, as indicated by the double arrow F, relative to the shell segment


3


. As diagrammatically shown by the spring-loaded terminal


69


, which is stationary relative to the shell segment


3


and the shunt terminal


70


at the slide


67


, the hearing aid is turned ON and OFF by means of the key


63


when moving the slide.




A borehole


72


is present in the slide


67


and is crossed by an electric pin terminal


73


affixed to the shell segment


3


. This pin terminal


73


is spanned by a resilient electric terminal element


75


mounted on the slide


67


and preferably made of an elastic-rubber, at least partly electrically conducting plastic, to constitute a key, in the manner known for instance from remote-control keyboards. When toggling the key


63


in the manner shown by the double arrow K, the terminal element


75


makes contact with the pin terminal


73


and thus establishes electrical connection between them. Even though a number of possible electrical connections suggest themselves to the expert, including the switching path S


1


as implemented by the slide motion F and the switching path S


2


implemented by toggling the key


63


, preferably, however, the spring-loaded terminal


69


shall be connected to the hearing-aid battery


38


, and the jumper terminal


17


to the terminal element


75


, as shown in dashed lines in FIG.


7


. Accordingly, the pin terminal


73


acts as the electrical output device of the power switch.




In operation, the power switch


31


acts both as an ON/OFF slide switch and additionally, when in the ON position, as a toggle switch. As a result of this arrangement, the electronics


27


of

FIG. 1

is controlled stepwise, for instance to implement rapid setting of amplification by the individual.




Accordingly the power switch


31


combines the two functions of slide switch and toggle switch, and this combination of functions is exceedingly advantageous, particularly for the behind-the-ear hearing aid. The operational differential precludes confusing the functions, such a confusion being substantially more critical when using two switches for the two cited functions.




Design of Shell Segment


3






As shown in particular by

FIG. 5

, the shell segment


3


consists of a curved and correspondingly shaped tubular part. In a preferred embodiment the shell segment


3


is integral and preferably made of plastic. However, unlike the conventional design of such hearing aids, the shell segment cannot be separated into two half-shells along generatrices M shown in FIG.


5


. As a result, the assembly of the components into the shell segment


3


also is predetermined: they are merely inserted into the tube, which is a simpler assembly than for opened half-shells. Furthermore, an integral, tubular design offers the advantage of much increased mechanical strength relative to a split shell. In turn, the thickness of the shell-segment wall can be reduced and hence the shell also may be made more compact. Alternatively, if the external volume is kept constant, an increase of the available inside space will be achieved.




Rechargeable-Battery Module





FIG. 9

shows a special add-on module


51




a


which, like the module


51


described in relation to

FIG. 5

, is inserted into the battery compartment


29


or, if an add-on module


51


is already inserted therein, is placed into the compartment


29




a


of the already inserted add-on module


51


.




The geometry of the add-on module


51




a


is shown in merely schematic manner in FIG.


9


. The add-on module


51




a


is a rechargeable-battery module and, contrary to the case of the module


51


of

FIG. 5

, lacks its own receiving compartment


29




a


but preferably is enclosed per se in encapsulated manner. Its main portion


52


, like that of the add-on module


51


, cross-sectionally matches the cross-sectional contour of the shell segment


3


, and, like the add-on module


51


, comprises an integrated plug-in element


34




a


and further the design steps described in relation to the module


51


. Preferably a rechargeable-battery unit


80


is integrated into the main portion


52


, preferably comprising a Li-ion rechargeable battery


81


and a charging regulator


83


servicing the rechargeable battery


81


and preceding the rechargeable-battery unit


80


. The charging regulator is operationally connected at the input side to an inductive pickup


85


which, during charging of the rechargeable battery


81


, forms the secondary of a transformer power transmitter together with the primary side


87


of a charger shown in dashed lines.




An output voltage regulator


89


, a DC/DC converter, is preferably mounted in the plug element


34




a


at the output side of the rechargeable-battery unit


80


. The regulator


89


transforms and stabilizes the output voltage of the rechargeable battery


81


to, and at, the voltage values required by the electronics of the hearing aid. The output voltage from the regulator


89


is applied to the electric terminals at the module


51


a analogously to those of the module


51


of FIG.


5


.




Advantages of the Overall Configuration




It is clear from

FIG. 1

that the individual components (especially


11


,


15


,


27


,


29


and/or


51


,


51




a


) can be assembled by being inserted axially and consecutively into the shell segment


3


. The shape of the shell segment


3


including corresponding guide means assures rapid and accurate positioning, the mutual electrical contacts of the electrically powered components being solder-free and implemented by spring-loaded electric terminals. As a result the components to be used may be pre-tested and sized without fear of degradation and then be assembled. Assembly is easily automated. The full shell, with shell segment


3


and lid


19


or


39


, being fitted with appropriate seals at contact zones, is easily sealed.




The preferred embodiment of the electric/acoustic transducer


15


assures optimal magnetic shielding of the loudspeakers and optimal acoustic shielding against body acoustics.




Powering the hearing aid of the invention from a rechargeable-battery module, in particular from a Li-ion rechargeable battery, represents a most ecological technology which is also advantageous with respect to maintenance, and such features are enhanced by the possibility of inductive recharging in the absence of externally exposed electric terminals.



Claims
  • 1. A hearing device having a shell, an electric/acoustic transducer and electronics within said shell, one end of said shell constituting the acoustic output to the ear and further comprising a compartment at the other end of said shell, a module removably introduced into said compartment and comprising a battery and a voltage regulator, said voltage regulator having an input operationally connected to said battery and an output in electric contact with said electronics.
  • 2. The device of claim 1 being a hearing aid device.
  • 3. The device of claim 1 being a behind-the-ear hearing device.
  • 4. The device of claim 1, further comprising an acoustic/electric transducer within said shell.
  • 5. The device of claim 1, said shell with said module introduced being hook-shaped.
  • 6. The device of claim 1, wherein said battery is a rechargeable battery.
  • 7. The device of claim 6, wherein said rechargeable battery is a Li ion rechargeable battery.
  • 8. The device of claim 6, said module further including a charging regulator to charge said rechargeable battery.
  • 9. The device of claim 1, said module having a first portion of reduced diameter residing within said compartment and a second portion in extension of said shell, said voltage regulator residing within said first portion.
  • 10. The device of claim 1, wherein said battery is a rechargeable battery with a charging input, said charging input being operationally connected to a charging regulator, said charging regulator being conceived to receive charging input in a contact-free manner.
  • 11. The device of claim 10, said charging regulator having an inductive charging input.
Priority Claims (2)
Number Date Country Kind
PCT/CH99/00259 Jun 1999 CH
PCT/CH99/00537 Nov 1999 CH
CROSS REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. patent application Ser. No. 09/455,134 now U.S. Pat. No. 6,546,110, filed Dec. 6, 1999, which is a continuation-in-part of U.S. patent application Ser. No. 09/340,951, filed Jun. 28, 1999, now U.S. Pat. No. 6,731,770.

US Referenced Citations (4)
Number Name Date Kind
3101155 Lehr et al. Aug 1963 A
6173063 Melanson Jan 2001 B1
6320969 Killion Nov 2001 B1
6546110 Vonlanthen Apr 2003 B1
Foreign Referenced Citations (9)
Number Date Country
668154 Nov 1988 CH
36 24 568 Jan 1988 DE
3372809 Jan 1989 DE
37 23 809 Jan 1989 DE
297 18 104 Jan 1998 DE
0 263 294 Apr 1988 EP
0 337 195 Oct 1989 EP
0 500 988 Sep 1992 EP
2 305 067 Mar 1997 GB
Continuations (1)
Number Date Country
Parent 09/455134 Dec 1999 US
Child 10/361232 US
Continuation in Parts (1)
Number Date Country
Parent 09/340951 Jun 1999 US
Child 09/455134 US