Note: Descriptions are shown in the official language in which they were submitted.
1174135
Laryngoscope and improved blade therefor
Technical Field
The invention relates to a laryngoscope, and in
particular to a blade for a laryngoscope, which blade
has a light guide means extending between a heel of the
blade and an outlet point located between the proximal
and distal ends of the blade.
Discussion of Prior Art
A laryngoscope, the blade of which consists of stain-
less steel and in which a connecting cable runs from
the heel of the blade to a bulb holder which is located
between the proximal and distal ends of the blade is
already known from the pamphlet Med 0773 DE published
by Heine Optotechnik GmbH & Co. KGo of Hersching, West
Germany. The cable is contained in a channel which is
drilled after the blade has been manufactured or which
is made by soldering a U-shaped part forming the channel
onto the remainder of the blade. The manufacture of
this blade is relatively complicated and thus expensive.
A laryngoscope blade is also already known in which
a light guide essentially consisting of a bundle of opti-
cal fibers is provided between the heel and an outlet
point located between the proximal and distal ends of
the blade. Admittedly, this blade avoids the risk of
the patient suffering burns due to contact with the bulb
and is easier to clean and to sterilize in an autoclave.
However, it is relatively difficult, and hence, expensive
to produce.
Laryngoscopes which are made completely or partially
of a plastics material are also known but these are
intended for use only once and are consequently of very
simple construction and contain a light guide in the
form of a solid rod and which, during examination,
provides rather poor illumination of the area to b
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examined.
It is therefore an object of the present invention
to provide a laryngoscope blade which can be easily pro-
duced and which permits the best possible illumination
and cleaning, as well as sterilizing in an autoclave.
According to the invention, this object is achieved
when the blade together with the heel intended for fixing
the blade to a handle, is injection-molded from a
plastics material a~ter a light guide means has been
inserted into the injection mold. In practice, a suitable
light guide means is first located in an empty injection
mold in the desired position required in the final blade,
the mold is closed and the plastics material, in flowable
form, is injected into the closed mold. Since the light
guide means can be supported in the injection mold by
simple means, this results in simple and economical prod-
uction of the laryngoscope blade and hence of the entire
laryngoscope. Preferably, the plastics material selected
is a fiber-reinforced (e.g. glass or plastics fiber
reinforced) material, the softening point of which is
sufficiently high to withstand, without damage, the
temperatures prevailing in a sterilizing autoclave.
The design of the blade as a plastics molding has
the further advantage that the blade is virtually non-
dazzling to the user and that damage to the teeth ofa patient being examined, which can occur in the case
of spasms, is avoided with certainty. These two disadvan-
tages are virtually unavoidable in the case of the known
laryngoscope blades made from stainless steel.
The light guide means preferably comprises a housing
which is arranged between the heel and the light outlet
point of the blade and into which housing a bundle of
optical fibers has been inserted.
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This results not only in a further simplification
of the manufacturirlg process, since it is only r~ecessary
to insert the bundle of optical fibers into the housing,
to seal the housing if necessary and then to insert the
housing into the injection mold, but it also allows virtu-
ally any desired change in cross-sectional shape of the
bundle betweerl its two ends, without the bundle having
to be preformed in a separate operation.
Preferably, each end of the bundle of optical fibers
is respectively mour~ted in a holder which holders are,
in turn, located at the appropriate positions in the
wall of the housing to protrude somewhat beyond the
latter.
This gives secure and simple mounting of the bundle
of optical fibers in the housing and allows the light
guide means, comprising the housing and the bundle of
fibers, to be fixed accurately and reliably in the injec-
tion mold.
To ensure secure and simpler mounting of the housing
in the injection mold, it is possible to mold projections
onto the outside of the housing for holding the housing
in the correct position in the injection mold.
The housing receiving the bundle of optical fibers
preferably comprises two parts cemented together. The
holders for mounting the ends of the bundle can each
be provided with a collar which locates in a respective
groove in an appropriate orifice in one of the housing
parts so that the holders can be securely mounted in
the said one part of the housing before the other part
is applied thereto.
To pr~vent the plastics material, which enters the
injection mold during the injection molding of the blade,
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from penetrating into the housing and damaging the bundle
of optica~ fibers, the voids in the housing, remaining
after the bundle is located therein, are preferably filled
(e.g. with a plastics material), so that it is a closed
and fully filled housing which is embedded in the blade.
Alternatively, one or both parts of the housing can be
provided with supports, for example conical, pyramidal
or rib-like supports, which coact with the other part
in order to give the housing adequate strength to with-
stand the pressures exerted on it during the injectionmolding and thereby prevent damage to the bundle of fibers
either during injection or during the subsequent curing
of the injt?cted plastics material.
The light guide means can also comprise a tubular
member (e.g. a metallic tube) into which the bundle of
optical fibers is inserted. In this case, the fibers
of the bundle can be cemented at least to the opposite
ends of the tubular member so that the latter act as
the holders. Preferably, however, separate holders are
provided one at each end of the bundle and these holders
are in turn fixed (e.g- cemented or soldered) into the
ends of the tubular member.
Brief Description of the Drawings
Ont? embodiment of laryngoscope blade will now be
described, by way of example, with referenct? to the accom-
panying drawings, in which:-
Figuré 1 is a perspective view of the completelaryngoscope blade,
Figure 2 is a longitudinal St?C tion of the blade,
Figure 3 is a partially sectioned end view of the
blade, and
Figure 4 is a schematic sectional view of a ball
il74135
cage located in the heel of the blade.
Descriptiorl of Preferred Embodimerlt
The laryngoscope blade 1 shown in Figure 1 has an
upper surface 2 which serves as a support for the teeth
of a patient. The lower surface of a lower arm 3 of
the blade serves to hold the tongue of the patient out
of the way, and the arm 3 is connected via a web 4 to
the upper surface 2. The proximal end of the web 4 houses
a light guide means 5 (see Figures 2 and 3).
When the blade 1 has been introduced into the mouth
of a patient, the channel defined by the web 4, the lower
arm 3 and the surrounding pharynx of the patient, serves
as a guide for introducing an intubation catheter into
the trachea of the patient. A heel 6, which permits
an easy clip-on connection to a handle of the laryngoscope
(not shown) is molded onto the blade 1 at the proximal
end. As shown in greater detail in Figure 2, the light
guide means 5 extends from the lower surface of the heel
6 up to an outlet point 7 located between the proximal
and distal ends of the blade 1- An opening is formed
in the web 4 forwardly of the outlet point 7.
The light guide means 5 consists of a housirlg or
box 8 and a bundle 9 of optical fibers. The box 8 is
formed from a first part 10 and a lid 11. The first
part 10 and the lid 11 are secured to one another by
cement or by means of a suitable snap connection. One
or more supports 12, the or each consisting of a rib
or stud of conical cross-section is/are molded integrally
with the first part 10. At the proximal and distal ends
of the box 8, the bundle 9 of fibers issecured in place
by means of annular holders 13 and 14, respectively.
As shown in Figures 2 and 3, the cross-section of
the bundle 9 changes from circular at the proximal erld
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(i.e. holder 13 is of circular cross-Sectiorl) to oval
at the distal elld (i.e. holder 14 is of oval cross-
sectiorl)
During manufacture, the bundle 9 of optical fibers
is first threaded into the holders 13 and 14, which are
then inserted into grooved recesses in the end walls
of the first part 10, annular webs molded onto the holders
locating in the grooves and ensuring a positive connection
between the holders 13, 14 and the first part 10~ Between
the holders, the fibers of the bundle 9 are disposed
freely, much in the manner of a curved strand of hair.
The lid 11 of the box 8 is then placed upon the first
part 10 and joined thereto, for example by cementing.
The fibers of the bundle 9 which protrude beyond the
holders 13 and 14 are then ground and polished to ensure
good transmission properties for the light guide means
and ensure that a high proportion of the light entering
the heel 6 from the handle, exits from the outlet point
7. The lid 11 and the first part 10 of the light guide
means 5 can be provided with outwardly extending projec-
tions or studs (not shown), which further improve the
ease and accuracy of mounting the light guide means 5
in the injection mold.
After the light guide means 5 has been inserted
into the injection mold, the latter is closed with the
holders 13 and 14 serving to seal the injection mold.
During injection of the plastics material into the mold,
the support(s) 12 prevent(s) the box 8 collapsing, thereby
preventing the plastics material from penetrating into
the interior of the box 8 and damaging the fibers of
the bundle 9 during or after the high pressure injection.
Apart from possible minor final treatments, the blad~
1 is fully manufactured wherl it is removed from the mold
after the plastics material has hardened.
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In ~he preferred embodimerlt of the blade illustrated,
the heel 6 of the blade 1 is prcvided with a ball cage
wh,ch passes through the heel transversely to the
longitudinal axis of the blade 1. The ball cage 15 (see
Figure 4) consists of a sleeve 16 which, at its ends,
is provlded with constrictions, so that two balls 17,
located in the sleeve 16 and each having an external
diameter which is smaller than the internal diameter
of the sleeve 16, are held in the sleeve 16 in such a
way that they project somewhat beyond the ends of the
sleeve 16. The balls 17 are urged apart by means of
a helical spring 18. Prior to the injection molding
of the blade 1, the ball cage 15 is positioned in the
mold in such a way that, when the blade is removed from
the mold, the balls 17 project beyond the outer contour
of the heel 6 (see Figures 2 and 3). These balls 17
serve to removably lock the blade 1 on the handle of
the laryngoscope.
As Figure 2 also shows, the heel 6 of the blade
1 is provided with a recess, which serves to hook the
blade 1 onto a pin (not shown) of the handle. In this
recess, a stud 19 is provided, which is integrally formed
on the heel 6 and which, when the blade 1 is pushed over
the pin, snaps over the latter and then results in a
secure mounting of the blade 1 on the handle. More than
one stud 19 can be provided and these can be located
side by side and/or on opposite sides of the recess.
