Note: Descriptions are shown in the official language in which they were submitted.
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The invention relates to a clinical thermometer, either prismatic
or "flat-type", comprising a graduated capillary tube at one end of which is
located a bulb opening into the bore of the capillary tube and filled with
an expansion liquid such as mercury , the end of the capillary tube adjacent
the bulb having a constriction, while the opposite end of the tube is provided
with a grip made of a synthetic material, by means of which the thermometer
may be held.
Clinical thermometers of this kind, which operate as maximum thermo-
meters and with which the highest temperature of two readings may be deter-
mined, are usually mercury thermometers. As the temperature rises, the
mercury, which constitutes the expansion liquid, passes through the constric-
tion into the bore of the capillary. When the temperature falls, the mercury
cannot return to its bulb unless force is applied from the outside. Instead,
the column of mercury becomes separated, the full length thereof remaining
in the bore of the capillary, thus making it possible to read off, at the
upper end of the thread of mercury, the highest temperature reached.
A maximum thermometer is reset to a low reading by vigorous shaking,
or swinging, in a downward direction, which causes the separated column of
mercury to reunite with the liquid in the bulb.
Clinical thermometers of this kind, with a range of about 35 to 42C,
are known. They have the disadvantage that it is very difficult to shake the
column of mercury back through the constriction in the bore of the capillary.
Such thermometers are therefore frequently broken during this operation,
either because the thermometer slips from the fingers or, as often happens,
because it is struck against a stationary object in order to speed up the
return of the mercury to the receptacle. This disadvantage is especially
noticable in prismatic of "flat-type" clinical thermometers which, because
of their design, i.e. their small dimensions, are known to be harder to reset
than the larger enclosed-scale thermometers.
It is therefore the purpose of the present invention to improve
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the handling of such thermometers, especially before and after the taking of
temperatures, so that the thermometer may be not only rapidly, but also
reliably shaken down without slipping out of the user's fingers. In addition
to this, the user is also to be obliged automatically to hold the thermometer
in such a manner that it is correctly positioned for fast readings, this be-
ing particularly important in the case of existing thermometers with which
the temperature can be read only if the observer looks at the scale from a
position vertically thereabove.
According to the present invention, there is provided a clinical
thermometer in the form of a prismatic or "flat-type" thermometer comprising:
a graduated capillary tube having a bore, a bulb at one end of the capillary
tube, opening into the bore and filled with an expansion liquid and a con-
striction in the end of the bore adjacent the bulb; a grip of synthetic
material secured to the opposite end of the tube, in the form of an extension
from the end of the capillary tube, the handle having a plug-like section and
a holding section with at least one curved holding surface shaped to fit the
ball of a thumb, an opposing surface for an index finger, and a thickened
section at the end of the grip remote from the capillary tube; and a protec-
tive sleeve for the capillary tube, in the form of a truncated pyramid, the
major end of the said sleeve having an opening, the dimensions of which cor-
respond to those of the plug-like section of the grip such that the plug-like
section may be fitted into the said opening.
According to preferred embodiments of the clinical thermometer, the
curved holding surface for the thumb is arranged in such a manner that the
pressure between the thumb and the index finger is substantially parallel to
the direction of reading. The thickened section preferably has an extension
on the opposing surface for the index finger and/or on the holding surface,
the extension being preferably in the form of a bead.
The holding surface and/or the opposing surface of the grip may be
roughened, preferably by knurling, serrating, or the like.
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The desi~n may also be such that the end of the plug-like section
remote from the capillary tube has, on at least one side, between the plug-
like section and the holding section, a groove, and the large end of the
above-mentioned protective sleeve has an extension directed obliquely inwards,
in the form of a spring tongue integral with the sleeve, for engagement in
the groove in the assembled condition of the plug and sleeve. Similar grooves
may also be provided on the three sides having no holding surface for the
thumb.
If the protective sleeve is made in the form of a truncated pyramid
having a square cross section, the thermometer may be rotated through 90 and
may be inserted as desired into the said sleeve, where it will be held by
the clamping action of the oblique extension which, after the thermometer
has been inserted into the sleeve, snaps into one of the grooves in the plug-
like section of the grip.
In the accompanying drawing which illustrates an exemplary embodi-
ment of the present invention:
Figure 1 is a longitudinal section through a prismatic clinical
thermometer along the line I-I in Figure 2; and
Figure 2 is a plan view of the clinical thermometer illustrated
in Figure 1, as seen in the direction of arrow II in Figure 1 and in part
section.
The drawings illustrate, by way of example, a prismatic clinical
thermometer 1 having a capillary tube 2, at one end of which is located a
bulb 3 filled with mercury. Bulb 3 opens into the bore of the capillary, not
shown, the end of which adjacent the bulb has a constriction, also not shown.
Capillary tube 2 is provided with a scale 4.
The end of capillary tube 2 remote from bulb 3 has a grip 6 in the
form of an extension attachment, the shape of which is adapted to that of the
finger tips which hold it, to wit a curved holding surface 7 for the ball of
the thumb and an opposing surface 8 for the index finger.
The end of grip 6 remote from capillary tube 2 has a thickened
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Section 13 in the form of a bead, or one bead on holding surface 7 and one on
opposing surface 8. Thus, when the thermometer is held by grip 6, the danger
of the grip slipping through the fingers is largely eliminated.
This danger is lessened still further in that holding surface 7 and
opposing surface 8 have cross-knurling 10.
Grip 6 is made of a synthetic material, for example an impact
resistant ABS polymer, and is permanently secured to the relevant end of the
capillary tube.
Associated with capillary tube 2 is a protective sleeve in the form
of a truncated pyramid, major end 14 of which has an opening 11 the dimensions
of which correspond to those of a plug-like section 12 of grip 6, which is
fitted thereinto. Capillary tube 2 is thus centred. As may be gathered from
the drawing, opening 11 in protective sleeve 9 is also closed off by means of
grip 6.
A groove 16 is moulded into the three sides of plug-like section 12
not containing the holding surface for the thumb, between the plug-like
section and the grip itself. One edge at major end 14 of protective sleeve
9 has an extension 17 in the form of a spring tongue directed obliquely in-
wards by a small amount. Thus, when the clinical thermometer is fully in-
serted into the sleeve, the spring tongue snaps into one of grooves 16, orengages with the sloping extension of holding surface 7, depending upon the
position in which the thermometer is inserted into the sleeve. In this way,
the thermometer is held in the sleeve by the clamping action of the groove-
extension connection 16,17.
The novel clinical thermometer is thus easier and, more particular-
ly, safer to handle, since the design provides a better hold for the fingers
and a better hold in the protective sleeve. When held by the grip, it is
also at all times in the correct position for reading.
