Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to a scale for weighing a
patient.
This application is divided from Canadian appli-
cation 265,836 filed November 16, 1976.
In treating hospital patients the body weight and
its fluctuations are often of great importance, particularly
in cases of actual or impending electrolyte and water im-
balance. This determination supplements laboratory data,
and makes its interpretation easier, more accurate, more
relevant and more meaningful. It provides the clincial
observer with objective information which may prove vital
for proper and successful treatment of the patient.
In some case, it is necessary that bedridden
patients remain in their lying position. To weight such
patients the scale must be constructed so that the patient
can be transferred from the bed onto the scale and weighed
while he remains inclined. Such scales generally provide a
support structure usually freely movable over the ground by
mounting the structure on casters and a weighing mechanism
including a weigh-board carried for supporting the patient
in his inclined position during the weighing operation. The
weigh-board is sufficiently elevated above ground so that is
can be moved over the patient's bed. The support structure
includes a base disposed below the weigh-board which is
moved beneath the bed while the weigh-board is positioned
over the bed. To facilitate the storage of the scale while
not in use the weigh-board is normally attached to the
weighing mechanism so that it can be placed into an upright
storage position. A scale of this type is disclosed in U.S.
Patent 3,032,131 issued to Schmerl, May 1, 1962.
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There are other prior art scales for weighing
patients in their horizontal position which structurally
differ from the one disclosed in the referenced patent.
However, all scales have the general characteristic of
5 providing a horizontal weigh-board, a movable support frame
over the bed for receiving the patient while providing a
sturdy and stable support for the weigh-board.
Prior art scales for weighing patients in their
horizontal position generally enable accurate measurements
and they are relatively convenient for transferring the
patient from the bed to the scale and back. However, they
have a number of practical deficiencies which can render
` such scales cumbersome to handle and which may impair their
accuracy unless the attendant carefully isolates the scale,
and particularly the components of the weighing mechanism,
from coming into contact with objects such as the side of
the patient's bed, for example. If such contact does occur
the measured weight is of course, inaccurate. This is
particularly serious because such inaccuracies cannot be
detected after the measurement has been taken and the scales
provide no means of warning the attendant that the weight he
measures is inaccurate because the weighing mechanism is in
contact with a foreign object, e.g., the bed.
Accordingly, the prior art scales for weighing
bedridden patients in their horizontal position, while they
were adequate when properly operated, had several features
which could compromise their accuracy.
~ he present invention is broadly directed to
improving prior art scales for weighing bedridden patients
in their horizontal position to enhance the accuracy, safety
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and convenience of such scales.
In a first aspect the present invention is a scale
for weighing a patient in his horizontal position compris-
ing: a support frame including an upright post and means for
moving the frame over the ground and against a bed of the
patient so that the post is closely adjacent a side of the
bed; a weighing mechanism carried by the frame including a
flat weigh-board and means positioning the weigh-board so
that it extends horizontally away from the post at a point
sufficiently elevated to place the weigh-board over the bed
when the post is closely adjacent the bed side; and guard
means rigidly connected with the frame, disposed beneath the
board and preventing the bed side from contacting any part
of the weighing mechanism when the post is closely adjacent
the bed side and the board is positioned above the bed.
In a further aspect the invention is a scale for
weighing a patient in the horizontal position comprising: a
supporting frame including a horizontal base having a for-
ward end and an aft end and lateral sides, an upright post
connected to the base and positioned adjacent the aft end
and means permitting the frame to be moved about a support-
ing surface; a weighing mechanism including a carriage
vertically movable along the post and facing towards the
forward end of the base, a horizontally disposed weigh-board
connected with the carriage at a point spaced above the base
and on the side of the post facing the forward end of the
base, and means for determining the weight placed on the
weigh-board; whereby a generally horizontal object spaced
from the surface can enter the space between the weigh-board
and the base; guard means for shielding the carriage and
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parts connected therewith from being contacted by said
object. The guard means comprising a pair of upright bars
having their lower ends immovably secured to the frame, and
a brace connecting the upper ends of the bars with the frame
for stiffening the upper ends, the upright bars being
positioned forward of the carriage so that the bars inter-
cept the object before the object can contact the carriage
and influence the measured weight.
The provision of the guardrails forward of the
vertically movable carriage shields the carriage and there-
with the otherwise accessible components of the weighing
mechanism from contact with the side of the bed when the
scale is wheeled against the patient's bed. The attendant
need not pay attention to clear the weighing mechanism from
contact with the bed side and need not be concerned with the
possibility that during the weighing operation the scale
might move towards the bed so that contact between the bed
and the weighing mechanism would interfere with the accurate
weighing process. Instead, the present invention positively
prevents such contact and resulting inaccuracies in the
measured weight. Thus, the attendant can concentrate on the
weighing process without having to observe the patient's
safety and comfort, and adjust the relative position of the
bed or the scale.
An embodiment of the invention is illustrated in
the accompanying drawings in which:
Figure 1 is a side elevational view of a scale
constructed in accordance with the present invention;
Figure 2 is a front elevational view of the scale
shown in Figure l;
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Figure 3 is a fragmentary, enlarged cross-sectional
view and is taken on line 3-3 of Figure 1; and
Figure 4 is an enlarged, fragmentary side ele-
vational view and is taken on line 4-4 of Figure 2.
Referring to the drawings, a scale 2 constructed
in accordance with the present invention for weighing
bedridden patients in a horizontal inclination generally
comprises a supporting frame 4 including a base 24 which
mounts casters 6 for freely rolling the scale about a hori-
zontal support surface such as a hospital floor ~. The
frame has a forward end 10 and an aft end 12 and includes a
pair of spaced-apart upright posts 14 which have a generally
U-shaped cross-section defined by relatively short side
flanges 16, 18. The posts project upwardly from the base
adjacent the aft end thereof.
~ounted to base 24 is a weighing mechanism 20
which includes a horizontal weighing platform 22 disposed
above the base 24. The weighing mechanism further includes
spaced-apart carriages 26 which are vertically movable along
front face 28 of posts 14 via a suitable carriage lifting
mechanism (not shown in the drawing but illustrated in the
above-referenced U.S. Patent) and a pair of forwardly
extending, spaced-apart horizontal arms 30 mounted to the
carriages and protruding from adjacent the upright posts
towards the forward end 10 of frame 4. The carriages are
interconnected by a shield 27.
A weigh-board 32 is secured to one of the arms,
say the lefthand arm (as seen in ~igure 2), with hinges 34
for pivotal movement of the board about a generally hori-
zontal pivot axis (which is parallel to the arms) between a
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horizontal operative position and a vertical storage posi-
tion. The latter position is shown in phantom lines in
Figure 1 and 2. The weighing mechanism further includes the
conventional weighing beam, poises, sight indicators, etc.
mounted to an upright support 36 and collectively identified
in the drawings with reference numeral 38.
The scale is used as follows. During non-use the
weigh-board 32 remains in its vertical storage position to
reduce the required storage space and prevent the board from
interfering with normal hospital traffic. ~or use the
attendant pivots the board into its horizontal position and
raises it sufficiently (by raising carriages 26 along
upright posts 14) so that the weigh-board and the supporting
horizontal arms 30 are slightly above the upper surface of a
bed 40. The scale is now pushed forward to place the weigh-
board over the bed until a side 42 of the bed is closely
adjacent carriages 26. The patient is then transferred from
the hed onto the weigh-board by rolling and/or sliding him
onto the weigh-board. Thereafter the weighing operation is
performed and upon its completion the patient is transferred
from the weigh-board to the bed by reversing the above-
described steps.
Since carriages 26 and their interconnecting
shield 27 form part of the weighing mechanism any contact
between an outside object, such as bed 40, and the carriages
would render the weight measurement inaccurate. It is,
therefore, necessary to maintain a positive spacing between
the carriages and bedside 42. For that purpose the present
invention positions an upright guardrail 44 immediately
forward of the carriage. The lower end of the guardrail is
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rigidly secured to frame 4. To enable the positioning of
the scale as closely adjacent the bed as possible it is
preferred that the guardrail be constructed of a bar having
a rectangular cross-section with the thickness of the bar
extending parallel to horizontal weigh-board supporting arms
30. In this manner the bar takes up minimum space. To
prevent such a guardrail from being deflected when the scale
is pushed against the bedside, for example, an inclined
brace 46 is provided for each rail. The brace has a first
end connected to the upper end of the guardrail 44 while the
other, lower end is connected, e.g., bolted, to the aft end
12 of support frame 4. In this manner, both guardrails
providing a rigid protection for the weighing mechanism in
general and carriages 26 in particular, so that even if the
scale is pushed against the bedside 42 the measurement
remains accurate because no physical contact between the bed
and the weighing mechanism is possible. For particular
applications it might be desirable to include a horizontal
connecting plate 48 (shown in phantom lines in Figure 2
only) between the upper ends of guardrails 44.
To assure that the weigh-board remains in its
horizontal position during the weighing operation a latch 50
is mounted to a side 52 of the weigh-board facing horizontal
arms 30. The horizontal arm 30 opposite from the arm con-
nected to hinges 34 includes a catch such as a metal loop 54
positioned to engage a hook 56 of the latch. To return the
weigh-board to its vertical storage position the attendant
retracts a release lever 58 of hook 56 to disengage the hook
from the catch.
To prevent the weigh-board from being pivoted past
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its vertical position a stop 60 is secured to the carriage
26 which is adjacent the board when the latter is in its
storage position. The stop may be mounted to a suitable
support bracket (not shown in the drawings) and it is
preferably constructed of a resilient material to prevent it
from scratching or otherwise damaging the board.
A locking mechanism 62 for releasably retaining
the board in its vertical storage position is provided. The
locking mechanism comprises a horizonally disposed tube 64
disposed between and connected to posts 14. An elongate bar
or lever 66 is rotatable in the tube and has ends projecting
therefrom. A protrusion 68 extends perpendicular to the
lever and is positioned to engage side 52 of weigh-board 32
as is best seen in Figure 4. The opposite end of the lever
is fitted with a perpendicularly protruding handle 70 which
enables pivotal movement of the lever and therewith of
protrusion 68 between a first, board engaging and locking
position and a second, board releasing position (shown in
phantom lines in Figure 4). To facilitate the ease with
which the locking mechanism 62 is operated, a second handle
(not shown in the drawings) may be mounted to the end of
lever 66 from which protrusion 68 extends. In this manner,
the attendant can lock or release the weigh-board from
either side of the scale.
