U.S. patent number 3,890,961 [Application Number 05/390,695] was granted by the patent office on 1975-06-24 for disposable vaginal speculum.
This patent grant is currently assigned to Welch Allyn, Inc.. Invention is credited to John D. Connors, William C. Moore, Richard W. Newman.
United States Patent |
3,890,961 |
Moore , et al. |
June 24, 1975 |
Disposable vaginal speculum
Abstract
A two piece disposable vaginal speculum capable of full angular
and elevational adjustment. The instrument comprises an upper and a
lower blade connected together by a pin and slot connection to
permit relative pivotal and sliding adjustment of the blades. To
hold the blades in the desired adjusted position, one of them is
formed with a pair of spaced, arcuate rows of ratchet teeth and the
other is provided with a pawl selectively engageable with the
teeth. The row of teeth in which the pawl is positioned determines
the elevational adjustment of the blades while the particular tooth
in the row that is engaged determines the angular adjustment.
Inventors: |
Moore; William C. (Skaneateles,
NY), Connors; John D. (Auburn, NY), Newman; Richard
W. (Marcellus, NY) |
Assignee: |
Welch Allyn, Inc. (Skaneateles
Falls, NY)
|
Family
ID: |
38256902 |
Appl.
No.: |
05/390,695 |
Filed: |
August 23, 1973 |
Current U.S.
Class: |
600/222 |
Current CPC
Class: |
A61B
1/32 (20130101) |
Current International
Class: |
A61B
1/32 (20060101); A61b 001/32 () |
Field of
Search: |
;128/17,18 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: Layton; Henry S.
Attorney, Agent or Firm: Bruns & Jenney
Claims
We claim:
1. A vaginal speculum comprising a pair of separable blades of
resilient material fastened together by a pin and slot connection
to permit relative pivotal and spatial adjustment of the blades,
the pivotal adjustment permitting the blades to be moved between
closed and various degrees of open positions, one of the blades
having a double row of ratchet teeth positioned one above the other
and the other blade having a pawl selectively engageable with the
teeth in either of said rows, and means to enable the pawl to be
moved from one row to the other while the blades are in an open
position.
2. A speculum as defined in claim 1 wherein each of the blades has
a pair of spaced side walls extending rearwardly and downwardly
therefrom, each of the walls of said one blade having a double row
of ratchet teeth and each of the walls of said other blade having a
single pawl respectively engageable with either one of the double
rows of teeth.
3. A speculum as defined in claim 2 wherein the spaced side walls
of the blade having the pawls are connected at their lower
extremities by a bridging portion adapted to be engaged by the
thumb of the user to effect blade adjustment.
4. A speculum as defined in claim 2 including means interconnecting
the rows of ratchet teeth in each blade wall to facilitate movement
of the pawl on the confronting blade wall from one row to the
other.
5. A speculum as defined in claim 2 wherein the pawl holding edge
of each tooth in the ratchet teeth rows is tapered rearwardly from
the outside to the inside surface of the blade walls in which the
ratchet teeth rows are formed, and each pawl is formed with a
mating taper, said tapers on the teeth acting on the tapers of the
engaging pawls on the walls of the other blade to cam the two pairs
of walls into close engagement with one another.
6. A speculum as defined in claim 1 wherein the means for enabling
the pawl to be moved from one of the ratchet tooth rows to the
other while the blades are in open position includes an inclined
surface above the lower row of ratchet teeth and a bevelled surface
on the upper portion of the pawl which surfaces coact to spring the
pawl out of engagement with the lower row and permit its movement
to the upper row.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to surgical instruments, and has
particular reference to a two piece vaginal speculum of novel
construction. More specifically, the pieces of the speculum are
molded plastic which permits the instrument to be economically
manufactured and disposed of after use.
In the past, specula of the type with which the invention is
concerned have been made of metal and intended for long use. This
meant that the instrument had to be autoclaved after each use which
is time consuming and, with ever increasing labor costs, expensive.
More recently, therefore, the trend has been toward disposable or
"throw away" type instruments of relatively inexpensive
construction.
Disposable vaginal specula are disclosed in U.S. Pat. Nos.
3,528,409; 3,575,163; 3,650,266 and 3,716,047 which represent the
closest prior art known to the applicants. The last patent listed,
to W. C. Moore et al., is owned by the assignee of the present
invention. In most of the disposable vaginal specula developed
heretofore, there has been the problem that the lowest cost
instruments have afforded less than the full range of adjustments
permitted by the more expensive metal instruments and desired by
the physicians, while the instruments that have all of the
adjustment possibilities desired are not as low cost and the
practicality of throwing them away after use becomes marginal.
SUMMARY OF THE INVENTION
The speculum of the present invention is capable of full angular
and elevational adjustment and yet can be made at a cost low enough
to warrant discarding it after use. The speculum comprises only two
parts of molded non-toxic plastic material, the two parts
essentially being an upper and a lower blade.
The blades are connected together by a pin and slot connection to
permit relative pivotal and sliding adjustment. To releasably hold
the blades in the desired adjusted position, one of them is formed
with a pair of spaced, arcuate rows of ratchet teeth and the other
is provided with a pawl selectively engageable with the teeth. The
row of teeth in which the pawl is positioned determines the
elevational or spatial adjustment of the blades while the
particular tooth in the row that is engaged determines the angular
adjustment.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation of the disposable vaginal speculum of
the invention with the blades in closed position;
FIG. 2 is a fragmentary side elevation of the speculum with the
upper blade in elevated, full open position;
FIG. 3 is a partial sectional, partial side elevational view of the
lower blade taken substantially on line 3--3 of FIG. 4;
FIG. 4 is a rear elevation of the lower blade;
FIG. 5 is a bottom plan view of the handle portion of the lower
blade;
FIG. 6 is a fragmentary rear elevation of the upper blade;
FIG. 7 is a vertical section through the upper blade taken on line
7--7 of FIG. 6;
FIG. 7A is an enlarged transverse section through an upper blade
pawl taken on line 7A--7A of FIG. 7;
FIG. 8 is an enlarged, fragmentary side elevation of the lower
blade; and
FIGS. 9, 10 and 11 are fragmentary sectional views taken
respectively on lines 9--9, 10--10 and 11--11 of FIG. 8.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, and with specific reference to FIGS.
1-8, the disposable vaginal speculum of the invention is
essentially comprised of an upper blade or bill 14 and a lower
blade or bill 15 preferably of molded plastic material. The
configuration of the blades per se is conventional, the blades
shown being known as the Graves type in recognition of the
physician who originally designed them. However, almost any blade
configuration can be employed in carrying out the invention.
Formed integrally with the lower blade 15 are a pair of spaced,
substantially parallel walls 16 which extend rearwardly and
downwardly from the blade as shown. A depending handle portion 17
also is formed integrally with blade 15 and with the side walls 16,
the handle portion being faired into the lower surface of the
blade, FIGS. 1-3. Upper blade 14 also has a pair of spaced,
substantially parallel walls 18 formed integrally therewith, the
walls forming rearward and downward extensions of the blade.
As indicated in FIGS. 1 and 2, when the two blades are assembled,
the upper blade walls 18 are disposed outside the lower blade walls
16 in close confronting relation thereto. Upper and lower blades
are connected together by a pair of oppositely disposed pin and
slot connections, the upper blade walls 18 having slots 20 into
which lugs 21 on the lower blade project. The pin and slot
connections permit relative pivotal and sliding adjustment of the
blade as will be explained more fully hereinafter.
To releasably hold the blades in the desired adjusted position,
each lower blade wall 16 is formed with a double row of ratchet
teeth 22, FIGS. 1-3, 8 and 9, and each upper blade wall 18 is
provided with an integral pawl 24 that is selectively engageable
with the teeth in one of the rows, FIGS. 1, 6 and 7. The rows of
ratchet teeth are spaced apart and slightly arcuate, and the degree
of spacing between the blades, or elevational adjustment, depends
upon whether the pawls 24 are positioned for engagement with the
upper or the lower rows of teeth, compare FIGS. 1 and 2. When upper
blade 14 is elevated as in FIG. 2, the pivot lugs 21 engage the
lower ends of slots 20 whereas when the upper blade is in the
lowered or non-elevated position, FIG. 1, lugs 21 engage the upper
ends of slots 20.
Within the upper or lower ratchet tooth rows, the particular tooth
22 in the row that is engaged by its associated pawl 24 determines
the angular adjustment of the blades. Thus, in FIG. 1 the blades
are shown in solid lines in closed position, i.e. with no angular
adjustment, and the pawls are behind the first or rearmost tooth in
each lower row. Rotating the upper blade 14 about the lugs 21
results in the pawls engaging a particular pair of teeth and
changes the angular adjustment of the blades as shown in phantom
lines at 14'. Similar rotation of the upper blade in its elevated
position, FIG. 2, results in substantially greater expansion of the
cavity being examined.
To conveniently adjust the position of the upper blade 14, the
lower rear corners of its spaced walls 18 are connected together by
a yoke or bridging member 25, FIGS. 6 and 7, having a central
serrated portion 26 adapted to be engaged by the user's thumb.
Referring again to the upper and lower rows of ratchet teeth 22,
and with particular reference to the enlarged views of FIGS. 8-11,
a feature of the invention is the manner in which these rows and
the pawls 24 are formed and coact with each other. As best shown in
FIGS. 8 and 9, directly above each row of teeth 22 there is an
elongated opening 27 through the lower blade walls 16 in which
opening the associated pawl 24 is located when engaging one of the
teeth. To disengage the pawls, the upper blade 14 is pushed up a
short distance by exerting thumb pressure on the underside of the
serrated portion 26 of yoke 25.
As best shown in FIG. 6, the upper portions 28 of pawls 24 are
bevelled and when blade 14 is pushed up these pawl surfaces ride up
inclined surfaces 30 adjacent the upper edges of the elongated
openings 27 until the lower edges of the pawls clear the tips of
the ratchet teeth. As a result of this upward and slightly outward
movement, the upper non-bevelled portions of the pawls are brought
into engagement with non-inclined ledges 31 directly adjacent the
upper edges of the openings.
When the lower edges of the pawls clear the tips of the ratchet
teeth 22, upper blade 14 can be rotated to the desired new position
of adjustment. Upon reaching this, the physician simply stops
pressing up on the yoke 25 and the blade 14 moves down causing the
pawls to engage the teeth that are below them, the downward
movement and engagement being due to the external pressure that is
experienced by the blades in this type of speculum. As best shown
in FIGS. 8 and 11, the substantially vertical pawl holding edge 32
of each ratchet tooth is tapered rearwardly from the outside to the
inside surface of the lower blade walls 16 and this taper or bevel
operates to cam the engaging pawls inwardly. This in turn brings
the upper walls 18 into closer engagement with the lower blade
walls and provides a desirable self-locking feature. To aid in the
camming action, each pawl 24 is provided with a mating taper or
bevel as indicated at 24a in FIG. 7A.
To move the pawls 24 from the lower to upper rows of teeth and
thereby move upper blade 14 to its elevated position, the blade is
normally first rotated to closed position whereby the pawls are
positioned behind the first or rearmost tooth in each row. From
this position, upward pressure on the serrated portion of yoke 25
causes the pawls to slide up vertical recesses 34, FIGS. 8 and 10,
connecting the rear ends of the tooth rows, the bottom of the
recess in each lower blade wall lying in the same plane as the
ledges 31 previously described.
If the pawls 24 are in the lower rows and positioned so that the
upper blade is partially or all the way open, the pawls can be
shifted directly to the upper rows without rotating the blade to
closed position by simply pushing straight up on the yoke 25. This
moves the pawls out of engagement with the teeth in the lower rows,
up the inclined surfaces 30 above the lower rows and over the
surfaces 35 between the lower inclined surfaces 30 and upper rows
of teeth whereupon the pawls can spring into engagement with the
teeth in the upper rows directly above those they had engaged in
the lower rows. During such movement, the natural resiliency and
relative thinness of the plastic material permits the upper blade
walls 18 to be sprung outwardly enabling the pawls to pass over the
intermediate surfaces 35. To facilitate this direct upward
adjustment, the serrated portion 26 on the upper blade yoke 25
extends to the under side of the yoke as best shown in FIG. 7.
From the description thus far, it will be understood that the
angular adjustment of the upper blade 14 can be controlled
independently of its elevation and vice versa. Both adjustments,
however, can be effected by moderate thumb pressure on the serrated
portion of the yoke, this portion being comfortably positioned for
the thumb when the handle portion 17 of the instrument is grasped
by the physician.
In using the instrument of the invention, light for illuminating
the area being examined may emanate from the physician's headlight,
from a light unit connected to the handle 17 or other suitable
source. To enhance good illumination regardless of source, the
viewing passage through the instrument is substantially
unobstructed. The instrument disclosed is constructed so that it
may be used with a light unit (not shown) that can be removably
attached to the handle 17, the unit being arranged to direct light
substantially along the longitudinal axis of lower blade 15.
The handle portion 17, which is comfortable to hold with or without
the light unit, is formed with reinforcing ribs 36 that provide for
dovetail engagement with the light unit. As best shown in FIGS. 3
and 4, the lower blade is provided with a mucous wall or trap 37 to
prevent fluids from running down the handle. Light from the light
unit is directed over the top of this wall.
From the foregoing description, it will be apparent that the
invention provides a novel disposable vaginal speculum that can be
economically manufactured and yet has the full range of adjustments
afforded by more expensive, permanent type instruments. As will be
understood by those familiar with the art, the invention may be
embodied in other specific forms without departing from the spirit
or essential characteristics thereof.
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