U.S. patent number 3,683,850 [Application Number 05/071,728] was granted by the patent office on 1972-08-15 for apparatus for preparing blood specimens on slides.
This patent grant is currently assigned to Systematiks, Inc.. Invention is credited to Robert H. Grabhorn.
United States Patent |
3,683,850 |
Grabhorn |
August 15, 1972 |
**Please see images for:
( Certificate of Correction ) ** |
APPARATUS FOR PREPARING BLOOD SPECIMENS ON SLIDES
Abstract
An apparatus for preparing blood specimens on slides having a
test surface comprising guide means, a carrier mounted on the guide
means for movement back and forth therealong, the carrier providing
means for holding the slide to expose its test surface to receive a
drop of blood at a predetermined spot thereon. A member extends
toward the path of movement of the carrier preferably but not
necessarily to engage the test surface of the slide held thereby.
Drive means is provided for moving the carrier at a predetermined
speed in one direction along the guide means, the carrier being
movable in the opposite direction along the guide means to the
point at which such a drop of blood on the said predetermined spot
just contacts and wets the said member. The member which engages
the slide is preferably a resiliently flexible, thin strip-like
member which may be resiliently urged against the test surface of
the slide to provide, adjacent the test surface and in contact
therewith, a portion of the member which is at least slightly
curved about an axis extending generally parallel to the test
surface and generally perpendicular to the path of movement of the
carrier or which is inclined relative to the test surface.
Inventors: |
Grabhorn; Robert H.
(Indianapolis, IN) |
Assignee: |
Systematiks, Inc.
(Indianapolis, IN)
|
Family
ID: |
22103204 |
Appl.
No.: |
05/071,728 |
Filed: |
September 14, 1970 |
Current U.S.
Class: |
118/100 |
Current CPC
Class: |
G01N
1/2813 (20130101) |
Current International
Class: |
G01N
1/28 (20060101); B05c 011/02 () |
Field of
Search: |
;118/120,100,506
;117/12R,64R,3 ;128/2R,DIG.5 ;23/253R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Kaplan; Morris
Claims
What is claimed is:
1. An apparatus for preparing blood specimens on slides having a
test surface comprising guide means, a carrier mounted on said
guide means for movement back and forth therealong, said carrier
providing means for holding such a slide to expose its test surface
to receive a drop of blood at a predetermined spot thereon, means
for defining said spot, a member extending toward the path of
movement of said carrier and the test surface of the slide held
thereby, means for holding said member relative to said guide
means, and drive means for moving said carrier at a predetermined
speed in one direction along said guide means, said carrier being
movable in the opposite direction along said guide means to the
point at which a drop of blood on said predetermined spot of such a
slide contacts said member to effect a capillary spread of said
blood and whereby, upon return movement of the carrier in said one
direction, a blood smear is obtained.
2. The apparatus of claim 1 in which said member is resiliently
flexible and in which said holding means is positioned relative to
said carrier so that said member is resiliently urged against the
test surface of the slide to provide, adjacent the test surface and
in contact therewith, a portion of said member curving about an
axis to provide an outer peripheral surface to be contacted by such
a drop of blood.
3. The apparatus of claim 2 including means for stopping movement
of said carrier in said opposite direction at said point, said
stopping means being positioned so that, when said carrier is at
said point, such a drop of blood on said spot will contact and wet
said portion of said member.
4. The apparatus of claim 3 in which said axis of curvature extends
generally parallel to the test surface and generally perpendicular
to the path of movement of said carrier, said member being
cantilevered from said holding means so that said curved portion is
its free end portion.
5. The apparatus of claim 1 in which the portion of said member
adjacent and against the test surface is formed to extend toward
the test surface and in said opposite direction, and including
means for stopping movement of said carrier in said opposite
direction at said point, said stopping means being positioned so
that, when said carrier is at said point, such a drop of blood on
said spot will contact and wet by capillary action said formed
portion.
6. The apparatus of claim 5 in which said member is cantilevered
from said holding means so that said formed portion is its free end
portion.
7. The apparatus of claim 6 in which said member is a thin,
strip-like member, said formed portion being curved about an axis
extending generally parallel to the test surface and generally
perpendicular to the path of movement of said carrier.
8. The apparatus of claim 7 in which said member is resiliently
flexible, said holding means being positioned relative to said
carrier so that said member is resiliently urged against the test
surface of the slide.
9. The apparatus of claim 1 in which said drive means includes a
spring for moving said carrier in said one direction away from said
point.
10. The apparatus of claim 9 including means for controllably
resisting movement of said carrier by said spring, thereby to
determine the speed of movement in said one direction away from
said point.
11. The apparatus of claim 1 including means for mounting a roll of
tape and feeding discrete pieces of said tape to said carrier, said
discrete pieces serving as the slides.
12. The apparatus of claim 11 in which said mounting means is
connected to said carrier for movement therewith.
13. The apparatus of claim 1 in which the portion of said member
adjacent the test surface is formed to provide an inclined surface
extending the test surface and in said opposite direction, and
including means for stopping movement of said carrier in said
opposite direction at said point, said stopping means being
positioned so that, when said carrier is at said point, such a drop
of blood on said spot will contact and wet said inclined
surface.
14. The apparatus of claim 13 in which said member provides spaced
apart contact points which engage the test surface and a straight
edge portion extending transversely across and above the test
surface, said contact points being effective to hold said straight
edge portion at the desired height above and in parallelism with
the test surface.
15. The apparatus of claim 14 in which there are two of said
contact points engaging, respectively, opposite side edges of the
test surface and in which said straight edge portion extends
between said contact points.
16. The apparatus of claim 13 in which said portion of said member
is inclined at an angle of approximately 25.degree. relative to the
test surface.
17. The apparatus of claim 13 in which said portion is inclined at
an angle of from approximately 25.degree. to approximately
45.degree..
18. The apparatus of claim 1 in which said drive means includes a
spring motor, and transmission means drivingly connecting said
spring motor to said carrier.
19. The apparatus of claim 18 in which said transmission means
includes a rack connected to said carrier and extending in the
direction of said guide means and gear means drivingly connecting
said rack to said spring motor.
20. The apparatus of claim 19 including braking means drivingly
connected to said transmission means and arranged to control the
speed at which said rack is driven.
21. The apparatus of claim 20 in which energy is stored in said
spring motor by manually moving said carrier in said opposite
direction to said point.
22. The apparatus of claim 21 including means for stopping movement
of said carrier in said opposite direction at said point, said
stopping means being positioned so that, when said carrier is at
said point, such a drop of blood on said spot will contact said
member.
23. The apparatus of claim 21 in which the portion of said member
adjacent the test surface is formed to provide an inclined surface
extending toward the test surface and in said opposite direction,
and including means for stopping movement of said carrier in said
opposite direction at said point, said stopping means being
positioned so that, when said carrier is at said point, such a drop
of blood on said spot will contact and wet said inclined
surface.
24. The apparatus of claim 23 wherein the means defining said spot
is visible through said slide.
Description
It is a primary object of may present invention to provide an
apparatus for systematizing the preparation of blood film specimens
on glass slides so that the specimens can be viewed with a
microscope. Specifically, it is an object of my present invention
to provide an apparatus which will take the guesswork out of
preparing such specimens on slides by providing means proportioned
and designed correctly and repeatedly to draw a drop of blood
placed on a predetermined spot on the slide into a film which is
one cell layer thick.
Such specimens are conventionally and presently prepared on thin
rectangular pieces of glass, commonly referred to as slides.
Conventionally, the technician deposits a drop of blood on one
slide and then manually uses another slide to draw the blood into a
thin film and, in some cases improperly to scrape or spread the
blood into a thin film. The quality of the film obtained presently
depends upon the talent and capability and care of the technician
processing the specimen. It is well known in the blood testing
field that a great many of the slide specimens made using present
techniques are worthless for the testing purpose intended. This is
true because the manual manipulation of the drop of blood by the
second slide often damages blood cells within the drop and often
fails to provide a film which is one cell layer thick.
My apparatus is an important improvement in that it includes a
carrier mounted on a guide means for movement back and forth
therealong, the carrier providing means for holding such a slide to
expose its test surface to receive a drop of blood at a
predetermined spot thereon. I prefer to place, on the carrier
itself, a spot or dot which will be visible through the slide so
that the technician can place the drop of blood on the upper
surface of the slide, i.e., its test surface, to be in vertical
registry with the spot on the carrier. My apparatus includes a
member which preferably contacts the test surface of the slide for
uniformity purposes. The carrier is preferably manually movable
inwardly to the point at which a drop of blood on the said
predetermined spot will just contact and wet the portion of the
applicator member directly adjacent the test surface. Means are
provided for stopping the carrier at this point. At this point, the
member contacts and breaks the surface tension of the drop of
blood, and the blood spreads laterally on the member by capillary
action. Then, my apparatus includes drive means for moving the
carrier at a predetermined constant speed outwardly to move the
drop of blood away from the member. This outward movement, at the
proper speed, is effective to draw the drop of blood into a thin
film which is of the proper and desired thickness and the cells of
which are undamaged by the drawing process.
Utilization of the apparatus defining my present invention,
therefore, includes the steps of obtaining and depositing a drop of
blood on the test surface of a slide, moving the slide so that the
drop of blood just contacts and wets the portion of the member held
adjacent the test surface, and then moving the slide in the
opposite direction at a predetermined speed to draw the drop of
blood into a thin film.
It is important to note that my apparatus preferably involves using
a thin resiliently flexible member held against the test surface on
which the drop is deposited in such a manner that the drop contacts
an inclined smooth surface. This is in contrast to using the sharp
square and flat portion of a slide as the means for drawing a drop
of blood.
I prefer to use an elongated small diameter plastic hose, a length
of which has an enlarged cross section, to take the blood specimen.
Specifically, in accordance with the disclosures of my copending
application Ser. No. 824,977 filed May 15, 1969, now U.S. Pat. No.
3,633,566 and my copending application Ser. No. 165 filed Jan. 2,
1970, now abandoned, I use a small plastic hose or tube, each end
of which is connected to the rear end of a sharpened cannula. One
cannula is inserted into a person's vein and the other cannula is
sequentially penetrated through the closing means or stoppers of
tubes which are evacuated. The portion of the hose or tube which
has the enlarged cross section is close to the cannula inserted
into the vein so that a drop of blood of a predetermined size can
be obtained simply by squeezing the portion having the enlarged
cross section to force a drop out of the cannula and onto a slide.
I prefer to use a 21 thin wall cannula to penetrate the vein, and
the bore of this cannula will provide a drop of a desired size when
the cannula is first removed from the vein.
When the blood droplet is spread into a film, the cells will
randomly spread throughout the film, i.e., some red cells, some
white cells and some platelets will be in any area of the film
inspected. The red cells, white cells and platelets will appear in
much the same manner as a group of three differently sized marbles
resting on a flat surface to provide a layer which is one cell
thick, but with the cells being of different size. One cubic
millimeter of blood has approximately 41/2 million red cells, 4,000
white cells and about 150,000 platelets. Thus, there are more red
cells than anything else appearing in the film drawn. It is
important, therefore, in order to study the morphology of the white
cells and platelets that the film be one cell layer thick.
Importantly, white cells are studied carefully to classify them as
to granulocyte or lymphocyte or variety. Such determinations cannot
be made if the red cells are piled up against the white cells.
Blood film specimens, of course, are investigated under a
microscope, and unless the blood is drawn into a film which is one
cell thick, it is difficult to make any sight comparative
evaluations at all. For instance, if the film is properly one cell
layer thick and the cells are not damaged, a good comparative
determination as to the number of white cells with respect to the
number of red cells can be obtained.
Other objects and features of my present invention will become
apparent as this description progresses.
To the accomplishment of the above and related objects, my
invention may be embodied in the forms illustrated in the
accompanying drawings and the method described herein, attention
being called to the fact, however, that the drawings are
illustrative only, and that change may be made in the specific
constructions illustrated and described, or in the specific steps
stated, so long as the scope of the appended claims is not
violated.
In the drawings:
FIG. 1 is a perspective view showing one embodiment of my
apparatus;
FIG. 1a is an exploded perspective view of the internal mechanism
of the embodiment of FIG. 1;
FIG. 2 is a transverse sectional view of the embodiment of FIG.
1;
FIG. 3 is a perspective view of a preferred type of applicator
member usable in my apparatus;
FIG. 4 is a longitudinal sectional view of the apparatus of FIG.
1;
FIG. 5 is a fragmentary perspective of a portion of another
embodiment of my apparatus, this embodiment including means for
mounting a roll of tape and feeding discrete pieces of the tape to
be used as test surfaces in lieu of the conventional glass
slides;
FIG. 6 is a fragmentary sectional view showing the manner in which
a slide is moved in the apparatus of FIG. 1 to draw a film;
FIG. 7 is another fragmentary sectional view similar to FIG. 6
except that it shows the blood droplet contacting the applicator
member;
FIG. 8 is another fragmentary sectional view similar to FIG. 6
except that it shows the blood drawn into an exaggerated film;
FIG. 9 is a sectional view of another embodiment of my invention,
this embodiment including a different drive arrangement than that
shown in FIG. 1;
FIG. 10 is a sectional view taken from FIG. 9 generally along the
lines 10--10;
FIG. 11 is a fragmentary view showing diagrammatically the action
provided by the applicator member of FIG. 3;
FIG. 12 is a fragmentary view showing a different type of
applicator member;
FIG. 13 is an end view taken from the right-hand side of FIG. 12
and showing the manner in which the applicator member of FIG. 12
engages the test surface of the slide;
FIG. 14 is a fragmentary view showing one means for obtaining the
blood droplet;
FIG. 15 is a view of a slide showing diagrammatically the type of
film drawn by my apparatus; and
FIG. 16 is a view of a slide showing the type of film which is
drawn by conventional techniques.
Referring now to the drawings, and particularly to FIGS. 1, 1a, 2
and 4, it will be seen that my apparatus, indicated generally at
10, includes a base 12 and a housing cover 14 which is attached to
the base. The base 12 may be provided with rubber-like feet 16 and
the housing cover 14 may be attached to the base 12 by means such
as screws 18 which extend through apertures 20 in the base.
My apparatus 10 includes guide means 22 which may be integrally
formed with the base 12 as illustrated in FIG. 2, the guide means
including spaced apart longitudinally extending runners 24, 26
providing, respectively, slideways 28, 30. I provide a carrier 32
mounted on the guide means 22 for longitudinal reciprocable
movement back and forth therealong, the carrier 32 providing means
for holding a test slide as will be discussed hereinafter. It will
be seen that the carrier slides on the slideways 28, 30.
As best seen in FIGS. 1a and 2, each side of the carrier 32 is
provided with a longitudinally extending slot 34, 36. A pin 38, 40
rigidly attached to each runner 24, 26 extends into each slot 34,
36 to keep the carrier 32 on the slideways 28, 30 as the carrier
reciprocates. Each slot 34, 36 is provided with a down-turned
portion 42 at its outer end and a down-turned portion 44 at its
inner end, the down-turned portions of slot 34 being seen in FIG.
1a. These down-turned portions 42, 44 provide means for locking the
carrier 32 in its inner position or its outer position.
Specifically, when the carrier is pushed inwardly and then raised
slightly so that the pins 38, 40 engage the down-turned portions
42, the carrier is locked in its inner position; and, conversely,
when the carrier 32 is pulled outwardly and the pins 38, 40 are
engaged in the down-turned portions 44, the carrier is locked in
its outer position.
The carrier 32, which is preferably generally horizontally
extending, provides upstanding walls 46, 48, 50, 52 bounding a
rectangular surface 54 having means 56 which may be a spot of
paint, tape or the like on its upper surface. Test slides, one of
which is indicated at 58 in FIGS. 1a and 2, are placed on the
surface 54 with the sides of the test slide engaging, respectively,
the walls 46, 48, 50 and 52. It will be appreciated that the spot
56 will be visible through the clear glass slide 58.
Thus, the spot on the upper, test surface of the slide 58 which is
in direct vertical registry with the spot 56 is the aforesaid
predetermined spot on which a drop of blood is deposited in
accordance with my present invention.
A slider 60 is engaged with the runners 24, 26 to be longitudinally
reciprocable therealong. This slider 60, which is disposed to the
right of the carrier as viewed in FIGS. 1a and 4, acts as a pusher
for moving the carrier 32 outwardly as will be discussed
hereinafter. The slider 60 may or may not be fastened to the
carrier 32. In the illustrative embodiment, I show a plate 62
mounted on the outer end of the slider 60 by means of screws 64,
the plate 62 engaging the right-hand end of the carrier 32. This
plate 62 holds down the right-hand end of the carrier 32.
In the illustrative embodiment, each runner 22, 24 provides an
upright 66, 68 between which extends a trunnion 70. A conventional
and commercially available wound strip spring 72 is mounted on the
trunnion 70 with the free end 74 of the spring being connected to
the slider 60 by means of a screw 76. This type of spring 72 is
commonly referred to as a NEGATOR spring.
Referring to FIG. 4, it will be seen that the underneath side of
the slider 60 is provided with a cavity 78 in vertical registry
with and penetrated by the shank of the screw 76. A ball bearing 80
is placed in this cavity to ride on the surface of the base 12, and
the shank of the screw 76 extends into the cavity to engage the
ball bearing. By tightening the screw 76, the ease with which the
slider 60 will move on the runners 24, 26 can be adjusted. Further,
in FIG. 1a, I show a dashpot 84, the plunger 86 of which is
connected to the slider 66 by, for instance, the screw 76. This
dashpot 84 works in a conventional manner controllably to resist
movement of the slider, thereby to control movement of the carrier
32 in the direction of the arrow 90. The manner in which a dashpot
provides this function will be understood by those familiar with
mechanisms.
In FIGS. 1a and 4, I show an arrow 88 representing the movement of
the carrier 32 inwardly and an arrow 90 representing movement of
the carrier outwardly. The spring 72 is a drive means for moving
the carrier 32 at a predetermined speed in one direction as
indicated by the arrow 90 along the guide means 22. The carrier 32
is movable in the opposite direction as indicated by the arrow 88
along the guide means 22 to the point at which a drop of blood
placed on the aforesaid predetermined spot of the test surface of
the slide 58, i.e., in vertical registry with the spot 56, contacts
and wets an applicator member which will be discussed in detail
hereinafter.
A finger engageable push member 92 is provided for manually pushing
the carrier 32 inwardly to the point at which the drop of blood
contacts the applicator member. Stop means are provided for
defining this point. For instance, the engagement of the pins 38,
40 in the left-hand ends of the slots 34, 36 may serve as a stop
means for the carrier 32 when it moves in the direction of the
arrow 88. It will be appreciated that any such stop means may be
used.
Referring now to FIGS. 1, 6, 7 and 8, it will be seen that I have
illustrated an applicator member 100 including an applicator
portion 102 and a gripping portion 104. The gripping portion 104 is
provided with side notches 106, 108 and the applicator portion 102
terminates, at its distal end, with a transversely extending
straight edge 110. As best seen in FIGS. 1 and 2, the housing 14 is
provided with an opening 112 at its upper, left-hand end as viewed
in FIG. 1, this opening 112 terminating with a slot 114 into which
the applicator member 100 is inserted. The slot 114 provides
laterally extending notches 116, 118 which cooperatively engage,
respectively, the notches 106, 108 securely to hold the applicator
member 100 in position relative to the carrier 32. It will be
appreciated that this means of holding the applicator member
securely relative to the carrier 32 is illustrative and that any
number of such means may be used to accomplish the same
purpose.
The applicator portion 102 is preferably a thin resiliently
flexible strip-like plastic member. The applicator member 100 is
preferably held relative to the carrier 32 in such a manner that
the applicator portion 102 will be resiliently urged against the
test surface of the slide 58 as best seen in FIGS. 6, 7 and 8.
Referring to FIGS. 6, 7 and 8 it will be seen that the applicator
portion 102 is held in such a manner that it is curved to provide,
adjacent the test surface and in contact therewith, a portion 122
curving about an axis which is above the surface 58 and extending
perpendicular to the guide means 22, i.e., the path of movement of
the carrier 32. This portion 122 provides an outer peripheral
surface which is contacted by the blood drop B. Specifically, as
shown in FIG. 6, the blood drop B is placed at the aforesaid
predetermined spot on the test surface of the slide 58. Then the
carrier 32 is moved in the direction of the arrow 88. The
previously discussed stop means stops the carrier 32 at the point
at which the drop B just contacts and wets the outer peripherally
curved surface of the portion 122 adjacent the test surface of the
slide 58. As soon as the drop B contacts the portion 122, the blood
spreads laterally against the portion 122 by capillary action
because the surface tension of the drop is broken by the applicator
member. Then, the carrier 32 is moved in the direction of the arrow
90 at a predetermined preferably constant speed to draw the blood
into a film as shown in FIG. 8. Particularly, when the drop B is in
the position shown in FIG. 7, the drop adheres to the portion 122
of the applicator member 100 as well as to the said predetermined
spot on which it was initially placed. The movement of the slide in
the direction of the arrow 90 causes the blood in the drop B to be
drawn into a film.
If the carrier 32 is moved too fast in the direction of the arrow
90, the film will be broken. If the carrier 32 is moved too slow in
the direction of the arrow 90, the blood will be drawn into a film
which is too thick. Experimentally I have determined that a carrier
speed of approximately 1 inch per second is satisfactory. It will
be appreciated, however, that this speed will depend upon the
particular configuration of the applicator member, etc.
Referring now to FIGS. 3 and 11, it will be seen that I have shown
an applicator member 130 having two applicator portions 132, 134
extending away from a central portion 136. Each portion 132, 134 s
provided with notches 138 which perform the same function as the
notches 106, 108 discussed in conjunction with the applicator
member 100. Each applicator portion 132, 234 is bent or formed as
indicated at 140 a short distance from its distal edge 142. When
the applicator member 130 is snapped into the slot 114, the distal
edge 142 of its applicator portion 132 or 134 will engage and
extend transversely across the test surface of the slide 58 as
shown in FIG. 11. There will be a portion 144 extending between
this distal edge 142 and the bend line 140, this portion 144
providing a downwardly facing inclined surface extending toward the
test surface of the slide 58 and in the direction of the arrow 90,
i.e., the direction in which the slide 58 is pushed inwardly. The
slide 58 is stopped by the aforesaid stop means at the point at
which the blood drop B contacts and wets this inclined surface as
illustrated in FIG. 11. Then, the slide is moved in the direction
of the arrow 88 to move the drop B away from the applicator portion
132, 134. I prefer to construct the applicator member so that the
portion 144 (FIG. 11) is inclined at an angle of approximately
25.degree. relative to the test surface of the slide 58. It will be
appreciated that this angle of inclination also depends on several
factors including the size and shape of the applicator member and
that the angle of inclination may be from approximately 25.degree.
to approximately 45.degree. relative to the test surface of the
slide 58.
Referring now to FIGS. 12 and 13, it will be seen that there is
illustrated an applicator portion 144' directly adjacent the test
surface of the slide 58. The applicator member providing this
portion 144' has its distal edge 142' cut or otherwise formed as
indicated at 150 to provide spaced apart contact points 152, 154
which engage the lateral edges of the test surface of the slide and
a straight edge 151 extending transversely across and above the
test surface, the contact points 152, 154 being effective to hold
the straight edge 151 at the desired height above and in
parallelism with the test surface. This straight edge 151 may only
be held, for instance, 0.001 inch above the test surface.
It is not absolutely vital that the applicator member itself touch
the test surface of the slide. It is only necessary that the
applicator member have a portion which is close enough to the test
surface of the slide to be contacted and wetted by the blood drop
placed upon the test surface. I have found that it is more
convenient to engage the free end of the cantilevered applicator
member with the test surface of the slide in such a manner that the
blood drop will engage an inclined surface or a curved surface of
the applicator member in the same manner each time a film is made.
It will be appreciated that the drop B (FIG. 11) will engage more
area of the downwardly facing inclined surface of the portion 144
than it would if the portion 144 were extending perpendicularly to
the test surface of the slide 58.
Referring now to FIG. 5, it will be seen that I have constructed
the slider indicated at 60' in such a manner that it provides means
160, 162 for mounting a roll of tape 164 for movement with the
carrier indicated at 32'. This system of FIG. 5 is adapted to feed
discrete pieces of the tape 164 to the carrier 32' so that these
discrete pieces of tape can serve as test slides. Specifically,
tape is fed under a knife-edge bracket 166 as indicated by the
arrow 168 to cover the upwardly facing surface of the carrier 32'
on which the spot 56 is marked. The blood is then dropped onto the
spot of the tape which is in directe registry with the spot 56 so
that the smear or film can be made on the surface of the tape. The
means for supporting the roll of tape includes a pair of support
arms 160 extending rearwardly and upwardly from the slider 60' and
a trunnion 162 extending between the support arms 160. The only
significant difference between the structure of FIG. 5 and the
structure of FIGS. 1a, 2 and 4 is that the roll of tape is added so
that discrete pieces of the tape can be used as test surfaces.
Referring now to FIGS. 9 and 10, it will be seen that I have shown
another embodiment of my apparatus, indicated generally by the
reference numeral 10', this embodiment being similar to the
embodiment of FIGS. 1a, 2 and 4, except that a different drive
means 180 is utilized to drive the carrier 32 in the direction of
the arrow 90. Like reference numerals in FIGS. 9 and 10 represent
like parts in FIGS. 1, 1a, 2 and 4.
The drive means 180 is a commercially available spring-type drive
motor having an output gear 182 which I use to drive a rack 184
which reciprocates with the carrier 32. Thus, my apparatus of FIGS.
9 and 10 basically includes a spring motor 180 and transmission
means (output gear 182 and rack 184) drivingly connecting the
spring motor to the carrier 32. The spring motor of the drive means
180 is mounted above the path of the rack 184 on standoffs 186, 188
to hold its output gear 182 in mesh with the rack 184. While the
drive means 180 is commercially available and need not be discussed
in detail herein, it does include a strip spring 190 which is also
of the type usually referred to as a NEGATOR spring and portions of
which are wrapped about a trunnion 192 and another axis concentric
with the output gear 182. The drive means 180 includes a fly wheel
and clutch arrangement (the housing for which is indicated at 194)
which controls the output speed of the gear 182. The gear 182 is
drivingly connected to the fly wheel and clutch arrangement by
conventional gearing, the housing for which is indicated at 196.
Energy is stored in the spring 190 when the carrier 32 is manually
pushed in the direction of the arrow 88 to the point at which the
drop of blood contacts the applicator member. Then, promptly, the
person making the specimen removes his hand to permit the drive
means 180 to return the carrier 32 in the direction of the arrow
90.
I have found that I am able to obtain the proper rate of movement
of the carrier using the spring-type motor discussed generally in
FIGS. 9 and 10.
In the structure of FIGS. 9 and 10, the rack 184 is rigidly
fastened to a slider 185 which corresponds to the slider 60
discussed previously. Further, in FIGS. 9 and 10, I show
spring-loaded detent means 198 arranged to hold the carrier 32 in
its illustrated position in FIG. 9 to keep the pin 38 in the
down-turned portion 42 of the slot 34 to hold the carrier in its
inner position. Referring now to FIG. 14, it will be seen that I
have illustrated a cannula 200, cannula gripper 202 and a hose 204,
a portion 206 of which is enlarged as illustrated. In accordance
with the disclosures of my aforementioned patent applications, the
cannula 200 is inserted into a person's vein so that the blood
flows through the cannula and the hose 204. Generally, a number of
blood specimens are deposited into test tubes from the hose 204.
When the cannula 200 is removed from the vein, a blood drop of a
preferred size can be accurately positioned on the test surface of
a slide in registry with the spot 56 on the carrier simply by
placing the sharpened end of the cannula at that spot on the slide
and then gently applying pressure to the enlarged portion 206. The
pressure applied to the enlarged portion 206 will cause a drop of
blood to leave the end of the cannula 200. The size of the drop of
blood will depend on the bore size of the cannula 200. I prefer to
use a No. 21 thin wall cannula 200, and the bore size of this
particular cannula will provide a blood drop of the preferred
size.
Referring now to FIGS. 15 and 16, a comparison of the type of film
made by my apparatus with the type of film made by conventional
processes can be had. FIG. 15 is an illustration of a film made by
my apparatus. The portion of the indicated at 210 is a
longitudinally short film which is, for instance, five cells thick.
Then the film gets thinner as indicated by the area 212 which may
be, for instance two cells thick. The balance of the test area
indicated at 214 is a film which is one cell thick as desired. It
will be appreciated that more than half of the test surface
includes a film which is one cell thick. In FIG. 16, the film on
the area indicated at 216 will be quite thick. The film on the area
indicated at 218 will be progressively thinner but it will be
several cells thick. Finally, the film on the area indicated at 220
will generally be one cell thick if the conventional process is
handled properly. The length and width of the one cell thick film
provided by my apparatus 10, 10' is considerably greater than the
length and width of the film area indicated at 220 in FIG. 16.
From the above description, it will be appreciated that I have
provided an apparatus for using the apparatus which greatly
systematizes the making of blood film specimens on slides, i.e.,
the making of what is known in the medical profession as peripheral
smear specimens. When my apparatus 10 is used, the angle of
inclination of the applicator member relative to the test surface
of the slide is always the same, the speed by which the blood drop
is drawn into a film is always the same, the amount and size of the
blood drop is always the same, the pressure with which the
applicator member is held against the test surface is always the
same, the age of the blood drop deposited on the test surface when
the smear is made is always the same, and the location of the blood
drop on the slide and the length of the smear is always the same.
With respect to the age of the blood when the smear is made, I
contemplate that the blood drop will be deposited onto the test
surface of the slide just as soon as the cannula 200 is withdrawn
from the vein. As soon as the blood drop is placed on the slide,
the technician merely has to push inwardly on the carrier 32 until
it stops moving, this whole process taking place in a matter of a
very few seconds.
* * * * *