Note: Descriptions are shown in the official language in which they were submitted.
:
1~75571
The present invention is directed to a biological
testing apparatus and more specifically to an apparatus for
simultaneously transferring a plurality of individual drops of
liquid from a co~non trough to a plurality of individual
spaced apart cavities for te~ting purposes.
- It is old and well known in the art to provide a
plate having a plurality of dispensing prongs spaced thereon
in a predetermined pattern and a container having a plurality
of holes or wells spaced therein in the same predetermined
pattern. However, such prior art dispensers did not provide
any control whatsoever for the extent of penetration of the
dispensing prongs into the holes. Furthermore, it was never
; contemplated to use the plate upon which the prongs were
mounted as a cover for either a common supply of liquid or a
cover for the container having a plurality of holes therein
since the prongs depending from the plate were many times
longer th~n the depth of the holes.
, Other prior art devices contemplated the use of a
tray having a cover adapted to fit thereon in a predetermined
relation with a plurality of prongs depending from the
underside of the cover a predetermined distance into the tray.
Quantities of different metabolic agents were applied to the
prongs in various ways for insertion into a common culture
medium in the tray. Thus, the separation of the cultures
,~ during a culture study was achieved solely ~y the spacing of
the prongs and separate individual cavities were not provided
for each culture growth.
Another bacteriological titration arrangement
utilized two identical trays each having a plurality of
individual cavities formed therein in identical spaced apart
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relation. One tray was adapted tG fit on top of the other
with the cavities of the one tray disposed directly over the
cavities of the other tray. Upon puncturing the bottom of
the cavity in the upper tray the fluid therein could be
forced by air pressure through the puncture into he cavity
directly therebeneath thus eliminating the need for fluid
transfer prongs.
The present invention provides a bacteriological
testing apparatus which provides a convenient and economical
arrangement for simultaneously transferring a plurality of
individual drops of liquid from a common tray to respective
individual cavities in a second tray.
The present invention provides a bacteriological
testing apparatus wherein a common cover and fluid transfer
member is provided which will cooperate with trays having
identical external dimensions and fluid compartments of
equal depth to accurately control the relation of the fluid
transfer member to the liquid in the compartments.
The present invention provides a bacteriological
testin~ apparatus comprised of first and second substantially
rectilinear trays having identical external dimensions
including an outwardly extending flange about the periphery of
the base of each tray and a cover member having a plurality of
depending prongs spaced apart in a predetermined pattern on
the under surface thereof and a depending peripheral flange
adapted to cooperate with the flange on a respective tray to
accurately position the prongs relative to each tray and at
the sam~ time keeping the under surrace from which the prongs
extend from contacting the top surface of th~ trays, said
first tray having a single substantially rectilinear fluid
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receiving trough and said second tray having a plurality of
individual cavities having a depth e~ual to the depth of said
trough and being spaced in a predetermined pattern identical
to the spacing of said prongs. The end of each prong may be
roughened and/or provided with a concave cavity to facilitate
the transfer of a drop of liquid from one tray to the other.
The side walls of each tray and the depending flange on said
cover slope outwardly to provide a good fit between the cover
and each tray so that the li~uid in the trough of the first
tray may be protected by the cover until such time as it is
desired to transfer a plurali~y of drops of li~uid to the
; cavities of the second tray and thereafter either provide
protection for the culture growth in each cavity by means of
the same coYer membex which was used to inoculate the
substance in each cavity of the second tray or be returned to
the first tray for safe disposal of its contents if other
means o~ sealing the second tray are used.
; In addition, both trays have keyed female slots or
narrow openings in their vertical outside walls which mate
, 20 with male keys in the inside surfaces of the vertical walls of
the cover that aid in the proper orientation of its prongs
before the cover can be seated on the trays, thereby helping
, to avoid the prongs and their liquid drops from contacting th~ top surfaces of the trays.
In the drawings:
- Figure 1 is an exploded view of the cover and first
tray having the com~lon trough with portions of the cover
broken away to expose the fluid transfer prongs;
Pigure 2 is a sectional view of the cover and tray
of Figure ~ along the lines 2-2;
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Figure 3 is a view similar to Figure 1 showing the
cover and second tray having the individual cavities in spaced
apart relation;
Figure 4 is a sectional view of the cover and second
tray taken along the lines 4-4 of Figure 3; and
Figure 5 is a partial sectional view of the cover
and fluid transfer prongs showing the detail thereof.
In Figures 1 and 2, the cover 10 is illustrated in
spaced relation to a first tray member 20. The cover 10 is
provided with a flat rectangular upper surface 12 and four
depending side walls 14 which slope outwardly as best seen in
Figure 2. A plurality of identical prongs 16 extend
downwardly from the upper surface 12 and the lower end of
each prong is formed with a concave recess 18 to facilitate
the transfer of a single drop of liquid on the tip of the
prong after the prongs have been dipped into a liquid supply.
Each of the. prongs 16 are spaced from each other in a
predetermined pattern. According to the present example, a
total of thirty-two prongs 16 are provided in four rows with
eight prongs in each row so that the prongs will be equally
spaced from each other in a rectangular pattern.
The tray 20 is provided with a flat rectangular
upper surface 22 with four side walls 24 depending therefrom
and sloped outwardly as best seen in Figure 2. A peripheral
flange 26 extends completely about the lower edge of the four
walls 24 and the center portion of the upper surface 22 is
provided with a rectangular depression or trough 28. The
rectangular trough 28 is sized so as to receive the rectangular
array of prongs 16 which depend from the under surface of the
cover 10. The slope of the side walls 24 of the tray 20 mat~h
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the slope of the side walls 14 of the cover 10 so that the
cover 10 will fit easily, yet closely, over the tray 20.
The bottom edges of the side walls 14 of the cover 10 rest
; on the flange 26 so that the ends of the prongs 16 will be
spaced in close proximity to the bottom of the trough 28.
~he second tray 30 is dimensioned identical to the
first tray 20 insofar as the length, width and height of the
tray is concerned. The tray 30 is provided with a flat upper
surface 32 downwardly and outwardly sloping side walls 34
and a peripheral flange 36 disposed about the lower edge of
the side walls. The upper surface 32 of the second tray 30
is provide~ with a plurality of cavities 38 which are
disposed in an array identical to the array of prongs 16 so
that when the cover 10 is fitted over the second tray 30 with
the lower edge of the side walls 14 resting on the flange 36,
the prongs 16 will each be disposed in a respective cavity 38
i with the lower ends of the prongs spaced in close proximity
to the bottom of the cavities. The depth of the cavities 38
is identical to the depth of the trough 28 in the first ~ray
20. The cover 10 is provided with a plura`lity of keys 40
and each tray 20 and 30 is provided with complementary
grooves in the side walls so that the cover will only fit on
a specific orientation.
Each of the three components of the testing kit
can be formed of any suitable plastic material, such as
polystyrene or the like, and the thickness of the plastic need
only be great enough to impart some shape retaining rigidity
to the various comronents. Thus, the three components of the
kit can be produced rather ine~pensively so that the kit can
be disposed of after a single use. ~y providing the three
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components with identically sloping side walls, the three
components can be nested and enclosed in an overwrap to
amintain the sterile condition of the components prior to
use. In the nested arrangement, the cover 10 can fit
completely over the first tray 20 and the first tray 20 can
be partially nested over the second tray 30 inasmuch as the
depth of the trough 28 is less than the overall height of
the tray 20.
In use, the trough 28 in the tray 20 would contain
a bacterial culture medium. By placing the cover 10 over the
first tray 20 so that the lower edges of the side walls 14
rest on the flange 26, the prongs 16 will dip down into the
bacterial culture medium. As the cover is lifted, a drop of
the bacterial culture medium will be carried by each
projection or prong for transfer to the individual cavities
of the microtiter tray 30 which have been previously filled
with a specified amount of a biological testing medium.
Although it is possible to construct the three compoents of
the testing kit from a material which can withstand repeated
autoclaving for reuse, it is preferred to produce the
components by an inexpensive injection molding process and
gas sterili~e the components initially so that they can be
disposed of after use, thereby avoiding any possible
contamination of subsequent testing operations. The present
construction of the components according to the present
invention also provides additional safety for the user in
handling dangerous bacterial growths. The sides of the cover
protect the user from coming into contact with the pick-up
prongs and the growth carried thereby. ~s mentioned
previously, the lower end of each prong is provided with a
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concave recess to assist in holding a drop of the growth on
the end of the prong. The ends of the prongs could also be
roughened to aid in holding a drop of fluid thereon.
It is also possible to compartmentalize the trough
20 by adding vertical cross members so that more of the
medium may be transferred simultaneously by the respective
prongs that correspond to the compartment.
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