Refill pack for pipette tip racks

A refill pack for storing and dispensing pipette tips into an empty tip rack. The refill rack comprises a hand-gripable carrier for an array of pipette tips releasably secured relative to the carrier such that after hand positioning the array of tips on the empty tip rack, the carrier may be released from the tips which are then free to be seated on a lower end of a pipette and removed from the tip rack.

FIELD OF INVENTION 
The present invention relates to the refilling of pipette tip racks and, 
more particularly to a disposable refill pack of pipette tips for reusable 
pipette tip racks. 
BACKGROUND OF THE INVENTION 
It is the function of pipette tip racks to organize disposable pipette tips 
in a manner for convenient tip placement on a pipette. Such racks 
generally comprise a base with vertical sides joined at contiguous edges 
and containing supports for a rigid horizontal tray or support plate 
containing an array of holes for vertically receiving and supporting a 
horizontally spaced array of pipette tips. The pipette tips are held 
vertically in the array for ease of access by a pipette tip user. In this 
regard, the pipette tip user simply moves a hand-holdable pipette over the 
rack and lowers a distal end of the pipette into a proximal or upper end 
of a vertically oriented tip and presses down to affix the tip to the 
pipette. A similar operation is followed by the user when connecting a 
plurality of tips to a multiple tip pipette. U.S. Pat. No. 4,676,377 
describes a conventional pipette tip rack of the type just described, and 
U.S. Pat. No. 4,779,467 describes a multiple tip pipette. 
Once all tips are dispensed from the tip rack, the rack may be discarded or 
reloaded with a new supply of pipette tips. The reloading of disposable 
pipette tips into such tip racks in a rapid, convenient manner is 
important to pipette users. Further, any packaging containing pipette tips 
and for use in loading pipette tips into a tip rack should arrange the 
pipette tips in a manner to accommodate direct dispensing of the tips into 
standard tip rack arrangements. Moreover, it is important that such 
packaging protect the disposable pipette tips from damage and 
contamination during shipping, handling and storage and provide for 
sterilization by autoclaving or irradiation of the pipette tips. Still 
further, when plastic materials are utilized for such packaging, it is 
particularly important to the preservation of our environment (1) that the 
plastic material be recyclable and (2) that the packaging structure be 
thin, lightweight and of low mass to minimize the amount of 
non-biodegradable disposable material from such packaging. Furthermore, 
there is a need for refill packs for manually reloading reusable pipette 
tip racks with filter containing pipette tips such as the FilterPro of the 
Rainin Instrument Co., Inc., assignee of the present invention, or, such 
as the filter devices described in U.S. Pat. No. 5,156,811, assigned to 
Continental Laboratory Products, Inc. of San Diego, Calif. 
Prior packaging used for stacks of pipette tip racks and for pipette tips 
for reloading empty pipette tip racks do not satisfy such requirements. 
For example, U.S. Pat. No. 3,853,217 describes a stack of stand-alone 
pipette tip racks, referred to in the patent as "trays". Each tray 
comprises a horizontally oriented rectangular support. The horizontal 
support contains transverse stiffening ribs. Each rib extends above the 
horizontal support and terminates in marginal vertical sides. The sides 
extend above and below the horizontal support and connect at their 
contiguous edges to form a skirt. The skirt extends below distal end 
portions of vertical pipette tips contained in a honeycomb array of 
openings in the horizontal surface. A shoulder is formed around the skirt 
so as to accept and support an identical upper tray to rest a lowermost 
edge of its skirt for stacking of the trays. The shoulder thereby spaces 
the upper tray so as to allow the distal end portion of the pipette tips 
in the upper tray to extend into the open proximal end of the pipette tips 
in the lower tray. Concentric positioning of the upper tips in the lower 
tips permits a nested stacking of multiple trays. A cover encloses the 
topmost tray in the stack. Tape is used to secure the cover and stacked 
trays; applied to fasten the cover and trays along common sides. Nested 
stacks of the trays with a cover are enclosed within a snug carton for 
shipping and storage. Additionally, folded sleeves are included in the 
shipping carton for covering a tray removed from the stack. The carton is 
provided with a pipette tip extractor for collecting used tips in the 
shipping carton. The trays are structurally rigid and with sufficient 
material thickness to be self supporting. The rigid trays are used 
individually and stored as stacked. 
In use, the stacked trays with the cover taped in place are removed from 
the shipping carton. Individual trays are removed from the bottom of the 
stack by severing the tape attaching the lowest tray, leaving the upper 
trays attached and enclosed until the next bottom tray is to be used. The 
pipette tips are accessed individually from the tray, since the honeycomb 
arrangement does not accommodate multiple tip pipettes. Used pipette tips 
are disposed of in the shipping carton, using the tip extractor included. 
As each tray is emptied, it is discarded. Since the trays are intended for 
stand-alone use, their structure is necessarily heavy, with thick 
stiffening sections, containing a significant amount of plastic. 
Therefore, the heavy trays represent a significant environmental disposal 
problem. Further, the nesting of the trays with upper pipette tips 
extending into lower tips, precludes the use of the package of U.S. Pat. 
No. 3,853,217 for storage and dispensing of filter containing pipette 
tips. 
In U.S. Pat. No. 3,937,322, a package containing a stack of trays of 
pipette tips is disclosed. Each tray comprises a horizontal rectangular 
support with an array of openings. The openings accept distal end portions 
of pipette tips and maintain their longitudinal axes in a vertical 
orientation. The trays are stacked in a carton by telescoping the pipette 
tips carried by an upper tray into the open upper ends of the pipette tips 
carried by the next lower tray and by resting a horizontal support lower 
surface of the upper tray on the upper edge of the pipette tips in the 
next lower tray. The lowermost tray in the stack is supported on a tray 
support extending vertically from a bottom of the carton. Also attached to 
the carton is a pipette tip extractor. 
In use, the carton is opened at the top and uppermost pipette tip trays are 
exposed. The pipette tips are accessed from the open top of the carton and 
individually loaded onto pipettes. This is accomplished by pressing an end 
of a pipette into a tip to seat the tip thereon and then by removing the 
loaded pipette from the carton. When all the pipette tips on the uppermost 
tray have been thus dispensed from the tray, the tray is discarded, 
exposing the tips in the tray below. The pipette tip extractor is 
installed in a wall of the carton and permits a used tip to be extracted 
from the pipette and dropped into the carton without contact with the 
user. The carton is then used for disposal of used tips. 
As described, the container of U.S. Pat. No. 3,937,322 is characterized by 
a number of shortcomings. Because of the telescoping of the pipette tips 
in the stack of trays, it is not possible to use the packaging of the '322 
patent for the storage and dispensing of filter containing tips. Further, 
for one of the contained pipette tips to be accessible to a user for 
reloading of a pipette, substantially all the contained pipette tips are 
exposed to the atmosphere and hence subject to possible contamination. 
Finally, each tray is supported on the tops of the pipette tips in the 
next lower tray. Unless the trays and the bottom tray support are formed 
of relatively heavy, rigid plastic or equivalent material, the downward 
pressing of the pipette in loading a tip onto the shaft of a pipette will 
produce an undesired downward bowing of the trays. The bowing of the tray 
makes it difficult to insert a pipette tip onto the end of a pipette 
shaft. In the case of a multiple-tip pipette, only a small amount of 
bowing is required to prevent a user from being able to insert pipette 
tips simultaneously onto all shafts of the multiple-tip pipette simply by 
pressing down on the pipette. Rather, if the tray bows, a user must (i) 
check each tip individually in order to assure that all tips are properly 
secured to each pipette shaft and (ii) secure any loose tips individually 
by hand. With a heavier, more rigid rack support, such bowing will not 
occur. However, if the trays and the bottom tray support are formed of a 
heavy rigid plastic material to prevent such undesired bowing during the 
loading of pipettes, then the disposal of such trays will present an 
undesired increase in the disposal of non-biodegradable materials. 
Prior commercially available packaging of stacks of nested pipette tip 
racks similar to the packaging disclosed by the U.S. Pat. No. 3,853,217 
and possessing all the disadvantages thereof is represented by the RBR 
Packaging of Bio-Rad Laboratories, Inc. of Richmond, Calif. TBR Packaging 
comprising a stack of separate racks is also available from Bio-Rad 
Laboratories, Inc. In addition, USA/Scientific Plastics of Ocala, Fla. 
markets a RE-K RACK comprising a reusable pipette tip rack, designed to 
accept RE-K Tray Cartridges preloaded with 192 pipette tips per tray. 
Once a tray is empty, it is simply removed from the rack and discarded and 
another tray cartridge inserted in its place. The RE-K Tray Cartridges 
are formed of a rigid, relatively heavy plastic construction and, but for 
the transverse ribs, resemble and possess the disadvantages of the trays 
disclosed in U.S. Pat. No. 3,853,217. Such RE-K tray cartridges are 
available in shrink-wrapped stacks of 5 trays of 192 tips each. 
From the foregoing, it should be appreciated that prior packages for 
pipette tip racks and trays do not satisfy the previously stated desired 
requirements for packaging for reloading of disposable pipette tips into 
reusable tip racks. Thus, there is a continuing need for such packaging 
which is satisfied by this present invention. 
SUMMARY OF THE INVENTION 
In its most basic form, the present invention provides a simple, light 
weight, low cost and disposable or recyclable refill pack for reusable 
pipette tip racks in which pipette tips are contained with their 
longitudinal axes vertically positioned in a horizontally spaced pattern 
or array. The refill pack comprises (i) a horizontally extending pipette 
tip organizing and support plate, (ii) a light weight hand-gripable 
support plate carrier, and (iii) manually releasable means for dispensing 
pipette tips from the refill pack into an empty tip rack. The support 
plate includes an array of holes for vertically receiving and organizing 
pipette tips in a desired pattern for deposit into and containment within 
an empty tip rack. Distal end portions of the pipette tips extend 
vertically through the holes on one side of the support plate while 
proximal end portions of the pipette tips are supported by the plate on an 
opposite side thereof. The carrier is secured to the support plate and 
enables a user to manually move and position the support plate over an 
empty tip rack while the support plate maintains the horizontal spacing 
and vertical orientation of the pipette tips within the refill pack ready 
for dispensing into the tip rack upon a release of the tips from the 
refill pack. Thus, in use, a user hand grips the carrier and lifts and 
moves the array of pipette tips over and down onto the top of an empty tip 
rack until the distal ends of the pipette tips seat in an array of holes 
in a support tray of the tip rack. The user then releases the array of 
tips from the carrier readying the tips for seating on and pick up by a 
lower end of a pipette. 
Preferred embodiments are presented setting forth details referred to and 
illustrated in the drawings described below. The variations of the 
invention hereinafter described may be packaged separately or with a 
pipette tip rack.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention provides a novel refill pack of disposable pipette 
tips for reusable pipette tip racks and may take any of a multiplicity of 
forms within the claims hereafter presented. Each embodiment may include 
or exclude a tip rack as part of the refill pack. Additionally, the 
materials for use in the present invention may be selected as appropriate 
for sterilization by autoclaving or irradiation and to permit recycling 
for minimizing detrimental environmental impact. 
More particularly, a simplified form of a single array refill pack 10 is 
shown in FIG. 1a and comprises a pipette tip organizing means 14 for an 
array of pipette tips 12 in combination with a hand gripable carrier 16 
for the organizing means 14. 
As illustrated, the organizing means 14 comprises a semi-rigid plastic 
support plate 18 having an array of holes 20 for (i) receiving distal end 
portions 22 of the pipette tips 12 and (ii) organizing the pipette tips 12 
into a horizontally spaced array. The array of pipette tips 12, which may 
comprise filter containing pipette tips, has distal end portions 22 
extending perpendicularly through the holes 20 in the support plate 18 and 
proximal end portions 24 extending perpendicularly from the opposite 
surface of the support plate 18. 
As also illustrated in the embodiment of FIG. 1a, the carrier 16 comprises 
a cover 26 secured by releasable means 28 to the support plate 18. The 
illustrated cover 26 comprises an alignment plate 33 which rests on and 
confines the proximal end portions 24 of the pipette tips 12 in 
combination with the support plate 18. 
The releasable means 28 of FIG. 1a comprises a tape 30 of sufficient 
vertical dimension and length to extend between and around and to 
adhesively, thermally or mechanically attach to marginal edges of the 
support plate 18 comprising the organizing means 14 and marginal edges of 
the alignment plate 33 comprising the carrier 16. 
To protect the distal end portions 22 of the array of pipette tips 12 and 
to complete the packaging for the refill pack 10, the refill pack may be 
enclosed by shrink wrap or within a pouch or other container or box of a 
thin light weight recyclable plastic or cardboard material. Then, in use, 
the refill pack is removed from the shrink wrap, pouch or box. Next, the 
user of the refill pack grips the alignment plate 33 comprising the 
carrier 16, moves the pack 10 over the top of any empty tip rack, and 
lowers the carrier to insert the distal end portions of the array of 
pipette tips 12 into the open top of the rack. He then releases the tape 
30 to separate the carrier 16 from the array of pipette tips 12 as well as 
the support plate 18 which remain in the tip rack. Finally, the alignment 
plate 33 comprising the carrier is removed and may be recycled, as may the 
support plate after all of the pipette tips are dispensed from the tip 
rack. 
An alternate form of the refill pack 10 is shown in FIG. 1b. As 
illustrated, instead of comprising a length of tape, the releasable means 
28 comprises plastic or metal spring clips 32 or other spring attachment 
means, releasably securing the carrier 16 and the support plate 18. In the 
illustrated alternative, the alignment plate 33 includes a downwardly 
extending marginal channel 34a formed so as to accept the spring clip 32 
with its uppermost surface flush with the upper surface of the alignment 
plate 33. Similarly, to accept the lower portion of the spring clip 32, 
the support plate 18 contains an upwardly extending marginal channel 34b 
formed so as to retain the spring clip lowermost surface flush with the 
lower surface of the support plate 18. 
In addition, in the alternative form of the refill pack illustrated in FIG. 
1b, an array of frusto-conical projections 36 extend downwardly from a 
bottom of the alignment plate 33. The array of projections 36 correspond 
to and align vertically with the array of holes in the support plate 18 
and define indexing means extending into and laterally constraining 
proximal end portions 24 of pipette tips 12 to maintain the longitudinal 
axes of the pipette tips 12 in a vertical orientation. 
In use, the spring clips 32 releasably secure the support plate 18 relative 
to the alignment plate 33 whereby a manual positioning of the support 
plate 18 over a pipette tip rack 38 with the distal end portions 22 of the 
pipette tips 12 extending into the pipette tip rack 38 followed by a 
release of the spring clips and removal of the alignment plate 33 affects 
a refilling of the pipette tip rack. 
From the foregoing description of the embodiments illustrated in FIGS. 1a 
and 1b, it should be appreciated that the present invention may take many 
various forms. For example, the hand grippable carrier described above may 
comprise a tubular housing or carrier having an open lower end and an open 
upper end. Such tubular carriers for supporting the organizing or support 
plate, and a plurality of carrier plates each supporting an array of 
pipette tips are described by way of example in the parent patent 
application, now U.S. Pat. No. 5,441,702, which is hereby incorporated by 
reference. 
Specifically, referring to the U.S. Pat. No. 5,441,702, FIG. 10 thereof 
depicts a stacked multiple array refill pack comprising a vertical tubular 
container formed of a light weight plastic material and housing an 
organizing plate and a plurality of carrier plates. The organizing plate 
and carrier plates each include an identical array of holes corresponding 
to the array of holes in an organizing tray of an empty pipette tip rack. 
Arrays of pipette tips are supported in the holes and each of the 
organizing plate and carrier plates. 
As shown in FIG. 10 of the patent, when the carrier is positioned over an 
empty pipette tip rack, distal end portions of a lowermost array of 
pipette tips supported by the organizing plate extend into corresponding 
holes in the tray of the tip rack. Also, as shown in FIG. 10 of the 
patent, corresponding pipette tips in the array carried by the lowermost 
carrier plate telescope into proximal end portions of the pipette tips 
carried by the organizing plate. Similarly, the distal end portions of the 
pipettes of each of the arrays supported by each of the other carrier 
plates telescope into proximal end portions of the corresponding pipette 
tips supported by the next lower carrier plate. 
To refill the empty tip rack, a user simply places the carrier over the tip 
rack and presses on a push plate bearing on the proximal end of the 
pipette tips carried by the uppermost carrier plate. This forces the 
stacked arrays of telescoping pipette tips and their associated carrier 
plates downwardly within the carrier. This, in turn and causes the 
organizing plate to move over inward projections in opposing side walls of 
the carrier adjacent the lower open end thereof to cause the adjacent 
portions of the side walls of the carrier to flex slightly outward. This 
releases the organizing plate and the array of pipette tips supported 
thereby downwardly onto the top of the organizing tray in the pipette tip 
rack to refill the tip rack. After the organizing plate passes the 
projections, the side walls of the carrier return to their normal position 
and the projections then engage the under side of the lowermost carrier 
plate to support the stack of arrays of pipette tips and carrier plates 
within the carrier, the under side of each of the carrier plates above the 
lowermost carrier plates resting on the proximal end of the pipette tips 
supported by the next lower carrier plate. 
Each of FIGS. 2-6 and 7a, 7b, and 7c diagrammatically depict alternative 
embodiments of such a stacked multiple array refill pack including 
different release mechanisms for the organizing plate and carrier plates 
in dispensing arrays of pipette tips from the carrier into empty pipette 
tip racks. Each such alternative embodiment comprises cooperative means on 
the organizing plate and the carrier for releasably securing the 
organizing plate and subsequently each individual carrier plate in the 
carrier for release with the plurality of pipette tips supported thereby 
from the carrier through the open bottom of the carrier and into an empty 
pipette tip rack upon an actuation of the cooperative means by a user of 
the refill pack. 
In particular, FIG. 2 diagrammatically depicts a refill pack 38 over an 
empty pipette tip rack 40. The refill pack 38 comprises a tubular carrier 
42 having a lower open end 44 and containing an organizing plate 46 and a 
plurality of identical carrier plates 48, each plate having an array of 
holes 50 (see FIG. 6) receiving a plurality of pipette tips 52. The arrays 
of holes 50 in each of the plates (46, 48) match an array of holes 54 in 
the support tray 56 of the pipette tip rack 40 such that the distal end of 
each pipette tip 48 in the refill pack 38 telescopes into an open proximal 
end of a next lower pipette tip 48 carried by the next lower plate. As 
depicted, opposing inner side walls 58 and 60 of the tubular carrier 42 
include inwardly facing projections 62 and 64 adjacent the lower open end 
44 of the carrier 42. The projections 62 and 64 are adapted to engage 
outwardly extending portions of vertically extending arms 66 and 68 
respectively. The arms 66 and 68 extend from opposing sides of the 
organizing plate 46 as depicted. Thus, as represented, the projections 62 
and 64 horizontially support the organizing plant over the lower open end 
44 of the carrier 42. Due to the telescoping structure of the carrier 
plates and arrays of pipette tips supported thereby, the projections 62 
and 64 also provide vertical support for each of the carrier plates and 
pipette tip arrays. In this regard as in the embodiment of FIG. 10 of U.S. 
Pat. No. 5,441,702, each carrier plate rests on top of the proximal end of 
the tips in the array supported by the next lower carrier or organizing 
plate. 
In the embodiment of FIG. 2, the arms 66 and 68 are moveable by being 
either deformable or resilient such that in response to a downward force 
applied by a user pressing on a push plate 70 resting on the uppermost 
array of tips, the arms 66 and 68 of the organizing plate flex, bend or 
move inwardly to pass over the projections 62, 64 on the carrier 42 to 
allow the organizing plate 46 and the plurality of pipette tips 52 
supported thereby to drop through the lower open end 44 of the carrier 42 
and onto the tray 56 of the empty pipette tip rack 40. Since, as 
illustrated, each carrier plate 48 is identical in structure to the 
organizing plate 46, (each including arms 66 and 68), with such downward 
movement, the arms of the lowermost carrier plate engage the projection 
62, 64 readying the array of pipette tips supported thereby for dispensing 
into the same or a different empty pipette tip rack in response to further 
downward force applied to the push plate 70. 
In FIGS. 3 through 6 and 7a, 7b, 7c, embodiments of a refill pack similar 
to FIG. 2 but including latch type release mechanisms are illustrated over 
empty pipette tip racks. For example, in FIG. 3, the tubular carrier 42 
includes user operable release latches 72 and 74 on the opposing sidewalls 
58 and 60 instead of the projections 62, 64 and arms 66, 68 defining 
cooperative release means for the organizing and carrier plates 46, 48. 
Each latch includes an inwardly extending latch member 76 supported by a 
hinge 78 to an associated one of the sidewalls of the carrier 42 for 
engaging an under surface of the organizing plate 46 as illustrated. Upon 
manual rotating of the members 76, (as depicted by the arrows), the 
latches release from the under surface of the organizing plate allowing 
the plate and the array of pipette tips supported thereby to drop through 
the lower open end 44 of the carrier 42 and into an empty rack 40. After 
reloading of the tip rack, the latches are returned to their original 
position to support the lowermost carrier plate 48 and the array of 
pipette tips 52 supported thereby. 
The alternative embodiment of FIG. 4 is similar to FIG. 3 except that 
instead of including hinges, the latches 72 and 74 each include an 
outwardly extending pull tab 80 connected to inwardly extending projection 
82 in a sidewall (58, 60) of the carrier 42 for engaging the underside of 
the organizing plate 46 as illustrated. To release the latches of FIG. 4, 
the user simply pulls outwardly on the tabs 80 to outwardly flex opposing 
sidewalls of the carrier allowing the organizing plate and the array of 
tips 52 supported thereby to drop through the lower open end 44 of the 
carrier into the empty pipette tip rack 40. A release of the pull tabs 80 
automatically returns the projections 82 under the lowermost carrier plate 
48 readying the refill pack for subsequent operation as described above to 
release the lowermost carrier plate and the array of pipette tips carried 
thereby into another empty pipette tip rack. 
In the alternative embodiments of FIGS. 5 and 6, the latches 72 and 74 are 
diagrammatically illustrated as comprising slide members 84 and 86 
supported in opposing vertically extending slots 88 in sidewalls 58 and 60 
of the tubular carrier. Each slide member carries two or more protrusions 
90 extending inwardly within the carrier 42 to engage an underside of an 
horizontially support the organizing plate 46 within the carrier over the 
lower open end 44. Front and back marginal edges of the organizing plate 
46 include matching horizontally spaced vertical slots 92 for aligning 
with and vertically receiving to projections 90. Thus, when the slide 
members 84 and 86 are positioned as shown in FIG. 5, the protrusions 
engage the under surface of the organizing plate 46 to secure the 
organizing plate and the stack of carrier plates 46 within the carrier 42. 
Then, when it is desired to release the organizing plate 46 and the array 
of tips 52 supported thereby, a user simply slides the slide members to 
move the protrusions 90 into alignment with the slots 92 in the side of 
the organizing plate to allow the organizing plate to move vertically 
downward through the open bottom 44 of the carrier 42 to deposit the array 
of pipette tips 52 supported thereby in the empty pipette tip rack 40 
located below the tubular carrier. After release of the organizing plate 
from the carrier 42, the user slides the slide members back to the 
position shown in FIG. 5 to secure the lowermost carrier plate 48 within 
the carrier 42 for subsequent release in the same manner as described for 
the organizing plate. 
Finally, FIGS. 7a, 7b and 7c illustrate a similar refill pack wherein the 
latches 72 and 74 each comprise a resilient latch are formed in and 
extending inwardly from a sidewall (58, 60) of the tubular carrier 42 for 
engaging and vertically supporting the under side of the organizing plate 
46 contained within the carrier. This is most clearly illustrated in FIG. 
7a. The arm 94 of each latch extends upwardly and inwardly from its 
associated sidewall and is designed to engage an upwardly extending side 
of the empty pipette tip rack 40 when the carrier 42 is positioned 
thereover, as shown most clearly in FIG. 7b. As the vertical side of the 
tip rack 40 engages the arm, the arm moves upwardly and outwardly 
effecting a release of the organizing plate and the array of pipette tips 
52 supported thereby downward through the open bottom 44 of the carrier 
and onto the tray 56 of the tip rack as illustrated in FIG. 6b. Then, when 
the tubular carrier 42 is moved upwardly as shown in FIG. 7c, the arm 94 
of each latch returns to its initial horizontal position engaging the 
underside of the lowermost carrier plate allowing the carrier 42 to lift 
the stack of carrier plates and arrays of pipette tips with the refill 
pack from the pipette tip rack for placement over another empty pipette 
tip rack in order that the refill operation just described and illustrated 
in FIG. 7a, 7b, and 7c may be repeated. 
In view of the foregoing alternatives, it should be clear that the present 
invention is to be limited in scope only by the following claims.