US2937787A - Pipette dispenser - Google Patents

Description

y 1960 R. o. TAYLOR ETAL 2,93

PIPETTE DISPENSER Filed Jui :51, 1956 2 Sheets-Sheet 1 &

Q Q g INVENTORS RICHARD 0. TAYLOR EDWARD s. KLINE 74 R. O. TAYLOR ET AL P'IPETTE DISPENSER 2 Sheets-Sheet 2 Filed July 31, 1956 INVENTORS RICHARD O. TAYLOR EDWARD S. KL/NE BY A77'0fi/VE/S United States Patent O PIPETTE DISPENSER Richard 0. Taylor, Greenbelt, Md., and Edward S. Kline, Falls Church, Va., assignors to the United States of America as represented by the Secretary of the Army Filed July 31, 1956, Ser. No. 601,329

3 Claims. (Cl. 221-248) (Granted under Title 35, US. Code (1952), sec.'266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.

It being frequently essential for pipettes to be sterile for use, and substantial numbers being required often, it is standard procedure for sterilizing such instruments to wrap them in a special paper and place them on a rack within an autoclave. To maintain the pipettes in the sterile condition, they would have to be kept within the autoclave or within the paper until ready for use. Each time a single pipette was needed either the autoclave would be opened and the single pipette withdrawn, or else the paper would have to be unwrapped. The opening of the autoclave was inconvenient and exposed other instruments left in it to contamination by air. In addition, opening the autoclave required the use of both hands, which itself is inconvenient and time consuming in some laboratory procedures. Unwrapping the paper covering also involved use of both hands, and more importantly, incurred likelihood of loss of sterility.

From the foregoing, it may be said to be an object of the present invention to provide apparatus which dispenses an individual pipette under sterile conditions.

Another object of this invention is to provide a dispenser of pipettes which is convenient to operate.

A further object of this invention is to provide apparatus which will deliver individual pipettes in a sterile condition after storage. v

A still further object of this invention is to provide a dispenser of pipettes that may be operated by one hand.

. Another object of this invention is to provide a pipette dispenser in which a number of pipettes may be sterilized simultaneously.

A still further object of this invention is to provide apparatus which will store and maintain pipettes in a sterile condition.

Other objects of this invention will appear as the description proceeds, and the features of novelty will be pointed out in particularity in the appended claims.

In the drawings:

Fig. l is a perspective view of the complete pipette dispenser with the cover closed;

Fig. 2 is a side view of the pipette dispenser showing in outline a pipette ready for delivery and with the closure door outlined in its open position;

Fig. 3 is an end view of the discharge end of the dispenser illustrating the pipette closure door, this end being labeled a in Fig. 2;

Fig. 4 is an end view of the opposite, or plunger end of the dispenser, this end being labeled b in Fig. 2;

Fig. 5 is a transverse vertical sectional view ofv the dispenser, the view being taken along the line 5 5 of Fig. 2 looking in the direction of the arrows;

Fig. 6 is a fragmentary sectional view of the lower left hand end of the dispenser illustrated in Fig. 2, the view being indicated by the line 6-6 of Fig. 3;

Fig. 7 is a vertical sectional longitudinal view ofthe dispenser, the view being taken generally along the longitudinal center line as shown by the line 7--7 of Fig. 3;.and

Fig. 8 is a top fragmentary sectional view of the right hand end of the dispenser as viewed in Fig. 7, the view being along the line 88 of Fig. 7, looking in the direction of the arrows.

In Fig. 1 the entire pipette dispenser is shown with cover 1 closing the body of a hopper-like dispenser receptacle formed by side walls 4 and 4 and the front wall 3 and back wall 5. Cover 1, as well as all other parts, is preferably composed of a non-corrosive metal such as aluminum. Cover 1, shown with reinforcing integral peripheral flange 2, frictionally fits snugly over the receptacle, yet is not air-tight. Preferably, cover 1 comes down over the top of the hopper for a substantial distance, for example, one inch. The design of the cover is a studied result of the use of the dispenser. For sterilization, the dispenser is placed in an autoclave, and for this purpose cover 1 cannot be steam-tight. After removal from the autoclave, the dispenser may be stored in the open air. The cover should be reasonably tightfitting and provide an ascending air passage only, so that dust and germs will not enter the dispenser and contaminate the sterile pipettes.

Front 3 and back 5 walls extend equally below the sidewalls of the hopper and are bent at their bottoms to provide flanged support for the dispenser as shown at 3 and 5. Other supporting means may also be utilized. The side walls 4 and 4, which for convenience may be made of one continuous metal sheet, have substantially straight and parallel upper portions for receiving the cover 1, 1

from which upper portions the side walls of the hopper converge inwardly equally and downwardly to a radial junction having a curvature and width approximately corresponding to similar values of the pipettes being dispensed so that one at a time of such pipettes is received at this juncture.

To perform the two operating functions of the dispensing apparatus, plunger 11 is moved inwardly toward the end wall 3. Simultaneously, the dispenser door 18 is opened by engagement therewith of long plunger rod 8,

. then the pipette which is in the juncture between the side walls is pushed partially through the opened door by movement of the short plunger rod 16 against the pipette, so that the end of the pipette does not contact against the door 18 prior to opening thereof, thereby avoiding any likelihood of breaking the pipette. Thus, an individual sterile pipette is ejected. Plunger 11 is the connecting bridge between the two rods 8 and 16 which perform the opening of the door closure and the pipette ejectment, respectively. Rods 8 and 16 both pass through rod guide 10 which, by means of flange 12 and screws 15, is connected to front wall 3. Rod 8, which opens the closure door, is positioned in a channel in rod guide 10, through an aperture in front wall 3, along side of and substantially parallel to the slanting side wall 4', through guide 6, and finally through an aperture in back wall 5, so as to strike against door 18 when plunger 11 is moved toward front wall 3. In order to return plunger 11 and its connected rods 8 and 16 to their normal positions, a circular spring 13 is positioned around rod 8 in that portion of rod 8 between plunger 11 and rod guide 10. Rod 8 is limited in its movement by stop 20 secured thereto.

The nearly simultaneous ejectment of the pipette and opening of the dispenser closure door may be seen more clearly by reference to Fig. 2, a side view of the dispenser. The closure opening rod 8 is positioned so as to apply pressure onto door 18 a moment previous to the ejectment of the pipettes through the dispenser side orifice 24. This arrangement -.is dictated by the object of having rod 8 apply the opening pressure onto door 18 and avoiding pipette 23 applying such pressure. If the door opening pressure were supplied by pipette 23, the pipette might break or become contaminated.

An imortant feature of this invention is the maintenance of door 18 in its open position after partial ejectment of pipette 23 and until pipette 23 is fully removed from out of the dispenser. This feature enables numerous pipettes to be individually removed from the dispenser, an operator having to use only one hand. In this operation, plunger 11 is moved toward front wall 3, compressing spring 13. Rods 8 and 16 simultaneously slide in the direction from front wall 3 to back wall 5. Rod 8 pushes against door 18 raising the door from its closed position over orifice 24 and flat against back wall to its open position at some angle approaching the perpendicular to wall 5. Simultaneously, rod 16 pushes against the end of pipette 23 thereby moving the pipette outwardly through orifice 24. When plunger 11 is pushed all the way in until stop 20 contacts wall 5, the pipette 23 will protrude about one-half to one inch beyond back wall 5. This protruded length will support closure 18 and maintain it in its open position until the pipette is completely removed from the hopper, which is done by grasping the projecting end of the pipette with one hand or a suitable instrument, and pulling the pipette completely from the hopper, whereupon the weight 19 closes the door 18 without exposure of the remaining pipettes in the hopper to contamination from the surrounding air. Plunger 11 is next released, whereupon spring 13 causes plunger 11 and rods 8, 16 to move to return to their original positions.

The closure mechanism may be seen more clearly by reference to Fig. 3. The closure door 18 is hinged with door mount 25 on pin pivot 22. Closure mount 25 is soldered to end wall 5. The diameter of orifice 24 is determined by the size of pipettes utilized, as well as the width of the radial junction between the side walls. Of course, for a dispenser of various sized pipettes orifice 24 should be larger than the diameter of the largest pipettes used.

Fig. 4 is a view of front wall 3 showing plunger 11 and atfixed thereto rods 8 and 16. These rods pass through rod channels 16 and 10' in rod guide 10. Rod guide 10 is fastened to end wall 3 by means of screws 15 through flange 12 on this rod guide.

Fig. 5 illustrates the convergence of side walls 4 and 4. This convergence allows only one pipette at a time to be within the radial junction between the convergent side walls and between the internal end of rod 16 and orifice 24. In order to insure that pipette 23, when pushed by rod 16, will slide along in the said radial junction between the side walls 4 and 4 and through orifice 24, guide 26 is provided. This internal strip guide 26 prevents more than one pipette from falling into the radial junction and also prevents the pipette which is in the radial junction from rising out of it under pressure from rod 16.

Fig. 6 illustrates clearly the opening of closure 18 by rod 8. Pipette 23, which is shown starting to protrude from the dispenser through orifice 24, does not push against closure 18 in the opening of this closure.

Fig. 7 is a side cut-away view of the entire dispenser. The straight alignment along a substantially common horizontal axis of rod 16, pipette 23, and orifice 24 may be clearly seen.

In practice, the dispenser of the present invention has proven its actual utility in many bacteriological tests.

For example, the dispenser was filled with 5 ml. serological pipettes and sterilized in an autoclave with wet heat for one hour at 15 lbs. per square inch of steam pressure. The dispenser was allowed to cool and stand in an open laboratory room for four days. Ten pipettes were removed, at random times, from the dispenser during the four day period. After the four days another pipette was removed, swabbed thoroughly, the swab placed in media and incubated. No contamination was observed. This procedure was repeated during a period of two weeks for pipettes with sterility checks made on several pipettes and closure door 18. None of these sterility tests showed any trace of contamination.

Having thus described our invention, what we claim as new and wish to secure by Letters Patent is:

1. An apparatus for dispensing sterile pipettes while maintaining the same, as well as pipettes remaining in the apparatus, in sterile condition until dispensed, which comprises, in combination, a hopper for containing the pipettes, the hopper having a body defined by substantially equally and downwardly converging opposite side walls which are downwardly convergent to a radial junction having a curvature and width approximately corresponding to similar values of pipettes to be dispensed, whereby the pipettes sequentially drop into the juncture for sequential dispensation therefrom, the hopper having opposite ends closed by a pair of opposite closure end walls therefor, one of the end walls having a dispensing opening therein registering with the radial junction between the side walls through which opening the pipettes in the hopper may be sequentially ejected, a closure door for the opening hingedly mounted exteriorly on the end wall adjacent to the dispensing opening and being vertically hinged movable with respect to the end wall during its opening and closing movements, a counterweight on the door normally maintaining the door in closing position, the other of the pair of end walls being a plungermounting wall and having spaced openings therethrough for reception of a pair of spaced parallel plunger rods included in plunger means mounted on the outside of the said end wall and extending therethrough, the pair of plunger rods being of substantially unequal length, the longer rod being positioned outside the hopper at a level higher than said dispensing opening and having a length greater than that of the hopper when the plunger means are moved inwardly towards the plunger-mounting end wall, the longer rod bearing against the closure door for the dispensing opening in the opposite end wall for pushing the door open, the shorter plunger rod engaging a pipette in the radial junction between the side walls and partially ejecting the pipette through the opened door responsively to continued inward movement of the plunger relative to the plunger end wall, guide means for the plunger rods mounted exteriorly on the plunger end wall, a connecting yoke rigidly interconnecting the plunger rods for simultaneous parallel movement thereof, and a coil spring enclosing portions of a plunger rod compressed between the guide means and the yoke for normally urging the yoke and plunger rods to outward position with respect to the plunger end wall upon release of operating pressure on the plunger and removal of a partially ejected pipette through the open dispensing door, the counterweight for the door returning the door to closed position responsively to complete removal of the ejected pipette from the door, such removal enabling a following pipette to enter the juncture between the side walls of the hopper.

2. The dispensing apparatus of claim 1, wherein the convergent side walls of the hopper are surmounted by upright parallel upper portions, and a cover frictionally enclosing substantial upper portions of the side walls and of the end walls and defining therewith steam passages for escaping steam produced during sterilizing operations, while inhibiting ingress into the apparatus of contaminating air subsequent to such sterilizing operations.

References Cited in the file of this patent UNITED STATES PATENTS 67,317 Killin et a1 July 30, 1867 602,593 Axelson et a1. Apr. 19, 1898 846,314 Kabele Mar. 5, 1907 939,657 Beatty Nov. 9, 1909 6 Axelson et al. Apr. 5, 1932 Tilletson Oct. 24, 1933 Lloyd Feb. 6, 1934 ODonnell Mar. 16, 1937 Petrecca Dec. 8, 1953 FOREIGN PATENTS Sweden Mar. 7, 1908 Germany Feb. 25, 1939 Italy Oct. 1, 1935 Italy Mar. 29, 1949 Germany May 16, 1928

Images