US3214831A

US3214831A - Pipette de-stuffer

Info

Publication number: US3214831A
Application number: US322890A
Authority: US
Inventors: Vernell R Shellman; Carl J Veley
Original assignee: Upjohn Co
Current assignee: Pharmacia and Upjohn Co
Priority date: 1963-11-12
Filing date: 1963-11-12
Publication date: 1965-11-02
Anticipated expiration: 1982-11-02
Also published as: SE302696B; NL6413216A; CH426318A; GB1013487A

Description

NOV 2, 1965 v. R. sHELLMAN ETAL 3,214,331

PIPETTE DE-STUFFER Filed NOV. l2, 1963 5 Sheets-Sheet l INVENTORS VERA/ELL P. SHELLMAN |02/ m BYCAPL J mmf NOV 2, 1965 v. R. SHELLMAN ETAL 3,214,831

PIPETTE DE-STUFFER 3 Sheets-Shes?I 2 Filed Nov. 12, 1963 INVENTORS Vlg/@NELL Q. SHELL/MAN BY CAPI. J ff/ EV AUGE/VES] ya [532(a NOV- 2, 1965 v. R. SHELLMAN ETAL 3,214,831

PIPETTE DE-STUFFER 3 Sheets-Sheet 3 Filed Nov. l2, 1963 INVENTORS VEENELL ,9. SHELLMAN BYA/QL J m54/ United States Patent O 3,214,831 PIPETTE DE-STUFFER Vernell R. Shellman, Kalamazoo, and Carl J. Veley, Richland, Mich., assignors to The Upjohn Company, Kalamazoo, Mich., a corporation of Delaware Filed Nov. 12, 1963, Ser. No. 322,890 Claims. (Cl. 29-427) This invention relates in general to a machine for removing a removable obstruction from within an elongated tube and, more particularly, to a machine for removing the filter plug from within each mouthpiece end of a plurality of pipettes each having a restricted orifice at the other end thereof.

It is well known that large quantities of pipettes are used in certain fields, particularly by chemists, biologists, chemical engineers and their laboratory assistants, in conducting tests, in carrying out research and development projects and sometimes in production work. For example, large quantities of pipettes are used to conduct experiments during the development and testing of medicines and other pharmaceuticals. Obviously, the instruments used in conducting tests with medicines and similar products must be completely sanitary and often sterile. Thus, each pipette must be thoroughly cleaned after each use if it is to be reused.

Where large numbers of pipettes are used by a single entity or by a related group of entitles, such as a large research complex, it is not uncommon to have a separate but associated department for cleaning pipettes and other similar instruments which are used in all of the various research departments of the complex.

It is customary to stuff the mouthpiece end of each clean pipette with a filter material, such as a cotton plug, to protect the research worker who uses the pipette and to minimize contamination of the interior of the pipette. That is, the cotton filter placed in the mouthpiece end of the pipette minimizes the chance that the material in the pipette will be drawn into the mouth of the worker who is operating the pipette. Moreover, and at the same time, the cotton filter minimizes the chance of contaminating the chemical which is drawn into and expelled from the pipette by the research worker.

A machine for stuiiing a cotton filter plug into a pipette has been developed and is disclosed in patent application Serial No. 141,840, which is assigned to the assignee of this application. However, insofar as I am aware, no machine has been developed for the purpose of automatically removing the filter plug from each of the .pipettes after the pipettes have been used.

The removal of the cotton or other filter plugs from pipettes, after they have been used, has been troublesome and time-consuming. Previously, the filter plug has been removed either by an instrument, which is inserted into the pipette, or by directing a stream of uid under considerable pressure into one end of the pipette so that the plug is discharged thereby from the other end of the pipette. To the extent that this latter procedure is presently in use, it is conducted manually on a one-at-a-time basis. That is, each pipette must be manually engaged and placed in position with respect to the stream of pressure duid so that the discharge of the filter plug therefrom can be effected in a controlled manner. This procedure has become tedious, often messy, and also increasingly costly.

Accordingly, a primary object of this invention has been the provision of a machine for automatically removing from an elongated tube a removable obstruction therein.

A further object of this invention has been the provision of a machine, as aforesaid, for automatically and quickly removing a lter plug from the mouthpiece end 3,214,83l Patented Nov. 2;, 1955 ICC of a plurality of pipettes without creating a messy condition.

A further object of this invention is to provide greater safety for the operating personnel by enclosing the plug removing operation so that the personnel are protected from injury by a weakened pipette which may explode when the pressure liuid is applied to the pipette to remove the plug.

A further object of this invention has been the provision of a machine, as aforesaid, which is capable of handling at the same time a plurality of pipettes of various cross sectional dimensions, which is relatively small and compact in size, which can be operated easily by any person capable of removing the filter plugs from pipettes according to existing procedures for this purpose, and which is completely automatic in its operation after the pipettes have been placed therein.

A further object of this invention has been the provision of a machine, as aforesaid, which is relatively inexpensive to produce, which is extremely inexpensive to operate, which is assembled from components that can be quickly and easily separated from each other for the purpose of cleaning the machine, and which requires little or no maintenance.

Other objects and purposes of this invention will become apparent to persons familiar with this type of equipment upon reading the following descriptive material and examining the accompanying drawings, in which:

FIGURE 1 is a perspective view of a machine embodying the invention.

FIGURE 2 is a sectional view taken along the line II-II in FIGURE 1.

FIGURE 3 is a sectional view taken along the line III-III in FIGURE l.

FIGURE 4 is a broken, front elevational view of said machine.

FIGURE 5 is a sectional View taken along V-V in FIGURE 2.

FIGURE 6 is a sectional view taken along the line VI-VI in FIGURE 2.

FIGURE 7 is a sectional view taken along the line VII-VII in FIGURE 5.

FIGURE 8 is a fragment of FIGURE 7 showing a portion thereof in a different position of operation.

FIGURE 9 is an enlarged, broken fragment of FIG- URE 3.

FIGURE l() is a perspective View of the frame structure of the machine with the conveyor unit and the subframe removed.

FIGURE 11 is a perspective fragment of the conveyor unit showing the driven half of the coupling connected to the conveyor.

FIGURE l2 is a broken .perspective fragment of the frame structure of the machine disclosing the driving half of the coupling which is connected to the conveyor.

For the purpose of convenience in description, the terms npper, lower and words of similar import will have reference to the machine of the invention as appearing in FIGURES 1 and 2. The terms front, rear and words of similar import will have reference to the right and left sides, respectively, of the machine as appearing in FIG- URE 2. The terms inner, outer and derivatives thereof will have reference to the geometric center of said machine and parts thereof.

the line General description The objects and purposes of the invention, including those set forth above, have been met by providing a machine having a removable conveyor unit by which a plurality of pipettes, for example, having various diameters can be held in parallel spaced relationship and continuously advanced along a path toward a position at which the lter plug in each pipette is removed therefrom. A positioning mechansim within the machine receives the pipettes from said conveyor unit and moves them, one at a time, into and out of the discharge position.

Guide means directs a stream of uid under pressure into the machine so that the stream can enter the constricted end of a pipette in said discharge position, and thereby eject the filter plug from the mouthpiece end of said pipette. The flow of pressure tiuid through the guide means is controlled by a device responsive to the movement of the pipette into and out of the discharge position. Drive mechanism simultaneously operates the conveyor and the positioning mechanism in predetermined and cooperating relationship.

Detailed construction The machine (FIGURES 1 and 4), which illustrates a preferred embodiment of this invention, is comprised of a frame structure 11 which removably supports a conveyor unit 12 for receiving a plurality of elongated tubes, such as the pipettes 13, and for advancing them in uniform spaced relationship toward a discharge position 13a (FIGURE 5). The filter plugs F in the ends of pipettes 13 may be formed of cotton roving. A positioning mechanism 16, also mounted upon and within the frame structure 11, receives the pipettes 13, one at a time, from the conveyor unit 12 and moves them through said discharge position 13a. The frame structure 11 includes a compartment 17 (FIGURES 1 and 4).

The frame structure 10 (FIGURES 1 and 4), which is preferably substantially rectangular, includes a pair of

parallel side walls

21 and 22, which are connected near one edge of each to the opposite ends of the rear wall 23 by the screws 24 (FIGURE 6). A partition 26, which is preferably of about the same size and shape as the left side wall 22, is secured along one edge thereof to the rear wall 23 by means of the screws 27 so that said partition is near to, spaced from and parallel with said right side wall 22 to define therebetween a gear box 28.

The front edge portions of the partition 26 and the left side wall 21 are secured to opposite ends of a front wall 31 by the screws 32. Said front wall 31 extends from the lower edges of the left side wall 21 and partition 26 upwardly about half way toward the upper edges of said partition and side wall.

The gear box 28 has a top wall 33, front wall 34 and bottom wall 36 (FIGURE 3), which extend between the partition 26 and the right side wall 22. The rear wall of the gear box is provided by the rightward end of the rear wall 23 of the frame structure. The right side wall 22 is mounted upon the top wall 33, front wall 34 and bottom wall 36 of the gear box 28 so that the right side wall can be removed easily and quickly to examine the contents of the gear box 28. The front wall 31, the left side wall 21, the partition 26 and the portion of the rear wall 23 extending between the side wall 21 and the partition 26 define the pipette handling compartment 37, which is open at the upper and lower ends thereof, in this particular embodiment. The various parts of the frame structure 11 and conveyor 12, except the belt 58, are preferably fabricated from metal, such as stainless steel and/ or aluminum.

The conveyor unit 12 (FIGURES 1 and 2) is disposed within the upper portion of the handling compartment 37 so that said conveyor extends from adjacent the rear wall 23 over, and frontwardly of, the front wall 31. The frontward extension of said conveyor 12 can be varied to increase o1' decrease the pipette holding capacity of the conveyor. The conveyor 12 includes a pair of substantially parallel and

coextensive side plates

38 and 39 upon and between which the front roller 42 and rear roller 43 are rotatably supported in spaced parallel relationship. The front roller 42 has

stub shafts

44 and 44a, which are rotatably and adjustably supported in the

horizontal slots

46 and 47, respectively, in the front ends of the

side plates

38 and 39, respectively. The rear roller 43 has

stub shafts

48 and 48a which are rotatably supported in the

bearings

51 and 52, respectively, which are mounted in the rearward ends of the

side plates

38 and 39, respectively.

A pair of cylindrical adjustment blocks S3 and 54 (FIGURE 6) are held in the

slots

46 and 47, respectively, by the

screws

56 and 57 on the rearward side of, and for engagement with, the

stub shafts

44 and 44a. By appropriate rotation of the blocks 53 and 54, the roller 42 can be moved horizontally with respect to the roller 43, whereby the tension on the conveyor belt 58, which encircles said rollers, can be varied.

The rollers 42 and 43 (FIGURE 6) have a plurality of similar and radially aligned grooves 61 and 62, respectively, for receiving rows of guide elements 63 which are mounted along the inner surface of the belt 58 for positively preventing movement of the belt axially of said rollers during the movement of the belt around said rollers. A plurality of elongated spacing elements 64, such as stainless steel or plastic bars, are secured upon the outer surface of the belt 58 in spaced and parallel relationship. Bridge members 66 may be secured to the upper surface of the belt between selected ones of said spacing elements 64 to control the spacing and number of grooves 67 defined by said spacing elements 64 into which the pipettes 13 may be received. The width of each groove 67 is sufficient to accommodate pipettes of various sizes within a reasonable range. The belt 58 may be fabricated from a flexible and somewhat resilient sheet material, such as plastic or a resin impregnated cloth.

It will be seen that the rows of elements 63 could be replaced by spaced, parallel ridges, which are integral with the inner surface of, and project inwardly from the belt 58. Likewise, the spacing elements 64 and bridge members 66 could be integral, outward projections on said belt 58.

A pair of guide strips 65 and 65a (FIGURES 1 and 4) are mounted respectively upon the upper edges of the

side plates

38 and 39 for supporting and guiding the lateral edges of the upper reach of the belt 58.

Two pair of similar, coaxial support posts 68, 69 and 72, 73 (FIGURE 6) are mounted upon and substantially between the left side wall 21 and partition 26 for the purpose of removably supporting the conveyor unit 12. A pair of substantially coaxial support pins 74 and 75 are secured to and extend in opposite directions away from the

side plates

38 and 39, respectively, near to but spaced from the front ends thereof. The front support posts 68 and 69 are rigidly secured to the side wall 21 and the partition 26, respectively, by the screws 79. The adjacent ends of the front support posts 68 and 69 have

notches

77 and 78, respectively, which open inwardly, rearwardly and upwardly for reception and removable support of the support pins 74 and 75, respectively, to support the front end of the conveyor unit 12.

The adjacent ends of the rear support posts 72 and 73 have slots 82 and 83 (FIGURE 6) which open inwardly and frontwardly. The

bearings

51 and 52 project through and beyond the outer surfaces of the

side plates

38 and 39, respectively, for snug slidable reception into the

slots

82 and 83, respectively.

The support post 73 (FIGURE 1'2) has a central shaft opening 84 (FIGURE 6) which communicates between the slot 83 and the interior of the gear box 28. A shaft 86 is coaxially held within the shaft opening 84 by a bearing 87 so that the shaft 86 extends between the gear box 28 and the slot 83. A coupling 88 is secured to and connected between the inner end of the shaft 86 and thev outer end of the shaft 48a which extends into the slot 83 beyond the end of the bearing 52.

The coupling 88, which includes a driven part 89y (FIGURE 11) and driving part 92 (FIGURE 12) is; rotatably disposed within the slot 83 (FIGURE 6) when the conveyor unit 12 is in its operating position. The driven part 89 of said coupling has a wedge-Shaped prof jection 93 on its outer axial end, and the driving part 92 has a diametrically tapered slot 94 into which the projection 93 can be slidably and snugly received for effecting a sliding connection between the driven and driving parts.

A conveyor driving gear 96 (FIGURE 3) is supported upon the outer end of the shaft 86. A spring-backed ball 97 (FIGURE 9) is supported upon the gear 96 for reception into a recess 98 in the shaft 86 for the purpose of effecting a quick release connection between the gear 96 and the shaft 86. The conveyor driving gear 96 (FIG- URE 3) is engaged and driven through an idler gear 99 which is in turn engaged and driven by the drive gear 102, both of which are disposed within the gear box 28. The idler gear 99 is rotatably supported upon the partition 26, and the drive gear 102 is connected to one end of the drive shaft 103 which extends completely through the handling compartment 37 where it is connected at its other end to the drive motor 104, which is supported upon the side wall 21.

A pair of positioning gears 106 and 107 are rotatably supported within the gear box 28 approximately directly below the large idler gear 99 and the conveyor gear 96, respectively. The said positioning gear 106 is engaged and driven by the large idler gear 99. A small, reverse idler gear 10S is rotatably supported within the gear box 28 between the large idler 99 and the positioning gear 107 so that it is engaged with both gears. Thus, rotation of the idler gear 99 causes the positioning gears 106 and 107 to rotate in opposite rotational directions.

The gears 106 and 107 are mounted upon corresponding ends of the spaced and parallel positioning shafts 111 and 112 (FIGURES 2 and l0), which extend into and substantially through the handling compartment 37. The positioning shafts 111 and 112 are supported within the handling compartment 37 by

bearings

113 and 114 which are supported upon the front wall 31 and rear wall 23 by the bearing supports 116 and 117, respectively.

A pair of similar, resiliently flexible wheels 118 and 119 (FIGURES 5 and 10) are coaxially mounted upon the rear positioning shaft 112 on opposite sides of the bearing support 117. A pair of wheels 122 and 123 (FIGURES 4 and l0), which are preferably similar to the

wheels

118 and 119, are mounted upon and rotatable with the front positioning shaft 111 so that said

wheels

122 and 123 are adjacent to and radially aligned with the

wheels

118 and 119, respectively. In this particular embodiment, the

wheels

11S and 119 and 122 and 123 are fabricated from resiliently liexible sheet material, such as rubber or plastic, which is shaped to form a hollow, self-supporting annulus, like a tire. Each of the wheels is held in position upon its corresponding shaft by a pair of set collars 124 and 125, removably secured to said shaft on opposite sides of each wheel.

In this particular embodiment, all four of the

wheels

118, 119, 122 and 123, are substantially identical and are spaced downwardly from the lowermost point of the conveyor belt S a distance somewhat greater than the diameter of the largest pipette 13 which can be handled by the conveyor unit 12.

A pair of xed guides 127 and 12S (FIGURES 1 and 6) are mounted upon the rear wall 23 adjacent the upper edge thereof and adjacent the opposite lateral edgesl of the beit 58. Said guides 127 and 128 (FIGURE l0) have

semicircular recesses

129 and 130 in their frontward faces which are concentric with the axis of the rear roller 43 (FIGURE 2) and shaped from the outer surface of said belt 58 a distance slightly greater than the largest pipette 13 which the belt 58 is capable of handling. The lower extremities of the

recesses

129 and 130 are preferably disposed directly above and a slight distance from the upper portions of the

rear wheels

113 and 119. The gearing in the gear box 28 is arranged so that the

Wheels

118 and 119, as appearing in FIGURE 2 rotate in a clock- 6 wise direction, and the

wheels

122 and 123 rotate in a counterclockwise direction.

A guide plate 132 1(FIGURE 2), which is secured to the lower edges of the

guides

127 and 128, extends from the rear wall 23 to a line forwardly of the guides 127 and 12S. Said guide plate 132 has a downwardly extending flange 133 along its frontward edge to guide the movement of pipettes by the conveyor belt 58 from said plate 132 into the positioning mechanism 16. This arrangement tends to insure movement of the pipettes from the conveyor unit 12 into the nip of the

wheels

118, 119, 122 and 123 in a position, as shown in FIGURES 2 and 5, which is parallel with the axes of said wheels.

A splash plate 134 (FIGURE 2) is mounted at its frontward end upon the front ends of the side plates 3S and 39 from which it extends rearwardly beneath the conveyor belt 58, over the top of the front wall 31 and to a line above and close to the rearward sides of the

wheels

122 and 123.

The rearward edge of the Splash plate 134 is also anged downwardly.

A pair of stops 136 and 137 (FIGURE 1) are supported upon and forwardly of the guides `127 and 128 by means of the

resilient elements

138 and 139 to Obstruct the rearward movement of any pipettes which are not properly in a groove 67. A wedge 142 is mounted upon the partition 26 between the rear wall 23 and the rearward roller 43 so that its exposed surface 143 diverges downwardly with respect to the adjacent surface of the partition 26. The wedge 142 (FIGURE 4) is located so that the constricted end 144 of a pipette 13, which is too close to the partition 26, engages said surface 143 and moves such pipette a predetermined distance away from the partition 26, for reasons appearing hereinafter.

As shown in FIGURE 5, a nozzle 146 extends through the side wall 22, the gear box 28 and into the handling compartment 37 `so that it is substantially coaxial with a pipette 13 held in the discharge position 13a by the

wheels

118, 119, 122 and 123, which are part of the positioning mechanism 16. The nozzle 146 is mounted upon and held with respect to the frame structure 11 in a conventional manner. The discharge or inner end 148 of the nozzle 146 is spaced from the inner surface of the partition 26 a distance slightly less than the maximum thickness of the wedge 142 to prevent interference between the constricted ends 144 of the pipettes 13 and the inner end 148 kof the nozzle 146. The outer end of the nozzle 146 is connected by the coupling 147 to a pipe 149 which is connected to a substantially conventional solenoid valve 152, which is in turn connected to a source of pressure uid, not shown, such as compressed air.

A switch 153 (FIGURES 5 and 6) is mounted upon the partition 26 within the handling compartment 37 so that its actuator 154 extends downwardly adjacent the constricted end 144 of a pipette 13 being held by the positioning mechanism 16. Said switch actuator 154 is engaged by each pipette, as it is moved downwardly by said position mechanism 16, so that the switch 153 is closed by a pipette 13 disposed in the discharge position 13a (FIGURE 5). Closing of the switch 153 operates the solenoid valve 152 whereby pressure fluid is discharged through the nozzle 146 into the constricted end 144 of the pipette in the discharge position 13a. The pressure fluid drives the filter plug F out of the pipette through the mouthpiece end thereof. As soon as the pipette is moved out of the discharge position 13a, it becomes disengaged from the switch actuator 154, whereby the switch 153 is opened and the flow of pressure fluid through the nozzle 146 is terminated by the solenoid valve 152.

An exhaust pipe 156 is connected to and extends through the left side wall 21 (FIGURES 1 and 5) in a position substantially coaxial with the nozzle 146 and a Y feet per minute.

pipette in the discharge position 13a (FIGURE 5). The pipe 156 may be connected to a vacuum source, not shown, by means including the hose 157 (FIGURE 1). Thus, a plug F discharged by the pressure fluid from a pipette in the position 13a will ordinarily be directed into the pipe 156 and thereafter drawn away from the machine 10 by a pressure which is substantially less than ambient pressure.

A pair of guide disks 158 and 159 (FIGURES 6, 7 and 8) are mounted upon the positioning shafts 111 and 112, respectively, near the partition 26 so that they engage and guide the constricted end 144 of each pipette 13 accurately into the discharge position 13a (FIGURE The

guide disks

158 and 159 are preferably fabricated from a resiliently flexible material, such as rubber, which is somewhat stiffer than the material contained in the

wheels

118 and 119, for example. Thus, the peripheral surfaces of the

guide disks

158 and 159 which can be depressed by the pipettes 13 without breaking same, cause the ends 144 of said pipettes to move into and out of the desired position of alignment with the nozzle 146 as the pipettes 13 move through the discharge position 13a. Accordingly, the plug F will be discharged from each pipette, even though the pipette is moved through the `discharge position 13a without being precisely coaxial with the nozzle 146.

In this particular embodiment, the receptacle 18 is disposed in the lower compartment 17, which is defined by a substantially channel-shaped subframe 162 (FIG- URE l) having a bottom plate 163 and a pair of

side plates

164 and 165 which extend upwardly from said bottom plate and are secured to the

side walls

21 and 22, respectively, of the frame structure 11 by means of screws, such as those appearing at 167. The receptacle 18 extends completely under the handling compartment 37 so that it not only receives all of the pipettes 13 which have passed through the discharge position 13a, but also receives any moisture which drops from the pipettes as they are moved by the conveyor 12 and the positioning mechanism 16. The receptacle 18 can be slidably moved into and tout of its position (FIGURES 2 and 4) in the compartment 17.

Operation The machine is prepared for operation by placing ya receptacle 18 within the lower compartment 17, by

nected to the same source of electrical energy supplied to the drive motor 104. A plurality 'of pipettes 13 is now placed upon the upper reach of the belt 58 and preferably within the grooves 67. It is immaterial if one or more of the grooves 67 remain unfilled.

The belt 58 is moved by the gears in the gear box 28 at a relatively slow rate, such as about five to ten The pipettes are moved rearwardly by the belt 58, then downwardly along the recessed sur- :faces 129 and 130 of the

guides

127 and 128, respectively, and thence frontwardly along the guide plate 132 until they pass over the anged, front edge 133 of said plate 132. The

stops

136 and 137 obstruct the rearward movement of any pipette which is not properly within a groove 67. The wedge 142 will engage any pipette which is too close to the partition 26 and move it leftwardly, as appearing in FIGURE 4.

If a pipette should become jammed in the

guides

12 and 128, for example, or if the normal movement of the belt 58 should in any other way be obstructed, the

spring-backed ball 97 (FIGURE 9) will be urged out of the recess 98. Thus, the gear 96 can rotate within the gear box 28 without rotating the shaft 103 and, therefore, without damaging the conveyor unit 12 or a pipette 13.

Each pipette 13 is moved, one at a time, from the 8 guide plate 132 into the nip between the

wheels

118, 119, 122 and 123, which then move each pipette 13 downwardly through the discharge position 13a (FIG- URES 5 and 8) and into the receptacle 18.

As shown in FIGURES 7 and 8, the switch actuator 154 is ycaused by the pipette 13 to close the switch 153 just before the pipette 13 arrives into the discharge position 13a. Said pipette 13 becomes disengaged from the switch actuator 154, whereby the switch 153 is permitted to reopen shortly after the pipette moves away from the discharge position 13a. Y

As stated previously, closure of the switch 153 operates the solenoid valve 152 whereby pressure fluid is discharged at a high velocity through the nozzle 146 and into and through the pipette 13 in the discharge position 13a, whereby the filter plug F is discharged therefrom into the exhaust pipe 156.

The foregoing operation may be continued indefinitely, it being necessary only to supply pipettes to the conveyor unit 12 and occasionally empty them from the receptacle 18.

Although a particular preferred embodiment of the invention has been disclosed herein, it will be understood that variations or modifications of such disclosure, which come `within the scope of the appended claims, a-re `ful-ly contemplated.

What is claimed is:

1. A machine for removing a removable obstruction from within an open ended tube, comprising:

a frame structure;

conveyor means mounted upon said frame structure for moving said tube into and out of a position for discharging the obstruction therefrom;

pressure uid guide means mounted adjacent to said conveyor means and being located close to an end of a tube at said position, said guide means having a discharge opening which opens toward said position in a direction transverse to the direction of movement of the conveyor means, said discharge opening being aligned and substantially parallel with the lengthwise axis of a tube supported on said conveyor means at said position, and means connecting said guide means to a source of pressure fluid whereby a stream of pressure fluid can be directed lengthwise into and through a tube when it is in said position; and

control means responsive to movement of said tube into and out of said position for starting and stopping the ow of pressure fluid through said nozzle means. 2. A machine for removing a removable obstruction from within an open ended tube, comprising:

a frame structure; conveyor means mounted upon said frame structure for receiving said tube and moving same into and out of a position for discharging the obstruction therefrom, said conveyor means including movable positioning means for firmly engaging a tube at said position and temporarily holding said tube in said position; nozzle means mounted on said iframe structure adjacent to said conveyor means in alignment with said position and extending close to an end of a tube at said position, said nozzle means having a discharge opening which opens toward said position in a direction transverse t0 the direction of movement of the conveyor means and substantially parallel with the lengthwise axis of a tube supported thereon at said position, and means connecting said nozzle means to a source of pressure fluid whereby a stream of pressure fluid can be directed lengthwise into and through a tube when it is in said position; and

control means responsive to movement of said tube into and out of said position for starting and stopping the flow of pressure fluid through said guide means.

3. A machine for removing a removable filter plug from within a pipette having a constriction at one end thereof, the combination comprising:

a frame structure;

plurality of spaced and parallel grooves extending transversely of the direction of said movement for receiving said pipettes therein;

positioning means supported within and upon said conveyor means mounted upon said frame structure for 5 frame structure beneath said lower reach for rereceiving a plurality of pipettes and moving same in ceiving said pipettes from said conveyor and moving a direction transverse to the lengthwise axis thereof Said pipettes one at a time in uniform intervals into toward a position for discharging the plug therefrom; and out of a position substantially perpendicular to movable positioning means for receiving said pipettes Said side walls for discharging the iltel meaIiS from said conveyor means and moving said pipettes m through the mouthpiece end thereof; in a direction transverse to the lengthwise axis therenOZZle means mOllntcd in the Side Wall adjacent the of one at a time into and out of said position, said constricted ends f Said pipettes and connectible to positioning means including means for holding said Said Souffle 0f PreSSnie fluid fOr directing Said prespipettes against movement while they are in said Sure llid iIlO the CQnStriCtcd end Of a pipette in position; said position, whereby the filter plug is ejected by the nozzle means mounted on said frame structure ad- PleSSUYe ilniti from tile PiPette through the monthjacent to said positioning means in alignment with Piece end thereof; said position and extending dose to an end of a control means operable by each pipette as it moves into pipette at said position, said nozzle means having said position for initiating the flow of pressure uid a discharge opening which opens toward said position thlilgh Said 1102216 means, and operable by said in a direction transverse to the direction of movepipette aS Said pipette iS moved 011 0f Said position ment of the positioning means and substantially and fnl' terminating the iiOW Of Pi'esiife fluid through parallel with the lengthwise axis of a pipette sup- Said DOZZle means; and ported thereon at said position, and means connectdrive means mounted upon said frame structure and ing said nozzle means to a source of pressure fluid Connected t0 Said Conveyor and Said Positioning whereby a stream of pressure fluid can be directed lengthwise into and through a pipette when it is in means for actuating same. 6. A method for removing filter plugs from within the mouthpiece end of a plurality of pipettes each having a constriction at the other end thereof, the steps comprising:

placing a plurality of the pipettes in parallel, uniformly said position. 4. A machine for removing a removable filter plug from within a pipette having a constriction at one end thereof, the combination comprising:

a frame structure; conveyor means mounted upon said frame structure for receiving a plurality of pipettes and moving same in a spaced positions defining a substantially horizontal plane with the constricted ends thereof extending in the same direction;

direction transverse to the lengthwise axis thereof tomoving the constricted ends of said pipettes into lateral ward a position for discharging the plug therefrom; alignment .Witii enen other;

a pair of movable positioning means disposed adjacent advancing .Said pipettes at a Uniform Speed along a Patil to and facing each other for receiving and gripping substantlally perpendicular to said pipettes toward therebetween pipettes from said conveyor means and a dieeliaige POSltlOIl; moving said pipettes in a direction transverse to the moving Said pipettes One at a time and at uniform inlengthwise axis thereof one at a time into and out of tefiia'ls away from Said Patil and iIltO Said discharge said position, said positioning means holding said Position pipettes against movement with respect to Said posi directing a stream of pressure fluid into the constricted tioning means while they are in said position; end if eacii PiPet te and lengthwise thereof While nozzle means mounted on said frame structure adfhePiPette is in Said POSitiOn, S0 that the iiltcr plug jacent to said positioning means in alignment with is elected therefrom; and

said position and extending close to an end of a pipette at said position, said nozzle means having a discharge end opening which opens toward said position in a direction transverse to the direction of an endless conveyor having substantially horizontal upper and lower reaches mounted upon and between said side walls for movement lengthwise thereof, said conveyor having a plurality of elements projecting from the outer surface thereof and defining a moving each said pipette out of said position and into a collecting zone. 7, A machine for removing a removable filter plug from within a pipette, comprising:

mvement of the positioning means and Substantially a pair of rotatable, substantially parallel and horizontal parallel with the lengthwise axis of a pipette sup- Shafts; ported thereon at said position, and means com wheel means mounted on each of said shafts for rotation necting said nozzle means to a source of pressure threwlthxthe Whfiel meais un the respective Shafts fluid whereby a stream of pressure fiuid can be directr, lemg radially aligne@ with each other and posi ed engthwise into and through a pipette when it is o0 tioned so that the peripheralsurfaces of said wheel in Said position; and means are movable substantially into contact with control means responsive to movement of each pipette each other at a z One bqtiveen Said Shafti said periph by said positioning means into said position for inieral Surfaces bemg reslhent Wherebyplpettes can be tiating the fiow of pressure fluid through said nozzle placed m. the gap between Said peripheral surfaces means, said control means being responsive to moveabove Sald Zone and then can be .engaged thereby ment of each pipette out of said position for termiand moved downwardly through. sind Zone and then natiug the fiow of pressure fiuid through said nozzle imp downwardly away from Sald Wheel means; and meansuld supply means mounted adjacent corresponding 5. A machine for removing removable filter plugs Sme ends. of said Shafts. Said iuid Sulipy mea. hav" from within the mouthpiece end of a plurality of pipettes ling. a dis-charge openmg axially ahgned with. and having constricted orifices at their other ends, comprisacmg Said Zonefor Supplymg a Pressure md .to ing: oie end of a pipette located 1n said zone for d1s a substantially rectangular frame structure having a 8 pAacmg lill-1e lter pllg therefrom' pair of spaced and parallel Side Wans' mac me accor ing to claim 7, mcludmg conveyor means d1sposed above said shafts for supplying pipettes one at a time to said gap.

9. A machine for removing a removable filter plug from within a pipette, comprising:

a frame structure; conveyor means mounted upon said frame struct-ure,

said conveyor including means for supporting individual pipettes at spaced-apart points therealong for moving same ina direction transverse to the lengthwise axis thereof;

pair of endless movable positioning elements disposed directly below said conveyor means, said positioning elements being disposed adjacent to each other and having downwardly movable surface portions vpositioning elements, said positioning elements then extending away from each other below said zone, then upwardly and thence back toward said gap;

nozzle means mounted on said frame structure adjacent one horizontal end of saidzone, said nozzle means having a discharge opening extending between and transverse to the direction of movement of said positioning elements and substantially parallel with the lengthwise axis of a pipette disposed in said zone,

and means connecting said nozzle means to a source of pressure fluid whereby the pressure fluid can be directed lengthwise into and through a pipette when it is in said zone.

10. A machine according to claim 9, in which said conveyor means is an endless, substantially horizontally disposed, pulley-supportedvbelt conveyor having upper and lower reaches and having upstanding elements thereon for engaging the pipettes and moving them with said conveyor, the lower reach of said conveyor extending across the upper end of said gap and arcuate wall means extending part way around one of the pulleys and thence lsubstantially to said gap whereby the pipettes move along said wall means and are deposited into said gap.

References Cited by the Examiner UNITED i STATES PATENTS 3/27 Murray 25.-128 X 7/52 Broden 18-:2

Claims

6. A METHOD FOR REMOVING FILTER PLUGS FROM WITHIN THE MOUTHPIECE END OF A PLURALITY OF PIPETTES EACH HAVING A CONSTRICTION AT THE OTHER END THEREOF, THE STEPS COMPRISING: PLACING A PLURALITY OF THE PIPETTES IN PARALLEL, UNIFORMLY SPACED POSITIONS DEFINING A SUBSTANTIALLY HORIZONTAL PLANE WITH THE CONSTRICTED ENDS THEREOF EXTENDING IN THE SAME DIRECTION; MOVING THE CONSTRICTED ENDS OF SAID PIPETTES INTO LATERAL ALIGNMENT WITH EACH OTHER; ADVANCING SAID PIPETTES AT A UNIFORM SPEED ALONG A PATH SUBSTANTIALLY PERPENDICULAR TO SAID PIPETTES TOWARD A DISCHARGE POSITION; MOVING SAID PIPETTES ONE AT A TIME AND AT UNIFORM INTERVALS AWAY FROM SAID PATH AND INTO SAID DISCHARGE POSITION; DIRECTING A STREAM OF PRESSURE FLUID INTO THE CONSTRICTED END OF EACH PIPETTE AND LENGTHWISE THEREOF WHILE THE PIPETTE IS IN SAID POSITION, SO THAT THE FILTER PLUG IS EJECTED THEREFROM; AND MOVING EACH SAID PIPETTE OUT OF SAID POSITION AND INTO A COLLECTING ZONE.