US 2722257 A
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Description (OCR text may contain errors)
'1955 M. LOCKHART SAMPLING TUBE EQUIPMENT Filed Feb. 12, 1953 INVENTOB 5/7422 1. 40417421 United States Patent SAMPLING TUBE EQUIPMENT Marshall L. Lockhart, Rutherford, N. J., assignor to The Compule Corporation, Rutherford, N. J a corporation of New Jersey Application February 12, 1953, Serial No. 336,467
8 Claims. (Cl. 15(l--.5)
which to spin or whirl around containers or vials loaded with liquid specimens or blood samples to subject the latter to centrifugal forces. Such devices usually consist of a rotor adapted to be spun around in a horizontal plane and equipped with a series of elongated cups pivotally mounted near their open mouths so as to depend vertically when the rotor is still, their bottoms being adapted to swing out and up to dispose the cups substantially radially when the rotor is rotated. Thus the cups are easily loaded with Sampling tubes by dropping the latter therein while the cups rest in depending positions and are readily unloaded either by lifting the tubes therefrom or by inverting the cups to spill out the contained tubes if the latter are closed to avoid spillage of contents. Some such centrifuges are equipped with cups having fiat transverse bottoms while others carry cups having tapered or conical bottoms, the latter at times being converted to fiat-bottomed cups by dropping into their tapered bottoms conical plugs having flat tops. However, such conical plugs have a tendency to wedge securely into the tapered ottoms of the cups making their removal difiicult when conversion to employable tapered bottoms is desired.
Anobject of the present invention is to provide certain sampling tube closures which effectively avoid such difiiculties and efficiently adapt elongated closed sampling tubes having elongated inlet and outlet hollow necks to mountation and subjection to centrifugal force in centrifuges equipped with either type of cups.
Another'object of the present invention is to provide r such sampling tube closures in forms which are easily and economically manufactured on a mass production basis, each of which can be quickly applied as a secure closure to such a sampling tube, and which will seat in readily removable fashion in either flat or tapered bottoms of such centrifuge cups, and which eliminate necessity for use of conical plugs.
A further object of the present invention is to provide in'combination such sampling tubes and closures therefor which simplify subjecting liquid specimens or blood samples to centrifugal action.
A' still further object of the present invention is to provide structural embodiments which are readily made and permit eificient use.
Other objects of the invention will in part be obvious and 'will in part appear hereinafter.
The invention accordingly comprises the features of construction, combination of elements and arrangement of parts, which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.
For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawing, in which:
Fig. 1 is an exploded perspective view of a blood sampling suction device or syringe of the type claimed in my copending application Serial No. 309,421, illustrating the ampule or tubular container thereof which may constitute the tube element of the combination of the present invention;
Fig. 2 is an elevational view, with parts broken away and in section, of the suction syringe of Fig. 1, illustrating its use in taking a blood sample from a'vein;
Fig. 3 is an enlarged perspective view of an embodiment of the closure of the present invention;
Fig. 4 is an elevational view of the tube of Figs. 1 and 2 and the closure of Fig. 3, showing the latter mounted on the former in closing position;
Fig. 5 is an enlarged detailed view with parts broken away and in section, of the upper portion of the tube shown in Fig. 4 and the closure mounted thereon;
Fig. 6 is a top plan view, diagrammatically showing the essential elements of the rotor of a typical centrifuge, in rest or still position;
Fig. 7 is a side elevational view of the centrifuge structure illustrated in Fig. 6, and depiciting the mounting'of a plurality of the closed tubes of Figs. 4 and 5 in the centrifuge cups;
Fig. 8 is an axial section, with parts broken away, to enlarged scale of the bottom portion of one of the taperedbottom centrifuge cups shown in Fig. 7, and illustrating in elevation themounting therein of the inverted top portion of the tube and its closure of the present invention illustrated in Fig. 5;
Fig. 9 is a view similar to Fig. 8, illustrating the mount ing of the inverted tube and its closure in a flat-bottom centrifuge cup;
Fig. 10 is an axial section closure illustrated in Fig. 3;
Fig. 11 is an elevational view of a further embodiment of the closure of the present invention; and t Fig. 12 is a sectional view taken substantially on line 12-12 of Fig. 11.
Referring to the drawing in which like numerals identify similar parts throughout, it will be seen that in Figs. 1 and 2 is illustrated a suction syringe of the type disclosed in my copending application Serial No. 309,421, which is particularly. adapted to the taking of blood samples. As therein indicated, the ampule or container 11 of the device may be in the form of an elongated tube of the collapsible tube type which may be molded from suitable elastic material, such as an elastic plastic, e. g., polyethylene, and the like. The tube 11 preferably is in the form of an elongated section 12-of substantially cylindrical tubular stock having elastic side walls closed at one end 13 by pinching and sealing the opposite sides together. The tube 12 is closed at the other end by head means 14 comprising an integral circular cross wall preferably molded integral with the side walls and carrying substantially axially thereof a projecting elongated tubular neck 15 having a bore 16 communicated with the internal chamber 17, as illustrated in Fig. 5.
In order to employ the tube 11 of Fig. 1 for the purpose of taking a sample of blood, the operator may mount a needle assembly 18 thereto, by telescoping its hollow hub 19 over the neck 15, and then collapse the tube section 12 to expel the major portion of the air therefrom, as is more fully explained in my identified copending application. Thereafter, he may thrust the sharp piercing end 20 of the needle 12 into a patients flesh, diagrammatically illustrated at 22 in Fig. 2, to
of a modified form of the communicate its bore with a vein 23 therein, and then take a blood sample by releasing the side walls of tube section 12 so that it will spring back or out to its full line position as illustrated in Figs. 1 and 2, so as to create suction in the chamber 17 to draw a quantity or sample of blood 24 thereinto, all as more fully explained in that copending application. Thereafter, the needle assembly 18 is removed from the tube neck 15 and the sampling tube 11 is closed by the closure of the present invention, such as by the embodiment 25 illustrated in Fig. 3.
As illustrated in Fig. 3 an embodiment of the closure of the present invention may comprise a unitary structure 25 preferably formed or molded from elastic material, such as elastic plastic, e. g., polyethylene and the like. In the form illustrated in Fig. 3, the closure 25 includes a substantially cylindrical body section 26 carrying on one end a truncated outwardly-tapered tip or frusto-conical section 27 terminating in a substantially fiat end bearing surface 28 of appreciable area and arranged substantially normal to the axis of the body 26 and the frusto-conical section 27. An elongated tubular neck 29 extends substantially axially from the other end of the body 26 having an outer end edge 30 circumambient of its bore 31. Within the neck bore 31 is provided an elongated plugging element 32 which is coaxially disposed therein to provide between it and the wall of the bore 31 an annular or circular space or slot 131, as will be seen from Figs. 3 and 5, the outer end 33 of the elongated plugging element 32 extends appreciably short of the tip edge 30 of the neck 29 so as to provide a tube neck receptive socket in the outer end of the closure neck 29, as shown.
As illustrated in Figs. 4 and 5, the closure 25 is fitted to the tube neck 15 securely to close the same. While broadly the closure 25 may be provided with a single tube neck-closing element, such as the plugging element 32 to telescope within the tube neck bore 16, or the hollow neck 29 to telescope over the tube neck 15, it is preferred to use both the plugging element and the closure neck cooperatively to assure a fluid-tight seal. Although the plugging element 32 may be outwardly tapered to be wedged into the tube neck bore 16, it is preferably substantially cylindrical and of circular crosssection at least in its root section with its outer end 33 of a lateral dimension or an external diameter slightly larger than the internal diameter of the outer end of the tube neck bore 16, so that when it is forced into the later its root section slightly expands the elastic tube neck 15 to assure obtainment of a secure fluid-tight seal. Further, although the internal diameter of the closure neck bore 31 at the neck tip 30 may be substantially the same as, or even slightly less than, the external diameter of the outer end of the tube neck 15, while allowing relative telescoping thereof due to the elasticity of these necks, the internal diameter of the closure neck bore at the neck tip 30 preferably is somewhat larger than the external diameter of the outer end of the tube neck so that the latter may be readily received within the socket provided by the outer end of the closure neck bore beyond the end 33 of the plugging or core element 32. A tight fit between the exterior of the tube neck 15 and the wall of the closure neck bore 31 may be assured even if the diameter of the oversized closure neck bore 31 be substantially uniform from end to end since the tube neck may be expanded by insertion of the core element 32 into the tube neck bore 16, as previously indicated. However, molding procedure is facilitated if the tube neck 15 is slightly tapered outwardly, and, for similar reasons, it may be desirable to have the closure neck bore 31 taper inwardly so that the circular space 131 is narrower at its bottom or inner end adjacent the closure body 26 than it is at the end 33 of the plugging or core element 32. This gradual narrowing of that circular space 131 into which the tube neck 15 is to be received will cause the latter to be tightly jammed therein for enhancement of the fluidtight seal attained between the plugging element 32 and the tube neck bore 16 when the closure neck 29 is telescoped inwardly over the tube neck.
The closure 25 has a dual function. This includes, in addition to the secure closure of the sampling tube 11, a seating and sampling tube supporting action in a support, e. g. the bottom of a centrifuge cup, which will be best understood from Figs. 6, 7, 8 and 9. As illustrated in Figs. 6 and 7, a typical centrifuge may comprise a rotor 34 mounted upon a rotatable shaft 35 which may be driven by any suitable means, such as an electric motor 36 supported by a stand or base 37, so as to dispose this rotor in a substantially horizontal plane as seen in Fig. 7. The rotor 34 includes a plurality of bifurcated radial arms 3838, each comprising a pair of laterally-extending substantially parallel members 39, 39 between which is pivotally supported an elongated open-top cup 40. The pivotal support of each cup 40 may be attained by a pair of diametrically-opposed, laterally-extending pins 41, 41 mounted on the sides of the cup above the center of gravity thereof, and, as illustrated in Fig. 7, preferably near the top 42 thereof, so that when the rotor 34 is not rotated the cups 4040 depend in substantially vertical positions, as there indicated. As is well understood in the art, when the rotor 34 is whirled or spun by its motive power, such as motor 36, the bottoms 43-43 of the cups 40-40 swing outwardly and up in the direction of the dot-dash arrows in Fig. 7 to substantially radial positions of the cups indicated in dotted lines at 44.
As illustrated in Figs. 7 and 8, the bottom 43 of each cup 40 may be tapered or of conical shape, as is characteristic of the cups of one common type of centrifuge. The inner wall 45 of the tapered cup bottom 43 is disposed at a certain acute angle to the axis of the cup, as is best seen in Fig. 8. Preferably, in accordance with the present invention, the conical surface of the frustoconical section 27 of the closure 25 is disposed at an acute angle to which the conical inner surface 45 of the cup bottom 43 is disposed, so as to assure substantially line contact at 46 between the outer edge of the flat end 28 of the closure and the inner bottom as to make removal of the closure diflicult, or for the closure to stick in the bottom of the cup when the tube 11 is lifted there from with consequent opening of the tube neck bore 16 and spilling of the tube contents. However, the tapered section 27 of the closure 25 assures a proper seating and coaxial centering of the tube assembly in the support provided by the tapered cup bottom 43, and this closure serves all the purposes of the prior art tapered cup plug while eliminating any necessity for use of the latter. The substantially flat end bearing surface 28 of appreciable area arranged substantially normal to the axis of the plug 25 provides a secure end seating surface on a relatively flat support surface, such as a fiat cup bottom as illustrated in Fig. 9. Thus truncating the conical tip 27 of the closure plug performs two functions, i. e., (l) assuring line contact of the tapered tip within a conical support or cup bottom (when the angles of taper differ) to make certain the closure plug will not stick in the support, and (2) provides the flat tip end for resting upon a fiat support surface.
As indicated in Fig. 10, the closure for the sampling tube 11 need not include a cylindrical section of substantial length, such as 26 of closure 25 shown in Figs. 3, 4 and 5. For example, the closure as referenced in Fig. 10 may comprise a frusto-conical body 127 having a substantially circular, transversely-extending tip end 128 of appreciable area and carrying on the opposite end thereof the elongated tubular neck 29. The plugging or core element of the embodiment of Fig. 10 may be in the form of an elongated hollow sleeve 133 co-axially arranged within the closure neck 29 and having its outer end 133 extending beyond the outer edge 30 of the closure neck. The elongated sleeve 132, which is to serve as a tube neck bore plugging element, may have its bore tapered inwardly as shown to facilitate removal of the mold core and that plugging element preferably is externally tapered outwardly to its outer end 133;so as readily to wedge into the tube neck bore. Thus, the circular space 231 between the plugging element 132 and the closure neck bore 16 is wider at its mouth than at the bottom thereof so that the tube neck will be wedgingly jammed therein when the closure neck 29 is telescoped over the tube neck.
The embodiment of the closure illustrated in Figs. 11 and 12 has been found to be particularly practical from a mass production point of view and readily marketable while satisfying the requirements dictating the development of the general characteristics of the closure of the present invention. As shown in Figs. 11 and 12, the main body of the closure 225 may be of cruciform shape comprising a plurality, preferably four in number, of longitudinally-extending, substantially radial ribs 45-45 of progressively decreasing depth toward the end bearing surface 228, and at least the outward portions thereof so that their edges are generally disposed substantially along the surface of an outwardly tapered cone. The closure 225 of Figs. 11 and 12 may be best understood by considering it to be producible from the closure 25 of Fig. 3 with axially-extending notches being formed in the sides of the cylindrical section 26 and the frustoconical section 27 so as to leave a relatively thin circular base plate 236 from which the closure neck 29 co-axially extends and with the bottoms of the notches disposed substantially on the surface of an axially-extending cylindrical plane which may be projected axially from the circular edge of the end surface 228. Thus, all of the operative characteristics of the various features of the closure of Figs. 3, 4 and 5 are embodied in the closure of Figs. 11 and 12 while realizing an important economy and saving of material from which the closures are molded.
It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efliciently attained and, since certain changes may be made in the above construction and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.
It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statement of the scope of the invention which, as a matter of language, might be said to fall therebetween.
Having described my invention, what I claim as new and desire to secure by Letters Patent is:
1. A combined centrifuge cup plug and closure for a sampling tube having a tubular inlet and outlet neck of certain internal and external diameters comprising, in combination, a body having one end in the form of an outwardly tapered tip to seat coaxially in a conical support and provided with a substantially fiat end bearing surface of appreciable area arranged substantially normal to its axis to seat on a flat support alternative to coaxial seating of the tapered tip in a conical support, and a tubular neck extending substantially axially from the opposite end thereof to be telescoped with the hollow inlet and outlet neck of such sampling tube to close said tube neck.
2. The combined plug and closure as defined in claim 1 characterized by said closure neck being of elastic material, of an internal diameter slightly less than the external diameter of such tube neck soas to be stretch ably receptive of the latter to forma fluid-tight seal, and
elongated to lap appreciably over such tube neck when the latter is of appreciable length. 1
3. The combined plug and closure as defined in claim 1 characterized by said outwardly tapered tip being frusto-conical in shape having a substantially unbroken conical surface.
4. The combined plug and closure as defined in claim 1 characterized by said outwardly tapered tip as comprising longitudinally extending, substantially radial ribs of progressively decreasing depth toward the end bearing surface whereby their edges are'generally disposed substantially along the surface of an outwardly tapered cone.
5. A combined centrifuge cup plug and closure for a sampling tube having an elongated tubular inlet and outlet neck of certain internal and external diameters comprising a unitary structure of elastic material including, in combination, a body having one end in the form of an outwardly tapered truncated tip provided with a substantially flat end bearing surface of appreciable area arranged substantially normal to its axis, an elongated tubular neck extending substantially axially from the opposite end of said body to be telescoped over the tubular inlet and outlet neck of the sampling tube to close the bore of said tube neck with appreciable lap thereof, and
a core element co-axially arranged in said tubular neck receivable in said tube neck bore to plug the latter.
6. A combined centrifuge cup plug and sampling tube closure comprising in combination; a substantially circular body of elastic material having one end in the form of an integral, outwardly tapered, cruciform shaped section terminating in a flat end bearing surface of appreciable area substantially normal to the axis of said body; an integral, elongated, tubular neck extending substantially axially from the other end of said body; and an integral, elongated, solid, substantially cylindrical, plugging element disposed within said neck and spaced from the inner wall of the latter to define a circular space receptive of a tube neck, said plugging element being of appreciably less length than said closure neck to define a tube neck-receptive socket in the outer end of the latter.
7. Centrifuge sampling equipment comprising, in combination; an elongated, collapsible sampling tube of elastic material closed at one end and having a hollow, outwardly-tapered, elongated, .integral neck extending from the other end with its bore providing an inlet and outlet passage for said tube, the outer end of said neck being of certain smaller diameter; and a closure for said tube comprising a substantially circular portion of elastic material having one end in the form of an integral, outwardly tapered, cruciform shaped section terminating in a flat transverse end of appreciable area to constitute a bearing surface for abutting the flat transverse bottom of a fiat-bottomed centrifuge cup; said closure having an integral, elongated, tubular neck extending substantially axially from the other end of said body and of an internal diameter at its outer end appreciably greater than the external diameter of the outer end of said tube neck but less than the external diameter of said neck in the vicinity of its base, whereby said closure neck readily receives the outer end of said tube neck but becomes tightly stretched about the base portion of said tube neck when they are forcibly telescoped together; said closure also having an integral, elongated, solid, rodlike plugging element substantially circular in crosssection at its root disposed within said closure neck and spaced from the inner wall of the latter to define a circular space receptive of said tube neck, said plugging element being tightly receivable in said tube neck bore and of a length appreciably less than the length of said surrounding closure neck to define a tube neck-receptive socket in the outer end of the latter.
8. The centrifuge sampling equipment as defined in claim 7 characterized by said cruciform shaped tip being 7 8 in the form of longitudinally extending, radially disposed References Cited in the file of this patent ribs having outward portions of their outer edges tapered UNITED STATES PATENTS outwardly whereby the outward portions of the edges f id ribs adjacent the end bearing surface are gen- Brown '7' June 1867 erally disposed substantially along the surface of an outggz gg "7 35: 2 d1 war y tapered cone, said I'lbS having additional outer 1,706,249 Naum Mar. 19' 1929 edge portions intervening said tapered edge portions and said circular portion which extend substantially from the circumference of the latter substantially parallel to the axis of said closure. 10