US 3802844 A
Description (OCR text may contain errors)
United States Patent Sendra et al. Apr. 9, 1974 FOLDABLE TEST TUBE RACK 3,655,110 4/1972 Eisenbach 229/25  Inventors: Jose F. Sendra; Joaquim Fernandes,
both of Miami, Fla. Primary E.\aminerMorris O. Wolk Assistant Examiner-Arnold Turk  Asslgnee' American. Hospital Supply Attorney, Agent, or FirmDaws0n, Tilton, Fallon &
Corporation, Evanston, 111. L
ungmus  Filed: Mar. 21, 1973 ] App]. No.: 343,541 ABSTRACT 52 us. (:1 23/259, 23/292, 211/74, A foldable test tube rack formed in one piece from a 21 1/85 single sheet of plastic material. The rack is formed and 51 1m. (:1 B0ll 9/06 pp in flattened condition, thereby Occupying  Field of Search 23/259, 292; 211/85, 74, minimal space for Shipment and storage, and is easily 211/73, 60; 264/295; 206/65 A, 17; 229/25; folded into an erected condition at the time use is re- 248/450 460 quired. Because of its simplicity of structure and economy of material, the rack is inexpensive to manufac-  References Ci d ture and may be discarded following use.
1 UN TED STATES PATENTS 5 Claims, 8 Drawing Figures 1,836,138 12/1931 Turner et a1 2ll/74 PATENTEDAPR 9 I974 Q SHEET 2 [1F 2 FOLDABLE TEST TUBE RACK BACKGROUND As is well known, test tube racks are commonly used in clinical laboratories and elsewhere, wherever it is necessary to support conventional test tubes during reaction or during (or awaiting) observation. Such racks are normally of the non-disposable type; that is, they are intended for relatively long term use in the laboratory. In special cases, however, it is desirable to provide a disposable rack designed only for relatively limited use. Thus, if special tubes are to be used in the test, or if contamination presents a special problem, or if the particular clinical test presents certain requirements for the rack (as where color comparisons are to be made, or where the degree of transparency of the tubes contents is a determinative factor), it may be desirable to provide an inexpensive disposable rack specifically designed for use with a given test, and to supply such a rack along with the reagents for performing that test.
SUMMARY This invention is concerned with an inexpensive plastic rack for supporting a plurality of test tubes. Unlike prior racks which have either been relatively bulky and awkward to storeand ship or which have been marketed in multiple-piece disassembled condition for later assembly by the user, the rack of this invention is formed of a single piece of plastic material which may be easily and quickly folded along a single fold line into an erected condition for immediate use. In its flattened condition, the rack may be convenientlypackaged for shipment in a compact package which includes the tubes and reagents necessary for use in the test. Later, when the rack is folded into erected condition by the user, mating portions of the hinged sections are automatically brought into alignment and lock or hold the rack in its operative condition. Because the entire rack may be inexpensively vacuum formed from a single sheet of plastic material, it may be made available at nominal cost and may be discarded after it has served the specific purpose intended.
Other advantages and objects of the invention will become apparent as the specification proceeds.
DRAWINGS FIG. 1 is a perspective view of a foldable test tube rack embodying the invention, the rack being illustrated in erected condition;
FIG. 2 is a top plan view of the rack;
FIG. 3 is a front elevational view of the rack;
FIG. 4 is a top plan view showing the rack in flat or unfolded condition;
FIG. 5 is an end elevational view showing the rack in unfolded condition;
FIG. 6 is an enlarged end elevational view illustrating the rack in erected condition and showing (in phantom) a test tube supported by the rack;
FIG. 7 is a still further enlarged sectional view taken along line 7-7 of FIG. 6;
FIG. 8 is a further enlarged fragmentary sectional view taken along line 8-8 of FIG. 6.
DESCRIPTION Referring to the drawings, the numeral 10 generally designates a test tube rack having a base section 11 and a back section 12. When the rack is in the assembled condition shown in FIG. 1, the base section is intended to rest upon any suitable support surface, such as a laboratory table or. counter. It will be observed that the base section has a rearwardly and upwardly sloping front wall 11a, a downwardly and rearwardly sloping top wall 11b, and side or end walls 11c. The lower edges of the front and side walls terminate in an outwardly-projecting flange 13 which extends along a single plane and which therefore is suitable for supporting the base section upon a flat table surface. Additionally, the flange performs the function of resisting flexure of the front and side walls and therefore rigidifies the entire base section, a particularly important function in view of the fact that the base section is of hollow construction and is open at its bottom.
When the rack is in erected condition, the back section 12 slopes generally upwardly and forwardly (FIGS. 1 and 6), projecting forwardly over a substantial portion of the top wall 11b of the base section. As so viewed, the back section provides a front wall 12a, a
top wall 12b, and end or side walls 120. The back section also provides a bottom wall 12d which is in juxtaposition with the rear portion of top'wall 11b of base section 11 when the rack is erected. A flange 14 extends along the rear edges of top and side walls 12b and and, like flange 13, serves to rigidify the entire section with which it is integrally formed. The upstanding back section is hollow, being completely open at its rear or back side.
A plurality of wells or depressions 15 are formed in the top wall 11b of the base section and, in the illustration given, are arranged in a uniformly-spaced series across the front portion of that wall. Each well is spaced the same distance in front of wall 12a of the upstanding back section 12. Section 12 is similarly provided along its front and top'walls with a plurality of recesses 16. Each recess is axially aligned with one of the wells 15 so that a test tube 17 may be supported as illustrated in FIG. 6 with its lower end resting in the well and its intermediate or upper portion received within recess 16. When so supported, the tube slopes upwardly and rearwardly in a stable rest condition, being braced in that position by the upstanding back section 12. A plurality of such tubes may therefore be supported in spaced parallel relation. Most desirably, the shoulders 18 defining the open front of each recess are spaced closer together than the diameter d of that recess and, in particular, closer than the diameter d of tube 17 to be received therein (FIG. 7). Diameter d is, however, sufficiently larger than diameter d to provide a free sliding fit between tube 17 and recess 16. Therefore, a tube to be supported by the rack must be slid downwardly through recess 16 until its lower end is seated within well 15. When so supported, the tube is restrained against independent forward tipping movement.
An important aspect of the invention lies in the fact that the entire rack is formed of a single piece of flexible or bendable material. Whilethin metal might conceivably be used, plastic materials such as polystyrene have been found particularly effective. If plastic is used, the entire rack may be formed by vacuumforming or by any other suitable means from a single sheet of thin-gauge plastic. Following its formation, and prior to folding, the rack assumes the flat condition shown in FIGS. 4 and 5 with the flanges 13 and 14 of the same. plane. A fold line 19 defines the limits of the respective sections. As shown in FIGS. 4 and 5, line 19 is straight and extends between the rear of top wall 11b and the rear of bottom wall 12d, or what will eventually become the bottom wall 12d of the back section 12 when that section is folded into its upstanding position.
To maintain the rack in its erected condition, locking lugs and recesses are formed in the respective sections. In the form illustrated, four upstanding lugs are formed in the base section in close proximity to fold line 19. Mating recesses 21 are formed in back section 12. The width of each lug 20 is slightly greater than the width of the recess in which it is received. Consequently, when the rack is folded into its fully erected condition, a compressive force is exerted upon the lug and an expansive force upon the side walls of the recess to produce a tight locking fit between the parts (FIG. 8). While locking ribs may if desired be formed in the lugs to mate with corresponding grooves in the recesses, it has been found that a tight locking connection is effectively achieved by simply dimensioning the parts as described and by relying on the resilience of the material and the tensions produced therein.
The easeand speed with which the rack may be erected is believed particularly important in the clinical laboratory where time wasted in manipulating or assemblying separate parts to form a rack may have serious consequences for the patients whose tests are to be run. Since the two sections of the rack are integrally formed and are therefore interconnected along fold line 19, such sections are precisely oriented. for erection of the rack. A user, upon receiving the rack in flattened condition as illustrated in FIGS. 4 and 5, simply folds the sections together about line 19 until lugs 20 1. A disposable test tube rack comprising-a base section and a back section, said sections being integrally 7 formed from a single sheet of flexible plastic material are lodged tightly into recesses 21. The rack is then I readytor immediate use (FIG. 1).
While in the foregoing we have disclosed an embodiment of the invention in considerable detail for purposes of illustration, it will be understood by those skilled in the art that many of these details may be varied without departing from the spirit and scope of the invention.
and meeting along a transverse fold line, said base section having'aplurality of wells opening upwardly and being spaced apart in a transversely-extending series, said back section being foldable along said line between a shipping position wherein said back section lies along substantially the same horizontal plane as said base section and a raised position wherein said back section projects upwardly relative to said base section, said back section being provided with a transverse series of recesses positioned and arranged to align with said wells when said back section is raised, and cooperative locking means provided by said base and back sections for selectively locking said back section in its raised position.
2. The structure of claim 1 in which each of said recesses has a diameter slightly greater than the outside diameter of a test tube adapted to be received therein, said back section also providing a pair of shoulders spaced apart to define an opening into each of said recesses, the distance between each of said shoulders being less than the diameter of a tube slidably receivable in said recess, whereby, said shoulders are positioned and arranged to prevent tipping movement of a tube supported by said rack without restraining sliding movement of said tube through said recess into and out of a supported position.
3. The structure of claim 1 in which said locking means comprises a lug provided by one of said sections and a recess formed in the other of said sections, said lug and recess being equidistant from said fold line and being positioned and arranged to frictionally engage eflch other in mating relation when said back section is fully raised.
4. The structure of claim 3 in which said lug is wider than said recess to cause slight deformation of said recess and lug when the same are forced into interlocking relation.
5. The structure of claim 3 in which a plurality of pairs of lugs and recesses are provided by said sections in transversely-spaced relation.
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