referring to the drawing more particularly by reference numbers , fig1 shows a stopper 10 constructed according to the present invention . the stopper 10 is shown as being of unitary construction having an annular flange portion 12 and a smaller diameter tube - closing plug portion 14 . the flange portion 12 has an end face 16 which includes a centrally located depression or well 18 defined by tapered side and bottom surfaces 20 and 22 respectively . the flange 12 also has a frusto - conical outer surface 24 which extends from the end face 16 to its opposite end where it meets the outer periphery of radial face 26 . the flange portion 12 is larger in diameter than the plug portion 14 by a substantial factor typically by a factor of from about 1 . 4 to about 2 . 0 times . a preferred ratio of these diameters is about 1 . 7 . this preferred ratio enables a standard 10 millimeter collection tube to be used with a standard needle holder device having an inside diameter of from about 0 . 665 inch to 0 . 720 inch . at the juncture of flange and plug portions 12 and 14 an annular inwardly extending groove 28 is formed which enables the portions 12 and 14 to move angularly relative to each other to some extent thereby facilitating inserting and removing the plug portion 14 into a container or collection tube as will be described . the plug portion 14 is formed by an annular wall 30 which has an outer surface 32 that preferably has a slight end - to - end taper as shown to enable the plug portion 14 to be relatively easily and sealably inserted into the open end 34 of a container 36 such as the container shown in fig4 and 5 . the stopper 10 is preferably constructed of a relatively resilient material such as rubber or rubber like composition including thermoset rubbers such as butyl rubber , bromobutyl rubber , styrene butadiene rubber , nitrile butadiene rubber as well as thermoplastic rubbers such as polyester elastomer , styrene - base elastomer , polybutadiene or polyolyfin elastomer so that there is some give and compression of the plug portion 14 as it is inserted . any of the commonly used lubricating agents and mold release agents are suitable for use with the particular rubber composition selected to be used . also , additives can be employed in the stopper such as dyes , pigments , hemorepellants , and the like . it is also contemplated to have the free end of the plug portion 14 formed with an optional reduced diameter groove 37 to facilitate inserting the plug portion 14 into open end 34 of the container 36 . the plug portion 14 is annular in shape and has an inside surface 38 which terminates in a bottom or end surface 40 as clearly shown in fig1 . the bottom or end surface 40 is spaced from the bottom surface 22 of recess or well 18 formed in the end surface of the flange portion 12 , and it is preferred that the surface 22 which forms the bottom of the well 18 be at least as large in area , and preferably somewhat larger , than the area of the bottom surface 40 of recess 44 in the plug portion 14 . the portion 46 of the stopper 10 between the surfaces 22 and 40 can be referred to as the diaphragm portion of the stopper 10 , and is the portion through which a needle or other piercing instrument projects when the device is to be used to receive a blood or other sample during operation of the device as will be described more fully hereinafter . in fig4 the stopper 10 is shown mounted in the open end 34 of the tubular container 36 which container may be a small sample container or test tube . the container 36 has a side wall 48 which is shown as tubular in shape terminating in a closed end wall 50 . the inner surface 52 of the container 36 is sized to slidably and sealably receive the plug portion 14 of the stopper 10 when the stopper is pressed or twisted therein . the stopper 10 is usually pressed into the open end 34 of the container 36 until the end 54 of the container bears against the surface 26 on the flange portion 12 of the stopper . insertion of the plug portion 14 into the container can take place during manufacture in which case the stopper and the container including especially the interior of the container are sterilized and may be partially evacuated leaving a vacuum condition therein . furthermore , the stopper 10 should not be so tight - fitting in the container 36 as to be difficult to remove since the stopper may be required to be removed by a technician or other person in order to extract the blood or other sample contained therein for some purpose , although it is also contemplated to remove the sample by means of another needle on an extraction device . removal of the stopper 10 from the container 36 is facilitated by having the flange portion 12 relatively large in diameter for ease of grasping and twisting . by having the flange portion relatively large and easy to grasp it effectively isolates the open end 34 of the container 36 from the fingers of the remover . also , the larger flange portion makes it less likely that the person removing the stopper will lose control and spill the contents including spilling the contents onto his or her skin or clothing . the subject stopper , and the container in which it is installed , are designed to be used in association with a holder device such as the holder device 56 as shown in fig5 . the holder device 56 is shown including an elongated tubular portion 58 closed at one end by wall 60 and having an outwardly extending flange portion 62 at the opposite end . the closed end wall 60 has a central portion 64 which supports a double ended needle member 66 which is shown having a portion 68 extending inside the holder 56 and a portion 70 extending from the end of the holder . both ends 72 and 74 of the needle 66 are open and both are tapered as shown to facilitate their penetration into the stopper or into skin of a patient with which they come in contact . the tubular portion 58 of the holder 56 has a cylindrical inner surface 76 which is sized to slidably receive the tapered flanged portion 12 of the stopper 10 when the stopper and the container on which it is installed are inserted into the holder 56 as shown in fig5 . ideally the container 36 and the holder 56 should be in axial alignment when the container is inserted but this may not always be the case especially when the insertion is made while the end portion 70 of the needle 66 is inserted into the vein of a patient from whom a blood sample is being removed . it is important to the operation of the present device however , that whether the members 36 and 56 are in precise axial alignment or not that the inner end portion 68 of the needle 66 engage and pierce the diaphragm portion 46 of the stopper 10 and in so doing will pass therethrough and enter the container 36 somewhere in the region defined within the cavity or plug well portion 44 . in other words , regardless of the angle at which the needle portion 68 engages and pierces the stopper 10 it should not be possible for the needle to pierce the stopper so as to penetrate the annular portion 30 of the plug portion 14 . this assures that the piercing end 72 of the needle 66 will never be blocked or occluded when a blood sample is being taken from the vein or artery of a patient . this is especially important when using small diameter collection tubes since the likelihood of blocking or occluding the end 72 of needle 66 increases substantially when relatively small collection containers or tubes are used with correspondingly small stoppers , such , for example , as 10 millimeter blood collection tubes in holders that are constructed to accomodate larger collection tubes such as 16 millimeter collection tubes . in a typical application a single holder device 56 is therefore able to receive different size collection tubes even while the opposite end portion 70 of the needle 66 remains inserted into a patient &# 39 ; s vein . this means that once the needle has been inserted into a vein the containers into which the blood being drained is collected can be changed in order to allow the blood to flow into several different containers from the patient . furthermore , changing from one size container to another can be accomplished with minimal blood loss and with minimal possibility that the blood being taken will come into contact with the technician , doctor , or nurse performing the procedure . these are important considerations and mean that blood samples of different sizes can be taken from the same patient without having to reinsert the needle into the patient for each sample and without causing the patient additional discomfort . the construction of the present stopper also protects against the one taking the samples piercing the stopper in a manner which will obstruct the blood flow , and this is true regardless of the angle at which the container is inserted into the holder device . all of these are important features and advantages and ones which are available when using the present construction . in a typical situation it has been found that the outside diameter at the widest point on the flange 12 should be between about 1 . 4 and about 2 . 0 times the diameter of the plug portion 14 at its widest point , and the surface 22 should be substantially larger than the surface 40 , and should be such as to assure that the needle will be properly located to penetrate the stopper regardless of the various possible angles of the container 36 when inserted into the holder 56 . in the case of a typical 10 millimeter blood collection tube having an inside diameter of about 9 . 85 millimeters , the outside diameter of the flange portion 12 should be in the range from about 1 . 6 to about 1 . 8 times the inside diameter of the collection tube 36 , i . e . from about 15 . 8 to about 18 . 0 millimeters , and preferably between about 16 . 8 to 17 . 8 millimeters . such dimensions assure proper guidance and alignment of the collection tube 36 fitted with such a stopper 10 and the successful penetration of the needle portion 68 into and through the diaphram portion 46 of the stopper . it should also be noted that as the diameter of the collection tube becomes smaller in relation to the diameter of the holder 56 there is a greater chance for trouble when using the device . this is especially true when inserting a 10 millimeter collection tube into a standard holder which has an inside diameter of about 0 . 720 inch at the open end thereof . not only is the alignment of the needle an important consideration , particularly when using relatively small diameter containers and stoppers , but if the point at which the needle 66 initially penetrates is in a sloping wall portion of the stopper as for example in wall portion 20 , it may develop what is known as &# 34 ; point roll &# 34 ; which is a condition that tends to deflect the needle sidewardly and outwardly toward the side wall 30 of the plug portion 14 . if a relatively thin - walled needle of small guage is used , &# 34 ; point rolling &# 34 ; may deflect an originally straight needle to such an extent that the free end thereof engages the wall 30 and is blocked or becomes occluded or moves into the side wall 30 of the plug portion 14 . any of these conditions can produce a &# 34 ; no vacuum &# 34 ; effect and prevent or at least discourage movement of the blood from the patient into the collection tube 36 . such a condition may also require that the container 36 be withdrawn from the holder so that the needle will be withdrawn to enable another penetration to take place before the device will operate properly . the possibility of &# 34 ; point roll &# 34 ; is further obviated in the present construction by having the bottom wall portion 22 of the outer recess or well 18 made relatively large and flat so that the needle will not be as likely to attempt to enter at a sloping wall portion of the stopper . consequently , the &# 34 ; point roll &# 34 ; condition is largely overcome by the construction of the present stopper . it should also be kept in mind that with the present construction the amount of possible angular movement between the stopper 10 and the holder member 56 into which it is positioned is limited by the size and shape of the collection tube 36 and to some extent by the length of the collection tube . the important thing is that the varied possible angular positioning of the stopper be such that the needle will never be able to enter the stopper so as to produce the undesirable conditions set forth above . thus there has been shown and described a novel stopper construction for use with medical containers , and especially with blood collection tubes and the like which fulfills all of the objects and advantages sought therefor . it will be apparent to those skilled in that art , however , that many changes , modifications , variations , and other uses and applications for the subject stoppers are possible and contemplated . all such changes , modifications , variations , and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow .
a stopper for medical containers such as blood collection tubes having integral flange and plug portions , the flange portion being substantially larger in diameter than the plug portion , which plug portion is sized to sealably close the container . the stopper has opposed wells formed in the flange and plug portions , the well in the flange portion having a relatively flat bottom surface at least as large in diameter as the diameter of the opposed well in the plug portion . the flange portion is constructed to be guided into a tube holder into which it is inserted such that one end of a needle projecting into the interior of the tube holder will penetrate the stopper in the area of the opposed wells so as to avoid otherwise contacting the stopper . the enlarged flange portion also serves to facilitate removal of the stopper from the container without contaminating a handler .