turning now to fig1 there is shown a latching and sealing device 10 disposed within a glass tube , or bore , 12 having an inside surface 14 . medical or laboratory equipment for which the present invention is intended for use typically utilizes glass tubes having inside diameter of about 0 . 015 to about 0 . 020 inches . shown in a partially broken perspective view in fig1 the latching and sealing device 10 generally includes a cylindrical seal member 20 , a cylindrical core , or piston , 22 and a spring 24 . for use in laboratory equipment , the cylindrical seal member 20 is preferably formed from polytetrafluoroethylene , or the like , and generally consists of a body portion 26 and a lip - and - latch portion 28 which provides means for sealably engaging the surrounding surface 14 and latching the cylindrical seal member 20 to the cylindrical core 22 . as hereinafter discussed in greater detail , the lip - and - latch 28 includes a groove 34 formed on an inside surface 36 of the lip - and - latch 28 which provides a means for supporting the spring 24 therein . the lip - and - latch 28 flexibly depends from the body 26 and the thickness and shape thereof enable the lip - and - latch 28 to exert an outward radial force against the surface 14 and also enable assembly of the latching and sealing device 10 as hereinafter described . to enhance the sealing between the seal member 20 and the surface 14 , a raised portion , or circumferential berm , 38 may be formed on the lip - and - latch which provides means for concentrating the sealing pressure between the lip - and - latch and the surrounding surface 14 produced by the spring 24 . in addition , to provide for a supple engagement between the berm 38 and the surface 14 , the berm 38 may have notches 42 therein which provide tapered projections 44 on the berm 38 which are easily deformed by the pressure between the lip - and - latch 28 and the surface 14 , thereby facilitating the seal therebetween . the cylindrical core 22 includes a circumferential groove 48 therein which provides means for supporting the spring 24 between the lip - and - latch 28 and the cylindrical core 22 . in addition , the cylindrical core 22 includes an end portion , or tip 50 , which provides a means for both coaxially aligning the seal member 20 onto and with the cylindrical core 22 and for locating the spring 24 thereon for engagement by the lip - and - latch groove 34 to enable assembly of the latching and sealing device 10 as hereinafter described . maintaining alignment between the seal member 20 and the cylindrical core , or piston , 22 , is important since skewing of the seal member 20 within the bore 12 jeopardizes the security of the seal therebetween and may inhibit movement of the piston 22 . axial locking between the seal member 20 and the cylindrical core 22 is ensured by two locking surfaces 54 , 56 disposed generally parallel to one another and in planes generally perpendicular to the axis 60 of the cylindrical core 22 . upon assembly of the latching and sealing device 10 , the spring 24 snaps into the groove 48 and is prevented from moving thereout of by the locking surfaces 54 , 56 . this allows the cylindrical core , or piston , to move within the bore 12 while maintaining a seal therebetween through the cylindrical seal member 20 . similarly , an inside surface 64 of the groove 34 prevents a separation of the spring from the lip - and - latch 28 . in order to provide constant radial force between the lip - and - latch 28 and the surface 14 , the spring 24 may be of a continuous torroidal - type including a plurality of canted coils 70 for providing a constant force over a preselected range of deflection . a full description of this type of spring is set forth in u . s . pat . no . 4 , 655 , 462 issued apr . 7 , 1987 , which is incorporated herewith by specific reference thereto . fig2 a , b and c show assembly of the latching and sealing device 10 before insertion into the bore 12 . as hereinbefore pointed out , the cylindrical core 22 includes an end portion , or tip , 50 for supporting the spring at 24 , as shown in fig2 a . it should be appreciated that the diameter of the tip portion 50 , which is greater than the inside diameter of the torroidal - type spring 24 when it is in a relaxed condition , in order that the tip 50 slightly expands the spring 24 when in the position as shown in fig2 a . in addition , the cylindrical core includes a ramp portion 72 for radially compressing the spring 24 into the groove 34 to enable assembly of the latching and sealing device 10 . this compression is more clearly shown in fig2 b , which illustrates an intermediate position before the spring reaches its final position , as illustrated in fig2 c . it should be appreciated that the lip - and - latch 28 depending from the body 26 fo the seal member 20 has sufficient flexibility to radially expand , if necessary , when engaged by the spring 24 during assembly of the latching and sealing device 10 in order to enable such assembly without exceeding the elastic limit of the spring 24 , thus causing unwanted permanent deformation thereof . fig3 a , b and c show an alternative embodiment 80 of the present invention in which the latching and sealing device includes a seal member 82 having a body 84 and a lip - and - latch 86 , the lip - and - latch having a first and a second groove 90 , 92 therein for accommodating a first and a second spring 94 , 96 . similarly , the cylindrical core 100 has first and second circumferential grooves 104 , 106 and the berm 108 includes spaced - apart notches 110 , 112 . the lip - and - latch 86 , grooves 90 , 92 , 104 , 106 , springs 94 , 96 and core 100 as well as the notches 110 , 112 , operate in a manner as hereinbefore described in connection with the previously described latching and sealing device 10 . the core 100 includes an end portion 116 for both coaxially aligning the cylindrical seal 82 with the core 100 and for locating the first and second spring 94 , 96 , for engagement by the lip - and - latch grooves 90 , 92 during assembly of the latching and sealing device 80 . importantly , the first core groove 104 includes a ramp 118 , which provides means for radially compressing the first and second springs 94 , 96 , as hereinbefore described in connection with the latching and sealing device 10 to enable assembly of the latching and sealing device 80 , a locking surfaces 120 , 124 in the first core groove 104 and locking surfaces 126 , 128 in the second core groove 106 prevent axial movement between the seal member 82 and the core 100 after assembly . in addition to increasing the amount of available pressure between the seal member 82 and an inside bore surface , not shown , the two spring configuration adds additional locking between the seal member 82 and the core 100 . the lip - and - latch 86 , having a larger berm 108 thereon , provides for increased surface engagement for sealing than the latching and sealing device 10 . because the seal member 82 is locked to the core 100 , it may be placed at any position within a bore and thereafter withdrawn without separation therebetween , thereby enabling the bore to be sealed and unsealed at any preselected location . although there has been described hereinabove a specific latching and sealing device in accordance with the present invention for the purpose of illustrating the manner in which the invention may be used to advantage , it should be appreciated that the invention is not limited thereto . accordingly , any and all modifications , variations , or equivalent arrangements , which may occur to those skilled in the art , should be considered to be within the scope of the invention as defined in the appended claims .