This application pertains to a handling and packaging assembly, or system, for small diameter tubes and rods. It is particularly useful for the handling of small diameter (Outside diameter≦2 mm) tubes that have one end (the proximal end) tapered to a fine tip with the other end (the distal end) square cut. Such tubes find general application in the field of analytical chemistry, and most specifically in the field liquid chromatography-mass spectrometry. These tapered tubes, or needles, are typically used as ionization emitters in electrospray ionization mass spectrometry.
Traditionally capillary tubes or needles have been packaged in one of two ways:
These systems have significant shortcomings. The adhesives used in system (1) may chemically contaminate the tubes being shipped. This is not acceptable for applications in mass spectrometry, a chemical analysis method. Furthermore, the adhesives may deteriorate over time and loose holding power, damaging the tubes being stored.
System (2) is limited in its ability to protect the ends of the capillary tubes since the tubes may shift in the packaging tubes. Contact with at least one end of the capillary tube is typically unavoidable. The typical solution is to affix the distal end of each capillary tube to one of the end caps of the packaging tube, either with an adhesive or by the use of a rubber end cap that has an internal bore having an inside diameter less than the OD of the packaged tube.
A need therefore exists for an assembly which:
In accordance with the invention, there is now provided an assembly/system formed of functional components that provide for the processing, handling, storage, and shipping of groups, or arrays, of tubes. The core of the system is a holder 1 and holding clip 20 that uses a compression element 24 to hold the tubes 90 into the grooves 2 of holder 1. The holder 1 and holding clip 20, including the compressible element 24, and tubes 90, when assembled together, comprise a sub-assembly 15. Various other components and sub-assemblies interface with the combined holder 1, holding clip 20, and tubes 90. Different outside diameter tubes may be accommodated by either adjusting the depth of the grooves 2, the amount of compression applied by the element 24 or both. The compression element 24 is preferably a rectangular section of an elastomeric material, such as rubber, that is held normal to the top surface 3 of holder 1.
A loading system comprised of an alignment fixture 30, loading mount 40 and loading clip 50 enables the loading of a holder 1 and holding clip 20 with a population of tubes 90. The design of the loading system enables the loading of individual tubes onto the holder, the application of the holding clip 20 once the holder 1 is populated, and the subsequent removal of the combined holder 1, holding clip 20, and tubes 90 from the loading system. Loading clip 50 has a compression element 54 that is similar in form and substance to the compression element 24 used in the holding clip 20. However the mounting scheme for compression element 54 differs in that the compression element 54, which is preferably a piece of rectangular elastomeric sheet, such as rubber, is held at all acute angle with respect to the top surface 3 of the holder 1.
There is also provided a carrier transfer system which enables handling and processing operations to be carried out on the distal ends 93 of the tubes 90. The carrier transfer system allows the group of tubes 90 to be removed from the holder 1 and holding clip 20 while maintaining their respective alignment in an array. The carrier transfer system comprises a carrier body 60 and carrier clip 70. The carrier body 60 interfaces to the holder 1 and holding clip 20 in a reversible manner so that the group of tubes 90 may be released from the holder 1 and holding clip 20 or transferred to an empty holder 1 and holding clip 20. The transfer clip 70 is designed to protect the proximal end of the tube. It contains a compression element 74, which is similar in form and substance to compression elements 24 and 54, that is held normal to the surface 3 of holder 1.
Finally a package suitable for long-term storage and shipping of the holder 1, holding clip 20, and tubes 90 assembly, i.e., sub-assembly 15, is provided, so that the sub-assembly 15 may be placed directly into the package without the need to individually handle tubes. The package is designed to accommodate tubes that are either shorter in length than the holder 1 or longer than the holder 1 body.
Holding clip 20 has two protruding side arms 21, which are terminated by tapered mating elements 22 that mate with complementary tapered mating elements 9 on the flank sides of holder body 1. The tapered mating elements 9 on the flank sides of holder body 1 are disposed perpendicularly from the top surface and taper increasingly further away from the flank sides along the direction from the top surface towards the bottom surface. The distance between the two respective side arms 21 is set so that the clip has a direct positive engagement with the holder body 1, resulting in what is commonly referred to as a snap-fit. As the holding clip 20 is forced into place the arms 21 deflect as the faces of elements 9 and 22 make contact. Each side arm 21 aligns with the recessed slots 12 in the two flank sides of the holder body 1. As shown in
The amount of static (and dynamic) holding force is readily controlled by either changing the relative hardness of the elastomeric insert 24; and/or by altering the dimensions of the insert. Using an insert made from a higher durometer material will increase the holding force because the amount of reactive force generated by compressing the insert increases. Similarly making the elastomeric insert either thicker or taller will increase the holding force. Increasing the thickness of the insert increases the contact surface area of the elastomeric insert 24 with the tubes 90, hence the holding force will increase. By increasing the height of the elastomeric insert 24, the amount of elastomer that protrudes out of the slot 25 will increase. The holding force on tubes 90 will increase since the compression of the elastomeric insert 24 will be greater, creating a larger reactive holding force on the tubes 90. The thickness of the elastomeric insert may be within the range of 0.5 to 10 mm, preferably within the range of 1 to 5 mm, and most preferably within the range of 1.5 to 2 mm. The thickness of the elastomeric insert 24 and the height protruding from slot 25 is determined empirically so that a pull test of tubes 90 being held in subassembly 15 will yield a number within the preferred range for static and dynamic holding force. Changing the diameter of the tubes 90 will require a change in either hardness or dimension of elastomeric insert 24. Most conveniently the height of elastomeric insert 24 may be changed to bring the holding force within the desired range.
The holder body 1 optionally includes a slot 8 transverse to its bottom surface and holding clip 20 optionally includes holes 23 in each of the two side arms 21 which align with slot 8 when the clip is engaged with the holder body. Optional rod 26 may then be inserted through the holes 23 and under the holder body, via the slot 8, to further secure the holding clip 20 to holder body 1. The holder body 1 optionally includes through holes 6, in between protrusions 5, running parallel to the top face 3. The holes 6 can be used to hold or mount the holder body 1 on one or more mating cylindrical rods; or to manipulate holder body 1 using hand tools such as needle-nose pliers or forceps.
To load, or “populate”, holder body 1 with the array of tubes 90, the loading fixture assembly of
The initial assembly to populate a holder body 1 with tubes is shown in
The angled nature of the contact between elastomeric insert 54 and the tubes 90 results in the combination of sliding and static friction between the tubes and the elastomeric insert being different when the direction of movement of the tubes, with respect to the front of the mount is changed. The insertion force will be lower for pushing the distal end 93 of tube 91 in between groove 2 and elastomeric insert 54, than for the reverse operation. This characteristic makes the tubes easier to insert into the loading assembly and more difficult to remove. It has been found that these requirements can be met if the force required to initiate movement of the tubes in the assembly and the force necessary to maintain that movement, once initiated, fall within certain ranges.
There are two components to these force considerations:
The force required to initiate movement (the static force) of the tubes into the loading fixture assembly should be less than 1 N (Newton), preferably between 0.04 to 0.5 N, and the force required to maintain movement of the tubes into the loading fixture (dynamic force) should preferably be from less than 0.04 N up to about 0.2 N.
In accordance with the foregoing procedure, once the holder body 1 is fully populated with tubes 90, the (temporary) loading clip 50 may be replaced with the standard holding clip 20.
To insure maximum utility of the holder clip sub-assembly 15 as a multi purpose manufacturing process fixture and final packaging and presentation element, functional and ergonomic factors should be considered Environmental effects which may be encountered during shipping and handling should also be taken into consideration, in order to assure survivability during shipping and handling. With respect to the functional effects, the tubes 90 should be rigidly held in their respective grooves 2 and their alignment, especially the alignment of their ends, should be maintained as the sub-assembly 15 travels through a range of manufacturing processes, during which the sub-assembly 15 is exposed to a variety of shocks, vibrations, and inertial forces. Ergonomically, the size of sub-assembly 15 should be as compact as possible yet still addressable with a normal hand and finger size for ease of placement and manipulation of the capillary tubes during processing. Additionally, once assembled into the final packaging and shipped to the customer for use, it is important that the tubes 90 are able to be easily and efficiently extracted in serial fashion from either a right or left handed approach. All three elements of the clip holder sub-assembly 15 should be constructed to give the end user a comfortable and successful experience such that the human/device failure modes are minimized. It has been found that these requirements can be met if the force required to initiate movement of the tubes in the assembly and the force necessary to maintain that movement, once initiated, fall within certain ranges.
A preferred range of tensile force required (static force) to initiate tube movement (or conversely prevent movement) in the holder assembly 15 was found to be 0.04-3.0 N, preferably 1.0-1.6 N. A preferred range of tensile force (dynamic force) to maintain movement, once initiated, was found to be 0.04-2.8 N, preferably 0.8-1.4 N.
Carrier body 60 has additional features for holding of the tubes 90. A set of grooves 64 in top face 68 have identical shape, spacing and depth as the grooves 2 found in the holder body 1. In front of the grooves at the leading part of carrier body 60 there is a stepped-down top face 67 (best seen in
A carrier clip 70 has two side arms 75 that each have complementary mating elements 72 that mate with elements 62 on the carrier body 60. The spacing and shape between elements 72 is set so that the carrier clip 70 may be clipped into place on carrier body 60 in a manner completely analogous to that of the action of holding clip 20 on holder body 1. The bottom of carrier clip 70 is shown in
Insertion proceeds by first aligning the holder protrusions 5 parallel with the slot 61, holding the sub-assembly 15 at an acute angle with respect to the carrier body. Rear face 13 is pressed into contact with the rear face 66 of cavity 65, while ensuring that protrusions 5 are aligned to fit into the slot 61. Once in position, the angle between the sub-assembly 15 and carrier body 60 is reduced by rotating sub-assembly 15 through an axis defined by the contact of mating elements, 5 and 61, and, 13 and 66, until the compressive elements 63 make contact with the front face 14 of the holder body 1. The alignment between the holder body 1 and carrier body 60 is then made parallel when the compressive element 63 makes positive engagement with the detent 10 on the front face 14 of holder body 1 as shown in
The action of the carrier assembly is fully reversible so that tubes 90 in sub assembly 76 may be transferred back to sub assembly 15 by reversing the steps as described above.
For packaging storage and shipping sub-assembly 15 fits into sub assembly 85. Sub assembly 85 is a hinged box having a top wall, a bottom wall, two side walls, a front end and a rear wall which define the interior of the box. The box comprises a rear housing section 80, a front section 83 and a hinged lid 82, comprising a part of the top wall, as shown in
Hinged lid 82 is preferably transparent.
Preferably, between the hinges of said hinged lid 82 and the front side of box 85, the side walls are each comprised of two sections; a first section extending from the bottom surface of the box and a second section extending from the hinged lid, the two sections meeting each other to form a closed wall upon closure of the hinged lid.
Front section 83 has mating elements 81, which are snap-fit elements that engage with complementary elements 11 on holder body 1 (illustrated in
The lid 82 is integral with the front wall of the box and has bumps 88 that mate with complementary holes 89 on the side walls of front platform 83 as shown in
While the present invention was shown and described with reference to the preferred embodiments, various modifications will be apparent to those skilled in the art and, therefore, it is not intended that the invention be limited to the disclosed embodiment and/or details thereof, and departures can be made therefore within the spirit and scope of appended claims.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US07/63776 | 3/12/2007 | WO | 00 | 10/12/2009 |