HOLLOW NEEDLE FOR A SAMPLE PIPETTOR

Abstract

A hollow needle for piercing a closure of a sample vessel, wherein the hollow needle has a cylindrical hollow profile extending along a longitudinal axis and having a tip at a first end thereof, where the hollow needle has a first section that has a tip and a second section that has a larger diameter than the first section, and a transition between the first section and the second section has at least one cutting edge that extends from the first section to the second section.

Claims

1. A hollow needle (1) for piercing a closure of a sample vessel, wherein the hollow needle (1) comprises a cylindrical hollow profile extending along a longitudinal axis (L) and having a tip (2; 20) at a first end thereof, wherein the hollow needle (1) has a first section (10) which encompasses the tip (2; 20) and wherein the hollow needle (1) has a second section (11) which has a larger diameter than the first section (10), characterized in that a transition (3) between the first section (10) and the second section (11) comprises at least one cutting edge (30) which extends from the first section (10) to the second section (11).

2. The hollow needle (1) according to claim 1, wherein the transition (3) comprises two or more cutting edges (30) extending from the first section (10) to the second section (11).

3. The hollow needle (1) according to claim 1, wherein the cutting edges (30) are evenly distributed around the circumference of the transition (3).

4. The hollow needle (1) according to claim 1, wherein the cutting edges (30) extend substantially perpendicular to the longitudinal axis (L) or wherein the cutting edges (30) extend at an angle of less than 90 to the longitudinal axis (L).

5. The hollow needle (1) according to claim 1, wherein each cutting edge (30) is formed by two flanks (31, 32) adjacent thereto, wherein the two adjacent flanks (31, 32) extend at an equal angle to the longitudinal axis (L) or the two adjacent flanks (31, 32) extend at different angles to the longitudinal axis (L).

6. The hollow needle (1) according to claim 1, wherein the tip (2) comprises a first surface (200) which extends at an angle to the longitudinal axis (L) over substantially the entire cross-section, or wherein the tip (20) comprises a first surface (200) and a second surface (201) which extend at an angle to the longitudinal axis (L) over substantially half of the cross-section.

7. The hollow needle according to claim 6, wherein the flanks (31, 32) of the cutting edge (30) are aligned along the longitudinal axis (L) with the surfaces (200, 201) of the tip (2; 20).

8. The hollow needle according to claim 7, wherein a first flank angle (310) of the cutting edge (30) substantially corresponds to an edge angle (2050) of the tip (2) or a second surface angle (2010) of the tip (20), and wherein a second flank angle (320) of the cutting edge (30) substantially corresponds to a first surface angle (2000) of the tip (2; 20).

9. The hollow needle (1) according to claim 6, wherein the tip (2; 20) has an opening (130) which is provided in the first surface (200) or which is provided adjacent to the first surface (200).

10. The hollow needle (1) according to claim 1, wherein in the second section (11) at least one recess (4) is provided, which extends substantially along the longitudinal axis (L) over at least a region of the second section (11).

11. The hollow needle (1) according to claim 10, wherein two or more recesses (4) are provided in the second section (11), which are evenly distributed around the circumference of the second section (11).

12. The hollow needle (1) according to claim 1, wherein the hollow needle (1) comprises a third section (12), which adjoins the second section (11) on the side of the second section (11) opposite the first section (10).

13. The hollow needle (1) according to claim 12, wherein the third section (12) comprises a stop (6) which projects beyond the diameter of the second section (11) and which is spaced from a second end opposite the first end of the hollow needle (1).

14. The hollow needle (1) according to claim 1, wherein the hollow needle (1) comprises an inner tube (5) and an outer tube (6), wherein the inner tube (5) extends over the entire length of the hollow needle (1) and the tip (2; 20) is formed in the inner tube (5), and wherein the outer tube (6) extends around the inner tube (5) at least over a region of the second section (11).

15. The hollow needle (1) according to claim 14, wherein the at least one cutting edge (30) is formed in the outer tube (6).

16. The hollow needle (1) according to claim 14, wherein the hollow needle (1) comprises a connecting tube (7) which adjacent to the outer tube (8) extends to the second end of the hollow needle (1) around the inner tube (5).

17. The hollow needle (1) according to claim 1, wherein the tip (2; 20) comprises at least one cutting edge (203; 204) and the at least one cutting edge (30) of the transition (3) is aligned with the at least one cutting edge (203; 204) of the tip (2;20).

Description

DESCRIPTION OF THE FIGURES

[0029] Embodiment examples of the present invention are explained in more detail below using Figs. These are for explanatory purposes only and are not to be interpreted restrictively, wherein:

[0030] FIG. 1 shows a side view of a hollow needle according to the invention;

[0031] FIG. 2 shows a sectional view through the hollow needle of FIG. 1;

[0032] FIG. 3A shows a view of detail V of FIG. 1;

[0033] FIG. 3B shows a view of detail X of FIG. 2;

[0034] FIG. 3C shows a rear view of FIG. 3A;

[0035] FIG. 4 shows a view of the detail Y of FIG. 2;

[0036] FIG. 5 shows a view of section B-B of FIG. 2;

[0037] FIG. 6A shows a view of the detail W of FIG. 3C;

[0038] FIG. 6B shows a detailed view of the tip of FIG. 3B;

[0039] FIG. 6C shows a rear view of FIG. 6A;

[0040] FIG. 7A shows a sectional view of a hollow needle according to the prior art;

[0041] FIG. 7B shows a sectional view of a hollow needle according to the invention;

[0042] FIG. 8A shows a detailed view of an alternative hollow needle tip;

[0043] FIG. 8B shows a sectional view of the hollow needle tip of FIG. 8A;

[0044] FIG. 8C shows a rear view of FIG. 8A;

[0045] FIG. 9A shows a sectional view of a hollow needle according to the prior art;

[0046] FIG. 9B shows a sectional view of a hollow needle according to the invention; and

[0047] FIG. 10 shows the steps for inserting a hollow needle according to the invention into a sample pipettor.

DETAILED DESCRIPTION OF THE INVENTION

[0048] FIG. 1 shows a side view of a hollow needle according to the invention and FIG. 2 shows a sectional view through the hollow needle of FIG. 1. The hollow needle 1 comprises a cylindrical hollow profile which extends along a longitudinal axis L and at the first end of which a tip 2 is provided. The hollow profile can have a circular, oval or n-angular cross-section, wherein n is equal to or greater than or equal to three. The n-angular cross-section can be a regular or irregular n-angle. The hollow needle 1 has a first section 10, which includes the tip 2. The hollow needle 1 also includes a second section 11, which has a larger diameter than the first section 10. A transition 3 between the first section 10 and the second section 11 comprises at least one cutting edge 30 extending from the first section 10 to the second section 11. In the embodiment shown, the hollow needle 1 further comprises a third section 12 which adjoins the second section 11 and extends opposite the first end to the second end of the hollow needle. The length of the first section 10 is a multiple of the diameter of the first section 10 and the length of the second section 11 is a multiple of the diameter of the second section 11 and is a multiple of the length of the first section 10. The length of the third section 12 is a multiple of the length of the first section 10 and a fraction of the length of the second section 11. In a central area of the second section 11, several recesses 4 are evenly distributed around the circumference.

[0049] The end of recesses 4 directed towards the tip 2 is spaced from the cutting edge 30 and the end of recess 4 directed away from the tip 2 is spaced from the third section 12. The third section 12 has a diameter only slightly larger than the second section 11. The third section 12 comprises a connecting tube 7 which extends from the second section 11 to the second end of the hollow needle 1. In the third section 12 a cone 70 is formed at the second end of the hollow needle 1. The third section 12 includes a stop 8, the diameter of which is larger than that of the connecting tube 7, and the width of the stop 8 is essentially equal to its length. The distance between the stop 8 and the second end of the hollow needle 1 is several times the length of the stop 8. The hollow needle 1 comprises an inner tube 5 which extends from the first end, i.e. from the tip 2, to the second end, i.e. to the cone 70. The tip 2 surrounds the first end of the inner tube 5. The hollow needle 1 further comprises an outer tube 6, which extends in the second area 11 around and adjacent to the inner tube 5. The recesses 4 are formed in the outer tube 6. The hollow needle 1 further comprises a connecting tube 7, which extends in the third area 12 around the inner tube 5 and adjacent to it. The stop 8 is designed as a sleeve, which extends around the connecting tube 7 and lies against it. The inner tube 5, the outer tube, 6, the connecting tube 7 and the stop 8 are firmly connected to each other by laser welding.

[0050] FIG. 3A shows a view of detail V of FIG. 1, FIG. 3B shows a view of detail X of FIG. 2 and FIG. 3C shows a rear view of FIG. 3A. The figure shows the first section 10 and a part of the second section 11 with a part of the recesses 4. The cutting edge 30 and a first flank 31 is visible of the transition 3. The cutting edge 30 extends essentially perpendicular to the longitudinal axis L of the hollow needle. The first flank 31 is produced by grinding the outer tube 6 at an angle before assembling it with the inner tube 5. In the interior of the inner tube 5, a hollow channel 13 extends over its entire length. The first flank 31 extends at a first angle 310 from the cutting edge 30 obliquely in the direction of the second end of the hollow needle 1. A second flank 32 extends at a second angle 320 from the cutting edge 30 obliquely in the direction of the second end of the hollow needle 1. In this illustration, the first angle 310 is a multiple of the second angle 320. The ends of the recesses 4 directed towards the transition 3 are spaced from the edge of the first and second flanks 31, 32 directed towards the second end of the hollow needle 1.

[0051] FIG. 4 shows a view of detail Y of FIG. 2. The inner tube 5 with the hollow channel 13 extends along the longitudinal axis L. The outer tube 6 surrounds the inner tube 5 in the second section 11 and the connecting tube 7 surrounds the inner tube 5 in the third section 12. The connecting tube 7 is flush with the outer tube 6. The stop 8 surrounds an area of the connecting tube 7. The wall thickness of the stop 8 is greater than the wall thickness of the connecting tube 7.

[0052] FIG. 5 shows a view of section B-B of FIG. 2, showing a section through the area of the recesses 4 in the second area 11 of the hollow needle 1. Six recesses 4 are evenly distributed around the circumference of the outer tube 6. The depth of the recesses 4 is greater than half the wall thickness of the outer tube 6, and the wall thickness of the outer tube 6 is a multiple of the wall thickness of the inner tube 5.

[0053] FIG. 6A shows a view of the detail W of FIG. 3C, FIG. 6B shows a detail view of the tip of FIG. 3B, and FIG. 6C shows a rear view of FIG. 6A. The tip 2 of hollow needle 1 comprises a first surface 200, which extends at a surface angle 2000 with respect to the longitudinal axis L. The first surface 200 can be created by grinding the inner tube 5.

[0054] On the opposite side of the first surface 200 with respect to the longitudinal axis L, a second surface 201 and a third surface 202 are provided, wherein the second surface 201 is arranged at an angle to the first surface 200 and the third surface 202. A first edge 203 is formed by the intersection line of the first surface 200 with the second surface 201, a second edge 204 is formed by the intersection line of the first surface 200 with the third surface 202, and a third edge 205 is formed by the intersection line of the second surface 201 with the third surface 203. The third edge 205 extends at an edge angle 2050 with respect to the longitudinal axis. When the tip 2 is inserted into the closure, first radial forces act on the hollow needle 1 from the side of the first surface 200. The design of the second surface 201, the third surface 202, together with the third edge 205, generate second radial forces in a direction opposite to the direction of the first forces. The tip 2 of the hollow needle 1 is accordingly less pushed to the side, allowing the hollow needle to be inserted in a more centered manner into a sample vessel. The hollow channel 13 extends through the entire inner tube 5 and opens into an opening 130, which is enclosed by the first surface 200.

[0055] FIG. 7A shows a sectional view 9 of a hollow needle according to the prior art, as is produced when a tip, as shown in FIGS. 6A to 6C, is pushed through a closure. A first section 90 is cut into the closure by the first cutting edge 203 and a second section 91 is cut into the closure by the second cutting edge 204. The outer ends of the first and second sections 90, 91 are at a diameter corresponding to that of the first section 10 and the inner tube 5 respectively. If the second section 11 or the outer tube 6 is to be pushed through the closure, sections 90, 91 must be widened, creating radial clamping forces which act on the hollow needle. The increased radial forces also increase the force required to push the hollow needle through the closure or to pull the hollow needle out of the closure.

[0056] FIG. 7B shows a sectional view of a hollow needle according to the invention, as it is produced when the tip is first pushed through the closure according to FIGS. 6A to 6C and then the transition 3 with two cutting edges 30 opposite each other on the circumference, as shown in FIG. 3A. The tip 2 again creates a first section 90 and a second section 91. When the transition 3 is pushed through the closure, the cutting edges 30 create a third section 92, which adjoins the first section 90, and a fourth section 93, which adjoins the second section 91. The outer ends of the third and fourth section 92, 93 are on a diameter corresponding to that of the second section 11 or the outer tube 6 respectively. When the transition 3 is pushed through the closure, its cutting edges 30 produce cutting forces, but these are less than the forces needed to expand the closure if there are no cutting edges 30. Because all sections 90, 91, 92, 93 together extend over essentially the diameter of the second section, the forces required to expand the closure are much smaller.

[0057] FIG. 8A shows a detailed view of an alternative hollow needle tip 20, FIG. 8B shows a sectional view of the hollow needle tip 20 of FIG. 8A and FIG. 8C shows a rear view of FIG. 8A. In this embodiment, the first section 10 or the inner tube 5 is compressed and then ground off from two sides symmetrically with respect to the longitudinal axis L. This results in a first surface 200 and a second surface 201. The first surface 200 is oriented at a first surface angle 2000 with respect to the longitudinal axis L and the second surface 201 is oriented at a second surface angle 2010. The intersection line of the first surface 200 with the second surface 201 results in the first edge 203. Alternatively, two first surfaces 200 and two second surfaces 201 could be ground to tip 20, wherein the two first surfaces 200 are oriented at an angle with respect to each other and wherein the two second surfaces 201 are oriented at an angle with respect to each other. This creates two first edges 203, which are oriented at an angle with respect to each other. A symmetrical arrangement and orientation of the first and second surfaces results in a symmetrical arrangement and orientation of the first edges. In the tip 20 shown, the hollow channel 13 opens into an opening 130, which is located adjacent to the first surface 200.

[0058] FIG. 9A shows a sectional view of a hollow needle according to the prior art. The tip 20 shown in FIGS. 8A to 8C cuts only a central fifth section 94 into the closure. The fifth section 94 extends essentially over the diameter of the first section 10, or inner tube 5. By compressing the inner tube 5, the tip 20 is widened at its end, causing the first cutting edge 203 to protrude over the diameter of the inner tube 5.

[0059] FIG. 9B shows a sectional view of a hollow needle according to the invention.

[0060] Through the cutting edges 30 of transition 3, a third section 92 and a fourth section 93 are cut into the closure, wherein the third and fourth sections 92, 93 are laterally adjacent to and aligned with the central fifth section 94. FIG. 10 shows the steps for inserting a hollow needle 1 according to the invention into a sample pipettor 100. The sample pipettor 100 comprises a holder 101 with a connecting sleeve 102, in which a tube 103 is slidably mounted, and a union nut 104, with which the hollow needle can be attached to the holder 101. For pipetting, negative or positive pressure can be generated in tube 103. The holder 101 can be moved horizontally and vertically. The connecting tube 7 of the hollow needle 1 is inserted with the cone 70 into the tube 103. The tube 103 is pushed together with the hollow needle 1 into the connecting sleeve 102 up to the stop 8. The union nut 104 is pushed from the tip 2 over the hollow needle 1 up to the stop 8 and the union nut 104 is screwed tight on the connecting sleeve 102.

TABLE-US-00001 LIST OF REFERENCE NUMERALS 1 Hollow needle 10 First section 11 Second section 12 Third section 13 Hollow channel 130 Opening 2 Tip 20 Tip 200 First surface 2000 First surface angle 201 Second surface 2010 Second surface angle 202 Third surface 203 First edge 204 Second edge 205 Third edge 2050 Edge angle 3 Transition 30 Cutting edge 31 First flank 310 First angle 32 Second flank 320 Second angle 4 Recess 5 Inner tube 6 Outer tube 7 Connecting tube 70 Cone 8 Stop 9 Sectional view 90 First section 91 Second section 92 Third section 93 Fourth section 94 Fifth section 100 Pipettor 101 Holder 102 Connection 103 Tube 104 Union nut L Longitudinal axis