HK1054178B - Lancet for sampling blood - Google Patents

Description

The invention relates to a lancet for blood collection, and in particular one with a metallic lancet needle contained in a plastic base part, from which a pointed end protrudes from the base part, embedded in a plastic headpiece moulded on the base part via a point of attachment, which can be removed from the base part before use when the needle end area is exposed when a rotational force is applied to one of the parts relative to the other part.

The headpiece, which contains the pointed end of the needle protruding from the base, ensures that the needle end is kept in a sterile environment until the use of the lancet. The previous practice in handling such lancets is to separate the headpiece from the base before using the lancet by twisting the headpiece to a certain extent against the base so that the point of attachment is cut off.However, practice has shown that the head of the lancet needle is often so firmly fixed in the head that the lancet needle is occasionally pulled out of the base during the described operation or the pulling forces are so great that if the needle is not exactly in the axial or longitudinal direction of the lancet needle, the needle may be quickly bent. Lancets of this type are generally used in conjunction with actuators that allow a person to move the needle into the skin in a mechanized manner for the purpose of drawing blood.It was found that when the head was removed, the base of the lancet, which was held in place by the control, was often removed from the control and the control was rendered unusable.

The purpose of the invention is to create a lancet of a kind suitable for the type in question, which allows the head part to be separated from the base part without undesirable or harmful effects on the lancet needle or problems in handling the lancet in operating equipment.

This is solved by the features of claim 1. In particular, a lancet with the design mentioned at the beginning has a cam guidance device placed between the headpiece and the base part, which, when a relative rotation is made between the headpiece and the base part, causes the headpiece to move axially relative to the base part. Instead of a more or less uncontrolled operation to remove the headpiece from the needle area, the cam guidance device ensures a controlled axial movement of the headpiece away from the base part, largely relieving the headpiece of axial forces during the pre- and separation of the lancet, since the headpiece is still supported on the base part in this operation.The removal of the needle from the base or base part of an actuator therefore avoids any concern. The cam guidance device also performs the function of a pinch guard which reliably prevents the needle end area from bending under external forces acting laterally on the headpiece. Although it has been proposed to provide a pinch guard on the headpiece to prevent the headpiece from deflecting laterally beyond a certain distance, the aforementioned problems of the hand grip of the lancet could not be solved.The cam guidance device may, according to a further development of the invention, comprise at least one pair of interlocking cams on the headform and at least one pair of interlocking cams on the baseform and on the headforms which interact with the headforms when rotated, with at least one pair of cams having cam guidance surfaces. The cams can be easily provided with the other structural features in the preferred single-piece training of the lancet in the plastic injection moulding process.

The following illustration and an embodiment of the invention show: Fig. 1 shows a lancet in one side, as shown in an embodiment of the invention, Fig. 2 shows a lancet in a similar view, Fig. 1 shows a lancet after 90° rotation, and Fig. 3 shows a lancet in a longitudinal view, as shown in Fig. 1.

The lancet according to the invention comprises a base part 1 and a head part 2 and a lancet needle contained in base part 1. The base part 1 and the head part 2 are connected to each other by means of a cutting or breaking point 4, see Fig. 3. The lancet is preferably an injection moulded part of a suitable plastic material such as a polyolefin, e.g. polypropylene or polyethylene, but other plastic materials may be used if desired. The cutting point 4 is designed so that it can be brought to a break under the influence of an external force to separate the head part 2 from the base part 1. The cutting point 4 may also be arranged in a form suitable for cutting or other forms of cutting, if it is designed to be arranged axially.

The lancet needle 3 embedded in base part 1 protrudes from base part 1 at one end with a pointed endpoint 5 . The lancet needle 3 is preferably made of a suitable metallic material such as steel material . The endpoint 5 is hermetically shielded from the outside environment in case of intact break point 4 in head part 2 . While the lancet needle 3 is held with a fixed seat in base part 1 , the endpoint 5 of the lancet needle 3 with a less fixed seat can be inserted into the cupil 2 so that the headpoint 2 can be separated from base part 1 from endpoint 5 of the lancet needle 3 without a significant force being exerted on the lancet needles 3 . However, as part of the invention, a fixed endpoint 5 of the lancet needle 3 also needs to be inserted into the headpoint .

A pair of cams 7 protrudes axially from a headpiece 6 of headpiece 2 towards the base part 1 and a pair of cams 9 protrudes axially from an opposite headpiece 8 of headpiece 1 towards the headpiece 2.

Each camshaft 7, 9 may have a pointed-gable configuration with a point on either side perpendicular to the respective front face 6, 8 of the head part 2 or base part 1 and camshaft 11, 11' or 12, 12' respectively. Facing camshaft 11, 12 of adjacent camshaft 7, 9 may interfere with each other at a relative rotation of the head part 2 relative to the base part 1 and cause a controlled axial movement of the head part 2 by pulling on the head part 2 in addition to a movement in the perimeter or rotation direction, an axial movement of the head part 1 is finally released by the force 1 when the respective axles are moved by at least 12 lanes 11 to 12 in succession. This force is then applied to the head part 2 without any further release of the head part 2 or 5 from the axle 2 without any further release of the head part 1 by the force 2 to 5 in the axle 2 direction, so that the head part 2 is released from the axle 2 without any further release of the head part 3 by the force 2 to 5 in the axle 2 direction.

The tip of each crest 7, 9 is also positioned at a certain axial distance from the respective opposite forehead 6 or 8 of head part 2 or base part 1 respectively. This creates an impact limit when the head part 2 is displaced laterally relative to the base part 1 or from an axially aligned relationship to the lancet needle 3. A lateral force, whether deliberately or unintentionally applied to the head part 2, can therefore only cause a limited lateral displacement of the head part 2 from the specified axial orientation. This displacement can be achieved by selecting an appropriate distance between the tip points of the head part 7, 9 and the respective forehead area 6, 8 so that the lancet 3, especially the head part 2, which is located on the head part 5 cannot be damaged by the effects of the impact.

The rest of the structure of the lancet is generally known to the expert, so that it is superfluous to describe the details in this respect.

The invention was described above by means of an embodiment in which the crankcase areas on the head and base are identically formed. However, the crankcase areas on the head could also be different from those on the base, for example, the crankcase areas on one of the parts are formed as in the previous embodiment and the crankcase areas on the other part may have the configuration of studs or supports that may protrude axially from the respective front face and be provided with rounded end surfaces. Furthermore, the crankcase conduction surfaces of the crankcase areas need not be axially rotating in both directions. Rather, a separation of the crankcase from the base face could be required to rotate the crankcase in a certain direction.The first description of the headform is a pair of crankcase areas, each with a 180° angle to the part concerned. Instead, more than two, e.g. three, crankcase areas may be arranged at 60° to each part. Finally, the cutting site may be so designed that it is cut off when a rotational force is applied to the headform before the crankcase areas enter into an axial motion-producing action, so that the crankcase areas essentially control only the axial motion of the crankcase relative to the base part. However, the cutting site may also be designed so that the cutting through of the crankcase area is completed or completed in conjunction with it.

Claims (4)

1. A lancet for the extraction of blood, including a lancet needle (3) of metallic material held in a base part (1) of plastics material, a pointed end portion (5) of said lancet needle protruding from said base part, said lancet needle being embedded in a head part (2) of plastics material being formed to the base part by a breaking zone (4) and adapted to be removed from the base part thereby exposing the pointed end portion of the lancet needle by exerting a rotational force to one of said base and head parts relative to the other, characterized by cooperating cam means (7,9) disposed between said head part (2) and said base part (1), said cam means engaging with each other upon relative rotation between the head and base parts for causing an axial movement of the head part relative to the base part.
2. The lancet according to claim 1, characterized in that said cam means comprise at least a pair of cam portions (7) provided on said head part (2) and offset with each other, and at least a pair of cam portions (9) provided on said base part (1) and offset with each other and also offset relative to the cam portions of said head part, said cam portions of the head and base parts engaging with each other during said rotation, whereby at least the cam portions of one said pairs of cam portions having cam guiding faces (11,11',12,12').
3. The lancet according to claim 1 or 2, characterized in that said cam portions (7,9) are effective for initiating an axial movement in at least one direction of said rotation.
4. The lancet according to one of the preceding claims, characterized in that said cam portions (7,9) have top ends spaced from an adjacent one of a facing end face (6,8) of the associated opposite part [base part (1) or head part (2)] in such manner that a lateral movement of one of said parts relative to the other from a coaxial alignment relative to the lancet needle (3) is limited.