Hand-held medical device
View Patent ↗Disclosed herein are hand-held medical devices, such as blood glucose meters, that include a housing with a cassette compartment for receiving an exchangeable test tape cassette, a drive assembly comprising an electric motor and a gear arrangement adapted for rotating a tape spool of the test tape cassette, where the gear arrangement has a worm drive in which a worm meshes with a worm wheel and a multistage speed-reducing unit comprising a plurality of spur gears arranged between the worm wheel and an output gear that can be directly coupled to the tape spool.
1. A hand-held medical device comprising:
a housing with a cassette compartment;
an exchangeable test tape cassette received in the cassette compartment; and
a drive assembly comprising an electric motor and a gear arrangement adapted for rotating a tape spool of the test tape cassette, wherein a test tape of the test tape cassette can be wound forwards and test elements thereon can be provided for successive use, wherein the gear arrangement has a worm drive in which a worm meshes with a worm wheel and a multistage speed-reducing unit comprising a plurality of spur gears arranged between the worm wheel and an output gear directly coupled to the tape spool, wherein each of the plurality of spur gears has at least about 10 teeth, and wherein the worm is directly mounted on a motor shaft of the electric motor.
2. The medical device of claim 1 , wherein the multistage speed-reducing unit has at least two meshing gear pairs for reducing rotational speed between the worm drive and the output gear.
3. The medical device of claim 1 , wherein the output gear has about 60 teeth, and wherein the electric motor and the output gear have a speed reduction ratio of at least about 300.
4. The medical device of claim 1 , wherein the output gear has about 60 teeth, and wherein the electric motor and the output gear have a speed reduction ratio of at least about 400.
5. The medical device of claim 3 , wherein the output gear can provide a torque on the tape spool of at least about 20 mNm.
6. The medical device of claim 1 , wherein the test tape cassette further comprises a first tape spool for unused tape, a second tape spool for used tape, and a seal through which the test tape is transported between the first spool and the second spool, and where the output gear is acting on the second spool.
7. The medical device of claim 1 , wherein the worm drive is self-locking such that the worm wheel cannot drive the worm when a torque is exerted on the tape spool.
8. The medical device of claim 7 , wherein the torque exerted on the tape spool is at least about 10 mNm.
9. The medical device of claim 7 , wherein the torque exerted on the tape spool is at least about 14 mNm.
10. The medical device of claim 1 , wherein rotational axes of the plurality of spur gears are parallel to a rotational axis of the tape spool.
11. The medical device of claim 1 , wherein a rotational axis of the electric motor is skewed or perpendicular to rotational axes of the plurality of spur gears.
12. The medical device of claim 1 , wherein the plurality of spur gears comprise overlapping pairs of stepped wheels.
13. The medical device of claim 1 , wherein the plurality of spur gears are arranged in a non-linear configuration, such that centers of the spur gears span a polygon selected from the group consisting of a triangle and a quadrangle.
14. The medical device of claim 1 , wherein the drive assembly is mounted between a top-cover and a bottom-cover of a gearbox.
15. The medical device of claim 14 , wherein axes of the plurality of spur gears extend from the bottom-cover to the top-cover of the gearbox, and wherein the shaft of the electric motor lies horizontally between the covers.
16. The medical device of claim 14 , wherein the top-cover and the bottom-cover are detachably connected.
17. The medical device of claim 14 , wherein the top-cover and the bottom-cover are detachably connected by screws.
18. The medical device of claim 1 , wherein the worm wheel has 22 teeth and reduces motor speed by a ratio of 22:1.
19. The medical device of claim 2 , wherein the multistage speed-reducing unit has three meshing gear pairs.
20. A hand-held medical device comprising:
a housing with a cassette compartment;
an exchangeable test tape cassette received in the cassette compartment, the test tape cassette comprising a test tape having test elements thereupon that can be provided for successive use and at least one tape spool connected to the test tape; and
a drive assembly comprising an electric motor and a gear arrangement adapted for rotating the tape spool, wherein the gear arrangement has a worm drive in which a worm meshes with a worm wheel and a multistage speed-reducing unit comprising a plurality of spur gears arranged between the worm wheel and an output gear directly coupled to the tape spool, wherein the plurality of spur gears are arranged in a non-linear configuration so that centers of the spur gears span a polygon selected from the group consisting of a triangle and a quadrangle, and wherein a rotational axis of the electric motor is skewed or perpendicular to rotational axes of the plurality of spur gears.
21. The medical device of claim 20 , wherein each of the plurality of spur gears has at least about 10 teeth, wherein the output gear has about 60 teeth, and wherein the worm is directly mounted on a motor shaft of the electric motor.
22. The medical device of claim 20 , wherein the worm wheel has 22 teeth and reduces motor speed by a ratio of 22:1.
23. The medical device of claim 20 , wherein the multistage speed-reducing unit has three meshing gear pairs.