Diagnostic tape cassette

1. A diagnostic tape cassette for use with a blood glucose testing device, comprising: an analytical test tape, a supply spool and a take-up spool wherein unused portions of the analytical test tape are provided on the supply spool and unwound for use and wherein used portions of the analytical test tape are wound up onto the take-up spool that rotates around a spool axis, a housing for the spools and a rotational lock for the take-up spool configured to prevent inadvertent unwinding of test tape at least from the take-up spool, wherein the rotational lock comprises a friction element attached to a housing surface which is brought into frictional engagement with a facing contact surface of the take-up spool in response to the take-up spool being moved axially along the spool axis out of a release position to a frictionally locked position, wherein in the frictionally locked position a return spring between the housing and the take-up spool forces the facing contact surface and the friction element against one another.

2. The tape cassette according to claim 1 , further comprising a friction ring arranged coaxially with respect to the take-up spool and the friction element is located on the friction ring.

3. The tape cassette according to claim 1 , wherein the friction element comprises an elastomer material.

4. The tape cassette according to claim 1 , wherein the friction element is located on the housing surface.

5. The tape cassette according to claim 1 , wherein the housing surface comprises a ring flange defining an opening having a rim, and wherein the friction element is arranged circumferentially on the ring flange in the area of the rim of the opening.

6. The tape cassette according to claim 1 , further comprising a cylindrical spool body around which the test tape can be wound, the cylindrical spool body including a collar and the facing contact surface is located on the collar.

7. The tape cassette according to claim 1 , wherein the take-up spool is braced against the housing in the direction of the spool axis by the return spring such that the frictional engagement occurs under the restoring force of the return spring.

8. A test system comprising a test device and a diagnostic tape cassette inserted therein, the tape cassette comprising: an analytical test tape, a supply spool and a take-up spool wherein unused portions of the analytical test tape are provided on the supply spool and unwound for use and wherein used portions of the analytical test tape are wound up onto the take-up spool which rotates around a spool axis, a housing for the spools and a rotational lock for the take-up spool configured to prevent inadvertent unwinding of test tape, the rotational lock comprising a design selected from the group of lock designs consisting of (i) locking teeth disposed on opposing surfaces of the housing and the take-up spool, said teeth being shifted by an axial movement of the take-up spool between a mutually engaged position and a release position, wherein in the mutually engaged position the locking teeth of the take-up spool engage the locking teeth of the housing and in the release position the locking teeth of the take-up spool are axially spaced from the locking teeth of the housing, (ii) a friction element attached to a housing surface which is brought into frictional engagement with a facing contact surface of the take-up spool in response to the take-up spool being moved axially along the spool axis out of a release position to a frictionally locked position, wherein in the frictionally locked position a return spring between the housing and the take-up spool forces the facing contact surface and the friction element against one another, and (iii) a locking spring attached to the housing and axially pretensioned against the take-up spool along the spool axis, and the locking spring includes at least one spring latch that meshes with free-wheel teeth arranged on the front of the take-up spool to prevent against unwinding of a tape loop.

9. The test system according to claim 8 , wherein a drive spindle of the test device engages in the take-up spool when the tape cassette is inserted into the test device.

10. The test system according to claim 9 , wherein when the take-up spool is moved axially against the return spring, the drive spindle lifts out the locking teeth or releases the frictional connection of the friction element into the release position.

11. The test system according to claim 9 , wherein the drive spindle can be adjusted by a spring in the direction of an axis of rotation and engages in the take-up spool under spring displacement.

12. The test system according to claim 9 , wherein the drive spindle in a driver bore of the take-up spool transfers a rotary movement of at least one driver.

13. The test system according to claim 8 , further comprising a friction ring on the housing surface arranged coaxially with respect to the take-up spool and the friction element is located on the friction ring.

14. The test system according to claim 13 , wherein the friction element comprises an elastomer material on the housing surface.

15. The test system according to claim 8 , wherein the friction element is located on the housing surface.

16. The test system according to claim 8 , wherein the housing surface comprises a ring flange defining an opening having a rim, and wherein the friction element is arranged circumferentially on the ring flange in the area of the rim of the opening.

17. The test system according to claim 8 , further comprising a cylindrical spool body around which the test tape can be wound, the cylindrical spool body including a collar and the facing contact surface is located on the collar.

18. The test system according to claim 8 , wherein the take-up spool is braced against the housing in the direction of the spool axis by the return spring such that the frictional engagement occurs under the restoring force of the return spring.