Patent ID: 8618948

Claim:
An injection device for automatically injecting a medicament into a human, the injection device comprising an injection unit, a measurement unit, a first memory, a second memory, a switching unit, an evaluation unit, a comparator unit, and an occlusion alarm unit, wherein: the injection unit is coupleable to the human to deliver automatically a plurality of injections of the medicament into the human, wherein the plurality of injections are each delivered according to an injection time period; the measurement unit is mechanically coupled to the injection unit and measures an injection force, at the injection time period, for each of the plurality of injections; the first memory is electrically coupled to the measurement unit and stores a value of the injection force for each of the plurality of injections measured by the measurement unit, thereby forming a series of force measurements; the switching unit is electrically coupled to the first memory and the second memory such that the switching unit reads the series of force measurements from the first memory, generates a plurality of evaluation forces based on an evaluation time period, and writes the plurality of evaluation forces to the second memory; the second memory also stores gradient values of force increase values predetermined statically by experiment as a function over increasing observation periods and which form first, second and third gradient value parts, where the first gradient value part defines a first area in which an occlusion is present, where the second gradient value part defines a second area in which no occlusion is present, and the third gradient value part defines a third area which lies between the first and second areas and in which it is not possible to conclude unambiguously that there is an occlusion; the evaluation unit is electrically coupled to the second memory and determines whether to provide an occlusion alarm signal based on an evaluation of the plurality of evaluation forces from the comparator unit which concludes that there is an occlusion; the comparator unit, which is electrically coupled to and interacts with the evaluation unit, is configured to compare the plurality of evaluation forces with the stored gradient values of force increase values predetermined statically by experiment to conclude one of: that there is an occlusion if the evaluation forces are in the first area defined by the first gradient value part, that there is no occlusion if the evaluation forces are in the second area defined by the second gradient value part, and that there is no determinable occlusion if the evaluation forces are in the third area defined by the third gradient value part; and the occlusion alarm unit which receives the occlusion alarm signal such that the occlusion alarm unit provides an injection occlusion alarm based on the occlusion alarm signal.