Framställning av fixtur för ISO-testning av kryckkäppar
Introduction: Dolomite AB was in need of a dummy arm for crutch testing, to complement their existing test capabilities. Background: A large number of people need crutches on a daily basis. For them it is essential that their crutches do not fail. ISO (the International Organization for Standardization) conducts ongoing work to guarantee the durability and function of e.g. crutches. ISO has recently adopted a new standard for testing if elbow crutches. This has already met resistance, it has been claimed that the tests in it should include loading of the crutch in the frontal plane. Aim: To enable Dolomite to test elbow crutches in accordance with guidelines in ISO/FDIS 11334-1. And examine the magnitude of loads on a crutch in the horizontal- sagittal- and frontal plane. This to see if loading of the crutch in the fontal plane should be included in a new ISO-test. Goal: To fabricate a dummy arm for testing of elbow crutches. To gain knowledge of the magnitude of the load a crutch is subject to in the horizontal-, sagittal-, and frontal plane. Method: A dummy arm was made using methods and tools described in DPD (dynamic product development), and conventional fabrication methods. A test equipment was made, which registered the loads on a crutch, in three directions. Eleven persons, constituted the test group, one was excluded. Result: A fully functional dummy arm was manufactured. The average maximum load for the ten test subjects was: 33 kilos downwards, 12 kilos backwards and 2 kilos side wards. Discussion: The choice of materials was influenced by the strength demands, ease of manipulation, access and price. Dummy arm design was mostly a question of durability and function. The test group was made up of persons available when the test was done The crutch loading test indicates that the forces applied to a crutch In the frontal plane are small, compared to forces in the horizontal- and sagittal plane, almost negligible. Conclusion: A fully functional dummy arm was fabricated, no need for a new ISO-test for standard crutches was identified.