Special tractor driving wheels with two modification of spikes inclination angle

R. Abrahám¹*, R. Majdan¹ and R. Drlička²

¹Department of handling and transport machinery, Faculty of Engineering, Slovak University of Agriculture in Nitra, Tr.A. Hlinku 2, SK949 76 Nitra, Slovak Republic
²Department of Quality and Engineering Technologies, Faculty of Engineering, Slovak University of Agriculture in Nitra, Tr.A. Hlinku 2, SK949 76 Nitra, Slovak
*Correspondence: rudolf.abraham@uniag.sk

Abstract:

The paper presents a research on an improvement of tractor drawbar properties using special driving wheels. Two modifications of the special driving wheels were designed and tested under field conditions. The results were compared with standard tyres. The special driving wheels consists of the tyres with a modified tyre-tread pattern and equips with the spike segments. The special driving wheels allow to activate or deactivate the spike segments to improve a drawbar pull at worse adhesive conditions of the ground or transport on roads with standard tyres. The first modification activates all 8 spike segments at spike inclination angle 90° and the second one 4 at angle 90°and 4 at 30°. The measurements were realised in October 2017 in an area of the Slovak Agricultural Museum in Nitra. The drawbar properties of the special driving wheels were evaluated based on drawbar pull of the test tractor Mini 070 type connected with a load tractor MT8-065 type. Using the test tractor in 1st and 2nd gear, the measurements were realized at 100% wheels slip and repeated 4 times. The results show the statistically significant differences in the drawbar pull of the test tractor with different driving wheels on a grass plot. The highest increase in drawbar pull reached the value 25.56% (2nd gear) and 19.98% (1st gear) in case of the special driving wheels with 4 spike segments at 90° and 4 at 30°. In case of the special driving wheels with 8 spike segments at 90°, increase in the drawbar pull reached the value 10.09% (1st gear) and 15.21% (2nd gear) in comparation with the standard tyres.

Key words:

drawbar pull, force sensor, tyres, wheels slip

Verification of mathematical model of pressure distribution in artificial knee joint

V. Novák¹, D. Novák² J. Volf¹ and V. Ryzhenko¹*

¹University of Life Sciences Prague, Faculty of Engineering, Kamýcká 129, CZ165 21 Prague, Czech Republic
²Matej Bel University, Faculty of Natural Sciences, Department of Technology, Tajovského 40, SK974 01 Banská Bystrica, Slovakia
*Correspondence: volf@tf.czu.cz

Abstract:

The paper deals with pressure distribution measurement in knee arthroplasty, which is an artificial replacement of human knee joint. The scope of the article is to verify the accuracy of a mathematical model by real measurements. The calculated pressure values basing on the mathematical model are compared with actually measured pressure values in the contact area of the joint. Hereby maximal load the in the contact area, the distribution of the pressure and any potentially dangerous pressure deviations during the walk cycle are checked. To enable accurate pressure distribution measurement without interfering into human’s body, a sophisticated measuring setup was created: the contact area of the joint was equipped with several pressure sensors and a machine simulating the human walk cycle was used. The measured pressure data are finally compared with those from the mathematical model and with the strength limit of the used material, to verify the accuracy of the mathematical model experimentally.

Key words: