The use of surface analysis to investigate brake elements shows how a pair in contact works and wears out during regular operation. The main purpose of this paper is to describe the asperities from initial state to a moment when further use of the drum and shoe is not possible. Between exchange of vital brake elements a truck with total mass exceeding 3.5 tons can cover as many as 300 000 kilometres. Use of brakes during the first 1000 kilometres after maintenance should be rather gentle with possibly intensive use of engine brake installed in the truck itself, because if this rule is not adhered to it may lead to a significant decrease of the braking force and on the surface of the pair in contact a layer will appear that is not possible to wear off and that will make it impossible to stop a truck using brakes. In that condition the shoe should be immediately replaced and the drum should be remachined (by turning) to a repair dimension. In the paper the condition and analysis of a surface after different course of exploitation was presented.
The antilock brake system (ABS) was developed, which coordinates actions of auxiliary and working braking systems of a trolleybus. A trolleybus type 321 "Belkommunmash", equipped with the proposed ABS was tested in road conditions. The results of tests confirmed compliance of the trolleybus with requirements of the rules UN EEC No 13. Decrease in slippage of the driving wheels, improved stability, roadability and traffic safety of the trolleybus was noted.
The iron ore mine owned by the state concern of Luossavaara – Kiirunavaara AB-LKAB state concern has several mining skip shaft hoists for drawing iron ore. Despite using modern systems to secure the travel of these hoists in line with the Swedish regulations, units intended for the emergency breaking of vessels must be used in the so-called free travel paths in the tower and in the shaft sump. The paper discusses the main requirements that, in accordance with the Swedish regulations as regards the operational use of mining shaft hoists, must be met by devices of this type and a solution was proposed for a structure design of the braking unit for the mining shaft hoist installed in the B-1 shaft in the Kiruna mine. The frictional braking system in the form of moving bumping beams was decided to be used in the said hoist, developed in the Cable Transport Department in the University of Science and Technology in Krakow. The action of moving bumping beams consists in these beams, placed at the beginning of free travel paths, not only braking the rushing hoist vessels but also (with the integrated units for vessel capture) performing the function of grips. They secure the vessels against falling down into the shaft after the finished braking process. The advantage of such a solution is that the structural elements: the guiding shank of the tower, the head of the vessel and the bumping beams, transfer many times lower values of dynamic forces at the time of the strike of the vessel against the moving bumping beams when compared with dynamic forces arising at the time of the hit of the vessel against the fixed bumping beams. In the process of designing moving bumping beams, braking simulation is an important stage conducted with a computer program developed in KTL AGH. This program enables the modelling of load-bearing and balance ropes as flexible elements with elastic and suppressing properties. The results of these simulations, especially in the scope of the achieved braking deceleration of the vessels, the values of braking distances and forces in the load-bearing ropes are crucial in confirming the correctness of the assumed concept of the emergency braking system. The braking units in the form of moving bumping beams have been executed by the Polish company Coal-Bud Sp. z o.o. and are now being integrated in the tower and in the shaft sump of the B-1 shaft of the Kiruna mine in Sweden.