Pneumatic couplings with constant twist angle control are suitable for tuning mechanical systems where the load torque is proportional to the square of shaft speed. This is typical mostly for drives of ships used in water transportation. In given conditions, the coupling maintains the ratio of natural torsional frequency to rotational speed of the mechanical system at a constant value. With proper setting of constant twist angle, resonance with harmonic excitation components in a specific range of operating speed can be avoided. The goal of this article is to present a design of a newly built prototype of coupling with mechanical constant twist angle regulator. During further research, it is planned to be tested in laboratory conditions.

Presently, mechanical system vibroisolation is becoming increasingly important. One of the new approaches is semi-active vibroisolation using elements capable of changing a selected mechanical property. These include, among others, pneumatic flexible shaft couplings capable of changing torsional stiffness during operation. The main goal of the article is to examine the potential advantages of a newly patented pneumatic coupling over a current type with the same pneumatic element arrangement. For comparison, parameters determinable from static load characteristics were selected. These parameters are maximum twist angle and torque, average torsional stiffness, and the percentage of torque transmitted by the bellows rubber shell. In all cases, the new coupling had better properties. Since the prototype of the new coupling has not yet been produced, its parameters were determined from its mathematical-physical model. The article contains a full procedure to obtain the static load characteristic of a new coupling type, beginning with the determination of air bellows force/height and volume/height characteristics, then optimum sizes of coupling with regards to the operating range of elements, the dependency of element height on the coupling’s twist angle, and finally the computation of the static load characteristic considering isothermal gas compression. The presented procedure can be applied to any pneumatic bellows where the force/height characteristics of different pressures are given.

The industries of shipping, shipbuilding and port operations are among those in which mechanical drives with piston machines are widely used. The wide use of piston machines is the result of many years of experience and many years of development and modernization of piston machines. Usually, they operate as mechanical drives with constant operating speeds, with the exception of drives with combustion engines, which operate in a wider range of operating speeds. The limiting condition of innovation of mechanical drives with piston machines, resulting from the nature of the piston machine operation, is the torsional oscillation. The effort to decrease an energy demand of mechanical drives requires the application of non-traditional working modes, which can be considered as a deactivation of the cylinders of piston machine or an expansion of the working speed range. One of the possibilities of eliminating these limiting factors is an application of a pneumatic tuner in mechanical drives, which, in contrast to traditional solutions, has a wide range of torsional stiffness that can be smoothly changed. During experimental measurements in the resonance area, at the operating speed of 700 rpm after torsional stiffness change, a torsional vibration value of 15 Nm decreased to 5 Nm.

Streszczenie: Obecnie, w przemyśle samochodowym, szeroko i wnikliwie rozważa się problem wzbudzania oraz eliminacji drgań w pojazdach

This paper is focused on the suitability of the selection of the parameters of the supporting structure of the bridge crane for the needs of cross-section optimization. The cross section of the beam is analysed in terms of its rigidity and dimensions with respect to the span of the crane. When optimizing to reduce overall weight, recommendations are given to address the issue of cross-sectional stability. An iterative procedure for the design of the cross-section of the beam at the specified load capacity of the crane and its span is proposed. In the article, only a theoretical analysis of the issue for the selection of suitable cross-section parameters of the crane girder for optimization needs is made, with the indication of another possible procedure for the optimization process itself aimed at minimizing the weight of the bridge crane girder.

Streszczenie: Badania, rozwój oraz produkcja rodków transportu charakteryzuj cych si zero emisyjno ci maj wysoki priorytet w ekonomii Unii Europejskiej.Nap dy hybrydowe s alternatywnymi rodzajami nap du pojazdów

Streszczenie: Od początku produkcji maszyn z elementami obrotowymi, producenci spotykali się z takimi problemami jak wyważenie, oscylacje oraz drgania.Te ostatnio wspomniane czynniki często powodowały uszkodzenia elementów oraz całych urządzeń.Celem projektantów stało się eliminowanie