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Motor Bearing
Published in Wei Tong, Mechanical Design and Manufacturing of Electric Motors, 2022
Slewing bearings can be produced in a variety of constructions and shapes, in terms of row number (e.g., single-, double-, or multi-row), type of rolling elements (e.g., balls, taped rollers, or cylindrical rollers), roller arrangement, and raceway geometry. Figure 6.15 shows a single-row ball slewing bearing with a simple structure. Like regular ball bearings, this type of bearing consists of an inner ring, an outer ring, a number of spacers and balls, and seals (now shown). The mounting holes are provided at both inner and outer rings.
Modelling and calibration of a five link elastic boom of a mobile concrete pump
Published in Mathematical and Computer Modelling of Dynamical Systems, 2023
M. Meiringer, A. Kugi, W. Kemmetmüller
A sketch of the boom under consideration is depicted in Figure 2. It consists of 5 individual hydraulically actuated rotational joints, where each joint is followed by an elastic link. The first joint (slewing gear) allows a rotation of the boom around the vertical -axis, oriented with the negative direction of gravity. The remaining joints 2 to 5 form a planar manipulator in the -plane. Joint 2 and 3 are actuated using linear hydraulic actuators together with special linkages that transform the linear motion of the actuators to a rotation. Joint 4 and 5 are directly actuated by rotational hydraulic motors. The end effector (i.e. the concrete distribution hose) is attached to the end of link 5. In this work, this hose is not further considered and thus, the end of link 5 is referred to as the end effector. It is obvious that if the task space is given by the 3-dimensional position of the end effector, the manipulator comprises a redundant kinematics of order 2, see, e.g. [13].
First Bio-Based Composite Movable Bicycle Bridge
Published in Structural Engineering International, 2021
Wouter Claassen, Georgios Zarifis
Another important design aspect is fatigue damage to the movable part caused by the opening cycles of the bridge. The point of interest for the fatigue damage is the connection of the bridge to the slewing ring on the rotation axis of the bridge at axis 2, see Fig. 6. This connection has been performed using an intermediate wedged-shaped plate between the bridge and the slewing ring, see Ref. [3]. The connection of the wedged plate to the transverse webs of the bridge is performed using stiffened angle cleats and bolts, as can be seen in Fig. 7. Fatigue appears to be critical and is present in the form of bearing stress at the laminate around the bolts. The actual fatigue stress intervals depend on the time/phase difference of the uplift mechanisms located at the two ends (axis 1 and axis 3, see Fig. 6) of the bridge during opening and closing but also on the deflection of the bridge in the open position, which is influenced by temperature and creep evolution in time, see Ref. [3].
Vision-based load sway monitoring to improve crane safety in blind lifts
Published in Journal of Structural Integrity and Maintenance, 2018
Yihai Fang, Jingdao Chen, Yong K. Cho, Kinam Kim, Sijie Zhang, Esau Perez
Load sway is a typical phenomenon in crane lifting operations. It’s usually incurred by strong wind or inertia due to crane maneuver. Load sway does not only compromise lift efficiency but also pose significant threat to lift safety such as colliding with surrounding objects or creating undesired lateral loading to the boom. When a sway occurs, experienced operators manage to mitigate the sway by timing the crane movement and carefully driving into the sway. However, such a maneuver is extremely difficult when the operators don’t have a direct line-of-sight to the load in blind lift scenarios. Despite much research focusing on capturing the motions of crane parts (e.g., boom lifting and slewing), few successfully tackled the challenge in effective monitoring and warning of load sway.