SIMULATION OF DOOR MOVEMENT WITH A CLOSING MECHANISM

The work objective is to determine the parameters of the closing mechanism that provide the specified characteristics of the door movement. Research method: computer simulation of the movement of a door with a lock mechanism as a multi-mass dynamic system, taking into account the mechanical characteristics and contact interaction of the lock mechanism. Research results and novelty. Computer dynamic models of a door with a door closer and a door with a spring have been developed. The moments of the door opening force, the closing time of the door, the angular velocity of the door at the time of impact with the frame are considered as the criteria for the quality of the door closing mechanism. Formulas are obtained that determine the permissible values of stiffness and deformation of the door closer spring according to the specified moments of the door opening force. The movement of doors with a door closer and with a spring is compared. The parameters of the closing mechanism providing the specified characteristics of the door movement of the considered example are determined. It is shown that with the same values of the opening force moments, the speed of impact with the frame in the case of the door closer is less than the door with a spring. Conclusions: The developed computer dynamic models of a door with a door closer and a door with a spring make it possible to determine the characteristics of the door movement taking into account the inertial and mechanical characteristics of the door closer and spring mechanisms. The permissible values of stiffness and deformation of the door closer spring can be determined by the specified moments of the door opening force in two positions. It is established that the forces of air resistance and friction in the hinges of the door cannot create the moment of resistance necessary for smooth closing of the door without a strong impact on the frame with a limited closing time. The quality criteria that minimize the closing time and the speed of impact of the door with the frame are contradictory. The choice of optimal parameters of the door closing mechanism is possible if one of the criteria is replaced by a restriction. The developed formulas and computer models are recommended for use in the design of devices that restrict the movement of doors.

Dynamics Modeling and Simulation of a Net Closing Mechanism for Tether-Net Capture

Tether-net is a promising active debris removal technique, and a closing mechanism can ensure the reliable wrapping of space debris by using tether-net. This study focuses on the dynamics model of the split closing mechanism and the sliding joint between thread and ring. First, a new kind of closing mechanism is proposed, which drives the closing thread to close the net mouth through the split masses, and the mass-spring-damper method is used to model tether-net. Thereafter, for the first time, the model of thread-ring sliding joint is proposed based on the mass-spring-damper method, which can be used to simulate the closing process of tether-net. Finally, one-edge closure experiment of the net is carried out and the experimental results are compared with the simulation results, and the closing process of the tether-net is simulated by using the thread-ring sliding joint. Results reveal that the thread-ring sliding joint can be used to simulate the relative slip between the thread and the ring, and the tether-net can wrap the target reliably in a short time by using the split closing system. The split closing mechanism can make it possible for the tether-net to close successfully, whether it starts to work before or after the net contacts with the target.

The impact of closing mechanism changes: evidence from the Shanghai stock market

PurposeThe purpose of this paper is to empirically examine the impact of closing mechanism changes on market quality, investor trading behavior and market manipulation in the Shanghai stock market.Design/methodology/approachA dummy variable is constructed indicating whether the closing mechanism is call auction or continuous auction. Market quality is measured from aspects of liquidity, volatility and price continuity; investor trading behavior is scaled by order timing and order aggressiveness, and a price deviation indicator is the proxy of manipulation. Using panel regression, this study examines the impact of closing mechanism changes based on intraday transaction data from the Shanghai stock market.FindingsThe conclusions are as follows: First, market quality improves after the closing mechanism is reformed in terms of liquidity, volatility and price continuity. Second, order strategy changes significantly in the closing call market, and investors trade more aggressively in the continuous trading period before closing. Third, the closing call mechanism restrains the closing price manipulation and thus prompts an efficient closing price.Originality/valueThis paper examines the policy effects of closing mechanism changes from aspects of market quality, trading behavior and price manipulation, providing pieces of evidence for trading mechanism design and market supervision in emerging markets.

Modeling and robotic handling of a snap-fitting box buckle

Modeling and robotic handling of a plastic box buckle is discussed in this paper. The closing mechanism of the box buckle is simulated to determine the characteristic of the nonlinear load-deflection curve. An intelligent end-effector was designed and manufactured to handle the assembly with a robot. The closing force is measured by a built-in load cell and its values are processed by a micro-controller. The intelligent end-effector can be used in a robotic system, which deals with different snap-fit applications.