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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A Computational Iteration Method to Analyze Mechanics of Timing Belt Systems with Non-Circular Pulleys

Tan, Li 10 September 2018 (has links)
Timing belt systems, usually consisting of a toothed belt and multiple pulleys, are used in many mechanical devices, especially in the internal combustion engine to synchronize the rotation of the crankshafts and the camshafts. When the system operates, the belt teeth will be transmitted by the pulley teeth meshed with them. Timing belt drives can make sure that the engine' s valves open and close properly due to their precise transmission ratio. In this thesis, a quasi-static computational model is developed to calculate the belt load distributions and the torques around pulleys for different timing belt systems. The simplest system is a two-pulley system with one oval pulley and one circular pulley. This computational model is then extended to a two-pulley system with one special-shaped pulley and finally generalized to determine the load conditions for a multi-pulley system with multiple special-shaped pulleys. Belt tooth deflections, tooth loads, belt tension distributions, friction forces, and the effect of friction hysteresis have been taken into consideration. Results of these quantities are solved by a nested numerical iteration method. Periodic torques generated by the varied radius of noncircular pulley are calculated by this computational model to cancel the undesired external cyclic torque, which will increase the life of timing belts. / Master of Science / Timing belt systems, usually consisting of a toothed belt and multiple pulleys, are used in many mechanical devices, especially in the internal combustion engine to synchronize the rotation of the crankshafts and the camshafts. When the system operates, the belt teeth will be transmitted by the pulley teeth meshed with them. Timing belt drives can make sure that the engines valves open and close properly due to their precise transmission ratio. In this thesis, a quasi-static computational model is developed to calculate the belt load distributions and the torques around pulleys for different timing belt systems. The simplest system is a two-pulley system with one oval pulley and one circular pulley. This computational model is then extended to a two-pulley system with one special-shaped pulley and finally generalized to determine the load conditions for a multi-pulley system with multiple special-shaped pulleys. Belt tooth deflections, tooth loads, belt tension distributions, friction forces, and the effect of friction hysteresis have been taken into consideration. Results of these quantities are solved by a nested numerical iteration method. Periodic torques generated by the varied radius of noncircular pulley are calculated by this computational model to cancel the undesired external cyclic torque, which will increase the life of timing belts.
2

Kalibrace geometrie vln vytvořených na matrici(lisovnici) z plechu / Sizing of the waves geometrical parameters fabricated on the sheet metal die

Stupárek, Daniel January 2010 (has links)
This thesis approaches the problem of the return of the original geometric shape of the wave which is created on die panels. Die is used as a structural feature of the fiber-cement roofing material in its shipment in the production line. Based on the study of the theory of cold formed sheet metal determine the actual status in the plant. The method of calibration was designed from the collected informations about the original manufacturer of sheet metal panels. Under this proposal and calculation of the required forming power for the recalibration wave in the factory device for the die calibration was designed and constructed. Equipment calibration was performed on two types of corrugated panels and the result fulfilled the theoretical assumptions. In conclusion is processed technological-economic evaluation and the accompanying drawings.
3

Modelování a experimentální ověření lanového skluzu / Modelling and experimental verification of zipline

Dobrovolný, Tomáš January 2019 (has links)
The diploma thesis deals with the numerical modeling of the zip-line and its experimental verification on a small scale. An experimental zip-line is identified and then the results are compared with the numerical model outputs. The goal is to validate abilities of the numerical model in the case of simulation of a zip-line.
4

Coupled belt-pulley mechanics in serpentine belt drives

Kong, Lingyuan 22 January 2004 (has links)
No description available.
5

Poranění šlachových poutek jako jeden z nejčastějších úrazů ve sportovním lezení / Flexor tendon pulley lesion as a most frequent injury in sport climbing

Čížková, Michaela January 2014 (has links)
Title: Flexor tendon pulley lesion as a most frequent injury in sport climbing Specification of the problem: This thesis is focused on the most frequent injury of the hand in sport climbing. It describes the mechanism of the injury and possibilities of conservative and surgical treatment according to the given guidelines in dependence on its relevance. Objectives: The aim of this thesis is the literary review of accessible literary resources from the field of anatomy, kinesiology and biomechanics of the hand and flexor tendon pulley in connection with a sport activity. Furthermore it is aimed on an analysis why is the flexor tendon pulley injury the most frequent injury in sport climbing, and on methods how to treat this injury in the most effective way from the beginning till the return to the full performance based on therapeutic guidelines created by Dr. Schöffl nad Dr. Hochholzer. This thesis should serve as a therapeutic manual for the Czech sport climbers suffering from this type of injury, which is generally very often underestimated and not treated sufficiently. Methods: This diploma thesis has descriptively-analytical character and is structured as a literary review. Keywords: tendon pulley, hand, sport climbing, physiotherapy, conservative treatment
6

Pohon motokáry elektromotorem / Electric powered go-cart

Štol, Michal January 2012 (has links)
This thesis deals with rebuilding of combustion engine powered go-kart for rent to electric powered go-kart. Main goal of work is choose fitting electric engine and electric accessories for reliable working of electric go-kart, put the whole electric drive to rear construction of go-kart and check mechanical part of electric drive.
7

Lanový drapák / Grab Dredger

Kubánek, Jan January 2009 (has links)
When soluting the contruction of a grab dredger we will deal with suitable solution with reference to its using and capacity, possibilites of its setting in low temperatures and incidental aplication of the exchangeable abrasion - resistant mouldings. There will be made a calculation of forces taking effect on a grab dredger and a check calculation of the chosen structural parts.
8

Algometrická analýza vlivu zavřeného úchopu na měkké tkáně v oblasti ruky a předloktí. / Algometric analysis of influence of crimp grip on soft tissues of hand and forearm.

Vávrová, Hana January 2013 (has links)
Title: Algometric analysis of influence of crimp grip on soft tissues of hand and forearm. Objectives: The main aim of this thesis is comparison and evaluation of changes of nociceptors sensitivity treshold in chosen points of upper extremities area before and after defined strain using pressure algometer. Methods: Data for the experiment was obtained using pressure algometr. Pain threshold was measured in defined 42 points in the order given at each subject firstly before strain and again immediately after defined strain of upper extremities (one minute hangig by the both hands in crimp grip on a campus board in this way: 10 sec strain plus 10 sec break, all six times). Then were measured values statisticaly analysed. Sources for processing of theoretical part of this work were obtained from expert articles and literature which follow up the given task. Results: Statisticaly important results show, that decreasing of pain threshold (on average by 100 - 160 kPa) comes about in tissues of upper extremity immediately after its loading in crimp grip, which means increasing of nociceptors sensitivity. At the same time it has been proved that nociceptors sensitivity in the area of tendon pulleys correlates with frequency of their injury quoted in a literature (that is the highest sensitivity in the...
9

Design And Implementation Of A Two-axes Linear Positioning System For Rapid Prototyping Applications

Yazicioglu, Faruk 01 September 2007 (has links) (PDF)
In this study, a two axes linear positioning system for testing and applying different rapid prototyping techniques was designed and manufactured. A cable/ pulley mechanism is utilized in the system for transmitting motion from motors into linear motion. Use of a cable/ pulley mechanism overcomes the problems resulting from the utilization of conventional drive systems like ball screws and decreases the overall cost of the system. The carriage elements of both axes were designed and manufactured by using investment casting. The molds used in casting were also designed and manufactured within this study. The designed system is controlled by a servo motion control system composed of a motion controller, DC servo motors and linear encoders. All elements of the motion control system were selected, integrated and programmed within the scope of the study.
10

Konstrukční návrh 3-osého manipulátoru / Design of 3 axis manipulator

Štol, Michal January 2011 (has links)
This thesis deals with design of 3 axis manipulator which manipulate wit ball bearing and moulding of pulley. Moulding of pulley is product of injection press. Part of this work is also technical-economics valuation of manipulating possibilities with ball bearing and pulley and is determinate the most useful option. Next is work out a conception of conveyor for ball bearings and pulleys.

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