Synthesis of Stationary Cams

1999 ◽  
Vol 121 (1) ◽  
pp. 169-172 ◽  
Author(s):  
L.-I. Wu ◽  
P.-H. Fang
Keyword(s):  
Design Process ◽  
Transition Curve ◽  
Gradual Change ◽  
Tool Magazine ◽  
Cam Design ◽  
Circular Arcs ◽  
Automatic Tool ◽  
Pitch Curve ◽  
Straight Lines ◽  
Transition Curves

This paper presents a method for designing stationary cams with constant speed roller followers. A stationary cam is immovable, but it guides its follower to produce a desired motion with the follower being driven by other links. In order to avoid infinite jerk of the follower motion, the pitch curve of a stationary cam should consist of pieces of transition curve, which provide gradual change in curvature and are interposed between straight lines and circular arcs. The general parametric equations of transition curves are derived and the cam design process is demonstrated. This method is applicable for designing the guideways of tool magazine in automatic tool-changing system of the machine center.

Design of backlash-free straight-curved guide devices

2014 ◽  
Vol 228 (15) ◽  
pp. 2833-2843
Author(s):  
Long-Iong Wu ◽  
Kuan-Lwun Shu
Keyword(s):  
Common Point ◽  
Transition Curve ◽  
Circular Arc ◽  
Contact Points ◽  
Straight Line ◽  
Pitch Curve ◽  
Slider Motion ◽  
Guide Device

This article presents a method for designing a planar guide device that can guide sliders to move along a straight-curved rail and can eliminate the backlash between the slider and the rail throughout the whole range of the slider travel. The guide device has many sliders and each slider has three rollers that can separately roll on both sides of the rail. The straight-curved rail is composed of straight sections, connection sections, and circular-arc sections. For each slider, the three normal lines through the contact points between the rollers and the rail must always intersect at a common point, which is an instant center. Using this as a basis, the side profiles of the straight-curved rail can be determined. To avoid infinite jerk of the slider motion, the pitch curve of the connection section should consist of a transition curve, which is interposed between the straight line and the circular arc.

Spline Based Design of Cam Contours for Improved Dynamic Performance

1993 ◽  
Author(s):  
Holly K. Ault ◽  
James C. Wilkinson
Keyword(s):  
Dynamic Performance ◽  
Integrated Design ◽  
Polynomial Functions ◽  
Piecewise Polynomial ◽  
Cam Design ◽  
Piecewise Polynomial Functions ◽  
Cam Follower ◽  
Cam Profile ◽  
Pitch Curve ◽  
Design And Manufacture

Abstract A method for the integrated design and manufacture of radial plate cams is discussed. Currently, a cam-follower system is designed by specifying constraints on the motion of the follower. The physical cam contour or cam pitch curve are not mathematically defined. The cam is manufactured from the discretized follower motion program. A new method for cam design is proposed which will produce a smooth, mathematically defined cam pitch curve while maintaining the proper constraints on the follower motion. Piecewise polynomial functions in the form of rational and/or non-rational splines may be used. Cams will be manufactured using smoothed profiles and tested for improved dynamic performance. The results of initial investigations of cam profile design for this research are presented.

A Methodology for the Configuration Synthesis of Machining Centers With Automatic Tool Changer

1996 ◽  
Author(s):  
Hong-Sen Yan ◽  
Fu-Chen Chen
Keyword(s):  
Design Methodology ◽  
Systematic Approach ◽  
Coordinate Systems ◽  
Linear Type ◽  
Open Type ◽  
Tool Magazine ◽  
Automatic Tool Changer ◽  
Configuration Synthesis ◽  
Automatic Tool ◽  
Motion Characteristics

Abstract The purpose of this paper is to present a design methodology for the configuration synthesis of machining centers with automatic tool changer to meet the required topology and motion characteristics. According to the concept of coordinate systems, graph theory, generalization, specialization, and motion synthesis, this design methodology is proposed and computerized, and the machining centers with automatic tool changer up to eight links are synthesized. As the result, for the machining centers with drum type tool magazine, the numbers of configurations of machining centers with 6, 7, and 8 links are 2, 13, and 20, respectively. And, for the machining centers with linear type tool magazine, the numbers of configurations of machining centers with 5, 6, 7, and 8 links are 1, 5, 20, and 60, respectively. Furthermore, this work provides a systematic approach for synthesizing spatial open-type mechanisms with topology and motion requirements.

On the Planning and Construction of Railway Curved Track

2021 ◽  
Vol 13 (2) ◽  
Author(s):  
Sono Bhardawaj ◽  
Rakesh Chandmal Sharma ◽  
Sunil Kumar Sharma ◽  
Neeraj Sharma
Keyword(s):  
High Speed ◽  
Time Derivative ◽  
Railway Track ◽  
Lateral Acceleration ◽  
Transition Curve ◽  
Railway Vehicle ◽  
Geometric Conditions ◽  
Curve Track ◽  
Curved Track ◽  
Transition Curves

Increasing demand for railway vehicle speed has pushed the railway track designers to develop high-quality track. An important measure of track quality is the character of the transition curve track connecting different intersecting straight tracks. A good transition curve track must be able to negotiate the intermittent stresses and dynamic effects caused by changes in lateral acceleration at high speed. This paper presents the constructional methods for planning transition curves considering the dynamics of movement. These methods consider the non-compensated lateral acceleration, deviation in lateral acceleration and its higher time derivatives. This paper discusses the laying methods of circular, vertical and transition curves. Key aspects in laying a curved track e.g. widening of gauge on curves are discussed in this paper. This paper also suggests a transition curve which is effective not only from a dynamic point of view considering lateral acceleration and its higher time derivative but also consider the geometric conditions along with the required deflection angle.

scholarly journals Mesomorphism Dependence on Cis-Trans Configuration and Varying Terminal/Lateral Group

2016 ◽  
Vol 65 ◽  
pp. 71-79
Author(s):  
G.N. Bhola ◽  
Umed C. Bhoya
Keyword(s):  
Thermal Stability ◽  
Homologous Series ◽  
Vinyl Ester ◽  
Molecular Structures ◽  
Transition Curve ◽  
Group Efficiency ◽  
Lateral Group ◽  
Normal Manner ◽  
Thermotropic Liquid Crystals ◽  
Transition Curves

A chalconyl trans vinyl ester homologous series of thermotropic liquid crystals RO-C6H4-CH=CH-COO-C6H4-CH=CH-CO-C6H3(OCH3)2meta-para is synthesized and studied with a view to understand and establish the relation between molecular structure and mesomorphism or mesomorphic behaviors. Novel homologous series consists of thirteen homologues (C1to C18). First five (C1to C5) homologues are nonmesogenic. Rest of the homologues (C6to C18) homologues is mesogenic. Monotropically smectogenic character appears from C6to C10homologue and C12to C18homologues are enantiotropically smectogenic. Nematogenic property is totally absent throughout a series. Textures of smectic phase are of the type smectic A or C. Transition curves of a phase diagram behaved in normal manner. Analytical, spectral and thermal data supports the molecular structures of homologues. Odd-even effect is observed for Sm-I/I-Sm transition curve. Thermal stability for smectic is 93.7 °C and the mesomorphic phase lengths from enantiotropic homologues for smectic from minimum to maximum is 6.0 °C to 28.0 °C at the C12and C18homologue respectively. Series is smectogenic without exhibition of nematic property. The group efficiency order on the basis of thermal stability is derived; from comparative study of present series and analogous series.

Optimal Design of Computerized Flat Knitting Machine Cam Curves Based on UG and ANSYS/LS-DYNA

2014 ◽  
Vol 529 ◽  
pp. 410-414
Author(s):  
Cang Zhao ◽  
Guang Li Song ◽  
Lei Xu
Keyword(s):  
Finite Element ◽  
Optimal Design ◽  
Dynamic Analysis ◽  
Maximum Stress ◽  
Analysis Software ◽  
Forming Process ◽  
Polynomial Curve ◽  
Circular Arcs ◽  
Design Software ◽  
Straight Lines

By combining the industrial design software UG and finite element dynamic analysis software ANSYS/LS-DYNA, the paper respectively designs the non-linear knitting cams with polynomial curves, and simulates the loop-forming process in the interaction between the cams and needles. Based on comparative analyses, it’s thereby concluded that the polynomial curve has the best performance and is significantly superior to the cam curve composed of straight-lines and circular-arcs; the elements with higher stresses are located above the butt of needle jack and the joint of the jack and latch needle; and the polynomial curve is effective in lowering the maximum stress of the needle.

An Analysis of the Shape and Propagation of Waves on the Flagellum of Crithidia Oncopelti

1979 ◽  
Vol 80 (1) ◽  
pp. 299-315
Author(s):  
D. N. JOHNSTON ◽  
N. R. SILVESTER ◽  
M. E. J. HOLWILL
Keyword(s):  
Back Projection ◽  
Active Process ◽  
Automatic Data ◽  
Circular Arcs ◽  
Fourier Series Method ◽  
Dark Ground ◽  
Propagation Of Waves ◽  
Straight Lines ◽  
Best Fit ◽  
Automatic Data Acquisition

Ciné micrographs were taken of the flagellated protozoan Crithidia oncopelti under dark-ground illumination. Coordinates of images of the flagella were obtained from the ciné frames by back-projection and automatic data acquisition. The flagellar waveforms of proximally directed waves were characterized using a Fourier-series method and compared by this means with a number of analytical curves. The shape of a wave remained constant as it was propagated and, of the curves suggested, a wave consisting of circular arcs connected by straight lines gave the best fit. The variation of bend curvature as bends moved along the flagellum was also found, for both proximally and distally directed waves. The wavelengths and speeds of proximally directed waves increased linearly with distance as they approached the base of the flagellum, while in distally directed bends the curvature remained constant but the velocity increased as bends moved away from the base. Causes of the above behaviour are discussed and it is concluded from the variation of curvature with time for proximally directed flagellar waves that unbending must be an active process.

scholarly journals Linkage and Cam Design with MechDev Based on Non-Uniform Rational B-Splines

Machines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 5 ◽  
Author(s):  
Mario Müller ◽  
Mathias Hüsing ◽  
Agnes Beckermann ◽  
Burkhard Corves
Keyword(s):  
Mechanism Design ◽  
Design Process ◽  
Input Function ◽  
Use Case ◽  
Servo Drive ◽  
B Splines ◽  
Cam Mechanism ◽  
Software Products ◽  
Cam Design ◽  
Transmission Angle

Several software products exist in order to support engineers during the mechanism design process. The software “Mechanism Developer” (abbr. MechDev) is one of these products. MechDev provides many functionalities concerning the kinematic and kinetostatic analysis of mechanisms based on revolute, prismatic as well as cam joints. This paper will introduce the software MechDev and will outline these functionalities. Furthermore, it will name the advantages of MechDev compared to other software products. In order to give an impression of the functionality of the software, this paper also includes a special use case. This use case describes a cam mechanism with a prismatic roller-follower. In order to optimize the transmission angle of the cam mechanism, the cam is actuated by a servo drive. To mathematically model the angular input of the servo drive, Non-Uniform Rational B-Splines (NURBS) are described and applied. Thus, a nearly arbitrary input function can be described by few parameters.

Fitting multispiral transition curve joining two straight lines

2012 ◽  
Vol 44 (6) ◽  
pp. 591-596 ◽  
Author(s):  
Rushan Ziatdinov ◽  
Norimasa Yoshida ◽  
Tae-wan Kim
Keyword(s):  
Transition Curve ◽  
Straight Lines
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