Design of Drag-Link Mechanisms With Minimax Transmission Angle Deviation

1983 ◽  
Vol 105 (4) ◽  
pp. 686-690 ◽  
Author(s):  
L.-W. Tsai
Keyword(s):  
Optimum Design ◽  
Design Criterion ◽  
Parameter Design ◽  
Cubic Equation ◽  
Design Charts ◽  
Link Mechanism ◽  
Transmission Angle ◽  
Angle Deviation ◽  
Drag Link ◽  
Maximum Transmission

In this paper, the design equations are derived for the synthesis of a drag-link mechanism, with given output-link rotation and the corresponding input-link rotation. The design criterion used is based on the maximum capability of a drag-link mechanism to provide a given delay or advance in the output motion. The solutions are given as a single-valued parametric set of equations for the link lengths. The transmission-angle optimization is accomplished by the minimization of the maximum transmission-angle deviation from 90 deg. It is shown that the optimum design can be obtained by solving a cubic equation in a single parameter. Design charts for the optimum design of a drag-link mechanism were developed. It is also shown that there is a one-to-one correspondence between the design of a crank-and-rocker mechanism and the drag-link mechanism.

Design of Drag-Link Mechanisms With Optimum Transmission Angle

1983 ◽  
Vol 105 (2) ◽  
pp. 254-258 ◽  
Author(s):  
Lung-Wen Tsai
Keyword(s):  
Extreme Values ◽  
Angular Displacement ◽  
Output Link ◽  
Link Length ◽  
Design Charts ◽  
Link Mechanism ◽  
Transmission Angle ◽  
New Criterion ◽  
Four Bar Linkage ◽  
Drag Link

In this paper, a new criterion for the design of a drag-link mechanism with optimum transmission angle is established. The transmission angle, the angle between the coupler link and output link of a four-bar linkage, is considered to be optimized when its extreme values deviate equally from 90 deg. Based on this criterion, design equations and design charts are developed. It is shown that the optimum drag-link mechanism is a turning-block linkage. It is also shown that to displace the drag-link mechanism with optimum transmission angle from its minimum lag to its maximum lag position, the input link must always rotate 180 deg and the corresponding angular displacement of the output link depends only on the link-length ratio of the output link to the fixed-link.

Design of Centric Drag-Link Mechanisms for Delay Generation With Focus on Space Occupation

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Abdullah F. Al-Dwairi
Keyword(s):  
Length Ratio ◽  
Link Length ◽  
Link Mechanism ◽  
Maximum Delay ◽  
Transmission Angle ◽  
Quality Of Motion ◽  
Nonuniform Rotation ◽  
Drag Link ◽  
Space Occupation

Planar drag-link mechanism is a Grashofian four-bar chain with the shortest link fixed. In practice, the mechanism is used as a coupling between two shafts to convert uniform rotation of the driving shaft into a nonuniform rotation of the driven shaft. The nonuniformity in rotation is characterized by a cyclically increasing and decreasing delay (or advance) in the displacement of the driven shaft relative to that of the driving shaft. Drag-link synthesis problems include synthesizing the mechanism to generate a specified maximum delay. In a drag-link mechanism, the longer links make a full rotation about fixed pivots, which results in a relatively large installation space. This calls for designing drag-link mechanisms with a focus on space occupation, along with the traditional criteria of quality of motion transmission. Using position analysis, we investigate the relationships among mechanism space occupation, extreme transmission angle, and the generated maximum delay. Space occupation is represented by the link-length ratio of input link to fixed link. Given a desired maximum delay, the proposed approach suggests finding a unique extreme transmission angle value for which this link-length ratio is at a minimum. A closed-form solution to drag-link synthesis to generate a specified maximum delay is developed based on a compromise between quality of motion transmission and space occupation. For any drag-link designed by this compromise, the coupler link and the output crank are of the same length. Based on the obtained design equations, a graphical design solution and a method for evaluating space occupation are provided.

The Design of the Spherical Drag-Link Mechanism

1967 ◽  
Vol 89 (1) ◽  
pp. 177-181 ◽  
Author(s):  
A. H. Soni ◽  
L. Harrisberger
Keyword(s):  
Design Chart ◽  
Link Mechanism ◽  
Transmission Angle ◽  
Drag Link

The spherical drag-link mechanism has been designed using an approach based on minimum transmission angle. Explicit relationships have been derived for the required dimensions which satisfy the criteria of minimum transmission angle, and a design chart for the solution of spherical drag-link mechanisms (similar to that of Hain) is presented. Also, the seven cognates of the spherical drag-link mechanisms are identified and discussed.

Dynamic Force and Torque Analysis of Spherical Four Link Mechanisms

1983 ◽  
Vol 105 (3) ◽  
pp. 492-497 ◽  
Author(s):  
A. T. Yang ◽  
Sun Zhishang
Keyword(s):  
Dynamic Analysis ◽  
Optimum Design ◽  
Mass Distribution ◽  
High Speed ◽  
Dynamic Force ◽  
Arbitrary Mass ◽  
Link Mechanism ◽  
Torque Analysis ◽  
Analytical Expressions

In this paper we present a dynamic analysis of a general spherical four-link mechanism whose links have arbitrary mass distribution. Results, which are in explicit analytical expressions in terms of inertia-induced forces and moments in links, are useful for optimum design of the mechanism under high-speed operation.

Design of Multi-Recess Hydrostatic Journal Bearings for Minimum Total Power Loss

1974 ◽  
Vol 96 (1) ◽  
pp. 226-232 ◽  
Author(s):  
C. Cusano ◽  
T. F. Conry
Keyword(s):  
Rotational Speed ◽  
Power Loss ◽  
Load Capacity ◽  
Maximum Load ◽  
Journal Bearings ◽  
Design Criterion ◽  
Total Power ◽  
Eccentricity Ratio ◽  
Constant Ratio ◽  
Design Charts

The design problem is formulated for multi-recess hydrostatic journal bearings with a design criterion of minimum total power loss. The design is subject to the constraints of constant ratio of the recess area to the total bearing area and maximum load capacity for a given recess geometry. The L/D ratio, eccentricity ratio, ratio of recess area to total bearing area, and shaft rotational speed are considered as parameters. The analysis is based on the bearing model of Raimondi and Boyd [1]. This model is generally valid for low-to-moderate speeds and a ratio of recess area-to-total bearing area of approximately 0.5 or greater. Design charts are presented for bearings having a ratio of recess area-to-total bearing area of 0.6 and employing capillary and orifice restrictors, these being the most common types of compensating elements. A design example is given to illustrate the use of the design charts.

On the Derivation of Grashof-Type Moveability Conditions With Transmission Angle Control for Spatial Mechanisms

1987 ◽  
Author(s):  
J. Rastegar
Keyword(s):  
Approximation Techniques ◽  
Link Type ◽  
Revolute Joints ◽  
Spatial Mechanisms ◽  
Transmission Angle ◽  
Full Rotation ◽  
Drag Link

Abstract Derivation of Grashof-type conditions for spatial mechanisms that may include transmission angle limitations are discussed. It is shown that in general, different conditions need to be derived for each one of the existing configurations of the mechanism. In the absence of any transmission angle control, the conditions would be identical for pairs of configurations. As an example, for RRRSR mechanisms, Grashof-type conditions that ensure crank rotatability, the existence of a drag link type of mechanism, single or multiple changeover points, the possibility of full rotation at intermediate revolute joints, etc., are determined. A general discussion of the problems involved in such derivations, the use of approximation techniques to overcome some of the problems, and several other related subjects are presented.

SDAMP: Software for the Design and Analysis of Mechanical Presses

2000 ◽  
Author(s):  
Herbert E. Stumph ◽  
Andrew P. Murray
Keyword(s):  
Kinematic Analysis ◽  
Kinematic Synthesis ◽  
Link Mechanism ◽  
Mechanical Press ◽  
Analysis And Synthesis ◽  
Drag Link ◽  
Mechanism Kinematic ◽  
Functioning Mechanism

Abstract In this paper we introduce the MATLAB-based SDAMP (pronounced stamp) software for the analysis and synthesis of several mechanical press linkages. These linkages include the slider-crank and the four six-bar mechanisms formed by attaching a drag-link, crank-rocker, crank-shaper or Whitworth mechanism to a slider-crank. SDAMP performs four basic tasks: guided layout, kinematic analysis, mechanism refine and kinematic synthesis. Guided layout leads the user through joint selection to ensure a functioning mechanism. Kinematic analysis displays the position, velocity, acceleration and jerk of the sliding output versus the rotation of the input link. Mechanism refine allows the user to vary the geometry of an existing mechanism towards the goal of achieving a desired kinematic analysis. Lastly, kinematic synthesis determines the set of defect-free slider-cranks capable of achieving four precision points. All of these capabilities are integrated through a host of GUI driven MATLAB files in SDAMP.

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