Generic Models for Designing Dwell Mechanisms: A Novel Kinematic Design of Stirling Engines as an Example

1991 ◽  
Vol 113 (4) ◽  
pp. 446-450 ◽  
Author(s):  
S. Kota
Keyword(s):  
Design Models ◽  
Circular Arc ◽  
Generic Models ◽  
Straight Line ◽  
Stirling Engines ◽  
Finite Set ◽  
Single Input ◽  
Motion Characteristics ◽  
Generic Design ◽  
Four Bar Linkage

The desirable motion characteristics of mechanisms are so implicit that they are difficult to express analytically. Our design methodology involves development of generic design models through abstractions of entire emotion characteristics. We have developed a finite set of generic models (for straight-line, circular-arc, and dwell mechanisms) that represents the entire design space in the sense that a given design specification falls under at least one of the generic design models. This paper presents the generic design models for four-bar straight-line, circular arc, and six-bar dwell linkage mechanisms. The models presented here provide ready-made designs for many dwell applications. We have also presented a new concept in mechanisms design in which multiple coupler points on a four-bar linkage are used to drive different output dyads resulting in multiple dwell outputs. Finally, a new mechanism for the opposed piston stirling engine is presented to illustrate the use of generic design models and the application of a single-input controlling dual output motions with dwells.

Optimum Design of Curve-Generating Linkages With Inequality Constraints

1967 ◽  
Vol 89 (1) ◽  
pp. 144-151 ◽  
Author(s):  
R. L. Fox ◽  
K. D. Willmert
Keyword(s):  
Mathematical Programming ◽  
Inequality Constraints ◽  
Problem Area ◽  
Mathematical Programming Problem ◽  
Iterative Technique ◽  
Circular Arc ◽  
Open Questions ◽  
Design Variables ◽  
Straight Line ◽  
Four Bar Linkage

The problem of synthesizing a four-bar linkage is presented as a mathematical programming problem. The objective is to synthesize a four-bar linkage whose coupler point will generate, as closely as possible, a given curve, and whose crank rotations will be as close as possible to desired values. Constraints are imposed on the design variables which force the result to be a four-bar linkage, limit the forces and torques within the linkage, restrict the location of the pivot points, limit the lengths of the links, and so on. The solution is found using an iterative technique with the aid of a digital computer. Several examples are presented which demonstrate the effectiveness of this approach. They include generation of a straight line, a figure eight, and a portion of a circular arc (previously investigated using a method developed by Freudenstein and Sandor). The work on this problem area is still in progress and there remain a number of open questions and unexplored alternatives.

Development of Knowledge Base for Designing Linkage-Type Dwell Mechanisms: Part 1—Theory

1987 ◽  
Vol 109 (3) ◽  
pp. 308-315 ◽  
Author(s):  
Sridhar Kota ◽  
Arthur G. Erdman ◽  
Donald R. Riley
Keyword(s):  
Expert System ◽  
Circular Arc ◽  
Design Charts ◽  
Circular Arcs ◽  
Straight Line ◽  
Parallel Motion ◽  
Curvature Theory ◽  
Path Curvature ◽  
Motion Characteristics ◽  
Straight Lines

Linkage-type mechanisms have certain advantages over cams for dwell applications. The design of a typical six-link dwell mechanism involves adding an output dyad to the basic four-bar mechanism that generates either a circular arc or a straight line portion of the coupler curve. The entire motion characteristics of these four-bar mechanisms should be considered in order to design a suitable dwell linkage. Part 1 of this paper is devoted to the study of four-bar linkages which generate straight line, circular arc and symmetrical curves. Part 2 discusses how the design experience gained in this study can be applied to develop an expert system for designing linkage-type dwell mechanisms. Using path curvature theory and design charts developed by Tesar, et al., hundreds of four-bar straight-line mechanisms are systematically investigated. Based on the typical shapes of coupler curves these mechanisms are then classified. A synthesis technique has been developed to design four-bar mechanisms for circular arc generation. Symmetrical coupler curves with straight-line or circular-arc segments, which are required for designing double-dwell mechanisms, are studied. This paper is part of the research that is underway to develop an “expert system” for designing mechanisms to generate straight lines, circular arcs, symmetrical curves, parallel motion and dwell.

Duplex Spread Blade Method for Cutting Hypoid Gears with Modified Tooth Surface

1998 ◽  
Vol 120 (3) ◽  
pp. 441-447 ◽  
Author(s):  
K. Kawasaki ◽  
H. Tamura
Keyword(s):  
Cutting Edge ◽  
Tooth Surface ◽  
Radius Of Curvature ◽  
Large Radius ◽  
Ring Gear ◽  
Circular Arc ◽  
Hypoid Gears ◽  
Manufacturing Method ◽  
Straight Line

In this paper, a duplex spread blade method for cutting hypoid gears with modified tooth surface is proposed. The duplex spread blade method provides a rapid and economical manufacturing method because both the ring gear and pinion are cut by a spread blade method. In the proposed method, the nongenerated ring gear is manufactured with cutting edge that is altered from the usual straight line to a circular arc with a large radius of curvature and the circular arc cutting edge produces a modified tooth surface. The pinion is generated by a cutter with straight cutting edges as usual. The main procedure of this method is the determination of the cutter specifications and machine settings. The proposed method was validated by gear manufacture.

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.

scholarly journals A Straight Line and a Circular Arc Generators for a Dot Display

1973 ◽  
Vol 27 (12) ◽  
pp. 936-941
Author(s):  
Takahiko Kamae ◽  
Toshio Hoshino ◽  
Masao Suzuki
Keyword(s):  
Circular Arc ◽  
Straight Line

scholarly journals Optimal synthesis of a four-bar linkage by method of controlled deviation

2004 ◽  
Vol 31 (3-4) ◽  
pp. 265-280 ◽  
Author(s):  
Radovan Bulatovic ◽  
Stevan Djordjevic
Keyword(s):  
Objective Function ◽  
Optimal Synthesis ◽  
Straight Line ◽  
Individual Comparison ◽  
Four Bar Linkage ◽  
The Given ◽  
Initial Selection ◽  
Selection Of ◽  
Process Calculation ◽  
Made In

This paper considers optimal synthesis of a four-bar linkage by method of controlled deviations. The advantage of this approximate method is that it allows control of motion of the coupler in the four-bar linkage so that the path of the coupler is in the prescribed environment around the given path on the segment observed. The Hooke-Jeeves?s optimization algorithm has been used in the optimization process. Calculation expressions are not used as the method of direct searching, i.e. individual comparison of the calculated value of the objective function is made in each iteration and the moving is done in the direction of decreasing the value of the objective function. This algorithm does not depend on the initial selection of the projected variables. All this is illustrated on an example of synthesis of a four-bar linkage whose coupler point traces a straight line, i.e. passes through sixteen prescribed points lying on one straight line. .

Synthesis of a Large Oscillation Four-Bar Mechanism

1997 ◽  
Author(s):  
Gloria K. Starns ◽  
Donald R. Flugrad
Keyword(s):  
Reduced Gradient Method ◽  
Large Oscillation ◽  
Oscillation Mechanism ◽  
Straight Line ◽  
Transmission Angle ◽  
Reduced Gradient ◽  
Generalized Reduced Gradient ◽  
Angular Oscillations ◽  
Four Bar Linkage ◽  
Effective Transmission

Abstract This paper demonstrates procedures implemented for the synthesis of a four-bar mechanism that produces large angular oscillations of the output member while maintaining effective transmission angles. The mechanisms are modeled as being driven by a force applied at the coupler link. Additionally this force’s line of action is constrained to occur along an approximate straight line. This research was conducted out of the need for a device that is capable of retraction of the horizontal tool bar housed on the back of a tractor. The tool bars accommodate the implements required to accomplish the numerous tasks of the farmer, i.e. row markers, sprayer arms, planters, etc. Upon retraction of the tool bar so that it is parallel to ground, the appropriate tools are lowered to their working position. As the length of these bars increases, a savings of time and increased productivity is realized. Kurt Hain makes the following observation regarding large oscillation mechanisms in [1]: “It would be very difficult to solve this problem with one four-bar linkage, because it is difficult to design a four-bar linkage having such a large oscillation of a crank without running into problems of poor transmission angle characteristics; it might be possible to use linkages in combinations with gears, but this would make the mechanism more expensive, less efficient, and probably noisier.” In this study simulated annealing, a genetic algorithm and the generalized reduced gradient method are used to produce mechanisms with large angular oscillations of the output member and transmission angles that vary by as little as 20° from 90°. A comparative analysis of each of the optimization procedures is presented with observations regarding the efficacy of each method in the solution of the large oscillation mechanism.

Design Model of the Tunnel Axis and its Algorithm Implementation

2011 ◽  
Vol 103 ◽  
pp. 570-577
Author(s):  
Yue Qiang Li ◽  
Ya Ke Liu
Keyword(s):  
Construction Projects ◽  
Tunnel Boring Machine ◽  
Calculation Model ◽  
Transition Curve ◽  
Underground Construction ◽  
Design Models ◽  
Circular Arc ◽  
Tunnel Boring ◽  
Urban Rail ◽  
Algorithm Implementation

With a large number of construction projects building in urban rail construction, it’s very necessary for researching on the construction axis. Construction axis of the subway is consisted of line segment, circular arc segment and transition curve. The paper introduces design models and algorithms of the tunnel boring machine (TBM) axis (DTA). By analyzing the DTA characteristics of each curve, summing up their general characters, we ultimately make a unified common algorithm and geodetic coordinate calculation model of the design axis in horizontal and vertical planes. It will be very useful for the process of underground construction.

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