V.V.P.INSTITUTE OF ENGINEENING AND

TECHNOLOGY

Represented by:Mr. DHORE NAGANATH MOHAN

Mr. KAPASE KHANDU DATTATRAYA

Under the guidance of:Prof. U. L. Anuse

CONTENTSIntroductionLiterature Survey DefinitionsTypes of straight line mechanismConstructionWorkingDegree of freedom AdvantageApplication References

INTRODUCTION Mechanism and mechanical systems result from the application of theory from many areas of mechanical engineering. The only way to full understand the motion of a mechanism is to physically interact with such a mechanism The work of this is based on study of relative motion between links and its mathematical proof.

LITERATURE SURVEY

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Burak B. et al, (2011) designed a parallel hinged door mechanism and its kinematics analysis by an analogy to a four bar mechanism .

Retheesh Kumar and Prof . Akash Mohanty (2013) investigated the design, synthesis and simulation of four bar mechanism to eliminate the plowing depth fluctuation in tractors.

Mulla Abdulkadar and Bhagyesh Deshmukh (2013) suggested that in the analysis of a four bar mechanism of various combinations, it is observed that the path traced by the link of mechanism of .

M.G. Bekker concluded that legged locomotion should be mechanically superior to wheeled or tracked locomotion over a variety of soil conditions and certainly superior for crossing obstacles .

DEFINITIONSLink: eg: Reciprocating steam engine.

Joint:

Kinematic pair:

TYPES OF STRAIGHT LINE MECHANISM

1) Approximate straight line mechanism

examples Watt’s linkage, Hoekens linkage, Tchibechiff’s

linkage, Roberts mechanism.

 2) Exact straight line mechanism. In the exact straight line mechanism are those in

which produces perfect linear output for example Sarrus

linkage, Peaucellier-lipkin linkage, Hart’s A-frame.

CONSTRUCTION

Fig. :Tchibechiffs straight line mechanism

WORKING

The Tchibechiff’s linkage is a mechanical linkage that converts rotational motion to approximate straight-line motion.

DEGREE OF FREEDOM

Kutzbach criterion for determining the number of degrees of freedom or movability (n) of a plane mechanism is

n = 3 (L – 1) – 2 j – hwhere,n=number of degree of freedomj = Number of binary joints, h = Number of higher pairs, and L = Number of links.n=number of degree of freedomFor Tchibechiff’s mechanism having,L=4, j=4,h=0. Then n=1For Peaucellier mechanism number of degree of freedom is

one i.e one movability.

 

Advantage:Tchibechiff’s linkage mechanism produces approximate staright line.

Smooth operation.

Compact in size.

Tchibechiff’s linkage mechanism is the first solution to generating line perpendicular to the line passing through rotation centers.

Produces rotary motion into partial and perfect straight line motion & vice-versa

Applications:-In toy industries for making robotic toys it has got many applications.

It can also be used for military purpose. By placing bomb detectors in the machines we can easily detect

the bomb without harmful to humans.

It can be used as heavy tanker machines for carrying bombs as well as carrying other military goods.

It can be used for space research where the wheeled machines have difficulties to move.

REFERENCESEuropean International Journal of Science and Technology Vol. 3 No. 8 October, 2014 65 Design

Khurmi Gupta, “Theory of machine’’

Rattan S.S., “Theory of Machines”, Third Edition, Page No. 19 – 21, Tata McGraHill Publication, New Delhi, 2009.

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