What configuration does a Hart mechanism possess________________?
Show answer Hide answer
Answer: B. six links
Explanation
The Hart mechanism is an exact straight-line generator consisting of six links. This linkage configuration avoids sliding joints entirely by utilizing only turning pairs. The precise arrangement of its six links generates a theoretically exact linear motion. Straight-line mechanisms convert rotary motion into linear motion without sliding guides. Harry Hart invented this linkage in the late nineteenth century as an improvement over Watt's linkage. It is an antiparallelogram-based linkage system that requires careful dimensional proportions.
Early steam engine valve gear designs utilized straight-line mechanisms to reduce friction losses. Precision measuring instruments incorporate linkage-based straight-line generators for accurate movement. Historical engineering achievements often highlight these clever geometric linkages before modern slides. Option A is incorrect because the mechanism does not require eight separate links to function. Option C describes a four-bar linkage which cannot generate exact straight lines alone. Option D overestimates the link count, as twelve links are unnecessary for this design.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. What are open pairs defined as in the study of mechanism joints__________________?
Show answer Hide answer
Answer: C. elements of pairs not held together mechanically
Kinematic pairs that rely solely on physical contact without mechanical fastening are classified as open pairs. Gravity or external external forces typically keep the contacting elements together during their operating c...
Q2. How is the pitch point on a cam profile defined_________________?
Show answer Hide answer
Answer: B. the point on cam pitch curve having the maximum pressure angle
The pitch point on a cam profile corresponds specifically to the location on the pitch curve having maximum pressure angle. This critical point helps engineers evaluate force transmission efficiency and potential followe...
Q3. How are lower pairs characterized in terms of surface contact___________________?
Show answer Hide answer
Answer: B. surface contact between the two elements when in motion
Lower pairs require mating elements to maintain broad surface contact during relative movement. This large contact area helps distribute mechanical loads effectively across the working surfaces. Surface contact distingui...
Q4. What characteristic defines the two elements forming a kinematic pair______________?
Show answer Hide answer
Answer: C. permit relative motion
The fundamental definition of a kinematic pair requires that its two constituent elements have constrained relative motion. Without relative motion between the connected parts, the assembly cannot function as a working m...
Q5. A rotating shaft supported inside a bearing represents what classification of kinematic pair________________?
Show answer Hide answer
Answer: A. lower pair
A rotating shaft supported inside a journal bearing features surface contact between the mating cylindrical elements. This extensive surface contact area classifies the shaft and bearing assembly as a lower kinematic pai...
Q6. When the fixed link in a kinematic chain is changed, how does it affect the relative motion of the remaining links_________________?
Show answer Hide answer
Answer: A. will remain same
Fixing a different link in a kinematic chain creates an inversion, which changes the relative motion of the remaining links.