What motion is produced by an elliptical trammel mechanism_________________?
Show answer Hide answer
Answer: C. two pairs turning and two pairs sliding
Explanation
An elliptical trammel mechanism consists of two turning pairs and two sliding pairs connected in a frame. The sliding blocks move inside perpendicular grooves while the bar pivots on turning pin joints. This specific combination of joints constrains the mechanism to trace a mathematically perfect ellipse. Elliptical trammels are classic mechanical inversions of the double slider crank kinematic chain. Turning pairs permit relative rotation, while sliding pairs restrict motion to straight line translation. Drafting instruments and specialized machine tools historically used this mechanism to draw elliptical shapes.
Kinematics courses use the elliptical trammel to teach degree of freedom analysis and mechanism inversions. Mechanical linkage design relies on understanding how mixing turning and sliding pairs creates complex curves. Industrial shapers and plotting machines incorporate similar multi-joint mechanisms for specialized cutting paths. All four pairs being turning describes a standard four bar linkage rather than an elliptical trammel. Three turning pairs and one sliding pair describes a standard single slider crank mechanism. Configurations with three or four sliding pairs fail to provide the necessary rotational degrees of freedom.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. Under what condition is a kinematic chain considered unconstrained_____________?
Show answer Hide answer
Answer: C. L.H.S. < R.H.S
When mobility calculations yield an excess of degrees of freedom, the chain is deemed unconstrained. The mathematical condition where LHS is less than RHS indicates multiple uncoordinated relative motions. Such chains ca...
Q2. Which of the following is an example of a spherical pair_____________________?
Show answer Hide answer
Answer: C. ball and socket joint
A ball and socket joint permits rotation in all directions, representing a spherical pair. The mating elements feature spherical surfaces that slide freely against each other. This geometry allows three degrees of rotati...
Q3. What type of relative motion occurs in a higher kinematic pair_____________________?
Show answer Hide answer
Answer: E. combination of sliding and turning
Higher kinematic pairs have point or line contact between the mating surfaces. Under mechanical loads, this concentrated contact geometry causes simultaneous sliding and turning. Cam and follower or gear tooth interactio...
Q4. What is the recommended maximum limit for the pressure angle in cam design________________?
Show answer Hide answer
Answer: D. 30°
The recommended maximum limit for the pressure angle in cam design is thirty degrees. Exceeding this thirty-degree limit causes excessive side thrust and follower binding in guides. Maintaining a lower pressure angle ens...
Q5. How many links and instantaneous centers are present in a reciprocating engine mechanism ___________________?
Show answer Hide answer
Answer: E. 4, 6
A reciprocating engine mechanism has four links and six instantaneous centers. Kennedy's theorem calculates instantaneous centers using the formula n times n minus one over two. For four links, evaluating four times thre...
Q6. What is the primary mechanical function of a structural link________________?
Show answer Hide answer
Answer: D. all of the above
Structural links act as rigid bodies that transmit forces throughout a machine assembly. Links also maintain correct relative distances and guide other moving components along paths. Therefore, structural links perform a...