weak material of the belt

weak material of the pulley

uneven extensions and contractions of the belt when it passes from tight side to slack side

expansion of the belt

A round bar in a round hole form a turning pair

A square bar in a square hole form a sliding pair

A vertical shaft in a foot step bearing forms a successful constraint

all of the above

60 to 80 r.p.m.

80 to 100 r.p.m.

100 to 200 r.p.m.

200 to 300 r.p.m.

length of pair of contact to the circular pitch

length of arc of contact to the circular pitch

length of arc of approach to the circular pitch

length of arc of recess to the circular pitch

Scott-Russell's mechanism

Hart's mechanism

Peaucellier's mechanism

all of these