PROFESSOR T. A. HEARSON ON THE KINEMATICS OF MACHINES. 25 
Group O 4 , Containing 4 Turning Motions. 
Combination. 
Inversions. 
Notes and examples. 
OoOo 
oOoO 
Opposite links equal and parallel to one another. 
Gives one machine movement only, there being no change by 
“ inversion.” 
Mechanism, known as “ parallel-cranks,” employed for coupling 
together two pairs of driving wheels of locomotive engines. 
OOoo 
- 
1 
OOoo 
Opposite links equal but not parallel. 
Both cranks revolve in the same direction just as in the move¬ 
ment above. 
OooO 
Two cranks revolve in opposite directions called anti-parallel 
cranks. 
Group O 3 , Containing 3 Turning Motions. 
Combination. 
Inversions. 
Notes and examples. 
o0 2 oU 
oOVG 
0 2 oUo 
Mechanism consists of two equal short links in sequence and 
two equal longer ones. It is known as the Kite mechanism. 
o0 2 ol 
There are two finite links of equal length and the line of slide 
is parallel to the line joining the axes of tbe two o’s. 
o0 2 oI 
This movement has been used by Bernay in tbe design of a 
steam-pump. It may be compared with the common crank- 
and-connecting-rod engine, in which tbe length of the con¬ 
necting i'od is equal to the crank. The length of stroke is 
four times that of the crank. This is supposed to be the 
advantage due to the use of this mechanism for this purpose. 
0 2 oIo 
This, used in duplicate, has been employed by Parsons in the 
design of a high-speed engine. One. primary piece, the 
crank shaft, revolves at twice the speed of the other primary 
piece which is the cylinder. 
MDCCCXCVI.—A. 
£ 
