bracket,  2.  To  this  is  pivoted  a  blade,  4,  at  3.  For  normal  speed
of  the  engine,  the  spring,  .5,  gently  presses  the  inclined  surface,  6,
against  the  stationary  roller,  7.  In  this  position  the  blade,  4,
will  hit  the  lever,  S,  thus  opening  the  gas  valve,  9.     Should  the

*  Power  Quarterly,  Oct.  1.5,  1900.
t  Clerk,  Gas  and  Oil  Engines.
454


INTERNAL  COMBUSTION  ENGINES


speed,  however,  rise  above  normal,  the  upward  throw  given  to
the  blade  due  to  the  inclined  surface,  6,  sliding  against  the  roller,
7,  becomes  excessive,  and  blade  4  fails  to  assume  its  normal  posi-
tion by  the  time  the  lever  8  is  reached.  The  gas  valve  then  fails
to  open.
An  ingenious  modification  of  the  above  types  of  hit-and-miss
governors  used  by  Delamare*  is  shown  in  Fig.  14-12.     The  stem

of  the  inlet  slide  valve
carries  a  small  cylinder,

a,  into  which  is  fitted  a
stationary  piston,  b,  air-
tight. The  needle  valve,
c,  serves  to  adjust  the
velocity  of  air  escape
from  behind  the  piston,

b,  With  the  cylinder,  a,
in  the  extreme  right-hand
position,  air  is  admitted
behind  b  through  the
groove,  d.  As  a  travels
to  the  left  at  the  proper
speed,  the  air  is  com-
pressed, but  it  escapes
through  the  needle  valve,

c,  just  fast  enough  to
prevent  its  pushing  out-
ward the  plunger,  /,  in
the  branch  cylinder,  e,
against    the   spring.     In

Fig.  14-13.  ^j^jg  position  the  blade,  g,

hits  the  gas  valve  stem,  h.  For  an  excess  in  engine  speed,  cyl-
inder a  travels  to  the  left  so  fast  that  the  air  cannot  escape  at
the  proper  rate,  the  pressure  generated  forces  the  plunger,  /,  out-
ward, and  g  misses  the  valve  stem  as  shown  in  the  dotted  position.
