Speed control and transmission vent valve

Apparatus (10) for generating a control signal, comprising:

• (a) a first valve (12) having a fluid outlet (30);
• (b) a second valve (14) having a first fluid inlet (64), a second fluid inlet (66), an openable fluid outlet (70), and a spool (62 or 62') being movable in response to fluid in said first fluid inlet (64) and said second fluid inlet (66) between a first position, a second position and a third position at which said openable fluid outlet (70) is open to produce the control signal;
• (c) a first fluid passage (112) having a first end (114) coupled to said fluid outlet (30) of said first valve (12) and a second end (116) coupled to said first fluid inlet (64);
• and
• (d) two-state switch means (16) for communicating fluid in said first fluid passage (112) to said second inlet (66) in response to a first state of said switch means (16) to move said spool (62 or 62') from said first position to said second position and for communicating fluid in said first fluid passage (112) to said first inlet (64) in response to a second state of said switch means (16) to move said spool (62 or 62') from said second position to said third position.

A speed control and transmission vent valve (10), comprising:

• (a) a first valve (12) having a pair (34) of differential pressure control openings, a fluid supply inlet (24), a fluid supply outlet (30), and a manually movable spool (22) having a first land (48) continually opening said fluid supply inlet (24) to said fluid supply outlet (30) and a second land (52) controlling the pressure differential in said pair (34) of differential pressure control openings;
• (b) a second valve (14) having a first fluid inlet (64), a second fluid inlet (66), a third fluid inlet (74), a first fluid outlet (72), a second fluid tank outlet (68) and a third fluid control signal outlet (70), a first passage (76) communicating said first fluid outlet (72) with said third fluid inlet (74), an automatically movable spool (62 or 62') having a first land (92), a second land (94) and a third land (96) having one side open to said third fluid inlet (74), said automatically movable spool (62 or 62') being movable between an initial position, an intermediate position and a final position, wherein,
• (i) at said initial position said third land (96) opens said control signal outlet (70) to said tank outlet (68), said first land (92) opens said second fluid inlet (66) to said first fluid outlet (72), and said first land (92) and said second land (94) trap fluid received therebetween from said first inlet (64),
• (ii) at said intermediate position said third land (96) opens said control signal outlet (70) to said tank outlet (68), said first land (92) closes said second inlet (66) to said first passage (76), and said first land (92) and said second land (94) open therebetween said first fluid inlet (64) to said first fluid outlet (72), and
• (iii) at said final position, said third land (96) closes said control signal outlet (70) to said tank outlet (68), said first land (92) closes said second fluid inlet (66) to said first fluid outlet (72), and said second land (94) opens said first fluid inlet (64) to said control fluid outlet (70);
• (c) a second fluid passage (112) having a first end (114) coupled to said supply outlet (30) and having a second end (116) coupled to said first fluid inlet (64);
• and
• (d) switch means (16) for controlling the flow of fluid in said second passage (112) between said first fluid inlet (64) and said second fluid inlet (66).