Transmission control circuit

Claim 2

In a variable speed transmission having a plurality of fluid operated mechanisms with a first of said mechanisms being operative when said transmission is engaged in a forward direction and a second mechanism being operative when said transmission is engaged in a reverse direction, a hydraulic circuit for supplying fluid to said mechanisms, said circuit including a source of fluid; pump means supplying fluid under pressure from said source; a control valve; conduit means between said source, pump means, control valve and fluid operated mechanisms, said conduit means including first and second conduits respectively leading to said first and second mechanisms; and check valve means between said first and second conduits, said check valve means accommodating limited flow of fluid from one of said first and second conduits to the other of said first and second conduits during initial supply of fluid under pressure to said one of said first and second conduits to delay the pressure rise in the associated fluid operated mechanism, said check valve means including a tube extending vertically with a member vertically shiftable in said tube, said member normally being located in a lowermost position in said tube blocking flow of fluid in said tube.

Claim 3

The combination as defined in claim 1, in which said tube has a constant diameter openIng along a major portion of its length and reduced diameter portions adjacent opposite ends; and in which said member has a diameter less than the diameter of the major portion of said opening and greater than the reduced diameter portions to accommodate flow while said member is spaced from said reduced diameter portions.

Claim 4

The combination as defined in claim 1, in which said member is a circular ball.

Claim 5

In a variable speed transmission having a plurality of fluid operated mechanisms with a first mechanism being operative by supplying fluid under pressure thereto to operate said transmisssion in a lowermost speed in the forward direction and a second mechanism being operative by supplying fluid under pressure thereto to operate said transmission in a reverse direction; and a hydraulic circuit for supplying fluid to said mechanisms, said circuit including first and second conduits respectively connected to said first and second mechanisms; control valve means connected to said conduits; a reservoir; pump means; means connecting said reservoir and pump means to said control valve means, said control valve means being operable to selectively connect said reservoir and pump means to said conduits; and valve means interconnecting said conduits, said valve means including a vertical tube having an opening of common diameter throughout its length, first means on the upper end of said tube and having a reduced diameter opening connecting said tube to said first conduit, second means on the lower end of said tube and having a reduced diameter opening connecting said tube to said second conduit, and a ball having a diameter less than said common diameter and greater than said reduced diameters, said ball being freely movable in said tube and normally being located adjacent said second means to block flow of fluid from said first conduit to said second conduit, said ball being vertically movable in said tube when said pump means is connected to said second conduit and said first conduit is connected to said reservoir to delay the pressure rise of the fluid supplied to said second mechanism.

Claim 6

In a variable speed transmission having a plurality of fluid operated mechanisms with a first mechanism being operative by supplying fluid under pressure thereto to operate said transmisssion in a lowermost speed in the forward direction and a second mechanism being operative by supplying fluid under pressure thereto to operate said transmission in a reverse direction; and a hydraulic circuit for supplying fluid to said mechanisms, said circuit including first and second conduits respectively connected to said first and second mechanisms; control valve means connected to said conduits; a reservoir; pump means; means connecting said reservoir and pump means to said control valve means, said control valve means being operable to selectively connect said reservoir and pump means to said conduits; and valve means interconnecting said conduits, said valve means including a vertical tube having an opening of common diameter throughout its length, first means on the upper end of said tube and having a reduced diameter opening connecting said tube to said first conduit, second means on the lower end of said tube and having a reduced diameter opening connecting said tube to said second conduit, and a ball having a diameter less than said common diameter and greater than said reduced diameters, said ball being freely movable in said tube and normally being located adjacent said second means to block flow of fluid from said first conduit to said second conduit, said ball being vertically movable in said tube when said pump means is connected to said second conduit and said first conduit is connected to said reservoir to delay the pressure rise of the fluid supplied to said second mechanism.

Claim 7

A variable speed transmission as defined in claim 4, in which said ball is seated against the reduced diameter opening in said first means while fluid under pressure is being delivered to said second mechanism and in which said ball moves downward in said tube when said second conduit is connected to said reservoir.