Valve control linkage

Claim 2

In combination: a tractor having a chassis; an operator''s station resiliently mounted on the chassis for limited movement relative thereto; a valve having a body rigidly mounted on the chassis and including a control member movable between open and neutral positions; a bracket rigidly mounted on the chassis; a pair of rigid links, one pivotally connected to the control member and the other to the bracket, pivotally interconnected at a point offset from the centerline through the pivotal connections between the one link and the control member and the other link and the bracket when the control member is in the neutral position so that movement of the interconnection between the links to an on-center position moves the control member to the open position and additional movement of the interconnection between the pair of links to a just over-center position locks the control member in the open position; a control lever pivotally mounted on the operator''s station; and a rigid link pivotally connected to the control lever and the pair of links to move the interconnection between the pair of links between the just over-center position and the offset position upon movement of the lever between first and second positions.

Claim 3

A combination as set forth in claim 1 wherein abutment means carried by one of the pair of links is engageable with the other of the pair of links to limit movement of the interconnection between the pair of links to the just over-center position.

Claim 4

A combination as set forth in claim 2 wherein tension spring means is anchored between the control lever and the operator''s station and has a line of force movable to opposite sides of the pivot axis of the control lever as the control lever is moved between its first and second positions to yieldably retain the control lever in its first and second positions.

Claim 5

In combination: a tractor having a chassis; an operator''s station mounted on the chassis; a valve having a body mounted on the chassis and including a control member movable to opposite sides of a neutral position to first and second open positions; a bracket mounted on the chassis; a pair of pivotally interconnected links pivotally connected to the control member and bracket to form an over center control linkage assembly with the interconnection between the links being in a first offset position with respect to the centerline through the pivotal connections between the links and the control member and the bracket when the control member is in the neutral position so that movement of the interconnection between the links in a one direction to an over-center position moves the control member to and locks the control member in the first open position and movement of the interconnection between the pair of links in an opposite direction to a second offset position moves the control member to the second open position; a valve control lever pivotally mounted on the operator''s station for movement to first and second sides of a neutral position; and link means interconnecting the lever and over center linkage assembly to move the interconnection between the pair of links from the first offset position to the over-center position and second offset position upon movement of the lever to the first and second sides respectively, of its neutral position.

Claim 6

In combination: a tractor having a chassis; an operator''s station mounted on the chassis; a valve having a body mounted on the chassis and including a control member movable to opposite sides of a neutral position to first and second open positions; a bracket mounted on the chassis; a pair of pivotally interconnected links pivotally connected to the control member and bracket to form an over center control linkage assembly with the interconnection between the links being in a first offset position with respect to the centerline through the pivotal connections between the links and the control member and the bracket when the control member is in the neutral position so that movement of the interconnection between the links in a one direction to an over-center position moves the control member to and locks the control member in the first open position and movement of the interconnection between the pair of links in an opposite direction to a second offset position moves the control member to the second open position; a valve control lever pivotally mounted on the operator''s station for movement to first and second sides of a neutral position; and link means interconnecting the lever and over center linkage assembly to move the interconnection between the pair of links from the first offset position to the over-center position and second offset position upon movement of the lever to the first and second sides respectively, of its neutral position.

Claim 7

A combination as set forth in claim 4 wherein spring means acting on the over center linkage assembly yieldably resists movement of the lever to the second side of its neutral position and returns the lever from the second side of its neutral position to its neutral position.

Claim 8

A combination as set forth in claim 5 wherein the spring means has a lost-motion connection with the over center linkage assembly whIch affords relative movement between the assembly and spring means as the lever is moved between its neutral position and the first side of its neutral position.

Claim 9

A combination as set forth in claim 6 wherein tension spring means is anchored between the control lever and operator''s station and has a line of force movable to opposite sides of the pivot axis of the control lever as the control lever is moved between its neutral position and the first side of its neutral position to yieldably retain the control lever in its neutral position and to the first side of its neutral position.