Neutral start switch and backup alarm switch, and method of assembling the same for a manual displacement control for a hydrostatic transmission

A method of adjusting for neutral on a manual control for controlling the fluid displacement of a variable displacement unit in a hydrostatic transmission, the control having a body member and a cam means releasably and operatively interconnecting an input shaft extending into the body member for rotation with the input shaft and selectively interconnecting the input shaft and an electrical switch mounted on the body member, the method comprising:

• providing yieldable retention means interconnecting said body member and said input shaft to normally maintain said switch in a neutral position;
• releasing said cam means from operative interconnection between said input shaft and said switch;
• adjusting the position of said cam means with respect to said switch so that said cam means will maintain a generally symmetrical deadband for said switch in said neutral position;
• and then
• fixing the position of said cam means with respect to said input shaft and said switch.

A method of adjusting for neutral on a manual control for controlling the fluid displacement of a variable displacement unit in a hydrostatic transmission, the control having a body member and a cam means having a cam plate releasably and operatively interconnecting an input shaft extending into the body member for rotation with the input shaft and selectively interconnecting the input shaft and an electrical switch mounted on the body member, the method comprising:

• providing yieldable retention means interconnecting said body member and said input shaft to normally maintain said switch in a neutral position;
• releasing said cam plate from operative interconnection between said input shaft and said switch;
• adjusting the position of said cam plate with respect to said switch and said input shaft so that said cam plate will maintain a generally symmetrical deadband for said switch in said neutral position;
• and then
• fixing the position of said cam plate with respect to said input shaft and switch.

A manual control for controlling the fluid displacement of a variable displacement unit in a hydrostatic transmission, comprising:

• a body member having a first cavity exposed to hydraulic pressure from the variable displacement unit, a second cavity having a passage intersecting said first cavity, and sealing means operably positioned in said passage such that said second cavity is free of said hydraulic pressure;
• a manually operated input shaft extending into said first cavity;
• an electrical switch mounted on said body member and extending into said second cavity and having an actuating member capable of electrically and individually actuating at least two separate electrical circuits;
• cam means operatively connected to said input shaft and positioned to operatively contact said electrical switch such that a first increment of movement of said cam means by said input shaft will open one of said circuits, and a second increment of movement of said cam means will close the other of said circuits;
• and
• said switch means being normally in a closed and neutral position.

A manual control for controlling the fluid displacement of a variable displacement unit in a hydrostatic transmission, comprising:

• a body member having a first cavity exposed to hydraulic pressure from the variable displacement unit, a second cavity having a passage intersecting said first cavity, and sealing means operably positioned in said passage such that said second cavity is free of said hydraulic pressure;
• a manually operated input shaft extending into said first cavity;
• an electrical switch mounted on said body member and extending into said second cavity and having an actuating member capable of electrically and individually actuating at least two separate electrical circuits;
• cam means operatively connected to said input shaft and positioned to operatively contact said electrical switch such that a first increment of movement of said cam means by said input shaft will open one of said circuits, and a second increment of movement of said cam means will close the other of said circuits;
• said switch means being normally in a closed and neutral position;
• and
• torsional spring means operably secured to said body member and said input shaft to normally maintain said switch in said neutral position wherein one circuit is closed and the other circuit is open.