SAFETY INTERLOCK SYSTEM

• US 3,736,729 A
• Filed: 02/28/1972
• Issued: 06/05/1973
• Est. Priority Date: 02/28/1972
• Status: Expired due to Term

• Current Assignee: Clifford D. Peterson
• Original Assignee: Clifford D. Peterson
• Inventors: Peterson, Clifford D.
• Primary Examiner(s): Chamblee, Hugh R.
• Assistant Examiner(s): Oliff, J. A.
• Application Number:
  US05/229,646
• Time in Patent Office: 463 Days
• Field of Search: 56/10.5
• US Class Current: 56/10.5
• CPC Class Codes: A01D 2101/00 Lawn-mowers
• CPC Class Codes: A01D 34/64 mounted on a vehicle, e.g. a tractor, or drawn by an animal or a vehicle A01D34/695 takes precedence

Abstract

A safety interlock system for a riding lawn mower powered by an internal combustion engine which includes a switch responsive to the engagement of the transmission, a switch responsive to the engagement of the cutting blade, a switch responsive to the operation of the engine and an ignition switch. The transmission, cutting blade and engine switches are in a circuit connected to ground whereby the ignition switch must be on and the transmission and cutting blade disengaged to start the engine. Also disclosed is an additional switch responsive to the occupation of the driver'"'"''"'"'s seat disposed in parallel circuit with the engine switch, whereby, to start the engine, irrespective of the occupation of the seat, the cutting blade and transmission must be disengaged. If the operator leaves the driver'"'"''"'"'s seat with either the cutting blade or the transmission engaged, the engine will stop.

Claims

1. A safety interlock system for a riding lawnmower having at least one powered wheel and a powered cutting blade which comprises, in combination:

i. an internal combustion engine having a magneto, a fly wheel and, a blower housing enclosing said fly wheel wherein the fly wheel blows air during the operation of the engine;

ii. a transmission mechanism for transmitting power from the engine to the powered wheel having a neutral disengaged position and a power engaged position;

iii. a cutting engaging mechanism, for transmitting power from the engine to the cutting blade, having a blade engaged position and a blade disengaged position;

iv. an ignition switch in circuit with the magneto and ground having an off position and an on position, said ignition switch grounding the magneto when the ignition is in an off position and disconnecting the magneto from ground when in an on position, said ignition switch required to be in an on position to start the engine;

v. an engine switch in circuit with the magneto responsive to the operation of the engine having an open and closed position;

said engine switch being in an open position when the engine is being operated and in closed position when the engine is stopped, said engine switch being positioned contiguous with the blower housing and being operative to open in response to the flow of air passed through the blower housing when the engine is operating, said switch further characterized as an air vane switch having an actuating vane positioned within the blower housing;

vi. a transmission switch in circuit with the engine switch and ground, responsive to the position of the transmission mechanism having an open and closed position, said transmission switch being in an open position when the transmission mechanism is in a disengaged position and in a closed position when the transmission mechanism is in an engaged position;

vii. a cutting blade switch in circuit with the engine switch and ground responsive to the position of the cutting engaging mechanism having an open and closed position, said cutting blade switch being in an open position when the cutting blade is disengaged, and in a closed position when the blade is engaged; and

, viii. said transmission and cutting switches grounding the magneto when in a closed position and the engine is not being operated, ix. said engine starting operation only when the ignition switch is on, the transmission is disengaged and the blade disengaged and will continue operation, once started, with the transmission and blade in any position.

2. The safety interlock system of claim 1 wherein the air vane switch is in an open position when the flow of air in the housing exceeds a first predetermined value and is in a closed position when the flow of air is below a second predetermined value, said second value being less than the first value.

3. In a riding lawnmower equipped with a movable chassis, a riding seat on said chassis, an internal combustion engine having a magneto and a flywheel, a blower housing containing said flywheel;

and, disengagable transmission and cutting blade engaging mechanisms, the improved safety interlock system which comprises;

i. an ignition switch in circuit with the magneto and ground, said ignition switch having an open and closed position grounding the magneto when closed so that the ignition switch must be open to start the engine;

ii. an engine switch in circuit with the magneto responsive to the operation of the engine said engine switch being in an open position when the engine is being operated and in a closed position when the engine is stopped;

iii. said engine switch comprising an air vane switch having an actuating vane positioned withiN the blower housing, said vane opening the engine switch in response to air flow in the blower housing when the engine is running;

iv. a seat switch in parallel circuit with the engine switch responsive to the occupation of the riding seat having an open position and closed position, said seat switch being in an open position when the seat is occupied and in a closed position when the seat is vacant;

v. a transmission switch in circuit with the engine and seat switches and ground responsive to the engagement of the transmission mechanism having an open and closed position;

said transmission switch being in open position when the transmission is disengaged and in a closed position when the transmission is engaged;

vi. a cutting blade switch in circuit with the engine and seat switches and ground responsive to the engagement of the cutting blade engaging mechanism having an open and closed position, said cutting blade switch being in an open position when the cutting mechanism is disengaged and being in a closed position when engaged; and

vii. said transmission and cutting switches grounding the magneto when in a closed position and the engine is not being operated irrespective of the occupation of the riding seat and allowing the engine to start only if both the transmission and cutting blade engaging mechanism are disengaged and permitting continued operation when started with either the transmission or cutting blade engaged only if the riding seat is occupied.

4. A safety interlock system as in claim 3 wherein the air vane switch is in an open position when the flow of air in the housing exceeds a first predetermined value and is in a closed position when the flow of air is below a second predetermined value, said second value being less than the first value.