US 3885112 A
An engine tilt shut-off device comprising a housing with a vertically slidable plunger disposed therein. The plunger has depending therefrom a drag leg which engages the surface beneath a power driven vehicle and which maintains the plunger in an upper or operative position within the housing. A coil spring urges the plunger downwardly. When uneven terrain or other subadjacent surface is encountered, the drag leg drops downwardly allowing the plunger to be moved downwardly at the urging of the coil spring. Conductive means comprising terminals on opposite sides of the plunger and which are connected in a power supply circuit for the engine, are operated on downward movement of the plunger. A conductive cap on the plunger, which normally completes the power supply circuit through the terminals is allowed to move downwardly whereby to open the circuit and to effect a positive and automatic engine tilt shut-off.
Description (OCR text may contain errors)
United States Patent [1 1 Duncan VEHICLE CARRIED ENGINE TILT SHUT-OFF SWITCH  Inventor: Vinal Duncan, 35 Lindsley Dr.,
Wolcott, Conn. 06716  Filed: Nov. 15, 1973  Appl. No.: 416,290
 US. Cl. ZOO/61.44; 200/153 A; 200/163  Int. Cl HOlh 3/16; HOlh 15/14  Field of Search.... 200/16 B, 16 C, 16 D, 52 A, ZOO/61.2, 61.26, 61.39, 61.44, 153 A, 159 R, 160,161,163, 241, 243, 252, 257; 340/52 H,
[ 1 May 20, 1975 Primary Examiner-James R. Scott Attorney, Agent, or Firm-McCormick, Paulding & Huber 5 7 ABSTRACT An engine tilt shut-off device comprising a housing with a vertically slidable plunger disposed therein. The plunger has depending therefrom a drag leg which engages the surface beneath a power driven vehicle and which maintains the plunger in an upper or operative position within the housing. A coil spring urges the plunger downwardly. When uneven terrain or other subadjacent surface is encountered, the drag leg drops downwardly allowing the plunger to be moved downwardly at the urging of the coil spring. Conductive means comprising terminals on opposite sides of the plunger and which are connected in a power supply circuit for the engine, are operated on downward movement of the plunger. A conductive cap on the plunger, which normally completes the power supply circuit through the terminals is allowed to move downwardly whereby to open the circuit and to effect a positive and automatic engine tilt shut-off.
10 Claims, 4 Drawing Figures PATENTED m 3,885,112
VEHICLE CARRIED ENGINE TILT SHUT-OFF SWITCH BACKGROUND OF THE INVENTION The engine tilt shut-off is particularly adapted for lawn mowers of the push, self-propelled and riding type together with garden tractors and various other small power driven vehicles. When such a vehicle is tipped over, serious injury to the operator may ensue. For example, a rotating blade of a rotary power mower exposed in a sidewise or upward direction is quite obviously an extremely hazardous device. Further, fire may result from a live ignition system and spilling gas.
SUMMARY OF THE INVENTION It is the general object of the present invention to provide an improved engine tilt shut-off device which will operate automatically and in a positive manner to effect immediate engine shut-off operation when a vehicle carrying the device exceed a predetermined angle to tilt.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of a power driven riding lawn mower equipped with the engine tilt shut-off device of the present invention.
FIG. 2 is a front elevational view of the power driven lawn mower at a predetermined angle of tilt.
FIG. 3 is a vertical sectional view through an engine tilt shut-off device constructed in accordance with the present invention, the device being shown in a condition of engine operation.
FIG. 4 is a vertical sectional view similar to FIG. 3 but showing the engine tilt shut-off device in a condition of engine shut-off.
DESCRIPTION OF PREFERRED EMBODIMENTS Referring particularly of FIGS. 1 and-2, it will be observed that an engine tilt shut-off device indicated generally at is mounted approximately centrally on a power driven lawn mower 12 of the riding type. The device is exposed downwardly and has a drag member 14 depending therefrom and enagaging at its lower end portion 16, the terrain or other surface 18 upon which the vehicle rests. The terrain or other surface 18 may, of course, vary in contour and, as shown, in FIG. 2, the mower 12 may in the course of its operation, reach an angle of inclination which may result in or at least approach a tipping action of the mower. The angle shown in FIG. 2 may not necessarily result in a tipping action of the mower, but it is to be understood that the tilt device of the present invention may be employed to effect an engine shut-off operation prior to tipping as well as after the tipping action. Thus, a shut-off operation may prevent tipping of the vehicle or, alternatively, the device may be employed merely as a safety feature subsequent to tipping.
In FIG. 2, it will be observed that the drag member 14 is somewhat extended by the angle of inclination of the mower 12 and the lower end portion 16 thereof has been raised to a point where it is out of contact with the terrain 18. In this condition, the engine tilt shut-off device operates effectively to automatically and positively bring about an engine shut-off operation.
In FIGS. 3 and 4, it will be observed that a housing 20 is provided with a cylindrical opening 22 which extends vertically and which is open at the bottom 24.
The opening 22 slidably receives a plunger 26 which takes a cylindrical form and, in the presently preferred construction, comprises an aluminum body member carrying a brass cap 28 secured in place by means of a mounting screw 30. Disposed atop the plunger cap 28 and within the cylindrical opening 28 is a coil spring 32 which serves as a resilient biasing means urging the plunger and its cap 28 downwardly.
At a lower end portion, the plunger 26 carries a small cylindrical plate 34 secured thereto by suitable screws 36, 36 and provided with a central opening 38. The opening 38 preferably has a cone-shaped outer portion and a spherical inner portion 40 for receiving a partishperical upper end portion of drag member 44. The drag member 44 depends from the plunger 26 and is preferably J-shaped with the longer leg thereof connected with the plunger. Thus, if the device is moved in the direction of the arrow 46, the rounded lower portion of the drag member traverses the terrain therebeneath, and a tendency to catch on rough portions of the terrain is overcome. The parti-spherical upper portion 42 and its cooperating socket 40 provide, together with the cone-shaped portion of the opening 38, for minor adjustments of the drag member.
As will be apparent, the slidable member 26 has an upper position as in FIG. 3 which serves as an operative position and one or more lower positions as in FIG. 4 wherein the device is inoperative. In the operative position, the engine tilt device serves to complete a circuit which may be connected in the power supply of the engine and in its inoperative condition the device serves to effect an engine shut-off operation. The manner in which the device is connected in an electrical power supply for an engine may vary widely within the scope of the invention, and it will only be necessary herein to illustrate electrical conductors 48 and 50 which may, for example, extend from a power supply to a spark plug. Contact members associated with the wires 48, 50 may vary widely in form, but, in the presently preferred embodiment, generally C-shaped contact members 52, 52 are provided within the housing 20. The body portions of the C-shaped contact members 52, 52 are disposed inwardly in the cylinder opening 22 so as to engage and effect electrical contact with the cap 28 as shown in FIG. 3. The central portions of the C-shaped members 52, 52 are preferably in a flexed condition so as to maintain firm and frictional contact with the plunger 26. Rear or outer free portions 54 of the C- shaped member are clamped beneath the heads 56, 56 of terminal members and against insulating blocks 58, 58. Thus, an electrical circuit is completed from the wire 48 through a body portion 60 of a terminal, its head 56, the C-shaped contact 52 at the left end FIG. 3, the head 56 and the body 60 of the right hand terminal. Connecting screws 62, 62 respectively connect end portions of the wires 48 and 50 to the terminal members 56, 56.
From the foregoing, it will be apparent that the body 20 of the engine tilt shut-off device may be appropriately mounted on a vehicle as by means of mounting brackets 64, 64. With the vehicle in operation and with the drag element 44 in engagement with the terrain, the device will assume the condition of FIG. 3 and no detrimental effect on operation is encountered. When the terrain is inclined from side to side or from front to rear, and when the drag element 44 is allowed to move downwardly as in FIG. 4, the condition of FIG. 4 is effected in the device and the contact broken between the cap 28 and the contact members 52, 52. Thus, an open power supply circuit occurs and engine shut-off results in an automatic and efficient manner. If the predetermined angle of tilt is established so that shut-off will occur as in FIG. 2, prior to tipping of the vehicle, then the vehicle need merely be moved toa more level condition of terrain and restarted, the plunger 26 being thus moved upwardly to its operative position. When the engine tilt device is employed merely to terminate engine operation subsequent to tipping, the vehicle must, of course, be righted, care being taken to prop erly slide the plunger 26 upwardly and to properly position the drag member 44 for subsequent operation.
1. An engine tilt shut-off device comprising:
a housing of electrically non-conductive material adapted for mounting approximately centrally on a vehicle and having a lower portion thereof exposed downwardly;
a linearly movable drag member depending from said lower portion of said housing and engaging at its lower end portion the surface beneath the vehicle;
a vertically and linearly slidable member supported within said housing and connected with and carrying said drag member;
resilient means connected between said housing and slidable member and urging said vertically slidable member downwardly whereby to maintain said lower end portion of said drag member in engagement with said subadjacent surface;
said slidable member having an upper and operative position and being urged downwardly therefrom by said resilient means to inoperative positions when the vehicle carrying the device is tilted beyond a predetermined angle causing a release of upward pressure by said subadjacent surface against said drag member;
and electrically conductive means connected with an engine electrical power supply circuit and with said vertically slidable member, said slidable member and conductive means serving cooperatively to close and open said circuit respectively in said upper position and said lower positions of said member whereby automatically to effect engine shut-off operation in response to said predeter mined angle of vehicle tilt.
2. An engine tilt shut'off device as set forth in claim 1 wherein;
said electrically conductive means comprises at least a portion of said vertically slidable member and first and second stationary contact means connected is said engine power supply circuit,
said electrically conductive portion of said slidable member serving to complete a circuit between said contact means with said slidable member in its upper and operative position and said circuit being opened on movement downwardly to said inoperative positions of said slidable member. 3. An engine tilt shut-off device as set forth in claim 2 wherein;
said first and second contact members comprise spring metal members resiliently and frictionally engaging said vertically slidable member. 4. An engine tilt shut-off device as set forth in claim 3 wherein;
said spring metal members take a generally C-shape in cross section with their body portions disposed toward said vertically slidable member and in flexed engagement therewith. 5. An engine tilt shut-off device as set forth in claim 4 wherein;
said vertically slidable member comprises a body portion and a cap portion; the latter of which is electrically conductive and engagable with said contact members as aforesaid. 6. An engine tilt shut-off device as set forth in claim 5 wherein;
said resilient means comprises a coil spring disposed above said slidable member in said housing and urging the same downwardly, said spring diameter being somewhat less than the space between said Contact members. 7. An engine tilt shut-off device as set forth in claim 6 wherein;
said C-shaped contact members have first and second terminal members associated therewith and respectively clamping free end portions of the C-shaped members against said housing. 8. An engine tilt shut-off device as set forth in claim 7 wherein;
said portions of said housing adjacent said terminal members are constructed of electrically insulating material. 9. An engine tilt shut-off device as set forth in claim 8 wherein;
said first and second terminals extend outwardly through said insulating material for connection with said power supply circuit. 10. An engine tilt shut-off device as set forth in claim 9 wherein;
said drag member takes a generally J-shaped configuration at its lower end portion with the longer leg thereof extending upwardly for connection with said sliding member.