Safety grounding circuits

• US 3,969,875 A
• Filed: 04/18/1975
• Issued: 07/20/1976
• Est. Priority Date: 04/18/1975
• Status: Expired due to Term

• Current Assignee: Mtd Products Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: Mtd Products Incorporated (Stanley Black & Decker, Inc.)
• Inventors: Nofel, Thomas J.
• Primary Examiner(s): Mancene, Louis G.
• Assistant Examiner(s): Eskovitz, J. N.
• Application Number:
  US05/569,561
• Time in Patent Office: 459 Days
• Field of Search: 56/10.2, 56/10.5, 56/17.4, 56/320.2, 56/DIG. 15, 56/202, 180/82 R, 192/.046, 192/.098, 192/129 R, 192/129 A
• US Class Current: 56/10.20R
• 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
• CPC Class Codes: B60K 28/00 Safety devices for propulsion-unit control, specially adapted for, or arranged in, vehicles, e.g. preventing fuel supply or ignition in the event of potentially dangerous conditions for electrically-propelled vehicles B60L3/00; road vehicle drive control systems for purposes not related to the control of a particular sub-unit B60W30/00; drive control systems specially adapted for autonomous road vehicles B60W60/00
• CPC Class Codes: Y10S 56/15 Condition responsive

Abstract

An electrical grounding system for grounding the ignition system of an internal combustion engine on a tractor or the like to prevent the starting of the engine and to stop the engine when operating unless switches of the grounding system are so set by operating conditions and positions of parts of the tractor or the like. The grounding system is arranged so that unless switches in an electrical circuit of the grounding system are set or maintained in proper position by operations of the tractor or the like, (such as the clutch of a grass cutting unit carried by the tractor or the like, such as the clutch of the drive mechanism of the tractor or the like, such as by the occupancy or non-occupancy of the seat of the tractor or the like, or such as the connection or dis-connection of a grass catcher to the tractor or the like) the ignition system of the engine is grounded or short circuited and the engine is inoperative.

Claims

1. In an electrical system for controlling a function of a grass mower driven by an internal combustion engine having a magneto which if grounded stops the operation of the engine, said mower having a grass cutting unit powered by said engine, a clutch for engaging and disengaging the cutting unit with the engine, and a catcher carried by the mower for catching cut grass discharged therefrom when the catcher is in proper grass catching position on the mower, the combination of an electrical switch normally closed when the said clutch is engaged and disposed to be automatically opened upon the disengagement of said clutch, a second electrical switch normally closed when the said catcher is not in its proper grass catching position on the mower and disposed to be automatically opened upon the movement of said catcher to a location where it is at its said proper grass catching position, and electrical circuit means electrically connecting said magneto, said switches and ground to connect the magneto with ground to stop the engine upon the closing of said second switch when the catcher is not in said proper grass catching position unless the said first switch is then open upon the disengagement of said clutch to disconnect the magneto with ground.

2. The electrical system claimed in claim 1 and in which said second switch is a reed switch carried by the mower and said catcher includes a magnet positioned to actuate the reed switch to open position upon the movement of the catcher carrying said magnet to such a position relative to the mower that the magnet influences the reed switch.

3. In an electrical system for controlling functions of a grass mower driven by an internal combustion engine having a magneto which if grounded stops the operation of the engine, said mower having a drive mechanism for moving the mower powered by said engine and having a grass cutting unit powered by said engine, the said mower having a first clutch for engaging and disengaging the cutting unit with the engine, a second clutch for engaging the disengaging the said drive mechanism with said engine, a recoil starting mechanism including a handle for starting the engine upon pulling of the handle in a first direction and locking means for manually locking the handle in fixed position against movement in said first direction, and a catcher carried by the mower for catching cut grass discharged therefrom when the catcher is in proper grass catching position on the mower, the combination of a first electrical switch normally closed when the said first clutch is engaged and disposed to be automatically opened upon the disengagement of said first clutch, a second electrical switch normally closed when the second clutch is closed and disposed to be opened upon the disengagement of said second clutch, a third electrical switch normally closed when the said catcher is not in its proper grass catching position on the mower and disposed to be automatically opened upon the movement of said catcher to a location where it is at its proper grass catching position, a fourth electrical switch normally open when the said handle is locked in said fixed position and disposed to be automatically closed upon said handle being unlocked from said fixed position, and first electrical circuit means electrically connecting said magneto, said first and third switches and ground to stop the engine upon the closing of said third switch when the catcher is not in said proper position unless the said first switch is then open, and second electrical circuit means electrically connecting said magneto, said first, second and fourth switches and ground to stop the engine upon the closing either of said first and second switches unless said fourth switch is then in open position.

4. The electrical system claimed in claim 3 wherein the mower has a seat adapted to be occupied by an operator of the mower and movable between a first position when occupied and a second position when not occupied, and including a fifth electrical switch normally open when the seat is in said first position and disposed to be automatically closed when the seat is in second position, and third electrical circuit means electrically connecting said magneto, said first, second and fifth switches and ground to stop the engine upon the closing of said fifth switch unless said first and second switches are then in open position.

5. The electrical system claimed in claim 4 and in which said first, second and third electrical circuit means connects all said first, second, third, fourth and fifth electrical switches to ground unless said first, second and fifth switches are then in open position.

6. In a grass mower having a cutting unit and a grass catcher, an electrical safety grounding system comprising electrical circuit adapted to be connected to the ground and to an electrical ignition system of an internal combustion engine of the mower, switch means normally open to break the connection between ground and said ignition system, first means for operating the switch means in accordance with the clutched or unclutched condition of the cutting unit, and second means for operating the switch means in accordance with the connected or unconnected condition of the grass catcher, said switch means being operated to make electrical connection between ground and said electrical ignition system by the switch means being operated by said second means upon the said grass catcher being in unconnected condition, unless the switch means is operated by said first means upon the cutting unit being in unclutched condition.

7. The grounding system claimed in claim 6 and including third means for operating the switch means in accordance with the clutched or unclutched condition of a drive mechanism of the mower, and in which the switch means is operated to make electrical connection between ground and said electrical ignition system by the switch means being operated by said third means upon said drive mechanism being in clutched position.

8. In a grass mower having an internal combustion engine with an electrical ignition system for the same, the mower having a cutting unit adapted to be put in clutched and unclutched condition, and having a grass catcher movable to a first position to collect cut grass blown from said cutting unit and to a second position varied from said first position relative to said mower, the combination of first electrical switch operable in accordance with the clutched and unclutched condition of the cutting unit, a second electrical switch operable in accordance with the position of said grass catcher, and electrical circuit means interconnecting said switches, said ignition system and ground to short circuit the said ignition system upon said grass catcher being moved from said first position unless said cutting unit is in unclutched position.

9. In a grass mower having an internal combustion engine with an electrical ignition system for the same, the mower having a cutter unit adapted to be put in clutched and unclutched condition, the mower having a seat adapted to move to be in one position when occupied and to move to be in a second position when unoccupied, the mower having a drive transmission adapted to be put in clutched and unclutched position, first switch means positioned to be actuated in accordance with the clutched and unclutched condition of the cutter unit, second switch means positioned to be actuated in accordance with the location of the seat in said first and second positions, and third switch means positioned to be actuated in accordance with the clutched and unclutched condition of the drive transmission, and electrical circuit means electrically connecting said switches, said ignition system and ground to short circuit the ignition system and stop the engine when said seat is in unoccupied position unless said cutter unit and said drive transmission are in unclutched conditions.