SELF-PROPELLED RANDOM MOTION LAWNMOWER

• US 3,698,523 A
• Filed: 10/20/1969
• Issued: 10/17/1972
• Est. Priority Date: 10/20/1969
• Status: Expired due to Term

• Current Assignee: Bellinger S. Lawrence
• Original Assignee: Bellinger S. Lawrence
• Inventors: Bellinger, S. Lawrence
• Primary Examiner(s): Wyche, Benjamin W.
• Assistant Examiner(s): Heald, Randall
• Application Number:
  US04/870,714
• Time in Patent Office: 1,093 Days
• Field of Search: 192/12BA,35,36,26,81R
• US Class Current: 192/12.0BA
• CPC Class Codes: A01D 2101/00 Lawn-mowers
• CPC Class Codes: A01D 34/008 for automated or remotely controlled operation
• CPC Class Codes: A01D 69/02 electric
• CPC Class Codes: A01D 69/08 Clutches
• CPC Class Codes: G05D 1/0265 using buried wires

Abstract

Disclosed is a self-propelled lawnmower for cutting grass in a completely random and unattended manner. The unit is preferably propelled by a battery and comprises a frame supported on a pair of front caster wheels and a pair of rear drive wheels. The drive wheels are coupled to a continuously rotating drive shaft by individual clutch-brake mechanisms. When a boundary wire is sensed by coils on the frame, the drive wheel furthest away from the broader is unclutched and braked to pivot or turn the mower. No backup motor or complex steering control is required. A pair of adjustable rotary cutter blade assemblies are carried on the frame.

Claims

1. A combination clutch-brake comprising rotatable driving and driven members, a helical coil spring surrounding said members and coupling said driving member to said driven member, a metal band secured to the drive end of said spring, the opposite end of said spring being secured to said driven member, a pivoted lever, a coil and core mounted on said lever, said core including means for frictionally engaging said band and means for energizing said coil to pivot said lever and cause said core to engage and stop said band whereby said spring expands and releases said driving member and brakes said driven member.

2. Apparatus according to claim 1 including a pair of levers, coils and cores on opposite sides of said band.

3. Apparatus according to claim 1 wherein said core and coil are pivoted to said lever.

4. Apparatus according to claim 1 including a spring biasing said lever, coil and core away from said band.