Patent GB-840723-A (GB)
Title: Improvements in or relating to lawn mowers
IPC: A01D43/16
Filed: 1956-06-26
Abstract: 840,723. Edge trimmers. LEGGE, V. T. June 26, 1957 [June 26, 1956; Nov. 30, 1956; Feb. 28, 1957], Nos. 19740/56, 36651/56 and 6689/57. Class 6(2). [Also in Group XXIV] A lawn mower has an edge trimming device which is positively driven from the main cutter shaft either through gears or through a chain and sprocket mechanism. A land roller 14 journalled in side-plates one of which is shown at 11, drives through a chain 15 a cutter cylinder 16 mounted on a shaft 17 and co-operating with an adjustable ledger blade 18. A casing 20 for the edge trimming attachment contains a spur gear 21 keyed to the shaft 17 and smaller spur gears 22-24 permanently meshed with the spur gear 21, the gear 24 being mounted on an auxiliary cutter shaft 25 carrying the edgetrimming cutter 26. The cutter 26 of rotary blade type, cooperates with a ledger blade 31a, Fig. 4, and is protected by a steel plate 32. The casing 20 forms an arm rotatable about the shaft 17 to a position, Fig. 2 (not shown), where the cutter is out of operation. A control 34 raises the cutter 26 by means of a Bowden cable 35, a lever 37 enabling the cutter to be locked out of action. The cable 35 passes through a shaft 42 attached to the side-plate 11, through a rubber stop 47, and is then attached to a cross pin 40 mounted in a slot 61 in a plate 62 which is connected to the casing 20 by a pin 63. A double-sided triangular plate 38, pivoted by shaft 63 on the casing 20, has slots 39 which also carry the pin 40. When the cable 35 is released the movement of the pin 40 in the slots 39 rotates the member 38 anti-clockwise about the shaft 63 to engage its upper ends 64 beneath the shaft 42, so locking the cutter in its operative position. If the cable 35 is pulled, the movement of the pin 40 in the slots 39 rotates the member 38 clockwise about the shaft 63 so releasing the catch from the shaft 42 ; further movement of the cable 35 pulls up the plate 62 thereby raising the casing 20 about the shaft 17 from its position on a stop 33 bolted to the side-plate 11. In a modification the edge trimmer is inside the side-plate 11, the edge cutting blades lying behind one end of the grass-cutter as shown in Fig. 4. In this version the raising and locking means may comprise either a catch lock, Fig. 4, or the device shown in Fig. 10. After passing through the shaft 45 and the rubber stop 47, the cable is connected to a pin 48 one end of which is in a vertical slot 49 in a plate member 50 connected at its lower end by a bolt 51 to the casing 20. The other end of the pin 48 is mounted in a horizontal slot 51a in a latch member 52, the lower end of which extends through an opening 53 in an extension shaft 54 of the gear 22. A stop 55 on the side-plate 11 has a flat surface 57 which acts on the latch member 52 so preventing the casing 20 from being raised about the shaft 17 by the first pull on the cable 35 which moves the pin 48 vertically in the slot 49 and disengages the latch member 52, continued pulling on the cable raising the casing 20 about the shaft 17. A friction clutch may be provided between the shaft 17 and the first spur gear 21, Fig. 12 (not shown). The edge cutter may be downwardly cutting.