Mechanical Aids

Description	Breaker, Road, Electric (Kango)
Manufacturer	Kango
Model	Type H
Type	Road breaker
Use
Fleet Number
Date of picture	1961

Electric Roadbreaker
The electric roadbreaker consists of a power unit fitted in a robust light-alloy die-cast casing. An alloy-steel tool-holder is fitted to the casing, and into this may be inserted various boring, breaking, digging or punning accessories. A handle is provided on each side of the upper casing to support the tool.

The roadbreaker is powered by a universal motor that drives a crank disk through a bevel pinion fitted directly on the extended armature-shaft; the crank disk has a crank pin to which a connecting rod and piston are fitted.

The rotation of the crank disk causes the piston to reciprocate inside a cylinder. The cylinder is closed at one end, and the movement of the piston sets up cycles of low and high pressure in the air trapped in the cylinder. The cylinder is allowed some limited movement under
the influence of these pressure cycles, and at each compression it is driven into contact with a striker, thus imparting a blow to the tool bit inserted in the tool holder. 

The striking rate is 900 blows/min and the average work of each blow is 50 ft lb.

The air trapped in the cylinder isolates the percussive mechanism from the electrical components; this imparts a long life to the electric motor, which is further protected by "potting" the armature in resin.  The roadbreaker is lubricated by the automatic circulation of oil from a sump in the foot of the tool to all important parts of the mechanism through a system of oilways.

The range of accessories provided with the tool includes points, chisels, a macadam-cutter for opening road surfaces, a digging spade, and a rectangular "walking rammer" for consolidating backfill.  The operation of the roadbreaker, which weighs 77lb and is rated at 1·5kW, is controlled by a non-locking switch located in one handle.