New Fire Extinguisher Wheels
A built-up steel wheel with grooved convex tires is the latest development in wheels for fire extinguishers. They are made by French & Hecht of Davenport, Iowa, and Springfield, Ohio.
The illustration shows in a general way the steel spoke wheel with a steel hub which has a cast iron bearing box. The wheel illustrated is fifty inches in diameter with spokes 9/16 inch in diameter. The tire is grooved convex 2 1/2 inch wide and 1/4 inch thick. As the wheel rolls on the pavement, the spoke ends of the spokes do not come in contact so that the wheel rolls smoothly without any vibration.
The wheels have monogramed caps over the ends of the hubs with the name of the extinguisher manufacturer placed thereon. These wheels are being furnished in various diameters. T h e approximate same general design applies to wheels with diameters as small as sixteen inches. The wheels illustrated apply to a 40-gallon extinguisher.
Other typical wheels are the 30-inch diameter with grooved convex tires for smaller extinguishers. The 16-inch diameter for 10-20 gallon extinguisher and the 24-inch wheel with 1 3/8-inch wide channel tire. These dimensions give the reader somewhat of a picture of the specific size of wheel as produced for such use.
In a general way the design of these steel built wheels is such that the spokes at the hubs are arranged in a staggered position. In the wheel, as shown, the two rows of spokes at the hub are three incites apart but at the rim the spokes come on a straight line.
A distinctive feature of these wheels is the fastening of the spokes at the hub and tire. The steel spokes are forged while hot into the hub and have the heads formed on the inside of the hub and shoulders on the outside. This produces a spoke fastening similar to that of a boiler rivet. The spokes are firmly headed and shouldered into the tire and as they are in a trussed position (not straight) a wheel is produced that is light in weight, yet very strong and sturdy.
Added strength without excessive weight, always an important consideration in wheel design, is gained by the light weight tire having the groove in the middle and the tire convex. The grooves give additional stiffness to the tire, and as has been pointed out provide protection for the spoke heads and for the floors. This general type of wheel has been in use by a number of fire extinguisher manufacturers for a number of years, proving eminently satisfactory.