Page:Popular Science Monthly Volume 91.djvu/52

This page needs to be proofread.


Measuring Motor-Truck Loads Automatically

��A dial registers the readings from all four wheels as the load is distributed

OVERLOADING of motor trucks would be entirely eliminated if all such trucks were fit-ted with the novel load- measuring device shown in the accompany- ing illustrations. The apparatus makes use of the relative motion between the axles and springs of a vehicle as loads are applied. The varying deflection of springs for loads of dif- ferent weights is allowed for by calibrating the dial scale on which the loads are read.

The device differs from most others of its kind in that the weight carried on each wheel is recorded on the dial as the load is distributed, and not only that on the rear wheels. The proportions of weight over the truck body must be the same as when the device was calibrated or else the read- ing will not be a true. one. This makes it possible for the load to be properly dis- tributed over each wheel.

The readings are obtained through the use of four verti- cal racks, each carried rigidly on a strap round each axle near the ends, the rack re- volving a spur gear mounted on the frame and driving a longitudinal shaft inside the frame channel through a

Detail, of the rack which revolves the spur-gear mounted on the frame

���r^n

����Overloading is one of the greatest dangers which the motor-truck owner fears. It is a question of correct weight distribution

bevel-gear unit. The revolution of the shaft is transmitted to the reading dial placed on the dashboard of the truck in sight of the driver by means of a flexible shaft.

As the load is put on the truck, that portion supported by each wheel forces the spring carrying that wheel down and causes the spur gear on the frame to revolve about the rack nearest that spring, simultaneously turning the 'corresponding longitudinal shaft and the flexible shaft registering the relative motion between the spring and the axle on the reading dial. The weights carried on the other three wheels are registered in a similar manner.

The registering dial is a clever piece of mechanism which consists of a cylindri- cal casing with a central fixed stud carrying loosely four gears of like diameter

VERTICAL RACK BEVEL GEAR. \ AXLE STRAP

��BEVEL GEAR

LONGITUDINAL DIAL DRIVE SHAFT

k

��FLEXIBLE SHAFT 1

���J-TT

��a

��LONGITUDINAL DIAL DRIVE SHAFT ) BEVEL GEAR

��-^o^

��6EVEL GEAR I AXLE STRAP

VERTICAL RACK

��The readings are obtained through four vertical racks, each carried rigidly on a strap round each axle near the ends and each revolving a spur gear driving a shaft through a bevel-gear unit

36

�� �