The Lambert friction gearing disk drive transmission was invented by John William Lambert originally in 1904. The invention relates to a friction disk drive transmission for automobiles that is gearless. He saw the need for a simple transmission of engine power to an automobile's drive wheels.
The main or driving disk is faced with a disk of aluminum. The driven disk has a working rim of elastic fiber. Lambert says in the invention, In practice I have found that this combination of aluminum and fiber bearing surfaces gives the maximum degree of friction and durability, thereby especially adapting the gearing for use on motor vehicles of the heavier kind, where the friction surfaces are at times subjected to great strains, and must, therefore, have a frictional contact of a high degree of efficiency in order to avoid slipping. It will be observed that the aluminum is advantageous also, because it will not tarnish or rust appreciably, but will always present a smooth, clean surface to the fiber periphery, so that wear will be reduced to a minimum.
The friction disk drive was one of the key features of the Union automobile and Lambert automobile. Lambert started making the friction disk and traversing pinion drive in 1900. The first attempt was with a leather faced disk and an iron friction wheel. It had an eighteen inch diameter with a one and a half inch face. With this first attempt the leather was charred within the first three miles (5 km) of running it. The disk was then made with a wood fiber about a half inch thick. The material had a glossy surface and worked fine for a while, however it broke up after only 200 to 300 miles (480 km) run. Lambert then conducted various experiments on the friction disk to get better performance. In one experiment a cone of cast aluminum was used as one member of a level friction drive with excellent results. Lambert then realizing that the pull was due to the aluminum itself, a disk was faced with it and the traversing wheel with strawboard. This accidental discovery made Lambert automobiles more successful than other cars that attempted at friction driving.
The aluminum disk was twenty-two inches in diameter and was faced with an aluminum disk of equal size with a facing of just over a quarter of an inch in thickness. The traversing wheel was eighteen inches in diameter with a 1.5-inch (38 mm) working face, strawboard rings eighteen inches outside diameter by three inches radial dimension. It was clamped between cast iron members supporting the strawboard rings inside and clamping them sideways. This fibrous friction wheel is splined to slide on a sleeve seventeen inches in diameter variably carried on a steel shaft thirteen inches in diameter. It journaled in swinging boxes so that the wheel can be pressed against or separated from the iron, aluminum-faced driving disk, which is motor driven.
The speed regulation was done by a steel bell crank, forked and carrying a U-shaped shoe to engage the grooved hub on the driving wheel at one end, and having the other end linked to the speed change and reversing lever. The wheel slid freely on the sleeve when moved away from the disk. All the speeds, from the highest to the lowest, could be done in either direction. The Lambert transmission always used side chains to the rear wheels and a balance gear connected to the splined sleeve on which the wheel slide and a steel shaft which supported the sleeve. The key feature of the Lambert automobile was the friction disk drive carried over from the Union automobile.
Lambert applied for a patent on this transmission which became No. 761,384 finalized May 31, 1904. The patent has six claims:
1. In a power-transmitting mechanism, the combination, of a pair of shafts, a friction-disk carried by each shaft, one disk having a bearing part of aluminium and the other a fiber part bearing upon said aluminium bearing part.
2. In power-transmitting mechanism, the combination of a drive-shaft and a driven shaft, a friction-disk carried by each shaft, the face of one disk being provided with an aluminium bearing-plate detachably secured thereto and the attaching means being outside of the usual working area of the bearing-plate against which the periphery of the other disk bears.
3. In a power-transmitting, mechanism, the combination of a driving-shaft, a friction-disk on said shaft bearing a face of aluminium, and a driven shaft carrying a friction-disk, a fiber periphery secured to said disk and adapted to bear on the aluminium face of the driving-disk.
4. In a power-transmitting mechanism, the combination with a driving-shaft, a friction-disk carried thereby, a bearing-plate of aluminium for said disk, means for detachably securing said aluminium plate to the face of said driving-disk, a driven shaft, the means for attaching the aluminium plate to the driving-disk being outside of the usual working area of the disk, a disk mounted thereon, a fiber periphery secured to said disk and adapted to bear on the aluminium face of said driving-disk.
5. In a friction-transmitting mechanism, a wheel having a frictional surface of aluminium.
6. In a frictional gearing, the combination with a friction-disk having a surface of aluminium, of a transmitting-disk having an elastic frictional surface bearing upon said aluminium surface.
The improved 1910 invention, patent No. 954,977, made additional improvements to the original friction driving mechanism and had the following claims:
1. Power transmission mechanism including a power transmitting wheel, rigid pins projecting from the side thereof parallel with the axis of the wheel; a longitudinally movable shaft independent of and coaxial with said wheel, rigid arms projecting radially from said shaft near said wheel and provided with ball sockets, balls fitting in said sockets so as to be slidable on said pins, and means insertible in each socket for tightening the ball therein, whereby said shaft may have longitudinal movement and the parts have no angular play.
2. Friction power transmission mechanism including a power transmitting wheel, a longitudinally movable shaft independent of and coaxial with said wheel, rigid pins projecting from the side of said wheel, rigid arms extending radially from said shaft near said wheel with their outer ends apertured and split, one end of the apertured portion of each arm being contracted and having a concave bearing surface, a ball adapted to fit in the aperture of each arm against said bearing surface and surrounding said pin so as to be slidable thereon, a tubular plug screwed into each arm with a concave bearing surface on the inner end to engage said ball, and means for clamping the split end of each arm.