The drum machine was particular adapted to the short travel lift such as this undercounter underslung dumbwaiter. The drum could accommodate the small length of wire rope required and the light capacity of the car might well eliminate the need for a counterweight and accompanying wire rope to drum.

Graphic source: Der Aufzugbau

"Because of the usual unsatisfactory results obtained with hydraulic power, The Kerscher Elevator Co. has developed the electric cradle lift type elevator. The major difficulties of the hydraulic elevator, operating from an outside water supply, is the difficulty of eliminating leakage at the valves and packing glands, and the freezing of water in the winter. Should the water contain sand or other abrasive materials, the valves and packing are soon leaking. This causes the elevator to "creep" which is dangerous and makes positive control difficult. Freezing results in an expensive thawing out repair bill. Where the hydraulic type is operated by a pump, excessive noises often result. The electric cradle lift type
has been developed to eliminate these disadvantages of the hydraulic type. These elevators are designed for capacities ranging from several hundred pounds to 6,000 pounds, and speeds ranging from 20 to 60 feet per minute. The control may be Constant Pressure or Full Automatic."

Graphic Source: Kerscher Catalog

Edmonds Elevator (U.S.), back-gear drive machine with drum for hoist and counterweight cables.

Graphic Source: Edmonds Elevator Company Catalog

Worm and gear driving drum. Hand rope control

Graphic Source: Carl Flohr

Early spur gear machine drive drum. Notice the bevel gear

Graphic Source: Carl Flohr

The Morse-Williams elevator displayed at the Chicago exhibition of 1898 was an example of the electric elevator in its earliest commercial form, with the motor connected directly to the load. By this time, incandescent lighting circuits in large cities were sufficiently extensive to make such installations practical. However, capacity and speed were limited by weaknesses of the control system and the necessity of using a drum.

Graphic Source: Going Up

Otis Drum Machine with varying rating. The No. 4 D.S. machine is arranged to take three different size motors as mentioned in the duty tables, viz: No. 15, 20-A and No. 20. The duties range from 45 feet to 80 feet speed and loads of 5,500 lbs. to 10,000 lbs. for the internal gear machine. For the straight machine, the duties range form 4,500 lbs. at 100-ft. speed to 2,000 lb. at 250 ft. speed with the no. 15 motor. The machine with no. 20 motor has duties ranging from 5,000 lbs. at 150-ft. speed to 3,000 lbs. at 250 ft. speed.

Graphic Source: Otis Indicator November 1911

With the No. 4 D.S.A.C. Machines an arrangement of back gears can be provided for use when heavy safes are to be hoisted in office buildings. These gears are made for two ratios of speed reduction, 4:1, for use when the car speed with ordinary loading does not exceed 200 feet per minute, and 9:1, for speeds above 200 ft. per minute. The back gears are mounted on a shaft which runs in sliding boxes supported on stands bolted to the bed plate on the side of the machine next to the drum. A pinion on the rotor shaft drives the first back gear and a pinion on the back gear shaft drives a gear on the worm shaft. When these back gears are not required, the shaft and boxes are moved to the extreme outward position, disengaging the gears. The boxes are held rigidly in position by pins. When a safe is to be lifted, the sleeve coupling between the rotor shaft and worm shaft is removed and the back gears moved up into mesh.

Graphic Source: Otis Indicator December 1911

Two views of Stigler drum machine. Note wheel for lowering in event of power failure.

Graphic Source: Raffronto fra le norme vigenti sugli

Without too much change in reduction gearing and control equipment was adaptable to overhead or floor installation. Note termination holes in near each rim of the drum. While hoist cables wound from the center outward the counterweight cables were winding inward in the other direction. Pressure on the drum and bearings was maintained as evenly as possible. Grooves in the drum assured that cables wond on and off smoothly and orderly.

Graphic Source: Eaton and Prince

The 'Micro-Drive', a self-leveling system for elevators devised by Otis and generally accepted as another fundamental advance in sophisticated elevator technology.

Graphic Source: Going Up

Otis automatic residence drum machines 1912 were used in huge mansions and thus little different from machines used in commercial establishments.

Graphic Source: Otis Indicator January 1912

"This is our latest Direct Coupled Electric Drum elevator machine, built for capacities up to 10,000 lbs., and for both direct and alternating current. It can be used for either freight or passenger work, according to the size of drum and gearing; for car speeds from 45 to 100 ft. per minute for freight work, and for passenger service up to 300 ft. per minute. As with our traction type elevator, it can be used with hand cable, car switch or full automatic push-button control. Owing to the few moving parts, and the simple and efficient safety attachments, it makes a very satisfactory elevator, quiet in operation, and very powerful. In general it is similar to our Traction machine, being equipped with our new electric brake, oil-tight worm gear housing, ball thrust bearings, etc. It is also provided with our improved electric machine terminal switch which does away with all moving levers and small castings, so there is nothing to constantly break as is the case with many machines using a mechanical terminal stop. The machine is equipped with an electric slack cable safety device, which has also enabled doing away with a number of light castings which are easily broken."

Graphic Source: Salem Elevator Works of Salem, Massachusetts, founded in 1862.

Schematic of Direct-Drive Drum Electric push-button elevator engine manufactured by The Winslow Elevator & Machine Co., Chicago, Illinois in 1903.

Early Otis double worm geared and spur geared drum Electric.

Graphic Source: Der Fahrstuhl

London was the first city to develop an underground railway, the Baker street station being opened in May 1863. The New York subway was started in 1868, followed by similar systems in Chicago (1892), Budapest (1896) and Glasgow (1897). By the early 1970s, 35 cities across the world had an underground transport system, with New York carrying the greatest volume of passengers. London's Central Line was opened in 1890. Because of its exceptional depth below the surface - an average of 30 meters - elevators were installed at each station. After the scrutiny of a variety of proposals, the construction company opted for a revolutionary system, the first to be powered by electricity. Forty-eight elevators were ordered from the Sprague Elevator Company of Watessing, New Jersey. These elevators were capable of carrying 100 passengers at a speed of one meter per second, using barely half the energy required by a hydraulic elevator of comparable power. So successful was Sprague's elevator that within four years hydraulic elevators were abandoned, the last being the giant elevator at Shepherd's Bush station installed in 1904. In the following year Sprague joined with Otis to cope with the scale of his commitments; 170 elevators for the new London tube lines, Bakerloo, Northern and Piccadilly in 1906. The majority of these elevators remained in service for 47 years.

Graphic Source: Going Up

In the early 1900's a dumbwaiter specialists Burdett Rowntree manufacturing Co. of Chicago and New york City installed this electric dumbwaiter machine for duties from 100 lbs. at 500 fpm to 500 lbs. at 200 fpm with a variety of automatic controls for banks, office buildings, hospitals and government buildings. Fig. 2 shows a central distributing station.

Graphic Source: Electric Dumbwaiter Service