with sufficient capacity to take care of the momentum of the machine when traveling at full speed, plus the full power of the motor.

12 The motor of this machine is specially designed. In the first machine it was armature controlled; in the last four, field controlled. The lower part of the machine (Fig. 3) is an oil chamber which is filled with oil to a point just below the horizontal shafts. All parts of the machine are automatically lubricated with the exception of the upper bearing and the idler; these are supplied with grease cups and require attention about once a week. This chamber being filled with oil, the rotation of the worm wheels and worm lubricate every part of it perfectly, including the bearings of the horizontal shafts. The first machine ran 2 years on the first charge of oil without attention. The last four machines have now been in nearly two years without changing the oil, and the total bill of expense for lubrication is $6.

13 The service of this machine is shown by a test made on the first one, when doing regular business and running express, stopping at five out of nine floors. The car made 547 round trips in 540 minutes. The life of the cables is unusually long as shown by the record of the first machine. After five years service and making 25 000 car miles, they are still in good condition and it is the opinion of the inspectors that they are good for 50 per cent more service. The design and construction of this machine are such as to make it most reliable and durable and thus eliminate repairs. After 25 000 miles of car travel the racks have not worn out all the tools marks, and the teeth of the phosphor bronze worm wheels are hardly polished all the way across their face. The total bill for repairs for the four machines (Fig. 4) for one year was $318. This includes everything pertaining to the elevators. Of this amount only $83 was spent on the machine proper; $43 was spent for repairing an armature that was damaged by a wire band becoming loose at night, leaving $40 as the total repair bill on four machines for a year, or $10 per year per elevator, the balance being spent on the cars, signal gates, controllers, etc.

14 The great feature of this machine is its safety, which should be the first consideration in any elevator. Automatic stops are placed at both ends of travel of the machine which slow down the machine, cut off the current and set the brake, in case the operator fails to do so, and if the machine goes beyond this point it trips the main circuit breaker and cuts off the current from both controller and machine and beyond this again are the buffers, or mechanical stops, which are sufficient to take care of the machine in case the operator and all automatics fail. It is evident from this arrangement that the

car can never be jerked into the overhead work and pull the cables out of the car, as has often happened in other types of elevators; neither can it be dropped into the basement and the counter weights pulled down upon the car, a most common and serious accident in other elevators. A greater strain can never be put upon these cables than the load in the car. A push button is placed in the car whereby the main circuit breaker can be instantly tripped by the operator, shutting off the current. from both the controller and machine. This is for use in case of disarrangement of the car box of the controller. This principle of the machine and these arrangements make it the safest electric elevator in existence. All the parts of these machines

N

Π

FIG. 5 BED PLATE AND LOWER BUFFER

are accessible when the machines are at the lower end of travel and are easily and quickly taken apart and put together.

15 I have recently made some improvements in the first machine, changing its old spring buffers to oil buffers, and I find the oil buffers are a decided improvement over the pneumatic, as they have a greater capacity and no recoil, the objectionable feature of the pneumatic buffer. The speed of the machines I have already installed, range from 540 to 600 feet per minute, but a much greater speed can be given, if desired, and safely controlled. In the case of very high office buildings, such as are being erected in New York I could safely give them a speed of a thousand feet per minute. This elevator is