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Title: |
1908 ArticleLeBlond, R. K., Machine Tool Co.-Millers |
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Source: |
Southern Machinery, V7, May 1908, pg. 28 |
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Insert Date: |
6/28/2017 1:22:43 PM |
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Fig. 5 shows a milling machine drive, which is same as Fig. 1, but owing to the interference of the over-arm a Morse silent chain is used. Fig. 6 shows another milling machine, the construction of which is essentially the same as in the lathe, but is modified in detail. The drive is through a rawhide gear to the shaft, on which the double friction gears are mounted. These are operated by two levers, one on each side of the machine, and give two changes of speed as well as means for starting and stopping quickly independent of the motor. The intermediate shafts carry two sets of sliding cone gears, which give a total of eighteen changes. For variable speed drive, all of the LeBlond tools require a 3 to 1 speed variation, except the 24-inch high-speed lathe. This company recommends the shunt wound motor with field control. This type of motor will deliver the maximum rated horsepower at all loads, has a good regulation and is operated with practically the same high efficiency irrespective of the speed. The gear ratios from the motor to the tool are proportioned to suit the speed of the motor. For variable speed, the manufacturers recommend the drum type of controller, which is entirely enclosed, compact and the necessary resistance is attached to the bottom or the back. For lathes, except on these with very short beds, the controller is operated with a lever on the lathe apron. For milling machines, the panel type non-reverse controller will be found satisfactory. It is necessary, however, that the controller be so arranged that the motor cannot be started under conditions of weakened field. |
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