GB Patent: GB-110,325
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| Improvements in Machine Tools employing Worm Gearing for Dividing Purposes
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Patentees:
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| James H. Melloy (exact or similar names) - Manchester, Lancaster County, England |
| Willie Owen (exact or similar names) - Manchester, Lancaster County, England |
| Manufacturer: |
| Not known to have been produced |
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Patent Dates:
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| Applied: |
Jun. 16, 1917 |
| Granted: |
Oct. 18, 1917 |
Espacenet patent
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Joel Havens
"Vintage Machinery" entry for William Muir & Co.
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Description: |
| Abstract:
Gear-cutting; backlash, preventing.-Means are provided for compensating for wear and preventing back-lash in the worm-gearing driving the work-tables in machines for cutting toothed gears and in other machines employing worm gearing for dividing purposes. The invention is shown as applied to a bobbing-machine such as is described in Specification 6595/11, in which the work is carried on a table rotated by a worm-wheel b driven by a worm d. The worm spindle is carried in a cradle n of semi-circular cross-section which is secured at p into a bracket a carried on the machine-bed. A lever r pivoted in the bracket a has an arm passing through an opening in the cradle n and bearing on the working surface of the worm d under the pull of a spring s. The other end of the lever r carries a contact point which as shown is just clear of a fixed point v. As the worm rotates, the lever swings through the angle shown by the dotted lines, and on the completion of one revolution, a gap t in the worm allows the lever to return to the position shown. When the worm shows appreciable wear, the position of swing of the lever r varies and the contact-points complete an electric circuit and give an audible or other signal. The attendant can then, by means of a hand-wheel z and wormgear, rotate the cradle n and move the worm to the left to compensate for the wear. In a modification, the wear is compensated for automatically by arranging the lever r to vibrate a pawl on a ratchet-wheel in such a position that when the lever vibrates through its normal arc the ratchet-wheel is not moved. When the position of the arc changes owing to wear of the worm, the pawl engages a tooth and rotates the ratchet-wheel and through the gear described above rotates the cradle n. The worm d has one end parallel to the thread and has mounted alongside a similar ended worm-piece c free to move endways on the spindle. The other end of this piece c is severed to taka a nut h which bears against a thrust-washer m and is secured to one end of a coiled spring, the other end of which is secured to the pin r. This spring tends to rotate the nut h so as to push the piece e to the right so that the thread bears on the back of the teeth on the table b and prevents backlash. |
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