US Patent: 432,585
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| Screw Cutting Lathe
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Patentee:
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| Ephrem F. Valiquet (exact or similar names) - Norwich, New London County, CT |
| Manufacturer: |
| Not known to have been produced |
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Patent Dates:
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| Applied: |
Apr. 21, 1890 |
| Granted: |
Jul. 22, 1890 |
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Joel Havens
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Description: |
| Frank H. Allen - patent attorney
This invention is in screw-cutting-engine lathes, and has for its object to so improve such lathes by simple and inexpensive changes that much time may be saved in cutting screws of any considerable length. Lathes of this class are commonly provided with a feed-screw, extending parallel with the bed, which is traversed by a nut attached to the tool carriage. In many instances this nut is formed of two companion sections that may be simultaneously brought together to clasp the feed-screw, or may be separated when not using the lathe for screw cutting. As a rule, when cutting a thread in such lathes after having run the tool to the length of the cut, the direction of rotation of the spindle and connected work that is being turned is reversed, and the tool-carriage is slowly carried backward in the same manner in which it was moved forward,that is to say, the nut on the feed-screw traverses the said screw backward until the tool is in a position to take a new cut. This moving of the tool-carriage backward by means of the feed-screw is necessarily a slow process, and my present invention has for its object such improvements as will permit the split nut to be separated and thrown out of engagement with the feed - screw, while the carriage is quickly run back by means of the rack-and pinion feed used in ordinary turning. When the tool is in proper position for a new cut, the split-nut is closed on the feed-screw, which meanwhile has been running continuously in the same direction. If this were attempted in lathes as now commonly made, there would be no certainty that the tool would enter the thread and follow the previous cut, and the chances would be many for spoiling the thread; but with my added improvements the carriage may be run back by hand and the nut closed on the feed-screw with an absolute certainty that the point of the cutting tool will register perfectly with the previous cut. |
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