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Title: |
1879 article - Improved spring for scroll saws |
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Source: |
Manufacturer and builder / Volume 11, Issue 9; September 1879; p. 196 |
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Insert Date: |
11/29/2023 10:58:43 AM |
Here is the text of the article:
One of the reasons why scroll saws are sometimes unexpectedly fractured is that the spring pulling them upward is not as quickly acting as it should be, caused by its having too much weight and momentum, which always retards all rapid to-and-fro motions. In the spring represented in the adjoined engraving this defect has been successfully obviated, and the result is a spring which cannot only be applied to jig saws, but to any machine requiring a very quickly acting spring, adjustable to various degrees of tension, and adapted to any size of saw blade. The maker claims that with its use an inferior machine can be made to work well, which is an important fact, as there are many inferior machines in use, which may all be improved by the substitution of this spring in place of the inferior one that renders many of these machines almost worthless, as it is impossible to run them at a great speed without danger of breaking the saw blades. It is claimed for this spring that a scroll saw can be run with it at the rate of 1,000 strokes per minute without the least risk. We therefore advise all who contemplate buying a new jig saw because they are not satisfied with what they have, to try this spring, and attach it to their machine.
In our engraving, the top A is attached to the stand above the table by means of wood screws; this part is slotted for adjustment to the height of the stroke, so as to allow for different lengths of saws. B B are wooden arms, supporting the strap D, to which the saw is at- tached by means of the hook F; the top of the strap D has two hooks lapping over the arms B B, which turn on pivots at their outer ends, and rest at G G upon wooden springs E E. The latter rest on fulcrums or bridges, affording a leverage which gives an easy motion to the springs. The movements of these springs are very slight, not over 1/4 of an inch to the full stroke of the saw, showing that it is quite safe to run the machine at a very high speed. The strength and stiffness of these springs are regulated by the thumb screws I I, by which they can be easily adjusted to the tension required.
This spring is manufactured by I. R. Joslin, of 91 Liberty street, New York, to whom we are indebted for this illustration. |
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