Image
|
Title: |
1871 Article: Positive-motion scrollsaw |
|
Source: |
Manufacturer & Builder, November 1870 issue. |
|
Insert Date: |
4/22/2003 9:11:10 PM |
Here is the complete text of the article:
POSITIVE-MOTION SCROLL-SAW
We have little need in the present article to describe the disadvantages of the ordinary scroll-saw. What they are is well known to those who have used them. It is sufficient here to show the good points of the invention we illustrate, leaving the description of its merits to convince those who have used saws that it stands among the first upon the list.
The form of the machine, it will be readily seen, is well planned, and gives plenty of room around the table. The saw is held by two cross-heads, running in adjustable iron guide-ways. The eccentric lever E, when pulled forward and down, instantly releases the saw when it is necessary to take it out. A leather strap C, from a balanced crank on the lower driving-shaft A, pulls the saw down, and it is lifted by the balanced crank B on the upper shaft. The rod D connects the saw with the upper slide F. This rod passes through a nut resting on the upper cross-head, and can be screwed up or down to accommodate any length of saw from 10 to 30 inches, and give any desired tension. The two shafts A A are connected by a belt J; but to prevent any slipping from interfering with the relative positions of the cranks B B, the pulley-wheels H H are also connected by the rod I against which the saw is strained. The gate holding the cross-head at the top of the saw can be moved up or down, to accommodate any length of saw, and thrown forward to give the saw any desired rake. A piston-pump just below D gives an air-blast to clear away the sawdust. In case of breaking of a pin, the saw instantly stops; for if it is the upper one that gives out, the leather strap can only pull it down to finish its stroke, but has no power to push whatever; while should the lower one give way, the connecting-rod D pulls the saw to the top of the stroke and leaves it there, since the only motion it can give the saw is an upward one; on the downward stroke it slips through the cross-head, as the nut which holds it only rests upon the upper side of the head.
This machine in its construction and operation is really a gate-saw, having all the advantages of the old-fashioned gate-saw without its disadvantages. In the cut, the saw is represented 4 feet from the post; they can be made, however, any distance from it up to six feet. There is no jar when the saw is running fast - not enough to stir the saw-dust upon the table. Various lengths of saw may be used from 8 to 30 inches, and the saw may be run down to one eighth or even a sixteenth. The machine is guaranteed to run smoothly at 600 or 650 strokes per minute, with five or six-inch stroke.
Small sizes are made that will make from 600 to 800 four-inch strokes per minute without any jar. The machine takes no more room than an ordinary spring-saw, as the upper shaft is placed high enough for a man to pass beneath it without stooping; and can be run equally well from above or below without the use of a centre shaft, by simply placng the driving-pulleys on the upper or lower shaft as occasion may require. The shafts are run in the most improved self-adjusting metal boxes on pivots. The bed or table is made separate from the frame, and is adjustable to suit any rake or slant of the saw, so that the cut is always perpendicular to the surface of the work, no matter what the rake may be. Sawyers will appreciate the advantage this feature gives in cutting out corners.
Having explained the construction and operation of time saw, we may, by way of recapitulation, say the saw is run by direct action upon time two crank-shafts, without the use of a spring or anything of the kind that is liable to get out of order, thereby giving to the saw a perfect positive motion, with an even tension throughout the length of time stroke us great as the saw will bear. It is needless to add that simplicity of construction is of the imighest importance in designing scroll-saws.
Our readers who may desire further information in regard to any points in connection with this machine are referred to the manufacturer, Mr. Henry L. Beach, Montrose, Susquehanna County, Pa. Mr. Beach also has an office at 42 John street, in this city. A large number of these machines are in operation in large wood-working establishments in various parts of the country. Our readers in this vicinity who desire to make a personal inspection of its workings will find one at Mr. T. F. Rowland?s Continental Works, at Green Point, L. I., and at the box-wood establishment of Messrs. Vanderburg & Wells, corner of Fulton and Dutch streets, in this city. |
|
|
|
|