USRE393E - Improved method of hanging and straining reciprocating saws - Google Patents

Description

i i l ISAAC N. FORRESTER, OF CENTREVILLE, VIRGINIA.

IMPROVED METHOD 0F HANGING AND STRAlNlNG HECIPROCATING SAWS.

Spccilication forming part of Leiters Patent No. 13,716, dated October 30, 1855; Reissue No. 393, dated September f2, 18.36.

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Be it known that I, Isaac N. Fonansrna, of Centreville, in the county of Fairfax and State of Virginia, have invented and made certain new and usef'ul Improvements in the Manner or Mode of I-Ianging and Arranging Muley and all other Reciprocating Saws for Saw-mills, and which improvements I term the Self-Ran ging Saws;77 and I do hereby declare that the following is a clear, full, and exact description of the same, reference being had to the accompanying drawings, making a part of this speciiication, in which- Figure l is a perspective view or sketch of the framing or superstructure of a saw-mill, asataaac acaaaaandbbbbb; c c cc,the way; d, the adjusting slide-groove 5 e c e e, the guide-block, with saw or play groove g g. j' f is the cap to groove. slides of saw. ltare tightening-pins. .I .I J J are clamps or key-staples. K is the saw; L, the saw-table. m m is the kerf or guide-slot.

Fig. 2 shows the saw-blade detached, with the ears or flanges n n attached to the saw by side pieces or clamps, p 19. This saw-blade shows the application oi" the ranging devices when designed for a single or slabbing saw, as in Fig. 1.

F10; 3 shows a gang or series of saw-blades arranged to the framing and ways, and the cross-heads.

Fig. 4 shows one of the gang-saws detached.

Deeming it unnecessary to describe in full the general construction of saw-mills, as I do not comprehend herein any claim thereto, I

will therefore confine myself vto the description of the principle of my improvements and the object attained thereby.

It is a well-known fact that in the very numerous improvements in saw-mills, as well as in the various alleged improved modes of hanging saws, the aim has been to so arrange the hanging of the saw or straining of the blade that in the cutting of the log or timber the saw-blade should not leave the log or cut with irregularity, or deflect from the direct or parallel position relative 'to the log, or to incline or tend toward the sides of the carriage, whereby the korf or track of the saw would not be out of a true line. These defects and difficulties in hanging saws have been more or less consequent upon the applih is a slot for oilingY cation ot' the various modes resorted to heretofore, and consequentlytheoperation of sawing has been attended with much defective timber and considerable loss of lumber.

vIn applying my mode of hanging sawsl to gang-mills various important results ensue, as

hanging saws so as to accomplish the desired' purpose. Y

I have tested and proved the fact that the undue strain or rigidity of the saw-blades throughout their extent of surface has been the l sole cause of the very great dii'iiculties mentioned. In all other modes of hanging saws than mine the ends ofthe saws have been buckled or strained so stiff and rigid by the application of clamps or lateral pieces that the back edges of the blades possess as much rigidity as does the teeth part, the tendency ef which is to make the blades of the saws wind, or become more or less twisted if becorning heated, through the rapid action and abrasion or rubbing of the surfaces of the blades against the timber. Thus it not unfrequently occurs that in commencing on the side of a log with a single saw the blade has a tendency to deect outward, owing to the action of the plank part of the log lopping l or striking against the saw-surface, owing to the vibratory action of the detached part of log,which plays more or less, and more on one side of the blade. Especially does this action ensue when blades, as ordinarily hung, encounter knotty or tough portions of thetimber, thus heating, expanding, and twisting the blades, and springing or winding out oittrue, and not unfrequently stretching or elongating as to be rendered almost useless for sawing purposes. Vihen such causes operate, the cut or kerf of the saw is irregular and rough, owing to the binding of portions of the blades, and under no circumstance whatever, when such causes exist, can even, smooth, and good lumber be produced, but instead the surface of the lumber will indicate every.rake or cui; of the blade. The action of my saws appears to be somewhat similar tothe action of the pressure of water on a vessels rudder, or as the curved lateral motion of aishs tail gives direction to the shs body or its head. Wherever there is a bend, spring, or twist of the blade part, and no matter how small, such irregular surface tends to control or act upon the course or direction of the teeth. These difficulties, however, cannot occur in my mode of hanging saws, as I do not strain the ends there of nor stiffen the surface of the blade; but the nature and principle of my improvements ccnsist in arranging a single muley slabbing sawblade in the following manner, viz: I take an ordinary mill-saw blade and attach to one end thereof, on the front or teeth part or cuttingcdge, flanges or ear guide-pieces a a, Fig. 2, riveted to thesaw-blade, as at p p, when a slabbing or single blade is used, or by employing clamp flange-plates g2g, as at Fig. fl. The ears n n, Fig. 2, of a muley slabbingblade are attached so as to allow the point or line of connection to be in a vertical line with the base of the teeth, as indicated by the arrow.

The lower end of the saw-blade may be hung in the same way, or merely ahole punched in a line with the base of the teeth, by which hole the blade is hooked onto a hook or rod and connected to a pitmanerod. Vhen gan g'- blades are employed, then they must be attached to the devices shownin Fig. 4, said devi ces being formed with hook-like flange plates or strips of metal, as at g g,fwhich hooks work over a ridge or ilange strip attached` to the front side of the upper cross-head, as at s s, Fig. 3, wherein a small gang of saws are shown arranged in their gate and framing. It will be observed, too, that the blades thus arranged at their upper ends are perfectly free and unstrained. Thelower extremities of the blades are attached to clamp-strips r @formed either solidly with eyes or key-places T, in which fit the keys or tightening-wedges a a, Figs. 3, 4; or a simple strip of strap-iron may be employed, folded together and riveted onto thev blade, and forming by the folding thereof the required eye or key-place, thus forming the shank part of the blades. These shanks (when gangs are employed) pass downwardly through alower cross-head formed of two horizontal metal plates,or of a cast-metal head in one piece, as indicated at o e, Fig. 3, and working on ways w w. The shanks are then keyed, as at a u u u, Fig. 3.

In addition to the upper and lower crossheads I employ devices which I term de tachable7 comb-like gage blocks or guides, made of wood or metal and inserted between cast-iron or wooden plates or clamps, as at x (1/ :v i Fig. 3. These gage-blocks can be of various degrees or intervals, according to the thicknessof plank or lumber required. These gage-blocks and plates or clampsare adjustable up and down, and are employed to receive the teeth part or cutting-edge of the saw-blades, and to keep the blades in a vertical line. Thus arranged the back edges of the saw-blades and Aall the surface from the teeth backward to the back edgeare free,unstrained, and divested of all stifness and rigidity. L

By my method of hanging saws each sawblade is separate and independent in itself, and one imperfect blade cannot affect the others, for when a blade by heating expands or elongates or the teeth break,such defective blade can be detached by simply loosening and taking out the keys and dctaching the blade without having to take apart all the gate and other saws. In detaching a blade and substituting another not more than three minutes time is required. Again, too, when a blade elongates, all that is necessary is simply to tighten the key, when the defect is at once remedied, thus avoiding entirely the great trouble of adjusting saw-blades bythe old modes.

It must be readily perceived that, owing to the freedom and iiexible property of sawblades as hung by my mode, rigidity or stiffness of operation is not communicated to the teeth, and consequently, as the line of tension is only downward through thebase ofthe saw- Y teeth,any irregularity or inequality of movement or vibratory action of the parts of lu-m ber being detached from the log cannot vaffect the direction or course of the teeth in the least, but, on the contrary, the teeth control the direction ofthe blade and act as their own guides.

The advantages also attained bymein my mode of arranging and hanging saws are that, as I do not require such a great draft or strain on the blades, I can employ very light, less cumbrous cross-heads, which may be made of cast metal, light an'd perfectly durable, and well adapted in every particular to holding the saws. It will be perceived that the draft on the saw is not throughout its whole width,as in ordinary mill-saws, but merely down through the teeth and the width of the shank attachment r r. Then, again, as the draft or strain of blade is almost entirely ydone away with, wider crossheads,admitting of a greater number of blades,can be employed without requiring any very greatly increased strength of cross-heads. A gang of thirty-six of my saws can bereadily. arranged for use or hung in less than an hour.

Another marked feature of improvement in my self-ranging saws is the fact that four (or more) logs can be reduced to lumber at one and the same time by arranging `two logs abreast and placing two more thereon, and with a greatly reduced increase of power in proportion.

The cost of erecting a gang of saws arranged on my plan is, by actual estimate, about onehalf,A or nearly fifty per cent., less than in the ordinary manner, and the wear and waste in the same proportion.

A gang of thirty-six of my saws with thirtyhorse power runs two hundred strokes per minute with a quarter-inch feed and cut. By

a recent experiment seventy-six boards eighteen feet long, twelve inches wide, fve-eighths thick, were sawed in ten minutes; thus showing` the enormous amount of thirteen hundred l desire to secure by Letters Patent ofthe United and sixty-eight feet, running measure, in ten minutes, eight thousand two hundred and eight running feet per hour, or an average of about eighty thousand feet, runningv measure, per diem often hours.

To attend a gang of thirty-six saws on my plan will require four hands, including runving engine, feeding and supplying the saws, filing and arranging them.

To attend a gang of saws arranged in the ordinary manner will require from eight to twelve hands. Thus it may be seen that'my improvements are of the most important haraeter in their several features of simplicity of construction, cheapness, durability, and expeditious operation.

HavingA described my improved inode of hanging and arranging saw-blades, and clearly shown the marked features of improvement, distinguishing said mode from all others,what I claim as new and ofmy own invention, and

States, is-- 1. The manner or inode of hanging reciprocatingsawblades by forming thereon, or by attaching to the ends and front edge thereof, ears or guide flanges n a, Fig. 2, hook clamps g g, and shank devices o r T, Fig.4, so that the tension or strain and the draft of the blades will be in a direct line longitudinally through the base of the teeth and front edge of the blade, whereby the whole of the surface or 'the plate part of the saw-blade is left free,.un

strained, and divested of all rigidity and stift'- ness, in the manner substantially as described.

2. The adjustable guide-plates with the slotted or grooved gage-pieces gg, Fig. 1, and 1/ x y, Fig. 3, substantially as set forth.

ISAAC N. FoRRnsTER. [L s]

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