US170578A - Improvement in scroll-sawing machines - Google Patents

Description

- 2 Sheets-S heet1. W. C. MARGEDANT. SCROLL SAWING-MACHINE. 17o,'573, I Patented Nov. 30, 1875.

WITNESSES u PEIERS. PHOTO-LITHOBRAPHER. WASHINGTON. DV 0.

. z sheets-sheen.

W. C. MARGEDANT. SCROLL SAWING-MACHINE.

No. 170,578. Patented Nov. 30, 1875.

Z? n I H r WITNEf- E N.PETERS. PHOTO-LITHOGRAPMER, WASHINGTON. D C.

UNIT D STATES PATENT OFFIon.

WILLIAM C. MARGEDANT, OF HAMILTON, OHIO, ASSIGNOR TO BENTEL, MARGEDANT & 00., OF SAME PLACE.

IMPROVEMENT IN SCROLL-ISAWING MACHINES.

Specification forming partof Letters Patent No. 170,578, dated November 30, 1875 application filed July 28, 1875.

To all whom it may concern:

Be it known that I, WILLIAM C. MARGE: DANT, of Hamilton, in the county of Butler and State of Ohio, have invented a new and useful Improvement in Scroll Sawing Machines; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings forming part of this specification, in which- Figure 1 is a front elevation of the jigsaw stand and the straining apparatus with double springs. Fig. 2, asectional view through the line 11 c. Fig. 3 shows the straining device consisting only of one spring attached to a stanchion illustrating the different positions of the ends of the springs at the extremities of the movement of the saw-blade. Fig. 4 is an elevation of the straining device, the fulcrum of the radii moving on adjustable centers Fig. 5, a top view of Fig. 4; Fig. 6, an elevation of the cross-head; Fig. 7, a top view of the cross-head. Figs. 8 and 9 are modifications of the spring; Fig. 10, a modification of the spring as adapted to be used with two acting levers.

My invention relates to that class of scrollsaws wherein a serrated linear blade is given 'a vertically-reciprocating motion by means of a crank, pitman, and cross-head, and where the blade is held ata uniform tension or strain at all attitudes of the saw-blade.

My improvement refers particularly to the apparatus or device which imparts to the'serrated blade a certain amount of strain necessary to support the blade in its rapid reciprocating motion.

Experience has established the fact that most of the devices now in use for straining the blade are lacking those qualities which are necessary to obtain the required result, viz., a uniform strain at any point of the motion, a quick and sensitive action, and the adjustability and simplicity of wearing parts.

In the drawings, A is the main stand or table, cast in one piece, provided with the usual driving pulley, crank-wheel, pitman, crosshead M, and saw-holder. B is the stanchion or hanging standard, suitably attached to the ceiling, and supporting the adjustable plate 0, which carries the adjustable springs D and D. The latter are held by the straining-loops E E. (Shown in Figs. 2, 4, and 5.) The straining-loops E E pass through the spring-saddles F F. The spring-saddles are provided with toothed collars G G, and pass through the adjustable plate 0, and are fastened by means of a screw-nut. The toothed collars G G are in contact with the ratchet-pawls H H. The ends of the springs D and D hold and press the radii levers I I, which are connected with the saw-blade by leather strips or Wire rope. The adjustable springs D D are formed of a bar of steel, which tapers oft toward the ends.

It is not essential that they should be tapered at all, or tapered toward one or both ends. In some cases better results are obtained by making one end of the spring, which acts as the fulcrum of the radii or lever I,

heavier than the other end. The principle feature is the bending of the bar in a circular, oval, or other suitable form or shape, so that the ends of the bar meet, as shown in Fig. 8; or that they pass in close proximity, as shown in Fig. 9.

If only one lever is acting on both ends of one spring, the points of contact or pressure should not meet in the same line, as the pressure on one side of the lever would be counterbalanced by the pressure on the opposite side.

If two levers are applied to one spring, as shown in Fig. 10, the ends of the spring may meet in one common line. I prefer, now, the application of one lever for obtaining a reciprocating motion, because the number of parts and friction is reduced.

Between the bearing ends of the bent spring should be a certain distance established to obtain leverage or mechanical advantages. The dimension of the distance must be made in conformity with the amount of pressure required, strength and size of the spring, length of the lever, and the length and acuteness of its action wanted.

Most of the springs which have been so far used for reciprocating machines, are irregular and multiplying in force. By the use of cone and eccentric pulleys, and other devices, this defect of springs has been partly remedied, but another defect estabIished-that of complication of'pa-rts and connection, and consequentlj a loss of direct motion,.increase in weight, and friction.

. The construction of my improved spring, the attachment and operation of the lever, as well as the ad justability of the same, gives an equal strain at the whole lengthiof motion,

.and consists of very few parts.

Fig. 3 shows a single spring in rest, and the position of the radii lever and spring when in action.

It will be noticed that the spring opens when the lever is depressed; but the distance between the ends of the spring, and consequently the leverage, and the leverage action between the same, are also diminished. By depressing the lever more, thepoints of pressure meet in one common line. i

I prefer to arrange the spring and lever in such a manner as shown in Figs. 1, 2, and 3, if only light and quick sawing is required. For heavy work I believe the arrangement shown in Figs. 4 and 5 gives a better result. The difference in the latter device from the former consists in the use of an adjustable fulcrum on which the lever swings.

It will be observed that in Figs. 1 and 3 the lower end of the spring D is the fulcrum of the lever I; butit is not a fixed or stationary fulcrum. Its action is similar to the upper part of the spring.

Figs. 4 and 5 show the lovers 1 I held by two pointed set screws, which establish-the fulcrum of the lever movement.

Thasprings may be adjusted to press more on the upper or lower side of the levers, as

the nature of the work may require.

The plate 0 can be provided with slots K, so as toadjust the springs, including centerscrews.

. The strain or pressure of the saw may be increased or reduced by the hand-wheel L.

Fig. 3 shows the arrangement on a large scale. The spring D rests on thespring-sad dle F on two higher points, f f, which said points or projections cause the two ends of the spring D to be pressed together and stiffened when the straining-loop E is tightened, so that the said spring may be adjusted as to its tension. By loosening a fastening on the strain-loops E E, the two ends of the spring will impart less pressure to the lever I.

the cross-head M. As that part of the machine should combine great strength andlight ness, I prefer to make it of two steel plates,

M M. A piece of suitable plate-steel is cut cylinder. The wooden pitman is held to the journal-pin by means of washers O, which are held by small screws inserted partly in the hollow pitman-pin. As the screws X, which i hold the washers O and pitman P, do. not meet, an empty space is formed inthe pitman pin, which I fill with plumbago, or other suit able lubricator. By boring several small holes, a, from the outside of the pitman-pin to the lubricating-chamber, the contentswill be thrown by the reciprocating force to the hearing parts of the pitman and pin.

By cutting-superfluous metal away, a webslide is produced with a hollow pin which is very light and strong, and which carries in itself a lubricator which lubricates automati: cally the working parts when the saw is, in

motion and lubrication is needed. The crankpin, connecting the pitman with the crankwheel, is also hollow, and provided with channels for lubrication.

The application of spring or springs, as specified, as well as that of a lubricating-pin on other machines, I shall preserve.

Having thus described my invention, what I claim as new is-- 1.' In a scroll-saw, a straining or spring dey I vice consisting of a barof steel or other SlllU-fi able material, bent in such a form that both ends of the spring are in close proximity, in combination with a lever of suitable forminserted between the ends of the spring, as do,

scribed, so that the action of the spring is transmitted to the lever, and transformed thereby into a reciprocating motion, substan tially as described.

2. In a scroll-saw, a spring formed of a bar of steel or suitable material, bent as described, so that the ends of the bar come in GIOSBiPI'OX- imity, in combination with a lever which swivels on an independent fulcrum, while one end of the spring is active in front, and the other end of the spring is active on theopposite side of the fulcrum of the lever, substan- 1 tially as described. r r

3. The slides formed of plates M M, in combination with the hollow pitman-pin, having holes a, the washers O, and screws X, as arranged, and for the purpose specified.

WM. 0. MARGEDANT.

Witnesses: 1

P. H. GERHARD, JOHN SEEMAN.

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