US77148A - Improvement in dove-tail machines - Google Patents

Description

' D. Wife, .Doz/fazmyzia METERS. PHOTO-UTHOGRAPNER. WASHINGTON. D. c.

@Hit-2li tant-gattini @ffice Lene-s Paten No. 77,148, ma Apt-a 21,1868.

IMPROVEMENT IN DOVE-TAIL MACHINE-S4.

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TO WHOM IT MAY CONCERN: x

Be it known that I, TnAYnn D. WHITE, of Cincinnati, Hamilton county, Ohio, have invented a new and useful Machine for Sawing Dbve-Tails; and Ldo hereby declare the following to bea full, clear, and exact description thereof, reference being had to the accompanying drawings, making part of this specification.

My invention relates to a machine for simultaneous sawing of the kerfs of an cntiroseries of dove-tails,

without the necessity of laying out the work.

Figures 1, 2, and 3 are top views of my machine, as adapted, respectively,'t`or -headingpins for mortises,

and for open pins.

Figure 4 is a transverse section, taken at the line :c :v,-`Ig. 3. Figure 5 is a longitudinal'section, taken at the line g/ y, iig. 1. A isa frame, provided with ledges B B' C C', made adjustable in height by rcasonof their oblique lowcr edges resting upon correspondingly oblique supports in the frame. These ledges Vserve to support at any desired heght'and'angle the various beds on which the stuit is supported, and along which it is advanced to its work.

Journalled transversely athwart the frame isia shaft, D, having a driving-pulley, E, and a gang of circular saws, F, whose number corresponds'to that of the desired dove-tails, and of such decreasing diameters, from oneend to the other of the series, as that a line joining the lowest portions of their peripheries shall be parallel toa stationary bed or bench, G, whichdeclines from point 1 to point-2, at lan angle with the planes of the saws precisely corresponding to the i-are of the desired dove-tails. The saws are held-properly apart by means of washers, I, and are held fast by means of a n ut,vJ, tappedrupon the shafts. i

The stuff Z being placed with one edge in contact with the gauge H, is pushed under the .gang of saws a suiiicieut distance to cut the right or left side, as the case ay be, of a series of heading-pins for: secret dovetails, a suitable stop underneath the saws determining the advance of the stuff.

' One set of kerfs, corresponding, we will say, to the left sides of the pins, having been sawn, the corresponding set for the right sides, (see dotted Iines,) are sawn by advancing th'e stud from the other end. of the bed.

Where it is desired that -the kerfs shall not be carried further back than the bases of theipins, the sloping bedis elevated bodily somewhat higher, and a gang of saws is employed which diminish less rapidly in diameter. The stops also are so arranged as to arrest the stuit .at an earlier portion ot'. the stroke.

For sawing the mortises, the stuit is placed upon a horizontal travelling-bed or rest, K or K', which rest is restricted to a rectilinear path parallel to and half the thickness of the stui below the saws axis.V

The bed K or Khas a sidegauge, L, of corresponding ohliquity to the flare of the mortises, and a stop',- M. One set of sides having been cut as in fig. 2, a precisely similar operation on thc corresponding bed K', cuts the remainingr sides, (see ldotted lines.) 1 l For sawing pins clear through, the arrangement shown in figs. 3 andAi is employed, and in which the' sloping bench has an additional slab, N, whose surface is, atits midewith, half the thickness of the stuff below the' plane of the saw-shaft. i p I I The other end of the machine has a similar slab, N', and'the'se slabs are provided with stops, n at', and adjustable gauges, O O. In this arrangement the saws, instead of converging towards one end, are of very slightly-increasing'diameters from the middle to the outside blades, so as to secure the represented equal pene' tration. In the drawing'this disparity of diameters is exaggerated, for 'greater clearness of representation. g

The above-described inequality of diameters is necessary, because one edge of the board has to be as unich below the centre as its opposite edge is above it. n.

R and S are wedges at the ends of the machine, and they aire employed in connection with the ledges B B', C C', for bringing the table Gr to a proper elevation. Y

Mortisc and heading-.pins can be sawed, without any change of saws, by depressing the lower rest as much belowvthe periphery of the saws as you want to appear in front of the pins.

To saw heading-pins on an angle of forty-,live degrees, or near that, the saws are allreniovcd except thc two largest, and in thei-r place I substitute three others, the smallest of which is ono-twelfth larger than the smallest which has been removed, or near that size, the other three being of a size to bring their peripheries on a line with the two outside saws; they will then make a more obtuse angle than these you took oii, which is necessary in order that the saws may all cut the same depth.

To saw pins clear through, take offall but the large saw, and put on four others, the largest of which is the same size as the one left on, and has to go on last. The next two being of equal size, go next to each outside saw, and the smallest in the centre, so that a line drawn along their peripheries will he slightly concave, as shown in iig. 3. This is necessary, as one edge of the board has to be as much below the centre as its opposite edge is above it; the centre saw would cut beyonda line the outside ones would eut to if they were all of a size. The unequal diameters of the saws enables them to eut tenons of equal length, because, by reason of the vertical Obliquity of the bed, the middle saw only can work with that part of its edge which is at the greatest horizontal distance from'the shaft. It is only the centre of the width of the plank that is fed radially toward the arbor, and hence if the saws were of equal diameter, the centre one would begin to cutiirst, and would eut vto a greater depth than 'the others.

' Figures 6 and 7 are diagrams illustrating this operation, the former being an elevation, and the latter a plan. The red lines indicate the position of the plank, but its Obliquity is exaggerated, in order to make the ,effectA more clear. i J v If the boards to be dove-tailed have parallel edges, and of equal width, there is but one slide and guide necessary in sawing mortises, as you turn the piece over and finish. In sawing pins, if the pieces are of the same width, a guide on one side is sufficient, but it is necessary to saw from both sides ofthe machine.v

The spaces between the saws must all be the same. In order to dove-tail wider pieces than this machine represents, a greater number of sawscan be employed.

Five different widths may be dove-tailed by usingone less saw for each width, which would give the ser eral widths six, five, four, three, and two pins, or the saws may be placed near together by providing a set-of thinner blocks between them, and thus accommodate therh to any desired width, but in so doing you make a more acute angle, and will have to accommodate the rests to it.

Ifthe saws are placed farther apart, 'the angle is more obtuse, and the rests will have to be altered so as to agree withit. l

It will be seen that both the mortises and the corresponding heading-pins may be sawn without change of saws, providing there is no objection to having the kerfs ofthe pins extend somewhat beyond their bases; but

where this is objectionable, a change of saws, asabove explained, will be required.

The same saws may be employed for hidden pins and mortises, bythe use of larger washers, but in that ease the obliquity of the'beds and gauges must be correspondingly lessened. y I have described the apparatus as applied where the series of dove-tails is equally distant from both edges of `the stuii, but where this is not the case, the' work must be gauged from one edge only, and for this'purpose 'I workfrom a gauge on the right instead of the left, or vice versa, for the second cutting, t'o complete thepins or mortises, as the case may be.

'I claim herein as new, and of my inventien- The combined arrangement of a series oi' saws of unequal diameters, and an oblique table for feeding planks thereto, as and `for the purposes herein specified.

In testimony of which invention. I hereunto set my hand.

THAYER. D. WHITE.

Witnesses:

GEO. H. KNIGHT, JAMES II. LAYMAN.

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