Year: 1887

page_text: 1, JOHN CALDWell Humphreys of Braxton Court House, in the county of
Braxton and State of West Virginia, United States of America, Gentleman, do hereby
declare the nature of this invention and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement:-
This invention relates to rotary cutter-heads for planing lumber or other material 3
and it consists in certain novel constructions and combinations of parts, as herein-
after described, and pointed out in the claims.
Reference is to be had to the accompanying drawings, forming a part of this
specification, in which similar letters of reference indicate corresponding parts in all
the figures.
Fig. 1 represents a longitudinal view of a rotary cutter-head embodying my inven-
tion. Fig. 2 is an end view of the same as seen from the left-hand side of Fig. 1, and
Fig. 3 a transverse section thereof upon the line in Fig. 1. Fig. 4 is an outer face
or back view of one of the cutting-bits detached; Fig. 5, an inner face view, upon a
larger scale, of a washer provided with a pocket used in securing and balancing the
bits; and Fig. 6, a transverse section thereof upon the line y y in Fig. 5.
A is the cutter-bar, stock, or bit-holder of the rotary cutter-head, having a series of
exterior convex surfaces, 6 and 6', eccentric to the axis of the cutter-bar, and shaped
so that the cutter-bar or bit-holder, as viewed from its opposite ends, prevents two
three-leaved cams, each of which extends half the length of the cutter-bar, and so
that the advance edges c, which are the edges farthest removed from the axis of the

page_text: cutter-bar of the cam-like surfaces or portions b, are centrally intermediate of the
corresponding edges c of the cam-like surfaces or portions 61, whereby the several
edges cc divide a circle which would circumscribe them into six equal parts. These
convex surfaces bb form the eccentric bearings, as in other cutter-heads differently
constructed, for the cutting-bits B B', each of which is one-half the length of the
cutter-bar, thus making the bits of one series intermediate of those of the other. The
advance or cutting edges of said bits of course slightly overlap the edges cc of the
portions, and, taking the two series of bits B B₁, divide the circle circumscribed by
them into six equal parts.
With the several bits arranged as described only one bit will cut at a time, thus
requiring only about one-half the power to drive the cutter-head as if two bits
were cutting simultaneously, and the hits project at such tangents and are so shaped
on their backs that their outer surfaces back of the cutting-edges lie inside of the circle
described by the cutting-edges, whereby the bits in cutting the wood work at an angle
of from fifteen to twenty degrees, or thereabout, to it, instead of at an angle of
forty-five degrees, as is generally the case, and do not drag or leave creases or ridges
in the surface of the wood being dressed, but cut in contradistinction to scraping it,
and not only ecomize driving power but wear and tear of the belts and machinery
used to operate the cutter-head.
The bits B B are secured to their places on the cutter bar or stock by screws C,
arranged to enter said bar or stock and to pass through open-ended slots e and
washers D in the bits, said washers being of irregular shape to prevent them from
turning, and fitting within countersunk marginal portions of outside of the slots.
Every facility is accordingly afforded for attaching and removing the bits as required
and to hold them securely in place.
The several bits B B' are similar in construction or shape and size, so that they are
interchangeable. This is important, as I have found from experience that the bits in
rotary planing cutter-heads generally wear more in the middle of their lengths than at
their ends, which heretofore it has been usual to remedy by grinding. By using the
two series of bits, however, and making the bits of the one series interchangeable
with those in the other series-that is, the bits B interchangeable with the bits B-
I largely avoid this, as in interchanging or transposing said bits their outer ends
become their inner ends on the cutter-bar. Furthermore, it is important, as is well
known, in rotary cutter-heads running at a high rate of speed, that the several bits
should be of the same weight one with another. This, too, has usually been done by
grinding the bits. To obviate this I construct each washer D with a pocket, g, on its
inner side, in which may be placed shot or other weights s, and thus virtually provide
for making the several bits of the same weight, or, in reality, the portions of the
cutter-head occupied by the several bits of like weight, thereby doing away with any
irregularity in the motion or action of the cutter-head by an unequal distribution of its
weight. By removing or adding weights s this adjustment can be very accurately
effected without having resort to grinding the bits. This arrangement of pockets in
the washers D, adapted to carry adjustable weights, is virtually the same as similarly
and adjustably loading the bits themselves, and in some cases I make the bits also with
pockets, in which to place shot or weights.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what 1
claim is
1. A stock or bit-holder having two series of convex surfaces, 66¹, eccentric to the
axis of the stock, each series extending half the length of the said stock, with the
advance edges c of one series of convex surfaces centrally intermediate the advance
edges of the other series of convex surfaces, substantially as herein shown and
described.
2. The combination of the cutter bar or stock A, having a double series of eccentri-
cally-curved equidistant bit-bearing surfaces, 6 b', each series extending half the length

page_text: of the cutter bar or stock, with the advance edges c of one series centrally intermediate
the advance edges of the other series, the detachable and interchangeable bits BB', of
equal length throughout, constructed to fit the said bearing-surfaces and adapted to
cut at an acute angle, and means for detachably securing the bits to the cutter bar or
stock, substantially as herein shown and described.
3. The washers D, provided with pockets g, adapted to carry removable weights, in
combination with the cutter-bar and a series of bits arranged around said bar, and the
screws C, substantially as and for the purpose herein specified.
Dated this 10th day of December 1887
HORN & SON,
Agents on behalf of Applicant.