Improvements in Rotary Cutter Heads for Wood Planing Machines.
Year: 1896

page_text: Date of Application, 3rd Mar., 1896-Accepted, 4th Apr., 1896
COMPLETE SPECIFICATION.
Improvements in Rotary Cutter Heads for Wood Planing Machines.
1, SAMUEL JOHNSTON SHIMER, of Milton, in the County of Northumberland,
and State of Pennsylvania, 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:-
My invention relates to rotary cutter-heads for wood planing machines, having
four sides or faces to the knives used in connection therewith, which knives are
secured to the heads in such manner as to cause the cut to be made alternately
from right to left, and from left to right, diagonally across the face of the board
being planed, which is caused to pass within the radius of the rotating head.
All surfaces formed by means of rotating cutter heads are made up of innumerable
in-cuts or waves upon the face surface, noticeable in proportion to their minuteness,
and it follows that the more varied the direction of the cut, the more nearly
uniform will be the surface.
My invention consists essentially of a cutter head having trapezoidal. faces or
sides alternately arranged and alternately inclined inward and outward of the axial
line of the head, so as to cut from right to left, and from left to right, diagonally
across the face of the board, thereby lessening the tendency of chipping out lumber
which is cross-grained, and modifying the in-cuts on the surface inade by a rotary
cutter-head, by a draw-cut diagonally in alternately opposite directions.
In the accompanying drawings:
Figure 1 is an end view of a trapezoidal cutter-bead made in accordance with my
invention; showing the knives in place therein;
Figure 2 is a perspective view of the cutter-head; the knives being removed;
Figures 3 and 4 are similar views, showing slight modifications in the cutter-
head;
Figure 5 is a front view of the cutter-head shown in Figure 1; the knives being
in place;
Figure 6 is a longitudinal sectional view of one of the knives used with the head
shown in Figure 4;
Figure 7 is a cross section on the line -, Figure 6; and
Figure 8 is a similar view on the line y-y.
Figures 9, 10 and 11 are views similar to Figures 6, 7 and 8, showing the knife
provided with a soft metal facing.
In the said drawings, referring now to Figures 1, 2, 5 and 6, the reference
numeral 1 designates a rotary cutter-head having a central aperture for the mandrel
by which it is rotated. This cutter-head has four trapezoidal faces, alternately
arranged, and inclining inward and outward of the axial line of the head. That is
to say, two opposite sides of the head are inclined from one end of the latter away
from the axial line of the head, while the other faces or sides are inversely inclined,
or slanting from the same end of the head, they inclining towards the axial line of
the head.
Each of the sides of the faces is formed with a T-channel or groove 2, and
working in these grooves are screw-bolts 3, having angular heads 4. These bolts
pass through slots 5, in knives 6, and are provided with washers and nuts 8. The
numeral 9 designates beveled lips at the front edge of each side of the cutter-head,
and extending from end to end thereof.
It will thus be seen that the knives are inclined, or at an angle to the axial line

page_text: of the head, and the said faces or sides of the latter, being inclined in opposite
directions, and the cutting edges of the knives being curved in the form of a
segment of an ellipse, as the cutter-head is rotated, the knives will alternately
make a shear cut from right to left, and from left to right, diagonally across the
face of the board.
In the modification shown in Figure 3, the trapezoidal sides or faces, instead of
being flat, as shown in Figures 1 and 2, are convexed longitudinally from end to
end of the head. The knives in this instance, are made with a straight cutting
edge and are sprung down and bolted upon the head, assuming a concavo-convex
shape, and the cutting edges will thus be convexed so that any point thereof will
be at the same distance from the center of the head.
In the modification shown in Figure 4, the sides of the head are reversely formed.
that is to say, instead of being convexed, they are made concave longitudinally, and
the underside of the knives are correspondingly curved, see Figure 9, from the
center to the ends so as to seat therein, so that they will he thinner at the ends,
than at the center. These knives have their cutting edges formed in the shape of
segment of an ellipse, and may also be used with the cutter head shown in
Figures 1 and 2, by providing the cut-away undersides with a facing 10, of soft
metal, see Figures 10 and 11, so as to form a perfectly flat surface.
A knife constructed, as shown in said Figures 6, 7, and -8, can be readily
sharpened by bringing the cutting edge within the limit of a straight bevel, so that
an ordinary workinan can keep the knife in order.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
-claim is-
1. A cutter-head having four trapezoidal sides or Inces.
2. A cutter-head having four convex trapezoidal sides or faces.
3. A cutter-head having four concave trapezoidal sides or faces.
4. A cutter-head having four trapezoidal sides or faces in combination with
knives secured thereto.
5. A cutter-hend having four trapezoidal sides or faces in combination with
knives secured thereto baving their edges curved in the form of a segment of an
ellipse.
6. A cutter-hend having four trapezoidal convex sides or faces in combination
with the knives secured thereto.
7. A cutter-head having four trapezoidal concaved sides or faces in combination
with knives secured thereto having their undersides convoxed longitudinally.
8. A knife for a rotary cutter-head convexed longitudinally on its underside and
the cutting edge curved in the form of a segment of an ellipse.
9. A knife for a rotary cutter-head having its underside convexed longitudinally
and provided with a soft metal facing forming a flat surface or seat.
Dated this 2nd day of March 1896.
H. B. BARLOW & GILLETT,
17 St. Ann's Square, Manchester, Agents for Applicant.