Improvements in and relating to the Manufacture of Sheet Metal Spokes for Pulleys.
Year: 1899

page_text: Date of Application, 28th July, 1899-Accepted, 9th Sept.,
1899
Communicated from abroad by CHARLES A. BRINLEY, of Philadelphia, Penn-
sylvania, United States of America.
Improvements in and relating to the Manufacture of Sheet Metal
Spokes for Pulleys.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent Agents,
45, Southampton Buildings, in the County of Middlesex, 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:
In making sheet metal pulleys the same are so constructed that the spoke
arms are formed integral with each other and with a semi-circular central hub
portion, which latter is clamped to the shaft or otherwise formed into the hub
adapted for support upon a shaft.
The present improvements comprehend certain features in the construction of
the said spoke arms and semi-circular hub portions, whereby they may be formed
from a flat sheet of metal suitably blanked out and bent so as to cause the spoke
arms to lie in radial lines from the semi-circular hub portion from which
they project, and furthermore to lie in planes at substantially right angles or
nearly so to the axis of curvature of said hub portion. In the formation of such
spoke blanks a sheet of metal is first subjected to the action of dies which shall
split or cut it to form two or more parallel tongues or arms extending from a
transverse portion at one end which remains uncut. The last mentioned portion
is then bent at substantially right angles to the plane of the tongues and is then
subjected to the action of dies which curve the said uncut portion into a semi-
cylindrical shape, and simultaneously therewith cause the said tongues to
spread apart at their free ends so as to lie in radial lines from the said curved
or hub portion, in which position the said tongues form the spoke in the
subsequently finished wheel. In the methods of forming the spoke blank it will
be observed that the spokes and hub portion are retained as an integral structure,
thereby securing the greatest strength and simplicity in the building up of the
wheel and at the same time the formation of the curvature in the hub portion
absolutely and accurately locates the radial position of the spoke arms relatively
thereto, a feature of the utmost importance in the subsequent finishing and
assembling of the wheel structure. The particular apparatus more especially
under consideration in this application in connection with the method of forming
the spoke blanks is the die mechanism for simultaneously curving the hub
portion and causing the spokes to assume radial positions relatively thereto, and
these die structures consist essentially of a curved or recessed die having a
guiding surface over which the tongues or arms rest, combined with a second die
having a curvature adapted to the curvature of the recess of the first mentioned
die and further having a Hanged portion adapted to fit down over the portions
of the spoke arms adjacent to the hub portion so that while they are spreading
into radial position they are held between the two dies in the proper annular

page_text: location, and the subsequent pressure of the dies causes the metal to set and
the final position of the spoke arms relatively to the hub portion to be definitely
determined.
The improvements will be better understood by reference to the accompanying
drawings, in which:
Fig. 1 is a side elevation of suitable dies for shaping the sheet metal spoke
blanks showing part of the lower die in section;
Fig. 2 is a diagonal section of same on line;
Fig. 3 is a plan view of the blank to be operated upon;
Fig. 4 is a similar view of the blank with one edge bent downward;
Fig. 5 is a cross section on line y-y of Fig. 4.
Fig. 6 is a cross section illustrating the manner of bending the blank shown
in Fig. 3 into the shape shown in Figs. 4 and 5;
Fig. 7 is a plan view of the blank after leaving the dies, Figs. 1 and 2; and
Fig. 8 is a cross section on line ww of Fig. 7.
Reference will first be made to the sheet metal blank and the operations
through which it is put to bring it to the conditions to be acted upon by the
dies shown in Fig. 1 and 2, and then to the nature and construction of said
dies.
A sheet metal blank is first divided by one or more longitudinal slits or cuts.
for a portion of its length so as to form a series of tongues M united to an uncut
transverse portion N as indicated in Fig. 3. Subsequently, the part N is to form
the semicircular hub portion while the parts M constitute the radial spokes. The
sheet of metal shown in Fig. 3 may then be placed between jaws J K, (Fig. 6),
and while the tongues M are clamped, the portion N may be bent downwardly
by a descending die L. The blank will then be in the shape shown in Figs. 4
and 5 in which the parts M and N will be arranged at substantially right angles.
The parts M will of any length desired to suit. the length of spoke necessary for
a given diameter of pulley. The blank in the form last described is next placed
between the dies G, B and subjected to pressure which performs the function
of curving the part N into the semi-circular shape N¹ shown in Figs. 7 and 8, so
as to constitute a portion of the hub of the wheel. At the same time this operation
takes place, the parallel tongues or arms M are caused to shift their positions
relatively one to the other, and arrange themselves in radial lines from the
centre of curvature of the hub portion N¹. It will now be seen that the spoke
arms have been brought into proper relative position for riveting to the rim of
the wheel, and yet, without direct manipulation upon the said arms. It is also
advisable in sheet metal pulleys of this character that the arms M should be
slightly oblique to the axis of the hub and this obliquity is indicated in Fig. 1
and 8, and this is secured by the action of the dies B, G, as will be hereinafter
explained.
Referring now to Figs. 1 and 2 we have the frame A recessed in its upper
portion and fitted with a steel die B, clamped in position by the two clamps D, D.
The die B is formed with a semi-cylindrical recess or depression B arranged
obliquely. C is a backing piece arranged between the lower end of the die B and
the body of the frame A. This backing or lining strip takes up the downward
oblique thrust of the die B, and may also be employed to level up the lower
edge of the blank by upsetting it as is well known in the art of working
metal. Where the width of the hub portion N¹ is to be greater, a wider die B
is inserted and a thinner lining strip C substituted. In this manner the same
die holding frames may be employed for numerous modifications in the size of the
blank. It is evident that if so desired the lining plate C may be dispensed with
or formed integrally with the frame A. The die B is set on an angle with the
direction of movement of the upper die so that there is a combined pressure
exerted upon the internal face B of the die B as well as upon the outer oblique
face thereof. The downward thrust of the upper die also tends to crowd the
Jower edge of the blank down upon the lining plate C, an action which would

page_text: not result if the pressure exerted by the upper die were at right angles to the
curved face of the die B.
F is the upper movable frame, and is movable to and from the lower frame A.
This frame is notched and receives the upper die G which is shaped to correspond
to the working face of the lower die B, while allowing for the thickness of metal
of the blank to be treated. The die G is semi-circular as shown and is provided
at its upper end with a flange H which extends laterally over the outer and
upper face of the die B. Interposed between the upper portion of the semi-
circular die G and the frame F, and arranged. at substantially right angles to
the flange H is a steel lining strip I which directly receives the thrust of the
die G, and at the same time may be replaced to permit a larger or smaller die G,
being employed to suit variations in the size of the hub. The die G and lining
strip I are held in place on the frame F by a bolt f. The adjacent faces b, b,
between the die B and the flange H are oblique to the axis of the curvature of
the dies B and G, as clearly shown in Fig. 1, so that not only do said faces act
upon the spoke arms M to set them but they also cause said spoke arms to be
bent at an angle relative to the semi-circular portion N¹ so that they are made
to lie in a slightly oblique position relative to the axis of curvature of said hub
portion. While this is most desirable it is not essential however. The obliquity
of the surfaces immediately in line with the centre of each of the spoke arms
extends down to the inner curved face B¹ of the die B, as shown in Fig. 2, but the
intermediate parts of said face corresponding to the juncture of the spoke arms
are curved or rounded at the juncture of said face b, and inner curved surface B',
as indicated at E, so as not to put too great a strain upon the metal of the
blank at these places. It will be observed that when the dies approach each other
as indicated in Fig. 1, the corner formed between the flange H and the die
portion G of the upper die, crowds the metal down upon the rounded corners E
and sets the radial arms positively at these points so that their relative positions
to each other and to the semi-circular portions become absolutely fixed.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, as communicated
to me by my foreign correspondent, I declare that what I claim is:-
1. The improvement in the art of forming spoke blanks for sheet metal pulleys
which consists in slitting and bending a sheet of metal, substantially in the
manner described and as shown in the accompanying drawing, whereby the
integral hub is bent into a curved form transversely to the plane of the spokes
and the spokes are expanded into radial positions relative to said hub.
2. The dies for bending the slitted sheet of metal to form the curved hub and
radial spoke arms substantially as herein described and as shown in the accom-
panying drawings.
3. The lining plate C when combined with the recessed die B in the manner
described and supporting the said die B with its upper edge out of contact with
the flanging portion of the die G.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.
Agents for the Applicant.