IMPROVEMENTS IN APPARATUS OR MEANS FOR TRANSMITTING POWER, APPLICABLE ALSO TO THE RAISING, LOWERING, MOVING, OR TRANSPORTING OF HEAVY BODIES
Year: 1877

page_text: LETTERS PATENT to Daniel Mills, of Newfield, in the County of Gloucester,
and State of New Jersey, United States of America, but now residing in Bir-
mingham, in the County of Warwick, Mechanical Engineer, for the Invention
of "IMPROVEMENTS IN APPARATUS OR MEANS FOR TRANSMITTING POWER,
APPLICABLE ALSO TO THE RAISING, LOWERING, MOVING, OR TRANSPORTING
OF HEAVY BODIES." A communication from abroad by John T. Hawkins, of
Salisbury, in the County of Addison, and State of Vermont, United States of
America
Sealed the 3rd May 1878, and dated the 13th November 1877.
PROVISIONAL SPECIFICATION left by the said Daniel Mills at the Office of
the Commissioners of Patents on the 13th November 1877.
DANIEL MILLS, of Newfield, in the County of Gloucester, and State of New
Jersey, United States of America, but now residing in Birmingham, in the County
of Warwick, Mechanical Engineer. "IMPROVEMENTS IN APPARATUS OR MEANS
FOR TRANSMITTING POWER, APPLICABLE ALSO TO THE RAISING, LOWERING, MOVING,
OR TRANSPORTING OF HEAVY BODIES." A communication from abroad by John
T. Hawkins, of Salisbury, in the County of Addison, and State of Vermont, United
States of America.
This Invention relates to a peculiar construction of driving belts, and of pullies to
be used therewith, for transmitting power from one shaft to another, also to a
peculiar construction of teeth or studs and projections or recesses to be applied to
such belts and pullies respectively, by which the absorption or loss of power
arising from the friction or sliding of one tooth or stud along the side of the
other is obviated.
According to one part of this Invention, it is proposed to employ endless gearing
consisting of teeth or studs secured by rivets, bolts, or otherwise to a belt consisting
of one continuous strip, or of two or more strips of metal or other suitable flexible
material without hinged joints and that will not stretch, preference being given to
metal strips of steel, hard rolled brass, phosphor bronze, or sheet iron, made suffi-
Driss 17

page_text: ciently thin and being so tempered as to conform to the curves of the pullies
without taking a permanent set. The strips when in lengths, in lieu of being flat,
may be curved to about a medium between the curves of the pullies and a straight
line.
In order to obtain greater and more complete flexibility in the belt at the parts
where the teeth are secured, the surfaces of the said teeth next to the belt are more
or less bevelled or chamfered in proportion to the size of such teeth, thereby allowing
freedom for the belt or the series of strips composing the same to conform more
accurately to the curve of the pulley than would be the case if the base of the tooth
were entirely flat. I prefer to make the teeth on the belt of leather, raw hide, wood,
or similar material. which will work without jarring noise, but I do not confine
myself to any particular material.
The pullies to be used with this system of endless gearing. are also provided on
their peripheries with projections or hollows corresponding to, and gearing accurately
with those on the belt. The said belts may in some cases be composed of a number
of lengths of material disposed side by side, edge to edge, such strips breaking joint,
and being, by preference, rounded on the edges to obviate the tendency to fracture,
and being also connected either by transverse pieces constituting in themselves the
gear teeth, or connected by transverse thin metal strips and having the said gear
teeth or studs secured to the longitudinal strips. When transverse pieces are used
for the teeth I sometimes taper them from end to end in alternate directions, and
have corresponding tapered teeth or recesses on the pulley, thereby preventing the
lateral displacement of the belt.
In order to avoid all friction resulting from the sliding or rubbing together of
the sides of the aforesaid teeth or studs, and projections or recesses, it is further
proposed according to this Invention to employ teeth, studs, projections, or hollows
of such a contour on their acting sides that they shall neither roll nor slide against
each. other when coming into gear. I make the sides of the said teeth, projections,
or recesses, on the pulley and belt either curved or flat; and when curved, I prefer
that the said curve should form an arc of an involute, and be such that a tangent to
any part of the curve of their sides shall make a less angle with a tangent to the
periphery of the pulley at the origin of the involute than does the tangent
to the involute at the point of intersection of the top of the tooth. If their
sides be flat or straight, then their inclination should, by preference, make a
less angle with aforesaid tangent to the periphery of the pulley than does the
aforesaid tangent to the involute. These angles vary of course for different
diameters of pullies, and the teeth may either consist of frustums of cones, described
as above, or of ribs or projections extending across the belt or pulley.
The herein-before described endless involute gearing is also obviously applicable
to the raising, lowering, moving, or transporting of heavy bodies.
I am aware that endless pitch chains or hinged drivers have been used, also. thin
flexible metallic continuous belts made from rolled wire or rods, and having teeth
made out of the same material and in one therewith, by rolling, and therefore I do
not claim any such arrangement or combination of driver; moreover, the teeth
so formed out of the solid materially interfere with the flexibility of the belt, and
.render it liable to break off at the angles of the teeth, whereas in the improved con-
struction herein-before described a much greater flexibility and durability of belt is
ensured.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Daniel Mills in the Great Seal Patent Office on the 13th May
1878.
DANIEL MILLS, of Newfield, in the County of Gloucester, and State of New Jersey,
United States of America, but now residing in Birmingham, in the County of
Warwick, Mechanical Engineer. "IMPROVEMENTS IN APPARATUS OR MEANS FOR
TRANSMITTING POWER, APPLICABLE ALSO TO THE RAISING, LOWERING, MOVING OR
TRANSPORTING OF HEAVY BODIES." A communication from abroad by John T.
Hawkins, of Salisbury, in the County of Addison, and State of Vermont, United
States of America.
The said Invention relates to a peculiar construction of toothed driving belts and
of pullies to be used therewith for transmitting power from one shaft to another,
such belts and pullies being provided with teeth, studs, projections, and recesses
of a peculiar construction, by which the absorption or loss of power arising from the
friction or sliding of one tooth or stud along the side of the other is obviated.
In carrying out this Invention, it is proposed to employ endless gearing consisting
of teeth or studs of the peculiar construction and arrangement herein-after described,
secured by rivets, bolts, or otherwise to a belt consisting of one continuous strip, or
of two or more strips of metal or other suitable flexible material without hinged
joints, and that will not stretch, preference being given to metal strips of steel, hard
rolled brass, phosphor bronze, or sheet iron made sufficiently thin and being so
tempered as to conform to the curves of the pullies without taking a permanent set.
When the strips are made up of short lengths, such lengths in lieu of being
flat may be curved to about a medium between the curves of the pullies and a
straight line.
In order to obtain greater and more complete flexibility in the belt at the parts
where the teeth or projections are secured, the surfaces of the said teeth or projec-
tions next to the belt are more or less bevelled or chainfered in proportion to the
size of such teeth, thereby allowing freedom for the belt or the series of strips
composing the same, to conform more accurately to the curve of the pulley than
would be the case if the base of the tooth or projection were entirely flat. I prefer
to make the teeth on the belt of leather, raw hide, wood, or similar material
which will work without jarring noise, but I do not confine myself to any particular
material.
The pullies to be used with this system of endless gearing are also provided on
their peripheries with projections or hollows corresponding to and gearing accurately
with those on the belt. The said belts may in some cases be composed of a number
of lengths of material disposed side by side, edge to edge, such strips breaking joint,
and being, by preference, rounded on the edges, to obviate the tendency to fracture,
and being also connected by transverse thin metal strips, and having the said gear
teeth or studs secured to the longitudinal strips, by preference at the intersections
of the transverse strips. When transverse pieces are used for the teeth, I some-
times taper them from end to end in alternate directions, and have corresponding
tapered teeth or recesses on the pulley, thereby preventing the lateral displace-
ment of the belt.
In order to avoid all friction resulting from the sliding or rubbing together of
the sides of the aforesaid teeth or studs and projections or recesses, it is further
proposed, according to this Invention, to employ teeth, studs, projections, or hollows
of such a contour on their acting sides that they shall neither roll nor slide against
each other when coming into gear. This contour I shall now proceed to describe.
The path described by a point in such a driving belt referred to, the corresponding
point on the periphery of the pulley which it enwraps will be the curve known as
an "involute."
In Figure 1 of the Drawings, A, E, C, is the periphery of the pulley; E,T, F, an

page_text: involute described from the point E by the point F¹ in the belt G', F¹, ƒ; G, T, H,
is a part of the circumference at the tops of the teeth, and a, b, a tangent to the
involute at the point T.
Now, a tooth upon the pulley or the belt of such form as to engage similar teeth
on the belt or pulley, so as to meet and engage without rubbing or friction between
them, must, if the sides of such teeth be curved, be such that a tangent to any part
of the curve of their sides shall make a lesser angle with the tangent of the peri-
phery of the pulley at the origin of the involute B, D, than does the tangent to the
involute a, b, as shown in the dotted line a¹, 61. If their sides be flat or straight,
then the inclination of these sides must make a lesser angle with the tangent B, D,
than does the tangent to the involute a, b; that is to say, if the angle 6¹ be the angle
made by a tangent to any point of the curved side of a tooth, or the flat side of a
tooth, and the tangent B, D, and be the angle made by a tangent to the involute
taken at the top of the tooth with the tangent B, D, then 61 must always be less
than .. These angles vary for different diameters of pulley; but the rule here given
will apply to all cases.
The teeth may either consist of frustums of cones described as above, or in some
cases of ribs or projections extending across the belt or pulley.
Figure 2 of the Drawings shows an edge view and inside plan of the simplest
form of the improved belt.
a is a single metal strip, and b, b, are conical projections secured thereto, the
acting sides being inclined after the formula herein-before given.
Figure 3 shows the application of transverse teeth or projections b, b, to two metal
strips a, a, disposed parallel to each other, and composed of several short lengths of
metal disposed side by side and breaking joint, and connected by the projections
themselves.
Figures 4 and 5 represent respectively an edge view and plan of a belt composed
of several short lengths or strips of metal a, a, disposed side by side in any number
of parallel rows (three being shown in the Drawings) and breaking joint, the said
strips being connected outside the belt by the transverse thin metal strips c, c ; b, b,
represent a number of frustums of cones, one of which is shown full size at Figure 6.
The acting sides of each cone are either curved or inclined after the formula above
given, and the base of each cone is slightly bevelled or rounded, as shown at d, d,
(Figure 6), in order to afford freedom for the flexure of the strips a in adjusting
themselves accurately to the periphery of the pulley.
Figures 7 and. 8 represent respectively in section and plan a portion of a pulley
to be used in conjunction with the last-described belt.
a is a portion of the periphery of the pulley, and b is one of a series of projections
fitted transversely thereon; such projections having recesses b', 61, made therein,
which recesses conform to the shape of and receive the frustums of cones b, b, on
the belt.
Figures 9 and 10 represent respectively in section and plan a portion of a pulley
to be used in conjunction with a belt having transverse teeth.
This system of endless involute gearing, besides transmitting power through lines
of heavy rotary shafting for driving large machinery, is abundantly capable of
exerting any necessary power when adapted to the elevating to great heights of
large volumes of heavy materials, heretofore so elevated by hinged or frictional
conveyers only.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried into
effect, I would observe in conclusion that I am aware that endless pitch chains
or jointed or hinged drivers have been used, also thin flexible metallic continuous
belts made from rolled wire or rods, and having teeth made out of the same
material, and in one piece or solid therewith by rolling, and therefore I do not
claim any such construction of driver. Moreover, the teeth when formed out of the
same material and in one piece with the metallic belt, greatly interfere with the
flexibility of the belt itself, and render it liable to fracture at the angles of the teeth,

page_text: whereas by the improved construction herein-before described, a much greater degree
of flexibility, durability, and facility for repairs of the belt is ensured, whilst all
unpleasant noise and jarring when at work is obviated. But what I consider to be
novel and original and therefore claim as the Invention secured to me by the herein-
before in part recited Letters Patent is,―
First. In a system of endless gearing, a pulley or pulleys having upon the face or
faces thereof non-rolling, non-sliding, and frictionless teeth, cogs, or recesses of the
form described, gearing with or interlocking corresponding teeth or projections upon
an enwrapping belt, substantially as specified.
Secondly. In a system of endless gearing, the use of frustums, of cones, of the
contour set forth, secured to a single continuous thin flexible metal strip by rivets,
bolts, or equivalent fastenings, substantially as herein-before described and illustrated
by Figure 2 of the Drawings.
Thirdly. In a system of endless gearing I claim a belt composed of two or more
continuous thin metal strips disposed side by side, and connected by transverse
thin metal strips in combination with the peculiar frustums of cones as herein-
before described.
Fourthly. In a system of endless gearing I claim a belt composed or built up of a
number of lengths of metal strips disposed side by side and breaking joint in com-
bination with transverse connecting metal strips and with the said peculiar frustums
of cones, substantially as herein-before described and illustrated by Figures 5 and 6
of the Drawings.
Fifthly. In a system of endless gearing I claim the application of transverse teeth,
ribs, or projections of the form described when used in conjunction with a belt
composed or built up of a number of lengths of thin flexible metal strips disposed side
by side and breaking joint, substantially as herein-before described, and illustrated
by Figure 3 of the Drawings.
Sixthly. In a system of endless gearing I claim curving the metal strips before
being rivetted together, substantially as and for the purpose herein-before described.
Seventhly. In a system of endless gearing I claim a pulley lagged with wood or
other suitable non-metallic material, wherein the recesses for the said peculiar
frustums of cones are bored or otherwise formed in combination with a corresponding
belt of the construction herein-before set forth.
Eighthly. In a system of endless gearing I claim a pulley lagged with strips of
wood or other suitable non-metallic material which form the transverse projections in
combination with a corresponding belt of the construction herein-before set forth.
In witness whereof, I, the said Daniel Mills, have hereunto set my hand
and seal, this Ninth day of May, in the year of our Lord One thousand
eight hundred and seventy-eight.
Witness,
EDWIN P. ALEXANDER,
Consulting Engineer and Patent Agent,
14, Southampton Buildings,
Chancery Lane,
W.C.
DAN. MILLS. ·(L.S.)