IMPROVEMENTS IN THE WHEELS OF TRACTION AND OTHER CARRIAGES OR, VEHICLES,
Year: 1870

page_text: LETTERS PATENT to William Firth, of Rose Villa, Viewforth,
Edinburgh, in the County of Mid Lothian (Secretary to the
North British Rubber Company, Limited), for the Invention of
"IMPROVEMENTS IN THE WHEELS OF TRACTION AND OTHER CARRIAGES OR,
VEHICLES,"
"..
COMPLETE SPECIFICATION filed by the said William Firth at the
Office of the Commissioners of Patents, with his Petition and De-
claration, on the 20th August 1870, pursuant to the 9th Section of
the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
FIRTH, of Rose Villa, Viewforth, Edinburgh, in the County of Mid
Lothian (Secretary to the North British Rubber Company, Limited),
send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS
IN THE WHEELS OF TRACTION AND OTHER CARRIAGES OR VEHICLES," and have

page_text: petitioned Her Majesty to grant unto me, my executors, administrators,
and assigns, Her Royal Letters Patent for the same, and have made
solemn Declaration that I am the true and first Inventor thereof.
NOW KNOW YE, that I, the said William Firth, do hereby declare
that the following Complete Specification, under my hand and seal,
fully describes and ascertains the nature of the said Invention, and
in what manner the same is to be performed, in and by the following
statement:—
My said Invention relates to improvements in the application and
_construction of compressible and elastic tyres placed outside of the rigid
tires hitherto chiefly in use for the wheels of traction and other carriages,
or vehicles for use on common roads or tramways or railways, or placed
so as to form the treading or road or rail contact surface of such wheels.
Compressible tires have hitherto been constructed either of one con-
tinuous band. or tire of india-rubber or other elastic materials covered
or not with bars or plates of metal to protect such band or tire from
injury from the road. Or they have been constructed of a series of
compressible and elastic felloes or tire segments (composed of elastic
and metallic pieces) suitably linked and bound together, for which
Letters Patent, dated the Twentieth October One thousand eight hundred
and sixty-nine, No. 3059, were granted to me, and to the Specification
of which Letters Patent I now crave to refer, and particularly to the
four special constituents therein set forth as forming the elements of my
Invention.
In now describing my Invention I will first of all call attention to
the principles or mechanical conditions which obtain and which regulate
the use of compressible tires. The primary advantage in the use of
compressible tires is obtained from the normal plane of the road or rail
coinciding with the plane of a segmental line. of the wheel circle and
not with the plane of a tangent line of said circle, as in the case of a
rigid tire.
From this it must follow that if the height of any such
segmental line be one inch, or, what is the same thing, if the amount of
compression be one inch, the extent of road or rail passed over by one
revolution of the wheel will be a little over six inches less than would
have been passed over had the outer tire been incompressible, for, as is
well known, if the diameter of a circle be two inches less than that of
another its circumference will be a little over six inches less. From

page_text: this circumstance alone a continuous flat circular compressible tire, or a
segmental one with the outer surface nearly continuous, will move round
the rigid inner tire in a direction retrograde or opposite to the motion
of the carriage. Hitherto these continuous tires have been made and
used a little less in internal diameter than the external diameter of the
rigid tire over which it is therefore stretched, and the retrogade motion
which must nevertheless take place is not only provided for but retarded,,
and hence much injury results. to the tire and much driving power-is
lost.
One object of my Invention is therefore to provide for the retrogade
motion taking place easily, thereby saving driving power and rendering
the tire less liable to injury. The retrogade motion of the compressiblé
tire may however be prevented provided a contraction or something
equivalent thereto of the uncompressed' surface takes place while being
compressed, for, if the bearing arc or portion of the wheel face bearing
the weight of the carriage at any particular instant can be reduced to'
the length of the segmental line or chord, or the line coinciding with
the plane of the road or rail, the circumferance of the whole circle will
be reduced to the length of the rolling circle of such a wheel.
The prevention of the retrogade motion of these compressible tires
is the second object of my Invention.
.
}
The third object of my Invention is to provide means for easily:
removing the different parts of a segmental tire for repair and replace-
ment, and this I aecomplish. by, making each compressible felloe or tire
segment depend from or between one or more rods or tubes or pins,
secured to or, kept between, the flanges of the wheel, and making one
or, more series of such rods, tubes, or pins perform the additional function
of a rigid tire.
The above-described: principles and objects I make practically and
further effective for the purposes above mentioned by means of the
mechanical arrangements and constructions which I will describe by
reference to the Drawings accompanying these Presents by thic words,
figures, and letters following, that is to say:-
>

page_text: of reference between the set of Drawings accompanying my former
Specification and those accompanying these Presents. And I would also
remark that parts delineated in these Drawings which have like functions
with those shewn and described in the said Drawings accompanying the
said former Specification are marked with the same letters as in that
Specification, that is to say, the bearing pieces have the letter B, the
junction pieces have the letter J, the linking pieces the letter L, and
the treading pieces the letter T, the socket pieces the letter S, and any
combination of these parts have both the letters which singly denote
each constituent of the combination respectively, although certain
Figures, as 1, 2, and so forth are in these Drawings used in conjunction
with the said letters.
Figure 28 represents a segment of my improved wheel tire with the
parts arranged in the following manner:-T1 to T5 are a series of metal
triangular treading pieces, each extending across the wheel face and
filled with cork or wood all through or at each end the sides of these.
treading pieces are carried upwards between the..metal linking bolts Ll.
to L5, and to secure rigidity are bent outwards to form a lozenge or
other formed space into which wood or cork or other suitable material
may be placed. The ends of these treading pieces are then bent a
outwards, so that the complete outline of any one such treading piece
as T1, T1, is an irregularly formed T. Between any two of these
treading pieces as T1, T2, there are the following parts :-(1.) An india-
rubber junction piece J1 continuous across the wheel face; (2.) B1
an india-rubber bearing piece either continuous or in pieces, say three
as shown in cross sectional drawing Fig. 29, the spaces between them
being utilized as air cells if required; (3) a metal linking belt Ll with
its metal covering pipe P1 performing the functions of a linking piece'
and with the other and similar bolts L2 to L5 round to Ln, the function
of the rigid wheel tires hitherto in use (4.) An elastic socketing
piece S by which the treading pieces are hung, and (5), J, B1,
a combined junction and bearing piece of india-rubber acting not
concentrically but tangentially, or like arch keys in resisting the
concentrical compression of the treading pieces N, a nut screwing
on a linking bolt Lm supposed to pass if required through a flange
thickening ring R, (as shewn in Fig. 29) and thereby holding it to the
wheel flanges F, F, F, F, F.

page_text: Fig. 29 is a cross section on the radial plane passing through the
centre of L1, shewing the wheel flanges F and F1 and the compressible
and elastic felloes or tire segments suspended between them by means
of the linking bolts which perform the function of the rigid wheel
tire B, B1, B'1 are the three smaller forming one whole bearing piece
between any two contiguous treading pieces. The spaces between them
I sometimes cover and form into air cells. The combined junction and.
bearing pieces J, B1, may in like manner be formed of one or more
pieces with air cells between them. The several pieces in this arrange-
ment may be variously formed, thus, the treading pieces may be con-
tinuous across the wheel face, or several smaller may be employed to
form one whole treading piece. Further they may each be made about
double the width shewn, and if several shorter be employed to make.
one whole treading piece, and be placed circumferentially and alternately
in advance of each other, the cork or wood filling of T2, for example.
will be common to the shorter but wider treading piece, then occupying
the position of T1 and T2, and to the similar one then occupying the
position of T2 and T3, and of course to all on the same radial planes.
with these, and said filling piece then becomes a socket piece and may
then be made of india-rubber extending across the wheel face or con-
tinuous between the flanges, and may have a metal mandril passing
through it. A great variety of forms might be adopted for the several
pieces, but it will generally be found convenient to make the treading
pieces either narrow and continuous across the wheel face or wider and
shorter or non-continuous and alternating with each other as shewn in.
Figs. 30, 31, and 32.
Fig. 30 represents a segment of my improved wheel tire with the
wheel flanges removed and their position indicated by the dotted line f,
and that of a covering or thickening ring on the left by R, R, which'
may be considered as part of the front flange, and bound thereto by
bolts 6 as shewn in cross sectional Drawing, Fig. 31, T1, T2, T3, are one
series of circular treading pieces placed circumferentially and alternately.
in advance of another series of similar treading pieces T1, T2, T3, TN,
which alternate with another series in the same radial plane with T1,
T2, T3, and so on to the extent required to get any desired width of tire;
in the cross sectional drawing there are five series shown, but any other'
(by preference uneven) number may be employed. Each of these

page_text: treading pieces or felloes, say T1, is suspended or linked by two linking
pieces L1, L2, which in this arrangement are metal bolts or rods or tubes
passing through holes in the wheel flanges and through metal tubes Pl,
P2, placed over them between the flanges. These covering tubes thus
form distancing bars or supports for the flanges by means of nuts N1,
(Fig. 31.) and at the same time allow of the easy removal and repair
or replacement of any of the treading pieces or of the bearing pieces or
other pieces forming the compressible and elastic felloes or tire segments
of my improved tire. The bearing pieces B1, B2, B3, are made of india-
rubber or other elastic material and of any suitable form. In the
Drawing they are shewn cylindrical and are supposed of equal length
with the treading pieces. Any bearing piece as B1 is placed inside of
its treading piece T1, and made to bear against the linking rods L1, L2,
by the covering tubes P1, P2, around the under side of which it will
compress by any concentric radial pressure as when bearing the weight
of the carriage, thus the linking pieces or the linking rods are made
to perform the function or use of a rigid wheel tire by being the fixed
resistances against which the bearing pieces are pressed by the weight
of the carriage. The concentric movement or compression of the
treading pieces on the same radial plane with T2 for example, will
immediately bring the treading pieces T1, T2, and very soon thereafter
the treading pieces T1, T3, and all those on the same radial planes with
them to bear against the plane which may represent the road or rail
surface, thus the road or rail contact will be much greater circum-
ferentially than with a rigid tire and a much higher tractive effect will
be obtained.
Fig. 31 represents a view of my improved wheel tire partly in cross
section taken on the line n of Fig. 30 for the parts between the flanges
and on the radial plane passing through the axis of L' for the flanges and
parts exterior thereto; f, f1, are the wheel flanges, and R, R, the
thickening rings for receiving the linking bolts Ll and the binding
bolts b, secured respectively by nuts N1 and N to said rings or wheel
flanges. The treading pieces and bearing pieces are marked as in
Fig. 30. P, P, is a metal tube placed over the linking bolt L1, and a
similar tube may be used over the binding bolt 6, both tubes acting as
distancing pieces between the flanges.
Fig. 32 represents a scoment of my improved wheel tire with the.

page_text: treading pieces arranged and linked exactly as those described in Fig. 30,
but here the treading pieces are made more rectangular than circular. If
desired the treading pieces may be made more elongated, as indicated by
the dotted lines, and their sides bent outwards or inwards to form spaces
for junction pieces such as the spaces marked J, which may be filled
with combined socket and junction pieces, by which the treading pieces
rest on the bolts or linking rods L1 to L6. The bearing pieces in this as
well as in other forms of treading pieces may be cylindrical, as in Fig. 30,
or elliptical, polygonal, or rectangular, or the spaces (as from the dotted
line S in T2 downwards) may be filled wholly or partially with solid or
cellular india-rubber of any convenient form, and about equal in length
to the length of any treading piece. Further, compound bearing pieces
may be used as shewn in the Figure, where B₁, B₁, B, are about equal
in width and length to, and are carried respectively in or by the treading
pieces T1, T2, T3, while the cylindrical tier of bearing pieces B1, B2, B3, are
or may be made equal in length to the width between the wheel flanges,
or the width of the wheel face. Any one of the bearing pieces B2, for ex
ample, if continuous, forms a bearing piece common to the two contiguous
treading pieces T2 and T), and also to those on the same radial planes
with them. In other respects Fig. 32 corresponds with Fig. 30, therefore
a cross sectional view is clearly indicated by Fig. 31, already described.
Fig. 33 represents a segment of my improved wheel tire partly in
section, wherein I employ a series of triangular or suitably formed metal
troughs M suspended from the linking rods L4, L5, L6, L7, towards the
centre of the wheel, forming a sort of ground rocking or vibrating rigid
tire suspended from the linking bolts. These are or may be wholly or
partially filled with wood, cork, or any suitable material (W) resting on
the linking rods, and thereby keeping the troughs in position. With
triangular troughs there will be triangular spaces. formed between them,
in which I place triangular combined india-rubber junction and bearing
pieces J4, B4, J5, B5, J6, B6, extending along with the troughs nearly
across the width of the wheel face. These bearing pieces may be linked
together in any suitable manner, and thereby retained between the
troughs or they may be held by the treading pieces T4, T5, T6, which for
this purpose are made longer than the width between the flanges and
have their ends bent towards the wheel centre, and each pierced by an
oblong hole or slot, through which the linking bolts L4, L5, L6, pass,

page_text: as shewn in the Drawing, particularly at T6, where the shaded part
clearly indicates the formation of the ends of such treading pieces.
Their bent up ends are placed between the wheel flanges, as shewn in
Fig. 34, and the linking bolts are passed through the holes or slots
therein, and also through the wheel flanges to which they are secured by
nuts N and N1, Fig. 34. The treading pieces are thus kept to the face
of the wheel, and with them the bearing pieces in the grooves or spaces
between the metal troughs. The ends of the treading pieces may be
made to extend as far as the tops D of the troughs or beyond them, as
shewn by the dotted lines extending from T1, T2, and pierced with a
second round or oblong hole or slot, through which a tube or rod d, as
in Fig. 31, is made to pass. If not required for binding, the wheel
flanges this second series of linking rods may be made a little shorter
than the width between the flanges and free to move up and down
between them from the troughs in which they are made to rest,
when the treading pieces which they link are not bearing on the road
or rail. In this case it will be convenient to cover these rods, or
tubes at intervals with india-rubber tubes S, acting as socketing pieces
and to make the holes in the ends of the treading pieces circular to
receive the metal rods or tubes. By such means the treading pieces may
be bound with any degree of tightness to the bearing pieces. The
linking rods L1, L2, L3, will by such an arrangement act as guides for the
treading pieces by means of the slots in their ends, as already described.
Again, the second series of linking rods may pass through or form a
mandril through the wood, cork, or other filling in the troughs, and it
will then be convenient to extend the slots so as to embrace both series of
linking rods, or the wood or other filling may be dispensed with, and the
spaces inside the troughs left free for the concentric motion of the
second series of linking bolts which are made to rest on the first series
when not at the bearing part of the wheel. Further, the second series
of linking bolts may be linked together by a double series of flat links
on either side, each link as Z of one series embracing two bolts and alter-
nating with the links Z1 of the next series. Each of the two holes in
such links is made large enough to embrace the linking bolt covered with
a piece of india-rubber tube or socketing piece S. Lastly, the bearing
pieces may be formed and shaped as thus,
And the spaces
between the troughs of a similar shape by bending inwards each side so

page_text: various forms of treading pieces being used. The spaces between the
linking bolts and the inside of the treading pieces if blocked up at each
end by a suitably formed piece of india-rubber will convert said spaces
into air cells, in which the air will be compressed by the expansion of
the. bearing pieces into such spaces (as between L5, T5, when compressed:
by the weight of the carriage.
:
.
Fig. 35 represents a cross sectional view of my improved wheel tire
constructed to carry out the first object of my Invention. E represents.
the outer compressible and elastic tire whether constructed of a continuous
or homogeneous band or of a series of compressible and elastic felloes or
tire segments linked together. Inside of the tire E I place one or more
rings, hoops, or bands, or washers, R to R4, a little larger or to any
required extent larger in internal diameter than the outside diameter
of the rigid tire W, and formed of metal or other material sufficiently.
rigid to keep the compressible outer tire E eccentric to the wheel or
to the rigid wheel tire W. These rings I place apart, and between
them similar but thicker rings or bands, or pieces of india-rubber or
other clastic material (1, to t4, having their outside diameters about
equal but their inside diameters either less or greater than the inside
diameters of the rigid rings. If the inside diameters of these elastic
rings be less than those of the rigid rings, as in the Figure, I employ
a smooth faced rigid inner tire W, but if less I employ a rigid...
inner tire grooved circumferentially or formed of a series of narrow
rigid tires, each about equal in width to the width of the elastic*
rings, so as to move with them between the rigid rings R, R1, R2, R3,
R4, the inner edges of which extend respectively to 1, 2, 73, 74, as;
shown by dotted lines. By either. arrangement the pressure from the
outside tire E is communicated by the elastic rings tl, to t4, to the.
rigid tire or tires of the wheel, while at the same time the said rigid'
rings lift the compressible and elastic and therefore flexible tire E over
the upper part of the wheel, (w Fig. 36) and thus keep the elastic tire E
eccentric to the wheel. Further these rigid rings and elastic rings or
pieces may be pierced with a series of holes parallel to the face of the:
wheel, and coinciding when the rings are placed together, through.
which holes, bolts or tubes of metal bor other rigid material are passed:

page_text: and kept in position by and between the wheel flanges, which flanges
form as herotofore assumed parts of the sides of the wheels being rigidly
attached thereto. I sometimes however prefer to have the flanges
loose and free to move round the wheel, and in this case I form the
bolt with heads b¹ and pass them through and secure them to the
flanges by nuts or otherwise, and thus make. the flanges. move in a
retrograde motion with the compressible tire E, round the wheel, to
which also the flanges are thereby kept eccentric, and thus with that
tire form a grooved way continuously laid by the revolution of the wheel
and into which it runs when the carriage is in motion. If it be desired
I cut ordinary wheel teeth round the inner edges of the rigid rings R,
and R4, extending for that purpose. to r and 24 respectively where the
teeth are formed and where said rings gear into the sides G and G4 of
the wheel, which for that purpose are cut. with suitable teeth to gear.
with those in the rigid rings as they successively pass under the wheel.
Where the compression of the elastic tire E. brings the teeth at r, and r4,
respectively into contact, and gear with the teeth at G and G4. The:
other rigid rings may be similarly geared if required.
Fig. 36 is a diagram illustrative of the action of the rings above
described with reference to Fig. 35. Q may be taken to represent the 2
tire including the rings and rendered eccentric by the rings to the
wheel circle which is represented by the heavy circular line w.
The top
of the rigid wheel is supposed to be at w. In using linking bolts instead
of a rigid wheel tire I sometimes prefer to carry only every alternate
bolt through the flanges of the wheel or to leave every alternate bolt 2
free to move up and down between the flanges..
99.
Having now particularly described and ascertained the nature and
object of my said Invention and in what manner the same may be
performed or carried out in practice I hereby declare that I claim the
Invention of "Improvements in the Wheels of Traction and other ;
Carriages or Vehicles as in this present Specification herein-before
described and particularly the use of rigid rings, of and for the purposes
described with reference to Figs. 35 and 36, as applicable not only to
segmental compressible tyres but to any other kind of compressible tyres
in order to accomplish the herein described first object of my Invention a
And I likewise claim the use of bolts as a substitute for the rigid tyres.
hitherto in use so that parts of the bearing pieces or parts of the junction'

page_text: pieces and parts of the treading pieces may be placed between these
fixed resistances and the centre of the wheel, in order to accomplish
those objects of my Invention which I have herein-before termed the
second and third objects of my said Invention; and I also claim the use
of such bolts or pins in conjunction with rigid troughs or links of any
convenient shape free to vibrate or rock thereon as herein described
with reference to Figs. 33 and 34 of the accompanying Drawings.
In witness whereof, I, the said William Firth, have hereunto set
my hand and seal, this Twenty-eighth day of July in the year
of our Lord, One thousand eight hundred and seventy.
Witness,
THOMAS MORGAN,
Secretary to the
Inventors' Patent Right Association, Limited,
21, Cockspur Street,
Charing Cross.
W. FIRTH. (L.S.)