Year: 1897

page_text: I, ROBERT FREDERICK HALL, of 154, Sherlock Street, in the City of Birmingham,
Manufacturer, do hereby declare the nature of this invention to be as follows:-
This invention relates to mechanism for adjusting the drive chain of cycles.
The method now in general use is known as the swing back adjustment and
consists in flattening the ends of the chain stays, and the seat stays and slotting out
the former and then passing the rear wheel axle through the holes in the flattened
ends of the seat and chain stays and tightening same together with a nut. The
adjustment is effected by a draw bolt which serves the purpose of a washer on the
axle, and is solid with a screwed tail end which is drawn up by a nut.
By loosening the nut on the axle the washer or draw bolt is drawn backward to
the desired distance, thus increasing the distance between the rear axle and the
crank wheel, after which the adjustment is locked by screwing up the nut on the
end of the axle.
Modifications of this are also used in which the seat stay is fastened to the chain
stay, without being connected to the rear axle.
It will be clear that in the swing back adjustment it is necessary, when remov-
ing the axle, to disconnect the seat stays, where they are held at the seat lug so
that they may permit of the axle and the rear wheel being withdrawn from the
slots of the chain stays.
The fact of making the seat stays a detachable portion of the frame simplifies
the construction of same, but, as this said rear portion of the frame is to negotiate
all the strains brought about in the propulsion of a machine and by the weight
of a rider, including both tension, compression and side strains, it has been found
that the flattening the ends of the tube interferes with the rigidity that is necessary
at this portion of the frame. This has led to the introduction of forgings in the
place of the flattening of the ends of the tube on the fork end but the chain adjust-
ment portion of a cycle still remains a difficult problem for the manufacturer and
is an unsatisfactory part from an appearance point of view.
According to my improvements the sections of the tubes forming the chain and
seat stays are not in any way weakened or interfered with, and all the advantage
of rigidity gained by the solid fork end is obtained without any ugly appearance
and without the drawback of the undetachable seat stay.
In carrying out my invention I insert in the end of the chain stay a piece of
tube of suitable length, the outer diameter of which is equivalent to the inner
diameter of the chain stay. This is forced for a short distance into the chain stay
and is brazed in that position, thus forming a solid portion with the chain stay, and
causing a shoulder to be formed where the two diameters meet, and then slotted
through about 2" of its length the said slot terminating outwardly in open ends so
that the axle may be withdrawn longitudinally therefrom.
The lower end of the seat stay is brazed to a lug, which may be either a forging,

page_text: casting, or piece of tube, or may be made of sheet metal, the inner diameter of
whose larger portion is the same as the outer diameter of the inserted piece of tube
so that on slipping this portion over the said inserted tube, the two shoulders meet,
and have the appearance of being one piece, said inserted piece being sufficiently
long to project through the lug brazed to the seat stay end. On the projecting
end is screwed a ornamental cap, whose functions are, first, to keep the lug on the
end of the seat stay close up to the shoulder of the chain stay, secondly, to cover
up the ends of the open slot, and thirdly, to serve as a shoulder for a tubular nut
which screws up the chain draw bolt and is so designed that the draw bolt end
does not project beyond the fork end in an unsightly manner.
The draw bolt which is of an ordinary construction is made from a piece of
round steel equivalent in diameter to the inner diameter of the inserted piece of
tube in the chain stay. The end of this bolt is turned down to a suitable small
diameter and is screwed to receive a tubular hollow nut. As the hollow or tubular
nut is about the length of the slot and the reduced end of the draw bolt is of a
similar length, it will be seen that the one can be secreted within the other.
The enlarged end of the draw bolt which fits inside the inserted piece of tube
in the chain stay is drilled transversely, thus allowing the rear axle to pass
through it.
The lug which is brazed to the end of the seat stay has a slot made through its
two sides but not completely through its length, that is to say the tubular portion
of the lug is left perfect at the two ends, whilst the slot reaches to within a short
distance of the same.
From the above description it will be seen that when the lug is fitted over the
inserted piece of tube in the chain stay, and the draw bolt and axle are in position,
with the ornamental cap and tubular nut in place, the appearance presented will
be that of a slot that has no opening at either end.
Between the axle cone (on which the balls of the hub revolve) and fork end, a
half round washer is introduced, having a flat side presented to the cone and the
half round side to fit on to the cylindrical portion of the lug brazed on to the seat
stay. On the outside end a similar washer is fitted, and when the nut on the out-
side is tightened, the lug, the inserted piece of tube in the fork end and the
enlarged portion of the draw bolt are all compressed together in one solid, rigid
joint.
As an alternative to this I may substitute the inserted piece of tube in the chain
stay by a solid piece of metal with a slot machined in it as in the inserted piece
of tube. This would dispense with the enlarged ended draw bolt described, and I
should prefer to employ a bolt having a screwed part of suitable diameter as before
mentioned but terminating in a forked end carrying two half round washers as
part of itself. This forked end would allow slight compression between the two
outside washers in the tightening up of the nut.
My invention is applicable to round, oval, D or any other section of tube.
T
100
I, ROBERT FREDERICK HALL, of 154, Sherlock Street, in the City of Birmingham,
Manufacturer, do hereby declare the nature of this invention and in what manner

page_text: the same is to be performed, to be particularly described and ascertained in and
by the following statement:-
This invention relates to mechanism for adjusting the drive chain of cycles.
The method now in general use is known as the swing back adjustment and
consists in flattening the ends of the chain stays and the seat stays and slotting
out the former and then passing the rear wheel axle through the holes in the
flattened ends of the seat and chain stays and tightening same together with a nut.
The adjustment is effected by a draw bolt which serves the purpose of a washer
on the axle, and is solid with a screwed tail end which is drawn up by a nut.
After loosening the nut on the axle the nut on the tail end of the draw bolt is
rotated, and the said washer or draw bolt is drawn backward to the desired dis-
tance, thus increasing the distances between the rear axle and the crank wheel,
after which the adjustment is locked by screwing up the nut on the end of the axle.
Modifications of this are also used in which the seat stay is fastened to the chain
stay, without being connected to the rear axle.
It will be clear that in the swing back adjustment it is necessary, when remov-
ing the axle, to disconnect the seat stays, where they are held at the seat lug so
that they may permit of the axle and the rear wheel being withdrawn from the
slots of the chain stays.
The fact of making the seat stays a detachable portion of the frame simplifies
the construction of same, but, as this said rear portion of the frame has to with-
stand all the strains brought about in the propulsion of a machine and by the
weight of a rider, including both tension, compression and side strains, it has been
found that the flattening the ends of the tube interferes with the rigidity that is
necessary at this portion of the frame. This has led to the introduction of forgings
in the place of the flattening of the ends of the tube on the fork end but the chain
adjustment portion of a cycle still remains a difficult problem for the manu-
facturer and is an unsatisfactory part from an appearance point of view.
According to my improvements the sections of the tubes forming the chain and
seat stays are not in any way weakened or interfered with, and all the advantage
of rigidity gained by the solid fork end is obtained, without any ugly appearance
and without the drawback of the undetachable seat stay.
Figure 1 of the accompanying drawing represents an end elevation of the back
part of a safety bicycle fitted or provided with a chain adjustment constructed
according to my invention. The cap which secures the parts together is removed
from the right hand side member.
Figure 2 is a side elevation of the said adjustment, and Figure 3 is a longi-
tudinal vertical section of the same upon the dotted liner, Figure 1.
Figure 4 is a transverse section of Figure 1 upon the dotted line ¹, Figure 2
and Figure 5 is a vertical section of Figure 4 upon the dotted line a³.
Figure 6 represents a section of the supplementary fitting to the end of the
chain stay separately, and Figure 7 is a like view of the slotted lug or fitting
which is brazed to and is removable with the lower end of the back or diagonal
seat stay.
Figure 8 represents in section and elevation, the cap which screws into the fork
or chain stay end fitting and serves to retain the back stay lug in position thereon
and also forms a shoulder or bearing for traversing nut of the draw bolt.
Figure 9 represents the said draw bolt with the cap and traversing nut.
The same letters of reference indicate corresponding parts in the several figures
of the drawing.
In carrying out the form of my invention illustrated in the drawings, I insert
in the open rear end a¹ of the chain stay a, a supplementary slotted fitting or piece
of tube a², of suitable length, and of an outer diameter equivalent to the inner
diameter of the said chain stay. This is forced for a short distance into the chain
stay and is brazed in that position, thus becoming a solid portion with the chain
stay, and forming a shoulder a³, to be formed where the two diameters meet. The

page_text: slots a, terminates outwardly in open ends a5, so that the axle 6¹, of the rear wheel
hub b, may be withdrawn longitudinally therefrom.
The lower end c¹ of the seat stay c, is brazed to a lug ², which may be either a
forging, casting, or piece of tube, or may be made of sheet metal, the inner
diameter of whose horizontal portion 3, is the same as the outer diameter of the
inserted piece of tube a², and having closed ended slots c, coinciding with those in
the fitting a¹, so that on slipping this portion with the ends of the axle lying in
the slots, over the said inserted fitting, the two shoulders a³, c, meet, and have the
appearance of being one piece. The after end of the said inserted piece or end
fitting is internally screwed at a6, to receive cap d, whose functions are, first, to
keep the lug on the end of the seat stay close up to the shoulder a³, secondly, to
cover up the ends a5, of the open slots a, and thirdly to serve as a shoulder for a
tubular nut e, which screws up the chain draw bolt f, and which may be so
designed that the draw bolt end does not project beyond the fork end in the
unsightly manner.
The draw bolt, which is of the ordinary construction, may be made from a piece
of round steel equivalent in diameter to the inner diameter of the inserted piece of
tube in the chain stay. The end of this bolt is turned down to a suitable small
diameter to form the tail end f¹, and is screwed to receive the tubular or hollow
nute, which if required may be of about the same length as the openings made in
the sides of the fitting, when placed or socketted one over the other, by the coin-
cident slots, so that the one part can be secreted within the other.
The enlarged end of the draw bolt which fits inside the inserted end fitting a',
of the chain stay is drilled transversely, thus allowing the rear axle to pass
through it.
The slots in the sides of the tubular body part or sleeve of the lug c, do not
extend throughout the whole length of the same but a portion of the metal at each
end of the sleeve is left intact so that the said slots are closed at the end.
From the above description it will be seen that when the lug is fitted over the
inserted piece of tube in the chain stay, the draw bolt heads first having been
placed in the insides thereof, with the holes therein next passed laterally onto the
ends of the axle, and the draw bolt and axle are in position with the ornamental
cap and tubular nut in place, the appearance presented will be that of a slot that
has no opening at either end.
Between the axle cone 63 (on which the balls of the hub revolve) and fork end,
a half round washer q, is introduced, having a flat side g¹, presented to the cone
and the half round side to fit on to the cylindrical portion of the lug brazed on to
the seat stay. On the outside end a similar washer g², is fitted, and when the
nuts g³ on the extreme ends of the said axle are tightened, the back stay end lugs
or sleeves of the inserted tubular end fittings of the chain stays and the enlarged
portions or heads of the draw bolt are all compressed together and form solid,
rigid joints.
As an alternative to this I may substitute the inserted piece of tube in the chain
stay by a solid piece of metal with a slot machined in it as in the inserted piece of
tube. This would dispense with the enlarged ended draw bolt described, and I
should prefer to employ a draw bolt having a screwed part of suitable diameter as
before mentioned but terminating in a forked end carrying two half round washers
as part of itself. This forked end would allow slight compression between the two
outside washers in the tightening up of the nut.
My invention is applicable to round, oval, ☐ or any other section of tube.
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
I claim is:-
1
First. In the chain adjustment parts of cycles, making the connection of the
seat or back stays with the chain stays by providing the said seat or back stays
with tubular lugs or sleeves which socket over, the ends or end fittings of the raid

page_text: chain stays, and are there secured, with the longitudinal gaps of the one part
coming coincident with like gaps of the other for the ends of the hub spindle to
pass through and be adjustable therein.
Secondly. In the chain adjustment parts of cycles as referred to in the preceding
claim, securing the slotted sleeve or lug fittings of the back or seat stays in
position upon the coincidently slotted end fittings of the chain stays by means of
a cap or equivalent, screwing into or upon the outer end of the said chain stay
fittings and also forming a bearing for the nut of the draw bolt, the head of which
lies within the said chain stay fitting, with its bearing hole wherethrough the
spindle passes, being coincident with the slots in the said socketting parts, sub-
stantially as described and set forth.
Thirdly. The general construction, arrangement and combination of the several
parts of cycle chain adjustments substantially as described and set forth.
Dated this 8th day of January 1898.
ROBERT FREDERICK HALL,
By Henry Skerrett,
24, Temple Row, Birmingham, Agent for Applicant.