mprovements in or relating to Devices for the Attachment of Pedal or Crank Pins to Crank Arms.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
mprovements in or relating to Devices for the Attachment of Pedal
or Crank Pins to Crank Arms.
I, JOHN BOYD DUNLOP, of Hazeldene, Ailesbury Road, Dublin, Ireland,
Gentleman, do hereby declare the nature of this invention to be as follows:-
This invention relates to devices for attaching pedal or crank pins to crank
arms.
I form the end of the pedal pin with a conical shoulder and a parallel portion
A portion
on which are cut screw threads preferably of reversed buttress form.
of the hole in the crank arm is tapered to receive the conical shoulder on the pin,
the remaining portion of the hole being formed parallel and tapped to receive
the screw threaded portion of the pedal pin.
According to another arrangement I form the pedal pin with a conical shoulder
and a screw-threaded portion, the threads in this case being preferably of the
usual form. The hole in the crank is tapered from both sides; that is to say
the diameter of the hole about its centre is less than at either end. A conical
nut tapped to correspond with the screw threaded end of the pedal pin and
split, placed in one of the tapered ends of the hole in the crank, the nut being
provided with a projecting stud to engage with the recess in the crank or other-
wise constructed so as to prevent the crank and nut from turning relatively to
each other when the pedal pin is screwed home.
The pedal pin may be provided with suitable flats for enabling it to be gripped
by a wrench for the purpose of screwing it into the end of the crank.
1
1
this 21st day of March 1898.
BOULT & WADT,
Agents for the Applicant.
COMPLETE SPECIFICATION.
5 Improvements in or relating to Devices for the Attachment of Pedal
or Crank Pins to Crank Arms.
I, JOHN BOYD DUNLOP, of Hazeldene, Ailesbury Road, Dublin, Ireland,
Gentleman, 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 devices for attaching pedal or crank pins to crank
arms.
I form the end of the pedal pin with a conical shoulder and a parallel portion
Om which are cut screw threads of reversed buttress form. A portion
of the hole in the crank arm is tapered to receive the conical shoulder on the pin,
the remaining portion of the hole being formed parallel and tapped to receive
the screw threaded portion of the pedal pin.
According to another arrangement I form the pedal pin with a conical shoulder
and a screw-threaded portion, the threads in this case being preferably of the
usual form. The hole in the crank is tapered from both sides; that is to say
the diameter of the hole about its centre is less than at either end. A conical
nut tapped to correspond with the screw-threaded end of the pedal pin and
split, is placed in one of the tapered ends of the hole in the crank, the nut being
provided with a projecting stud to engage with the recess in the crank or other-
wise constructed so as to prevent the crank and nut from turning relatively to
each other when the pedal pin is screwed home.
The pedal pin may be provided with suitable flats for enabling it to be gripped
by a wrench for the purpose of screwing it into the end of the crank.
In the accompanying drawings:-
--
Figure 1 is an elevation partly in section of a pedal pin attachment con-
structed in accordance with this invention.
Figure 2 is a modification.
Towards the end of a pedal pin A I form a conical shoulder B, and on the end
of the pin beyond this shoulder I cut screw-threads C of reversed buttress type.
Between the shoulder and the commencement of the screw-thread is formed an
annular groove D. The hole E¹ in the end of the crank E for the attachment
of the pedal pin is formed conical at one end to receive the conical shoulder B,
the other end of the hole being provided with screw-threads corresponding to
those on the end of the pedal pin. The screw-threads on the end of the right
hand pedal pin are cut right-handed, those on the left-hand pedal pin being
left-hand threads, the threads in the holes in the cranks being of course formed
to correspond. Flats A¹ are conveniently formed near the shoulder B for the
reception of a spanner to enable the pin to be screwed into position. The pin
however may be otherwise constructed to allow of this being done.
In the construction shown in Figure 2 the hole E¹ in the crank E is formed
doubly conical, that is to say tapering from either end towards the centre. The
screw-threads C on the end of the pedal pin may be formed of the reversed buttress
type or ordinary screw-threads may be used as shown in the drawing. A conical
nut provided with corresponding threads and longitudinally split is screwed on
to the end of the pedal pin. The nut F is conveniently provided with pin holes Fi
for the reception of a pin spanner by means of which it is tightened up.
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. In a pedal pin attachment the combination with a conical shoulder and
reversed buttress screw-threads formed upon the end of the pin of a crank with a
corresponding hole in it substantially as described.
2. In a pedal pin attachment the combination with a pedal pin for the right
side of the machine having right hand screw-threads and a conical shoulder
formed on it of a pedal pin for the left side of the machine having left hand
crew-threads and a conical shoulder formed on it and right and left hand cranks
with corresponding holes in them substantially as described.
3. In a pedal pin attachment the combination with a pedal pin having a screw-

page_text: threaded cylindrical portion and a conical shoulder such as 1 of a conical sprie
nut such as F and a crank pin having a doubly conical hole substantially as
described.
31
1808
J. B. DUNLOP.
Boult & Wade,
Agents for the Applicant.