Apparatus for Making Crank Shafts.
Year: 1899

page_text: Date of Application, 1st May, 1899-Accepted, 2nd June, 1899
Apparatus for Making Crank Shafts.
A communication from Joux P. HARRINGTON, of No. 4216, Walnut Street, in the
City of Philadelphia, in the County of Philadelphia, State of Pennsylvania,
United States of America, Machinist.
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of Middlesex,
Chartered Patent Agent, 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:-
This invention relates to an improved mechanism for manufacturing crank
shafts, and the object of the invention is to construct crank shafts rapidly and
cheaply and at the same time to avoid cutting or rupturing the fiber of the metal.
The class of crank shafts to which the invention relates comprises those having two
cranks at some intermediate point on the crank shaft and a common crank pin.
The invention will be explained fully in connection with the accompanying draw-
ings in which
Fig. 1 is a side view, partly in section, of a set of dies adjusted to the straight
blank from which the crank shaft is to be formed.
Fig. 2 shows the same dies in the advanced position which they assume to com-
plete the first step in the process of manufacture.
Fig. 3 is a side view showing the dies in position for finishing the crank smaft,
the side dies being removed.
Fig. 4 is a section on the line 4-4, Fig. 2.
Fig. 5 is an end view of the middle die which forms the crank pin, taken from
the line 5-5. Fig. 2.
Fig. 6 is an end view of the dies which give the crank its preliminary shape,
taken from the line 6-6 of Fig. 2.
Fig. 7 is a view of the dies which operate on the edges of the crank to give it
its final shape, taken on the line 7—7 of Fig. 8.
Fig. S is a side view of a finished crank shaft.
With-
Referring to the drawings. A. A. indicate a pair of sockets which receive the
ends of the shaft S upon which the cranks are to be formed. The sockets have
cylindrical openings equal to the diameter of the largest shafts for which the
apparatus is adapted and for smaller shafts cylindrical bushings B are used.
in the bushings are filling blocks which form solid abutments for the ends of the
shafts S. By varying the bushings and filling blocks the sockets may be adapted
to hold shafts of any diameter or length smaller than the maximum capacity of
the sockets. On the inner ends of these socket pieces are the main dies D. The
bushings and the dies D are preferably formed in halves which are separable to
permit the ready insertion and removal of the shaft, the line of division being
vertical, as shown in Fig. 4. This feature. however, is not absolutely essential
as the shaft may be inserted and withdrawn by the endwise movement of the parts
without separating them. Suitable means for operating the sockets and dies D

page_text: are provided, such as pressure pistons or cams, but for the purposes of this appli
cation it is not deemed necessary to illustrate the operating means, such means
being common und well known. The inner faces of the dies D) are at and
parallel and they are used to shape the outside faces of the cranks, as will be
explained hereinafter.
The crank pin is formed by a central die E which is movable at right angles
to the movement of the dies D. This die E is preferably divided vertically, as
shown in Fig. 5. It has a central opening through which the shaft passes, as
shown in Fig. 1, and which determines the size of the crank pin. This opening
is preferably rabbeted at d to form annular shoulders at the ends of the crank pin
as shown in Fig. S. The dies D are similarly rabbeted at to form annular
shoulders on the shaft adjoining the cranks. These shoulders strengthen the
connections between the cranks and the shaft and crank pin.
Adjacent to the die E are a pair of dies F which cooperate with a similar pair
of dies Gadjacent to the dies D to give the crank its preliminary shape, as shown
in Fig. 2. These dies are formed with right angled recesses into which the
metal is upset to form the angles of the cranks. They are also provided with
rounding shoulders i which perform the preliminary bending of the blank, as
illustrated in Fig. 2.
The shaft is suitably heated and the ends are fitted into the suckets A and the
die E is closed upon the portion which is to form the crank pin, as shown in Fig. J,
the dies and occupying the positions shown in that figure. To perform the
first step in the process the shanks A and the dies D and are moved toward each
other and simultaneously the die E and the dies F are moved vertically. The dies G
are prevented from vertical movement and in consequence the parts assume the
position as shown in Fig. 2. During this operation, the metal is upset into the
angles and the corners's of the cranks are formed. At the same time the cranks
are turned up to an angle of about 45 degrees with the shaft and the metal is upset
sufficiently to form the shoulders & adjacent to the cranks.
The dies Fand G are now withdrawn and two pairs of dies equal in thickness
to the cranks and having curved faces are substituted. These dies have a recipro-
cating movement and they form the rounded ends of the cranks. Upon the sides
of each crank, as shown in Fig. 7. are a pair of dies K equal in thickness to the
cranks and adapted to form the edges thereof. The dies K have a reciprocating
movement and they strike the cranks alternately with the dies J.
The second operation in forming the cranks, consists in removing the dies and G
and then giving the die E a further movement until the erank pin is brought to
its proper position and at the same time moving inward the dies to bring the
shaft ends into proper relation with the cranks and to turn the cranks at right
angles to the shaft. This brings the dies D and E into the position shown in
Fig. 8 and while they are held in this position the third operation, which consists
in hammering or pressing the edges and ends of the cranks into shape, is per-
formed by the alternately reciprocating dies and K.
All of the above operations may be completed in a very brief space of time so
that a crank shaft may be finished with a single heating of the blank.
By this improved apparatus the angles of the cranks are formed perfectly and
there is a minimum disturbance of the grain or fiber of the metal. The angles
of the cranks are perfect and the junctions of the cranks with the pin and shaft
are very strong.
Having now particularly described and ascertained the nature of the said inven-
tion as communicated to me by my foreign correspondent and in what manner
the same is to be performed. I declare that what I claim is:-
1. A mechanism for forming from a straight blank a crank shaft having a
double crank and an intermediate pin, comprising means for forcing the crank
pin out of line with the blank and at the same time upsetting the metal to provide
sufficient stock for the cranks and forming the corners of said cranks before they

page_text: are brought into parallel relation with each other, and means for subsequently
bringing said cranks into parallel relation by straightening their intermediate
portions without disturbing their corners, whereby rupture and destruction of the
fiber of the metal are reduced to a minimum.
2. A mechanism for forming from a straight blank a crank shaft having a
double crank and an intermediate pin, comprising means for forcing the crank
pin out of line with the blank and at the same time upsetting the blank to provide
sufficient stock for the cranks and forming the corners of said cranks, means for
subsequently forcing the crank pin to its proper position and at the same time
bringing the cranks into parallel relation without disturbing said corners, and
means for finishing the ends and edges of the cranks.
3. In a machine for making crank shafts, the combination with the sockets for
holding the blank, of the crank pin die E and the opposing dies F, G, substan-
tially as described.
4. In a machine for forming crank shafts, the combination with the sockets for
holding the shaft provided with the side dies D of the crank pin die E, substantially
as described.
5. In a machine for forming crank shafts, the combination with the sockets
for holding the blank, provided with the side dies D. of the crank pin die E and
the reciprocating dies J, K, for finishing the crank, substantially as described.
6. In a machine for forming crank shafts, the combination of the sockets A.
the bushings B, the filling block C and suitable dies for shaping the cranks, sub-
stantially as described.
7. In a machine for forming crank shafts, the opposing dies F, G, having angular
recesses to form the angles of the cranks and the shoulders for partially bend-
ing the cranks, substantially as described.
1
1000