AN IMPROVED MODE OF SECURING AND FINISHING THE ECCENTRICS ON CRANK SHAFTS OF LOCOMOTIVES OR OTHER NGINES OR FOR ANY SIMILAR PURPOSE WHERE AN ECCENTRIC OR ECICS ARE USED.
Year: 1883

page_text: LETTERS PATENT to Francis Holt of Derby in the County of Derby
"
Engineer for an Invention of AN IMPROVED MODE OF SECURING AND
FINISHING THE ECCENTRICS ON CRANK SHAFTS OF LOCOMOTIVES OR OTHER
PROVISIONAL SPECIFICATION left by the said Francis Holt at the Office
of the Commissioners of Patents on the 5th March 1883.
FRANCIS HOLT of Derby in the County of Derby Engineer.
"AN IMPROVED
MODE OF SECURING AND FINISHING THE ECCENTRICS ON CRANK SHAFTS OF
LOCOMOTIVES OR OTHER ENGINES OR FOR ANY SIMILAR PURPOSE WHERE AN
ECCENTRIC OR ECCENTRICS ARE USED.".
The object of my Invention is to secure eccentrics upon crank shafts without
using keys or other loose pieces.
In performing my Invention I cast the eccentrics or eccentric on the crank
shaft after the shaft has been turned to receive them.
This simple manner of securing eccentrics has many advantages as for instance
In applying my Invention to a locomotive requiring four eccentrics, the number
of loose parts is reduced from forty four pieces to one piece.
Combining the four eccentrics on the crank shaft in one casting makes them
stronger and more reliable.
The first cost of making four eccentrics for a locomotive is reduced by one half
and finally the only operation necessary to finish the eccentrics after they are cast
in their places is to turn the circumference of each.-I accomplish this by securing,
by set screws or otherwise, a disc of metal to each end of the crank shaft and
forming centre holes which correspond respectively with the centres of the
eccentrics to be turned: each eccentric may then be turned on the circumference
by revolving the crank shaft in the lathe on the two centre holes which correspond
with the centre of the said eccentric.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Francis Holt in the Great Seal Patent Office on the 1st September
1883.
FRANCIS HOLT, of Derby in the County of Derby, Engineer. "AN IMPROVED
MODE OF SECURING AND FINISHING THE ECCENTRICS ON CRANK SHAFTS OF
LOCOMOTIVES OR OTHER ENGINES, OR FOR ANY SIMILAR PURPOSE WHERE AN
ECCENTRIC OR ECCENTRICS ARE USED
"
The object of my Invention is to secure eccentrics upon crank shafts without
using keys or other loose pieces.
In performing my Invention I cast the eccentrics or eccentric on the crank shaft
after the shaft has been turned to receive them. This simple manner of securing
eccentrics has many advantages as for instance
In applying my Invention to a locomotive requiring four eccentrics the number
of loose parts is reduced from forty four pieces to one piece.-Combining the four
eccentrics on the crank shaft in one casting makes them stronger and more
reliable.
The first cost of making four eccentrics for a locomotive is reduced by one half
and finally the only operation necessary to finish the eccentrics after they are cast
in their places is to turn the circumference of each. I accomplish this by securing
by set screws or otherwise, a disc of metal to each end of the crank shaft and
forming centre holes which correspond respectively with the centres of the
eccentrics to be turned: each eccentric may then be turned on the circumference
by revolving the crank shaft in the lathe on the two centre holes which correspond
with the centre of the said eccentric.
And in order that my Invention may be fully understood and readily carried
into operation I will proceed to describe the accompanying three Sheets of
Drawings which represent a convenient and reliable mode of carrying my
Improvements into effect reference being had to the figures and letters marked
thereon.
.
The crank is in the first place rough 'turned' on that part where the eccentrics
are to be cast on it and a box pattern is made for moulding the eccentrics in a
separate box.
On Sheet 1.-Fig. 1 is an elevation partly in section. Fig. 2 a plan and Fig. 3
an end view of the apparatus used in the first process of preparing to mould.
a is the base plate on which the mould is built: b is one half of the pattern of
the eccentrics, secured square to the base plate a by the pins 6' and c is the bottom.
half of the moulding box which is held square with the pattern 6 by two pins o²
which rest in holes provided for them in the base plate a: d d are two brackets
fixed on and square with the base plate a for supporting the locomotive crank
while the eccentrics are being cast on it.
Fig. 4 is an end view showing the top half c¹ of the moulding box placed in
position on the bottom half of the box c, with the complete pattern 6 in its place.
The cores for lightening the casting are placed in the mould in the usual way.
On Sheet 2.-Fig. 5 is an end view. Fig. 6 an elevation. and Fig. 7 a plan of
the locomotive crank shaft f showing how the same is placed on the brackets d d'
for casting the eccentrics on the shaft.
In these views the moulding boxes c c¹ are secured to, and rest on a table or
making up piece g which has four screws h, one at each corner, let into the base
plate a, for adjusting the moulding boxes c c against the crank shaft f and to
determine the right position of the mould on the crank shaft: The top part c' of
the moulding box is secured to the bottom one c by the usual pins and cotters.c³
as shown.

page_text: Figs. 8 and 9 are detached views of the eccentric pattern b when together and
showing the dividing line.
After the mould has been set and adjusted on the crank shaft f as explained in
reference to Figs. 5, 6 and 7 the cast iron or other metal can be poured into the
mould to form the eccentrics.
On Sheet 3.-Fig. 10 is a view of the locomotive crank shaft f with the
eccentrics f¹ cast on in their proper position, the crank shaft is supported on centres
in angle brackets bolted to a bed plate: Fig. 11 is an end view of the same in
which the outline of the eccentrics is not shown.
In these views the crank shaft f is supported at one end by a fixed centre i, in
the bracket and at the other end on an adjustable screw centre k in the bracket 7:
the brackets and are bolted to any ordinary bed plate m: in each of these
brackets j and are four guide holes n, through which are drilled the centre holes
in the ends of the crank shaft fat a radius and at an angle corresponding with the
determined stroke and position that each eccentric shall bear to each crank. Each
eccentric may then be turned' on the periphery in any ordinary lathe on the two
centre holes which correspond with the centre of the said eccentric.
Fig. 12 is an end view of the crank shaft showing the holes drilled in the
required position for turning the periphery of the eccentrics. Fig. 13 is a view of
a crank shaft without the eccentrics. Figs. 14 and 15 are enlarged views of the
centre drill which passes through the guide holes n in the brackets j and to drill
the ends of the crank.
Combining the four eccentrics on the crank shaft of a locomotive in one casting
insures greater accuracy; makes them stronger and more reliable by dispensing
with the usual wrought iron back part and the number of loose pieces is reduced
from a maximum of forty four to one piece.
I have described the plan adopted by me for casting and turning eccentrics on
locomotive crank shafts but I wish it to be understood that my Improvements are
applicable for casting eccentrics upon other shafts.
Having stated the nature of my Invention and described a convenient manner
of performing the same
I declare that I claim
1. The improved mode of securing and finishing the eccentrics on crank shafts
of locomotives or other engines or for any similar purpose where an eccentric or
eccentrics are used substantially as herein shown and described.
2. The method of casting eccentrics on the crank shafts of locomotives and other
engines substantially as herein described.
In witness whereof I the said Francis Holt have hereunto set my hand and.
seal this thirtieth day of August One thousand eight hundred and eighty three.
FRANCIS HOLT (LS)