Improvements in the Construction of Laminated Springs.
Year: 1887

page_text: Date of Application, 21st Jan., 1887
Complete Left, 21st Oct., 1887
Complete Accepted, 22nd Nov, 1887
LROY IDIONAL DICITIATION.
Improvements in the Construction of Laminated Springs.
We, JAMES MITCHELL, of 123, Club Garden Road Sheffield in the County of
York, Spring Manufacturer, and THOMAS NICHOLSON, of 29 Wostenholm Road
Sheffield aforesaid, Gentleman do hereby declare the nature of our said invention for
IMPROVEMENTS IN THE CONSTRUCTION OF LAMINATED SPRINGS to be as follows:-
Our invention relates more particularly to improvements in the construction of
laminated springs in which the plates are made with a central corrugation or transverse
groove on one side and a transverse projection on the other, so that the plates fit one
in another, and thus dispense with the necessity of a central bolt hole and bolt for
holding the plates in position, the said hole being a source of weakness to the spring.
In such springs, the hoop which holds the plates together is prepared with a recess
in the bottom side to receive the transverse projection on the bottom or lowest spring
plate, and to enable this to be passed into the said recess, it is necessary to have the
opening of the hoop larger than is required when it is in position. It is the usual
practice therefore to put the hoop on hot and when in position to "jump" it, or close
it up, and thus there is difficulty in removing the hoop, (except by destroying it) when
occasion requires.
Our invention is to remove such difficulty, by enabling the hoop to be readily
removed from the plates, and to otherwise improve the construction.
In carrying out our invention we do not alter the construction of the plates, nor
the bottom part of the hoop, but we form a recess in the top inner face of the hoop,
so that there shall be a passage or space over the top of a cross bolt or pin, that is
passed through the sides of the hoop and bears against the top plate of the spring in
the corrugation or groove beforementioned.
This space or passage, which for example may be three eighths of an inch in height,
is to receive a cushion or intermediate filling up piece of suitable material being
preferably elastic, (but metal may be used if desired).
When the plates are put together, the hoop is put over the plates while cold, and
when the projection in the bottom plate rests in the recess formed in the bottom of
the hoop, the filling up piece or cushion, (being preferably made of rubber), is passed
between the top plate and the hook, projecting a little on both sides. The edges of

page_text: the rubber are opposite the bolt or pin holes, and to obtain a passage for the bolt or
pin, we insert a tapered pin under the rubber, by which means the rubber is raised
so that the bolt can be passed underneath it from the opposite side of the hoop.
The rubber thus fills up the space before mentioned, between the top plate and the
recessed inside face of the hoop, passing over the bolt or pin in the centre, and by
pressing against the parts mentioned it prevents the entrance of wet which is so
detrimental to the life of springs, and also acts as an elastic cushion between the
plates and the hoop.
When it is desired to take the spring to pieces such as for example to replace a
damaged plate, it is only necessary to take out the bolt, withdraw the cushion or
filling in piece and the plates can be drawn out.
A very suitable cushion can be made by a combination of thin sheet steel or other
suitable metal, and a piece of rubber secured to the metal in any convenient way.
Dated the 20th day of January 1887.
ROBT. F. DRURY,
Agent for the Applicants.

page_text: COMPLETE SPECIFICATION.
Improvements in the Construction of Laminated Springs.
We JAMES MITCHELL, of 123 Club Garden Road, Sheffield in the County of
York, Spring Manufacturer, and THOMAS NICHOLSON, of 29 Wostenholm Road,
Sheffield aforesaid, Gentleman, 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 :-
Our invention refers particularly to improvements in the construction of laminated
or leaf springs, in which the plates are made with a central corrugation or transverse
groove on one side, and a corresponding transverse projection on the opposite side,
so that the plates will fit into one another, and thus dispense with the necessity of a
central bolt hole through the plates which weakens the spring.
In such springs the hoop which holds the plates together, is prepared with a recess
in the bottom internal face, to receive the transverse projection on the underside of
the bottom spring plate; and to enable such shaped plates to be got into position, it
is found necessary to have the opening of the hoop, larger than is required when the
plates are in their place.
It is the usual practice therefore to put the hoop on the plates, in a hot state, and
for the smith to close it up, or contract it by hammering; thus when it is necessary
to remove the hoop for any purpose, (such as to replace a broken plate for example,)
the hoop has to be cut off and thus destroyed.
Our invention is to remove such difficulty and loss, by enabling the hoop to be
readily removed from the plates, and to otherwise improve the construction of the
spring.
And in order that the invention may be clearly understood, we annex a sheet of
drawings illustrating how it is carried into effect; similar letters of reference indicate
similar parts in any of the figures.
Fig. 1, is a top view, and
Fig. 2, is a side elevation of our spring.
Fig. 3, is a view of the underside of same.
Fig. 4, is an enlarged section of the hoop and part of plates taken across the bolt.
Fig. 5, an enlarged section cut in the opposite direction.
In carrying out our invention, we do not alter the construction of the plates from
those already described, that is, they have a transverse groove on the top side, and a
projection on the underside, the bottom part of the hoop is also provided with a
recess to admit the said projection on the bottom spring plate, but in addition to
these features we form a recess or concavity in the upper inside face of the Hoop,
easily seen in Fig. 4.
A is the hoop, B denotes the spring plates, C, the recess or concavity in the bottom
face, and D the recess in the top face of the Hoop.
The groove and the projection on the plates can be most distinctly seen on the top
plate in Fig. 4.

page_text: The opening through the hoop is made sufficiently large to admit the plates being
placed in the required position, and to leave a space above them to receive a crossbolt
and a filling up piece or cushion E.
This filling up piece may be made of solid metal, such as iron, having sufficient
ductility for the purpose, or of an elastic material either alone, or covered with
metal.
When the plates are in position, the filling up piece E, which flat is passed into
the recess, and by means of a tapered drift driven through the bolt hole F, it is
forced into the arched shape shown in Fig. 4.
The drift being withdrawn, the bolt G is passed through the sides of the hoop and
along the groove in the top spring plate and secured by a nut or cotter.
In this position the spring plates are held secure, and cannot become loose, but
when the plates are required to be taken out for any purpose, the bolt is first removed
and then with a flat ended drift and a hammer the making up piece can be driven
out and the plates released.
The making up piece, when made of iron or other suitable metal, acts as a support
to the bolt, and when of rubber or other elastic material it serves to keep out wet,
and forms a cushion between the Spring plates and the top of hoop.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1-The improvements in the construction of laminated springs, substantially as
herein described and illustrated.
2 In the construction of laminated springs such as hereinbefore described, the
method of securing the spring plates in the Hoop, so that they can be readily released,
substantially as hereinbefore described and shown.