IMPROVEMENTS IN AND IN THE MANUFACTURE OF SLEEPER CHAIRS FOR RAILWAYS
Year: 1882

page_text: LETTERS PATENT to James Mac Lellan Blair of Glasgow in the County of
Lanark Engineer for an Invention of IMPROVEMENTS IN AND IN THE
MANUFACTURE OF SLEEPER CHAIRS FOR RAILWAYS
PROVISIONAL SPECIFICATION left by the said James Mac Lellan Blair at
the Office of the Commissioners of Patents on the 24th August 1882.
JAMES MAC LELLAN BLAIR of Glasgow in the County of Lanark, Engineer,
"IMPROVEMENTS IN AND IN THE MANUFACTURE OF SLEEPER CHAIRS FOR RAILWAYS
""
My improvements have reference to wrought iron or mild steel sleeper chairs
formed more or less hollow on one side and rounded on the other and have for their
object to provide, for general use on railways, sleeper chairs of the class just mentioned
of better quality at less cost.
Heretofore in the manufacture of sleeper chairs the sheets of iron or steel have
been taken one by one in a highly heated state and subjected to high shaping
pressure between dies. The metal has in that way been strained and there have
followed both immediate and subsequent disadvantages; for instance the metal
was, as indicated, subjected to excessive internal weakening strains and consequently
the chairs had a tendency to lose their original form and to rupture; the surfaces
were in a condition to be rapidly affected by atmospheric influences; and the cost
of production was heavy.
Now under my present invention I avoid both immediate and consequent
disadvantages in manner following:-I take the sheets, by preference cold, and
subject them to folding or bending pressure in such manner that there is minimum
forcing at corners bends and turns. And I effect this folding or bending by
pressure on the sheets extending from the centre towards the outer edges or by a
succession of folds or bends care being taken that the dies or appliances leave the
metal at every corner, bend, or turn free to adapt itself to the adjacent foldings or
bendings yet without internal objectionable strains in the metal,

page_text: In carrying my invention into practice in making say such a sleeper chair as is
covered by British Patent N° 3990 of the year 1875, I take one or more sheets cold
and place them in any suitable machine and fold over the sides and ends by
pressure leaving the junction corners or spaces to accomodate themselves to the
adjacent folding or bending pressure. A better chair is obtained in that way as
regards strength and durability and the surfaces of the sheets are not damaged.
The dies or fashioning pieces may be one half stationary and the other half
movable, or otherwise arranged, but in all cases no matter whether operated by
steam or other power, so adjusted that the main portions are duly formed or bent
without objectionable force at the corner or junction portions.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said James Mac Lellan Blair in the Great Seal Patent Office on the
24th February 1883.
JAMES MAC LELLAN BLAIR of Glasgow in the county of Lanark, Engineer.
"IMPROVEMENTS IN THE MANUFACTURE OF SLEEPER CHAIRS
""
My improvements have reference to wrought iron or mild steel sleeper chairs
formed more or less hollow on one side and rounded on the other and have for
their object to provide for general use on railways sleeper chairs of the class just
mentioned of better quality at less cost.
Heretofore in the manufacture of sleeper chairs the sheets of iron or steel have
been taken one by one in a highly heated state and subjected to great shaping
pressure between dies. The metal has in that way been strained and there have
followed both immediate and subsequent disadvantages: for instance the metal
was as indicated subjected to excessive internal weakening strains and consequently
the chairs had a tendency to lose their original form and to rupture, the surfaces
were in a condition to be rapidly affected by atmospheric influences and the cost of
production was heavy.
Now under my present invention I avoid both immediate and consequent
disadvantages in manner following;-I take the sheets by preference cold and
subject them to folding or bending pressure in such manner that there is no
forcing at corners or quick turns. And I effect this folding or bending by successive
single or double foldings or bendings or by one bending, care being taken that the
dies or appliances leave the metal at every quick turn to adapt itself to the adjacent
foldings or bendings, yet without internal objectionable strains in the metal.
In carrying my invention into practice in making say such a sleeper chair as is
covered by British Patent N° 3990 of the year 1875 I take one or more sheets cold
and place them in any suitable machine and fold over the sides and ends by
pressure leaving the junctions corners or spaces to accomodate themselves to the
adjacent folding or bending pressure. A better chair is obtained in that way as
regards strength and durability and the surfaces of the sheets are not damaged.
The dies or fashioning pieces may be one half stationary and the other half
movable or otherwise arranged but in all cases, no matter whether operated by
steam or other power, so adjusted that the main portions are duly formed or bent
without objectionable force at the corner or junction portions.
That others may readily see types of chairs both longitudinal and transverse such
as are under and are easily formed under my invention I have appended hereto a
sheet of illustrative drawing in which.
Fig 1 is a plan and fig 2 a side elevation of a longitudinal or pot sleeper formed
by folding step by step as mentioned the two sides a being first and simultaneously
or almost simultaneously folded into position and the ends b folded afterwards
together or one after the other whilst the corners c are left free to accomodate
themselves without overstraining.
It will be observed that the folds are at the shoulders of any easy curve, say in
a chair of the size shewn of a radius of about two inches and so that there is no
objectionable strain in the metal at any part. & tie bars.
c rails
Fig. 3 is a plan, fig 4 a longitudinal section, and figs 5. 6 and 7 transverse
sections at the lines A A BB & CC of a transverse s'eeper constructed of sheet
metal folded into the required shape in accordance with my invention and by
preference folded cold.
The various sections serve to show clearly the character of the folds throughout
the body of the sleeper and the freedom of the metal at any point from quick turns

page_text: or bends or curves that might strain the metal or be otherwise objectionable or
undesirable.
Fig 8 is a side elevation of a machine such as might be used for folding sheet
metal blanks into sleeper chairs. g bed plate, h shaping block forming part of the
die or fashioner carried in the bearing i and receiving forward motion by means of
the cam j. k driving gear, 7 spring for holding the rear end of the block / against
the cam n. m folding dies or fashioning pieces pivotted at n to the stationary
bearings forming part of the die and between which and h the plate is held whilst
being folded.
The said dies or fashioning pieces are also jointed at P to the links q.
The links q are connected to the sliding block 1. The sliding block r receives
motion from the cam s. t driving gear. When a metal blank is placed against the
block h and the machine is set in motion the block and the fashioning pieces are
caused to approach each other and say two sides or ends of the metal are folded
into position if provided with two additional folding dies or fashioning pieces at
right angles to those shown on the drawing these latter then act and fold the two
ends and complete the formation of the chair.
It will be observed that the machine may be made with four dies advancing
alternately or that two machines may be used. It will be obvious that my
improved sleeper chairs are suitable for tram and other ways as well as so called
railways.
Having now described and illustrated the nature of the said invention in such
manner that others will be enabled to carry my improvements into effect I
claim-
First. Sleeper chairs constructed without objectionable internal strains substan-
tially as described.
Second. Making sleeper chairs without objectionable internal strains by a
succession of foldings or bindings as by dies rolls or the like as herein described.
In Witness Whereof I the said James Mac Lellan Blair have hereunto set my
hand and seal this twenty first day of February in the year of Our Lord,
one thousand eight hundred and eighty three.
JAS M BLAIR (L.S.)