IMPROVEMENTS IN BARRING ENGINES OR ENGINES FOR TURNING LARGE ENGINES
Year: 1884

page_text: Wo, WILLIAM HARGREAVES, and WILLIAM INGLIS, of the Soho Iron Works,
Bolton, in the County of Lancaster, Engineers, do hereby declare the nature of our
said invention for "IMPROVEMENTS IN BARRING ENGINES OR ENGINES FOR TURNING
LARGE ENGINES," to be as follows:-
Our said Invention has for its object to improve the construction of ongines of
the same class and designed for the same purposes as thoso described in the
Specification of Letters Patent granted to us and dated 9 August 1883, N° 3867.
The principal feature of our former arrangements is the automatic disengagement
of the part of the barring engine which acts on the large engine on the latter
acquiring a greater motion than what corresponds to the motion of the barring
engine, and our present Invention comprises an improved and simplified construction
or arrangement for obtaining such automatic disengagement.
In carrying out our present Invention a duplex-toothed wheel or wormwheel-
pinion is arranged to act on a toothed part of the flywheel of the large ongines or
on any convenient toothed wheel of the large engines. The teeth of the duplex-
toothed wheel are shaped like pinion teeth on the sides which act on the large
engines, whilst their other sides are shaped like worm wheel teeth in order to be
acted on by a worm which is fixed on the crank shaft of the barring engine.
The shaft of the worm wheel-pinion has bearings in blocks which are fitted to
slide in guides parallel to the shaft on which the worm is fixed, the extent of sliding
movement provided for, being sufficient for putting the worm wheel-pinion into gear
with or out of gear from the toothed wheel of the large engines. A brake is
arranged for applying a slight frictional resistance to the worm wheel-pinion at the
part opposite to that acted on by the worm; and when it is wished to make
the barring engine act on the large engine, the barring engine is set in motion and
the brake is applied. This causes the worm wheel-pinion to move into gear with the
toothed wheel of the large engines and to turn this wheel. The worm wheel-pinion
keeps in gear as long as the notion of the large wheel is so slow as to offer
resistance; but as soon as the large engine moves of itself with a motion any greater

page_text: than that corresponding to the motion of the barring engine, the worm wheel-
pinion turning faster than what corresponds to the motion of the worm rolls back
along the worm like a pinion rolling along a rack, and moves out of gear from the
toothed wheel of the large engines.
With this improved arrangement the framing of the barring engine is stationary
instead of being arranged to rock like that of the engines described in our earlier
Specification hereinbefore referred to. The parts of our improved engines may be
arranged in any convenient positions; and springs or weights may be applied to
the worm wheel-pinion to give it a tendency to move or keep out of gear.

page_text: Wo, WILLIAN HARGREAVES and WILLIAM INGLIS, of The Soho Iron Works,
Bolton, in the County of Lancaster, Engineers, do hereby declare the nature of
our said invention for "IMPROVEMENTS IN BARRING ENGINES OR ENGINES FOR
TURNING LARGE ENGINES" and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement, that
is to say:
'
Our said Invention has for its object to improve the construction of engines of
the same class and designed for the same purposes as those described in the
Specification of Letters Patent grauted to us and dated 9 August 1883 N° 3867.
The principal feature of our former arrangements is the automatic disengagement
of the part of the barring engine which acts on the large engine on the latter
acquiring a greater motion than what corresponds to the motion of the barring
engine; and our present Invention comprises an improved and simplified construc-
tion or arrangement for obtaining such automatic disengagement.
In carrying out our said Invention a duplex-toothed wheel or wormwheel pinion
is arranged to act on a toothed part of the flywheel of the large engine, or on any
convenient toothed wheel of the large engine, and is itself acted on by a worm on
the crank shaft of the small engine. The shaft of the worm wheel-pinion can slide
in guides parallel to the shaft on which the worm is fixed, the extent of sliding
movement provided for, being sufficient for putting the worm wheel-pinion into
gear with or out of gear from the toothed wheel of the large engine. A brake is
arranged for applying a slight frictional resistance to the worm wheel-pinion at the
part opposite to that acted on by the worm; and when the brake is applied and
the small engine set in motion the worm wheel-pinion is made to move into gear
with the toothed wheel of the large engine; and it remains in gear therewith and
turns the large engine until the increasing speed of the latter so alters the strains
as to make the worm wheel-pinion recede out of gear from it.
In the accompanying explanatory drawings figure, 1, is a vertical section of the
small engine and of part of the toothed wheel of the large engine. Figure 2, is an
end elevation of the worm wheel-pinion and part of the framing of the small engine,
and figure, 3, is a horizontal section corresponding to figure, 1. In these drawings
the same reference numerals are used to mark the same or like parts wherever they
are repeated.
The small engine comprises two cylinders, 4, 5, with their accessories and carried
by a frame, 6, bolted down to a sole plate, 7. The cylinders, 4, 5, are arranged to
act on cranks at right angles on a horizontal shaft, 8, which has keyed on one end
of it a worm, 9. In gear with this worn, 9, there is a duplex-toothed wheel or
worm wheel-pinion, 10, fixed on a short axle or shaft, 11, having journals, projecting
on each side and entered into bearing blocks, 12, fitted to slide in horizontal
guides, 13, formed in or on the sides of the frame, 6. The worm wheel-pinion 10,
is always turned in the direction of the arrow, and its teeth are made with the
sides acted on by the worm, 9, of the usual shape of worinwheel teeth, whilst the
other sides are shaped like ordinary pinion or spurwheel teeth. When the worm-
wheel-pinion, 10, is in the position in which it is shown in figure, 1, it is in gear
with the internally-toothed part, 14, of the flywheel of the large engine (or it
might be any suitable toothed wheel of the large engine) and with the parts in this
position the small engine will start or turn the large engine. Whilst the small
engine acts on or drives the large engine, and until the large engine acquires from
.its own action such a speed as to be no longer driven by the small engine, the

page_text: strains are such as to keep the worm wheel pinion in gear; but on the speed of
the large engine increasing the worm wheel-pinion, 10, tending to turn faster than
the worm is driving it, rolls back along the worm, its shaft, 11, moving back
along the guidos, 13, and it moves out of gear from the flywheel teeth, 14. To
insure that the worm wheel-pinion, 10, will move completely out of gear, springs, 15,
are applied to its shaft, 11.
.
When the worm wheel-pinion, 10, is not in gear with the flywheel teeth, 14, and
when it is wished to make the small engine operate so as to start or turn the large
engino, some frictional resistance is applied to a part of the worm wheel-pinion
diametrically opposite to that at which the worm, 9, acts on it. This may be done
in various ways; but in the example delineated a small brake block, 16, is fitted
in a guide in one side of the frame, 6, and a hand lover, 17, centered on a stud
fixed in the frame, 6, is connected to the brake block, and can be used for forcing
it against the side of the rim of the wormwheel-pinion, 10. A projection, 18, is
cast on the inside of the frame at the other side of the wormwheel-pinion, 10, to
resist the pressure applied by means of the brako block, 16, the wheel being nipped
between the projection, 18, and the brake block, 16. On the frictional resistance
being applied in this way and on the small engine being set in motion, the worm, 9,
causes the wormwheel-pinion, 10, to move into gear with the flywheel teeth, 14, of
the large engine, and to start or turn the large engine.
We do not restrict ourselves to the precise details herein described or delineated
provided that the distinctive feature of our Invention is retained, this being,-tho
combination of a worm driven by a small engine with and directly driving a
worm wheel-pinion having its centre capable of movement parallel to the axis of
the worm and by such movement entering into gear with or receding out of gear
from the toothed flywheel or other wheel of a large engine.
Having now particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed we declare that what
we claim is:-
The combination of a worm driven by a small engine with and directly driving
a worm wheel-pinion having its centre capable of movement parallel to the axis of
the worm and by such movement entering into gear with or receding out of gear
from the toothed flywheel or other wheel of a largo cugino substantially as and for
the purposes herein before described.
Dated this twenty-first day of Octalwr 1884.