IMPROVEMENTS IN MACHINERY OR APPARATUS FOR BENDING OR STRAIGHTENING METAL PLATES
Year: 1862

page_text: PROVISIONAL SPECIFICATION left by Hugh Donald at the Office of
the Commissioners of Patents, with his Petition, on the 23rd October
1862.
I, HUGH DONALD, of the Firm of Craig and Donald, of Johnstone, in the
County of Renfrew, North Britain, Engineer, do hereby declare the nature
of the said Invention of "IMPROVEMENTS IN MACHINERY OR APPARATUS FOR
BENDING OR STRAIGHTENING METAL PLATES," to be as follows, that is to say :-
This Invention relates to the arrangement and construction of machines or
apparatus for bending or straightening the metal plates' used in ship-building,
and for other generally similar purposes
Under one modification the machine consists of a pair of cast-iron end
standards connected by horizontal tie rods. Each end standard is made with
a rectangular opening in it, the vertical faces of which are grooved to receive
a sliding block. These blocks carry the bearings of a heavy roller, which in
machines of the ordinary kind serves as the bending roller, but in this modifi-
cation it is not used for that purpose. Below this roller is arranged another
roller of smaller diameter, which is used for the bending of the plates; this
roller being of comparatively small diameter, plates can be circled to a much
smaller diameter than can be accomplished with the ordinary bending
machines. This improvement is very advantageous for bending mast plates or
other similar forms. The small roller is arranged to work in frictional
contact with the upper roller, and this arrangement prevents it springing when
bending heavy plates. Below the smaller roller are arranged two other

page_text: rollers parallel to each other, their peripheries extending out beyond the
smaller roller. These rollers are driven by means of suitable gearing, and
they serve to guide and carry the plates in either direction under the bending
roller. The peripheries of the pair of rollers are indented or grooved longi-
tudinally, one face of the indentation forming a vertical line, whilst the other
is bevelled off until it merges into the periphery of the roller. With this
arrangement when a plate is passed into the machine to be bent its front edge
glides into one of the indentations without the noise or shock which takes
place when the grooves have two vertical faces, as in the ordinary arrange-
ment. The bending roller is fitted on two moveable bushes, so that by
removing these the bending roller is lowered, and its periphery then rests on
the pair of grooved rollers beneath. In this position the bending roller and
the upper roller may be used for straightening plates. The distance between
the two rollers is regulated by causing the sliding blocks which carry the
upper roller to traverse up or down. Each sliding block is fast to a screw
which works in an internal screw formed in the upper part of the end
standard. The screw extends out beyond the end standard, and carries at its
upper part a spur wheel, and to the extremity of the screw is attached a lever
and counterweight, which partly counterbalances the weight of the upper
roller. In a bracket extending out from the framing is carried a spindle
having a hand wheel on its lower end, and at the upper a pinion which gears
with a spur wheel carried on a stud projecting up from the standard. The,
boss of this wheel forms a long pinion which gives motion to the wheel
on the screw and admits of its traverse in the vertical direction. With this
arrangement the position of the upper roller is readily adjusted by turning the
hand wheel so as to suit plates of different thicknesses, which are straightened
by passing them through the rollers when the machine is in motion. The
arrangement of the lever and weight tending to relieve the weight of the
upper roller and admit of its being easily raised or lowered.