IMPROVEMENTS IN ENDLESS BAND KNIFE MACHINES FOR CUTTING TEXTILE AND OTHER FABRICS AND MATERIALS
Year: 1883

page_text: LETTERS PATENT to Robert Bell Sanson, of Mile End in the County of
Middlesex for an Invention of IMPROVEMENTS IN ENDLESS BAND KNIFE
MACHINES FOR CUTTING TEXTILE AND OTHER FABRICS AND MATERIALS
COMPLETE SPECIFICATION filed by the said Robert Bell Sanson at the Office
of the Commissioners of Patents on the 26th April 1883.
ROBERT BELL SANSON of Mile End in the County of Middlesex
"IMPROVE-
MENTS IN ENDLESS BAND KNIFE MACHINES FOR CUTTING TEXTILE AND OTHER
FABRICS AND MATERIALS."
My Invention relates to improvements in the endless band knives of machines
for cutting textile and other fabrics indiarubber coated and other waterproof
fabrics leather, cork, and other materials, and has for its objects to ensure a cleaner
and truer cut, to render the cutting action more rapid, efficient, and therefore to
economise the power for driving the knife, to enable the knife to cut either forwards
or backwards and consequently to enable the direction of the cut to be reversed
without stopping the machine or turning or reversing the material to be cut,
whereby a considerable saving of time is effected-especially in cutting heavy
materials.
My Invention consists of a double edged endless band knife having its two edges
so indented as to form a succession of long cutting edges inclined at a very acute
angle to the centre line of the blade, the successive inclines being connected
together by short curved or straight edges inclined in the opposite direction to the
aforesaid cutting edges. The form of the cutting edges is somewhat analogous to
very long saw teeth, the direction in which the knife runs however being such that
the cutting action is the reverse to that of a saw, the inclined cutting edges making
long drawing cuts.
I am aware that it has been before proposed to make the cutting edge of a band
knife of a wavy or undulating indented form, instead of being rectilineal as usual,
but the effect of a succession of more or less abrupt curves is to produce chopping

page_text: action which causes the material under operation to present jagged edges, and is
otherwise objectionable. Such knives when undulated or indented along one edge
only, do not run true on the band pulleys at high speeds, and my Invention has
also for its object to improve the tension and running of the band knife, and to
avoid too great a variation in the width of the knife and the formation of weak
places, and this end I accomplish by similarly serrating or indenting both edges of
the knife and alternating the serrations or indentations of the one edge with those
of the other so as to produce a double edged serrated band of approximately
uniform width and strength, which, being alike on its two edges, will run as troe
upon the pulleys as an ordinary parallel straight edged knife.
The accompanying drawing represents the preferred form for the knife. a are a
series of cutting edges inclined at an angle of about 2° to 5° to the centre line of
the blade, the said inclines being connected to one another by short curves 6 more
or less abrupt, or by short straight inclined edges taking approximately the same
direction. The precise angle for the inclines a depends upon the width of the knife
which is itself dependent upon the more or less curved character of the forms to be
cut out by it. The indentations along one edge of the blade alternate with those
along the other edge, that is to say, the most prominent parts of the inclined cutting
edges a along one edge of the blade, are situated opposite about the middles of the
inclined cutting edges a along the opposite edge of the blade, and reciprocally so
as to approximately equalise the width and strength of the blade. The cutting
edges a may be sharpened to a knife edge or to a chisel edge as preferred, and may
be kept sharp by a hand stone held against the knife when running. The edges b
are also sharpened although they do not strictly speaking act as cutting edges. The
direction in which the knife runs relatively to the angle of the cutting edges a
when in the machine, is indicated by the arrow and is the same whichever edge of
the knife is in action. The motion of the knife is so true that flanges are not
required to the band pulleys.
The machine itself may be of any usual or suitable construction and need not be
described. The desired form of knife may be produced by stamping out the
superfluous portions of the metal from a straight edged strip of tempered steel of
the proper width. The edges being thus brought to the form shown, are ground or
sharpened in the usual way, the ends of the strip being united by brazing either
before or after stamping out the edges.
The effect of the inclination of the successive cutting edges a may be compared
to the action of an ordinary straight edge band knife, were the table inclined so
as to make an angle of about 85° to 88° with the cutting edge of the knife. In
this case the material would be presented at an angle to the knife with the effect
of facilitating the cutting action in a remarkable manner, but such a method of
presenting the material to the knife would not be practically possible in cutting
curves in considerable thicknesses of material, as the top and bottom layers would
not be exactly alike, whereas by the intermittent drawing cuts of the inclined
cutting edges a, I obtain an equal or better result unaccompanied by any such
objection, the top and bottom layers of material being cut precisely alike in
all respects.
Having described the nature of my Invention and the manner of performing
the same, I declare that what I claim as new and desire to secure by Letters
Patent is.
1st The construction and employment of an endless band knife with a succession
of long inclined cutting edges à making acute angles with the longitudinal axis of
the knife and connected by short reverse curves or inclines, substantially as shown
and described.
2nd The construction of an endless band knife with a succession of inclined
cutting edges along both sides, those along the one side alternating with those along
the other side, substantially as shown and described.
3rd In a machine for cutting textile and other fabrics and materials, the

page_text: employment of an endless band knife having a succession of inclined cutting edges
at both sides as herein described, the cutting action being produced by the motion
of the knife in the direction relatively to the inclination of the cutting edges,
herein specified.
In Witness whereof I the said Robert Bell Sanson have hereunto set my hand
and seal this twenty fifth day of April, A.D. 1883.