Improvements in the Construction of Knife-edges and Bearings of Scale Beams or Weighing Machines.
Year: 1890

page_text: Date of Application, 25th Jan., 1890
Complete Specification Left, 27th Oct., 1890-Accepted, 10th Jan., 1891
PROVISIONAL SPECIFICATION.
Improvements in the Construction of Knife-edges and Bearings of
Scale Beams or Weighing Machines.
We, WILLIAM BEILBY AVERY and HENRY JOHNSON AVERY, trading as W. & T.
Avery Weighing Machine Manufacturers Birmingham in the County of Warwick do
hereby declare the nature of this invention to be as follows:-
Our invention has for its object to facilitate the construction of knife edges and
their bearings; and to more readily and effectively secure the knife edges to the beams
or other parts of weighing machines or balances, to which they may be required to be
attached.
In carrying our invention into effect we construct a knife edge for attachment to
the beam of an ordinary weighing machine, balance, or scales out of steel bar or
plate and we make the knife edge in triangular form having its base pierced or cut
through to suit the width of the beam or lever to which it is to be secured. Thus
the knife edge sits or rests upon the beam or lever; and by reason of its recessed
portion embraces the beam or lever while the recess within the beam itself is covered,
or protected by the portion of the knife edge base which projects beyond each side of
the beam. The beam or lever we arrange to receive our improved knife edge, by
forming the portion which is to immediately attach to the knife edges with a slightly
undercut or recessed surface upon each side, so that when the knife edge recess has
passed over the beam or lever we burr or force down the metal, so that it becomes
rivetted over upon the side surfaces of the knife edge, and thus effectually secures the
one to the other. The recess within the knife edge itself prevents movement along
the metal of the beam or lever, that is, all tendency to slide is obviated, while the
burring or closing down of the metal of the beam or lever so that it may become
rivetted to the knife edge, prevents any tending to fall out in a vertical direction.
Sometimes we form the hole which is to receive our improved knife edge, having
an undercut or tapered surface so that the knife edge can be slipped into its position,
that is to say we make the base of the hole to suit the base of the knife edge, and
we afterwards burr or force down the metal of the beam to fill in and close up the
recessed central portion of our knife edge and thus rigidly and firmly secure one to
the other,
When adopting the latter arrangement of construction we do not of necessity
make the recess with its width equal to the width of the beam or lever; but simply
provide sufficient recess for the purpose of receiving the burred down metal of the
beam or lever. In this arrangement also we are able to ensure that there shall be no
movement in any direction, of the knife edge within the beam or lever.
The links or suspension members of weighing machines, balances, or scales, we form
with our improved supports for receiving the knife edges upon the lever or beam
which we construct in the following manner :- -We provide an inverted angle bar of
steel or other suitable material which we arrange with its edges upwards to receive
the pointed or knife edge upon the beam or lever. This inverted angle bar we make
with its ends pierced or cut through in order that it may be held between the sides or
frames of the suspending link.
We prevent these angle bars from becoming detached from the links, by placing
pegs or pins immediately beneath the portions of the bars which embrace the sides of
the links. Sometimes we construct these knife edge supports by forming them out of
curved instead of angle bars adopting the same system of attachment as when
employing angle bars as before described.
Dated thin 94th day of Tanu 1900
MARKS & CLERK,
13, Temple Street, Birmingham, Agents for Applicants.

page_text: COMPLETE SPECIFICATION.
Improvements in the Construction of Knife-edges and Bearings of
Scale Beams or Weighing Machines.
We, WILLIAM BELLBY AVERY and HENRY JOHNSON AVERY, trading as W. & T.
Avery, Weighing Machine Manufacturers, Birmingham, in the County of Warwick,
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 has for its object to facilitate the construction of knife edges and
their bearings; and to more readily and effectively secure the knife edges to the beams
or other parts of weighing machines or balances to which they may be required to be
attached.
In carrying our invention into effect we construct a knife edge for attachment to
the beam of an ordinary weighing machine, balance or scales out of steel bar or plate
and we make the knife edge in triangular form having its base pierced or cut through
to suit the width of the beam or lever to which it is to be secured.
Thus the knife edge sits or rests upon the beam or lever; and by reason of its
recessed portion embraces the beam or lever while the recess within the hean itself is
covered or protected by the portion of the knife edge base which projects beyond
each side of the beam. The beam or lever we arrange to receive our improved knife
edge, by forming the portion which is to immediately attach to the knife edges with
a slightly undercut or recessed surface upon each side, so that when the knife edge
recess has passed over the beam or lever we burr or force down the metal, so that it
becomes rivetted over upon the side surfaces of the knife edge and thus effectually
secures the one to the other. The recess within the knife edge itself prevents move-
ment along the metal of the beam or lever, that is, all tendency to slide is obviated,
while the burring or closing down of the metal of the beam or lever so that it may
become riveited to the knife edge, prevents any tendency to fall out in a vertical
direction.
Sometimes we form the hole which is to receive our improved knife edge having
an undercut or tapered surface so that the knife edge can be slipped into its position,
that is to say we make the base of the hole to suit the base of the knife edge and we
afterwards burr or force down the metal of the beam to fill in and close up the
recessed central portion of our knife edge and thus rigidly and firmly secure one to
the other.
When adopting the latter arrangement of construction we do not of necessity make
the recess with its width equal to the width of the beam or lever; but simply provide
sufficient recess for the purpose of receiving the burred down metal of the beam or
lever. In this arrangement also we are able to ensure that there shall be no movement
in any direction of the knife edge within the beam or lever.
The links or suspension members of weighing machines, balances or scales, we form
with our improved supports for receiving the knife edges upon the lever or beam
which we construct in the following manner :- We provide an inverted angle bar of
steel or other suitable material, which we arrange with its edges upwards to receive
the pointed or knife edge upon the beam or lever. This inverted angle bar we make
with its ends pierced or cut through in order that it may be held between the sides or
frames of the suspending link.
We prevent these angle bars from becoming detached from the links by placing
pegs or pins immediately beneath the portions of the bars which embrace the sides of
the links.
Sometimes we construct these knife edge supports by forming them out of curved
instead of angle bars adopting the same systein of attachment as when employing
angle bars as before described.
In order that our invention may be more readily understood, we append hereunto
one sheet of explanatory drawings to be hereinafter referred to.

page_text: Fig. 1 is an elevation of an ordinary beam A for a balance or pair of scales, having
our improved knife edges B attached to it, and having one link C with our improved
knife edge support D, suspended from one end of the beam.
Fig. 2 is a plan of the same.
Fig. 3 is a front elevation of the link plate c, and
Fig. 4 is a side elevation; the knife edge support D¹ being formed out of metal
plate bent into the triangular form; the ends of the supports being cut away at d d'
to form projections for engaging with the sides c¹ c² of the link plate; after the
bearing plate has been placed in its position by a slanting movement we place beneath
the projecting clips d d², pins or screws E to prevent any downward movement of the
support within the link plate the top of the bearing plate being free to rest against
the link plate at c³.
Fig. and Fig. 6 are front and side elevations of the link plate, having our
improved knife edge support constructed in semicircular form.
Fig. 7 and Fig. 8 are enlarged detail views showing the method we adopt for
attaching our improved knife edges to the beams, or to a lever, by rivetting over or
burring down the edges of the metal at a a¹ so as to secure the knife edge firmly to
the beam in any desired position.
The knife edge we recess either as shown in Fig. 9 and Fig. 10 in the form of an
undercut as at 6 or in a plain groove as in Fig. 11 and Fig. 12. In each case the
recessed surfaco permits of a flange or stop being formed on each side of the beam
or lever when the knife edge is placed over and upon or within the beam or lever
thereby preventing movement in the direction of the length of the knife edge while
the rivetting ensures that no movement shall occur in the other direction from the
beam or lever.
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 construction of knife edges and knife edge supports substantially as and
for the purposes hereinbefore described and as illustrated in the accompanying
drawings.
2-The construction of knife edge bearings or supports having two surfaces or
edges formed upon a triangular, or other shaped bent metal plate, with ends cut away
to form flanges or embracing ears to keep the supports in position within a link
plate.
3-The construction of knife edges having a recess cut within the base portion
of the metal, for the purpose of forming retaining shoulders or flanges when placed
within or upon a lever or beam of any weighing machine or balance, substantially
as hereinbefore described and as illustrated in the accompanying drawings.
T
1
1000
MARKS & CLERK,
13, Temple Street, Birmingham, Agents for Applicants.
MARKS & CLERK,
13, Temple Street, Birmingham, Agents for Applicants.