Improvements in and appertaining to the Knife Edges of Weighing Machines and Apparatus.
Year: 1892

page_text: Date of Application, 24th Feb., 1892
Complete Specification Left, 24th Aug., 1892-Accepted, 31st Dec., 1892
PROVISIONAL SPECIFICATION.
Improvements in and appertaining to the Knife Edges of Weighing
Machines and Apparatus.
I, HENRY JOHNSON AVERY, of the firm of Messrs. W. and T. Avery,
Weighing Machine Manufacturers, Digbeth, in the City of Birmingham, do
hereby declare the nature of this invention to be as follows:-
My invention relates to the knife edges of weighing machines and apparatus,
and its object is to fasten into the weighing beam, a bar or piece of knife edge
section uniform throughout, in a simple and effective manner, and at the same time
to form the friction pieces or nibs to regulate the side play of the beam upon its
bearings.
In carrying the invention into effect as applied to a weighing beam, steelyard or
lever, I construct a steel knife edge bar of uniform section throughout, the
external ends of which serve as knife edges, and so I secure that the knife edges
on both sides of the beam are absolutely in line. I prefer to form the upper part of
the section of the said knife edge bar of circular configuration while the lower part
I form of the required knife edge shape. I form in the beam two circular parallel
holes which are so bored as to break into each other. The upper hole is bored at
right angles to the plane of the beam, but the lower hole is slightly inclined or is
reamered out or otherwise formed inclined.
The knife edge bar fits accurately in the upper hole with its triangular or knife
edge part projecting into the lower hole. Into the lower hole I fit a short circular
key piece cut out on its upper side to fit the triangular or V section of the knife
edge bar, and on driving this key piece home the continuous knife edge bar is held
firmly in position. In this manner the continuity of the opposing knife edges is
absolutely assured and the knife edge bar is securely held in place truly at right
angles to the plane of the weighing beam. The two holes are preferably arranged
at such distance centre to centre that each hole is complete for more than a semi-
circle before breaking into the other and so both the knife edge bar and the key
piece are held within surfaces greater than a semicircle.
The ends of the key piece are rounded or bevilled and are caused to project on
both sides of the beam or may be left flattened and flush with the sides of the
beam to form the friction pieces or nibs for regulating the play of the beam
laterally.
Dated this 23rd day of February 1892.
MARKS & CLERK,
13, Temple Street, Birmingham, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and appertaining to the Knife Edges of Weighing
Machines and Apparatus.
I, HENRY JOHNSON AVERY, of the firm of Messrs. W. and T. Avery Limited,
Weighing Machine Manufacturers, Digbeth, in the City of Birmingham, 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 :-
My invention relates to the knife edges of weighing machines and apparatus,
and its object is to fasten into the weighing beam, a bar or piece of knife edge
section uniform throughout, in a simple and effective manner, and at the same time

page_text: to form the friction pieces or nibs to regulate the side play of the beam upon its
bearings.
Referring to the accompanying sheet of drawings :-
Figure 1 is an elevation of part of a weighing beam showing my improvements.
Figure 2 is a transverse section.
Figure 3 is an elevation similar to Figure 1, but showing the apertures cut in
the beam to receive my knife edge and key.
Figure 4 is a side elevation of my key piece.
Figure 5 is an end elevation of Figure 4.
In carrying the invention into effect as applied to a weighing beam, steelyard or
lever, I construct a steel knife edge bar A Figures 1 and 2 of uniform section
throughout, the external ends of which serve as knife edges, and so I secure that
the knife edges on both sides of the beam are absolutely in line. I prefer to form
the upper part of the section of the said knife edge bar A of circular configuration
while the lower part I form of the required knife edge shape as shown at Figures 1
and 2. I form in the beam two circular parallel holes a, b Figure 3 which are so
bored as to break into each other. The upper hole a is bored at right angles to
the plane of the beam C but the lower hole is slightly inclined or is reamered out
or otherwise formed inclined. This is clearly shown in the section at Figure 2.
The knife edge bar A fits accurately in the upper hole a with its triangular or
knife edge part projecting into the lower hole b. Into the lower hole b I fit a
short circular key piece B, Figures 1, 2, 4 and 5, cut out on its upper side to fit
the triangular or V section of the knife edge bar A as shown at Figure 5, and on
driving this key piece B home the continuous knife edge bar A is held firmly in
position. In this manner the continuity of the opposing knife edges is absolutely
assured and the knife edge bar A is securely held in place truly at right angles to
the plane of the weighing beam C. The two holes a, b are preferably arranged at
such distance from centre to centre respectively c, d, Figure 3, that each hole is
complete for more than a semicircle before breaking into the other and so both
the knife edge bar and the key piece are held within surfaces greater than a semi-
.circle. This is clearly shown at Figure 3.
The ends of the key piece B are rounded or bevilled as shown and are caused to
project on both sides of the beam (as shown or may be left flattened and flush
with the sides of the beam to form the friction pieces or nibs for regulating the
play of the beam laterally.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The improved arrangement of knife edge bar and key piece as applied to a
weighing beam substantially as hereinbefore described and illustrated in the
accompanying drawings.
2. In a weighing beam, the combination of a knife edge bar as A with a key
piece as B both knife edge bar and key piece being of part circular configuration
and fitting together in circular holes breaking into each other, substantially as
hereinbefore described and illustrated in the drawings.
3. In a weighing beam, the use of a key piece adapted to perform the functions
of friction pieces or nibs to regulate the side play of the beam upon its bearings.
Dated this 23rd day of November 1892.
MARKS & CLERK,
13, Temple Street, Birmingham, Agents for the Applicant.