Improvements in Knife-edges and Bearings for Facilitating Adjust- ments and the Maintenance of Weighing Apparatus.
Year: 1895

page_text: Date of Application, 5th Feb., 1895
Complete Specification Left, 1st Nov., 1895-Accepted, 25th Jan., 1996
PROVISIONAL SPECIFICATION.
Improvements in Knife-edges and Bearings for Facilitating Adjust-
ments and the Maintenance of Weighing Apparatus.
HENRY CHARLES WALTERS, Mechanician, Qualified Inspector of Weights
and Measures for the Administrative County of West Suffolk, the Weights and
Measures Office at Bury St. Edmunds, do hereby declare the nature of this
invention to be as follows:-
The system is applicable to all (spring balances excepted) weighing apparatus
generally used in trade, as well as to balances of precision, its object or nature is
to reduce to a minimum the necessary skill, the knowledge of the principle, or the
experience, required by workmen in connection with the adjustment and maintenance
of weighing instruments. By this I mean-that weighing instruments constructed
according to this my interchangeable system, or, existing apparatus to which this
my invention may be applied, will, "enable mechanics without any previous
experience in the practice of adjustments and the maintenance of weighing
apparatus, to readily and accurately undertake such work, neither will any
knowledge of the physical principle, or principles upon which the construction of
the weighing instruments herein referred to are based be required," one, if not both
of these essentials, or qualifications being under existing circumstances absolutely
necessary.
66
The knife-edges or centres as they are commonly called, may, according to the
type, form, or construction of the apparatus to which the system may be applied,
"discs" circles or of
be, either straight-lines or curvilinear, namely, tangents, arcs,
any other similar geometrical form. For example. A knife-edge turned on the
periphery of a disc," circle or a knife-edge turned on the inner surface of a circle,
either, would be adaptable as both "duplex" or "multiplex" centres, inasmuch as,
these centres being of a circular form they may be so fitted to an apparatus as
"second-
design or construction may necessitate, to admit say by half a turn of a
knife-edge," or, in a similar manner according to the "length of knife-edge
required may admit a "third" or more "knife-edges." In using the term "discs
I contemplate circumstances in practice upon which the perpendicular "surfaces
of centres of a circular or other multiplex form will have an important connection
in respect to my first claim, viz. : interchangeability.
The bearings may also according to the circumstances stated in respect to the
knifé-edges, and according to the form of knife-edge or knife-edges. adopted, be
either, triangular, square, circular, oblong or elliptical planes; concave or convex
spherical segments, or partial concave or convex spherical segments, straight-linear
or curvilinear V grooves."
The claims of the system are "briefly" as under :—
Firstly. "Interchangeability "of knife-edges, "centres" and bearings of any
type or form of weighing instrument, complete or partial, i.e. the principle centres
"fulcrums" may be interchangeable, and the end-centres may be interchangeable,
or "all" the respective centres and bearings may possess this relationship one with
the other.
Secondly. Interchangeable detachable centres and bearings of a duplex or
multiplex character. By this I mean that centres and bearings may be i them-
sėlvės either duplex or multiplex, i.e. when the knife-edges or bearings have

page_text: through wear and tear become blunt, marked or otherwise deranged thus
necessitating repairs and re-adjustment of the apparatus; the centres and bearings.
of my invention will admit by the act of revolving [as herein before explained with
regard to centres and bearings of a circular or other multiplex form] and without
detaching, of a "second" or more" knife-edges etc., or when any other form is
used of which the actions of reversing or interchangeing may present another
knife-edge or bearing, and when other possible means which any certain form
might allow, and such knife-edges and bearings have served to their fullest intended
extent, they may further be readily detached and substituted by new ones
manufactured to guage, to easily drop into, and be fixed in their right positions;
thus giving these most essential parts of a weighing instrument a double or
multiplex life, as well as finally admitting their renewal without disturbing the
centre of gravity or other principle of construction of an apparatus.
Dated this 4th day of February 1895
Improvements in Knife-edges and Bearings for Facilitating Adjust-
ments and the Maintenance of Weighing Apparatus.
I, HENRY CHARLES WALTERS Mechanician, Qualified Inspector of Weights
and Measures for the Administrative County of West Suffolk, of the Weights
and Measures Office, and residing at Bury Saint Edmunds, 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-edged centres and bearings of weighing
apparatus dependent upon principles of gravitation in connection with principles of
leverage and has particularly for its object to facilitate adjustments and to enable
tlfe maintenance of such weighing apparatus to be carried out with the least amount
of skill, knowledge or experience.
For this purpose, my invention consists, first, of improved means of fixing or
placing the knife-edged centres and bearings in position in a manner which will
enable them to be readily detached for interchanging or renewal, secondly, of
improved means of forming several knife-edges upon the centres of weighing
apparatus and of providing correspondingly in this respect to the bearings, whereby
a new knife-edge or a new bearing can when needed be brought into action with the
least amount of trouble or labor, and, as the accuracy of weighing apparatus
governed by the principles herein referred to is also greatly dependent upon the
degree of perfection of the knife-edges and bearings both, as regards shape, as well.
as regards the physical properties of the material or materials of which they are
made, these means, render practical a systematic production of knife-edged centres
and bearings for weighing apparatus in a complete state, ready for application or
attachment, supplied in forms and sizes as may be best adaptable for any prescribed
type, size or construction of apparatus. Thus, enabling these vital parts of
weighing apparatus to be manufactured to the highest degree of perfection at the
least amount of cost. I carry out the first part of my invention by affixing the
knife-edged centres and bearings "concentrically," in a manner which mainly
involves the arts of turning, milling or slotting as compared with flat surface or
heart-shaped fittings which are either wedged, screwed, driven or drifted
permanently into position and cannot be removed or replaced without involving an
expensive operation of refitting and the re-adjustment of the apparatus generally.

page_text: The second part, I also carry out in a concentric manner, as for instance when I use
a complete circle and the knife-edge is turned either upon the periphery or on the
inner surface, one circular surface serves as a fitting surface concentric to such
multiplex knife-edge. When lengthened and continuous knife-edges are directly
used as compared with the said circular knife-edges I permanently and suitably
provide or attach circular discs or flanges which may accordingly, be at right angles
or parallel to the knife-edges, these flanges fit into corresponding circular recesses
provided for them in a body or beam and form the concentric fittings to the
knife-edges. When circular flanges cannot be conveniently used I obtain the
concentrating effect by using a "spherically curved" fitting surface. Such surfaces
are useful particularly as applied to bearings.
With regard to curvilinear knife-edges and bearings as when for example
a knife-edge is turned round a circle it will be evident that not more than a single-
point of hearing can with advantage be used, the bearing acting merely as a
tangent to the circular knife-edge and, according to the size of the centre a
multiplicity of points can thus successively be brought into action. In practice
however, when constancy of accuracy is needed lengthened or continuous knife-
edges and bearings are preferred.
To obviate the friction which would naturally take place. in lengthened
curvilinear knife-edges and bearings the instant an apparatus began to turn
I insert a friction-centre" the function of which is to prevent the motion taking
place in the curves but around the continuous knife-edge provided upon the
friction-centre. This centre consists of a spherical segment or cup with elongations,
a "slight and sharp" V groove is cut centrally in and across the cup, to correspond
exactly with the curved or circular knife-edge of the primary centre upon which
this segment is readily placed as a cap. The lengthened knife-edge of this friction-
centre is continuous i.e. in the same plane, and is formed upon the said elongations.
When this knife-edge of the friction-centre is required in a line with, or below the
highest point of the curved or circular knife-edge it is necessarily divided, as shewn
by the accompanying drawings in the figures illustrating several applications of
however can be set sufficiently "low" to allow
same; the "primary centres
undivided friction-centre knife-edges to be used if and when required. Thus, the
functions of the primary or circular knife-edged centre being, to govern and to
retain accuracy of leverage as well as to retain and to direct the line of motion in
respect to the centre of gravity of a body or beam.
"
"
The invention will be further described with reference to the accompanying
drawings which illustrate the improvements as applied to various forms of apparatus
and it is to be distinctly understood that although no illustration is shewn to
indicate application to weighing apparatus with differential levers or unequal arms,
it is equally applicable to steelyards as well as to the "bodies" of weighbridges
and the like.
In the drawings,
Figure 1 is a longitudinal view of a fine balance beam fitted with knife-edged
centres according to my improvements.
Figure 2, is an enlarged sectional elevation of the fulcrum centre. Figure 3,
a plan of such fulcrum:
Figure 4 is an enlarged elevation and part section of the adjustable end-centre.
Figure 5, is a plan of same.
Figure 6 is a longitudinal and part sectional view of a body of a weighing
machine provided with circular and multiplex knife-edged centres, shewing an
application of the necessary friction-centre according to my invention.
Figure 7, is a side view, and part section of the body of the machine, shewing
circular centre with suitable bearing as applied,
3
Figure 8, a view shewing the circular knife-edged centre in section, with bearing
as affixed.
A
**
Figure 9, is a part sectional view of that part of the machine viewed from
the front. Figure 10. a plan shewing view of the centres from such position.

page_text: Figures 11, 12 and 13. are respective views shewing a method of affixing an
interchangeable and triplex knife-edged centre as fulcrum to a scale-beam.
Figures 14, 15, and 16, are respective views shewing a circular and inter-
changeable knife-edged centre, friction-centre with suitable shackle with bearings
all as applicable to equal-armed scale beams and steelyards.
Figures 17 and 18, are respective views of an interchangeable and if required
triplex knife-edged centre as adaptable to various well-known scales or machines.
Figures 19 and 20, are respective views shewing a concentrating method of
affixing knife-edged centres of any shape as well as bearings when circular flanges
may not be convenient.
Figures 21 and 22 are respective views of a form of lengthened continuous knife-
edged and "quadruplex" centre.
Figure 23, a view of circular and adjustable knife-edged centre.
Figures 24 and 25 are views of common forms of bearings which may be
rendered interchangeable in manner shewn and described.
=
"
Similar letters of reference indicate similar parts in all the figures.
Figure 1, an illustration shewing application of interchangeable and "duplex
knife-edged centres as applied to bullion balances and the like, the details of which
will be readily understood from Figures 2, 3, 4 and 5. Here, the flanges f of the
centres are parallel to the knife-edges k, and are reversible. In the four holes
formed centrally at R, as shewn in Figure 3, and which are tapered, corresponding
pins P, are inserted, Fig. 2, to ensure the right-angular setting of the knife-edges k
to the beam B, two, and opposite holes are needed at a time but as they are tapered,
two are also provided for the setting of the reserve knife-edge ³, when reversed
and brought into action. An adjustment of leverage Fig. 4, usually provided in
best instruments of this description is readily effected by means of the two capstan
screws C, Figures 4 and 5, passing through the flange f; the pressure of the load
being upon the concentrically fitted spindle h.
Figure 6, illustrates a body of a weighing machine fitted with circular and inter-
changeable knife-edged centres throughout. The fulcrum centres have the knife-
edge turned on the inner surface of the circle, the knife-edge of the end-centres is
upon the periphery. The fulcrum centres bear directly upon the circular and
multiplex bearing b, Figures 7 and 8 but the end centres C, Figure 6, are provided
with the herein before described friction-centre F, Figures 6, 9, and 10.
The fulcrum-centre C, Figure 7, fits into the projection a, of the body B, and is
secured in position by means of the semi-circular clamping-piece Z, which is
provided with the tapered spindle or cone, l, and which passes tangentially through
the groove g, of the centre C; the clamping-piece Z, is attached to the projection,
by providing it with strong pins, r, which are inserted in the body B, and held by
means of the screw S at the flanges Figures 6 and 7. The groovey, in the
centre C, Figure 8, being turned true to the knife-edge k, the centre is by means
of the studs w, and e, Figures 6 and 7, screwed into the projection, as shewn,
accurately secured at any point of its circumference when wedged by the spindle l.
The multiplex bearing 6 in the construction of the figure is pentandrous, the
tapered pin or cone P, necessarily limits the number of positions. The end-centre
bearings b, Figures 6 and 9, consist of simply a circle of steel let into the downward
projections, /, of the ring G, this ring is swung upon pivots t, in order to ensure
the grip upon the knife-edge of the primary centre C.
To the left of Figure 6, details of the primary centre C, as fitting upon the
spindle h, fitted into the body B, are shewn. The face E, is carefully prepared
both as regards distance from the fulcrum as well as with. regard to its angle to
the horizontal, "the line of motion of the machine "the spindle /, passing through
the gap of the body B as clearly shewn in the drawing is screwed, and is provided
with the clamping-nut N, by which the truly turned centre C, is secured against
the prepared face E.
The knife-edge k, niay be thrown on the diagonal as fully represented by
Figure 23, and is thus rendered adjustable, a slot, is provided in the hole of the

page_text: centre into which, the pin i, affixed in the spindle h, fits, Figure 6-thus by means:
of the head of the spindle h, in conjunction with the nut N, a shortening or
lengthening of leverage can be effected.
Figures 11, 12 and 13, illustrate a triplex knife-edged centre suitable for scale-
beams both as end-centres as well as fulcrum-centres, the figures shew the centre
applied as a fulcrum, and generally the tapered pins P, through the flange f, and
the body B, will serve to secure such centres in position; the combination how-
ever indicates a means for adjustment of leverage which in practice will prove to
be desirable and which may be effected thus.-All the pins, P and PA, should be
slackened to allow the centre to be turned slightly more than sufficient in the
direction which may be found necessary, all the pins are then just sufficiently
tightened to take hold-the test is then applied-then in tightening the centre
finally by the pins P, transversely and the pins PA tangentially a delicate and
ready adjustment of leverage can be effected; d, in Figures 12 and 13 indicate
points of contact in side play of each respective knife-edge k. In high-class
apparatus, a tangent screw, instead of tangential cones can be applied for the
purpose.
Figures 14, 15, and 16, illustrate essentially the same combination already
described in connection with Figures 6, 9 and 10, but as applied to equal ant
unequal armed scales where the load is placed below the knife-edges. H, represents.
a suitable form of shackle, with bearings similar to those illustrated by Figures 24.
and 25 applied. The ready method this device affords, i.e. with respect to the
ready means of inserting or applying the "friction-centre," the knife-edge of
which may be varied as to "height" independently in respect to the primary
knife-edge, the advantage of which will in practice be readily understood.
In application of the interchangeable knife-edged centre illustrated by Figures 17
and-18 the points of contact, d, are near the flange of the centre, instead of at the
extremities of the knife-edges, a nut N, is also provided as a means for finally
securing the centre in its recess after fixing by the cone or tapered pin, or pins P.
In Figures 19 and 20 the circular flange is substituted by a square appendage or
mount, which may however be of any convenient shape, provided, it has a spherical
concentrating surface-the cones P may be of any convenient length, screws, with:
or without nuts, may also be applied as indicated.
Figures 21 and 22. illustrate a form of lengthened, continuous and multiplex-
knife-edged centre which is fixed in position upon a spindle in manner as above
described in connection with the friction-centre combination. Four knife-edges k,
are shewn, but the number which may be obtained round a circle will depend upon.
the size of the circle as well as the length required of each knife-edge-e, Fig. 21
is a circular cavity, one each as shewn being central to the knife-edges of the
centre, a pin, to correspond with these cavities is fixed in a body or beam these
ensure the horizontal position (transversely) of each knife-edge respectively when.
brought into action.
The bearings Figures 24 and 25 are fitted easily in their allotted places and are
tightened by means of cones wedged into the tapered grooves y, see application in
Figures 14 and 15.
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. In any weighing apparatus constructed upon principles of gravitation in
connection with principles of leverage, the herein described "interchangeable-
knife-edged centres" for the object and purpose herein set forth. This is effected
by affixing the centres "concentrically" by providing them where and when
necessary with circular flanges or with spherically formed mounts, to fit into or
onto corresponding recesses, cavities or projections provided as the case may be
in a body or beam of a weighing instrument; or, the knife-edged centres are.
concentrically fitted upon spindles. All as herein described and set forth.

page_text: 2. In any weighing apparatus constructed upon principles of gravitation in
connection with principles of leverage, the herein described "interchangeable
bearings" for the object and purpose herein set forth. This is effected by affixing
the bearings of an apparatus in a manner which will enable them when necessary
to be detached and accurately substituted with the least amount of skill and
labour, by providing them with tapered grooves, by means of which with corre-
sponding tapered pins or cones they may be securely drawn or drifted in position.
All as herein described and set forth.
3. The herein described means of providing the said knife-edged centres with
two or more knife-edges, for the object and purpose herein set forth. Which
consists in turning a knife-edge around a circle, either upon the periphery or on an
inner surface or when the knife-edges as shewn are otherwise concentrically formed
upon or within a circle a reserve knife-edge is brought into use by the act of
revolving the centre, and when the concentric flange of a centre is parallel to the
knife-edge or edges, a reserve knife-edge is brought into action by the act of
reversing. All as herein described and specified.
4. The combination of an interchangeable and duplex knife-edged centre,
provided with a circular and concentric flange parallel to its knife-edges, and fitting
into a corresponding recess in the fulcrum part of a balance, all as herein described
and specified.
5. The adjustable combination of an interchangeable and duplex knife-edged
centre, the capstan screws passing vertically through the flange, the concentric
spindle passing centrally and diametrically through the centre, all substantially as
herein described.
6. The combination of a circular knife-edged centre fitted upon a spindle in the
body of a weighing machine as an end-centre and having a knife-edged friction-
centre, the bearing swung upon pivots-all as described and set forth.
7. The combination of a circular knife-edged centre, with the knife-edge turned
on the inner surface, and fitted as a fulcrum centre to the machine as set forth-
the detachable semi-circular clamping piece fitted with a conical spindle for
wedging or holding the centre in position, screwed at the thinner end and passing
tangentially through the groove of the centre, the suitable wheel and axle bearing,
all, as herein set forth and described.
8. The adjustable combination, having tangential cones in addition to the
transverse cones for securing a centre in position-the triplex concentric centre,
all as herein described, and for the purposes specified.
9. The combination of a shackle, shewing common forms of bearings applied in
manner herein described-the primary centre, friction-centre, all as set forth.
10. The quadruplex concentric, continuous knife-edged centre, as herein
described and set forth.
Dated this 31st day of October 1895.
HENRY CHARLES WALTERS,
Applicant.