Improvements in Scale-beam Centres and Bearings.
Year: 1891

page_text: Date of Application, 2nd May, 1891
Complete Specification Left, 1st Feb., 1892-Accepted, 12th Mar., 1892
PROVISIONAL SPECIFICATION.
Improvements in Scale-beam Centres and Bearings.
I, CHARLES HENRY BARTLETT of 2, and 3, Welsh Back, Bristol, in the
County of Gloucester, Weighing Machine Manufacturer, do hereby declare the
nature of this invention to be as follows:-
My invention relates to the centres and bearings of scale-beams, and has
particularly for its object to facilitate "lining off" and enable true and perfect
knife-edges to be obtained with the least possible amount of labor.
For this purpose, I provide improved means of fixing the steel knife-edges in
position on the beam, and also improved means of centreing or steadying the
bearings laterally upon the knife edges.
According to my invention, the knife edge is formed on a plate of steel which
is fixed transversely across a slot in the scale-beam by its bevelled side edges
being received in corresponding grooves in the sides of the slot, the said knife-edge
plate being secured firmly in position by a set-screw.
In order to keep the bearing truly central between the sides of the slot in which
the knife-edge is fixed, a dovetail-shaped central notch is made in the knife-edged
plate, and a steel steadying plate is fixed in the bearing in a vertical plane at right
angles to the knife-edge, so that the said plate, which projects across the V-groove
of the bearing, will intersect the knife-edge and pass and fit between the two
steady points formed by the angles of the knife-edge with the sides of the dovetailed
notch.
In the case of agate bearings, they would each be made in two pieces placed one
at each side of the said steadying plate and be fitted along with it in a box of
suitable shape, but this steadying plate may also be applied to steel bearings. For
instance, it may be readily fitted to steel suspension hooks, by cutting a transverse
slit in the latter in which the steady plate would be fitted.
Or instead of a central steadying plate, as described, the knife-edge may have
lateral steadying spurs formed on it, being upwardly and outwardly inclined.
continuations of said knife-edge, for use with a bearing of ordinary shape.
C. H. BARTLETT,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Patent Agents.
C. H. BARTLETT,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Patent Agents.
COMPLETE SPECIFICATION.
Improvements in Scale-beam Centres and Bearings.
I, CHARLES HENRY BARTLETT of 2 and 3 Welsh Back, Bristol in the
County of Gloucester, Weighing Machine Manufacturer, 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 centres and bearings of scale-beams, and has
particularly for its object to facilitate "lining off" and enable true and perfect
knife-edges to be obtained with the least possible amount of labor.
For this purpose, my invention consists, first, of improved means of fixing the
steel knife-edges in position on the beam and, secondly, of improved means of
centreing or steadying the bearings laterally upon the knife-edges.
The invention will be described with reference to the accompanying drawings

page_text: which illustrate the improvements as applied to one particular form of beam end,
but it is to be distinctly understood that it is in no way limited in this respect but
may be applied to the various other forms in common use such for instance as the
"swan-neck and hook" form, the "Dutch end "beam, and the boxed-in form of
agate bearing; moreover, it is equally applicable to the middle bearing of the
beam, all as will be readily understood without particular illustration of each form
or point of application.
In the drawings,
Figure 1 is a longitudinal section Figure 2 an end view and Figure 3 a plan of
a scale-beam end provided with a knife-edge fixed according to my invention and
an agate bearing provided with my improvements, the same mode of centreing the
bearing on the knife-edge being however equally applicable to a steel bearing.
Figures 4, 5, and 6, are similar views of a modified means of centreing the
bearing.
The same letters of reference indicate the same parts in all the figures.
In scales for commercial use the steel knife-edge centres are usually made of
heart-shaped section and are fixed in the beam by being drifted or driven trans-
versely through the same. When fixed in this way it is difficult to get the centres
perfectly in line and as they are brought to a knife-edge before being driven in
any subsequent adjustment is effected to the detrinient of the straight edge.
According to my invention, the knife-edge is formed on a plate of steel a which
is fixed transversely across a slot in the scale-beam B by its bevelled side edges a¹
being received in corresponding grooves in the side cheeks of the slot, the said
knife-edge plate a being secured firmly in position by a set-screw c screwing into a
part solid with the side cheeks the screw-hole in the plate permitting the
necessary vertical adjustment of the latter. The plate a might, however, simply
fit between the side cheeks without having its edges bevelled and fitted in
grooves.
In order to keep the bearing truly central between, and free from, the side
checks of the slot in which the knife-edge is fixed, a dovetail-shaped central
notch d is made in the knife-edged plate a and a steel steadying plate e is fixed in
the bearing hereafter referred to in a vertical plane at right angles to the plane
of the knife-edge plate a so that the said steadying plate which divides transversely
the V-groove of the bearing will intersect the knife-edge a² and pass and fit
between the two steady points d' formed by the angles of the said knife-edge with
the sides of the dovetailed notch d. Thus the points of contact with the plate e
are in line with the knife-edge a² so that friction is reduced to a minimum. This
is, however, similar in principle to the ordinary mode of centreing when the ends
of the ordinary heart-shaped knife-edges project at opposite sides of the scale-beam
and are bevelled so that the extremities of the knife-edge abut against the cheeks
of the bearing.
In the case of an agate bearing such as represented in Figures 1, 2, 3, it is com-
posed of two pieces of agate g placed one at each side of the steadying plate e and
fitted along with said plate in a box G of suitable shape forming the head of the
scale-pan suspension-hook or mounted on the supporting standard according as the
bearing is at the end or middle of the beam. This steadying plate e may also be
applied to steel bearings of the ordinary V-groove form in which no agate is used.
For instance it may be readily applied to steel suspension hooks by fitting it in a
transverse slit. cut in the head of the hook, the steadying plate projecting across
the V-groove of the bearing and entering a dovetailed notch d in the knife-edge in
the same way as above described.
Instead of a central steadying plate e as above described, the knife-edge plate a
may have lateral steadying spurs h formed on it, as shewn in Figures 4, 5, and 6,
said spurs being upwardly and outwardly inclined knife-edged continuations of the
knife-edge a², a bearing of ordinary shape and having flat sides fitting between
the knife-edges of such spurs at the point where they spring from the knife-
edge a².

page_text: Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :
1. The herein described means of fixing a knife-edged centre to a scale-beam,
which consists in fitting a knife-edged plate transversely between the side cheeks of
a slot in the beam and fixing it by a set-screw to a part solid with the beam, as
described.
2. The herein described means of centreing or steadying the bearing upon the
knife-edge, consisting of a steadying plate fixed across the V-groove of the
bearing fitting between the angles of a dovetailed notch in the knife-edged plate,
as specified.
3. The combination of a knife-edge plate fixed in a slot in the beam
as described and having a dovetailed-shaped notch with a bearing having a
steadying plate fixed in it so as to enter said notch and fit between the knife-edge
angles thereof, as described.
4. The combination, with a knife-edge plate fixed in a slot in the beam as
described, of spurs forming upwardly and outwardly inclined continuations of
the knife edge and of an ordinary bearing fitting between such spurs, as described.
Dated this 1st day of February 1892.
C. H. BARTLETT,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.