Improvements in Edge-runner Grinding Mills.
Year: 1890

page_text: Date of Application, 2nd June, 1890
Complete Specification Left, 2nd Mar., 1891-Accepted, 4th Apr., 1891
PROVISIONAL SPECIFICATION.
Improvements in Edge-runner Grinding Mills.
I, PERCY JOHN NEATE, of Rochester, in the County of Kent, Consulting and
Mechanical Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention has for its object improvements in the means to be employed in the
more economical working of edge-runner grinding mills and in carrying it into
effect I construct a centre casting in a number of sections but preferably in four,
each composed of two nearly radial wings one tangential bar joining the extremities
of the wings and forming an outer support for a scraper arm, one quarter or other
fraction of hub, a similar fraction of a dust shield for toe step, a lug as near as
practicable to the central shaft to support the inner extremity of one scraper arm,
one large bolt as near the centre shaft as practicable answering the double purpose
of holding the adjoining sections together and forming a pivot for the fixed end
of a runner axle.
I also provide two smaller bolts (one above and one below the axle) near the
extremities of the wings with distance pieces holding the two adjoining nearly radial
wings at such a distance apart that the axle is a fair fit between them. These bolts
together with the tangential bars form a description of closed polygon transmitting
force to the axles at each alternate corner at a considerable distance from the
axle pivots.
The space between the upper and lower distance pieces allows of ample latitude
for the necessary rising and falling of the axle.
I form this axle with a collar upon it and over the collar and axle fits an axle
box carrying an edge runner of any well known or it may be of special
construction.
The axle box is divided transversely at the collar so that the outer half will
transmit inward thrust and the inner half outward thrust to the collar.
I completely close the end of the outer part of the axle bar preferably with a
lubricator and I also close the inner part by means of a detached stuffing box of
ordinary construction. I make however a special connection between the stuffing
box and the inner portion of the axle box as follows.
Across the bottom or outermost part of the stuffing box I cut a slot passing
through its centre line. I also make a similar provision across the innermost face
of the axle box but at right angles to the former slot. I then provide a thin ring
fitting with considerable play concentrically around the axle with two lugs one side
fitting the slots in the stuffing box and two similar lugs on the other side fitting
the slots in the axle box. Each pair of lugs is therefore at right angles to the
other pair and as each pair of lugs is free to slide radially to the axis of the ring
it is clear that by the combined or alternate sliding of one or other pair of lugs the
stuffing box may be easily constrained to rotate about a slightly different centre to
that about which the axle box rotates.
Now if the axle is worn where the axle bar fits it the runner will wobble or run
out of truth and if the stuffing box was rigidly fixed to the axle box it also would
wobble and rapidly destroy the packing.
But owing to the.above described sliding action of the lugs of the ring the stuffing
box will no longer partake of the wobbling or eccentric motion of the runner although
the side faces of the lugs transmit rotary motion to it.
Having attained this result I am enabled to join the stuffing box to the axle box
by means of a flexible oil tight tube of any suitable material and this tube will

page_text: be relieved from all excessive strains by the driving and sliding action of the ring
and a practically perfectly sealed oil chamber will be the result even after the axle
has worn considerably.
Dated this 2nd day of June 1890.
PHILLIPS & LEIGH,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Edge-runner Grinding Mills.
I, PERCY JOHN NEATE, of Rochester, in the County of Kent, Consulting and
Mechanical Engineer, do hereby declare the nature of this invention, and in what
manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
My invention relates to improvements in edge-runner grinding mills, and its
objects are to strengthen the mill, more particularly in the centre, where the axles
join the central vertical shaft, and in respect of the axle arms and boxes.
In order that my invention, and the means by which the same is to be carried into
practical effect, may be thoroughly understood, I will now describe them in detail,
referring in so doing to the accompanying drawings which are to be taken as part
of this Specification and read therewith.
Fig. 1 is a sectional elevation taken on the line A-B of Fig. 2.
Fig. 2 is a plan of the improved means for connecting the axle arms to the central
shaft.
Figs. 3 and 4 are respectively front and side elevations of the junction-ring between
the axle and the stuffing boxes.
Fig. 5 is a front elevation of the scraper-arm socket.
Fig. 6 is a section taken on the line CD of Fig. 5.
A is the vertical central shaft. B, B, B, B are four angle frames or castings.
Each is, in plan, a right angle triangle, and all are counterparts of each other, with
their right angles next the central shaft, where suitable extensions form the hub A'.
Each hypothen use bis, therefore, parallel to a line tangential to the periphery of
the shaft A. The adjacent sides a, a, called wings in the Provisional Specification,
of any two angle frames B, B, are, therefore, parallel. They are held together by
a pair of bolts c, c, and kept apart by two distance pieces d, d. When the four
angle frames and the eight pairs of bolts c and distance pieces are fairly and
properly fixed about the central shaft A, the four hypothenuses b, and the said
bolts and distance pieces will, practically, form a central frame, octagonal in plan,
which is held to the shaft A by the sides a, a, and their extensions which produce
the hub A. I do not confine myself to making this central frame octagon in plan
so long as it is polygonal.
Between each pair of sides or cheeks a, a, an axle arme is pivotted on a boltj
which passes through the said cheeks as close to the shaft A as practicable. Each
bolt is adapted in virtue of its strength and position to discharge the double
function of forming a pivot for the respective axle arm and to assist in holding the
respective two angle frames together. In respect of size and cross section, the axle
arm is a fair fit between the respective pairs of cheeks a, a. It is to be noticed
that the bolts c, c of any one pair are one above the other, the cheeks a, a being
extended upwards and downwards accordingly. The distance between said bolts is
sufficient to allow of the rising and falling of the axle arm which will therefore be
always between its respective checks for the whole length of the latter.
The advantage of the central frame constructed as above described is that the
strains upon it are distributed fairly throughout it. For instance, any one arm e
will put the hypothenuse behind it in compression and the one in front of it through
the bolts c, c, in tension. These strains will be distributed throughout the central
frame, and fracture is rendered practically impossible by there being an operative

page_text: member of such frame adapted in respect of its relative position to suffer and resist
each strain as it is produced during the working of the mill.
It must also be pointed out as a further feature distinctive of my invention and
conducing to its utility, that the power of the central shaft is transmitted to the
axle arms at points considerably outside of their respective pivots and in the
direction of the sources from which come the strains to which the junction of axle-
arms and central shaft are subjected.
9, 9 are sockets projecting upwards from the boss. Their function is to receive
and hold the inner ends of the scraper arms; and h, h are second sockets formed
horizontally through the hypothenuses, and adapted to receive and hold the
outer parts of the scraper arm. is the ordinary dust shield provided to protect
the toe step.
The second part of my invention relates to the axle box, and is illustrated in
Figs. 1, 3, and 4.
is the fore part of the axle arm, of the usual circular cross section, and is a
collar fast thereon. is a front portion and m a back portion which, when bolted
together from opposite sides of the collar k, form the axle box of the edge runner;
the outer portion being adapted to transmit inward, and the inner portion outward,
thrust to the collar. The outer end of the portion is closed by any convenient
device, but preferably by a suitable lubricator. The inner end of the portion m is
closed by a stuffing box n of the usual construction.
The connection between the portion of the axle box, and the stuffing box is of
special construction. A slot o is cut diametrically down the outer face, or bottom,
of the stuffing box at about 20° with the vertical, or thereabouts. A similar slot p
is cut diametrically across the inner face of the axle box, but at right angles with
the former. is a thin metal junction ring embracing the axle arm but fitting it
only loosely. It is furnished with side lugs r, two on each side, those of a pair
being opposite each other and equally interspacing those on the opposite side. The
lugs on one side of the ring play in the slot o and those on the other side in the
slot p. Each pair of lugs is therefore at right angles to the other pair, and as each
pair of lugs is free to slide radially to the axis of the ring, it is clear that by the
combined or alternate sliding of one or other pair of lugs the stuffing box may be
easily constrained to rotate about a slightly different centre to that about which
the axle box rotates.
Now if the axle is worn where the axle box fits it, the runner will wobble or run
out of truth, and if the stuffing box be rigidly fixed to the axle box, it also will
wobble and rapidly destroy the packing. But owing to the above described sliding
action of the lugs of the junction ring, the stuffing box will no longer partake of the
wobbling or eccentric motion of the runner, although the side faces of the lugs
transmit rotary motion to it.
The lugs and slots are illustrated as dovetailed in cross section, but this is a detail
only and may be varied. If they are made as shewn, then will the dovetails-lugs
and slots have the effect of holding the axle box and stuffing box to each other,
but if the lugs and slots are made rectangular in cross section, then some other
device, such as external rigid straps connecting the portion m to the stuffing box
must be adopted.
s is an elastic sleeve embracing the adjacent ends of the stuffing box and axle
box, being adapted thereby to close the inner end of the oil space, to allow for
the sliding motion of the axle and stuffing boxes the one against the other,
and being protected from torsional strain by the slot and lug device above
described.
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 combination of two adjacent angle frames and one bolt adapted in virtue
of its strength and position to discharge the double function of forming a pivot

page_text: for the respective axle arm and to assist in holding the respective two angle frames
together, as set forth.
2. The combination of the hypothenuses of four right angled triangular
frames, pairs of connecting bolts, and distance pieces, the whole forming a central
frame, as set forth.
3. The combination of angle frames arranged around a central shaft, connecting
bolts, and distance pieces, the whole forming a central frame as set forth.
4. The combination in an angle frame of inner and outer scraper arm sockets, as
set forth with reference to the accompanying Figs. 2, 5 and 6.
5. The combination of stuffing box and axle box, as set forth.
6. The combination of stuffing box, axle box, intermediate ring, and lug and slot
devices, as and for the purpose set forth.
7. The combination of stuffing box, axle box, and elastic sleeve, as set forth.
Dated this and dow of Mo 1201
PHILLIPS & LEIGH,
22, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.