Year: 1896

page_text: Date of Application, 19th Nov., 1888
Complete Specification Left. 19th Aug., 1897-Accepted, 2nd Oct., 1897
We JOHN CRITCHLOW of 25 Shelton Old Road, Stoke on Trent, in the County of
Stafford, Engineer, and TuоыдS SHORE of Grove Place, Shelton, Stoke on Trent, in
the aforesaid County Engineer, do hereby declare the nature of this invention to be
as follows:-
This invention relates to improvements in filter presses and more especially to that
class of press used for filtering, clarifying or purifying "potters slip." The principal
object of the invention is to improve upon the class of filter press illustrated and
described in the Specification of Letters l'atent, No. 17,024 dated the 11th day of
September 1893 and granted to one of the present applicants, and to make the
machine easier to handle and be more efficient in opemtion.
In the machine described in the aforesaid specification the filter trays have each
two arms-one on either side of the tray-and in the underside of these arms are
journalled small rollers which rest upon the surface of the machine framing and
enable the trays to be moved along the latter with little friction. The trays are,
moreover, guided sideways by other rollers or palleys, somewhat similar arrangements
being also adopted with regard to the end plates of the press.
It is an essential feature of our present invention to dispense entirely with these
rollers and to substitute the following arrangement:-Each filter tray has passed
through it, near the centre, a shaft the ends of which project beyond the sides of the
tray. On these ends are fixed pinious which engage with rack teeth formed in the
upper sides of the machine framing or which compose separate racks attachable to
the fmning. The shaft may also project either at one or both ends beyond the
pinion so that there may be placed on it a handle or handles, by turning which the
trays may be forced together. In order to guide the trays sideways the pinions may
be shrouded or provided with flanges which would bear against the sides of the racks,
It will, of course be obvious that instead of the shafts passing through the trays
studs might be attached thereto or projecting axles be formed thereon and the
pinions be mounted loosely upon these. In this case the pinions would each have
a projecting squared boss or similar device to enable them to be turned so as to bring
the trays together as before. They would also be shrouded or flauged as in the
former case.
In the above numbered specification mention is also made of means for forcing
the trays together, these consisting of a screw bearing against one of the end plates
of the press and having at the other end a ratchet or toothed wheel operated by a
ratchet lever to turn the screw round. The screw passes through a nut in the
framing, which is preferably formed in halves.
In the present invention we dispense with this mechanism except the screw which
under the new arrangement merely rests in a hole formed in the framing. On the
screw we place a nut, chased to correspond with the screw, one face of which bears
against the framing. This nut is also formed on its periphery with worm wheel teeth
and gearing with which is a worm that may be operated by means of a shaft and
Handle. When tightening tip the press the screw is first screwed through the nut

page_text: and against the press end, by the aid of a lever or the like and then the screw being
prevented from turning except by the application of greater force is rotated to give
the final squeeze to the press by the worm gear referred to.
The constructional details of the machine may be made of material suitable for
the purpose.
We, JOHN CRITCHLOW of 25 Shelton Old Road Stoke on Trent Staffordshire,
Engineer and THOMAS SHORE of Grove Place Shelton, Stoke on Trent, Staffordshire,
Engineer, 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:-
This invention relates to improvements in filter presses and more especially to that
class of press used for filtering, clarifying, or purifying "potters slip." The principal
object of the invention is to improve upon the class of filter press illustrated and
described in the Specification of Letters Patent No. 17,024, dated the 11th day of
September 1893, granted to one of the present applicants, and to make the machino
easier to handle and be more efficient in operation.
The invention will be fully described with reference to the accompanying drawings
in which
Fig. 1 is a side elevation of a filter press with our improvements applied.
Fig. 2 is a plan of same.
Figs. 3 and 4 end elevations and
Figs. 5, 6 and 7 illustrations of detail parts we shall hereinafter refer to.
In the machine described in the aforesaid specification the filter trays have each
two arms-one on either side of the tray-and in the underside of these arms are
journalled small rollers which rest upon the surface of the machine framing and
enable the trays to be moved along the latter with little friction. The trays are,
moreover, guided sideways by other rollers or pulleys, somewhat similar arrangements
being also adopted with regard to the end plates of the press.
Referring to the accompanying drawings we may say that it is an essential feature
of our present invention to dispense entirely with these rollers and to substitute
therefor the following arrangement :-Ench filter tray A, which so far as its general
character is concerned is constructed as usual, has passed through it, near the centre,
a shaft a, the ends of which project beyond the edges of the tray. On these ends 4
are fixed pinions B which engage with rack teeth C, formed in the upper sides of the
machine framing b or which compose separate racks C, secured to the cross or
supporting rails b¹. We prefer to provide each pinion with a boss c of a sufficiently
large diameter to bear upon the plain part c¹ of the racks and so take the weight of
the filter trays from the teeth of the pinions, this arrangement also enabling the
trays to be moved more freely. Each shaft a is surrounded by a tube or sleeve (1
in which it can rotate and thus prevent any danger of its getting fast by the swelling
of the wood. The shafts may each project at one or both ends beyond the pinions,
and be squared, so that a winch handle D, may be used with them for the purpose of
traversing the trays horizontally and so bringing them in direct contact with each 5
other. The pinions B may be shrouded at one or both ends, if desired, so as to

page_text: engage with the sides of the racks and thus help to guide the movement of the
trays.
Instead of shafta such as a being passed through the trays, stude d might be used
as indicated in Fig. 7, the studs being secured in any convenient way to the trays,
or again projecting axles may be formed on the trays. In both these latter cases the
pinions B would be loosely mounted on the studs or axles and each would have a
projecting squared boss or similar device to enable them to be turned so as to bring
the tmys together as before. The pinions could also be shrouded for the purposes
referred to in connection with Figs. 1 to 5. The number of filter trays used will vary
in accordance with requirements.
In the specification before referred to mention is also made of means for forcing the
trays together, these consisting of a screw bearing against one of the end plates of the
press and having at the other end a ratchet wheel operated by a ratchet lever to turn
the screw round. The screw passes through a nut in the framing. In the present
invention we dispense with the ratchet wheel and lover, whilst retaining the screwed
shaft. In some cases we arrange the screwed shaft E to rest in a hole e formed in
one of the end frames of the press, as shown in Fig. 6. On the screw we place a
nut F, chased internally to correspond with the screw, and one face or side of which
bears against the inner side of the framing. This nut is provided on its periphery
with worm wheel teeth with which gears a worm G that may be operated by means
of a shaft, and winch bandle. In this case when tightening up the trays after they
have been brought together by means of the pinions and racks before described, the
screwed shaft is first rotated and traversed through the nut F and against the end
plate F of the press by the aid of a wheel G1 and handle, lever or the like. When
as much foron as possible has been exerted in this way the remaining requisite
pressure is brought to hear by means of the worm gear referred to. In place, however,
of using this arrangement we have indicated in Figs. 1, 2 and 3 a modified
arrangement in which the screwed shaft E, is passed through the press framing and
also through a nut or screwed bush e (Fig. 2) secured therein. In place of using a
plain wheel (as in the arrangement just described we make this into a spur wheel H
and fix in it a handle h by means of which it can be rotated. This wheel H. is
secured to the screwed shaft so that by turning it the latter can be traversed as
before to force the trays together. In order that extra pressure enn be put on the
trays the wheel H, has gearing with it one or more pinions H¹ mounted on studs hi
secured in the press framing, the said pinious being provided with a boss into holes
in which levers can be placed for rotating the pinions and large wheel H. The
latter may, if desired, for the same purpose be provided with projections A" having
holes in them.
The end plates F and F of the press may also be provided with ears or lugs fin
which bolts, having right or left hand threads, nay be placed for the purpose of
tightening up the corners of the trays. The movable plate F is supported in the
usual way by pulleys g which rest and run on the supporting rails b'.
By the means we have described we claim that the filter press is easier to handle
and is more efficient in operation than the presses hitherto in use.
Having now particularly described and nscertained the nature of our inven-
tion and in what manner the same is to be performed, we declare that what
we claim is :-
1. In filter presses such as those referred to the improved means of supporting and
traversing the filter trays consisting in the use of pinions B fixed on shafts such as a,
or mounted on studs or axles such as d, and engaging with racks such as C or C¹,
substantially as described.
2. The combination with filter trays of filter presses, of shafts a, or studs or
axles d, slooves a³, pinions B, racks C and winch handles D substantially as and for
the purposes described.
3. The improved means of putting pressure upon the filter trays of filter presses
substantially as described,

page_text: 4. The general construction and combination of parts forming our improvements
in filter presses constructed and arranged substantially as described and as shown in
the accompanying drawings.
Dated this 17th day of Aust 1907
WILLIAM H. TAYLOR,
Swan Chambers, 69, Market Street, Mauchester, Agent for the Applicants.