Improvements in Machines for Grinding and Sharpening Shearing Combs and Cutters and certain other Tools and Instruments.
Year: 1891

page_text: Date of Application, 30th Nov., 1891-Accepted, 5th Mar., 1892
COMPLETE SPECIFICATION.
Improvements in Machines for Grinding and Sharpening Shearing
Combs and Cutters and certain other Tools and Instruments.
We, JOHN MOFFAT, of Irvinebank, Queensland, and Bridge Street, Sydney,
New South Wales, Tin-smelter, and WILLIAM WRIGHT VIRTUE, of Bridge
Street, Sydney, 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 machines for grinding and sharpening
shearing combs and cutters, and such other tools and instruments as can be ground
and sharpened upon a rotating plate armed with an abrading face of emery or like
material.
In carrying out the invention means are provided for stretching a sheet of emery
cloth upon a disc and securing it thereon.
The main features of the invention are: 1st-stretching and securing the emery
cloth in a single action by special means; 2nd-securing the emery sheet, and
when it is secured stretching it over the disc by an independent action.
The invention also embraces a construction whereon the sheet is griped and
stretched over a back plate to which it is secured by gluing.
Referring to the annexed sheet of explanatory drawings,
Figure 1 is a longitudinal section through a double grinding machine,
Figure 2 a transverse section through one of the brackets,
Figure 3 top plan of the frame,
Figure 4 detail section enlarged showing an arrangement of griping ring.
The two main modifications of the invention are illustrated in Figure 1, the first
on the left and the second on the right of that figure.
Referring to Figure 1,-1 is the frame, 2 brackets, 3 plummer blocks, 4 brasses,
5 fast pulley, 6 loose pulley, 7 bush, 8 main spindle, 9 belt gear, 10 screwed end of
spindle, 11 reduced screwed end of spindle, 12 travelling nut, 13 collar thercon,
14 back plate, 15 hollow hub thereof tapped, 16 collar on hub 15, 17 collar ring
screwed into the hub 15 and turned internally, 18 key or spline, 19 jaws of back
plate, 20 face disc, 21 rounded edges of same, 22 hub or boss screwed into the part 11
and turned externally so as to slide within the collar ring 17. The spline 18
prevents the back plate turning relatively to the disc.
In fitting a grinding cloth in the construction shewn in the left of the figure, the
nut 12 is run out on the screw 10, whereby the back plate is made to advance
until its jaws clearly overhang the surface of the face plate. The sheet of cloth is
then spread on the face plate with the edges under the jaws of the back plate, and
the nut 12 run back on the screw 10 slowly. As the jaws 19 retreat towards the
rim of the face plate, the edges of the emery sheet become pinched between these
parts, and as the motion is continued the sheet is drawn taut upon the face plate
and held firmly thereon. The nut. 12 is operated with a spanner, but if desired a
hand wheel or lever may be secured to it for the purpose.
In the alternative arrangement shewn in the right of the figure the principle is
different. The construction and combination of the parts marked 10, 11, 12, 13,
15, 16, 17, 18, 20, 21 and 23 is, however, similar; 23 are pinching screws, three or
more in number, passing through holes in the back plate and making contact with
the back of the face plate. These screws serve the purpose of putting extra tension
on the cloth when necessary and truing the plate and preventing rotary motion of
the disc and back plate relatively to one another; and it may be used, if desired, with
the construction previously described. 24 is the griping ring, and 25 screws securing
the same to the back plate. The emery sheet is set by running out the nut 12 until

page_text: the back plate overhangs the surface of the face plate, inserting the edges of the
cloth under the griping ring and securing the same therein by means of the said
screws 25, and then running back the nut 12, thereby drawing the back plate
rearwards relatively to the face plate and stretching the cloth upon the latter.
In another modification, the emery cloth, freshly glued on the back, is griped upon
the back plate and then drawn back against the face plate as before described, whereby
it is stretched and spread uniformly thereon; when dry and set the tension" may
be relieved if desired. It will be evident that this principle of construction may
be adapted for use with machines of known constructions, wherein a sheet of emery
cloth is glued to a face plate; in such case the griping frame and the mechanism
for advancing and retiring it relatively to the face plate is made as an attachment,
of which many forms may be devised by a skilful mechanic. Such an attachment
might consist of two rings of the necessary stoutness and of a greater diameter
than the face plate or disc, provided with screws or dogs or like devices arranged
to take against the back of the disc, over which they are made to swing. In
operation, the edges of the cloth are griped between these rings, and the dogs are
then screwed up so as to draw the rings rearward from the disc and stretch the
cloth (the back of which has been previously served with glue), over the disc.
The face plates are always made slightly higher towards the centre than at the
edges, in order to ensure perfect contact of the cloth therewith at all points; but
in this there is no novelty.
The back plate need not be solid; it may be formed with spokes, if desired.
We do not restrict ourselves to the use of emery cloth, as other textile substances
or fabrics provided with abrading faces of emery or of other materials of a like
nature, may be used in lieu thereof. And we would have it understood that the
main essence of our invention is not confined to the mechanical details described
and illustrated, but includes the several constructions and combinations hereinafter
claimed.
We are aware that grinding and sharpening machines and sand-papering machines
are known in which a sheet of emery cloth or paper, or glass cloth or paper has
been glued or cemented to a face plate; and in which such a sheet has been secured
against the face by means of a ring driven about or screwed upon the periphery of
the face plate.
Having now particularly described and explained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is:-
1.-A. grinding and sharpening machine consisting of a face plate or disc, a sheet
of emery cloth or other abrading fabric spread thereon, a ring for pinching the
edges of such cloth against the rim of the face plate, and means or mechanism,
substantially as described, for advancing and for retiring the ring relatively to the
face plate.
2. In a grinding and sharpening machine of the class described, the combination
of a face plate or disc, a sheet of emery cloth or other abrading fabric spread
thereon, a back plate having a claw ring such as 19 at its periphery, and means or
mechanism, substantially as described, for advancing and for retiring the back
plate relatively to the face plate.
3. The combination, substantially as described, of the parts marked 10, 11, 12,
13, 14, 15, 16, 19 and 20 in the drawings.
4. The combination, substantially as described, of the parts marked 14, 19
and 20 in the drawings.
5. A grinding and sharpening machine consisting of a face plate or disc, a back
plate movable relatively to the face plate, and means or mechanism for securing a
sheet of emery cloth or other abrading fabric to the back plate, substantially as
described.
6. In a grinding and sharpening machine of the class described, the combination
of means or mechanism for holding a sheet of emery cloth or other abrading fabric

page_text: about the edges, and a plate or disc independent of such means or mechanism and
movable relatively thereto, or relatively to which the said means or mechanism is
movable, and over which disc or plate the said cloth or fabric is stretched and held
substantially in the manner described.
7. The combination of the parts marked 14 and 20 in the drawings, means or
mechanism for advancing and for retiring these parts relatively to one another, and
means or mechanism for securing a sheet of emery cloth or other abrading fabric to
the part 14.
8.-The combination, substantially as described, of the parts marked 10, 11, 12,
13, 14, 15, 16 and 20 in the drawings, and means or mechanism for securing a sheet
of emery cloth or other abrading fabric to the periphery of the part 14.
9. The combination of a face plate or disc, a sheet of emery cloth or like
abrading fabric, a ring or frame for griping such cloth or fabric about the edges,
means or mechanism for retiring the ring or frame relatively to the face plate or
disc, and a glue or equivalent film between the cloth and the disc.
10. An abrading cloth or fabric setting and stretching attachment for grinding
and sharpening machines of the kind described, consisting of a ring or frame for
griping the cloth about the edges, and means or mechanism for retiring such ring
or frame relatively to the face plate or disc.
Dated this 30th day of November 1891.
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.Č., Agent for the Applicants.