up Files and in Apparatus Employed therefor.
Year: 1887

page_text: Date of Application, 24th Aug., 1887
Specification Accepted, 21st Oct., 1887
up Files and in Apparatus Employed therefor.
We RICHARD EGGERT of
Schillerstrasse, Leipsic, Germany and EMIL AUGUST
aus m WEERTH of 4 Schulstrasse, Leipsic, Germany, Manufacturers and Merchants,
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-
22
or
This invention relates to the method of and apparatus for shaping or giving the
requisite curvature to files composed of a series of metal "discs shells built up in
a continuous pile upon a square diamond or other suitably shaped core, and also to the
method of sharpening the edges of the said discs so as to give them the necessary
cutting edge.
In the accompanying drawings Figure 1 represents a complete file composed of a
central core A having a fixed collar A' at one end which forms an abutment against
which the discs or shells A² are forced by means of a loose collar A³ and a nut A*
screwed onto the end of the core A which is threaded for the purpose.
Figure 2 is a part elevation and Figures 3 and 4 are sections illustrating the
method of sharpening and the specially shaped core used in this operation. Figure 5
is a longitudinal section of the sharpening bed or frame and Figure 6 is a cross
section and Figure 7 an end elevation thereof.
Figure 8 is an elevation of the shaping bed with file fixed therein and bent previous
to shaping. Figure 9 shows the position and shape of the file on its release.
Figure 10 is an end view of Figure 9 and Figure 11 a transverse section thereof.
The core A of the file shown in the drawings is rectangular in section and the
discs A2 square, but instead of being flat they are bent diagonally on the line or
axis J J figures 2, 3 and 4, so that when placed on the core the sides or edges of the
disc instead of being at right angles to the centre of the core are oblique thereto as
shown in Figure 2. Although the file shown in the drawings is square it must be
understood that the invention is applicable to any file of angular section.
In manufacturing the files the discs are stamped or cut out in the first instance of
uniform size, and the first process is to reduce them from the centre towards. the ends

page_text: in such manner as to impart a regularly curved and tapered outline to each surface of
the file. To effect this the discs are placed on a temporary core B of wrought iron or
other metal possessing sufficient pliability, the core being straight and of suitable
section, and having collars B' at each end between which the discs are compressed
as shown in Figures 8 and 9. The ends of the core are then placed in recesses c
formed in the ends of the frame C, and the body of the file inserted between the
cheeks D of a clamping block D which fits into a gap or recess in the middle of the
bed in which it is supported by a helical or other spring D2 but can be drawn
downwards by means of a screw wrench D³ which screws as a nut onto the spindle D¹
fixed in the block D.
Whilst the file is lying horizontally above the bed C₁ the screws d are tightened
upon it, bearing plates d' being inserted between the screws and the file to prevent
the latter from being damaged, and then the screw wrench D³ is turned and the
clamp drawn downwards until the underside of the file rests in contact with the
surface of the bed which is concave whilst the upper side of the file likewise
presents a concave surface corresponding with that of the bed. In this position the
upper surface of the file is subjected to the action of a suitable cutting tool, such as
that of a planing machine until the concave surface is reduced to a flat surface, or
until the metal above the dotted linea in Figure 8 shall have been removed, the
metal at the ends being planed off to the level of the central depression. The
clamping screws d are then released and when the discs are strung or threaded upon
their proper core the surface presented by the upper edges of the discs or shells is
convex, the amount of convexity being equal to the amount of curvature previously
imparted to the file or equal to the concavity of the bed C. The form or curvature
of the bed may be varied by means of wedges packing strips or other suitable means,
but as a rule if a change of curvature is required it is preferred to employ another
bed. The necessity for having an altered curve can be met either by the use of a
second bed or by a loose filling plate placed between the first bed and any file that is
placed thereon with a tapered side downwards. Each side of the file is operated on in
the manner thus described, the shape of the bed being altered or the radius of its
curve diminished when it is necessary to place in contact therewith a side of the file
which has been operated on so as to secure the necessary bending of the core to
impart the same curvature to all the faces of the file.
In operating upon a triangular file which cannot readily be clamped by the screws d
it will be found most convenient to use a permanently bent core and to support the
file upon a bed bent to the proper curve and channelled or grooved similarly to the
bed hereinafter described and shown in Figures 5, 6 and 7 so as to support the sides
of the file under the pressure of the cutting tool. If necessary the file might be more
firmly secured to the bed by means of a collar passing over the core about the centre
and having a screwed stem such as D. The permanently curved core can of course
be used when operating on files of any other section and the bed C may be also
shaped in section to correspond with that of the file.
When it is desired to sharpen the file the shells or discs are removed from the
core A and placed in the same order on a coro F (see Figures 2 to 7) which is
rhomboidal in section, the extent of the difference in section between this and the
ordinary core A being readily apparent in Figure 4 from which it will be seen that if
the core be divided horizontally the upper half is flatter than the lower one, thereby
leaving a space between the upper sides of the core and the inner edges of the shells.
In consequence of this space existing the discs are not supported on the core in a
vertical position as in Figure 1 but tilt or lean over as shown at F1 Figure 2, the discs
nearest the end F2 of the figure being shown in their normal position. When tilted
over as at F¹ in Figure 2 the discs present a flat surface but indented where the teeth
have been worn away, as shown at 3 and consequently all that is necessary to sharpen
the edges is to grind up the face or surface presented till these indentations are
removed, and when the discs are returned to their normal position upon the core as
at F2, the cutting edges will be sharp and there will be spaces or serrations between
each disc. The discs are secured in the position shewn at F by means of the specially

page_text: shaped clamping collars G attached to each of which is a link or clamp G¹ through
which pass screws G2. The discs having been placed on the core F and compressed
between the collars G are bound by means of the screws G2 to a bed or trough H
which is straight and supports the core F and the discs against vertical pressure.
As
the discs vary in size the core F has to be curved in order that each disc may bear
properly on the bed H. Thus secured the upper edges of the discs which are inclined
forward are ground or planed until they present a perfectly smooth surface, after
which they are removed from the core and placed thereon in the reverse position, that
is with the unground edges uppermost and the grinding or planing process repeated
on these after which they are replaced in proper order and position on the core A
when the ground faces instead of forming a plane surface will in consequence of the
change of the angle at which they are fixed form a serrated surface as shown in
figures 1 and at F in figure 2.
Having now particularly described and ascertained the nature of our said invention
and in what manner the same is to be performed we declare that what we claim is :-
:-
1. In a file built up of a number of discs of the same size the method of imparting
a convex or curved outline to the faces, consisting in stringing or threading the discs
upon a core curved so as to cause the recession of the discs at or towards the centre of
the length and the protrusion of those at or towards the ends and planing down or
otherwise removing the metal of the protruding discs till a flat surface is obtained
substantially as described and illustrated in the accompanying drawings.
2. The method of imparting a convex or curved outline to the face of a file
consisting in springing or bending the file so as to present a concave surface, and
whilst in this position, planing or otherwise removing the metal at the ends until the
surface becomes flat and afterwards allowing the file to resume its straight or normal
condition substantially as described.
3. An apparatus for bending or curving files consisting of a frame having a curved
bed such as C supporting lugs e and a clamp D for bending the file conformally with
the shape of the bed substantially as described and illustrated in the accompanying
drawings.
4. The method of sharpening files built up of discs such as herein described
consisting in fixing the discs upon a central core at an angle differing from the
normal angle of such discs, and grinding or otherwise dressing the sloping edges
substantially as described and illustrated in the accompanying drawings.
5. An apparatus for holding files during the process of sharpening comprising a
central core such as F upon which the discs A can be tilted, compressing clamps G
and supporting bed or trough H substantially as described and illustrated in the
accompanying drawings.
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