Improvements relating to the Mounting of Circular Saws upon their Shafts.
Year: 1893

page_text: COMPLETE SPECIFICATION.
Improvements relating to the Mounting of Circular Saws upon
their Shafts.
I, JOHANN SCHARDT, of Petersplatz 14, Würzburg, in the Empire of Germany,
Cabinet Maker, 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, intended for use on wood working machines, relates to a holder
or clamp for circular saws, which enables the saw-blade to be displaced within
certain limits at any desired inclination to the axis of its shaft, the centre of the
saw-blade remaining always in the axis of the shaft. Owing to the equal and
corresponding lateral inclination of the diameter of the circular-saw resulting from
this fact, grooves of different breadths can be cut out, according as a smaller or
greater inclination is given to the circular-saw.
b
This holder or clamp made of metal or any other suitable material requires a
massive cylinder (see, Fig. 1) which along its length is divided by transverse
sections I, I and II, II' into three portions a b and c (see also Figs. 3, 5 and 6).
The sectional face I I¹ is made obliquely but the sectional face II II' is cut
vertically to the axis III III' of the cylinder. The portions 6 and care intimately
connected together by means of screws f (Figs. 1 and 5) firmly holding the saw-
blade placed between them. For the purpose of accurately fitting the saw-blade
the part 6 has on its face II II' a concentric head e (Fig. 1) of the same thickness
The
as the saw-blade and exactly fitting into the central hole in the saw-blade.
saw-blade is perforated at the places where the screws connect the parts b and c
(see Fig. 5). The parts b and c consequently form one solid whole in which the
saw-blade is fixed. This whole may be called a clamping hub. Upon this hub
loosely rests on the face I I' the portion a called the adjusting block. This
hub and block form together the "cutting-head" which in its axial direction is
bored concentrically with the vertical axis III III and which is put on the
shaft d of the machine (see Fig. 1). The spindle is provided with a thread on
which the nut m with its washer forces the cutter-head against the flange or
enlargement on the shaft. The bore of the adjusting block a corresponds to
the thickness of the shaft d, around which latter, on loosening the nut m, the
said adjusting block can be turned.
The bore of the clamping hub bc on the contrary is turned out spherically the
centre of the sphere being at the point where the axis III, III' traverses
the plane II II in order to receive in the cavity so formed a ball k which
latter is also bored cylindrically in accordance with the thickness of the shaft d.
The ball k and hub be consequently form a ball and socket joint on the shaft d,
constructed in such a manner, that centre of the ball always coincides with the
saw-blade centre.
The saw-blade can consequently be moved into any position on the ball without
shifting its centre from the axis of the shaft d. The ball can be taken out of
the cavity by unscrewing the part c. By turning the adjusting block a around
the spindle d the position of the plane II' is changed and the hub b c is rotated
partially on the ball and socket joint, by which movement the saw-blade is
brought to a greater or less inclination to the axis.
The greatest possible inclination is attained when the adjusting block a has com-
pleted a half revolution (Fig. 2). The maximum of inclination or displacement is
thus definable for each cutter-head, at the beginning being double the angular
inclination of the face I I¹ to the axis III III'.
The ball k has two parallel flattened faces perpendicular to the axis of the

page_text: passage way through it, one of these lies against the flange i, while on the opposite
face a washer g rests, against which the adjusting block a lies, having a cavity with
face vertical to the axis III III' for reception of this washer. This causes the
adjusting block a to press equally in any position upon the washer g and
consequently upon the ball k and forces the latter on turning the nut m against the
flange i of the shaft.
To prevent unintentional displacement of the clamping hub after adjustment,
under the pressure of working during the process of cutting, the hub and block are
provided with means for fixing them together. This is effected by aid of a set-
screw or bolt h (Figs. 1 and 3) which passes through the adjusting block vertically
to the face II', moving in a slit o (Figs. 1 and 3) in said block, and screws into the
clamping hub. By moving this screw or nut thereon the adjusting block and hub
are fixed with regard to each other. As the thickness of material near the slit o,
owing to the oblique position of face I I', would differ at different places, this part
of the adjusting block a is reduced to a uniform thickness by sloping part of its end
face at IV IV parallel to the section face I 11 (see Figs. 1 and 3).
The determination of the inclination of the saw-blade, that is to say, a quick
adjustment for any desired width of deviation from the perpendicular plane is
facilitated by a scale n (Figs. 1 and 4) screwed on the adjusting block a on its edge
near the face I I', while in the latter a pointer p is provided preferably by an
incised nitch as in Fig. 6.
α,
In order that this pointer p may never be covered by the adjusting block the
cylindrical diameter of the hub bc is made a little larger than that of the adjusting
block a.
For the purpose of regulating the scale when rendered necessary by the
gradual wearing out and re-sharpening of the saw-blade, its fixing screws pass
through slits in the scale as shown in Fig. 4.
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 :-
In a device for holding a circular oscillating saw or cutter blade
1. The combination with shaft or spindle d of an adjusting block a adapted to be
revolved on said shaft in a plane perpendicular to the axis thereof and having an
oblique face I, I, a clamping block composed of two parts b and c adapted to
secure the saw-blade between them and having an oblique face corresponding to the
face I, I', a cavity between said parts b and c for reception of a spherical ball k
whose centre lies in the plane of the saw-blade said ball having a passage way for
shaft d, and means for securing the whole in close contact substantially as set
forth.
2. The combination with the parts enumerated in Claim 1 of a scale on part a
and a pointer on part b, with or without means substantially as described for
adjustment of the said scale, for the purpose set forth.
Doted this 11th dor of Tul 1902
R. HADDAN,
Herbert Haddan & Co.,
18, Buckingham Street, Strand, London, Agent for Applicant.