Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1 E`IELD OF THE INVENTION
The invention relates to circular saw blades with exchangeable
work performing elements, especially for use in industrial
type stone and rock saws.
BACKGROUND INFORMATION
Canadian Serial No.~ , filed in the Canadian Patent
Office on February 16, 1990, by the inventors: Manfred Fuerst
and Erwin Schumacher, and entitled: Circular Saw Blade, discloses
a circular saw blade having a blade body made as a laminated
structure of fiber reinforced synthetic materials. The individual
layers are made up of sec-tors that abut each other in the same
layer. Neighboring layers are angularly displaced relatlve to
each other so that the butt joints are overlapped by at least
one neighboring layer sector. By angularly displacing the abut-
ting joints relative to one another from layer-to-layer an im-
proved strength is achieved. Compared to a circular saw blade
having a blade body made of steel, the fiber reinforced blades
are generating less noise while having the same material strength
and stiffness. Additionally, the construction of several fiber
reinforced layers for the blade body is possible with relatively
small manufacturing expenses so that the structural investment
for making such fiber reinforced circular saw blade can be main-
tained low. However, with regard to the requirement tha-t work
performing elements must be easily exchangeable, the problem
arises that a releasable connection must be provided between
the work performing elements and the attachment pieces which
are secured to the circumference of the blade body. This
releasable connection must assure the desired exchangeability
-- 2
1 releasable connection must assure the desired exchanyeability
of the work performing elements on the one hand, while on
the other hand it must guaranty the required connection
safety so that the work per.~orming elements cannot break
out of the saw blade during operation. For this purpose
it is necessary that the connecting means assure a maximum
of force transmission between the work performing elements
and the saw blade body, and this must be accomplished in
a relatively narrow available space which is limited by
the thickness of the blade body.
OBJECTS OF THE INVENTION
In view of the foregoing it is the aim of the invention
to achieve the following objects singly or in combinatlon:
to construct a saw blade, especially a rock or
stone circular saw blade so that it satisfies the above
mentioned requirements in an optimal way, yet with a small
structural efEort and expense;
to connect the work perEorrning elements, such
as cuttlng or grinding elements, to the body oE the saw
blade with a threaded connection so that these work perform-
ing elements can be easily and ind:ividually replaced; and
to provide a connection of the work performing
elements to a saw blade body which is equally applicable
to metal saw blade bodies and to synthetic material layered
saw blade bodies.
i3
1 SUM~RY OF THE INVENTION
A circular saw blade according to the invention is character-
ized in that the individual cutting or grinding element is
connected with its corresponding attachmentpiece by a mount-
ing fork having two legs riding in an overlapping manner on
the respective attachment piece. A threaded connection is
provided between the mounting fork and the attachment piece.
For this purpose through-holes aligned with each other pass
through the legs of the mounting fork and through the attach-
ment piece. A bushing with an internal threading passesthrough the aligned holes and a threaded bolt passes into
the threaded bushing so that the bushing bears with its
flange or flat head against one side of a mounting leg while
the threaded bolt bears with its flat head against the other
side of the respective leg of the mounting fork.
The invention recognizes that the required forces can be
taken up effectively by the overlap of the fork legs on
both sides of the attachment piece in combination with the
threaded connection which assures for each individual work
performing element a desired screw-on pressure between the
respective attachment piece and the corresponding mounting
fork. The screw-on pressure is introduced approximately
into the entire mounting width that is determined by the
thickness of the blade body. Such pressure distribution
makes it possible for the connection to take up the required
forces which can be quite large in this type of saw blade.
s~
1 Preferably, each work perEorming element has its own
mounting fork.
An improved pressureor force transmission is obtained by
a location fit between the inwardly facing surfaces of the
legs of the mounting fork and the outwardly facing surface
of the respective attachment piece. The gap width between
the legs of the mounting fork is dimensioned with due regard
to the thickness of the attachment piece to assure such
location fit. Similarly, a loca-tion fit should be provided
between the bushing and the through-holes in the legs of the
mounting fork and the attachment piece. By locating the
flat head or flange of the th r e a de d bushing and the flat
head of the screw bolt entirely in a respective recess, the
surfaces of the connection remains aerodynamically satis-
factory without increasing the saw blade noise during
operation. Even the recessed screw head and recessed bushing
flange can easily be loosened or tightened by a tool by
providing respective tool pins.
BRIEF DESCRIPTION OF THE DRAWING
In order that the invention may be clearly understood, it
will now be described, by way of example, with reference
to the accompanying drawing in whi.ch the single figure is
a view partially in section, through a connecting structure
according to the invention, whereby the sectional plane
extends radially through the saw blade.
1 DETAILED DESCRIPTION OF A PREFERRED EXAMPLE EMBODIMENT AND
OF THE BEST ~ODE OF T~E INVENTION
The sectional view of the single figure shows a blade body 1
with individual layers 1.1 and 1.2. An attachment piece 2
is secured to the blade body 1 in the manner described in
more detail in the above mentioned copending application
Canadian Serial No.~ . The layers 1.1 and 1.2
are, for example, made of fiber reinforced synthetic materials
in which the attachment element 2 of metal is embecdded. A
work performing element 5, such as a cutting tip or a grind-
ing element, is secured to the blade body 1 in accordance
with the invention by means of a mounting fork 6. The ele-
ment 5, for example, of diamond or some other material suit-
able for stone working, is secured to the mounting fork 6
in a conventional manner, for example, by a suitable aclhesive.
The mounting fork 6 has a through-hole 6.3 in its upper
portion for the insertion of a tool for removing the mount--
ing fork 6 from the attachment piece 2. Further, -the mount-
ing fork 6 has two legs 6.2 and 6.2'. The mounting fork 6
rides on the attachment piece 2 so that the legs 6.2 ancl 6.2'
overlap both sides o:E the attachment piece 2. The mounting
fork has a through-hole 6.1 in each of its legs 6.2, 6.2'.
The attachment piece 2 also has a throuyh-hole 2.2 which
is registering with the two through-holes 6.1 in the legs
of the mount.illg fork. The mounting :Eork 6 is rigidly secured
to the attachment piece 2 by a bushing 7 cooperating with
a threaded bolt 8. The bushing 7 has a bushing section 7.2
1 and a flange type flat head 7.1. The bushing section 7.2
has a threaded through-hole 7.4. The screw bol-t 8 has an
external threading engaging the internal threading 7.4.
The screw bolt 8 also has a flat head 8.1. The leg 6.2 has
a recess 6.4 in which the flat head 8.1 is received. The
leg 6.2' has a recess 6.5 in which the flange type flat
head 7.1 is received.
The spacing between the legs 6.2 and 6.2' is so dimensioned
relative to the width or thickness of the attachment piece 2
that the mounting fork 6 rides with a location fit on the
attachment piece 2. This feature makes sure that a force
transmission friction fit is provided when the screw bolt 8
is tightened in the threaded bushing 7. As a result, the
connection of the mounting fork 6 with the attachment piece 2
can take up even loads that are effective in the axial direc-
tion of the screw connection formed by -the screw bolt 8
and the threaded bushing 7, in addition to radial loads.
A further location fit is provided between the bushing sec-
tion 7.2 and the holes 6.1 and 2.2. ~'or this purpose the
outer diameter of -the bushing section 7.2 is dimensioned
with due regard to the diameter of the holes 6.1 and 2.2.
The bushing section 7.2 has such an axial length that it
leaves a ring space 7.5 between the axially inwardly facing
end of the bushing section 7.2 and -the inwardly facing sur-
face of the head 8.1 of the screw bolt 8. Thus, tightening
``" 2@~ 63
1 of the connection is assured. Simultaneously, the length
of the bushing section 7.~ is such that it is subjected
to a shearing load in two planes. In other words, the
axially inner end of the bushing section 7.2 .reaches far
enough into the holes so that the wall of the right-hand
hole 6.1 bears against the circumference of the axially
inner end of the bushing section 7.2. As mentioned, it
is preferable that a location fit is provided between all
the three holes on the one hand, and the outer surface of
the bushing section 7.2.
The flange 7.1 of the bushing 7 is provided with two or
more holes 7O3 for the insertion of a tool. Similarly,
the flat head 8.1 of the screw bolt 8 is provided with two
or more holes 8.2 for the insertion of a tool. Thus, the
tightening or loosening of the threaded connection is assured.
Incidentally, the construction is such that the mlrror~sym-
metrical arrangement permits the insertion of the sleeve
from either side. Similarly, the flat head screw bolt 8
can be lnserted from either side.
Although the invention has been described wlth reference
to specific example embodiments, it will be appreciated
that it is intended to cover all modifications and equiva-
lents within the scope of the appended claims.
