Field of application
[0001] The present invention regards a crushing apparatus for a stone-crushing machine,
according to the preamble of the independent claim 1.
[0002] The present crushing apparatus is intended to be used in a stone-crushing machine,
in particular fixed, together with a plurality of the same apparatuses, on a rotor
roller of the latter, and it is conventionally used for crushing stone material present
in the ground. For such purpose, each crushing apparatus is mounted on the external
surface of the aforesaid rotor roller and supports at least one tooth, susceptible
of penetrating into the ground in order to intercept the stone material present therein
and reduce it into crushed stone or granules of limited size.
[0003] The stone-crushing machine has use in various fields, such as the farm sector for
the reclamation of stony and rocky terrain, the forestry sector for the destruction
of brush or stumps or for the creation and leveling of trails, fire stop trails or
ski trails, as well as the road sector for the definition, leveling or maintenance
of dirt roads, or for the reconstruction of road surfaces.
State of the art
[0004] In the abovementioned reference sectors of the present invention and in particular
in the agriculture/farming sector, stone-crushing machines have for some time been
known that are adapted to advance on a terrain and to crush rock, stones and stone
material generally present in such terrain, for the purpose of rendering the latter
uniform and suitable for being cultivated.
[0005] The stone-crushing machines currently available on the market are of self-moving
type or, more frequently, are intended to be coupled to a drive machine, such as a
tractor, in order to be driven by the latter over terrain that one wishes to treat.
[0006] Conventionally, the stone-crushing machines of towed type comprise a support structure,
of substantially box-shaped form, which is open on the lower part and internally supports
a rotor roller provided, on its peripheral external surface, with a plurality of crushing
apparatuses each of which bearing one or more teeth mounted thereon.
[0007] An interference body susceptible of receiving in abutment the stone material transported
by the teeth is also fixed to the support structure in a position facing the rotor
roller, in order to define a crushing chamber with the latter.
[0008] The rotor roller is rotated around an axis orthogonal to the advancement direction
of the machine by transmission means driven by the power take-off of the tractor.
[0009] Such stone-crushing machines are moved to be displaced by tractor actuation means
between a lifted position, in which the rotor roller is raised from the ground, and
an operating position, in which the rotor roller acts with its teeth on the ground,
intercepting the stones present therein.
[0010] The teeth crush a part of the stone material directly on the ground and another part
of the stone material in the crushing chamber, grinding it against the interference
body and allowing it to then fall on the ground.
[0011] During the operation of the stone-crushing machines, the teeth of the rotor roller
are subjected to very high stresses and, after an expected average lifetime, they
are subjected to damage or breakage. For such reason, teeth are generally movably
mounted in the crushing apparatuses, such that they can be substituted with other
new teeth. Known from the patent
FR 2824759 is an example of a crushing apparatus intended to be fixed to a rotor roller of a
stone-crushing machine together with a plurality of equivalent apparatuses.
[0012] The rotor roller of such known machine is constituted by multiple parallel discs,
fit on a rotation shaft; on each of these, a plurality of peripheral openings are
made. The peripheral openings of each disc are aligned in a direction parallel to
the rotation shaft with the openings of the other remaining discs, in order to form
a plurality of longitudinal seats adapted to house an analogous plurality of crushing
apparatuses. Each crushing apparatus comprises a support bar, which is intended to
be housed in one of the seats of the rotor roller and to be fixed thereto by means
of connection welds to the discs of the rotor roller. Each crushing apparatus also
comprises two tilted teeth, inserted with one engagement portion thereof in a longitudinal
cavity of the support bar and retained thereto by means of locking means so as to
project from the longitudinal cavity with a work portion.
[0013] More in detail, the locking means comprise a wedge adapted to be inserted in the
cavity of the bar in abutment against the engagement portion of the teeth, and two
fixing screws, which traverse two first through holes made in the wedge and two second
through holes, aligned with respect to the first and made on the bottom of the bar,
in order to stop the wedge against the engagement portion of the teeth and consequently
retain the teeth fixed to the support bar.
[0014] The just-described crushing apparatus of known type, nevertheless, has in practice
proven that it does not lack drawbacks.
[0015] The main drawback lies in the fact that the maintenance operations are rather difficult
also for this apparatus of known type, since the nuts that fasten the fixing screws
of the wedge to the bar are hard to access and since, in order to intervene even on
a single worn or damaged tooth, it is necessary to remove the wedge that retains the
teeth.
[0016] For the purpose of remedying the drawbacks of the above-described crushing apparatuses,
crushing apparatuses bearing a single tooth mounted thereon have more recently been
implemented.
[0017] One example of a crushing apparatus of the latter known type is described in the
patent
US 7380576. Such apparatus is intended to be fixed to a rotor roller of a stone-crushing machine
together with a plurality of equivalent apparatuses, each of which comprising a support
body, intended to be fixed to the surface of a rotor roller of a stone-crushing machine,
and a tooth removably couplable to the support body by means of locking means.
[0018] Each tooth is formed by a connection portion, intended to be fixed to the support
body by means of the aforesaid locking means, and a work portion, which is provided
with a metal tip made of particularly hard material.
[0019] More in detail, the work portion and the connection portion of the tooth are arranged
at an angle of about 12° with respect to each other and are connected by a curved
portion. In addition, the connection portion of the tooth is provided with a coupling
seat susceptible of receiving a counter-shaped projecting portion of the support body.
[0020] The abovementioned locking means for fixing the tooth to the support body comprise
two locking screws which are inserted in two corresponding through holes made on the
support body starting from the projecting portion, and through two threaded holes
made on the bottom of the coupling seat and aligned with the through holes of the
support body.
[0021] The latter crushing apparatus briefly described above nevertheless also has several
drawbacks. First of all, such crushing apparatus is structurally complex to make and
consequently has high production costs.
[0022] In addition, the locking means employed in the aforesaid crushing apparatus rigidly
connect the teeth together with the relative support bodies, attaining mechanical
assemblies that are excessively rigid and unsuitable for optimally sustaining the
violent blows and counter-blows that are transmitted between the teeth and the support
bodies during the work operations of the stone-crushing machine.
[0023] For the purpose of speeding up the replacement of worn teeth, known from the patent
US 4240669 is a crushing apparatus intended to be fixed to a rotor roller of a stone-crushing
machine together with a plurality of equivalent apparatuses, each of which comprising
a support body, intended to be fixed to the external surface of a rotor roller of
a stone-crushing machine, and a tooth removably inserted in a bush couplable to the
support body by means of locking means.
[0024] More in detail, the locking means comprise a screw adapted to be inserted in a through
hole frontally made on the support body. Such screw pushes the bush against an opposite
wall of the support body, fixing it and preventing the movements thereof.
[0025] The latter above-described crushing apparatus nevertheless also has several drawbacks.
First of all, such crushing apparatus bases its mechanical strength on the thrust
of a screw, which - being placed frontally with respect to the support body - is intended
to sustain all the shear stresses that are formed during the normal use of the stone-crushing
machine. The stresses thus sustained tend to bend and can even break the screw of
the locking means, requiring a frequent replacement of the crushing apparatus.
[0026] In addition, the maintenance operations are also rather complex for this apparatus
of known type, since the screw of the bar locking means is hard to access, as in order
to unscrew it is necessary to insert a tool between two contiguous teeth, actually
making the replacement rather difficult.
[0027] Also known from the document
US 2009/200855 is a crushing apparatus that provides for interposing several elastic balls between
the stem of the tooth and an internal surface of a seat of the support body. Such
elastic balls engage the stem of the tooth and the seat via friction, in order to
prevent the rotation of the tooth with respect to the support body. The tooth of the
crushing apparatus described in the latter prior art document is nevertheless subjected
to quick wear, since the tooth is intended to hit the ground always on the same point
of its work head.
Presentation of the invention
[0028] In this situation, the problem underlying the present invention is therefore that
of overcoming the drawbacks manifested by the crushing apparatuses of known type,
by providing a crushing apparatus which is structurally simple and inexpensive to
attain and entirely reliable in operation.
[0029] A further object of the present invention is to attain a crushing apparatus which
is mechanically strong in order to endure for prolonged lifetime periods without requiring
periodic maintenance interventions.
[0030] Another object of the present finding is to attain a crushing apparatus which allows
a quick and easy removal and substitution of the damaged or worn teeth with other
new ones.
Brief description of the drawings
[0031] The technical characteristics of the finding, according to the aforesaid objects,
are clearly found in the contents of the below-reported claims and the advantages
thereof will be more evident in the following detailed description, made with reference
to the enclosed drawings, which represent a merely exemplifying and non-limiting embodiment
of the invention, in which:
- figure 1 shows an exploded perspective view of a crushing apparatus, object of the
present invention, in a first embodiment thereof;
- figure 2 shows a sectional side view of the crushing apparatus of fig. 1;
- figure 3 shows a sectional front view of the crushing apparatus of fig. 2 carried
out along the transverse plane III-III;
- figure 4 shows an exploded perspective view of a crushing apparatus, object of the
present invention, in a second embodiment thereof;
- figure 5 shows a sectional side view of the crushing apparatus of fig. 4;
- figure 6 shows a sectional front view of the crushing apparatus of fig. 5 carried
out along the transverse plane VI-VI;
- figure 7 shows a sectional front view of a variant of the aforesaid second embodiment
of the crushing apparatus, object of the present invention.
Detailed description of a preferred embodiment
[0032] With reference to the enclosed drawings, reference number 1 overall indicates a crushing
apparatus, object of the present invention.
[0033] The crushing apparatus 1 is intended to be used on a stone-crushing machine (not
illustrated), in particular fixed to a rotor roller of the latter together with a
plurality of equivalent crushing apparatuses 1. The stone-crushing machine, provided
with a plurality of crushing apparatuses 1 according to the present invention, was
mainly provided for a use in the farming sector for the purpose of crushing the stone
material present in any terrain type and making the latter uniform and suitable for
being cultivated. The same stone-crushing machine can nevertheless be employed for
other purposes, i.e. in sectors different from that of farming, such as the forestry
or road sectors, as long as it is equally intended to reduce stones, rocks, stumps,
branches or materials of different type into fragments of limited size, without departing
from the protective scope of the present patent.
[0034] The crushing apparatus 1, in accordance with the present invention, can in particular
be used in self-moving stone-crushing machines, or machines that are intended to be
coupled to a drive machine, e.g. connected to a three-point attachment of a tractor,
in order to be towed by the latter over terrain that one wishes to treat. The crushing
apparatus 1 is in particular adapted to be employed in stone-crushing machines provided
with a support structure, with substantially box-like shape and open on the lower
part, within which a rotor roller is supported. The latter is provided, on its peripheral
external surface, with a plurality of crushing apparatuses 1, each of which bearing
one or more teeth 2 mounted thereon, in accordance with that illustrated in the enclosed
figures, and it is susceptible of being rotated around an axis orthogonal to the machine
advancement direction by transmission means controlled by the power take-off of the
tractor. Preferably, the apparatus 1 is intended to be used in stone-crushing machines
comprising an interference body, which is susceptible of receiving in abutment the
stone material transported by the teeth and is fixed to the support structure in a
position facing the rotor roller, in order to define a crushing chamber with the latter.
[0035] More in detail, a plurality of crushing apparatuses 1 is fixed on the peripheral
external surface of the rotor roller, advantageously arranged in rows parallel to
the axis of the roller and at regular distances along the circumference of the rotor
roller 100 itself, i.e. distributed according to a geometric design set for carrying
out an improved action on the ground.
[0036] With particular reference to the enclosed figures, in particular in accordance with
figure 1, the crushing apparatus 1 comprises a support base 5 (normally termed "holder-pick
base" in the technical jargon of the field), which is intended to be fixed on the
rotor roller of the stone-crushing machine, e.g. by means of welding, and which is
provided with a housing seat 6.
[0037] The crushing apparatus 1 is provided with at least one tooth 2, which is mainly extended
along a longitudinal axis Z, and is provided with a stem 3 inserted within the housing
seat 6 of the support base 5.
[0038] The tooth 2 comprises a work head 4 for crushing stone material, which is integral
with the stem 3, is extended starting from a first end 7 of the stem 3 and is provided
with a projecting shoulder 8, which is extended transverse to the main extension axis
Z of the tooth 2, preferably with a bulk greater than at least one transverse size
of said housing seat 6 and it is in abutment against a first edge 17 of the housing
seat 6.
[0039] The stem 3 of the tooth 2 is provided with a retention portion 10, which is extended
up to a second end 11 opposite the first end 7 of the stem itself.
[0040] In particular, the tooth 2 is composed of a highly resilient metal material, e.g.
cemented carbide (Widia) and/or steel, or an alloy of multiple metallic materials.
[0041] In particular, the work head 4 and the retention portion 10 of the tooth 2 are extended
starting from two opposite ends of the stem 3. The work head 4 comprises a tip intended
to act against the ground on which the stone-crushing machine advances, in order to
intercept and crush the stone material present therein. The retention portion 10 of
the stem 3, made at its second end 11, is adapted to maintain the tooth 2 constrained
to the support base 5.
[0042] More in detail, the connection stem 3 of the tooth 2 is inserted within the housing
seat 6. In particular, such connection stem 3 has a substantially cylindrical shape,
substantially corresponding to the shape of the housing seat 6.
[0043] In accordance with the first embodiment of the present invention, illustrated in
the enclosed figures 1 - 3, the support base 5 is provided with a support base 24
intended to be fixed to the rotor roller of the stone-crushing machine and with a
bush portion which defines the housing seat 6, in particular by means of a through
hole 9.
[0044] In this situation, the stem 3 of the tooth 2 is placed to traverse the through hole
9 of the bush portion of the housing seat 6, with its retention portion 10 that projects
from the second edge 20 of the housing seat 6, opposite the first edge 17.
[0045] In accordance with a second embodiment of the crushing apparatus 1, object of the
present invention, illustrated in the enclosed figures 4 - 6, the support base 5 comprises
a support base 24 (entirely analogous to the support base 24 of the aforesaid first
embodiment) intended to be fixed to the rotor roller of the stone-crushing machine,
e.g. by means of welding, and a sleeve portion that defines the housing seat 6 for
the stem 3 of the tooth 2.
[0046] In accordance with the second embodiment illustrated in the enclosed figures 4 -
6, the sleeve portion of the support base also comprises an annular abutment wall
25 which is perimetrically defined by an annular shoulder 26 at the first edge 17
of the housing seat 6, in which the projecting shoulder 8 of the tooth 2 is inserted.
[0047] In this manner, the tooth 2 is firmly retained in position during the use of the
stone-crushing machine, decreasing the risk of damaging the tooth 2 itself due to
the mechanical forces that it sustains during the crushing of the stone material.
Advantageously, the projecting shoulder 8 of the tooth 2 is adapted to define an abutment
of the work head against the first edge 17 of the housing seat 6, in order to confer
an abutment to the tooth 2 in its mechanical incision action of the ground during
the crushing operations.
[0048] In accordance with the preferred embodiments illustrated in the enclosed figures,
the work head 4 of the tooth 2 has a substantially conical form, in order to more
easily penetrate into the ground and intercept the stone material present therein,
also at a depth. In addition, the tip is preferably made of hardened metal material
for effectively hitting and crushing the intercepted stone material in the ground
to be worked.
[0049] The crushing apparatus 1, object of the present invention, also comprises locking
means 12 mechanically associated with the retention portion 10 of the stem 3 of the
tooth 2 in order to maintain the latter constrained to the support base 5.
[0050] According to the idea underlying the present invention, the locking means 12 comprise
a first substantially annular groove 13 obtained on the retention portion 10 of the
stem 3 of the tooth 2, a second substantially annular groove 16, facing towards the
first annular groove 13 of the stem 3 of the tooth 2, obtained on the support base
5 outside the housing seat 6 and in proximity to the second edge 20 of the latter,
opposite the first edge 17.
[0051] With the term "annular" used above for identifying the first and the second groove
13, 16, respectively made on the retention portion 10 of the stem 3 of the tooth 2
and on the support base 5, it must be intended generically; hereinbelow in the present
description a groove of substantially curved shape, in particular at least for a section
with annular sector form, must be intended.
[0052] The locking means 12 also comprise a plurality of locking balls 14 inserted in the
first and the second annular groove 13, 16, in order to constrain the stem 3 of the
tooth 2 within the housing seat 6 of the support base 5.
[0053] More in detail, the locking balls 14 of the locking means 12 are arranged substantially
aligned along a ring-like path within the first and second annular grooves 13, 16
and simultaneously interfere with the support base 5 (in particular with the internal
wall defining the hole 9 of the housing seat 6) and with the retention portion 10
of the stem 3 of the tooth 2 and hence mechanically constrain the tooth 2 to the support
base 5.
[0054] In operation, the locking balls 14 of the locking means 12 allow a relative rotation
of the tooth 2 around its main axis Z with respect to the support base 5, such that
with the stone-crushing machine in use, the tooth 2 is free to rotate around such
main axis Z. Indeed, during the normal use of the stone-crushing machine, each tooth
2 is subjected to a plurality of repeated impulsive stresses due to the blows that
it sustains in the impact against the ground; such blows determine, due to the presence
of the locking balls 14, a rotation of the tooth 2 around its main axis Z and consequently
the same tooth 2 comes to be situated in different radial positions following each
blow, which allow a uniform wear of the tooth 2 itself and simultaneously allow the
tooth to absorb part of the impact by means of a rotation thereof.
[0055] Preferably, the housing seat 6 of the support base 5 is tilted with respect to the
peripheral external surface of the rotor roller of the stone-crushing machine on which
it is intended to be fixed.
[0056] The tilt of the housing seat 6 of the support base 5 also tilts the tooth 2 by the
same angle, the stem of such tooth retained in the seat interior.
[0057] In particular, the tilt angle is selected in a manner such that the tooth 2 is introduced
in the ground in a direction substantially orthogonal thereto and can effectively
hit the stone material that it intercepts. In addition, such tilt of the tooth 2 with
respect to the peripheral external surface of the rotor roller allows the tooth 2
to easily drive and lift the non-crushed stone material, until it is introduced in
the crushing chamber of the stone-crushing machine.
[0058] In accordance with the first embodiment of the crushing apparatus, object of the
present invention, illustrated in the enclosed figures 1 - 3, the housing seat 6 of
the support base 5 is provided with a through hole 9 traversed by the stem 3 of the
tooth 2.
[0059] In this situation, the retention portion 10 of the stem 3 of the tooth 2 exits outward
from the housing seat 6.
[0060] In accordance with such first embodiment, the support base 5 comprises a metal ring
15 in which the second annular groove 16 is internally made for the locking balls
14, and such ring is placed around the retention portion 10 of the stem 3 of the tooth
2, in abutment against the second edge 20 of the housing seat 6, in order to lock
the tooth 2 in position.
[0061] More in detail, the metal ring 15 is provided with a through window 22, which connects
the second annular groove 16 with the exterior and therefore is susceptible of being
traversed by the locking balls 14 during the mounting and dismounting of the crushing
apparatus 1, for example for replacing a worn tooth 2.
[0062] In operation, after having positioned the tooth 2 within the hole 9 of the housing
seat 6 with the second annular groove 16 aligned with and facing the first annular
groove 13, the operator inserts the locking balls 14 inside the window 22.
[0063] In this manner, the locking balls 14 are aligned along the first and second annular
grooves 13, 16 along a substantially curved path and in particular a path with annular
sector, with particular reference to that illustrated in the enclosed figures 3 and
6. Otherwise, in accordance with the second embodiment of the crushing apparatus 1,
object of the present invention, illustrated in the enclosed figures 4 - 6, the second
substantially annular groove 16 is integrally obtained in the support base 5 at the
retention portion 10 of the stem 3 of the tooth 2.
[0064] More in detail, in accordance with such second embodiment of the crushing apparatus
1, the sleeve portion of the support base 5 that defines the housing seat 6 for the
tooth 2 is provided with a terminal portion 28 at the second edge 11 of the stem 3
of the tooth 2. Such terminal portion 28 is internally provided with the second annular
groove 16 aligned with and facing the first annular groove 13 made on the retention
portion 10 of the stem 3 of the tooth 2.
[0065] Advantageously, the terminal portion 28 of the support base 5 is provided with a
window 22 placed to connect between the second annular groove 16 and the outside environment,
and is susceptible of being traversed by the locking balls 14 during the mounting
and/or dismounting of the crushing apparatus 1, for example for the substitution of
the worn tooth 2, in a manner entirely analogous to that described above with reference
to the first embodiment of the present invention.
[0066] More generally, the second annular groove 16 is advantageously interrupted by the
window 22, in order to allow the entrance and/or exit of the locking balls 14 during
the mounting and/or dismounting of the apparatus 1.
[0067] In particular, the window 22 interrupts the second annular groove 16 in the sense
that it determines an opening of such second annular groove 16 for the entrance of
the locking balls 14.
[0068] Advantageously, the stem 3 of the tooth 2 is provided, on its lateral surface, with
a third substantially annular groove 18 in which an elastic element 19 is housed which
is adapted to interact with friction against the internal surface of the housing seat
6, in order to limit the movements of the tooth 2 along the main axis Z.
[0069] In particular, in accordance with the preferred embodiments illustrated in the enclosed
figures, the elastic element 19 is an elastic open washer housed in the third annular
groove 18 of the stem 3 of the tooth 2.
[0070] In this manner, the elastic element 19 remains in position, being housed in the third
annular groove 18 and it acts elastically in expansion against the internal wall that
defines the hole 9 of the housing seat 6 of the support base 5.
[0071] Such elastic force imparted by the elastic element 19 brakes the tooth 2 with respect
to the housing seat, decreasing the movements of the tooth 2 itself along the main
axis Z during the use of the stone-crushing machine, consequently limiting the wear
of the entire the crushing apparatus, which otherwise would be subjected to repeated
stresses of overly high intensity.
[0072] The locking means 12 comprise a stop element 21 mechanically constrained to the support
base 5 and at least partially placed to interfere with the locking balls 14 placed
within the second annular groove 16, in order to stop the locking balls 14 in position.
Preferably, the stop element 21 engages the second annular groove 16 at the aforesaid
window 22.
[0073] In accordance with the first embodiment, the metal ring 15 is provided, on the external
cylindrical surface, with a fourth annular groove 29 interrupted by the window 22
which communicates with the second annular groove 16.
[0074] In such fourth annular groove 29, the stop element is housed which, in accordance
with the first embodiment illustrated in the enclosed figures 1 - 3, is an open metal
ring provided with one end thereof bent and inserted inside the window 22, to obstruct
the latter so as to prevent the exit of the locking balls 14 from the first and second
annular grooves 13, 16.
[0075] In accordance with the second embodiment illustrated in the enclosed figures 4 -
6, the support base 5 is provided with two shoulders 23 arranged to the side of the
window 22 and each provided with a through hole 27, which are aligned with each other.
Advantageously, in accordance with such second embodiment, the stop element 21 is
a pin or a split pin.
[0076] More in detail, the pin (or the split pin) is inserted within the through holes 27
of the shoulders 23 and is placed to obstruct the window 22, in order to prevent the
exit of the locking balls 14.
[0077] Figure 7 illustrates an example of a variant of the aforesaid second embodiment illustrated
in figures 4-6.
[0078] In particular, in such variant of figure 7, the stop element 21 of the locking means
12 comprises a bolt.
[0079] More in detail, the bolt of the stop element 21 comprises a screw inserted within
the through holes 27 of the shoulders 23 and placed to obstruct the window 22. In
addition, the bolt of the stop element 21 advantageously comprises a nut engaged via
screwing the stem of the screw at an end thereof opposite the head of the screw itself,
in order to lock the latter in position.
[0080] In operation, the operator, for the purpose of mounting or dismounting the crushing
apparatus, object of the invention, must first remove the stop element 21 placed to
obstruct the window 22 so to be able to remove the locking balls 14 from the first
and second annular grooves 13, 16 which engage both the tooth 2 and the support base
5. Once the locking balls 14 are removed, the tooth 2 is released from the support
base 5 and the technician can extract it in order to substitute it with a new one.
[0081] The finding thus conceived therefore attains the pre-established objects.
1. Crushing apparatus (1) for a stone-crushing machine, intended to be fixed to a rotor
roller of a stone-crushing machine together with a plurality of equivalent crushing
apparatuses (1), and such crushing apparatus comprises:
- a support base (5) intended to be fixed on the rotor roller of said stone-crushing
machine and provided with a housing seat (6);
- at least one tooth (2), which is mainly extended along a longitudinal axis (Z),
and is provided with:
- a stem (3) inserted within said housing seat (6) of said support base (5);
- a work head (4) for crushing stone material, which is integral with said stem (3),
is extended starting from a first end (7) of said stem (3) and is provided with a
projecting shoulder (8), which is extended transverse to the longitudinal axis (Z)
of said tooth (2) in abutment against a first edge (17) of said housing seat (6);
- said stem (3) being provided with a retention portion (10), which is extended up
to a second end (11) opposite said first end (7);
- locking means (12) mechanically associated with the retention portion (10) of the
stem (3) of said tooth (2) in order to maintain said tooth (2) constrained to said
support base (5);
wherein said locking means (12) comprise:
- a first substantially annular groove (13) obtained on the retention portion (10)
of the stem (3) of said tooth (2);
- a second substantially annular groove (16), facing towards the first annular groove
(13) of the stem (3) of said tooth (2), obtained on said support base (5) in proximity
to a second edge (20) of said housing seat (6), opposite the first edge (17);
- a plurality of locking balls (14) inserted in said first and second annular grooves
(13, 16), in order to constrain the stem (3) of said tooth (2) within the housing
seat (6) of said support base (5);
said crushing apparatus (1) being
characterized in that said locking means (12) also comprise a stop element (21) mechanically constrained
to said support base (5) and at least partially placed to interfere with said locking
balls (14) within said second annular groove (16) in order to stop said locking balls
(14) in position.
2. Crushing apparatus (1) according to claim 1, characterized in that said support base (5) comprises a metal ring (15) in which the second annular groove
(16) is internally made for said locking balls (14), and such metal ring is arranged
in abutment against the second edge (20) of said housing seat (6), in order to lock
said tooth (2) in position.
3. Crushing apparatus (1) according to claim 1, characterized in that said second substantially annular groove (16) is integrally obtained in the support
base (5) at said retention portion (10) of the stem (3) of said tooth (2).
4. Crushing apparatus (1) according to any one of the preceding claims, characterized in that said second annular groove (16) is interrupted by a window (22) engaged by said stop
element (21).
5. Crushing apparatus (1) according to any one of the preceding claims, characterized in that the stem (3) of said tooth (2) is provided, on its lateral surface, with a third
annular groove (18) in which an elastic element (19) is housed that is adapted to
interact with friction against the internal surface of said housing seat (6) in order
to limit the movements of said tooth (2).
6. Crushing apparatus (1) according to claim 5, characterized in that said elastic element (19) is an elastic open washer housed in said third annular
groove (18) of the stem (3) of said tooth (2).
7. Crushing apparatus (1) according to any one of the preceding claims, characterized in that said stop element (21) is a pin or a split pin.
8. Crushing apparatus (1) according to claims 4 and 7, characterized in that said support base (5) is provided with two shoulders (23) arranged to the side of
the window (22) and each provided with a through hole (27) traversed by the pin of
said stop element (21) in order to stop said locking balls (14).