DESCRIPTION

Technical field

The subject of the present invention is a crusher bucket for crushing stone and/or similar materials, of the type described in the preamble to the main claim.

Background art

Self-propelled vehicles equipped with crusher buckets for collecting material such as stone or the like, inside which crushing means are provided for crushing the material collected to the desired size are known in the technical field referred to.

An example of known crusher buckets comprises a scoop-like body and two jaws, of which one is fixed relative to the scoop-like body and the other can oscillate relative thereto, and which are moved so as to compress the material admitted to the bucket between them and hence to crush the material.

These crusher buckets comprise means for adjusting the crushing dimension which use counterthrust struts having a first end which can slide in an upper seat formed in the body of the crusher bucket and a second end which can slide in a lower seat formed in a jaw that is movable relative to the body of the crusher bucket. The crushing dimension is typically adjusted by means of a plurality of spacers which are located in the upper seat, between the base of the seat and the first end of the strut. The spacers are removed or added in order to increase or decrease, respectively, the crushing dimension, that is the output size of the material crushed by the crusher bucket.

The assembly constituted by the spacers, by the counterthrust strut, and by the movable jaw of the crusher bucket is clamped as a pack by means of a tie which is fixed firmly to the movable jaw and is acted on by a spring which bears on a reaction element fixed firmly to the crusher bucket body. A first problem which arises in buckets produced in this manner is that of the adjustment of the spring that is used in the above-described assembly. In fact, after the insertion or removal of the adjustment spacers, the spring may not be compressed in an optimal manner, thus giving rise to anomalous vibrations which may adversely affect the bucket, in particular, the counterthrust strut and the crusher bucket body.

A second problem which may occur is alteration of the mechanical characteristics of the spring over time. In fact, the elasticity characteristics of the spring may change over time because of wear, leading to dangerous vibrations.

A third problem which arises is the ability of the spring to withstand low temperatures, in particular temperatures below zero degrees centigrade. In these situations, the spring becomes more fragile and may reach breaking point, with considerable damage to adjacent members.

In particular, in all of the above-described situations, the anomalous vibrations caused by the spring in the bucket structure may also cause the counterthrust strut to come out of its seat.

Description of the invention

The objective of the present invention is to make available a crusher bucket such as to overcome the problems discussed with reference to the prior art mentioned, by providing a bucket comprising means for adjusting the crushing dimension, the efficiency of which is constant and independent of manual interventions by the operator, of wear of the mechanical components of the bucket, and of the temperature of use, without prejudicing any of the functional characteristics of the bucket, in particular the movement of the movable jaw.

This and other objectives which will become clear from the following description are achieved by the invention by means of a crusher bucket according to the appended claims.

Brief description of the drawings

The characteristics and the advantages of the invention will become clearer from the detailed description of a preferred embodiment thereof which is described purely by way of non-limiting example with reference to the appended drawings, in which :

Figure 1 is a sectioned side view of a crusher bucket according to the present invention,

Figure 2 is a view of the detail II of Figure 1, on an enlarged scale,

Figure 3 is a view of the crusher bucket of Figure 1, from above,

Figure 4 is an axonometric view of the crusher bucket of Figure 1,

Figure 5 is a view of the detail V of Figure 4, on an enlarged scale,

Figure 6 is a side view of the crusher bucket of Figure 1,

Figure 7 is a section taken on the line VII-VII of Figure 6,

Figure 8 is a view corresponding to that of Figure 1 of a variant of the crusher bucket according to the present invention,

Figure 9 is a view of the detail IX of Figure 8, on an enlarged scale, Figures 10a, 10b are two axonometric views of the view of Figure 9 and of a variant thereof, respectively,

Figure 11 is a view of a detail of Figure 9, on a further enlarged scale, Figure 12 is a view corresponding to that of Figure 1 of a further variant of the crusher bucket according to the present invention, and

Figure 13 is a view of the detail XIII of Figure 12, on an enlarged scale. Preferred embodiment of the invention

A bucket formed in accordance with the present invention is generally indicated 1 in the drawings.

The bucket 1 is arranged to be connected, in known manner, for example by means of mountings 3, to the free end of one or more arms of a self- propelled vehicle (not shown).

The bucket 1 comprises a scoop-like body 2 provided with an inlet opening 4 for the loading of stone, pebbles, rocks and inert materials in general to be crushed, the inlet opening 4 having an enlarged cross-section in comparison with an opposed outlet aperture 5 for the discharge of the crushed material.

Stone crushing means are mounted in the scoop-like body 2 and comprise a movable crushing jaw 6 and an opposed fixed crushing jaw 7 fixed firmly to the body 2. Each of the movable and fixed jaws 6, 7 includes a respective frame 6a, 7a to which is releasably fixed a respective plate 6b, 7b provided with longitudinal grooving, indicated 10, extending parallel to the direction of flow of the stone admitted, for facilitating the crushing thereof. The grooving 10 defines a plurality of ribs 10a and recesses 10b in alternating sequence such that a recess 10b of the fixed jaw 7 corresponds to a rib 10a of the movable jaw 6 so that, during the movement of the first jaw 6, the crushing of the material is homogeneous. Moreover, since the ribs 10a of one jaw can penetrate into the recesses 10b of the other jaw, the crushing can be particularly fine.

The jaws 6 and 7 define inside the bucket 1 a crushing zone which is delimited laterally by opposed sides 11 of the scoop-like body 2.

The bucket 1 comprises means for moving the movable jaw 6, including drive means, for example, a hydraulic motor (not shown) which is housed inside the scoop-like body 2 and by means of which a drive shaft 14 is driven.

An eccentric mechanism 15 is provided on the shaft 14 for transmitting to the movable jaw 6 an oscillatory motion relative to the fixed jaw 7.

The bucket 1 further comprises means 22 for adjusting the distance between the first and second jaws in the region of the outlet aperture 5. The adjustment means 22 comprises a strut 23 having two ends 23a, 23b which can slide in respective seats 24, 25 one formed in the scoop-like body 2 and the other in the frame 6a of the movable jaw 6. A plurality of spacers 26 can be interposed as a pack between the base of the seat 24 and the end 23a of the strut 23. The number of spacers 26 can be varied in order to adjust the width of the outlet aperture 5.

The bucket 1 comprises an adjustable tie 30 for clamping the strut 23 and the spacers 26 as a pack with a preset compression preloading. The adjustable tie 30 as a whole is non-resilient.

In the embodiment of Figures 1 to 7, the adjustable tie 30 is a hydraulic jack 30a acting between the scoop-like body 2 and the second, movable jaw The hydraulic jack 30a comprises a cylinder 31 fixed firmly to the scoop-like body 2 and a piston 32 slidable in the cylinder 31. The cylinder 31 is fixed to the scoop-like body 2 by means of a plate 33 which is arranged in a manner such that the piston 32 can slide along an axis almost parallel to the seat 24 of the strut 23.

The piston 32 can slide in the cylinder 31 away from and towards a base

31a of the cylinder 31, along an internal wall 31b thereof.

A rod 34, which is associated with the piston 32 and fixed firmly thereto, extends out of the cylinder 31 and has a free end 35 which is remote from the piston 32 and is articulated to a connecting rod 36 connected to the movable jaw 6. A chamber 37 is defined between the internal wall 31b of the cylinder 31 and the rod 34; oil can be delivered to or withdrawn from the chamber in order to move the piston 32 and the rod 34.

The connecting rod 36 has two ends 36a, 36b which are articulated, respectively, to two pins 38, 39 which are fixed to the rod 34 at the free end 35, and to the movable jaw 6, respectively.

According to a variant of the invention (not shown), the actuator comprises a cylinder articulated to the scoop-like body 2 and a piston which can slide in the cylinder and with which is associated a rod that extends out of the cylinder and has a free end which is articulated to the movable jaw 6. In this variant, the use of an actuator which can swing both at the end which is restrained on the scoop-like body 2 and in the region of the movable jaw 6 avoids the use of the connecting rod 36.

The adjustment means 22 comprises a hydraulic circuit, not shown, for operating the hydraulic jack 30a, including distributor means for delivering oil to the chamber 37. In one variant of the invention, the distributor means is constituted by a distributor valve.

The hydraulic circuit of the adjustment means 22 comprises valve means constituted by a pressure regulator or by a maximum pressure valve for regulating the pressure in the chamber 37.

According to a variant of the invention, the valve means is interposed between the chamber 37 of the actuator 30 and the distributor means.

According to a further variant, the pressure-regulating valve means is connected to the delivery of the chamber 37.

The operation of the means 22 for adjusting the distance between the jaws 6, 7 in the variant according to the drawings is described below.

After the distance between the jaws 6,7 has been set by the insertion of a predetermined number of spacers 26 in the seat 24, oil is delivered to the chamber 37 so as to urge the piston 32, to which the rod 34 is firmly fixed, towards the base 31a of the cylinder 31. This leads to a movement of the seats 24, 25 towards one another and consequent clamping of the strut 23 and the spacers 26.

In order subsequently to change the distance between the jaws 6, 7, and consequently to adjust the crushing dimension for the material in the bucket, the valve means are acted on by means of a hydraulic switch which diverts the pressurized oil flow from the chamber 37 of the actuator 30 to the delivery. Since the piston 32 is not opposed by the fluid pressure, it is thus free to be drawn along due to gravity by the weight of the movable jaw 6, releasing the strut 23 and the spacers 26 as a result of the movement of the seats 24, 25 away from one another so that a different distance between the jaws 6, 7 can be set by changing the number of spacers 26. After this change has been performed, oil is delivered to the chamber 37 again so as once more to stiffen the assembly constituted by the spacers 26, the counterthrust strut 23 and the movable jaw 6.

In the variant of Figures 8 to 11, the adjustable tie 30 is a belt 30b having an eyelet 41 at one end 40 of the belt 30b. A pin 42 fixed firmly to the movable jaw 6 is inserted in the eyelet 41. The belt 30b is wound, at a second end 43 thereof onto a second pin 44 which is fixed firmly to the scoop-like body 2. The pin 44 has a knurled surface 45 in contact with the belt 30b. The knurling of the surface 45 facilitates adhesion by friction between the belt 30b and the pin 44.

The adjustment means 22 comprises a lever tensioning mechanism 46 for adjusting the belt 30b. The tensioning mechanism 46 comprises a lever 47 fixed firmly to the pin 44. In the variant of Figure 10b, the tensioning mechanism 46 comprises, at the end of the pin 44, a hexagonal head 44a, or a head of another shape, which can be coupled releasably with a drive key, not shown. The drive key has a lever arm the length of which can be increased at will to reduce the force to be applied to it by the user. In contrast, the length of the lever 47 is subject to dimensional constraints determined by the dimensions of the bucket 1.

In both of the embodiments described above, the tensioning mechanism 46 can be operated manually by a user, by rotation of the pin 44 about its axis in the direction which increases the winding of the belt 30b around the pin 44 (anticlockwise rotation in Figure 8) and consequently brings about movement of the seats 24, 25 towards one another and clamping of the strut 23 and the spacers 26. Opposite rotation in the direction which reduces the winding of the belt 30b around the pin 44 (clockwise rotation in Figure 8) is prevented by unidirectional locking means 48 connected to the tensioning mechanism 46. The locking means 48 comprise a pawl 50 which is restrained on the lever 47 so as to be slidable in a seat 51 and a plurality of teeth 49 fixed firmly to the pin 44 of the lever 47 and engageable by the pawl 50. The teeth 49 have an asymmetric shape with a rounded side such as to permit rotation in the direction which increases the winding of the belt 30b around the pin 44 and a straight opposite side which can be engaged by the pawl 50 so as to prevent rotation in the opposite direction.

The pawl 50 is of the quick-release type which can be operated manually in order to be moved along the seat 51 away from the teeth 49 in order to release them, permitting clockwise rotation of the pin 44 and consequent slackening of the belt 30b.

The operation of the adjustment means 22 in the variant of Figures 8 to 11 is described below.

After the width of the outlet aperture 5 has been set by the insertion of a suitable number of spacers 26, the pin 44 is rotated by means of the lever 47 to tension the belt 30b and clamp the strut 23 and the spacers 26 as a pack.

In order subsequently to change the width of the outlet aperture 5, the pawl 50 is operated so as to release the teeth 49 to allow the belt 30b to be unwound from the pin 44.

The seats 24, 25 move apart owing to gravity, releasing the strut and the spacers 26, so that the number of spacers 26 can be changed.

According to other variants, a cable or a chain can be used in place of the belt 30b, with similar operation.

In the variant of Figures 12 and 13, the adjustable tie 30 is a chain 30c comprising two chain sections 60, 61 having respective ends 60a, 61a which are restrained on the scoop-like body 2 and on the movable jaw 6, respectively.

In this latter variant, the adjustment means 22 comprises a screw coupling 62 defined between the two chain sections 60, 61 for adjusting the chain 30c.

The screw coupling 62 comprises two threaded pins 63, 64 which are disposed at the ends 60b, 61b that are remote from the ends 60a, 61a in the two chain sections 60, 61, respectively. One of the threads of the two pins 63, 64 is a right-hand thread and the other is a left-hand thread.

The screw coupling 62 comprises a central body 65 provided with two threaded cavities 66, 67 in which the respective pins 63, 64 can be engaged. A lever 68 fixed firmly to the central body 65 can be operated by a user in order to rotate the central body 65 in one direction and in the other relative to the two pins 63, 64. Owing to the two opposite directions of the threads connecting the pins 63, 64, to the central body 65, the rotation of the central body 65 in one direction leads to movement of the two pins 63, 64 towards one another whereas rotation of the central body 65 in the opposite direction leads to movement of the two pins 63, 64 away from one another.

The movement of the two pins 63, 64 towards one another leads to movement of the seats 24, 25 towards one another with consequent clamping of the strut 23 and of the spacers 26; the movement of the two pins 63, 64 away from one another releases the strut 23 and the spacers 26 so that the number of spacers 26 can be changed.

In another variant of the invention (not shown), a pneumatic actuator, for example, an air or nitrogen bellows, is used instead of the hydraulic jack 30a and the adjustment means comprises a pneumatic circuit for operating the pneumatic actuator.

The invention overcomes the disadvantages of the prior art mentioned by proposing a crusher bucket comprising an efficient adjustment system without a mechanical spring.

At the same time, the invention affords further advantages including, for the variants comprising a hydraulic jack or a pneumatic actuator, that of providing an adjustment system which can be connected to a control system. A further advantage is that of providing a quick-release adjustment system for quicker adjustment than in the prior art, in particular for the variants comprising the lever tensioning mechanism and the quick- release unidirectional locking means.

Finally, the Applicant has found that, in all of its variants, the invention effectively absorbs the vibrations of the system whilst using a tie which does not have a mechanical spring and is therefore not subject to the problems discussed with reference to the prior art mentioned.