Patent Publication Number: US-7222807-B2

Title: Bucket for crushing and screening stone

Description:
TECHNICAL FIELD 
   The present invention relates to a bucket for crushing and screening stone and similar materials. 
   TECHNOLOGICAL BACKGROUND 
   In the technical field in question, self-propelled vehicles equipped with buckets for collecting material such as stone or the like, inside which a crushing mechanism is provided for crushing the material collected to the desired size, are known. 
   Amongst others, an example of a known crushing mechanism comprises two jaws, of which one moves pivotably relative to the other. The jaws are moved in a manner such as to compress between them, and hence to crush, the material which is introduced into the bucket. However, this crushing mechanism leads to some disadvantages which result in poor performance and non-homogeneity in the processing of the material treated. Known buckets therefore have high power consumption and are subject to blockage due to choking with the material introduced. 
   Stone crushing devices are known from U.S. Pat. No. 3,959,897, U.S. Pat. No. 1,954,288 and DE 580475. The first document discloses an excavating bucket having a vibrating cutter head and a crusher including a pair of jaws that are moved toward one another by an eccentric oscillating shaft. The shaft oscillation is so limited as to produce just an up-and-down movement of the jaws. 
   SUMMARY OF THE INVENTION 
   The main object of the present invention is to provide a bucket for crushing and screening stone and similar materials in which the crushing operation is particularly effective and efficient. 
   A further object is to provide a bucket in which the size of the crushed material is easily adjustable. 
   Another object is to produce a bucket which is subject to little or no obstruction due to blockage with the material treated. 
   Yet another object is to produce a bucket which can be adapted to a plurality of self-propelled vehicles and which can easily be produced in many different sizes. 
   A further object is to provide a bucket which permits optimal, in particular homogeneous, crushing of a plurality of different materials. 
   The objects proposed are achieved by the present invention by providing a bucket including a scoop-shaped body. The body defines an inlet opening for the stone to be crushed and an outlet for the crushed stone, between which a direction of flow of the stone is defined. The mechanism for crushing the stone has a first jaw and a second jaw housed in the scoop-shaped body and movable relative to one another, and an element for moving the first jaw relative to the second jaw. The element can impart to the first jaw a combined rotational and translational movement relative to the second jaw, in which a first component of the movement is away from and towards the second jaw and a second component of the movement is substantially parallel to the direction of flow. 
   It is to be understood that both the foregoing general description and the following detailed description are exemplary, but are not restrictive, of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The characteristics and the advantages of the invention will become clearer from the detailed description of two embodiments thereof, described by way of non-limiting example with reference to the appended drawings. It is emphasized that, according to common practice, the various features of the drawings are not to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Included in the drawings are the following figures: 
       FIG. 1  is a partially sectioned side view of a bucket according to the invention, 
       FIG. 2  is a partially sectioned plan view of the bucket of  FIG. 1 , 
       FIG. 3  is a partially sectioned front view of the bucket of  FIG. 1 , 
       FIG. 4  is a view showing a detail of a further embodiment of the bucket of  FIG. 1 , on an enlarged scale, and 
       FIG. 5  is a view of the detail of  FIG. 4  in a further operative position. 
   

   PREFERRED EMBODIMENTS OF THE INVENTION 
   In the drawings, in which like reference numbers refer to like elements throughout the various figures that comprise the drawings, a bucket formed in accordance with the present invention is generally indicated by reference number  1 . 
   The bucket  1  is arranged for connection, in a known manner, to one or more arms of a self-propelled vehicle (not shown). 
   The bucket  1  comprises a scoop-shaped body  2  having an inlet opening  3  for the loading of broken stone, pebbles, stones, and the like and having a cross-section which is enlarged in comparison with an opposed outlet opening  4  for the discharge of the material treated, after crushing and screening. 
   A stone-crushing mechanism is mounted in the scoop-shaped body  2  and comprises a movable crushing jaw  5  and an opposed fixed crushing jaw  6  fixed firmly to the body  2 . Both the movable jaw and the fixed jaw  5 ,  6  include respective frames  5   a ,  6   a  on which plates  5   b ,  6   b  are fitted removably; the plates  5   b ,  6   b  are provided with longitudinal grooves, all indicated  20 , extending parallel to the direction of flow of the stone introduced and suitable for facilitating the crushing thereof. The grooves  20  define a plurality of ribs  20   a  and recesses  20   b , alternating in succession in a manner such that a rib  20   a  of the movable jaw  5  corresponds to a recess  20   b  of the fixed jaw  6 , so that, during the movement of the first movable jaw  5 , the crushing of the material is homogeneous. Moreover, since the ribs  20   a  of one jaw can penetrate the recesses  20   b  of the other jaw, the crushing can be particularly fine. 
   The plates  5   b ,  6   b  are reinforced and restrained, by respective undercuts, through the provision of retaining strips  40 . 
   Respective first and second opposite ends  7 ,  8  are defined in each of the jaws  5 ,  6 , the first ends  7  of the fixed and movable jaws  6 ,  5  being positioned in the region of the inlet opening  3 , and the second ends  8  being positioned in the region of the outlet opening  4 . The distance between the first ends  7  of the jaws  5  and  6  determines the maximum size of the stone which can be loaded into the bucket  1  and is greater than the distance between the second ends  8  which, on the other hand, is correlated with the desired maximum size of the crushed stone at the outlet opening  4 . Both the distance between the first ends  7  and the distance between the second ends  8  are adjustable, as explained in detail below. 
   The bucket  1  also has an element for moving the movable jaw  5 , including a drive mechanism  9 , for example, a hydraulic motor, which is housed inside the scoop-shaped body  2  and drives a drive shaft  10  on which a first pulley  11  is keyed. The rotary movement of the first pulley  11  is transmitted, through a belt transmission  12 , to a second pulley  13 , keyed to a shaft  14 . 
   A first eccentric  15  and a second eccentric  16  are arranged on the shaft  14 , in phase with one another, and each is coupled with a respective first or second bearing  17 ,  18 . A hollow sleeve  19  is fitted on the two bearings  17 ,  18  so as to be freely rotatable relative thereto and the movable jaw  5  is fixed, in the region of its first end  7 , to the outer surface  19   a  of the sleeve  19 , so as to be moved by the shaft  14  together with the sleeve  19 . 
   The drive mechanism  9  is also arranged, when necessary, to drive a vibrator  50  acting on the fixed jaw  6  and disposed in the region of the inlet opening  3 , for bringing about pulsed vibrations of the jaw  6  so as to release any material which has become stuck. 
   The bucket  1  also comprises an adjuster  22  for changing the movement of the movable jaw  5  and the size of the cross-section of the outlet opening  4 . The adjuster  22  comprises a strut  23  interposed and restrained between respective first and second channels  25 ,  33 , of which one is mounted on the frame  5   a  of the movable jaw  5  and the other on a support  41  fixed firmly to the scoop-shaped body  2 . The ends  24   a ,  24   b  of the strut  23  which are housed in the channels  25 ,  33  are rounded to facilitate their pivoting about the respective contact lines. 
   A set of removable spacers  34  is interposed between the support  41  and the corresponding second channel  33  for the adjustment of the size of the cross-section of the outlet opening  4 . The second channel  33  is welded to the end spacer. 
   In a first embodiment of the invention of  FIG. 1 , the channel  33  is welded centrally to the end spacer whereas, in a further embodiment shown in  FIGS. 4 and 5 , the channel  33 ′ is welded in the region of an edge of the spacer. By varying the position of the second channel  33 ,  33 ′ relative to the end spacer, the angle between the movable jaw  5  and the strut  23  can in turn be adjusted in order to vary in the manner described below. By virtue of the characteristics just described, the strut  23  can be positioned in three different operative positions: a first, central operative position, in which the second channel  33  is spaced equally from two opposed walls  35   a ,  35   b  of the support  41 , and which can be achieved with the use of the channel  33  welded as shown in  FIG. 1 ; a second operative position in which the channel  33 ′ is close to the first wall  35   a ; and a third position in which it is close to the second wall  35   b , which can be achieved, from the second operative position, by removing the spacer and channel  33 ′ and reinserting them having rotated them through 180° (thus changing from the operative position of  FIG. 4  to that of  FIG. 5 ). According to the operative position selected, the angle formed between the strut  23  and the movable jaw  5 , in particular, the angle between an axis Y joining the center of rotation of the second pulley  13  and the point P at which the strut  23  is supported in the first channel  25 , and an axis Z of the strut  23  extending through the support point P, is varied. This angle is 45°, 40°, and 50° in the three operative positions listed above, respectively. 
   The bucket  1  also comprises a resilient mechanism, in particular, a spring  30 , a first end of which is connected to the scoop-shaped body  2 , and a second, opposite end of which is connected to the second end  8  of the movable jaw  5 , so as to keep the strut  23  restrained between the first and second channels  25 ,  33  (or  33 ′) during the movement of the jaw  5 . A mechanism  51  for adjusting the load exerted by the spring  30 , such as a screw coupling system, is also provided on the scoop-shaped body  2 . 
   The bucket  1  according to the exemplary embodiments of the invention operates as follows. 
   The stone or other material to be crushed is collected by the bucket  1  in a conventional manner. In order to send the material collected towards the jaws  5 ,  6 , the bucket  1  is pivoted through  900  from the position in which it is shown in  FIG. 1 , that is, the outlet opening  4  is arranged at a height below the inlet opening  3  so that the material is urged towards the jaws  5 ,  6  simply by the effect of gravity. 
   The flow of material is facilitated with the use of the vibrator  50 , even if the inlet opening  3  is positioned at the same height as the outlet opening  4 . 
   The movable jaw  5  is moved by operation of the hydraulic motor (a particular embodiment of the drive mechanism  9 ) which transfers the movement from the first pulley  11  to the second pulley  13  and consequently to the shaft  14 . Owing to the effect of the two eccentrics  15 ,  16 , the hollow sleeve  19 , which is freely rotatable on the bearings  17 ,  18 , can perform a rotational/translational movement relative to the axis of the shaft  14 ; in particular, the first end  7  of the movable jaw  5 , which is fixed to the sleeve  19 , is moved from a first position, in which the inlet opening  3  has a maximum cross-section, to a second, opposite position which differs from the first by a rotation of the eccentrics  15 ,  16  through 180°, and in which the inlet opening  3  has a minimum cross-section. The first end  7  of the movable jaw  5  adopts all of the intermediate positions between the above-defined first and second positions, during its rotational/translational movement. 
   Since the movable jaw  5  is a rigid body, movements of the first end  7  result in corresponding movements of the second end  8  which, however, is restrained by the spring  30  and by the strut  23 . The movements of the end  8  are permitted by the pivoting of the ends  24   a ,  24   b  of the strut  23  within the first and second channels  25 ,  33  ( 33 ′), respectively, so that the inclination of the strut  23  relative to the jaw  5  is varied continuously during the movement of the movable jaw  5 . The resulting movement comprises a component substantially perpendicular to the movable jaw  5  and a component parallel thereto, along the direction of flow of the stone, in a manner similar to a “chewing” motion, promoting crushing of the stone and its movement towards the outlet opening  4 . 
   The maximum size of the cross-section of the outlet opening  4  can also be adjusted by increasing or reducing the number of spacers  34  located inside the support  41 , thus varying the maximum size of the crushed stone. 
   The movement of the movable jaw  5  can also be modified, thus changing the characteristics of the crushing due to the relative movement of the jaws  5 ,  6 , by varying the inclination between the strut  23  and the movable jaw  5  at rest, as described above. With the use of the configuration shown in  FIG. 4 , in which the inclination between the strut  23  and the movable jaw  5  is least, the movement of the end  8  of the movable jaw  5  comprises a considerable translational component in the direction of the flow of the material, thus facilitating the movement of the material towards the outlet opening  4 . This position is therefore particularly suitable when materials which form blockages easily, for example, moist or fine-grained materials, are being processed. The positioning shown in  FIG. 5 , which can be achieved by rotating the channel  33 ′ welded to the spacer  34  through 180°, on the other hand, is particularly suitable when a considerable crushing power is required. 
   The invention thus achieves the objects proposed, also affording numerous advantages over the known devices referred to. 
   A first advantage afforded by the bucket according to the invention is that it is possible to optimize the crushing of the stone by virtue of the plurality of adjustments permitted, by adjusting the relative movement of the jaws in dependence on the material. 
   Moreover, the size of the crushed stone can easily be adjusted. 
   One of the main advantages is that the power consumption of the bucket according to the invention is less than that of conventional buckets, by virtue of the greater efficiency achieved by the process, which also leads to a reduction in processing time and to a reduction in noise emitted. 
   Moreover, the crushing performed by the above-described bucket is particularly uniform. 
   One of the main advantages is that, by virtue of the type of movement of the jaw and of the provision of a vibrator, blockages of material and consequent stoppages of the processing are minimized. 
   Although illustrated and described above with reference to certain specific embodiments and examples, the present invention is nevertheless not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the spirit of the invention.