Abstract:
A pitting machine comprises a punching head that performs a curvilinear oscillatory movement in synchronization with the translation movement of fruits to be pitted, in particular for use in industries that process food such as pitted dried or dehydrated plums and which are currently performing manual operations or using rudimentary equipment.

Description:
FIELD OF INVENTION  
       [0001]     The present invention relates to a pitting machine comprising a punching head which performs a curvilinear oscillatory movement in synchronization with the translation movement of fruits to be pitted. More specifically, it refers to an extraordinarily simple mechanism for the removal of pits from soft fruits such as dehydrated or fresh plums, dates, etc. This invention is particularly oriented to industries which process food such as pitted dried or dehydrated plums and which are currently performing manual operations or using rudimentary equipment.  
         [0002]     Basically, the working principle is to put each of the fruits in individual containers consisting of a pair of jaws able to open and close, such jaws allowing entering of one fruit only. Said fruit is then alternatively compressed in a same direction in an attempt of reducing its volume by reducing cross-section thereof. This kind of movement allows for the fruit to be positioned with its main axis parallel to the compression planes. One end of the fruit is placed on a rubber and a punch is introduced into the other end in order to remove pit.  
       BACKGROUND  
       [0003]     Plum and dates pitting equipment or apparatuses are known since more than twenty years, said equipment or apparatuses having been improved in terms of the mechanism actuating on the punch (punches) which penetrate the fruit, but said mechanism has always been based on a cam and eccentric. Said mechanisms, apart from requiring complex maintenance and being subject to wear, are unsafe per se, as they produce breakage of equipment parts which lead to extended periods for the repair thereof, with the corresponding costs. Also, such mechanisms, due to their conception, require lubrication, which may contaminate product. Even when using a food grade lubricant, foodstuff quality is reduced, as it typically can not be washed.  
         [0004]     Many of the previous art mechanisms use spring punching heads, said springs being compressed most of the time, thus requiring power. Also, when the motor stops said springs relax suddenly, thus adding a risk factor for machine operators. Spring punching heads are also difficult to calibrate, as the synchronism to be attained between the conveyor belt and the head descending movement is so complicated that at least two individuals are necessary in order to configure same.  
         [0005]     U.S. Pat. No. 5,619,912 discloses a pitting machine which conveyor belt is inclined as regards the horizontal plane, said machine includes a cam chamber able to rotate and which is associated to a pivot which carries out a pivoting movement in response to said cam box rotation and over which the punching head is associated. The whole assembly is positioned above the belt conveying fruits and inside the pitting machine.  
         [0006]     U.S. Pat. No. 5,870,949 discloses a pitting machine which punching head is directly related to an eccentric which is associated to a cam, such assembly being positioned above the belt conveying fruits and inside the pitting machine. This includes a cleaning blade mounted on the machine frame, which blade loosens pits from containers as these move away from the extraction area.  
         [0007]     Although it is desirable for the punch trajectory in pitting machines to be substantially perpendicular to the conveyor belt travel (and thence to the fruit travel), in order to provide a better extraction of pits the present invention provides a curvilinear trajectory of punch which exhibits a large curvature radius, which greatly resembles this kind of trajectory. The reason for this trajectory change is due to the novel combination of pit extraction mechanical elements employed, which confer the following advantages as regards prior art: they improve efficiency of the fruit pits extraction mechanism without requiring lubrication; they are placed outside the pitting machine, far from the fruit to be pitted; they use a spring-free punching head; they are formed with commercially available elements; pitting area is easily and safely accessed for inspection and cleaning purposes; they require low maintenance, requiring short machine shutdowns and long operating periods.  
       SUMMARY  
       [0008]     Accordingly, it is an object of the present invention a pitting machine comprising:  
         [0009]     a chassis;  
         [0010]     a loading area;  
         [0011]     an unloading area;  
         [0012]     fruit traction, vibration, selection, separation and orientation means associated to said chassis;  
         [0013]     a closed loop conveyor belt;  
         [0014]     a plurality of fruit containers that alternatively close and open, said containers being mounted on said closed loop conveyor belt;  
         [0015]     a punching head positioned over said closed loop conveyor belt, an end of said punching head including a plurality of spring-free punches; and  
         [0016]     actuating means for said punching head, which means consist of at least two eccentrics mounted on a central axis arranged under the pitting area, said at least two eccentrics being positioned external to said chassis and each of them being articulately connected to at least one crankshaft and to one of the ends of an horizontal connecting rod, said crankshaft being in turn connected to one of the ends of a vertical connecting rod and the other of said ends of said vertical connecting rod articulated to one of sides of the end of said punching head which includes punches, each of the sides of the other end of said punching head being articulately associated to one of the ends of an oscillating post placed externally to such chassis, and the other end of said oscillating post being articulated with a pivot axis rigidly mounted on said chassis; also, both oscillating posts comprise in some point between their two ends a projection on which the other end of said horizontal connecting rod articulates.  
         [0017]     The invention will be better understood when considered in reference to the drawings in which a preferred embodiment thereof is represented. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]      FIG. 1  is a side view of the pitting apparatus which is the object of this invention.  
         [0019]      FIG. 2  is a front view of the pitting apparatus which is the object of this invention.  
         [0020]      FIG. 3  is a perspective view of the fruit aligning and engagement system of the pitting apparatus which is the object of this invention.  
         [0021]      FIG. 4  is a side view of the punching mechanism of the pitting apparatus which is the object of this invention. A preferred embodiment of the plums or dates pitting machine of this invention is shown by  FIGS. 1 and 2 . The machine is constituted by a chassis  1  and widely known fruit traction, vibration, selection, separation and orientation means. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]     Said traction means are constituted by a main axis  3  mounted on bearings  2 . Said main axis  3  supports gears  4  on each of the ends thereof, each of said gears pull a pair of closed loop parallel chains  5  which connect said main axis  3  to rear axis  6 , intermediate axis  7  and return axis  8 . Main axis  3  has a crown or gear  9  controlled or driven by a gear or pinion  10  which is mounted on a central axis  12  by means of a chain  11 . Said central axis  12  is mounted on bearings  13  and is arranged under the pitting area  23 . Said central axis  12  is controlled or driven through a gear  14  by means of chain  15  of a driving pinion  16  which is directly coupled to the overstress clutch of a reducing motor  18 .  
         [0023]     Traction means are in turn associated to a closed loop conveyor belt  17  housing fruit  25  containers  19 . Said containers  19  are displaced from the loading area consisting of a loading bin  20 , passing along the fruit  25  selection means constituted by rejecting brushes  21 , which allow entering of one fruit  25  into each container  19  of the conveyor belt  17 , passing then through fruit orientation means  22  and up to the pitting area  23  where there are separation means  30  and a plurality of punches  24  possessing an oscillatory movement which is almost perpendicular to conveyor belt  17 . Said punches  24  pierce moving fruits  25  and remove pits  26 . Conveyor belt  17  continues advancing towards the front of the machine and commences its return at the unloading area  28 , where pitted fruits  25  fall under gravity. Unloading area  28  comprises an unloading bin  27  complemented by a sector  29  comprising a cam  31  which confers vertical vibration onto conveyor belt  17  in order for it to expel those fruits  25  not expelled at the unloading bin  27  itself.  
         [0024]     Selection means are conformed by rejecting brushes  21  which are driven through said intermediate axis  7 , which is actuated by effect of the same conveyor belt  17  which rests its chains  5  on gears  32 . Said intermediate axis  7  bears another gear  33  mounted over it and which through chain  34  confers rotation to smaller gears  35  in turn mounted on the rejecting brushes axes  21 .  
         [0025]     On the other hand, there are also included vibration means at the loading area which favour entering of each of the fruits  25  into containers  19 . Said vibration means are comprised of a motor  36  associated to a pulley  37  that through belt  38  rotates vibration axis  39  through pulley  40 . Vibration axis  39  rests on bearings  41  and possesses in the central part thereof an eccentric counterweight  42  that upon rotation generates an orbital vibration which is transmitted to vibration axis  39  and this in turn to bearings  41  which are associated to tracks  43  where conveyor belt  17  is supported. Said tracks  43  also rest on regulators  44  which purpose is to limit and regulate vibration of tracks  43  and thus obtain the maximum yield in terms of fruits  25  entering into each of the containers  19 .  
         [0026]     On the other side, separation means  30  are placed above said fruit  25  containers  19  and under said punching head  61 . Said separation means  30  are constituted by a plurality of parallel flat rods  66  spaced one from each other by a distance smaller than the diameter of each container  19  and larger than the diameter of each punch  24 . Separation means  30  allow separation of fruits  25  from punches  24  after pitting.  
         [0027]     As can be seen on  FIG. 3 , orientation means are constituted by a tablet  45  laterally associated to said chains  5  by means of screws  47 . Said tablet  45  houses rubber supports  46  and is associated to bearings  48  by means of special screws  49  which are adjusted on said screw  47  head. These bearings  48  support prune buckets  50  rigidly connected to an axis  51  and the latter, in turn, is rigidly connected to pushing die  52  on one end and axially slidable on the other. This kind of connection allows axial opposite movement between pushing dies  52  of both ends of said axis  51 . Axial movement of each prune bucket  50 /axis  51  assembly is enabled through rolls  53  and bolts  54 .  
         [0028]     Upon the translation movement of conveyor belt  17 , roll  53  rests on cam tracks  55  and thus compresses or reduces the space between prune buckets  50 , and by means of a spring  56  it is able to alternatively open and close, and in this manner there is attained, first, orientation of fruit  25  and then holding thereof upon pitting and further, the discharge thereof after pitting is accomplished. Optionally and as a complement a tablet cover  57  may be included, which cover is screwed on bearings  48 .  
         [0029]     As previously mentioned, one of the ends of punching header  61  bears spring-free punches  24 , which carry out an orbital type movement and during their trajectory should pierce fruits  25  within full translation movement. In order to attain such a synchronism, as can be seen on  FIG. 4 , the inventive machine has the following combination of mechanical means: at least two eccentrics  59  mounted on a central axis  12  arranged under the pitting area  23 , said at least two eccentrics  59  being located externally to said chassis  1 , and each of them being articulately connected to at least one crankshaft  58  and to one end of horizontal connecting rod  64 , said crankshaft  58  being in turn connected to one end of a vertical connecting rod  60  and the other end of said vertical connecting rod  60  being articulately connected to one of the sides of the end of said punching head  61  which includes punches  24 , each of the sides of the other end of said punching head  61  being articulated to one of the ends of an oscillating post  62  placed externally to said chassis  1 , and the other end of said oscillating post  62  being articulated to a pivot axis  63  rigidly mounted on said chassis  1 ; both oscillating posts  62  also comprising at some point between their ends a projection  65  on which the other end of said horizontal connecting rod  64  articulates.  
         [0030]     This combination of means, and more particularly the location of pivot axis  63  allows punches  24  to perform a curvilinear oscillating movement which is not perpendicular to the machine direction but does not affect pitting efficiency. In fact, said oscillating movement draws a large radius curve, which renders said movement substantially rectilinear. It may also be appreciated on said  FIG. 4  an orbital diagram illustrating the trajectory of the end of a punch  24 .