Patent Publication Number: US-2023152145-A1

Title: Combination scale

Description:
TECHNICAL FIELD 
     This invention relates to a combination scale that weighs and combine target items to be weighed into a combination of items having a summed weight that falls within a predetermined range of weights and then discharges the items thus weighed and combined. 
     BACKGROUND ART 
     The combination scales may be roughly divided into three different types of scales; automatic scales, semiautomatic scales, and manually operated scales, in accordance with how items to be weighed are supplied to and discharged from their weighing units. The manually operated combination scales require manpower for both of the supply and discharge of the items. The semiautomatic combination scales receive items that are manually supplied and mechanically discharge the received items. In the automatic combination scales, both of the supply and discharge of items are automated without the need to rely on manpower. 
     The manually operated or semiautomatic combination scales may be selected for any items to be weighed and supplied that are difficult or unsuitable for automatic handling. 
     Patent Literature 1 describes an example of the semiautomatic combination scales of the known art. In this combination scale, weighing conveyers are horizontally arranged in a row and are manually supplied with items to be weighed. A combination of discharge-target weighing conveyers containing the items having a summed weight that falls within a given range of weights is selected through combinatorial computations executed based on weights of the items received by the weighing conveyers. The selected combination of weighing conveyers is driven to discharge the items into a collection conveyer, and the collection conveyer transports the items along the direction of arrangement of the weighing conveyers. With this collection conveyer, the items of a weight that falls within a given range of weights are transported and discharged into a packaging machine disposed in a later stage of the scale. 
     CITATION LIST 
     Patent Document 
     
         
         Patent Document 1: JP 2018-66600 A 
       
    
     SUMMARY OF THE INVENTION 
     Technical Problems 
     Such a semiautomatic combination scale may involve the risk that a person who operates the scale standing in front of the weighing conveyers accidentally contacts transport-starting ends of the conveyers. To avoid that, the combination scale of this type may be typically equipped with a cover for protection. This protective cover is disposed on the transport-starting side of the weighing conveyers and is coupled with screws to the body of the combination scale. 
     In the weighing conveyers and the protective cover are often left broken pieces or scraps of the items, for example, foodstuffs. The protective cover, therefore, should desirably be easily opened for cleaning. 
     As described earlier, the collection conveyer transports the items discharged from the weighing conveyers, and a control box containing a power supply unit and a control board is disposed at a position below this collection conveyer. The broken pieces or scraps of the items, while being delivered from the weighing conveyers into the collection conveyer, may possibly drop onto the upper surface of the control box and stay there. 
     Cleaning, which is naturally required of any combination scales used to handle and weigh foodstuffs, may remove such broken pieces or scraps of the items left on the upper surface of the control box. Yet, cleaning water used then may be often left on the control box, possibly posing hygiene-related risks. 
     This invention was accomplished to address these issues of the known art and is directed to providing a combination scale allowed to facilitate maintenance including cleaning. 
     Technical Solution 
     To this end, the present invention provides the following technical aspects. 
     1] A combination scale according to this invention includes: a plurality of weighing conveyers arranged in a row, the weighing conveyers transporting items to be weighed that are manually supplied; a collection conveyer that transports the items discharged from the weighing conveyers along a direction of arrangement of the weighing conveyers; and a protective cover disposed on an outer side of transport-starting ends in a direction of transport of the weighing conveyers, the protective cover extending in the direction of arrangement of the weighing conveyers. The protective cover is supported in a manner that is rotatable to and from a closing position and an opening position, the closing position being a position at which the protective cover faces the transport-starting ends in the direction of transport, the opening position being a position at which the protective cover is rotated outward. 
     In the combination scale according to this invention, the protective cover disposed for protection of the weighing conveyers is long in the direction of their arrangement and is accordingly relatively heavy. This protective cover, however, needs not be removed and readily opens and closes through simple rotations, facilitating maintenance of the combination scale including cleaning. 
     2] In a preferred embodiment of this invention, a plurality of groups of the weighing conveyers are disposed on both sides of the collection conveyer, and the plurality of groups of the weighing conveyers are each provided with the protective cover. 
     According to this embodiment, the collection conveyer may be reduced in length by having the weighing conveyers disposed on both sides of the collection conveyer. This may lead to the following advantages; reduction of time required to discharge the items, downsizing of the combination scale, and reduced length of the protective cover serving to cover the weighing conveyers. The protective cover thus reduced in length may be easier to handle. 
     3] In other embodiments of this invention, the protective cover is rotatably supported through a torque hinge. 
     According to this embodiment, the rotational resistance of the torque hinge alone may allow the protective cover to stay at the closing and opening positions. Thus, the protective cover may be easier to handle without the need to use any particular locking means. 
     4] In other embodiments of this invention, the combination scale further includes, at a position below the protective cover, a control box that rotatably supports the protective cover. 
     According to this embodiment, the control box is disposed at, instead of a position below the collection conveyer as in the known art, a position below the protective cover on the outer side of the transport-starting ends of the weighing conveyers. This leaves an unoccupied open space below the collection conveyer. 
     When the weighing conveyers are supplied with the items and the items in the weighing conveyers are delivered into the collection conveyer, any broken pieces or scraps of the items, if they fall from the weighing conveyers or the collection conveyer, may be likely to drop onto the floor surface. Thus, such broken pieces or scraps of the items and/or cleaning water may be unlikely to drop onto the upper surface of the control box and stay there, and the combination scale may be accordingly kept in a sanitary condition. 
     5] In other embodiments of this invention, the upper surface of the control box is an inclined surface inclining downward toward an outer side of the control box. 
     According to this embodiment, cleaning water is guided downward along the inclined upper surface of the control box and then finally discharged. Thus, cleaning water may be unlikely to remain on the upper surface of the control box, and the combination scale may be accordingly kept in a sanitary condition 
     6] In other embodiments of this invention, an interval is formed between an upper outer edge of the control box and the protective cover at the opening position. 
     When the protective cover is shifted to the opening position to start cleaning, cleaning water used then may be allowed to smoothly run downward through the interval between the protective cover at the opening position and the upper part of the control box. Thus, the cleaning work may be performed more efficiently. 
     7] In other embodiments of this invention, the protective cover includes a plurality of display lights each used for a respective one of the weighing conveyers. 
     According to this embodiment, the display lights for all of weighing conveyers are collectively disposed in the protective cover. This may simplify a wiring work and facilitate a waterproof treatment, as compared with the display lights being disposed alongside the weighing conveyers. 
     Effects of the Invention 
     As described thus far, the combination scale according to this invention is equipped with the protective cover for the weighing conveyers. This protective cover needs not be removed and readily opens and closes through simple rotations. This may facilitate maintenance of the combination scale including cleaning 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a combination scale according to an embodiment of this invention. 
         FIG.  2    is a plan view of the combination scale illustrated in  FIG.  1   . 
         FIG.  3    is a front view of the combination scale illustrated in  FIG.  1   . 
         FIG.  4    is a perspective view of the combination scale when protective covers are opened. 
         FIG.  5    is a plan view of the combination scale when the protective covers are opened. 
         FIG.  6    is a front view of the combination scale when the protective covers are opened. 
         FIG.  7    is a perspective view of the combination scale from which weighing conveyers have been removed. 
         FIG.  8    is a perspective view of the weighing conveyer. 
         FIG.  9    is a plan view of the weighing conveyer. 
         FIG.  10    is a side view of the weighing conveyer. 
         FIG.  11    is a plan view of conveyer frames in the weighing conveyers. 
         FIG.  12    is a longitudinal front view of the conveyer frame. 
         FIG.  13    is an exploded perspective view of the conveyer frame. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of this invention are hereinafter described in detail with reference to the accompanying drawings. 
       FIG.  1    is a perspective view of a combination scale  1  according to an embodiment of this invention.  FIG.  2    is a plan view of the combination scale.  FIG.  3    is a front view of the combination scale. 
     The combination scale  1  according to this embodiment is a semiautomatic combination scale. An operator manually supplies this combination scale with items to be weighed, and the combination scale mechanically discharges the items having a weight that falls within a predetermined range of weights. The combination scale  1  includes a collection conveyer  2 , a plurality of weighing conveyers  3 , an operation setting displayer  4  of touch panel type, and a pedestal  5 . The collection conveyer  2  includes a belt conveyer that transports the items in a direction of transport A. The weighing conveyers  3  each including a belt conveyer are arranged in rows on both sides of the collection conveyer  2 . The operation setting displayer  4  displays thereon operation statuses and parameter settings for operation control of the combination scale  1 . These devices are supported by the pedestal  5 . 
     The collection conveyer  2  transports the items having a weight that falls within a predetermined range of weights and that have been discharged from the weighing conveyers  3 . The collection conveyer  2  then discharges the items into a packaging machine disposed in a later stage of the scale. The discharged items will be packed into bags in the packaging machine. 
     The weighing conveyers  3  arranged in two rows; seven weighing conveyers in each row in the illustrated example, are disposed as weight measuring units on lateral sides of the collection conveyer  2  along the direction of transport of this conveyer. The weighing conveyers  3  of the respective rows are linearly arranged on both sides of the collection conveyer  2 . The weighing conveyers  3  transport the items in a direction of transport B orthogonal to the direction of transport A of the collection conveyer  2 . 
     The weighing conveyers  3  are detachably supported by load measuring units  6  arranged in rows in an upper part of the pedestal  5 . The weight of the weighing conveyer containing the items is detected by a weight sensor, like a load cell, embedded in the load measuring unit  6 , and the detected weight is transmitted to a controller not illustrated in the drawings. The weighing conveyer  3  is driven by a driving motor embedded in the load measuring unit  6 . 
     An operator manually feeds the items into the empty weighing conveyers  3  currently inactive. The weight of each weighing conveyer  3  is detected by the weight sensor. Based on the detection output of the weight sensor, the controller not illustrated in the drawings obtains weight values of the items and executes combinatorial computations. The combinatorial computations variously combine the weights of the items in the weighing conveyers  3  and then select, as discharge-target weighing conveyers, a combination of weighing conveyers having a summed weight that falls within a predetermined range of weights. In case there are two or more combinations of discharge-target weighing hoppers having a summed weight that falls within a predetermined range of weights, one of the combinations is selected that has a smallest absolute value of a difference between the obtained combined weight and a target combined weight. The items in the weighing conveyers  3  selected for discharge are transported and discharged onto the collection conveyer  2  by the weighing conveyers  3 . The items on the collection conveyer  2  are then transported out of the collection conveyer  2  into the packaging machine. 
     For clear and easy understanding of what is described herein, the following directions are hereinafter defined as; “lateral direction” as the direction of arrangement of the weighing conveyers  3  (longitudinal direction of the collection conveyer  2 ), and “front-back direction” as the longitudinal direction of the weighing conveyers  3 . 
     Control boxes  7  are disposed at positions outward and below the weighing conveyers  3  on both sides of the collection conveyer  2 , i.e., at positions on the outer side of transport-starting ends in the direction of transport of the weighing conveyers  3 . The control boxes  7  are supported by the pedestal  5  and these control boxes each include a power supply unit and a control board. By thus having the control boxes  7  disposed outward and below the weighing conveyers  3  on both sides of the collection conveyer  2 , there is an unoccupied open space below the collection conveyer  2 . 
     Thus, any broken pieces or scraps of the items, if they fall from the weighing conveyers  3  or the collection conveyer  2 , may be invited to drop onto the floor surface. Such broken pieces or scraps of the items and/or cleaning water may be unlikely to stay on the upper surface of the control box, and the combination scale may be kept in a sanitary condition. 
     The open space left unoccupied below the collection conveyer  2  and the load measuring units  6  may offer a large working area for maintenance and cleaning of the collection conveyer  2 . 
     Long protective covers  8  are attached to upper parts of the respective control boxes  7  to cover these control boxes. The protective covers  8  are located between the weighing conveyer  3  and an operator who manually supplies the weighing conveyers  3  with the items to be weighed. These protective covers, therefore, may successfully prevent accidental contact of the operator with a driving unit or transport-starting end of the weighing conveyer  3 . This may avoid the risk of errors in weighing the items using the weighing conveyers  3  and may also ensure an improved safety. 
       FIG.  4    is a perspective view of the combination scale  1  when the protective covers  8  are opened.  FIG.  5    is a plan view of the combination scale  1  when the protective covers  8  are opened.  FIG.  6    is a front view of the combination scale  1  when the protective covers  8  are opened. 
     As illustrated in  FIG.  5   , the protective covers  8  are attached rotatably and supportably to the upper parts of the control boxes  7  through a plurality of hinges  9 . As illustrated in  FIGS.  1  to  3   , the protective covers  8  are each allowed to shift to and from a closing position and an opening position. At the closing position, the protective cover is pulled upward to close. At the opening position, the protective cover is rotated downward and outward to open (away from the collection conveyer  2  at the center). The protective cover  8  at the closing position is close to and facing the transport-starting ends in the direction of transport of the weighing conveyers  3 . The protective cover  8  at the opening position exposes its inner surface and also exposes the load measuring units  6  and the transport-starting ends in the direction of transport of the weighing conveyers  3 . 
     The hinge  9  is a torque hinge that imparts an appropriate level of resistance to the rotation of the protective cover  8 . The protective covers  8  using such torque hinges may be allowed to stay at both of the closing and opening positions in a stable manner. 
     By having the protective covers  8  rotated outward and kept at the opening positions, The side plates of the control boxes  7  are allowed to fit in and out of these boxes from the outer side. 
     The protective covers  8  have, on their upper surfaces, display lights  10  that are disposed correspondingly to the weighing conveyers  3 . Further, the protective covers  8  each have an emergency stop button  11 . The display light  10  notifies the operator that the items in the relevant weighing conveyer  3  have a weight beyond a range of optimal weights, inviting the operator to resupply or change the items. These display lights  10  and the emergency stop buttons  11  are waterproofed and then connected to the control boxes  7 . 
     The protective covers  8  are kept at the closing positions during the normal operation but are opened when cleaning starts. Then, the weighing conveyers  3  are removed to wash off any broken pieces and scraps of the items. The control boxes  7  each have an upper surface  7   a  inclining downward toward the outer side, as illustrated in  FIG.  6   . Further, an interval c for water drainage is formed between the opened protective cover  8  and an outer edge in the upper part of each control box  7 , as illustrated in  FIGS.  5  and  6   . Thus, cleaning water may be guided to run outward and downward along the inclining upper surface  7   a  of the control box  7  to be finally discharged through the interval c. This may avoid the risk of the cleaning water being left on the upper surface  7   a  of the control box  7 . 
     Next, structural features of the weighing conveyers  3  are described below. 
       FIG.  7    is a perspective view of the combination scale  1  from which the weighing conveyers  3  have been removed.  FIG.  8    is a perspective view of the weighing conveyer  3 .  FIG.  9    is a plan view of the weighing conveyer  3 .  FIG.  10    is a side view of the weighing conveyer  3 .  FIG.  11    is a plan view of conveyer frames  21  in the weighing conveyers  3 .  FIG.  12    is a longitudinal front view of the conveyer frame  21 .  FIG.  13    is an exploded perspective view of the conveyer frame  21 . 
     The weighing conveyer  3  has a driving roller  22 , a tension roller  23 , and a wide conveyer belt  24 . The driving roller  22  is pivotally supported on the transport-starting side in the direction of transport of the conveyer frame  21 . The tension roller  23  is pivotally supported on the transport-ending side in the direction of transport of the conveyer frame  21 . The conveyer belt  24  is wound around the driving roller  22  and the tension roller  23 . 
     A driven gear  25  is coupled to one end of the driving roller  22 , as illustrated in  FIGS.  10  and  11   . This driven gear  25  is meshed, from the upper side, with a driving gear  26  of the load measuring unit  6 . The driving gear  26  is interlocked with a driving motor housed in the load measuring unit  6 , though not illustrated in the drawings. The driving gear  26  is exposed upward in an upper part of the load measuring unit  6 . 
     As illustrated in  FIG.  13   , the conveyer frame  21  includes a top plate  21   b  and a pair of side plates  21   a  facing each other. The side plates  21   a  and the top plate  21   b  are made of metallic, plate-shaped materials, for example, stainless steel and are integrally formed by press working. The driving roller  22  is disposed across the side plates  21   a  at one end (rear end) of the conveyer frame  21  and is pivotally supported in a freely rotatable manner. The tension roller  23  is disposed across bearing brackets  27  coupled to the side plates  21   a  at the other end of the conveyer frame  21  and is pivotally supported in a freely rotatable manner. The tension roller  23  is also slidably and elastically biased outward by a spring-embedded tension mechanism  29 . An item-feeding guide  28  is detachably mounted to the conveyer frame  21 . The item-feeding guide  28  serves to prevent the items from falling off the conveyer and is so shaped that extends substantially upright on both sides in the direction of width of the conveyer belt  24  and on the transport-starting side in the direction of transport. 
     The driving roller  22  and the tension roller  23 , though their detailed structural features are not illustrated in the drawings, are supported through bearings in a freely rotatable manner by support shafts inserted along their shaft centers. Both ends of the support shaft of the driving roller  22  are secured to the side plates  21   a  of the conveyer frame  21 . The support shaft of the tension roller  23  is inserted through and supported by the bearing bracket  27  in a manner that the support shaft is slidable back and forth but is not rotatable. 
     A gear housing  21   c  containing the driven gear  25  of the driving roller  22  is formed continuous to one end of one of the side plates  21   a  of the conveyer frame  21 . This gear housing  21   c  has such a protruding shape that covers and hides the driven gear  25  from the outer side and also from the upper side. The gear housing  21   c  has an open lower end, so that a lower end of the driven gear  25  is allowed to mesh with an exposed upper end of the driving gear  26 . 
     The top plate  21   b  of the conveyer frame  21 , through sliding contact, guides a transport-side inner peripheral surface of the conveyer belt  24 . The top plate  21   b  has a groove  30  formed along its entire length at a laterally middle position. As illustrated in  FIGS.  11  and  12   , the conveyer belt  24  has, on its inner peripheral surface, a guiding projection  24   a  formed to prevent meandering movements. The groove  30  serves to avoid any interference with this guiding projection  24   a  and also serves as a rib for better rigidity of the whole conveyer frame  21 . 
     From each of the bearing brackets  27  is extended a cantilever-type belt guide  27   a  to prevent sagging of the conveyer belt  24  between the tension roller  23  and the top plate  21   b.    
     The top plate  21   b  of the conveyer frame  21  has a plurality of circular openings  31  formed in a staggered manner. The formation of such openings achieves two objects; reduction of the area of contact of the top plate  21   b  with the conveyer belt  24  for less sliding resistance, and reduction of the weight of the whole conveyer belt  24 . 
     The openings  31  are formed by punching the top plate  21   b  from its surface side. This may form rounded surfaces at surface-side opening edges that slide along and contact the belt conveyer  24 , eliminating the need to chamfer these opening edges. 
     At lower positions on the outer surface of each side plate  21   a  of the conveyer frame  21  are disposed headed coupling pins  32  that are paired on the front and back sides of this frame. The coupling pins  32  are insertable and removable, from the upper side, in and out of engaging grooves  34  of coupling fittings  33  vertically mounted to outer side surfaces of the load measuring unit  6 . The conveyer frame  21  is inserted into between the coupling fittings  33 , and the coupling pins  32  are slightly forced into the engaging grooves. As a result, the weighing conveyer  3  is positionally fixed in front-back and right-left directions and securely fitted to the load measuring unit  6 . 
     This may cause the driven gear  25  of the driving roller  22  to mechanically mesh with the driving gear  26 , in response to which the weighing conveyer  3  can be driven to operate. By having the conveyer frame  21  pulled upward out of the coupling fittings  33 , the weighing conveyer  3  is separable from the weight measuring unit  6 , and interlocking with the driving gear  26  is automatically released. 
     At upper positions on the outer surface of each side plate  21   a  of the conveyer frame  21  are disposed headed coupling pins  35  that are paired on the front and back sides of this frame. The coupling pins  35  are insertable and removable, from the lower side, in and out of engaging grooves  36  of coupling sides  28   a  extending downward from lateral lower ends of the item-feeding guides  28 . The side plates  21   a  are pushed into between the coupling sides  28   a , and the coupling pins  35  are forced into the engaging grooves  36 . As a result, the item-feeding guides  28  are positionally fixed in front-back and right-left directions and securely fitted to the conveyer frame  21 . 
     According to this embodiment, the protective covers  8  for a plurality of weighing conveyers  3  arranged in rows have a long dimension in the direction of arrangement and are accordingly relatively heavy. These protective covers, however, need not be removed and readily open and close through simple rotations. These protective covers are rotated to and kept at the opening positions for maintenance like cleaning and are rotated back to the closing positions when the maintenance is over. Thus, maintenance including cleaning may be facilitated. 
     Unlike the known art, the control box is not disposed below the collection conveyer  2 , which leaves an unoccupied open space there. Any broken pieces or scraps of the items, if they fall out of the conveyers, may be likely to drop onto the floor surface. Thus, such broken pieces or scraps of the items and/or cleaning water may be unlikely to drop onto the upper surface of the control box and stay there, and the combination scale may be accordingly kept in a sanitary condition. 
     OTHER EMBODIMENTS 
     The scope of this invention may further include the following aspects. 
     1] The weighing conveyers  3  may be disposed on one side alone of the collection conveyer  2 .
 
2] The protective covers  8  may be rotatably supportable using a simple and typical hinge and may also be retainable at the closing positions using a self-lock mechanism. This instance, however, requires some kind of unlocking means to open the protective covers  8 .
 
3] In the earlier embodiment, side plates of the control box  7  are removable when the protective covers  8  are rotated to a large degree and kept at the opening positions. The protective covers  8  may be rotatable further downward and outward than described herein, in which case maintenance of the weighing conveyers  3  may be successfully performed without any interference of the protective covers  8 .
 
4] In case the combination scale has a greater number of weighing conveyers  3 , significantly increasing a region to be protected by the protective covers  8 , the protective covers  8  may be each divided in its longitudinal direction into two or more portions.
 
5] In the earlier embodiment, the protective covers  8  are rotated upward to close and rotated downward to open. In case a large working space is available around the combination scale, the protective covers  8  may be each structured to open and close through rotations around a longitudinal point of support at one end of the cover. In this instance, an operator may be able to more readily open and close the protective covers  8  without the need to bear the weights of these covers.
 
     REFERENCE SIGNS LIST 
     
         
           1  combination scale 
           2  collection conveyer 
           3  weighing conveyer 
           6  load measuring unit 
           7  control box 
           8  protective cover 
           9  hinge 
           10  display light 
         c interval