Patent Publication Number: US-2023152146-A1

Title: Conveyer and combination scale equipped with the same

Description:
TECHNICAL FIELD 
     This invention relates to a conveyer for transport and a combination scale equipped with the conveyer. 
     BACKGROUND ART 
     Patent Literature 1 describes an example of conveyers for transport which is equipped with a conveyer belt, a driving roller, a driven roller, a conveyer belt wound around the driving and driven rollers, and a pedestal pivotally supporting these rollers. This conveyer is further characterized in that an inner peripheral surface of the conveyer belt slides along and contacts an upper peripheral surface of the pedestal. 
     CITATION LIST 
     Patent Document 
     
         
         Patent Document 1: JP 1999-343018 A 
       
    
     SUMMARY OF THE INVENTION 
     Technical Problems 
     In the conveyer described in Patent Literature 1, there is a large area of contact between the conveyer belt and the upper surface of the pedestal including a top plate. This may accelerate abrasion of the conveyer belt and may also invite a greater sliding resistance, leading to a greater driving load. Some weighing conveyers are for use in transport of foodstuffs, and such weighing conveyers are cleaned relatively often. Cleaning water used then may leave droplets between the conveyer belt and the upper surface of the pedestal. Such water droplets may be likely to form a membrane in portions where sliding contact occurs, and surface tension of the water membrane may often disturb smooth operation of the conveyer belt. 
     The transport conveyers are desirably smaller in weight for easy handling during the cleaning, and conveyers for use in weighing purpose, in particular, are more desirably lightweight. Weight sensors smaller in capacity may be usable in such lighter weighing conveyers with smaller tare weights. This may achieve an improved resolution and a resulting higher weighing accuracy. 
     This invention was accomplished to address these issues of the known art and is directed to providing a transport conveyer reducible in weight and allowed to minimize abrasion of a conveyer belt, and a combination scale equipped with the transport conveyer. 
     Technical Solution 
     To this end, this invention provides the following technical aspects. 
     1] A transport conveyer according to this invention includes: 
     a driving roller disposed on one side in a direction of transport; 
     a driven roller disposed on another side in the direction of transport; 
     a conveyer frame to which the driving roller and the driven roller are mountable; and 
     a conveyer belt wound around the driving roller and the driven roller. 
     The transport conveyer is further characterized in that the conveyer frame includes: 
     a pair of side plates that axially supports both ends of the driving roller and of the driven roller; and 
     a top plate that slides along and contacts an inner peripheral surface of the conveyer belt, and 
     the top plate has a plurality of openings. 
     In the transport conveyer according to this invention, the openings formed in the top plate may allow the conveyer frame to reduce in weight and may also lead to a smaller area of contact between the inner peripheral surface of the conveyer belt and the top plate of the conveyer frame. Such a smaller area of contact may lead to less abrasion of the conveyer belt and a smaller sliding resistance, further leading to a smaller belt driving load. Further advantageously, the sliding resistance caused by droplets of cleaning water may be less variable, achieving a smooth belt operation. 
     2] In a preferred embodiment of this invention, the pair of side plates and the top plate are integrally formed by bending. 
     According to this embodiment, the side plates and the top plate are formed as an integral unit. This may conduce to cost reduction as compared with the side plates and the top plate being independently produced from different materials. 
     3] In other embodiments of this invention, the top plate has a groove formed by bending, the groove extending along an entire length thereof in the direction of transport at an intermediate position in a direction orthogonal to the direction of transport. 
     According to these embodiments, the formation of this groove by bending may simply decrease the area of contact between the tope plate and the conveyer belt and may also improve the top plate in rigidity. This may allow a thinner material to be used for the conveyer frame, conducing to weight reduction of the conveyer frame. 
     In other embodiments of this invention, one of the pair of side plates of the conveyer frame has a gear housing integrally formed at one end on a driver side thereof, the gear housing serving to house a gear disposed at one end of the driving roller. 
     According to these embodiments, an additional working process becomes unnecessary to form and attach an independent gear housing, leading to cost reduction. 
     5] 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; and a collection conveyer that transports the items discharged from the weighing conveyers along a direction of arrangement of the weighing conveyers, the transport conveyer recited in one of 1] to 4] constituting each of the weighing conveyers. 
     The combination scale according to this invention may achieve the following advantages: successful control of abrasion of the conveyer belt, reducing the number of belt replacements; easy and speedy removal for cleaning of the lighter and easily handleable weighing conveyers, facilitating maintenance; and the lighter weighing conveyers leading to use of weight sensors smaller in capacity and improved in resolution, achieving a higher weighing accuracy. 
     Effects of the Invention 
     As described thus far, this invention may successfully provide a transport conveyer reducible in weight and allowed to control abrasion of a conveyer belt, and a combination scale equipped with the transport conveyer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a combination scale equipped with a transport conveyer 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 in which weighing conveyers have been removed from load measuring units. 
         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  1 .  FIG.  3    is a front view of the combination scale  1 . 
     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 of 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 ; a conveyer unit including transport conveyers according to an embodiment of this invention, 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 into the packaging machine. 
     For clear and easy understanding of what is described herein, the following directions are hereinafter defined; “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 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  of the weighing conveyers  3  may offer a large working area for maintenance and cleaning of the collection conveyer  2 . 
     Protective covers  8 , which are laterally long, 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 driver 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. 
     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 the driving motor is 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 formed by press working of metallic, plate-shaped materials, for example, stainless steel. These side and top plates are integrally formed by bending the plate-shaped materials. This may conduce to cost reduction as compared with the side plates and the top plate being independently produced from different materials. 
     The driving roller  22  is pivotally supported in a freely rotatable manner by the side plates  21   a  at one end (rear end) of the conveyer frame  21 . 
     On the sides plates  21   a  at the other end (front end) of the conveyer frame  21 , bearing brackets  27  are coupled with bolts  19  to both ends of a coupling shaft  18  interposed between the side plats  21   a . The tension roller  23  is pivotally supported by these bearing brackets  27  in a freely rotatable manner. The tension roller  23  is also slidably and elastically biased outward by spring-embedded tension mechanisms  29 . 
     The bearing brackets  27  each have, at its front end, an engaging hole  27   b . Both ends of a support shaft  23   a  of the tension roller  23  are inserted through the engaging holes  27   b . The support shaft  23   a  is supported in a non-rotatable manner at front ends of the tension mechanisms  29  attached to the bearing brackets  27 . The support shaft  23   a  is also elastically biased forward by the springs embedded in the tension mechanisms  29 . These structural features constitute an automatic tension mechanism that strains forward the conveyer belt  24  wound around the tension roller  23 . 
     The weighing conveyers  3  are removed from the load measuring units  6 , and item-feeding guides  28  described later are then removed. Then, the bearing brackets  27  are rotated upward around the bolt-attached coupling shaft  18 , as illustrated with a virtual line in  FIG.  10   . When the bearing brackets  27  are rotated upward, the conveyer belt  24  is loosened and easily removable from a lateral side of the conveyer frame  21 . 
     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 brackets  27  in a manner that the support shaft is slidable back and forth but is not rotatable. 
     A gear housing  21   c , in which the driven gear  25  of the driving roller  22  is containable, 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 gear housing  21   c  thus integral with one of the side plates  21   a  makes a process to attach an independent gear housing unnecessary, leading to cost reduction. Further advantageously, the formation of the gear housing  21   c  by bending may improve the side plates  21   a  in rigidity. 
     The top plate  21   b  of the conveyer frame  21  slides along and contacts, from the lower side, an inner peripheral surface of the conveyer belt  24  would around the rollers. The top plate  21   b  has a groove  30  formed along its entire length at a laterally middle position. This groove  30  has a rectangular shape in cross section having both sides bending downward at substantially the right angle and lower ends on these both sides bending laterally at substantially the right angle. This groove has a width of more than ⅓ of the width of the top plate  21   b . The groove  20  thus formed by bending may serve as a rib, improving the whole conveyer frame  21  in rigidity. This may allow the conveyer frame  21  to reduce in thickness and weight. 
     Further advantageously, this groove  30  may serve to avoid any interference with a guiding projection  24   a  illustrated in  FIGS.  11  and  12   . This guiding projection  24   a  is formed on the inner peripheral surface of the conveyer belt  24  to prevent meandering movements. 
     The guiding projection  24   a  on the inner peripheral surface of the conveyer belt  24  is engaged with guiding grooves  22   a  and  23   a  formed in the outer peripheral surfaces of the diving roller  22  and of the tension roller  23 , as illustrated in  FIG.  11   . This may prevent the rotating conveyer belt  24  from meandering in the lateral direction. 
     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 , as illustrated in  FIGS.  11  and  13   . 
     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 weight of the whole conveyer belt  24 , and reduction of the area of contact of the top plate  21   b  with the conveyer belt  24 , leading to less sliding resistance. Further, the staggered formation of these openings  31  may effectively prevent the top plate  21   b  from degrading in strength. 
     The openings  31  are formed by punching the top plate  21   b  from its surface side, and surface-side edges of these openings may accordingly have rounded surfaces and need not be chamfered. 
     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  mounted vertically 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  34 . 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 . 
     As a result of the weighing conveyer  3  being thus secured, the driven gear  25  of the driving roller  22  may be mechanically meshed with the driving gear  26 , in response to which the weighing conveyer  3  is 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 load measuring unit  6 , and interlocking with the driving gear  26  is automatically released. 
     The conveyer frame  21  of the weighing conveyer  3  may be thus positionally fixed in the vertical direction and engaged with the load measuring unit  6 . The conveyer frame  21 , for such an event as cleaning, may be readily and speedily removed from and attached to the load measuring unit  6  of the weighing conveyer  3 . 
     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 formation of the openings  31  in the top plate  21   b  of the conveyer frame  21  decreases the area of contact of the top plate  21   b  with the inner peripheral surface of the conveyer belt  24 . This may reduce the risk of abrasion of the conveyer belt  24  and may also reduce the sliding resistance, leading to a smaller belt driving load. Further advantageously, variability of the sliding resistance caused by droplets of cleaning water may also reduce, allowing a smooth belt operation. 
     This embodiment may achieve the following advantages: successful control of abrasion of the conveyer belt  24 , reducing the number of belt replacements; easy and speedy removal for cleaning of the lighter and easily handleable weighing conveyers  3 , facilitating maintenance; and the lighter weighing conveyers  3  leading to use of weight sensors smaller in capacity and improved in resolution, achieving a higher weighing accuracy. 
     OTHER EMBODIMENTS 
     The scope of this invention may further include the following aspects. 
     1] The openings  31  formed in the top plate  21   b  of the conveyer frame  21  each have a circular shape in the earlier embodiment. Instead, the openings  31  may have other optional shapes, for example, elliptical shape or slit-like shape elongated in the direction of transport. Regardless of any optional shape of the openings, the staggered arrangement may likewise reduce the risk of strength degradation.
 
2] In the earlier embodiment, the transport conveyer according to this invention is applied to the weighing conveyer of the semi-automatic combination scale  1 . This invention is also applicable to general-purpose transport conveyers simply configured to carry and transport items.
 
     REFERENCE SIGNS LIST 
     
         
           1  combination scale 
           2  collection conveyer 
           3  weighing conveyer (transport conveyer) 
           21  conveyer frame 
           21   a  side plate 
           21   b  top plate 
           22  driving roller 
           23  tension roller (driven roller) 
           24  conveyer belt 
           24   a  guiding projection 
           28  item-feeding guide 
           30  groove 
           31  opening