Abstract:
A belt module suitable for use in a modular belt and designed for holding attachments such as flights. The belt module has an attachment holder with a dovetail section on the upper surface that accommodates attachments and the like that are designed to be removably attached to the holder by means of attachments furnished with foot extensions that fit into the dovetail section by sliding the foot laterally into a locked position relative to the attachment holder.

Description:
FIELD OF THE INVENTION 
   This invention relates to conveyor belts and, more particularly, to modular plastic conveyor belts formed of rows of plastic belt modules pivotally interlinked by transverse pivot rods. 
   BACKGROUND OF THE INVENTION 
   Modular belts may be furnished with accessories such as flights that may be produced integrally on special flight modules that are connected to standard modules. The flight modules may be connected in rows of single modules as part of a chain or the flight modules may be connected to adjacent rows of modules in a bricklayed fashion. In order to provide greater flexibility for using various types of attachments on the same belt type or for easier repair, it is known to provide specially designed modules with removable accessories. An example of this type of module is shown in U.S. Pat. No. 4,832,183. This design includes a recess within the intermediate section between the links of the belt module such that an accessory (i.e., flight) can be shifted into locking position from the side of the module. Installation or removal of the attachments disclosed in the &#39;183 patent requires space on the side of the belt. This space has to be as wide as the flight itself. If the free side movement is obstructed or belts are running side-by-side, the space for side clearance is not available and installation or removal of the accessory is only possible after the belt has been uninstalled. Such typical applications include vertical pan conveyors in bakeries as schematically shown in  FIGS. 1A and 1B . Special belts  10  having a plurality of flights  12  are running side-by-side to carry pans  13  and to move them vertically in the direction of arrow  16 . The pans  13  are used to convey baked goods  14 .  FIGS. 1A and 1B  show one pair of belts  10  only. The belts  10  articulate about sprockets  17  in the direction of arrows  18 ,  19 . In the actual application a series of belts are running side-by-side in such a way that a series of pans, which move with the belts from bottom to top, are carried in a large enclosure. 
   U.S. Pat. No. 6,554,129 discloses snapped on flights, but the system is not safe enough in all applications because it may disengage at high load. For vertical pan conveyors in bakeries as discussed previously, special requirements have to be fulfilled. The loads are usually quite high and the attachments need to be well secured to the belt. In this application, the pans may become jammed and the attachments may be damaged and need to be replaced. Also, the accessory or belt may break completely. In such a case it is desirable to assure that only the removable attachment is damaged and not the belt. 
   Accordingly, there is a need for removable attachments that allow for secure attachment in a flexible manner. The system should provide for positive fixation of the attachment allowing high loads without risk of disengagement. The system should not require significant side clearance. Also, the system should provide optional disengagement on breakage of the attachment at a calculated limit to protect the belt from damage due to overload. 
   SUMMARY OF THE INVENTION 
   The present invention meets the above-described need by providing a module for holding an attachment. The module has an intermediate portion with an upper surface having at least one pair of opposed dovetail sections extending above the upper surface. The dovetail sections are disposed in spaced-apart relation from the side edge of the module. The module has a first plurality of link ends that extend outward from the intermediate portion. The first plurality of link ends have transverse openings defined therein. A second plurality of link ends extend outwardly from the intermediate portion in a direction opposite to the first plurality of link ends. The second plurality of link ends are offset from the first plurality of link ends such that the first plurality of link ends are capable of intercalating with the second plurality of link ends of an adjacent module. The second plurality of link ends also have transverse pivot rod openings defined therein. When the first and second link ends of adjacent modules are intercalated, a transverse pivot rod can be inserted to pivotally connect adjacent rows of modules to form an endless belt capable of articulating about a sprocket. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is illustrated in the drawings in which like reference characters designate the same or similar parts throughout the figures of which: 
       FIG. 1A  is a schematic diagram of a vertical conveyor; 
       FIG. 1B  is a front elevational view of the conveyor of  FIG. 1A ; 
       FIG. 2A  is perspective view of a belt with a flight attachment according to the present invention; 
       FIG. 2B  is a perspective view of the belt of  FIG. 2A  with an alternate embodiment of the flight attachment; 
       FIG. 3A  is a perspective view of the belt of the present invention with the attachment removed to illustrate individual belt modules having one attachment holder per module; 
       FIG. 3B  is a perspective view of an alternate embodiment with two attachment holders per module; 
       FIG. 4A  is an enlarged perspective view of a module having a single attachment holder; 
       FIG. 4B  is an enlarged plan view of a module having two attachment holders disposed thereon; 
       FIG. 5A  is a perspective view of a flight attachment of the present invention; 
       FIG. 5B  is a perspective view of an alternate embodiment of the flight attachment; 
       FIG. 5C  is an enlarged perspective view of a portion of the attachment of the present invention; 
       FIG. 6A  is a perspective view showing engagement of the attachment with the attachment holders; 
       FIG. 6B  is an enlarged perspective view showing a portion of the attachment in relation to an attachment holder; 
       FIG. 6C  is a perspective view of a portion of the attachment showing the flight attachment engaged with an attachment holder of the present invention; 
       FIG. 6D  is an end view of the flight attachment engaged with the attachment holder; 
       FIG. 7A  is a perspective view of a belt with a flight attachment affixed thereto according to the present invention; 
       FIG. 7B  is a perspective view of the belt of  FIG. 7A  with the flight attachment removed; 
       FIG. 8A  is an enlarged perspective view of the alternate embodiment of the flight attachment attached to a module with an attachment holder; and, 
       FIG. 8B  is a perspective view of the alternate embodiment of the flight attachment. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In  FIG. 2A , a modular belt  20  has a plurality of belt modules  23  that are pivotally connected by a pivot rod  26  through aligned transverse pivot rod openings  29  as will be evident to those of ordinary skill in the art based on this disclosure. The belt  20  may be used for a vertical pan conveyor moving in the direction of arrow  21 . The belt modules  23  are flush grid type with openings  24  disposed from the top surface through to the bottom surface. The present invention may also be utilized with other types of modules including, but not limited to, closed, flat top modules. Each of the modules  23  has a first plurality of link ends  32  extending from one side and a second plurality of link ends  35  extending from the opposite side. 
   The belt  20  is provided with a specially designed module  30  ( FIGS. 3A ,  3 B) having an attachment holder  100  for fixing an attachment such as a flight  37  to the belt  20 . The attachment may be produced from rigid plastic materials such as polypropylene, polyethylene, polyacetal, polyamide or the like. Also, the attachment may be produced from elastic materials such as a thermoplastic rubber-like material or the like. As shown in  FIG. 2A , the flight  37  has a straight upstanding wall  40  extending from a base portion  41 . The flight  37  may include tapered end portions  43  and  46 . As an alternative shown in  FIG. 2B , a flight  49  having a wall  50  may also be used. The wall  50  extends from a base portion  51 . The wall  50  is corrugated in shape, and may also include a pair of tapered sections  52 ,  55 . The corrugated flight  49  may provide some advantages for a strong and stiff design that is easily cleanable and easy to mold because of the constant wall thickness. Other types of attachments such as buckets, bent flights, elastic flights, perforated flights, or the like are also possible. 
   Turning to  FIG. 3A , belt  20  includes modules  30  with attachment holders  100 . As shown there are four modules  30  with attachment holders  100  inserted within a row  21  of belt modules. Each attachment holder  100  has a midportion  103  with surface  106  for supporting the flights. A pair of dovetail sections  109 ,  112  are disposed opposite from each other and in spaced apart relation from the surface  106 . The modules  30  have spaced apart link ends  115 ,  118  extending from opposite sides in the direction of belt travel for intercalating with the link ends  32  and  35  of the adjacent modules  23 . The link ends  115 ,  118  have transverse openings  121  ( FIG. 4A ) that align with the transverse openings  124  in the intercalated link ends  32 ,  35 . With the transverse openings  121 ,  124  aligned, the modules  30  are connected to the adjacent modules  23  by inserting a transverse pivot rod  133  as will be evident to those of ordinary skill in the art based on this disclosure. As shown in  FIG. 3A , the surface  106  has a width W 1  that is visible on the right hand side of the modules  30  in the figure. Towards the middle of the modules  30 , the dovetail sections  109 ,  112  have end walls  136  that form a narrower opening W 2  exposing a portion of the surface  106 . A rib  120  is disposed on the surface  106  toward the left hand side of the attachment holder  100 . The rib  120  provides a structure for retention of the flight attachment as described in greater detail below. Additional structure of the holder  100  and details of the engagement with the flight attachment are described in greater detail below. 
   In  FIG. 3B , an alternate embodiment of the module  30  with holders  100  is shown. Module  230  includes attachment holder  150  which may include four dovetail sections  153 ,  156 ,  159 , and  162 . The belt  20  is shown with two modules  230  with attachment holders  150  comprising one row  21  of belt  229 . 
   Referring to  FIG. 4A , module  30  with attachment holder  100  is shown in greater detail. The dovetail sections  109 ,  112  extend above and substantially parallel to surface  106  of the module  30 . The dovetail sections  109 ,  112  form a slot having a width W 2  that is smaller than the width W 1  of the mid portion  113  of the module  30 . The midportion  113  may be recessed to form a groove  114  bordered by surface  106  and side walls  107 . The surface  106  and the dovetail sections  109 ,  112  form a T-shaped opening that extends to the rib  120  and to the end walls  201 ,  202  extending underneath the dovetail sections  109 ,  112 . 
   In  FIG. 4B , module  230  with attachment holder  150  is shown. The dovetail sections  153 ,  156  are separated from dovetail sections  159 ,  162  by a distance a. The space a between the dovetail sections may be provided by adjacent modules  30  as shown in  FIG. 4A  or it may be provided integrally within a single module  230  as shown in  FIG. 4B . In either arrangement the opening a provides space for installing the attachments as will be described in greater detail herein. 
   Turning to  FIGS. 5A-5C , flight  37  is provided with feet  250  that extend from the bottom surface  253  of the flight  37 . The feet  250  (as shown in  FIG. 5C  in connection with corrugated flight  49 ) may be attached to a rail-shaped portion  256  at the bottom of the flight. The feet  250  have a width b and are wider than the rail-shaped portion  256 . The feet  250  have a square or rectangular shape with side walls  265 ,  268 . The bottom surface  271  of the foot  250  extends substantially parallel to the bottom surface  253  of the flight  49 . At the front of one of the feet  250 , there is a locking member  275 . The locking member  275  has a cantilevered section  278  extending to a distally positioned latch portion  281 . The cantilevered portion  278  is capable of deflecting so that the latch portion  281  may pass over the rib  120  and then snap down beyond it to lock the attachment into position in the attachment holder. 
   Turning to  FIGS. 6A and 6B , the installation of an attachment is shown. In  FIG. 6A , four modules  30  with attachment holders  100  are aligned in a single row with link ends  118  disposed in transverse alignment for pivotal connection with adjacent modules. The modules  30  are disposed adjacent to one another along an end wall  284 . The arrangement creates a gap A for receiving the foot  250 . As shown in  FIG. 6B , a slot for receiving foot  250  is created by surface  106  of module  30 , side wall  107 , and dovetail section  109 . The slot is bordered at the end by rib  120  as shown. The other side of the attachment holder  100  is identically formed with dovetail section  112 , the opposite sidewall  107 , and surface  106 . 
   Turning to  FIG. 6C , the attachment is installed by sliding the foot  250  in the slot described above until the latch portion  281  slides over the rib  120  (in the direction from right to left with respect to the orientation of the figure) and locks into the position shown such that the attachment cannot be slid in the reverse direction in the slot without releasing the latch portion  281  from the rib  120 . 
   In  FIG. 6D , the latch portion  281  is engaged with the rib portion  120 . The module  30  is connected to the adjacent module  23  by means of a transverse pivot rod  133  disposed in the aligned transverse pivot rod openings  121 ,  124 . The rail portion  256  extends between the dovetail sections  109 ,  112  and the foot  250  fits in the spaces created underneath the dovetail sections  109 ,  112 . The foot portion  250  is blocked by the rib  120  in  FIG. 6D  and therefore not visible. 
   Turning to  FIGS. 7A and 7B , a belt  300  according to the present invention includes standard modules  23  which are shown as flush grid modules. The attachment is a flight  37  with upstanding wall  40  extending to tapered end portions  43  and  46 . The flight  37  extends from a first side edge  303  of the belt  300  to the opposite side edge  306 . However, the belt  300  has standard modules  23  at the sides near the edges  303 ,  306 . In  FIG. 7B , the belt  300  is shown with the flight  37  removed. A pair of modules  230  with attachment holders  150  are connected in the center of the belt  300 . Standard modules  23  are disposed at the side edges  303 ,  306  of the belt. 
   Turning to  FIGS. 8A and 8B , an alternate embodiment of the invention with a shorter attachment  400  is shown. The belt  403  has side edges  406  and  409 . The shorter attachments  400  can be connected to attachment holders  100  on individual modules  30 . The individual modules  30  can be alternated with normal modules  23  within the same row  405  as shown. 
   The present invention provides many advantages including flexibility in applications where side clearance is limited. The side movement needed for each flight corresponds to the foot width b and can be designed to be very short (i.e. 30 mm). 
   The present invention also provides for using modules  30  with single attachment holders  100  assembled in a row side-by-side. The number of attachment holders  100  depends on the length of the attachments. The splitting of the attachment holder into short sections has particular advantages: short modules are more flexible and versatile because they can be used for different attachment lengths; if a predetermined fixing strength is desired in order to allow the attachment to disengage at a certain load without damaging the belt it is possible to reduce the number of attachment holders; and, short modules may be combined with normal modules in between and at the belt edges. 
   In order to provide attachments that release without belt damage, the attachment holders may be designed to hold the attachments up to a certain force limit such that if the limit is exceeded, the holder will flexibly open to release the flight without damage. This fail safe design feature may be accomplished in various ways. The dovetail section may be formed from material that is flexible enough to release the attachment. Other devices such as springs or the like could also be used. Once the remaining broken part is removed it can be replaced by a new flight attachment. Another possibility is to dimension the upstanding wall of the flight attachment such that it will break near the attachment holder at a predetermined load. 
   While the invention has been described in connection with certain embodiments, it is not intended to limit the scope of the invention to the particular forms set forth, but, on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.