Patent Document

This application is a continuation of prior application No. 10/000,240, now U.S. Pat. No. 6,615,977, which is a continuation of prior application No. 09/837,917, now U.S. Pat. No. 6,321,895 which is a continuation of prior application No. 09,405,294, now U.S. Pat. No. 6,257,397. 
    
    
     TECHNICAL FIELD 
     The present invention generally relates to proofing and baking apparatus of the type utilized in large commercial bakeries, and more particularly to an improved conveyor for use in continuous proofing and baking apparatus which is characterized by extended service life and greater adaptability to the requirements of diverse baking operations. 
     BACKGROUND OF THE INVENTION 
     Modern large-scale commercial bakeries of the type utilized in the production of bread, sandwich buns, and similar dough products are frequently equipped with continuous proofing and baking apparatus. In the operation of a continuous proofer and/or oven, dough to be baked is received in bakery pans. The bakery pans are transported on grids which are supported on the links of a continuous chain. A drive mechanism actuates the chain to transport the bakery pans and the dough contained therein through a proofer wherein the dough is allowed to rise and/or through an oven wherein the dough is baked. 
     FIGS. 1,  2 , and  3  illustrate a link  20  of the type comprising a prior art conveyor chain utilized in continuous proofing and baking apparatus. Each link  20  of the conveyor chain includes a first connection member  22 , a second connection member  24 , and a pair of spaced, parallel plates  26 . The first connection member  22  of a particular link  20  is connected to the second connection member  24  of the next preceding link in the chain by a pin  28  (FIG. 3) which facilitates pivotal movement between adjacent links in the nominally vertical plane. The plates  26  are connected to the first connection member  22  and to the second connection member  24  by pins  30  which facilitate relative pivotal movement between adjacent links in the nominally horizontal plane. 
     The first connection member  22  of each link  20  is provided with a pair of wheels  32 . The wheels  32  support the link  20  for movement along a conveyor track  36  (FIG.  3 ). A wheel  34  is positioned between the plates  26 . The wheel  34  functions to center the link  20  in the conveyor track  36 . 
     Conveyor chains of the type illustrated in FIGS. 1-3 have gained widespread acceptance in the commercial baking industry and other industries. Notwithstanding this fact, such conveyor chains incorporate various deficiencies. For example, the wheels  32  which support each link  20  for moving along the conveyor track comprise anti-friction bearings which require periodic lubrication. Lubricating the chain is time consuming and expensive, and is frequently overlooked by bakery operators. Lack of lubrication leads to bearing failure which, at a minimum, requires the conveyor to be taken out of service to facilitate replacement of the failed bearings. As will be appreciated by those skilled in the art, substantially more serious consequences can and do result from bearing failure which can require the replacement of multiple links of the conveyor chain, entire sections of the conveyor track, etc. 
     Various factors lead to improper conveyor chain maintenance and lubrication. One of the most important involves the demands made on commercial bakeries by their customers for continuous high level production leaving no time for maintenance and lubrication procedures. An equally important factor is the lack of technicians having the training and experience necessary to properly perform conveyor chain maintenance and lubrication procedures. When untrained and inexperienced personnel are employed to maintain and lubricate the conveyor chains used in continuous proofers and ovens, improper and inadequate maintenance and lubrication result. 
     A related problem attendant to the use of conveyor chains comprising links of the type shown in FIGS. 1-3 relates to the cleaning thereof. The lubricants which are used in the anti-friction bearings of the wheels  32  of the links  20  are incompatible with the use of water and detergents to clean the conveyor chain. It is therefore necessary to employ other, more costly, techniques in order to attain the level of cleanliness required in food manufacturing operations. 
     Even when proper lubrication and cleaning procedures are in place, the problems inherent in the use of the prior art chain are not resolved. Lubricant from the chain combines with debris from the dough products being baked to form a sludge which cannot be disposed of except pursuant to strict EPA guidelines. When the chain is used in an oven the high temperature environment causes the lubricant to thicken to the point that the bearings seize causing increased load on the conveyor drive system and increased chain and track wear. 
     The design of the link  20  illustrated in FIGS. 1 and 2 also involves difficulties in changing the pitch of the conveyor chain incorporating the link, that is, the distance between identical points on adjacent links. The inability to easily change the pitch of the conveyor chain in turn means that the conveyor chain cannot be readily customized to specific load profiles, for example, lengthening the pitch for light load applications and reducing the pitch for heavy load applications. 
     Yet another problem involves the fact that the wheels  34  positioned between the plates  26  do not restrain the links of the chain from bending and tipping. When tipping occurs, the wheels  34  act as can openers cutting slits into the side walls of the conveyor track. Tipping also tilts the grids supported on the conveyor chain which can cause displacement of the bakery pans carried by the grids. 
     SUMMARY OF THE INVENTION 
     The present invention comprises improvements in the design of conveyor chains adapted for use in conveyorized proofers, conveyorized ovens, and similar applications which overcome the foregoing and other difficulties long since associated with the prior art. In accordance with one feature of the invention, conveyor chains intended for use in baking operations are provided with bearings which do not require lubrication. For example, when used in proofers, the bearings of the conveyor chain may comprise sleeve bearings formed from plastic materials which are self-lubricating and adapted for utilization in high temperature environments of the type encountered in a bakery oven. Conveyor chains used in ovens may be equipped with self-lubricating graphite bearings of the type sold by Graphite Metallizing Corporation of Yonkers, N.Y., under the trademark GRAPHALLOY®. Alternatively, the conveyor chain may be provided with sealed self-lubricating anti-friction bearings suitable for high temperature applications. 
     The use of bearings which do not require lubrication in conveyor chains intended for bakery applications is advantageous for at least two reasons. First, by eliminating the lubrication function which heretofore has proven to be problematical, substantial cost savings are effected. Of equal importance is the elimination of conveyor chain failures stemming from improper lubrication. The elimination of the lubrication requirement also facilitates the cleaning of the conveyor track by simply attaching a scraper to the conveyor chain. The scraper pushes bakery debris along the track to an opening in the bottom wall thereof where the debris is accumulated for disposal as ordinary refuse. 
     Those skilled in the art will understand that some types of self-lubricating bearings useful in the practice of the present invention may initially have a higher coefficient of friction as compared with the anti-friction bearings currently in use. Depending on the geometries of the components, a higher coefficient of friction can result in higher loads imposed on the conveyor drive system. However, the coefficient of friction of the currently used anti-friction bearings tends to increase over time, particularly in the absence of proper lubrication. Thus, the use of self-lubricating bearings is advantageous in that the loading of the conveyor drive system remains substantially constant throughout the life of the conveyor. 
     Another feature of the invention comprises the use of compact carriages to support the bakery pan receiving grids. Adjacent carriages are connected one to the other by connection members which can comprise either connection rods or connecting cables. The compact carriage/connection member design is advantageous in that it is readily adapted to changes in pitch, whereby the conveyor chain in the present invention can be easily customized to a range of conveyor loading situations. 
     In accordance with the preferred embodiment of the invention, the conveyor chain is comprised of a plurality of identical links having spaced apart pairs of vertically disposed and horizontally disposed wheels. The diameters of the wheels are closely matched to the interior dimensions of the track whereby the wheels prevent the chain from bending or twisting. Another important feature is the fact that the chain is economical to manufacture and assemble. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete understanding of the invention may be had by reference of the following Detailed Description when taken in conjunction with the accompanying Drawings, wherein: 
     FIG. 1 is an exploded perspective view of a link of a prior art conveyor chain; 
     FIG. 2 is a perspective view of the link of FIG. 1; 
     FIG. 3 is a top view of a conveyor chain comprising links of the type shown in FIGS. 1 and 2; 
     FIG. 4 is a side view of a conveyor chain comprising a first embodiment of the present invention in which certain parts have been broken away more clearly to illustrate certain features of the invention; 
     FIG. 5 is a view similar to FIG. 4 showing the conveyor chain of FIG. 4 operating in a vertically curved section of conveyor track; 
     FIG. 6 is a top view of the conveyor chain of FIG. 4 showing the conveyor chain operating in a horizontally curved section of conveyor track; 
     FIG. 7 is a transverse sectional view of the conveyor chain of FIG. 4; 
     FIG. 8 is an enlargement of a portion of FIG. 4; 
     FIG. 9 is an enlargement of a portion of FIG. 6; 
     FIG. 10 is a view similar to FIG. 4 showing a conveyor chain having a shorter pitch as compared with that of the conveyor chain of FIG. 4; 
     FIG. 11 is a side view similar to FIG. 4 showing a conveyor chain having a longer pitch as compared with that of the conveyor chain of FIG. 4; 
     FIG. 12 is a side view similar to FIG. 4 illustrating a conveyor chain comprising a second embodiment of the invention; 
     FIG. 13 is a side view similar to FIG. 4 illustrating a conveyor chain comprising a third embodiment of the invention; 
     FIG. 14 is a side view of a conveyor chain comprising a fourth and preferred embodiment of the invention in which certain parts have been broken away more clearly to illustrate certain features of the invention; 
     FIG. 15 is a side view of the conveyor chain of FIG. 14 showing the conveyor chain operating in a vertically curved section conveyor track; 
     FIG. 16 is a top view of the conveyor chain of FIG. 14 showing the conveyor chain operating in a horizontally curved section of conveyor track; 
     FIG. 17 is a transverse sectional view of the conveyor chain of FIG. 14; 
     FIG. 18 is an enlargement of a portion of FIG. 14; 
     FIG. 19 is a view similar to FIG. 14 illustrating a conveyor chain having a longer pitch as compared with that of the conveyor chain of FIG. 14; 
     FIG. 20 is a diagrammatic illustration of a conveyor chain drive mechanism useful in the practice of the invention; 
     FIG. 21 is a diagrammatic illustration of a conveyor chain drive mechanism comprising a variation of the conveyor chain drive mechanism of FIG. 20; 
     FIG. 22 is a diagrammatic illustration of the conveyor chain drive mechanism of FIG. 21 showing the utilization thereof in conjunction with a conveyor chain having a longer pitch as compared with that of the conveyor chain of FIG. 18; 
     FIG. 23 is an illustration similar to FIG. 18 showing a variation of the preferred embodiment of the invention; and 
     FIG. 24 is a diagrammatic illustration of a conveyor chain drive mechanism useful in conjunction with the apparatus of FIG.  23 . 
    
    
     DETAILED DESCRIPTION 
     Referring now to the Drawings, and particularly to FIGS. 4,  5 ,  6 ,  7 ,  8 , and  9  thereof, there is shown a conveyor chain  50  comprising a first embodiment of the invention. The conveyor chain  50  comprises a plurality of identical compact carriages  52  which are connected end to end by a plurality of identical connection members  54 . The conveyor chain  50  operates in a conveyor track  56  comprising a solid bottom wall  58 ; opposed, solid side walls  60 ; and a top wall  62  having a center slot  64  formed therein. 
     Each of the compact carriages  52  comprises a unitary structure which may be manufactured from a variety of materials utilizing conventional manufacturing techniques. For example, the compact carriages  52  may be manufactured from steel and/or other metals by means of die casting, investment casting, or other well known manufacturing processes. Alternatively, the compact carriages  52  may be formed from various plastic materials suitable for high temperature applications, and may be manufactured utilizing conventional processes such as injection molding. Preferably, the material and the process used in the manufacture of compact carriages  52  are selected such that few if any machining operations are required in order to complete the manufacture thereof. 
     Each compact carriage  52  comprises an elongate body  74  having identical openings  76  formed in the opposite ends thereof. Each opening  76  receives a spherical bushing  78  which in turn receives the end portion of one of the connection members  54 . The spherical bushings  78  are retained in the openings  76  by pins  80 . 
     Axles  82  extend through the body  74  at points situated inwardly from the opening  76 . The axles  82  support pairs of wheels  84  which in turn support the conveyor chain  50  for movement along the track  56 . Bosses  86  extend upwardly from the body  74  and in turn support a grid (not shown) which receives and transports bakery pans having dough received therein along the length of the track  56 . The bosses  86  may be provided with drilled and tapped apertures  88  which receive threaded fasteners to secure the grid thereto. Examples of grids which may be used in the practice of the invention are shown and described in U.S. Pat. Nos. 4,729,470, 4,760,911, and 4,836,360, all of which are owned by the assignee hereof and incorporated herein by reference. 
     Each of the bosses  86  may have a dimensionally reduced portion  90  at the upper end thereof. Top plates  92  are supported on the bosses  86  and receive the portions  90  therethrough. The top plates  92  function to prevent debris from entering the track  56  through the slot  64 . 
     Each compact carriage  52  is further provided with a pair of wheels  100 . The wheels  100  function to locate the compact carriage  52  relative to the side walls  60  of the track  56 . The wheels  100  are rotatably supported on a pin  102  extending through the body  74  of the compact carriage  52 . As is best shown in FIG. 7, the wheels  100  cooperate with the wheels  84  to completely prevent bending and tipping of the conveyor chain  50 . 
     Referring particularly to FIG. 9, the wheels  84  are secured to the axle  82  for rotation therewith. The axles  82  of conveyors intended for use in proofers may be supported by a self-lubricating plastic bearing  104  which may be of the type manufactured by Igus Spritzgussteile fur die Industrie GmbH (Igus) of Koln (Cologne), Germany and sold under the trademark IGLIDE®. In oven applications the self-lubricating bearings  104  may be of the type sold by Graphite Metallizing Corporation of Yonkers, N.Y., under the trademark GRAPHALLOY®. The bearings  104  do not require lubrication in order to rotatably support the axles  82  and the wheels  84  supported thereon. Therefore, by means of the present invention, the need for lubrication of the wheels which support the carriages  52  is eliminated as are the problems attended to the failure to provide required lubrication and difficulties associated with cleaning conveyor chains in which lubricating fluids are used. As is shown in FIG. 4, the wheels  84  may be rotatably supported by sealed self-lubricating anti-friction bearings  105  in lieu of the plastic bearings  104 . 
     Referring to FIG. 8, the wheels  100  are rotatably supported on the pin  102 . In conveyors used in proofers, self-lubricating plastic bearings  106  also manufactured by Igus are provided at the opposite ends of the pin  102  and in turn rotatably support the wheels  100  thereon. Conveyors for oven use may have bearings  106  of the type sold by Graphite Metallizing. Again, the use of self-lubricating bearings  106  to rotatably support the wheels  100  on the pin  102  eliminates the need for lubrication. 
     As is best shown in FIGS. 6 and 9, each connection member  54  has an eye  108  at each end thereof. Each eye  108  receives the spherical bushing  78  of one of the compact carriages  52 . In this manner, the eyes  108  of the connection members  54  and the spherical bushings  78  of the compact carriages  52  facilitate the movement of the conveyor chain  50  along inclined and curved portions of the track  56 . For example, FIG. 5 illustrates the movement of the conveyor chain  50  along a vertically curved portion  110  of the track  56 . FIG. 6 illustrates the movement of the conveyor chain  50  along a horizontally curved portion  112  of the track  56 . As will be appreciated by reference to FIGS. 5 and 6, the movement of the conveyor chain  50  along vertically and horizontally curved portions of the track  56  is accomplished without interference between the conveyor chain  50  and the track  56 . 
     FIG. 7 illustrates the relationship between the wheels  84  and  100  of the conveyor chain  50  and the track  56 . The wheels  84  travel along the bottom wall  58  of the track  56  and support the conveyor chain  50  of the movement through the track  56 . The wheels  100  serve to center the conveyor chain  50  in the track  56  and to prevent interference of the conveyor chain  50  with the track  56  as the conveyor chain  50  moves therethrough. Again, the wheels  84  and  100  cooperate to prevent bending and tipping of the conveyor chain  50 . 
     Referring to FIGS. 10 and 11, one of the advantages in the use of the conveyor chain in the present invention comprises the adaptability thereof to changes in pitch. Thus, in FIG. 10 the compact carriages  52  are connected end to end by connection members  54 ′ which are substantially shorter than the connection members  54  of the embodiment of the invention illustrated in FIGS. 4,  5 , and  6 . The use of the connection members  54 ′ in lieu of the connection members  54  results in a conveyor chain  50  having a substantially shorter pitch. The use of a conveyor chain having a shorter pitch is advantageous in those instances in which the conveyor chain is used to transport either heavier bakery pans or bakery pans carrying heavier loads as compared with the loading of a conveyor chain having a longer pitch. 
     Referring to FIG. 11, there is shown a conveyor chain  50  wherein the compact carriages  52  are connected end to end by connection members  54 ″ which are substantially longer than the connection members  54  of the conveyor chain  50  illustrated in FIGS. 4,  5 , and  6 . The use of the longer connection members  54 ″ in the conveyor chain  50  of FIG. 9 results in the conveyor chain having a substantially longer pitch as compared with the pitch of the conveyor chain  50  shown in FIGS. 4,  5 , and  6 . The use of a conveyor chain having a longer pitch is advantageous in those instances in which the conveyor chain is called upon to carry either lighter bakery pans or bakery pans carrying lighter loads as compared with the loading of the conveyor chain  50  of FIGS. 4,  5 , and  6 . 
     Referring to FIG. 12, there is shown a conveyor chain  150  comprising a second embodiment of the invention. The conveyor chain  150  comprises a plurality of identical compact carriages  152  which are connected end to end by a plurality of identical connection members  154 . The conveyor chain  150  operates in a conveyor track  156  comprising a solid bottom wall  158 ; opposed, solid side walls  160 ; and a top wall  162  having a center slot formed therein. 
     Each of the compact carriages  152  comprises a unitary structure which may be manufactured from a variety of materials utilizing conventional manufacturing techniques. For example, the compact carriages  152  may be manufactured from steel and/or other metals by means of die casting, investment casting, or other well known manufacturing processes. Alternatively, the compact carriages  152  may be formed from various plastic materials adapted for high temperature applications, and may be manufactured utilizing conventional processes such as injection molding. Preferably, the materials and the process used in the manufacture of compact carriages  152  are selected such that few if any machining operations are required in order to complete the manufacture thereof. 
     Each compact carriage  152  comprises an elongate body  174  having identical openings  176  formed in the opposite ends thereof. Each opening  176  receives a spherical bushing  178  which in turn receives the end portion of one of the connection members  154 . The spherical bushings  178  are retained in the openings  176  by pins  180 . 
     Axles  182  extend through the body  174  at points situated inwardly from the opening  176 . The axles  182  support pairs of wheels  184  which center the conveyor chain  150  in its movement along the track  156 . The axles are extended downwardly to prevent excess tipping of the compact carriages. A boss  186  extends upwardly from the body  174  and in turn support a grid (not shown) which receives and transports bakery pans having dough received therein along the length of the track  156 . The boss  186  may be provided with a drilled and tapped aperture  188  which receives a threaded fastener to secure the grid thereto. Examples of grids which may be used in the practice of the invention are shown and described in U.S. Pat. Nos. 4,729,470, 4,760,911, and 4,836,360, all of which are owned by the assignee hereof and incorporated herein by reference. 
     Each boss  186  may have a dimensionally reduced portion  190  at the upper end thereof. A top plate  192  is supported on each boss  186  and receives the portion  190  therethrough. The top plates function to prevent debris from entering the track  156  through the slot in the top wall  162 . 
     Each compact carriage  152  is further provided with a pair of wheels  200 . The wheels  200  function to support the compact carriage  152  for movement along the bottom wall  158  of the track  156 . The wheels  200  are rotatably supported on a pin  202  extending through the body  174  of the compact carriage  152 . 
     The wheels  184  are secured to the axle  182  for rotation therewith. Each axle  182  is rotatably supported by a self-lubricating bearing  204 . The bearings  204  do not require lubrication in order to rotatably support the axles  182  and the wheels  184  supported thereon. Therefore, by means of the present invention, the need for lubrication of the wheels which support the carriages  152  is eliminated as are the problems attendant to the failure to provide required lubrication and difficulties associated with cleaning conveyor chains in which lubricating fluids are used. 
     Like the rotational support for the wheels  184 , the wheels  200  are secured to the pin  202 . A self-lubricating bearing  206  rotatably supports the pin  202  and the wheels  200  mounted thereon. Again, the use of the self-lubricating bearings  206  to rotatably support the wheels  200  and the pin  202  eliminates the need for lubrication. 
     Each connection member  154  has an eye  208  at each end thereof. Each eye  208  receives a spherical bushing  178  of one of the compact carriages  152 . In this manner, the eyes  208  of the connection members  154  and the spherical bushings  178  of the compact carriages  152  facilitate the movement of the conveyor chain  150  along vertically and horizontally curved portions of the track  156 . 
     Referring to FIG. 13, there is shown a conveyor chain  250  comprising a third embodiment of the invention. The conveyor chain  250  comprises a plurality of identical compact carriages  252  which are connected at equally spaced intervals along a wire rope  254 . The conveyor chain  250  operates in a conveyor track  256  comprising a solid bottom wall  258 ; opposed, solid side walls  260 ; and a top wall  262  having a center slot formed therein. 
     Each of the compact carriages  252  comprises a unitary structure which may be manufactured from a variety of materials utilizing conventional manufacturing techniques. For example, the compact carriages  252  may be manufactured from steel and/or other metals by means of die casting, investment casting, or other well known manufacturing processes. Alternatively, the compact carriages  252  may be formed from various plastic materials suitable for high temperature applications, and may be manufactured utilizing conventional processes such as injection molding. Preferably, the material and the process used in the manufacture of compact carriages  252  are selected such that few if any machining operations are required in order to complete the manufacture thereof. 
     Each compact carriage  252  comprises an elongate body  274  having an opening  276  extending axially therethrough. The opening  276  receives the wire rope  254 . Compression sleeves  278  mounted on the wire rope  254  locate and secure each compact carriage  252  thereon. 
     Axles  282  extend outwardly from the body  274  at points situated inwardly from ends thereof. The axles  282  support pairs of wheels  284  which center conveyor chain  250  for moving along the track  256 . A boss  286  extends upwardly from the body  274  and in turn supports a grid (not shown) which receives and transports bakery pans having dough received therein along the length of the track  256 . The boss  286  may be provided with a drilled and tapped aperture which receives a threaded fastener to secure the grid thereto. Examples of grids which may be used in the practice of the invention are shown and described in U.S. Pat. Nos. 4,729,470, 4,760,911, and 4,836,360, all of which are owned by the assignee hereof and incorporated herein by reference. 
     The boss  286  may have a dimensionally reduced portion at the upper end thereof. A top plate may be supported on the boss  280  and receive the dimensionally reduced portion therethrough. If used, the top plates function to prevent debris from entering the track  256  through the slot in the top wall  262 . 
     Each compact carriage  252  is further provided with a pair of wheels  300 . The wheels  300  function to support the compact carriage  252  for movement along the bottom wall of the track  256 . The wheels  300  are rotatably supported on pins  302  extending from the body  274  of the compact carriage  252 . 
     The wheels  284  are each rotatably supported by a self-lubricating bearing. The self-lubricating bearings do not require lubrication in order to rotatably support the wheels  284 . Therefore, by means of the present invention, the need for lubrication of the wheels which support the carriages  252  is eliminated as are the problems attendant to the failure to provide required lubrication and difficulties associated with cleaning conveyor chains in which lubricating fluids are used. The wheels  300  are also rotatably supported by self-lubricating bearings. 
     Referring to FIGS. 14,  15 ,  16 ,  17 , and  18 , there is shown a conveyor chain  350  comprising a fourth and preferred embodiment of the invention. The conveyor chain  350  comprises a plurality of identical links  352  which are connected end to end to form the chain  350 . The conveyor chain  350  comprising the links  352  is adapted for movement along the length of a conveyor track  356  comprising a solid bottom wall  358 ; opposed, solid side walls  360 ; and a top wall  362  having a central slot formed therein. 
     Each component of the links  352  comprises a unitary structure which may be manufactured from a variety of materials utilizing conventional manufacturing techniques. For example, the links  352  may be manufactured from steel and/or other metals by means of die casting, investment casting, or other well known manufacturing processes. Alternatively, the links may be formed from various plastic materials adapted for high temperature applications, and may be manufactured utilizing conventional processes such as injection molding. Preferably, the material and the process used in the manufacture of links are selected such that few if any machining operations are required in order to complete the manufacture thereof. 
     Each link  352  comprises a first link portion  364  and a second link portion  366 . Each first link portion  364  is connected to its corresponding second link portion  366  by a pin  368  which facilitates relative pivotal movement between the link portions in the nominally vertical plane. Each pin  368  also has mounted thereon a pair of wheels  370  which support the link  352  for movement along the bottom wall  358  of the track  356 . 
     The second link portion  366  of each link  352  is connected to the first link portion  364  of the immediately following link  352  by a pin  372 . Thus, the pins  372  facilitate relative pivotal movement of the links  352  of the conveyor chain  350  in the nominally horizontal plane. Each pin  372  also supports two wheels  374  which serve to center the conveyor chain  350  and the track  356 . As is best shown in FIG. 17, the diameters of the wheels  370  and  374  are closely matched to the interior dimensions of the track  356  whereby the wheels  370  and  374  completely prevent bending or tipping of the chain  350 . 
     The pins  368  and  372  of the links  352  facilitate the movement of the conveyor chain  350  along inclined and curved portions of the track  356 . For example, FIG. 15 illustrates the movement of the conveyor chain  350  along a vertically curved portion of the track  356 . FIG. 16 illustrates the movement of the conveyor chain  350  along a horizontally curved portion of the track  356 . As will be appreciated by reference to FIGS. 15 and 16, the movement of the conveyor chain  350  along inclined and curved portions of the track  356  is accomplished without interference between the conveyor chain  350  and the track  356 . 
     Referring particularly to FIGS. 14,  16 ,  17 , and  18 , the wheels  370  are rotatably supported on the pins  368  by self-lubricating bearings  376 . Likewise, the wheels  374  are rotatably supported on the pins  372  by self-lubricating bearings  378 . The use of the self-lubricating bearings  376  and  378  to rotatably support the wheels  370  and  374 , respectively, eliminates the need for lubrication. As is shown in FIG. 14, the wheels  370  and  374  may be supported by sealed self-lubricating anti-friction bearings  379  adapted for high temperature applications in lieu of the bearings  376  and  378 . 
     Each first portion  364  of each link  352  includes a boss  380  extending upwardly therefrom and through the slot in the top wall  362  of the track  356 . Each boss  380  supports a grid (not shown) which receives and transports bakery pans having dough received therein along the length of the track  356 . Each boss  380  may be provided with a drilled and tapped aperture  382  which receives a threaded fastener to secure the grid thereto. Examples of grids which may be used in the practice of the invention are shown and described in U.S. Pat. Nos. 4,729,470, 4,760,911, and 4,836,360, all of which are owned by the assignee hereof and incorporated herein by reference. 
     Each boss  380  may have a dimensionally reduced portion  384  at the upper end thereof. Top plates  386  are supported on the bosses  380  and receive the portions  384  therethrough. The top plates function to prevent debris from entering the track  356  through the slot in the top wall  362  thereof. 
     Referring to FIG. 19, one of the advantages of the use of the conveyor chain in the present invention comprises the adaptability thereof to changes in pitch. Thus, in FIG. 19 there is shown a conveyor chain  350  having links  352 ′ which are substantially longer than the links  352  of the conveyor chain  350  illustrated in FIGS. 14,  15 , and  16 . The use of the longer links  352 ′ in the conveyor chain of FIG. 19 results in the conveyor chain having a substantially longer pitch as compared with the pitch of the conveyor chain  350  shown in FIGS. 14,  15 , and  16 . The use of a conveyor chain having a longer pitch is advantageous in those instances in which the conveyor chain is called upon to carry either lighter bakery pans or bakery pans carrying lighter loads as compared with the loading of the conveyor chain  350  of FIGS. 14,  15 , and  16 . 
     Referring now to FIG. 20, there is shown a drive mechanism  400  useful in conjunction with all of the conveyor chains illustrated in FIGS. 4 through 19, inclusive, and described hereinabove in conjunction therewith. The drive mechanism  400  includes a drive chain  402  which is trained around an idler sprocket  404 , an idler sprocket  406 , and a drive sprocket  407 . The drive sprocket  407  is actuated by a suitable drive mechanism to cause the drive chain  402  to move around the course defined by the sprockets  404  and  406 . 
     A plurality of chain engaging members  408  are supported on the drive chain  402  for engagement therewith. Each chain engaging member  408  includes a forward roller  410  which is rotatably supported on a pin  412  secured in the drive chain  402  and a rearward roller  414  which follows the surface of a cam  416  extending adjacent to the path of the drive chain  402 . 
     Referring particularly to the portion of the cam  416  extending adjacent to the idler sprocket  406 , if the rollers  410  and  414  were both secured to the drive chain  402 , the chain engaging members  408  would accelerate during movement around the idler sprocket  406 . However, utilizing the means of the engagement of the roller  414  with the cam  416 , each chain engaging member  408  remains parallel to its corresponding surface on the conveyor chain until the chain engaging member  408  has moved downwardly far enough to disengage from the conveyor chain. In this manner operating power is applied to the conveyor chain evenly and without periodic intervals of acceleration as would otherwise be the case. 
     FIG. 21 illustrates an alternative drive mechanism  420  which may be utilized in the practice of the invention. The drive mechanism  420  includes a drive chain  422  which extends around a course defined by a drive sprocket  424  and two idler sprockets  426  and  428 . 
     The drive mechanism further includes a plurality of conveyor chain engaging members  430  each dimensioned to fully fill the space between adjacent links of a conveyor chain. In this manner the drive mechanism  420  may be utilized to apply a breaking force to the conveyor chain. This is accomplished by slowly reducing the operating power that is supplied to the drive sprocket  424  or by completely reversing the direction of operation of the drive sprocket  424  depending upon the requirements of particular circumstances. 
     Each conveyor chain engaging member  430  is secured to the drive chain  422  by a pin. Each conveyor chain engaging member  430  is provided with a forward roller  434  and a rearward roller  436 . The rearward roller  436  follows a cam which is substantially identical in shape and function to the cam  416  illustrated in FIG.  20 . Thus, the rearward roller  436  causes the conveyor chain engaging member  430  to disengage from the conveyor chain without applying acceleration thereto. 
     The forward roller  434  of each conveyor chain engaging member  430  follows a track  438 . The movement of the forward roller  434  in the track  438  causes each conveyor chain engaging member  430  to enter into the space between adjacent links of the conveyor chain without applying either acceleration forces or deceleration forces thereto. Thus, the conveyor chain engaging member moves smoothly into the gap between adjacent links of the conveyor chain and into engagement with both of the adjacent links without applying forces thereto which otherwise would tend to change the speed of travel of the conveyor chain. 
     FIG. 22 illustrates the use of the drive mechanism  420  in those instances in which the pitch of the conveyor chain is too long for the conveyor engaging members  430  to fill the entire gap between adjacent links of the conveyor chain. In such instances a spacer  440  is mounted on each connection member of the conveyor chain at a suitable location between adjacent links thereof so as to receive the chain engaging member  430  between the spacer  440  and the link of the conveyor chain situated forwardly thereof. In this manner the drive mechanism  420  functions identically to the manner in which it functions as illustrated in FIG. 21 but without the necessity of employing conveyor engaging members which are unduly long. 
     Referring to FIGS. 23 and 24, there is shown a conveyor chain  450  comprising a variation of the conveyor chain  350  illustrated in FIGS. 14 through 18, inclusive, and described hereinabove in conjunction therewith. The conveyor chain  450  is identical to the conveyor chain  350  except that it comprises identical links  352 ′ each having upper and lower drive cams  452  and  454  secured thereto by fasteners  456 . 
     FIG. 24 illustrates a drive mechanism  460  useful in conjunction with the conveyor chain  450 . The drive mechanism  460  includes a drive motor  462  which actuates a drive sprocket  464 . A drive chain  466  is trained around the drive sprocket  464  and two idler sprockets  468  and  470 . 
     A drive chain cam  472  extends between the idler sprockets  468  and  470 . The drive chain  466  carries a plurality of drive forks  476 . Upon actuation by the drive motor  462 , the drive sprocket  464  actuates the drive chain  466  to move the drive forks  476  around a course extending from the drive sprocket  464  around the idler sprocket  468 , across the drive chain cam  472 , around the idler sprocket  470 , and back to the drive sprocket  464 . 
     As each drive fork  476  moves into engagement with the drive chain cam  472  it is gradually lifted into engagement with one of the drive cams  452  on one of the links  352 ′ of the conveyor chain  450 , being understood that an identical drive fork engages the drive cam  454  on the opposite side of the particular link  352 ′. As will be appreciated by those skilled in the art, the drive chain  466  and the conveyor chain  450  move at the same speed. Therefore, the drive forks of the drive chain  466  engage the drive cams of the conveyor chain  450  without applying any acceleration force or any deceleration to the conveyor chain  450 . Subsequently, the drive chain cam  472  gradually lowers each drive fork  476  out of engagement with the drive cam  452  with which it has been engaged. Again, the disengagement between the drive forks and the drive cams is accomplished without applying any acceleration force or deceleration force to the conveyor chain  450 . 
     Although preferred embodiments of the invention have been illustrated in the accompanying Drawings and described in the foregoing Detailed Description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions of parts and elements without departing from the spirit of the invention.

Technology Category: b