Abstract:
A multi-level conveyer mainly includes a plurality of carrier units connected at front and rear ends to two parallelly extended chains, and chain wheels provided at predetermined positions for the chains to pass there and turn to form more than one level of horizontal conveyance path on the conveyer. The multi-level conveyer can be mounted in a room with limited area while providing sufficient conveyance length and time to meet requirements in most drying operations and largely reduce power consumption required in drying.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a multi-level conveyer that requires only limited space while providing increased conveyance length and time, such that articles conveyed on the conveyer can be sufficiently dried during conveyance. 
     It is known that most pulp-molded articles and baking-finished products must be dried during their manufacturing process. Particularly, the pulp-molded articles require sufficiently long drying to complete the production thereof. Articles or products having larger volume would require longer time of drying. To sufficiently dry articles or products, it necessitates a drying room with sufficient area and a surface conveyer with sufficient conveyance length, so that articles or products on the conveyer could be dried for a long enough time and fully meet the required dryness when they are removed from the conveyer. 
     For a surface conveyer, both the structural design thereof and the area of drying room for accommodating the conveyer limit the conveyance length available on the conveyer. Following are some disadvantages of the surface conveyer: 
     1. The drying room for accommodating the surface conveyer must be considerably large in area: 
     To successfully perform the drying, the surface conveyer must be able to provide a long conveyance path and therefore requires large drying room to accommodate the long conveyer, and costs for such large drying room will be inevitably high. 
     2. Higher power consumption is required for the surface conveyer in a large drying room: 
     With a large drying room, higher power must be consumed for the whole drying room to reach a minimum working temperature to perform the drying well. 
     It is therefore tried by the inventor to develop a multi-level conveyer to eliminate drawbacks existing in the conventional surface conveyer. 
     SUMMARY OF THE INVENTION 
     A primary object of the present invention is to provide a multi-level conveyer that can be mounted in a limited space while provides conveyance length long enough for sufficient drying operation with reduced power consumption. 
     The multi-level conveyer according to the present invention includes a plurality of serially arranged carrier units, front and rear ends of which being connected to two parallelly extended chains. Chain wheels are provided at predetermined positions in the conveyer. When the chains pass the chain wheels, they turn by  90  degrees to move into a higher or a lower level of the conveyer. The carrier units are conveyed from a bottom level of the conveyer to a top level and then moved downward to sequentially pass every lower levels and the bottom level to complete one cycle of conveyance on the conveyer. 
     In the multi-level conveyer of the present invention, the carrier unit is disposed between the two parallel chains by separately connecting two ends of a central pivotal shaft of the carrier unit to the two chains, such that when the carrier unit is moved by the chains to pass any chain wheel and turns, the central pivotal shaft revolves relative to the carrier unit to keep the latter in a horizontal position. 
     Retainer walls are provided in the multi-level conveyer of the present invention at outer side of every turns and vertical conveyance paths to contact with outer sides of the carrier units passing the turns or the vertical paths, preventing the carrier units from rotating at the turns due to an inertia force or tilting at the vertical paths. 
     The carrier units of the present invention are provided at two lateral sides near two ends thereof with a pulley support each. The pulley support each includes a vertical bar having two pulleys mounted to upper and lower ends thereof. The pulleys rotatably contact with the retainer walls when the carrier unit passes a turn or a vertical path and therefore reduce friction between the carrier unit and the retainer wall. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein 
     FIG. 1 is an elevation of a multi-level conveyer according to a preferred embodiment of the present invention; 
     FIG. 2 is a fragmentary and enlarged perspective of a carrier unit of the multi-level conveyer of the present invention; 
     FIG. 3 is a front elevation of the carrier unit of FIG. 2; 
     FIG. 4 is a sectional view of the carrier unit taken on line  4 — 4  of FIG. 3; and 
     FIG. 5 is a fragmentary and enlarged view of the multi-level conveyer of FIG. 1 showing a carrier unit thereof passing a turn in the conveyer with its outer side abutting on a retainer wall. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Please refer to FIG. 1 in which a multi-level conveyer according to a preferred embodiment of the present invention is shown. The multi-level conveyer includes a plurality of serially arranged carrier units  10  and two parallel chains  20  continuously extended to separately and correspondingly locate before front end and behind rear end of the carrier units  10 . 
     Please refer to FIG. 2 that is a fragmentary and enlarged perspective of one carrier unit  10 . As shown, the carrier unit  10  includes a central pivotal shaft  11 , two ends of which separately project from the front and the rear ends of the carrier unit  10  to connect to the two chains  20 . Chain wheels  21  are provided in the conveyer at predetermined positions for the chains  20  to pass there and turn to a higher or a lower level. The chain wheels  21  and the chains  20  cooperate to move the carrier units  10  connected to the chains  20  from a bottom level of the conveyer to a top level thereof and then from the top level to sequentially pass every lower levels until the carrier units  10  reach the bottom level again to complete one cycle of conveyance on the multi-level conveyer. 
     As can be seen from FIG. 1, the chains  20  turn by 90 degrees in their moving direction when they pass a first chain wheel  21 . After the chains  20  have passed a second chain wheel  21  next to the first chain wheel  21 , their moving direction has turned by 180 degrees. At this point, the carrier units  10  are moved to a next higher or lower level on the multi-level conveyer. That is, by provision of chain wheels  21  at proper positions, the two continuous chains  20  and the carrier units  10  can together form a conveyer providing a multi-level conveyance path. A distance or height between any two levels of the conveyer may be properly decided depending on working pieces  30  to be positioned on the carrier units  10 . 
     FIG. 3 is a front elevation of the carrier unit  10 , and FIG. 4 is a sectional view of the carrier unit  10  taken on line  4 — 4  of FIG.  3 . As shown in FIG. 4, the pivotal shaft  11  of the carrier unit  10  has bushings  15  spaced around it before it is extended through a long hole provided on the carrier unit  10 . Therefore, the shaft  11  can revolve on its axis inside the long hole of the carrier unit  10 . When the chains  20  pass one of the chain wheels  21  and turn, the pivotal shaft  11  connected thereto revolves at the turning while it moves forward along the chains  20 . This allows the carrier unit  10  to which the pivotal shaft  11  is connected to always maintain in a horizontal position without dropping working pieces  30  positioned thereon. 
     Please refer to FIGS. 1 and 5 at the same time. Retainer walls  40  are provided at every turns of the multi-level conveyer to contact with an outer side (either a left or a right side) of the carrier unit  10  passing the turns to a higher or a lower level of the conveyer. The retainer wall  40  offsets an inertia force of the moving carrier unit  10  at the turning point, so that the carrier unit  10  would not rotate while turning. Moreover, retainer walls  40  are also provided along vertical conveyance paths in the multi-level conveyer to contact with one side of the carrier units  10  sequentially moving upward or downward along the chains  20 , preventing the carrier units  10  from rotating or tilting over during moving vertically. 
     Please now refer back to FIG.  2 . The carrier unit  10  is provided near front and rear ends of two lateral sides thereof with a pulley support  12  each. The pulley support  12  each includes a vertical bar portion  121 . Two pulleys  122  are separately mounted to upper and lower ends of the vertical bar portion  121 . When the carrier unit  10  passes by a retainer wall  40 , the upper and the lower pulleys  122  at one side thereof facing toward the retainer wall  40  would rotatably contact the retainer wall  40  to reduce a friction between the carrier unit  10  and the retainer wall  40 . Furthermore, contact of the pulleys  122  with the retainer wall  40  is also helpful in maintaining the carrier unit  10  in a stable horizontal position. 
     The carrier unit  10  is also provided at its front and rear ends separately with two spaced rollers  13  that project from the front and the rear end of the carrier unit  10 . In a normal condition, rollers  13  provided at two ends of the carrier unit  10  separately rotatably move on and along a lower rail  50 . However, two additional sections of upper rails  51  are provided near each turn on the multi-level conveyer corresponding to the lower rails  50 . When the carrier unit  10  moves to a turn with its rollers  13  located at outer side thereof becoming separated from the lower rails  50 , the rollers  13  would still be guided by the upper rails  51  without causing a tilted carrier unit  10 . The retainer walls  40  provided to one side of the vertical conveyance paths also function like rails. 
     As can be clearly seen from FIG. 1, the multi-level conveyer of the present invention includes a bottom and a second level that have a transversely extended distance longer than that of other higher levels to project two ends from the higher levels, so that working pieces  30  may be conveniently positioned on or removed from the carrier units  10  at the second level. 
     With the above arrangements, the multi-level conveyer of the present invention provides sufficient conveying length and time for working pieces on the conveyer to be fully dried while it can be mounted in a considerably small drying room. The multi-level conveyer of the present invention is therefore most economical and practical for use in drying rooms.