Abstract:
A vertical conveyor that includes a frame, a carriage, and a drive mechanism. The frame includes a vertical support member, and the carriage is coupled to the frame to carry a load. The carriage is mounted for movement along the vertical support member. The drive mechanism includes a first actuator and a second actuator. The first actuator includes a cylinder and a rod that extends from the cylinder to raise the carriage. The second actuator includes a cylinder and a rod each having lengths greater than lengths of the cylinder and rod of the first actuator. The rod of the second actuator extends from the cylinder of the second actuator to raise the carriage and the cylinder of the first actuator.

Description:
BACKGROUND 
       [0001]    The present invention relates to a vertical conveyor that can be employed in warehouses, factories, and the like to convey material or cargo between different vertical levels. 
         [0002]    A typical vertical conveyor includes a carriage mounted for vertical movement on a frame or supporting structure and that is adapted to support cargo. In some types of vertical conveyors, the carriage is either straddled between two vertical columns of the frame or is cantilevered outward from the columns and guided for vertical movement on the columns. The carriage is lifted by a pulling force from at least one hydraulic cylinder having an upper end secured near the top of the conveyor (e.g., to the top of a column or to a ceiling) and a lower end secured to the carriage. In operation, the hydraulic cylinder retracts to pull the carriage upward. 
       SUMMARY 
       [0003]    The present invention provides a vertical conveyor that includes a frame, a carriage, and a drive mechanism. The frame includes a vertical support member, and the carriage is coupled to the frame to carry a load. The carriage is mounted for movement along the vertical support member. The drive mechanism includes a first actuator and a second actuator. The first actuator includes a cylinder and a rod that extends from the cylinder to raise the carriage. The second actuator includes a cylinder and a rod having lengths greater than lengths of the cylinder and rod of the first actuator. The rod of the second actuator extends from the cylinder of the second actuator to raise the carriage and the cylinder of the first actuator. 
         [0004]    In another embodiment, the present invention provides a vertical conveyor that includes a frame, a carriage, a first actuator, and a second actuator. The frame includes a vertical support member, and the carriage is coupled to the frame to carry a load. The carriage is mounted for movement along the vertical support member. The first actuator includes a cylinder and a rod that extends from the cylinder. The second actuator includes a cylinder and a rod that extends from the cylinder of the second actuator, and wherein the cylinder of the first actuator is coupled to the cylinder of the first actuator in a side-by-side relation. 
         [0005]    In another embodiment the invention provides a method of raising a carriage from a lowered position to a raised position. The carriage is coupled to a frame for movement along a vertical support member of the frame. The method includes raising the carriage from the lowered position to an intermediate position by extending one of a first actuator and a second actuator. The method further includes raising the carriage from the intermediate position to the raised position by extending the other of the first actuator and the second actuator, the first actuator including a cylinder having a length and the second actuator including a cylinder having a length that is greater than the length of the cylinder of the first actuator. 
         [0006]    Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1   a  is a front perspective view of a vertical conveyor embodying the present invention with a carriage in a lowered position. 
           [0008]      FIG. 1   b  is a front perspective view of the vertical conveyor shown in  FIG. 1   a  with the carriage in an intermediate position. 
           [0009]      FIG. 1   c  is a front perspective view of the vertical conveyor shown in  FIG. 1   a  with the carriage in a raised position. 
           [0010]      FIG. 2  is a perspective view of the carriage of  FIG. 1   a.    
           [0011]      FIG. 3  is a section view taken along line  3 - 3  of  FIG. 1   a.    
           [0012]      FIG. 4  is a partial front view of the vertical conveyor shown in  FIG. 1   a.    
           [0013]      FIG. 5  is a section view taken along line  5 - 5  of  FIG. 1   a.    
           [0014]      FIG. 6  is an enlarged perspective view taken at line  6 - 6  of  FIG. 1   a.    
           [0015]      FIG. 7  is a front perspective view of an alternative construction of the vertical conveyor shown in  FIG. 1   a  with the carriage in the raised position. 
       
    
    
       [0016]    Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,”“supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. 
       DETAILED DESCRIPTION 
       [0017]      FIG. 1   a  illustrates a vertical conveyor  10  that is adapted to move materials or cargo between different vertical levels. For example, the vertical conveyor  10  can move materials from a lower floor or level to an upper floor or level. The vertical conveyor  10  includes a frame  13  having vertical support members that include both short vertical supports  16  and long vertical supports  19 . While the illustrated conveyor  10  includes both the long and short supports  19 ,  16  in other constructions the conveyor may include vertical supports that are generally the same length. 
         [0018]    The lower ends of the short and long vertical supports  16 ,  19  are supported by bases  21 . The bases  21  can be coupled to a foundation or floor using anchor bolts, a welded connection, and the like. The frame  13 , the bases  21 , and the long and short vertical supports  19 ,  16  can be formed from any suitable material, such as aluminum, steel, plastic, etc. 
         [0019]    The long vertical supports  19  can be formed with the base  21 , or can be coupled to the base  21  through the use of fasteners, welded connections, and the like. In the illustrated embodiment, the long vertical supports  19  are modified I-beams that define a channel  24 . While the illustrated conveyor  10  includes a pair of long supports  19 , in other constructions the conveyor can include one or more than two long supports. 
         [0020]    The short vertical supports  16  can be integrally molded, fastened, or welded to the bases  21  and/or the long vertical supports  19 . The illustrated short vertical supports  16  define a channel with a generally C-shaped cross section. While the illustrated short vertical supports  16  are coupled to a side, or a flange, of the long vertical supports  19 , in other constructions, the short vertical supports  16  can be coupled to other locations. Furthermore, while the illustrated conveyor  10  includes a pair of short supports  16 , in other constructions the conveyor may include one or more than two short supports. 
         [0021]    The vertical conveyor  10  also includes a carriage  27  having a height H 1 . Referring to  FIG. 2 , the carriage  27  includes a generally flat platform  30  adapted to support a load or cargo. The carriage  27  also includes side supports  33  for supporting the carriage  27 . The side supports  33  are connected by a top support  36  to help stabilize the carriage  27 , and reinforcing supports  39  are secured between the platform  30  and the side supports  33  and are angled to stabilize the carriage  27  and help the carriage  27  to accommodate excessive torque due to an uneven load. 
         [0022]    With continued reference to  FIG. 2 , the illustrated carriage  27  includes four sets of wheels or rollers  42 . Each set of rollers  42  includes a first roller  45  and a second roller  48 . The first roller  45  is journaled on a shaft  51  that extends generally normal from the side support  33 . The second roller  48  is coupled to the side support such that the second roller rotates about an axis that is generally normal the shaft  51  of the first roller  45 . 
         [0023]    Referring to  FIGS. 3 and 4 , the carriage  27  is placed between the short and long vertical supports  16 ,  19  of the vertical conveyor  10 . As illustrated in  FIG. 3 , the first and second rollers  45 ,  48  of the carriage  27  are located within the channel  24  of the long vertical support  19 . The first and second rollers  45 ,  48  roll along inside surfaces of the channels  24  to allow the carriage  27  to travel in the directions indicated by the arrows Y, and to substantially prevent movement, or stabilize, the carriage  27  in directions indicated by the arrows X. 
         [0024]    Referring to  FIG. 5 , the vertical conveyor  10  further includes a pair of long hydraulic actuators  54  having a length L 1  and positioned on opposing sides of the carriage  27 . Each long hydraulic actuator  54  includes a long cylinder  57  and a long rod  60  connected to a piston inside the long cylinder  57 . A lower end of each long rod  60  is secured to the base  21  using a lower clevis mount  63 . The long cylinders  57  have a length L 2  and, because  FIG. 5  illustrates the long actuator  54  in a retracted position (i.e., minimum length), the length L 1  of the long actuators  54  are approximately equal to the length L 2  of the long cylinders  57 . The piston is configured to extend the long rod  60  out of the long cylinder  57  to change the length L 1  of the long hydraulic actuator  54 , and the illustrated long hydraulic actuator  54  can extend to a maximum length that is approximately equal to the twice the length L 2  of the long cylinder  57 . 
         [0025]    A pair of short hydraulic actuators  66  having a length L 3  are positioned on opposing sides of the carriage  27  and adjacent to a corresponding long hydraulic actuator  54 . Each short hydraulic actuator  66  includes a short cylinder  68  and a short rod  72  connected to a piston inside the short cylinder  68 . In the illustrated construction each short cylinder  68  is coupled to the adjacent long cylinder  57  in a side-by-side relationship. Furthermore, the cylinders  68 ,  57  of the short and long actuators  66 ,  54  each include a lower end  74 , and in the illustrated construction the lower ends  74  of the cylinders  68 ,  57  are adjacent each other. The upper end of each short rod  72  is coupled to an upper flange of the carriage  27  using an upper clevis mount  75 . 
         [0026]    While the illustrated vertical conveyor  10  of  FIGS. 1   a - 6  includes the pair of short hydraulic actuators  66  and the pair of long hydraulic actuators  54 , in other constructions the vertical conveyor can include any suitable number of long and short hydraulic actuators  54 ,  66 . For example,  FIG. 7  illustrates a vertical conveyor  10 ′ that includes one long hydraulic actuator  54 ′ and one short hydraulic actuator  66 ′. The remaining parts of the vertical conveyor  10 ′ are substantially similar to the vertical conveyor  10 , and like parts have been given the same reference number plus a prime symbol. 
         [0027]    The illustrated short cylinders  68  have a length L 4  and, because  FIG. 5  illustrates the short actuators  66  in a retracted position (i.e., minimum length), the length L 3  of the short actuators  66  are approximately equal to the length L 4  of the short cylinders  68 . The piston is configured to extend the short rod  72  out of the short cylinder  68  to change the length L 3  of the short hydraulic actuator  66 . The illustrated short hydraulic actuator  66  can extend to a maximum length that is approximately equal to the twice the length L 4  of the short cylinder  68 . 
         [0028]    Referring to  FIG. 4 , a guide flange  78  is secured to each pair of short and long cylinders  68 ,  57 .  FIG. 6  illustrates and enlarged view of one of the guide flanges  78 . Each guide flange  78  includes an anti-friction pad  81  that is slidably supported within the c-shaped channel of the corresponding short vertical support  16 . The anti-friction pad  81  can be formed from, or coated with, any suitable material, such as TEFLON, graphite, and the like, to reduce the friction between the pad  81  and the short vertical support  16 . In other constructions, the guide flange  78  may include a wheel, roller, or other suitable device alone or in combination with the pad  81 . The pad  81  and guide flange  78  provide guidance to the lower ends of the short and long cylinders  68 ,  57 . 
         [0029]    While operation of the vertical conveyor will be described with reference to the vertical conveyor  10  of  FIGS. 1   a - 6 , it should be understood that the operation of the vertical conveyor  10 ′ of  FIG. 7  is substantially the same as the operation of the vertical conveyor  10 . 
         [0030]    In operation, the carriage  27  is moved from a lowered position ( FIG. 1   a ) to a raised position ( FIG. 1   c ) by actuating the long hydraulic actuators  54  and the short hydraulic actuators  66  to change their lengths L 1 , L 3 . This can occur by actuating all of the hydraulic actuators simultaneously so that both the short hydraulic actuators  66  and the long hydraulic actuators  54  extend the rods  60 ,  72  from the cylinders  57 ,  68  at generally the same time. Alternatively, one pair of hydraulic actuators (either the pair of short hydraulic actuators  66  or the pair of long hydraulic actuators  54 ) can be actuated first, followed by actuation of the other pair of hydraulic actuators. 
         [0031]    In the illustrated embodiment, the long hydraulic actuators  54  are actuated first, resulting in the carriage  27  moving from the lowered position ( FIG. 1   a ) to an intermediate position ( FIG. 1   b ). During actuation of the long hydraulic actuators  54 , the long rods  60  are forced out of the long cylinders  57 , resulting in the long cylinders  57  being raised. Because the long cylinders  57  are secured to the short cylinders  68 , and further because the short cylinders  68  are coupled to the carriage  27 , the carriage  27  is raised a distance D 1  that is approximately equal to the length L 2  of the long cyclinders  57  when the long hydraulic actuators  54  are extended to their maximum length L 1 ′. 
         [0032]    After the long hydraulic actuators  54  have been fully actuated, the short hydraulic actuators  66  are actuated to raise the carriage  27  from the intermediate position ( FIG. 1   b ) to the raised position ( FIG. 1   c ). During this process, the short rods  72  are extended upwardly from the short cylinders  68 . Because the upper ends of the short rods  72  are secured to the carriage  27 , the carriage is raised an additional distance D 2  that is approximately equal to the length L 3  of the short cylinders  68 . Therefore, the top of the carriage  27  has been raised to a height H 2  that is approximately equal to twice the length L 2  of the long cylinders  57  or approximately equal to the maximum length L 1 ′ of the long hydraulic actuators  54 . The carriage  27  can then be lowered by reversing actuation of the hydraulic actuators  54 ,  66 . 
         [0033]    Referring to  FIG. 1   c , the illustrated arrangement of the long and short hydraulic actuators  54 ,  66  allows the user to raise the carriage platform  30  a total distance D 3  that is approximately equal to the length L 2  of the long cylinders  57  ( FIG. 1   a ) plus the length L 4  of the short cylinders  68 . Furthermore, the illustrated arrangement of the long and short hydraulic actuators  54 ,  66  allows the user to raise the platform  30  the distance D 3  while the maximum length L 1 ′ of the long hydraulic actuators  54  is approximately equal to the height H 2  of the top of the carriage  27  at the raised position. In one application, the vertical conveyor  10  can be utilized in a building having a roof or ceiling, and because the long hydraulic actuators  54  generally do not extend above the carriage  27  in the raised position, the amount of overhead distance between the roof or ceiling and the vertical conveyor  10  is reduced when compared to vertical conveyors that utilize actuators that extend above the carriage in the raised position. 
         [0034]    In one application of the vertical conveyor  10 , it is desirable to maximize the height H 1  of the carriage  27 , which would be approximately equal to the distance between the ceiling and the uppermost floor that the vertical conveyor reaches. Utilizing the illustrated vertical conveyor  10 , with the long and short hydraulic actuators  54 ,  66 , the maximum travel of the platform  30  is the distance D 3  that is approximately equal to three times the height H 1  of the carriage  27 . Whereas, if the vertical conveyor utilized hydraulic actuators of equal length, the maximum travel of the platform would only be twice the height H 1  of the carriage  27 . 
         [0035]    While the illustrated vertical conveyor is only shown with the carriage  27  in three positions, the lowered position ( FIG. 1   a ), the intermediate position ( FIG. 1   b ), and the raised position ( FIG. 1   c ), it should be understood that the vertical conveyor  10  can be operated to position the carriage  27  at any location between the lowered position ( FIG. 1   a ) and the raised position ( FIG. 1   c ). 
         [0036]    In one construction of the conveyor  10 , all of the hydraulic actuators  54 ,  66  are provided with pressurized hydraulic fluid from a common source. In one such construction, the short hydraulic actuators  66  have the same diameter as the long hydraulic actuators  54 , thus resulting in approximately the same force being provided when pressurized hydraulic fluid is supplied. In this construction, the short hydraulic actuators  66  are lifting the weight of the carriage  27  and cargo, while the long hydraulic actuators  54  are lifting the weight of the carriage  27 , the cargo, the short hydraulic actuators  66 , and the long cylinders  57 . As a result, when the pressurized hydraulic fluid is provided to all of the hydraulic actuators  54 ,  66 , the short hydraulic actuators  66  will start moving first due to the hydraulic fluid seeking the path of least resistance. After the short hydraulic actuators  66  have been fully extended, the hydraulic fluid will move the long hydraulic actuators  54  resulting in extension of the long rods  60 .