Patent Publication Number: US-9834987-B2

Title: Foldable picking ladder cart

Description:
The current application claims a foreign priority to application number 104206630 filed on Apr. 30, 2015 in Taiwan. 
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates generally to a conveying appliance used for warehousing, and more particularly to a foldable picking ladder cart. 
     2. Description of Related Art 
     In storage facilities such as warehouses, materials and goods are stocked on the shelves in different categories. For the convenience of conveying, picking ladder carts are commonly used in moving the materials and goods to and from the shelves, and especially in short-distance transportation. Additionally, a conventional picking ladder cart has a multilayered structure, or a large loading area, which provides a larger loading capacity to reduce the transportation cost. 
     However, with such design, a conventional picking ladder cart occupies a large space when it is not in use, which causes a waste of storage space. Moreover, it may become a threat to industrial safety when workers are walking in the storage facility. 
     BRIEF SUMMARY OF THE INVENTION 
     In view of the above, the primary objective of the present invention is to provide a foldable picking ladder cart to solve the problem of the waste of storage space. 
     The present invention provides a foldable picking ladder cart including a main shaft, an upper loading board, a lower loading board, an upper brace, and a lower brace. The upper loading board is pivotally connected to the main shaft, wherein the upper loading board is pivotally movable between a first position and a second position relative to the main shaft. The lower loading board is pivotally connected to another end of the main shaft, wherein the main shaft is pivotally movable between a third position and a fourth position relative to the lower loading board. A plurality of wheels are installed at a bottom of the lower loading board. The upper brace is pivotally connected to the upper loading board and the main shaft with two ends thereof respectively. The upper brace is pivotally movable between a supporting position and a folded position; when the upper brace is in the supporting position, the upper loading board is in the first position; when the upper brace is in the folded position, the upper loading board is in the second position. The lower brace is pivotally connected to the main shaft and the lower loading board with two ends thereof respectively. The lower brace is pivotally movable between a supporting position and a folded position; when the lower brace is in the supporting position, the main shaft is in the third position; when the lower brace is in the folded position, the main shaft is in the fourth position. 
     Whereby, with the design of the upper brace and the lower brace, when the upper and the lower braces are in the supporting positions, the braces can firmly support the main shaft and the upper loading board. When the foldable picking ladder cart is not in use, the braces are in the folded positions to reduce the occupied volume and the waste of storage space. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The present invention will be best understood by referring to the following detailed description of some illustrative embodiments in conjunction with the accompanying drawings, in which 
         FIG. 1  is a perspective view of a preferred embodiment of the present invention, showing the foldable picking ladder cart before being folded; 
         FIG. 2  is a partial enlarged view of the preferred embodiment, showing the relation of the first support and the second support of the lower brace in the supporting position; 
         FIG. 3  is a partial exploded view of  FIG. 2 ; 
         FIG. 4  is a sectional view along the 4-4 line in  FIG. 2 , showing the locking device is in the locking state; 
         FIG. 5  is a sectional view along the 4-4 line in  FIG. 2 , showing the locking device is in the unlocking state; 
         FIG. 6  to  FIG. 10  are lateral views of the preferred embodiment, showing the folding process of the foldable picking ladder cart; and 
         FIG. 11  is a perspective view of the preferred embodiment, showing the foldable picking ladder cart which is folded. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in  FIG. 1 , a foldable picking ladder cart  100  of the preferred embodiment of the present invention includes an upper loading board  10 , a lower loading board  20 , two main shafts  30 , two lower braces  40 , and two upper braces  50 . 
     Both the upper loading board  10  and the lower loading board  20  are rigid boards for holding goods, wherein a plurality of wheels  21  are installed at a bottom of the lower loading board  20 . The main shaft  30  has a stiff supporting structure, and pivotally connected to a first connecting member  12  of the upper loading board  10  and the first connecting member  22  of the lower loading board  20  with two ends thereof respectively. 
     The two lower braces  40  are the same in structure, wherein each of the lower braces  40  is pivotally connected to a second connecting member  22  of the lower loading board  20  and a connecting member  32  of the main shaft  30  with two ends thereof respectively. Each of the lower braces  40  includes a first support  42  and a second support  44  as shown in  FIG. 2  and  FIG. 3 . The first support  42  and the second support  44  are pivotally connected to each other through a shaft  40   a , wherein the shaft  40   a  is connected to the second support  44  with one end thereof, and passes through a washer  40   b  and a shaft bore  421  of the first support  42 , and is fixed to the first support  42  with the other end thereof through a fixing member; in the preferred embodiment, the fixing member is a cap nut  40   c . When the first support  42  and the second support  44  are arranged in a straight line with a straight angle formed between the two supports  42  and  44 , the lower brace is defined to be in a supporting position shown as  FIG. 6 . On the other hand, when the first support  42  and the second support  44  overlap, the lower brace is defined to be in a folded position shown as  FIG. 10 . 
     The first support  42  a is bent to form a stop piece  422  protruding toward the second support  44 , wherein an engaging portion  422   a  is formed on the stop piece  422 ; the second support  44  has a recession  442  thereon corresponding to the stop piece  422 . When the first support  42  and the second support  44  are arranged in a straight line, the stop piece  422  is fitted into the recession  442 , and the engaging portion  422   a  engages an outer surface of the second support  44 , which is illustrated in  FIG. 2 . With the design of the stop piece  422  and the corresponding recession  442 , the structural strength of the lower brace  40  is increased, which prevents a separation of the first support  42  and the second support  44  caused by an external force. 
     The foldable picking ladder cart  100  further has a locking device  60  installed on the lower brace  40 , depicted in  FIG. 3  and  FIG. 4 . The locking device  60  includes a positioning base  62 , a positioning pin  64 , a confining unit  66 , and a spring  68 , wherein the positioning base  62  has a hollow portion therein, and the first support  42  and the second support  44  have a positioning bore  424  and  444  respectively. The hollow portion of the positioning base  62  aligns with the positioning bore  424  of the first support  42 ; an end of the positioning base  62  is inserted into the positioning bore  424  of the support  42 , and is fixed to the first support  42 . 
     The positioning pin  64  has a body  642  and a head  644  connected to each other, wherein the body  642  is detachably inserted into the hollow portion of the positioning base  62  which is located in the positioning bore  424  of the first support  42 , and is also inserted into the positioning bore  444  of the second support  44 ; the head  644  abuts against another end of the positioning base  62 . 
     The confining unit  66  in the preferred embodiment includes a confining member  662  and a protruding ring  664 , wherein the confining member  662  is a ring fixed to an outer surface of the body  642 ; the protruding ring  664  is another ring fixed to an inner surface of the positioning base  62 , and is located in the hollow portion of the positioning base  62 . 
     The spring  68  is provide in the hollow portion of the positioning base  62 , and abuts against the confining member  662  and the protruding ring  664  with two ends thereof respectively. The spring  68  applies an elastic force to the positioning pin  64  to keep the body  642  of the positioning pin  64  staying in the positioning bore  444  of the second support  44 , and to keep the first support  42  and the second support  44  being arranged in a straight line, which is defined as a locking state of the locking device  60 . In such state, the first support  42  and the second support  44  are fixedly in the supporting position. 
     As shown in  FIG. 5 , when the positioning pin  64  is pulled against the elastic force of the spring  68  to leave the positioning bore  444  of the second support  44 , the first support  42  and the second support  44  are pivotally movable toward each other, which is defined as an unlocking state of the locking device  60 . 
     Each of the two upper braces  50  pivotally connected to a second connecting member  14  of the upper loading board  10  and the connecting member  32  of the main shaft  30  with two ends thereof respectively, which is illustrated in  FIG. 1 . Each of the upper braces  50  includes a third support  52  and a fourth support  54  connected to each other, wherein the connection relation of the two supports  52  and  54  are the same in the preferred embodiment. Similarly, a locking device is installed on the upper brace  50  to keep the two supports  52  and  54  being arranged in a straight line to be in a supporting position. The structural relation of the locking device and the upper brace  50  is the same as the locking device  60  and the lower brace  40 , and is not described in detail herein. 
     The foldable picking ladder cart  100  further includes a pair of handles  70  and a ladder  80 . Each of the handles  70  is connected to the main shaft  30  with an end thereof, and the other end is a free end to be gripped by a user to control the foldable picking ladder cart  100 . The ladder  80  is connected to the main shaft  30 , and includes a plurality of steps arranged at intervals for a user to step on. 
     The folding process of the upper loading board  10  is illustrated in  FIG. 6  to  FIG. 8 . When the locking device of the upper brace  50  is in an unlocking state, the upper loading board  10  is pivotally movable between a first position P 1  and a second position P 2  relative to the main shaft  30 . On the other hand, the upper brace  50  is moved from the supporting position to a folded position when the upper loading board  10  is moved from the first position P 1  to the second position P 2 . Next, the folding process of the main shaft  30  is illustrated in  FIG. 8  to  FIG. 10 . When the locking device  60  of the lower brace  40  is in the unlocking state, the main shaft  30  is pivotally movable between a third position P 3  and a fourth position P 4  relative to the lower loading board  20 ; at the same time, the lower brace  40  is moved from the supporting position to the folded position, and the foldable picking ladder cart  100  is completely folded as shown in  FIG. 11 . 
     With the design of the lower brace  40  and the upper brace  50 , the foldable picking ladder cart  100  is stable for loading goods through the support of the two braces  40  and  50 . On the other hand, when the foldable picking ladder cart  100  is not in use, it can be folded in the way of the abovementioned folding process to reduce the occupied volume without detaching any parts thereof. 
     Additionally, the process from the folded state to the supporting state of the foldable picking ladder cart  100  is the reverse of the folding process shown from  FIG. 6  to  FIG. 10 . 
     In addition, the connection relation of the supports of the braces is not limited to the way mentioned above. For example, using the washer  40   b  could reduce the friction generated by the pivotal moving of the supports, while in other embodiments, the washer  40   b  could be omitted. Furthermore, the supports connected by the shaft  40   a  and the cap nut  40   c  could be fixedly connected by a bolt and a nut, or a rivet, in other embodiments. 
     Additionally, for other embodiment with a simpler structure, the locking device  60  could be substituted by other locking members, such as carabiners and D buckles. 
     It must be pointed out that the embodiment described above is only a preferred embodiment of the present invention. All equivalent structures which employ the concepts disclosed in this specification and the appended claims should fall within the scope of the present invention.