Patent Publication Number: US-10322920-B2

Title: Scissor-boom lift

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to copending Chinese Application, Serial No. ZL 2016 2 20250971.6, filed on Mar. 29, 2016, which is hereby incorporated by reference for all purposes. 
     BACKGROUND 
     The present disclosure relates generally to lifting devices. In particular, a scissor-boom lift is described. 
     Known lifting devices are currently grouped into 2 categories: (1) The scissor lifts, which use the scissor links folding and unfolding to change the lifts height and they have no far outreach capability (2) The boom lifts, which use the telescope booms&#39; extension, retraction and angel movement to change the lifts top platform height and outreach distance. Current lifts are not entirely satisfactory for the range of applications in which they are employed. For example, scissor lifts do not have far outreach capability and thus their application are very limited. Boom lifts are complicated to operate and expensive to own. 
     Thus, there exists a need for lifting devices that improve upon and advance the design of known lifting devices. Examples of new and useful lifting device relevant to the needs existing in the field are discussed below. 
     Examples of references relevant to lifting means include U.S. Pat. Nos. 6,330,933; 4,691,805, and 5,740,887. The complete disclosures of the above patents and patent applications are herein incorporated by reference for all purposes. 
     SUMMARY 
     The present disclosure is directed to a scissor-boom lift. In some examples, scissor-boom lift includes a scissor boom assembly having a horizontal telescopic boom assembly at the top including a base-boom, a middle-boom, and a top-boom which also acts as the platform, a scissor links assembly in the middle, and a chassis at the bottom. The 3-section horizontal telescope boom, powered by a power hoist, can extend or retract to change the platform&#39;s outreach distance. The scissor links, powered by a hydraulic cylinder, can fold and unfold to change the platform&#39;s working height. The chassis, with 2 front steering wheels and 2 rear wheels, allows the scissor-boom lift to travel and turn. All above mentioned movement can be controlled separately by a single joystick located inside the platform. 
     Compared to the current scissor lifts on the markets, the scissor-boom lift provides an outreach capability when the 3 section horizontal telescopic boom extend out and thus can reach those working objects that scissor lifts cannot reach. Compared to the current boom lifts on the market, the scissor-boom lift is much cheaper in cost and also simpler to control and maintain. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a first example of a scissor-boom lift in an in-use condition, an operator operating the device via a handheld controller; the device in a raised position. 
         FIG. 2  is a perspective view of the scissor-boom lift shown in  FIG. 1  depicting the device in a stored position for transport. 
         FIG. 3  is a perspective view of the scissor-boom lift showing the device horizontal and vertical movement range with indication arrows between stored position and the fully extended and raised position. 
         FIG. 4  is a perspective view of a second example of a scissor-boom lift including the top section of the device moving horizontally out and up from the lowered portion. 
         FIG. 5  is a perspective view of a second example of a scissor-boom lift including the top section of the device moving horizontally in and down from the raised portion. 
         FIG. 6  is a perspective view of the telescopic middle-boom extent and retract movement mechanism of the scissor-boom lift. 
         FIG. 7  is a perspective view of the telescopic top-boom simultaneous extending mechanism of the scissor-boom lift. 
         FIG. 8  is a perspective view of the telescopic top-boom simultaneous retracting mechanism of the scissor-boom lift. 
         FIG. 9  is a perspective view of the top-boom, middle boom and base boom major structure. 
         FIG. 10  is a sectioned view to show telescopic boom assembly connection to the scissor links and also the control cable retractable drum and bracket layout on the telescopic boom assembly. 
         FIG. 11  is perspective view of the scissor links assembly and its connection to the telescopic boom assembly at the top and to the chassis at the bottom. 
         FIG. 12  is the perspective view of the chassis. 
         FIG. 13  is the perspective view of the single joystick controller controlling all the scissor-boom lift&#39;s movement. 
     
    
    
     DETAILED DESCRIPTION 
     The disclosed lifting device will become better understood through review of the following detailed description in conjunction with the figures. The detailed description and figures provide merely examples of the various inventions described herein. Those skilled in the art will understand that the disclosed examples may be varied, modified, and altered without departing from the scope of the inventions described herein. Many variations are contemplated for different applications and design considerations; however, for the sake of brevity, each and every contemplated variation is not individually described in the following detailed description. 
     Throughout the following detailed description, examples of various lifting devices are provided. Related features in the examples may be identical, similar, or dissimilar in different examples. For the sake of brevity, related features will not be redundantly explained in each example. Instead, the use of related feature names will cue the reader that the feature with a related feature name may be similar to the related feature in an example explained previously. Features specific to a given example will be described in that particular example. The reader should understand that a given feature need not be the same or similar to the specific portrayal of a related feature in any given figure or example. 
     Generally speaking, the present invention refers to a new scissor-boom lift as shown in  FIG. 1  which includes a 3-section telescopic boom  120  at the top that can extents or retracts horizontally, a scissor link assembly  130  in the ‘mid’ that can fold or unfold vertically and a chassis  140  at the bottom that can travel or turn. Each of these movements can be controlled separately by a joystick controller located inside the working platform. 
     With reference now to  FIGS. 1-5 , a first example of a scissor-boom lift  100 ; scissor-boom lift  100 , will now be described. Scissor-boom lift  100  functions to provide an adjustable work platform with vertical-movement and horizontal-movement of the work platform, as desired. The reader will appreciate from the figures and description below that scissor-boom lift  100  addresses shortcomings of conventional lifting devices. As shown in  FIG. 1 , a scissor-boom lift  100  at a fully extended and raised position is disclosed herein including a telescopic boom assembly  120  at the top including a base-boom  122 , a middle-boom  124 , and a top-boom  126 , a scissor links assembly  130  in the middle, and a chassis  140  at the bottom.  FIG. 2  shows the scissor-boom lift  100  in a stored position, with the top telescopic boom section  120  fully retracted and the scissor links  130  fully folded. 
     The telescope boom assembly  120 , is coupled to the scissor links assembly  130  and powered by power hoist  160  located at the front end of base boom  122 , providing a stable work platform for workers as shown in  FIG. 1  and also provides for horizontal-movement of a work platform as shown in  FIGS. 3-5 .  FIG. 3  shows the range of vertical and horizontal movement of the platform from stored position to the fully extended and raised position. The scissor links assembly  130 , powered by hydraulic cylinder, supports the top telescopic boom assembly  120  and provides the vertical-movement of the work platform. The chassis  140  supports the scissor link assembly  130  and can travel and turn. It also supports the counterweights at the front end to counterbalance the tipping moment. 
       FIG. 4  shows the telescopic boom assembly  120  making the simultaneously extension and the scissor links unfolding movement from retracted and lowered position to the extended and raised position and  FIG. 5  shows the telescopic boom assembly  120  making the simultaneously retraction and the scissor links folding movement from extended and raised position to the retracted and lowered position. The details of the telescopic boom assembly  120 , the scissor link assembly  130  and the chassis  140  will be depicted below with reference to the drawings. 
     Telescopic boom assembly  120 , as shown in  FIG. 1 ; the 3-section telescopic boom assembly  120  includes the base-boom  122 , the middle-boom  124 , and the top-boom  126 . The top-boom  126  also acts as the platform for a worker. As shown in  FIG. 9 , the base-boom  122  has a top-base-boom-channel  141  on top right side and top left side allowing the middle-boom  124  to nest in and slide along the top-base-boom-channel  141 . The base-boom  122  also includes the pivot pin bracket  143  at the bottom front to pivot to a top front scissor link  135  ( 135  will be described subsequently). 
     The base-boom  122  has a bottom-base-boom-channel  142  at bottom left side and bottom right side of the rear half that allows a top rear link  138  to sit in through a sliding block  185  ( 138  and  185  will be described subsequently) and slide along the base-boom-channel  142  when the scissor links assembly  130  folds and unfolds. The base-boom  122  further includes the control cable bracket  171  at the front end for holding the control cable when the platform extends and retracts. The top of the base-boom  122  are open so the top-boom  126  and middle-boom  124  can slide all the way into the top open space when fully retracted. 
     A power hoist  160  is preferably mounted at the front bottom of the base-boom  122  to provide power for telescopic boom assembly  120 &#39;s extension and retraction. As shown in  FIG. 9 , the middle-boom  124  has a middle-boom-channel  144  on both sides of the top allowing the top-boom  126  to sit in and slide along when the top-boom  126  extends and retracts. The outside of the middle-boom-channel  144  sits inside the top base-boom-channel  141  and slide along when middle-boom  124  extends and retracts. The middle boom  124  also comprises an extension cable vertical pulley  145  mounted at the rear end inside the right and left middle-boom-channel  144 . The middle-boom  124  also comprises a retraction cable pulley  146  mounted at the left and right side of a cross beam  147  at the bottom close to the front end of the middle-boom  124 . The middle-boom  124  further comprises a control cable retractable drum  173  mounted at a front end of the middle-boom  124 . 
     As shown in  FIG. 9 , the top-boom  126  has a working floor  176  and rail  177  on the top rear half of top-boom  126  that form a working platform allowing an operator to stand during work. A control box  190  is hanged on the rail  177 . The top-boom  126  also has the walking surface  178  at the front end of the top-boom  126  that allows the operator to walk through to get in or leave the working platform. A sliding block  180  is pivoted to each side of the top boom  126  at the front end and the sliding block  180  is fitted into the middle-boom-channel  144  allowing the top-boom  126  to slide along the middle-boom-channel  144 . An extension cable horizontal pulley  167  is mounted on each side of the top boom  126  next to the sliding block  180 . 
       FIG. 6  illustrates how the middle-boom  124  extents and retracts; a middle-boom extension cable  161  and a middle-boom retraction cable  162  are mounted to the power hoist  160  on one end, with one cable wrapping to the power hoist  160  from the bottom and the other cable wrapping to the power hoist  160  from the top so at any time when the power hoist  160  rotates, one cable will be wrapped into and the other one will be wrapped out from the power hoist  160 . The other end of the middle-boom extension cable  161  goes over a cable pulley  163  mounted at the bottom rear end of base-boom  122 , turns 180 degree there and then is fixed to the cross beam  147  on the middle-boom  124 . 
     The other end of the middle-boom retraction cable  162  is directly fixed to the cross beam  147 . The power hoist  160 , middle-boom extension cable  161 , cable pulley  163 , cross beam  147  and middle-boom retraction cable  162  form a closed loop. When the power hoist  160  rotates, if the middle-boom extension cable  161  is wrapped into the power hoist  160 , it will pull the cross-beam  146  away from the power hoist  160  through cable pulley  163  and thus the middle-boom  124  will extend out of the base-boom  122 ; if the middle-boom retraction cable  162  is wrapped into the power hoist  160 , it will pull the cross-beam  146  toward power hoist  160  directly and thus the middle-boom  124  will retract into the base-boom  122 . The operator can control the middle-boom  124 &#39;s extension or retraction by controlling the power hoist  160  rotation direction through control box  190 . 
     As shown in  FIG. 7 , the top-boom  126  extends simultaneously when middle-boom  124  extends since a top-boom extension cable  165  is used to push top-boom  126  out of middle-boom  124  when middle-boom  124  extents. The path of the top boom extension cable  165  starts with its one end fixed to the right front end of the base boom  122 , the other end goes inside and along the base-boom top channel  141  and middle-boom channel  144  on the right side to wrap on the right extension vertical pulley  145  located at the rear end of the middle-boom channel  124  and makes the 180 degree turn, then it wraps onto the right horizontal pulley  167  located at the front bottom of top-boom  126  and makes a 90 degree turn to wrap onto the left horizontal pulley  167 , it turns 90 degree again there and then goes to wrap onto the left extension vertical pulley  145  located at the rear end the middle-boom  124  on the other side. Then it goes inside and along the middle-boom channel  144  and base-boom top channel  141  on this side and finally is fixed to the front end of base-boom  122 . When the power hoist  160  rotates and pushes middle-boom  124  to extend backwardly, the right and left extension vertical pulley  145  move together with middle-boom  124  and thus will push the top boom extension cable  165  to move backward also. Since the two ends of the top boom extension cable  165  are fixed to the base-boom  122 &#39;s front end and thus do not move, then the middle section of the top boom extension cable  165  that goes between the right and left extension horizontal pulley  167  of the top-boom  126  will move backward at the double speed of the middle-boom  124  and thus push the top-boom  126  to extent simultaneously out of the middle-boom  124  when middle-boom  124  extends. 
     As shown in  FIG. 8 , the top-boom  126  retracts simultaneously when the middle-boom  124  retracts since a top-boom retraction cable  168  is used to pull the top-boom  126  back to middle-boom  124  simultaneously when middle-boom  124  retracts. The path of the top-boom retraction cable  168  starts with its one end anchored to the right bottom at the front half of the top-boom  126 , the other end of the retraction cable  168  goes through the bottom of the middle-boom  124  and wraps onto the top boom retraction pulley  146  mounted at the cross beam  147  at the bottom right front of the middle-boom  124  and makes 180 degree turn. It then passes through the right horizontal pulley  170  mounted at the rear end of base-boom  122  and makes 90 degree turns to go to the other horizontal pulley  170  on the left and makes another 90 degree turn there. It then passes through the other pulley  169  mounted at the bottom left front of the middle-boom  124 , makes 180 degree turns there and then goes through the bottom of the middle-boom  124  and then finally be anchored to the left bottom at the front half of top-boom  126 . 
     When the middle-boom  124  retracts into the base-boom  122 , the two top boom retraction cable pulleys  169  mounted at the bottom front of the middle-boom  124  move together with the middle-boom  124  and thus pull the top boom retraction cable  168  to move toward the front end of the base-boom  122 . Since the middle section of the top boom retraction cable  168  that goes between the two horizontal pulley  170  mounted at the bottom rear of the base-boom  122  will not move, the two end of the top boom retraction cable  168  that are anchored to the top-boom  126 &#39;s bottom front will be pulled at the double speed of the middle-boom  124  retraction movement and thus the top-boom  126  is then pulled simultaneously to move towards the front end of the base-boom  122  when middle-boom  124  retracts. 
     The control box  190  is preferably located on the top-boom  126  and is connected to the scissor links assembly  130  and chassis  140  by control cable  175 . As shown in  FIG. 10 , when the top-boom  126  extends or retracts, the control cable  175  will also expend or retract together with the top-boom  126 . This is accomplished by a front cable bracket  172  mounted at the front end of base-boom  122 , a rear cable bracket  174  mounted at the front half of the top-boom  126  and a retractable cable drum  173  mounted at the front end of middle-boom  124 . The control cable  175 &#39;s front end is fixed to the front cable bracket  172  on the base-boom  122 , the rear end of the control cable  175  is rewound into the right half of the retractable cable drum  173  from the top for several rounds, then is turned 180 degree to be rewound to the left half of the retractable cable drum  173  for several rounds and is rewound out of the retractable cable drum  173  from the bottom and then anchored to the cable rear end bracket  174  on the top-boom  126  at the rear end. Since the control cable  175  is rewound into the retractable cable drum  173  from the top and rewound out from the bottom, so when retractable cable drum  173  rotates, it will rewind or unwind the top and bottom cable simultaneously in opposite direction. 
     The retractable cable drum  173  always rewinds the cable to its drum by either the springs or motor inside the drum and thus there is always tension on the control cable  175  to make it ‘straight’ all the time. When the middle-boom  124  extends, the top-boom  126  also extends twice the speed of the middle-boom  124  so the control cable  175  is pulled out from the retractable cable drum  173  from both the top and bottom when the middle-boom  124  and the top-boom  126  extend. When the middle-boom  124  and the top-boom  126  retracts, the control cable  175  is also retracted to the retractable cable drum  173  by the forces of springs or motor inside the drums from both the top and bottom. 
     As shown in  FIG. 13 , the control box  190  comprises of a joystick  191  and rock switch  192  that control both the chassis  140 &#39;s travel and steering movement, as well as the top boom  126 &#39;s vertical and horizontal movement. Also as shown in  FIG. 12 , on the control box  190 , there are two control push buttons—travel control button  193  and platform control button  194  that can be selected to allow the operator to select which movement control to select. If the “Travel Control” button  193  is pushed, then the joystick  191  will control the chassis  140 &#39;s forward and backward travel and the rock switch  192  will control the front wheels steering direction. If the “Platform Control”  194  button is pushed, then the joystick  191  will control the scissor links unfold or fold movement, allowing the platform to go up or down and the rock switch  192  will control the extension or retraction of the telescopic boom assembly  120 &#39;s extension or retraction on the top, allowing the platform to outreach or retract in. 
     Referring now more specifically to scissor link assembly  130  as shown in  FIG. 11 ; the scissor link assembly  130  includes a top front link  139  that is pivoted to the base-boom front bottom pin bracket  143  by pin  183 , a top rear link  138  that is pivoted to a top sliding block  185  through a top pin  182 . The sliding block  185  is fitted inside and can slide along the base bottom sliding channel  142  located at the bottom rear half of the base-boom  122 . When scissor link assembly  130  folds and unfolds, since the top front link  139  is pivoted to the base-boom  122 &#39;s front end by pin  183 , so the top pin  182  of the top rear link  138  will slide along the base bottom sliding channel  142  on the base-boom  122  through sliding block  185 . 
     Also as shown in  FIG. 11 , the scissor link assembly  130  includes a bottom rear link  131  with a bottom rear pin  132 , a middle link  133  with a bottom middle pin  134  and top middle pin  137 , and a bottom front link  135  with a bottom front pin  136 . Bottom rear pin  132  and bottom front pin  136  fit inside can slide along the channel  143  ( 143  will be described late) on the chassis  140  through the bottom sliding block  186 . The middle link  133 &#39;s bottom end is pivoted to the chassis  140  by bottom middle pin  134  and the top end is pivoted to the bottom front link  135  by top middle pin  137 . The center of rear bottom pin  132 , the middle bottom pin  134  and the front bottom pin  136  are on the same horizontal surface and the middle link  133  is always parallel to bottom rear link  131  so when scissor links assembly  130  fold and unfold, the middle link  133  will swing around its bottom pivot link  134  and the rear bottom pin  132  and front bottom pin  136  will either move towards each other or apart from each other simultaneously and symmetrically with bottom middle pin  134  as the symmetric center. Thus the gravity center of the scissor links assembly  130  keeps unchanged and always stay at the center of the chassis  140 . 
     In reference to the scissor links assembly  130 , all scissor links pivot holes are preferably aligned horizontally except the top rear link  138  and top front link  139 &#39;s top pivot pin  182  and  183  that connect the scissor links assembly  130  to the top base-boom  122 . As shown in  FIG. 10 ; the center of the top rear link pivot pin  182  is above that of the top front link pivot pin  183 , causing the base-boom  122  not level, with its rear end tilted up by an angle α. As shown in  FIG. 10 , when the scissor links unfold and thus base boom  122  is raised up, the top sliding-block  185  and top rear pivot pin  182  will slide towards the front end of the base boom  122  and thus get closer to the top front pivot pin  183  which is pivoted at the pivot pin bracket  143  at the base-boom  122 &#39;s front bottom. This movement will make the tilting angle α bigger so the further the unfold, the higher the rear end of the base boom  122  than its front end will be and thus the top boom  126  and middle boom  124  will all be tilted up on their rear end further. This angle α and thus the up tilt of the rear end of the base-boom  122  is used to partially offset the overall bending of the 3-section telescopic boom assembly  120  due to the gravity when fully extended and to keep the top-boom (the platform)  126  staying horizontal as much as possible. 
     Referring now to chassis  140  as shown in  FIG. 12 , the chassis in preferred embodiments has two front wheels  157  that have the driving motor to provide the ‘travel power’ and also two rear wheels  158 . The two front wheels  157  may also steer and when they steer 90 degrees, they will be perpendicular to the rear wheels  158  and in this position when the two front wheels  157  travels, the whole chassis  140  will swing with one of the rear wheels  158  as the ‘swing center’. The chassis  140  has sliding-channels  153  on both sides at the top that allow the bottom sliding-blocks  186  of the scissor links  130  to fit in and slide. The chassis  140  has a middle-link-pivot-bracket  152  bolted at the middle of the top of the chassis  140 . The middle link  133  is pivoted at the bottom to the middle-link-pivot-bracket  152  so the middle link  133  can swing around the middle-link-pivot-bracket  152  when scissor links assembly  130  folds or unfolds. At the same time, since the middle link  133  is pivoted to the bottom front link  135  at the top, this swing and linkage make bottom front link pin  136  and bottom rear link pin  132  slide along channel  153  toward or apart from each other simultaneously through bottom sliding block  186 , thus the center of the scissor links  130  does not change and always stays at the center of middle-link-pivot-bracket  152  on chassis  140 . 
     As shown in  FIG. 12 , the chassis  140  further comprises the counterweight  151  at its front end above and between the two fronts wheels  157  and the counterweight  157  provides the counterbalance when the 3-section telescopic booms  120  extend ‘to the backward’ on the top. It also provides increased traction force for the front wheels  157  when the front wheels drive to travel. The chassis also comprises drawlers  156  located on each side of the front half of the chassis  140  just next to the front wheels. These drawlers  156  hold the battery and hydraulic components inside and also act as the counterbalance when the 3-section telescopic boom assembly  120  extends to the backward on the top. Each drawler is locked by the latch on the top to the chassis  140  and may be opened to gain access to the components inside. The combination of the counterweight  151  and drawlers  156  makes the gravity center of the whole lift much close to the front end of chassis  140  and when the 3 section telescopic boom assembly  120  extends backward, the gravity center will shift to the middle area of the chassis. Two forklift holes  155  are located at the front end of chassis  140  allowing the whole lift can be picked up by forklift when the lift is in the stored position. 
     When the front wheels  157  turn left to the nearly 90 degree and travel, the chassis  140  will then swing around the rear wheel on the left rear side. The 3 section telescopic boom assembly  120  will also then swing together with the chassis  140 . This swing allows the platform to cover more working area on the right when extended. When the front wheels  157  turn right to the nearly 90 degree and travel, the chassis may swing around the rear wheel on the right rear side. The 3 section telescopic boom  120  will then swing together with the chassis  140 . This swing allows the platform to cover more working area on the left when extended. 
     The disclosure above encompasses multiple distinct inventions with independent utility. While each of these inventions has been disclosed in a particular form, the specific embodiments disclosed and illustrated above are not to be considered in a limiting sense as numerous variations are possible. The subject matter of the inventions includes all novel and non-obvious combinations and subcombinations of the various elements, features, functions and/or properties disclosed above and inherent to those skilled in the art pertaining to such inventions. Where the disclosure or subsequently filed claims recite “a” element, “a first” element, or any such equivalent term, the disclosure or claims should be understood to incorporate one or more such elements, neither requiring nor excluding two or more such elements. 
     Applicant(s) reserves the right to submit claims directed to combinations and subcombinations of the disclosed inventions that are believed to be novel and non-obvious. Inventions embodied in other combinations and subcombinations of features, functions, elements and/or properties may be claimed through amendment of those claims or presentation of new claims in the present application or in a related application. Such amended or new claims, whether they are directed to the same invention or a different invention and whether they are different, broader, narrower or equal in scope to the original claims, are to be considered within the subject matter of the inventions described herein.