Patent Publication Number: US-6699002-B2

Title: Telescopic lifting vehicle

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a telescopic lifting vehicle. 
     For many years, telescopic lifting vehicles have been constructed with a central telescopic arm, at the two sides whereof are mounted at one side the driver&#39;s cab and at the other the engine (as described, for example, in the Patent DE 2 739 537). 
     The evolution of telescopic lifts has then led, over the years, to several improvements of their constructive structure, in order to improve on one hand the stability of the vehicle when lifting loads, on the other the visibility of the operator sitting in the cab. 
     In fact, whilst several years ago the telescopic arm was pivotally engaged to the frame of the vehicle in a rear raised position, and developed to a height corresponding to, if not even greater than, that of the cab window, currently, as described for example in U.S. Pat. No. 5,199,861, the arm is positioned substantially below the cab window, in an appropriate housing obtained on the frame, between the base of the cab and the engine of the vehicle. 
     In accordance with the art illustrated in U.S. Pat. No. 5,199,861, to enable keeping the telescopic arm below the cab, its lifting cylinder is positioned laterally between it and the cab. In this way, however, drawbacks are encountered in terms of lateral size. 
     Another characteristic that hampers the lowered positioning of the telescopic arm, in currently used lifting vehicles, consists of the shape of the frontal stabilisers of the vehicle, and in particular in the shape of the frame whereto the stabiliser feet are associated. 
     Said frame has a latching portion fastened to the frame of the vehicle, and a support portion bearing the feet. In known manners, the latching portion has a substantially rectangular coupling surface able to be fastened to the front portion of the vehicle frame, below the telescopic arm (FIGS.  5  through  7 ). 
     The presence of the latching portion thus constitutes a limit for the lowering of the arm relative to the vehicle. 
     SUMMARY OF THE INVENTION 
     In this situation the technical task constituting the basis for the present invention is to obtain a telescopic lifting vehicle that overcomes the aforementioned drawbacks. 
     In particular a technical task of the present invention is to obtain a telescopic lifting vehicle that assures an excellent visibility to the operator sitting in the cab, whilst keeping the centre of gravity of the vehicle lower than in traditional vehicles. 
     The specified technical task and the indicated aims are substantially achieved by a telescopic lifting vehicle, as described in the accompanying claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further features and advantages of the invention shall become more readily apparent from the detailed description that follows of some preferred, but not exclusive, embodiments of a telescopic lifting vehicle, illustrated in the accompanying drawings, in which: 
     FIG. 1 shows a schematic lateral view, with some parts removed and others shown in see-through fashion, of a telescopic lifting vehicle according to the present invention; 
     FIG. 2 shows a schematic plan view, with some parts removed and others shown in see-through fashion, of the telescopic lifting vehicle of FIG. 1; 
     FIG. 3 shows a detail of the vehicle of FIG. 2; 
     FIG. 4 shows a front sectioned view of the detail of FIG. 3 according to trace IV—IV; 
     FIG. 5 shows a front schematic view of a detail of a telescopic lifting vehicle according to the prior art; 
     FIG. 6 shows a schematic partial plan view of the detail of FIG. 5; 
     FIG. 7 shows a schematic partial lateral view of the detail of FIG. 5; 
     FIG. 8 shows a front view of the detail of FIG. 5 according to the present invention; 
     FIG. 9 shows a schematic partial plan view of the detail of FIG. 8; 
     FIG. 10 shows a schematic partial lateral view of the detail of FIG. 8; 
     FIG. 11 shows an axonometric three-quarters view of the frame of a telescopic lifting vehicle according to the present invention; 
     FIG. 12 shows a plan view of the frame of FIG. 11; 
     FIG. 13 shows an axonometric three-quarters view of a telescopic lifting vehicle according to the present invention; 
     FIG. 14 shows a plan view of the vehicle of FIG. 13 with some parts removed and others shown in see-through fashion; 
     FIG. 15 shows a lateral elevation view of FIG. 13 with some parts removed and others shown in see-through fashion; 
     FIG. 16 shows a lateral elevation view of  15  with the telescopic arm in the raised position; 
     FIG. 17 shows a front view of the vehicle of FIG. 15 with the lifting arm sectioned according to trace XVII—XVII of FIG. 15; 
     FIG. 18 shows a lateral elevation view of vehicle of FIG. 13 with the telescopic arm in raised position; 
     FIG. 19 shows a bottom view of the vehicle of FIG. 13; 
     FIG. 20 shows a front view of the vehicle of FIG. 15 with the stabiliser feet in the two possible positions; 
     FIG. 21 shows a lateral elevation view of the detail of the stabilisers of the vehicle FIG.  15 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to the aforementioned figures, the reference number  1  globally indicates a telescopic lifting vehicle, according to the present invention. 
     The lifting vehicle  1  is constituted by a support frame  2  having a central longitudinal axis of development, at the sides whereof are mounted on one side a control cab  3 , on the other an engine  4  for powering the vehicle  1 . 
     On the frame  2  is also mounted a telescopic arm  5  having its base portion  6  pivotally engaged to a rear portion of the frame  2  itself, according to a horizontal axis perpendicular to the longitudinal axis. The arm  5  further has an operative extremity  7  able to be associated to an operative tool  8 , such as a lifting fork as shown in the accompanying figures. 
     The vehicle  1  is further provided with a front axle  9  and with a rear axle  10  provided with wheels. Between the engine  4 , which in the preferred embodiment has its own axis positioned horizontally and inclined towards the front part of the longitudinal axis of the vehicle  1 , and each of the two axles  9 ,  10 , are further connected, in this order, a transmission  11 , a transfer case  12  and a drive shaft  13  developing horizontally under the frame  2 . 
     As shown for example in FIGS. 1,  15 ,  16  and  19 , the drive shaft  13  is formed by two portions  13   a  (front portion) and  13   b  (rear portion) both connected to the transfer case  12 . 
     The frame  2 , between the engine  4  and the cab  3 , has a housing  14  open superiorly and developing over the entire length of the vehicle  1  along the longitudinal central axis, inside which can be inserted, at least partially, the telescopic arm  5 , when it is in non operative position. 
     The arm  5  is movable between the non operative position and an operative position in which it is inclined upwards (FIGS. 16 and 18) through a lifting cylinder  15  which has a first end  16  pivotally engaged to the frame  2  and a second end  17  pivotally engaged to the telescopic arm  5 , and which is positioned below the telescopic arm  5  itself. 
     In regard to the frame  2 , it has a vertical opening  18  in correspondence with at least a part of the housing  14 , opening  18  in which the lifting cylinder  15  is inserted when the telescopic arm  5  is recessed in the housing  14 . In this circumstance the lifting cylinder  15  is located substantially below the frame  2 . 
     As is also shown in the accompanying figures, the lifting cylinder  15  is preferably positioned in front of the rear axle  10 , behind the transfer case  12 , above the drive shaft  13  and below the frame  2 . 
     In the preferred embodiment the frame  2  is constituted by two lateral bodies  19 ,  20 , each defining a lateral wall of the housing  14 , and identifiable as a first body  19  positioned on the side of the cab  3  and a second body  20  positioned on the side of the engine  4 , connected to a plurality of brackets  21  having horizontal development, transverse to the longitudinal axis of the vehicle  1 , and positioned below the housing  14 . 
     From the first body  19  develop some shelves  22  for supporting the cab  3 , whilst the engine  4  is connected directly to the second body  20 . 
     Each axle  9 ,  10  is supported by a pair of brackets  21 , positioned one in front and one behind it. 
     Moreover, the first end  16  of the lifting cylinder  15  is pivotally engaged to one of the brackets  21  supporting the rear axle  10 , specifically to the front bracket  23 . 
     The telescopic lifting vehicle  1  further comprises means  24  for leveling the operative tool  8  to maintain the operative tool  8  parallel to itself during the motions of the arm  5 , means which are constituted by a leveling cylinder  25  fastened to the operative end  7  of the arm  5 , and by a compensating cylinder  26  hydraulically connected to the leveling cylinder  25 . 
     The compensation cylinder  26  has a primary end  27  pivotally engaged to the frame  2  and a secondary end  28  pivotally engaged to the telescopic arm  5 , and it is positioned parallel and horizontally coplanar to the lifting cylinder  15  below the telescopic arm  5 , in such a way as to be also inserted in the opening  18  when the arm  5  is inserted in the housing  14 . 
     In particular, the compensating cylinder  26  has a length equal to that of the lifting cylinder  15 , so that the first end  16  of the lifting cylinder  15  and the primary end  27  of the compensating cylinder  26  are pivotally engaged to the frame  2  by means of a single first pivot pin  29 , and, similarly, in such a way that the second end  17  of the lifting cylinder  15  and the secondary end  28  of the compensating cylinder are pivotally engaged to the frame  2  by means of a single second pivot pin  30 . 
     Each pivot pin  29 ,  30  is inserted through two forks set side by side, fastened to the frame  2 , having a central tine in common, and destined one to the lifting cylinder  15  and one to the compensating cylinder  26 . 
     Additionally, there can also be a connecting element  31  of the jacket  32  of the compensating cylinder  26  to the jacket  33  of the lifting cylinder  15  in order to sustain the compensating cylinder  26  when the telescopic arm  5  is raised, preventing the occurrence of deformations to the compensating cylinder  26  itself, due to the disparity between the length and the diameter of the cylinder when it is extended, and at the high pressures that can be created therein, under certain load conditions. 
     The telescopic lifting vehicle  1  is also provided with stabilisation means  34  mounted anteriorly to the frame  2 , and constituted by a structure  35  bearing two legs  36  each provided with a stabiliser foot  37 . The structure  35  comprises a portion  38  for latching to the frame  2  and a portion  39  for supporting the legs  36  which extends transversely relative to the vehicle  1 . As shown in FIG. 8, the support portion  39  has an arcuate shape going partially around the telescopic arm  5 . 
     The legs  36  are positioned at the lateral ends of the support portion  39  and have each an inner end  40  pivotally engaged to the support portion  39 , and an outer end  41  bearing the stabiliser foot  37 . 
     Each leg  36  can be actuated between a locked position in which the foot  37  is set down on the ground, and a manoeuvring position in which the foot  37  is raised off the ground. 
     The latching portion  38  is associated to a front portion  42  of the frame  2  whilst the supporting portion  39  is integrally connected with the latching portion  38  in its own intermediate portion. 
     When the telescopic arm  5  is inserted in the housing  14 , the supporting portion  39  is below it. 
     The latching portion  38  instead is associated to the frame  2  at the two sides of the housing  14 , and has, in correspondence with the related areas of coupling to the frame  2 , a U shape with a side of the U fastened to the first lateral body  19  and the other side of the U fastened to the second lateral body  20 . 
     The latching portion  38  also has a second surface  43  able to be associated to the frame  2  below its front portion  42  (FIG.  21 ). 
     As shown in FIGS. 20 and 21, when the feet  37  are in the manoeuvring position and the arm  5  is inserted in the housing  14 , the arm  5  is positioned at a height not exceeding that of the stabiliser feet  37 . 
     The actuation of each leg  36  is performed by a hydraulic actuating cylinder  44  having its jacket and piston associated one below the telescopic arm  5  to the support portion  39  of the structure  35 , the other one to the leg  36 . The hydraulic cylinders are fed by means of a feed valve  45  associated to each cylinder  44  in correspondence with its area close to the leg  36 , in such a way as not to be a hindrance for the arm  5  (FIG.  8 ). 
     The operation of the vehicle  1  of the present invention takes place in ways similar to those of traditional telescopic lifters, and directly deducible from the description made heretofore of the vehicle  1  itself. 
     The present invention achieves important advantages, since, for the same free height from the ground and the same dimensions of the arm and of the cab, a vehicle in accordance with the present invention has a lower centre of gravity than do vehicles in accordance with the prior art, whilst also assuring an excellent visibility to the operator sitting in the cab. 
     Comparing prior art vehicles, shown in FIG. 5, with the embodiment of FIG. 8, it is evident that in the present invention the arm (and thus the centre of gravity of the vehicle) is considerably lower. 
     It should also be noted that the present invention is also relatively easy to realise and that the cost connected to implementing the invention is not very high. 
     The invention thus conceived can be subject to numerous modifications and variations, without thereby departing from the scope of the inventive concept that characterises it. 
     All components can be replaced by other technically equivalent elements and in practice all materials used, as well as the shapes and dimensions of the various components, can be any depending on requirements.