Patent Publication Number: US-2011061979-A1

Title: Brake mechanism of a hydraulic pallet truck

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a brake mechanism of a hydraulic pallet truck, particularly to one enabling the hydraulic pallet truck to steadily slow down and stop securely. 
     2. Description of the Prior Art 
     Commonly, as shown in  FIG. 1 , a conventional hydraulic pallet truck  1  includes a pressurizing rod  10 , a hydraulic mechanism  11  installed under the pressurizing rod  10 , a connecting base  12  located at one side of the hydraulic mechanism  11 , a supporting base  13  fixed under the hydraulic mechanism  11 , a supporting axis  14  set below the supporting base  13 , and a wheel shaft  15  connected with the supporting axis  14 . In addition, two ends of the wheel shaft  15  are respectively mounted with a wheel  16 . A forked lifting bracket  17  is utilized to carry a pallet that is to be loaded with goods, and a grip  18  is fixed at a free end of the pressurizing rod  10 . With the pressurizing rod  10  reciprocated up and down to pressurize the hydraulic mechanism  11 , the forked lifting bracket  17  can be raised up so as to lift and move the pallet with goods. However, as the conventional hydraulic pallet truck  1  is usually not assembled with a brake, it counts on the strength given by an operator to stop while moving. Unfortunately, it is possible that the hydraulic pallet truck  1  may not be totally stopped should the operator is not powerful enough. Worse, if the hydraulic pallet truck  1  cannot be well controlled by the operator while running on an oblique ground, it may get out of control to accidentally hit people around or collide with something to drop off goods on the pallet. Therefore, the conventional hydraulic pallet truck  1  with no brake is somewhat dangerous during operation. 
     SUMMARY OF THE INVENTION 
     The object of this invention is to offer a brake mechanism employed to steadily slow down and securely stop a hydraulic pallet truck while traveling. 
     Characteristically, the brake mechanism is installed between two wheels of the hydraulic pallet truck. Plural positioning bases are fixed on a wheel shaft and a supporting axis to keep the brake mechanism positioned, respectively provided with plural through holes corresponding to an identical number of nuts. The brake mechanism is provided with a box having plural threaded bolts located on a rear side for being inserted through the through holes of the positioning bases to engage with the nuts, two vertical strips and two pivotal connecting ears correspondingly located on an interior wall, four vertical supporting rods vertically planted inside, a spring mounted around each of the supporting rods, two positioning plates employed to respectively connect two of the supporting rods and resting on the spring, two through holes bored near two ends of each of the positioning plates for the supporting rods to pass through, a through hole bored in each of the positioning plates between the through holes, and two holes bored in a top. A horizontal rod is installed inside the box, provided with two inner through holes, a fastening element employed to penetrate each of the inner through holes and the through hole of each of the positioning plates to keep the horizontal rod positioned on the positioning plates. Two fixing plates are fixed inside the box, respectively provided with a lengthy hole for being inserted by the horizontal rod. A hood is laid on a front vertical side of the box, provided with a sliding groove and a locking groove formed at one end of the sliding groove. A pedal is installed outside the hood, including a connecting rod  440  extended outward from a bottom to pass through the sliding groove of the hood, a pivotal joint extended upward from one end of the connecting rod, a pivotal bolt and nut inserted through the pivotal connecting ears and the pivotal joint, a spring mounted around the pivotal bolt and nut and confined between one of the pivotal connecting ears and the pivotal joint of the connecting rod, a lengthy groove bored in the connecting rod for being inserted by the horizontal rod. Two supporting brackets are correspondingly installed above the box, respectively provided with a threaded rod extended down to insert through said holes of the box to fix with said horizontal rod, a U-shaped groove defined in a top portion, an axial hole bored through each sidewall defining the U-shaped groove. Two connecting plates are respectively fitted in the U-shaped grooves of the supporting brackets, provided with a straight sliding groove, an arc-like sliding groove, an upper axial hole and a lower axial hole bored through two sidewalls. Two pivotal shafts are respectively inserted through the axial holes of the supporting brackets and the upper axial holes of the connecting plates. Two swinging arms and  48  are respectively installed beside the connecting plates, provided with a concave groove and two axial holes bored correspondingly in two side arms to communicate with the concave groove. Two pivotal shafts are respectively inserted through the axial holes and the lower axial holes of the connecting plates. Two wire holes are respectively bored in the swinging arms. One end of a brake wire is orderly inserted through the wire hole of the swinging arm, a spring and the wire hole of the swinging arm, and finally fastened with the swinging arm to keep the spring confined between the swinging arms. Two brake pads are respectively installed outside the connecting plates, provided with an abrasive located at a bottom so as to contact with the wheels, two threaded positioning bars extended inward from a sidewall to respectively pass through the straight sliding groove and the arc-like sliding groove of the connecting plates to engage with a nut so that the brake pads can be fixed beside the connecting plates. A hand brake lever is assembled with a grip and connected with one end of the brake wire. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       This invention is better understood by referring to the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of a conventional hydraulic pallet truck; 
         FIG. 2  is a perspective view of a hydraulic pallet truck installed with a preferred embodiment of a brake mechanism in the present invention; 
         FIG. 3  is a first partial exploded view of the preferred embodiment of a brake mechanism of a hydraulic pallet truck in the present invention; 
         FIG. 4  is a second partial exploded view of the preferred embodiment of a brake mechanism of a hydraulic pallet truck in the present invention; 
         FIG. 5  is a third partial exploded view of the preferred embodiment of a brake mechanism of a hydraulic pallet truck in the present invention; 
         FIG. 6  is a perspective view of the preferred embodiment of a brake mechanism of a hydraulic pallet truck in the present invention; 
         FIG. 7  is a side cross-sectional view of the preferred embodiment of a brake mechanism of a hydraulic pallet truck in the present invention; 
         FIG. 8  is a front cross-sectional view of the preferred embodiment of a brake mechanism of a hydraulic pallet truck in the present invention; 
         FIG. 9  is a perspective view of the preferred embodiment of a brake mechanism of a hydraulic pallet truck in the present invention, showing a pedal being treaded on; 
         FIG. 10  is a side cross-sectional view of the preferred embodiment of a brake mechanism of a hydraulic pallet truck in the present invention, showing the pedal being treaded on; 
         FIG. 11  is a front cross-sectional view of the preferred embodiment of a brake mechanism of a hydraulic pallet truck in the present invention, showing the pedal being treaded on; 
         FIG. 12  is a perspective view of the preferred embodiment of a brake mechanism of a hydraulic pallet truck in the present invention, showing a hand brake lever being pulled; and 
         FIG. 13  is a front cross-sectional view of the preferred embodiment of a brake mechanism of a hydraulic pallet truck in the present invention, showing the hand brake lever being pulled. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIGS. 2˜8  show a preferred embodiment of a brake mechanism  4  of a hydraulic pallet truck in the present invention. As shown in  FIG. 2 , the hydraulic pallet truck  2  includes a pressurizing rod  20 , a grip  21  fixed at a top of the pressurizing rod  20 , a hydraulic mechanism  22  installed under the pressurizing rod  20 , a connecting base  23  located at one side of the hydraulic mechanism  22 , and a supporting base  24  fixed under the hydraulic mechanism  22 . And, as shown in  FIG. 3 , the hydraulic pallet truck  2  is also provided with a supporting axis  25  set below the supporting base  24 . Again, as shown in  FIG. 2 , the hydraulic pallet truck  2  additionally includes a wheel shaft  26  connected with the supporting axis  25 , a wheel  27  installed at two ends of the wheel shaft  26  respectively, a forked lifting bracket  28  located at one side of the connecting base  23  for carrying a pallet used to be loaded with goods, plural positioning bases  3 , the brake mechanism  4  and a hand brake lever  5 . The positioning bases  3  are fixed with the wheel shaft  26  and the supporting axis  25  between the wheels  27 , respectively provided with plural through holes  30  and plural nuts  31  corresponding to the through holes  30 . 
     The brake mechanism  4  is installed between the wheels  27 , provided with a box  40 , two fixing plate  41 , a horizontal rod  42 , a hood  43 , a pedal  44 , two supporting brackets  45 , two connecting plates  46 , two swinging arms  47  and  48 , and two brake pads  49 . 
     The box  40  is provided with plural threaded bolts  400  for passing through the through holes  30  of the positioning bases  3  to engage with the nuts  31 , two vertical strips  401  correspondingly located on an interior wall of a vertical side as shown in  FIG. 4 , two pivotal connecting ears  402  to located between the vertical strips  401  and properly spaced apart, a through hole  403  bored in each of the pivotal connecting ears  402 , four vertical supporting rods  404  planted inside, and a spring  405  mounted around each of the supporting rods  404 . Further, Two positioning plates  406  are employed to respectively connect two of the supporting rods  404 , with two through holes  407  bored near two ends of each of the positioning plates  406  for the supporting rods  404  to pass through. Properly bored between the through holes  407  of each of the positioning plate  406  is a through hole  408 . In addition, a top side of the box  40  is bored with two holes  409  oppositely. 
     Each of the fixing plates  41  is fixed inside the box  40  to contact with one side of the vertical strips  401  respectively, provided with a lengthy hole  410  for the horizontal rod  42  to move therein. 
     The horizontal rod  42  is provided with two inner through holes  420  bored at two preset corresponding locations on an upper side, two outer through holes  421  respectively bored near two ends outside the inner through holes  420 , a fastening element  422  employed to penetrate each of the inner through holes  420  and the through hole  408  of each of the positioning plates  406  to keep the horizontal rod  42  positioned on the positioning plates  406 , and two pairs of nuts  423  respectively located thereon and thereunder to correspond to the outer through holes  421 . 
     The hood  43  is laid on a front side of the box  40 , provided with an L-shaped sliding groove  430 , and a locking groove  431  extended upward from a right portion of the sliding groove  430 . 
     The pedal  44  is installed outside the hood  43 , provided with a connecting rod  440  extended outward from the bottom to pass through the sliding groove  430  of the hood  43 , a lengthy groove  441  bored in the connecting rod  440  for being inserted by the horizontal rod  42 , a pivotal joint  442  extended upward from one end of the connecting rod  440  and having a through hole  443  bored in the pivotal joint  442 . In addition, a pivotal bolt and nut  444  is employed to pass through the through holes  403  of the pivotal connecting ears  402  and the through hole  443 , mounted with a spring  445  located between one of the connecting ears  402  and the pivotal joint  442 . 
     Two supporting brackets  45  shown in  FIG. 3  are installed above the box  40 , respectively provided with a threaded rod  450  extended down, as shown in  FIG. 5 , through the holes  409  of the box  40 , an U-shaped groove  451  defined in a top portion, an axial hole  452  bored through each sidewall defining the U-shaped groove  451 , and two pivotal shafts  453  extending through the two axial holes  452 . 
     Two connecting plates  46  are respectively fitted in the U-shaped groove  451  of the supporting brackets  45 , provided with a straight sliding groove  460 , an arc-like sliding groove  461 , an upper axial hole  462  and a lower axial hole  463  bored through two sidewalls. The pivotal shafts  453  are used to pass through the axial holes  452  of the supporting brackets  45  and the upper axial holes  462 . 
     Two swinging arms  47  and  48  are respectively provided with a concave groove  470 ( 480 ), and two axial holes  471 ( 481 ) bored correspondingly in two side arms to communicate with the concave groove  470 ( 480 ). The swinging arm  47  is additionally provided with a wire hole  472  for a brake wire  473  to pass through, and a spring  474  mounted around one end of the brake wire  473 . The swinging arm  48  is additionally provided with a connecting piece  482  shaped as a reverse L, a wire hole  483  bored in the top side of the connecting block  482  for the brake wire  473  to pass through, a through hole  484  bored in another side of the connecting piece  482  for a screw  485  to pass through, and a wire hole  486  transversely bored through the screw  485  for the brake wire  473  to pass through and get fixed thereof. Furthermore, two pivotal shafts  475  and  487  are inserted through the axial holes  471  and  481  and the lower axial holes  463  of the connecting plates  46  respectively. 
     Two brake pads  49  are respectively installed outside the connecting plates  46 , provided with an abrasive  490  located at the bottom, two threaded positioning bars  491  extended inward from a sidewall of each of said brake pads  49 , and two nuts  492  to be engaged with the threaded positioning bars  491 . 
     Moreover, a hand brake lever  5  is assembled with the grip  21  and connected with one end of the brake wire  473 . 
     In using, as shown in  FIGS. 9˜11 , the hydraulic pallet truck  2  can be stopped by treading on the pedal  44  of the brake mechanism  4  while running. As soon as the pedal is pressed down, the connecting rod  440  of the pedal  44  is to swing down round the pivotal bolt and nut  444 , and the horizontal rod  42  is as well forced to descend, enabling the positioning plates  406  to move downward along the supporting rods  404 . By the time, the spring  445  is elastically contracted. The supporting brackets  45  and the connecting plates  46  are also moved down as the horizontal rod  42  is declining. So are the brake pads  49  compelled to move down to enable the abrasives  490  to contact with the wheels  27 . The wheels  27  are then to be stopped running. Therefore, the hydraulic pallet truck  2  is quickly stopped still. If the hydraulic pallet truck  2  is continued to be parked, an operator just needs to push the pedal  44  to move aside after treading on it, so that the connecting rod  440  is positioned in the locking groove  431  of the hood  43  to keep the spring  445  continuously contracted, forcing the abrasives  490  to tightly contact with the wheels  27  to keep them from running. When the hydraulic pallet truck  2  is to be released from being braked, it only needs to tread on the pedal  44  and push it into the sliding groove  430 . By means of elasticity of the spring  445 , the horizontal rod  42 , the pedal  44  and the supporting brackets  45  are to be moved upward to their original positions. The connecting plates  46  and the brake pads  49  are simultaneously driven by supporting brackets  45  to move up, keeping the abrasives  490  from contacting with the wheels  27 . In addition, as shown in  FIGS. 12˜13 , an operator can utilize the hand brake lever  5  by hand to tightly pull the brake wire  473  for stopping the hydraulic pallet truck  2 . As the brake wire  473  is pulled up, the swinging arms  47  and  48  will move close to each other to compress the spring  474 . Being driven by the swinging arms  47  and  48 , with the pivotal shafts  453  of the supporting brackets  45  functioning as axis, the bottoms of the connecting plates  46  are to swing up inwardly and the tops of the connecting plates  46  are to swing down outwardly. By the time, the brake pads  49  are to be moved down outwardly so as to enable the abrasives  490  to rest on the wheels  27  to create friction to slow down the hydraulic pallet truck  2 . Assembled with either the pedal  44  operated by a foot or the hand brake lever  5  pulled by hand, the hydraulic pallet truck  2  can therefore travel securely. 
     It is to be noticed that the interval between the abrasives  490  and the wheels  27  is adjustable. That is, twisting the threaded rods  450  of the supporting brackets  45  along the nuts  423  located above and under the horizontal rod  42  can enhance or lessen the length of the threaded rods  450  extending above the box  40 , so enabling the interval between the abrasives  490  and the wheels  27  lengthened or shortened as well. And, by means of the straight groove  460  and the arc-like groove  461  of the connecting plates  46 , the angle of the brake pads  49  can adjusted to maximally contact with the wheels  270  to achieve a maximum braking effect. 
     While the preferred embodiment of the invention has been described above, it will be recognized and understood that various modifications may be made therein and the appended claims are intended to cover all such modifications that may fall within the spirit and scope of the invention.