Patent Publication Number: US-8978540-B2

Title: Cylinder

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to driving mechanisms, and more particularly, to a clamping cylinder. 
     2. Description of Related Art 
     A cylinder may be used to clamp materials. Many cylinders may include a cylinder block defining a receiving chamber, a piston and a push rod received in the receiving chamber. The cylinder block may define two openings at opposite ends communicating with the receiving chamber. The piston may be movably received in the receiving chamber, a first end of the push rod may be fixed to the piston, and a second end of the push rod may extend out of the cylinder body via one opening. Airborne contaminants, such as dust particles, in a production facility may abrade and jam the piston and the push rod, and shorten the life of the cylinder. Moreover, the volume of the cylinder may be relatively large, and a significant amount of space may be needed to enable the cylinder to work. 
     Therefore, there is room for improvement in the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The components in the drawings are not necessarily drawn to scale, the emphasis instead placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an isometric view of an embodiment of an assembled cylinder. 
         FIG. 2  is an exploded, isometric view of the cylinder of  FIG. 1 . 
         FIG. 3  is similar to  FIG. 2 , but viewed from another perspective. 
         FIG. 4  is a cross-sectional view of the cylinder of  FIG. 1 , taken along line IV-IV. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , an embodiment of a cylinder  100  includes a mounting plate  10 , a cylinder block  20 , a piston  30 , and a pushrod assembly  40 . The cylinder block  20  includes a main body  21  defining a receiving chamber  212 . The mounting plate  10  is mounted on a side of the cylinder block  20 , the piston  30  is slidably installed in the receiving chamber  212 , the pushrod assembly  40  is movably mounted in the receiving chamber  212  and an end of the pushrod assembly  40  extends perpendicularly out of the cylinder block  20 . The pushrod assembly  40  is capable of being driven by the piston  30  and moving in or out of the cylinder  100  to clamp or release a workpiece. 
     The mounting plate  10  is a substantially rectangular and defines a plurality of mounting holes (not shown) for mounting the cylinder block  20 . 
     The cylinder block  20  includes a first cover  23 , a second cover  25 , and two sealing assemblies  27 . The first cover  23  and the second cover  25  are together and located at a side of the main body  21 . The two sealing assembles  27  are mounted on opposite ends of the main body  21  to seal the receiving chamber  212 . 
     Also referring to  FIGS. 3 and 4 , the main body  21  is a cuboid hollow structure comprising peripheral walls  211  in a rectangle housing shape. The receiving chamber  212  extends a length of the main body  21 . The main body  21  further defines two openings  213  interconnecting with the receiving chamber  212  at opposite ends. The peripheral walls  211  define two vents  215  adjacent to the two openings  213 , a mounting recess  217 , and a through hole  219  at opposite sides. The two vents  215  are located at one side of the peripheral walls  211  and are interconnected with the receiving chamber  212 . The mounting recess  217  is located between the two vents  215 . The peripheral walls  211  further include a mounting surface  2171  corresponding to the mounting recess  217 . The mounting surface  2171  defines a fixing hole  2173  interconnecting with the receiving chamber  212  in the mounting recess  217 . In the embodiment, the receiving chamber  212  is a hollow cylinder. The two openings  213  are substantially circular, and each of the two openings  213  has a diameter greater than a diameter of the receiving chamber  212 . The peripheral walls  211  further include a first joint portion  2131 , and a second joint portion  2133  corresponding to each of the two openings  213 . The first joint portion  2131  and the second joint portion  2133  are positioned side by side and cooperatively form a stepped annular structure. The first joint portion  2131  is at an end of the receiving chamber  212 , and the second joint portion  2133  is separated from the receiving chamber  212  by the first joint portion  2131 . In the embodiment, the fixing hole  2173  and the through hole  219  are substantially rectangular. 
     The first cover  23  and the second cover  25  are rectangular and function as one unit. The first cover  23  is located on the mounting recess  217  and seals the fixing hole  2173 . The second cover  25  includes a position portion  251  located on an underside of the second cover  25  facing the fixing hole  2173 . The second cover  25  defines a containing chamber  2511  at a second side opposite to a first side. The second cover  25  further defines a hole  2513  in the position portion  251  communicating with the containing chamber  2511 . The position portion  251  is capable of engaging in the fixing hole  2173 . 
     The two sealing assemblies  27  are mounted in the two openings  213 . Each of the two sealing assembly  27  includes a sealing member  271 , a blocking ring  273 , an internal circlip  275 , and a buffering member  277 . The sealing member  271  is fixed to the first joint portion  2131  in each of the two openings  213 . The sealing member  271  is substantially a round disk. The sealing member  271  defines a sealing groove  2711  on a periphery, and includes a post  2713  in the middle of an end. The post  2713  and the periphery of the sealing member  271  cooperatively define an annular receiving space  2715 . The blocking ring  273  is a ring sleeved on the sealing member  271  and engaged in the sealing groove  2711 . The buffering member  277  is a split rubber ring which is press fit in the receiving space  2715 . 
     The piston  30  is received in the receiving chamber  212  and is capable of sliding between the two openings  213  of the cylinder block  20 . The piston  30  includes a base body  31 , and two sealing rings  33 . The base body  31  is substantially cylindrical in shape and includes a side surface  311 , a first end surface  313 , and a second end surface  315 . The base body  31  further defines two annular grooves  316  on the side surface  311 , adjacent to the first and second surfaces  313 ,  315 ; and a through groove  317  located between the two annular grooves  316 . The through groove  317  has a shape of a thin oval. The base body  31  further includes a resisting surface  318  in the side surface  311  corresponding to the through hole  219 . In the embodiment, the resisting surface  318  has an inclined surface, and distances between the resisting surface  318  and an inner surface of the peripheral walls  211  increase from the first end surface  313  toward the second end surface  315  of the piston  30 . The two sealing rings  33  are mounted in the two annular grooves  316  to provide a hermetic seal for the piston  30 . 
     The pushrod assembly  40  is slidably mounted in the through groove  317  of the piston  30 . The pushrod assembly  40  includes a push block  41 , a sleeve  43 , a sliding rod  45 , and a resilient member  47 . The push block  41  is substantially a solid cuboid block and slidably engages in the through hole  219 . The push block  41  includes an inclined surface  411  at one end matching a profile of the resisting surface  318  of the piston  30 . The sleeve  43  extends through the through groove  317  and is cylindrical around a receiving hole  431 . When the piston  30  slides along the receiving chamber  212 , the sleeve  43  is always retained in the through groove  317 . The sleeve  43  further defines an opening  433  and a bottom hole  435 . The sleeve  43  includes a first resisting portion  4331  and a second resisting portion  4351 . The opening  433  and the bottom hole  435  are located at opposite ends of the sleeve  43  and communicate with the receiving hole  431 . The first resisting portion  4331  surrounds the opening  433 , and the second resisting portion  4351  surrounds the bottom hole  435 . The first resisting portion  4331  is an external flange with a diameter greater than a diameter of the sleeve  43 . The second resisting portion  4351  is an internal flange with a diameter smaller than an interior diameter of the sleeve  43 . The sliding rod  45  slidably extends through the bottom hole  435 . The sliding rod  45  includes a head portion  451  received in the receiving hole  431  of the sleeve  43 , and a rod portion  453  opposite to the head portion  451 . The rod portion  453  is partially received in the receiving hole  431 . One end of the rod portion  453  extends out of the sleeve  43  and is fixed to the inclined surface  411  of the push block  41 . The resilient member  47  is sleeved on the rod portion  453  of the sliding rod  45  and positioned between the head portion  451  and the second resisting portion  4351 . 
     In assembly, the piston  30  is received in the receiving chamber  212  to divide the receiving chamber  212  into two parts (not labeled), the resisting surface  318  facing the through hole  219 . One blocking ring  273  is received into the sealing groove  2711  of one of the two sealing members  271 . One buffering member  277  is sleeved on the post  2713  and pressed into the receiving space  2715 . One sealing member  271  engages in one of the two openings  213  with the post  2713  facing the receiving chamber  212 . The periphery of the blocking ring  273  resists the first joint portion  2131 , the internal circlip  275  is compressed to be installed against the sealing member  271  and the second joint portion  2133 , such that one of the two sealing assemblies  27  is assembled and held captive in the main body  21 . Similarly, another one of the two sealing assemblies  27  is assembled to the main body  21  with another one of the two openings  213 . 
     The second cover  25  is fixed to the mounting surface  2171  of the mounting recess  217  with the position potion  251  extending into the fixing hole  2173 . The resilient member  47  is sleeved on the rod portion  453 , and the sliding rod  45  extends into the receiving hole  431  of the sleeve  43 . The sleeve  43  extends into the hole  2513  of the second cover  25 , and into the through groove  317  of the piston  30 . The first resisting portion  4331  is received in the containing chamber  2511  to prevent detachment of the sleeve  43  from the second cover  25 . The head portion  451  of the sliding rod  45  is pressed towards the bottom hole  435 . One end of the sliding rod  45  extends into the through groove  317 . The push block  41  is slidably mounted in the through hole  219  with the inclined surface  411  facing the resisting surface  318  of the piston  30 . The end of the sliding rod  45  furthest from the head portion  451  is fixed to the inclined surface  411 . The head portion  451  is released, so that the resilient member  47  resists the head portion  451  and the second resisting portion  4351  to enable the sliding rod  45  to pull the push block  41  towards the piston  30 . The first cover  23  is fixed to the second cover  25  to entirely seal the cylinder block  20 . The assembly of the cylinder  100  is completed. 
     When in use, the two vents  215  communicate with two gas supplies (not shown) for supplying pressurized gas to the receiving chamber  212 . When there is more air pressure upon the first end surface  313 , the piston  30  is pushed toward one of the two openings  213 . The resisting surface  318  moves along the receiving chamber  212 . As the distance between the resisting surface  318  and the inner surface of the peripheral walls  211  decreases, the push block  41  is moved outwardly from the cylinder block  20  via the through hole  219 . The push block  41  then has a clearance for clamping a workpiece. In reverse, when there is less air pressure upon the first surface  313 , the piston  30  moves towards the first end surface  313  and the resilient member  47  pulls the push block  41  back. At the same time, the resilient member  47  is released and pulls the sliding rod  45  toward the second cover  25 . The sliding rod  45  and the air pressure together pull the push block  41  inwards, such that the push block  41  moves inwards via the through hole  219  and thereby releases the workpiece. 
     Since the cylinder block  20  is entirely sealed and the push block  41  communicates with the outside only via the through hole  219 , dust particles have very little opportunity of entering into the receiving chamber  212  of the cylinder block  20 . Therefore, incidents of jamming problems caused by ingress of foreign matters and particles may decrease sharply. As the piston  30  moves between the two openings  213 , and the push block  41  moves perpendicularly to the piston  30 , the fitting and working space required for the cylinder  100  may be decreased. Moreover, since the piston  30  pushes on the push block  41  by means of the resisting surface  318  to resist the inclined surface  41 , it may be almost impossible for the pushrod assembly  40  to be broken. 
     The distance between the resisting surface  318  and the inner surface of the peripheral walls  211  may be decreased from the first end surface  313  towards the second end surface  315 . In other words, an angle of inclination from the surface  318  to the peripheral walls  211  may be decreased. In other embodiments, the resisting surface  318  may have other shapes, such as a curved surface with the distance between the curved surface and the inner surface of the peripheral walls  211  increasing from the first end surface  313  towards the second end surface  315 . The two sealing assemblies  27  may be omitted if the cylinder block  20  is formed integrally, with both ends blind. 
     Finally, while various embodiments have been described and illustrated, the disclosure is not to be construed as being restricted thereto. Various modifications can be made to the embodiments by those skilled in the art without departing from the true spirit and scope of the disclosure as defined by the appended claims.