Patent Publication Number: US-8973360-B2

Title: Pressure cylinder having a hidden loop design

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a pressure cylinder and more particularly, to a pressure cylinder, which has a hidden loop design. 
     2. Description of the Related Art 
     The so-called pressure cylinder is a combination of an air cylinder and a hydraulic cylinder, which mainly uses a piston rod of the air cylinder to compress a hydraulic fluid in giving a pressure to a piston rod of the hydraulic cylinder, thereby enhancing the output force of the piston rod of the hydraulic cylinder. 
     However, in all conventional pressure cylinder designs, the applied compressed gas is flowing through a loop formed of external pipelines. After a long use, the external pipelines may be oxidized and deteriorated. Therefore, the pipelines must be regularly replaced. Further, the connectors connecting the pipelines may be loosened easily, causing a gas leak. All these problems may lead to machine failure, or even industrial accidents. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a pressure cylinder, which has a hidden loop design for guiding a compressed gas without any pipelines and connectors, avoiding pipeline deterioration or connector loosening problems. 
     To achieve this and other objects of the present invention, a pressure cylinder comprises a cylinder body, a pressure-boosting member set, and an actuation member set. The cylinder body comprises a first air chamber, a second air chamber, an oil accumulation chamber disposed between the first air chamber and the second air chamber, a first air outlet transversely disposed in communication with the first air chamber, a second air outlet transversely disposed in communication with the second air chamber, a first air inlet and a second air inlet transversely disposed in a parallel manner between the first air outlet and the second air outlet, a first air passage disposed in communication with the first air inlet and the first air outlet, and a second air passage disposed in communication with the second air inlet and the second air outlet. The pressure-boosting member set comprises a first piston set in the first air chamber of the cylinder body and movable axially relative to the cylinder body by an applied compressed gas, and a pressure-boosting piston rod and movable axially relative to said cylinder body by said first piston. The pressure-boosting piston rod has one end thereof connected to the first piston and an opposite end thereof inserted into the oil accumulation chamber of the cylinder body. The actuation member set comprises a second piston and an actuation piston rod. The second piston is set in the oil accumulation chamber of the cylinder body, defining therein an axially extending pressure-boosting chamber in communication with the oil accumulation chamber for receiving the pressure-boosting piston rod of the pressure-boosting member set. The actuation piston rod is movable axially relative to the cylinder body by the second piston, having one end thereof connected to the second piston and suspending between the second air chamber and the oil accumulation chamber, and an opposite end thereof extending out of the cylinder body. 
     Thus, the applied compressed gas can flow through the first air outlet, the first air passage and an internal loop being formed of the first air outlet into the first air chamber to move the pressure-boosting piston rod into the pressure-boosting chamber in compressing the hydraulic fluid in the pressure-boosting chamber to move the actuation piston rod of the actuation member set. Similarly, the compressed gas can be forced to flow through the second air outlet, the second air passage and another internal loop being formed of the second air outlet into the second air chamber to return the pressure-boosting member set and the actuation member set. 
     Other advantages and features of the present invention will be fully understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference signs denote like components of structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plain view of a pressure cylinder in accordance with the present invention. 
         FIG. 2  is a sectional view taken along line  2 - 2  of  FIG. 1 . 
         FIG. 3  is a sectional view taken along line  3 - 3  of  FIG. 1 . 
         FIG. 4  is a schematic sectional view of the present invention, illustrating a pressure-boosting stroke of the pressure-boosting member set and the actuation member set. 
         FIG. 5  is a schematic sectional view of the present invention, illustrating a return stroke of the pressure-boosting member set and the actuation member set. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1 and 2 , a pressure cylinder  10  in accordance with the present invention is shown. The pressure cylinder  10  comprises a cylinder body  20 , a pressure-boosting member set  30 , and an actuation member set  40 . 
     Referring to  FIG. 3 , the cylinder body  20  comprises a first air chamber  202  defined in an upper part thereof, a second air chamber  204  defined in a lower part thereof, an oil accumulation chamber  21  disposed between the first air chamber  202  and the second air chamber  204 , a first air outlet  22  transversely disposed at a top side thereof in communication with the first air chamber  202 , a second air outlet  23  transversely disposed at a bottom side thereof in communication with the second air chamber  204 , a first air inlet  24  and a second air inlet  25  transversely disposed in a parallel manner between the first air outlet  22  and the second air outlet  23 , a first air passage  26  vertically disposed in communication with the first air inlet  24  and the first air outlet  22 , a second air passage  27  vertically disposed in communication with the second air inlet  25  and the second air outlet  23  at one side relative to the second air inlet  25 , and a third air passage  28  vertically disposed in communication with the second air inlet  25  and the first air chamber  202  at opposite side relative to the second air inlet  25 . Further, an electromagnetic valve  50  is mounted at one side of the cylinder body  20  and connected to the first air inlet  24  and the second air inlet  25  for controlling the flowing direction of a compressed gas. Further, an oil immersion lens  29  is mounted at an opposite side of the cylinder body  20  corresponding to the oil accumulation chamber  21  for observing the condition of the accumulated hydraulic fluid in the oil accumulation chamber  21 . 
     The pressure-boosting member set  30  comprises a first piston  32  and a pressure-boosting piston rod  34 . The first piston  32  is set in the first air chamber  202  of the cylinder body  20 , and movable along the axial direction of the cylinder body  20  by the pressure of a compressed gas. The pressure-boosting piston rod  34  has its one end connected to the first piston  32 , and its other end inserted into the oil accumulation chamber  21  of the cylinder body  20  and movable along the axial direction of the cylinder body  20  by the first piston  32 . 
     The actuation member set  40  comprises a second piston  42  and an actuation piston rod  44 . The second piston  42  is set in the oil accumulation chamber  21  of the cylinder body  20 , defining therein an axially extending pressure-boosting chamber  46  in communication with the oil accumulation chamber  21  for receiving the pressure-boosting piston rod  34  of the pressure-boosting member set  30 . The actuation piston rod  44  has its one end connected to the second piston  42  and disposed in the second air chamber  204  and its other end extending out of the cylinder body  20 , and is movable along the axial direction of the cylinder body  20  by the second piston  42 . 
     When guiding an external compressed gas through the first air inlet  24  of the cylinder body  20  into the first air chamber  202  via the first air outlet  22 , the first piston  32  of the pressure-boosting member set  30  will be forced downwards to move the pressure-boosting piston rod  34  into the pressure-boosting chamber  46  of the second piston  42  of the actuation member set  40 , thereby compressing the hydraulic fluid in the pressure-boosting chamber  46  to move the actuation piston rod  44  of the actuation member set  40 , as shown in  FIG. 4 . On the contrary, when the flowing direction of the applied compressed gas is changed subject to the control of the electromagnetic valve  50 , i.e., the compressed gas is forced to flow through the second air inlet  25  of the cylinder body  20  toward the second air passage  27  and the second air outlet  23  into the second air chamber  204  and also toward the third air passage  28  into the first air chamber  202 , the first piston  32  of the pressure-boosting member set  30  and the actuation piston rod  44  of the actuation member set  40  are simultaneously forced by the pressure of the compressed gas to move upwardly to their respective former positions, as shown in  FIG. 5 . 
     Based on the aforesaid arrangement, either during the pressure-boosting stroke or return stroke of the pressure-boosting member set and the actuation member set, the compressed gas is flowing in the hidden loop inside the cylinder body. Thus, the invention does not require any extra pipelines or connectors, avoiding pipeline deterioration or connector loosening problems. 
     Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.