Abstract:
An exemplary manipulator includes arms, an inlet conduit, and sealing members. The arms are rotatably joined. The inlet conduit extends into one of the arms and non-combustible gas is introduced into the arms via the inlet conduit. The sealing members are disposed where two corresponding of the arms are rotatably joined together. The manipulator is doubly protected from infiltration by unwanted gases by the high pressure gas in the manipulator and by the sealing members.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure generally relates to manipulators, and particularly to manipulators with combustion protection. 
         [0003]    2. Description of Related Art 
         [0004]    With developments in industrial technologies, manipulators are increasingly applied in hazardous environments such as those involving potentially explosive concentrations of combustible gas, dust, powder, etc. Manipulators can be utilized where human operators would be in too much danger. 
         [0005]    Manipulators often have a complex construction, including electrical components as motors, relays, electromagnetic valves, electrical cables, and so on. When a manipulator operates in a hazardous environment, to prevent combustible gas, dust or other volatile material from entering the manipulator and detonating when encountering electrical activity therein, incombustible gas is introduced into the manipulator interior to preventingress of the unstable material. 
         [0006]    The manipulator can be further protected by ensuring that the interior gas pressure of the manipulator exceeds the air pressure of the ambient environment. However, during operation of the manipulator, milling powder, paint vapor, or other combustible particulate matter may enter the manipulator through the joints thereof, thereby creating danger of explosion. This can occur even when the interior gas pressure exceeds the air pressure of the ambient environment. Additionally, when the manipulator is idle and remains in a hazardous environment, no incombustible gas is introduced into the manipulator, and the gas pressure inside the manipulator is the same as the air pressure outside the manipulator. Thus combustible gas, dust and other volatile materials can drift into the manipulator interior, and establish conditions in which an explosion is possible when the manipulator is powered up. 
         [0007]    To enhance the security of a manipulator that has been idle, high pressure gas is introduced into the manipulator before it is powered up. However, such a procedure delays the operational deployment of the manipulator. In addition, the root cause of the danger, namely the combustible material entering the manipulator through the joints, is not addressed. 
         [0008]    Therefore, there is room for improvement within the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views, and all the views are schematic. 
           [0010]      FIG. 1  is an assembled, isometric view of an embodiment of a manipulator. 
           [0011]      FIG. 2  is an enlarged view of a circled portion II of  FIG. 1 . 
           [0012]      FIG. 3  is a cutaway view of some components of the manipulator of  FIG. 1 . 
           [0013]      FIG. 4  is an enlarged view of a circled portion IV of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Referring to  FIG. 1 , a manipulator  100  includes a first arm  10 , a second arm  20 , a third arm  30 , a fourth arm  40 , a fifth arm  50 , a sixth arm  60 , and a seventh arm  70  rotatably joined to each other in that order. The manipulator  100  further includes an air-pressure system  80  and sealing members  90 . The sealing members  90  are disposed where the first arm  10  is joined with the second arm  20 . 
         [0015]    In the manipulator  100 , one end of the second arm  20  is joined with the first arm  10 . One end of the third arm  30  is joined with one side of the second arm  20 , and the other end of the third arm  30  is joined with one side of the fourth arm  40 . The fifth arm  50  is joined with one end of the fourth arm  40 . Two opposite ends of the sixth arm  60  are joined with the fifth arm  50 . One end of the seventh arm  70  is joined with the sixth arm  60 , and the other end of the seventh arm  70  is free. That is, one end of the seventh arm  70  is the free end of the manipulator  100 . In the illustrated embodiment, the axis around which the third arm  30  rotates relative to the second arm  20  is perpendicular to the axis around which the second arm  20  rotates relative to the first arm  10 , and parallel to the axis around which the fourth arm  40  rotates relative to the third arm  30 . 
         [0016]    The first arm  10  includes a main body  11 , a first connecting portion  13  formed at one end of the main body  11 , a second connecting portion  15  formed on one side of main body  11 , and a plug  17  received in the second connecting portion  15 . The second connecting portion  15  defines an inlet  151  and an outlet  153 . The first arm  10  is capable of being fixed to the ground or other equipment via the first connecting portion  13 . In the illustrated embodiment, the first connecting portion  13  is a flange, and the second connecting portion  15  is a protrusion formed on one side of the main body  11 . 
         [0017]    Referring also to  FIG. 2 , the fifth arm  50  includes a main casing  51 , two covers  53  on two opposite sides of the main casing  51 , and two gaskets  55  disposed between the covers  53  and the main casing  51 , respectively. The covers  53  are on the main casing  51 , creating a hermetical seal. The gaskets  55  ensure the seal is strong and reliable. The main casing  51  defines two tie-ins  511 . In the illustrated embodiment, the tie-ins  511  are essentially in the form of fastened, hermetical bushings. The covers  53  are fixed to the main casing  51  by fasteners. The number of fasteners is sufficient for the covers  53  to not disengage from the main casing  51  even in the event of explosive combustion inside the casing  51 . In the illustrated embodiment, there are nine fasteners. The gaskets  55  may alternatively be adhered or welded to the main casing  51 . In other embodiments, there may be only one cover  53 , and correspondingly only one gasket  55 . 
         [0018]    In other embodiments, any one or more of the other arms  10 ,  20 ,  30 ,  40 ,  60 , and  70  may include one or more gaskets  55 , in much the same way as the gaskets  55  on the fifth arm  50  are provided. 
         [0019]    The air-pressure system  80  includes an inlet conduit  81 , an outlet conduit  82 , a pressure regulating member  83 , a monitor  84 , a protecting box  85 , and a third conduit  86 . The inlet conduit  81  extends in the first arm  10 , the second arm  20 , the third arm  30 , the fourth arm  40 , and the fifth arm  50  in that order, and extends out of the fifth arm  50  through one tie-in  511  of the fifth arm  50 , and then extends back into the fifth arm  50  through the other tie-in  511 . One end of the outlet conduit  82  extends into the first arm  10 , and the other end of the outlet conduit  82  extends out of the protecting box  85 . The pressure regulating member  83  is disposed on the inlet conduit  81 , and the monitor  84  is disposed on the outlet conduit  82 . The protecting box  85  is fixed on the second connecting portion  15  of the first arm  10 , and receives the plug  17 , the pressure regulating member  83 , and the monitor  84  therein. The third conduit  86  is flexible material, with one end thereof fixed on a periphery of the protecting box  85  to receive cables connected to the plug  17  of the first arm  10 . 
         [0020]    Referring to  FIG. 1 ,  FIG. 3  and  FIG. 4 , a plurality of sealing members  90  are provided where the first arm  10  joins the second arm  20 . The sealing members  90  include at least one obturating ring  91  and at least one oil ring  93 . If the first arm  10  and the second arm  20  are joined without utilizing any sealing means, typically, many gaps are formed at the joint therebetween. Some of the gaps communicate the interior of the arms  10 ,  20  with the exterior of the arms  10 ,  20 . The sealing members  90  inlayed in these gaps isolate the interior of the arms  10 ,  20  from the exterior of the arms  10 ,  20 . In the illustrated embodiment, there are four obturating rings  91 , and there is only one oil ring  93 . In other embodiments, there may be one, two, three, or more than four obturating rings  91 , and there may be more than one oil ring  93 . That is, the number and type of sealing members  90  depends on the number of gaps that are anticipated to exist at the joint between the first and second arms  10 ,  20  in the case that no sealing means were utilized. In further or other embodiments, the sealing members  90  may include gaskets, or other suitable sealing members. 
         [0021]    In the manipulator  100 , the sealing members  90  may be inlayed in any of the joints between any two of the arms  10 ,  20 ,  30 ,  40 ,  50 ,  60 , and  70 . 
         [0022]    Referring to  FIG. 1 , in the manipulator  100 , a shell of each arm  10 ,  20 ,  30 ,  40 ,  50 ,  60 , and  70  is cast with a predetermined thickness. Such that the shells have a predetermined mechanical strength sufficient to withstand and explosive combustion event in the interior of the manipulator  100 , and the shell remains intact and the explosion is contained. 
         [0023]    In use of the manipulator  100 , non-combustible gas is introduced into the fifth arm  50  of the manipulator  100  through the inlet conduit  81 , thereby elevating the gas pressure within. The non-combustible gas is, for example, inert gas, carbon dioxide, or another suitable gas. After being introduced into the fifth arm  50 , the non-combustible gas diffuses into the first arm  10  via the fourth arm  40 , the third arm  30 , and the second arm  20 , and diffuses into the seventh arm  70  via the sixth arm  60 , and finally suffuses all the arms  10 ,  20 ,  30 ,  40 ,  50 ,  60 , and  70  of the manipulator  100 . This is achieved by the high pressure gas introduced into the manipulator  100  via the fifth arm  50  generating gas pressure in the fifth arm  50  which is higher than the gas or air pressure in the other arms  10 ,  20 ,  30 ,  40 ,  60 , and  70  of the manipulator  100 . Furthermore, since the first arm  10  is far away from the fifth arm  50 , the gas or air pressure in the first arm  10  is lower than that of any of the other arms  20 ,  30 ,  40 ,  50 ,  60 , and  70  of the manipulator  100 . 
         [0024]    The high pressure gas is capable of escaping from the manipulator  100  interior through the outlet conduit  82 . When the high pressure gas is introduced into the manipulator  100 , the pressure regulating member  83  regulates the velocity of the high pressure gas, such that the gas pressure in the manipulator  100  is controlled. When the high pressure gas diffuses out of the manipulator  100 , the monitor  84  monitors the pressure of the high pressure gas escaping through the outlet conduit  82 , so that any abnormal status of the gas pressure may be detected in real time. 
         [0025]    Since the gas pressure in the manipulator  100  is higher than the air pressure of the exterior, combustible gas, dust and other volatile matter is prevented from entering the manipulator  100 . The sealing members  90  (such as those shown in  FIG. 4 ) inlayed in the joints between two corresponding joined arms  10 ,  20 ,  30 ,  40 ,  50 ,  60 , and  70  further ensure isolation of the interior of manipulator  100 . Thereby, even when the manipulator  100  is idle, combustible gas, dust and other volatile matter is apt to not enter the manipulator  100 . Thus, the danger of combustion or explosion inside the manipulator  100  when the manipulator  100  is next powered up is minimized or even eliminated altogether. 
         [0026]    In addition, cleaning of the interior of the manipulator  100  prior to restarting the manipulator  100  is not required, thereby enhancing operational efficiency. 
         [0027]    In the manipulator  100 , the fifth arm  50  defines the tie-ins  511 . Thus when the manipulator  100  is operated in an environment with no combustible gas or air or combustible powder, the inlet conduit  81  in the manipulator  100  can be refitted. For example, the inlet conduit  81  can extend out of the fifth arm  50  through one tie-in  511  and connect to other controlling equipment. Another conduit can be added to the manipulator  100 , with two ends of the other conduit respectively connected to the other tie-in  511  of the fifth arm  50  and the outlet conduit  82 . Thus, the inlet conduit  81  is easily refitted. 
         [0028]    The protecting box  85  on the second connecting portion  15  of the first arm  10  and the third conduit  86  receive cables connected with the plug  17  inside the first arm  10 . This allows the cables to be isolated from the ambient environment, and accordingly combustible gas, dust and other volatile matter cannot enter the manipulator  100  via the cables. 
         [0029]    Since the fifth arm  50  is adjacent to the seventh arm  70  and frequently rotates, the fifth arm  50  has a greater need for protection from explosive combustion. Application of the high pressure gas into the fifth arm  50  and diffusion of the gas from the fifth arm  50  to the other arms  10 ,  20 ,  30 ,  40 ,  60 , and  70  provides the needed enhanced protection. Since the gas pressure in the first arm  10  is lower than that of other portions in the manipulator  100 , and since the monitor  84  is disposed adjacent to the first arm  10 , the gas pressure in the whole manipulator  100  achieves the needed pressure requirement as long as the pressure detected by the monitor  84  is normal. 
         [0030]    In alternative embodiments, the outlet  153  and the outlet conduit  84  can be omitted. In such case, once sufficient non-combustible gas is introduced into the manipulator  100 , the inlet conduit  81  is closed, and a monitor monitors the gas pressure in the manipulator  100 . The fifth arm  50  need not necessarily define the tie-ins  511 . Instead, the distal end of the inlet conduit  81  fixed in the fifth arm  50 . Moreover, the distal end of the inlet conduit  81  may be fixed in the sixth arm  60  or the seventh arm  70 . The second connecting portion  15  of the first arm  10  need not necessarily define the inlet  151 . Instead, one of the other arms  20 ,  30 ,  40 ,  50 ,  60 , and  70  in which the distal end of the inlet conduit  81  is fixed may define an inlet, and the inlet conduit  81  can be inserted into the manipulator  100  through such inlet. 
         [0031]    Finally, while various embodiments have been described and illustrated, the disclosure is not to be construed as being limited 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.