Abstract:
An oil suction pump has an air outlet normally closed by a valve controlled via a compression spring, and the valve may be pushed backward by flowing air to open the air outlet. Therefore, the oil suction pump may be connected to an air compressor or to a manual air pump to obtain flowing air to push backward the valve and thereby open the air outlet and vacuumize a container connected to the oil suction pump for sucking oil into the container. A user may freely select to operate the oil suction pump via the air compressor or the manual air pump depending on actual need.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to an oil suction pump, and more particularly to an oil suction pump having an air outlet normally closed by a valve and openable by air flowing against and pushing the valve backward. Therefore, a manual air pump may be externally connected to the oil suction pump, allowing a user to operate the oil suction pump via a power-actuated air compressor or the manual air pump, depending on actual need.  
       BACKGROUND OF THE INVENTION  
       [0002]     U.S. Pat. No. 6,736,603 B2 discloses an oil suction pump invented by the same inventor of the present invention. The oil suction pump disclosed in U.S. Pat. No. 6,736,603 B2 includes a float that ascends with the level of oil sucked into a container connected with the oil suction pump, such that an air intake valve for controlling the suction of oil is automatically closed when the level of oil sucked into the container reaches a preset height. It is noted the oil suction pump disclosed in U.S. Pat. No. 6,736,603 B2 is operable only when it is connected to a power-actuated air compressor. In other words, the oil suction pump disclosed in U.S. Pat. No. 6,736,603 B2 is workable to automatically suck oil only in a power-actuated manner. The oil suction pump is completely useless when it is used in an environment without power supply.  
         [0003]     Although there are many commercially available oil suction pumps, either power-driven or manual-automatic ones, such as the oil suction pump disclosed in U.S. Pat. No. 6,558,138 B2, none of them are similar to U.S. Pat. No. 6,736,603 B2 in terms of the operating manner thereof. That is, none of the currently available oil suction pumps use a float to control the automatic close of the air intake valve for controlling the suction of oil and prevent oil from jetting out of the air outlet in the process of sucking oil into a container.  
         [0004]     It is therefore tried by the inventor to improve the oil suction pump disclosed in U.S. Pat. No. 6,736,603 B2, so as to develop an oil suction pump that has expanded range of application, and allows a user to automatically operate the oil suction pump via a power-actuated air compressor or to manually operate the oil suction pump via a manual air pump externally connected to the oil suction pump, depending on actual need.  
       SUMMARY OF THE INVENTION  
       [0005]     A primary object of the present invention is to provide an oil suction pump, in which a normally closed air outlet is controlled by flowing air to open. Therefore, a manual air pump may be externally connected to the oil suction pump, allowing the oil suction pump to be operated via a power-actuated air compressor or the manual air pump, so that the oil suction pump has expanded range of application and may be more conveniently operated. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]     The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein  
         [0007]      FIG. 1  is a vertical sectional view of a conventional oil suction pump;  
         [0008]      FIG. 2  is a perspective view of an oil suction pump according to the present invention;  
         [0009]      FIG. 3  is a vertical sectional view of the oil suction pump of  FIG. 2 ;  
         [0010]      FIG. 4  is a fragmentary and enlarged sectional view of  FIG. 3  showing the structure of the oil suction pump of the present invention;  
         [0011]      FIG. 5  is another vertical sectional view of the oil suction pump of the present invention showing the manner in which high-pressure air flows through an air outlet of the oil suction pump;  
         [0012]      FIG. 6  is a fragmentary and enlarged sectional view of  FIG. 5  showing the structure of the oil suction pump of the present invention;  
         [0013]      FIG. 7  is a vertical sectional view of the oil suction pump of the present invention showing the operating of a manual air pump to suck in air;  
         [0014]      FIG. 8  is a sectional view of a relief valve included in the oil suction pump of the present invention; and  
         [0015]      FIG. 9  is a sectional view of the relief valve of  FIG. 8  in a position of relieving air.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0016]     Please refer to  FIG. 1  that is a vertical sectional view of a conventional oil suction pump, based on which the present invention is made. As shown, the oil suction pump of  FIG. 1  includes a push switch  1 , a shaft  2  located below the push switch  1 , a first compression spring  3  provided around an upper portion of the shaft  2  for the push switch  1  to be elastically moved downward within a predetermined range, and an enclosed passage  4  for receiving the shaft  2  therein.  
         [0017]     The enclosed passage  4  has an open upper end communicating with the push switch  1  and is communicable at two opposite sides with an air outlet pipe  5  and an air inlet pipe  6 , respectively. An open lower end of the enclosed passage  4  communicates with a slide way  8 , in which a first end of a float arm  7  is located.  
         [0018]     First and second airtight seal rings  91 ,  92  are provided near upper and lower ends, respectively, of the shaft  2 , so that the shaft  2  located in the enclosed passage  4  is always in an airtight relation with the enclosed passage  4  near the upper and the lower end of the shaft  2 . A third airtight seal ring  93  is provided near a middle portion of the shaft  2 . When the shaft  2  is vertically moved in the enclosed passage  4 , the third seal ring  93  is also moved to different height to either close or open a communicating path between an inner end of the air outlet pipe  5  and the enclosed passage  4 . A second compression spring  31  is provided near the middle portion of the shaft  2  to control a magnitude of vertical movement of the shaft  2  in the enclosed passage  4 . More particularly, the enclosed passage  4  includes a downward flared portion in its inner bore. When the shaft  2  is not downward moved to compress the second compression spring  31 , the third airtight seal ring  93  on the shaft  2  is just located at a height to firmly abut against the flared portion of the enclosed passage  4  and therefore seals the communicating path between the enclosed passage  4  and the air outlet pipe  5 . And, when the shaft  2  is moved downward to compress the second compression spring  31 , the third airtight seal ring  93  is also moved downward to separate from the flared portion of the enclosed passage  4  for the air outlet pipe  5  to communicate with the enclosed passage  4 .  
         [0019]     The shaft  2  has a lower end in the form of a hook  21 . The hook  21  is located in the slide way  8  to detachably engage with a hook  71  provided at the first end of the float arm  7  horizontally located below the lower end of the shaft  2 . The float arm  7  is pivotally turnable about a supporting point  72  provided close to and below the hook  71 . A second end of the float arm  7  is pivotally connected to a float  73 . When the conventional oil suction pump of  FIG. 1  is connected to a container  10  for sucking oil  11  thereinto, the float  73  ascends when the oil  11  reaches a predetermined level in the container  10 .  
         [0020]     The conventional oil suction pump of  FIG. 1  may also be internally provided with an air drawing passage  12  to communicate with the air outlet pipe  5 . A floating member  13  is provided in the air drawing passage  12  as an auxiliary means to control the air outlet pipe  5 . The floating member  13  has a diameter-reduced neck portion provided near an upper end thereof, and a fourth airtight seal ring  94  is provided around the neck portion. When the oil  11  sucked into the container  10  reaches such a level to move the floating member  13  upward, the fourth airtight seal ring  94  is also moved upward to close the air drawing passage  12  and therefore prevents the oil  11  from flowing into and jetting out via the air outlet pipe  5 .  
         [0021]     Please refer to  FIGS. 2 and 3  that are perspective and vertical sectional views, respectively, of an oil suction pump according to the present invention. In addition to the above-mentioned structure included in the conventional oil suction pump of  FIG. 1 , the present invention further includes a new cover mounted to a front end of an air outlet  14  to replace that used in the conventional oil suction pump of  FIG. 1 . The new cover consists of a housing  15 , a muffle  166 , and a valve set  16 .  
         [0022]     The housing  15  is provided on an inner wall surface of a rear end close to the front end of the air outlet  14  with screw threads  152 , so that the housing  15  may be screwed onto an outer wall surface of the front end of the air outlet  14 . The housing  15  is also provided on its circumferential wall with several rows of axially sequentially arranged vents  151 . A front end of the housing  15  has a radially inward projected portion, a center of which is molded into a sleeve seat  153 . A radially inward annular projection  165  is formed around an inner bore of the sleeve seat  153  near an inner end thereof.  
         [0023]     The valve set  16  includes a base  161 , a compression spring  162 , and a sealing head  163 . The base  161  is provided around an outer circumferential surface with an annular groove  1611 , which is fitly engaged with the annular projection  165  on the sleeve seat  153  when the base  161  is set in the inner bore of the sleeve seat  153 . The base  161  is provided at a central area with a bore  1612  to slidably receive a long shaft  164  rearward extended from a front portion of the sealing head  163 . A free end of the long shaft  164  is expanded after the long shaft  164  has been inserted into the bore  1612 , so that the long shaft  164  is prevented from separating from the bore  1612  of the base  161 . The compression spring  162  is mounted around the long shaft  164  behind the front portion of the sealing head  163  to provide a restoring force for the long shaft  164  to elastically reciprocate in the bore  1612  of the base  161 . The front portion of the sealing head  163  in front of the long shaft  164  is a cylindrical body having a neck portion  167 , around which an airtight seal ring  168  is mounted. The compression spring  162  normally pushes the front portion of the sealing head  163  against a front opening  141  of the air outlet  14  of the air suction pump, such that the airtight seal ring  168  mounted on the neck portion  167  of the sealing head  163  tightly seals the front opening  141 .  
         [0024]     With the valve set  16  mounted in the housing  15  and the vents  151  formed on the housing  15 , it is possible to conveniently connect a manual air pump  17  and a pipe holder  18  for temporarily holding an oil suction pipe (not shown) to an outer shell of the oil suction pump. The manual air pump  17  is provided at predetermined positions with a movable connector  171  for connecting to the air inlet pipe  6 , and a relief valve  20 .  
         [0025]     Please refer to  FIGS. 4, 5 , and  6  for the operation of the oil suction pump of the present invention. When a user wants to use a power-actuated air compressor to operate the oil suction pump, simply connects an air pipe connector on the air compressor to the air inlet pipe  6  of the oil suction pump, and high-pressure air  62  supplied from the air compressor, as indicated by the arrows in  FIGS. 5 and 6 , would push the sealing head  163  away from the front opening  141  of the air outlet  14  and compress the compression spring  162 , so that the high-pressure air  62  passes the muffle  166  and is muffled before flowing out of the housing  15  via the vents  151 . When the air is blown out of the container  10 , the container  10  is vacuumized to allow suction of oil  11  into the container  10 . When the oil suction is completed, the air compressor is shut off, and the compression spring  162  mounted on the long shaft  164  of the sealing head  163  automatically restores from the compressed state to move the sealing head  163  forward, so that the front portion of the sealing head  163  is pushed against the front opening  141  of the air inlet  14  of the oil suction pump with the airtight seal ring  168  around the neck portion  167  of the sealing head  163  tightly sealing the front opening  141  again.  
         [0026]     On the other hand, when a user wants to manually operate the oil suction pump of the present invention, simply connects the movable connector  171  on the manual air pump  17  to the air inlet pipe  6  of the oil suction pump, as shown in  FIG. 7 . Before the manual air pump  17  is operated, there is not any high-pressure air  62  flowing into the air outlet  14  to push open the valve set  16 , and the valve set  16  is in a closed state. The user needs only to vertically push and pull a handle  172  of the manual air pump  17 , and the container  10  may be vacuumized to allow suction of oil into the container  10 .  
         [0027]      FIG. 8  shows the structure of the relief valve  20  provided on the outer shell of the manual air pump  17 . As shown, the relief valve  20  is internally provided with a push button  201 , a compression spring  202 , a sealing head  203 , and an airtight seal ring  204  mounted on the sealing head  203  to normally seal an air passage  205  in the relief valve  20 . When the push button  201  is downward pressed, the sealing head  203  is moved downward simultaneously, so that the airtight seal ring  204  on the sealing head  203  does not seal the air passage  205 , as shown in  FIG. 9 , and air in the manual air pump  17  may be relieved via the air passage  205 , and the manual air pump  17  is ready for use next time.