Pneumatic pump

Abstract

A pneumatic pump has a valve body having a piston compartment and a receiving compartment, wherein a piston is slidably and sealedly disposed in the valve body to move between a first position and a second position. The valve body also has an exit opening communicating with the piston compartment and a resilient element to help pushing the piston to the first position. An actuator pumps air into the piston compartment and pushes the piston to the second position. The pneumatic pump further has a valve control which has a sealing member sealedly formed at the piston compartment, a driving member which is connected to the exiting opening, wherein a pressure drives the driving member automatically to unseal the sealing member to release the air inside the piston compartment to a releasing cavity and eventually allows the piston to move back to its original position.

1 . A pneumatic pump, comprising:
 a valve body having a valve chamber defining a rear piston compartment and a front receiving compartment, and an air exiting passage having an exit opening communicating with said valve chamber for releasing air therewithin;   a piston sealedly disposed in said valve body between said rear piston compartment and said front receiving compartment in a slidably movable manner;   an actuator for pumping said air into said valve chamber of said valve body to forwardly move said piston from a first position to a second position;   a resilient element disposed in said receiving compartment for applying an urging force against said piston to backwardly push said piston from said second position back to said first position;   a valve control, which is sealedly mounted to said valve body to sealedly enclose said valve chamber, comprising:   a pressuring arrangement having a releasing cavity communicating with said piston compartment and a control cavity communicating with said valve chamber through said air exiting passage for controlling a pressure between said rear piston compartment and said control cavity;   a sealing member sealedly mounted at said releasing cavity in a slidably movable manner for preventing air flowing from said rear piston compartment to said releasing cavity;   a driving member sealedly disposed in said control cavity in a slidably movable manner to divide said control cavity into a first compartment and a second compartment, wherein said driving member is coupled with said sealing member to drive said sealing member to slidably unseal said releasing cavity; and   an air discharging passage extended from said releasing cavity for discharging said air therewithin, wherein when said actuator pumps said air into said valve chamber to push said piston until said rear piston compartment is communicating with said exit opening of said air exiting passage, said air within said rear piston compartment is released to said second compartment of said control cavity, wherein when said pressure within said rear piston compartment is balanced with said pressure of said second compartment, said driving member is pressurized to push said sealing member to slidably unseal said releasing cavity for releasing said air therewithin through said air discharging passage, wherein when said piston is pushed by said resilient element back to said first position and to seal with said exit opening, said air within said rear piston compartment is forced to release to said air discharging passage through said releasing cavity until said sealing member is pushed by said piston to seal said releasing cavity so as to minimize said pressure of said rear piston compartment to ensure said piston moves back to said first position.   
   
   
       2 . The pneumatic pump, as recited in  claim 1 , wherein a circumferential size of said driving member is larger than a circumferential size of said sealing member such that under a balanced pressure between said second compartment and said rear piston compartment, said driving member is pushed forwardly to drive said sealing member to unseal said releasing cavity. 
   
   
       3 . The pneumatic pump, as recited in  claim 1 , wherein said releasing cavity has a first cavity portion having a circumferential size corresponding to a size of said sealing member for said sealing member sealedly sliding at said first cavity portion, and a second cavity portion, having a circumferential size smaller than said circumferential size of said first cavity portion, communicating with said air discharging passage such that when said sealing member is slidably pushed to seal at said first cavity portion of said releasing cavity, said air within said releasing cavity is released to said air discharging passage through said second cavity portion of said releasing cavity. 
   
   
       4 . The pneumatic pump, as recited in  claim 2 , wherein said releasing cavity has a first cavity portion having a circumferential size corresponding to a size of said sealing member for said sealing member sealedly sliding at said first cavity portion, and a second cavity portion, having a circumferential size smaller than said circumferential size of said first cavity portion, communicating with said air discharging passage such that when said sealing member is slidably pushed to seal at said first cavity portion of said releasing cavity, said air within said releasing cavity is released to said air discharging passage through said second cavity portion of said releasing cavity. 
   
   
       5 . The pneumatic pump, as recited in  claim 1 , wherein said exit opening is formed at said valve body at a position that when said piston is backwardly moved to locate at said first position, said receiving cavity is communicating with said air exiting passage via said exit opening while a volume of said rear piston compartment is minimized, wherein when said piston is forwardly moved to locate at said second position, said piston compartment is communicating with said air exiting passage via said exit opening while a volume of said receiving compartment is minimized. 
   
   
       6 . The pneumatic pump, as recited in  claim 4 , wherein said exit opening is formed at said valve body at a position that when said piston is backwardly moved to locate at said first position, said receiving cavity is communicating with said air exiting passage via said exit opening while a volume of said rear piston compartment is minimized, wherein when said piston is forwardly moved to locate at said second position, said piston compartment is communicating with said air exiting passage via said exit opening while a volume of said receiving compartment is minimized. 
   
   
       7 . The pneumatic pump, as recited in  claim 1 , wherein said valve control further has an air guiding passage extended from said control cavity to align with said air exiting passage for guiding said air along said air exiting passage to said control cavity through said air guiding passage. 
   
   
       8 . The pneumatic pump, as recited in  claim 6 , wherein said valve control further has an air guiding passage extended from said control cavity to align with said air exiting passage for guiding said air along said air exiting passage to said control cavity through said air guiding passage. 
   
   
       9 . The pneumatic pump, as recited in  claim 1 , wherein said valve control further comprises a driving shaft coupling between said sealing member and said driving member such that when said driving member is pushed forwardly, said sealing member is concurrently moved via said driving shaft to unseal said releasing cavity. 
   
   
       10 . The pneumatic pump, as recited in  claim 8 , wherein said valve control further comprises a driving shaft coupling between said sealing member and said driving member such that when said driving member is pushed forwardly, said sealing member is concurrently moved via said driving shaft to unseal said releasing cavity. 
   
   
       11 . The pneumatic pump, as recited in  claim 1 , wherein said valve body comprises a sidewall and a tubular wall having two ends sealedly mounted at said sidewall and said valve control to define said valve chamber within said tubular wall, wherein said piston compartment is defined within said piston, said tubular wall and said valve control while said receiving compartment is defined within said piston, said tubular wall and said sidewall. 
   
   
       12 . The pneumatic pump, as recited in  claim 10 , wherein said valve body comprises a sidewall and a tubular wall having two ends sealedly mounted at said sidewall and said valve control to define said valve chamber within said tubular wall, wherein said piston compartment is defined within said piston, said tubular wall and said valve control while said receiving compartment is defined within said piston, said tubular wall and said sidewall. 
   
   
       13 . The pneumatic pump, as recited in  claim 11 , wherein said air exiting passage is enclosedly embedded along said tubular wall at a position that said exit opening is formed at an inner surface of said tubular wall to communicate with said valve chamber. 
   
   
       14 . The pneumatic pump, as recited in  claim 12 , wherein said air exiting passage is enclosedly embedded along said tubular wall at a position that said exit opening is formed at an inner surface of said tubular wall to communicate with said valve chamber. 
   
   
       15 . The pneumatic pump, as recited in  claim 12 , wherein said resilient element comprises a compression spring having two ends biasing against said sidewall and said piston to push said piston towards said valve control so as to ensure said piston slidably moving back to said first position from said second position. 
   
   
       16 . The pneumatic pump, as recited in  claim 14 , wherein said resilient element comprises a compression spring having two ends biasing against said sidewall and said piston to push said piston towards said valve control so as to ensure said piston slidably moving back to said first position from said second position. 
   
   
       17 . The pneumatic pump, as recited in  claim 1 , wherein said piston further comprises a sealing ring and a spaced apart guiding ring coaxially mounted at an outer circumferential wall of said piston to sealedly contact with an inner circumferential wall of said valve chamber, wherein a sliding groove is indently formed around said outer circumferential wall of said piston between said sealing ring and said guiding ring to define a gap is formed between said outer circumferential wall of said piston and said inner circumferential wall of said valve chamber so as to allow said piston to slide within said valve chamber smoothly. 
   
   
       18 . The pneumatic pump, as recited in  claim 16 , wherein said piston further comprises a sealing ring and a spaced apart guiding ring coaxially mounted at an outer circumferential wall of said piston to sealedly contact with an inner circumferential wall of said valve chamber, wherein a sliding groove is indently formed around said outer circumferential wall of said piston between said sealing ring and said guiding ring to define a gap is formed between said outer circumferential wall of said piston and said inner circumferential wall of said valve chamber so as to allow said piston to slide within said valve chamber smoothly. 
   
   
       19 . The pneumatic pump, as recited in  claim 18 , wherein said piston further comprises a sealing ring and a spaced apart guiding ring coaxially mounted at an outer circumferential wall of said piston to sealedly contact with an inner circumferential wall of said valve chamber, wherein a sliding groove is indently formed around said outer circumferential wall of said piston between said sealing ring and said guiding ring to define a gap is formed between said outer circumferential wall of said piston and said inner circumferential wall of said valve chamber so as to allow said piston to slide within said valve chamber smoothly. 
   
   
       20 . The pneumatic pump, as recited in  claim 19 , wherein said piston further has a pressuring passage formed thereon to communicate with said piston compartment with said receiving compartment for allowing said piston moving back to said first position rapidly.