Patent Publication Number: US-2007110602-A1

Title: Pump

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates to a pump, more particularly to a pump adapted to dispense liquid from a container.  
      2. Description of the Related Art  
      As shown in  FIG. 1  and  FIG. 2 , a container assembly for a liquid, such as shampoo, lotion, etc., includes a container (not shown) for receiving the liquid, a conventional pump  10 , and a nozzle assembly  17  including a nozzle  171 , a cap  172 , and a riser tube  174  (partially shown in  FIG. 1 ) . The nozzle  171  and the riser tuber  174  are coupled to the conventional pump  10  at opposite ends, respectively. The conventional pump  10  is movable together with the nozzle  171  relative to the container such that the liquid in the container can be dispensed from the container through the riser tube  174  and out of the nozzle  171 .  
      The conventional pump  10  includes a tubular main body  11 , an inlet valve  12 , a delivery shaft  13 , a piston  14 , an elastic component  16 , and a delivery tube  15 .  
      The main body  11  extends along an axis (X) and has an upper body part  111  confining a chamber  113 , and a lower body part  112  connected to the upper body part  111  and confining an inlet  114  distal from the upper body part  111 .  
      The inlet valve  12  includes a valve seat  121  formed in the lower body part  112 , and a ball member  122  disposed in the lower body part  112  and seated movably on the valve seat  121  to block fluid communication between the inlet  114  and the chamber  113 .  
      The delivery shaft  13  extends through the upper body part  111  into the chamber  113  along the axis (X), and includes an upper delivery segment  131 , and a lower piston-seating segment  133  connected to the delivery segment  131 . The delivery segment  131  is formed with two channels  132  to be disposed in fluid communication with the chamber  113 .  
      The piston  14  is disposed movably in the chamber  113  along the axis (X), and includes a sleeve portion  141  sleeved on the delivery segment  131  of the delivery shaft  13 , a peripheral portion  142  disposed around the sleeve portion  141  and in sealing contact with the upper body part  111 , and a connecting portion  143  that interconnects the sleeve and peripheral portions  141 ,  142 .  
      The elastic component  16  is a compression spring that is disposed in the main body  11 , that is sleeved on the piston-seating segment  133  of the delivery shaft  13 , and that has opposite ends that abut against the lower body part  112  and the piston-seating segment  133 , respectively. The elastic component  16  provides a biasing force to move the delivery shaft  13  away from the inlet valve  12 , and to cause the piston-seating segment  133  to push the sleeve portion  141  of the piston  14  away from the inlet valve  12 .  
      The delivery tube  15  is sleeved on the delivery segment  131  of the delivery shaft  13 , is connected to the nozzle  171 , and is spaced apart from the piston  14  at a separation distance (D) . The delivery tube  15  is operable to drive movement of the delivery shaft  13  toward the inlet valve  12  against urging action of the elastic component  16 .  
      As shown in  FIG. 3 , to dispense the liquid from the container, the nozzle  171  is pressed downwardly along the axis (X) to actuate the delivery tube  15  to push the delivery shaft  13  toward the inlet valve  12  until the delivery tube  15  abuts against the sleeve portion  141  of the piston  14 , at which point the piston-seating segment  133  of the delivery shaft  13  is spaced apart from the sleeve portion  141  of the piston  14  at the separation distance (D) due to pressure in the chamber  113 , such that the channels  132  are in fluid communication with the chamber  113 . The nozzle  171  is pressed downwardly in the direction as illustrated by arrow (A) along the axis (X) further to actuate the delivery tube  15  to push the delivery shaft  13  and the piston  14  toward the inlet valve  12 . At the same time, the elastic component  16  is compressed, and the pressure in the chamber  113  is increased, such that the liquid in the chamber  113  is dispensed through the channels  132  out of the nozzle  171 .  
      As shown in  FIG.4 , when the nozzle  171  is released, the biasing force of the elastic component  16  moves the delivery shaft  13  away from the inlet valve  12  in the direction as illustrated by arrow (B), and causes the piston-seating segment  133  of the delivery shaft  13  to abut against the sleeve portion  141  of the piston  14  away from the inlet valve  12 , such that fluid communication between the channels  132  and the chamber  113  is prevented. Due to pressure difference inside the chamber  113  and the riser tube  174 , the ball member  122  moves away from the valve seat  121 , such that the inlet  114  is in fluid communication with the chamber  113  to permit flow of the liquid from the container into the chamber  113 . As the pressure inside the chamber  113  and that inside the riser tube  174  reach equilibrium, the ball member  122  is seated once more on the valve seat  121  such that fluid communication between the inlet  114  and the chamber  113  is blocked once again, as best illustrated in  FIG. 1 .  
      As shown in  FIG. 5 , when the liquid is highly viscous, it is likely to accumulate on the valve seat  121 , such that the ball member  122  cannot be properly seated thereon to block fluid communication between the inlet  114  and the chamber  113 . As result, the liquid cannot be dispensed from the container.  
     SUMMARY OF THE INVENTION  
      Therefore, the object of the present invention is to provide a pump that is adapted to dispense highly viscous liquids from a container.  
      According to the present invention, there is provided a pump that includes a tubular main body, an inlet valve, a delivery shaft, a piston, an elastic component, and a delivery tube. The main body extends along an axis and has an upper body part confining a chamber, and a lower body part connected to the upper body part and confining an inlet distal from the upper body part. The inlet valve includes a valve seat formed in the lower body part, and a ball member disposed in the lower body part and seated movably on the valve seat to block fluid communication between the inlet and the chamber. The delivery shaft extends through the upper body part into the chamber along the axis, and includes an upper delivery segment, a lower valve-control segment, and a piston-seating segment disposed between the delivery and valve-control segments. The delivery segment of the delivery shaft is formed with a channel to be disposed in fluid communication with the chamber. The piston is disposed movably in the chamber and includes a sleeve portion sleeved on the delivery segment of the delivery shaft, a peripheral portion disposed around the sleeve portion and in sealing contact with the upper body part, and a connecting portion that interconnects the sleeve and peripheral portions. The elastic component is disposed in the main body for providing a biasing force to move the valve-control segment of the delivery shaft away from the inlet valve, and to cause the piston-seating segment of the delivery shaft to push the sleeve portion of the piston away from the inlet valve. The delivery tube is sleeved on the delivery segment of the delivery shaft, and is operable to drive movement of the delivery shaft toward the inlet valve such that the valve-control segment of the delivery shaft forces the ball member to be seated on the valve seat, and to drive movement of the piston toward the inlet valve. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which:  
       FIG. 1  is a sectional view of a conventional pump coupled to a nozzle assembly;  
       FIG. 2  is a top sectional view taken along line II-II in  FIG. 1 ;  
       FIG. 3  is a sectional view similar to  FIG. 1 , illustrating pressing of a nozzle;  
       FIG. 4  is a sectional view similar to  FIG. 1 , illustrating releasing of the nozzle;  
       FIG. 5  is a sectional view similar to  FIG. 1 , illustrating a drawback of the conventional pump;  
       FIG. 6  is a sectional view of the first preferred embodiment of a pump coupled to a nozzle assembly according to the present invention;  
       FIG. 7  is a top sectional view of the first preferred embodiment taken along line VII-VII in  FIG. 6 ;  
       FIG. 8  is a sectional view of the first preferred embodiment, illustrating pressing of a nozzle;  
       FIG. 9  is a sectional view of the first preferred embodiment, illustrating releasing of the nozzle;  
       FIG. 10  is a top sectional view of the second preferred embodiment of a pump according to the present invention;  
       FIG. 11  is a sectional view of the third preferred embodiment of a pump coupled to a nozzle assembly according to the present invention;  
       FIG. 12  is a sectional view of the third preferred embodiment, illustrating pressing of a nozzle;  
       FIG. 13  is a sectional view of the fourth preferred embodiment of a pump coupled to a nozzle assembly according to the present invention; and  
       FIG. 14  is a sectional view of the fifth preferred embodiment of a pump coupled to a nozzle assembly according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Before the present invention is described in greater detail, it should be noted herein that like elements are denoted by the same reference numerals throughout the disclosure.  
      As shown in  FIG. 6  and  FIG. 7 , the first preferred embodiment of a pump  200  according to the present invention is adapted to be coupled to the conventional nozzle assembly  17  of  FIG. 1 . The pump  200  includes a tubular main body  20 , an inlet valve  30 , a delivery shaft  40 , a piston  50 , an elastic component  70 , and a delivery tube  60 .  
      The tubular main body  20  extends along the axis (X) and has an upper body part  201  confining a chamber  203 , and a lower body part  202  connected to the upper body part  201  and confining an inlet  204  distal from the upper body part  201 . In this embodiment, the upper body part  201  has a larger cross-section than that of the lower body part  202 . In addition, the main body  20  further has a shoulder part  205  between the upper and lower body parts  201 ,  202 .  
      The inlet valve  30  includes a valve seat  301  formed in the lower body part  202 , and a ball member  302  disposed in the lower body part  202  and seated movably on the valve seat  301  to block fluid communication between the inlet  204  and the chamber  203 .  
      The delivery shaft  40  extends through the upper body part  201  into the chamber  203  along the axis (X), and includes an upper delivery segment  401 , a lower valve-control segment  402 , and a piston-seating segment  403  disposed between the delivery and valve-control segments  401 ,  402 . The delivery segment  401  is formed with a channel  404  to be disposed in fluid communication with the chamber  203 . In this embodiment, the delivery, valve-control, and piston-seating segments  401 ,  402 ,  403  are formed integrally. The valve-control segment  402  includes an upper portion  4021  and a lower portion  4022  having a cross-section smaller than that of the upper portion  4021 . The delivery shaft  40  has a length such that when the piston-seating segment  403  of the delivery shaft  40  abuts against the shoulder part  205  of the main body  20 , the valve-control segment  402  of the delivery shaft  40  abuts against the ball member  302 , thereby forcing the ball member  302  to be seated on the valve seat  301  to block fluid communication between the inlet  204  and the chamber  203 , as best shown in  FIG. 8 .  
      The piston  50  is disposed movably in the chamber  203 , and includes a sleeve portion  501  sleeved on the delivery segment  401  of the delivery shaft  40 , a peripheral portion  502  disposed around the sleeve portion  501  and in sealing contact with the upper body part  201 , and a connecting portion  503  that interconnects the sleeve and peripheral portions  501 ,  502 . Fluid communication between the channel  404  and the chamber  203  is prevented when the piston-seating segment  403  of the delivery shaft  40  abuts against the sleeve portion  501  of the piston  50 .  
      The elastic component  70  is disposed in the main body  20  for providing a biasing force to move the valve-control segment  402  of the delivery shaft  40  away from the inlet valve  30 , and to cause the piston-seating segment  403  of the delivery shaft  40  to push the sleeve portion  501  of the piston  50  away from the inlet valve  30 . In this embodiment, the elastic component  70  is a compression spring that is sleeved on the valve-control segment  402  of the delivery shaft  40 , and that has opposite ends abutting against the lower body part  202  and the piston-seating segment  403 , respectively.  
      The delivery tube  60  is sleeved on the delivery segment  401  of the delivery shaft  40 , and is spaced apart from the piston  50  at a separation distance (D). As best shown in  FIG. 8 , the delivery tube  60  is operable via the nozzle  171  to drive movement of the delivery shaft  40  toward the inlet valve  30  against urging action of the elastic component  70 , such that the valve-control segment  402  of the delivery shaft  40  forces the ball member  302  to be seated on the valve seat  301 , and to drive movement of the piston  50  toward the inlet valve  30 . Pressure in the chamber  203  when the piston  50  is driven by the delivery tube  60  toward the inlet valve  30  causes the sleeve portion  501  of the piston  50  to move away from the piston-seating segment  403  of the delivery shaft  40  to permit fluid communication between the channel  404  and the chamber  203 .  
      In this embodiment, the shoulder part  205  of the main body  20  cooperates with the piston-seating segment  403  of the delivery shaft  40  to limit movement of the delivery shaft  40  toward the inlet valve  30  upon operation of the delivery tube  60  via the nozzle  171 . In addition, as best shown in  FIG. 7 , the delivery segment  401  of the delivery shaft  40  has an outer surface  406 , and the channel  404  includes four fluid ducts  405  that extend parallel to the axis (X), that are angularly spaced apart from each other relative to the axis (X), and that are indented from the outer surface  406  of the delivery segment  401  toward the axis (X).  
      As shown in  FIG. 8  and  FIG. 9 , the pump  200  is coupled to the nozzle assembly  17  that includes the nozzle  171  and the cap  172 , and is applied to a container (not shown) filled with a liquid (not shown). The following steps are taken when the liquid is to be dispensed from the container.  
      (1) The nozzle  171  is pressed downwardly in the direction as illustrated by arrow (C) along the axis (X) to actuate the delivery tube  60  to push the delivery shaft  40  toward the inlet valve  30  until the delivery tube  60  abuts against the sleeve portion  501  of the piston  50 , at which point the piston-seating segment  403  of the delivery shaft  40  is spaced apart from the sleeve portion  501  of the piston  50  at the separation distance (D) due to pressure in the chamber  203 , such that the channel  404  is in fluid communication with the chamber  203 , as best illustrated in  FIG.8 .  
      (2) The nozzle  171  is pressed downwardly in the direction as illustrated by arrow (C) along the axis (X) further to actuate the delivery tube  60  to push the delivery shaft  40  and the piston  50  toward the inlet valve  30  until the piston-seating segment  403  of the delivery shaft  40  abuts against the shoulder  205  of the main body  20 , at which point, the valve-control segment  402  of the delivery shaft  40  forces the ball member  302  to be seated on the valve seat  301 . At the same time, the elastic component  70  is compressed, and the pressure in the chamber  203  is increased, such that the liquid in the chamber  203  is dispensed through the channel  404  out of the nozzle  171 , as best illustrated in  FIG. 8 .  
      (3) The nozzle  171  is released so that the biasing force of the elastic component  70  moves the delivery shaft  40  away from the inlet valve  30  in the direction as illustrated by arrow (E), and causes the piston-seating segment  403  of the delivery shaft  40  to abut against the sleeve portion  501  of the piston  50  away from the inlet valve  30 , such that fluid communication between the channel  404  and the chamber  203  is prevented. At the same time, the delivery shaft  40  and the piston  50  are pushed upward along the axis (X) in the direction as illustrated by arrow (E) . Due to pressure difference inside the chamber  203  and the riser tube  174 , the ball member  302  moves away from the valve seat  301 , such that the inlet  204  is in fluid communication with the chamber  203  to permit flow of the liquid from the container into the chamber  203 , as best shown in  FIG.9 .  
      Since the valve-control segment  402  of the delivery shaft  40  forces the ball member  302  to be seated on the valve seat  301  when dispensing the liquid from the chamber  203 , the liquid can be drawn from the container into the chamber  203  when the nozzle  171  is subsequently released.  
      Therefore, by ensuring a suitable length for the delivery shaft  40 , such that the valve-control segment  402  is capable of forcing the ball member  302  to be seated on the valve seat  301 , the pump  200  is clear of the drawback of the prior art regardless of the weight of the ball member  302  and the viscosity of the liquid in the container.  
      As shown in  FIG. 10 , the second preferred embodiment of a pump  200 ′ according to the present invention differs from the first preferred embodiment in that the channel  404 ′ includes three, instead of four, fluid ducts  405 ′ that extend parallel to the axis (X), that are angularly spaced apart from each other relative to the axis (X), and that are indented from the outer surface  406 ′ of the delivery segment  401 ′ of the delivery shaft  40 ′ toward the axis (X).  
      As shown in  FIG. 11 , the third preferred embodiment of a pump  200 ″ according to the present invention differs from the first preferred embodiment in that the channel  404 ″ includes one, instead of four, fluid duct  405 ″ that extends along the axis (X). In addition, the delivery segment  401 ″ of the delivery shaft  40 ″ is further formed with a radial port  407  to communicate fluidly the channel  404 ″ and the chamber  203 , as shown in  FIG. 12 .  
      As shown in  FIG. 13 , the fourth preferred embodiment of a pump  200   a  according to the present invention differs from the first preferred embodiment in that the valve-control segment  402   a  of the delivery shaft  40   a  has a uniform cross-section.  
      As shown in  FIG. 14 , the fifth preferred embodiment of a pump  200   b  according to the present invention differs from the first preferred embodiment in that the upper portion  4021   b  of the valve-control segment  402   b  of the delivery shaft  40   b  is formed with a plurality of troughs  4023 .  
      While the present invention has been described in connection with what is considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation and equivalent arrangements.