Patent Publication Number: US-11655808-B2

Title: Variable-pressure air pump

Description:
CROSS REFERENCE 
     This application is a continuation-in-part of U.S. application Ser. No. 16/881,391, filed on May 22, 2020, which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an air pump and, particularly, to a variable-pressure air pump. 
     2. Description of the Related Art 
     It is noticed that all existing air pumps try to focus on improving inflation efficiency, but no matter how the efficiency is improved, the cross-sectional areas of cylinders are inversely proportional to the pressure, so it is impossible to improve the inflation rate and the inflation effect at the same time. 
     Taiwan Pat. No. 228257 discloses an air pump convertible between a first mode for outputting high volume of air and a second mode for outputting high-pressure air. The air pump includes two cylinders being operable between a first mode in which the first and the second cylinders move relative to one another to output high volume of air to quickly inflate an object, and a second mode in which the second cylinder does not move relative to the first cylinder to output high-pressure air. 
     Generally, a user grasps on a head of the pump with one hand and a handle of the pump with the other hand upon operating the pump. However, when the pump is directly connected to a valve of a tire to be inflated, it is noted that the user is unable to hold the head conveniently and operate the pump smoothly. 
     The present invention is, therefore, intended to obviate or at least alleviate the problems encountered in the prior art. 
     SUMMARY OF THE INVENTION 
     According to the present invention, a variable-pressure air pump includes a first cylinder and a second cylinder movably connected with one another. The first cylinder defines a first chamber. The second cylinder defines a second chamber fluidly communicable with the outside of the variable-pressure air pump selectively. A plunger has a first end inserted in the first chamber and a second end inserted in the second chamber. The plunger defines a one-way flow passage fluidly connecting with the first and the second chambers. A piston device is configured to compress air in the first and the second chambers. A discharge device includes a connecting member and a switch movably connected with one another. The connecting member defines at least one discharge hole fluidly connecting with the second chamber. The switch has at least one flow guide portion fluidly connecting with the outside of the variable-pressure air pump and at least one blocking portion which is adapted to block the at least one discharge hole. The switch is movable between a first position in which the at least one flow guide portion is adjacent and opens to the at least one discharge hole and a second position in which the at least one blocking portion is adjacent to and blocks the at least one discharge hole. The discharge device is disposed at an end opposite to an end of a head assembly of the variable-pressure air pump. 
     There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. 
     In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. 
     As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
     Further, the purpose of the foregoing abstract is to enable the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure. The abstract is neither intended to define the invention, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way. 
     Other objectives, advantages, and new features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanied drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a variable-pressure air pump in accordance with a first embodiment of the present invention. 
         FIG.  2    is an exploded perspective view of the variable-pressure air pump of  FIG.  1   . 
         FIG.  3    is a cross-sectional view illustrating the operation of the variable-pressure air pump of  FIG.  1   , with a switch thereof in a first position. 
         FIG.  4    is a partial, enlarged cross-sectional view of  FIG.  3   . 
         FIG.  5    is a cross-sectional view taken along line  5 - 5  of  FIG.  4   , with an arrow representing an operational movement. 
         FIG.  6    is a cross-sectional view illustrating the operation of the variable-pressure air pump of  FIG.  1   , with the switch thereof in a second position. 
         FIG.  7    is a partial, enlarged cross-sectional view of  FIG.  6   . 
         FIG.  8    is a cross-sectional view taken along line  8 - 8  of  FIG.  6   . 
         FIG.  9    is a perspective view of a variable-pressure air pump in accordance with a second embodiment of the present invention. 
         FIG.  10    is an exploded perspective view of the variable-pressure air pump of  FIG.  9   . 
         FIG.  11    is a cross-sectional view illustrating the operation of the variable-pressure air pump of  FIG.  9   , with a switch thereof in a first position. 
         FIG.  12    a cross-sectional view illustrating the operation of the variable-pressure air pump of  FIG.  9   , with the switch thereof in a second position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS.  1 - 8    show a variable-pressure air pump in accordance with a first embodiment of the present invention. 
     A cylinder  10  defines a chamber  13  and at least one channel  121  that allows air to flow into the chamber  13 . The cylinder  10  extends longitudinally from an end  11  to an end  12 . The at least one channel  121  extends from the chamber  13 . The at least one channel  121  defines an opening at the end  12 . 
     A cylinder  20  is movably connected with the cylinder  10 . Air in the chamber  13  when the cylinder  20  moves relative to the cylinder  10 . The cylinders  10  and  20  are disposed coaxially and the move relative to one another in an axial direction. The cylinder  20  defines a chamber  23 . The chamber  23  is fluidly communicable with the outside of the variable-pressure air pump selectively. The cylinder  20  is disposed coaxially with the cylinder  10 . The cylinder  20  has an end  21  and an end  22  disposed oppositely. 
     A plunger  30  has an end  31  inserted in the chamber  13  and another end  32  inserted in the chamber  23 . The end  32  is opposite to the end  31 . The plunger  30  defines a one-way flow passage  33  fluidly connecting with the chambers  13  and  23 . 
     A piston device  40  is configured to compress air in the chambers  13  and  23 . The piston device  40  includes a piston  41  configured to compress air in the chamber  13  and a piston  42  configured to compress air in the chamber  23  respectively. The piston  41  is connected with the cylinder  20  and is movably disposed in the chamber  13 . The piston  41  is fixedly connected at the end  21  of the cylinder  20 . The piston  41  moves in the chamber  13  upon relative movement of the cylinders  10  and  20 . The piston  42  is connected with the plunger  30  and movably disposed in the chamber  23 . The piston  42  is fixedly connected at the end  32  of the plunger  30 . The piston  42  moves in the chamber  23  upon relative movement of the cylinders  10  and  20 . 
     A head assembly  50  is configured to engage with an object to be inflated. The head assembly  50  includes a hose  52  and a valve adapter  53  fluidly connecting with one another. The hose  52  is adapted to move between an extended position and a retracted position. The hose  52  is selectively receivable by and fluidly connects with the flow passage  33 . The hose  52  is disposed coaxially with the plunger  30 . The hose  52  and the plunger  30  move relative to one another in an axial direction. The hose  52  is flexible and, therefore facilitates connection of the variable-pressure air pump with an object to be inflated easily and the pumping operation. The valve adapter  53  is configured to connect with an object to be inflated. Specially, the valve adapter  53  can fluidly connect with a valve of the object to be inflated. The head assembly  50  also includes a head  51  adapted to prevent air from flowing therethrough and out of the chamber  13 . The head  51  is connected with the cylinder  10 . The head  51  and the cylinder  10  have threads engaged with one another. The head  51  is also connected with the plunger  30 . The head  51  and the plunger  30  have threads engaged with one another. The piston  42  and the head  51  are connected with the plunger  30  oppositely. Moreover, the head  51  defines a compartment  511  adapted to receive the valve adapter  53  selectively and a compartment  512  with which the end  31  of the plunger  30  is engaged. When the hose  52  is retracted in the flow passage  33 , the valve adapter  53  is stored in the compartment  511 . 
     A discharge device  60  is disposed at an end opposite to an end of a head assembly  50  of the variable-pressure air pump. The discharge device  60  is connected with the cylinder  20 . The discharge device  60  is connected at the end  22  of the cylinder  20 . The connecting member  61  and the cylinder  20  have threads engaged with one another. The discharge device  60  includes a connecting member  61  and a switch  62  movably connected with one another. The switch  62  is fastened to the connecting member  61  by a fastener  63 . The connecting member  61  and the switch  62  respectively defines a hole  613  and a hole  623  and the fastener  63  is inserted through the hole  623  and engaged with the hole  613 . The fastener  63  and the hole  613  have threads engaged with one another. The at least one discharge hole  611  and the hole  613  extend longitudinally parallel to each other. 
     The connecting member  61  and the piston  41  are connected with the cylinder  20  oppositely. The connecting member  61  defines at least one discharge hole  611  fluidly connecting with the chamber  23 . The switch  62  is configured to selectively prevent the chamber  23  from fluidly connecting with the outside of the variable-pressure air pump. The switch  62  has at least one flow guide portion  621  fluidly connecting with the outside of the variable-pressure air pump and at least one blocking portion  622  adapted to block the at least one discharge hole  611 . The switch  62  is movable between a first position in which the at least one flow guide portion  621  is adjacent and opens to the at least one discharge hole  611  and a second position in which the at least one blocking portion  622  is adjacent to and blocks the at least one discharge hole  611 . The air pump can discharge air through the at least one discharge hole  611  when the switch  62  in the first position. The connecting member  61  and the switch  62  have a space therebetween filled by at least one seal  612 . When the at least one blocking portion  622  is adjacent to and blocks the at least one discharge hole  611 , the at least one seal  612  and the at least one blocking portion  622  abut against one another. The at least one discharge hole  611  has a small section  6111  and a large section  6112  and the at least one seal  612  is retained in the large section  6112 . 
     The connecting member  61  has two limits  614  configured to obstruct movement of the switch  62 . The switch  62  in the first position thereof is obstructed by one of the two limits  614 . The switch  62  in the second position thereof is obstructed by the other of the two limits  614 . The switch  62  defines two grooves  624 . The two limits  614  are movably engaged in the two grooves  624  respectively and move therein upon moving the switch  62  with respect to the connecting member  61 . The two limits  614  protrude from an outer surface of the connecting member  61 . The two limits  614  protrude radially from the outer surface of the connecting member  61 . The switch  62  is rotatably connected with the connecting member  61  and each of the two grooves  624  extends curvedly. 
     A shell assembly  70  is configured to be grasped when operating the variable-pressure air pump. The shell assembly  70  includes a sleeve  71  connected with the cylinder  10  and a sleeve  72  connected with the connecting member  61  respectively. The cylinder  10  has a portion disposed outside the sleeve  71  being selectively receivable by the sleeve  72 . The cylinder  20  and the sleeve  72  move together upon moving the cylinder  20  with respect to the cylinder  10 . 
     The shell assembly  70  also includes a cap  711  configured to close an opening of the head assembly  50 . Specifically, the cap  711  is used to close an opening of the compartment  511  of the head  51 . More specifically, the cap  711  can close the opening of the compartment  511  when the valve adapter  53  is stored in the first compartment  511 . The cap  711  and the sleeve  71  are made integrally. Specifically, the cap  711  and the sleeve  71  are made in one piece. 
     A one-way flow device  80  is configured to allow air to flow in one direction and inhibit air passing through from flowing in an opposite direction. The one-way flow device  80  includes a one-way valve  81  disposed between the head  51  and a wall delimiting the inner chamber  13 . The one-way flow device  80  also includes a one-way valve  82  disposed on the piston  42  and within the flow passage  33 . Specifically, the one-way valve  81  is disposed between an outer periphery of the head  51  and an inner wall of the cylinder  10 . 
       FIGS.  9 - 12    show a variable-pressure air pump in accordance with a second embodiment of the present invention, and the same numbers are used to correlate similar components of the first embodiment, but bearing a letter a. The second embodiment is similar to the first embodiment except the followings. A cylinder  10   a  inserted in a cylinder  20   a . The cylinder  10   a  has a first end connected with a head assembly  50   a . A plunger  30   a  is hollow and therefore defines a flow passage  33   a . The plunger  30   a  also defines an orifice  34   a , which extends radially therethrough, fluidly connecting with the flow passage  33   a . The plunger  30   a  has a first end connected with a piston  41   a  and a second end connected with a connector  43   a , which fluidly connects with a discharge device  60   a , which is the same as the discharge device  60 , an thus the descriptions are omitted for the sake of brevity. The connector  43   a  includes at least one discharge hole  431   a  fluidly connecting with at least one discharge hole  611   a  of a connecting member  61   a . A piston  42   a  is connected at a second end of the cylinder  10   a . Additionally, when a switch  62   a  of the discharge device  60   a , which is movably connected with the connecting member  61   a  and fastened thereto by a fastener  63   a , is moved to a first position which allows the pump to discharge air from the discharge hole  611   a , air does not flow into the flow passage  33   a . When the switch  62   a  is in the second position which does not allow the pump to discharge air from the discharge hole  611   a , air flows into the flow passage  33   a . A sleeve  72   a  connected with the cylinder  20   a . The sleeve  72  is disposed adjacent to the discharge device  60   a.    
     In view of the forgoing, when the variable-pressure air pump is operated with the switches  62  and  62   a  being in the first position, the variable-pressure air pump can discharge air to outside through the discharge holes  611  and  611   a . In contrast, when the switches  62  and  62   a  are in the second position, the variable-pressure air pump cannot discharge air to outside through the discharge holes  611  and  611   a.    
     The foregoing is merely illustrative of the principles of this invention, and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.