Air pump

Abstract

An air pump has a main frame, at least one pressure cylinder, a footboard, a torsion spring, a holding device, an outlet device, and an inflating tube. The main frame has a first connecting shaft, a pivot shaft, and a second connecting shaft. The at least one pressure cylinder is mounted in the main frame, and each one of the at least one pressure cylinder has a cylinder and a cylinder axis. The footboard is connected to the pivot shaft. The torsion spring is mounted around the pivot shaft and is pressed against the footboard and the first connecting shaft. The holding device is connected to the main frame and the at least one pressure cylinder, and has multiple first holding elements. The outlet device is mounted in the main frame and is connected to the at least one pressure cylinder. The inflating tube is connected to the outlet tube and is held with the holding device.

What is claimed is: 
     
         1 . An air pump comprising:
 a main frame having:
 a front end; 
 a rear end; 
 a pivot shaft transversally connected to the front end of the main frame; 
   a first connecting shaft transversally connected to the main frame proximal to the front end of the main frame and being parallel with the pivot shaft; and   a second connecting shaft transversally connected to the main frame proximal to the rear end of the main frame;   at least one pressure cylinder mounted in the main frame, and each one of the at least one pressure cylinder having
 a cylinder movably mounted in the main frame; and 
 a cylinder axis connected to the cylinder, connected securely to the second connecting shaft, and having
 an inner end mounted in the cylinder; and 
 an outer end securely connected to the second connecting shaft of the main frame; 
 
   a footboard connected to the pivot shaft of the main frame to enable the footboard to rotate relative to the main frame and to be securely connected to the cylinder of the at least one pressure cylinder;   at least one torsion spring mounted around the pivot shaft of the main frame, and each one of the at least one torsion spring having two ends each respectively pressed against the footboard and the first connecting shaft of the main frame;   a holding device connected to the main frame and having multiple first holding elements, and each first holding element having
 a first body securely mounted on the first connecting shaft and having
 a top; 
 a bottom; 
 a front side; and 
 a first holding recess formed in the bottom of the first body; 
 
   an outlet device mounted in the main frame, connected to the at least one pressure cylinder, and communicating with the cylinder of the at least one pressure cylinder, and the outlet device having an outlet tube extending over the first connecting shaft; and   an inflating tube connected to the outlet tube, mounted in the main frame, and held with the holding device, and the inflating tube having
 a connecting end mounted around the outlet tube of the outlet device and communicating with the cylinder of the at least one pressure cylinder via the outlet device; and 
 an inlet end extending across the pivot shaft and extending through the holding recesses of the first holding elements to enable the inflating tube to be held in the main frame in an annular configuration by the holding device. 
   
     
     
         2 . The air pump as claimed in  claim 1 , wherein the first body of each one of the first holding elements has a first assembling recess formed in the top of the first body and mounted around the first connecting shaft. 
     
     
         3 . The air pump as claimed in  claim 2 , wherein each first holding element has an auxiliary arm formed on and protruding from the front side of the first body of the corresponding first holding element, and the auxiliary arm having:
 a free end extending below the pivot shaft between the main frame and the footboard, and having a top surface; and   a locating recess formed in the top surface of the free end of the auxiliary arm and mounted around the pivot shaft to prevent the first holding element from rotating relative to the main frame.   
     
     
         4 . The air pump as claimed in  claim 1 , wherein the holding device has at least one second holding element mounted around the second connecting shaft of the main frame, and each one of the at least one second holding element having:
 a second body being S-shaped and having
 a top; 
 a bottom; 
 a front side; 
 a rear side; and 
 a second holding recess formed in the rear side of the second body proximal to the bottom of the second body to hold the inflating tube with the main frame. 
   
     
     
         5 . The air pump as claimed in  claim 2 , wherein the holding device has at least one second holding element mounted around the second connecting shaft of the main frame, and each one of the at least one second holding element having:
 a second body being S-shaped and having
 a top; 
 a bottom; 
 a front side; 
 a rear side; and 
 a second holding recess formed in the rear side of the second body proximal to the bottom of the second body to hold the inflating tube with the main frame. 
   
     
     
         6 . The air pump as claimed in  claim 3 , wherein the holding device has at least one second holding element mounted around the second connecting shaft of the main frame, and each one of the at least one second holding element having:
 a second body being S-shaped and having
 a top; 
 a bottom; 
 a front side; 
 a rear side; and 
 a second holding recess formed in the rear side of the second body proximal to the bottom of the second body to hold the inflating tube with the main frame. 
   
     
     
         7 . The air pump as claimed in  claim 4 , wherein the second body of each one of the at least one second holding element has
 a second assembling recess formed in the front side of the second body proximal to the top of the second body above the second holding recess, and mounted around the second connecting shaft of the main frame; and   a connecting hole formed through the rear side of the second body, communicating with the second assembling hole, and mounted around the cylinder axis of the at least one pressure cylinder.   
     
     
         8 . The air pump as claimed in  claim 5 , wherein the second body of each one of the at least one second holding element has
 a second assembling recess formed in the front side of the second body to the top of the second body above the second holding recess, and mounted around the second connecting shaft of the main frame; and   a connecting hole formed through the rear side of the second body, communicating with the second assembling hole, and mounted around the cylinder axis of the at least one pressure cylinder.   
     
     
         9 . The air pump as claimed in  claim 6 , wherein the second body of each one of the at least one second holding element has
 a second assembling recess formed in the front side of the second body proximal to the top of the second body above the second holding recess, and mounted around the second connecting shaft of the main frame; and   a connecting hole formed through the rear side of the second body, communicating with the second assembling hole, and mounted around the cylinder axis of the at least one pressure cylinder.