Air compressor

#1. Field of the Invention

#This invention relates to an air compressor, particularly to one composed of a machine base, a transmission device, a cylinder, a valve body, an automatic pressure-releasing valve and a manual pressure-releasing valve. The transmission gear of the transmission device is driven by a motor to rotate and actuate a subordinate gear to rotate together with a cam, which, by its eccentric acceleration of gravity, makes a connecting rod and a piston move up and down repeatedly in the cylinder. When the piston rod together with the piston is moved downward, air will get into the cylinder through the air hole of the piston; when the piston is moved upward, air in the cylinder will be compressed to get into the valve body, and then exhaust out of the valve body through an air outlet and be guided by an air duct to be pumped into the tyre, thus the pressure of the exhausted air being very steady. Besides, when the pressure gauge of the air compressor indicates that the air pressure is excessive, surplus pressure can be released by the automatic pressure-releasing valve or by the manual pressure-releasing valve so as to protect the components inside the air compressor from damaged and ensure safety of a tire receiving compressed air from the air compressor.

#2. Description of the Prior Art

#This invention will be better understood by referring to the accompanying drawings, wherein:

#FIG. 1 is a cross-sectional view of a conventional air compressor, indicating air sucked into a cylinder;

#FIG. 2 is a cross-sectional view of the conventional air compressor, indicating air compressed and exhausted out of the cylinder;

#A preferred embodiment of an air compressor in the present invention, as shown in FIGS. 3 and 4, includes a machine base 2, a transmission device 3, a cylinder 4, a valve body 5, an automatic pressure-releasing valve 6 and a manual pressure-releasing valve 7 as main components combined together.

#The machine base 2 has a chamber 20 formed in the interior, a through opening 21 bored in the topside to communicate with the chamber 20 and a plurality of fixing studs 22 provided around the outer circumference of the through opening 21 and respectively having a threaded hole 220. The machine base 2 is further provided at one side with a vertical opening 23 defined by two opposite side walls respectively formed with a shaft hole 24, with a recess 25 provided at the outer side of each shaft hole 24 for receiving a bearing 250 therein. A motor seat 27 is secured on one upper side of the machine base 2, having a horizontal shaft hole 28 formed inside and two fixing holes 29 respectively bored at the opposite sides of the shaft hole 28 for bolts 290 to be inserted therethrough.

#The transmission device 3 is composed of a motor 30, a transmission gear 31, a subordinate gear 32, a cam 33, an eccentric shaft 34, a piston rod 35, a piston 36, a cover 37, a piston air ring 38 and a gasket 39. The motor 30 is fixedly assembled on the motor seat 27 of the machine base 2 by the bolts 290. The transmission gear 31 is fixed on the shaft 301 of the motor 30 and positioned in the through hole 26 of the machine base 2. The subordinate gear 32 is inserted by a transmission shaft 320 and received in the vertical opening 23 of the machine base 2 meshing with the transmission gear 31. The cam 33 is secured on one end of the transmission shaft 320 and received in the chamber 20 of the machine base 2. The cam 33 has a shaft hole 330 in the center and an insert hole 331 under the shaft hole 330 for an eccentric shaft 34 to be fixed therein. The piston rod 35 is bored with an accommodating hole 351 at the lower end for receiving a bearing 350, which is fixed on the eccentric shaft 34. The piston 36 assembled on the piston rod 35 is provided at the topside with an air hole 360 and two studs 361. The cover 37 disposed on the piston 36 is bored in the topside with two insert holes 370 and a C-shaped hole 371 having a stop sheet 372 defined by the C-shaped hole 371 for covering the air hole 360 of the piston 36. The piston air ring 38 is fixed on the upper side of the piston 36 for the gasket 39 to be fitted therein.