Air compressors

Abstract

An air compressor may include a compressor unit and an external tank unit connectible with the compressor unit. The external tank unit may include an external tank and a battery. The battery may supply electric power to the compressor unit.

What is claimed is: 
     
         1 . An air compressor comprising:
 a compressor unit configured to supply compressed air to a pneumatic tool; and   an external tank unit connectible with the compressor unit;   wherein the external tank unit includes:   an external tank capable of storing the compressed air; and   a first battery configured to supply electric power to the compressor unit.   
     
     
         2 . The air compressor according to  claim 1 , wherein the compressor unit includes an air-compressing device and a second battery serving as a power source for driving the air-compressing device. 
     
     
         3 . The air compressor according to  claim 2 , wherein the first battery and the second battery can be used interchangeably for supplying electric power to the air-compressing device. 
     
     
         4 . The air compressor according to  claim 1 , wherein the external tank unit includes a battery charger capable of charging the first battery. 
     
     
         5 . The air compressor according to  claim 1 , wherein the external tank unit is configured to be able to connect an electric device that is a different device from the compressor unit, so that electric power can be supplied from the first battery to the electric device. 
     
     
         6 . The air compressor according to  claim 1 , wherein the first battery is removably mounted to the external tank unit. 
     
     
         7 . A compressor unit used for a pneumatic tool and connectible with an external tank unit having a first storage tank and a first battery, the compressor unit comprising:
 an air-compressing device configured to be electrically driven;   a second battery serving as a power source for driving the air-compressing device;   a second storage tank capable of storing compressed air;   an input terminal electrically connected to the air-compressing device and connectible with the first battery of the external tank unit, so that the air-compressing device can be driven by electric power supplied from the first battery of the external tank; and   an air coupler connectible with the external tank, so that compressed air produced by the air-compressing device can be stored in both the first storage tank of the external tank unit and the second storage tank of the compressor unit for driving a pneumatic tool.   
     
     
         8 . The compressor unit according to  claim 7 , wherein the air coupler is also connectible with the pneumatic tool. 
     
     
         9 . An external tank unit connectible with a compressor unit used for a pneumatic tool, comprising:
 a storage tank configured to store compressed air produced by the compressor unit; and   a battery configured to supply electric power to the compressor unit.   
     
     
         10 . The external tank unit according to  claim 9 , wherein the external tank unit further includes an air coupler connectible with a pneumatic tool.