Revolvable quick coupling

For connecting an air compressor to a pneumatic tool, a revolvable quick coupling comprising a first air pipe connector revolvably secured to an intermediate connecting member by a ball bearing means and connected to an air output pipe of an air compressor, a second air pipe connector secured to said intermediate connecting member by a front socket, a retainer, an inner socket, a seal ring, a stepped metal element and a spring means for connecting to an air input pipe of a pneumatic tool. Pressing on the retainer causes the second air pipe connector to disconnect from the front socket and simultaneously causes said seal ring to seal the air passage inside the coupling. Rotating the pneumatic tool causes the second air pipe connector to rotate on the first air pipe connector without twisting the air output pipe of the air compressor.

BACKGROUND OF THE INVENTION 
The present invention relates to quick couplings and relates more 
particularly to a revolvable quick coupling for connecting an air pipe 
from an air compressor to a pneumatic tool, which automatically seal off 
the air passage therein once a pneumatic tool is detached and, which 
follows a pneumatic tool to rotate on a second air pipe connector without 
twisting the air pipe from of the connected air compressor. 
Various quick connectors have been known and used in connecting air 
compressors to pneumatic tools. However, the known quick connectors are 
not satisfactory in use because neither one of them can be rotated by a 
pneumatic tool. If a quick connector is rotated by a pneumatic tool, the 
air pipe which is connected thereto will be twisted and damaged causing 
air leakage problem. The present invention has been accomplished to 
eliminate this problem. 
SUMMARY OF THE INVENTION 
According to the present invention, there is provided a revolvable quick 
coupling comprised of a first air pipe connector revolvably secured to an 
intermediate connecting member by a ball bearing means and connected to an 
air output pipe of an air compressor, a second air pipe connector secured 
to the intermediate connecting member by a front socket, a retainer, an 
inner socket, a seal ring, a stepped metal element and a spring means for 
connecting to an air input pipe of a pneumatic tool, wherein pressing on 
the retainer causes the second air pipe connector to disconnect from the 
front socket and simultaneously causes the seal ring to seal the air 
passage inside the coupling; rotating the pneumatic tool causes the second 
air pipe connector to rotate on the first air pipe connector without 
twisting the air output pipe of the air compressor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIGS. 1, 2, 3 and 4, a rear socket 11 has an annular groove 
114 at the inside for holding a plurality of rolling balls 111. A rotary 
ring 112 is supported on the rolling balls 111 inside the rear socket 11. 
The rotary ring 112 has an annular groove 1122 on a bottom edge thereof 
for holding the rolling balls 111, and a center hole 1121 through the 
central axis thereof for inserting a rear air pipe connector 12. The rear 
air pipe connector 12 has two annular grooves 121, 122 with one 121 rising 
behind the other 122. The annular groove 121 is inserted through the rear 
socket 11 and the center hole 1211 of the rotary ring 112 and secured in 
place by a C-shaped retainer ring 113. The rear socket 11 is mounted on an 
intermediate connecting member 13 at one end. A rubber ring 131 is 
inserted into the intermediate connecting member 13 and sleeved onto the 
front annular groove 122 of the rear air pipe connector 12 to seal the gap 
between the rear air pipe connector 12 and the intermediate connecting 
member 13. A movable stepped metal element 133 which has an air hole 1331 
is inserted into the intermediate connecting member 13 and supported on a 
spring 132 therein. An inner socket 14 is mounted on the intermediate 
connecting member 13 at its opposite end to hold the stepped metal element 
133 and the spring 132 inside the intermediate connecting member 13. A 
ring-shaped rubber insert 141 which has a center hole 1411 through the 
central axis thereof is inserted inside the inner socket 14 and sleeved on 
the stepped metal element 133 to seal the air hole 1331. A retainer 152 is 
positionally located and slidable within a grove 151 formed in a front 
socket 15 and supported on a spring 153 retained therein. The retainer 152 
which is supported on the spring 153 has an oval hole 1522 through the 
center thereof and a stub rod 1521 at one end. The stub rod 1521 of the 
retainer 152 is constantly extended out of the pivot hole 151. There is 
also provided a front air pipe connector 16 which has a tapered terminal 
161 at one end and an annular groove 162 at a suitable location. Inserting 
the tapered terminal 161 of the front air pipe connector 16 through a 
center hole 1511 on the front socket 15 causes the oval hole 1522 to 
retain the annular groove 162, and therefore, the front air pipe connector 
16 becomes firmly secured to the quick coupling 1. At the same time, the 
stepped metal element 133 is pushed backwards by the tapered terminal 161 
of the front air pipe connector 16 causing the air hole 1331 to move away 
from the ring-shaped rubber insert 141, and therefore, a flow of gas is 
permitted to pass through the air hole 1331 into the front air pipe 
connector 16. Pressing the stub rod 1521 of the retainer 152 causes the 
front air pipe connector 16 to be released from the constraint of the oval 
hole 1522 on the retainer 152, and therefore, the front air pipe connector 
16 is immediately pushed out of the quick coupling 1 by the spring 132 and 
the stepped metal element 133. Once the front air pipe connector 16 is 
disconnected from the quick coupling 1, the stepped metal element 133 is 
simultaneously moved into the center hole 1411 of the ring-shaped rubber 
insert 141, and therefore, the air hole 1331 is sealed up again to stop 
the flow of gas from passing therethrough. When a pneumatic tool 3 is 
connected to the front air pipe connector 16, a flow of compressed air can 
be guided from a compressor (not shown) through an air pipe into the 
pneumatic tool 3 for operation. Rotating the pneumatic tool 3 causes the 
front air pipe connector 16 to rotate relative to the rear air pipe 
connector 12, and therefore, the air pipe 2 will not be twisted or damaged 
(see FIG. 5).