Quick connector with variable length compensation

In a quick-fitting pipe union for sealingly connecting two pipes (1 and 4) comprising an annular cage (8) fitted on the outer side of the one pipe (4) and fitted inside with an annular helical spring (9). When the pipes (1 and 4) are slid axially into one another, the spring latches over a flange (2) of the receiving pipe (1). The annular cage (8) with the sealing means (6/7) is fitted after the enlargement (5) is loosely slidable relative to the receiving pipe.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to a quick-fitting pipe union for sealingly 
connecting two pipes. More particularly, the present invention relates to 
a quick connect fitting comprising an annular cage with an annular helical 
spring fitted on the outer side of one pipe which, when slid axially into 
another pipe, latches over a flange and connects the two pipes together. 
2. Disclosure Information 
German patent specification DE 26 52 207 discloses a quick-fitting pipe 
union for sealingly connecting two pipes comprising a cage fitted on the 
outer side of the one pipe and having an annular helical spring fitted 
therein which serves to hold the second pipe on a flange when the pipes 
are slid into one another. The seal between the two telescoped pipes is 
obtained by an O-ring arrangement, and by means of the cage, which in this 
known quick-fitting union is fixed axially on one pipe, the two pipes are 
also secured against accidental separation from one another. This type of 
quick-fitting pipe union is also know as a spring lock coupling. 
Quick-fitting pipe unions of this kind are increasingly being used in motor 
vehicles to connect the various coolant pipelines of air-conditioning 
installations. Accordingly, when there are several models of vehicle a 
large number of corresponding sections of pipe with corresponding 
quick-fitting pipe unions have hitherto had to be stocked to provide for 
the necessary adaptation to the fitting space. 
The invention proceeds from the observation that many such pipe components 
which have to be stocked only differ from one another by small differences 
in length, and that as a rule, in fitting these pipe components in the 
vehicle, after assembly has been completed, with the necessary adjustments 
in length, the pipe components are fixed in such a way that accidental 
axial separation is hardly possible. The risk of complete separation after 
the maximum adjustment of length has taken place is reduced by the 
enlargement of the inserted pipe. 
The object of the invention is therefore to modify the known quick-fitting 
pipe union in such a way so as to provide a considerable amount of length 
adjustment. 
SUMMARY OF THE INVENTION 
According to the invention this object is achieved in a quick-fitting pipe 
union of the kind referred to above having an annular cage fitted on the 
one pipe and carrying the annular helical spring which is loosely axially 
slidable on the outer circumference of the pipe. 
Since the quick-fitting pipe union of the invention makes a considerable 
adjustment in length possible when connecting two pipes, the total number 
of different pipe components which have to be stocked, e.g. for the 
installation of an air-conditioning plant in a motor vehicle, can be 
considerably reduced.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
As shown in FIGS. 1 and 2, the union of two pipes comprises a receiving 
pipe 1 having at its free end a flange 2 and can optionally be provided 
further along with a narrower portion 3. 
The entering pipe 4 is provided at its free end with an enlargement 5, in 
which grooves 6 are formed, generally by a special upsetting process, to 
receive conventional O-ring seals 7. 
The external diameter of the enlargement 5 fits into the internal diameter 
of the receiving pipe 1 with a sliding fit. 
Starting from the end of the entering pipe 4, after its enlargement 5, an 
axially slidable cage 8 is fitted on the pipe 4 which in known manner 
accommodates an annular helical spring 9. The annular cage 8 has an inlet 
opening 10, the diameter of which allows the unhindered entry of the 
flange 2 of the receiving pipe 1. The other diameter 11 of the annular 
cage 8 is only slightly larger than the external diameter of the pipe 4 
and is a loose sliding fit thereon. This allows the cage 8 to slide 
axially along the length of the pipe 4. 
Once the two pipes 1 and 4 have been slid axially into one another as shown 
in FIG. 2, the enlargement 5 can assume various axial positions within the 
receiving pipe 1 (one position being indicated in broken lines and another 
possible position in chain lines). By pushing the annular cage 8 over the 
flange 2 of the pipe 1 locking of the two pipes 1 and 4 is obtained 
insofar as the annular cage 8 is now connected to the pipe 1 by the 
outwardly expanded helical spring 9 and can only be separated from it by 
the use of a special tool. Furthermore, complete pulling apart is reliably 
prevented by the cage 8 coming to bear on the enlargement 5. 
Unintended change in length of the two pipes can be prevented by the 
securing clip mentioned in German patent DE 19 513 058, corresponding to 
U.S. Pat. No. 5,738,384, assigned to the assignee of the present 
invention, the disclosure at column 2, line 15 to column 3, line 7 is 
hereby incorporated by reference. 
Various modifications to the present invention will no doubt become 
apparent to those skilled in the art. It is the following claims, 
including all equivalents, which define the scope of my invention.