Method of forming attachment of a hose to a fitting

An assembly for attaching a new hose to an existing fitting includes an expandable split ring having an internal diameter less than the diameter of a preformed radially outwardly extending annular wall on the fitting, and a collar that is positionable over the fitting and the expandable split ring. The collar has a radially inwardly extending wall portion and a deformable sleeve portion. The split ring is positionable adjacent the annular wall on the fitting, and the radially inwardly extending wall portion of the collar is positionable in an abutting relationship with the expandable split ring. The deformable sleeve portion of the collar is inwardly deformable to provide retention of the collar, split ring, and hose on the fitting. The present invention solves the problem of the need for new fittings when modifying existing refrigeration systems to accept new refrigerants.

BACKGROUND OF THE INVENTION 
1. Technical Field 
This invention relates generally to an assembly and method of using the 
assembly to attach a hose to a fitting, and more particularly to such an 
assembly and method directed to the replacement of hose on prevailing 
fittings. 
2. Background Art 
Recently imposed governmental regulations limit, or prohibit entirely, the 
production of ozone-depleting refrigerants such as R12 freon previously 
used in automotive air conditioning systems. New refrigerants have been 
developed and approved for use, but are not compatible with the hose and 
seal components of the older systems. New hose and seal materials and 
hose-to-fitting attachment arrangements, compatible with recently approved 
refrigerants, specifically R134A refrigerant, have been developed. Thus, 
at the present time two distinct and noncompatible refrigerant systems are 
in general use, heretofore requiring automotive air conditioning service, 
repair, or conversion facilities to maintain a large inventory of hoses 
and fittings for each system. 
Exacerbating the problem of incompatible material components for the two 
refrigerant systems is the practice of using barbed tubes on the ends of 
the fittings in the older R12 system to provide retention of the hose on 
the tube end of the fitting. The molecular structure of the currently 
approved R134A refrigerant is much smaller than R12, and requires that 
hoses have an impermeable barrier layer, such as teflon, to prevent the 
loss of refrigerant through the wall of the hose. If the older fittings 
are used with new barrier layer hoses, the barbs on the tube ends 
perforate the barrier layer and destroy the sealing capability of hose. 
To overcome this problem, either new fittings without barbed tube ends or 
modification of the old fittings by cutting off the barbed tube ends has 
been required. New fittings, while desirable, requires that a service or 
repair facility maintain a large inventory of fittings to satisfy the 
size, connection and configuration requirements of each original equipment 
and after-market manufacturer. This practice is prohibitively expensive, 
especially for smaller garages and shops, and new hose assemblies are not 
always available for older vehicles. 
As described above, the older fittings have been reused by cutting off the 
barbed tube end of the fitting. This practice then requires that a new 
tube end be welded to the fitting, or that a specifically designed 
multiple component threaded adapter be secured to the remaining fitting. 
If welded, the services of a certified welder are required. Suitable 
adapters typically require that a ferrule be secured to the fitting after 
which a complex assembly comprising an o-ring seal, a connector body 
threaded at both ends, a tube nut, a hose nut, and a special barbed hose 
compression ring are assembled together. Since, the connecting end of 
fittings are not standardized, the use of adapters to reuse old fittings 
also requires a prohibitively large inventory of adapter components. 
The present invention is directed to overcoming the problems set forth 
above. It is desirable to have an assembly whereby new hoses can be 
assembled on previously used fittings without cutting off the tube end of 
the fitting. It is also desirable to have a method of replacing the hose 
on a fitting without requiring welding or the use of complex, multiple 
component adapters. It is also desirable to have such an assembly that is 
economical and a method that is readily carried out with tools that are 
commonly available in a typical automobile air conditioning repair or 
service facility. 
SUMMARY OF THE INVENTION 
In accordance with one aspect of the present invention, an assembly for 
attaching a hose to a fitting includes an expandable ring having an 
internal diameter substantially equal to a predefined outer diameter of 
the fitting at a position adjacent a radially outwardly extending annular 
wall having a predefined outer diameter. The expandable ring has an outer 
diameter substantially equal to the outer diameter of the hose. The 
assembly also includes a collar having a deformable annular sleeve portion 
and a radially inwardly deformable wall portion disposed at one end of the 
sleeve portion. The deformable sleeve portion has an inner diameter 
substantially equal to the outer diameter of the hose, and the radially 
inwardly extending wall has an inner diameter greater than the predefined 
outer diameter of the radially outwardly extending annular wall of the 
fitting. 
Other features of the assembly, comprising the present invention, for 
attaching a hose to a fitting include the expandable ring being a C-clip, 
the deformable annular sleeve of the collar having a plurality of slots 
extending through predefined portions of the sleeve at a position 
proximate an end of the sleeve spaced from the radially inwardly extending 
wall of the collar, and the radially inwardly extending wall of the collar 
having an opening formed at a predefined position in said wall. 
In accordance with another aspect of the present invention, a method of 
attaching a hose to a fitting having at least one radially outwardly 
extending annular wall disposed intermediate the connection and tube ends 
of the fitting, includes installing a collar, having a deformable sleeve 
with an inner diameter substantially equal to the outer diameter of the 
hose and a radially inwardly extending wall at one end, over the tube end 
of the fitting, and moving the collar past the radially outwardly 
extending annular wall of the fitting to a position between the annular 
wall and the connection end of the fitting, with the inwardly extending 
wall of the collar facing the connection end of the fitting. An expandable 
ring, having an inner diameter substantially equal to the outer diameter 
of the fitting, is then inserted onto the fitting at a position adjacent 
the annular wall between the previously installed collar and the annular 
wall. A hose is then pushed onto the tube end of the fitting a distance 
sufficient to position the end of the hose adjacent the annular wall of 
the fitting. The deformable collar is then drawn towards the tube end of 
the fitting until the radially inwardly extending wall of the collar abuts 
the prepositioned expandable ring, the expandable ring abuts the annular 
wall of the fitting, and the deformable sleeve extends over a predefined 
portion of the hose. The assembled fitting, ring, collar and predefined 
portion of the hose is then placed in a press having predefined die 
elements disposed therein, and the die elements brought together at a 
predetermined rate and pressure whereby the sleeve of the collar is 
radially inwardly deformed to retain the hose and form an impermeable seal 
against the tube end of the fitting. 
Other features of the method for attaching the hose to the fitting include 
radially orienting the collar with respect to the die members of the press 
to form, upon closure of the die members, longitudinal grooves in the 
deformable sleeve that extend from a position spaced from the radial wall 
end of the collar to an end of the collar spaced from the radial wall end, 
in radial alignment with a plurality of slots formed in the sleeve.

DETAILED DESCRIPTION OF THE INVENTION 
An assembly for attaching a hose 12 to a fitting 14 is generally identified 
in FIG. 1 by the reference number 10. The assembly 10 includes an 
expandable ring 16, such as a conventional C-clip as shown in FIG. 2, and 
a collar 18. The fitting 14 typically has a forward, or component 
attachment, end 20 that has a face adapted to mate with a port on a 
compressor, condenser, or other element of an air conditioning system, and 
a nut adapted to mate with and attachably connect the fitting to the 
element. These components are generally arranged for a specific 
installation, and for the sake of clarity, are not shown in the drawings. 
The opposite, i.e., the rear or hose attachment, end 22 of the fitting 14 
is adapted for attachment with the hose 12, and typically has one of four 
standard diameters adapted to receive 5/16", 13/32", 1/2", or 5/8" I.D. 
hoses, commonly identified respectively as Nos. 6, 8, 10 or 12 size hoses. 
The fitting 14 also typically has at least one, and often two, outwardly 
extending annular walls 24 usually formed by upsetting. The upset annular 
walls 24 provide what is known as a bead lock rings which, in the original 
structure, provides a forming surface against which a collar is crimped to 
provide retention of the hose on the fitting. 
The present invention advantageously uses one of the bead lock rings 24 as 
a longitudinal reaction surface to prevent the rearward movement of the 
expandable ring 16 after it is installed on the fitting 14. The expandable 
ring 16 has an internal diameter that is less than the outer diameter of 
the annular wall 24 of the fitting 14 and is substantially equal to the 
diameter of the fitting 14 adjacent a single bead lock ring 24, or between 
a pair of bead lock rings 24 in double-upset ring arrangements. The 
expandable ring 16 is desirably a conventional C-clip, or has a 
construction similar to a conventional C-clip, as illustrated in FIG. 2. 
Thus, the expandable ring 16 can be installed on the fitting 14 by opening 
the mouth of the ring 16 and sliding it transversely over the outer 
surface of the fitting 14. The inner diameter of the expandable ring 16 is 
preferably equal to the outer diameter of the fitting 14 adjacent the 
upset rings 24, and the outer diameter of the expandable ring 16 is 
desirably equal to or, for ease of assembly, slightly less (for example, 
about 0.005") than the outer diameter of the hose 12. 
The collar 18, preferably formed of steel, has a deformable sleeve portion 
26 extending rearwardly from a radially inwardly extending wall 28 
disposed at the forward end of the collar 18. The sleeve portion 26 has an 
inner diameter substantially equal to the outer diameter of the hose 12. 
The inner diameter of the radially inwardly extending wall 28 is 
preferably slightly greater, for example on the order of about 0.010 inch, 
than the outer diameter of the upset annular walls 24 of the fitting 14, 
to permit free passage of the collar 16 over the walls 24. 
If it is desired to use the crimping dies commonly used on the previous R12 
systems, one or more slots 30 are preferably provided in the wall of the 
sleeve portion 26 at a position near the rearward end of the sleeve 
portion 26. When crimped by the forming dies commonly used on R12 
fittings, a plurality of inwardly extending longitudinally directed 
grooves 32 are formed in the sleeve, as shown in FIGS. 3, 4 and 5. 
Desirably, the collar 18 is oriented in the crimping die so that the 
bottom, or deepest portion, of the grooves 32 correspond with the slots 30 
which permit a small portion of the outer surface of the hose 12 to be 
deformed outwardly into the slots, thereby providing secure retention of 
the collar 18 to the hose 12, and assure sealing engagement of the hose 12 
with the tube end 22 of the fitting 14. Desirably, four slots, each 
measuring about 0.4" by 0.2" are positioned so that they are spaced apart 
at 90.degree. arcuate intervals at the bottom of the longitudinal grooves 
26 after crimping. To provide an index for alignment of the slotted collar 
18 with the dies in the crimping press, and provide a visual inspection 
port to assure proper positioning of the expandable ring 16 and end of the 
hose 12 within the collar 18, a small slot or opening 34 is desirably 
provided at a predetermined position in the radially inwardly extending 
wall 28 of the collar 14. 
If desired, the deformable sleeve 26 of the collar 14 may be crimped by 
dies typically used in conjunction with the newer R134A systems which form 
what is generally known as a "bubble crimp" This type of crimp forms a 
plurality of inwardly deformed radial rings in the sleeve 26 which secure 
the collar 14 to the hose 12 with sufficient force to seal the hose 12 
around the tube end 22 of the fitting 14. In this arrangement, the slots 
30 in the sleeve 26 are generally not required. 
In carrying out the method of attaching a hose to a fitting by use of the 
above described assembly 10, if old fittings are to be reused, the factory 
bead lock collar should be carefully removed to as not to damage the 
fitting. This can be done by cutting, preferably without the use of 
cutting torches or other thermal cutting devices. The cutting can be 
accomplished by conventional metal cutting tools such as a hack saw or 
high speed rotary cutter. On hose assemblies where the original collar was 
welded to the tube, the front or welded portion of the collar is ground 
and sized to provide an anchorage point for the expandable ring 16 and the 
new collar 18. Once the old collar is removed, the old hose is cut away 
from the fitting. 
The reclaimed fitting 14 should be cleaned and inspected for damage, 
cracks, scratches and the like, and then measured to determine if resizing 
is required. Resizing, if required, is easily carried out using the 
external sizing dies or internal expansion dies of a conventional expander 
tool. 
The reclaimed fitting 14 is now ready for attachment to a hose 12 of the 
required composition in accordance with the method embodying the present 
invention, as illustrated diagrammatically in FIG. 6. First, as 
represented by block 40, the collar 18 is installed onto the fitting 14. 
This is accomplished by inserting the collar 18, inwardly extending wall 
28 first, over the tube end 22 of the fitting 14, and then sliding the 
collar 18 forward over the upset annular wall, or walls, 24 to a position 
forward of the wall 24. Next, as indicated at block 42, the expandable 
ring 16 is inserted over the outer surface of the fitting 14 a position 
between the annular walls 24 if there are two walls, or adjacent the 
forward face of a single annular wall 24. As indicated at block 44, the 
hose 12 is then inserted over the tube end 22 of the fitting 14 and pushed 
onto the fitting 14 until the hose end abuts the rear surface of the 
annular wall 24. The assembly 10 and the hose 12 are then longitudinally 
aligned with the fitting 14, as indicated at block 46, by pulling the 
collar 18 rearwardly over the expandable ring 16 and the hose 12 until the 
inwardly extending wall 28 at the forward end of the collar 18 abuts the 
expandable ring 16. Correct positioning of the collar 18, the expandable 
ring 16, and end of the hose 12 with respect to the upset annular wall 24 
of the fitting 14 can be assured by visual observation of the respective 
components through the inspection port 34. If longitudinal crimping dies 
are used for crimping the collar 18, the collar 18 should be rotated, as 
indicted at optional block 48, until the desired orientation of the slots 
30 with respect to the crimping dies is achieved. 
After alignment, the assembled collar 18, expandable ring 16, hose 12 and 
fitting 14 are placed in the crimping die and the die closed, as 
represented at block 50. Upon closure, the inwardly extending wall 28 of 
the collar 18 is crimped against the outer surface of the fitting 14. The 
inward deformation of portions of the deformable sleeve 26 form the 
longitudinal grooves 32 and compresses the hose 12 between the sleeve 26 
and the fitting 14 to form a gas-tight seal between the hose 12 and the 
fitting 14 and provide retention of the hose 12 on the fitting 14. After 
crimping, the assembled hose 12 and fitting 14, containing the split ring 
16 and collar 18, are removed from the die, and is ready for installation 
in an air conditioning system. 
If a compact, portable press and die arrangement is used, the assembly of a 
new hose 12 to a fitting 14 connected to a system component, such as a 
compressor, may be carried out, in situ, in accordance with the present 
invention without detaching the fitting 14 from the system component. 
Thus, it can be seen that the present invention provides an economical, 
relatively simple and efficient way to reuse fittings in automotive air 
conditioning systems, regardless of the previous refrigerant used in the 
system. Only four differently sized collars 18, and four differently sized 
expandable rings 16 are required to service fittings for all four hose 
sizes, regardless of fitting configuration. 
If desired, the collar 18 may be conveniently formed by modification of the 
R12 system collars previously in widespread use. Such modification would 
only require that the inside diameter of the inwardly extending wall 28 of 
the collar 18 be expanded to provide clearance over the upset annular wall 
24 of the fitting 14, and the provision of an inspection port 34 in the 
inwardly extending wall 28. If used in the longitudinal crimp 
configuration, the slots 30 should also be formed in the sleeve portion 26 
of the collar 18. 
Although the present invention is described in terms of illustrative 
examples and embodiments, those skilled in the art will recognize that 
changes in the illustrative examples may be made without departing from 
the spirit of the invention. Such changes are intended to fall within the 
scope of the invention. Other aspects, features and advantages of the 
present invention can be obtained by a study of the drawings and this 
disclosure.