Flexible pipe coupler

A coupler for interconnecting in fluid communication a pair of axially aligned flexible pipe ends, employs a tubular member for insertion between two sections of drainpipe to be coupled. A first thread is included on a first end portion of the tubular member for threaded engagement of a first one of the two sections of drainpipe, along with a second thread on a second end portion for threaded engagement of the second section. An integrally formed annular flanges in one form of the invention serves as a grip with which to manually screw the tubular member onto the drainpipe, while a cutback portion on the flange prevents misalignment of the coupled sections at the coupling when placed upon the ground. Tapered end pieces that screw onto each end to accommodate smaller drainpipe are provided in another form, with the threads of the tubular member matching the helically-corrugated plastic casing surface of conventional RV drainpipe.

TECHNICAL FIELD 
This invention relates generally to flexible pipe couplers, and more 
particularly to a coupler for corrguated drainpipes commonly employed by 
recreational vehicles. 
BACKGROUND ART 
Recreational vehicles vastly improve outdoor life. Like a small cabin on 
wheels, they house many convenient living accommodations, while providing 
the mobility that enables rapid transformations from city to country life. 
Fewer concerns, more time to relax and enjoy, and a welcome degree of 
security result. 
Waste disposal heads the list. A flexible drainpipe typically carries waste 
under the force of gravity to a point outside the vehicle for disposal. 
Additional sections of similar line are frequently required to extend the 
line to a more remote disposal site, when the standard pipe is not 
sufficiently long to extend the required distance. 
Connecting up the additional section of flexible drainpipe is awkward and 
time consuming, and thus requires extra effort however. The RV drainpipe 
connectors currently available have not been entirely satisfactory, and 
are greatly in need of improvement. 
Considering first the flexible drainpipe, formed from a coiled spring 
imbedded within a plastic casing, it offers both the strength and 
flexibility needed for typical camping use. 
A typical conventional coupler or connector is simply a short tube or 
hollow cylindrical member, designed to be forced into adjoining ends of 
two axially aligned drainpipe sections. Since the diameters of the pipes 
and the coupler are substantially the same, it often requires great skill 
and strength to force the coupler into the end of the pipe to seal them 
together. Intended to fit closely into the drainpipe ends, the connector 
must often be pried and pounded into place, perhaps in the rain, perhaps 
in darkness, but, even on a sunny day, with great difficulty and often 
with damage to the drainpipe resulting. At the very least, the end of the 
drainpipe must become deformed by manually applied force to enable it to 
receive the coupler. 
Consequently, it is desirable to have some better, easier to install 
device--one that can rapidly interconnect adjacent ends of two axially 
aligned flexible pipes in fluid communication, and be installed with 
little skill and attention. 
Once in place, such couplers often continue to require unwanted attention. 
They often form an inadequate mechanically strong joint, for example, 
leaking and easily dislodging if bumped by a squirrel, or accidentally by 
a campsite vitor. Stress on the joint caused by uneven terrain also 
produces this result. Thus, it is desirable to have a device that produces 
a better, stronger, tighter joint. 
Disassembly of the extended drainline has its problems as well. Drainpipe 
must be disassembled after an outing to enable cleaning and storage, and 
waste material remaining within the drainpipe makes it essential that this 
be done carefully to avoid strewing the waste about the campsite. 
Unfortunately, due to the tight friction fit, it is very difficult to 
forceably pull the coupler out of the end of the pipe, without spilling 
the waste contained within the pipe. 
Existing connectors often only compound the problems, by becoming 
accidentally dislodged at inopportune times with waste spilling therefrom. 
Consequently, it is desirable to have a device that functions more 
predictably in this respect to enable controlled disassembly, to avoid or 
at least greatly reduce the possibility of spilling waste material. 
There have been many different types and kinds of couplers and adapters 
designed for similar purposes. Refer, for example, to U.S. Pat. Nos. 
2,419,453; 2,441,055; 2,885,225; 3,667,787; 3,806,169 and 4,061,368. But 
none solve the foregoing problems. 
DISCLOSURE OF INVENTION 
Therefore, the principal object of the present invention is to provide a 
new and improved device for coupling in fluid communication a pair of 
axially aligned ends of flexible pipes, such as the type of drainpipe 
commonly employed on recreational vehicles. 
It is a further object to provide such a new and improved coupler that is 
easy and convenient to install, while providing a joint of adequate 
mechanical strength and tightness for sealing purposes. 
Yet another object of the present invention is to provide such a coupler 
that is easily and inexpensively manufactured, and can be readily and 
conveniently disassembled. 
Briefly, the above and further objects of the present invention are 
realized by providing a coupler that employs a tubular member for 
insertion between two sections of flexible drainpipe to be coupled. A 
first external thread on a first end portion of the tubular member 
threadably engages the internal helical corrugated surface of a first one 
of the two sections of pipe, along with a second external thread on a 
second end portion for threaded engagement of an internal helical 
corrugated surface of the second flexible pipe section. Thus, the coupler 
can be threaded into two adjoining ends, without the need for prying and 
pounding, and thus without the need for excessive manually applied force. 
An integrally formed annular flange in one form of the invention serves as 
a finger grip with which to thread manually the tubular member into the 
pipe. A cut-out portion on the flange prevents axial misalignment of the 
ends of the coupled sections, at the coupling, when placed upon the 
ground. 
Tapered end portions facilitate guiding the end of the coupler into the end 
of the flexible pipe. Also, the inventive coupler includes first and 
second pairs of axially aligned, spaced apart internal threads to receive 
threadable ends of a pair of the smaller diameter flexible pipes. The 
internal diameter flexible threads on the tubular member match the 
helically-corrugated plastic casing of the conventional flexible pipe. 
Thus, the coupler of this invention achieves the easy and convenient 
installation desired, while providing a highly superior joint that is 
tighter, stronger, and far less prone to inopportune dislodgement.

DETAILED DESCRIPTION 
Referring now to the drawings, and more particularly to FIG. 1 thereof, 
there is shown a flexible pipe coupler 10, which is constructed in 
accordance with the present invention, and which is shown in place within 
adjoining axially aligned, ends of flexible drainpipe 20 and flexible 
drainpipe 30 to interconnect them in fluid communication. Drainpipe 20 is 
connected to a recreational vehicle 40 at drain outlet 42 by conventional 
coupling device 44. Coupler 10 maintains pipe 20 in fluid communication 
with section 30, and thus waste flows from the vehicle 40 through flexible 
pipes 20 and 30, to disposal site inlet 50. 
Thus, the coupler 10 of this invention enables interconnection of two 
sections of conventional flexible drainpipe, to facilitate interconnection 
of the vehicle drain outlet 42 with a remotely located sewage disposal 
site. By interconnecting the pipes 20 and 30, end-to-end, a flow path is 
extended from the outlet 42 to the inlet 50 of the remotely located site. 
Referring now to FIG. 2, coupler 10 generally comprises a tubular member 11 
that is shaped and suitably dimensioned to fit threadably within the ends 
of two flexible pipes to be coupled. The coupler 10 is formed from a 
suitable thermoplastic material injection molded according to well known 
fabrication methods. 
As shown in FIGS. 2-4, tubular member 11 includes a first end portion 60 
extending to first distal end 62 for guiding the coupler into the end of a 
flexible pipe. The taper is slight, and thus is not apparent in the 
drawings. Exterior threads 64 and interior threads 66 are disposed at the 
front end at the respective outside and inside thereof. Tubular member 11 
also includes a second tapered end 70 extending to the distal end 72, and 
along which are disposed exterior threads 74 and interior threads 76. 
Generally, midway between these two end portions, is located outwardly 
extending annular flange 80. This flange has a cutback portion 82 along a 
portion of its periphery. Inwardly extending annular flange 84 is also 
generally midway between the two end portions. Like outwardly extending 
annular flange 80, inwardly extending annular flange 84 serves as a stop 
against which a section of drainpipe is screwed when screwed within the 
coupler. Thus, outwardly extending annular flange 80 serves as a stop 
against which illustrated drainpipe sections 20 and 30 are screwed. 
Outwardly extending annular flange 80 also serves as a grip that can be 
grasped with the fingers of the user to thread the coupler 10 into 
position. It extends radially outwardly a sufficient distance beyond the 
threads to serve this function. 
Cutback portion 82 serves to prevent misalignment of drainpipe section 20 
and drainpipe section 30 when placed upon a support surface. 
As shown in FIG. 2 and in the enlarged portion thereof in FIG. 3, the 
threads are shaped and dimensioned to mate with the helically-corrugated 
shape of the RV drainpipe. Drainpipe section 20, for example, is formed 
from a coiled hardened steel spring 22 imbedded within a sheet plastic 
casing 24. Similarly, drainpipe section 30 is formed from a coil of 
hardened steel 32 imbedded within plastic sheets 34 to produce a 
helically-corrugated casing. These helically-corrugated casings simulate a 
standard thread so that by providing the tubular member with a mating 
thread, the tubular member can be screwed into the drainpipe section to 
provide a superior coupling. 
Further details of cutback portion 82 of the outwardly extending flange 80 
are illustrated in FIG. 4. FIG. 4 is a cross section taken on line 4--4 of 
FIG. 2, with the drainpipe sections shown supported on support surface 52. 
Cutback section 82 extends from Point A on outwarding extending annular 
flange 80 to Point B along an arc designated reference numberal 83 in FIG. 
4 that is approximately 90 degrees. Thus, the outwardly extending annular 
flange 80 does not rest upon support surface 52 to elevate and misalign 
the drainpipe sections. Instead, cutback section 82 enables drainpipe 
sections 20 and 30 to rest directly upon the support surface in proper 
alignment without the slight hump that would otherwise affect flow along 
the drainline thus established. 
Turning now to FIG. 5, there is shown another form of a drainpipe coupler 
constructed in accordance with the invention. Reference numerals are 
increased by 100 over those designating similar components and FIGS. 1-4. 
In this alternate form, tubular member 110 is shaped and dimension 
relative to drainpipe section 120 so that it can be screwed on over the 
drainpipe section, interior threads 124 being shaped and dimension to mate 
with the helically-corrugated casing defined by spring 122 within plastic 
sheets 124. In this application inwardly extending annular flange 184 is 
called in service as a stop. Futhermore, both coupler 110 in FIG. 5 and 
coupler 10 of FIGS. 1-4 include both exterior threads and interior threads 
to enable use with two different sizes of drainpipe. 
In operation, the coupler is threaded into the end of one section of 
drainpipe, and then the other section of drainpipe is screwed onto the 
coupler. Additional sections are joined in this manner if needed and when 
an adequate length is achieved, one end is connected to the RV using a 
conventional coupler, and the other end is placed at the disposal site. 
When placing the line upon the ground, cutback portion 82 is directly 
downwardly to avoid producing a hump in the line of the coupling. 
Disassembly is equally convenient, the line may be first disconnected from 
the vehicle, transported by hand away from the RV for removal of the 
coupler and cleaning, and then brought back to the RV for storage. 
Thus, the flexible drainpipe coupler of this invention provides a 
significant improvement over prior art couplers. 
As various changes may be made in the form, construction, and arrangement 
of the procedures and parts described herein, without departing from the 
spirit and scope of the invention and without sacrificing any of its 
advantages, all matter herein is to be interpreted as illustrative and not 
in any limiting sense.