Pipe coupling means for connecting two pipe ends to each other

A pipe coupling for coupling pipe ends to each other, one pipe end having at its end an annular shoulder limiting the sliding of a first sleeve member over the pipe end. The second sleeve member is so dimensioned that it fits over a piping end and is welded to same. The two sleeve members are insertable into each other such that a clamping shell comprised of two half-shells hinged to each other engages exterior shoulders of the sleeve members at a location wherein the two sleeve members are overlapped one by the other. Preferably, the second sleeve member is integral with a flange for connecting the member to an existing sleeve on the respective piping end. The invention results in a short overall structure facilitating the use of the coupling with flanged pipe connections of a piping system.

BACKGROUND OF THE INVENTION 
The invention relates to pipe couplings for connecting two pipe ends of 
which one has an annular protrusion, provided with an annular seal 
directed radially outwardly. The coupling includes a sliding sleeve, 
overlapping the annular protrusion and is movable in axial direction 
relative to the said pipe end. The counterpart of the sliding sleeve end 
connectable with same is a sleeve section secured, e.g. by welding, to the 
other or second pipe end. The sliding sleeve and the sleeve section have 
each a radially outwardly protruding annular protrusion or shoulder 
engageable by a clamping shell usually comprised of two half-shells hinged 
to one another and held in closed state by a clamping lever mechanism. 
It is known in the couplings of this type to provide the equivalent of the 
sleeve section such that it is in fact an insert which can be inserted 
into a first sleeve part forming functional counterpart of the said 
sliding sleeve. If the end of the piping to be attached to the sleeve 
section has a connecting flange at its end, then a complementary flange 
must also be welded to the outside of the insert. This results in 
relatively large overall length which often hinders or makes the use of 
such a pipe coupling impossible. 
SUMMARY OF THE INVENTION 
It is, therefore, an object of the present invention to provide a coupling 
device suitable for connecting pipe ends and having a shorter overall 
length and, if necessary, connectable to an existing flange of the piping. 
In general terms, the present invention relates to a pipe coupling means 
for connectiing two pipe ends to each other, a first one of said pipe ends 
having an annular protrusion having an annular seal disposed in the 
radially extending surface of the protrusion, said coupling means being 
provided with a sliding sleeve adapted to overlap said annular protrusion 
and to be movable in axial direction relative to said first pipe end; with 
a sleeve section adapted to be fixedly secured to the second one of said 
pipe ends and to be releasably secured to said sliding sleeve, said 
sliding sleeve and said sleeve section having an annular clamping 
protrusion and a radially outwardly protruding flange, respectively, and 
outer shell means adapted to overlap the annular clamping protrusion and 
the radially outwardly protruding flange when the coupling means is 
closed, said outer shell means comprising two half-shells hinged to one 
another, and adpated to be closed by a clamp lever closure, an improvement 
wherein the sleeve section is adapted to surround a part of the sliding 
sleeve, said sleeve section having inside diameter of the size allowing 
the second pipe end, whose inside diameter generally corresponds to that 
of said first pipe end, to be inserted into said sleeve section, the 
annular clamping protrusion of said sleeve section is disposed on the 
exterior thereof, and the sliding sleeve has an outer annular seal 
interacting with the interior of said sleeve section. 
As a result the overall length of the device is considerably shortened in 
the area of the insert. The outer shoulder of the insert can be arranged 
over the area in which the insert and the sliding sleeve overlap each 
other. If necessary, the sleeve section can be provided with a connecting 
flange which is also located at least partially over the actual area of 
overlapping, so that the part of the device forming the sleeve section 
requires only a very short additional overall length to extend over the 
end overlapped by the counterpart of the coupling. 
The pipe end piece, insertable into the sleeve section, can be a part of an 
existing piping and need not even have especially machined seal engaging 
surface. The sleeve section need only be slid onto such pipe end piece and 
welded to it. 
However, according to the invention, the sleeve section can also be 
provided with a connecting flange, whereby a pipe end piece can be 
inserted into the sleeve section to form, with the inner wall of the 
sleeve section, an annular space containing the sliding sleeve of the 
other pipe end. Thus, the pipe piece can be clamped in the sleeve part or 
be connected with the sleeve part by shrinking or welding. The sleeve 
section then has an essentially smooth outer end so that a piping end part 
provided with a connecting flange can be fastened to this end by bolts 
connecting the flanges. In each case, the pipe piece inserted or 
projecting into the sleeve part guarantees a constant inner flow 
cross-section. 
It is further advantageous according to the invention if the inner diameter 
of the sliding sleeve expands slightly conically towards the front end of 
the sliding sleeve. In this manner, it is attained that the annular seal, 
provided at the annular protrusion of the pipe end attached to the sliding 
sleeve engages the sliding sleeve, and becomes flush with its inner wall 
only when the sliding sleeve is fully inserted into the sleeve part 
attached to the other pipe end. By means of the axial mobility of the 
sliding sleeve on the pipe end, it is, moreover, guaranteed that the 
connecting and disconnecting of the coupling can be effected without 
requiring axial displacement of the respective piping ends relative to 
each other. 
If the sleeve section is provided with a connecting flange, the clamping 
half-shells can be secured to the connecting flange by means of a hinge 
bolt to prevent their loss on disconnecting the coupling.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
A first pipe end 10 has an outer annular protrusion 11 into which an 
elastic annular seal 12 is inserted. On the pipe end 10, a sliding sleeve 
13, which also has an annular seal 14 in its outer peripheral area, is 
arranged for movement in axial direction relative to the pipe end 10. In 
addition, the sliding sleeve 13 has an outer annular protrusion 15 and 
handles 16 which facilitate the shifting of the sliding sleeve 13. 
The counterpart is formed as sleeve section 17 whose end facing the sliding 
sleeve 13 has an inner cross-section adapted for a sliding engagement over 
the adjacent section of the sliding sleeve 13. When the sleeve section 17 
is pushed onto the sliding sleeve 13, the annular seal 14 engages the 
inner surface of the sleeve section 17. A radially outwardly protruding 
flange 18 of the sleeve section 17 is provided over the insertion area. 
A pipe piece 19 is inserted into the sleeve section 17. The inner diameter 
of the pipe piece 19 is flush with that of the pipe end 10, whereas the 
outer diameter of the pipe piece 19 corresponds to the inner diameter of 
the sliding sleeve 13 at a sliding clearance between the two. The pipe 
piece 19 is secured to the sleeve section 17 by a welding seam 20. The 
sleeve section further comprises an annular connecting flange 21 which is 
provided with bores 22. Consequently, the end of a piping not illustrated 
in the drawings which is also provided with a complementary connecting 
flange can be connected with the flange 21 by bolts or the like, also 
becoming fixedly secured to the sleeve section 17. 
It is, however, also conceivable that the pipe piece 19 may itself be an 
end section of an existing piping, to which the sleeve section 17 is 
welded at 20. 
The sliding sleeve 13 has an inwardly projecting annular shoulder 23, which 
is adapted to abut axially against the annular protrusion 11 of the pipe 
end 10, so that the latter cannot be pulled out of the sliding sleeve 13. 
The inside diameter of part of the inner wall of the sliding sleeve 13, 
disposed forwardly of the shoulder 23 (to the left of FIG. 1) and 
designated with reference numeral 24, expands slightly conically towards 
the front of said sliding sleeve. When the sliding sleeve 13 of FIG. 1 is 
pushed onto the pipe end 10 towards the right in order to release the 
connection, the annular seal 12 is correspondingly released in radial 
direction, so that it is no longer in frictional engagement with the inner 
wall of the sliding sleeve 13 and an easier shifting is possible. 
Two half-shells 25, each provided with an inwardly projecting flange 26 at 
each end thereof, serve to hold the sliding sleeve 13 and the sleeve 
section 17 together. The half-shells 25 are connected to each other by a 
hinge bolt 27 at one side. The other side of the half-shells 25 can be 
connected by a clamp lever closure, which consists of a spring 28 and a 
clamp lever 29 and is fastened to one of the half-shells 25 by a bolt 30. 
In order to close the coupling, the curved end of the spring 28 is hooked 
behind a protrusion 31, at the other half-shell 25. As shown in FIG. 1, 
the half-shells 25 overlap the sleeve section 17 and the sliding sleeve 13 
in such a way that the respective flange 26 are disposed each axially 
outwardly of the annular protrusion 15 and the flange 18, respectively. 
The hinge bolt 27 or an additional hinge bolt passing through the lower 
opening below the bolt 27 in FIG. 2 (only the opening being shown in the 
drawing) can also be used for securing the outer shell means formed by the 
two half-shells to the flange 21. 
Those skilled in the art will appreciate that further embodiments exist 
departing from the preferred embodiments described above, without 
departing from the present invention as defined in the accompanying 
claims.