Abstract:
A coupler for a pipe or hose section has a coupling body, at least one coupling piece integrally formed therewith and a pressing sleeve, which can be previously joined to the coupling body. The coupling body and the pressing sleeve can be previously joined by a locking or interlocking connection.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a coupler for a pipe or hose section. 
     U.S. Pat. No. 4,407,532 discloses a coupler with a hose section having a coupling body with a coupling piece integrally formed therewith and a pressing sleeve which can be pre-assembled to the coupling body. When using this coupler, a connectable hose end is introduced in an annular gap between the coupling piece and the pressing sleeve and connected by concentrically pressing the pressing sleeve together with the coupler. 
     The desired pre-assembly between the coupling body and the pressing sleeve is achieved with known couplers by inserting the pressing sleeve with its front end over the area of the coupling body adjacent to the coupling piece and pressing a stop projection projecting inwardly from the pressing sleeve through a plastic deformation in an annular stop groove in the coupling body. Since the inside diameter of the stop projection of the pressing sleeve is larger than the outside diameter of the annular projection, in order to be able to insert the same over the annular projection formed between the stop groove and the coupling piece, prior to achieving the pre-assembly, substantial pressure must be applied to the plastic deformation to achieve the pre-assembly and a special tool is required for this. The rejection rate with couplers is relatively high in the production of such pre-assembly. The above-mentioned pre-assembly between the coupling body and the pressing sleeve is not suitable for the use of coupling bodies made of plastic since they would not withstand the pressures exerted upon them when producing the pre-assembly. The use of coupling bodies of plastic is, however, advantageous with regard to use for coupling for pipes or hoses carrying water. 
     SUMMARY OF THE INVENTION 
     The invention therefore relates to a generic coupling in which the coupling body and the pressing sleeve can be pre-assembled in a simple manner that is favorable in terms of production costs. 
     Through the use of a locking or interlocking connection, the pre-assembly of the coupling body and pressing sleeve can be achieved rapidly and simply without tools and without risk of damage. 
     When selecting a locking connection, it is preferable that the front end be designed in an elastically deformable manner with the pressing sleeve where the front end of the pressing sleeve preferably locks with the coupling body upon spring-back. 
     The inventive coupler is advantageously suited for the use of plastic, particularly polymers such as polysulfone or polyphenylene sulfone, as the material of the coupling body where the pressing sleeve can consist of stainless steel. 
     With such a coupler, pipe or hose sections can be connected with as many additional connections as desirable such as additional pipe or hose sections. Other arrangements such as Ts, reducers, elbows, transitions to sections with internal or external threads or similar types are possible with the inventive coupler. Further advantages and details of the invention are shown in the accompanying drawings. In the Figures: 
    
    
     BRIEF DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a top view of the inventive coupler, 
     FIG. 2 shows details of the coupling body of FIG. 1, 
     FIG. 3 shows a side view from the direction III in FIG. 2, 
     FIG. 4 shows a cross-section taken along line IV—IV in FIG. 2, 
     FIG. 5 shows a cross-section taken along line V—V in FIG. 3, and 
     FIG. 6 shows an enlargement of section VI in FIG.  5 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The coupler shown in FIGS. 1 and 5 has a coupling body  1  that has two coupling parts extending on either side. Each connecting part  2  receives a pressing sleeve  3  and each pressing sleeve  3  is bent inward at its front end opposite the free end of the connecting piece  2 , to form a stop projection  4  that extends into a stop groove  5  on the coupling body  1  almost completely circling it. 
     In the embodiment shown, each stop groove  5  is interrupted at two opposing locations by projections  6 . The pressing sleeves  3  have recesses, formed as openings  7 , corresponding to the projections  6 , into which the projections  6  extend, preventing rotation of the pressing sleeve  3  in relation to coupling body  1 . The inside radius of the pressing sleeve  3  and the outside radius of the projections  6  are so closely fitted to each other that the rotation prevention achieved gives way after a certain torsional force exerted on pressing sleeve  3  or coupling body  1  is exceeded, enabling rotation of the pressing sleeve  3  in a circumferential direction. This arrangement thus forms an additional overload protection and thus, for example, prevents shearing off from the coupler of a pipe or hose connected with the coupler. 
     Furthermore, the openings  7  in the pressing sleeve are longer in the axial direction of the coupler than the projections  6  and thus provide a window for the checking of the proper insertion depth of the pipe or hose sections to be coupled together. 
     Each stop groove  5  subdivides the area of coupling body  1  holding a pressing sleeve  3  into a ring shoulder  8  and a flange-like projection  9  projecting beyond the outside diameter of pressing sleeve  3 . The surface of projection  9  facing pressing sleeve  3  is flat and forms a guide or positioning stop for an implement. The coupling body  1  is reinforced in the middle between the two flange-like projections  9  by means of four ribs  10  arranged circumferentially at equal distances in the longitudinal direction of coupling body  1 . Each of the two coupling pieces  2  has three ribs  11  running radially that take over the sealing function so that a sealing ring and a channel for insertion therefor into coupling piece  2  become unnecessary. The outmost rib  11  has a conical portion  12  in the embodiment shown, which conical portion facilitates the insertion of a hose or pipe section in connection with an outwardly-expanded area  13  of the pressing sleeve  3 . 
     In the embodiment shown, the ring shoulder  8  holding the pressing sleeve  3  is formed with an oval cross section (FIG.  3 ). The largest diameter on the ring shoulder  8  is spaced 90° from the projections  6 . For the pre-assembly of the pressing sleeve  3  with the coupling body  1 , the pressing sleeve  3  can be temporarily deformed into an oval shape by pressure on the areas with the openings  7  and then inserting the pressing sleeve  3  over the ring shoulder  8 . Upon release, the pressing sleeve  3  returns to its original round form and locks with the annular stop projections  4  behind the ring shoulder  8  that project over the inside diameter of stop projections  4  so that a secure pre-assembly is achieved. 
     In place of the preferred embodiment of a locking coupling described above, any other locking or interlocking coupling can be used that insures a secure, lasting coupling without using tools and that does not require unreasonable design expenses. Thus, for example, a circumferential locking groove is conceivable in connection with a temporarily expandable locking band on the pressing sleeve or a bayonet-style interlocking of the parts.