Device for fastening together the parts of a heat-insulated composite section
BACKGROUND OF THE INVENTION 
     The present invention relates to a device for fastening together the parts of a heat-insulated composite section consisting of two metal sections and of at least one insulating rod, in which the insulating rod engages grooves in the metal sections, exterior groove webs can be shaped and forced against the insulating rod by one or more knurling rollers in the device, and each knurling roller is disk-shaped and secured in a mechanism that is fastened on and can be released from a shaft. 
     The mechanism in the known device of this type consists of two annular disks that rest against the lateral surfaces of the knurling roller and are fastened and forced together by screws that extend through passages bored through the knurling roller. The rigid mounting of the knurling roller leads to considerable problems in practice because the knurling roller must be aligned precisely in the center of the groove webs that are to be shaped in order to perfectly fasten the metal sections to the insulating rod or rods in the vicinity of the joint and the webs must not differ in thickness. 
     The knurling rollers, however, cannot be precisely aligned with the metal-section groove webs that are to be shaped when the tolerances of the parts to be fastened together are undesirably superimposed. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide a device of the aforesaid type that will result in a perfect joint between the separate parts even when their tolerances are superimposed undesirably. 
     This object is attained in accordance with the invention in that the knurling roller is mounted in the mechanism in such a way that it can be axially displaced. 
     The knurling roller can be axially displaced 0.5 to 1 mm to each side out of an intermediate position. 
     In one embodiment of the invention the knurling roller has two separated, conical, toothed, circumferential surfaces, with the bottom land between each pair of teeth paralleling the conical circumferential surface. This improves the transmission of forces from the knurling roller to the groove webs. 
     The axial displacement of the knurling roller makes it float over the outer metal-section groove webs, which it shapes, forces against the insulating rod, and knurls. The axial flotation makes it possible to compensate for errors in alignment resulting from relative motion between the composite section, which is generally manufactured in 6-meter lengths, and the knurling roller. 
     In another embodiment of the device in accordance with the invention, the knurling roller is mounted in such a way that it can be displaced axially on a bushing that is held between annular disks and the disks are forced together by screws that extend through passages bored through the knurling roller. 
     In a further embodiment of the device in accordance with the invention the bushing is in one piece with an annular disk. 
     In still another embodiment of the device in accordance with the invention the conical circumferential surface of the knurling roller is at an angle α of 50° to 60° to the horizontal. 
     The known embodiment and the preferred embodiments in accordance with the invention will now be described with reference to the attached drawings, wherein 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevation of a known device, 
     FIG. 1a is a view of the central standard along the direction indicated by arrow Ia, 
     FIG. 1b is a view of the central standard along the direction indicated by arrow Ib, 
     FIG. 2 is an elevation of the known knurling roller and its tensioning mechanism, 
     FIG. 3 is a view along the direction indicated by arrow III in FIG. 2, FIG. 4 is an elevation of a composite section subsequent to machining by the knurling roller illustrated in FIGS. 2 and 3, 
     FIG. 5 is a view along the direction indicated by arrow V in FIG. 4, 
     FIG. 6 is a partial vertical section of the knurling roller and mechanism in accordance with the invention as mounted on a powered shaft, 
     FIG. 7 shows the knurling roller illustrated in FIG. 6 while the joint is being produced, 
     FIG. 7a is a diagram of forces, 
     FIG. 8 is a view along the direction indicated by arrow VIII in FIG. 7, and 
     FIG. 9 illustrates a composite section with two insulating rods and two knurling rollers that operate in conjunction with the outer groove webs on the metal sections. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The known device for fastening together the parts of a heat-insulated composite section illustrated in FIGS. 1a and 1b has a central standard 1 that accommodates shafts that rotate around horizontal axes. The standard 1 as illustrated, has six shafts with rollers at the ends. Lower shafts 2, 3, and 4 cannot be adjusted in height. Shafts 2 and 3 have guide rollers, and shaft 4, which is powered, has a knurling roller. Upper shafts 5, 6, and 7 can be adjusted in height by a handwheel 8. Shafts 5 and 7, have guide rollers, and shaft 6, the shaft in the middle, is powered and has a knurling roller. 
     The device also has two slides 9 and 10 equipped with guide rollers 11 and 12, which are mounted in such a way that they can rotate around vertical axes and which can be displaced horizontally by means of handwheels 13 and 14. 
     It will be evident from FIGS. 1, 1a and 1b that two composite sections 15 can be finished simultaneously. The sections travel through the device in the direction indicated by arrow X. They are advanced by the knurling rollers, which are powered, and only guided by the other rollers, which are applied to the parts of the composite profile. 
     Standard 1 also accommodates, in addition to shafts 2 through 7, guide rollers 16, which rotate around vertical axes and only one of which is illustrated, in FIG. 9. 
     The known knurling roller 17 mounted on shafts 4 and 6 and illustrated in FIGS. 2 and 3, has two separated, conical, toothed, circumferential surfaces 18 and 19. As will be evident from FIG. 2, since the bottom land 20 between each pair of teeth parallels the axis 21 of rotation of knurling roller 17, the teeth are triangular in section. This results, as illustrated in FIG. 5, in a wide knurled strip in the groove webs 22 and 23 in metal sections 24 and 25 that are shaped by knurling roller 17. The width b of the knurled strip equals the width of bottom land 20. 
     The disk-shaped knurling roller 17 in the known embodiment illustrated in FIGS. 2 and 3 is held between two annular disks 26 and 27 that rest against the lateral surfaces of the roller, where they are secured by screws that pass through passages 30 bored through the roller and that are indicated by the dot-and-dashed lines 28 and 29 in FIG. 2. 
     The disk-shaped knurling roller 31 in accordance with the invention that is illustrated in FIG. 6 is mounted in such a way that it can be displaced axially on a bushing 32 that is held between annular disks 33 and 34. The holding elements are screws 35 only one which is shown in FIG. 6. The shaft of each screw extends through a passage bored through knurling roller 31, its threaded end 37 is screwed into a threaded hole bored through annular disks 33 and 34, and its head 38 rests on an annular area of annular disk 34. 
     Annular disks 33 and 34 are attached by means of a key 39 to the end 40 of powered shaft 6 in such a way that they cannot rotate in relation to the shaft. Annular disk 33 rests against an abutting surface 41 on shaft 6 and annular disk 34 is secured by a terminal disk 42 that is fastened by a screw 43 to the end 40 of the shaft. 
     In one variation of the design illustrated in FIG. 6, bushing 32 can be in one piece and have an annular disk. 
     Knurling roller 31, which is mounted in such a way that it can slide along bushing 32 parallel to axis 44 of rotation, has two separated., conical, toothed, circumferential surfaces 45 and 46. The bottom land 45a between each pair of these teeth parallels the conical circumferential surface of roller 31, which is at an angle α of 50° to 60° to the horizontal. 
     The force F exerted by knurling roller 31 on the groove webs 22 and 23 that are to be shaped (FIG. 7) can be broken down, as illustrated in FIG. 7a, into the components FR and FW, which powerfully force groove webs 22 and 23 against insulating rod 47. When groove webs 22 and 23 have, as in the illustrated embodiment, a projection that extends toward insulating rod 47 and the rod has a recess that accommodates the projection, the projections will mold perfectly into the associated recess as the result of the force components illustrated in FIG. 7a. 
     The angle α of incidence of the conical circumferential surfaces 45 and 46 of knurling roller 31 ensures that groove webs 22 and 23 will have only a very narrow strip of knurling as illustrated in FIG. 8. 
     In one variation of the embodiment described, the composite profile can be kept stationary and the device, equipped with at least one knurling roller 17, advanced over it. 
     FIG. 9 illustrates a composite section with two insulating rods and two knurling rollers that operate in conjunction with the outer groove webs on the metal sections. 
     It will be appreciated that the instant specification and drawings are set forth by way of illustration and not limitation, and that various modifications and changes may be made without departing from the spirit and scope of the present invention.