METHOD FOR FIXING A CROSSBAR TO A BORDER PROP, PARTICULARLY IN A CABLE RACK, AND A JOINT THUS MADE AS WELL AS A BAR PROFILE FOR SAID JOINT

Abstract: A method, joint and profile bar for fixing a crossbar (3) to a border prop (2), particularly in a cable rack, according to which the crossbar is positioned with its end surface against a web plate (4) of the prop and is secured to the web plate by means of fixing elements (13) extending through said web plate. To avoid holes made in advance in the web plate, a counterpart (9) supporting the web plate in the region of the end surface of the crossbar, exclusive of the sites of the fixing elements of the crossbar, is positioned against the web plate, and the crossbar is pressed from the opposite side against the web plate so that a wall (8) of the crossbar is axially collapsed (8a) in the region supported by the counterpart, but cuts through the web plate in the regions unsupported by the counterpart and itself punches holes (12) for the fixing elements thereinto.

Description: Method for fixing a crossbar to a border prop, par¬ ticularly in a cable rack, and a joint thus made as well as a bar profile for said joint 5 This invention relates to a method for fixing a crossbar to a border prop, particularly in a cable rack., according to which method - the crossbar is positioned with its end surface against a web plate of the border prop, . 10 . - the crossbar is secured to the border prop by means of fixing elements extending from the end surface of the crossbar through the web plate of the border prop, and - a counterpart supporting the web plate in the 15 region of the.end surface of the crossbar is positioned at the fixing point of the crossbar, against the web plate of the border prop. To guide electric cables in groups from one location to another, so called cable racks are used 20. in factory halls, passageways and similar spaces, said cable racks being fixed to the ceiling or walls of ' ■' ■' • s id spaces and the cables being installed to rest on said cable racks. ■Cable racks are manufactured of separate parts 25 ' formed by metallic profile bars, i.e. of two border ■ props and a plurality of crossbars which are assembled into a ..supporting ladder of a U- or H-shaped cross- section. To provide a rigid, firm structure, the crossbars must be secured with their ends to the border 30' props either by welding or mechanically. Carrying out the fixing of the crossbars by welding, e.g. Finnish Patent No. 37 418, it is difficult to. produce neat, work, and welding will diminish the strength of the props and crossbars when said parts 5 are manufactured of extruded aluminium profile bars. Welding requires of the crossbar a certain thickness and is more difficult to automatize than fixing carried out mechanically. On the other hand, mechanical fixing requires 5 punching . * of some kind of- fixing tongues at the ends of the crossbars and punching respective cuts in the borde props and upsetting or twisting said tongues after .the tongues have been pushed through the cuts. The mechanical fixing method is thus both laborious 10- and slow and has generally been based on working the ends of the severed crossbar into fixing tongues. Finnish patent publication No, 68 305 suggests a method on account of which the crossbar can be ■ mechanically secured to the border prop without need 15 of working any fixing tongues at the.end of the cross¬ bar. Even though this method considerably simplifies the joining of the crossbar and prop, it still requires punching of cuts in the border prop and additionally a certain cross-sectional profile for the web plate of 20 the border prop at the junction point. The object of this invention is to provide a method avoiding the above stated disadvantages and permitting the joining of the.crossbar and prop simply and rapidly even at the installation site. This object 25 is achieved by the method of the invention, which is characterized in - that the web plate is supported in the region of the end surface of the crossbar, exclusive of the sites of the fixing elements of the crossbar, and ' 30 - that the end surface of the crossbar is pressed from the opposite side against the web plate of the border prop so that the wall of the crossbar is axially collapsed in the region supported by the counterpart, but cuts through the web plate of the border prop in 35. the regions unsupported by the counterpart, forming said fixing elements extending through the web plate. The invention is based on the idea that the crossbar itself is caused to punch into the border . prop the holes that are required for the crossbar simply by pressing the end of the crossbar against the border prop and similarly to . form at the end of the crossbar the.fixing ' elements that are -required for th crossbar. ■ When the crossbar is pressed against the web plate of the border prop and the plate is sup- ported from the opposite ' side with a suitable counter-. part, those parts of the end of the crossbar at which ■ ■ there are recesses, in the counterpart cut through' the web ' plate, whereas those parts of the end of the crossbar against which there is . a wall-supporting counterpart on the opposite side of the web plate of the border prop are collapsed against the web plate of the border prop without penetrating the plate. Thus the . fixing elements required by the joint are formed automatically by means of mere compressive force which . can be easily generated by simple compression means. The • locking • of . the peg-like fixing elements thus formed on the crossbar to the web plate of the border prop can also be effected in the same compres¬ sion ste wherein the fixing elements are formed. ' This. can be realized so that the crossbar is pressed against the border prop so far that the ends of the fixing elements of the crossbar are upset against the counterpart. The invention also relates to a joint made ' according to this method, comprising fixing elements extending fro the end surface of the crossbar through the web plate of the border prop and secured to the web plate on the opposite side thereof. Such a joint is characterized in that the fixing elements of the crossbar protrude through holes punched by the fixing elements themselves into the web plate and that the crossbar walls between the fixing elements are axially collapsed at least the thickness of the web plate. Such a joint can be simply, produced, as has 5 been stated in the above, and enables rigid attachment of the crossbar to the border prop. The joint.does not require any special profile -of the web plate of the border- prop, but ' a smooth surface at the junction point ' is sufficient. 1.0 ' The invention also relates to a bar profile for a hollow crossbar suitable for carrying out the method. Such a bar profile, is characterized in that the ' wall of the bar profile, has at least one axial continuous expansion forming a fixing element extending 15 through the we plate of the border prop in the ready joint, and that the wall elements associated with the expansion are so thin that they can be axially collapsed to ' be located with their end surfaces in a plane different from that of the end surface of the expansion. 20 Such a bar profile has the advantage that the crossbar can be cut from a bar profile into a piece of desired length whose end surfaces need not be worked in any way after right-angled- cutting. Thus, subsequent to cutting the crossbar is ready as such to be disposed 25 with its.planar end surface against the planar surface of the border prop and to be secured to the prop. The following is a more detailed description of the invention with reference to the accompanying drawings, wherein 30 Figure 1 is a perspective view of a cable rack wherein the fixing method of the invention has been imp1emented, Figure 2 shows in a larger size a crossbar and a border prop as well as a counterpart for a cable 35 rack, detached from one another prior to the fixing of the crossbar. Figures 3, 4 and 5 are side projections of the steps of producing a joint between the crossbar and prop at the beginning, intermediate step, and end of the - fixing respectively. Figure 6 shows a ready joint seen in the direc¬ tion of the prop, and Figures 7 and- 8 are perspective views of. a ' crossbar .cut from a profile bar prior to the manufactur- ing of the joint and thereafter, respectively. The cable rack 1 shown in the drawings is ladder¬ like and has a U-shaped cross-section, comprising two spaced-apart parallel border- props 2 interconnected with a.,plurality of crossbars 3 spaced apart in the : longitudinal direction of the props. The border props and crossbars have been cut into pieces of a suitable length from metal, preferably aluminum, profile bars. The border prop 2 forms a planar web plate 4 and lengthwise reinforcement flanges 5 pertaining thereto. The. crossbar 3 is constituted by a hollow piece of a substantially right-angled cross-section,, and the crossbar has planar end surfaces 6 located perpen¬ dicularly to the longitudinal axis of the crossbar. Each corner of the crossbar, has a lengthwise expansion 7 of a circular cross-section, and the expansions are connected relatively thin, walls 8. To fix the border prop and crossbar to one another, the crossbar is disposed with its end surface 6 against the web plate 4 of the prop. On the opposite side of the fixing point, a counterpart 9 is positioned against the web plate, the end surface 10 of said counterpart corresponding to at least the end surface of the crossbar exclusive of the regions corresponding to the expansions of the crossbar, at which regions the end surface of the counterpart has cylindrical recesses 11. The recess 11 has a diameter slightly greater than the diameter of the expansion 7 of the crossbar. The counterpart has been secured to a compression tool having gripping means which can be adjusted to grip the crossbar in an axially non-slidable manner and which can be forced toward the counterpart. The tool has-.been shown only, schematically iri Figure- 2 by dotted lines. When the crossbar is pressed by means of the tool against the web plate of the border prop simul¬ taneously as the counterpart is- tightly pressed from the opposite side against, the web plate, the expansions 7 of the crossbar cut through the web plate, whereas the wall' sections 8 of the crossbar are axially col¬ lapsed, 8a, the counterpart serving as an anvil on the Opposite side of the web plate. The expansions of the crossbar thus punch round holes 12 into the web plate and form cylindrical fixing pegs 13 extending throug the web plate. When the pressing of the crossbar against the web plate .is still, slightly continued, the ends of the fixing pegs are pressed, by means of the punch- severed piece of plate 14, against the bottoms of the recesses 11 in the counterpart,' so ' that the ends of the. pegs are upset and secure the fixing pegs to the web plate. The counterpart may be provided with suitable means reliably pushing the punch-severed piece of plate out from the recess after the removal of the counterpart. It is noted that no cuts or the like need be made in the border prop in advance, but the web plate may have a smooth fixing surface, and that no protru¬ sions or the like need be made at the end of the crossbar, but ' a straight-cut planar end surface is sufficient. The fixing method is very rapid, and the necessary compression means is of a simple construction. The drawing and the description pertaining thereto are intended merely to illustrate the idea of the invention. Even though the invention has been explained in the foregoing mainly in connection with a cable rack, it is evident that the fixing method according to the invention is suitable for application to the production of other objects as well, said-objects • involving securing a bar to a plate-like element. The' expansions forming the fixing elements may vary in their for and location considerably, depending on the joint involved in each case. The invention can thus vary within .the scope of the claims.

Claims: AMENDED CLAIMS [received by the International Bureau on 29 March 1989 (29.03.89); original claim 1 amended; other claims unchanged (1 page)] 1. A method for fixing a crossbar (3) to a border prop (2) , particularly in a cable rack (1) , according 5 to which method - the crossbar (3) is positioned with its end sur¬ face (6) against -a web plate (.4) of the border prop (2) , - the crossbar is secured to the border prop by mean ' s of fixing elements ' (13) extending from the end 10 surface of the crossbar through the wab plate of the border prop, - a. counterpart (9-) supporting the web plate in the region pf he' end surface (6) of the crossbar is positioned at the fixing point of the crossbar ' (3) , 15. ' against the web plate (4) of the border prop (2)., and - the web plate (4) is supported by a counter¬ part (9) in the region of the end surface of the cross¬ bar, c h a r a c t e r i z e d in - that the web plate (4) is supported by the 20 counterpart (9.) in the end surface region exclusive of the sites of the fixing elements (13) of the crossbar, and - that the planar end surface (6) of the cross¬ bar is pressed from- the opposite side against the web 25 plate (4) of the border prop so that a wall (8) of the crossbar is axially collapsed (8a) in the region sup¬ ported by the counterpart, but cuts through the web plate of the border prop in the regions unsupported by the counterpart, forming said fixing elements (13) ex- 30 tending through the web plate. 2. A method as claimed in claim ____. , c a r ¬ a c t e r i z e d in that the crossbar (3) is pressed against the border prop (2) so far that the ends of the fixing elements (13) of the crossbar are upset against 35 the counterpart (9) . 3. A method as claimed in claim 1 or 2,

Inventors: HOTANEN MARTTI, HOTANEN, MARTTI
Applicants: NOKIA OY AB, OY NOKIA AB
Application year: 1988
Main classification: F16B11
IPC codes: F16B5, F16B17, H02G3