Abstract:
A process for securing a guiding member on a support which includes at least one opening which is substantially greater in dimension than an end of the guiding member which is supported therein. A space provided between the at least one opening and the end of the guiding member is filled with a polymerizable resin which is polymerized to secure the guide member within the opening after the guiding member has been precisely positioned in a predetermined position. A marking apparatus incorporates the guiding member secured to the support, and elements are provided for retaining the guiding member in position within the at least one opening and, in some embodiments, for selectively adjusting or removing the guide bar from the at least one opening.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a process for fixing a guiding member on a support. 
     2. Brief Description of the Related Art 
     It is necessary to position each guiding member with respect to the bearing surfaces which receive it, in extremely meticulous manner. To that end, it is known to machine said bearing surfaces to precise dimensions with respect to a reference surface of the support, so as to produce openings in which the guiding members are introduced with reduced clearance. 
     However, such a process has certain drawbacks. In effect, it involves an extremely meticulous machining, which leads to long manufacturing time and high costs. 
     Moreover, in the case of apparatus with low mechanical strength, such as marking apparatus, the quality of geometry hoped for is not always obtained once the assembly is effected. In effect, the marking apparatus is capable of being deformed under the effect of the stresses exerted by the flanging occurring during the corresponding machining, or under the influence of the cutting efforts of the tools used for such machining. 
     In order to overcome the drawbacks of the prior art set forth hereinabove, the invention has for its object a process for fixing a guiding member on a support which ensures a precise positioning of these different elements with respect to one another, while generating limited mechanical efforts. 
     SUMMARY OF THE INVENTION 
     To that end, the invention relates to a process for fixing a guiding member on a support, in which at least one opening adapted to receive an end of the guiding member, is made in the support, and this end is introduced in the opening. The opening is made with transverse dimensions substantially greater than those of the end which is received therein. The guiding member is placed in the precise position that it must occupy, an intermediary space is thus defined between the outer periphery of the end and the opposite walls of the opening, which intermediary space is filled with a polymerizable resin and said resin is polymerized so as to secure the end with respect to the opening. 
     The process according to the invention enables the objects set forth above to be attained. 
     In effect, being given that each opening is made with transverse dimensions clearly greater than those of the end of the guiding member which is received therein, the corresponding machining requires no particular precision. It may therefore be effected much more rapidly than that employed in the prior art processes, and does not involve flanging of the different elements. 
     The phase of relative positioning of the guiding member and of the opening in which the latter is inserted, may be carried out by simple mechanical means, for example a system of wedging. This therefore does not induce considerable efforts that may alter the geometry of the apparatus once produced. 
     Finally, the polymerizable resin introduced within the intermediary space made between the guiding member and the opening which receives it, ensures a reliable fixation of each guiding member on the support. 
     The invention also relates to a guiding device obtained according to the above process, comprising at least one guiding member fixed on a support, each end of this member being housed in a corresponding opening made in the support. The opening has transverse dimensions substantially greater than those of the end of the guiding member, and a liner is formed by a polymerizable resin in the solid state being cast in situ between the outer periphery of this end and the opposite walls of the opening. 
     The guiding device may comprises one or more of the following characteristics: 
     the guiding member may slide axially with respect to the liner and, in the vicinity of each end of the guiding member, there are provided removable means for axially immobilizing this end with respect to the support; 
     the removable immobilizing means comprise at least one fixing element screwed in a wall of the support in the vicinity of the opening, a part of said element projecting at the opening so as to retain the end of the guiding member in abutment; 
     the end of the guiding member comprises a shoulder, the removable immobilization means comprising a pocket of resin, disposed in the vicinity of the shoulder; 
     the outer periphery of the ends of the guiding member is surrounded by means of a possibly bevelled ring; 
     an anti-adhesive coating is disposed on the outer periphery of the ends of the guiding member; and 
     the ends of the guiding member are connected by a median part of smaller section. 
     Finally, the invention relates to a marking apparatus comprising at least one guiding device as described hereinabove. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be more readily understood on reading the following description given by way of non-limiting example, with reference to the accompanying drawings, in which: 
     FIG. 1 is a schematic view in perspective of a marking apparatus according to the invention. 
     FIG. 2 is a schematic view in section illustrating the phase of positioning a guiding member of the marking apparatus of FIG.  1 . 
     FIGS. 3 and 4 are schematic views in section illustrating a first variant embodiment, in two phases of assembly of a guiding member. 
     FIGS. 5 to  7  are views similar to FIGS. 3 and 4, illustrating a second variant embodiment of the invention, in three phases of assembly of a guiding member. 
     FIGS. 8 and 9 are views similar to FIGS. 3 to  7 , illustrating two additional variant embodiments of the invention. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring now to the drawings, the marking apparatus shown in FIG. 1 is generally designated by reference  2  and comprises, in manner known per se, a fixed frame  4  comprising two opposite flanges  6  supporting two bars  8  constituting guiding members, with a view to displacing a first carriage  10  along the axis of these bars. Said carriage is also provided with two guiding bars  12 , the two pairs of bars  8 ,  12  being disposed substantially at right angles. 
     Bars  12  ensure guiding of a second carriage  14  on which a marking head (not shown) is intended to be mounted. The two carriages  10 ,  14  therefore constitute the drive mechanism of the marking apparatus, and ensure the positioning of the marking head in two directions orthogonal to each other. The respective drive of the two carriages  10 ,  14  is ensured, in manner known per se, via electric motors (not shown). 
     The fixing of each bar on its respective support will be described hereinafter with reference to FIGS. 2 to  9 , in which reference will solely be made to the fixation of the bars  8  on the flanges  6  of the frame  4 . Fixation of bars  12  on the first carriage  10  is, of course, similar. 
     As shown in FIG. 2, each bar  8  comprises a cylindrical median part  8 A terminating in two cylindrical ends  8 B of larger diameter, of which only one has been shown. Bar  8  is intended to be fixed on the flange  6  by its ends  8 B. Each of the latter is received at a cylindrical through opening  16  made in the flange  6 . This opening  16  has a transverse dimension, namely a diameter D, which is substantially greater than that of the end  8 B, namely its diameter d. 
     With a view to fixing the bar  8  on the flange  6 , each end  8 B should firstly be introduced inside the opening  16 , then positioned relatively in accordance with the conformation that the marking device once produced must present. To that end, the bar  8  is maintained with respect to a reference surface of the frame  4 , in the present case a previously precision-ground base  6 A, at appropriate distances and configurations. Such maintenance may be ensured, for example, by a system of wedges. It should be noted that, in the example shown, the bar  8  and the opening  16  are not strictly coaxial. 
     Being given that the respective diameters of the end  8 B of the bar  8  and of the opening  16  are substantially different, the outer periphery of the end  8 B defines, with the opposite walls of the opening  16 , an approximately annular intermediary space  20 . While maintaining the bar  8  and the flange  6  in their relative positions set forth above, this intermediary space  20  is then filled by means of a polymerizable resin, for example an epoxy or polyurethane resin. It may also be provided to use other types of equivalent hardenable materials. 
     This resin is then polymerized in manner known per se. Once this polymerization is finished, the solidified resin filling the intermediary space  20  forms a liner within which the end  8 B of the bar is held. Consequently, the bar  8  and the flange  6  are perfectly secured with respect to each other, in accordance with the dimensions and orientations corresponding to the shown arrangement of the marking device. It is then possible to remove the wedging system having contributed to the relative hold of the bar and the carriage during the resin polymerizing time. 
     FIGS. 3 and 4 illustrate a first variant embodiment of the invention. The bar  8  which is mounted in two openings  16 ,  16 ′ made in the flanges  6 ,  6 ′ opposite the frame  4 , is similar to the one shown in FIG.  2 . However, the outer periphery of the ends  8 B of this bar  8  is coated with an anti-adhesive varnish which allows them to slide freely in the liners  21 ,  21 ′ of resin filling the intermediary spaces designated by reference  20  in FIG.  2 . 
     Two screws  22 ,  22 ′ are engaged in each flange  6 ,  6 ′. Their head  24 ,  24 ′ is disposed against the outer face  26 ,  26 ′ of each flange  6 ,  6 ′ and extends in the vicinity of each opening  16 ,  16 ′, with the result that each end  8 B,  8 B′ of the bar  8  abuts against the head of these screws. The bar  8  is therefore immobilized transversely, at its ends  8 B,  8 B′, via the liners  21 ,  21 ′ of resin. Moreover, this bar  8  is immobilized axially in two opposite directions, thanks to the head  24 ,  24 ′ of the screws  22 ,  22 ′. 
     Should it prove necessary to change the bar  8 , for example with a view to repairing it, one of the screws which immobilizes it axially, in the present case screw  22 ′ in the example shown in FIG. 4, should be removed. Thanks to the presence of the anti-adhesive varnish, the end  8 B′ is free to slide axially within the liner  21 ′, in the same way as the opposite end  8 B. Being given that the median part  8 A of the bar  8  is of smaller section than the ends, it is superfluous to coat it with such an anti-adhesive varnish for the purpose of ensuring its passage through the liner  21 ′. It should be noted that, during this dismounting operation, the second screw  22  remains engaged in the flange  6 . 
     It is particularly easy to assemble a new bar on its support. The ends thereof should firstly be coated with the anti-adhesive varnish. One of the ends of this bar is then introduced within the liner  21 ′ of which access is not prevented by the presence of a screw. This first end is then made to slide in this liner  21 ′. The median part is then passed, then the second end of this bar is slid therein. The latter is then positioned precisely in an axial direction, due to the presence of the screw  22  against which the first end of this new bar abuts. Moreover, this latter is perfectly positioned in a transverse direction, due to the presence of the liners of resin  21 ,  21 ′ having served to immobilize the first bar  8 . Securing of the new bar in translation is effected by replacing the screw  22 ′, removed for the purpose of dismounting the first bar  8 , in its original site. 
     Thanks to this embodiment, it is not necessary either to destroy the sealing resin or to use the particular tool having served to position and secure the first bar  8 . 
     FIGS. 5 to  7  illustrate a second variant embodiment of the invention. According to this variant, the bar  108  differs from that,  8 , shown in FIGS. 2 to  4 , in that each of its ends  108 B,  108 B′ is provided with a distal bevel or shoulder  110 ,  110 ′, with the result that they widen towards the median part  108 A. The liners of resin, inserted between the walls of the openings  16 ,  16 ′ and the outer periphery of the ends  108 B,  108 B′ of the bar, with a view to securing the latter with respect to the carriage  6 , are therefore no longer overall annular as was the case hereinbefore. These liners  121 ,  121 ′ comprise an annular part  122 ,  122 ′ extending in the vicinity of the cylindrical walls of each opening  16 ,  16 ′, as well as a pocket  123 ,  123 ′ located in the vicinity of each bevel  110 ,  110 ′. Although the ends  108 B,  108 B′ of the bar  108  are coated with an anti-adhesive varnish, this bar is perfectly immobilized both transversely, thanks to the annular parts  122 ,  122 ′ of the liners of resin, and axially, since these ends come into abutment against the pockets  123 ,  123 ′ which hinder the displacement of the bar. 
     If it is desired to dismantle this bar  108 , for example with a view to repairing it, it is necessary to break one of the pockets of resin, in the present case pocket  123  as shown in FIG.  6 . The corresponding end  108 B of the bar  108  is then free to slide axially within the annular part  122  of the liner  121 , due to the presence of the anti-adhesive varnish. The median part  108 A of smaller section is then passed through this annular part  122 , then the second end  108 B′ is finally slid therein. 
     The operation consisting in mounting a new bar on the flange  6  is effected in similar manner, by introducing this new bar from the opening  16  which is free of a pocket of resin  123 . The end of this new bar, previously introduced through this opening  16 , then comes into abutment against the non-destroyed pocket  123 ′, as shown in FIG.  7 . 
     Thanks to the invention, the positioning imparted to this new bar is given the same degree of precision as that of the first bar  108 . In effect, each end of the new bar is positioned in a transverse direction, thanks to the presence of the annular parts  122 ,  122 ′ within which the ends are introduced. Moreover, the axial positioning of the whole of the new bar is ensured by the pocket  123 ′ which was not destroyed during dismounting of the first bar, against which pocket the new bar abuts. 
     This new bar is secured in translation by casting a new pocket of resin in the site  124  of the cavity  123  previously destroyed. 
     It may be considered that the pocket of resin  123  disposed within this site  124  constitutes a removable axial fixing means, since it can be replaced very simply. Moreover, when it is removed, the transverse positioning of the bar  8  with respect to the openings  16 ,  16 ′ is not altered. 
     FIGS. 8 and 9 illustrate two additional variant embodiments of the invention. In FIG. 8, the bar  208  presents a constant diameter over the whole of its length. The outer periphery of its ends  208 B,  208 B′ is not coated with an anti-adhesive varnish, but is surrounded by an annular ring  228 , for example made of metal. 
     The bar surrounded by these rings is therefore sealed by the resin, then screws  222  similar to those,  22 , of FIGS. 3 and 4, are mounted. After having removed at least one of these screws, the bar  208  may be easily removed from the support  6 , by sliding within the ring  228  located on the side where the screw is absent. 
     In FIG. 9, the bar  308  also has a constant diameter over the whole of its length. Its ends  308 B,  308 B′ comprise a bevel or shoulder  310 . The outer periphery of its ends  308 B,  308 B′ is not coated with anti-adhesive varnish, but is surrounded by a bevelled ring  328  of which the profile is conjugate with that of ends  308 B,  308 B′. The bar  308  is sealed to the support  6 , being provided with these rings  328 , by casting liners of resin  321 ,  321 ′ similar to those shown in FIGS. 5 to  7 . In order to remove the bar  308 , at least one of the pockets  323  of resin is broken and the bar  308  may be easily removed from the support  6 , by sliding inside the ring disposed on the side where the pocket is broken.