Patent Publication Number: US-2021162647-A1

Title: Device for feeding preforms ha ving variable-position guide elements

Description:
TECHNICAL FIELD OF THE INVENTION 
     The invention relates to a device for supplying preforms, in particular preforms made of thermoplastic material intended to be shaped into containers, suitable for preforms comprising a collar, the device comprising a file-forming slide for the preforms, comprising two sliding tracks intended to support the preforms upright by their collar, the slide comprising: 
     a fixed frame; 
     elements for guiding the preforms, which elements are mounted so as to be adjustable in terms of position on the frame so as to be adapted to different formats of preform. 
     TECHNICAL BACKGROUND OF THE INVENTION 
     The supply device is designed to be implemented in an installation for blow-molding of containers made of thermoplastic material, such as polyethylene terephthalate (PET). 
     According to a well-known technique, containers of this kind are produced in two main steps. A first step involves injection molding of a preform made of thermoplastic material. This preform comprises an essentially tubular body which is closed at one of its axial ends. Once this injection molding operation has been completed, the other end of the preform has the final shape of the neck of the container. Generally, the neck of the container comprises a thread and, at its base, an annular support collar which projects radially outward relative to the neck and relative to the neck. 
     There are machines in which the preforms are sent directly to the blow-molding machine just after their injection molding, each preform being transported individually. 
     However, in numerous cases, the preforms are manufactured by injection molding at a first location and are blow-molded to the definitive shape of the container at a second location on a specific blow-molding machine. A technology of this kind makes it possible to carry out the blow-molding operation as close as possible to the bottling operation, since the injection-molding operation can be done anywhere. Indeed, it is relatively easy and cheap to transport preforms, whereas transportation of the containers after blow-molding has the drawback of being relatively uneconomical owing to the very large volume of the containers. 
     In the event that the injection molding machine and the blow-molding machine are two completely independent machines, the blow-molding machine has a preform supply device which is equipped with a system for sorting and aligning the preforms. 
     In such a system, the preforms are deposited in bulk into a trough. They are removed from this trough by an elevator belt which in turn deposits the preforms, at a predetermined rate, onto the upper end of orienting rollers, also termed aligning rollers. These two aligning rollers are inclined relative to the horizontal and they are essentially parallel to one another. The two rollers are driven in rotation in opposite directions, and are spaced apart from one another so as to leave a gap which is slightly larger than the diameter of the body of the preforms, but slightly smaller than the outer diameter of the support collar located at the base of the neck. 
     The orienting rollers are configured in such a way that, under the effect of gravity, the preforms are forced between the two rollers. Thus, simply by gravity, each preform tends to arrange itself between the two rollers, so as to be suspended by its collar between the rollers. The counter-rotation of the two rollers ensures that the preforms are positioned upright one behind the other, and the inclination of the rollers ensures that the preforms slide along the axis of the rollers, toward the bottom of the orienting rollers, where they are then recovered in a file-forming slide, which is itself connected to the blowing installation. 
     The file-forming slide for the preforms comprises a longitudinal slot which is bounded transversely by two parallel rails. 
     In the file-forming slide, the preforms accumulate in a continuous line. Normally, each preform tends to arrange itself upright in the slide, between the two parallel rails, in such a way that it is suspended by its collar on the rails. 
     The file-forming slide is configured in such a way that only perfectly positioned preforms are allowed to slide downward. To that end, the rails of the slide comprise numerous guiding elements which serve to ensure that only correctly positioned preforms can file along. Moreover, these guiding elements serve to guarantee that the preforms that have been received in the slide retain correct positioning until they arrive at the bottom of the slide. 
     To that end, the various guiding elements must be perfectly adjusted to the dimensions of the preform. 
     The installations for producing containers are designed to be able to receive preforms of different formats. To that end, the guiding elements are mounted so as to be adjustable in terms of position on the slide. In the case of a change of preform format, it is necessary to carry out numerous adjustments, in particular in order to make it possible to adjust the guiding elements to the dimensions of the new model of preform. 
     Such an adjustment operation is generally very time-consuming. Moreover, an adjustment error can result in stoppage of the installation for the time that it takes to rectify the position of the various guiding elements. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention proposes a device for supplying preforms, in particular preforms made of thermoplastic material intended to be shaped into containers, suitable for preforms comprising a collar, the device comprising a file-forming slide for the preforms, comprising two sliding tracks intended to support the preforms upright by their collar, the slide comprising: 
     a fixed frame; 
     elements for guiding the preforms, which elements are mounted so as to be adjustable in terms of position on the frame so as to be adapted to different formats of preform; 
     wherein the guiding elements are mounted so as to be adjustable on the frame by means of associated support plates, the support plates being fixed in a reference position on the frame by removable fastening means in order that the guiding elements can be detached from the frame by removing the support plates while keeping their adjustment in terms of position relative to the support plates. 
     According to other features of the invention: 
     the means for removable fastening of the support plates on the frame consist of quick-release fasteners; 
     the slide comprises a slot bounded transversely by two parallel guiding rails, each guiding rail comprising an under-neck guide, forming one of said guiding elements, which comprises one of the tracks for sliding, the under-neck guide being mounted so as to be adjustable transversely on the support plate by means of first adjustable fastening means; 
     each guiding rail comprises a body guide, forming one of said guiding elements, which is arranged below the under-neck guide in order to guide a body of the preforms and which is mounted so as to be adjustable transversely on the under-neck guide by means of second adjustable fastening means; 
     each guiding rail comprises a neck guide, forming one of said guiding elements, which is arranged on the under-neck guide in order to guide a neck of the preforms and which is mounted so as to be adjustable transversely on the under-neck guide by means of third fastening means; 
     the device also comprises at least one lip guide, forming one of said guiding elements, which is arranged in line with the slide in order to hold the preforms upright in the slide, the lip guide being mounted so as to be adjustable vertically on support plates by means of fourth adjustable fastening means, the support plates being fastened in a reference position on the frame by means of quick-release fasteners; 
     the quick-release fasteners are formed by nesting of complementary-shaped elements, comprising a ball locking mechanism; 
     the ball locking mechanism comprises a pusher for unlocking; 
     the quick-release fasteners are formed by ball-and-socket mechanisms; 
     at least one of the adjustable fastening means is formed by a clamping screw received in an adjustment port, the clamping screw comprising an imprint for cooperating with an adjustment key; 
     each guiding rail is formed of multiple independent segments which are each borne by associated support plates. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Further features and advantages of the invention will become apparent from reading the following detailed description, for the understanding of which reference will be made to the appended drawings, in which: 
         FIG. 1  is a schematic view in profile which shows a preform supply device comprising a file-forming slide that is created according to the teaching of the invention; 
         FIG. 2  is a schematic view in profile which shows a preform that can be taken on by the supply device of  FIG. 1 ; 
         FIG. 3  is a perspective view which shows a supply slide that is created according to the teaching of the invention, wherein the rails for guiding the preforms and the lip guide are mounted on the frame; 
         FIG. 4  is a view in perspective similar to that of  FIG. 3 , in which the lip guide is absent and in which the guiding rails are shown disassembled from the frame; 
         FIG. 5  is a view in perspective from above, which shows the rails for guiding the preforms mounted adjusted in position on their support plates, and which are intended to be mounted on the frame of the file-forming slide; 
         FIG. 6  is a view in vertical cross section along the plane of section  6 - 6  of  FIG. 5 ; 
         FIG. 7  is a view in vertical cross section along the plane of section  7 - 7  of  FIG. 5 ; 
         FIG. 8  is a view in vertical cross section along the plane of section  8 - 8  of  FIG. 5 ; 
         FIG. 9  is a view similar to that of  FIG. 4 , which shows the lip guide disassembled from the frame, the guiding rails being mounted on the frame; 
         FIG. 10  is a view in perspective, which shows the lip guide mounted adjusted in position on its support plates, and which is intended to be mounted on the frame of the file-forming slide; 
         FIG. 11  is a view in axial section along the plane of section  11 - 11  of  FIG. 3 , which shows the quick-release fasteners of the plates in the position mounted on the frame. 
     
    
    
     DETAILED DESCRIPTION OF THE FIGURES 
     In the rest of the description, elements that have an identical structure or similar function will be denoted by one and the same reference. 
     In the rest of the description, the orientations longitudinal, vertical and transverse will be adopted in a nonlimiting manner, these orientations being indicated by the trihedron “L, V, T” in the figures. In this case, the vertical direction is used by way of a geometric reference oriented perpendicular to the longitudinal axis of the file-forming slide. The direction of gravity is indicated by the arrow “G” of  FIG. 1 . As indicated at the start of the description, since the slide is inclined at a given angle to a horizontal plane, the vertical direction is in this case inclined at the same angle to the direction of gravity. 
     In the rest of the description, the term ‘interior’ will be used to qualify a face or a displacement directed transversely toward the central slot  27  of the file-forming slide  16 , while the term ‘exterior’ will refer to an opposite direction. 
       FIG. 1  shows, very schematically, a preform supplying device  10  that is intended for example to supply preforms  18  to a blow-molding installation  12 . The supplying device  10  comprises upper orienting rollers  14  between which preforms  18  are deposited in bulk at a rate determined by means which are not shown. 
     In the orienting rollers  14 , the preforms  18  are oriented neck-up and are arranged in a line in order to then be delivered to a file-forming slide  16  which transports the preforms  18  to the blow-molding installation  12 . An example of such orienting rollers  14  is described in detail in document EP-A1-1.335.870. Preforms  18  are thus received in the file-forming slide  16 . 
     The orienting rollers  14  have a slope of given inclination “α”, for example 12° to the horizontal, to allow the preforms  18  to slide to the entry of the file-forming slide  16  located below under the effect of gravity, while the file-forming slide  16  has a slope “β” of greater inclination, for example 15°. 
     As shown in  FIG. 2 , each preform  18  supplied to the blow-molding installation  12  has a tubular body  20  of axis “A” which is closed at its lower end. The body  20  is open axially upward via a cylindrical neck  22  which extends the body  20  upward. Where the neck  22  joins the body  20  there is a collar  24  which projects radially relative to the cylindrical segment of the neck  22  and relative to the body  20 . The collar  24  has an annular lower face  25  which has a free outer edge of outer diameter “D 1 ”. An internal edge of the face  25  below the intersection with the body  20  has an internal diameter, referred to hereafter as the under-neck diameter “D 2 ”. The body  20  further has, at a distance below the collar  24 , a diameter “D 3 ”. Finally, the neck  22  has a given axial height “H”. 
     The invention relates to the file-forming slide  16  for the preforms  18 . As shown in  FIG. 3 , the file-forming slide  16  comprises a frame  26  that is fixed relative to the ground. 
     The file-forming slide  16  comprises a longitudinal slot  27  which extends from an entry  30  to an exit  32  of the file-forming slide  16 . The exit  32  of the file-forming slide  16  is located below the entry  30  to allow the preforms  18  to slide toward the exit  32  under the effect of gravity. 
     The slot  27  is bounded transversely by two sliding tracks  34  that are intended to support the upright preform  18  by its collar  24 . In particular, the preform  18  is suspended between the two sliding tracks  34  by its collar  24 . 
     The file-forming slide  16  further comprises elements for guiding the preforms  18 . As will be explained in greater detail hereafter, the guiding elements are in this case formed by at least one under-neck guide  40  and/or at least one body guide  52  and/or at least one neck guide  62  and/or at least one lip guide  72 . 
     These guiding elements are mounted so as to be adjustable in terms of position on the frame  26  by adjustable fastening means, so as to be adapted to different formats of preform  18 . Indeed, it is important that the guiding elements be set as close as possible to the preforms  18  in order to ensure that the preforms  18  adopt a position that is perfectly suited to supplying the blow-molding installation  12  at the exit  32  of the slide  16 , and to ensure that the preforms  18  do not become stuck in the slide  16  as they file along. 
     The adjustment of the position of the various guiding elements must be done with great accuracy in order to avoid preforms becoming stuck as they slide along the guide elements. This operation is extremely time-consuming. 
     Moreover, it has been noted that numerous manufacturers of containers use a limited number of preforms  18 . However, even when adjustment has already been carried out for a given model of preform, it is difficult to return to that adjustment in a repeatable manner. 
     The invention proposes equipping the file-forming slide  16  with support plates  36  which are fixed in a reference position on associated reference positions  37  of the frame  26 . This means that the position of the support plates  36  is not adjustable with respect to the frame  26 . This ensures that each support plate  36  occupies said reference position when it is once again mounted on the frame  26  after having been removed. 
     Each element for guiding the preforms  18  is mounted so as to be adjustable on the frame  26  by means of at least one associated support plate  36 . Thus, each support plate  36  is designed to support at least one element for guiding the preforms  18 . Each guiding element is fastened so as to be adjustable in terms of position relative to the support plate  36  by associated adjustable fastening means. 
     In order to permit rapid replacement of the support plates  36  and of the associated guiding elements, each support plate  36  is also fastened to the frame  26  by means of quick-release fasteners  82 . These quick-release fasteners  82  are also known as “snap locks”. A quick-release fastener  82  of this kind makes it possible to install and remove the support plates  36  with economy of movement and without requiring the use of tools. 
     Since the guiding elements are fastened to the frame  26  so as to be adjustable, by means of the support plates  36 , the guiding elements can be removed from the frame  26  by rapid removal of the support plates  36  while retaining their setting in terms of position relative to the support plates  36  for a specific model of preform  18 . When said model of preform  18  is once again processed by the blow-molding installation  12 , the guiding elements and their support plate  36  may once again be mounted on the frame  26  with the appropriate setting, without the need for a new adjustment operation. 
     In the example shown in the figures, the file-forming slide  16  comprises two groups of guiding elements. 
     As shown in  FIGS. 4 and 5 , a first group of guiding elements is formed by two parallel guiding rails  38  which extend longitudinally on either side of the slot  27 . 
     As is shown in particular in  FIGS. 6 and 7 , each guiding rail  38  comprises a first guiding element formed by an under-neck guide  40 . The under-neck guide  40  takes the form of a horizontal plate. The under-neck guide  40  comprises the sliding track  34  which is formed on an interior longitudinal rim of an upper face  42  of the under-neck guide  40 . The sliding track  34  is intended to support the preforms  18  by their collar  24 . The under-neck guide  40  is mounted so as to be adjustable transversely on associated support plates  36  by means of first adjustable fastening means. The under-neck guide  40  of each guiding rail  38  is in this case divided in two or three independent segments in order to facilitate the replacement of the guiding rails  38 . The two longitudinal ends of each under-neck guide  40  segment are each adjustably fastened to an associated support plate  36 . 
     As is shown in  FIGS. 5 and 7 , each under-neck guide  40  is more particularly mounted so as to be able to slide transversely on the associated support plates  36  via the intermediary of vertical-axis clamping screws  44  which are received in longitudinal oblong openings  46  of the under-neck guide  40 . A free end of the clamping screws  44  is received in a complementary tapping of the support plate  36 . Thus, when the clamping screws  44  are loosened, the under-neck guide  40  is liable to slide transversely relative to the clamping screws  44  which are secured in the support plate  36 . When the clamping screws  44  are tightened, the under-neck guide  40  is immobilized in its adjusted position by being clamped between a head of the clamping screws  44  and an upper face of the support plate  36 . 
     Moreover, in order to permit very precise setting of the transverse position of the under-neck guide  40  relative to the support plate  36 , the support plate  36  comprises an adjustment screw  48  whose axis is transverse to the captive head which is only able to rotate about its axis relative to the support plate  36 , as is shown in  FIGS. 5 and 6 . A threaded shank of the adjustment screw  48  is received in an adjustment nut  50  which moves transversely as one with the under-neck guide  40 . Thus, by turning the adjustment screws  48 , it is possible to adjust with precision the transverse position of the under-neck guide relative to the support plate  36  when the clamping screws  44  are loosened. 
     Moreover, the adjustment nut  50  is in this case mounted so as to be adjustable in terms of vertical position relative to the under-neck guide  40  to make it possible to adjust the attitude and altitude of the under-neck guide  40  relative to the support plate  36 . 
     Moreover, each guiding rail  38  also comprises a second guiding element formed by a body guide  52  which is arranged beneath the associated under-neck guide  40 . This body guide  52  is intended to avoid the body  20  of the preforms  18  tipping transversely between the guiding rails  38 . 
     In order to make it possible to adapt the width of the transverse space enclosed between two body guides  52  on either side of the slot  27 , it is provided to mount the body guide  52  so as to be adjustable transversely on the under-neck guide  40  by means of second adjustable fastening means. Each body guide  52  has a longitudinal vertical guiding panel  54  that extends vertically downward from a lower face of the under-neck guide  40  and a horizontal fastening tab  56  which extends transversely outward from an upper end edge of the guiding panel  54 . 
     As is shown in particular in  FIGS. 5 and 8 , the second adjustable fastening means consist of vertical-axis clamping screws  58  which are received in a transversely extending oblong opening  60  of the under-neck guide  40 . A threaded end of the clamping screw  58  is received in an associated tapping of the fastening tab  56  of the body guide  52 , while a head of the clamping screw extends above the under-neck guide  40 . Thus, the transverse displacement of the body guide  52  relative to the under-neck guide  40  is guided by the transverse sliding of the shank of the clamping screw  58  in the oblong opening  60 . When the transverse position of the body guide  52  has been adjusted relative to the under-neck guide  40 , the clamping screws  58  are tightened so as to be able to immobilize the body guide  52  in the adjusted position relative to the under-neck guide  40  by clamping between the head of the clamping screw  58  and the fastening tab  56  of the body guide  52 . 
     Each body guide  52  is also divided into two or three segments, each of which is associated with a segment of the under-neck guide  40 . 
     Each guiding rail  38  also comprises a third guiding element formed by a neck guide  62  which is arranged on the under-neck guide  40 . The neck guides  62  serve to outwardly transversely delimit the sliding track  34 . This makes it possible, in particular, to avoid the preforms  18  moving transversely in the slot  27  as they file along. In this case, the neck guide  62  takes the form of a right-angle comprising a longitudinal vertical guiding flange  64  that extends vertically upward from the sliding track  43 , and a lower, horizontal fastening flange  66  that extends transversely towards the outside from the lower edge of the guiding flange  64 . 
     The neck guide  62  is mounted so as to be adjustable transversely on under-neck guide  40  by means of third adjustable fastening means. As is shown in  FIG. 5 , the third adjustable fastening means consist of vertical-axis clamping screws  68  which are received in an oblong opening  70  of the fastening flange  66  of the neck guide  62 . A threaded end of the clamping screw  68  is received in an associated tapping of the under-neck guide  40 , while a head of the clamping screw  68  extends above the fastening flange  66  of the neck guide  62 . Thus, the transverse displacement of the neck guide  62  relative to the under-neck guide  40  is guided by the transverse sliding of the shank of the clamping screw  68  in the oblong opening  70 . When the transverse position of the neck guide  62  has been adjusted relative to the under-neck guide  40 , the clamping screws  68  are tightened so as to be able to immobilize the neck guide  62  in the adjusted position relative to the under-neck guide  40  by clamping the fastening flange  66  of the neck guide  62  between the head of the clamping screw  68  and the under-neck guide  40 . 
     Each neck guide  62  is also divided into two or three segments, each of which is associated with a segment of the under-neck guide  40 . 
     As shown in  FIG. 4 , one of the guiding rails  38  is therefore formed of two independent segments  38 A,  38 B while the other guiding rail  38  is formed of three independent segments  38 C,  38 D,  38 E. Each segment  38 A to  38 E is borne by two associated support plates  36  arranged at its longitudinal ends. This makes it possible to simplify the handling of the support elements upon a change of preform  18 , as will be explained below. 
     A second group of guiding elements is formed by at least one lip guide  72 . As shown in  FIGS. 9 and 10 , the lip guide  72  is formed by a transverse longitudinal guiding plate which is arranged in line with the file-forming slide  16  in order to hold the necks  22  of the preforms  18  upright in the file-forming slide  16 . The lip guide  72  is mounted so as to be adjustable vertically on the frame  26  by means of fourth adjustable fastening means. This makes it possible to adapt the height of the lip guide  72  relative to the height “H” of the neck  22  such that the lip guide  72  is positioned as close as possible to the upper end of the neck  22  of the preforms  18  while allowing them to file along. 
     The lip guide  72  is mounted on the frame  26  via the intermediary of an associated support plate  36  so as to make it possible to detach the lip guide  72  from the frame  26  by rapid removal of the support plate  36  while retaining its position setting relative to the support plates  36 . 
     More particularly, the support plate  36  is formed by a longitudinal vertical plate which is arranged at a distance above the guiding rails  38 . To that end, the support plate  36  rests in this case on placements  37  that are arranged at height relative to the reference placements  37  of the support plates  36  of the guiding rail  38 . 
     The lip guide  72  is mounted so as to be adjustable vertically between the support plate  36  and the guiding rails  38  by means of suspension rods  74  which are received in orifices  76  of the support plate  36 . A lower end of the suspension rods  74  is fastened to the lip guide  72  while an upper end of the suspension rods  74 , projecting above the support plate  36 , is provided with a nut  78  that serves for adjusting the height of the lip guide  72 . A counter-nut  80 , located just below the support plate  36 , serves for vertically immobilizing the lip guide  72  relative to the support plate  36  by clamping when the lip guide  72  is adjusted in terms of position. 
     Moreover, the lip guide  72  is adjustable in terms of longitudinal position relative to the support plate  36 . To that end, the orifices  76  of the support plate  36  have a longitudinally elongate shape to make it possible to guide the lip guide  72  to slide longitudinally relative to the support plate  36 . 
     All of the support plates  36  are removably fastened to the frame  26  using quick-release fasteners  82 . Each support plate  36  for a segment of guiding rail  38  comprises in this case a single quick-release fastener  82 , while the support plate  36  for the lip guide  72  has in this case two quick-release fasteners  82 , each arranged at one longitudinal end of the support plate  36 . 
     According to the non-limiting example shown in  FIG. 11 , the quick-release fasteners  82  consist of axial nesting means provided with a ball locking mechanism. The quick-release fasteners  82  comprise a first part that is borne by the support plate  36  and a second part that is borne by the frame  26 . 
     The first part of the quick-release fastener  82  comprises a sleeve  84  of vertical axis “B” which forms a female nesting element. The sleeve  84  is fastened to an upper face  86  of the support plate  36 . Advantageously, the sleeve  84  forms a handle by means of which handling and positioning of the guiding elements on the frame  26  can be facilitated. 
     The sleeve  84  has a central orifice  88  which is arranged so as to coincide with an orifice  90  of the support plate  36 . The frame  26  comprises a vertical-axis pin  92  which projects vertically upward relative to the reference placement  37 . The pin  92  forms a male element that is intended to be nested vertically in the central orifice  88  of the sleeve  84 , passing through the orifice  90  of the support plate  36  when the latter is placed on the reference placement  37 . 
     This nesting is adjusted so that the support plate  36  can be immobilized radially in all directions relative to the frame  26 , while allowing the support plate  36  to slide vertically. 
     In order to vertically lock the sleeve  84  in the position where it is nested with the pin  92 , the sleeve  84  is fitted with locking balls  94  which are received so as to be able to move radially in recesses  96  created in the internal cylindrical wall that delimits the central orifice  88  of the sleeve  84 . The recesses  96  open radially toward the vertical axis of the sleeve  84 . The recesses  96  are designed in such a way that they hold the balls  94  captive while allowing them to move radially between a release position in which the balls  94  are entirely retracted in their recess  96  and a locking position in which the balls are pushed radially inward so that they project from the cylindrical wall of the central orifice  88  through the openings of the recesses  96 . 
     The pin  92  comprises a channel  98  that receives the balls  94  in their locking position in order to lock the sleeve  84  in the nested position. 
     The sleeve  84  further comprises means for controlling the balls, these being formed by a pusher  100  that is mounted so as to be able to slide vertically in the wall of the sleeve  84 . The pusher  100  has an upper horizontal core  102  which comprises, on its upper face, a central actuating button  104  that is accessible from the top of the sleeve  84  via a hole. 
     Vertical tabs  106  extend vertically downward from a peripheral edge of the core  102 . A free lower end of the tabs  106  is provided with a ramp  108  for controlling the balls  94 . These ramps  108  are arranged in a bottom of the recesses  96 . When the pusher is controlled in an upper position, the balls  94  are constrained by the ramps  108  toward their locking position, whereas when the pusher  100  is ordered into a lower position, the ramps  108  allow the balls  94  to slide toward their release position. 
     The pusher  100  is in this case returned to its upper locking position by an elastic member  110  which is interposed vertically between a face of the sleeve  84  and the lower end of the tabs  106 . The button  104  of the pusher  100  must be actuated so as to order the balls  94  into their release position. 
     According to one variant (not shown) of the invention, the pin is borne by the support plate, whereas the sleeve is borne by the frame. 
     According to another variant of the invention, the ball locking mechanism is borne by the pin rather than by the sleeve. 
     According to another variant of the invention, the balls can be replaced with other locking elements such as lugs. 
     According to one variant (not shown) of the invention, the quick-release fasteners consist are formed by ball-and-socket mechanisms. 
     When the file-forming slide  16  is first used with a new model of preform  18  that is to be processed recurrently, the guide rails  38  and the lip guide  72  are fastened to the frame  26  via the associated support plates  36  using the quick-release fasteners  82 . The axial nesting of the quick-release fasteners is symbolized by the vertical dashed lines in  FIGS. 4 and 9 . 
     The position of the various guiding elements, in particular the under-neck guide  40 , the body guide  52 , the neck guide  62  and the lip guide  72 , which is then set relative to the support plates  36  in order to adapt the dimensions of the slot  27  to the format of the preform  18 . Thus, the under-neck guides  40  are set transversely in such a way that the slot  27  that is enclosed between them has a transverse dimension that is slightly greater than the under-neck diameter “D 2 ” of the preform  18 . Then, the body guides  52  are set so as to adapt the width of the slot  27  to the diameter “D 3 ” of the body  20  of the preforms  18 . The positions of the neck guides  62  are also set so as to adapt the transverse spacing thereof according to the outer diameter “D 1 ” of the collar  24  of the preform  18 . Finally, the position of the lip guide  72  is also set vertically and longitudinally above the guiding rails  38  according to the height “H” of the neck  22  of the preform  18 . 
     When the position of each guiding element is set, it is immobilized in its set position by tightening of the clamping screws or of the corresponding clamping nuts. 
     Given that this operation is intended to be carried out just once, the clamping screws and the nuts comprise an imprint for cooperating with an adjustment key. Thus, in this case the adjustment operation requires the use of a tool. However, as a variant, the clamping screws comprise handles to permit manual, tool-free tightening. 
     When a change in the format of the preform  18  is desired, the segments of the guiding rail  38  and the lip guide  72  are removed from the frame  26  using the quick-release fasteners  82 . The adjustable fastening means are not loosened. The abovementioned guiding elements remain in position, set relative to the support plates  36 . The guiding elements are stored in their set position which is suitable for said preform format, until the next use of said format of preform  18 . 
     When said format of preform  18  is once again processed, the guiding elements are once again mounted on the frame  26  via the support plates  36  using the quick-release fasteners  82 . Thus, the guiding elements are already set for said format of preform  18 . It is therefore not necessary to carry out the setting operation again. 
     Moreover, the use of quick-release fasteners  82  for fastening the support plates  36  to the frame  26  permits very quick replacement of the guiding elements. 
     Furthermore, dividing each guiding rail  38  into independent segments serves to facilitate the handling of the guiding elements when changing the format of the preform  18 .