FR2689289A1 - Moving band publicity unit with supporting and tensioning rollers at either end of housing - has guide rollers with flared ends adjacent to return rollers for better tension - Google Patents

Abstract

The unit consists of a housing (1) with supporting rollers (2, 4) for the moving band (10), connected to drives (6, 8, 19, 20) to move the band from one end of the housing to the other, and tensioners (14, 16, 17, 18) for the band. The unit has first and second guide bars (41, 42) with their axes parallel to those of the supporting rollers and situated adjacent to return rollers (11, 12) at the two ends of the housing. The guide bars have ends (45, 46) which are of greater diameter than their central portions and against which the edges (47, 48) of the band rub as it travels across the housing, and the end and central sections of the guide bars are joined by smoothly curved surfaces. ADVANTAGE - Improved band tension during operation.

Description

BELT DISPLAY DEVICE WITH GUIDE STRUCTURE
The present invention relates to automatic display devices comprising means making it possible to scroll a strip carrying advertising messages, the strip being stretched between two rotating strip-carrying rollers with parallel axes offset with respect to each other and on which rolls up or unrolls the tape.

 Such a display device is for example described in the document FR-A-2 589 272, in which a first strip-carrying roller is rotatably mounted on a frame along a first fixed axis, and a second strip-carrying roller is mounted rotatable on the frame along a second fixed axis parallel to the first fixed axis and away from it. A first motor is mechanically coupled to the first roller, and a second motor is mechanically coupled to the second roller. A display support strip ge, fixed at its first end to the first roller, is fixed at its second end to the second roller. Connection and switching means supply the first and second motors alternately from an external source of electrical energy, for winding the strip alternately in one direction and in the other.

 It appears that, with such a device, the strip carrying indications and advertising messages is not correctly stretched and guided between the two strip rollers.

 Another solution has been proposed in document FR-A-2 413 302, by passing the strip over several idler rollers mounted on sliding carriages biased by tensioning means. This mechanically feasible solution, however, leads to a very great complexity of the device, and to a great difficulty of use in particular when it comes to changing the band. The lateral guidance of the strip turns out to be insufficient.

 In known devices with a moving carrier strip, it can be seen that the strip rarely remains centered on the middle part of the strip-carrying rollers, but that it tends, on the contrary, to move progressively on one side or the other of the part median along the axis of the rollers. It is further noted that this lateral offset of the strip is not regular, but that it depends on various parameters such as for example the flatness of the ground on which the device rests, or such as the position and the density of the advertising inscriptions. worn on the tape itself.

 A second problem is that, in certain cases, the strip tends to crumple and to have longitudinal folds.

 To avoid the progressive lateral shift of the strip, an attempt has been made to provide means for adjusting the orientation of the band rollers or the deflection rollers. However, such a solution proves unsuitable for solving the problem of the random shifting of the strip in an axial direction or in the other axial direction of the rollers.

And such a solution does not eliminate the appearance of zones of longitudinal folds on the strip.

 The object of the present invention is to avoid the drawbacks of known devices, by proposing a new structure for a moving strip device in which the strip remains permanently in the immediate vicinity of a position centered transversely on a longitudinal center line, and in which does not show any longitudinal folds in the strip.

 For this, the invention results first of all from careful observation of random defects in the centering of the strip or the fold of the strip. During these observations, it was noted that the progressive strip offsets on the strip-carrying rollers depend in particular on the presence and the nature of the advertising inscriptions carried by the strip. It seems that these inscriptions, which are most often formed by additional layers of material glued to the strip or painted on the strip, constitute an excess thickness and locally modify the elasticity of the strip. I1 results in differential tensions and differential band elongations, unevenly distributed along the width of the band. Depending on the distribution of the advertising inscriptions carried by the strip, these differential elongations and these differential tensions induce a progressive shift of the strip during its winding on one or the other of the rolls carrying the strip. The progressive shift of the strip also depends on possible deformations of the chassis carrying the strip-carrying rollers, inducing variations in relative inclinations of the roller axes with respect to each other.

 On the other hand, in the case of strips of relatively large width, for example of strips whose width is equal to about one meter or more, transverse slippages of certain parts of the strip may occur on the strip-carrying rollers or the deflection rollers. When such a slip occurs over only a portion of the strip width, this results in a longitudinal fold zone along the connection line between the strip zone which has slipped relative to the roller and the strip zone which has not slipped.

 For this, according to a first aspect, the invention provides means ensuring permanent centering of the strip in the vicinity of a median transverse position of the strip.

 An advantage of the invention is to increase the useful strip surface. In fact, in known devices, the progressive and random transverse shift of the strip means that a whole area close to each of the longitudinal strip edges has to be obscured, in order to avoid making apparent -the strip edge or even an unoccupied area. by the band. The fact that, according to the invention, the progressive and random lateral movement of the band is avoided, - makes it possible to leave practically the entire bandwidth visible, so that all this width can be used to have advertising markings fully visible in the appropriate visible area of the device.

 According to another aspect of the invention, the device is further provided with means for preventing the formation of longitudinal folds in the fold of the strip, or for making them disappear.

 To achieve these and other objects, the strip display device according to the invention comprises - a frame, - a first strip-carrying roller rotatably mounted on the frame along a first fixed axis, - a second roller strip rotatably mounted on the frame along a second fixed axis substantially parallel to and away from the first fixed axis, - drive means, mechanically coupled to the first band roller and to the second band roller, for driving said rollers strip holder alternately rotating in one direction and the other during periods of travel, and to brake them during periods of standstill, - a display support strip, fixed at its first end to the first strip roller , fixed at its second end to the second strip-carrying roller, and wound around the strip-carrying rollers, so that the rotation of said strip-carrying rollers produces the movement of the intermediate strip part between said strip-carrying rollers, - tensioning means for tensioning the strip in its path between the strip-carrying rollers, - two intermediate deflection rollers between which extends a central strip of strip whose external face is visible from the outside of the frame, - a first guide bar and a second guide bar, with respective axes parallel to the axes of the strip-carrying rollers, and arranged respectively in the vicinity of the first deflection roller and in the vicinity of the second deflection roller to constitute two supports fixed against which the inner face of the central strip ply slides, said guide bars having flared end portions against which the two respective edges of the strip rub, so that the strip is returned to the middle position and is wound up thus regularly on the band rollers.

 According to a particular embodiment, each guide bar is fixed in rotation and in translation on the frame, and includes a smooth central portion of substantially circular section tangentially connected at each end to the corresponding flared end part by a surface of concave O-ring connection.

 Preferably, the bar is held on the frame by two fixed elements respectively retaining each of its ends, and it is also held on the frame by an intermediate fixed element secured to its central part. The intermediate fixed element pushes the central bar portion in the direction of the strip perpendicular to the central strip ply, so that the central bar portion is slightly bent and ensures the unfolding of the strip.

 Other objects, characteristics and advantages of the present invention will emerge from the following description of particular embodiments, given in relation to the appended figures, among which - FIG. 1 is a schematic perspective view and in partial section of a strip display device according to a particular embodiment of the present invention - Figures 2 to 5 schematically show, in top view, the stages of operation of the main organs of the device according to the embodiment of Figure 1 - the Figure 6 shows on a larger scale an embodiment of a guide bar inserted in the device of Figure 1; and FIG. 7 illustrates on a larger scale the relative positioning of a guide bar according to the invention in the device of FIG. 1.

 In the embodiment illustrated in FIG. 1, the device according to the invention comprises a frame 1, a first strip-carrying roller 2 rotatably mounted on the frame along a first fixed axis 3, and a second strip-carrying roller 4 mounted rotatable on the frame 1 along a second fixed axis 5 parallel to the first axis and away from the latter. A first electric motor 6 is mechanically coupled to the first strip-carrying roller 2 to rotate it internally by means of a mechanical transmission 7. A second electric motor 8 is mechanically coupled to the second strip-carrying roller 4 by the through a second mechanical transmission 9. A display support strip 10 is stretched between the first strip-carrying roller 2 and the second strip-carrying roller 4, its first end being fixed to the first strip-carrying roller 2, its second end being fixed to the second band roller 4. The band 10 is wound several turns around the band rolls 2 and / or 4.

 In the particular embodiment shown in this figure, the strip 10, from the first strip-carrying roller 2, passes over a first deflection roller 11, then over a second deflection roller 12, the deflection rollers 11 and 12 having axes substantially parallel to axes 3 and 5 of the tape-carrying rollers 2 and 4, and being spaced from one another. The central strip ply 10 extending between the deflection rollers 11 and 12 is arranged along one of the faces of the frame 1, visible from the outside and intended to make the indications and advertising messages carried on the face visible to the user. tape exterior 10.

 The strip 10 must remain permanently tensioned, and the device therefore comprises tensioning means. For example, in the embodiment shown, the first secondary web 13 of strip 10, extending between the first strip-carrying roller 2 and the first deflection roller 11, passes over a first tensioning roller 14. Optionally, the second secondary ply 15 of strip 10, extending between the second strip-carrying roller 4 and the second deflection roller 12, passes over a second tensioning roller 16. Each of the tensioning rollers 14 and 16 is rotatable on a respective axis substantially parallel to the axes 3 and 5 of the tape-carrying rollers 2 and 4, is laterally displaceable according to an appropriate stroke, and is urged by respective elastic return means 17 and 18 schematically shown pressing it against the corresponding secondary ply 13 or 15 of tape. Preferably, the inclination of the deflection rollers 11 and 12 is adjustable.

 A first brake 19 is mechanically coupled to the first electric motor 6 to brake it, and a second brake 20 is mechanically coupled to the second electric motor 8 to brake it.

 According to this embodiment, to ensure the continuous tension of the strip 10, a simultaneous supply of the two electric motors 6 and 8 is ensured, the motor driving the strip-carrying roller on which the strip must be wound, called the winding, being supplied at nominal voltage, the other motor driving the band roller from which the strip must unwind, called the unwinding motor, being supplied at lower voltage and in a connection such that the second motor exerts a holding torque s' opposing reeling. The brakes 19 and 20 are blocked to ensure the braking of the corresponding motor in all the stages of non-supply of said motor, and are released in all stages of supply of said motor.

 It is necessary, according to this embodiment, that the mechanical transmissions 7 and 9, between the respective electric motors 6 and 8 and the respective band-carrying rollers 2 and 4, be of the reversible type, such as a gear transmission, or toothed belt. This means that each of the electric motors 6 or 8 must be able to drive the corresponding tape-carrying roller 2 or 4 when it acts as a winding motor driving the roller on which the tape must be wound, and that each of the motors 6 or 8 must be able to be driven by the corresponding tape-carrying roller 2 or 4 when it acts as an unwinding motor coupled to the roller out of which the tape has to unwind.

 The device operates in both directions of tape travel. Thus, FIG. 3 illustrates a step for scrolling the strip 10 in a first direction represented by the arrow 21, while FIG. 5 shows a step for scrolling the strip 10 in a second direction represented by the arrow 22.

 In the step of FIG. 3, the strip 10 must gradually wind up on the second strip-carrying roller 4 and gradually unwind from the first strip-carrying roller 2. The winding motor is then the motor 8 coupled to the second strip-carrying roller 4, and it is supplied at nominal voltage to provide a nominal winding torque represented by the large arrow 23. The motor 6, coupled to the first strip-carrying roller 2, is then the unwinding motor, and is powered by a reduced voltage producing a reduced reverse torque represented by the small arrow 24.

 Conversely, in the step of FIG. 5, the strip 10 must gradually wind up on the first strip-carrying roller 2 and gradually unwind from the second strip-carrying roller 4. In this case, the motor 6 mechanically coupled to the first band roller 2 is the winding motor, and is supplied at nominal voltage to produce a nominal winding torque represented by the large arrow 25. The motor 8 mechanically coupled to the second band roller 4 is then the motor unwinding, supplied at reduced voltage to produce a reduced reverse torque represented by the small arrow 26.

 FIG. 2 represents an initial intermediate stage, prior to the stage in FIG. 3. During this initial intermediate stage, the two brakes 19 and 20 are released simultaneously, and only the unwinding motor 6 is supplied to produce, on the unwinding roller 2 or first strip-carrying roller, the reduced torque 24 reverses the desired direction of travel of the strip 10.

This initial intermediate stage is prolonged for a predetermined lag time, the duration of which may advantageously be between 1 and 3 tenths of a second approximately.

 Likewise, before the step of FIG. 5, a prior step shown in FIG. 4 is used, during which the two brakes 19 and 20 are released simultaneously, and the unwinding motor 8 coupled to the second roller is supplied alone. strip holder 4 to produce the reduced torque 26 reverses the desired direction of travel of the strip 10.

 Optionally, during the previous steps shown in Figures 2 or 4, the brake of the winding motor is released after the brake of the unwinding motor, at the end of the predetermined shift delay.

 In the embodiment which has been described, the device comprises two tensioning rollers 14 and 16. However, it is possible to design a simplified device, comprising only one of the two rollers 14 or 16.

 The device according to the invention comprises a first guide bar 41 and a second guide bar 42. The respective axes of the guide bars 41 and 42 are parallel to the axes 3 and 5 of the tape-carrying rollers 2 and 4. The first bar guide 41 is disposed in the vicinity of the first deflection roller 11, slightly offset with respect to this first deflection roller 11 in the direction of the second deflection roller 12. Similarly, the second guide bar 42 is disposed in the vicinity of the second roller guide 12, slightly offset from this second roller in the direction of the first guide roller II. The two guide bars 41 and 42 form two fixed supports against which the inner face of the central web 43 of tape slides.

 Each guide bar such as the bar 41 comprises a cylindrical central portion 44 of substantially circular section, connecting at each end to an end portion 45 or 46 with a larger or flared section, the end portion against which the one of the two respective longitudinal edges 47 or 48 of the strip 10.

 FIG. 6 illustrates a particular embodiment of the guide bars 41 or 42. In this embodiment, the bar 41 comprises a central cylindrical portion 44 of circular section, tangentially connecting at each end to a corresponding flared end portion 45 or 46 by a concave toric connection surface, respectively 49 or 50. The central portion 44 has a length L1 slightly less than the width of the strip 10, as shown in the figure, so that the edges 47 and 48 of strip can come to bear simultaneously against one and the other of the toric connection surfaces 49 and 50.

 In this embodiment, the bar 41 is fixed in rotation on the frame 1. Its central portion 44 is smooth. The bar 41 is held on the frame 1 by two fixed elements respectively retaining each of its ends, and by an intermediate fixed element 51 holding its central part. Thus, the inner face of the strip 10 rubs against said guide bar 41 when the strip scrolls.

 Preferably, the intermediate fixed element 51 pushes the central part of the bar 41 in the direction of the strip 10, perpendicular to the central ply 43 of the strip. Thus, the central portion 44 of bar 41 is slightly curved, for example by a few tenths of a millimeter, which produces an effect of unfolding of the strip 10.

 In the case of a device intended to receive a strip whose width is approximately one meter, one can for example use a guide bar 41 whose dimensions are as follows - the central portion 44 of the bar is shorter by about one centimeter the bandwidth - the central portion 44 of the bar has a diameter of about 22 millimeters - the end portions 45 or 46 of the bar have a diameter of about 50 millimeters - the concave O-ring connecting surfaces 49 or 50 have a radius profile of approximately 11 millimeters.

 To obtain a sufficient guiding effect, the guide bars 41 and 42 must push the central ply 43 of tape slightly beyond the plane formed by the contact generators of the deflection rollers 11 and 12. This arrangement is illustrated in the figure 7. In the case of a strip whose width is approximately one meter and whose length is approximately 3 meters, the following approximate dimensions can be chosen: the support generator 53 of the bar 41 is spaced the corresponding contact generator 52 of the deflection roller 11 at a distance L3 of approximately 55 millimeters, while its support generator 53 protrudes from the contact generator 52 at a distance L2 of approximately 3 to 5 millimeters, the plane of the central web of strip 43 thus being advanced by this distance L2 relative to the contact generators such as the contact generator 52 of the deflection roller 11.

 In the above embodiment, the two bars 41 and 42 are fixed, and the strip rubs against their bearing generators such as the generator 53. The edges 47 and 48 of the strip 10 rub against the connection surfaces 49 and 50, ensuring permanent centering of the strip 10 relative to a central position. In this way, the frame 1 may include an anterior opening 54 whose width is almost equal to the total width of the strip 10, without the risk of one or other of the edges 47 or 48 appearing. band 10.

 According to another embodiment, the guide bars 41 or 42 can be devoid of flared ends such as the ends 45 or 46, the bars then comprising other means for centering and guiding the strip. These other means may for example comprise two zones, situated on either side of the center of the bar, each of these zones being provided with helical ribs or grooves with opposite steps. For example, in Figure 6, there is schematically shown, in dotted lines, an upper bar area provided with helical grooves or ribs 54 with a pitch oriented in the direction tending to bring the upper edge 47 towards the center of the bar when the strip 10 scrolls towards the rear of the figure, the lower area of the bar having ribs or grooves 55 in opposite steps to bring the lower edge 48 of strip closer to the center of the bar when the strip runs in the same direction backwards of the figure. In this case, the bar produces a re-centering effect of the strip when the strip passes towards the strip-carrying roller corresponding to said bar.

 When scrolling in the opposite direction, the ribs or grooves 54 and 55 tend to cause the strip to diverge, away from its central position. To avoid this effect, provision can be made for the guide bar 41 to be rotatably mounted on its axis between two determined angular positions: in the first angular position, the guide bar 41 bears against the inner face of the strip 10 by a smooth surface; in the second angular position, the guide bar 41 bears against the inner face of the strip by the two surfaces comprising the ribs or helical grooves 54 and 55 with opposite steps tending to bias the strip halves towards the middle position.

 The present invention is not limited to the embodiments which have been explicitly described, but it includes the various variants and generalizations thereof contained in the field of claims below.

Claims (10)

 1 - Strip display device, comprising - a frame (1), - a first strip-carrying roller (2) rotatably mounted on the frame (1) along a first fixed axis (3), - a second carrying roller strip (4) rotatably mounted on the frame (1) along a second fixed axis (5) substantially parallel to and away from the first fixed axis (3), - the driving means (6, 8, 19, 20), mechanically coupled to the first strip-carrying roller (2) and to the second strip-carrying roller (4), for driving said strip-carrying rollers in rotation alternately in one direction and in the other during periods of travel, and to brake them during periods of standstill, - a display support strip (10), fixed at its first end to the first strip-carrying roller (2), fixed at its second end to the second strip-carrying roller (4) , and wrapped around the band rollers (2, 4), so that the rotation of said band rollers (2, 4) produces the movement of the interm tape ediary between said tape-carrying rollers (2, 4), - tensioning means (14, 16, 17, 18) for tensioning the tape (10) in its path between the tape-carrying rollers (2, 4), - two intermediate deflection rollers (11, 12) between which extends a central web of tape (43) whose outer face is visible from the outside of the frame (1), characterized in that it further comprises - a first guide bar (41) and a second guide bar (42), of respective axes parallel to the axes of the strip-carrying rollers (2, 4), and respectively disposed in the vicinity of the first deflection roller (11) and in the vicinity of the second deflection roller (12) to form two fixed supports against which the inner face of the central web of tape (43) slides, said guide bars (41, 42) comprising end portions (45, 46) flared against which the respective two edges (47, 48) of the strip (10) rub, so that the strip (10) is biased ée in the middle position and is thus wound regularly on the tape-carrying rollers (2, 4).  2 - Device according to claim 1, characterized in that each guide bar (41, 42) comprises a central portion (44) cylindrical with circular section, tangentially connecting at each end to the corresponding flared end part (45, 46) by a concave O-ring connection surface (49, 50).  3 - Device according to claim 2, characterized in that said central portion (44) of guide bar (41) has a length L1 slightly less than the width of the strip (10), so that the edges (47, 48 ) of the strip can come to bear simultaneously against one and the other of the toric connection surfaces (49, 50).  4 - Device according to claim 3, characterized in that - the guide bar (41) is fixed in rotation on the frame (1), - its central portion (44) is smooth, so that the inner face of the strip ( 10) rubs against said smooth guide bar (41) when said strip (10) runs.  5 - Device according to claim 4, characterized in that the guide bar (41) is held on the frame (1) by two fixed elements respectively retaining each of its ends.  6 - Device according to claim 5, characterized in that the guide bar (41) is further held on the frame (1) by an intermediate fixed element (51) holding its central part.  7 - Device according to claim 6, characterized in that the intermediate fixed element (51) pushes the central bar part (44) towards the strip (10) perpendicular to the central strip ply (43), so that the central portion of the guide bar (41) is slightly curved, and produces an effect of unfolding of the strip (10).  8 - Device according to any one of claims 3 to 7, characterized in that - the central bar portion (44) is shorter by about one centimeter than the strip width (10), - the central bar portion (44) has a diameter of approximately 22 millimeters, - the bar end part (45, 46) has a diameter of approximately 50 millimeters, - the concave O-ring connection surface (49, 50) has a profile of radius equal to approximately 11 millimeters.  9 - Device according to any one of claims 1 to 8, characterized in that the support generator (53) of the guide bar (41) is distant from the contact generator (52) of the corresponding deflection roller ( 11) at a distance L3 of approximately 55 millimeters, its support generator (53) projecting from the corresponding contact generator (52) of the deflection roller (11) at a distance L2 equal to approximately 3 to 5 millimeters.  10 - Device according to any one of claims 1 to 3, characterized in that - the guide bar (41) is rotatable on its axis between two determined angular positions, - in the first angular position, the guide bar (41 ) door against the inner strip face (10) by a smooth surface, - in the second angular position, the guide bar (41) bears against the inner strip face (10) by two surfaces having helical ribs or grooves (54, 55) with opposite steps tending to push the halves of the strip towards the longitudinal center line.