IL99228A - Device for perpetually changing posters - Google Patents

Description

PERPETUALLY POSTER CHANGING DEVICE -ABSTRACT The invention relates to a device which exhibits posters which are continuously and perpetually exchanged. A carrier foil is wound off a roller onto a second roller in one direction or is wound off the second roller in a different direction to be wound on the said first roller. The carrying foil carries a multiple number of posters, the positions of different posters being indicated by signs which signs being adapted to issue signals of positions by a sensor arrangement. By means of a special drive of the rollers there is obtained that the foil is uniformly moved between the rollers in both senses of its movement and is permanently stretched.

The present invention relates to Poster Exhibi ting and Changing Device wherein a carrying foi l is wound off a rol ler to be wound on a second rol ler or is wound off the second rol ler onto the said first one , first in one direction of movement and in the second case in the opposite direction of movement, poster being fixable to the carrying foil at predetermined locations thereon, the said locations being provided with markings which locations are adapted to be fixed by means of sensor arrangements to issue position signals monitoring the movement of the foil , A poster changing device of that type has been described by the specification of WO 89/03 570, According to that description the foi l 1s guided intermediate the two winding rol lers by means of two preposed guide and direction reversing rol lers the distance between which i s substantial ly the same as the width of one of the posters. The reversing rol lers guide the foil with the posters thereon behind a transparent pane of a casing in which the device is located* The sensor arrangement indicates the arrival at a proper posi tion of a poster, such that the drive provided for moving the carrying foil could be stopped for a period of time during which period1 the shown poster may be inspected. Thus , the foi l is advanced stepwise from poster position to poster position, both directions of movement of the foil being useful ly employed, where the posters are spread over a large area and at a great number of posters on the carrying foi l some difficulties might be experienced with the drive of the winding rol ler, since it would no longer suffice to apply a drive to the winding rol ler onto which the foil is wound. It would not be - 1 - certain that the foi l wi th the poster in the respective "inspecting" position would Be uniformly stretched behind the transparent pane.

Additional ly, relative with the diameter of the wound foi l , the veloci ty of motion of the foil would change.

The German Specification DE 30 50 464 describes a drive for fi lm devices which also employ winding rol lers . The rol lers are each associated with a polarity reverser of current in both directions of rotation of employed electromotors , The polarity of the currents are chosen such that the electromotor which i s placed advancely in the sense of rotative movement does pul l the fi lm whi le the fol lower electromotor brakes the fi lm. Apart from that there are provided individual motor controls for each of the electromotors which regularize the performance of the electromotor subject to the exi stent winding diameter of the fi lms relative to the polarity and capacit of the currents in a manner that the veloci ty of movement of a fi lm remains independent of the direction of movement and the positions at which the moving film arrives are substantial ly constant. Also in that arrangement the fi lm is moved conti nuously. Therefore thi s drive i s not sui ted to a poster changing device at which the carrying foi l bears posters at predetermined locations, so that the winding diameter does not continuously change but depends from attached posters on the foil . Moreover, at a poster changing device the carrying foi l has to be adjustable to rest at every poster position. > - 2 - It is the object of the invention to create a poster changing device of the previously mentioned type which includes a drive arrangement of the kind known and employed in film technique and allows a stepw†sely advancing of the carrying foil in both movement senses into a coveted position, the unequal application of posters to the foil and the consequent inexactitude of the winding diameter still permitting an exact positioning of the posters, These objects are obtained, according to the invention, thereby that each winding roller is associated with an electromotor which is driven in both directions due to a polarity reverser, that the polarities of currents of the motors are chosen in each one of the two directions of the carrying foil such that the advanced electromotor, in the sense of movement of the foil pulls the carrying foil while the following motor in the sense of movement of the foil brakes the carrying foil, that to each electromotor 1s added an individual motor control including a program memory which latter regularize the polarity and the amperage in dependence from a position of the carrying foil in such a manner that the velocity of movement and the said position of the foil remains substantially constant, that the current fed to the motor which is advanced in sense of direction of foil movement does decrease stepwise, while current fed to the following motor increases stepwise, that each electromotor is couple'd with the respective winding roller over a gear and is connected via a position reversing means with the respective motor control, that the sensor arrangement issues a reference position signal whenever the - 3 - carrying foil at a movement direction assumes a final position which is external to the last position at that direction and issues a position signal whenever one of the positions is reacted, that the sensor arrangement, transmits the reference position signal and the position signals to both motor controls, that the motor controls do control the positions via the position returning means and transmit the reference position signal and the position signals to a central processor, that each motor control has stored in the associated memory respective current strengths for each position of the carrier foil at both directions of movement for the respective motor stating the polarity and that the processor gives to the motor controls an advance step signal or a return step signal which is adapted to be used for moving the carrying foil into one of the two directions, At a stepwise adaptation of current subject to a reached position, the irregular changes of winding diameter during the movement of the carrying foil could be compensated such that there still would be obtained a constant speed of the moving foil. The returning of positions of motor control constitutes a simple possibility of ensuring whether the signals Issued by the processor are processed by the motor controls that the position indicated by the processor is actually reached, i.e. that there is present a kind of synchronism between processor and motor controls, It is obligatory for that purpose that the reference position signal and the position signals are transmitted to the processor and to the motor controls. Then only, the motor controls as well as the central processor are "aware" of the reached position, so that from any position any other position could be approached in one or another direction of movement. - 4 - A kind of continuous run over a number of positions can be effected thereby that the processor transmits to the motor controls, in addition to the step signal also a forward wind signal which is adapted to cause the, continuous run of the carrying foil, or additionally to a return step signal gives a return wind signal which would cause the run in the second direction of movement, According to one embodiment it is planned that the reference position signal , the position signals, the forward step signal, the return step signal, the forward wind signal, and the return step signal are of an impulse like kind, the processor transmitting the forward step signal, the return step signal, the forward wind signal and the return wind signal to the motor control via associated control lines and an adaptation connection, Particularly the control is effected thereby that the processor causes the two motor controls to advance the carrying foil by one position in the first direction of movement and the controls take from their memories the predetermined polarities and amperage of currents for the electromotors, transmitting them to the latter and that the processor causes the two motqr controls by means of the impulse like return signal to return the carrying foil by one position in the second direction of movement, and that the processor - by means of the advance wind signal and the simultaneous advance step signal - causes the two motor control to impart a continuous run to the carrying foil in the first direction of movement and also that the processor -with the return wind signal and simultaneous return step signal causes the two motor . 5 - controls to Impart continuous run of the carryi ng foi l in the second direction of movement and that the motor controls take from their program memories the predetermined polarities and amperages for the electromotor and transmi t them to the latter.

The procedure can be effected in a simple manner thereby that the processor is programmed for different successions of posters and that individual programs are choosable at fixed periods of time.

The invention wi l l now be described with relation to the drawings which exempl ify a practical embodiment.

Fi g. 1 is a schematical view of a poster change device.

F1g. 2 is a block sketch of a drive for the device.

Ftg, 3 i l lustrates schematical ly the path of currents in both electromotors .

Fig. 4 shows , also schematical ly the current in both electromotors at both directions of movement of the carrying foi l .

The device comprises a carying foil 5 which is transportable between two winding rol lers 1 and 2 in a first direction V and a second direction R. The rol lers 1 and 2 are driven by electromotors Ml and M2. At commencement of the run in direction V the carrying foi l is being wound on rol ler 1 and off rol ler 2. At commencement of the run in direction R the carrying foi l 5 i s being wound on rol ler 2 and off roller 1. The end posi tions of foi l 5 may be indicated by markings which di ffer from the position markings 10 ( 1 to n) of the carrying foi l at distances of e.g. equal to the width of base markings of end positions of the foi l .

The carrying fo†l 5 is guided intermediate of the two rollers 1,2 by idle rollers 3,4 which are positioned close to a transparent pane of a casing, The distance between rollers is substantially the same as that of a poster 8 which is held to the carrying foil 5 by fixing strips 7 which are provided at distances from another, equal to the width of poster 8. The width of foil 5 is slightly more than the height of poster 8, such that e.g. at the lowermost margin markings 10 could be placed. The strip 7 are connected with the carrying foil 5 by a web 9 only, such that the form rabbets at -both their sides for the reception of slid in posters. The poster B could be held additionally in an electro-static manner, Winding rollers 1 and 2 are driven via gears 13 and 15 by electromotors M2 and Ml which are coupled with the rollers, When the carrying foil 5 is transported in direction V the motor Ml drives the roller 2 contra-clockwisely the carrying foil 5 is then being pulled and is wound on the roller 2. The electromotor M2 is under current would be driving the roller 1 clockwise, which however is impossible since the movement of pull at the foil 5 overcomes and allows only movement of the carrying foil in the direction V, the result being braking action of electromotor M2 causing stretching of the carrying foil 5 especially in the section between the rollers 3 and 4. - be Should the carrying foil 5/ transported in the direction R, the electromotor M2 would pull the foil 5 while electromotor Ml does brake and keep the carrying foil in stretched state. Electromotor M2 revolves clockwise and Ml anticlockwise. However there occurs change, depending on a reached position and acutely present winding diameter at roller 1,2, of amperage. This will be made clear in relation to the description of Figs 3 and 4. - 7 - There should also be mentioned that in the example of Fig. 1 the on- and off winding of the carrying foil 5 occurs at mutually opposite outer sides of rollers 1,2.

The on- and off movement of carrying foil 5 could also occur on and off the mutually one another facing inner sides of rollers 1,2. In that case the winding directions of the rollers 1,2 and therewith the polarity of current opposite in mutual sense. By choosing the direction of revolution and polarity of current the on and off run at one roller could be at the outer and at the other roller at the inside thereof.

As may be gathered from Fig. 2, a sensor arrangement 11 issues a reference position signal io and position signal ip at an adaptation connection IF which transforms it and transmits it to motor controls MSI and MS2.

The reference position signal io is issued when an end position of carrying foil 5 in the first or second movement direction V and R is reached. This reference position signal io arrives at the motor controls MSI and MS2 and via those to a central processor p and serves the statement of a defined starting position from which the positions 1-n can be counted and become marked by markings 10. At possible overshooting of one markings 10, the sensor arrangements 11 issues an impulse like position signal ip.

The position signals ip are counted in the motor controls MSI and MS2 are.themselves checked since they exhibit a position return conduction RF and thereby a fresh position 1 to n, - 8 - ( The processor R can be programmed for different poster successions, the succession being chosen to become effective at certain time intervals. Since the processor receives the reference position signal and the position signals ip, the chosen position is "known" to It. For the control of the run the processor P may issue four signals in accordance with the succession of posters. These are an advance step signal Bv, a return step signal Br, an advance wind signal Spv and a return wind signal Spr.

All these signals are directed in the form of impulses via distinct conduits via the adaptation connection IF to the motor controls MSI and MS2.

In case that only the advance step signal Bv is given, it will be effective in both motor controls MSI and MS2 to advance the carrier foil 5 †n direction V by one position. To this end the motor controls MSI and MS2, being fully aware of position chose polarities and amperage JM1 and JM2 for the electromotors Ml and M2 in order to transport the carrying foil 5 at substantially constant speed to the next following position 1n direction V. The sensor arrangement 11 indicates that the new position has been reached. Further issuing of advance step signals BV is dependent on succession of posters which includes time interval, In case, however, that the processor P would direct to the motor controls MSI and MS2 a return step signal Br there would be caused in a similar manner, the movement of the carrying foil 5 in direction R by one position. The motor controls MSI and MS2 receive the necessary current according to polarity and amperage from their storage memories wherein -for both direction V and R - the currents are provided according to amperage and polarity for individual positions. - 9 - In case that the processor P issues simultaneously the advance step signal Bv and the advance wind signal Spv to the motor controls MSI and MS2 that would mean the continuous run of the carrying foil 5 in direction V. The continuous run can take effect either continuously or stepwise, The motor control MSI and MS2 and the processor P are informed about the position reached.

In a similar way the continuous run of the carrying foil 5 takes place in direction R when processor P issues simultaneously return step signal 3r and return wind signal Spr, A variation could be that only the advance wind signal Spv is given and the return wind signal Spr sufficient for the continuous run in the directions V and R while at additional issue of advance step signal Bv and return step signal Br respectively continuous about stepwise run in direction V and R is effected.

In these cases a continuous run may be effected to reach one specific position only.

So as to have the speed of movement of the carrying foil 5 as constant as possible and the carrying foil 5 is kept in stretched state in the section between the rollers 1,2 the, control of the electromotor Ml and M2 is activated at direction V by means of current according to Fig. 3 and in direction R by currents according to Fig. 4. In Fig. 3 it is assumed that the carrying foil 5 is wound fully on roller 1 and that a positive current does turn a roller in anticlockwise direction and a negative current in clockwise directio. Since roller 2 must pull the carrying foil 5 in direction V the electromotor Ml receives positive current Jml and electromotor M2 negative current JM2 which brakes the - 10 - roller, Fig, 3 shows what should be the amperage of currents Jml and Jm2 as depending on positions in order to equalize, the changing diameter DW of rollers 1 and 2, such that the carrying foil 5 intermediate rollers 1 and 2 is Of substantially constant speed when being moved from position to position. At such time the short periods of initial start and stops of the electromotors is neglected.

The dependence of current Jml and Jm2 shown in Fig. 3 have been indicated linearly for the sake of simplicity because the number of revolutions of electromotor Ml and M2 is substantially proportional with supplied current and the winding diameter DW together with number of revolutions influence inter alia the length of travel of foil 5 for one change of poster, The function Jml=f (DW) and Jm2=f (DW) could be of whatever form and for the positions 1-n required currents Jml and Jm2 which change stepwise, could be indicated non linearly, Fig, 3 now shows that at commencement of movement in direction V the current Jml is maximal and decreases from position to position, while current Jm2 starts from zero and increases from position to position .

In the direction of movement R the current Jm2 starts with maximal value and decreases stepwise from position to position. It should be remarked in that connection that numbering of positions of carrying foil 5 has to be in that case in opposite order, i.e. always in direction of movement o% the carrying foil 5. The current Jml now increases stepwise, ~ starting from zero.

It is thus obtained that the increase and decrease of winding diameters Dw of rollers 1 and 2 is compensated by unwinding of carrying foil 5 in both directions V and R is uniform and tension of foil 5 is effective between rollers 1 and 2. - 11

Claims (1)

1. CLAIMS; 1, A poster changing deylce of the type referred to 1n the preamble of the present description characterised thereby; that each winding roller Is associated with an electromotor which is driven in both directions due to a polarity reverser, that the polarities of currents of the motors are chosen in each one of the two directions of the carrying foil and that the advanced electromotor, in the sense of movement of the foil pulls the carrying foil while the following motor in the sense of movement of the foil brakes the carrying f oi 1 , that to each electromotor is added an individual motor control including a program memory which latter regularize the polarity and the amperage In dependence from a position of the carrying foil in such a manner that the velocity of movement and the said position of the foil remains substantiall constant, that the current fed to the motor which is advanced in sense of direction of foil movement does decrease stepwise, while current fed to the following motor increases stepwise, that each electromotor 1s coupled^ith the respective winding roller via a gear and s connected via a position reversing means with the respective motor control , that the sensor arrangement Issues a reference position signal whenever the carrying foil at a movement direction assumes a final position which 1s external to the last position at that direction and Issues a position si nal whenever one of the positions is reached, - 12 that the sensor arrangement transmits the reference position signal and the position signals to both motor control s , that the motor control s do control the positions via the position returning means and transmit the reference position signal and the position signals to a central processor, that each motor control has stored in the associated memory respective current strengths for each position of the carrier foi l at both directions of movement for the respective motor stating the polari ty, and that the processor gives to the motor controls an advance step signal or a return step signal which is adapted to be used for moving the carrying foil into one of the two directions , 2, Poster changing device according to claim 1 characteri sed thereby that the processor issues to the motor controls , apart from advance step signal also an advance wind signal which can be employed to cause a continuous run of the carrying foi l* in its first direction of movement or †n addition to a return run step signal issues a return wind signal which is employable to cause conti nuous run of the carrying foi l in i ts second direction of movement, 3, Poster changing device according to claim 2 characterised thereby that the reference position signal , the position signal , the advance wind signal and the return wind signal are impulse l ike, the processor transmitting the advance step signal , the return step signal , the advance wind signal and the return wind signal to the motor controls via associated control conduits and an adaptation conduit. ^ 13 - 4, Poster changt.ng device according to claim 3 characterised thereby that the processor causes by means of an impulse like advance signal that the two motor controls effect the move of the carrying foil by one position in the first direction of movement and thereby that the motor controls take the predetermined polarities and amperages for the electromotor from their storage memories and transmit the former to the electromotor, 5, Poster changing device according to claim 3 characterised thereby that the processor causes by means of the impulse like return step signal that both motor controls return the carrying foil by one position 1n the second direction of movement and thereby that the motor controls take from their storage memories the respective predetermined polarities and amperages for the electromotor and transmit them to the electromotors, 6, Poster changing device according to claim 3 characterised thereby that the processor causes by means of the impulse like advance wind signal and the simultaneous advance step signal - the carrying foil to run continuously in the first direction of movement and thereby that motor control take the relative,, predetermined polarities and amperages from their storage memories and transmit them to the electromotors, 7, Poster changing device according to claim 3 characterised tbarefcy that the processor causes that the moto controls by means of the return wind signal and the simultaneous return step signal effect continuous run of the carrying foil in the second direction of movement and that the motor controls take from their storage memories the relative predetermined polarities and amperages and transmit these to the electromotors. - 14 - 8, Poster changing deyice according to any one of claims 1-7 characterised thereBy that processor is programmed for different successions of posters and that the individual programs are choosabie at time intervals , » 15 -