US 3854158 A
An apparatus for binding groups of loose perforated sheets for albums, copy-books, calendars and the like, with a series of interconnected C-shaped binders formed directly from a wire feeding reel. Selecting, prefixing and numbering of loops to be cut and inserted into the sheets to be bound are automatically achieved by electronic control devices. Coupling between binder elements and sheets is statically accomplished by manually placing the sheets to be bound in a given position and by operating a press, for example, by means of a foot control lever or of the same group of sheets. The apparatus is designed also for inserting in one single group of perforated sheets two spaced multiple loop segments whose mutual distance and number of loops can be previously adjusted.
Description (OCR text may contain errors)
[ 1 Dec. 17,1974
11/1 AX ll/lA ll/lA ll/lA 3,334,918 8/1967 Pigna et 3,451,081 6/1969 Liouvllle 1/1971 Seaborn 6 /1962 APPARATUS FOR BINDING LOOSE PERFORATED SHEETS FOR ALBUMS,
Primary ExaminerLawrence Charles  ABSTRACT An apparatus for binding groups of loose perforated sheets for albums, copy-books, calendars and the like,
COPY-BOOKS, CALENDARS AND THE LIKE  Inventors: Daniele Pesenti Pigna, Bergamo;
' Antonio Camozzi, Alzano Lombardo, all of Italy  Cartiere Paolo Pigna, S.p.A., Alzano Lombardo, Italy Assignee:
with a series of interconnected C-shaped binders formed directly from a wire feeding reel. Selecting, prefixing and numbering of loops to be cut and inserted into the sheets to be bound are-automatically achieved by electronic control devices. Coupling between binder elements and sheets is statically accomplished by manually placing the sheets to be'bound in a given position and by operating a press, for example, by means of a foot control lever or-of the same group of. sheets. The apparatus is designed also for inserting 9, 4 R 2 4 U. MB a t u a n D .mm y .m .h n r .U .m "m 7 m U .o m m a r t m H w mw mm 0 Wm Wu 0. M 3 n N w mu l R C e D. y s. n D. a .m N M N 22 3 55  Field of Search............................ 11/1 A, 1 AC in one single group of perforated sheets two spaced  References Cited multiple loop segments whose mutual distance and UNITED STATES PATENTS number of loops can be previously adjusted.
11 Claims, 6 Drawing Figures 2,240,903 5/1941 Freundlich.L....l...........r.. 11/] A PATENTEUBEEI 1 3,854,158 SHEET? [W5 Fig. 2
PAIENT min 1 7 I974 SHEET 3 OF 6 PATENTEU m 1 11974 3,854; 158
' SHEET 5 BF 6 Fig. '5
PAIENTED nu: 1 1 I974 SHEET 6 OF 6 APPARATUS FOR BINDING LOOSE PERFORATED SHEETS FOR ALBUMS, COPY-BOOKS, CALENDARS AND THE LIKE BACKGROUND OF THE INVENTION The present invention relates to an automatic apparatus for binding of loose perforated sheets for albums, copy-books, calendars, notebooks, memorandumbooks and so on.
Binder elements are known, which are available in the trade as reels of metallic wire optionally coated with plastic materials or enamelled, or also made out of plastic materials, substantially similar in shape to an open spiral, or to say it better, a sequence of open rings connected together, or even being of the so-called comb" type.
Automatic apparatus are also known which, without manual working, effect the binding of loose perforated sheets by means of said binder elements. These binder elements are already pre-cut or continuously and automatically fed from the wire reel. Such apparatus however, somewhat expensive and cumbersome are-mostly suitable where their almost continuous operation and high time production are required, i.e., for large printing works, paper factories and the like.
On the contrary, where as in small and medium size book binding and printing workshops, and in stationers shops the binding of albums, copy-books, calendars, catalogs, etc. is occasionally required and for small productions, the above-stated'apparatus are not at all suitable being too expensive and therefore the binding op eration has been manually carried out. v
It was necessary to previously cut or to buy already cut the binder elements at the desired length, to manually introduce them into the perforated sheets and to close them by a press. Naturally this has given rise to a high waste of time and a high employment of handwork so that the cost of each bound article has been considerably increased.
SUMMARY OF THE INVENTION It is'an object of the present invention to provide an apparatus for binding groups of perforated sheets with a series of interconnected C-shaped binder elements formed directly from the wire reel.
It is anotherobject of the present invention to provide a binding apparatus which allows the selection and the prefixing of the number of loops to be cut and inserted into the sheets, even discontinuously.
Therefore an important advantage of the apparatus according to the present invention is given by the fact that there is no need of pre-cut binder elements and then of theirstorage in different lengths according to the number of loops which are to be used for each bind- .attains satisfactory quantities, in respect of the purposes of these apparatus, which are considerably higher than that obtained through the manual method.
The semiautomatic apparatus according to' the present invention is characterized in that it comprises, in a housing and supporting frame, means for feeding a looped wire band from a feed reel, means for counting the number of loops of said band and for comparing such number with the number preset on an adjustable selector adapted to operate means for cutting the band, and means for inserting the cut band segment into holes provided in groups of loose perforated sheets positioned on the same apparatus at a coupling and closing station, means responsive to said positioning being provided and adapted to allow the feeding of the next multi-loop segment upon the actuation thereof due to said positioning and adapted to operate said feeding means when said responsive means is released upon the removal of said group of sheets from the coupling and closing station after the closing has been effected by said inserting means.
According to a preferred embodiment, two different operations are possible, a first of which provides for the insertion of only one multi-loop segment, having a given length, for each article to be bound and a second one, particularly suitable for calendars, in which the binding operation is accomplished, for each article, along two series of peripherical holes spaced apart so that at the middle of the sheets a free space is provided in order to allow the application for example of a fastening means of the calendar to a wall and so on. In this ing operation. Moreover, the insertion of the binder into the perforated sheets is automatically accomplished together with the closing under the press of the binder elementsUnlike automatic apparatus of the prior art, there is no dynamic coupling between binders and sheets, but the coupling statically occurs by manually placing the group of sheets to be bound in a given position and by operating the press, for example by means of a foot control lever on the same group of sheets. Instead, the feeding of the next multi-loop section and the cut of a number of loops prearranged on a suitable selector preferably consisting of electronic event, by the simple operation of a switch, every time two segments, having the same adjustable length, are fed,'which are spaced apart by a length also possibly adjustable.
BRIEF DESCRIPTION OF THE DRAWINGS Further objects, advantages and features of the apparatus according to the invention will be apparent to those skilled in the art from the following detailed description of a particular embodiment, given by say of a non-limiting example, with reference to the accompanying drawings, wherein:
FIG. 1 shows a perspective diagrammatic view of the apparatus according to the present invention;
FIG. 2 shows a diagrammatic view of the feeding device of the binding elements;
FIG. 3 shows a frontal partially sectional view of a de tail of the coupling and closing station of the binder elements with the perforated sheets;
FIG. 4 shows a sectional view taken along the line v lV-IV of FIG. 3;
FIG. 5 shows a diagram of the pneumatic circuit of the apparatus according to the present invention; and
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIG. 1, the apparatus according to the present invention is mounted on a supporting and covering frame 1. Feeding means (shown in FIG. 2 but not in FIG. 1) delivers an open wire binding strip 2 to the apparatus from a supply reel 3. Strip 2 has a generally C-shaped cross-sectional configuration and is formed by integrally-connected, parallel spaced looped prongs best illustrated in FIGS. 3 and 4. A sensing device 4 counts the loops passing thereunder and compares the counted number with a number programmed on a selector included in a control panel 5. When the programmed count is reached a cutting means 6 separates the counted loops from the strip. A press consisting of two metallic elements 7 and 7a is adapted to press the cut loops 'therebetween to cause the open loops to close at a coupling and closing station formed by two support shelves 8 and 8a for the sheets to be bound. I
With reference to FIG. 2, the strip feeding means comprises a toothed chain or belt 9 driven and guided by a set of rollers. Roller 10, by way of example, serves as a drive roller whereas the remaining rollers 11, 11a, 11b, 11c, and 11a are idler rollers. Between rollers 10 and 11 and between rollers 11b and 110, chain 9 is diverted on two idler transmission rollers 12 mounted on a movable plate 13. Plate 13 may be brought nearer to roller 11 without deviation; that is, strip 2 remains aligned with a front chain guide 9a. I
It is to be pointed'out that the unwinding of strip 2 from'supply reel 3 must be effected without deformation or stress in the strip. This is achieved by means of proximity switches, for example the three swiches illustrated in FIG. 1, bearing the reference numerals 16, 16a, 16b. These switches do not require direct contact for sensing the presence of the strip 2 at pre-established heights on an upright 17. The operation of the switches is as follows: middle switch 16 controls unreeling strip 2 at a normal speed; higher switch 16b controls unreeling at a higher speed since it is assumed that a quicker utilization of the strip occurs downstream; and lower switch 16a controls stopping of the supply reel 3. Strip 2 is driven along the front guide 9a past the loop counting device 4 (FIG. 1), for example a photoelectric cell device, which sends count pulses to a counter to be described in relation to FIG. 6. When the loop count is the same number as that programmed on selector 5, cutting device 6 causes the corresponding number of loops to be cut from the strip. The cut segment arrives at the coupling and closing station at which are located the two positioning shelves 8 and 8a for the sheets to be bound. Two movable blocks 18 and 18a are slidable along said shelves to define a reference position. The front edge of a stack of sheets to be bound, correspond- 2. When the bound sheets are withdrawn after actuation of the press, microswitch 21 initiates both feeding of the subsequent, already cut strip segment and cutting of another segment according to the number programmed by selector 5.
A strip segment, transferred automatically to the coupling and closing station at the end of the preceding operation cycle (or manually at the beginning of the first cycle), arrives in front of a stack of perforated sheets which has been arranged on the two shelves 8 and 8a. Actuation of a foot lever 22 by an operator, or of microswitch 21 by the sheets, causes the two elements 7, 7a of the press to be close. Referring to FIG. 4, the lower of the two open (i.e., C-shaped) ends of the loops of strip 2 is designed to pass through the perforated holes of sheets 23. Therefore the press stoke, in order to cause the coupling between strip 2 and the perforated sheets by closing the loops, should occur chiefly from the bottom. To this end the lower member 7a of the press usually has a greater stroke and/or speed than upper member 7 which acts substantially as an anvil.
Still referring to FIG. 4, parallel to and in front of the two press members 7 and 7a there are two movable walls 20 and 20a. The walls act as a front guide surface for strip 2 during the press stroke to prevent the ends of the loops from getting crushed in a position parallel to the stack of sheets by guiding the loop ends into the sheet holes. When the press is actuated the movable walls'20, 2011 close lightly to hold the loops, automatically adjusting their positions by proper elastic means (see FIG. 3) according to the thickness of the group of sheets. When the press opens walls 20, 200 return to their normal position.
With reference to FIG. 2, it is possible'for either single segments or double spaced segments of strip 2 to be inserted into each group of. perforated sheets. For single segment operation lever 14 is not operated by cylinder 15 and remains in the illustrated position wherein it does not cause movable plate 13 to slide. For double spaced segment operation, by merely actuating a switch provided on the control panel '5 a sequence of displacements of the lever 14 is brought about, resulting in the movement of plate 13. As willbe described more in detail hereinafter with reference to FIGS. 5 and 6, by operating switch A provided for this purpose on the control panel 5, cylinder 15 pushes lever 14 forward. This results in a sliding to the right of the section of toothed belt 9 which is between the pulleys 11 and 11d and a similar sliding of the binder elements which are in that section, while the driving roller 10 remains motionless. During. this displacement the next segment of strip 2 is cut and caused to move forward at a spaced distance (which may be adjustable) from the first segment, due to the displacement of the lever 14.
Upon operation of the press and release of microing to the edge remote from the perforations provided for binding, is aligned with this reference position. The perforated edge rests upon horizontal bar 19 provided with a microswitch 21 which senses the presence of the sheets. Upon positioning of the sheets on bar 19, microswitch 21 enables feeding of the next segment of strip sheets, lever 14 moves back to its initial (illustrated) position. This causes displacement to the left (in FIG. 2) of the toothed belt 9 section, between rollers 11 and 11d, resulting in a balancing of the previous displacement to the right but without affecting the positioning of the strip segments since in this situation the displaced belt section carries no binder elements. Subsequently the driving roller 10 moves up to bring another strip segment between rollers 11 and 11d so that the I equipment of the apparatus according to the present invention, which equipment is substantially housed inside control panel 5. The operation of the circuits .will be described hereinbelow with the understanding that a digital (not analog) systemis employed andtherefore the output and input voltages have strictly defined values (except for smallvoltage drops due to the loads, etc.). Thus, in the following description the voltage level 0 V is indicated by 0 (logic zero) and the voltage level l2 V dc. by. 1. (logic one), the meaning of which is well known in digital electronic language.
At starting, the switch (not shown) connecting power to the circuits being closed, all the devices of the circuit are oversized. Everytime this occurs the output of the general resetting device RG switches from O to l level for approximately 40 ms. This pulse clears the counter through the input 8 of the device AU andpresets the slow memories MLI, ML2 and ML3 through the respective inputs 7, 2, 2 so that the respective outputs attain the logic 1. This presets the apparatus in operation mode, i.e.: motor at rest and brake locked (logic 0 at the input l'of the static switches J 1F. and JOM, respectively, relating to the brake unlocking and to the motor actuation). The static switch J 1W, relating to the movable walls 20 and 20a, receives logic 1 at its input; therefore these walls hold the strip loops,
If the switch indicated by A on the front side of the control panel is in single binding position, corresponding to the position 1 of FIG. 6, a logic 0 is applied to input 2 of NAND-NOR gate N2, input7 of NAND- NOR gate N3X, and input 8 of slow memory MLl. This means that static switch I for spacing cylinder 15 is cut off, i.e., lever 14 remains at rest position.
Operation of the START" push-button Btwice consecutively places a logic 1 pulse at output 7 of monostable device M52, which, through slow-memory ML2 causes the static switch I 1W to cut off. Consequently wall 20, a (FIG. 4) close to assume the guide function for the binders. Simultaneously, this logic 1 pulse also reverses the memory ML3, changing its 0 output to logic 0" and thereby producing logic balance at the five-input block N2 (all inputs at logic 0). Therefore the 0 output of block N2 becomes logic 1- and the power stages 11F and 10M switch, thus unlocking the brake and starting the motor. In this situation the binders, drawn forward by the toothed belt 9, move into the inserting-area along the rail guide 9a.
As each binder loop moves forward, a pulse is produced by the photoelectric cell 4 (FIGS. 1 and 3) through suitable slits formed on the driving roller 10. These pulses reach the 0 input of block AU which operates as a feeder for the two decade counting devices DUI and DU2 and further as a filter and squaring device for the counting pulses. From the output 4 of the block AU the pulses reach the input of the first counting decade, i.e., of the first decade block DUl, from which the pulses, from number 0 to.9, come out coded through the outputs 6, 7, 8, 9 respectively. These outputs are connected with the inputs 6, 2, 7, 4 of the coding section relating to the first decade of a numerical selector S. Each tenth pulse counted at DUI is sent from output 2 to the input 3 of second decade DU2 where the pulse is counted in the same manner as in the first decade. The switches in selector S are manually set to the number corresponding to the required number of loops of a binding segment. When the selected count is reached, output 3 of the selector S provides a logic 0. The output 3 of selector S is connected to pin 4 of inverter N3Z which drives input 1 of the memory ML3. The latter switches and causes its output 0 to be switched from 0" to 1, whereby the motor stops and the brake isapplied through the static switches J 1F and JOM.
The logic level switching at the output 0 of block ML3 reaches, through inverter NV2 and devices N3Z and NV4, the input 5 of the monostable MS3. Therefore, at the output 7 of the monostable M83 a logic I pulse is provided for, approximately about ms. The static switch I lTpilots the magnetic valve E6 (see FIG. 5) during this pulse and the next sequence of loops is pre-cut by the cutting device 6 of FIG. 1.,
The cutting operation occurs at the end of each feeding cycle through the above described actuations. As the diagram clearly shows the cut may be also provided through the double manual operation (closing and subsequent opening), of the cutting push-button D on the front side of the control panel 5 (see FIGS. 1 and 6), but only when the motor is at rest. i As previously stated, at the end of each feeding cycle of the output 0 of the block ML3 becomes logic l and therefore the output 4 of the same memory block goes to logic 0 since the outputs of the ML blocks are complementary. This logic 0 reaches the input 2 of block NEW and enables the actuation of static switch I 1P relating to the operation of the press. Thus, by operation of the press foot lever 22 (see also FIG. 1) a logic level reversal is obtained. In addition, at input 1 of block N3Y logic 0is provided and therefore the press closes through the static switch J 1?, which enables the magnetic valve E7, for controlling the press operating cylinder C7 as long as the foot lever 22 is pressed.
When the foot lever, 22 has been released, the press opens since the input 1 of the static swtich JlP as well as the input 4 of the block N3X become logic 0. Therefore, at the inputs of this last block there is a logic 0" level balancing resulting in a logic,l at output pin 6. This operates static switch J 1W to drive a magnetic valve which causes the movable walls 20, 20a guiding the binder elements to open. This operation is required in order to allow the removing of the bound sheets 23 from the insertion zone.
As the diagram shows, the total operating cycle, as described from the setting of the switch A on the contact 1 and so on, may also occur through the micro switch 21, since its contact opens when the sheets to be bound are placed in the insertion zone, and closes again when the bound sheets are removed from said zone as above described. The advantage of this operation is easily understood since the feeding of the new binder elements occurs during the time in which the apparatus operator stores the bound sheets and takes the next group of sheets to be bound, with no idle time.
Alternatively, when a double binding for each group of sheets (i.e., with two spaced multi-loop segments) is desired, the switch A has to be set in position 2. Thus, input 2 of block N2 receives logic level, as do input 7 of block N3X and input 8 of memory MLl. These logic levels result in a change of the operation as so far described. This change resides in the fact that, at the end of a feeding cycle, besides performance of the cutting operation, the static switch J 15 is also enabled. This excites the magnetic valve E15 thus pushing the lever 14 through piston 15. This results, as above mentioned, in the sliding to the right of that binder segment, which is between the pulleys 11 and 11d. During this displacement the cut operation occurs, as already described with reference to the single binding operation, and as the lever 14 comes into contact with the limit switch FCl, opening the relevant contact, the motor starts again while at the same time the brake unlocks. This happens because the logic 0 at the input 5 of block MSl provides a pulse at its output 7, which pulse reaches input 7 of the block ML3, thereby driving the output 0 of the latter to logic 0. The logic 0 level at the input 50f block MSl also reaches the input' 4 of block N3Y thus creating a logic 0" level balancing. Thereby the output 6 of thesame block switches to logic I and a logic 1 condition exists at the inputs 7 and 8 of block N3Y. Then the output 9 of the latter and the input 8 of block N2 become logic level 0 and logic level 0 exists at all five inputs of the second groups of block N2. In this situation the motor is started and the brake is unlocked through the static switches JOM and 11F, respectively.
Consequently, the second binder section, consisting of the same number of loops as those of the first section, but spaced therefromby a length depending on the layer 14 displacement, is drawn forward. When the pulse relating to the last loop of the second binder section causes the motor to stop and blocks the brake, the cutting operation occurs and the adjustment of the press proceeds as already described as to the single binding operation.
Where the foot lever 22 operating the press is pushed, at the output 3 of the block N3Y the logic l level is obtained, controlling the magnetic valve E7 of the press through the switch J 1?. This logic l level also reaches input 9 of block MLl driving the output 0 of the same block to the logic 0 level, whereby the static switch 11S of the spacing device should be cutoff. This cut-off, however, does not occur since at the same time input 2 of switch J 1S reaches logic f 1 from output 9 of block N3X, this level being due to the fact that both the inputs of N3X are logic 0 since the same logic I due to the press operation not only reaches input 9 of the block MLl, but also input 1 of block ML2, thus driving output 4 of the latter to logic .0." In this way, at the inputs of the block N3X logic 0 level balancing is obtained, which causes output 9 of the same block to become logic I, preventing the static switch J 1S from being cut off. Therefore cylinder 15 remains at its forward position, as do lever 14 and plate 13.
Release of the foot lever 22 of the press causes output 3 of the block N3Y to become logic 0, i.e., the press opens. This logic 0" reaches input 4 of the block N3X where it provides a logic balancing, whereby the output 6 of N3X becomes logic l and enables static switch J 1W through its input 1. The latter operation causes movable walls and 20a to open and terminates the operating cycle for the double binding. Actually, the opening of the walls enables the booklet or calendar 23 to be removed, since the binder elements of the two sections have beenalready closed by the press throughout the holes of said booklet.
It is clear by the diagram that the static switch J IS, notwithstanding the end of the cycle, remains enabled since its input 2 holds the logic l level. Only by the pushing and the subsequent releasing'of the START push-button B, or through the removal of a booklet,
can the spacing device 15 be retracted back into the cycle starting position. Specifically, the logic l level at the output of block MS2 reverses the logic level at output 4 of block ML2. Therefore at the input 8 of block N3X the logic balancing is destroyed and then output 9 of N3X assumes a logic 0 level, i.e., the static switch J 15 is cut off and spacing cylinder 15 is retracted.
Only when cylinder 15 is retracted does the feeding step of the next cycle become enabled since, at the retracted position, the spacing device opens the limit switch FC2 and provides a logic 0 level balancing at the inputs 1 and 2 of the block N3X. This causes the brake to unlock (static switch J 1F) and the motor to start (static switch JOM) through the blocks N3X- and N2. Thus, what has been described for the double binding is repeated if the switch A is in the position 2, while if it is in the position 1 what has been described for the single binding is repeated.
If the apparatus has to be adjusted, it is necessary that the brake be unlocked without starting the motor. This is met by positioning the switch C on the front of the control panel 5, into brake unlock position, i.e., by closing the switch C of FIG. 6. In this way, a logic l level is obtained at the input 8 of the block N2 and therefore the cut off of the static switch JOM is also obtained. The logic l level reaches the input 2 of static switch J 1F and excites the circuit for unlocking the brake. The blocks AC of FIG. 6 are d.c., known devices.
For purposes of illustrating the association between the bound sheets and the binders produced by the present invention, reference is made to US. Pat. No. 3,334,918 to Pigna et al.
It is obvious that possible additions and/or modifications may be made by those skilled in the art to the abovedescn'bed and illustrated embodiment of the apparatus according to this invention, without departing from the scope thereof. Particularly, not pneumatic actuating means could be provided, such as mechanical or electromagnetic means, as well as electronic control circuits different from those herein described and illustratedf What we claim is:
l. A semi-automatic apparatus for binding loose sheets perforated along one edge, comprising:
a feed reel for storing a wire band configured as a series C-shaped loops;
feed means for feeding said wire band from said feed reel along a predetermined feed path;
counter means for counting the number of loops of said wire band which are fed from said feed reel; actuable cutter means for cutting the fed wire band into binder segments;
selector means for permitting manual selection of the number of said loops to be included in a binder segment;
comparator means arranged to compare the counted number at said counter means and the selected number at said selector means, and to terminate feeding by said feed means and actuate said cutter means when the two numbers are equal;
means for resetting said counter means when said cutter means is actuated;
a coupling station located along said feed path in cluding means for receiving a stack of said loose perforated sheets when manually inserted into said station transversely'of said feed path such that the perforated edges of said sheets enter said C- shaped" loops;
actuable press means for closing the C-shaped loops at said coupling station about the perforated edges of the sheets in said stack; and
control means responsive to absence of predetermined positioning of said sheets at said coupling station for inhibiting. operation of said press means, and responsive to removal of a stack of sheets from said predetermined positioning at said coupling station for re-initiating wire band feed by said feed means.
2. An apparatus according to claim 1, wherein said feed means comprises a toothed belt driven by various pulleys, one of which is a driving self-limiting pulley.
3. An apparatus according to claim 2 further comprising:
two pairs of adjacent pulleys;
two transmission idler pulleys mounted on a plate which is movable in plane of said feed path;
a lever for moving said plate;
operable means for actuating said lever to move said plate and bring said idler pulleys nearer to one or the other of said pairs of pulleys, wherein said toothed belt passes in its path between said two pairs of adjacent pulleys, on said two idler pulleys such that said movable plate and said two idler pulleys can be brought near to one or another of said two pairs of pulleys, one of which comprises said driving self-limiting pulley.
4. An apparatus according to claim 2, wherein said driving pulley is provided with slits on its upper surface for each loop drawn by said toothed belt, and said counting means comprises a photoelectric cell mounted near said driving pulley for sending a pulse for each slit of said pulley.
5. An apparatus according to claim 1, wherein said press means comprises two vertically movable press elements adapted to cause the open loops of said binding spiral to pass through the perforation of the predeterminedly positioned sheets at said coupling station and adapted to close said loops wherein said means for receiving includes a pair of vertically-spaced verticallymovable walls for guiding and making easier the predetermined positioning of said sheets.
6. An apparatus according to claim 5, wherein the lower element of the press means is adapted to move upwards at the closing of the press means by a longer stroke length and with a higher velocity than the upper element of the press moves downwards, the closing of said loops being provided from'the bottom.
7. An apparatus according to claim'S, further comprising an actuable press control member, and wherein said press is kept closed for the duration of actuation of said press control member which when released, controls the opening of said press elements and said movable walls, whereby to permit removal of said stack of sheets.
8. An apparatus according to claim 3, further comprising pre-arrangeable switching means for controlling the closing of at least one segment of loops having prefixed length. I
9. An apparatus according to claim 8, wherein two spaced binder segments can selectively be closed upon the same'group of sheets, said apparatus further comprising:
switch means operative at the end of the feeding operation of a first binder segment for operating said lever connected with said movable plate such that i said two idler pulleys mounted on said plate are pushed toward one of said two pairs of pulleys, whereby the toothed belt segment in correspondence with said coupling station is permitted to move forward only along the path between the two transmission pulleys and is out of contact with said driving pulley.
10. An apparatus according to claim 9, further comprising a limit switch operated by said lever at the end of its movement, and adapted to control the starting of said feed means thereby causing a' second binder segment to move towards said coupling station, said binder segment comprising the same number of loops as the first binder segment, such two segments being spaced apart by a length depending on the lever stroke length.
11. An apparatus according to claim 10, wherein said control means, when released upon the removal of a stack of sheets bound by two spaced apart binder segments, moves said operable means to retract said lever, therebycausing a displacement of said toothed belt segment in the direction opposite to the above said forward movement, whereby the starting position of the belt is restored.