APPARATUS FOR OPENING SIGNATURES TO BE SUPPLIED TO A BINDING MACHINE

Abstract: Apparatus for opening signatures comprises a conveyor (1) having a concave section (1′) onto which, in use, the sig­ natures to be opened are deposited. Above this concave sec­ tion (1′) of the conveyor (1) there is disposed a series of rotat­ ing suckers (10) mounted on a movable frame (8) which is joined to a mechanism for displacing it with a reciprocating arcuate movement which follows the curve of the concave section (1′) of the conveyor (1). The said rotating suckers (10) are carried on bars (9) mounted eccentrically and rotatably on associated suction heads (7). These bars (9) are hollow and communicate, through a duct (11), with a suction device (12) controlled by a solenoid valve. Each of the said eccentric bars (9) is driven to rotate by a spindle (13) to which is rigidly con­ nected a sprocket (14) engaged by a slidable chain which acts as a rack. The apparatus is further provided with blower dev­ ices (16) operated whenever the suckers (10) are connected to the vacuum source, for the purpose of preventing unwanted raising of sheets of the signatures other than the one sucked up by the sucker (10).

Description: The present invention relates to apparatus for opening signatures intended to be supplied to binding machines; in particular the invention relates to improved signature-opening apparatus capable of operating at a high rate. As is known, for supplying certain types of binding machines, for example stitching machines, it is necessary first to open the signatures at their centre, and this must be done regardless of the number of sheets or additional tables of which the signatures themselves are composed. This operation is currently performed by means of machines equipped with suckers which operate by taking the individual signatures from a magazine and opening them sheet by sheet using the suckers until reaching the middle; the signatures are then disposed with the opening oriented downwardly straddling a saddle. Such known machines, however, have certain functional disadvantages because of the delicacy of the operations which they perform. In particular, a major disadvantage is the limitation of the speed of "manipulation" of the signatures, which is imposed by the structure of the known machines and the way they operate. Any attempt to increase the speed of operation of currently known commercially available machines would result in an increase in the speed of movement of the suckers which lift the sheets and, therefore, an increase in the speed and violence with which the sheets are raised and curved back. In practice, therefore, the possibility of making known machines operate faster is prevented by the machanical characteristics of the paper and the geometrical characteristics of the signatures (that is possible warping, planarity defects, direction of the fibres etc..). For example an apparatus according to the preamble of claim 1 is disclosed in the DE-A-1 945 501 reference. The present invention seeks therefore to overcome or at least reduce the disadvantages and limitations of previously known signature-opening machines by providing improved apparatus for opening signatures, which will be able to perform this operation more easily, more certainly and more rapidly. According to the present invention the above arm is achieved by an natures, having the features of the characterizing portion of claim 1. A particular advantage of the present invention is that of providing improved apparatus for opening signatures, which is capable of treating a greater number of signatures in a given unit of time than has been possible with conventional signature-opening machines. One embodiment of the invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic side view of a signature-opening machine formed as an embodiment of the invention; Figure 2 is a schematic side view of the movable assembly of the embodiment, carrying the rotating sucker heads; Figure 3 is a schematic side view showing the manner of operation of the apparatus of the present invention; Figure 4 is a perspective view showing one of the rotating sucker heads, together with the associated linkage for affecting movement thereof; Figure 5 is a sectional view showing the structure of one of the said rotating sucker heads; and Figure 6 is a set of diagrams schematically illustrating the sequence of operations of the heads themselves. Referring now to the drawings, the improved apparatus for opening signatures comprises an endless conveyor belt 1 carried substantially between two drums 2,3 and having an upper section 1′ which follows an arcuate path which is upwardly concave. Because of this arrangement, signatures 4 taken by means of gripper members 5, of known type from a magazine 6 and released onto the conveyor 1, are forced to assume a slight curvature which gives them a greater rigidity in the transverse sense. Above the upwardly concave arcuate section 1′ of the conveyor 1 three are positioned a plurality of sucker heads 7 mounted on a frame 8 having the same curvature as the said concave arcuate section 1′ of the conveyor 1. Each of the sucker heads 7 carries a respective hollow eccentric bar 9 on which is or are fitted one or more suckers 10 in communication, through a duct 11 with a suction device controlled by a solenoid valve 12, (see. Figure 5). The said eccentric bar 9 is connected to a spindle 13 which carries a sprocket 14 for rotation therewith, which sprocket engages a slidable chain 15 which acts as a rack causing rotation of the sprocket 14 and thus of the spindle 13 upon linear displacement of the chain 15. A blower device 16 is provided in association with each eccentric bar 9, and is positioned, as shown in Figure 5, to direct a stream of air parallel to the sheets of the signatures. The blower 16 is activated when the suction of the sucker 10 is commenced, and acts to cause the sheets to separate easily thus preventing unwanted raising of other sheets of the signature. As can be seen in Figure 2, the frame 8 carrying the rotating sucker heads 7 is linked by a rod to an arm 17 carrying a cam follower on which acts a cam 18 which is so shaped as to cause the frame 8 to perform a periodic reciprocating movement guided by two articulated link arms 19. The control mechanisms for the mechanical movement of the frame 8 carrying the sucker heads 7 and for the activation of the suckers 10 and the blowers 16 are synchronised with one another in such a way that the frame 8 is moving in the same direction as the signatures when the suckers 10 are connected to the suction source so that the uppermost sheet of a signature is raised and turned back by the movement of the head 7. Subsequently, during the return movement of the frame 8 the suckers are no longer connected to the suction source, but still act in cooperation with auxiliary means, to maintain the signature open. By means of this arrangement the relative speed of the signatures and the suckers is reduced so that each signature effectively "sees" the suckers roll at a speed lower than the speed of advancement of the conveyor. Thus, at a given speed of transport, there will be a more delicate working. Moreover, since the signatures are slightly curved by the concave curvature of the conveyor 1 they are, as previously indicated, more rigid in a transverse sense, and thus automatically better able to resist transverse flexure making the operation of the rotating suckers in raising the sheets more certain. Obviously, the number of suckers (or sets of suckers) provided over the length of the conveyor section 1′ will be matched to the number of sheets in the signatures to be opened so that the appropriate number of sheets can be raised to open the signatures in the middle. Moreover, if, because of particular mechanical requirements the individual suckers (or sets of suckers if there are a plurality on each bar 9) must be joined in two or more groups, the movable frame will also be provided with a suitable number of continuity elements such as those shown in Figures 3 and 6 and indicated with the reference numeral 20, operable to prevent the re-closure of the signatures as they move between adjacent suckers or sets of suckers. It is appropriate to state that the active phase of the suckers occurs during that movement of the movable frame 8 when the axes about which they rotate follow the signatures. In the apparatus of the present invention there are further provided grippers 21, known per se, operable to secure the signatures onto the conveyor, and retainer members 22, 23, also of known type, operable to grip the lower half of the signature itself to position it correctly straddling a saddle 24.

Claims: 1. Apparatus for opening signatures, comprising a closed loop conveyor (1) onto which signatures (4) to be opened are deposited in use of the apparatus, a plurality of rotatable sucker members (10) disposed above a conveyor section (1′) and mounted on a support frame, characterized in that said conveyor has a concavely curved section (1′) onto which signatures (4) to be opened are deposited and that the sucker members (10) are mounted on a support frame (8) connected to drive means for causing it to perform a reciprocating arcuate movement which follows the curve of the concave section (1′) of the conveyor (1). 2. Apparatus for opening signatures, according to Claim 1, characterized in that said rotatable sucker members (10) are mounted on bars (9) carried eccentrically on and rotatably coupled to respective suction heads (7), said mounting bars (9) being hollow and being put into communication by a duct (11) with a suction device (12) controlled by a solenoid valve. 3. Apparatus for opening signatures, according to Claim 2, characterized in that each said eccentric bar (9) is mounted on a spindle (13) to which is rigidly connected a sprocket (14) engageable by a slidable chain (15) serving as a rack to cause turning movement of the bar (9) about the spindle (13). 4. Apparatus for opening signatures, according to any of Claims 1 to 3, characterized in that a blower (16) is provided adjacent each said sucker member (10), the apparatus including control means for activating the blowers (16) whenever the associated sucker (10) is in operation, for preventing unwanted raising of sheets of signatures other than the sheet engaged by the sucker (10). 5. Apparatus for opening signatures, according to any of the preceding claims, characterized in that said movable support frame (8) carrying the suction heads (7) is linked to a displacement mechanism including a pivoted arm (17) engaged by a cam (18), and constrained by articulated link arms (19) to perform arcuate reciprocating movements. 6. Apparatus for opening signatures, according to any preceding claims, characterized in that the control means for determining activation of the sucker members (10) is phased to activate the sucker members when the support frame is moving in the same direction as the signatures (4) on the arcuately curved conveyor section (1′). 7. Apparatus for opening signatures, according to Claim 1, characterized in that there are further provided means for maintaining the signatures (4) in the open state after said suckers (10) have been disconnected from the suction source. 8. Apparatus for opening signatures, according to any preceding Claim, characterized in that said rotatable suckers (10) are joined in groups and there are further provided continuity elements (20) between adjacent groups of suckers (10) and operable to prevent re-closure of the signatures as they are moved on the conveyor (1) from one group of suckers (10) to another.

Inventors: MASURI, ANTONIO
Applicants: TEC-GRAF S.R.L.
Application year: 1986
Main classification: B65H5
IPC codes: B65H5