Device (clamp) for retaining rolls or logs by pressure in cutters for the production of toilet paper and other items

The pressure-retaining device or clamp acts on the roll or log adjacently to the cutting plane and may be adapted to various diameters of the material being processed; for each path of advance of the rolls or logs (B) and on each side of the cutting plane, it comprises: a pair of symmetrically curved flexible strips (12, 14) projecting from enclosing supports (9A, 10; 7A, 10) and having end portions able to move according to the variation in the diameter of the roll, and a strap (22) fixed to elastic return holders (24A) and adjusting holders, said strap surrounding the pair of strips (12, 14) so as to vary their geometry in relation to the variation in the diameter of the material being processed.

The invention relates to a device for retaining material by pressure 
adjacently to the cutting plane, for cutters of rolls or logs of rolled 
paper, for forming small rolls of toilet paper or kitchen rolls 
(general-purpose towels) and other items. The device must be able to be 
adapted to various diameters of the material being processed. One object 
of the invention is to provide a clamp which is rapidly adjustable. A 
further object is to obtain economical adjustment without the replacement 
of components. These and other objects and advantages will be clearly 
understood from a reading of the text below. 
The clamp device according to the invention substantially comprises, for 
each path of advance of the rolls or logs and on each side of the cutting 
plane: 
a pair of symmetrically curved elastically flexible strips, projecting from 
enclosing supports, and having end portions able to move according to the 
variation in the diameters and having an elastic tendency to expand; and 
a strap fixed to elastic return and adjusting holders, and surrounding the 
pair of strips so as to vary their geometry in relation to the variation 
in the diameter of the material being processed. In the context of the 
present invention the term "strap" is to be understood in a broad sense. 
It may consist, in particular, of piano-wire tape or other material 
suitable for this purpose. 
In practice, the movable ends of the strips may be overlapped and slide 
over each other. The strap may act in combination with the strips to form 
the sliding path of the log in movement, and surrounds said path over 
approximately half a circumference; two opposing oscillating cradles, 
which adapt to the strips in the various geometries which they may assume, 
are provided adjacent to the enclosing supports. At least one of the two 
oscillating cradles, which is subject to the force of the disk-shaped 
blade, may be locked in the angular position assumed as a result of the 
adjustment according to the diameter of the material being processed. 
The strap may be held by an elastically prestressed holder. An adjustment 
system--of the jack or other type--is provided for the adjustment of the 
geometry of the straps according to the diameter of the material being 
processed. 
A single jack may act on the two adjacent straps of a cutter with two 
tracks for advancing and cutting adjacent rolls. A single jack may also 
act on the straps of one or two pairs of strips acting on the material on 
both sides of the cutting plane. 
Stops acting on the strips to prevent dragging the strips due to friction 
with the advancing material may advantageously be provided. Said stops may 
be formed by the edges of the strap, with the inner strip supported on the 
outer strip, or be external components which are adjustable according to 
the geometry assumed at different times by the strips. 
To lock two oscillating cradles, these may have an extension which 
continues as far as a corresponding joint engaging with a plate which is 
movable in a plane orthogonal to the axes of oscillation of the cradles 
and may be locked with a brake shoe in the geometry assumed on each 
occasion after adjustment. 
In a possible embodiment, the possibility of locking both oscillating 
cradles may be provided. For this purpose, they may both be coupled to 
extensions which interact with means of adjusting and locking, for example 
with threaded rod means. 
The clamp described here may advantageously be applied to cutting machines 
such as those described in Italian Patent Application No. FI91A 000071 and 
to all machines in which an opening and closing movement of the clamps for 
each cutting operation is not required. 
Further advantageous characteristics of the invention are indicated in the 
attached claims.

According to the illustrations in the attached drawing (with reference 
initially to FIGS. 1 to 7), 1 indicates a support structure of the clamp 
device, which is developed in the cutting plane and whose path is 
indicated by T in FIG. 2. On either side of this path are the clamps which 
act on the cylindrical material advanced in the direction of the arrow FM 
under the action of pushing extensions 3 which are carried by 
schematically indicated chain conveyers 5; these conveyers 5 have a 
continuous chain and act on the ends of the rolls or logs indicated 
overall by B, one end of which, shown in FIG. 2, is pushed by one of the 
extensions of the pushers 3. In the cutting plane with the path T--T, a 
circular blade rotating about its own axis and movable about another axis 
(which may be nearer or farther away) causes the rolls or logs to be cut 
into a number of small rolls which are then sent for packaging for 
distribution. Next to the cutting plane with the path T--T, the material 
being processed must be pressed by elements which bind it and keep it 
compressed and positioned with respect to the pushers to ensure the 
precision of the spacing between the cuts, in such a way as to ensure 
uniformity of cutting in said material. These pressing elements (clamps) 
must be able to be adapted easily to the different diameters of the 
material in rolls or logs B which are processed from time to time. FIGS. 
3, 4 and 5 indicate three different diameters of the rolls or logs. The 
advancing material, which is guided in suitable sliding cradles, must 
therefore pass through these elements of the retaining and pressing 
device, or clamps as they are called, both before reaching the cutting 
plane and after the cutting plane with respect to the direction of the 
arrow FM. Normally, the cutters have at least two sliding cradles to 
process simultaneously and with the same cutting blade two rows of rolls 
advancing in the corresponding cradles and with corresponding pushers 3 
and 5, as shown in the drawing. In a solution of this kind, four clamps, 
in other words four pressure retaining devices, are obviously provided, 
one pair acting on the same piece of material being processed, one before 
and one after the cutting plane with the path T--T in FIG. 2. 
The clamps concerned will now be described. 
7 indicates pairs of external supports and 9 indicates intermediate 
supports, which have, next to the vertical longitudinal plane of symmetry 
of each sliding area of a roll or log, surfaces 7A and 9A respectively 
which, with the aid of plates 10, form corresponding enclosing holders for 
the ends 12A, 14A of pairs of flexible strips 12 and 14 which also have an 
elastic tendency to expand and are shaped in a substantially symmetrical 
way to form in combination a housing through which the advancing roll or 
log B passes, the pressure on the material to be cut being exerted by said 
strips. The holders formed by the components 7, 10 and 9, 10 are spaced a 
short distance apart to permit the passage of the extensions 3 of the 
pushers engaged in the chain 5. 
The opposing supports 7 and 9 are pivoted at 16 on shaped blocks 18 which 
form oscillating cradles capable of forming a support for the strips 12 
and 14 in the extension of the lower part of the slide path which said 
strips 12 and 14 form for the sliding of the material. The oscillating 
cradles 18 may have different angular geometries according to the diameter 
of the material being processed, as may be seen by comparing FIGS. 3, 4 
and 5, which show the geometry for the largest, medium and smallest 
diametric section of the advancing material; the oscillating cradles 18 
are capable of assuming symmetrical positions with respect to the 
longitudinal and vertical plane of symmetry of the advancing material, 
under the action of the means described below which act on the pairs of 
strips 12, 14. 
The angular position which is spontaneously assumed and is symmetrical for 
the two oscillating cradles interacting with the same pair of strips 12 
and 14 is fixed in the way described below. 
To adjust and modify the geometry of the pairs of strips 12 and 14 of each 
clamp, and to exert the force, in other words the pressure, radially on 
the material being processed, it is provided that the upper part of the 
strips 12 and 14, which are more or less partially overlapped, is 
surrounded by a strap 22. This strap is fixed at one end to a holder 24A 
on a pneumatic spring 24 (collectively called an elastic holder) which 
acts on the outer part of the pair of adjacent damp straps 22, as seen in 
FIG. 1 in particular; this holder thus ensures that the strap can yield in 
the case of dimensional anomalies of the material. The inner parts of the 
two straps 22 are fixed to a double holder 26A of a jack 26 (collectively 
called an adjusting holder), which may normally be a mechanical jack 
capable of sliding vertically in such a way as to vary in the upper curve 
the geometry of the two straps 22 surrounding the pairs of strips 12, 14 
of the two clamps. When, as shown in FIG. 2, clamps contiguous on either 
side to the cutting plane are provided at the positions of each of the two 
slide paths for two rolls processed simultaneously, two adjacent 
mechanical jacks 26 may be provided as shown in FIG. 2, or a single 
mechanical jack 26 may be provided in which case there are four holders 
26A (instead of two) for the four straps 22 surrounding the four pairs of 
strips 12, 14. The straps 22 skim the blocks forming the shaped cradles 18 
oscillating about the axes defined by the pins 16. By varying the position 
of the holders 26A of the jack or jacks 26, a greater or lesser elastic 
expansion of the strips 12 and 14 may be obtained; in other words, a 
greater or lesser overlap of the free ends of said strips 12, 14 may be 
provided in the upper area of the space delimited by said pairs of strips 
12 and 14. The above may easily be deduced from a comparison between FIGS. 
3, 4 and 5, which show three of a multiplicity of geometries which are 
also continuously adjustable. By operating the jack or jacks 26, and by 
suitable adjustments which may be provided for the exact adaptation of the 
end holders of the straps, it is possible to provide one or other of the 
geometries capable of being assumed by the pairs of strips 12 and 14, to 
adapt them to the diameters of the materials being processed and to the 
amount of pressure with which said strips are to act on the material 
radially and centripetally. The geometry is set by the holders 26, and the 
elastic pressure is set by the pneumatic springs 24 of the piston and 
cylinder or equivalent type, whose operation may easily be adjusted and 
modified in a substantially uniform manner by controlling the supply 
pressure of the pneumatic springs 24 of the assembly. 
The oscillating cradles 18 may be locked in the position which they have 
reached for the adaptation to the diameters of the material being 
processed. For this purpose it may be provided that at least one of the 
two cradles 18--that subject to the force of the blade in the direction 
FL--of each pair interacting with a pair of strips 12, 14 is fitted with 
an extension 28 embedded in the block of the cradle and pivoted at its end 
at 30 on a plate 32, which may be displaced in a vertical plane orthogonal 
to the axes of the advancing materials and which moves in apertures 36 of 
the frame 1. As a result of the orientation of the cradles 18 and 
consequently of the extensions 28, the plate 32 assumes different 
positions according to the angular geometry assumed by said cradles. After 
this geometry of the cradles 18 about the pivots 16 has been reached, and 
consequently after the corresponding position has been reached by the 
plate 32, the latter is locked with tension jaw means 38 which fix the 
position of the plate 32 and consequently the position of the cradles 18. 
The strips 12 and 14 may be made of suitable elastic materials, in 
particular steel or polycarbonate or similar materials. The edge facing 
the material entering in the direction of the arrow FM is flared as shown 
at 12C in FIG. 2, as far as the strip 12 of the pair of strips 12 and 14 
is concerned. 
The inner surface of the strips 12 and 14 may be sufficiently ground or in 
any case treated so as to have minimum friction with the material 
advancing in the direction of the arrow FM, as a result of which the 
strips 12 and 14 may be only minimally subject to a dragging effect in the 
direction of the arrow FM by the material advancing for processing. 
Moreover, the possibility of providing suitable means, particularly dogs, 
which act on the strips 12 and 14 to prevent them from being dragged and 
consequently bent in the direction of advance of the material shown by the 
arrow FM, is not excluded. One of the solutions--which is visible in 
detail in FIG. 7--may provide for the formation of a dog, in other words a 
stop 12X on the strips such as 12, to interact with the corresponding 
edges of the strap 22, this being particularly secure for the size and for 
the type of fixing of said strap. Another arrangement, as indicated in 
FIG. 7, is to form a stop, in other words a dog, as indicated by 40, to 
act on an edge or abutment 12Y of the flared profile 12A of the strips 
such as 12 and 14, or also to act on the opposite edge of the strips 12 
and 14, particularly in the area of overlap of said strips, in other words 
in the area of the upper curve of the sliding space of the material in 
roll or log form; the dogs, in other words stops, such as 40 or that which 
may act on the opposite edges of the strips, will be adjustable according 
to the geometry assumed by the strips so that they can be adapted to the 
diameter of the material. The dog formed by the stop 12X acting on the 
strap 22 as shown in FIG. 7 is clearly adapted automatically by the 
movement and mutual guiding of the strips and of the strap. 
With the arrangement described it is possible to modify the geometry of the 
clamps rapidly, to adapt this geometry to the dimensions of the material 
processed at any time, while maintaining the correct operation of the 
clamps with uniform distribution of the pressure over the whole periphery 
of the material being processed, and with the possibility of even very 
fine adjustments of the elastic pressure action of the different clamps 
through the adaptations of the pneumatic springs and the adjustments of 
the holders or the fixing elements of the holders by the return effect 
provided by the jacks such as 26 or also by the holders such as 24A of the 
pneumatic springs 24. 
FIGS. 8 and 9 show, in a front and side view, a somewhat modified 
embodiment of the device according to the invention. 101 again indicates 
the supporting structure of the clamp device, and T in FIG. 9 indicates 
the path of the cutting plane. 103 indicates the pushing extensions or 
pushers for advancing the logs. 107 and 109 indicate outer and 
intermediate supports respectively, corresponding to the supports 7 and 9 
of the example of embodiment illustrated in FIGS. 1 to 6. Flexible strips 
112 and 114, corresponding to the strips 12 and 14 in the preceding 
example, are fixed to the supports 107 and 109 respectively. 
Shaped blocks 118, corresponding to the blocks 18, are pivoted at 116 on 
the supports 107 and 109, and form oscillating cradles capable of 
providing a support for the strips 114 and 112 in their lower part. As 
described above with reference to the oscillating cradles 18, the 
oscillating cradles 118 may also assume various angular geometries 
according to the diameters of the logs to be cut, by rotating about the 
pivot axis 116. 
A corresponding strap 122 passes over each pair of strips 112, 114. Each 
strap 122 is fixed at one of its ends to a holder 124A of a cylinder and 
piston actuator 124 which acts as a pneumatic spring. The opposite end of 
each strap 122 is coupled to a double holder 126A coupled to a threaded 
rod 126B capable of being raised and lowered by means of a handwheel drive 
127 or by an electric drive. As seen in particular in the side view in 
FIG. 9, a single handwheel 127 operates two threaded bars 126B, between 
which is provided a chain transmission 125. 
The function of the straps 122, of the pneumatic springs 124 and of the 
fixing system 126 corresponds to that of the similar elements illustrated 
in the example shown in FIGS. 1 to 6 and is therefore not described in 
greater detail. 
Each block or oscillating cradle 118 is integral with an extension or rod 
128 whose lower end is pivoted at 129 on a threaded bush 130 interacting 
with a threaded bar 132. As shown in particular in FIG. 8, the threaded 
bushes 130 of the rods 118 associated with the two oscillating cradles 118 
of each sliding path of the log are threaded onto two adjacent sections 
132A and 132B of the same threaded bar 132. The two sections 132A and 132B 
differ in the direction of the threading, so that a rotation in one 
direction of the threaded bar 132 causes symmetrical movements in opposite 
directions of the threaded bushes 130 associated with the rods 128 of two 
oscillating cradles 118 of the same sliding path of the log. 
A single handwheel 134 may be used to rotate, through a chain transmission 
136, two parallel threaded bars 132 to simultaneously cause the sliding of 
all the bushes 130 and consequently the simultaneous oscillation of all 
the oscillating cradles 118 associated with the eight elastic strips 112 
and 114 provided in the device shown in FIGS. 8 and 9. 
FIG. 8 shows the two end positions which the oscillating cradles 118 may 
have: in the left-hand sliding lane in the figure, the oscillating cradles 
118 are in their maximum opening position, corresponding to the maximum 
log diameter which can be processed with the device. In the right-hand 
sliding lane in FIG. 8, the oscillating cradles 118 are shown in their 
position corresponding to the minimum log diameter which can be processed. 
With the arrangement described here it is possible to simultaneously adjust 
the position of the oscillating cradles 118 with respect to the two strips 
112, 114 and that of each pressure group and to lock both said cradles. 
A special arrangement (which may also be adopted in the embodiment in the 
preceding figures) to enable each strap 122 to be guided correctly is 
shown in the embodiment in FIGS. 8 and 9. For this purpose, a plate 150 is 
fixed to each block or oscillating cradle 118. The plate 150 forms, 
together with the surface of the associated block 118 to which it is 
attached, a slide and guide path for the corresponding strap 122. In this 
way the strap 122 always takes up a correct position even in the 
processing of the minimum diameter (see the right-hand side of FIG. 8). 
In the embodiments described up to this point, the strips 12, 14 and 112, 
114 extend for a length such that their ends overlap above the log. The 
amount of overlap is a function of the diameter of the log being 
processed. However, the possibility of operating with shorter strips, 
which therefore do not overlap each other (at least for certain diameters 
of the log) is not excluded. This case is shown schematically in FIGS. 10 
and 11, where the strips are indicated by 112A and 114A. As seen in 
particular in FIG. 10, the extension of said strips is such as to leave 
free a portion of the cylindrical surface of the log passing through. This 
upper area of the log is clasped by the strap 122A. To ensure a proper 
grip, in this case the strap 122A may have an intermediate portion of 
width equal to the longitudinal extension of the strips 112A and 114A, in 
other words a width equal to the dimension d indicated in FIG. 11, with a 
flared profile 122C. This portion of the strap 122A is located in the 
upper clasping area of the log. The parts of the strap 122A extending 
downward have a smaller width d', equal for example to that of the strap 
122 in FIGS. 8 and 9. This configuration of the elastic strips 112 and 114 
and of the strap 122 may also be adopted in the embodiment in FIGS. 1 to 
6. 
It is to be understood that the drawing shows only an example provided 
solely as a practical demonstration of the invention, it being possible to 
vary this invention in its forms and arrangements without thereby 
departing from the scope of the guiding concept of said invention. 
Any presence of reference numbers in the attached claims has the object of 
facilitating the reading of the claims with reference to the description 
and to the drawing, and does not restrict the scope of protection 
represented by the claims.