Pinch cutting method and apparatus

An apparatus for cutting lengths of material is provided having a pair of scroll type cams adapted to operate a pair of laterally opposed cutting blades. The apparatus comprises a frame having a front end, a rear end, and generally parallel side members laterally opposed to each other and spaced apart by a plurality of rollers extending generally perpendicular between the parallel side members of the frame. The pair of laterally opposed cutting blades are pivotally connected to the front end of the frame. The blades are constructed from a metallic material, the surfaces of which may be heated electrically to facilitate cutting. The scroll type cams are rotatably mounted to each side of the frame near the ends of the cutting blades and are adapted to engage cam followers connected to the blades. Pneumatically operated cylinders simultaneously rotate each of the scroll cams in the same direction with respect to the frame to convert rotational motion of the cams to linear motion of the cam followers. Rotational movement of the scroll cams together in counterclockwise and clockwise directions is thereby translated into linear movement of the cutting blades toward and away from each other, respectively.

FIELD OF THE INVENTION 
The present invention relates generally to machinery for cutting sheets of 
material, and more particularly to a scroll operated apparatus and method 
for cutting lengths of tire building material to form pieces having ends 
which can be easily spliced together. 
BACKGROUND OF THE INVENTION 
Certain manufacturing processes require the attachment of overlapping ends 
of a precise length of material together to form a continuous loop of the 
material. Often, the precise length is cut from a continuous supply of the 
material. Heat treatment, or curing, is typically utilized to fuse the 
attached overlapping ends of the length of material together to increase 
the strength of the joint. 
An example of such a manufacturing process is tire building, wherein a 
precise length of rubber or other material is wrapped around a mandrel or 
drum to form part of the tire. The length of rubber or other material is 
cut so that the ends of the length overlap to form a splice. The 
overlapping ends are temporarily attached together to form a loop of 
material which is then cured to strengthen the rubber. 
The presence of a splice in the continuous loop of rubber or other material 
presents several problems. First, the double thickness of the spliced 
joint in the continuous loop of rubber or other material upsets the 
rotational balance of the tire formed therefrom. In addition, air is 
likely to be captured between the two overlapping ends of material, 
thereby weakening the resulting splice. Moreover, the entire material loop 
must be cured for the length of time required to cure the spliced joint of 
double thickness. 
By reducing the length and the thickness of the splice, the rotational 
balance of the tire is improved. The area between the overlapping ends of 
rubber or other material is reduced, thereby minimizing the amount of air 
which can be captured therebetween to weaken the resulting joint. In 
addition, curing time for the continuous loop is reduced, permitting 
greater throughput by the associated curing equipment. 
Devices for cutting sheets of material to be spliced together are known. 
For example, U.S. Pat. No. 4,426,901 to Hogan et al. discloses a cutter 
having heated, eccentrically mounted rollers which coact with each other 
to partially sever predetermined lengths of material from a continuous 
roll of the material. Retraction of a transport member, which works in 
conjunction with the eccentrically mounted rollers, completes the severing 
of the material. Material sheets having tapered ends are thereby provided 
using a two step process. 
Thus, advantages exist for reducing the length and the thickness of spliced 
joints formed in materials used to manufacture tires. The present 
invention provides a simplified apparatus and method for affording these 
advantages, while providing a high degree of flexibility in design and 
operation. 
SUMMARY OF THE INVENTION 
According to the present invention, an apparatus and method are provided 
for cutting accurate lengths of rubber or other material from a continuous 
supply of the material. The apparatus is relatively compact in size, and 
may be attached to existing servicers which dispense the material from the 
continuous supply to an operator or to the next processing step. 
The pinch cutting apparatus of the present invention includes a pair of 
scroll type cams adapted to operate a pair of cutting blades. The pair of 
cutting blades are pivotally mounted to a substantially rigid frame which 
is attachable to an existing servicer. A series of rollers span the frame 
for transporting the material to be cut from the servicer to the blades. 
Means for urging the pair of cutting blades into contact with and away 
from each other are also provided, comprising a pair of pneumatically 
operated scrolls rotatably mounted to the frame, and cam followers mounted 
to each of the pair of pivoting blades which are adapted to engage the 
scrolls. 
Extending from each side of a back end of the frame are cylindrical 
mounting posts, at which posts the pinch cutting apparatus may be 
pivotally attached to a servicer. Extending from each side of a front end 
of the frame are a pair of adjustable mounting arms. The adjustable 
mounting arms provide support for the end of the frame from which they 
extend, as well as means to adjust the position of the pinch cutting 
apparatus with respect to the servicer to which it is attached. 
The series of rollers which span the rigid frame are arranged in a 
generally planar pattern and are adapted to transport material from the 
servicer to the blades on the pinch cutting apparatus. A pair of guide 
rails extending upwardly from the frame are used to center the material on 
the series of rollers. A manual cable assembly provides means for 
adjusting the distance between the guide rails to accommodate various 
widths of material to be cut. 
The pair of cutting blades are electrically heated to assist in cutting 
through the rubber or other material passing over the series of rollers. 
Each of the blades is attached to a pinch beam which is in turn mounted to 
a pivot arm. Each of the pivot arms is mounted to the frame of the pinch 
cutting apparatus at a common pivot point. The common pivot point ensures 
that the two cutting blades are aligned with each other during the cutting 
process. By pivoting the pivot arms about this point toward the back end 
of the frame, the pinch beams and the attached cutting blades move from a 
position generally perpendicular to the plane of the series of rollers to 
a position generally parallel to the rollers. The pivot arms are pivoted 
about the common pivot point by means of a pneumatic cylinder. A linkage 
arrangement is attached at one end to the piston in the cylinder and at 
the other end to each of the pivot arms. 
When the piston attached to the linkage arrangement is extended, the pinch 
beams are positioned generally perpendicular to the series of rollers. In 
this position, the attached cutting blades face each other but remain 
separated by a distance sufficient to permit a length of rubber or other 
material to pass therethrough. The cutting blades are brought into contact 
with each other to cut through the material by rotating the scrolls. 
Rotation of the scrolls is controlled by a pair of pneumatic cylinders 
located on opposite sides of the frame. 
The scrolls are adapted to convert the relatively small rotational force 
provided by the pair of pneumatic cylinders to the relatively large linear 
force required by the cutting blades to sever the rubber or other 
material. The scrolls transmit this linear force to the blades by means of 
cam followers, which are fixedly attached to the pinch beams and are 
adapted to engage the scrolls. Upon rotation of the scrolls, the cam 
followers are forced toward each other. The electrically heated cutting 
blades are thereby forced through the material to be cut and into contact 
with each other. By reversing the rotation of the scrolls, the cam 
followers, and hence the cutting blades, are forced away from each other. 
The pinch beam support members may then be pivoted toward the back end of 
the frame so that the pinch beams are positioned parallel to the series of 
rollers. The pinch beams in this position provide greater clearance near 
the cutting area for maneuvering the next length of rubber or other 
material into position for cutting.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
A pinch cutting apparatus constructed according to the principles of the 
present invention is shown in FIGS. 1A and 1B generally at 10. The pinch 
cutting apparatus 10 is built around a substantially rigid frame 12 which 
comprises a pair of laterally opposed side members 14 and 16, each of 
which is preferably a steel beam. The ends of the laterally opposed side 
members 14 and 16 define a rear end 18 of the frame at which the apparatus 
may be attached to an existing servicer for dispensing material to be cut, 
and a front end 20 of the frame opposite the rear end 18. Pivotally 
connected with the front end 20 of the frame are a pair of cutting blades 
22. The cutting blades are urged into contact with and drawn away from 
each other by the rotation of a pair of scrolls 24 which are rotatably 
mounted to the front end of the frame and which engage cam followers 26 
operably connected to the cutting blades 22 (see FIGS. 2A, 2B). The side 
members 14 and 16 are supported and maintained in a spaced apart 
relationship by a rear mounting shaft 28, a central support beam 29 and a 
series of rollers 30. The mounting shaft 28 is preferably a solid steel 
shaft which connects the side members to each other near the rear end 18 
of the frame. The ends of the mounting shaft 28 extend beyond the side 
rails to provide extensions 32 and 34 at which the pinch cutting apparatus 
may be attached to the material dispensing servicer. The central support 
beam spans the side members and is also preferably made from steel. 
The side members 14 and 16 are additionally supported and maintained in a 
spaced apart relationship by the series of rollers 30 which span the 
distance separating the side members. The series of rollers 30 facilitate 
transfer of the material to be cut from the existing servicer attached to 
the rear end 18 of the frame to the cutting blades located at the front 
end 20 of the frame. Each of the rollers comprises a cylindrical sleeve 36 
surrounding a roller shaft 38. Suitable bearing means 40 may be utilized 
intermediate the roller sleeve and shaft. The rollers may be connected to 
the side rails by conventional means such as a threaded shaft and a nut 
screwed thereon. 
The pinch cutting apparatus is mounted to the existing servicer at the 
front end 20 of the frame by means of a pair of adjustable hangers 42 
located on either side of the frame. Each adjustable hanger comprises a 
front member 44 and a rear member 46 having threaded ends which are 
connected by a threaded sleeve 48. Rotation of the threaded sleeve adjusts 
the distance between the front and rear members of the hanger. The end of 
the rear member 46 opposite the threaded end may be connected to the 
servicer by means of a bolt 50 and a nut 52. The front member 44 is 
provided with a double eyelet 54 opposite the threaded end. The double 
eyelet is attached to a front frame extension 56 extending perpendicularly 
from the frame side members by means of a pin 58. The adjustable hangers 
42 thereby provide means for attaching the pinch cutting apparatus to a 
variety of servicer mounting arrangements. 
The pinch cutting apparatus is also provided with means to accommodate a 
variety of widths of material to be cut. Left and right guide rails 60 and 
62, respectively, are adapted to guide the material down the center of the 
series of rollers 30. The distance between the guide rails is adjustable 
by means of a manually operated guide adjust mechanism 64 which moves each 
of the guide rails equal distances when operated. Although a manual 
cable-operated mechanism is shown in FIGS. 1A and 1B, it is contemplated 
that any suitable guide adjust mechanism, either manual or automatic, may 
be used with the apparatus 10. 
The guide adjust mechanism comprises a pair of parallel shafts 66 extending 
between the side rails and mounted thereto by bolts 67, a pair of primary 
sleeves 68 which are connected with the guide rails and slide along the 
shafts 66, and a plate 70 which is pivotally mounted to the central 
support beam 29. The plate 70 is provided with slotted arms 72 which are 
adapted to engage portions of the primary sleeves 68, and a cable mount 74 
to which cable 76 is attached. Movement of the cable 76 pivots the plate 
70 which in turn forces the primary sleeves 68 inwardly toward each other 
or outwardly away from each other. The primary sleeves 68 are connected 
with the guide rails 60, 62 by means of a pair of metal bars 78 and a pair 
of secondary sleeves 80 which insure parallel movement of the side rails 
with respect to each other. Thus, movement of the cable 76 is translated 
into equivalent movement of the guide rails toward and away from each 
other. The primary and secondary sleeves 68 and 80, and the pair of metal 
bars 78, are attached to the side rails by common fasteners such as screws 
82. 
The mechanism for cutting the sheets of material transported along the 
series of rollers comprises the pair of pivotally mounted cutting blades 
22 and the pair of pneumatically operated scrolls 24. The cutting blades 
are adapted to move from a position parallel to the plane containing the 
series of rollers when not in use to a position perpendicular to the plane 
when in operation. The pneumatically operated scrolls engage the cutting 
blades when in this perpendicular position to force the blades into 
contact with each other to sever the material. 
The relationship between the scrolls 24 and the blades 22 is better 
illustrated in FIGS. 2A and 2B. Each of the pair of scrolls 24 is 
rotatably mounted near its center on a side of the frame at a center post 
84. The scrolls are preferably constructed from hardened steel plates 
having a groove pattern therein which spirals outwardly from the center. 
Cam followers 26 connected with the cutting blades 22 are adapted to 
engage the groove pattern in the scrolls to permit the blades to move 
relative to each other when the scrolls are rotated. 
The means to rotate the scrolls 24 are provided by a pair of pneumatic 
cylinders 88, one of which is associated with each scroll. Although 
pneumatic cylinders are shown, the invention contemplates other means for 
imparting rotational movement to the scrolls, including but not limited 
to, hydraulic cylinders or gear assemblies. One end of each cylinder is 
pivotally attached to a rear frame extension 90 extending outwardly from 
the frame 12. A piston 92 extendable from the other end of each cylinder 
is pivotally attached to each scroll at a mounting point 94. As shown in 
FIGS. 2A and 2B, the scroll is rotated fully clockwise, piston 92 is in a 
retracted position, and the cutting blades (not shown) are spaced apart 
about one eighth of an inch. Such a distance is sufficient for cutting a 
variety of materials including rubber tire interliner, which typically has 
a thickness range of about 0.050 inch to about 0.070 inch. 
When the cylinders 88 are connected to a source of pressurized supply air, 
the piston is extendable to rotate the scrolls in a counterclockwise 
motion as viewed from the sides of the apparatus. In the preferred 
embodiment, the scrolls are rotated counterclockwise approximately 110 
degrees from the position shown in FIG. 2B, thereby engaging the cam 
followers 26. Due to the spiral shape of the grooves in each of the 
scrolls, the cam followers 26, and hence the cutting blades 22, are forced 
toward each other. Thus, the scrolls convert the relatively small 
rotational force applied thereto by the pneumatic cylinders 88 to a 
relatively large linear force which is transmitted to the cutting blades 
by means of the cam followers. In the preferred embodiment, the cutting 
blades moving through a distance of about one eighth of an inch develop a 
linear cutting force sufficient to cut through sheets of material passing 
between the blades. Because of this large cutting force, the apparatus is 
provided with a pair of palm safety switches 95. The safety switches 95 
may be incorporated into the system so that the pneumatic cylinders are 
inoperative unless both palm switches are depressed, thereby insuring that 
an operator's hands are not near the blades during the cutting process. 
The pair of cutting blades are forced away from each other after a 
particular cut has been made by retracting the pistons 92 of the pneumatic 
cylinders 88. Retraction of the pistons in turn rotates the scrolls 24 
clockwise, which again forces the cutting blades apart. The cutting blades 
may then be pivoted out of the way in order to provide more clearance for 
the next sheet of material to be cut. 
FIGS. 3A, 3B and 4 better illustrate the pivoting action of the cutting 
blades 22. Each of the cutting blades 22 is mounted at the end of a pinch 
beam 96. The pinch beams 96 are attached to a pair of pivot arms 98 which 
are pivotally mounted to a common pivot point 100 on the frame 12. A third 
pneumatic cylinder 102, having less output power capability than the pair 
of pneumatic cylinders 88 which operate the scrolls 24, is used to pivot 
the arms 98, and hence the blades 22, about point 100 on the frame. 
Although a pneumatic cylinder is shown, the invention contemplates other 
means for imparting pivotal movement to the blades, including but not 
limited to, hydraulic cylinders or gear assemblies. The pinch beams 96 can 
thus be pivoted from a position generally perpendicular to the series of 
rollers (as shown in FIGS. 3A, 3B) to a position generally parallel to the 
plane of the rollers (as shown in FIG. 4). 
The pneumatic cylinder 102 is attached to the rear frame extension 90 near 
the rear end of the frame, and is provided with a piston 104 having an 
extension 106 attached thereto. The piston extension 106 is connected with 
the pair of pivot arms 98 by means of a linkage arrangement 108. When the 
piston 104 is fully extended from the cylinder, the pinch beams 96 are 
perpendicular to the rollers and the cam followers 26 are in a position to 
engage the scrolls 24 (see FIGS. 2A, 2B). 
The piston 104 is adapted to be retracted until the linkage 108 abuts a 
frame mounted stop 110. In this position, the cam followers cannot engage 
the scrolls, and thus rotation of the scrolls will not affect the position 
of the blades. In order to proceed with the next cutting sequence, the 
piston 104 must again be extended so that the cam followers are in 
position to engage the scrolls. The pair of cylinders 88 can then be 
activated to extend the pistons 92 and thereby rotate the scrolls 24 
counterclockwise to force the blades into contact with each other. In the 
preferred embodiment of the present invention, the output of a 
programmable controller (not shown) may be utilized to control the 
sequential operation of cylinders 88 and 102. In such an embodiment, the 
palm operated safety switches 95 may be used as inputs to the controller 
to disable the operation of the cylinders if the switches are not 
depressed. 
The pair of cutting blades 22 are shown in better detail in FIGS. 5A and 
5B. The blades are preferably made of a metallic material and are 
electrically heated by cartridge heaters (not shown) which assist the 
blades in the cutting process. As shown in FIG. 5B, the lower blade has a 
flat cutting surface 112 while the upper blade has a gradually tapered 
cutting surface 114. In the preferred embodiment, the gradual taper is 
around ten degrees, as measured from the flat lower cutting surface when 
the blades are in alignment and contacting each other. The tapered upper 
blade results in finished lengths of material having tapered cut edges. 
Such tapered edges permit splicing of both ends of the material in a 
manner which significantly reduces overlap. 
Accordingly, a pinch cutting method and apparatus have been described in 
the preferred form. However, with the present disclosure in mind, it is 
understood that the present disclosure of the preferred embodiment is made 
only by way of example, and that various changes may be implemented 
without departing from the true spirit and scope of the invention as 
hereinafter claimed.