Progressive roll bender

A machine for bending tubular or rod stock into complex, compound shapes has three driven synchronized rollers together with a single shaping roller also synchronously driven. The shaping roller is mounted on an arm pivotally mounted about the shaft of the downstream one of the three rollers and its movements are precisely controlled and effected by a single hydraulic cylinder. The control valve for the valve is entirely operated by a signal supplied from a omputer which has been pre-programmed to effect the formation of the particular shape or shapes desired.

FIELD OF THE INVENTION 
This invention relates to machines capable of forming tubular or rod stock 
into a wide variety of circular, ellipsoiddal, spiral or generally square, 
rectangular, rhomboidal, or trapezoidal configurations. 
BACKGROUND OF THE INVENTION 
Machines for shaping, coiling, bending or otherwise forming tubular or 
rod-shaped materials into numerous configurations have been known for many 
years. Many machines of varying complexity are available for these 
purposes, many of which are fully automated and have relatively high 
production speeds. However, these machines are limited to making of one 
particular configuration unless the machine is reorganized, that is 
retooled, to make a different shape. The down time required by some of the 
machines is substantial, particularly if the adjustment in shape is 
significant, such as from a square to a triangle or from a spiral to a 
final product of hexagonal or triangular shape. Furthermore, the machines 
have had only very limited capacity within which the overall size of the 
finished product can be varied. Thus, many companies either had to have a 
number of the machines to satisfy a wide variety of customer requirements 
or they had to seriously limit the variety of shapes they were capable of 
manufacturing. In any case, the retooling and reprogramming of a machine 
from one particular product configuration to another often required 
substantial down time to complete the changeover. None of the machines has 
been capable of being rapidly adapted from one product shape to another. 
None of the machines has been capable of changing from one product shape 
to another and then been capable of returning to the original shape 
without substantial retooling procedures. Furthermore, no single machine 
has been capable of producing a wide variety of shapes and sizes. 
BRIEF DESCRIPTION OF THE INVENTION 
The invention provides a means by which complex shapes can be formed from 
rod or tubular stock with the changeover from one shape to another being 
accomplished without changing the tooling of the machine. The machine is 
capable of being shifted from making a small part to a large part without 
changing the tooling of the machine. The machine provides a means of 
gripping a rod or a tube and by means capable of micropositioning a 
forming roller, of controlling not only the overall configuration but also 
the amount, degree and direction of the bend applied to the stock. The 
particular pattern to which the stock is shaped can be varied and 
controlled simply by controlling the machine's operating intervals and the 
position of a single moveable element. Once the control of the moveable 
element has been programmed, the machine controls the positioning of the 
stock engaging element in such a way as to produce the shape, size and 
overall configuration which it has been instructed to create. The 
changeover from one configuration or one size to another is accomplished 
without any change in tooling, the change being accomplished by shifting 
the timing, direction and arc of arcuate movement of a single roller which 
bears against the stock being fed through a positive drive path. The down 
time of equipment for tool change and testing is substantially reduced or 
eliminated and, thus, the cost of manufacturing a wide variety of complex 
shapes is reduced to such a degree that such shapes are economically 
practical. 
The invention provides a machine which can be readily programmed to take 
maximum advantage of the physical characteristics of the particular stock 
to be formed on it. By providing positive support for the stock during the 
bending operation, the stock can be shaped without distortion of the 
stock's cross section and without harmful stressing of the metal.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, the numeral 10 identifies a tube or rod bender or 
shaper having a supporting platform 11 for the bending mechanism 12. The 
platform 11 is provided with a suitable support 13. The support 13 has a 
control cabinet 14 which is connected to controller 62 (FIG. 10) for 
controlling the operation of the bender. The operation of the entire 
equipment is governed by the information which has been provided to the 
computer 15 and provides the basic program for the entire operation. As 
will be explained and illustrated subsequently, this particular 
arrangement and selection of equipment is illustrative only because 
various other items of equipment and arrangements can be substituted 
within the framework of the invention. 
The platform 11 has a flat top surface 16 on which is mounted a roller 
assembly 20 which is the actual tube or rod gripping and forming 
mechanism. For the sake of simplicity, hereinater the stock which is 
shaped by the invention will be referred to as "tubular". However, it 
should be understood that the invention is not limited to shaping tubular 
stock because it also will shape rod or stock of other cross-sectional 
shapes such as square, so long as the shape of the stock is symmetrical 
about its centerline. It is also necessary that the peripheral groove in 
the rollers be shaped to properly seat and support the stock. 
The rollers of the roller assembly are arranged in pairs (FIG. 7). The 
roller pairs are arranged to provide a path 24, shown in broken lines in 
FIGS. 7 and 7A, between them. Roller 25 is mounted on the upper end of a 
shaft 26 which extends through the platform 11 and below the platform is 
connected a gear drive 27 to a hydraulically powered prime mover 28 (FIG. 
9). This roller is hereafter referred to as the "drive roller". Pivotally 
mounted about the shaft below the drive roller is one end of an arm 30. 
Also mounted on and driven by the shaft 26 is a spur drive gear 31. 
Mounted on the arm 30 is a second spur gear 32 meshed to the gear 31. The 
gear 32 is keyed to a forming roller 33, both of which are mounted for 
rotation about a shaft 34. Thus, the roller 33 is synchronizally driven 
with the roller 25. 
The roller 39 is mounted to an arm 35 (FIGS. 5 and 7A) through one end of 
which rotatably passes the shaft 37 for the roller 39. The outer end of 
the arm is secured to the platform by suitable means such as a stud bolt 
36 thus preventing any pivotal motion about the shaft 26. Secured to the 
fixed arm is a shaft 37 which mounts the spur gear 38 and its associated 
squeeze roller 39. The gear 38 and roller 39 are interconnected for 
simultaneous rotation by suitable means, such as a key, in the same manner 
as the gear 32 and roller 33. The gear 38 meshes with and is driven by the 
drive gear 31 but is always spaced from the forming roller 33. 
Pivotally mounted about the shaft 37 is one end of the clamp arm 43 which, 
in its release position, is substantially parallel to and extends in a 
direction opposite to that of the arm 30. The clamp arm mounts a shaft 44 
which in turn rotatably mounts the spur gear 45 and the clamp roller 46 
which is keyed to the gear 45. The gear 45 meshes with and is driven by 
the gear 38 and, thus, through the gear 38 is synchronously driven from 
the drive gear 31. 
The clamp arm has only a very limited arc of movement. This movement is 
such that, at its position of maximum movement away from the drive roller, 
a tube path 24 is created which is only slightly larger than that 
necessary to slidably receive the stock to be formed for the purpose of 
initially introducing the stock into the path 24. This position is made 
adjustable by the adjustable stop 47 (FIG. 7). During operation, the free 
end of the clamp arm 43 is pressed against the stop 47 by the toggle lock 
48. 
To provide a path for the stock 60 to be shaped, the rollers 25, 33, 39 and 
46 each have a peripheral groove or channel 50 (FIG. 2), the recess of 
which has a radius to seat closely about the stock. If the stock is of 
non-circular cross-section, the shape of this groove must be changed to 
accommodate this fact. However, the depth of the channel 50 is equal to or 
only slightly less than the radius of the external surface of the stock. 
Channels of this depth can be utilized because, along the tube path 24, 
the peripheries of the rollers are always spaced apart at least a little 
more than the diameter of the stock channels of the rollers. This 
arrangement permits the walls of the channels to provide positive support 
to and firmly grip the walls of the stock and thus apply sufficient 
frictional grip to positively drive the stock as it is being forced 
through the bending process. This is very important because any slippage 
between the stock and the rollers will result in an improperly shaped 
product. 
The arcuate position of the shaping roller 33 is the sole means by which 
stock is shaped. Its position is controlled by the hydraulic cylinder 54 
which is supported on the pivot 55 at its end adjacent the arm 30 (FIG. 
1). The hydraulic cylinder has a piston 56 the end of which is pivotally 
attached to the outer end of the arm 30. Movement of the piston is in 
response to the valve assembly 60 (FIG. 1) which controls the admission 
and release of hydraulic fluid to and from the cylinder 54. The valve 
assembly 60 is connected to a fluid port behind the piston of the valve 
assembly and to a fluid port at the front of the piston through the 
conduit 61. Operation of the valve 60 is governed by the controller 62 
through the line 63 and hydraulic fluid is supplied and exhausted through 
the hoses 64 and 64a. A valve controller 62 capable of operating this 
equipment is model LESA1-EDC 100 manufactured by Aeroquip Corporation, 
Jackson, Mich., which is illustrated only diagrammatically in FIG. 10 and 
is mounted in a pedestal separate from the platform. Connected to the 
valve controller 62 by the cable 18 is computer or programmable logic 
controller 15. A suitable unit for this purpose is the digital controller 
SLC 150 manufactured by Allen Bradley, Milwaukee, Wis. The computer 15 
controls only the operation of the gear drive 17 which is done through the 
cable 69. The lineal movement of the stock by the gear drive, that is 
degrees of rotation of the gears, is recorded by the encoder 65 in units 
of 12 seconds of arc comprising each unit through information furnished by 
means of the interconnecting shaft 19 from the gear drive 17. This 
information is provided to the controller 62 and to the computer 15 
through the line 28. 
The controller 62 is equipment having computer capability and performs the 
central function of coordinating the operations of both the computer 15 
and, thus of the gear drive, and also that of the valve 60. The operation 
of the valve 60 by the controller 62 is responsive to the information 
which has been programmed into the controller and the information provided 
to the controller by the encoder 65 concerning the operation of the gear 
drive 17 which controls the lineal movement of the work stock. Information 
concerning the amount and direction of movement of the piston 56 is 
provided by means 66 mounted within the cylinder 54 which magnetically 
reads incremental movements of the piston rod. Because the equipment must 
react rapidly and very accurately, the increments of movement which are 
read are small, such as 0.001 inch. For this purpose, a reader 66 
manufactured by Aeroquip TJ Corporation, Jackson, Mich. has proven to have 
the necessary degree of reliability and precision. The signals produced by 
the reader 66 are transmitted to the controller 62 through the cable 67. 
The valve 60 which controls the position of the piston 56 is of the two-way 
servo type. It is important to the function of the bending mechanism 12 
that this valve be of the rapid, micro-response type capable of 
coordinated, substantially instantaneous response, effecting very precise 
control of the flow of hydraulic fluid in either direction. This is 
essential to accuracy in shaping the stock. These valves must also be 
capable of rapid flow of a substantial quantity of hydraulic fluid when a 
major change in the shape of the stock is desired. An important 
characteristic of these valves is the speed of response to eliminate, as 
much as possible, the lapse time between receipt of a signal and 
completion of the response to the signal both as to volume of flow and the 
length of the interval of flow. 
To make any of the particular shapes illustrated in FIGS. 11-16 or others, 
the information necessary to coordinate the operations of the gear drive 
17 controlled by the computer 15 and of the piston 56 controlled by the 
valve 60 is programmed into the controller 62 which centralizes the 
operation of the entire equipment. 
OPERATION 
To prepare the bending mechanism to receive the stock 24, the piston 56 is 
fully retracted. Also the toggle lock 48 is released permitting the 
clamping roller 46 to shift counterclockwise so that the stock A can be 
passed between the clamping roller 46 and the squeeze roller 39 and be 
inclined to the axis 24 just enough to permit the end to be passed between 
the drive and shaping rollers 25 and 33. If there is resistance to the 
operation, the stock A can be fed between the drive roller 25 and the 
shaping roller 33 by operating the rollers at a low speed just sufficient 
that the end of the stock makes full contact with the peripheral grooves 
of these rollers. The toggle lock is then closed, pivoting the clamping 
roller 46 into a position which causes the stock to make firm, driving 
contact with the bottom and sides of the grooves of all of the rollers. 
The final position of the clamping roller can be precisely adjusted by 
extending or retracting the stop 47 and the end of the toggle lock 48. 
This arrangement also provides adjustment for stock of different sizes. 
Information concerning the particular shape to be produced is then or has 
previously been fed into the controller 62 and the computer 15 from a 
programming board. The controller 62, having been appropriately prepared 
to process the directions it receives from the program then manipulates 
the valve 60 to control the position of the forming roller 33. The 
controller 62 is also provided with information concerning the lineal 
speed of movement of the stock by the encoder 65. Preferably, this is a 
constant, but it is possible to make this variable with appropriate 
control of the speed of the hydraulic drive 28 or by use of a variable 
speed control means, not illustrated, between the prime mover and the 
shaft 26. Thus, once the controller 62 has been properly programmed, the 
operation of the bending mechanism is then thereafter totally controlled 
by the coordinated operations of the controller 62 and computer 15. In 
response to commands from the controller 62, the piston 56 is advanced or 
retracted by the valve 60. The computer 15 in coordination with the 
controller 62 and information from the encoder 65 through the line 69 
controls the operation of the gear drive 17. The controller 62 accuately 
controls the timing, direction and amount of the piston's actuation in 
precise coordination with the rate and direction of lineal movement of the 
stock. 
When the shaping roller 33 is in its initial or starting position, as 
illustrated in FIG. 2, the stock will pass through the machine without 
change. However, even a small increment of movement of the roller 33 to 
the right, as illustrated in FIG. 3, will initiate bending of the stock. 
The sharpness of the bend can be increased until the minimum inside radius 
is only a small amount greater than that of the root of the groove of the 
drive roller 25. The minimum radius of curvature is governed by the 
diameter of the stock, the metal from which the stock was made and the 
root diameter of the rollers with which the machine is equipped. 
By alternately advancing and retracting the shaping roller 33 a large 
variety of shapes can be created. By controlling the rate of advancement 
and retraction in coordination with the lineal spped at which the stock is 
fed through the equipment, the shape can be varied almost without limit. 
Thus, by maintaining the shaping roller 33 at a fixed degree of 
advancement, a coil 100 will be formed, the diameter of which is governed 
by the amount the roller has been advanced (FIG. 11). By sequentially 
advancing and retracting the shaping roller twice followed by the rollers 
being left in fully retracted position or a specific interval between each 
such sequence, an elongated loop 101 is created (FIG. 12). By use of the 
same procedure except by providing a period of identical duration between 
each advance and retraction operation of the roller 33, a square 102 can 
be formed (FIG. 13). By decreasing the length of the interval during which 
the roller 33 is being shifted from retracted position to fully advanced, 
the radius of the corner thus formed is controlled. Thus, the shorter the 
interval during which the roller 33 is in movement, the more abrupt the 
bend and thus the smaller the radius of the corners. Also by increasing 
the length of the interval during which the roller remains in a selected, 
advanced position, the greater the bend. Thus, by increasing the interval 
over that required to form a square, a triangular coil 103 can be formed 
(FIG. 14). By proper programming of the operation of the cylinder to 
manipulate the piston 56, a wide variety of complex shapes can be made, 
such as the ring 104 of FIG. 21 and the undulating shape 105 of FIG. 16. 
The machine can be so programmed that it will bend a single length of pipe 
and rod into several different shapes, such as a circular coil such as 
illustrated in FIG. 11 followed by a portion of the stock being formed 
into a square such as illustrated in FIG. 13. By programming the movement 
of the forming roller 33, even more complex shapes, such as prolate or 
oblate ellipzoids and polygons can be formed. 
The use of a single element to perform all of the bending functions 
eliminates the necessity for coordination between plural elements working 
in concert and reduces the problems of time and magnitude coordination and 
further of maintaining accuracy in the coordination. The use of a single 
mechanism to bend the work pieces greatly simplifies the equipment without 
reducing its versatility. While it is possible to provide means to vary 
the lineal speed at which the stock is moved along the path 24, this is 
not necessary if the stock being processed is always uniform. It might be 
desirable to vary the lineal speed of the stock when the invention is used 
to make shapes having long straight sections although it does add another 
factor complicating the control of accuracy. One of the important features 
of the invention is that the use of four rollers arranged in the 
particular configuration which has been described, using only one roller 
movable to effect the bending, makes precision much more readily 
controlled. This is essential to producing a final configuration to within 
tolerances not previously possible. Also, because the forming is done 
under circumstances in which the stock is positively and closely supported 
during the ending, the stock can be shaped into complicated configuration 
without distortion of the cross-sectional shape. This is very important to 
many applications for tubing. 
Providing the ablity to vary the lineal speed of the stock would be 
valuable and, in fact, could be essential in cases in which stock of 
metals of significantly different characteristics or of different wall 
thicknesses or when both rod and tube are to be formed on the same 
machine. Since to produce a shaped product without significant variation 
of its cross-sectional dimension, it is necessary to cause the metal to 
flow to account for the difference in arc length between the inside and 
outside walls of the stock. Further, this must be done while the stock is 
so held that it wll neither wrinkle along the inner radius of the bend nor 
lose its circular shape by distorting sideways nor stretch to the point of 
rupture along the outer radius. The ability of metal to have adequate flow 
to do this depends upon the degree of tension and compression to which it 
is subjected, together with the length of the time period required for the 
flow to occur as well as the characteristics of the metal itself. These 
can be accounted for to a significant degree by controlling the time lapse 
allowed for the flow to occur. The variation in time lapse has to be 
provided by varying the lineal speed of the stock. 
It is essential that the cylinder 56 be operated hydraulically because 
liquids are capable of more rapid and precise response to changes in 
pressure and flow rates than pneumatics because of their lack of 
compressibility. This is essential to provide the speed and accuracy of 
response which is basic to this invention. 
Having described a preferred embodiment of our invention, it will be 
recognized that various modifications of it can be made without departing 
from its principles. Such modifications are to be considered as included 
in the hereinafter appended claims unless these claims, by their language 
expressly state otherwise.