Ring former and cutoff

A ring former and cutoff utilizes a continuous ring former which causes the stock to assume the form of a helix having a number of turns. The leading end of the helix after forming a plurality of free turns passes through a drive roll set, through a stationary cutoff die and into a sizing hoop of larger diameter than those in the turns of the helix. The free end of the helix to expand within the sizing hoop. Sensors detect the expansion to energize the cutoff at the die to sever a turn of the helix with the momentary halt of the stock at the die causing the helix between the cutoff and former to expand or unwind. When the severed end of the helix is removed or falls free, the drive roll set again drives the new leading end of the helix through the cutoff die at a speed sufficient to return or wind the helix to its original condition.

DISCLOSURE 
This invention relates generally as indicated to a ring former and cutoff 
and more particularly to a high speed machine and method for the 
manufacture of rings. 
BACKGROUND OF THE INVENTION 
In the manufacture of rings of various types, strip stock is fed through a 
forming mill to impart to the ring stock the desired sectional shape. The 
stock then passes through a bender which then coils the stock into a ring 
or helix condition. In order to sever the stock of the desired size with 
any degree of accuracy, flying cutoffs are usually employed. 
Flying cutoffs are well known in the art and the dies thereof are 
accelerated to the speed of the work in order to make the cut. After the 
cut is made the dies are stopped and returned to the original position to 
make the next cut. Flying cutoffs require complex controls and also 
require a great amount of energy, particularly if the cutoff is of any 
size, to accelerate the dies, make the cut, stop the dies, and then return 
them to the original position. Moreover, when forming rings, the cutoff 
and die may require to travel in a circular path, further complicating the 
drives involved. 
With flying cutoffs the cycle of operation is normally lengthened to permit 
the acceleration, the cut, the stop, and return of the original position. 
Accordingly, flying cutoffs limit the productivity of the ring forming 
machine. 
SUMMARY OF THE INVENTION 
It has been found that a stationary cutoff can be employed in ring forming 
machines if the stock is formed into a helix and the turns of the helix 
between the cutoff and the ring former are permitted to expand and 
contract to compensate for the momentary delay in the travel of the stock 
which results from the use of a stationary cutoff die. 
Accordingly, the present invention provides a machine and method for 
forming rings which utilizes a continuous ring former which causes the 
stock to assume the form of a helix having a number of turns. The leading 
end of the helix after forming a plurality of free turns passes through a 
drive roll set, through a stationary cutoff die and into a sizing hoop of 
slightly larger diameter than the turns of the helix. The free end of the 
helix engages a stop with the drive roll set causing the free end of the 
helix which encompasses one complete circle to expand within the sizing 
hoop. The sizing hoop is provided with sensing means which detects the 
expansion of the turn of the helix therein to energize the cutoff to sever 
the free end of the helix with the momentary halt of the stock at the die 
causing the helix between the cutoff and the former to expand or unwind. 
When the severed end of the helix is removed or falls free, the drive roll 
set again drives the new leading end of the helix through the cutoff die 
at a speed sufficient to return or wind the helix to its original 
condition. The expansion and contraction of the helix is within the 
elastic limits of the stock formed and coiled. 
The sizing hoop may readily be removed and replaced with a hoop of 
different size so that different size rings may be formed. 
With the present invention, a lower cost machine having greater 
circumferential accuracy for the formation of the rings is achieved. 
It is accordingly a principal object of the present invention to provide a 
ring forming machine utilizing a stationary cutoff. 
Another principal object is the provision of a ring forming machine and 
method which coils the stock into the form of a helix with the turns of 
the helix between the cutoff and former expanding and contracting to 
compensate for the momentary halt of the stock during the cutoff. 
A further important object is the provision of a ring former and cutoff 
machine and method which utilizes a drive roll set in association with a 
stationary cutoff die which drives the free end of the stock through the 
die and into a sizing hoop. 
Another important object is the provision of a replaceable sizing hoop into 
which the free end of the helix is driven with expansion of the helix 
within the sizing hoop initiating the cutoff stroke. 
Another object is the provision of an expansion hoop in connection with a 
cutoff die wherein the size of the work within the hoop is detected to 
initiate the cutoff stroke. 
Yet another important object is the provision of a ring former and cutoff 
of low cost and maintenance. 
Still another important object is the provision of a ring former and cutoff 
having greatly increased productivity with less moving components. 
It is also an important object to provide a ring former and cutoff which 
can readily be converted to the manufacture of rings of different sizes. 
Other objects and advantages of the present invention will become apparent 
as the following description proceeds. 
To the accomplishment of the foregoing and related ends the invention, 
then, comprises the features hereinafter fully described and particularly 
pointed out in the claims, the following description and the annexed 
drawings setting forth in detail certain illustrative embodiments of the 
invention, these being indicative, however, of but a few of the various 
ways in which the principles of the invention may be employed.

DETAILED DESCRIPTION OF THE DRAWINGS 
Referring now to the drawings and more particularly to FIG. 1, there is 
illustrated a complete forming line for forming rings in accordance with 
the present invention. The illustrated line is for forming bicycle wheels 
rims but it will be appreciated that the present invention may be utilized 
for any hoop or ring type product such as barrel retainers, automobile 
wheel trim rings, or other type of ring products. 
The stock being formed may be, for example, a flat folded tubular element 
such as the aforenoted bicycle wheel rim which is seam welded. Strip stock 
S from the uncoiler 10 passes through a leveler 11 and into a punch press 
12 through a festoon or loop 13. The punch press 12 may place holes in the 
stock for a variety of purposes such as affixing spokes or creating drain 
holes for the interior of the flat folded tube. From the punch 12 the 
stock passes through a further loop or festoon 14 and into the forming 
mill 15. In the forming mill the stock is folded on itself and formed to 
the sectional configuration of a bicycle wheel rim. The stock then passes 
through seam welder 16 which welds the edges of the strip together forming 
the completed formed or flattened tubular configuration of the rim. 
From the welder the stock then passes through sizing roll sets 18 and 19 
into coil former 20. The coil former 20 includes main top and bottom pinch 
rolls 22 and 23, respectively projecting in cantilever fashion from 
housing 24. A somewhat smaller bending roll 25 is secured by adjustment 26 
to a bracket 27 which is in turn secured to the underside of projecting 
frame 28 mounted on top of the housing 24. The bending roll 25 is 
downstream of the nip of the rolls 22 and 23. Upstream of the nip are two 
screw-down reaction rolls 30 and 31 mounted on the plate 32 projecting 
from the housing 24. The rolls 30 and 31 keep the stock horizontal and 
from bowing upwardly or teetering at the nip of the rolls 22 and 23. A 
deflection plate extends at the edge of the path of the stock so that as 
the stock is bent beyond its elastic limit, it forms the initial turn 36 
of a helix shown generally at 37. 
As the helix is formed it extends axially of the bottom roll 23 and is 
supported on a rolling arbor 40 extending therefrom. The rolling arbor 40, 
like the helix 37 projects toward the viewer as seen in FIGS. 2, 3 and 4. 
The rolling arbor for the most part has a smooth exterior diameter. 
However, it is provided with slightly projecting end flange 42 and an 
inwardly spaced flange 43 forming a track therebetween. Such flanges serve 
as a locater for the helix turn passing over the top of the rolling arbor 
as seen at 44. 
Both the rolling arbor and the helix 37 extend axially from the former 20 
into the window 46 of frame 47 of cutoff 48. The frame 47 includes a base 
plate 50 which may be secured to the floor, and a vertically upwardly 
spaced base plate 51 forming the lower edge of the window 46. The plate 51 
extends between side plates 52 and 53. The side plate 52 is bent toward 
the side plate 53 as indicated at 54. The side plates are interconnected 
by a relatively thick top plate 55 which completes the opening 46. 
Stiffening flanges 56 may be provided on the side plates. 
Mounted on top of the top plate 55 is a pneumatic power press shown 
generally at 60 which includes a base plate 61 supported on spacer 62. 
Projecting upwardly from the base plate are two vertically extending rods 
63 and 64 to which are secured the top and bottom plates 65 and 66 of 
pneumatic piston-cylinder assembly 67. The piston-cylinder assembly may 
have a relatively large bore such as 20.32 cm. and short stroke such as 
2.54 cm. 
Projecting below the plate 55 is a stationary die frame 70 to the front 
lower end of which is secured a further die element 71. Both the die frame 
and die element are provided with a window seen at 72 in FIG. 2 through 
which the stock passes. A horizontally extending plate 74 on the bottom of 
the dies supports guide rolls 75 and 76 immediately upstream of the die 
opening window 72 to guide the stock into the window of the die. 
The rod 78 of the press is connected to a vertically extending plate 79 
which is gibbed for sliding movement on the face of the die frame 70 as 
indicated at 80 and 81. A cutoff blade 82 is secured to the lower end of 
the plate 79. When the pneumatic press extends, the blade 82 moves through 
the window 72 formed by the stationary dies severing the stock within the 
window. 
Immediately upstream of the guide rolls 75 and 76 is a drive roll set seen 
at 86. The drive roll set is seen more clearly in FIG. 4 and in detail in 
FIG. 5. The drive roll set is mounted on a pad 88 on the interior of the 
plate 53 and includes a vertically adjustable base plate 89. 
Projecting at a downwardly inclined angle from the base plate 89 are side 
plates 92 and 93. Journaled in the side plate 93 as indicated at 94 is the 
extension 95 of adapter roll hub 96. A top drive roll 97 is secured to the 
adapter hub 96 by the fasteners indicated at 98. An air motor 100 is 
mounted on the side plate 92 by the fasteners 101. The drive shaft 102 of 
the air motor is keyed to the interior of the hub 96 as indicated at 103. 
More closely spaced side plate extensions 105 and 106 are secured to the 
side plates 92 and 93, respectively. The side plate extensions are slotted 
at 107 and 108 to receive shaft 109 on which is journaled bottom roll 111. 
The projecting ends of the shaft 109 may be flattened to receive springs 
112 and 113 supported on spring guides 114 and 115, respectively. Each 
spring guide is mounted on an adjustment screw as seen at 116 and 117, 
respectively. The adjustment screws are threaded in the housing at 118 and 
119 and jam nuts seen at 120 and 121 secure the screws in adjusted 
position. It is noted that the rolls 97 and 111 are profiled to receive 
the stock S therebetween, and that only the roll 97 is driven by the air 
motor 100. The pressure of springs 112 and 113 holds the roll 111 against 
the stock S and in turn holds the stock S against the roll 97. 
It is noted that the air motor could as well be a variable speed electric 
motor or a hydraulic motor. In any event, the motor 100 is independent of 
the speed of the line seen in FIG. 1 within certain parameters as 
hereinafter discussed. 
Referring again to FIGS. 2, 3 and 4, it will be seen that the cutoff is 
provided with a sizing hoop shown generally at 130. The sizing hoop 
includes a right circular cylindrical band 131 which is not of uniform 
axial width. The front edge 132 of the sizing hoop seen in FIG. 2 is 
normal to its axis while the rear edge 133 is in the form of a helix. The 
beginning and end of the helix edge are interconnected by an axially 
extending edge immediately downstream of the die as seen at 135. 
Substantially adjacent the helical inside edge of the sizing hoop is a 
helical radially inwardly extending flange or guide plate 137. The guide 
plate 137 starts at 138 as seen in FIG. 4 just inside the stock opening in 
the die or away from the viewer in FIG. 4, and terminates at 139 outside 
the die, or toward the viewer. Immediately beyond the termination 139 of 
the guide plate 137 is a laterally projecting disappearing stop 140 
extending from the plate 79. 
Secured to the exterior of the sizing hoop are two angle brackets 144 and 
145. A connecting plate 146 extends between the angle bracket 144 and 
angle bracket 147 which is secured to the underside of the top plate 55. 
Similarly, a connecting plate 148 interconnects angle bracket 145 and 
angle bracket 149 secured to base plate 51. In this manner the sizing hoop 
130 may readily be removed and replaced with a sizing hoop of different 
diameter. 
The cylindrical wall 131 of the sizing hoop is provided with three 
substantially equally spaced windows through which project flat spring 
fingers 152, 153 and 154. Each spring finger is secured to the exterior of 
the hoop as seen at 155. 
Also secured to the exterior of the hoop are three microswitches seen at 
157, 158 and 159, each of which is adjustably mounted on brackets 160. The 
microswitches can quickly be very accurately adjusted to obtain precision 
of the circumference of the final turn of the helix encompassed within the 
hoop when cut. Each microswitch also includes a roller plunger 161 
projecting into the respective window in the hoop and adapted to be moved 
by contact by the respective spring finger. It is noted that the spring 
fingers project in a counterclockwise direction as viewed in FIG. 4, which 
is the direction of movement of the stock. 
Also, as seen in FIG. 4, a further switch 163 is provided which includes 
the plunger 164. The switch 163 detects the diameter of the turns of the 
helix 37 between the cutoff and the former and is used to control or 
periodically stop air motor 100 to allow the line speed of the entire line 
to catch up the cutoff. Also provided in the interior of the helix is a 
chip chute 166 designed to receive the small chips or severed sections of 
the stock which result from the cutoff and deflect them axially of the 
helix 37. 
Referring now to FIG. 6, it will be seen that the three microswitches 157, 
158 and 159 are in series with cut relay 170 and accordingly all three 
switches must be closed before the cutoff cycle starts. It is noted that 
each sensing switch also energizes a different colored warning light as 
seen at 172, 173 and 174, so the operator can quickly determine which 
switch is not working. 
When all three switches are closed, the relay 170 closes switch 176 
energizing solenoid 177 shifting directional valve 178. When the valve 178 
is shifted the rod 78 quickly extends to make the cut and at the extended 
position of the rod, limit switch 180 opens switch 181 to de-energize the 
relay 170 returning the directional valve to its original position causing 
the cutting blade to retract. 
OPERATION 
Strip stock from the uncoiler 10 passes through the punch 12 and the roll 
former 15 to be formed and then welded by the welder 16 to achieve 
substantially the configuration seen more clearly in FIG. 5. The stock 
then passes through the former 20 and is formed into the helix 37. The 
helix has a diameter somewhat smaller than the diameter of the sizing hoop 
130. The coiled rims now in the form of helix 37 are supported on the 
rolling arbor 40 leading to coils from the coiling device 20 to the cutoff 
48. In the illustrated embodiment, the number of free helixes or turns 
between the coiler and cutoff is seven. It is in these seven free turns of 
the helix 37 that the cutoff hesitation is absorbed during the severing 
cycle produced by the actuation of the piston-cylinder assembly 67. 
The leading edge of the helix is advanced through the track 44 on the 
outboard end of the rolling arbor and then through drive roll set 86 in 
the pressure nip between the rolls 97 and 111. The leading end then passes 
through the guide rolls 75 and 76 and into the open window of the 
stationary cutoff die. Just beyond the window the leading end of the stock 
is guided by the helix guide plate 137 to extend around the inside of the 
sizing hoop until it engages the stop 140. At this point the air motor 100 
is driving the final turn of the helix through the cutoff die and when the 
leading edge engages the stop the final turn of the helix begins to expand 
within the sizing hoop. The expansion of the final turn of the helix trips 
the switches 157, 158 and 159. When all such switches are tripped the 
relay 170 causes the blade 82 to extend making the cut. The cut, of 
course, momentarily stops the advance of the stock. The stop hesitates for 
approximately 15/8 inches (41.28 mm) of travel when the line is running at 
approximately 100 feet (30.5 meters) per minute. The 15/8 inches (41.28 
mm.) is divided at approximately 1/4 inch (6.35 mm.) per each of the seven 
turns of the helix 37. Thus, the helix between the former and cutoff 
expands slightly. During this cutting cycle the air motor 100 goes into a 
stall condition thereby stopping its propelling action. 
The stock which is coiled somewhat undersized advances in a 
counterclockwise direction as seen in FIG. 4 inside the confining or 
sizing hoop. As the end of the stock reaches the cutoff die knife line, it 
is now on the outside of the cutting aperture or window or toward the 
viewer in FIG. 2. This position is achieved by the helix guide plate 137. 
The air motor driven pinch rolls 97 and 111 continue to propel the coil 
swelling it into the sizing band. When the hoop is fully filled and tight, 
all three limit switches are closed and the cut is made. 
During the cut with the air motor 100 in a stall condition, thereby 
stopping the propelling action, the forming line continues to feed 
material and the accumulation is absorbed equally by the seven helix turns 
imparting only a minor swelling in each so that no permanent radius 
distortion results. 
The severed ring bypasses the disappearing stop 140 and contracts to its 
original diameter which now makes it loose within the sizing hoop. The 
finished part is ejected to the front or toward the viewer in FIG. 4 for 
subsequent manufacturing operations. It may simply fall onto a supporting 
bar 190 seen in FIG. 1 mounted on stand 191. The rings thus formed may be 
accumulated and subsequently removed for subsequent manufacturing 
operations such as butt welding. 
It is noted that the air motor 100 must feed the stock from the former or 
coiler at a speed somewhat faster than the output speed of the line. In 
this manner the air driven feed can catch up and deplete the accumulation 
that has occurred in the free helix turns during the cut. Although speed 
matching is not critical and may be done with a simple tachometer, it is 
noted that switch 163 insures that the air feed does not drive too fast 
causing the incoming helix turns to assume too small of a diameter. If 
they do, the switch 163 stops the drive periodically and permits the 
forming line to catch up. In this manner the line is in some respects 
self-synchronizing as long as the air speed is reasonably close to but 
slightly faster than the speed of the forming line. 
It will be appreciated that the cutoff element need not be air powered as 
in the illustrated embodiment. It may be a mechanical press, a saw or 
other conventional severing device. 
It will also be appreciated that the number of free turns of the helix 
between the former and cutoff is dependent upon the character of the work 
being processed. In any event, the expansion and contraction of the free 
turns of the helix between the former and cutoff is limited to the elastic 
limit distortion of the stock. 
It will be further appreciated that the sizing hoop very accurately 
controls the circumferential accuracy of the ring being formed at very 
high speed. The ring when expanded into the sizing hoop and cut may 
actually be less than a full circle, but when released, the cut product 
may then contract into a ring with the ends overlapped. It will be then 
expanded when the ends are later joined into a ring of the desired 
accurate circumference and diameter. 
With the present invention, a ring forming machine having substantially 
higher line speed is provided. The productivity of the line is 
substantially twice that employed with a flying cutoff. Also, the readily 
removable and replaceable sizing hoop permits rings of different diameter 
readily to be formed to a high degree of accuracy. For example, bicycle 
wheel rims of 27, 26 and 24 inches (68.58, 66.04, and 60.96 cm.) in 
diameter can be made on the same machine.