Arrangement for drawing transverse ribs

An arrangement for drawing transverse ribs onto smooth pipes, comprises a punch arranged to produce transverse ribs; a drive provided for driving the punch; a drawing bank carrying smooth pipes to be provided with ribs; driving chain means movable from the punch drive and including at least two continuously rotatable endless driver chains extending at a distance from one another and driving the transverse ribs; driving chain wheels arranged for driving the driver chains at their one end, the driving chain wheels having a driving shaft; and a coupling provided between the punch drive and the driving chain wheels at a drawing bank end which is opposite to the punch, the coupling including two claw discs which are bringable in form-locking and force-transmitting engagement with one another, one of the claw discs being freely rotatably arranged on the driving shaft on the driving chain wheel and at least indirectly actuatable from the punch drive, the other of the claw discs being connected with the driving shaft for joint rotation therewith, the other claw disc being axially displaceable under the action of a spring force in one axial direction and under the action of a fluid in the other axial direction on the driving shaft.

BACKGROUND OF THE INVENTION 
The present invention relates to an arrangement for drawing transverse ribs 
on smooth pipes. 
Arrangements of the above mentioned general type are known in the art. A 
known arrangement has a punch for producing transverse ribs, a drawing 
bank which carries smooth pipes to be provided with ribs, a driver chain 
transmission including at least two endless driver chains driveable from a 
punch drive over chain wheels and provided with drivers for transverse 
ribs, and a coupling arranged between the punch drive and the driving 
chain wheels of the driver chains. In such arrangements it is a problem to 
bring the drivers connected with the driver chains and provided for 
displacing transverse ribs for the punch, again to an exact taking 
position after disengagement of the driver chains from the punch drive, 
for example for the purpose of adjusting or when failures of the ribbing 
process take place. The coupling provided in this arrangement for this 
purpose is formed as a friction coupling in the drive train between the 
punch drive and the driving chain wheels located at the punch side of the 
drawing bank. By means of such a friction coupling it was also possible 
only with special labor and skill to bring the drivers to the proper 
receiving position during a repeated process. Additional difficulties take 
place when the ribs have different geometry. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide an 
arrangement of the above mentioned type which after repeated stoppages of 
the driver chains can guarantee the orderly position of the drivers for 
taking the punched transverse ribs during resumption of the operation, 
regardless of the geometry of the ribs. 
In keeping with these objects and with others which will become apparent 
hereinafter, one feature of the present invention resides, briefly stated, 
in that the coupling provided at the drawing bank and particularly at its 
end opposite to the punch has two claw discs which are bringable in 
form-locking and force-transmitting engagement with one another, where one 
claw disc is freely rotatable on the driving shaft of the driving chain 
wheels and at least indirectly driveable from the punch drive, for example 
via a driving wheel, while the other claw disc is arranged on the driving 
shaft for joint rotation therewith but axially displacably relative to the 
driving shaft in one axial direction under a spring action, for example of 
a spring, and in the other axial direction under fluid action, for 
example, of fluid-actuated cylinder-piston unit. 
The advantage of this arrangement is that now the coupling is arranged at 
the end of the drawing bank, which is opposite to the punch. In this case, 
the chain wheels located at this end can de driven and thereby the driver 
chains with the drivers which guide the transverse ribs are pulled. The 
process of applying the ribs takes place without jolts, even with very 
long smooth pipes to be ribbed (15 m and more) and also in the event of 
several pipes which are to be ribbed near one another up to approximately 
10 pipes). The quality of the pipes is decisively improved. 
Since the claw discs are bringable in form-locking and force-transmitting 
connection with one another, in connection with the axial displaceability 
of one of the claw discs on the driving shaft of the driving chain wheels, 
it is guaranteed that after the separation of both claw discs and 
subsequent engagement, always the proper driver position relative to the 
working cycle of the punch is available. By simple exchange of the claw 
discs the number of the claws can be changed, whereby a respective 
geometery of the ribs can be taken into consideration. The engagement of 
the claw discs is guaranteed by the mechanical spring force, while the 
fluid-operated cylinder-piston unit serves for disengagement of the claw 
discs from one another. As a result of this, only by the desired actuation 
of the cylinder-piston unit, an uncoupling of the driver chains from the 
punch drive can be performed. 
In accordance with a further feature of the present invention, the claws 
are arranged at the end side of each claw disc, and each claw is formed by 
two axially extending driving surfaces as well as a rectilineat transition 
surface extending between two driving surfaces at a small inclination 
relative to the plane normal to the axis of the driving shaft. In this 
construction it is guaranteed that driving of the driving shaft is 
performed only in one rotary direction. The toothing of the claw discs is 
formed in a zig-zag manner and has relatively short driving surfaces as 
compared with the length of the transition surfaces. Since the claws are 
provided at the end side of the claw discs, the coupling can be formed 
without projections in the circumferential direction. 
In accordance with a further feature of the present invention the spring is 
formed as a helical pressure spring and arranged between a cup-disc which 
is supported at the end of the driving shaft, on the one hand, and a 
flange of the cylinder of the cylinder-piston unit which engages the 
cup-disc and is connected with the rotary-fixed claw disc and the 
cylinder. In this construction the helical pressure spring and the 
cup-disc are located in a protected manner inside the flange connected 
with the cylinder. The connection of the flange with the associated 
rotary-fixed claw disc can be performed by uniformly circumferentially 
distributed screws. 
Still a further feature of the present invention is that the rotary-fixed 
connection of the driving shaft with one of the claw discs is performed by 
a groove-spring structure formed between the driving shaft and the flange. 
This is only an advantageous embodiment, since this connection can be 
performed by other means as well. As for the groove-spring structure, the 
driving shaft is provided with a groove in which a spring is located. The 
flange has an opening with a longitudinal groove which guarantees the 
rotary-fixed connection of the flange with the driving shaft and as a 
result with the claw disc. However, the axial displacement of the flange 
and the claw disc is provided. 
The cup-disc can abut against a clamping ring which is fixed at one end of 
the driving shaft. This provides easy mounting and demounting of the 
helical pressure spring. Also the cup-disc can favorably maintain the 
spring constant of the helical pressure spring so that the additional 
mounting space is not necessary. 
The cylinder of the cylinder-piston unit can be fixed on a cover disc which 
is mounted on the flange, and a piston rod can extend through the cover 
disc in direction toward the end surface of the driving shaft. The cover 
disc here closes the interior of the flange. Simultaneously, the cover 
disc serves for fixing the cylinder on the flange. For this purpose, screw 
can be uniformly distributed in a circumferential direction. The cylinder 
is screwed centrally into the cover disc. This facilitates the 
maintenance. The piston rod projects beyond the cover disc and in the 
extended position extends in the cup-disc. During actuation of the 
cylinder-piston unit, the piston rod is extended and supports against the 
end surface of the driving shaft, so that the claw discs, the flange, the 
cover disc, and the cylinder are displaced relative to the driving shaft. 
Finally, the cylinder-piston unit is pneumatically actuatable and coupled 
with a pneumetic rotary through-bearing or conduit. This is an especially 
advantageous embodiment for the specific conditions of the rib drawing 
machines. In addition to the pneumatically actuated cylinder-piston unit, 
also a hydraulically actuated cylinder-piston unit can be used. Also, an 
electromagnetic cylinder can also be provided. 
The novel features which are considered as characteristic for the invention 
are set forth in particular in the appended claims. The invention itself, 
however, both as to its construction and its method of operation, together 
with additional objects and advantages thereof, will be best understood 
from the following description of specific embodiments when read in 
connection with the accompanying drawings.

DESCRIPTION OF A PREFERRED EMBODIMENT 
An arrangement for drawing transverse ribs on smooth pipes includes a punch 
which punches desired transverse ribs from sheet plates and is identified 
in FIG. 1 with reference numeral 1. reference numeral The punch 1 has a 
punch drive identified with reference numeral 2. A drawing bank is 
identified with reference numeral 9. 
A chain transmission 3 is connected with the punch drive 2. It drives two 
driver chains 10 which rotate in vertical planes, via two angular 
transmissions 4, 5, hollow shaft 6 arranged between the angular 
transmissions 4, 5, a coupling 7, and a drive shaft 8 located at the end 
of the drawing bank 9 opposite to the punch 1. The driving chains 10 are 
guided over driving chain wheels 11 and deviating chain wheels 12 arranged 
at opposite ends of the drawing bank 9. The deviating chain wheels 12 can 
be supported displaceably in the longitudinal direction of the drawing 
bank 9 so as to allow tensioning of the driver chains 10. 
Not shown, drivers are arranged on the driver chains 10. They take the 
transverse ribs produced by the punch 1 in the region of the punch and 
move them onto smooth pipes which are arranged on the drawing bank 9 and 
not shown in the drawing. Up to ten smooth pipes can be simultaneously 
provided with ribs near one another. The smooth pipes can have a length of 
15 m and more. 
The procedure of drawing transverse ribs onto smooth tubes and specifics of 
the driving mechanism are disclosed in U.S. Pat. No. 3,095,639 which is 
incorporated here by reference. 
A coupling 7 shown in detail in FIG. 2 is provided between the angular 
transmission 5 and the driving shaft 8. It uncouples the driver chains 10 
from the punch drive 2 when it is necessary to perform adjusting works or 
when failures take place. 
The coupling 7 first of all includes a chain wheel 14 which is freely 
rotatably supported on the driving shaft 8 via a roller bearing 13. The 
chain wheel 14 is immovable relative to the driving shaft 8 in the axial 
direction. A driving chain 14' is guided over the chain wheel 14 and 
connected with an output shaft of the angular transmission 5. This 
arrangement is formed in that in practice the angular transmission 5 is 
located deeper than the driving shaft 8. 
A claw disc 15 is fixedly connected with the chain wheel 14. The connection 
is performed by means of screws 16 which are uniformly distributed in a 
circumferential direction. The claw disc 15 has end-side claws 17 which 
are formed by short driving surface 19 extending parallel to the axis 18 
of the driving shaft 8, and also by rectilinear surfaces 20 which extend 
between two driving surfaces 19 with a small inclination relative to a 
plane extending transverse to the axis 18 of the driving shaft. 
A further claw disc 21 is formed so as to be coupled only in a rotary 
direction with the claw disc 15 which rotates freely on the driving shaft 
8. The claw disc 21 also has claws 23 having driving surfaces 22 which 
extend parallel to the axis 18 of the driving shaft 8 and inclined 
transition surfaces 24. The claw disc 21 is connected with a hollow flange 
25 by screws 26 which are uniformly distributed in a circumferential 
direction. The claw disc 21 is also connected with the driving shaft 8 for 
joint rotation therewith, but axially displaceable relative to the driving 
shaft 8. This connection is performed by a groove-spring arrangement 27. 
The claw disc 21 is therefore displaceable axially and relative to the 
claw disc 16. The groove-spring arrangement 26 includes a spring 28 which 
is mounted in a groove 29 of the driving shaft 8, and also a longitudinal 
groove 30 in an opening 31 of the hollow flange 25. 
A clamping ring 32 is fixed at one end of the driving shaft 8. A cup-disc 
33 supports on the clamping ring 32. A helical pressure spring 36 is 
arranged between a radial collar 34 of the cup-disc 33 and a bottom 35 of 
the hollow flange 25. The helical pressure spring 36 serves for bringing 
the claw disc 21 into engagement with the claw disc 15 and holding the 
engagement. 
A cover disc 37 is mounted on the hollow flange 25 by means of 
circumferentially uniformly distributed screws 38. A cylinder 39 of a 
pneumatically operating cylinder-piston unit is screwed centrally into the 
cover disc 37. A piston rod 40 of the cylinder-piston unit extends into 
the cup-disc 33 and ends in the withdrawn ready position before an end 
surface 41 of the driving shaft 8. 
When the working medium is supplied into the cylinder 39 through a 
pneumatic rotary throughbearing 42, the piston rod 40 comes to abutment 
against the end surface 41 of the driving shaft end so that the cylinder 
39 together with the cover disc 37, the hollow flange 25 and the claw disc 
21 is displaced relative to the driving shaft 8 and engages the claw discs 
21 and 15 with one another. 
When the actuation of the cylinder-piston unit is terminated, the helical 
pressure spring 36 presses the claw discs 21 and 15 again toward one 
another so as to provide form-locking and force- transmitting connection, 
and thereby the drivers on the driver chains 10 take up the transverse 
ribs produced by the punch 1 exactly at a predetermined location which is 
dependent on the position and number of the claws 17, 23 and displace the 
transverse ribs without jolts onto the smooth pipes. 
It will be understood that each of the elements described above, or two or 
more together, may also find a useful application in other types of 
constructions differing from the types described above. 
While the invention has been illustrated and described as embodied in an 
arrangement for drawing transverse ribs onto small pipes, it is not 
intended to be limited to the details shown, since various modifications 
and structural changes may be made without departing in any way from the 
spirit of the present invention. 
Without further analysis, the foregoing will so fully reveal the gist of 
the present invention that others can, by applying current knowledge, 
readily adapt it for various applications without omitting features that, 
from the standpoint of prior art, fairly constitute essential 
characteristics of the generic or specific aspects of this invention.