Patent Application
20170203347
This present disclosure relates to roll forming machines, specifically how the individual stations are driven. Each station has an upper roller and a lower roller that pinch the material to progressively shape it. Each roller must be rotationally driven to move the material along and assist the forming. Currently, the stations are all driven from one power source, commonly an electric motor. The shaft of the electric motor is affixed to a single gearbox, where the rotation from the motor is then divided up and split up into several output shafts, each driving a roller. For example, in U.S. Pat. No. 5,450,740, one gearbox drives several rollers. Because of slightly different speeds of both upper and lower rollers, along with slightly different speeds of the rollers from station to station, a fixed gearbox that provides the exact same rotational speed to each roller, binding and torque spikes can occur. Further, windup (where a biased torque builds up between two rotating members) causes uneven load, rapid tooling wear, roll scuffing of the material, and possibly catastrophic failure of the gearbox. An improved roll former and driving mechanism are needed.
The present disclosure describes an improvement to a roll former. As is known in the art, roll formers have a series of rollers. In this invention, each roller is driven independently, allowing significant flexibility in tooling and appropriate speed settings from roller to roller and station to station. Instead of a traditional gearbox arrangement, individual motors (electric or hydraulic) drive individual rollers. As is typical of a roll former, the individual output shafts of the motors are coupled to the rollers through shafts with flexible joints on each end. Frequently, each motor has its own gearbox to reduce the output speed and increase torque output, as roll forming lines can run slower than an optimum motor rotational speed. As material is fed into the machine, the operator can tailor speed and torque unique to each roller to optimize the process and reduce wasted power. The invention provides significant benefits over the prior art.
A preferred embodiment of this invention has been chosen wherein:
As is known in the art, a roll forming machine takes a flat strip of material and shapes it into a continuous cross-sectional desired shape, such as tubing. Frequently, the roll forming machine is a portion of a production line where the flat strip is provided to the machine from another machine, such as an uncoiler or slitter. After the machine makes the tubing, the tubing may be finished by other processes, such as cutting, end finishing, and stacking. This specification is primarily dedicated to the machine portion of the production line.
Referring first to the drawings of
The general process by which cylindrical tubing is formed from flat sheet steel is well-known and will not be described in detail in the interests of clarity. Generally, it is preferable if at least mill stands 13, 14, 15, 17, 23, 24, 25, 33, 35, 38, 39 and 40 are constructed according to the principles of this invention. Since the construction of these mill stands is generally the same, a detailed description will be provided only for mill stand 13 with the understanding that this general construction will apply to all affected mill stands which utilize the principles of this invention.
As an example, mill stand 14 is shown in elevation in
Power driven cylinder 50, typically a hydraulic cylinder having an extensible push rod 52 is fixedly secured to rails 48, 49 or to bracket 58 of drive frame 60 as shown. A lower connecting bracket 54 of frame 42 is connected to the terminal end of push rod 52 as by bolt 56 to allow for linear translation of movement between the push rod 52 and bracket 54.
Upright drive frame 60 is fixed to support table 62 by conventional means. Drive frame 60 carries spaced bearing blocks 64, 66. Lower bearing block 64 is fixedly connected to drive frame 60 and includes collar 68 and sleeve 70. Upper bearing block 66 is adjustably connected to drive frame 60 as by block 72 and jackscrew 74 and also has a collar 76 and sleeve 78. Motor 80 is supported atop drive frame 60 and includes rotatable drive shaft 82 which terminates in coupler 84. Drive shaft 82 extends through gear box 86 which is mechanically connected to jackscrew 74 so as to translate rotational movement of the drive shaft 82 into rotational movement of the jackscrew 74, and corresponding linear movement of bearing block 66.
As shown in
Frame 42 supports arbor frame 96 which includes spaced upright turrets 98 and 99. Plate 100 serves to connect turrets 98 and 99 and supports gear boxes 102 and 103. Gear boxes 102, 103 are used to drive height adjustment of upper arbors 114, 116. Couplings 104, 105 respectively are connected to and extend from gear boxes 102, 103. Jackscrews 106 and 107 extend through and are mechanically connected to gear boxes 102, 103 for translational movement.
Outboard housing turret 98 carries and supports bearing blocks 108, 109. Bearing block 108 is fixedly connected to turret housing 98 and is generally aligned with bearing block 64. Bearing block 109 is vertically adjustable and is connected to turret 98 as by block 110 connected to jackscrew 106. Turret 99 supports bearing blocks 111 and 112 in a similar fashion.
A first pair of rotatable arbors 113 and 114 is carried in bearing blocks 108 and 109. A second pair of arbors 115 and 116 is rotatably housed in bearing blocks 111 and 112. Forming rollers 117 and 118 are carried by and supported on arbors 113 and 114 respectively. The configuration and size of rollers 117, 118 will depend upon the predetermined size and desired shape of pipe to be formed, and by the position of the particular mill stand 13 in line 10. Since sheet steel is gradually bent to form pipe, the rollers 117, 118 will vary slightly in configuration as the line 10 progresses. The basic process of forming pipe from sheet steel is well known and does not form part of this invention. Collars 120 serve to secure rollers 117, 118 to arbors 113, 114 to prevent relative movement therebetween. In the embodiment shown, rollers 117 and 118 rotate along with arbors 113, 114 with no relative rotation taking place.
Arbor frame 96 includes a lower table 122 which is rotatably supported atop frame 42 as by bearing 124. Drive means (not shown) is connected to table 122 and serves to rotate the table about a vertical axis.
Arbors 115 and 116 are also adapted to carry rollers (shown in dotted line form) 127, 128. The construction of arbors 115, 116 is the same as arbors 113, 114. Each arbor 113-116 includes a driven feature 129, 130, 131, 132 which mates with driving feature 94 or 95, depending upon the position of the arbor, when the arbor frame 96 is in the work position.
Mill stand 14 is shown in the working or on-line position in
During operation, rotational movement of drive shafts 90, 91 rotates vertically spaced adjacent arbors 113, 114 and rollers 117, 118 that are fixed on their corresponding arbors 113, 114. Sheet steel is passed through the rollers 117, 118 to be bent. As shown in
When it is time to change rollers, such as when different wall thickness or pipe diameter is to be run, mill stand 14 need not be removed from the line 10 by crane, as previously required.
Arbor frame 96 is then rotated as indicated by arrow 126 to bring the standby arbors 115, 116 and rollers 127, 128 into the working alignment shown in
The above procedure is carried out for each mill stand along line 10 which requires that different rollers be used. By providing for the shiftable mill stands and rotatable turret heads, changeover and down time is significantly reduced with no loss in accuracy of roller settings. Further, the differential speed control of each of the rollers in the separate mill stands provides tailored control and reduced stress on the drive mechanism.
It is understood that while certain aspects of the disclosed subject matter have been shown and described, the disclosed subject matter is not limited thereto and encompasses various other embodiments and aspects. No specific limitation with respect to the specific embodiments disclosed herein is intended or should be inferred. Modifications may be made to the disclosed subject matter as set forth in the following claims.
