US2777331A - Automatic guides for travelling bands or belts - Google Patents

Description

Jan. 15, 1957 J. CRUICKSHANKS 2,777,331

AUTOMATIC GUIDES FOR TRAVELLING BANDS OR BELTS Filed Oct. 28, 1952 4 Sheets-Sheet l FIG. 7

Jan. 15, 1957 u c 5 A s 2,777,331

AUTOMATIC GUIDES FOR TRAVELLING BANDS 0R BELTS Filed Oct. 28. 1952 4 Sheets-Sheet 2 n- 1957 J. CRUICKSHANKS 2,777,331

AUTOMATIC GUIDES FOR TRAVELLING BANDS 0R BELTS Fi led Oct. 28, 1952 4 Sheets-Sheet 5 1957 J. CRUICKSHANKS 2,777,331

AUTOMATIC cums FOR TRAVELLING BANDS 0R BELTS Filed Oct. 28, 1952 4 Sheets-Sheet 4 United States Patent AUTOMATIC GUIDES FOR TRAVELLING BANDS OR BELTS John Cruickshanks, Edinburgh, Scotland, assignor to Bertrams Limited, Edinburgh, Scotland Application October 28, 1952, Serial No. 317,341

Claims priority, application Great Britain October 29, 1Q51 2 Claims. (Cl. 74-241) This invention relates to automatic guides for travelling bands or belts, such as the wire of a Fourdrinier papermaking machine to which the present invention is particularly, but not exclusively applicable.

Each such guide consists fundamentally of a guide roller, over which the band or belt is arranged to travel, means for eifecting angular adjustment of the axis of the said guide roller relative to a normal position at right angles to the direction of movement of the band or belt, a feeler movable by engagement of the band or belt therewith when the belt moves laterally out of its intended normal running position and means adapted to be actuated by the movement of said feeler for motivating the angular adjustment means aforesaid to correct the said lateral movement of the belt. Such guides are hereinafter termed automatic guides of the kind referred to.

One of the main problems with such automatic guides is the tendency for hunting, that is to say, unless they are set with a wider tolerance than should be necessary they operate to adjust the guide roller first in one direction and then almost immediately in the other direction and so on backwards and forwards causing the band or belt to be moved ceaselessly first to one side and then to the other of the intended or normal running position.

The present invention is based upon a fuller appreciation than heretofore not only of the cause of such hunting but of the possibilities of correcting the same. In

the first place it is fairly obvious that hunting is caused by a de-activating time-lag, i. e. the time-lag between the adjustment of the guide roll into a new angular position and before the full effect of such adjustment has been transferred to the band or belt. Consequently the feeler continues to motivate adjustment for some time after the correct adjustment of the guide roller has actually been made, that is to say after the amount of adjustment has been made which, given time, would be suflicient to correct the displacement of the band or belt which initiated such adjusting movement. That however is only one factor and the most obvious at that. Another and less obvious factor is the activating time-lag, i. e. the time-lag between the moment when the feeler is moved past a critical position and motivates the adjusting means and the time required by such adjusting means to provide an effective movement of the'guide roller. All such adjusting means have not only been slow in action, probably purposely so to try and reduce the violence or rapidity of hunting, but also they have acted at one set speed unrelated to the urgency or otherwise of the need for adjustment, that is to say the rate of adjustment of the guide roller is the same whether the band or belt is an inch or 6 inches off its proper alignment, and this is another factor operating adversely to the efficient action of an automatic guide.

The present invention appreciates therefore that a better and more efliciently operating automatic guide can be provided by removing one or both of the char- ..acteristics of existing devices which give rise to the 2,777,331 Patented Jan. 15, 1957 belt so as to provide earlier demotivation of the adjusting means.

According to a further feature of the invention the adjusting means for the guide roller includes means the speed of actuation of which is proportional to the lineal displacement of the feeler beyond its critical motivating position, whereby the speed of adjustment of the guide roller is proportional to the need for adjustment.

In the accompanying drawings:

Fig. l is a part sectional side elevation showing one end of a guide roller and its control mechanism made in accordance with one example of the invention;

Fig. 2 is a plan of Fig. 1 showing the same end of the guide roller and its mechanism;

,Fig. 3 is a part sectional end elevation on line 3--3 of Fig. 2 showing the same end of the guide roller;

Figs. 4, 5 and 6 are exaggerated line diagrams illustrating the functional movements of the control mechanism;

Fig. 7 is a part-sectional plan view similar to Fig. 2 but illustrating an alternative arrangement, and

Fig. 8 is a sectional plan view of the valve of the arrangement shown in Fig. 7.

In the example of the invention shown in the drawings the wire guide roller (1 of a Fourdrinier machine is mounted in the usual manner that is to say the bearing housing a at each end of the roller includes a stem b for pivotal movement, While at one end as shown in the drawing the bearing block c is slidably adjustable in guides c to enable the angular relation of the guide roller to the belt d to be changed. Instead of the usual adjusting means consisting of a feed screw and ratchet actuating means for turning the screw, hydraulic rams e, e are provided at each side respectively of the bearing block 0, the cylinders having brackets f, f by which they are rigidily attached to the frame g of the machine and the pistons being attached by the piston rods h, h to the bearing block 0. On the bearing block is mounted by means of a mounting a hydraulic valve consisting of a cylindrical housing i in which is rotatably mounted a control vane 2' In the housing are a pair of ports 1', f in diametrically opposed relation connected by flexible piping k, k respectively to the outer ends of the hydraulic cylinders. Also in the housing and disposed at right angles to the two first mentioned ports and diametrically opposite to each other are inlet and exhaust ports I, I connected to the pressure and return pipe lines of a pump or other means (not shown) for providing hydraulic pressure. The control vane i of the valve is adapted to be actuated by a feeler consisting of a palm or plate-like member n7 attached one to each end of a rod m which is slidably mounted in guides (not shown) adjacent to the edges of the band or belt d. The palms on opposite sides of the band or belt d are adjustably secured by bolts m? to the rod m and are set spaced apart a distance slightly greater than the width of the band or belt so that while the belt is running reasonably true and centrally with the guide roller a normal to the run of the belt, neither edge of the belt will engage its adjacent palm. The sliding rod m carrying the two palms is connected to one arm of a bell-crank lever n pointing rearwardly relative to the run of the belt, the other end n of which lever extends outwardly and parallel to a lever 0 secured to the spindle of the control vane i and is connected thereto by a link p. A centering spring 0 is provided on the valve lever. A bracket y extends outwardly from the base y and is provided with an upwardly extending body portion z upon which the arms 11 and n of the bell crank lever are pivotally mounted.

In operation, as shown particularly in Figs. 4, 5 and 6, if the band or belt d wanders to one side or the other of its normal position its edge will engage and push the palm 121 thus immediately turning the valve vane one way. The parts are shown in Fig. 4 in their normal initial set positions. Such movement of the belt to the dotted line position :5 inclines both the arms 11 and o and moves the vane to open the port j connected to the cylinder 0 to the pressure inlet port I and at the same time connects the other port j to the outlet port 1 The hydraulic pressure fluid entering the left hand cylinder immediately initiates movement of the piston 12 causing the other piston 11 to expel fluid from its cylinder. The resultant movement of the bearing block 0 being dependent on the rate of flow of the fiuid is therefore, directly dependent on the amount of movement of the vane i and therefore of the palm m. A very rapid movement of: the bearing block c carrying the guide roller bearing housing a may therefore be provided, and as the movement imparted to the palm will necessarily be in the form of periodic impulses due to irregularities in the run of the edge of the belt, the sensitivity of the arrangement may be so set that an almost instantaneous adjustment movement is obtained from a high part of the run of the belt. By high part of the belt is meant any part of the edge of the belt whichiis out of line with the remainder of the edge of the belt, for example by reason of any deformation of the belt. Over adjustment movement is avoided partly by the sensitivity of such hydraulic control to the high part which may release the palm by passing it before adjustment movement of the guide roller has had time to move the belt across. In addition to this however, it is to be noted from Fig. 6 that any adjustment to the right of the guide roller bearing block C also operates through the lever and linkage to effect re-centralizing of the valve although the palm may still remain displaced as if in contact with the belt shown in the chain line position (1 The valve vane can therefore de-motivate the hydraulic ram 0 before the edge of the belt allows the palm to return to its original position and although the result is a permanent relative displace ment of the palms from their on'ginal position, such displacement is only small and immaterial under normal conditions compared with the check which it puts upon any tendency to hunt. After such adjustment of the guide roller, the belt will, in due time run away from the palm which it had just actuated but not so far as to engage the other palm because the adjustment motivation of the guide roller has been, at least in part, checked by the closing of the valve from the combined movement of the palm and the lateral adjustment movement of the bearing block 0. The ultimate result of this lateral adjustment of the palms is that they can be set closer to the run of the high parts than has hitherto been possible because of hunting and thereby the guide is given greater sensitivity.

In Fig. 7 is illustrated an alternative arrangement in which the function of pistons 2 e and cylinders F, f are the reverse of the functions of the corresponding parts of the embodiment previously described. The pis tons e e are rigidly fixed on the machine frame whilst the cylinders f 1' (which are integral) are supported for sliding movement in guide c and carry a hydraulic valve consisting of an ellipsoidal housing 1' in which is rotatably mounted a control member i (see Fig. 8).

The valve body 1' is bolted to the walls of the cylinders f and f Passages and associated ports are provided within the valve for inlet and outlet of hydraulic fluid, which is conveniently water under pressure, but may equally well be compressed air or oil under pressure. Thus, there are inlet passages f and f in the walls of the cylinders, complementary passages 1' and i in the body of the valve leading to the housing 1' an inlet socket i also leading to the housing 1', an outlet passage 1' from the housing i and an outlet hole 1' from the last passage for return flow.

In operation the alternative arrangement just described is exactly the same as the arrangement shown in Figs. 1 to 6, except that the movable elements are cylinders and the stationary elements pistons. It will be clear that one advantage of this is that flexible pipe connections are no longer necessary, which cheapens and simplifies the design.

I claim:

1. Apparatus for controlling the transverse position of a horizontal travelling band trained on a rotating roll comprising, a support, a shiftable bearing means for journalling the rotating roll and including a pivotable stern whereby the angular position of the axis of the rotating roll is shiftable with respect to the path of the travelling band, a pair ol": guides fixed to said support at one end of the rotating roll, a slidable bearing block adjustable between said guides and supporting the stem of said shiftable bearing means, a pair of hydraulic cylinders, each of said hydraulic cylinders secured to said support at :1 side of said slidable bearing block and having a piston reciprocable therein and provided with a piston rod fixed to said slidable bearing block, an hydraulic valve mounted on said slidable bearing block and having iii) a control vane rotatably mounted therein and connected to each or: said hydraulic cylinders for adjusting said slidable bearing block. angularly relative to a normal operating position at right angles to the direction of movement of the travelling hand, pump means connected to said hydraulic valve for supplying hydraulic pressure thereto, a feeler member on each side of the travelling band and being responsive to changes in the transverse position of the travelling band with respect to the rotating roll, a bell crank lever pivotally mounted on said support, a shiftable feeler rod connecting said feeler members to said bell crank lever, and a link connecting said bell crank lever to the control vane of said hydraulic valve, all adapted and arranged with the edge of the travelling band engaging and actuating said feeler members with said feeler rod and bell crank and link and the control of said hydraulic valve being responsive thereto and effecting actuation of said hydraulic cylinders and slidable bearing block therebetween whereby the adjusting movement of said bearing means away from its normal position is accomplished to maintain the travelling band in a desired transverse position on the rotating roll.

2. The apparatus of claim 1 with the movement of the rotating roll to normal position simultaneously effecting return actuation of said feeler members to their original undisplaced positions.

References Cited in the file of this patent UNITED STATES PATENTS 1,066,687 Warren .luly 8, 1313 2,199,893 Norton et al. May 7, 1946 2,291,830 Obenshain Aug. 4, 1942 2,488,294 Hornbostel .d Nov. 15, 1949 2,632,642 Cooper Mar. 24, 1953

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