US2796780A - Conveying and cooling apparatus - Google Patents

Description

June 25, 1957 J. MBCGREGOR El'AL 2,795,780

CONVEYING AND COOLING APPARATUS A Filed July 10, 1953 4 Sheets-Sheet 1 INVENTORS. in James MacGregor no BY Herman E. Muller J1me 1957 J. M GREGOR ETAL 2,796,780

CONVEYING AND COOLING APPARATUS Filed July 10. 1953 4 Sheets-Sheet 2 Inn, I

IN VEN TORS.

James MacGregor 71/51]? A roams Y8 H rmanv E. Muller WM 4 Sheets-Sheet 3 J. M GREGOR ETAL CONVEYING AND COOLING APPARATUS June 25, 1957 Filed July 10, 1953 IN V EN TORS.

Jams Macregar ermpn E. Mu/l'er TO/EWEYS BY J June 25, 1957 J. M GREGOR ETAL 2,796,780

CONVEYING AND coouuc APPARATUS Filed July 10, 1953 4 Sheets-Sheet 4 Y INVENTORS. F I ll James Macregar BY Jjl-ljr man E. Muller Z/ Mi #AZL THE/R A TORIVE rs United States CONVEYING AND COQLMG APPARATUS Application July 10, 1953, Serial No. 367,225

3 Claims. (Cl. 80-42) This invention relates to conveying and cooling apparatus for rods, bars, pipes, billets, slabs, skelp, and like articles and, more particularly, to conveying and cooling apparatus for such articles as they come from a furnace in a still hot and semiplastic state.

It is known to use for this purpose a bed having several parallel racks or skids. Each rack has teeth which are staggered axially with respect to other teeth on the rack. A rod or similar article is fed to one side of the bed transversely to the racks, and, as the racks are rocked or pivoted back and forth in unison about a longitudinal axis, they pass the rod in a step-by-step fashion from one tooth to a succeeding tooth. During this time, the rod cools as it travels over the bed to the other side from where it is discharged. Since the rod or like article is still semipla'stic at the start of the cooling, the impacts inflicted on the rod by the edges of the teeth as it tumbles over the rack from tooth to tooth actually straighten the rod where it is not true.

There are several objections to such conveying or cooling beds as previously known. For one thing, the rod cools quickly so that only the first few rows of teeth transversely of the bed can effect the desirable straightening action. On the other hand, although the rod cools sufficiently to resist bending or straightening by the teeth it impinges against, the rod is still too hot to handle. Consequently, the beds must be of relatively large size, especially when very hot articles are to be processed, and accordingly such beds consume fairly large floor areas. Additionally, as the rod continues its travel across the bed, substantially the same areas on the rod are repeatedly struck by tooth after tooth. These repeated impacts mark or dent the rod especially when it is still somewhat plastic. Further, since the teeth are much colder than the rod, each contact causes localized chilling at the contact points and produces spots along the rod (chillspotting).

The speed of operation of a conveying or cooling bed of the type described is mainly dependent on the rate in which the racks are pivoted or rocked. customarily, the racks pivotally join a drive bar passing transversely beneath the racks and a double-acting prime mover connected to the drive bar moves it axially back and forth. In such a system, there must necessarily be a time lag as the prime mover completes a motion in one direction and then reverses. This time lag not only makes conventional conveying or cooling beds unsuited for quickacting performance when rods, pipes, etc. are delivered at a high rate, but the accumulation of such time lags can slow production when only a normal run-in speed is used.

Moreover, when a double-acting type of prime mover is employed, the drive bar and similar connections are under compression one-half of the time. Accordingly, these parts must be of suflicient size sectionally to withstand the compressive forces. ther slows the rate of pivoting and increases the described time lag. This problem is especially acute in conveying apparatus of exceptionally long length. In

The added weight required furatent 2 such a case, the size of a drive bar required and the correspondingly increased mass inertia the prime mover must overcome make it impractical to use a single drive bar. Instead, it may be necessary to use several drive bars, each controlling a diiferent set of racks. This is objectionable since the operation of all the racks is not then as smooth nor as synchronized as when only one drive bar is used.

The present invention provides apparatus that overcomes all these faults. This apparatus increases and concentrates the striking power of the teeth at the point where the rod first enters the bed and is most responsive to a straightening force. Since the rod, in any event, quickly cools below a straightening temperature, the present apparatus also provides greater initial cooling so that a smaller bed requiring smaller floor space is possible. The present apparatus also eliminates chillspotting of the article conveyed by having successive teeth along a rack contact different areas on the article as it travels over the bed. Additionally, the present apparatus provides a driving means which embodies cooperating single-acting prime movers which alternately pull the 'drive bar toward the mover then operating. By such a construction, the motion of the drive bar can be very quickly reversed, even before it would otherwise come to a stop. In such a situation, the time lag between reversal of directions is practically nil. Further, because the drive bar is always pulled and never under compression, a thin lightweight member can be used.

The accompanying drawings illustrate presently preferred embodiments of various features of the invention wherein:

Figure 1 is a plan view of one form of the present conveying and cooling apparatus showing a general arrangement of parts;

Figure 2 is a section of Figure 1 on the line 11-11;

Figure 3 is a section of Figure l on the line III-III;

Figure 4 is a plan view of one of the racks of Figure 1 showing the rack pivoted to one extreme position and the non-uniform pitch of the teeth;

Figure 5 is a section of Figure 4 on the line V-V;

Figure 6 is a section of Figure 1 on the line VI-VI;

Figure 7 is a section of Figure 6 on the line VII--VII;

Figure 8 is a plan view of the pivot pin baring of Figure 7;

Figure 9 is a plan view similar to that of Figure 1 but showing the racks skewed;

Figure 10 is an offset section of Figure 9 on the line XX and illustrates a drive means for the skewed racks; and

Figure 11 is a plan view similar to Figure 9 but showing a modified driving means for the skewed racks.

Referring principally to Figures 1 through 5, the embodiment here shown includes a plurality of parallel, spaced-apart, substantially coplanar racks 15. Each rack has converging sides 11 forming a V-shaped trough. Each side has triangular teeth 12. Each tooth has sides of unequal length, the sides away from the direction of travel of the rods being longer. The teeth slant as a result of the unequal sides, and all the teeth point in the same direction while the pitch of the teeth decreases in a direction opposite to the slant. Also, each tooth is staggered lengthwise of the rack with respect to teeth on the other side of the rack. The apex of the trough is joined to pivot pins 13 free to rotate in bearings 14.

As shown in Figures 6, 7, and 8, the bearings 14 include a block 15a having a recess 16 to receive the pivot pin 13. Stops 17 fixed at the ends of the block 15a prevent the pin from sliding out of its seat. A tap and side opening 18 communicate through the vertical passage 19 with the contact area between the pivot pin and block to provide for lubrication of those parts. of the lubricant.

Pockets 20 retain some A plate 21 carries the block 15a and in turn is bolted to an angle iron 22 passing under the plate 21 and transversely beneath the racks. Suitable posts 23 :support the angle iron at its ends as shown in Figures 2 and 3.

Referring again to Figures 1 and 2, rocker arms 24 depend from the racks and pivotally join a cross bar 25 passing transversely therebeneath. Single-acting hydraulic cylinders 26 connect to the ends of the cross bar through connecting rods 27. Each rod pivotally joins at one end to the cross bar 25 and at the other to a piston rod 28 of cylinders 26.

Suitable transferring means advance rods, bars, pipes, slabs, and like articles to the entrance end of the racks and receive such articles as they are ejected from the racks. For example, as illustrated in Figures 3, 4, and 5, standard roller tables may be used. Rollers 2-9 are spaced between the racks 15, journaled in support walls 30, and rotated by a conventional bevel gearing or pinion drive generally shown at 31. The entrance end of each rack is the end toward which the triangular teeth 12 slant and ordinarily has teeth of the greatest pitch. The entrance end also terminates in a plate 32 fixed edgewise to the ends of the sides 11 of the trough comprising the rack. One end 33 of the plate 32 slopes toward the rack to lift rods and like articles. The plate has an integral guide rail 34 and is reinforced by a rib 35. A roller table receives the rods and bars as they are ejected from the exit end of the racks. A standard bevel gear or pinion drive generally shown at 36 rotates the rollers 37 which are journaled in support walls 38.

The embodiments illustrated in Figures 9 and 11 are the same as that just described except that the racks 115 are skewed, that is, their longitudinal axes form an acute angle with an article 39 being conveyed. While it is not necessary to vary the pitch of the teeth of the skewed racks 115 to realize the advantage of the skewed arrangement, the concurrent use of both novel features is preferable since each complements the other to produce a greatly improved conveying and cooling apparatus.

When very long apparatus of the present type is used, it may be desirable to ofiset the drive arrangement of Figures 1 and 2 in the manner shown by Figures 9 and 10. In this case, the single-acting cylinders 26 are retained, but the cross bar is divided into two sections 40 and 41 which are interconnected by the offset station 42. Each section'has a lug 43 whichconnecting rods 44 straddle in a pivotal connection. The rods 44, similarly join at their other ends a lever 45 which is fixed to a shaft 46 pivoted in a bearing 43. In this manner, pulling one section also pulls the other. When very long apparatus is used, it may be desirable to offset the cross bar at a plurality of points as shown in Figure 11. station 49 is similar to station 42 of Figure 9 and has straddling connecting rods 50, while the offset stations 51 have single interconnecting pitmans 52.

In operation, rods, bars, pipes, slabs, and like articles are run in, as from a hot mill furnace, over the rollers 29 in the direction of arrow 53 of Figure 1. Between each run-in of a rod or rods, each of the hydraulic cylinders 26 alternately pulls the cross bar 25 once and thereby the cylinders together pivot the racks back and forth once in unison about a longitudinal axis. The operation of the hydraulic cylinders may be manually performed, but usually a conventional timing mechanism is usedto synchronize the rocking of the racks with the run-in of articles of the type mentioned. Initially, the rack is in a tilted position as shown in Figures 4 and 5, so that the plate 32 is below the upper surfaces of the rollers 29 and the rods, bars,

or pipes pass over it. Thereafter, as the racks are pivoted as described, the plate 32 rises, and the sloping edge 33 contacts a rod or like article and forces it over onto the racks. When the racks are next pivoted in the opposite direction, the rod just received has dropped into the position of rod 54 in Figure 3, and the plate 32 descends b'e Here the central ofiset tween the rollers 29 to be in position to receive the next Because the pitch of the teeth is greatest at the entrance end of the racks, it is there that a hot semiplastic rod receives the greatest straightening impact as the rod strikes against the teeth, since the rod climbs and falls the greatest distance at this time. To this end, the pitch of the teeth at the entrance end may be greater than that ordinarily employed in a rack having teeth of a uniform pitch. Also, since the rod, in any event, cools quickly below the temperature at which it is so responsive to a straightening impact, the greater pitch of the teeth spaces the rods farther apart and makes them more accessible to cooling air flowing therebetween. This shortens the length of apparatus required and, accordingly reduces the floor area needed. By continuously decreasing the pitch of the teeth in a direction toward the exit end, a further reduction in required floor area is possible, because this construction has the effect of literally shrinking the length of the racks without decreasing the number of times the rod is passed from tooth to tooth. Moreover, the travel of the rod becomes much smoother.

During this time also, the racks are pivoted more often than heretofore by virtue of the single acting cylinders 26 which alternately pull on the cross bar without waiting for the prior movement to come to a normal stop in which time lags inherent in a normal reversal of direction are otherwise accumulated. Further, since only a tensile force is involved as compared to a compressive force, the cross bar 25 and accessory parts may be made of a light metal having a relatively small cross section which further aids in the reciprocal driving of the cross bar.

In the event the racks are skewed as in Figures 9 and 10, consecutive teeth on each of the skewed racks contact successively different areas on the rod as it travels over the bed and thereby eliminate chill-spotting. As the rod is ejected from the last row of teeth transversely across the racks, the rollers 37 receive the rod and carry it away in the direction of the arrow 47 of Figure 1.

Various modifications are possible with the present invention. The change in pitch does not necessarily have to be continuous in one direction. For example, one pitch can be used for the teeth at the ends of the rack and a smaller pitch employed in the central portion as when one speed is desired at the ends and a slower action in the middle of the rack. Further, the change in pitch need not be continuous from tooth to tooth but can be by sections. Still further, the V-shaped rack need not be used. Instead, fiat parallel bars pivoted at each end can be employed with teeth out in one edge and staggered with respect to similar teeth on an adjacent bar to provide the described action. Nor need a rocking motion be used on the racks. As an alternative, an X-shaped rack may be used which is rotated continuously in one direction about a longitudinal axis so that each of the four edges consecutively contact a rod and wherein the teeth of the four edges are staggered with respect to each other to provide the described action.

While the foregoing disclosure describes several presently preferred embodiments of the present invention, it is understood that the invention may be practiced in other forms and with other modifications within the scope of the following claims.

We claim:

1. Conveying apparatus for rods, bars, and like articles including a plurality of substantially parallel racks, each rack having at least two rows of teeth extending parallel to the longitudinal axis of the rack, the teeth of one row being staggered with respect to the teeth of the other row, the pitch of corresponding teeth in both rows varying along the length of the rack and means for alternately raising one row of teeth above the other whereby rods, bars, and like articles placed at one end of the racks will be moved to the other end of the racks at speeds varying in accordance with the pitch of the teeth.

2. Conveying apparatus for rods, bars, and like articles including a plurality of substantially parallel racks, each rack having at least two rows of teeth extending parallel to the longitudinal axis of the rack, the teeth of one row being staggered with respect to the teeth of the other row, the pitch of corresponding teeth in both rows decreasing in the direction of travel of rods, bars, and like articles across the apparatus and means for alternately raising one row of teeth above the other whereby rods, bars, and like articles placed at one end of the racks will be moved to the other end of the racks at speeds varying in accordance with the pitch of the teeth.

3. Conveying apparatus for rods, bars, and like articles including a plurality of substantially parallel racks each having at least one row of teeth extending parallel to the longitudinal axis of the rack, the teeth in alternate rows being in line with each other and the teeth in adjacent rows being staggered with respect to each other, the pitch of the teeth in all rows varying along the length of the rack and means for alternately raising the two sets of racks having teeth in line with each other whereby rods, bars, and like articles placed at one end of the racks will be moved to the other end of the racks at speeds varying in accordance with the pitch of the teeth.

References Cited in the file of this patent UNITED STATES PATENTS 1,139,027 George May 11, 1915' 1,352,766 Shepardson Sept. 14, 1920 1,484,665 Nelson Feb. 26, 1924 1,691,645 Dahlstrom Nov. 13, 1928 2,327,734 Morgan Aug. 24, 1943 FOREIGN PATENTS 178,171 Germany Nov. 15, 1906 615,564 France Jan. 11, 1927

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