Title of Invention

AN IMPROVED SYSTEM FOR TILTING AND PUSHING OF HOT ROLLED RAILS WITH REDUCED SHARP BENDS/KINKS PRODUCED THEREIN

Abstract

The invention provides an improved system for tilting of hot rolled rails in head-up position on cooling bed skids in steel plants comprising a roller table with stopper for aligning ends of a set of rails placed on the roller table parallel to the length thereof, a cooling bed with a number of skids disposed parallelly at intervals along the length of the cooling bed and transversely to the length of the roller table, a number of pusher dogs each being connected to a common motor drive by means of a rope carriage, characterised in that the said system is provided with a straight bar assembly disposed across the cooling bed skids and having carriages welded to the bottom of the straight bar assembly of same number as that of the pusher dogs, a number of chains one each for connecting a carriage with a pusher dog lying in line thereof along the length of the cooling bed, a sloppy structure having triangular shape in vertical transverse section thereof and being welded onto the straight bar assembly along the entire length thereof, at least two actuator plates fabricated as intregal parts of the straight bar assembly and disposed parallel to the skids adjacent one each to at least two carriages and at least two stoppers which are rotatably fixed to the structure of the cooling bed lying one each in the path of movement of the at least two actuator blaes on the cooling bed along with the movement of the straight bar assembly in the directions towards and away from the roleaer table during the operation of the system.

Full Text

The present invention relates to an improved system for tilting and pushing of hot rolled rails with reduced sharp bends/kinks produced therein. In the existing system for straightening of hot rolled rails on cooling bed skids, a set of hot rolled rails, numbering typically 5-7, each of length 13 m, are first parallelly disposed along the length of a roller table and then pushed transversely along a number of parallelly disposed cooling bed skids, by means of, a number,typically 6, of pusher dogs, disposed one each in the space between the adjacent pairs of skids and parallel with the length of the skids. The pusher dogs are driven in the direction of the skids by means of rope carriages connected one to each dog at one end and to a common driving motor at the other end thereof. The rails are pushed laterally at their points of contact with the dogs and moved over the skids in the longitudinal direction thereof against the frictional resistance at the contacts between the rails and the skids. Because of the lateral pressure applied by the pusher dogs sharp bends/kinks are produced in the rails, which are required to be removed to the extent practicable by means of a roller straightening machine after the hot rails are cooled to ambient temperature in a slow cooling pit. But a sizeable proportion of the rails straightened in the existing system contains bends/kinks in excess of the stipulated limit of 0.7 mm in 1.5 m length, more commonly at the ends thereof. Such rails are either totally rejected or supplied as short length pieces by cutting off about 1 m length of the bent ends, leading to economic loss to the steel plants. - 2- The object of the present invention is to provide an improved system for straightening of hot rolled rails, in which the rails are pushed by lateral pressure applied uniformly at all points along their length and thereby the formation-of shar bends/kinks therein is reduced appreciably. The other object is to reduce the rejection of rails having bends/kinks in excess of the stipulated limit or the production of short length rails. Thus the invention provides an improved system for tilting and pushing of hot rolled rails with reduced sharp bends/kinks produced therein,comprising a roller table with stopper for aligning ends of a set of rails placed on the roller table parallel to the length thereof, a cooling bed with a number of skids disposed parallelly at intervals along the length of the cooling bed and transversely to the length of the roller table, a number of pusher dogs each being connected to a common motor drive by means of a rope carriage, characterised in that the said system is provided with a straight bar assembly disposet across the cooling bed skids and having carriages welded to the bottom of the straight bar assembly of same number as that of the pusher dogs, a number of chains one each for connecting a carriage with a pusher dog lying in line the reof along the length of the cooling bed, a sloppy structure having triangular shape in vertical transverse section thereof and welded onto the straight bar assembly along the entire length thereof, at least two actuator plates fabricated as intregal parts of the straight bar assembly and disposed parallel to the skids adjacent one each to at least two carriages and at least two stoppers which are - 3 - rotatably fixed to the structure of the cooling bed lying one each in the path of movement of the at least two actuator plates on the cooling bed along with the movement of the straight bar assembly in the directions tov/ards and av/ay from the rpiler table during the operation of the system. The invention is described fully and particularly in an unrestricted manner with reference to the accompanying drawings in which - Figure 1 is a plan view of the existing system for pushing of hot rolled rails on cooling bed skids; Figure 2A is a plan view of the invented system for tilting and pushing of hot rolled rails on coolipg bed skids; Figure 2B is a side view of the invented system shown in Fig. 2A; and Figure 3 illustrates the operational sequence of the invented system for tilting and pushing of hot rolled rails on cooling bed skids. Referring to Fig. 1, in the existing system a set of hot rails (2) is placed with their length lying across the length of skids (3) of a cooling bed (1). Six pusher dogs (4) driven by means of six rope carriages (5) having a common motor drive (not shown) are provided to push the set of rails laterally at six points marked (a) to (f) thereof. In operating the existing system the set of rails are first - 4 - placed along the length of a roller table (6) disposed transver; to length of the cooling bed and the ends of the rails are aligned by means of stopper (7). The rails are then pushed laterally and moved in the longitudinal direction of the coolin, bed over the skids by means of the six pusher dogs till the temperature of the hot rails falls to around 500°C2 when the same are transferred by means of a magnetic crane to a slow cooling pit and kept tiiere till their attaining the ambient temperature. Referring to Pigs. 2A and 2B, in the invented system a set of hot rails (2) is placed with their length across the length of seven skids (3) of a cooling bed (1) in the manner as in the existing system described above. Six pusher dogs (4) driven by six rope carriages (5), one connected to each dog, and all having a common motor drive (not shown) are provided to push a straight bar carriage assembly (8) having gix carriages (8') which are connected one each to six pusher dogs (A) by means of six chains (5A). A sloppy structure (9) having triangular shape in vertical plane is welded onto the straight bar assembly (8) along the entire length thereof lying across the cooling bed to make the assembly mechanically rigid. Six carriages (8'A to 8'F) are welded to the bottom of the assembly, being connected by means of six chains (5A) one each to six pusher dogs (4) which are in turn connected to a common motor drive (not shown) through six ropes (5). - 5 - Two actuator plates (10) are fabricated as integral part of the assembly and disposed parallel to the skids adjacent one each to carriages (8'B and 8'E). Two stoppers (11) are rotatably fixed to the structure of the cooling bed lying one each in the path of movement of the two actuator plates on the cooling bed along with the movement of the assembly during the operation of the system in the directions towards and away from the cooling table. The stoppers are each of right-angled trangular shape with the flat surface lying in a vertical plane having a hole (11 A) lying near its end bearing a right angle, and are each mounted rotatably in the vertical plane on an axis passing through the said hole and fitted to the cooling bed structure. The stoppers (11) remain normally in their sunk positions with the right-angled end in the uppermost position to allow passage of the assembly and the set of hot rails over them without obstruction. But during the movement of the straig bar assembly along with the pusher dogs towards or away from the roller table, the actuator plates moving along with the assembly push the stoppers at one of their right-angled sides and rotate the stoppers about their axes to support the said sides thereon and to retain the other right-angled sides of the stoppers raised in the vertically upward direction, as shown in Fig. 2B, and prevent thereby any movement of the rails on the cooling bed skids towards the roller table. - 6 - Referring to Fig. 3, in stage I of the operation of the invented system, the set of rails (2) and straight bar assembly (5) are pushed by the pusher dogs (A) towards the stoppers (11); in stage II, the set of rails (2) and straight bar assembly (8) are pushed over the stopper (11) in the direction away from the roller table (6) shown in Fig. 2A; in stage III, the set of rails (2) is pushed by the straight bar assembly (8) (moving towards the roller table (6)) against the stoppers (11) which are now in raised positions by the action of the actuator plates (10) to retain one of their right-angle sides in the vertically upward direction for pushing the set of rails (2) towards the straight bar assembly; and in stage I the set of rails (2) is tilted owing to their passing over and being dropped from the sloppy upper side of the straight bar assembly (8) so that heads(2A) of the set of rails are in the upward direction and bottom ends (2B) thereof are in the downward direction. The stoppers being then rotated to be in their normal sunk position by the action of actuator plates (1 the set of rails is pushed in the direction away from the roll table (6) by the straight bar assembly (8). The same sequence of operations is repeated for pushing of fresh sets of rails in the invented system. In the invented system the transportation of the set of rails is performed by pushing the same by the straight bar assembly uniformly along the entire length thereof in contrast to the existing system in which the pushing of the set of rails is carried out by pusher dogs at ---------------- - 7 - only six points (a to f in Fig. 1) distributed along the length thereof. Consequently the extent of rejections of straightened rails or cutting off at the ends of the straightened rails owing to bending thereof in excess of the stipulated limit is appreciably reduced in the invented syste: Comparative performance results of the existing and the invented systems are presented in Table I from which it is noted that the production of rails having bends in excess of the stipulated limit is appreciably reduced by using the invented system of straightening of hot rolled rails. TABLE I Comparative performance results of the existing and invented systems. Percentage Production of Rails having Existing System. Invented System. (a) Bend at ends not exceeding 0.7 mm in 1.5 mm length. 51 82 (b) Bend at ends being between 0.7 and 1.2 mm in 1.5 m length. 30 14 (c) Bend at ends being more than 1.2 mm in 1,5 m length. 19 k (d) 1 m length cut at each end. 15 3 - 8 - We Claim :- 1. An improved system for tilting and pushing of hot rolled rails with reduced sharp bends/kinks produced therein, comprising a roller table (6) with stopper (7), for aligning ends of a set of rails (2) placed on the roller table parallel to the length thereof, a cooling bed (1) with a number of' skids (3) disposed parallelly at intervals along the length of the cooling bed and transversely to the length of the roller table (6), a number of pusher dogs (4) each being connected to a common motor drive by means of a rope carriage (5), characterised in that the said system is provided with a straight bar assembly (8) dispose across the cooling bed skids and having carriages (8') welded to the bottom of the straight bar assembly of same number as that of the pusher dogs, a number of chains (5A) one each for connecting a carriage with a pusher, dog lying in line thereof along the length of the coding bed, a sloppy structure (9) havir triangular shape in vertical transverse section thereof and welded onto the straight bar assembly along the entire length thereof, at least two actuator plates (10) fabricated as intregar parts of the straight bar assembly and disposed parallel to the skids adjacent one each to at least two carriages (8'B and 8'E) and at least two stoppers (ii) which are rotatably fixed to the structure of the cooling bed lying one each in the path of movement of the at least two actuator plates (10) on the cooling bed along with the movement of the straight bar assembly in the directions towards and away from the roller table during the operation of the system. - 9- 2. The system as claimed in claim 1, wherein each stopper (11) is of right-angled triangular shape with the flat triangular surface thereof lying in a vertical plane and held in an horizontal axis passing through a hole (11A) lying near the end thereof bearing a right angle and fixed to the frame of the cooling bad. 3. An improved system for tilting and pushing of hot rolled rails with reduced sharp bends/kinks produced therein substantially as herein described and illustrated in the accompanying drawings. -10- Dated this 9th day of October 1998. The invention provides an improved system for tilting of hot rolled rails in head-up position on cooling bed skids in steel plants comprising a roller table with stopper for aligning ends of a set of rails placed on the roller table parallel to the length thereof, a cooling bed with a number of skids disposed parallelly at intervals along the length of the cooling bed and transversely to the length of the roller table, a number of pusher dogs each being connected to a common motor drive by means of a rope carriage, characterised in that the said system is provided with a straight bar assembly disposed across the cooling bed skids and having carriages welded to the bottom of the straight bar assembly of same number as that of the pusher dogs, a number of chains one each for connecting a carriage with a pusher dog lying in line thereof along the length of the cooling bed, a sloppy structure having triangular shape in vertical transverse section thereof and being welded onto the straight bar assembly along the entire length thereof, at least two actuator plates fabricated as intregal parts of the straight bar assembly and disposed parallel to the skids adjacent one each to at least two carriages and at least two stoppers which are rotatably fixed to the structure of the cooling bed lying one each in the path of movement of the at least two actuator blaes on the cooling bed along with the movement of the straight bar assembly in the directions towards and away from the roleaer table during the operation of the system.

Documents:

01788-cal-1998 abstract.pdf

01788-cal-1998 assignment.pdf

01788-cal-1998 claims.pdf

01788-cal-1998 correspondence.pdf

01788-cal-1998 description(complete).pdf

01788-cal-1998 drawings.pdf

01788-cal-1998 form-1.pdf

01788-cal-1998 form-2.pdf

01788-cal-1998 form-3.pdf

01788-cal-1998 form-5.pdf

01788-cal-1998 pa.pdf

1788-cal-1998-granted-abstract.pdf

1788-cal-1998-granted-assignment.pdf

1788-cal-1998-granted-claims.pdf

1788-cal-1998-granted-correspondence.pdf

1788-cal-1998-granted-description (complete).pdf

1788-cal-1998-granted-drawings.pdf

1788-cal-1998-granted-examination report.pdf

1788-cal-1998-granted-form 1.pdf

1788-cal-1998-granted-form 2.pdf

1788-cal-1998-granted-form 3.pdf

1788-cal-1998-granted-form 5.pdf

1788-cal-1998-granted-letter patent.pdf

1788-cal-1998-granted-pa.pdf

1788-cal-1998-granted-reply to examination report.pdf

1788-cal-1998-granted-specification.pdf