GB2213752A - Apparatus for the taper rolling of metal - Google Patents

Abstract

Taper rolling apparatus includes a pair of rolls 10, 12 the spacing of which can be varied according to the linear movement of a workpiece clamped in a carriage assembly 26. So that the rolls can be made as short and therefore as stiff as possible, a leading end of the carriage assembly 26 is of tapered form and the housing structure 14 is cut sway so that the carriage assembly 26 is able to extend to within a short distance from the gap between the rolls 10, 12. <IMAGE>

Description

Apparatus for the taper rolling of metal.

The invention relates to apparatus for the taper rolling of metal, more specifically for the rolling of accurately tapered workpieces such as tapered leaf springs for vehicles.

It is known to taper roll a length of metal by drawing it between a pair of rolls and simultaneously varying the spacing between the rolls in accordance with the linear movement of the workpiece, the workpiece being connected to a drawbar arrangement by means of which it is drawn between the rolls, aided at least in part by a roll drive arrangement. The deformable blank workpiece will generally be drawn between the rolls a number of times to reduce it to the required form, and a pair of auxiliary rolls are disposed on the side of the main rolls remote from the drawbar arrangement, and in a plane perpendicular to a plane containing the axes of the main rolls, so that the lateral spread of the deformable blank can be controlled.

The main rolls may be driven with insufficient torque to drive the workpiece between them so that the drawbar pull provides a part of the force for passing the workpiece between the rolls.

It is necessary for the drawbar arrangement, on the output side of the main rolls, to be able to be brought into close proximity to the rolls.

Heretofore, this in turn has necessitated the width of the main rolls being considerably wider than the rolled product, solely because of the need for clamping mechanism forming part of the drawbar arrangement to be able to pass between the usual upstanding parts of the roll housing.

Consequently, the main rolls, and indeed the entire rolling installation, tend to be relatively expensive.

Because the main rolls have required to be relatively wide for the reason just explained, they have also required to be of a certain minimum diameter for adequate rigidity. Consequently, this has increased still further the cost of the rolls and in addition has resulted in some difficulty when a rapid change in thickness of the rolled product has been required, that is to say, a substantial variation in thickness over a relatively short length of the rolled product.

The invention has for its object to at least alleviate the drawbacks referred to above.

According to one aspect of the invention, there is provided apparatus for the taper rolling of metal including at least a pair of main rolls rotatably mounted between upstanding housing structure, a drawbar arrangement on the output side of said main rolls to which a heated workpiece blank can be connected to be drawn through a roll gap between said main rolls, and control means whereby the spacing between the main rolls can be varied in accordance with the linear movement of the workpiece, the drawbar arrangement including a carriage assembly having clamping means for connecting the heated blank thereto, said carriage assembly being mounted on pairs of rollers which guide it linearly along guide structure projecting rearwardly from the roll housing, a leading end of the carriage assembly being of tapered form and the housing structure at that side of the mill being cut away or relieved in such a way that the tapering leading end of the carriage assembly is able to extend to within a short distance from the gap between the main rolls despite the fact that the leading pair of rollers on which the carriage assembly is mounted do not enter the roll housing.

The clamping means carried by the carriage assembly will preferably be constituted by a pair of wedge members located between respective upstanding and converging walls at the tapering end portion of the carriage and respective clamping blocks which contact the side surfaces of the workpiece blank.

The wedge members may be connected by means of respective links and a slidably mounted yoke member to a hydraulic ram for driving the wedge members longitudinally of the carriage into operative or inoperative positions.

Respective roll chocks for upper and lower rolls defining the roll gap may be located by mechanism which ensures that the roll gap remains at a fixed height throughout the rolling operation, said mechanism including a horizontally disposed wedge member contrained to move along a horizontal path under the influence of the control means, one of the pair of roll chocks resting on or being suspended from an upper inclined surface of the wedge member and the other pair of roll chocks being retained in effect against the lower inclined surface of the wedge member or suspended from mechanism held in contact with the lower inclined surface of said wedge member, according to whether the wedge member is located above or below the rolls.

A pair of auxiliary rolls may be disposed on the side of the main rolls remote from the drawbar arrangement and in a plain perpendicular to a plane containing the axes of the main rolls so that lateral spread of the deformable blank can be controlled. Said pair of auxiliary rolls may be carried by respective bell-crank levers mounted on respective upstanding pivot pins, the positions of said auxiliary rolls towards or away from each other being controlled by respective double acting rams. The amount by which the auxiliary rolls can be brought towards each other, that is to say the setting which defines the minimum width of the rolled product, may be determined by the setting of adjusting screws which constitute positive stops acting against the frame of the roll stand.The frame of the roll stand and the roll chocks for the main rolls may be appropriately cut away to allow the auxiliary rolls to be positioned as close as possible to the main rolls.

The main rolls will preferably be constituted by a pair of rolls each of which is of greater diameter than its effective length and by a further roll located between said pair of rolls, said further roll being of smaller diameter than either of said pair of rolls, the roll gap being formed between the further roll and one of said pair of rolls, the other of said pair of rolls acting as a back-up roll for the further roll, the arrangement being such that by virtue of the relatively small diameter of the further roll a relatively rapid change of thickness of the workpiece can be effected, that is to say a substantial variation in thickness over a relatively short length of the rolled product.

In order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings, of which:- Figure 1 is a front elevation of apparatus embodying the invention, Figure 2 is a side elevation, Figure 3 is a plan view thereof, Figure 4 is a perspective view illustrating essential elements of the apparatus, and Figures 5 and 6 are schematic views which will be referred to when describing possible modifications.

Referring now to Figures 1 to 4 of the drawings, the apparatus there illustrated for the taper rolling of metal includes a pair of main rolls 10,12 mounted for rotation in a roll housing generally indicated 14, said main rolls being drivable, respectively, by means of universally jointed shafts 11 and 13. On the output side of the main rolls there is located a drawbar arrangement generally indicated 16 to which a heated blank can be connected, by clamping means generally indicated 18, the drawbar arrangement being movable linearly by a hydraulic ram 20.

The main rolls 10,12 define a roll gap through which the heated blank can be passed, control means (which will be described presently) being provided whereby, simultaneously, the spacing between the rolls can be varied in accordance with the linear movement of the workpiece. The deformable blank workpiece will in fact generally be drawn between the main rolls a number of times to reduce it to the required form. The heated blank is passed through the roll gap by means of the roll drive and drawbar pull in combination. It has been found necessary for the main force for driving the heated blank through the roll gap to be provided by the roll drive, but the drawbar pull has been found to be effective in maintaining the workpiece in straight condition as it passes between the main rolls.

A pair of auxiliary rolls 22,22 are disposed on the side of the main rolls remote from the drawbar arrangement, and in a plane perpendicular to a plane containing the axes of the main rolls, so that lateral spread of the deformable blank can be controlled. The auxiliary rolls will be brought into operation during at least one of the passes between the main rolls, and in fact it may be found that to control the lateral spread in the most effective manner they need to be brought into operation during each pass.

The clamping means 18, for connecting the heated blank to the drawbar arrangement, are located in a carriage assembly generally indicated 26. As shown in Figures 2 and 3, the carriage assembly is mounted on pairs of rollers 28,28 which together with further pairs of rollers 30,30 guide the carriage assembly linearly along fixed guide structure projecting rearwardly from the roll housing. The clamping means 18 are constituted by a pair of wedge members 32,32 which are located between respective upstanding and converging walls 34,34 at a tapering end portion of the carriage and respective clamping blocks 36,36 which contact the side surfaces of the heated workpiece blank.The wedge members are connected, by means of respective links 38,38 and a slidably mounted yoke member 40, to a hydraulic double acting ram 42 for driving the wedge members longitudinally of the carriage into operative or inoperative positions. Throughout the operation of the apparatus, the heated blank is traversed backwards and forwards between the main rolls at a constant height determined by its location in the carriage 26, the latter being traversable along the fixed guide structure.

Referring now in particular to Figures 1, 2 and 4, the main rolls 10,12 are located in respective pairs of roll chocks 44,44 and 46,46. The roll chocks 46,46 are seated on a lower cross block 48 which is connected, as shown, to upstanding slide columns 50,50 which are slidably mounted for vertical adjustment in vertical walls 52,52 of the roll housing. Together with an upper cross block 54, the lower cross block 48 connects the upstanding slide columns to form a sash-like frame slidably adjustable in the roll housing.

In an upper part of the roll housing there is located a horizontally disposed wedge member 56 which is constrained to move along a horizontal path by pairs of rollers 58 and 60 at its opposite ends which engage slots 62 and 64 respectively in the vertical walls of the roll housing. As shown, the wedge member is connected to a hydraulic ram 66 by means of which it can be traversed along its horizontal path of movement. The wedge member is symmetrical about its horizontal medial line as shown.

The upper cross block 54 which forms part of the sash-like frame referred to is seated on the upper inclined surface of the wedge member. Immediately below the wedge member and in contact with its lower inclined surface is an intermediate cross block 68 beneath which the roll chocks 44,44 are suspended. Consequently, it will be seen that as the wedge member is traversed along its horizontal path of movement by the hydraulic ram 66, the upper cross block and the intermediate cross block are moved towards or away from each other, depending upon the direction of movement of the wedge member, with equal and opposite movement. The rolls are thereby adjusted with equal and opposite movement to reduce or increase the roll gap about a constant height pass line.

The horizontal component of force which is applied to the upper and intermediate cross blocks when the wedge member is advanced to reduce the roll gap is taken by a pair of freely rotatable rollers 70,70 which are mounted in that side of the roll housing remote from the hydraulic ram 66.

The intermediate cross block 68 is retained in contact with the lower inclined surface of the wedge member by means of upstanding lug portions 72,72 of said cross block, these being provided with respective rollers 74,74 which engage slots 76,76 in the opposite side surfaces of the wedge member. The slots extend in parallel with the inclined lower surface of said wedge member so thst as the wedge member is traversed along its horizontal path, the intermediate cross block is caused to move up or down but is retained in contact with said wedge member at all times.

The arrangement is such that, as previously described, a heated blank can be drawn through the roll gap by the drawbar arrangement whilst the spacing between the rolls is simultaneously varied in accordance with the linear movement of the workpiece. This is of course done by pumping hydraulic fluid to the ram 66 at a rate dependent upon the rate at which the drawbar arrangement operates. (The control means referred to earlier may include means for generating a signal indicative of the progress of the material through the roll gap, means for generating a signal indicative of the desired spacing of the rolls according to the progress of the material through the roll gap, and means for indicating the actual spacing of the rolls, the rate at which hydraulic fluid is pumped to the ram 66 being varied in response to an error signal which is the result of a comparison between the desired spacing signal and the actual spacing signal). Throughout the rolling operation, the adjustment of the roll gap in the manner described maintains a constant pass line so that the heated blank is not subjected to bending about the region in which it is clamped upon the drawbar arrangement.The result is that the tapered product produced is of high quality and with no tendency to bend from the required straight form.

Referring now in particular to Figures 3 and 4, it will be seen that at the drawbar side of the mill, the upstanding slide columns 50,50 are generously cut away at 51,51 (and the adjacent housing walls are cut away similarly - see Figure 3). In Figure 3 in particular it can be seen that this feature, in combination with the fact that the carriage of the drawbar arrangement is of tapered form, allows the drawbar arrangement to be brought into close proximity to the main rolls. As shown, the leading pair of rollers 28 on which the carriage assembly is mounted do not enter the roll housing but the tapering leading end of the carriage where the clamping blocks 36,36 are located is able to extend to within a very short distance from the main rolls.

The pair of auxiliary rolls 22,22 which are disposed on the side of the main rolls remote from the drawbar arrangement are carried by respective bell-crank levers 78,78 mounted on respective upstanding pivot pins 80,80 carried by the roll housing. The positions of said auxiliary rolls towards or away from each other are controlled by respective double acting rams 82,82 the piston rods of which are pivotally connected to the bell-crank levers. The amount by which the auxiliary rolls can be brought towards each other, that is to say the setting which defines the minimum width of the rolled product, is determined by the setting of adjusting screws 84,84 which constitute positive stops acting against the frame of the roll stand.

As shown in Figures 2 and 3, the frame of the roll stand and the roll chocks are cut away in the region of the auxiliary rolls to allow the latter to be positioned as close as possible to the main rolls. It will be understood that the auxiliary rolls are located at a fixed height in the roll housing. Because of the fact that the roll gap is located at that same mean height, the cut away form of the roll chocks, and the complementary shaping of the bell crank levers, as shown in Figure 2, allows the auxiliary rolls to be located in very close proximity to the main rolls.

Thus there is provided apparatus for the taper rolling of metal the main rolls of which are relatively short. As can best be seen in Figure 3, the main rolls are only slightly wider than the workpiece being worked. In addition, the apparatus has very simple means whereby, throughout the rolling operation, the roll gap remains at a constant mean height so that a workpiece is not subjected to bending forces which could be of detriment to the finished product. It is particularly advantageous that the wedge member is located above the rolls because in this position it can be expected to remain free from scale and swarfe which could damage its working surfaces.

However, it is not essential for the wedge member to be located above the rolls, and in Figure 5 there is illustrated a modified arangement in which the wedge member is located beneath the rolls.

Referring to Figure 5, there is there illustrated schematically, an arrangement in which the wedge member 56 is located beneath the rolls. As shown, the wedge member is located between the lower cross block 48 and the intermediate block 68. The lower roll chocks 46 in this case rest upon the intermediate block. The upper roll chocks 44 are retained in abutment with the upper cross block 54 by means not shown.

The lower cross block 48 is in this case retained in contact with the lower inclined surface of the wedge member by means of rollers 74,74 which in this case are carried by the upstanding slide columns 50,50 which are slidably mounted for vertical adjustment in the vertical walls of the roll housing. As in the previously described embodiment, during traverse movements of the wedge member along its horizontal path of movement, guided by the pairs of rollers 58 and 60, the lower cross block 48 and the intermediate cross block are moved towards or away from each other, depending upon the direction of movement of the wedge member, with equal and opposite movement. The rolls are therefore adjusted with equal and opposite movement to reduce or increase the roll gap about the constant height pass line.

With the wedge member located beaneath the rolls, means will of course be taken to guard against the ingress of scale and swarfe to its working surfaces.

Because the basic construction of the mill has enabled the main rolls 10 and 12 to be made relatively narrow, they have also been able to be made somewhat smaller in diameter than in a conventional taper rolling mill (but it will be observed in Figures 1 and 3 that the rolls 10 and 12 are each of greater diameter than their effective length, that is to say their length between their respective pairs of roll chocks).

This relatively small diameter of said rolls has in turn enabled a more rapid change in thickness of the workpiece to be brought about than in a conventional mill. However, in Figure 6 there is illustrated a further possible modification by means of which an even more rapid change of thickness of the workpiece can be effected. As shown, the modification referred to comprises the addition of a further roll 86 freely rotatable in a further pair of roll chocks 88,88. The roll chocks 88,88 are retained in abutment with the roll chocks 44,44 by means not shown. In this way the roll gap is formed between the rolls 86 and 12, the roll 10 being merely a back-up roll for the roll 86.

It will be understood that the relatively small radius of the roll 86 enables a very rapid change in thickness of the workpiece to be brought about.

The roll 86 is able to be of a much smaller diameter than in a conventional taper rolling mill because of the fact that it has been possible to make it very much narrower for the reasons described above (since the back-up roll 10 merely supports the roll 86 against widening of the roll gap and not against deflections in the direction of travel of the workpiece).

In this latter modification, it is likely that the additional roll 86 would be an idler roll with the rolls 10 and 12 being driven. However, it is possible that the roll 86 and roll 12 could be driven rolls, part of the force for passing the workpiece through the roll gap being provided by the drawbar pull as in the previously described embodiments. It would be possible for a further small diameter roll to be added so that both rolls 10 and 12 became back-up rolls, but it is not thought that such further complexity would be justified since a sufficiently substantial variation in thickness of the rolled product over a relatively short length of the product can be obtained in an arrangement as illustrated in Figure 6.

Various other modifications may be made to the rolling mill apparatus described above. For example, the control means by which the spacing of the main rolls is varied in accordance with the linear movement of the workpiece can be of any preferred form.

Claims (10)

CLAIMS:

1. Apparatus for the taper rolling of metal, the apparatus including at least a pair of main rolls rotatably mounted between upstanding housing structure, a drawbar arrangement on the output side of said main rolls to which a heated workpiece blank an be connected to be drawn through a roll gap between said man rolls, and control means whereby the spacing between the main rolls can be varied in accordance with the linear movement of the workpiece, the drawbar arrangement including a carriage assembly having clamping means for connecting the heated blank thereto, said carriage assembly being mounted on pairs of rollers which guide it linearly along guide structure projecting rearwardly from the roll housing, a leading end of the cariage assembly being of tapered form and the housing structure at that side of the mill being cut away or relieved in such a way that the tapering leading end of the carriage assembly is able to extend to within a short distance from the gap between the main rolls despite the fact that the leadng pair of rollers on which the carriage assembly is mounted do not enter the roll housing.

2. Apparatus according to claim 1, in which the clamping means carried by the carriage assembly are constituted by a pair of wedge members located between respective upstanding and converging walls at the tapering end portion of the cariage and respective clamping blocks which contact the side surfaces of the workpiece blank.

3. Apparatus according to claim 2, in which the wedge members are connected by means of respective links and a slidably mounted yoke member to a hydraulic ram for driving the wedge members longitudinally of the carriage into operative or inoperative positions.

4. Aparatus accordng to any one of the preceding claims, in which respective roll chocks for upper and lower rolls defining the roll gap are located by mechanism which ensures that the roll gap remains at a fixed height throughout the rolling operation, said mechanism including a horizontally disposed wedge member contrained to move along a horizontal path under the influence of the control means, one of the pair of roll chocks resting on or being suspended from an upper inclined surface of the wedge member and the other pair of roll chocks being retained in effect against the lower inclined surface of the wedge member or suspended from mechanism held in contact with the lower inclined surface of said wedge member, according to whether the wedge member is located above or below the rolls.

5. Apparatus according to any one of the preceding claims, in which a pair of auxiliary rolls are disposed on the side of the main rolls remote from the drawbar arrangement and in a plain perpendicular to a plane containing the axes of the main rolls so that lateral spread of the deformable blank can be controlled.

6. Apparatus according to claim 5, in which the pair of uxiliary rolls are carried by respective bell-crank levers mounted on respective upstanding pivot pins, the positions of said auxiliary rolls towards or away from each other being controlled by respective double acting rams.

7. Apparatus according to claim 6, in which the amount by which the auxiliary rolls can be brought towards each other, that is to say the setting which defines the minimum width of the rolled product is determined by the setting of adjusting screws which constitute positive stops acting against the frame of the roll stand.

8. Apparatus according to any one of claims 5 to 7, in which the frame of the roll stand and the roll chocks for the main rolls are appropriately cut away to allow the auxiliary rolls to be positioned as close as possible to the main rolls.

9. Apparatus according to any one of the preceding claims, in which the main rolls are constituted by a pair of rolls each of which is of greater diameter than its effective length and by a further roll located between said pair of rolls, said further roll being of smaller diameter than either of said pair of rolls, the roll gap being formed between the further roll and one of said pair of rolls, the other of said pair of rolls acting as a back-up roll for the further roll, the arrangement being such that by virtue of the relatively small diameter of the further roll a relatively rapid change of thickness of the workpiece can be effected, that is to say a substantial variation in thickness over a relatively short length of the rolled product.

10. Apparatus for the taper rolling of metal constructed, arranged and adapted to operate substantially as hereinbefore described with reference to and as illustrated by Figures 1 to 4 or Figure 5 or Figure 6 of the accompanying drawings.