US3793868A

US3793868A - Taper-rolling of metal

Info

Publication number: US3793868A
Application number: US00290657A
Authority: US
Inventors: A Wilson
Original assignee: Hille Engineering Co Ltd
Current assignee: Hille Engineering Co Ltd
Priority date: 1971-09-24
Filing date: 1972-09-20
Publication date: 1974-02-26
Anticipated expiration: 1991-02-26
Also published as: GB1380691A; DE2246693A1

Abstract

A method of taper rolling for producing leaf springs and the like, including the step of reducing the width of the deformable blank, between a pair of auxiliary rolls, to a width somewhat less than the required final width so that during a final ''''pass'''' between a pair of main rolls the blank returns to the required final width as it is brought to the required taper form.

Description

I United States Patent 1 1 1111 3,793,868

Wilson Feb. 26, 1974 [5 TAPER-ROLLING 0F METAL 666,851 1 1901 Lanz 72/365 2,353,289 7/l944 Bennewitz... 72/235 [75] Invent Alexander Sheffield 3,417,592 12/1968 Fielding 72/199 England 3,490,261 1 1970 12w 72/240 Assignee: The Engineering p y 3,534,576 10/1970 Abernathy et al. 72/240 Limited, Sheffield, England [22] Filed: SepL 1972 Primary Examiner-Lowell A. Larson [2]] Appl. No.: 290,657

[30] Foreign Application Priority Data ABSTRACT Sept. 24, 1971 Great Br1ta1n 44745/71 [52 us. 01 72/226, 72/240, 72 250, A method of taper rolling for Producing leaf Springs 72 3 and the like, including the step of reducing the width' [51] Int. Cl B21b 1/42 of the deformable blank, between a p of auxiliary 5 Field f Search 72 221 222 225 22 3 5 rolls, to a width somewhat less than the required final 72/3 240 250 width so that during a final pass between a pair of main rolls the blank returns to the required final width [56] References Ci d as it is brought to the required taper form.

UNITED STATES PATENTS 607,] I0 7/1898 Brooker 72/250 10 Claims, 10 Drawing Figures PMENTED 3.793.868

SHEET 3 [IF 9 PAFENTEDFEBZBIQM 3.793.868 sum u UF 9 TAPER-ROLLING OF METAL The invention relates to the taper-rolling of metal and has for its object to provide an improvement therein.

Single taper leaf springs are now used for vehicle suspensions, and when producing such a spring by rolling it is necessary to control the degree of taper very accurately, that is to say from its mid-portion towards its opposite ends. it is this development which has shown the need for an improved method of and apparatus for the taper-rolling of metal and in our prior Application for US. Pat. No. 144,525 of 1971 there is proposed a method for the taper-rolling of metal which includes the steps of drawing a deformable blank between a pair of rolls and simultaneously controlling the position of at least one of said rolls in accordance with the linear movement of a drawbar for drawing said blank between the rolls. However, it has been found difficult to control the width of the rolled product produced by this method and the object of the present invention is to at least alleviate this problem.

According to one aspect of the invention, there is provided an improvement in or modification of the invention claimed in our prior Application for US. Pat. No. 144,525 of 1971 comprising a method for the taper-rolling of metal including the steps of drawing a deformable blank between a pair of rolls and simultaneously controlling the position of at least one of said rolls in accordance with the linear movement of a drawbar for drawing said blank between the rolls, the improvement or modification residing in the fact that the deformable blank is drawn between the said rolls a number of times to reduce it to the required form, and before a final pass is effected the blank is reduced in width between a pair of auxiliary rolls to bring it to a width somewhat less than the required final width so that during the final pass between the first mentioned pair of rolls, that is to say the main rolls, the blank returns to said required width as it is brought to the required final taper form. The method may include the steps of advancing the drawbar a gradually greater distance to insert the deformable blank through the gap between the main rolls before successive passes therethrough, and controlling the movement of one of the rolls in accordance with the distance by which said drawbar has been advanced as the blank is drawn through the roll gap.

According to another aspect of the invention, apparatus for the taper-rolling of metal includes a pair of main rolls, a drawbar for drawing a deformable blank between said main rolls, means for controlling the position of one of the rolls in accordance with the linear movement of said drawbar, and a pair of auxiliary rolls for bringing said deformable blank to a width somewhat less than the required final width before a final pass is effected between said main rolls. The main rolls and said auxiliary rolls are preferably freely rotatable. Preferably also, the means for controlling the position of said one of the main rolls in accordance with the linear movement of the drawbar will include a template. Said template will preferably move relative to a stylus when the drawbar is moved, said stylus preferably being carried by a profile head which moves in sympathy with said one roll. The profile head preferably includes a transducer which gives a mechanical feed back signal to an electro/hydraulic servo valve. The means for controlling the position of said one of the main rolls in accordance with the linear movement of the drawbar preferably also includes a hydraulic ram connected to a wedge arrangement on which said roll is supported. The wedge arrangement preferably includes a pair of wedges connected together in line for simultaneous movement and engaging complementary surfaces beneath respective roll chocks for said one roll. The hydraulic ram connected to the wedge arrangement is preferably trunnion mounted. The template is preferably a full sized facsimile of the tapered product or of a tapered part of the required product, and may be directly connected to the drawbar for movement in sympathy with it. The drawbar for drawing a deformable blank between the main rolls will preferably be provided with means for gripping an end of a blank, said means including a pair of jaws one of which is fixed relative to the drawbar and the other of which is movable under the control of a hydraulic ram. Wedge means are preferably provided for imparting the clamping forceto the movable jaw from the hydraulic ram. The movable jaw will preferably be connected to a body part of the gripping means by a link to ensure that clamping pressure is applied to the blank in a direction normal to its clamped surface. The body part of the gripping means is preferably trunnion mounted in a carriage mounted in longitudinal guides for reciprocation towards or away from the rolls; in this way the deformable blank is not subjected to bending moments as it is drawn between the rolls. The carriage is preferably connected to a yoke to which a hydraulic ram for moving the drawbar is connected. The connection between the carriage and the yoke will preferably be adjustable to compensate for different lengths of rolled product and may be constituted by a pair of screwthreaded rods preferably arranged in a plane containing the axis of the hydraulic ram and the axis of the trunnions about which the body part of the gripping means can adjust itself relative to the carriage. Means are preferably provided for laterally adjusting the drawbar so that selected portions of the main rolls can be employed; said means may take the form of a screwthreaded adjustment for locating a framework carrying the longitudinal guides and the hydraulic ram for moving the drawbar.

The auxiliary rolls will preferably be disposed in parallel planes equally spaced at opposite sides of a pass line between the main rolls and perpendicular to a plane containing said main rolls. Said auxiliary rolls will preferably be carried by pivotally mounted levers so that they can be brought to their operative positions from retracted inoperative positions. Means forbringing said auxiliary rolls to their operative positions will preferably include a single hydraulic ram and may also include wedge means capable of being brought to bear between ends of the pivotally mounted levers remote from the auxiliary rolls. Adjustment means will preferably be provided for adjusting the spacing between the auxiliary rolls when in their operative positions, said adjustment means conveniently taking the form of a screwthreaded adjustment for adjusting the travel of the wedge means into engagement between the ends of the pivotally mounted levers.

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:

FIG. 1 is a diagrammatic view of apparatus for the taper rolling of metal, in this case a single taper leaf spring,

FIG. 2 is a diagrammatic view of control gear for controlling the position of a drawbar forming part of the apparatus,

FIG. 3 is a side view of the apparatus,

FIG. 4 is a plan view thereof,

FIG. 5 is a sectional view on the line 55 in FIG. 3,

FIG. 6 is a part-sectional detail view drawn to a somewhat larger scale than FIGS. 3 to 5,

FIG. 7 is a schematic view on the line 77 in FIG.

FIG. 8 is a side view of further mechanism which will presently be referred to,

FIG. 9 is a plan view thereof, and

FIG. 10 is a view in the direction of arrow 10 in FIG. 8.

Referring now to FIG. 1 of the drawings, 10 is a drawbar unit to which a heated blank can be connected by means generally indicated 12. A pair of freely rotatable rolls 14 and 16 define a roll gap 18 between which the heated blank can be passed by the drawbar. The drawbar is moved linearly by a hydraulic ram 20.

Means for controlling the position of one of the rolls, the lower roll 16, in accordance with the linear move ment of the drawbar includes a template 22 connected to the drawbar for movement in sympathy with it. The template is a full sized facsimile of the required spring profile or more correctly of one half of said spring. A profile head 24 is carried by structure in which the lower roll 16 is mounted, for vertical movements in sympathy therewith. Said profile head includes a transducer 26 having a stylus 28 which bears against the template, and is electrically connected to signal amplifying and direction sensing means generally indicated 30 for controlling a hydraulic ram 32 capable of moving said lower roll either upwardly or downwardly as required by wedge means generally indicated 34.

Means for controlling the position of the other of said rolls, the upper roll 12, include so-called screw-down mechanism (not shown) which may be manually operated.

Means for automatically controlling the position of the drawbar unit 10 on the initiation of a rolling operation are illustrated diagrammatically in FIG. 2 and include a pulse generator indicated 36 (driven by rack and pinion means 39, see FIG. 1), direction sensing means 38,

control gates

40 and 42, a counter 44 and a programme card 26 which determines the degree of infeed of the deformable blank before each working stroke. That is to say, a complete reduction cycle is divided into a certain number of working strokes, for example three or four working strokes, and these are of gradually increasing length as the completed spring half takes shape. In other words, during a complete reduction cycle, the hydraulic ram 20 for moving the drawbar linearly is under the control of the means illustrated in FIG. 2 and according to a particular programme set out on the programme card (in whatever form that might take for example the card may be a punched card and it is of course used in conjunction with the necessary apparatus for translating the instructions it contains). The lower roll is controlled by positioning an electro/hydraulic servo valve with a fixed pass reference signal and a transducer which gives a mechanical feedback position. In the DRAW" position on the first pass (i.e. the lower roll being fully down and the heated blank being in position for a first reduction to commence as shown in FIG. 1) the transducer will home about a position x. Similarly for passes two and three the transducer will home about positions (x l) and (x 2) respectively, these positions being predetermined by the programme card.

The means 12 for connecting a heated blank to the drawbar unit are constituted by gripping means shown in detail in FIG. 6 and including a pair of jaws 46 and 48. The jaw 46 is fixed relative to a body part 50 of the gripping means but the jaw 48 is pivotally connected thereto by means of a link 52. Wedge means, constituted by a wedge 54 which bears against an abutment surface 56 formed on said body part, are provided for imparting a clamping force to the movable jaw. A hydraulic ram 58 is provided for moving the wedge, the cylinder 60 of said ram being pivotally connected at one end between a pair of walls 62 forming part of said body part and the piston rod 61 of said ram being pivotally connected to the wedge. The arrangement is such that clamping pressure is applied to the blank in a direction normal to its clamped surface.

The body part 50 of the gripping means is trunnion mounted in a carriage 64 which is mounted in longitudinal guides 66 for reciprocation towards or away from the rolls. Consequently the heated blank is not subjected to bending moments as it is drawn between the rolls. As best seen in FIG. 4, the carriage 64 is connected to a yoke 66 to which the hydraulic ram 20 is connected; the connection between the carriage and the yoke is constituted by a pair of screw-threaded rods 68 arranged in a plane containing the axis of the hydraulic ram and the axis of the trunnions 70 about which the body part of the gripping means can adjust itself relative to the carriage. By virtue of this arrangement, the distance between the carriage 64 and yoke 66 can readily be adjusted to compensate for differences in the lengths of the rolled product.

Means are provided for laterally adjusting the drawbar and associated structure relative to the rolls so that selected portions of the rolls can be employed. These means are constituted by a screwthreaded shaft which is axially fixed relative to a fixed frame part of the apparatus, the screwthreaded shaft having threaded engagement with a nut 82 fixed in a depending part of framework carrying the longitudinal guides and the hydraulic ram 20. In this way, rolls of extended length, i.e. of a greater length than would seem necessary, can be employed so that they will give long service before requiring replacement when badly worn.

The wedge means 34 previously referred to for moving the lower roll, either upwardly or downwardly as required, under the control of the hydraulic ram 32, include a pair of wedges 72 connected together in line, as shown in FIG. 7, for simultaneous movement. The cylinder of the hydraulic ram is trunnion mounted as shown and its piston rod is pivotally connected to the adjacent wedge. The wedges engage complementary surfaces 74 of a mounting 76 beneath respective roll chocks 78 for the lower roll. By this arrangement the lower roll is given maximum stability and remains truly horizontal throughout its vertical adjustment.

Referring now to FIGS. 8 to 10, a pair of freely rotatable auxiliary rolls 84 are provided at the draw bar side of the main rolls l4 and 16, said auxiliary rolls being disposed in parallel planes equally spaced at opposite sides of the pass line between said main rolls and perpendicular to a plane containing said main rolls, and being carried at the forward ends of respective levers 86.

The levers 86 are pivotally mounted intermediate their ends about respective pivots 88 upstanding from fixed structure 90 and means generally indicated 92 are provided for bringing the auxiliary rolls to operative positions from retracted inoperative positions, said means being constituted by wedge means capable of being brought to bear between ends of the pivotally mounted levers remote from the auxiliary rolls. Said wedge means include a wedge element 94 pivotally mounted intermediate its ends at 96'on the fixed structure and connected at one end to a piston rod 98 of a hydraulic ram 100 which is trunnion mounted at 102 beneath said fixed structure. A free end of said wedge element is provided with an arcuate part 104 of wedge form which can be brought into engagement with taper blocks 106 which are carried at the ends of the levers 86. A screwthreaded adjustment is provided for adjusting the travel of the wedge element into engagement between the taper blocks at the ends of the levers and thus for adjusting the spacing between the auxiliary rolls when in their operative positions.

The operating cycle of the apparatus is as follows:

1. The upper roll 14 is adjusted to a pre-determined position.

2. The drawbar is advanced a predetermined distance according to information supplied by the programme card to insert the deformable blank the required distance between the main rolls.

3. The drawbar is retracted to draw the blank through the roll gap. As it does so, the lower roll moves under the control of the hydraulic ram 32 according to that part of the template profile corresponding to the distance by which the blank has been inserted between the main rolls.

4.. When the drawbar has been fully retracted, the sequence is initiated once more and the drawbar is again advanced a further distance than before to insert the blank a further distance between the main rolls prior to being drawn through the roll gap as the lower roll again moves under the control of the hydraulic ram 32, in accordance with the template profile. Successive working strokes are carried out in this way until the deformable blank has been brought almost to the required final taper form.

5. At this stage the auxiliary rolls are brought to their operative positions by the operation of the hydraulic ram 100 and the deformable blank is drawn between them to reduce it in width to bring it to a width somewhat less than the required final width.

6. The auxiliary rolls are then retracted once again and the deformable blank is fully inserted between the main rolls.

7. The drawbar is retracted to draw the blank through the roll gap as the lower roll moves under the control of the hydraulic ram 32 according to the full length of the template profile. As it does so, the blank returns to its required final width as it is brought to the required final taper form.

Since reductions are effected by drawing the blank through the roll gap, the tendency for the metal to spread laterally is considerably reduced but not entirely eliminated. The method of rolling hereinbefore described has been found to completely overcome this problem however.

The amount by which it is necessary to reduce the width of the deformable blank below the required final width by the auxiliary rolls will depend upon the cross sectional proportions of the rolled product being produced and on the degree of reduction which is to be made during the final pass between the main rolls. However, it has been found generally appropriate to reduce the width of the blank to bring it to a width approximately 5 percent below the required final width. It will also be understood that since the shape of the tinished product is determined according to the shape of a template, the apparatus can very easily be set up for producing products of different shapes, that is to say of differing degrees of taper for example, by changing the template, and if such a change requires a corresponding change in the degree of width reduction below the required final width this can easily be effected by means of the screwthreaded adjustment provided.

Various modifications may be made without departing from the scope of the invention. For example, the hydraulic rams for moving the drawbar and for operating the wedge means 34 could be replaced by electric motors and suitable gearing. Furthermore, the template need not necessarily be made of metal. For example, for relatively short production runs it could be made of a plastics material; it will probably be convenient to make the plate a full sized facsimile of the tapered product required but of course this is not essential. For example, it could be arranged for the template to be twice full size (the apparatus being modified to take account of this of course) or of any other scale required. It is also a simple matter to vary the rolling programme appropriately by inserting a different programme card.

It will also be understood that the auxiliary rolls need not necessarily be arranged as shown in the drawing, for example, it would not be outside the scope of the invention for the auxiliary rolls to be mounted for rotation about axes parallel to the main rolls which would of course involve the deformable blank being turned through a right angle before and after the auxiliary rolls were used. Furthermore, the auxiliary rolls need not be carried by pivotally mounted levers; they could for example be carried by mounting brackets slidable in guides into or from operative positions.

The wedge means which are provided for bringing the auxiliary rolls to their operative positions from their retracted inoperative positions need not be as illustrated in the drawings, and in fact may be more in the nature of cam means so that the pressures exerted by the deformable blank against the auxiliary rolls do not tend to force the taper blocks down the surfaces of the wedge element. In other words, the wider end of the wedge element may have a parallel portion onto which follower means at the ends of the levers 86 remote from the auxiliary rolls can be brought to bear. More than one such parallel portion could be provided and having different widths could be arranged to bring the auxiliary rolls to different width settings required. Furthermore, means could be provided for adjusting the spacing of the auxiliary rolls as a deformable blank passes between them so that they compensate for the fact that since the deformable blank is being brought to a taper form the degree of spread which has made it difficult to control the width of the rolled product is not constant along the length of the product but is greatest where the degree of reduction is greatest. Such means could be mechanical means for controlling the wedge or cam means referred to above or may be similar to the means for controlling the roll gap between the main rolls, that is to say including a template and a hydraulic ram controlled in accordance with the profile of the template.

What I claim is:

1. A method for the taper-rolling of metal including the steps of drawing a deformable blank between a pair of rolls and simultaneously controlling the position of at least one of said rolls in accordance with the linear movement of a drawbar for drawing said blank between the rolls, the deformable blank being drawn between the said rolls a number of times to reduce it to the required form, and before a final pass is effected the blank is reduced in width between a pair of auxiliary rolls to bring it to a width somewhat less than the required final width so that during the final pass between the first mentioned pair of rolls, that is to say the main rolls, the blank returns to said required final width as it is brought to the required final taper form.

2. The method according to claim 1, including the steps of advancing the drawbar a gradually greater distance to insert the deformable blank through the gap between the main rolls before successive passes therethrough, and controlling the movement of one of the rolls in accordance with the distance by which said drawbar has been advanced as the blank is drawn through the roll gap.

3. Apparatus for the taper-rolling of metal, the apparatus including a pair of main rolls, a drawbar for drawing a deformable blank between said main rolls, means for controlling the position of one of the rolls in accordance with the linear movement of said drawbar, and a pair of auxiliary rolls for bringing said deformable blank to a width somewhat less than the required final width before a final pass is effected between said main rolls.

4. Apparatus according to claim 3, in which the main rolls and said auxiliary rolls are freely rotatable.

5. Apparatus according to claim 3, in which means for controlling the position of said one of the main rolls in accordance with the linear movement of the drawbar includes a template.

6. Apparatus according to claim 5, in which means for controlling the position of said one of the main rolls in accordance with the linear movement of the drawbar also includes a hydraulic ram connected to a wedge arrangement on which said roll is supported.

7. Apparatus according to claim 3, in which means are provided for laterally adjusting the drawbar so that selected portions of the main rolls can be employed.

8. Apparatus according to claim 3, in which the auxiliary rolls are carried by pivotally mounted levers so that they can be brought to their operative positions from retracted inoperative positions.

9. Apparatus according to claim 8, in which means for bringing said auxiliary rolls to their operative positions include a single hydraulic ram and also include wedge means capable of being brought to bear between ends of the pivotally mounted levers remote from the auxiliary rolls.

10. Apparatus according to claim 9, in which adjustment means are provided for adjusting the spacing between the auxiliary rolls when in their operative positions, said adjustment means taking the form of a screwthreaded adjustment for adjusting the travel of the wedge means into engagement between the ends of the pivotally mounted levers.

Claims

1. A method for the taper-rolling of metal including the steps of drawing a deformable blank between a pair of rolls and simultaneously controlling the position of at least one of said rolls in accordance with the linear movement of a drawbar for drawing said blank between the rolls, the deformable blank being drawn between the said rolls a number of times to reduce it to the required form, and before a final ''pass'' is effected the blank is reduced in width between a pair of auxiliary rolls to bring it to a width somewhat less than the required final width so that during the final ''pass'' between the first mentioned pair of rolls, that is to say the main rolls, the blank returns to said required final width as it is brought to the required final taper form.

2. The method according to claim 1, including the steps of advancing the drawbar a gradually greater distance to insert the deformable blank through the gap between the main rolls before successive ''passes'' therethrough, and controlling the movement of one of the rolls in accordance with the distance by which said drawbar has been advanced as the blank is drawn through the roll gap.

3. Apparatus for the taper-rolling of metal, the apparatus including a pair of main rolls, a drawbar for drawing a deformable blank between said main rolls, means for controlling the position of one of the rolls in accordance with the linear movement of said drawbar, and a pair of auxiliary rolls for bringing said deformable blank to a width somewhat less than the required final width before a final ''pass'' is effected between said main rolls.