US20030097868A1

US20030097868A1 - Sheet metal follower associated with a press for bending sheet metal

Info

Publication number: US20030097868A1
Application number: US10/036,411
Authority: US
Inventors: Morikatsu Matsuda; Gerard Quesnel
Original assignee: Amada Europe SA
Current assignee: Amada Europe SA
Priority date: 2001-01-08
Filing date: 2002-01-07
Publication date: 2003-05-29
Also published as: EP1221348A1; FR2819202B1; FR2819202A1; DE60117510T2; DE60117510D1; JP2002248521A; EP1221348B1

Abstract

A sheet metal follower associated with a press for bending a metal sheet, the follower being of the type comprising a pivot mechanism capable of causing the follower table to tilt, wherein a toothed wheel that is prevented from rotating is connected to a second toothed wheel by a cog belt, wherein the second toothed wheel pivots inside the cog belt, thereby causing the follower table to pivot about the rotary shaft, and wherein the upward and downward movements of the follower table are synchronized with its pivoting movement so that the plane in which the top support face of said table lies always includes the front edge of the matrix of the bending press.

Description

FIELD OF THE INVENTION

The present invention relates to a sheet metal follower associated with a press for bending a metal sheet, the follower being of the type comprising a gap frame, a stationary bottom table carrying a horizontal matrix of triangular section and a vertically moving top table carrying a bending punch, the sheet metal follower comprising:

a vertical base plate guided horizontally along the bottom table of the bending press;

a sliding support mounted to slide vertically on at least one vertical rail of the base plate;

a vertical drive mechanism comprising a wormscrew and a nut, the vertical nut co-operating with a first servo-motor and meshing with tapping of the nut fixed to the sliding support;

a follower table hinged so as to be capable of tilting about a horizontal shaft; and

a pivot mechanism mounted on the sliding support and capable of causing the follower table to tilt synchronously with the vertical movement of the sliding support so that the plane in which the top face of said follower table lies contains the front top edge of the matrix, said mechanism presenting:

a pivot shaft pivoted by means of a second servo-motor and gearing mounted on the sliding support;

a pivot arm having one end keyed to the pivot shaft and having its other end carrying a rotary shaft mounted to rotate freely;

at least one first toothed wheel mounted on the pivot shaft in such a manner as to be capable of remaining stationary while said shaft pivots;

at least one second toothed wheel secured to the rotary shaft and co-operating with said first toothed wheel; and

at least one connection arm secured to the second toothed wheel and to the follower table.

BACKGROUND OF THE INVENTION

That type of follower constitutes the subject matter of unpublished Japanese application No. 11-199185 of Jul. 13, 1999 and presents a certain number of drawbacks, due in particular to using a large number of toothed wheels or gearwheels. In spite of the particular care taken when milling the teeth, it is inevitable that a small amount of slack will always exist between two toothed wheels that mesh one in the other, said slack increasing as the sheet metal follower continues to be used.

OBJECT AND SUMMARY OF THE INVENTION

The object of the present invention is to propose means enabling the above-mentioned drawbacks to be attenuated or even eliminated.

In a first solution to this problem, which applies more particularly to metal sheets of a weight that does not exceed 80 kilograms (kg), the invention proposes that the first toothed wheel which is prevented from rotating is connected to the second toothed wheel by a cog belt snugly engaging the teeth of the first and second toothed wheels, that the second toothed wheel turns, pivoting inside the cog belt under the action of the pivot arm moving the rotary shaft and the second toothed wheel along a circular arc, that the pivoting movement of the second toothed wheel secured to the follower table causes said table to pivot about the rotary shaft, and that the upward and downward movements of the follower table are synchronized with the pivoting movements thereof such that the plane in which the top support surface of said table lies always contains the front edge of the matrix of the bending press.

By means of this disposition, a large number of toothed wheels are eliminated each constituting a source of slack and a lack of precision between its teeth, and the structure of the pivot mechanism is greatly simplified.

When the follower table is to support thick metal sheets, in particular heavy sheets weighing about 100 kg or more, the reaction force of said table runs the risk of stretching the cog belt and leading to inaccurate positioning of the table and the metal sheet resting thereon.

To eliminate that drawback, it would be possible to use a transmission using toothed wheels and link chains of the bicycle type, for example. However, under those circumstances there always remains slack between a pair of teeth and the transverse rollers interconnecting the side plates of links in the chain.

To eliminate that drawback, the invention proposes that the pivot shaft is supported in two bearings each mounted in a lateral support arm secured to the top portion of one or other of the vertical edges of the sliding support and directed towards the follower table, that the pivot shaft carries on either side of the pivot arm a first toothed wheel mounted rotate freely relative to the pivot arm, that on either side of the front end of the pivot arm situated adjacent to the follower table the rotary shaft is secured to a second toothed wheel coplanar with the corresponding first toothed wheel, that each second toothed wheel is fixed on a radial connection arm provided at the rear end of the follower table, that first and second roller chains or the like pass around respective pairs of coplanar first and second toothed wheels, and that each first toothed wheel is associated with tensioning and repulsion means, where those associated with the first toothed wheel co-operating with the first chain act on the top strand of said chain in a first direction corresponding to the clockwise direction such that the rollers of the first chain bear against the rear flanks of the teeth of the corresponding first toothed wheel, and where those means associated with the other first toothed wheel co-operating with the second chain act on the bottom strand thereof in a direction corresponding to the counterclockwise direction so that the rollers of the second chain are pressed against the other flanks of the teeth of the corresponding other first toothed wheel.

This ensures that the follower table moves to follow and position accurately without tilting while avoiding any shaking due to slack of the gears. In addition, the follower table moves without making significant noise.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention will appear from the following description of two embodiments. [0020]
The description is made with reference to the accompanying drawings, in which: [0021]
FIG. 1 is a diagrammatic side view in elevation of a first embodiment of the sheet metal follower, and in particular of its pivot mechanism; [0022]
FIG. 2 is a diagrammatic perspective view of a second embodiment of the pivot mechanism of the sheet metal follower; [0023]
FIG. 3 is a diagrammatic plan view of the second embodiment; [0024]
FIG. 4 is a detail plan view of the rear portion of the second embodiment as shown in FIG. 3; [0025]
FIG. 5 is a more detailed diagram of the tensioning and repulsion means associated with one of the first toothed wheels; [0026]
FIG. 6 is a detail plan view of the second embodiment of the pivot mechanism; [0027]
FIG. 7 is a diagrammatic plan view of an follower table in which the sheet metal follower is provided with a support for a removable extension; [0028]
FIG. 8 is a perspective view of the FIG. 7 extension support; and [0029]
FIG. 9 is a diagrammatic side view in elevation and in section of the follower table on IX-IX of FIG. 7.[0030]

MORE DETAILED DESCRIPTION

As can be seen more particularly in FIG. 1, the sheet metal follower comprises a follower table [0031] 1 for accompanying a metal sheet 2 to be bent and associated with a conventional bending press 3 of the type comprising a gap frame (not shown), a stationary bottom table 4 carrying a horizontal matrix 5 of triangular cross-section, and a vertically movable top table 6 carrying a bending punch 7 for thrusting a portion of the metal sheet 2 into the matrix 5.
The sheet metal follower comprises a [0032] base plate 8 which extends substantially vertically and which is mounted on the front face of the stationary bottom table 4 via a pair of horizontal rails 9 provided on the front face of the stationary bottom table 4 and along which said base plate 8 is guided and movable horizontally.
The sheet metal follower also comprises a vertically [0033] slidable support 10 which is guided on at least one, and preferably on two, vertical rails 11 provided on the base plate 8 and penetrating into corresponding grooves 12 in two lateral vertical guides 13 secured to the rear face of the sliding support 10, and a vertical drive mechanism 14 for moving the sliding support 10. This drive mechanism 14 is of the type comprising a wormscrew and a nut, and it presents a first servo-motor 15 whose casing is secured to the base plate 8 and which drives the vertical wormscrew 18 of the drive mechanism 14, e.g. via two gearwheels 16, 17, this vertical screw being held in bearings (not shown) secured to the base plate 8 and meshing in the tapping of a nut 19 secured to the rear face of the sliding support 10. Thus, when the first servo-motor 15 turns in either direction the vertical screw 18 turns in corresponding manner and the nut 19 together with the sliding support 10 moves up or down depending on the direction of rotation of said endless screw 18.
The sheet metal follower also comprises a [0034] pivot mechanism 20 which is mounted on the sliding support 10 and capable of causing the follower table 1 proper to tilt or pivot synchronously with the vertical movement of the sliding support 10 so that the bearing top face of the follower table 1 lies in a plane 21 that substantially intersects the front top edge 5 a of the matrix 5 during an operation of bending the metal sheet 2.
To understand how the [0035] pivot mechanism 20 operates, it is appropriate to refer to FIGS. 1 to 6 together even though there are certain differences between the first and second embodiments.
The [0036] pivot mechanism 20 comprises at least one and preferably two support arms 22 secured to the front face of the top portion of the sliding support 10. When there are two support arms 22, each of them is secured to one or other vertical edge of the sliding support 10 and is directed forwards from the front face thereof perpendicularly relative to said front face. A pivot arm 23 is received in a bearing 24 of each lateral support arm 22 and carries a gearwheel 25 at one of its free ends which is keyed to said shaft 23 and which meshes with a gearwheel 26 constraints to rotate with the outlet shaft of a second servo-motor 27 whose casing is mounted on the sliding support 10. A pivot arm 28 is keyed at its rear end to the pivot shaft 23 and at its other or front end carries a rotary shaft 29 mounted to rotate freely in a ball bearing 30 provided in the said front end of said rotary shaft 29.
Between a [0037] support arm 22 and the rear end of the pivot arm 28, and close to said support arm 22, there is mounted a “first” toothed wheel 31 on the pivot shaft 23, and said shaft 23 can turn freely relative thereto by means of a bearing, e.g. of the ball bearing type 32 interposed between the shaft 23 and the hub of the first toothed wheel 31. As can be seen in FIGS. 2, 3, and 6, another first toothed wheel 31 is provided on the pivot shaft 23 between the other support arm and the pivot arm 28.
In a embodiment (see FIG. 1), the first [0038] toothed wheel 31 is prevented from rotating and is preferably locked to the adjacent support arm 22. Depending on requirements, it can have one or two support arms 22, one or two first toothed wheels 31, one or two second toothed wheels 33, and the corresponding bearings 24, 30, and 32.
As already mentioned, the front end of the [0039] pivot arm 28 has a rotary shaft 29 turning freely in a ball bearing type bearing 30 mounted in a suitable housing at the front end of said pivot arm 28. Outside the pivot arm 28, the rotary shaft 29 is provided with at least one second toothed wheel 33 keyed onto said shaft 29 in a position where it is coplanar with a corresponding first toothed wheel 31. In a preferred embodiment, the rotary shaft 29 is provided with two second toothed wheels on either side of the pivot arm. A connection arm 34 extending preferably in a diametral plane of the second toothed wheel 33 is fixed by means of bolts 35 thereto and is also secured to the follower table 1.
In a first embodiment, which applies to metal sheets of weight not exceeding about 80 kg, the first [0040] toothed wheel 31 is connected to the second toothed wheel 33 by a cog belt 36 whose cogs engage snugly in the gaps between successive teeth in the first and second toothed wheels 31 and 33 that are coplanar (see FIG. 1). When there are two first toothed wheels 31 and two second toothed wheels 33, there are also two cog belts 36, with each first toothed wheel 31 being coplanar with a corresponding second toothed wheel.
Operation is as follows: during a bending operation, the first servo-[0041] motor 15 drives the sliding support 10 upwards to a level where the support face of the table 1 is at the same height as the edge 5 a of the matrix 5, said table then being substantially horizontal. As soon as the second servo-motor 27 is set into operation, the pivot arm 28 pivots about the axis of the shaft 23 to which it is secured and moves the rotary shaft 29 upwards together with the second toothed wheel 33 along a circular arc centered on the shaft 23. Since the first toothed wheel 31 does not turn, the strands of the cog belt 36 cannot move in the longitudinal direction. Consequently, in order to enable the arm 28 and the second toothed wheel 33 to pivot upwards, the toothed wheel turns inside the cog belt 36 in a counterclockwise direction (as represented by curved arrow 37 in FIG. 1). As a result, while the second toothed wheel 33 is rising, the free end of the table 1 tilts slightly downwards (see FIG. 1, curved arrow 38) during the generally upward movement of the table along curved arrow 39. It is by means of this disposition that it is possible to correct the inclination and the position of the support face of the table 1 so that the plane 21 in which this support face lies always substantially contains the edge 5 a of the matrix 5 during an operation of bending a metal sheet 2.
When the weight of the sheet to be supported by the follower table [0042] 1 is greater than about 80 kg, it is preferable to use at least one, and preferably two, chains 40 of roller or any other suitable type in combination with tensioning and damping means 41 which press against or push each transverse roller 42 or the like of the chain 40 so that it presses against the flank 31 a of a corresponding tooth 31 b of the first toothed wheel 31, so that the top strand 43 of the chain 40, 40 a is always under tension and so that its transverse rollers 42 are always pressed against the flanks 31 a of the corresponding teeth 31 b when said rollers 42 are received in the gaps between the flanks of two adjacent teeth 31 b.
Given that the follower table [0043] 1 must be capable of pivoting not only upwards but also downwards, the tensioning and repulsion means 31 associated with a first chain 40 a are arranged in such a manner that the top strand 43 of said first chain 40 a is tensioned in the direction of arrow 44 towards the sliding support 10 and the tensioning and repulsion means 41 associated with the second chain 40 b which is parallel to the first chain (40 a) are arranged in such a manner that the bottom strand 45 of the second chain 40 b is tensioned in the direction of arrow 45 towards the sliding support 10. Under such circumstances, the rollers 42 of the bottom strand 45 of the second chain 40 b are pressed against the opposite flanks 31 c of each tooth 31 b of the toothed wheel 31 engaged with the second chain 40 b.
The tensioning and repulsion means [0044] 41 in each of the stationary first toothed wheels 31 comprise at least one oblong slot 47 extending circumferentially and presenting a section that can be rectangular, annular, etc. in shape, for example, and preferably, a plurality of such slots 47 a, 47 b, 47 c, and 47 d provided in the body of each first toothed wheel 31 and distributed uniformly around the cylindrical passage for the pivot arm 23, a thrust peg 48 fixed in a transverse housing 49 of a support arm 22 and extending transversely and parallel to the pivot arm 23 so as to penetrate at its free end into one of the oblong slots 47 a to 47 d of the first toothed wheel 31, and a compression spring 50 disposed in the corresponding oblong slot (e.g. 47 a) and interposed between an end face of the slot (e.g. 47 a) and the peg 48 so as to bear firstly against an end face of said slot and secondly against the free end of the peg 48 received in said oblong slot, said peg having its side face bearing against the other end of said slot under the drive of the compression spring 50.
It will be observed that depending on the location of the [0045] compression spring 50 relative to the bearing peg 48, the first toothed wheel 31 is urged either clockwise or else counterclockwise (see FIG. 2).
In FIG. 5, it can clearly be seen how the [0046] pegs 48 and the compression springs 50 mounted in the slots 47 a to 47 d of the first toothed wheel 31 are disposed relative to one another for the purpose of subjecting the top strand 43 of the chain 40, 40 a to a tension or traction force directed along arrow 44 towards the sliding support 10, or in other words clockwise (see arrow 51).
In this case, each of the [0047] slots 47 a to 47 d receives a compression spring 50 which, relative to the direction of arrow 51, bears firstly against the front end of the corresponding slot (47 a to 47 d) and secondly against the front side face of the corresponding peg 48, thereby urging the rear end of the slot against the rear side face of the peg in question.
When the relative disposition of the [0048] spring 50 and the peg 48 is the other way round in each slot 47 or 47 a to 47 d, then the spring 50 urges the first toothed wheel 31 in the counterclockwise direction (see arrow 52 in FIG. 2) so that the bottom strand 45 of the chain 40, 40 b is urged in the same direction (see arrow 46) towards the sliding support 10. This avoids the table 1 performing any jerky movements, both when rising and when descending. It is also possible to arrange the slots 47, 47 a to 47 d in each support arm 22 and to fix the pegs 48 on each of the first toothed wheels 31, with the free ends of the pegs 47 and the compression spring 50 then being housed in the slots 47, 47 a to 47 d in each support arm 22.
The sheet metal follower is, in general, relatively narrow compared with the width of the [0049] bending press 3. As a result, it is necessary to have two or even more additional sheet metal followers when it is necessary to bend metal sheet of great width so as to ensure that the sheet does not droop or sag laterally under the effect of the weight of its portions that are not supported.
The present invention proposes a simple solution that enables additional followers to be omitted by replacing them with a support extension that is mounted removably on the top end of the follower table [0050] 1.
As can be seen more clearly in FIGS. 7 and 9, the table [0051] 1 has a transverse recess 55 fitted with an intermediate fixing plate 56 and where appropriate a fixed jaw 57 and two side jaws 58 sliding on the bottom 59 of the recess 55, if necessary under drive from controlling actuators 60. The rear face of the recess 55 is defined by an abutment block 61 which can be used as a fixed jaw when the two moving jaws 58 are urged towards the rear of said table 1.
The [0052] extension support 62 is generally H-shaped and comprises a crossbar 63 parallel to the front face 64 of the bending press 0.3 and two side bars 65 that are perpendicular to said front face 64. The transverse length of the extension support 62 is sufficient to support the side extremities of the metal sheet 2 (as can be seen in FIG. 7) while nevertheless being slightly less than the working width of the bending press.
The [0053] crossbar 63 of the extension support 62 presents, in its center, a cylindrical hole 66 for passing a fixing bolt 67 whose threaded portion passes through an oblong slot (not shown) in the intermediate plate 56 and is screwed into a nut (not shown) that holds it against the bottom face of said plate 56. The oblong hole extends mainly perpendicularly to the front face 64 of the bending press 3. This makes it possible to adapt the positions of crossbars 63 of different widths. In addition, in order to be fixed to the intermediate plate 56 by means of the bolt 67, the crossbar 63 of the extension support 62 can be inserted between the fixed jaw 57 and the moving jaws 58, where appropriate.
To facilitate advancing the [0054] metal sheet 2, the top face of the extension support 62, i.e. the top faces of the crossbar 63 and of the side bars 64, and also the top face of the fixed jaw S7 and that of the abutment block 61 can be provided with ball bearings 69 that serve to support the metal sheet 2 for bending.
The subject matter of the present invention can be modified in various ways by the person skilled in the art without thereby going beyond the ambit of the protection defined by the accompanying claims. In particular, it should be observed that the drawings are diagrammatic only and do not show the exact dimensions of the various component elements of the sheet metal follower. [0055]

Claims

1/ A sheet metal follower associated with a press for bending a metal sheet, comprising a gap frame, a stationary bottom table carrying a horizontal matrix of triangular section having a front edge and a vertically moving top table carrying a bending punch, said sheet metal follower comprising:

a vertical base plate guided horizontally along said bottom table of the bending press, and provided with at least one vertical rail;

a sliding support mounted to slide vertically on said at least one vertical rail of the base plate;

a first servo-motor;

a vertical drive mechanism comprising a wormscrew and a nut, the vertical nut co-operating with said first servo-motor and meshing with tapping of the nut fixed to the sliding support;

a follower table having a top support surface, said table being hinged so as to be capable of tilting about a horizontal shaft; and

a pivot mechanism mounted on said sliding support and capable of causing the follower table to tilt synchronously with the vertical movement of the sliding support so that the plane in which the top face of said follower table lies contains the front top edge of the matrix, said pivot mechanism comprising:

a second servo-motor;

a pivot shaft pivoted by means of said second servo-motor and gearing mounted on the sliding support;

a pivot arm having a first end keyed to the pivot shaft and a second end;

a rotary shaft mounted on the second end of said pivot arm to rotate freely;

at least one first toothed wheel mounted on said pivot shaft in such a manner as to remain stationary while said shaft pivots;

at least one second toothed wheel secured to said rotary shaft and co-operating with said first toothed wheel;

at least one connection arm secured to said second toothed wheel and to said follower table; and

a cog belt ;

wherein said first toothed wheel is connected to said second toothed wheel by said cog belt snugly engaging the teeth of the first and second toothed wheels, wherein said second toothed wheel turns, pivoting inside said cog belt under the action of said pivot arm moving said rotary shaft and said second toothed wheel along a circular arc, wherein the pivoting movement of said second toothed wheel secured to said follower table causes said table to pivot about the rotary shaft, and wherein the upward and downward movements of said follower table are synchronized with the pivoting movements thereof such that the plane in which the top support surface of said follower table lies always contains the front edge of the matrix of the bending press.

2/ A sheet metal follower according to claim 1, wherein said pivot shaft is supported in two bearings each mounted in a lateral support arm secured to the top portion of one or other of the vertical edges of the sliding support and directed towards the follower table, wherein said pivot shaft carries on either side of said pivot arm one of said first toothed wheels mounted rotate freely relative to the pivot arm, wherein on either side of the front end of said pivot arm situated adjacent to the follower table said rotary shaft is secured to one of said second toothed wheels coplanar with said corresponding first toothed wheel, wherein each second toothed wheel is fixed on a radial connection arm provided at the rear end of said follower table; said follower table further comprising a cog belt to interconnect one of said first toothed wheels and said second toothed wheel that is coplanar with said one of said first toothed wheels.

3/ A sheet metal follower associated with a press for bending a metal sheet comprising a gap frame, a stationary bottom table carrying a horizontal matrix of triangular section and a vertically moving top table carrying a bending punch, said sheet metal follower comprising:

a vertical base plate guided horizontally along said bottom table of the bending pres, said plate being provided with at least one vertical rail;

a sliding support mounted to slide vertically on said at least one vertical rail and provided with two vertical edges, each edge having a top portion;

at least one connection arm secured to the second toothed wheel and to the follower table;

a lateral support arm secured to said top portion of one or other of the vertical edges of the sliding support and directed towards said follower table;

two bearings for supporting said pivot shaft, each bearing being mounted in said lateral support arm;

two first toothed wheels carried by said pivot shaft on either side of said pivot arm and mounted to rotate freely relative to said pivot arm;

two second toothed wheels, each second toothed wheel being coplanar with one of said first toothed wheels, said second toothed wheels being secured to said rotary shaft on either side of the front end of said pivot arm situated adjacent to said follower table;

two radial connection arms provided at the rear end of the follower table on which said second toothed wheels are fixed;

first and second roller chain means passing around respective pairs of said coplanar first and second toothed wheels;

wherein each first toothed wheel is associated with tensioning and repulsion means, where those associated with the first toothed wheel co-operating with the first chain act on the top strand of said chain in a first direction corresponding to the clockwise direction such that the rollers of the first chain means bear against the rear flanks of the teeth of the corresponding first toothed wheel, and where those means associated with the other first toothed wheel co-operating with said second chain act on the bottom strand thereof in a direction corresponding to the counterclockwise direction so that the rollers of the second chain means are pressed against the other flanks of the teeth of the corresponding other first toothed wheel.

4/ A sheet metal follower according to claim 3, wherein said tensioning and repulsion means comprise at least one oblong slot formed in the body of each first toothed wheel, at least one bearing peg fixed in a transverse housing of a support arm and having its free end penetrating in said slot, and a compression spring interposed in said slot between an end face thereof and the peg.

5/ A sheet metal follower according to claim 3, wherein said tensioning and repulsion means comprise at least one oblong slot formed in each support arm, at least one bearing peg fixed on each first toothed wheel and having its free end penetrating in said slot, and at least one compression spring interposed in said slot between an end face thereof and the peg.

6/ A sheet metal follower according to claim 4, wherein said tensioning and repulsion means comprise a plurality of slots formed in each of the first toothed wheels or in each of the support arms, a corresponding plurality of bearing pegs fixed in corresponding housings of each of the support arms or each of the first toothed wheels and having their free ends penetrating into corresponding slots, and a plurality of compression springs each interposed in a corresponding slot between an end face thereof and a peg.

7/ A sheet metal follower according to claim 6, wherein said slots and said transverse housings are uniformly distributed around said pivot shaft.

8/ A sheet metal follower according to claim 1, wherein said follower table is provided with an extender support removably mounted on the top end of said table.

9/ A sheet metal follower according to claim 8, wherein said extender support is generally H-shaped.

10/ A sheet metal follower according to claim 8, wherein said extender support comprises a crossbar parallel to the front face of the bending press and two side bars perpendicular to said front face, and wherein said follower table has a transverse recess provided with an intermediate fixing plate on which the crossbar of said extender support is mounted by means of a fixing bolt which passes through a hole in the crossbar, and in the oblong slot of said intermediate plate and is screwed into a nut that presses against the bottom face of said plate.

11/ A sheet metal follower according to claim 10, wherein said transverse recess further includes a fixed jaw, two moving jaws sliding on the bottom of the recess and a rear abutment block, and in addition to fixing on said intermediate plate, said crossbar of said extender support is clamped between said fixed jaw and said moving jaws.

12/ A sheet metal follower according to claim 8, wherein said top face of said extender support is provided with a ball bearing for supporting the metal sheet to be bent.