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Patent Searching and Data


Title:
MACHINING TOOL
Document Type and Number:
WIPO Patent Application WO/2018/115861
Kind Code:
A1
Abstract:
A machining tool is described comprising a drive stage (42) and a bending stage (44), the drive (stage 42) comprising a plurality of rollers (48) engageable with a workpiece, in use, the rollers (48) each having a respective axis of rotation (50), the axes of rotation (50) being substantially parallel to and offset from one another, at least one of the rollers (48) of the drive stage (42) being driven for rotation and having an outer periphery of a rubber or rubber like material, the bending stage (44) comprising at least one roller (48) having an axis of rotation (50) that is movable relative to the drive stage (44). A machining tool is also described which comprises a machine tool (12) and a feed device (14), the feed device (14) being attached to the machine tool (12) in an articulated manner, wherein the feed device (14) comprises a first roller (30a) and a second roller (30b), the first and second rollers (30a), (30b) being spaced apart from one another and adapted, in use, to have a workpiece (26) fed therebetween and to be engaged thereby, wherein at least the periphery of at least the first roller (30a) is of a rubber or rubber like material, and wherein the first roller (30a) is driven for rotation by a drive motor (32).

Inventors:
WHATTON, Rolly (Redbank, Ledbury Hereford and Worcester HR8 2JL, HR8 2JL, GB)
Application Number:
GB2017/053829
Publication Date:
June 28, 2018
Filing Date:
December 20, 2017
Export Citation:
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Assignee:
HAYGROVE LIMITED (Redbank, Ledbury, Hereford and Worcester HR8 2JL, HR8 2JL, GB)
International Classes:
B21D7/08; B21D7/024
Foreign References:
GB2165175A1986-04-09
US4440203A1984-04-03
JPH0658326A1994-03-01
DE2518798A11976-11-11
DE4210227A11993-09-30
EP2399688A12011-12-28
Attorney, Agent or Firm:
BAILEY, Richard Alan (HCR Patents, 142 Leckhampton Road, Cheltenham Gloucestershire GL53 0DH, GL53 0DH, GB)
Download PDF:
Claims:
CLAIMS:

1. A machining tool comprising a drive stage and a bending stage, the drive stage comprising a plurality of rollers engageable with a workpiece, in use, the rollers each having a respective axis of rotation, the axes of rotation being substantially parallel to and offset from one another, at least one of the rollers of the drive stage being driven for rotation and having an outer periphery of a rubber or rubber like material, the bending stage comprising at least one roller having an axis of rotation that is movable relative to the drive stage.

2. A tool according to Claim 1, wherein at least one of the rollers of the drive stage is movably mounted relative to at least one other of the rollers of the drive stage.

3. A tool according to Claim 2, wherein the said movably mounted roller is spring biased towards a position in which it engages the workpiece, in use.

4. A tool according to any of the preceding claims, wherein the bending stage further comprises a fixed roller.

5. A tool according to any of the preceding claims, wherein the said at least one movable roller of the bending stage is mounted upon a movable support.

6. A tool according to Claim 5, wherein the movable support is movable by an actuator.

7. A tool according to Claim 6, wherein the actuator is a hydraulic actuator.

8. A tool according to any of the preceding claims, wherein the tool further comprises a first switch or sensor actuable or operable by the presence of the workpiece at a first location and a second sensor switch actuable or operable by the presence of the workpiece at a second location.

9. A tool according to Claim 8, wherein the switches or sensors are used in controlling the operation of the tool.

10. A tool according to any of the preceding claims, wherein the tool is hydraulically or pneumatically driven and/or controlled.

11. A machining device comprising a machine tool and a drive stage, the drive stage being attached to the machine tool in an articulated manner, wherein the drive stage comprises a first roller and a second roller, the first and second rollers being spaced apart from one another and adapted, in use, to have a workpiece fed therebetween and to be engaged thereby, wherein at least the periphery of at least the first roller is of a rubber or rubber like material, and wherein the first roller is driven for rotation by a drive motor.

12. A device according to Claim 11, wherein the first and second rollers are both of rubber or rubber-like material, at least around the peripheries thereof.

13. A device according to Claim 11 or Claim 12, wherein the drive stage further comprises a third roller

14. A device according to Claim 13, wherein the third roller is of a rubber or rubber-like material around at least the periphery thereof.

15. A device according to any of Claims 11 to 14, wherein the second roller is driven for rotation.

16. A device according to Claim 15, wherein the speed of rotation of the driven rollers is controlled such that they are driven at the same rotary speed as one another.

17. A device according to any of Claims 11 to 16, wherein the machine tool comprises a ring roller.

18. A device according to Claim 17, wherein the operation of the drive motor is controlled to avoid slipping between a roller of the ring roller and the workpiece, in use.

19. A device according to any of Claims 11 to 18, wherein the drive stage is mounted upon an arm that is pivotally attached to the machine tool.

Description:
MACHINING TOOL

This invention relates to a machining tool. By way of example, the invention relates to a machining tool of the type in which a substantially straight length of a material can be bent to adopt a curved form. However, the invention is not restricted in this regard and may be applied to other types of machining tool. It may be applied to tools controlled manually and to, for example to CNC machine tools.

Where a length of material is to be bent to adopt a curved form, a ring roller tool may be used. Typically, such a tool includes a pair of fixed rollers of substantially the same diameter as one another, each of the fixed rollers being rotatable about its axis, the fixed rollers being spaced apart from one another with the axes of rotation thereof parallel to one another, and a movable roller located between the fixed rollers in the direction of movement of a workpiece through the tool, but offset therefrom, the movable roller being moveable in a direction towards and away from a notional line intersecting the axes of the fixed rollers. The axes of rotation of the fixed rollers are substantially parallel to the axis of rotation of the moveable roller.

In use, a workpiece to be machined is fed through the tool such that the two fixed rollers are located to one side of the workpiece and the movable roller is located to the other side of the workpiece. Provided the distance of the axis of the moveable roller from the aforementioned notional line is less than the sum of the radius of the fixed roller and the radius of one of the moveable rollers, the workpiece is forced to adopt a bent or curved form in order to pass through the tool. The engagement between the rollers and the workpiece thus causes a bend or curve to be formed in the workpiece. The radius of curvature of the bend or curve is selected by appropriate positioning of the moveable roller relative to the fixed rollers, a smaller radius of curvature being formed where the spacing between the movable roller and the aforementioned notional line is reduced.

Typically, one or more of the rollers is arranged to be driven for rotation by a drive motor such that the workpiece is positively driven through the tool. The rollers are usually of steel construction, and where the workpiece is also of metallic form, there is a risk of slipping occurring between the workpiece and the driven roller. The risk of such slipping is increased where the workpiece is wet, as may occur if the tool is used outdoors, or if the workpiece or rollers are oily. Where slipping occurs, the workpiece may be damaged, and the uniformity of the curve or bend formed therein may be unacceptable. In order to reduce the risk of such slipping and so reduce the risk of the production of an unacceptably poor quality product, the operator may manually force the workpiece through the tool, pushing or pulling on the workpiece, and so aiding the rotation of the roller in driving the workpiece through the tool. Whilst this may have the effect of reducing the risk of the production of unacceptably poor quality products, it carries the risk of injury to the operator as he will, as least some of the time, have his hands located in close proximity to the rollers, and in particular to the points at which the workpiece engages the rollers, and so there is a risk of his fingers becoming trapped between the workpiece and the rollers with the attendant risk of injury. Clearly, this is undesirable.

It is an object of the invention to provide a machine tool in which at least some of the disadvantages associated with known arrangements are overcome or are of reduced effect.

According to the present invention there is provided a machining tool comprising a drive stage and a bending stage, the drive stage comprising a plurality of rollers engageable with a workpiece, in use, the rollers each having a respective axis of rotation, the axes of rotation being substantially parallel to and offset from one another, at least one of the rollers of the drive stage being driven for rotation and having an outer periphery of a rubber or rubber like material, the bending stage comprising at least one roller having an axis of rotation that is movable relative to the drive stage.

It will be appreciated that in such an arrangement, adjustment of the position of the at least one roller of the bending stage can result in the workpiece becoming bent with a desired radius of curvature, the radius of curvature depending upon the position of the roller of the bending stage. Such an arrangement is advantageous in that drive stage, and in particular the roller(s) with a rubber or rubber like material outer periphery are better able to grip the workpiece with the result that the workpiece is better driven through the bending stage. As the workpiece is better driven, the operator need not manually feed the workpiece through the bending stage. The risk of injury is therefore reduced. Furthermore, the resulting improved consistency of operation results in the bent workpieces formed using the tool being of improved consistency or uniformity. Wastage may therefore be reduced.

At least one of the rollers of the drive stage is preferably movably mounted relative to at least one other of the rollers of the drive stage. Preferably, the said movably mounted roller is spring biased towards a position in which it engages the workpiece, in use. Driving contact with the workpiece can thus be maintained, in use.

The tool preferably further comprises a first switch or sensor actuable or operable by the presence of the workpiece at a first location and a second sensor switch actuable or operable by the presence of the workpiece at a second location. The switches or sensors are preferably used in controlling the operation of the tool, for example in controlling whether the drive stage is operating, and in controlling the location of the roller of the bending stage.

Additional switches or sensors may be provided.

The machining tool is preferably hydraulically or pneumatically driven. By way of example, it may be driven using a hydraulic or pneumatic output from a tractor or the like.

According to another aspect of the invention there is providing a machining device comprising a machine tool and a drive stage, the drive stage being attached to the machine tool in an articulated manner, wherein the drive stage comprises a first roller and a second roller, the first and second rollers being spaced apart from one another and adapted, in use, to have a workpiece fed therebetween and to be engaged thereby, wherein at least the periphery of at least the first roller is of a rubber or rubber like material, and wherein the first roller is driven for rotation by a drive motor.

It will be appreciated that the provision of a drive stage of the form outlined hereinbefore is advantageous in that coefficient of friction between the workpiece and the rubber or rubberlike material of the first roller is relatively high and so the likelihood of slipping therebetween is reduced. By reducing the risk of slipping, the workpiece can be fed through the machine tool in a more controlled fashion, thereby reducing the risk of formation of poor quality products, and avoiding the need for the operator to place his hands close to the machine tool, thereby reducing the risk of injury.

Preferably, the first and second rollers are both of rubber or rubber-like material, at least around the peripheries thereof.

The drive stage may further comprise a third roller, preferably also being of a rubber or rubberlike material around at least the periphery thereof.

The second and/or third rollers may further be driven for rotation. In such an arrangement, the speed of rotation of the driven rollers is preferably controlled such that they are driven at the same rotary speed as one another.

The machine tool conveniently comprises a ring roller.

The articulated attachment of the drive stage to the machine tool is advantageous in that it allows the drive stage to adopt a suitable position, taking into account the nature of the workpiece and settings of the machine tool. By way of example, where the machine tool is a ring roller, the position of the feed device will alter depending upon the radius of curvature of the bend or curve in the workpiece to which the ring roller has been set. In a simple embodiment, the drive stage may be mounted upon an arm that is pivotally attached to the machine tool.

The invention will further be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a diagram illustrating a machining tool in accordance with an embodiment of the invention;

Figure 2 is a diagram illustrating another embodiment of a machining device; and

Figure 3 is a view illustrating the device of Figure 2 in another configuration.

Referring firstly to Figure 1, a machining tool 40 is illustrated. The tool 40 is intended for use in forming bends in workpieces, and comprises a drive stage 42 and a bending stage 44. The tool 40 comprises a housing 46 within which a number of rollers 48 are supported for rotation. Suitable bearings (not shown) are provided to support each roller 48 to rotate about its respective axis of rotation 50.

The drive stage 42 includes first, second and third rollers 48a, 48b, 48c rotatable about axes 50a, 50b, 50c. The axes 50a, 50b, 50c are parallel to and offset from one another. The first roller 48a is or a rubber or rubber like material, or at least the outer periphery thereof is of such a material. The first roller 48a is driven for rotation by a hydraulic motor 52 powered, in use, from a hydraulic output from the tractor or the like. Rotary drive motion is transmitted from the motor 52 to the first roller 48a by, for example, a drive belt 54 or other suitable drive transmission. The second and/or third rollers 48b, 48c may, if desired, also having at least an outer peripheral surface of a rubber or rubber like material and may, if desired, be driven for rotation by the motor 52 or by separate drive means.

The first, second and third rollers 48a, 48b, 48c are positioned such that a first surface or part of a workpiece passing through the drive stage 42 engages the first and second rollers 48a, 48b, a second, opposing surface or part of the workpiece facing towards and engaging the third roller 48c. The workpiece is firmly engaged by all three of the rollers 48a, 48b, 48c and as a consequence, rotation of at least the first roller 48a results in the workpiece being driven axially through the drive stage 42.

In order to ensure that driving contact between the workpiece and the first, second and third rollers 48a, 48b, 48c is maintained, the third roller 48c is conveniently mounted upon a bracket 56 that is movable relative to the housing 46, a spring 58 being provided between the bracket 56 and part of the housing 46, the spring 58 urging the bracket 56 in a direction maintaining contact between the third roller 48c and the workpiece, in use.

Whilst as shown the drive stage 42 comprises three rollers, it will be appreciated that more or fewer rollers may be provided in the drive stage if desired without departing from the scope of the invention.

The bending stage 44 comprises a support 60 movably mounted relative to the housing 46. A hydraulic actuator 62 is provided to drive the support 60 between a rest position and an operative position (as shown). A control arrangement 64 controls operation of the actuator 62.

The support 60 carries a fourth roller 48d. The axis 50d of the fourth roller 48d is parallel to but offset from the axes 50a, 50b, 50c. The fourth roller 48d is positioned such that, when the support 60 occupies its rest position, the axis 50d of the fourth roller 48d lies upon a notional straight line interconnecting the axes 50a, 50b of the first and second rollers 48a, 48b. When the support 60 is moved to its operative position, it will be appreciated that the axis of rotation 50d of the fourth roller 48d is displaced away from this notional line.

The bending stage 44 further comprises a fifth roller 48e rotatable about a fixed axis 50e.

The housing 46 further carries a first sensor 66, for example in the form of a microswitch, which senses whether or not workpiece material is present at a first location to one side of the housing 46 adjacent the drive stage 42, and a second sensor 68 which, similarly, may take the form of a microswitch, which senses whether or not workpiece material is present at a second location to an opposite side of the housing 46 adjacent the bending stage 44. The outputs of the sensors 66, 68 are used by the control arrangement 64 in controlling the operation of the motor 52 and the actuator 62. The control arrangement 64 is conveniently of hydraulic form, the sensors 66, 68 comprising hydraulic switches.

In use, starting from a condition in which no workpiece is present within the tool 40, the control arrangement 64, using the outputs of the sensors 66, 68 which indicate the absence of workpiece material controls the motor 52 in such a manner that the rollers 48a, 48b, 48c of the drive stage 42 are not driven for rotation, and the actuator 62 holds the support 60 in its rest position.

Upon the subsequent introduction of a workpiece, the first sensor 66 detects the presence of the workpiece, and the control arrangement 64, in response to the output of the first sensor 66, causes the motor 52 to operate to drive the drive stage 42. The engagement of the workpiece with the rollers 48 of the drive stage 42, and the rotation of at least one of the rollers 48 of the drive stage 42 by the motor 52 causes the workpiece to be positively axially driven through the tool 40. As the support 60 is in its rest position, the fourth roller 48d is aligned with the first and second rollers 48a, 48b and so does not impart a bending load upon the workpiece as it passes through the tool. The tool thus operates to leave a straight end part on the workpiece. When the end of the workpiece reaches the second location and so is detected by the second sensor 68, the control arrangement 64, in response to this output of the second sensor 68, causes the actuator 62 to drive the support 60 to its operative position. In this position, the fourth roller 48d occupies a position in which, in order for the workpiece to continue to pass through the tool, the workpiece must adopt a bent form. The tool thus operates to bend the workpiece.

In bending the workpiece, loads are applied thereto which are reacted through others of the rollers 48. Some movement of the bracket 56 may occur to maintain the required contact between the rollers 48 and the workpiece.

The workpiece continues to be fed through the tool, and bent by the tool, until the opposite end of the workpiece passes the first sensor 66. The absence of workpiece at the first location may be used by the control arrangement 64 to instruct the actuator 62 to drive the support 60 back to its rest position. Continued operation of the tool thus allows the workpiece to pass through the tool without bending taking place, forming a straight section at that end of the workpiece. Once the free end of the workpiece passes the second sensor 68 and exits the tool, the control arrangement may switch off the motor 52.

It will be appreciated that the tool, when used in the manner set out hereinbefore, forms the workpiece into a form having straight end sections interconnected by a central section of substantially uniform radius of curvature. The workpiece may comprise a steel tube, for example of circular, elliptical or other cross sectional shape, and may, once finished, be used as a cover support hoop for use in a polytunnel structure or the like.

The tool is advantageous in that the workpiece is positively driven, not requiring manual feeding thereof, and so the risk of operator injury and the like is reduced. As it can automatically form straight end sections, a number of cover support hoops, for example, or substantially identical form can readily be formed. The tool may be readily driven and controlled hydraulically, for example using the hydraulic output from a tractor or the like.

If desired, a rotary encoder (not shown) or the like may be provided within the housing 46, monitoring the passage of the workpiece, the output of which may be used by the control arrangement 64 in controlling the location of the support 60 (or a second similar support) to allow the workpiece to be formed with sections having different radii of curvature. By way of example, the workpiece may further be formed with a central part of reduced radius of curvature. It will be appreciated that this represents just one option, and that a number of other workpiece shapes may be formed.

Where a rotary encoder or the like is used, it will be appreciated that the control arrangement 64 may need to be of electrical or electronic form rather than of hydraulic form.

Referring next to Figure 2, a machining device 10 in accordance with another embodiment of the invention is illustrated. The device 10 comprises a machine tool 12 and a drive stage or feed device 14. The machine tool 12 takes the form of a ring roller including a pair of fixed rollers 16a, 16b, each of which is rotatable about its axis, the rollers 16a, 16b being rotatably mounted to a housing 18. The tool 12 further comprises a moveable roller 20. The movable roller 20 is rotatably mounted upon a slider plate 22 that is movably mounted upon the housing 18 such that the axis of rotation of the movable roller 20 can be moved towards or away from a notional line 24 interconnecting the axes of rotation of the rollers 16a, 16b. The rollers 16a, 16b, 20 are each of steel construction, and each have substantially the same diameter as one another. The axes of rotation of the rollers 16a, 16b, 20 are substantially parallel to one another. At least one of the fixed rollers 16a, 16b is arranged to be driven for rotation by a drive motor (not shown).

In use, a workpiece 26 is fed through the tool 12, the workpiece 26 being fed in such a manner that the fixed rollers 16a, 16b are located to one side of the workpiece 26, and the movable roller 20 is located to an opposite side of the workpiece 26. Provided the spacing of the axis of the movable roller 20 from the notional line 24 is less than the sum of the radius of the movable roller 20 and that of one of the fixed rollers 16a, 16b, then in order for the workpiece to be fed through the tool 12, it is forced to adopt a curved configuration, the radius of curvature of which is dependent upon the spacing of the axis of the third roller 20 from the notional line 24.

In accordance with this embodiment of the invention, the device 10 further comprises the feed device 14 as noted above. The feed device 14 comprises a housing 28 within which are located first, second and third drive rollers 30a, 30b, 30c, each of which is of rubber or rubber-like material form. The drive rollers 30a, 30b, 30c could be of solid rubber or rubber-like material form. Alternatively, just the peripheries thereof may be of rubber or rubber-like material form. The drive rollers 30a, 30b, 30c are positioned such that when the workpiece is fed through the housing 28, two of the drive rollers 30a, 30b are located to one side of the workpiece 26 and the third roller 30c is located to the opposite side of the workpiece 26, parts of all three of the drive rollers 30a, 30b, 30c bearing against the outer surface of the workpiece 26. One of more of the rollers 30a, 30b, 30c may be adjustably mounted to ensure that such contact is maintained, in use. At least one of the drive rollers 30a, 30b, 30c is preferably arranged to be driven for rotation about its axis by a drive motor and associated gearbox 32.

A mounting arm 34 projects from the housing 28 and is pivotally connected to the housing 18 to mount the feed device 14 to the tool 12 in an articulated manner.

In use, the workpiece 26 is fed between the drive rollers 30a, 30b, 30c in the manner shown. All three of the drive rollers 30a, 30b, 30c bear against the outer surface of the workpiece 26, and the motor and gearbox 32 is operated to drive one or more of the rollers 30a, 30b, 30c for rotation. It will be appreciated that the rotation of the rollers 30a, 30b, 30c under the control of the motor 32, in combination with the engagement between the rollers 30a, 30b, 30c and the workpiece 26 results in the workpiece being positively driven through the feed device 14.

From the feed device 14, the workpiece is fed into the tool 12. As described hereinbefore, the feeding of the workpiece through the tool 12 results in the formation of a curve in the workpiece, the radius of curvature of which is dependent upon the setting of the tool 12. Adjustment of the setting of the tool 12 to adjust the radius of curvature formed in the workpiece 26 results in the direction in which the unbent part of the workpiece 26 changing, and articulation of the feed device 14 relative to the tool 12, as permitted by the pivoting connection therebetween, automatically accommodates this change. Figure 3 illustrates, diagrammatically, the position occupied by the feed device 14 where a smaller radius of curvature is to be formed in the workpiece 26.

It will be appreciated that the invention is advantageous in that the use of rubber or rubber-like materials for the drive rollers 30a, 30b, 30c increases the coefficient of friction between the drive rollers and the workpiece 26, reducing the risk of slipping therebetween as may otherwise occur especially where the workpiece is wet or oily. The workpiece is thus fed through the device 10 in a better controlled fashion than in typical devices. The improved control over the feed of the workpiece through the device 10 results in a better quality work product and reduces the risk of operator injury.

Where the tool 12 includes a driven roller, the speed of operation of the motor 32 is conveniently selected such that substantially no slipping occurs between the workpiece 26 and the driven roller of the tool 12. Whilst the use of rubber or rubber-like material drive rollers reduces slipping between the drive rollers and the workpiece, some slipping may still occur, and the speed at which the motor 32 is operated is preferably selected to take into account such slipping, ensuring that slipping between the workpiece and the rollers of the tool 12 is avoided. The motor 32 may be hydraulically powered and/or controlled, in use.

The invention is especially suitable for use in the formation of the cover support hoops of a polytunnel structure, such hoops typically being formed by forming a curve of substantially uniform radius of curvature in a length of a tubular material or circular cross sectional shape or of another tubular material form. Often, the cover support hoops are formed to their desired shaped on site, and so they are often formed using a ring roller tool out of doors, and the tubular materials from which the cover support hoops are formed may be wet and/or oily. The use of the invention is thus especially advantageous when used in the formation of such cover support hoops. It will be appreciated, however, that the invention is not restricted in this regard and may be employed in other applications.

Whilst described hereinbefore in relation to the feeding of a workpiece material into a ring roller, it will be appreciated that the invention may be employed with other forms of machine tool, whether controlled manually or in a CNC fashion.

It will be understood that a number of modifications and alterations may be made to the arrangement described hereinbefore without departing from the scope of the invention as defined by the appended claims.