WO2020182499A1

WO2020182499A1 - An apparatus for gripping a plurality of reinforcement rods

Info

Publication number: WO2020182499A1
Application number: PCT/EP2020/055332
Authority: WO
Inventors: Kim Ferrara; Ralph Douglas Cope; Anthony Dale Johnson
Original assignee: Rolls-Royce Plc
Priority date: 2019-03-09
Filing date: 2020-02-28
Publication date: 2020-09-17
Also published as: GB201903190D0

Abstract

There is disclosed a gripping apparatus for gripping a plurality of reinforcement rods for insertion into a laminated material. The gripping apparatus comprises a plurality of grippers arranged in an array. The grippers are moveable relative to one another within the array to define interstices for receiving rods from a supply. The gripping apparatus also comprises a retainer configured to retain the grippers in the array and an actuator configured to press the grippers together to grip rods in interstices between the grippers. There is also disclosed insertion equipment comprising the gripping apparatus.

Description

AN APPARATUS FOR GRIPPING A PLURALITY OF REINFORCEMENT RODS

The disclosure relates to an apparatus for gripping a plurality of reinforcement rods, for example, for insertion into a laminated material.

It is known to provide materials having desirable combinations of material properties by building the material in multiple layers, to form a laminated material. Examples of laminated materials are composite structures comprising plies of fibre-reinforced material, such as plies of carbon fibre reinforced plastic (CFRP). Such materials are anisotropic owing to their laminated construction.

It is known to provide through-thickness reinforcement in such laminated materials by inserting reinforcing rods into holes in the laminate material. Such insertion techniques are often referred to as“Z-pinning”, with“Z” referring to the thickness direction of a material having plies extending in orthogonal“X” and Ύ” directions. Through-thickness reinforcement may improve the resistance of the laminated material to delamination.

Insertion techniques may use rollers or a clamp to grip a rod and feed it towards the laminated material for insertion into the hole. Reliably inserting multiple reinforcement rods into respective holes using such techniques may be time-consuming and therefore expensive.

According to a first aspect, there is provided gripping apparatus for gripping a plurality of reinforcement rods for insertion into a laminated material, comprising: a plurality of grippers arranged in an array, wherein the grippers are moveable relative to one another within the array to define interstices for receiving rods from a supply; a retainer to retain the grippers in the array; and an actuator configured to press the grippers together to grip rods in interstices between the grippers. The grippers may be arranged in an array comprising at least one column comprising three or more grippers defining two or more interstices between them, such that actuation to press the grippers in the column together is to grip rods in the at least two interstices between the grippers in the column (e.g. simultaneously).

The gripping apparatus may comprise an alignment guide configured to guide the rods, in use, through the interstices between the grippers. The retainer may comprise a housing containing the grippers in the array. The alignment guide may be at least partly formed by a first wall of the housing. The alignment guide may be formed by the first wall and an opposing wall of the housing.

The alignment guide may comprise a plate comprising a plurality of guide holes for receiving the rods.

The housing may comprise an opening on one side of the housing. The actuator may be configured to extend through the opening to press the grippers. The housing may comprise a wall opposing the opening to react the pressing force on the grippers.

The alignment guide may be configured to permit no more than two rods to be received in the interstice between each pair of grippers. The alignment guide may be configured to permit no more than one rod to be received in the interstice between each pair of grippers.

The array of grippers may be arranged in a single layer. The grippers may be cuboidal. The grippers may have rounded edges and corners. The actuator may be configured to selectively release a pressing force on the grippers. The grippers may be configured to separate to permit movement of the rods through the interstices upon the release of the pressing force.

When the grippers are retained in a housing, the grippers and housing may comprise materials that result in sufficiently low friction to permit separation of the grippers within the housing when the actuator is not pressing the grippers. For example, such separation may be caused by a resilient reaction force from rods compressed between the grippers. The grippers and/or the housing may comprise aluminium and/or steel. The grippers may be biased to separate when the actuator is not pressing the grippers.

The actuator may comprise a compressible material for pressing the grippers.

Movement of the grippers may be restricted by the retainer along axes which are perpendicular to an actuator axis of the actuator (i.e. corresponding to a direction of movement of the actuator). The array may have multiple columns of grippers, each column having a plurality of grippers defining interstices between them. The array may have multiple columns and multiple rows of grippers. The actuator may be configured to act on each column of grippers simultaneously to press the grippers in each respective column to move together.

The gripper apparatus may comprise a plurality of pivotable rockers between the actuator and the grippers, each rocker being configured to transfer force applied by the actuator to a pair of adjacent columns of grippers or to a pair of adjacent rockers.

According to a second aspect, there is provided insertion equipment for inserting a plurality of reinforcement rods into respective holes in a laminated material, comprising: a support body; and a gripping apparatus in accordance with the first aspect, wherein the gripping apparatus is moveable relative the support body to move a plurality of reinforcement rods gripped by the gripping apparatus in use relative the support body for insertion into the laminated material.

The invention may comprise any combination of the features and/or limitations referred to herein, except combinations of such features which are mutually exclusive.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 schematically shows a side view of insertion equipment comprising a gripping apparatus for gripping a plurality of rods to feed into a corresponding plurality of holes in a laminated material.

Figure 2 schematically shows a perspective hidden parts view of a first example gripping apparatus for gripping a plurality of rods.

Figure 3 schematically shows a top view of a second example gripping apparatus.

Figure 1 shows an insertion equipment 10 for feeding a plurality of rods 12

simultaneously into a corresponding plurality of holes 14 in a laminated material 16.

The insertion equipment 10 comprises a gripping apparatus 20 and a support body 22. In this example, the support body 22 is in the form of a support rail, and the gripping apparatus 20 is moveable along the support rail.

In use, the gripping apparatus 20 grips a plurality of rods 12, and moves along the rail 22 towards the composite 16 while gripping the rods 12 to feed the rods 12 into the holes 14. The gripping apparatus 20 may otherwise be referred to as a clamp. The rods 12 may then be cut to separate end sections of the rods received within the holes 14.

The gripping apparatus 20 is configured to selectively release a gripping force on the rods 12 to permit relative movement between the gripping apparatus 20 and the rods. By way of example, the gripping apparatus 20 may move along the rods along a direction away from the laminated material, for example when the rods 12 are retained by a separate retaining mechanism. Further the gripping apparatus 20 may release the gripping force to permit the rods 12 to be fed through the gripping apparatus 20.

Figure 2 shows an isometric view of the gripping apparatus 20 with internal components shown in dashed lines. In this example, the gripping apparatus 20 comprises a retainer in the form of a housing 30, a plurality of rockers 50, an actuator 32 and a plurality of grippers 34.

In this example, the housing 30 is generally cuboidal having a rectangular upper plate 36 (a first wall) and an opposing rectangular lower plate 38 (a second wall). The upper plate 36 and the lower plate 38 each have a plurality of guide holes 40 arranged in an array. The guide holes 40 in the upper plate 36 align with the guide holes 40 in the lower plate 38 such that a plurality of rods 12 can be passed through the guide holes 40 in the upper plate 36 through the corresponding guide holes 40 in the lower plate 38. The upper plate 36 and lower plate 38 of this example therefore define an alignment guide for guiding a plurality of rods through the housing 30.

In this example the housing comprises an alignment guide defined by first and second opposing walls of the housing. In other examples, the housing may comprise an alignment guide defined by only one wall. Further, in other examples the alignment guide could be a separate component from the housing.

The example housing 30 comprises two opposing side walls 46, a retaining end wall 47 and an open end 48 opposing the end wall 47. The grippers 34 are generally cuboidal and are arranged within the cuboid housing 30 in an array having multiple columns, each extending from the end wall 47 towards the open end 48, and multiple rows extending between the first and second side plates 46. In this example, there are four columns and five rows of grippers 34. The grippers 34 are arranged in a single layer and are sized with respect to the housing so that they loosely retained within the housing 30 and are moveable relative one another.

The grippers 34 in the array define a plurality of interstices 42, 44 between them. In this example there is a first plurality of interstices 42 between opposing faces of the grippers which are substantially parallel to the end wall 47. There is also a second plurality of interstices 44 between opposing faces of the grippers which are

substantially parallel to the side walls 46. The grippers are retained within the housing 30 so that the first plurality of interstices 42 are aligned with the guide holes 40 of the housing to receive rods 12. The second plurality of interstices 44 in this example permit relative movement between the grippers 34 in different columns along the grip axis.

The grippers 34 are moveable relative one another along a grip axis parallel to the side plates 46. Relative movement between adjacent grippers 34 along the grip axis changes the size of the interstices 42 to selectively grip and release the rods 12 within the interstices 42.

In this example the grippers 34 have rounded edges and corners. The rounded edges and corners of the grippers reduce the risk of cutting or shearing the rods 12 when they are gripped by the grippers 34. However, the grippers 34 could be of any suitable shape which would allow the grippers 34 to grips the rods 12 between the interstices 42, such as cylindrical, with the axis of each cylindrical gripper aligned with the rows of grippers (i.e. the axis extending between the side plates 46). In this example, a plurality of rockers 50 are disposed at the open side 48 of the housing 30 in two rows; a first and second rocker 50a disposed in a first row, and a third rocker 50b disposed in a second row. Each rocker 50 comprises a base 52 and two contact portions 54, in the form of cylinders, which are attached to the base 52.

The rockers 50 are configured to transfer the force from the actuator 32 to a pair of adjacent grippers 34 or to a pair of adjacent rockers. In the first and second rockers 50a, the base 52a is configured to extend across two columns of grippers 34 and to fit within the open side 48 of the housing 30. The contact portions 54a are located on the base 52a such that each contact portion 54a is configured to contact the centre of a different gripper 34 in adjacent columns of grippers 34 at the open side of the housing 30.

For the third rocker 50b, the base 52b is configured to extend across two rockers 50a in the first row (i.e. the first and second rocker 50a). The contact portions 54b of the third rocker 50b are located on the base 52b such that each contact portion 54b is configured to contact the centre of a different, adjacent rocker 50a in the first row.

The actuator 32 is configured to extend across the third rocker 50b and to move along the grip axis to apply a pressing force on the rockers 50 and therefore also on the grippers 34. The actuator may be coupled to the housing and/or may be configured to extend through the open side of the housing. The actuator 32 moves along the grip axis to press the rockers 50 against the grippers 34 so that the grippers 34 are pressed against the end wall 47. The grippers 34 move together along the grip axis, thereby reducing the size of the interstices 42 to grip the rods 12 between opposing faces of adjacent grippers 34. Movement of the grippers 34 in directions perpendicular to the grip axis is restricted by the side walls 46 of the housing 30 and the upper 36 and lower plates 38 of the housing 30. Similarly, the end wall 47 retains the grippers 34 by reacting the pressing force of the actuator 32.

In use, the rockers 50 between the actuator 32 and the grippers 34 accommodate for varying rod diameters. Each of the rockers 50 is freely movable, and therefore can pivot to remain in contact with either of the respective columns when there is variation in the diameter of the rods passing through the alignment guide. Since the second row of rockers 50b is also freely moveable, it can also accommodate for the pivoting of the first row by pivoting itself, but the pivoting of the second row will be less pronounced compared with the pivoting of the first row because the rocker 50b is in contact with the centres of the first row of rockers 50a.

Therefore, the actuator 32 can remain in contact with the whole of the second row of rockers 50 even if one of the rods through the alignment guide breaks. This

arrangement therefore accommodates for varying diameters of rod and ensures that an equal force is applied to each of the columns of grippers 34. When the actuator 32 returns along the grip axis to release the grippers 34, the grippers 34 separate from each other so that they release the rods 12, for example under the action of a resilient reaction force from the rods 12. In this example, the grippers 34 are made of steel, but they can be of any material which has sufficiently low friction with the rods 12 to permit them to slide through the interstices 42 between the grippers 34 when the actuator 32 is not pressing the grippers 34. In other examples, the grippers 34 can be provided with a biasing mechanism which returns them to their original, released position, such as a spring within each interstice 42.

In this example, the alignment guide is arranged so as to permit only one rod 12 to pass through each interstice 42 between pairs of grippers 34. This allows the gripping apparatus to have more than two rows of grippers and accommodates for different diameters of rods, so that each rod passing through the alignment guide can be gripped by a pair of grippers. In other examples, the alignment guide may be arranged to permit a plurality of fibres to be received within each interstice. In some examples, the alignment guide may be arranged so that no more than two rods are received within each interstice 42. Limiting the number of rods 12 per interstice 42 to two ensures that the pressure applied by the grippers 34 to each rod 12 when gripping may be substantially equal despite differences in size of the rods 12, since the grippers 34 are also able to rotate to accommodate different rod diameters. When there is only one rod 12 in each interstice 42, the grippers 34 do not need to rotate to accommodate different widths of rods, such that the pressure applied to each rod 12 is equal. Although the gripping apparatus 20 has been described as comprising rockers 50, in other examples, the gripping apparatus may not have rockers. In yet other examples, the gripping apparatus may alternatively or additionally comprise an actuator comprising a compressible material which compresses when the actuator 32 presses the grippers 34. This ensures an equal pressure is applied to each of the rods 12 even if the rods 12 within the gripping apparatus 20 are of marginally different sizes such that one column of grippers 34 is longer than another column. Other arrangements may be provided to accommodate rods of different sizes.

Although it has been described that the gripping apparatus 20 comprises four columns and five rows of grippers 34, there can be any number of columns or rows. For example, there may be an even or an odd number of columns, and there may be no rockers. In other examples, there may be more columns in multiples of four, and more corresponding rockers in the first row, and second row. In such examples there may be a third row of rockers, wherein each rocker is configured in the same manner as the second row of rockers. In such examples, the rockers may form a pyramid, wherein the row of rockers closest to the actuator comprises one rocker.

Although it has been described that the alignment guide comprises upper and lower plates 36, 38 with guide holes 40, it will be appreciated that the alignment guide can be any suitable structure, such as a lattice, suitable for aligning the rods 12 within the gripping apparatus 20.

Figure 3 shows a further example of a gripping apparatus 120, as shown in a top view normal to the elongate direction of rods 12 through the apparatus. The gripping apparatus 120 may be used with the insertion equipment 10 of Figure 1. The gripping apparatus 120 comprises a retainer 130, an actuator 32 and a plurality of grippers 34. The actuator 32 and grippers 34 in this example are similar to the actuator 32 and grippers 34 described with reference to Figure 2.

In this example, the retainer 130 has a U-shaped profile and comprises an end wall 124, opposing side walls 126 and an open end 128 opposing the end wall 124. Gripper arms 129 extend from each opposing side walls 126 to support the grippers 34 in two columns. Each gripper arm 129 supports a respective gripper 34. The columns of grippers 34 extending from the end wall 124 towards the open end 128.

The arms 129 are configured to support the grippers 34 so that they are spaced apart from one another along each column to define interstices 142 between adjacent grippers 34 in the same column in the absence of a pressing force from the actuator. In use, rods 12 are received in the interstices 142 between pairs of grippers 34 as in the example gripping apparatus 20 of Figure 2.

In some examples the retainer 130 may include an alignment guide (not shown) which aligns the rods 12 to be received within the interstices 142 before and/or after they are received within the interstices 142. The alignment guide could be in the form of a plate with guide holes through which the rods 12 are fed. An alignment guide may be provided separate to the retainer 130. The actuator 32 extends through the open front end 128 of the retainer 130 and is configured to press the grippers 34. The actuator 32 may be coupled to the retainer 130. When the actuator 32 presses the grippers 34, the grippers move along a grip axis which is perpendicular to the end wall 124 such that the size of the interstices 142 between the grippers 34 is reduced so that the rods 12 extending through the interstices 142 are gripped by the grippers 34. When the grippers 34 are moved to grip the rods 12, the cantilevered rods 129 resiliently deflect to accommodate the movement.

When the actuator 32 returns along the grip axis and releases the pressure on the grippers 34, the rods 129 resiliently return the grippers 34 to their original position, so that the size of the interstices 142 are increased, and the rods 12 are released.

The biasing mechanism provided by the arms 129 in this example may be configured so that there is a clearance between the rods 12 and the grippers 34 in the absence of a pressing force from the actuator. Accordingly, the grippers 34 may be of any suitable material for gripping, and may not comprise a low friction material for sliding contact with the rods.

Although the gripping apparatus has been described with respect to an example use of gripping reinforcement rods for reinforcing a laminated material, the disclosure extends to gripping apparatus for gripping other linear elements, for example tape, chord, cable or rigid linear elements such as struts. Similarly, the disclosure extends to equipment for manipulating linear elements comprising a support and gripping apparatus moveable relative the support to move the linear elements.

Claims

CLAIMS:

1. Gripping apparatus for gripping a plurality of reinforcement rods for insertion into a laminated material, comprising:

a plurality of grippers arranged in an array, wherein the grippers are moveable relative to one another within the array to define interstices for receiving rods from a supply;

a retainer configured to retain the grippers in the array; and

an actuator configured to press the grippers together to grip rods in interstices between the grippers.

2. Gripping apparatus according to claim 1 , comprising an alignment guide configured to guide the rods through the interstices between the grippers.

3. Gripping apparatus according to claims 1 or 2, wherein the retainer comprises a housing containing the grippers in the array.

4. Gripping apparatus according to claims 2 and 3, wherein the alignment guide is at least partly formed by a first wall of the housing.

5. Gripping apparatus according to claim 4, wherein the alignment guide is formed by the first wall and an opposing second wall of the housing.

6. Gripping apparatus according to any of claims 2-5, wherein the alignment guide comprises a plate comprising a plurality of guide holes for receiving the rods.

7. Gripping apparatus according to any of claims 3-6, wherein the housing comprises an opening on one side of the housing, and wherein the actuator is configured to extend through the opening to press the grippers.

8. Gripping apparatus according to any preceding claim, wherein the grippers are cuboidal.

9. Gripping apparatus according to claim 8, wherein the grippers have rounded edges and corners.

10. Gripping apparatus according to any preceding claim, wherein the actuator is configured to selectively release a pressing force on the grippers, and wherein the grippers are configured to separate to permit movement of the rods through the interstices upon the release of the pressing force.

11. Gripping apparatus according to any preceding claim, wherein the actuator comprises a compressible material for pressing the grippers.

12. Gripping apparatus according to any preceding claim, wherein the movement of the grippers is restricted by the retainer along axes which are perpendicular to an actuator axis of the actuator.

13. Gripping apparatus according to any preceding claim, wherein the array has multiple columns of grippers, each column having a plurality of grippers defining interstices between them.

14. Gripping apparatus according to claim 13, wherein the actuator is configured to act on each column of grippers simultaneously to press the grippers in each respective column to move together

15. Gripping apparatus according to claim 14, comprising one or more pivotable rockers between the actuator and the grippers, each rocker being configured to transfer force applied by the actuator to a pair of adjacent columns of grippers or to a pair of adjacent rockers.

16. Insertion equipment for inserting a plurality of reinforcement rods into respective holes in a laminated material, comprising:

a support body; and

a gripping apparatus in accordance with any preceding claim, wherein the gripping apparatus is moveable relative the support body to move a plurality of reinforcement rods gripped by the gripping apparatus in use relative the support for insertion into the laminated material.