GB2444910A

GB2444910A - A work support

Info

Publication number: GB2444910A
Application number: GB0625350A
Authority: GB
Inventors: Yan Wang; Zhijian Wang; Venkata Kancharla; Nabil Gindy
Original assignee: Rolls Royce PLC
Current assignee: Rolls Royce PLC
Priority date: 2006-12-20
Filing date: 2006-12-20
Publication date: 2008-06-25
Also published as: GB0625350D0

Abstract

The support 10 includes a height-adjustable mounting 12 with a support pad 14 suspended about a universal bearing 15. The support pad is biased by elements 16 and 17 to a desired orientation when not associated with a work article. A contact portion for support of the article is, in use, turned towards the article about the universal bearing. The mounting may be a rod secured on a piston arrangement for adjustment. The contact portion may include three contact points. A number of work supports may be used extending upright from a bed.

Description

A Work Support The present invention relates to work supports and more

particularly to a work support utilised to support articles such as components to reduce deformation and vibration during machining processes.

It will be appreciated it is a requirement for machined articles such as components for machinery or engines to achieve appropriate dimensioning, surface conditioning or otherwise. An attached drawing marked "Prior Art" illustrates a typical prior work support utilised in association with other supports to present an article or component for processing. It will be understood that the work supports are required to avoid deformation and vibration of a component during the necessary machining processes. As can be seen in the Figure marked "Prior Art" a work support 1 incorporates a piston 2 having normally either internal or external screw threads to allow adjustment of the length of the piston 2 through employing different sized bolts. As can be seen, a component 3 is only engaged by a screw bolt 4 at a single point of contact 5. In such circumstances, if the article or component 3 is not parallel with a central axis A-A of the work support 1, that is to say piston 2, the normal screw bolt 4 cannot compensate itself and therefore machining forces 6 may distort the work piece or component 3. This will be particularly so if the component 3 is thin walled and/or relatively fragile.

In the above circumstances through the single point contact for each work support it will be appreciated in order for the overall work support arrangement to provide sufficient rigidity many work supports will be required to support flexible components adding to costs. Single point or reduced contact points result in non optimal support when the component normal direction is not parallel with the central axis A-A of the support 1 resulting in potential damage to a component and to the work support itself through uneven stressing.

In accordance with aspects of the present invention there is provided a work support comprising a mounting having a support pad, the mounting adjustable for height, the support characterised in that the support pad is suspended about a universal bearing, the support pad biased to a desired orientation when not associated with an article to present a contact portion for support of the article in use turned towards the article about the universal bearing.

Typically the mounting is a rod secured upon a piston arrangement for adjustment. Normally, the mounting extends upright.

Typically, the contact portion has three contact points.

Generally, the bias operates in at least two dimensions towards the desired orientation. Generally, the bias is arranged to urge the support pad to a perpendicular aspect. Typically, the upright aspect is substantially perpendicular to the mounting.

Additionally, the bias provides rotational bias to the support pad about the mounting. Typically, the rotational bias is towards a central position for the support pad.

Generally, the bias is provided by respective mechanical springs.

Possibly, the mounting is presented upon a screw thread for adjustability.

Typically, the contact portion comprises a plurality of contact points. Normally, there are three contact points to engage an article in use. Alternatively, the contact portion comprises a swivel end for the support pad to present a tiltable contact area for engagement with an article in use. Further alternatively, the contact portion comprises a single shoulder tiltable contact element. Further alternatively, the support pad has a double shoulder tiltable contact element.

Also in accordance with aspects of the present invention there is provided a work support arrangement comprising a plurality of work supports as described above.

Embodiments of aspects of the present invention will now be described by way of example only and with reference to the accompanying drawings in which:-Fig. 1 is a side view of a work support in accordance with aspects of the present invention; Fig. 2 is a schematic cross section in the direction of AA-AA depicted in Fig. 1; Fig. 3 is a lower perspective view of a work support in accordance with aspects of the present invention; Fig. 4 is a schematic illustration of a universal mounting and bias elements in accordance with aspects of the present invention; Fig. 5 is an illustration of a first alternative support pad in accordance with aspects of the present invention; Fig. 6 is a perspective view of a second alternative of a support pad in accordance with aspects of the present invention secured to a stand mounting; Fig. 7 is a schematic front perspective view of a third alternative support pad in accordance with aspects of the present invention secured to a stand mounting; Fig. 8 is a schematic illustration of a support arrangement in accordance with aspects of the present invention comprising a number of work supports.

It is known that three point contact provides greater, if not the maximum, rigidity with regard to work piece support through appropriate contact/support with a component or article in use. Unfortunately, as described above, previous systems have typically only provided single contact points for each work support and depend upon a number of work supports acting in concert in order to support a work piece article. Such an approach may be acceptable with regard to relatively rigid work piece articles but with thin walled or more fragile articles support is generally inadequate with respect to machining processes and forces.

In accordance with aspects of the present invention a work support is provided in which a tiltable contact element is provided. Typically, this tiltable contact element of a support pad comprises a plurality of raised points upon a support pad to engage an article. However, alternatively, and as will be described later, it is possible to provide a swivel point support pad to act as the tiltable contact member in accordance with aspects of the present invention. The support pad provides a contact portion which may comprise raised points or a swivel/tiltable element but in any event a stable broader engagement with the article will be provided.

Referring to Figs. 1 and 2 respectively illustrating a side view and a cross section of a work support 10 in accordance with aspects of the present invention. Thus, as can be seen, a stand mounting 2 is provided and secured to the end of a piston arrangement 3 to allow lateral displacement in use. In such circumstances, the piston arrangement 3 will allow height adjustment for the support 10 in accordance with aspects of the present invention. The stand mounting 2 presents a support pad 4 through a universal bearing 5. This universal bearing 15 allows the pad 4 to rotate freely in three dimensions against a bias combination comprising a tilt spring 6 and a rotation spring or springs 17. Thus, with movement about the universal bearing as well as lateral displacement by the piston arrangement 13 it will be understood six degrees of freedom are provided. This tilt and adjustable with regard to the support pad 4 is utilised as will be described below in order to achieve three point or flat abutment between the support pad 14 and an article to be machined or presented by a work support in accordance with aspects of the present invention.

The tilt spring 6 is arranged to ensure that an upper face of the support pad 4 remains perpendicular to the longitudinal direction of the work support 10 and in particular the piston 3 and stand mounting 12 when not in contact with an article or component.

The rotation spring or springs 17 engages the support pad 14 to ensure that against the universal bearing 15 the support pad is presented in a desired orientation hereinafter referred to as a central position when not in contact with an article to be machined. In such circumstances, without engagement with an article the support pad 14 will not rotate about its own centre of axis generally upon the bearing 15 extending through the stand mounting 12.

In Fig. 1 the tilt bias provided by the tilt spring 16 is illustrated by arrowheads 18 and the rotation bias provided by the rotation springs 17 by arrowheads 19. In the above circumstances it will be appreciated that without engagement with an article the support pad 4 through the bias provided by the spring 6, 7 assumes a desired orientation which is predictable in use. It will also be understood that the piston 3 and therefore the work support 10 generally has screw threads 20. Thus, an initial height of the support 10 can be adjusted along that screw thread 20 and also through orientation about the screw thread the desired orientation presented appropriately to receive an article to be machined during use and upon approach.

As indicated above, three point contact provides rigidity with regard to location of an article such as a component to be machined. In such circumstances a contact portion of the pad 4 incorporates nuts 21 which are raised above a platform and so provide points of contact with an article. Again, as indicated above, by rotation about the screw thread and the known orientation provided by the bias of springs 6, 7 about the universal bearing 5 predictability can be provided to receive a work piece and therefore typically in conjunction with other work supports in accordance with aspects of the present invention presentation of an article can be improved.

Fig. 3 provides an upward perspective view of the work support as depicted in Figs. 1 and 2. For illustration and clarity purposes similar reference nomenclature has been used. Thus, as can be seen, the pad 14 is orientated upon the universal bearing 15 extending from the stand mounting 12 secured upon the piston 13. The bias springs 16, 17 act upon the pad 14 to ensure in the condition depicted in Fig. 3, that is to say without engagement with a work piece article, the platform 14 is appropriately presented in a desired orientation. This orientation, as indicated, is with the support pad 14 generally perpendicular to the major axis of the support 10. This perpendicular orientation, as indicated, is generally achieved through tilt springs 16 whilst the rotation springs 17 cause centralisation of the platform 14 to a known orientation relative to the piston 13. In such circumstances, by turning of the support 10 about the screw thread 20 it will be understood that the platform 14 can be presented in a work support arrangement as described below to receive an article for machining.

Fig. 4 illustrates the stand mounting 12, which is secured to the piston 13 (not shown) and the universal bearing 15 which is associated with the pad 14 (not shown) through appropriate mountings. As indicated previously, the tilt spring bias 16 is provided to create appropriate orientation of the pd 14 when not in engagement with an article. The spring bias 16 acts against parts of the piston 3 (not shown) and parts of the bearing 15. Similarly, as indicated above, the rotation bias springs 17 are positioned to ensure that the universal bearing 15 remains at its central position when not in contact with a component and the platform does not rotate about its central axis. The springs 16, 17 are normally mechanical springs.

By the above approach it will be appreciated that the support pad provides three contact points (upstanding nuts 21) which will increase the rigidity of presentation of an article and reduce the number of work supports needed in a work support arrangement to adequately present and support an article for machining.

Furthermore, by providing three points it will be understood that the normal surface direction of the article need not be parallel with the central axis of the work support 10 as the support pad can tilt against the bias or rotate against the bias until the three point contact with the article is achieved. This adjustment achieves a "soft" compensation within the work support for uneven surfaces of an article to be supported and will always ensure the three points of contact 21 of the support pad 14 engage and contact the article to be supported in use.

The height and other aspects of the points can be chosen dependent upon the uneven surface of the article to be supported. In any event it will also be understood that generally the support pad will be associated with the universal bearing through an appropriate attachment mechanism. This attachment mechanism may be a screw thread or other mechanism such that support pads can be interchanged dependent upon the article to be supported.

Figs. 5 to 7 illustrate further approaches with regard to provision of a support pad 14 and in particular a tiltable contact element in accordance with aspects of the present invention. As indicated, tilt and rotation for orientational presentation of the support pad 14 can be achieved through the universal bearing acting against the bias springs 16, 17. However, as illustrated in Fig. 5, the support pad can be provided through a swivel element which can tilt and rotate itself into engagement with an article to be supported. In Fig. 5 a swivel support pad 51 is located upon a piston 52. The contact portion of the pad 51, as indicated, is allowed to swivel such that an end 53 which is tilted can be turned to an appropriate orientation in conjunction with the desired orientation achieved through the bias as described previously. Thus, the end 53 is turned such that it is ready to receive a presented article. In order to achieve such orientation it will be appreciated that the swivel is rotated about a screw thread 54 as required.

It will be understood that the end 53 may take the form of a swivel ball in a ball socket and therefore may itself be able to tilt in use to accommodate marginal mis-alignment from a normal flat_to_f1at! presentation for the article to the surface 53.

Fig. 6 illustrates a support pad 61 again located upon the universal joint 62 and then to a piston 63. As illustrated in Fig. 6b, the support pad 61 has a shoulder 64. Thus, the support pad can support an article or components which have flat, cylindrical and/or conical walls with smooth contact surfaces for engagement with the shoulder 64 and other parts of the support pad 61.

A further alternative is illustrated in Fig. 7 where a double shoulder 74 support pad 71 is provided. In such circumstances, a well or channel is provided within the support pad 71 such that the support pad can support flat, cylindrical and/or conical walls with smooth contact surfaces with generally additional stability in comparison with support pads 61 as depicted in Fig. 6, due to the extra shoulder 74.

Fig. 8 provides a schematic illustration of a work support arrangement 90 in accordance with aspects of the present invention. Only three work supports 91 are illustrated for clarity but, as indicated above, generally a larger number will be utilised in order to appropriately support and present an article 92. As can be seen, the work supports 91 act in concert to support the article 92. Each work support 91 has a support pad 93 presented upon a piston with a universal bearing and bias elements to present the support pads 93 in use. In such circumstances, as can be seen, each support pad 93 is tilted appropriately against the bias about the universal joint in order to be brought into a normal, that is to say, substantially flat association with the article 92 surface engaged. As indicated above, typically the pads 93 will have three points of contact for stability and rigidity of presentation in order to account for surface distortions and unevenness in the article 92. However, where the article 92 is smooth, it will be understood that swivel or shouldered support pads, as described with regard to Figs. 5 to 8, may be used as the evenness will allow flat surface to surface contact rather than utilisation of three point contact as described above.

In use the work supports 91 will be orientated upon a bed 94 and extended appropriately such that the pistons and support pads generally are upright. However, it will also be understood where appropriate the work supports 19 may be orientated upon a curve or shelves or steps in order to present the support pads 93 in use. Without the article 92 the pads 93 will all be orientated appropriately dependent upon the bias created about the universal bearing. Once the article 92 is orientated and rendered up to the support pads 93, these pads will tilt and turn appropriately to achieve the most robust and respective engagement with the article 92 against the bias and around the universal bearing. In such circumstances, the article 92 is well supported.

The actual number of work supports 91 in accordance with aspects of the present invention will depend upon operational requirements, the nature of the article 92 and the aggressiveness of machining to be applied to the article 92.

Modifications and alterations to aspects of the present invention will be appreciated by those skilled in the art. Thus, as indicated, generally a multi point contact surface for the support pads will be utilised to account for unevenness in the surface of the article to be supported but a flat support pad surface may be used if tilted. This flat support surface may have a compliant upper layer or surface to allow for some adjustment or, as indicated above, provision of a swivel to allow for small adjustment into engagement with the article but with most adjustment achieved through the tilt and rotation about the universal bearing against the bias.

Claims

Claims 1. A work support (10) comprising a mounting (12) having a

support pad (14), the mounting adjustable for height, the support characterised in that the support pad is suspended about a universal bearing (15), the support pad biased by elements (16, 17) to a desired orientation when not associated with an article (92) to present a contact portion for support of the article in use turned towards the article about the universal bearing.
2. A support as claimed in claim 1 wherein the mounting is a rod secured upon a piston arrangement (13) for adjustment.
3. A support as claimed in claim 1 or claim 2 wherein the mounting extends upright.
4. A support as claimed in any of claims 1, 2 or 3 wherein the contact portion has three contact points.
5. A support as claimed in any preceding claim wherein the bias (16) operates in at least two dimensions towards the desired orientation.
6. A support as claimed in any preceding claim wherein the bias is arranged to urge the support pad to a perpendicular aspect.
7. A support as claimed in claim 6 wherein the upright aspect is substantially perpendicular to the mounting.
8. A support as claimed in any preceding claim wherein the bias (17) provides rotational bias to the support pad about the mounting.
9. A support as claimed in claim 8 wherein the rotational bias is towards a central position for the support pad.
10. A support as claimed in any preceding claim wherein the bias is provided by respective mechanical springs (16, 17)
11. A support as claimed in any preceding claim wherein the mounting is presented upon a screw thread (20) for adjustability.
12. A support as claimed in any precethng claim wherein the contact portion comprises a plurality of contact points (21)
13. A support as claimed in claim 12 wherein there are three contact points to engage an article in use.
14. A support as claimed in any of claims 1 to 11 wherein the contact portion comprises a swivel end (53, 81) for the support pad to present a tiltable contact area for engagement with an article in use.
15. A support as claimed in any of claims 1 to 11 wherein the contact portion comprises a single shoulder tiltable contact element (61)
16. A support as claimed in any of claims 1 to 11 wherein the support pad has a double shoulder tiltable contact element (71)
17. A work support substantially as hereinbefore described with reference to the accompanying drawings.
18. A work support arrangement (90) comprising a plurality of work supports (91) as claimed in any of claims 1 to 17.
19. An arrangement as claimed in claim 18 wherein the work supports are presented upon a bed (94) such that the work supports extend substantially upright from the bed.
20. A work support arrangement substantially as hereinbefore described with reference to the accompanying drawings and in particular Fig. 8.