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Title:
SUPPORT- OR DRIVING WHEEL WITH ADJUSTABLE ROLLING DIAMETER
Document Type and Number:
WIPO Patent Application WO/2011/108942
Kind Code:
A1
Abstract:
A driving and/or support wheel (11) arranged to bear on a bearing surface (1b) on a translation element (lb) and provided with a hub (111) is described, in which a wheel element (114) formed of an elastic material is arranged between a first axial support element (115) and at least one linear actuator (117), and the at least one linear actuator (117) is arranged to apply a thrust force to the wheel element (114) in the axial direction towards the first axial support element (115) in order thereby to compress the wheel element (114) in its axial direction.

Inventors:
ULLESTAD, Sigbjørn (Tronesv. 32, Sandnes, N-4307, NO)
Application Number:
NO2011/000071
Publication Date:
September 09, 2011
Filing Date:
March 02, 2011
Export Citation:
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Assignee:
NMI HOLDINNG AS (Breimyra 18, Bryne, N-4340, NO)
ULLESTAD, Sigbjørn (Tronesv. 32, Sandnes, N-4307, NO)
International Classes:
B23D21/04
Domestic Patent References:
2000-12-28
Foreign References:
US5035037A1991-07-30
Attorney, Agent or Firm:
HÅMSO PATENTBYRÅ ANS (Postboks 171, Sandnes, N-4302, NO)
Download PDF:
Claims:
1. A wheel (11) arranged to bear on a bearing surface (lb) on a translation element (lb) and provided with a hub (111) , c h a r a c t e r i z e d i n that between a first axial support element (115) and a second axial support element (116) , a wheel element (114) formed of an elastic material is arranged, and at least one linear actuator (117) is arranged to compress the wheel element (114) in its axial direction by displacing the second axial support element (116) towards the first axial support element (115) .

2. The wheel in accordance with claim 1, c h a r a c t e r i z e d i n that the first axial support element (115) and a second axial support element (116) form guide flanges (119) which define a wheel tread (114a) .

3. The wheel in accordance with claim 1, c h a r a c t e r i z e d i n that the at least one linear actuator (117) is formed of at least one screw (117a) arranged in the axial direction out from the hub

(111) ·

4. The wheel in accordance with claim 1, c h a r a c t e r i z e d i n that the at least one linear actuator (117) is formed of several screws (117a) which are arranged around a wheel axle (13) and project in the axial direction out from the hub (111) .

5. The wheel in accordance with claim 1, c h a r a c t e r i z e d i n that the at least one linear actuator (117) is formed of a screw (117a) which is axi- ally movably attached to the hub (111) , and which bears supportingly on a disc (117b) whose edge portion (117d) bears on a second axial support element (116) .

6. The wheel in accordance with claim 1, c h a r a c t e r i z e d i n that the first axial support element (115) and a second axial support element (116) form convex, conical side abutment surfaces (115a, 116a) for the wheel element (114) .

7. The wheel in accordance with claim 1, c h a r a c t e r i z e d i n that the wheel (11) is a driving wheel .

8. The wheel in accordance with claim 1, c h a r a c t e r i z e d i n that the wheel (11) is a support wheel .

Description:
SUPPORT- OR DRIVING WHEEL WITH ADJUSTABLE ROLLING DIAMETER

The invention relates to a wheel arranged to bear on a bearing surface of a translation element and provided with a hub, more particularly by a wheel element formed of an elastic material being arranged between a first axial support element and a second axial support element, and at least one linear actuator being arranged to compress the wheel element in its axial direction by displacing the second axial support element towards the first axial support element .

When arranging a drive in which rotation is converted into translation and the displacement of an element is based on a driving wheel bearing on an element surface and converting a torque from the drive into pushing power directed in the moving direction of the element by friction between the driving wheel and the element surface, it is important that the driving wheel bears on the element surface by a sufficiently large power component perpendicularly to the element surface. This is often provided by the driving wheel being arranged with a resilient suspension which pushes the driving wheel against the element, possibly by a supporting base, for example a support wheel, being provided with a corresponding resilient mounting, pushing the element against the driving wheel, or a combination thereof. For an apparatus that must be built with small dimensions, for example because it is to be placed between other objects with little clearance, such resilient suspensions often are not very desirable because they are space-demanding . In such situations operation by toothed driving elements are often used, for example by a toothed wheel engaging a pitch rack, a chain wheel engaging a chain and so on. For apparatuses in which a discontinuous element moves out of a guide track to enter the guide track at the opposite end, such a toothed drive will often, because of deformation, create operational problems by the engaging element of the elongated element not meshing accurately with the driving wheel where the element is being moved into the guide track. In addition, it is often challenging to synchronize several driving wheels so that they are equally loaded during their simultaneous engagement with the element driven. An example of an apparatus with such challenges is an apparatus for cutting pipes submerged in water, for example when removing oil and gas field installations at sea. Such apparatuses include a U-shaped collar which surrounds a portion of the pipe to be cut, and a C- shaped element carrying a cutting device, for example a high-pressure water nozzle, is arranged to be moved along a circular guide track on the collar, this guide track being interrupted at the opening of the U. Figure 1 shows an example of such a cutting apparatus.

The invention has for its object to remedy or reduce at least one of the drawbacks of the prior art, or at least provide a useful alternative to the prior art.

The object is achieved through features which are specified in the description below and in the claims that follow.

A wheel is provided, in which a circular wheel element arranged concentrically with a wheel axis and formed of an elastic material is expandable at least in a radial direction by one or more linear actuators being arranged to apply an axially directed force to the whole or parts of a first end portion of the wheel element in order thereby to compress the wheel element in the axial direction. Opposite the point (s) of attack of the linear actuator (s) a first axial support element is arranged, abutting supportingly on a second end portion of the wheel tread element. Between the wheel element and the linear actuator (s) is preferably arranged a second axial support element arranged to distribute the compressive force from the linear actuator (s) over substantially the whole cross section of the wheel tread element . By its axial compression, the diameter of the wheel element will increase.

The axial support elements are preferably formed as circular guide flanges projecting beyond the diameter of the wheel tread element. Thus, they contribute to the wheel element being subjected to axial compression over the whole of its cross section, and the compression is converted in its entirety into radial expansion.

In its/their simplest form, the linear actuator (s) may be formed of several screws distributed around the centre axis of the wheel and releasably attached in a wheel bearing housing. An actuator arranged centrically, for example in the form of a disc bearing, by its outer periphery, on the second axial support element, the inner periphery forming an abutment for a screw head or a nut which is in rotatable engagement with a threaded portion formed in the centre of the wheel bearing housing, may also be used.

The invention relates more specifically to a wheel arranged to bear on a bearing surface of a translation element and provided with a hub, characterized by a wheel element formed of an elastic material being arranged between a first axial support element and a second axial support element, and at least one linear actuator being arranged to compress the wheel element in its axial direction by moving the second ax- ial support element towards the first axial support element .

The first axial support element and a second axial support element may form guide flanges defining a wheel tread.

The at least one linear actuator may be formed of at least one screw arranged in the axial direction out from the hub.

The at least one linear actuator may be formed of several screws arranged in the axial direction around a wheel axle, projecting in the axial direction out from the hub.

The at least one linear actuator may be formed of a screw which is axially movably attached to the hub and which bears supportingly on a disc whose edge portion bears on the second axial support element .

The first axial support element and the second axial support element may form convex, conical side abutment surfaces for the wheel tread element .

The wheel may be a driving wheel, alternatively a support wheel .

In what follows is described an example of a preferred embodiment which is visualized in the accompanying drawings, in which :

Figure 1 shows, in perspective, a pipe-cutting apparatus

placed in an initial position on a pipe which is to be cut ;

Figure la shows, on a larger scale, a portion of the pipe- cutting apparatus with a driving wheel according to the invention;

Figure 2 shows, on a larger scale, a side view of a driving wheel according to the invention; Figure 3 shows a cross section III-III according to figure 2 of the driving wheel; and

Figures 4 and 5 show cross sections of alternative embodiments of the driving wheel .

In figure 1 the reference numeral 1 indicates a pipe-cutting apparatus provided with a C-shaped translation element la carrying a working tool lc. A drive Id is arranged to move the translation element la along a circular path as several driving wheels 11 bear supportingly on a bearing surface lb constituting the entire external edge surface of the translation element la.

In the figures 2-5 a wheel hub 111 is rotatably supported on a wheel axle 113 by means of a wheel bearing 112. A circular first axial support element 115 is disposed concentrically on the hub 111, axially fixed against a shoulder 111a on the hub 111. A circular wheel element 114 formed of a flexible material, for example a rubber mixture, is arranged concentrically on the hub 111 supported on a side abutment surface 115a of the first axial support element 115. A circular second axial support element 116 is arranged concentrically on the hub 111 and abuts supportingly by one side abutment surface 116a on the wheel element 114. The axial support elements 115, 116 have a larger diameter than the wheel element 114, forming guide flanges 119 defining a wheel tread 114a formed of the shell surface of the wheel element 114.

A chain wheel 118 is attached in a rotationally rigid manner to the hub 111.

In figures 2 and 3, which show a first exemplary embodiment of the invention, several adjusting screws 117a form a linear-actuator system 117, the adjusting screws 117a being arranged in the axial direction around the wheel axle 113 and attached by a threaded connection to the hub 111. The axial support elements 115, 116 are provided with complementary cutouts through which the screws 117a are passed.

In figure 4, which shows a second exemplary embodiment of the invention, a linear actuator 117 is formed by an adjusting screw 117a being attached in a threaded portion 117c in the hub 111 and bearing supportingly on a disc 117b which bears on said axial support element 116.

When the linear actuator system 117 pushes the second axial support element 116 in the axial direction towards the first axial support element 115, the wheel element 114 is compressed in the axial direction and expands in the radial direction. The diameter of the wheel tread 114a thereby increases and an increased wheel pressure against the

translation element la is achieved without the use of a resilient mounting of the driving wheel 11. It is obvious to a person skilled in the art, having the knowledge of the invention, to use the same technique also on a support wheel.

In figure 5 is shown yet another exemplary embodiment of the invention in which the linear-actuator system 117 corresponds to the one shown in the figures 2 and 3 but the side abutment surfaces 115a, 116a of the axial support elements 115, 116 are of a slightly conical shape. In this embodiment it is an advantage if the wheel element 114 has a corresponding shape on its end surfaces.