GB2229254A

GB2229254A - Position indicator assemblies for rotary mechanisms

Info

Publication number: GB2229254A
Application number: GB9002588A
Authority: GB
Inventors: Duncan Ross Stewart; Patrick William Pinfold
Original assignee: Valve Conversions Ltd
Current assignee: Hytork International Ltd
Priority date: 1989-02-07
Filing date: 1990-02-06
Publication date: 1990-09-19
Anticipated expiration: 2010-02-06
Also published as: GB8902627D0; GB2229254B; DE4003239A1; GB9002588D0

Description

? 1 POSITION INDICATOR ASSE1,1BlIES FOR ROTARY MECHANISMS This invention

relates to position indicator assemblies for rotary mechanisms.

Mechanisms having a partial rotary motion such as ball, plug or butterfly valves, and ducting fire dampersq are known. The rotary motions are largely either 90 degrees with normally two operating positions at 0 and 90 degrees, or 180 degrees which normally has either two positions at 0 and 180 degrees or three operating positions at 0, 90 and 180 degrees. There are also arrangements with other angular movements, for example 60 degrees and multiples of 60 degrees.

There are an increasing number of mechanisms using such rotary motions and these mechanisms are often situated in hazardous zones or where close access is difficult or dangerous for observation of the physical position of the mechanism. % Such mechanisms are often operated by actuators using remotely controlled electricalp pneumatic or hydraulic power.

Switch boxes may be fitted to the mechanism. which boxes operate to indicate the position of the mechanism by the operation of proximity or micro switches and which feed this information back to a control centre.

Failure of power supply may cause the feed back system to become inoperative, and it may thus not be possible to ascertain the actual settings of the mechanism from the feed back system. In some incidents it is of vital importance to confirm the position quicklyg and it may be impractical or dangerous closely to approach the mechanism.

An indicator assembly designed for use with rotary valves is known from EP-B-92714 and US-B-44945669 which describes a device which has a fixed cylindrical transparent cover locally marked to reveal windows and markings of a chequer board pattern in each of four quadrants and alternate marked and transparent areas on the top surface. An internal smaller cylinder is locally marked in a similar chequer board pattern so that the windows in the outer cylinder display the position of the inner cylinder when rotated by the mechanism whose position is indicated. With this design It is possible that a partial obstruction on the line of sight of an operatorg for example obstruction by structure or pipingo could obscure a windowg which' represents at maximum half of the axial visible surface. Alsog the particular described arrangement is specific to 90 degree rotation and two positions.

".i According to this invention a position indicator assembly for a rotary mechanism comprises two relatively movable surfaces, each surface having contrasting visual areast each area extending in the direction of relative movement and transversely theretol the areas of the two.surfaces together having a first visual effect in a first relative position and a different visual effect in a second relative positiong the extent of the areas decreasing in said transverse direction for at least part of the extent of the area in the direction of relative movement. Each area may extend the axial length of the surface.

The two surfaces may respectively be on first and second members one of which members is rotatable relative to the other.

The first member may be rotatable in the second member.

The surfaces may be cylinders with the areas being angularly and axially extending bands disposed so that each band is present at each angular position.

In one case there are two or four or six helical bands of equal pitch on each of the two surfaces.

The visual effect may be a single colour over the whole visible surface in one position and two alternating colours in a second position.

The areas on the outer member may be such as to permit or obscure sight of the surface on the inner member.

In another form the surfaces are conical.

There may be a further visual effect in a third relative position.

The indicator assembly may form the cover of a switch box.

According to this invention a position indicator assembly for a rotary mechanism has two relatively movable surfaces, each carrying contrasting visual areas, each area extending in the direction of relative movement and transversely thereto, the areas of the two surfaces together having one visual effect in first relative position and another visual effect in second relative positionp each area of each surface being present (having an extent) at each position in the direction of relative movement.

The extent may be zero at the axial end of an area.

There may be a further visual effect in a third relative position.

I - 5 The invention may be performed in various ways and some specific embodiments with possible modifications will now be described by way of example with reference to the accompanying drawingsp in which:

Fig. 1 is a perspective view of a valve assembly with position indicating device; Fig. 2 is an exploded view of the device; Fig. 3 is an axial section through the device; Fig. 4 shows a modified device; Fig. 5 shows another device; Figs. 6A and 6B show developed views of parts of Fig. 5; Figs. 7A and 7B; 7C; 7D and 7E; 7F show developed views of parts of other embodiments; Figs. 8Al 8B are developed views of other embodiments; and Figs. 9 and 10 are other embodiments.

Referring to Fig. 1. a flow control valve 10 is connected in known manner to a valve actuator 11, which may for example be a reciprocable piston operable by compressed air. The actuator has an operating element extending externally of an actuator cylinder 12 to operate a valve member 10A of the valve and on the other side to cooperate with a switch box 13 which includes a stem 149 moving with or constituted by the actuator element. The stem 14 has a flat end 15 engaged in correspondingly shaped part 16 of a receptor 17 in a device 18 for indicating the operating position of the valve member The receptor 17 moves with stem 11+ and, in the case showny has a cylinder 19 open at the lower end and rotatable within a fixed outer cylinder 20 having for example a mounting flange 21 at its lower end by which it can be mounted by bolts 22.

The valve may have two or more operating positions. Thus a two-position valve may have operating positions of 00 and 900 (measured from a datum). The 00 position may be open or closed for example. Other positions are possibleg for example 00 and 1800; or 00 and 600; or 00 and 1200.

The valve may for example have three positions e.g. 001 6009 1200 or 00, 9001 18oO.

The inner and outer cylinders 19, 20 are provided with markings which provide a visual indication of the position of the valve member.

The outer cylinder is transparent or translucent and the markings may be on the outer or inner surface of the cylinder, preferably the Inner. The markings on the inner cylinder would usually be on its outer surface but If the Inner cylinder is transparent or translucent the markings could be on the inner surface.

In the arrangement of Fig. 2, the curved inner surface 30 of outer cylinder 20 has coloured (e.g. yellow) helical bands 25. 26 and unmarked helical bands 279 28. Fig. 7A is a developed view of surface 30 with band 25 shown as 25A, 25B and band 28 as 28a and 28b.

- The curved outer surface 35 of the inner cylinder 19 has helical bands 36, 37, 389 39, which are alternately coloured with the colour on bands 25, 26 and a sharply contrasting colour (e.g. black). Fig. 7B is a developed view of surface 35; band 36 being shown as 36A, 36B; band 37 as 37ag 37B. As can be seen. the lower edge 42 intersects bands 39, 389 379 36 at equal lengths so that bands 37, 39 (yellow) and bands 38, 36 (black) each form 2-start helices with edge 42. On the cylinder 19, end edge 43 coincides with end edge 44 so that band 36A completes band 36B and band 37A completes band 37B. Similarly 25B and 26A complete 28B and 25B.

It will be seen by superimposing Fig. 7A on Fig. 7B that in one relative rotary position of surfaces 30, 35 band 38 is obscured by band 25A9 25B and band 36 is obscured by band 26 so that the visible cylindrical surface is all yellow. The cylinders are so mounted that this indicates one valve position e.g. 00. If the valve is now rotated to move the inner cylinder 9009 bands 36 and 38 are visible through the unmarked bands 279 28 (with bands 259 26 overlying bands 37, 39) so that the external visible effect is alternating yellow and black bands; this indicates the other valve position.

The yellow bands 37p 39 may carry the legend 'open' and the black bands 369 38 may carry the legend #closed'.

The visible bands extend the full axial extent of the effective visible surface.

Other colours can be used, The colours may be applied as a paint and may be enhanced by fluorescence# The valve may beg for example# a plug or ball or butterfly valve or a fire damper but the device can be associated with other rotary mechanisms The embodiment of Figs. 7A, 7B may be described as a two positiong two colour, two start helix arrangement which moves one start to move from alternating colours to a single colour.

In another embodiment the outer surface is as in Fig. 7E and the inner as in Fig. 7C. This is for two position (00, 1800)g two colour, single start helix. Again the relative movement is one start (18oo) to move from alternating colours visible to a single colour.

In another embodiment the outer surface is as Fig. 7E and the inner as Fig. 7D. This is a three position (00, 90% 1800), three colour, (say X, Y1 Z)q single start helix. To achieve the 900 and 18oo positions, move 1 start and 1 start respectively i.e.

900 and 18oo. With this embodiment, in the first position (00) two alternating colours X, Y are seen; at the second position (Fig. 7P) three colours X. Y9 Z are seen; and in the third position two colours X9 Z are seen.

In the embodiment of Figs. 51 6At 6B in effect one end of the cylinders of Fig. 2 is reduced in diameter to produce a cone. The effect is similar to the embodiment of Figs. 7E9 70 but the marked areas 50, 51, 52 are spiral-like of increasing width from an inner region.

The cone may be frusto-conical.

The embodiment of Figs. 8A, 8B has the inner surface 8B as a two colour three start helix arranged to 4 i - 9 change from alternating colours to a single colour for each 600 of relative angular movement.

The lead angle of the helix/spiral and the height of the cylinder/cone combined control the angle of lap of any one band. This should preferably always be such that at least the equivalent of one whole band is visible on any presented faceg i.e. 1800 as developed. This may show as a single band or parts but a rule of thumb is to ensure a lap of at least half the circumference of the cylinder.

The arrangements by adopting continuous visible contrasting indicators (bands) are independent of the position of view and visible indication across a high proportion of a minimum of 50% extending up to 100% in most cases of any visible surface regardless of the proportion visible.

The continuous indicators are designed preferentially to meet the requirements of the motion, using two contrasting colours or shading for two position application.

Three contrasting colours may be used for the three position application showing for example in a 0-90-1800 indicator two colours in the 0 and 180 degree positions and three colours in the 90 degree position.

The device adopts a fixed outer cover which does not rotate with the mechanism. This outer cover may be conical or cylindrical or a combination of the two shapes dependent on the particular use. This outer cover may be provided with means for fine positional adjustment relative to the rotating mechanism; for example pin and slot fastening.

An inner indicator is fixed to the mechanism and rotates with it and is shaped to match the contours of the outer cover and fit within it.

The outer cover is preferentially masked to provid alternate coloured opaque and clear transparent bands according to the intended use. The inner indicator carries coloured bands of a shape to match those on the outer cover so that on rotation the desired effect will be displayed.

The design of these bands is such that whatever sight is obtained, an indicator will appear across the whole visible face so that a partial obstruction will not detract from the indication.

1 1 When designed as a cone the helices are constructed as spiral curves delineating continuous bands of identical shape and size in alternating contrasting shades or colours. on both the outer cover and inner indicator such that In one position the outer bands obscure the contrasts and in another position reveal them. The top of the cone may be truncated.

When designed as a cylinder the helices are of equal width as single or multi-start arrangements with the necessary lead angles to match the intended_ use. The top of the cylinder may constitute a flat plate with alternating colour quadrants (see Fig. 2)g or a cone or hemispherical dome with spirals as previously describedp or halves 60. 61 (Fig. 4).

Partial or incomplete movement of the mechanism is indicated by a difference in the width of the stripes or bands which in the two required positions will either be totally obscured or with contrasting lines of equal' width.

In addition precise indication can be provided by which the inner and outer members have marked boundary lines which combined with the fine adjustment facility on the outer cover can be arranged to coincide at the desired position.

20 DEGREE ROTATION 2 POSITION In a preferred application a two start helix is used.

1 The top surface of a truncated cone or cylinder may carry spirals or triangles of colour respectively, continuing the areas on the curved surfaces.

The outer cover will carry alternate bands or spirals of colour A and transparency. The inner indicator will carry alternate bands of similar size to the outer cover of colours A and B. Consequently in the 0 degree position the device willy say, appear as a single colour and in the 90 position will display alternating colour bands. 180 DEGREE 2 POSITION ROTATION In a preferred application a single start helix is us ed.

The top surface of a truncated cone or cylinder may carry spirals or triangles respectively continuing the areas on the curved surfaces. The bands will bear colours and transparencies as in the 90 degree application with similar effect. 180 DEGREE THREE POSITION ROTATION 20 In a preferred design a single start helix is used. one colour (A) will be used on the outer cover alternating with transparent bands. The inner indicator will carry two colours (B) and (C) in similar alternating bands preferably different to the outer cover colour The positions will be indicated at 0 degrees by colours A andg showing through the transparency, the k - 13 indicator colour B. At the intermediate position 90 degrees the indicator will reveal half width bands of colours B and 0 against full width bands of colour A on the cover. 5 At 180 degrees the indicator will reveal alternate bands of colour 0 together with colour A on the cover. Similar arrangements may be used for other degrees of rotation, for example: A 3 start helix, 2 colour for 2 position 0-60 degree movement.

In some cases the indicator device may be Incorporated as an integral part of the switch box 13 providing the closure for same as well as an indicator, thus eliminating the need for a separate indie,,ting device.

Examples are shown in Figs. 9 and 10.

In Fig. 9 a sealed switch box base 60 contains and mounts control and signalling devices and is secured to an explosion-proof cover 61. The stem 14 extends through the top 62 of the cover to rotate the inner member 63 of the position indicating device which has its semi-transparent outer part 64 fixed to the base 60.

In Fig. 10 the cover 61 is omitted and tile position indicating device itself forms the switch box cover. The same elements 60 639 64 can thus be associated together with or without the cover 61.

1 The various indicating devices provide two relatively movable surfaces, each surface having contrasting visual areas, each area extending in the direction of relative movement and transversely theretot the areas of the two surfaces together having a first visual effect in a first relative position and. a different visual effect in a second relative position# the extent of the areas decreasing in said transverse direction for at least part of the extent of the area in the direction of relative movement.

They provide two relatively movable surfaces, each carrying contrasting visual areas, each area extending in the direction of relative movement and transversely theretop the areas of the two surfaces together having one visual effect in a first relative position and another visual effect in a second relative position, each area of each surface being present (having an extent) at each position in the direction of relative movement.

4 1

Claims

CIAIMS 1. A position indicator assembly for a rotary mechanism comprising

two relatively movable surfacesy each surface having contrasting visual areas, each area extending in the direction of relative movement and transversely theretop the areas of the two surfaces. together having a first visual effect in a first relative position and a different visual effect in a second relative position, the extent of the areas decreasing in said transverse direction for at least part of the extent of the area in the direction of relative movement.
2. An assembly as claimed in Claim 1, in which each area extends the axial length of the surface.
3. An assembly as claimed in Claim 1 or Claim 2, in which the two surfaces are respectively on first and second members one of which memberis rotatable relative to the other.
4. An assembly as claimed in any preceding Claim, in which the surfaces are cylinders with the areas being angularly and axially extending bands disposed so that each band is present at each angular position.
5. An assembly as claimed in any of Claims 1 to 3, in which there are two or four or six helical areas on each of the surfaces
6. An assembly as claimed in Claim 5P in which the areas are of equal pitch.

- 16
7. An assembly as claimed in any preceding Claimp in which the visual effect is a single colour in the first position and two alternating colours in the second position.
8. An assembly as claimed in any of Claims 1 to 49 in which the surfaces are conical.
9. An assembly as claimed in any preceding Claim, in which the areas of the two surfaces together provide a third visual effect in a third relative position.
10. A position indicator assembly for a rotary mechanism comprising two relatively movable surfacesy each carrying contrasting visual areas each area extending in the direction of relative movement and transversely theretop the areas of the two surfaces together having one visual effect in a first relative position and another visual effect in a second relative positiong each area of each surface being present (having an extent) at each position in the direction of relative movement.
11. An assembly as claimed in Claim 10. in which the areas provide a third visual effect in a third relative position.
12. An assembly as claimed in any preceding Claim# forming the cover of a switch box.

13, A position indicator assembly for a rotary mechanism substantially as hereinbefore described with reference to and as shown in pig. 2. or Fig. 4. or Fig, 5, or pigs. 6A9 6BY or Pigs 7A9 7B9 or Figs. 7Dy 7EY 7F9 or Figs. 7D9 709 or Pigs. 8Av 8B9 or Figs 9A9 9B@ 1 1 1 - 17 14, A rotary mechanism operably associated with a position indicator assembly as claimed in any preceding Claim.

X 1Nilsli.h&A incinw ino Patont nffir!#!- state House. 66 71 High Holbom. londonWC1R 4TP. Purther copies maybe obtamed from ThePatentOffice