GB2479373A

GB2479373A - Bleed screw operating tool with a plurality of keys slidably mounted on a bar

Info

Publication number: GB2479373A
Application number: GB201005782A
Authority: GB
Inventors: William Parish
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-04-07
Filing date: 2010-04-07
Publication date: 2011-10-12
Also published as: GB201005782D0

Abstract

A bleed screw operating tool 10 comprises a plurality of keys 12a, 12b, 12c each having a different profile 21, 26 configured for driving engagement with a corresponding bleed screw, and a bar 11 slidably supporting the plurality of keys 12a, 12b, 12c, the ends of the bar 11 having a profile 33 to prevent the keys 12a, 12b, 12c sliding off the bar 11. Each key 12a, 12b, 12c may have a bore 19 through which the bar 11 extends, and may be rotatable relative to the bar 11, about the bar axis. The key profiles 21, 26 may include a polygonal aperture or a projection for engaging a bleed screw. Each key 12a, 12b, 12c may comprise a body having opposed ends 16, (17, Fig 2), and each end may have a different profile.

Description

B'eed Screw Operating Toot The present invention relates to a tool for operating a b'eed screw and more particularly to a tool that that may be used to operate a plurality of different bleed screws.

Some closed fluid systems are furnished with bleed valves to enable air trapped in those systems to be released. A bleed valve essentially comprises a va've body defining an aperture and a b'eed screw that threadingy engages the aperture to close the valve and prevent fluid passing therethrough. The positive pressure of the system forces the trapped air through the aperture as io the bleed screw is gently loosened.

One example of a closed fluid system having a bleed valve is a vehicle braking system. Because air is a compressible fluid it must be purged from such systems otherwise it reduces the maximum braking pressure applied to the wheels. These bleed valves include the bleed screws described above, though they are often referred to as bleed nipples.

Another example of a closed fluid system in which trapped air must be released is a central heating system, particularly the radiators coupled to that system. Air is less dense than water so it often collects at the top of a radiator and because it is a poor thermal conductor compared to water the top of the radiator remains far cooler than the bottom. For that reason most radiators are furnished with a bleed valve located on their rear face or, more commonly, one of their side faces. The bleed screw of that type of valve often includes a square or tnangular shaped head and a suitably profiled small key is usually provided to operate the screw. However, those keys are easily mislaid and are sometimes difficult to use, particularly when the bleed screw is iocated on the rear face of the radiator where access Is limited.

it Is therefore a principal object of the present invention to provide a tool that may operate a plurality of different bleed screws in the event that the odglnal bleed screw key Is mislald. It Is a further object of the present invention to provide a tool that facilitates easy adjustment of the bleed screw even when access is limited.

According to the InventIon, there Is provided a bleed screw operating tool comprising: -apluralltyolkeyseachhavlngadifferentprofileconfiguredfordrMng engagement with a correspondIng bleed screw and -a bar sildably supporting the plurality of keys, the ends of the bar being profiled to prevent the keys sliding off the bar.

Each key may Include connection means which cooperate with the bar and permit relative translational movement between the key and the bar. For example, the connection means may include a groove defined on each key and through which groove the bar may extend. In a preferred arrangement the connection means include a bore formed through each key and the bar may extend through that bore, the relative dimensions of the bore and the bar beIng selected to permit relative sliding movement of the keys and the bar.

Mvantageously, relative rotation between the key and the bar and also relative rotation between the keys about the bar may be permitted. This may be essential when usIng the tool in confined spaces. Preferably the bore and the bar both have circular cross-sections to facIlitate smooth rotation between those parts, but rotation would also be permitted If only one of those parts has a circular cross-section. Indeed, provided the bore is sufficienUy large neither of those parts requires a circular cross-section.

The ends of the bar may be profiled once the keys have been located thereon and preferably by a simple forming process. For instance, the ends of the bar could be crimped, upset, bent or otherwise deformed to prevent removal of the keys. Preferably the length of the profUed ends is relatively sma so as not to reduce significantly the effective length of the bar along which the keys made slide. In one embodiment the bar has a total length of 90mm and each end profile is 5mm.

Advantageously at least one of the profiles includes an aperture configured for driving engagement with a correspondingly profiled head of a bleed screw. The aperture may be of any size and shape to fit a correspondingly profiled head of the bleed screw, but is most likely to be square or triangular because bleed screws having those shaped heads are most common. The apertures may also be polygonal and preferably hexagonal so as to fit regular nuts and bolts.

Many bleed screws, particularly those fitted to radiators, are located in a well or surrounded by a flange. Therefore the key or at least the portion thereof defining the aperture may be sufficiently small to locate in that well or flange to ensure full engagement of the aperture and the bleed screw head.

In one arrangement at least one of the profiles may include a projection configured for driving engagement with a recess defined on the bleed screw.

The shape and size of the projection is selected according to the size and shape of the recess with which it is to cooperate, but again it is likely to be polygonal and most likely square, triangular or hexagonal.

Advantageously the axis of each aperture and or projection may extend transversely to the axis of the bar. This way, the bar is less kely to be obstructed by adjacent components or other features of the item being bled as the tool is rotated about the axis of the bleed screw. Further, the tool may be easier to rotate by arranging the axes of the bar and the aperture or projection in that way.

Furthermore, each key may comprise a body having opposed ends and the profile may be defined on one of those ends. Preferably the body has a generaUy uniform cross-section and is most preferably cylindrical having two io circular end faces. Advantageously, the body may comprise two different profiles such that each is defined on a respective end of the body so that the tool may include more profiles and thus be suitable for use with more bleed screws. A preferred arrangement includes three keys defining a tota' of five profiles.

Advantageously the bodies will be cast so as to avoid multiple process in order to form all the features. However, when fewer tools are to be produced each key could be cut from a length of rod having the required diameter, the projections may be milled or otherwise machined and the apertures could be formed by drilling and broaching.

The tool may also include attachment means by which the tool may be secured to the item to be bled when not being used. For example, the attachment means may comprise a magnet adhered or otherwise fixed to the bar or even one of the keys and by which the tool may be attached to a rear face of a radiator so as to be out of sight. Alternatively, the bar itself may be magnetic.

By way of example on'y, one embodiment of the present invention will now be described in detail, with reference being made to the accompanying drawings, in which: Figure 1 is a front perspective view of a bleed screw operating tool according to the invention; Figure 2 is a rear perspective view of the bleed screw operating tool of Figure 1; Figure 3 is a perspective view of a radiator on which the invention may be used; Figure 4 is a perspective view showing part of the bleed screw tool of Figures 1 and 2 presented to a bleed screw provided on the radiator of Figure 3; and Figure 5 is perspective view corresponding to that of Figure 4, but showing part of the bleed screw operating tool engaged with the bleed screw.

Referring initia'ly to Figures 1 and 2, there is shown a bleed screw operating tool generally indicated 10 comprising a cylindrical bar 11 and three keys generally indicated 1 2a, 1 2b, 1 2c carried thereon. The bar 1 I is made of steel and has a length of approximately 90mm and a diameter of approximately 6.4mm (1/4 inch). Each end 13 of the bar is crimped to define a flattened portion having a length of approximately 5mm and a width greater than the diameter of the bar so as to prevent removal of the keys 12a,12b,12c.

Each key 12a,12b,12c comprises a cylindrical body having opposed first and second end faces 16,17 and a circumferential side face 18. A bore 19 extends diametricay through the circumferentia' side face 18 sidingy to receive the bar 11.

The first end face 16a of the upper key 12a is provided with a diametrical'y smal'er cyindrica projection 20 extending axiaUy therefrom and in which projection there is formed a square aperture 21 having a width of approximately 5mm. A square aperture 22 having a width of 5.85mm and a depth of approximate'y 8mm is formed in the second end face 1 7a of the upper key 1 2a. Therefore, this key is suitable for adjusting b'eed screws with a square head of approximately 5mm or 5.8mm wide.

The first end face 1 6b of the midd'e key 1 2b is furnished with a square projection 25 extending axiafly therefrom and a circular aperture 26 is defined within the end face 27 of that square projection. In the second end face 1 7b of that key there is formed a square hole 30 having a width of 7.95mm and a depth of approximately 8mm. This key is suitable for adjusting bleed screws having a large square head or a square aperture.

The lower key 1 2c includes a first end face 1 6c in which there is formed a triangular aperture 32 having sides of equal length and a depth of 8mm.

The second end face 1 7c of that key 1 2c is blank and includes no aperture or projection.

Figure 3 shows a conventional wall-mounted radiator 50 having a front face 51, a left side face (not shown) and a right side face 52. At the bottom of the right side face 52 there is provided a control valve 53 coupled to a flow pipe 54 and at the bottom of the left side face there is provided a lock shield valve (not shown) coupled to a return pipe 55. The radiator is also furnished with a bleed valve 60 located on the right side face 52 above the control valve 53 for releasing air coected inside the radiator 50. Referring to Figure 4, the bleed valve 60 comprises a valve body 61 defining an aperture (not shown) and a bleed screw 62 threadingly engaged with the aperture.

In use, prior to bleeding the radiator 50 the bleed screw 62 is located so that a key 12a,12b,12c having a corresponding prothe may be selected. In the present example, once an appropriate key 1 2a is selected the end face 1 6a with the required profile is then presented to the bleed screw 62 to ensure its size and shape is correct. The square aperture 21 of the key 12a is then urged into engagement with the bleed screw 62. The bar 11 may be grasped and used as a conventional tommy bar to effect rotation of the selected key 12a and thus the bleed screw 62. The other keys 12b,12c on the bar 11 may be slid away from the selected key 12a in use to avoid causing any obstruction and may even be grasped along with the bar 11 to facilitate easy manipulation of the tool 10, particularly for those with reduced dexterity.

It is to be understood that all dimensions indicated above are exemplary and are provided only to aid understanding. Those skilled in the art will realise that the size and shape of the described features will vary according to the intended purpose of the tool.

Claims

CLAIMS1. A bleed screw operating tool comprising: -a plurality of keys each having a different profile configured for driving engagement with a corresponding bleed screw; and -a bar slidably supporting the plurality of keys, the ends of the bar being profiled to prevent the keys sliding off the bar.
2. A bleed screw operating tool as claimed in claim 1, wherein each key has a bore through which the bar extends.
3. A bleed screw operating tool as claimed in claim 2, wherein each key is rotatable relative to the bar, about the bar axis.
4. A bleed screw operating tool as claimed in any preceding claim, wherein at least one of the profiles includes an aperture configured for driving engagement with a correspondingly profiled head of a bleed screw.
5. A bleed screw operating tool as claimed in any of claims 1 to 3, wherein at least one of the profiles includes a projection configured for driving engagement with a recess defined on the bleed screw.
6. A bleed screw operating tool as claimed in claim 4 or claim 5, wherein the aperture or the projection is polygonal.
7. A bleed screw operating tool as claimed in any of claims 4 to 6, wherein the aperture and or the projection each has an axis extending transverse to the axis of the bar.
8. A bleed screw operating tool as claimed in any preceding claim, wherein each key comprises a body having opposed ends and the profile is defined on one of those ends.
9. A b'eed screw operating too' as camed n cIam 8, wherein at east one body inc'udes two different profes, each being defined on a respective end of said body.
10. A b'eed screw operating toot as c'aimed in daim 8 or claim 9 and comprising three keys defining a total of five profiles.
11. A bleed screw operating tool as claimed in claim 1 and substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.