Background to the Invention

[0001] This invention relates to an instrument assembly mountable on a pole.

[0002] It is often required to mount an instrument, for example a meteorological instrument, to a pole. In many prior art situations, the instrument itself is directly mounted to the pole. This is often done by drilling at least three holes into the pole, tapping the holes, and screwing the instrument to the pole. It is often difficult to access the top of the pole and perform these actions, as this may require a mobile elevating work platform. It is also difficult to remove the instrument for maintenance and/ or replacement.

[0003] It is known to secure a mount to the pole and attach the instrument to the mount. The attachment to the mount may require a variety of fasteners such as nuts and bolts, threaded joints, or clamps. A variety of tools is often needed to secure the fasteners to a variety of structural members.

[0004] These known solutions are also associated with several problems. Azimuth alignment is difficult to set, and difficult to adjust. If the instrument is removed for maintenance and/ or replacement, a repeat adjustment is also required. These instruments can often be deployed atop tall poles in challenging environments (at sea for example), making the adjustment and alignment even more difficult.

[0005] A further issue with the known arrangements is that if the holes are incorrectly drilled into the pole, then either the resulting position of the instrument is misaligned, or the top of the pole needs to be removed and new holes drilled. Additionally, prior art fixtures are often only suitable for a pole of a single diameter.

[0006] https: / / help.weatherflow.com /he/ en-us / articles / 115005229767-Siting- Installation-for-Tempest describes an instrument with a threaded skirt and threaded collar. As the collar is screwed onto the skirt, the skirt tightens around the pole. A problem associated with such a mounting arrangement is that the skirt and collar are manufactured for specific diameters of pole. Additionally, if the collar is unwound, there is a risk of it being dropped and falling to the bottom of the pole.

[0007] Instruments also often need to be grounded. This may be done by providing an electrical connection to the pole. A way in which this is done in the prior art is by providing external screws and wires to facilitate the electrical connection. This adds additional steps to the installation of the instrument, and additional complexity.

[0008] https://detail.1688.com/offer/584814872886.html shows a sensor for a streetlight photocontrol switch. A locking mount includes three openings of equal length, disposed evenly around a central axis. The openings are all significantly wider than locking members which engage them. The photocell could be attached in three orientations, which is unlikely to be a drawback for a photocell, but would be for any instruments that require alignment and calibration.

[0009] https:/ / www.vaisala.com/ sites/ default/ files/ documents/ WXT530- Users-Guide-M211840EN.pdf discloses a mounting kit for helping with the mounting of a transmitter on a pole mast. Hooked arms are slotted into three curved slits of constant width to lock the instrument to a mounting base portion. It appears the instrument could be attached to the mounting portion in three different orientations, which is associated with a risk of misalignment of the instrument.

Summary of the Invention

[0010] From one aspect, the present invention provides an instrument assembly comprising: a first portion; and a second portion detachably connectable to the first part; one of the first and second portions being a mount fixable to a pole; the first portion having at least one engagement member comprising a shaft and an engagement portion at a free end of the shaft, the engagement portion having a dimension greater than a dimension of the shaft in the direction of said dimension of the shaft; and the second portion having at least one opening comprising: a first part through which the engagement portion can pass in a first relative position of the first and second portions, and a second part having a dimension smaller than a width of the engagement portion to retain the engagement portion in a second relative position of the first and second portions; at least one of the first and second parts including an alignment element configured to reduce movement of the first portion relative to the second portion by at least one degree of freedom.

[0011] The second part of the opening may be a channel, which may be curved, the first and second relative positions being relative angular positions. There may be a plurality of openings sharing a common centre of curvature.

[0012] The alignment element may be a second engagement member on one of the first and second parts, engageable in a second opening in the other of the first and second parts. An embodiment of the invention includes three such engagement members and three corresponding openings. The engagement members and openings may be arranged to have a single order of rotational symmetry.

[0013] Embodiments of the inventions with such asymmetric engagement members and openings are not limited to engagement members with shafts narrower than heads or openings with differently-dimensioned first and second parts. Alternative openings could be of uniform width, the engagement portion being an angled portion of an engagement member for example formed from wire or sheet metal, engageable behind a lip of the opening.

[0014] The alignment element may comprise a ridge or a chamfer, for example a circular ridge or chamfer.

[0015] Each of the first and second part may comprise a cavity, forming a continuous cavity when the first and second parts are connected to each other. [0016] The at least one opening may have a catch for resisting relative motion of the engagement member which would occur during movement from the second relative position to the first relative position. The catch may be biased towards the engagement member for engagement therewith, for example with a spring. The engagement member may have a recess for engagement with the catch. The catch may comprise a ball for engagement with the recess.

[0017] The other of the first and second portions may be an instrument for measuring environmental characteristics, such as an anemometer.

[0018] From a second aspect, the invention provides method of detachably connecting together the first and second portions of the instrument assembly described above, the method comprising the steps of: aligning the first portion relative to the second portion with the alignment member; inserting the engagement portion into the opening, either simultaneously with or subsequently to the step of aligning the first portion; and moving the first portion relative to the second portion such that the shaft travels within the channel.

[0019] From a third aspect, the invention provides a mount for securing a device to an end of a pole, the mount comprising: a housing; a clamp connectable to the device and disposed at least partly within the housing, the clamp having at least one arm having an inner face and an outer face, the inner face being arranged to contact the pole when the mount is positioned on the end of the pole; and a securing loop located at least partially within the housing, and arranged around the at least one arm, such that the securing loop surrounds the pole when the mount is positioned on the end of the pole, the securing loop being in contact with the outer face of the at least one arm, the securing loop comprising: a tightener for varying the length of the securing loop such that the length of the loop may be reduced or increased, such that when the tightener reduces the length of the securing loop, the securing loop exerts a force on the outer face of the at least one arm to retain the at least one arm between the securing loop and the pole.

[0020] The at least one arm may be of metallic material. The at least one arm may depend from a connection portion of the clamp that is connectable to the device. The mount may have an axis intended to coincide with an axis of the pole, a free end of the or each arm being further from the axis of the mount than an end of the arm at the connection portion, at least in an unstressed state of the at least one arm. The clamp may comprise at least two or at least three arms. The arms may be equiangularly spaced around the axis of the mount.

[0021] The tightener may comprise a screw, for example a worm screw. In this regard, the securing loop may comprise a worm screw hose clamp.

[0022] In an embodiment of the invention, the housing has an opening, the tightener protruding through the opening. The opening may be a window in the housing.

[0023] The mount may include at least one azimuthal engagement feature for engagement with a pointer, such as a compass.

[0024] The device may be an instrument such as an anemometer.

[0025] From a fourth aspect, the invention provides a method of securing a device to an end of a pole, using the mount described above, the method comprising placing the housing over the end of the pole, such that the at least one arm is in contact with the pole, and actuating the tightener to reduce the length of the securing loop and exert force on the outer face of the arm such that the inner face of the arm exerts a force on the pole, thereby securing the securing mount to the pole. [0026] Prior to actuating the tightener, a pointer may be engaged with the azimuthal engagement feature(s), and the mount may be rotated to set an azimuth of the device.

Brief Description of the Drawings

[0027] Embodiments of the invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which:

[0028] Figure 1 is a perspective view of an instrument and a mount;

[0029] Figure 2 shows a mounting platform of the mount;

[0030] Figure 3 is a section through the mounting platform of Figure 1, showing engagement members in the first relative position;

[0031] Figure 4 is a section through the mounting platform showing the engagement members in the second relative position;

[0032] Figure 5 is a schematic vertical section showing the mounting portion and part of the operative portion when the mounting and operative portions are locked together;

[0033] Figure 6 is a perspective view of the mount;

[0034] Figure 7 is an exploded view of the mount;

[0035] Figure 8 shows the mount being secured to a pole;

[0036] Figure 9 is a first schematic vertical section through the mount, showing the securing loop;

[0037] Figure 10 is a second schematic vertical section through the mount;

[0038] Figure 11 shows setting the azimuth using a compass; and

[0039] Figure 12 shows setting the azimuth using an alternative pointer. Detailed Description of Particular Embodiments

[0040] Figure 1 shows an instrument 1 separated from a generally cylindrical mount 2. The mount is attached to a pole 4 and aligned for azimuth orientation. A means of attachment between the instrument 1 and the mount 2 is provided by one or more shouldered engagement members, here screws 5, located on the underside of the instrument 1 which interlock into arcuate keyholes 6 located on the mount 2.

[0041] The keyhole(s) 6, shown in Figures 2-4, are angularly positioned asymmetrically about the axis and provide for repeatable alignment by ensuring that the instrument 1 is connected in the same position if removed for maintenance or replacement.

[0042] In this embodiment, the keyholes 6 are through-holes in an upper plate 11, screwed to a housing 12 through screw holes 8.

[0043] An alternative embodiment is to locate the keyholes 6 directly into the mount as a moulding or casting.

[0044] To assemble the instrument 1 to the mount 2, the head of each shouldered screw 5 is angularly aligned to mate with the first, wider part 7 of its respective keyhole 6. The instrument is then rotated so that the shoulders of the shouldered screws 5 interlocks behind the second, narrower part of the keyholes 6.

[0045] The rotation angle to the end position is shown as 20 degrees, but could have any reasonable size.

[0046] A further alternative embodiment is to locate the keyholes in the instrument and the shouldered screws in the mount 2.

[0047] Figure 5 shows the catch mechanism. A hole or recess 9 is located in the head of the shouldered screw 5. This mates with a catch 10 comprising a spring loaded ball and provides a positive lock in the "home" position at the end of the keyhole 6. The catch may alternatively comprise a magnet, a roller, a spring loaded pin or a leaf spring.

[0048] The screws 5 take up less space than their corresponding keyholes 6 and catches 10. Therefore, by locating the screws 5 on the instrument 1 (as opposed to on the mount 2), the instrument 1 has the potential to be made smaller.

[0049] The arrangement described above provides repeatable and reliable installation of the instrument and facilitates its alignment to north and to the horizontal. It reduces vibrations and turbulence. Electrical grounding between the instrument and the mount is provided by the metallic engagement elements, here in the form of screws.

[0050] Figures 6 and 7 show how the mount 2 includes the plate 11, for attachment of the instrument. The plate 11 is attached to both the housing or enclosure 12, and an internal collet 55 using mounting screws 53, 57. A means to provide a continuous electrical path between the collet and the mounting platform is made with metallic pillars 56.

[0051] A hose clamp 54 is captivated by the assembly and used to clamp the assembly to a pole. The clamp may be a worm drive hose clamp and may alternatively or additionally comprise a spring, wire or ear clamp.

[0052] The mount 2 is pushed onto the end of a pole 58, shown in Figure 8, and adjusted for azimuth alignment. The worm drive hose clamp 54 is then tightened or loosened, using a suitable tool 59.

[0053] The worm drive hose clamp 54 is assembled into the enclosure 12 with its clamping screw 61 accessible through an opening, here a window 62 in the side of the enclosure and captivated by fitting the collet 55, having one or more kerf cuts along its length to create a multi-point mounting which self-centralises onto the pole 58 when the worm drive hose clamp 54 is tightened around it.

[0054] The window 62 of the enclosure 12 has the additional advantage that when tightening the clamp 54, any rotational force generated on the clamp 54 by the person mounting the mount will not cause the clamp to rotate relative to the enclosure 12 and the internal collet 55. This improves the ease of assembly and mounting.

[0055] The encasement of the internal components by the enclosure provides the means to reduce turbulent effects on the instrument adjacent to it.

[0056] The means for earth bonding of the instrument to the ground is by using threaded metallic pillars 56, shown in Figures 7 and 10, which provide a continuous electrical path between the pole 58, the collet 55 and the instrument mounting plate 11. The screws 53, 57 are used as means to make the electrical connection. An alternative embodiment to make the electrical connection may use a combination of studs, rivets, welded fasteners, clinch fasteners, screws and nuts.

[0057] A further alternative embodiment would be to combine the mounting platform and collet as one component, thus removing the need for any connection components.

[0058] With reference to Figure 11, an azimuth alignment means is provided by registration edges 64 for locating a compass 65. With reference to Figure 12, a further azimuth alignment means is provided by v-notches 66 for locating a pointer 67.

[0059] An alternative embodiment for this purpose may be notches, grooves, ribs, etched or printed markings.

[0060] The mount of the invention is easy to install and there is no need to drill any holes or cut the top of the pole. If the clamp is unfastened, it will not fall down the pole. The mount is suitable for a greater variation of pole diameters than has been the case hitherto. With electrical conductivity from the mount to the pole through the clamp/ collet, there is no need for an external wire. This provides reduced turbulence and hence more accurate instrument readings.