Enclosure

Abstract

The invention relates to an enclosure 100 for a drive unit. The enclosure 100 has a plurality of faces and is arranged to house components. A first face of said plurality of faces comprises an outer portion and at least one recessed portion. A first projection is provided projecting from a recessed portion of the first face. Furthermore, the first projection is arranged for engagement with a structure to which the enclosure 100 is to be mounted.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit and priority of Great Britain Patent Application No. 1208306.9 filed May 11, 2012, and Great Britain Patent Application No. 1205781.6 filed Mar. 30, 2012. The entire disclosures of the above applications are incorporated herein by reference.

FIELD

The invention relates to an improved enclosure, and in particular to an improved enclosure having an integral formation for mounting the improved enclosure to a DIN Rail.

BACKGROUND

DIN rails are well known. In general, they are elongate structures which are mounted substantially horizontally on a surface such as a wall or inside an equipment cabinet and which are used for mounting equipment. For example, control equipment such as a drive unit can be mounted using a DIN rail. Usually, DIN rails are metal. For example they may be made from carbon steel and/or may be zinc plated. A DIN rail may be rolled from a metal sheet into any suitable cross sectional shape. For example, C-section, G-section and Top-hat cross sectional shapes can be implemented for a DIN rail.

A drive unit (also simply referred to as a “drive”) is a well known piece of equipment, used in a wide range of mechanical systems. A drive unit includes and/or is connected to a motor which moves a load in a mechanical system. The drive unit includes control means for controlling operation of the motor. The drive unit includes electronic components which are either completely housed within, or at least partially covered by, an enclosure. The enclosure of a drive unit is generally a cuboid or box shape with front and rear faces, top and bottom faces and two opposing side faces. However, other enclosure shapes are possible.

It is known to mount a drive unit to a DIN rail using a formation such as a clamp that can connect to a face of the drive unit (usually the rear face) and which hooks on to, or otherwise engages with, the DIN rail. Such a clamp is provided separate to a conventional drive unit and can connect thereto in any suitable manner—for example by using additional parts such as bolts and/or screws to form a secure attachment. The cross sectional shape of the clamp can be selected so as to be compatible with the cross sectional shape of the DIN rail to which the drive unit is to be mounted.

When conventional drive units are mounted to a DIN rail the attachment means between the drive unit and the DIN rail takes up space, and usually creates an unnecessary gap between the rear face of the drive unit and the DIN rail. This means that the entire assembly is bulkier than is necessary for the correct functioning of the drive unit. When the drive unit is mounted inside an equipment cabinet or in any other location where space is at a premium, this wasted space is inconvenient and potentially costly. Furthermore, the fact that a separate formation such as a clamp is needed for mounting a conventional drive unit to a DIN rail makes the mounting process more complicated and time consuming for the user.

SUMMARY

An invention is set out in the claims.

According to an aspect there is provided an enclosure for a drive unit, said enclosure having a plurality of faces and being arranged to house components, for example heat-generating components, wherein a first face of said plurality of faces comprises an outer portion and at least one recessed portion and wherein a first projection is provided projecting from a recessed portion of the first face, said first projection being arranged for engagement with a structure to which the enclosure is to be mounted.

The enclosure may further comprise a second projection projecting from a recessed portion of the first face, said second projection also being arranged for engagement with a structure to which the enclosure is to be mounted. The first and second projections may project from different respective recessed portions or from first and second respective parts of the same recessed portion of the first face. The first and second projections may be arranged for location of at least part of the structure to which the enclosure is to be mounted therebetween.

The first projection and/or the second projection may be provided integral to said first face. The first face may be a rear face of the enclosure.

The first projection may comprise a free end, distal to the respective recessed portion, wherein said free end does not extend outwards of the outer portion of the first face. The second projection may comprise an outer surface, distal to the respective recessed portion, and wherein said outer surface does not extend outwards of the outer portion of the first face.

The projections may comprise any suitable inter-engagement means. The first projection may comprise a clip. The second projection may comprise a hook.

The enclosure may further comprise at least one vent provided on a face thereof. It may house at least one cooling component, such as a heatsink. The enclosure may house an electronic circuit and an apparatus for protecting said electronic circuit from an airflow, said apparatus comprising a cover means for covering at least part of the electronic circuit and a guide means for guiding an airflow around the electronic circuit.

The structure to which the enclosure is to be mounted may comprise a DIN rail.

FIGURES

Embodiments and examples will now be described with respect to the appended figures of which:

FIG. 1 shows an improved enclosure include an integral clip.

OVERVIEW

In overview, an improved enclosure is provided, said improved enclosure being suitable for a drive unit. The improved enclosure facilitates mounting of the drive unit to a structure such as a DIN rail in a straightforward and efficient manner.

The improved enclosure preferably comprises a recessed portion on at least one face, usually the rear face, thereof. It further comprises a formation such as a clip projecting from that recessed portion, wherein that formation is suitable for mounting the improved enclosure to a DIN rail. The clip is preferably provided integral to the enclosure.

The improved enclosure preferably also comprises a second formation such as a hook projecting from a recessed portion of the at least one face from which the clip projects. For example, the clip may project from a lower part of a recessed portion and the hook may project from an upper part of the recessed portion thereabove, wherein the clip and hook are located relative to one another so as to accommodate (at least part of) a DIN rail therebetween. The first formation does not have to be a clip. It may be a latch, a hook or nay other suitable engagement and feature or combination of engagement features. The second formation does not have to be a hook. It may be a plurality of hooks or any other engagement feature(s) which can engage with part of a DIN rail for securement of the improved enclosure thereto.

The enclosure is suitable for housing electronic components. The arrangement and/or location of components within the enclosure may be selected to enable part of the surface of the enclosure to be recessed, so that one or more formations such as a clip may project therefrom without adding significantly to the maximum outer dimensions of the enclosure. Preferably, the clip (and/or other formation(s)) should not extend outward of any other part of the enclosure face from which it projects, so as not to add to the maximum outer dimensions of the enclosure at all. A mechanical barrier device and/or intelligent venting can be used to further enhance the arrangement of the components within the enclosure and/or to provide more degrees of freedom for the shape and size of the enclosure.

By providing one or more formations such as a clip projecting from a recessed portion of a face of a drive unit, the drive unit can be mounted in a compact manner, with the front to rear depth of the drive unit being as small as possible. The clip can engage with a DIN rail (or other structure) without the need for tools or additional fixing means such as screws or bolts. Furthermore, it can enable the drive unit to be dismounted from the DIN rail by a user in a straightforward and quick manner, but at the same time will keep the drive unit securely attached to the DIN rail unless the user wishes to dismount it. If a second formation such as a hook is provided in conjunction with the clip, the two formations can work together to provide a secure attachment of the enclosure to the DIN rail.

By providing a clip that is integral to a drive unit, there is no need for additional fixing means such as screws or bolts. This enhances the ease and speed with which the drive unit can be mounted to a DIN rail. Furthermore, it reduces the number of component parts which the manufacturer has to make and/or supply to the end user. Providing a second integral information such as hook also gives rise to such advantages.

DETAILED DESCRIPTION

An improved enclosure for a drive unit can be better understood with respect to FIG. 1.

The view of the enclosure 100 given in FIG. 1 is from behind and to the right of the rear of the enclosure 100. As shown therein, the enclosure 100 comprises a first side face 102, a rear face 104 and a top face 106. Although not shown, according to an embodiment the enclosure 100 further comprises a second side face substantially opposite the first side face, a bottom face and a front face that may comprise a user interface, for example for providing control input to the drive unit. According to an embodiment, the enclosure does not include six faces. For example, the bottom face may be omitted.

The first side face 102 in FIG. 1 comprises a vent 108 for allowing hot air to escape from within the enclosure 100. As will be understood by the skilled person, many items of electrical equipment and electronic components—such as those within a drive unit—generate heat during operation. It is important for the heat generated within the enclosure 100 during operation of the drive unit to be channelled away as efficiently as possible, to optimise operation of the drive unit. The venting provided in the improved enclosure 100 described herein can be of any suitable type. For example, and as shown in FIG. 1, the vent 108 in the first side face 102 of the enclosure 100 can be provided in a recessed portion of the first side face 102, to provide a gap for hot air to escape from the enclosure 100 even if two such enclosures are provided directly side-by-side, or if the first side face 102 is mounted against a surface. This is described further in co-pending GB patent application number 1205781.6, in the name of Control Techniques Ltd, the entirety of which is incorporated herein by reference.

Although not shown in FIG. 1, additional vents may be provided in the enclosure 100. For example, a vent may be provided on a second side face, on the top face and/or on the rear face of the enclosure 100. Such a vent may be provided in a cut-out or recessed portion of the enclosure 100. Such vents may include slats or louvers such as those shown as part of the vent 108 in FIG. 1, to at least partially cover respective openings in the vent, to reduce contamination risks for the components within the drive unit.

The rear face 104 of the enclosure 100 is not flat or planar. Instead, there is a rearmost portion 110 (shown as the lower left-hand section of the rear face 104 in FIG. 1), which projects rearwardly of the other parts of the rear face 104. To the right of that rearmost portion 110 in FIG. 1 there is a lower recessed portion 112 and, upward of the rearmost 110 and lower recessed 112 portions, there is an upper recessed portion 114 of the rear face 104. The upper recessed portion extends the width of the rear face 104 of the enclosure 100 in FIG. 1. It is not essential that the rear face of the enclosure 100 looks exactly like the particular rear face 104 which is shown in FIG. 1 herein. However it is preferable that the rear face of the enclosure 100 comprises at least one recessed portion, to facilitate mounting of the enclosure 100 to a DIN rail or other structure, as will be understood further from the description below.

A clip 116 is provided projecting from the rear face 104 of the enclosure 100. In the embodiment shown in FIG. 1, the clip 116 is located between the lower recessed portion 112 and the upper recessed portion 114 of the rear face 104. It is not essential that the clip 116 is located exactly as shown in FIG. 1. However the clip 116 should preferably project from a part of the rear face 104 other than its rearmost portion 110, so that the size of the clip 116 itself does not add to the depth of the enclosure 100 from rear to front, or at least so that it adds to that depth as little as possible.

In practice, the DIN rail will normally sit on a flat substantially vertical surface. When the enclosure 100 is to be mounted on the DIN rail, the rearmost portion 110 of the enclosure will also sit against that surface. The DIN rail itself will be accommodated by a recessed portion at the rear of the enclosure 100. In the embodiment shown in FIG. 1, the DIN rail can be accommodated by the upper recessed portion 114. There is an overhang or hook 118 shown above the recessed portion 114 in FIG. 1, which can latch onto an upper part of the DIN rail. The clip 116 can then snap onto a lower edge of the DIN rail. As a result, the DIN rail will be securely located between the hook 118 and the clip 116, and the enclosure 100 will therefore be securely attached, with its rearmost portion 110 substantially flat against the surface from which the DIN rail itself projects (which might be a wall or the face of an equipment cabinet as discussed above).

The hook 118 may be a single continuous formation extending substantially along the width of the rear face 104 of the enclosure 100 as shown in FIG. 1. Alternatively it may extend only across a part of the width of the rear of the enclosure 100. Alternatively or additionally, a plurality of hooks may be provided for engaging with a top part of a DIN rail. The hook 118 or hooks is/are preferably formed as an integral part of the rear face 104 of the enclosure 100, as shown in FIG. 1. However it may be possible for the hook 118 or hooks to instead to be separable from the main body of the enclosure 100, for example for ease and safety of packaging and/or transport of the drive unit.

The cross-sectional shape of the hook 118 should be chosen to cooperate with the cross-sectional shape of the upper part of the DIN rail with which it engages. The shape and size of the hook 118 and its location relative to other parts of the enclosure 100 should preferably be chosen to enable the hook 118 (in conjunction with the clip 116, discussed further below) to form a reliable and secure attachment between the enclosure 100 and the DIN rail.

The clip 116 projects substantially perpendicularly from the rear face 104 of the enclosure, such that in most cases it will comprise a substantially horizontal projection when the drive unit is mounted to a DIN rail or other structure. The clip 116 is preferably formed as an integral part of the rear face 104 of the enclosure 100, as shown in FIG. 1. However it is possible for the clip to instead be separable from the main body of the enclosure 100, for example for ease and safety of packaging and/or transport of the drive unit. If the clip is separable from the main body of the enclosure, it should attach securely thereto by any suitable means, for example a push fit or snap fit, preferably without the need for fixing means such as screws or bolts.

The cross sectional shape of the clip 116 should be chosen to cooperate with the cross sectional shape of (at least part of) the DIN rail or other structure to which the drive unit is to be mounted. In FIG. 1 the free end of the clip 116, distal to the part of the rear face 104 from which the clip 116 projects, is wedge-shaped. This allows the clip 116 to form a snap-fit attachment with part of a DIN rail, to lock the drive unit in place.

In operation, the user can slide or push the drive unit laterally towards the DIN rail, after lining up the hook 118 and/or clip 116 with part of the DIN rail as appropriate, and the hook 118 and/or clip 116 will engage with the DIN rail in order to securely mount the enclosure 100 on the DIN rail. In some cases, the user may have to locate the hook 118 onto an upper part of the DIN rail before then moving the body of the enclosure 100 towards the DIN rail in order to fit the clip 116 in place at a lower part of the DIN rail and thereby secure the enclosure 100 thereto. Alternatively, it some cases it may be preferable to first engage the clip 116 with the DIN rail and then to push or pivot the enclosure 100 in order to engage the hook 118 with the upper part of the DIN rail as well.

Because of the wedge shape of the free end of the clip 116, the drive unit cannot be detached from the DIN rail merely by lateral movement in a direction away from the DIN rail. Nor will the drive unit detach from the DIN rail if it is knocked or vibrated during normal operation. The hook 118 can also help prevent detachment of the enclosure 100 from the DIN rail by lateral movement or accidental force. Therefore the drive mount is firmly attached to the DIN rail.

The clip 116 and hook 118 can be formed from any suitable material. For example either the clip 116 and/or the hook 118 may be formed from thermoplastics or thermosetting plastics. According to an embodiment, the clip 116 is formed from polycarbonate and acrylonitrlie butadiene styrene polymer (PC/ABS). Both the clip 116 and the hook 118 should be strong and sufficiently rigid that they will not sag significantly or snap under the weight of the drive unit. However at least the clip 116 (and preferably also the hook 118) should have some flexibility so that it can be deflected by the user—for example using a screwdriver or other simple tool—in order to release the free end of the clip 116 from engagement with the DIN rail, and thereby to dismount the drive unit in a quick and straightforward manner.

As mentioned above, it is preferable that the clip 116 and hook 118 project from a recessed portion or portions of the rear face 104 of the enclosure, so that their presence per se does not add significantly to the depth of the drive unit, and therefore enables it to be mounted to a DIN rail securely and compactly. It has been recognised herein that a number of design choices can be made for a drive unit—either one such choice on its own or a number of such choices in combination—in order to enable part of the rear face 104 of the drive unit enclosure 100 to be recessed, and thereby to provide space for the clip 116 and hook 118. For example, intelligent ducting of air within a drive unit can be employed in order to safely reduce the space needed for housing all its internal components.

As will be appreciated by the skilled reader, certain components within a drive unit are sensitive and have to be protected from contamination in order to function correctly. Conventionally, this has required such sensitive components to be located away from air flows—for example away from air flows between heat generating components inside a drive unit and vents on the surface of the drive unit—which has made it impossible to locate all the components within a drive unit compactly.

According to an embodiment, it is possible to provide a mechanical barrier device for protecting sensitive components within a drive unit in a straightforward and compact manner. Such a device is described in more detail in co-pending GB patent application number 1117481.0, in the name of Control Techniques Ltd, the entirety of which is incorporated herein by reference. In general, the mechanical barrier device can comprise any suitable combination of physical features such as walls, enclosures, covers, baffles, openings or ducts in order for the device to be fitted around, over and/or in between electronic components which are to be protected. The device can provide a physical barrier for protecting electronic circuitry from potentially contaminated air. In addition to providing that protection, it can be used to manipulate air flow around the circuitry and/or to provide a mechanical connection between, or location of, cooling devices such as heat sinks and the electronic circuitry.

The above-mentioned mechanical barrier device can be used to allow an electronic circuit to be cooled by air whilst at the same time protecting that circuit from both physical and chemical contamination. It can do this by including gaps or air holes at select locations, if the components at those locations are not particularly sensitive to contamination, to allow air to directly touch those locations. Alternatively or additionally, openings can be included to allow cooling devices such as heat sinks to protrude therethrough, wherein those cooling devices extend from electronic components that require cooling but are potentially sensitive to contamination. The cooling devices are air cooled, instead of directly cooling the sensitive electronic component(s). As a result, air can still flow around or through areas of the electronic circuitry, or to cooling devices connected thereto, in order to cool the electric components during operation but at the same time not cause physical or chemical contamination to the circuit. The mechanical barrier device can include walls which provide electrical and/or thermal isolation between circuit components. It can also include holes or recesses which components can fit into or through. It can thus act as a locating means for those components, and can mechanically link them to other features such as a PCB.

When a drive unit includes a mechanical barrier device as described above, it is possible for its internal components to be arranged differently—usually more compactly—than has previously been possible for conventional drive units. As a result, the enclosure for the drive unit can be more compact. In particular, the enclosure may include one or more recessed portions, as shown and described with respect to the improved enclosure 100 of FIG. 1 herein.

According to an embodiment, intelligent venting can be used in order to make an enclosure for a drive unit more compact, and to introduce greater freedom as to the shape of the enclosure. Therefore such intelligent venting can help enable the provision of a recessed portion of a face of the enclosure—such as its rear face—which an integral clip and/or hook can project from. This intelligent venting is described further in co-pending GB patent application number 1205781.6, in the name of Control Techniques Ltd, the entirety of which is incorporated herein by reference. In general, one or more vents can be provided on a side face or on the rear face of the enclosure, or on a plurality of such faces.

Improved distribution and use of cooling components such as heat sinks within a drive unit can also be used to facilitate the creation of recesses in the enclosure 100. This can work in conjunction with intelligent venting. Providing more than one vent on a surface of the enclosure makes the option of using several heat sinks at different locations within a drive unit more realisable, rather than being restricted to one heat sink common to all heat generating components, as has been used in the past. Each of these heat sinks can preferably be smaller than the type of heat sink used in prior art drive units. This potential to use multiple smaller heat sinks provides a greater degree of freedom with respect to the selection and arrangement of components within the drive unit, which leads to a greater flexibility with respect to the size and shape of the enclosure housing those components. For example, because all of the heat generating components are not restricted to being in a linear arrangement at one part of the drive unit, certain of the components in the drive unit can instead be relocated in order to better distribute the airflow within the drive unit, and to make better and more compact use of the space within the enclosure.

Whilst particular embodiments have been shown and described herein, variations can be made thereon. For example, the improved enclosure may be implemented for other types of device, not just for a drive unit. The clip and/or hook may project from any face of the enclosure, not just from the rear face. The clip and/or hook need not project from a recessed part of a face the enclosure. They may instead project from the outermost part of that face, or from any part of a substantially planar face of the enclosure. The clip and hook have been described as being compatible with a DIN rail. They can be compatible with any size or type of DIN rail, or with another sort of rail or structure to which the enclosure is to be mounted. The enclosure may comprise more than one clip and/or more than one hook. For example it may comprise two or more clips on the same face of the enclosure and/or a respective clip may be provided on each of two or more different faces of an enclosure.

The term “clip” has been used herein to describe a projection from a face of the enclosure that enables it to be mounted to a DIN rail. However any other suitable term may be used instead for this feature.

The term “hook” has been used to describe a projection from an upper part of a face of the enclosure that works with the clip in order to enable the enclosure to be mounted to a DIN rail. However, as described above, this feature does not have to be a hook per se and any other suitable term may be used instead for this feature. According to an embodiment, the hook may be absent and the enclosure may simply engage with a structure via the clip.

Terms such as “front”, “rear”, “side”, “top”, “bottom”, “upper”, “lower”, “rearward”, “outer”, “vertical” and “horizontal” have been used herein with respect to the figures for illustrative purposes only. These terms are not intended to be limiting.

Claims

1. An enclosure for a drive unit, said enclosure having a plurality of faces and being arranged to house components, wherein a first face of said plurality of faces comprises an outer portion and at least one recessed portion and wherein a first projection is provided projecting from a recessed portion of the first face, said first projection being arranged for engagement with a structure to which the enclosure is to be mounted.

2. An enclosure as claimed in claim 1 further comprising a second projection projecting from a recessed portion of the first face, said second projection also being arranged for engagement with a structure to which the enclosure is to be mounted.

3. An enclosure as claimed in claim 2 wherein the first and second projections project from first and second respective parts of the same recessed portion of the first face.

4. An enclosure as claimed in claim 2 wherein the first and second projections are arranged for location of at least part of the structure to which the enclosure is to be mounted therebetween.

5. An enclosure as claimed in claim 1 wherein said first projection is integral to said first face.

6. An enclosure as claimed in claim 2 wherein said second projection is integral to said first face.

7. An enclosure as claimed in claim 1 wherein the first projection comprises a free end, distal to the respective recessed portion, wherein said free end does not extend outwards of the outer portion of the first face.

8. An enclosure as claimed in claim 2 wherein the second projection comprises an outer surface, distal to the respective recessed portion, and wherein said outer surface does not extend outwards of the outer portion of the first face.

9. An enclosure as claimed in claim 1 wherein the first projection comprises a clip.

10. An enclosure as claimed in claim 2 wherein the second projection comprises a hook.

11. An enclosure as claimed in claim 1 further comprising at least one vent provided on a face thereof.

12. An enclosure as claimed in claim 1 wherein the enclosure houses at least one cooling component.

13. An enclosure as claimed in claim 12 wherein said cooling component comprises a heatsink.

14. An enclosure as claimed in claim 1 wherein the enclosure houses an electronic circuit and an apparatus for protecting said electronic circuit from an airflow, said apparatus comprising a cover means for covering at least part of the electronic circuit and a guide means for guiding an airflow around the electronic circuit.

15. An enclosure as claimed in claim 1 wherein the structure to which the enclosure is to be mounted comprises a DIN rail.

16. An enclosure as claimed in claim 1 wherein said first face comprises a rear face of the enclosure.

17. An enclosure as claimed in claim 1 wherein said enclosure is arranged to house heat generating components.

18. (canceled)