WO2002091467A2

WO2002091467A2 - Protective housing for memory

Info

Publication number: WO2002091467A2
Application number: PCT/GB2002/002037
Authority: WO
Inventors: John Theobald
Original assignee: Qinetiq Limited
Priority date: 2001-05-10
Filing date: 2002-05-07
Publication date: 2002-11-14
Also published as: AU2002255139A1; WO2002091467A3; GB0111531D0

Abstract

A protective housing for a memory device or data logger device of the button memory type, comprises a base plate having means associated therewith for locating the device and for providing an electrical contact between a first outer portion of the device and the base plate, one or more wall elements upstanding from the base plate and a top plate attached to said wall elements and lying in a substantially parallel plane to the base plate, the base plate, top plate and wall elements providing a substantially complete enclosure around the device, and having an optionally closable aperture for allowing electrical contact to be made by an external probe with both the base plate and with at least one further outer portion of the device for the purpose of downloading data therefrom. Guidance means are provided to ensure positive location of the probe within the housing so that the correct contacts are made with the device read-out areas.

Description

Protective Housing

This invention relates to memory devices and data loggers of the button type and more particularly to a protective housing for such data loggers.

"Button memory" (also known as "contact memory") is the term which is used to describe a class of electronic devices containing read only and/or read/write memory housed in a robust button shaped canister. Data from the memory can be read by means of a probe which makes contact with selected locations on the outside of the button memory canister. Commonly there are at least two and often three separate outputs from the button memory which are read through a like number of separate contacts on the probe. This method of downloading data has the advantage of enhanced security because the devices cannot be read from a distance but it does mean that the button memory must be accessible from above, the probe being designed to simultaneously make contact with two or more separate areas on the top surface of the button memory canister.

Munitions are often stored over long peri'ods of time and during that time may be moved to various locations at different times. The materials used within munitions and in particular the explosives and pyrotechnic materials content of munitions are recognised as having a finite lifetime. It is also the case that rate at which such materials age is strongly dependent upon environmental factors such as the humidity and temperatures to which they are subjected over uieir lifetime. It has been usual practice to assume that a particular munition would be subject to a pre-defined range of temperatures and humidities over its life and a safe lifetime then calculated on that basis. In order to allow a margin of safety the lifetime calculated in this way will generally be a rather conservative figure and although it has been common practice to examine and test munitions which are close to their calculated life expiry in order to establish whether their lifetime may be extended, this is a time consuming process and still permits some uncertainty since it must be done on a sampling basis. In many cases it is however found that the lifetime can be safely extended. It will be appreciated then that the need to allow for a wide margin of safety in the face of uncertain conditions of future storage means that the life set for many munitions will actually be significantly shorter than it need be and hence they may be replaced prematurely at considerable expense. Consequently it would be useful to be able to track the temperatures to which munitions have actually been subject over an extended period of time and it has been proposed that this could be done using certain button memory devices which possess a temperature logging capability.

Some of these devices, however, such as those produced by Dallas Semiconductor under the name "iButtons", are powered by batteries and although the logger canisters are reasonably robust, the juxtaposition of a battery with a munition requires that the two should be protectively separated so as to ensure that mechanical damage to the device is prevented as far as possible to avoid any possible malfunction of the batteries. It is particularly important to ensure a high degree of separation in the case where lithium batteries are used on account of the high energy density a d low internal resistance possessed by this type of battery, making them especially incompatible with munitions. The Dallas memory devices are, for example, powered by lithium batteries.

Consequently it is an object of the present invention to provide a secure protective housing for a data logger of the button memory type whilst yet allowing appropriate access to the logger for read out purposes.

Accordingly, the present invention provides a protective housing for a memory device or data logger device of the button memory type, which comprises a base plate having means associated therewith for locating the device and for providing an electrical contact between a first outer portion of the said device and the base plate, one or more wall elements upstanding from the base plate and a top plate attached to said wall elements and lying in a plane which is substantially parallel to the base plate, said base plate, top plate and wall elements providing a substantially complete enclosure around the device, and further comprising means for allowing electrical contact to be made by external probe means with both the base plate and with at least one further outer portion of the device for the purpose of downloading data from the device.

The first outer portion of the logger or memory device is usually a peripheral area of the device such as the outer circumference of the device. This may be associated with a circumferential flange which is arranged to sit on the base plate of the housing.

The means for allowing electrical contact to be made directly with the data logger device or memory device will generally comprise an aperture in either the wall(s) or the top plate, most preferably the former as this provides the best protection to the logger or memory device, together with guidance means interactive with an external probe for ensuring contact between said probe and those outer portions of the data logger or memory device through which data downloading is to be effected.

The guidance means may typically comprise one or more elements defining a channel associated with the housing and located adjacent the aperture, which channel is adapted to receive a probe in a relatively tight-fitting manner so as to ensure that the probe, on being introduced through the aperture in the housing, is constrained by the guidance means in such manner that one or more contact areas on the probe is necessarily brought into contact with the said at least one further outer portion of the logger device as well as ensuring contact of the probe with the base plate (or with a part of the housing in electrical continuity therewith such as the walls of the housing or a separate guidance means if provided). It will be appreciated that those parts of the probe which respectively contact the base plate and the at least one further outer portion of the logger device should be insulated from each other in order that separate electrical paths from respective outer portions of the logger device via the probe to a data storage and display system are provided.

Typically the probe will have resilient contact areas located such that they lie adjacent to, and are biased to make contact with, the defined contact areas on the logger or memory device once the probe is fully located within the housing as well as making contact with the base plate or other part of the housing in electrical contact therewith. In the simplest form of probe, these areas and the electrical paths extending theref om are insulated from the main body of the probe which is made of a metallic material and which is therefore able to act as a further contact area for making contact with a metallic base plate of the housing or with some other part of the housing which is electrically conductive and is in contact with the base plate such as, especially, the guidance elements, as previously described.

Downloading from the button memory or logger devices generally requires a fairly high degree of precision in the placement of the contact areas on the probe since the areas on the device which are to be contacted are relatively small. Typically such a device has an upper surface which measures 15mm or less and may comprise two concentric zones separated from each other by insulation, the outer zone being likewise separated from the peripheral portion of the device by a further ring of insulating material. The central area may thus be only 2 or 3mm across and separate contacts have to be made with each of these areas by different contact areas of the probe. Consequently these latter contact areas will normally be in the nature of point contacts and the housing will advantageously have a stop means arranged to provide precise location of the probe within the housing and ensure correct contacts between respective areas on the probe and on the device.

Conveniently, the housing is in the form of a rectangular box, with one side or a part thereof, being left open and adapted to accept a probe device being passed through the opening to contact the data logger, as abovernentioned. Alternatively, the housing may be of a generally cylindrical or polygonal form with an aperture in the side wall and guidance means disposed co-operatively with the aperture in such manner as to guide suitable contact areas on a probe inserted through the aperture and into the housing into contact with the relevant portions of the logger device. Preferably, for robustness, the guidance means is located within the housing but it could be external to the housing if desired.

Advantageously, to provide total enclosure of the logger or memory device from its surroundings (except when downloading is taking place), the aperture is fitted with a sliding door or other form of closure which can be opened when required in order to introduce the probe to the device but which is otherwise biased towards or is locked in the closed position. If there is no protective closure to the aperture a barrier of suitable form may be attached to the base plate so as to surround the logger device and so protect it from damage from any object which may inadvertently enter through the aperture.

In that instance the means provided within the housing for accomodating the logger or memory device may comprise in effect such a barrier but alternatively either a recess formed in the base plate which is sized so as to provide a tight fit for the device or one or more wall portions upstanding from the base plate and sized to allow the device to be inserted between them and be retained thereby may be provided. Most preferably, these wall portions will be formed of a springy material to firmly retain the device in place. Alternatively, where the device has a circumferential flange, this can be gripped by spring clips which are fixed to the base plate. In all cases, by providing that the means for retaining the device is made of an electrically conducting material and is electrically coupled to the housing, a circuit from a first outer (peripheral) portion of the device to the probe can be ensured for use when downloading data from the logger or memory device.

The invention will now be further described by way of example only with reference to the following figures of the accompanying drawings, of which;

Figure 1 shows in a three dimensional view and partially cut away, a first embodiment of a housing according to the invention;

Figure 2 shows a second embodiment of a housing according to the invention in plan view from above and with the top plate removed.

In Figure 1 there is shown generally at 1 a housing in the form of a rectangular box. The housing comprises a base member 2, walls 3a, 3b and 3c and a top plate 4. The fourth side of the rectangular box is open and allows the logger device 5, located within the box, to be seen. The lower part of the logger device is located in a recess 6 which is formed in a separate locating member 7 which is fixed to the base plate 2. The locating member also serves^'to provide further protection to the logger device and can either wholly or only partially surround the logger as desired.

The housing 1 is conveniently made from a metallic material such as steel or aluminium. Where an electrically non-conductive material is used instead an electrically conducting path will have to be laid down from a point of contact with a first portion of the outside of the logger device to a location at which contact can be made with the path by the probe when it is introduced into the logger housing.

In the second embodiment of a housing according to the invention shown in Figure 2, like numerals represent like parts of the housing 1. In this embodiment the housing is circular with a continuous wall 3. Logger device 5 is located and retained on base plate 2 by three upstanding clip members 8 which also provide electrical connection between an outer portion of the logger device and base plate 2. Shown generally at 9 is an opening in wall 3. As shown in Figure 2, opening 9 is closed by a shutter 0 which is movable (using handle 11) around the perimeter of wall 3 in the region 13 in order to expose the opening and enable a probe to be inserted into the housing to contact the logger for purpose of downloading data therefrom. Conveniently the shutter will be retained by channels 12 formed on the base plate and the top plate (not shown) which allow the shutter to be pushed behind wall 3 in the region 11. Finally, shown at 14, are two L-section guide members which will direct a probe introduced through opening 9 so as to ensure that proper electrical contact is made between the top of the logger device and one or more contact areas located on the underside of the probe. At least one of the guide members 14 is in electrical contact with the base plate and hence will allow the body of the probe to be used as a further contact area for downloading information via the periphery of the logger or memory device. Once the probe has been withdrawn from the housing, the shutter can be closed either manually or automatically by a spring-loaded bias device (not shown).

Other alternative arrangements of the above-described elements of the housing of this invention will be readily apparent to the skilled person and are contemplated to be within the scope of the invention.

Claims

1. A protective housing for a memory device or data logger device of the button memory type, which comprises a base plate having means associated therewith for locating a logger or memory device and capable of providing an electrical contact between a first outer portion of said device and the base plate, one or more wall elements upstanding from the base plate and a top plate attached to said wall elements and lying in a plane substantially parallel to the base plate, said base plate, top plate and wall elements providing a substantially complete enclosure around the device, and further comprising means for allowing electrical contact to be made by external probe means with both the base plate and with the at least one further outer portion of the device for the purpose of downloading data therefrom.

2. A protective housing as claimed in claim 1 wherein the means for allowing electrical contact to be made directly with a memory device or data logger device located therein comprises an aperture in either the wall element(s) or the top plate through which an external probe can be inserted into the housing and guidance means located adjacent to the aperture for guiding said probe so as to ensure that contact is made between respective outer portions of the device and contact areas on the probe for the purpose of effecting data downloading.

3. A protective housing as claimed in claim 2 wherein the guidance means comprises one or more elements defining a channel and extending within the housing inwardly from adjacent to the aperture which channel is adapted to receive a probe in a relatively tight- fitting mariner so as to ensure that the probe, on being introduced through the aperture in the housing, is constrained by the channel in such manner that one or more contact areas on the probe are necessarily brought into contact with the at least one further outer portion of a device located within the housing, as well as ensuring contact of the probe with the base plate.

4. A protective housing as claimed in claim 3 wherein the guidance elements within the housing are electrically connected to the base plate so as to provide the required electrical contact between the base plate and the probe.

5. A protective housing as claimed in claim 4 wherein the guidance elements are comprised by two of the wall elements which lie parallel to one another and which are electrically connected to the base plate.

6. A protective housing as claimed in any one of claims 1 to 5, which further comprises stop means located so as to provide a positive location for an external probe which has been introduced into the housing.

7. A protective housing as claimed in any one of claims 2 to 6, wherein the aperture is closable with a shutter.

8. A protective housing substantially as described herein and with reference to the drawings.

9. Apparatus for use with a memory or data logger device which comprises a protective housing for the device and a separate probe which is adapted to interface with said housing and with a device located within said housing in order to effect downloading of data from the device.

10. Apparatus as claimed in claim 9, wherein the housing is according to any of claims 1 to