AN AUDIO RECORDING DEVICE

Abstract: An audio recording device for use in covert operations comprises a casing consisting of a tray (51) with a hinged lid (57). A printed circuit board (53) is fitted into the tray (51). The board (53) has a window (77) in which a pair of batteries (87) are fitted, a connection for a microphone, and a connection for a replaceable semiconductor memory card (89). The card (89) is inserted into the casing from the end remote from the hinge (98) of the lid (57) by being slid into a slideway so that it lies parallel to and adjacent the printed circuit board (53). The lid (57) encloses the batteries (87) and the card (89) when it is closed, the batteries (87) and the card (89) being accessed for replacement merely by opening the lid (57).

Description: AN AUDIO RECORDING DEVICE This invention relates to an audio recording device. There are presently many types of portable battery powered audio recording devices on the market. These include small pocket devices for storing recorded messages to be played back. FR-A-2692710 discloses one such device which is about the size of a credit card and which comprises a two part casing which contains a battery powered circuit on a printed circuit board, including the batteries, a microphone which is connected to the circuit and a memory which is incorporated in the circuit and in which the messages are stored for playing back. Cards including a memory store to retain audio information picked up by a microphone, for playing back have also been proposed. EP-A-0 277 276 and EP-A- 0 394 573 disclose such devices. In general, these devices can only store short messages. Hence, they are not practical for use when it is required to record over a long period of time. The recording medium used in devices which record over a long period of time has usually been magnetic tape. The size of such audio recording devices is determined by the size of the tape used, the size of the motor required to drive the tape, the circuitry required to control the operation of the device, the size of the batteries required and the relative locations of these components in the assembled device. Such audio recording devices presently available are relatively large and can be difficult to conceal, thereby posing difficulties in covert operations. A further disadvantage is that in most such devices changing the tape and/or the battery is time consuming and cumbersome, again posing problems in covert operations. Also, since such devices need a motor and other moving parts to record audio signals the device reliability is sometimes not sufficient for use in surveillance operations. An object of this invention is to provide an audio recording device which can be used to record over a long period of time, which is portable, small and light and can be easily concealed, whilst being robust and reliable. A further object of the invention is to provide an audio recording device which can be prepared for use quickly and discreetly. According to the invention there is provided an audio recording device as claimed in claim 1. Preferred features of the device are claimed in claims 2 to 5. A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings, of which; Figure 1 is a plan view of an audio recording device with part of its cover broken away to reveal some of the interior of the device; Figure 2 is a section on the line II - II in Figure 1; Figure 3 is a section similar to Figure 2 but with the cover open and illustrating replacement of replaceable elements; and Figure 4 is a view in the direction of arrow IV in Figure 2 with the cover in the open position shown in Figure 3. Figures 1 to 4 show an audio recording device which comprises a tray 51, a printed circuit board 53, a dividing section 55 and a cover 57. The tray 51 comprises a generally rectangular base with a lip formed around its periphery. The printed circuit board 53 is fitted into the tray 51. It is substantially rectangular in shape with an oblong window 77 formed at one end. It is shaped so that its edges abut the lip of the tray 51 on both of the long sides and the short side which is nearer the window 77. The printed circuit board 53 is supported on upstanding projections formed in the tray 51, thereby providing clearance for electrical components (including integrated circuits) on the underside of the board 53. The printed circuit board 53 is provided at the end nearer to the window 77 with a connector 81 for a microphone 82. There is a connector 83 for a memory card on the opposite side of the window 77 and connectors 85 for two batteries 87 at the sides of the window 77. Printed circuit paths for interconnecting the connectors 81, 83, 85 and 87 are formed in the narrow parts of the board 53 along the shorter sides of the window 77, as well as on the remainder of the board 53. The window 77 is sized to accommodate the batteries 87. The type of battery 87 currently being used is an AAA-type. The generally rectangular dividing section 55 fits onto the tray 51 so that the printed circuit board 53 is sandwiched between them as can be seen from Figures 2 and 3. It is provided with a series of retainers which ensure that when it is fitted, the various components of the assembled device are held in place. The dividing section 55 has a rectangular window 94 nearer to one of its ends. The window 94 is substantially superimposed over the window 77 in the printed circuit board 53. Figures 2 and 3 show that two walls 100 and 101 depend one from each of the long edges of the window 94. These walls 100 and 101 pass through the window 77 in the printed circuit board 53. The dividing section 55 is formed with side walls 97 along each of its longitudinal sides. A substantially U shaped shelf 93 is formed between the window 94 and the other end of the dividing section 55 that is further from the window 94. An angled bar 95 extends between the side walls 97 at that other end with a portion 104 of it depending. The angled bar 95 is in the region of and below the mouth of the U shaped shelf 93. Parts 97A of the side walls 97 depend further than the remainder. These parts 97A depend from the side portions of U shaped shelf and extend along the edge of the dividing section 55 from the angled bar 95 and towards the window 94. These side wall portions 97A terminate spaced from the depending wall 101. The depending walls 100 and 101, the depending portion 104 of the angled bar 95 and the depending side wall parts 97A rest on the base of the tray 51. The depth of the depending portion 104 is about half that of the walls 100 and 101 so that the other portion of the angled bar 95 is nearer to the base of the tray 51 than is the U shaped shelf and there is a clearance therebetween. There are upstanding side wall portions 91 all along the sides of the dividing section 55. These side wall portions 91 extend above the shelf 93. Threaded holes that are provided in the dividing section 55 correspond to holes formed in the tray 51 whereby the two parts are screwed together. A hinge pin fixing arrangement 98 is provided at the end of the dividing section 55 nearer the window 94. When the dividing section 55 is fitted to the tray 51, the first and second depending walls 100 and 101 slot into the window 77 in the printed circuit board 53 so that the area of the printed circuit board 53 surrounding that window 77, including the connector 83 for the semiconductor memory card 89, is effectively covered and thereby protected. The dimensions are chosen so that, when the batteries 87 are put in place they are a snug fit in the window formed by the depending walls 100 and 101. The angled bar 95 covers and protects a button and spring latching arrangement 71 which is fitted to the tray 51. The assembly of the device is completed by fitting the cover 57 to the dividing section 55 using a hinge with a hinge pin that is fitted to the hinge pin fixing arrangement 98. The dimensions of the cover 57 are such that when it is in its closed position it extends between the upstanding sidewall portions 91, and rests on the U- shaped shelf so that a cavity 113, is formed between the printed circuit board 53, the dividing section 55 and the cover 57 to one side of the window 77. The cavity 113 accommodates the semiconductor 89 card when the device is being used, the card 89 lying parallel to and adjacent to the printed circuit board 53 (see Figure 3). The cover 57 is held closed using the button and spring arrangement. To assemble the device, the printed circuit board 53, with the various connectors fitted thereon, is fastened to the tray 51 and the button and spring arrangement 71 is fitted so that the actuating buttons are on the outside of the tray 51. The dividing section 55 is then fitted to the tray 51, by screwing the two parts together, and the cover 57 is fitted. The device is then ready for use, and requires only that batteries and a semiconductor memory card 89 be fitted into place. The assembled device is very compact. To fit or replace a memory card 89 and batteries 87, the cover 57 is opened (as shown in Figures 3 and 4), the card 89 is slid in from the end of the device remote from the cover hinge pin arrangement 98, above the angled bar 95 and below the shelf 93 to plug it into the connector 83 (see Figure 3). The batteries 87 are inserted into the window 94 between the depending walls 100 and 101 to make contact with the terminals 85 on the printed circuit board 53. The cover 57 is closed. The mouth of the slideway for the card is closed by the securing lip 109 of the cover 57 and the remainder of the cover 57 encloses the interior of the device including the battery well. The thickness of the device is governed by the diameter of the batteries 87, since the thickness of the memory card 89 and the printed circuit board 53 together is less than the diameter of the batteries 87 with which they are aligned generally radially. The audio recording device described herein is, relative to present day audio recorders, very light and small and can be easily concealed. The provision of a cover which can be easily opened to access the batteries and the semiconductor card areas simultaneously means that the device can be prepared for use quickly and discreetly.

Claims: £ &---_ 1. An audio recording device comprising a casing containing a circuit adapted to be powered by at least one battery, said circuit having connecting means to enable a microphone to be connected, and there being space within the casing to accomodate the or each battery when it is connected to said circuit to power it, characterised in that further connecting means are provided which are operable to connect with a semiconductor memory card, there being space within the casing to accommodate the memory card when it is so connected, the memory card being replaceable, the device being arranged so that when a semiconductor memory card, said at least one battery and the microphone are connected to the circuit, audio signals received by the microphone are recorded on said semiconductor memory card. 2. An audio recording device according to claim 1, wherein the casing is provided with a lid whereby the or each battery and the semiconductor card can each be accessed for replacement by merely opening the lid. 3. An audio recording device according to claim 1 or claim 2, wherein the circuit is provided on a printed circuit board. 4. An audio recording device according to claim 3 wherein the printed circuit board is provided with an aperture to accommodate the or each battery, and the connecting means for the semiconductor memory card are mounted on the board to receive the semiconductor memory card which is orientated and supported parallel to and adjacent the board. 5. An audio recording device according to any of the preceding claims in which the batteries are of the AAA type.

Inventors: JONES MICHAEL JOHN, JONES, MICHAEL, JOHN
Applicants: AIT RECORDERS LTD, JONES MICHAEL JOHN, A I T RECORDERS LIMITED, JONES, MICHAEL, JOHN
Application year: 1995
Main classification: G11C7
IPC codes: G11C5, G11C7, H01M2, H05K1