GB2347894A - Keypad locking mechanism for mobile phone using a slidable locking plate - Google Patents

Abstract

The keypad includes a locking plate 1 which is movable, via a sliding switch 15, from a disengaged position (Fig.1) in which each key 5 is free to move, to an engaged position (Fig.2) in which depression of at least some of the keys is restrained. The plate and at least some of the keys are provided with cooperating formations 7,9, in the form of a pin and a recess respectively, which in an engaged position of the locking plate are interconnected to restrain the movement of the keys. The locking plate may be formed with alternative locking arrangements, for example, "keyhole" shaped openings (103,Fig.6) or parallel elongate openings (Fig.10). The locking mechanism may be used with other portable apparatus, for example, a personal organiser or calculator.

Description

MECHANICAL LOCK FOR~KEYPAD APPARATUS The invention relates to a mechanical lock for a keypad apparatus, and in particular, to a mechanical lock for the keypad of a mobile telephone.

BACKGROUND By their very nature, mobile phones are often stored in peoples'pockets or handbags when not being used. This means that they can be activated in error if something accidentally presses-against the button used to switch on the phone. This can lead to the mobile phone's battery being drained unnecessarily.

Some mobile phones overcome this problem to a certain degree by using an electronic lock feature.

This locks the keypad and causes the keypad driver to ignore button presses, unless the unlock PIN (Personal Identification Number) is entered. For safety reasons, phones having an electronic lock feature such as this still allow emergency numbers to be dialled.

Therefore, even phones having electronic locks could be accidentally activated if the sequence of numbers 999, or the PIN numbers were pressed inadvertently. In the case of emergency numbers, this has the added disadvantage of tying up an emergency line, in addition to draining the battery power of the phone.

Furthermore, in order to avoid the cumbersome task of entering the PIN number each time the mobile phone is used, many users of phones having electronic locks do not activate the electronic lock feature every time the, mobile phone is stored, which increases the probability of activating the phone by mistake.

The aim of the present invention is to overcome the disadvantages mentioned above by having a mechanical lock feature for a keypad apparatus.

SUMMARY OF THE INVENTION According to a first aspect of the present invention there is provided a keypad comprising: a plurality of depressable keys; and a locking member movable from a disengaged position in which each key is free to move, to an engaged position in which depression of at least some of the keys is restrained, the locking member and at least some of the keys being provided with cooperating formations, which in an engaged position of the locking member are interconnected to restrain the movement of the = Preferably the locking member is movable into a plurality of positions in which different combinations of keys are locked or unlocked. For example, the locking member may be movable from a disengaged position in which all of the keys are free to move, to a first engaged position in which the movement of a first combination of keys is restrained or to a second engaged position in which the movement of a second combination of keys is restrained.

Preferably the locking member comprises a plate having a plurality of openings, each opening being associated with and accommodating a respective key or a respective group of keys.

Preferably, the cooperating formations comprises: a plurality of projections, each projection being formed on an edge of an opening and projecting inwardly of the opening; and a plurality of recesses formed in the keys, the plate being movable from the disengaged position in which the projections are withdrawn from the recesses, to the engaged position in which the projections are located in the recesses.

Preferably, the plate moves between engaged and disengaged position in a plane substantially perpendicular to the direction in which the keys are depressed.

Preferably, the plate moves between the engaged and disengaged positions on first and second tracks located on the keypad.

Each opening may be substantially the same shape as the corresponding key which it accommodates, but may be elongated in the direction in which the plate moves between the engaged and disengaged positions.

Preferably the plate has a switch for enabling the user to move the plate between the engaged and disengaged positions.

Preferably the plate is provided with means by which it can be held in the engaged and/or disengaged positions. The holding means may comprise a notch on the plate, which cooperates with one of a plurality of grooves provided on the keypad apparatus, for holding the plate in one of a plurality of predetermined positions. Alternatively, the keypad apparatus may be provided with a notch and a plurality of cooperating grooves may be formed in the plate.

Preferably, the plate is located within the casing of the keypad apparatus.

According to a second aspect of the invention there is provided a key actuated device comprising a key and an electrical contact, the key comprising a pressure surface and a body portion which transmits a force applied to the pressure surface to the electrical contact, the device further comprising a locking member which is disposed between the pressure surface and the electrical contact and which is movable from a disengaged position in which the actuating portion is free to move and an engaged position in which the movement of the actuating portion is restrained.

According to third aspect of the present invention, there is provided a keypad comprising a plurality of keys and a plurality of electrical contacts, each contact being associated with a respective key, each key comprising a pressure surface and a body portion which transmits a force applied to the pressure surface to the respective electrical contact, the keypad further comprising a locking member disposed between the pressure surfaces and the electrical contacts, the locking member being movable from a disengaged position in which each body portion is free to move and an engaged position in which movement of each body portion is restrained.

According to a fourth aspect of the present invention there is provided a keypad comprising: a plurality of depressable keys; and a locking member movable at least between a first position in which depression of a first combination of keys is prevented and a second position in which depression of a second combination of keys, different from the first combination of keys, is prevented, the locking member and at least some of the keys being provided with cooperating formations which are engagable by movement of the locking plate to selectively prevent depression of the first or the second combination of keys.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a plan view of a locking plate in the unlocked position; Figure 2 is a plan view of a locking plate in the locked position; Figure 3 is a side view of a mobile telephone having a lock switch; Figure 4 is a cross sectional view of the locking plate of Figure 1; Figure 5 is a cross sectional view of the locking plate of Figure 2.

Figure 6 is a plan view of an alternative embodiment of locking plate in the unlocked position; Figure 7 is a plan view of the locking plate of Figure 6 in the locked position; Figure 8 is a cross-sectional view of the locking plate of Figure 6; Figure 9 is a cross-sectional view of the locking plate of Figure 7 ; Figure 10 is a plan view of an alternative embodiment of locking plate, in the unlocked position; Figure 11 is a plan view of the locking plate of Figure 10 in the locked position' Figure 12 is a plan view of the locking plate of Figure 10 in a partially locked position; Figure 13 is a cross-sectional view of the locking plate of Figure 10; Figure 14 is a cross-sectional view of the locking plate of Figure 11; Figure 15 is a cross-sectional view of the locking plate of Figure 12; and Figure 16 is a side view of a mobile telephone having a three position lock switch.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION Referring to the drawings, Figure 1 shows a keypad for a mobile phone comprising a locking member or a locking plate 1, in which is formed a plurality of openings 3. Each opening 3 is shaped to accommodate a respective keypad button 5, and also comprises an inwardly projecting pin 7. A recess 9 is formed in each button 5, the recess 9 being aligned with the corresponding pin 7 on the plate 1.

When the locking plate 1 is in the unlocked position, as shown in Figure 1, each pin 7 is located away from the associated recess 9 in its corresponding button 5. Since the pin 7 does not engage with the recess 9, the button 5 can be depressed freely, to thereby make its intended electrical contact.

Figure 2 shows the locking plate 1 in the locked position. In this mode, each protruding pin 7 engages with the recess 9 in its corresponding button 5. With the locking plate in this position, the buttons 5 are restrained from being moved. This-means that the mobile phone cannot be activated inadvertently while being stored, for example, in an user's pocket or handbag.

The locking plate 1 moves between the locked and unlocked positions in a plane substantially perpendicular to the direction in which the buttons 5 are pressed. A pair of tracks 11 and 13 are provided in the locking plate 1. The tracks cooperate with corresponding formations in a casing of the mobile phone and allow the locking member to slide relative to the casing. Referring to Figure 3, a lock switch 15 is fixed directly to, or is integrally moulded with, the locking plate 1, and projects through a slot 17 formed in the side of the casing 19. A portion of the lock switch 15 projects from the casing and is therefore readily accessible to the user of the phone. In the illustrated embodiment the lock switch is positioned so that it can be slid by the user's thumb along the slot 17, thereby moving the locking plate between the locked and unlocked positions. The construction and positioning of the lock switch 15 may be varied to suit a particular application, but the direct connection of the lock switch 15 to the lock plate and/or projection of the lock switch 15 from the side of the casing simplify construction and improve the ease of operation and reliability of the locking mechanism as a whole.

Figure 4 shows a cross-sectional view of the locking mechanism in the unlocked position. The locking plate 1 has a plurality of protruding pins 7, each one aligned with a recess 9 in a corresponding button 5. If downward pressure is applied to the surface of the button 5, it is free to move downwards since the protruding pin 7 is not engaged with the recess 9 in the button 5. The button 5-is thereby free to make its intended electrical contact.

Figure 5 shows a cross-sectional-view of the invention in the locked position. In the locked position, each protruding pin 7 engages with the recess 9 in its corresponding button 5. If downward pressure is now applied to the surface of the button 5, movement of the button is restrained due to the cooperation of the protruding pin 7 and recess 9.

In order to prevent the locking plate 1 from sliding inadvertently between the locked and unlocked positions, a notch-locking mechanism is provided (as shown in Figures 4 and 5). The notch-locking mechanism comprises a notch 21 on the plate 1. The notch 21 sits into one of two grooves 23 and 25 located on the mobile phone, for holding the locking member in either the locked or unlocked position. The locking plate 1 is moved between the two positions by the user applying sufficient pressure to slide the lock switch, causing the notch to release from the groove currently being occupied.

This embodiment of the invention may be modified such that movement of the locking plate from one position to another could have the effect of locking only certain keys and/or at the same time unlocking certain other keys. This could be achieved by some of the openings on the locking plate having no protruding pin or having a protruding pin formed on an opposite end of the opening.

An alternative embodiment of the keypad is illustrated in Figures 6 to 9. In this embodiment, the locking plate 101 is also formed with a plurality of openings 103 but these openings are substantially "keyhole"shaped and comprise a larger diameter semicircular portion 102 and a smaller diameter slot shaped portion 104. The semicircular portion 102 of each opening 103 is shaped to closely receive a respective keypad button 105, whereas the slot shaped portion 104 of each opening 103 is-too narrow to accommodate the widest part of the respective keypad button 105.

A recess 109 is formed in each side of each keypad button 105. This has the effect of locally narrowing each keypad button 105 so that it is slightly narrower than the slot shaped portion 104 of the opening 103.

When the locking plate 101 is in the unlocked position, as shown in Figure 6, each keypad button 5 is located within the semicircular portion 102 of the opening 103 and hence it is free to move in a direction substantially perpendicular to the plane of the locking plate 101 and thereby depress the electrical contact lying beneath it.

The locking plate 101 is moved from the unlocked position as shown in Figure 6 to the locked position as shown in Figure 7 by sliding the locking plate 101 relative to the keypad buttons 5, such that the sides of the respective slot shaped portions 104 engage within the recesses 109 formed on opposite sides of each keypad button 105. It will be appreciated that as the main body portion of each keypad button 105 is of larger diameter than the width of each slot shaped portion 104, the buttons 105 cannot be depressed and hence, in the position illustrated in Figures 7 and 9, cannot operate the contacts lying beneath them.

Figures 10 to 16 show a further embodiment of the invention which relies on the same locking mechanism for the keypad keys 205, as in the previous embodiment.

However, in the embodiment of Figures 10 to 16, the individual openings are interconnected to form a series of parallel elongate openings 203. More specifically, each opening 203 comprises a wide elongate slot portion 202 and three circular portions 204 interconnected by narrow slot portions 206. Also as in the previous embodiment, a pair of recesses 209 are provided on opposite sides of each keypad button 205. The recesses 209 have the effect of locally narrowing the keypad buttons 205, such that in the region of the recesses 209, the keypad buttons can be accommodated between the sides of the narrow slot portions 206 of the openings 203.

When the locking plate 201 is in the unlocked position, as shown in Figures 10 and 13, each keypad button 205 is located either within one of the wide slot portions 202 or within one of the circular openings 104, so that each keypad button 205 is provided with some play and can be depressed to operate the contact lying beneath it.

Figures 11 and 14 show the keypad in a fully locked position. In this mode, the opposite sides of respective narrow slot portions 206 are engaged within the recesses 209 formed in opposite sides of eachkeypad button 205. As the main body of each keypad button 205 is of larger diameter than the narrow slot portions 206, the keypad buttons 205 cannot be depressed and, therefore, cannot operate the electrical contacts beneath them.

Figures 12 and 15 show the keypad in a further mode in which the top row of keypad buttons 205 are located within the wide slot portions 202 and hence are free to be depressed and to operate the electrical contacts beneath and the other keypad buttons 205 are held in a locked position by engagement of the sides of the narrow slot portions 206 in the recesses 209 of the keypad buttons 205.

The switching between the three modes in this embodiment is achieved, as in the other embodiments, by sliding a lock switch 215, which may be fixed to or integrally moulded with the locking plate 201, along a slot 217 formed in the side of the keypad casing 219.

However, in this embodiment, as the notch locking mechanism has three groves 223,225,227 the lock switch 215 can be located into any one of three positions, which correspond to the three modes described above.

In the embodiments described above, the lock plate 1,101,201 is slid in a single direction by movement of an integrally formed lock switch 15,215. However, it is contemplated that alternative modes may be achieved by sliding the locking plate in not only a first direction, but also in a direction substantially perpendicular to the said first direction and by forming the openings in the lock plate in a cross shape or other suitable configuration. As before, the openings would have wide and narrow portions, to achieve the required locking and unlocking conditions, depending on the position of the keypad buttons within the openings. Indeed, the present invention contemplates any number and combination of locking and unlocking modes, in which various different combinations of keypad buttons 5,105,205 are sequentially locked and unlocked by movement of the locking plate 1,101,201.

Although the preferred embodiment has been described with the recess in the form of a through hole, any type of recess is contemplated, including, for example slots or blind bores. Furthermore, instead of the pins being formed on the locking member and the recesses being formed in the buttons, the invention could also be realised in the opposite manner, ie. wherein each button has a protruding part and the locking member has a plurality of recesses. The same is also true for the notch mechanism wherein the grooves and notch could be transposed Although the specific embodiments have been described in relation to a mobile phone, the invention could also be used with other types of portable apparatus, for example, a personal=organiser or calculator.

Claims (14)

1. A keypad comprising: a plurality of depressable keys; and a locking member movable from a disengaged position in which each key is free to move, to an engaged position in which depression of at least some of the keys is restrained, the locking member and at least some of the keys being provided with cooperating formations, which in an engaged position of the locking member are interconnected to restrain the movement of the keys.

2. A keypad as claimed in claim 1, in which the locking member is movable into a plurality of positions in which different combinations of keys are locked or unlocked.

3. A keypad as claimed in claim 2, in which the locking member is movable from a disengaged position in which all of the keys are free to move to a first engaged position in which the movement of the first combination of keys is restrained or to a second engaged position in which the movement of a second combination of keys, is restrained.

4. A keypad as claimed in any one of the preceding claims, in which the locking member comprises a plate having a plurality of openings, each opening being associated with and accommodating a ~ key or a respective group of keys.

5. A keypad as claimed in claim 4, in which the cooperating formations comprise: a plurality of projections, each projection being formed on an edge of an opening and projecting inwardly of the opening; and a plurality of recesses formed in the keys, the plate being movable from the disengaged position in which the projections are withdrawn from the respective recesses, to the engaged position in which the projections are located in the recesses.

6. A keypad as claimed in claims 4 or 5, wherein the plate moves between the engaged and disengaged positions in a plane substantially perpendicular to the direction in which the keys are depressed.

7. A keypad as claimed in claim 6, in which the plate moves between the engaged and disengaged positions on first and second tracks located on the keypad.

8. A keypad as claimed in any one of claims 4 to 7, in which each opening is substantially the same shape as the corresponding key whi-ch it accommodates, but is elongated in the direction in which the plate moves between the engaged and disengaged positions.

9. A keypad as claimed in any one of claims 4 to 8, wherein the plate has a switch for enabling the user to move the plate between the engaged and disengaged positions.

10. A keypad as claimed in any one of claims 4 to 9, wherein the plate has means by which it can be held in the engaged and/or disengaged positions.

11. A keypad as claimed in claim 10, wherein the holding means comprises a notch on the plate, which cooperates with one of a plurality of grooves provided on the keypad apparatus, for holding the plate in one of a plurality of predetermined positions.

12. A keypad as claimed in any one of claims 4 to 11, wherein the plate is located beneath a casing on the keypad apparatus.

13. A keypad substantially as described herewith, with reference to and as shown in the accompanying drawings.

14. A mobile phone having a keypad as claimed in any one of the preceding claim.