LOCK OPERATING MECHANISM

Abstract: An operating mechanism for a lock of the type comprising a rotatable operating member and a lock member comprises a primary drive gear (25) arranged to be rotated by rotation of the operating member, a driven gear (26) for connection to the lock member, and a transfer gear (35) for transmitting rotary motion from the drive gear to the driven gear. The transfer gear is mounted on a corner plate (27) which rotates with the drive gear (25) when an electromagnet (29) is energised to bring the transfer gear into mesh with the driven gear (26).

Description: Lock Operating Mechanism This invention relates to an operating mechanism for a lock such as a door lock. A typical lock comprises a lock member, such as a latch; an operating member such as a handle, which is operable to release the latch and an operating mechanism for connecting the operating member to the latch. The operating mechanism is enabled by the presentation of a suitable key to the lock. Without the key, the operating member cannot be operated to release the latch. In some locks, the key itself is the operating member. In many modern locks the conventional metal key has been replaced by a card having a magnetic strip bearing an access code. The lock is provided with a card reading device which is associated with the lock operating mechanism. Typically, the lock operating mechanism includes an electromechanical device which receives electrical signals from the card reader, and whether or not the operating mechanism is enabled depends on whether or not the electromechanical device is energised. This invention relates to a lock operating mechanism which may be enabled or disabled in response to an electrical signal, and is therefore particularly suitable for a lock whose key is in the form of a card bearing a magnetically encoded strip. EP-A-0094592 discloses an operating mechanism suitable.for a lock comprising an electronic, decoding device, a rotatable operating member and a lock member. The operating mechanism shown in figure 4 of this document includes a gear which rotates when the operating member is rotated and which in turn causes rotation of a first rotatable member. The first rotatable member comprises a plate having teeth around a part of its circumference which engage the gear. A second rotatable member in the form of a gear wheel rotates about the same axis as the first rotatable member. A third member rotatable about the same axis and in the form of a further plate carries a transfer gear. The transfer gear is mounted via a slide so that is is linearly movable with respect to the third rotatable member. An external stop having a camming surface limits movement of the slide and the slide is biased towards the stop. When the third rotatable member rotates, the slide travels along the camming surface of the stop against the biasing force to bring the transfer gear into engagement with the second rotatable member. An electromagnet is positioned between the first and third rotatable members to clamp them together when energised. Thus, when the electromagnet is energised following acceptance of an input electronic code the first and third rotatable members rotate together in response to rotation of the operating member which causes the transfer gear to engage the second rotatable member. When the electromagnet is not energised, rotation of the operating member simply rotates the first rotatable member alone. This arrangement requires a large number of components to transmit motion from the operating member to the. lock member-. The use of a separate camming . surface further complicates the arrangement. The present invention preferably provides an operating mechanism for a lock of the type comprising a rotatable operating member and a lock member; the mechanism comprising primary drive means arranged to be rotated by rotation of the operating member, final drive means for connection to the lock member and transfer means for transmitting rotary motion from the primary drive means to the final drive means, wherein the primary drive means is capable of limited motion with respect to the transfer means and switch means are provided for selecting whether said limited motion takes place before or after the interconnection of the primary drive, the final drive and the transfer means. Thus, with the switch in one state, the motion of the primary drive means occurs before interconnection and therefore after interconnection no further motion of the primary drive means with respect to the transfer means is possible, and therefore no transmission of motion can take place and the mechanism is locked. However, if interconnection takes place first, the limited motion of the primary drive means can be transmitted to the final drive means. Another aspect of the invention provides an operating mechanism for a lock comprising a rotatable operating member and a lock member; the operating mechanism comprising a first rotatable member arranged to rotate about a first axis in response to rotation of the operating member; a second rotatable member which rotates in use about a second axis to cause the release of the lock member; a transfer gear for transferring rotary motion to the second rotatable member; the transfer gear being rotatably mounted on a third rotatable member which is arranged to rotate about the first axis; the transfer gear being arranged to be driven by the first rotatable member and the third rotatable member being rotatable to drivingly connect the transfer gear and the second rotatable member. An electromagnet is preferably provided clamp together the first and third rotatable members when energised whereby rotation of the first rotatable member causes rotation of the third rotatable member. The operating mechanism of the present invention has a number of advantages over the known operating mechanism, described above. For example, no separate camming surface is required in order to bring the transfer gear into contact with the second rotatable member. The parts of the mechanism are simply arranged so that rotation of the member carrying the transfer gear connects the transfer gear with the second rotatable member. As a result, the first rotatable member, the transfer gear and the second rotatable member maybe directly interconnected. Preferably, the first rotatable member comprises a gear wheel which is connected to the operating member via a shaft such that rotation of the operating member causes rotation of the gear wheel. Furthermore, the second rotatable member preferably comprises a gear wheel and is preferably mounted for rotation with a spindle which is directly connected to the lock member such that rotation of the spindle causes release of the lock member. Clearly, with such an arrangement, ' the number of components required for ' transmitting motion from the operating member to the lock member is greatly reduced as .compared to the known operating mechanism. Furthermore it will be noted that such an arrangement utilises purely rotational motion. In the preferred embodiment of the invention, the first rotatable member carries teeth around a part of its periphery and also a stop member. The stop member is positioned such that after a certain angle of rotation of the first rotatable member with respect to the transfer gear it abuts the transfer gear and prevents further relative motion between the first rotatable member and the transfer gear. When the electromagnet is de-energised, rotation of the operating member from the normal position causes rotation of the first rotatable member and hence the transfer gear until the stop member engages the transfer gear. At this point, further rotation of the operating member will cause rotation of the third rotatable member, to which the transfer gear is fixed to bring the transfer gear into contact with the second rotatable member. However, the stop member prevents rotary motion being transferred from the first rotatable member to the second rotatable member via the transfer gear. The contact between the transfer gear and the second rotatable member prevents further rotation of the operating member. Energisation of the electromagnet prevents relative motion between the first and third rotatable members. Thus, starting from the normal position, rotation of the operating member with the electromagnet energised will cause the first and third rotatable members to rotate together without any movement of the transfer gear relative to them. The strength of the electromagnet is preferably such that it can be over- come with a little extra turning force on the operating member when the ' transfer gear engages the second rotatable member. At this point rotary movement can be transferred from the first to the second rotatable member via the transfer gear because the stop on the first rotatable.member has not yet engaged the transfer gear. The stop may be configured so as to ensure that the first rotatable member does not come out of mesh with the transfer gear. The lock operating mechanism of the present invention can be used to operate any lock whose latch is released by rotation of a spindle. This means that it can be used to adapt an existing lock for electronic operation without the need to make any alterations to the latch release mechanisms. It will be noted that all gear members are in the same plane which means that the operating mechanism can be made relatively thin. The advantage of this is that the operating mechanism can then be mounted on the exterior of a door without presenting a bulky, unsightly appearance, and more importantly it is a simple matter to adapt an existing lock using this invention because there are no parts passing through the door. An embodiment of the invention will now be de¬ scribed by way of example and with reference to the accompanying drawings in which: Figure 1 is a partial perspective view of the exterior of a door having a conventional door lock mechanism to which the operating mechanism of the present invention is connected; Figure 2 is a partial perspective view of .the interior of the door shown in Fig.1; . Figure ' 3 is an exploded perspective view of the lock operating mechanism shown in Figure 1 ; Figure 4 is an exploded view of certain parts of the operating mechanism; Figure 5 is a detailed view of the parts of the lock operating mechanism shown in their normal position; Figures 6 and 7 are views corresponding to Figure 6 showing the positions of the parts after rotation of the operating member with the electromagnet de-energised. Figures 8 and 9 are views corresponding to Figure 6 showing the positions of the parts after rotation of the door handle, the electromagnet having been energised. Referring firstly to Figs 1 and 2, the illustrated door lock arrangement includes an exterior door handle 10, an interior door handle 11, and a mortice lock having a latch 12. The interior door handle 11 is operable to rotate a spindle located within the door and the spindle is connected to the latch 12 such that rotation of the spindle causes retraction of the latch. The lock is provided with an operating mechanism according to the present invention which connects the exterior handle 10 to the spindle. The operating mechanism is provided with a card reading device 17 having a slot 18 for receiving a card. The slot is located above the exterior door handle 10. The- card reader 17.is arranged to supply electrical signals to the operating mechanism to enable the operating mechanism when a card bearing an acceptable code has been presented to the card reader 17. The door is also provided with a further bolt 1 commonly referred to as a "dead bolt" which is only operable from the interior of the door by means of a further handle 13. The parts of the lock arrangement located on the interior of the door, i.e. the handle 11 and the handle 13 for the dead bolt, as well as the bolts 12 and 14, are conventional and will not be further described. The remaining components of the lock, ie: the card reader 17 and the operating mechanism are preferably located on the exterior surface of the door, enclosed within a housing 20 which may be screwed or otherwise secured to the door. Batteries for the card reader may also be located in the housing. The housing 20, enclosing the card reader 17, lock operating mechanism and batteries for the card reader, together with the exterior door handle 10 may be manufactured as a unit to be connected to a conventional door lock. Thus a conventional door lock may be converted to a card-operated lock by removing the existing exterior handle and replacing it with a unit incorporating the operating mechanism of the present invention. Figure 3 shows the general layout of the housing 20 and the mechanical components of the operating mechanism. Alternatively, if the lock operating mechanism of the present invention is being installed as part of an entirely new lock it is more convenient for components of the lock to be located in a recess in the door surface or, particularly in the case of electronic components, pn the inside of the door. Thus, for example, • the- batteries and electronic components-of the card reader may be located inside the door with electrical connections passing through the door. The card reader 17 and ancillary electronic equipment may be conventional and will not be described further. Referring to Figures 3 to 9, the lock operating mechanism according to the present invention will now be described in more detail. The lock operating mechanism includes a first rotatable member comprising a driving gear 25 which is coupled to the exterior door handle 10, via a shaft 28, for rotation therewith. As shown in Figure 4 the shaft 28 and gear 25 are coupled by a pin 24. A second rotatable member comprises a driven gear 26 which is coupled to and rotates with a spindle 15. The spindle 15 is con¬ nected to the latch 12 in a conventional manner such that rotation of the spindle causes retraction of the latch. The axis of rotation 30 of the driven gear 26 is spaced from the axis of rotation 40 of the driving gear 25. ■ Each gear 25, 26 carries teeth around at least a part of its circumference. A third rotatable member or carrier 27 is mounted for rotation about the shaft 28. As shown in Figures 3 and 5 the carrier is formed from a single piece of sheet metal and forms a plate member on either side of the driving gear. A transfer gear 35 is rotatabl-y mounted on the carrier plate 27. The transfer gear has teeth around the whole of its circumference and is mounted such that its teeth mesh with the teeth of the driving gear 25. The carrier plate 27 also carries an electromagnet.29. The driving gear 25 is provided with a metal stop 31 which acts as the pole piece for the electromagnet. When the electromagnet is energised it attracts the stop 31 to fix the gear wheel 25 with respect to the carrier 27. A stop 32 which may be provided on the housing 20 limits the anti-clockwise rotation of the carrier plate as viewed in the drawings. The carrier plate is biassed in the anti-clockwise direction against the stop 32 by a spring 34 which has one end secured to a pin 38 on the housing. The driven gear 26 is biassed in the anticlockwise direction against a stop 36 by means of a spring 37 having one end attached to a pin 38a on the housing. A spring associated with the handle ensures that gear 25 returns to its normal position. The illustrated lock mechanism operates as follows: Figure 5 shows the normal positions of the components of the mechanism. When the electromagnet is de-energised, rotation of the exterior handle 10 in the clockwise direction as shown in the drawings will cause rotation of the gear wheel 25 independently of the carrier 27 and this will cause anti-clockwise rotation of the transfer gear 35. As soon as the stop 31 abuts against the transfer gear 35 no further relative movement in this direction between the gears 25 and 35 is possible. This position is shown in Figure 6. The driving gear 25, transfer gear 35 and carrier 27 are now all fixed with respect to each other and thus further clockwise rotation of the handle 10 will cause all three members to rotate about the axis 40, until the transfer gear abuts against the driven gear 26. At this point the driven gear stops further rotation of the carrier 27 and the' stop 31 is still preventing rotation of the transfer gear and thus the handle 10 cannot be rotated any further. This position is shown in Figure 7. When a card bearing an acceptable code is presented to the card reader 17 an electrical signal from the card reader energises the electromagnet, to fix the driving gear 25 with respect to the carrier 27. Turning of the handle 10 now causes the driving gear 25, the transfer gear 35 and the plate 27 to rotate together about the axis 40 without any rotation of the transfer gear relative to the driving gear. Thus, the ■ position shown in Figure 8 will be reached, in which the transfer gear has engaged the driven gear 26 but the stop 31 has not engaged the transfer gear. The strength of the electromagnet is chosen such that when this position is reached, a little extra turning force on the handle will be sufficient to break the contact between the electromagnet and the stop 31. At this point, the handle and therefore the driven gear 25 are being held by the operator preventing clockwise rotation of the transfer gear 35 and therefore the carrier plate does not spring back to its normal position. Further rotation of the handle in the clockwise direction causes rotation of the driving gear 25 independently of the carrier plate and thus rotation of the transfer gear which is passed on to the driven gear 26. The spindle 15 then rotates to cause retraction of the latch. This is shown in Figure 9. Thus, with the operating mechanism described above, a lock can only be unlocked when a card bearing an acceptable code is presented to the card reader ' . In the embodiment shown the driven gear can be rotated through about 50° "before the stop 31 contacts the transfer gear 35. This is sufficient turning of the spindle to open the majority of known spindle type locks. The electromagnet 29 is automatically de-energised after ten seconds to ensure that the lock is not accidentally left "unlocked" and to save power. Thus the user must open the door within ten seconds of presenting his card, otherwise he must present his card again. One or more lights may be provided to indicate the time during which the door can be opened. For example, a green light could indicate that the door can be opened and a red light could indicate that the card must be presented. The configuration and dimensioning of the components is preferably chosen such that at the position shown in Figure 7 in which the handle has been turned while the electromagnet is de-energised, the transfer gear 35 and the driven gear 26 meet with their teeth "crown to crown" and cannot mesh. This is not an essential feature because even if they do mesh, rotation of the driven gear 26 is prevented by the stop 31 which is preventing rotation of the transfer gear. The use of the stop 31 has the advantage of preventing the driving gear 25 and the transfer gear from moving out of mesh. It has been found that it is useful to provide means for limiting the movement of the carrier 27 in the clockwise direction as shown in the drawings. The reason for- this is that once the transfer gear 35 and the driven gear 26 are engaged any further movement of the carrier 27 tends to push them together and . interfere with the relative rotary motion between the transfer gear and the driven gear. Also, the "over engagement" which tends to push the gears together as they rotate, can cause excessive wearing of the gears. One possibly is to extend the shaft of the transfer gear 35 beyond the carrier member 27 and provide means on the housing for engagement with the protruding end or ends of the shaft. A stop may be moulded in the housing shown in Figure 3, for engagement with one end of the shaft and an arcuate groove may be provided in the opposing cover plate to guide the travel of the other end of the shaft. It will be appreciated that a number of alternative arrangements are possible to achieve the same effect, ie: once the transfer gear 3.5 has engaged the driven gear 26 further clockwise rotation of the carrier 27 is prevented. An extra microswitch, shown at 45 in the drawings, may be provided for indicating when the door is opened. In the illustrated embodiment the microswitch 45 is positioned on the stop 36 on the housing. The switch is opened when the two stops 33 and 36 are moved apart. The opening of switch 45 may be used as a signal to de-energise the electromagnet if it is not already de-energised to save power and prolong battery life. The card reader may have a RAM associated with it for storing information on the most recent users of the lock. The opening of the microswitch 45 may be used to signal loading of the card information into the RAM. Thus, for example in the case of a hotel r = oom, ' details of persons entering the room may be recorded. By using the " microswitch associated with the driven gear 26 it is ensured that details from invalid cards which do not result in an entry are not stored. Any suitable microswitch may be used. The switch 45 shown in the drawings comprises a leaf spring which contacts a terminal when the stops are in their normal positions. The particular embodiment of the invention shown in the drawings can easily be adapted for "right hand" or "left hand" operation by simply relocating the components to provide a "mirror image" arrangement. The housing shown in Figure 3 and Figures 5 to 10 is provided with the necessary locating members to enable the components to be mounted either way round. Thus, as is most clearly shown in Figure 3, there are two symmetrically located annular flanges 50 and 50a for receiving the driven gear 26, two symmetrically located stops 32 and 32a and pins 38 and 38a are symmetrically located so that each can have either spring 37 or 34 attached to it. Thus, to change the mechanism from "right hand" to "left hand", the driven gear is moved from flange 50 to flange 50a and the assembly comprising carrier 27, transfer gear 35, driving gear 28 and electromagnet 29 is simply turned over. In fact, the arrangement of Figure 3 is the opposite way round to that of Figures 5 to 9. As also clearly shown in Figure 3 the driven gear 26 has a square hole through it for receiving a square spindle. However, the mechanism can be used with a lock having any shape of spindle by simply providing a suitably shaped link member to connect it

Claims: CLAIMS : 1. An operating mechanism for a lock of the type comprising a rotatable operating member and a lock member; the mechanism comprising primary drive means arranged to be rotated by rotation of the operating member, final drive means for connection to the lock member and transfer means for transmitting rotary motion from the primary drive means to the final drive means, wherein the primary drive means is capable of limited motion with respect to the transfer means and switch means are provided for selecting whether said limited motion takes place before or after the interconnection of the primary drive, the final drive and the transfer means. 2. An operating mechanism as claimed in claim 1 in which the primary drive means comprises a first rotatable member arranged to rotate about a first axis, the final drive means comprises a second rotatable member which rotates in use about a second axis to cause the release of the lock member, and the transfer means comprises a transfer gear rotatably mounted on a third rotatable member which is rotatable about the first axis, the transfer gear being arranged to be driven by the first rotatable member and the third rotatable member being rotatable to drivingly connect the transfer gear and the second rotatable member. 3. An operating mechanism as claimed in claim 3 in which the switch means includes an electromagnet which clamps together the third rotatable member and the first rotatable member when energised whereby rotation of the first rotatable member causes rotation of the third rotatable member. 4. An operating mechanism as claimed in claim 3 in which the strength of the electromagnet is such that when the transfer gear is drivingly connected to the second rotatable member further turning of the operating member will overcome the electromagnet and enable rotation of the first rotatable membe-r - independently of the third rotatable member. 5. An operating mechanism as claimed in claim 2, 3 or 4 in which the first rotatable member comprises a toothed member and the transfer gear is mounted on said third rotatable member so as to mesh with the first rotatable member. 6. An operating mechanism as claimed in claim 5 in which the first rotatable member carries teeth around -only a part of its periphery and also a stop member for limiting rotation of the first rotatable member with respect to the transfer gear. 7. An operating mechanism as claimed in claim 6 in which the stop member is arranged to ensure that the transfer gear and the first rotatable member do not become disengaged. 8. An operating mechanism as claimed in any of claims 2 to 7 further comprising means for limiting the motion of the third rotatable member. 9. An operating mechanism as claimed in any of claims 2 to 8 in which the first and second rotatable member and the transfer gear all rotate in the same plane. 10. An operating mechanism as claimed in any preceding claim in which the primary drive means includes a drive gear which is directly connected to the operating member via a shaft such that rotation of the operating member causes rotation of the drive gear. 11. An operating mechanism as claimed in any preceding claim in which the final drive means comprises a second rotatable member which is mounted for rotation with a spindle which is directly connected to the lock member.

Inventors: MCGUIRE GEOFFREY, MCGUIRE, GEOFFREY
Applicants: UNIQEY HOLDINGS, UNIQEY HOLDINGS LIMITED
Application year: 1988
Main classification: E05B47
IPC codes: E05B47, E05B49