Electrical Transmission Path for Electrical and Electro-Mechanical Locks

This application incorporates by reference applications Ser. No. 08/561,673, now abandoned, entitled ELECTRICAL ISOLATION OF KEY CYLINDER FOR ELECTRONIC LOCKS, and Ser. No. 08/567,824, abandoned entitled NON-CONDUCTING ACTUATOR TOP FOR AN ELECTRONIC LOCK. The referenced applications are assigned to the same assignee as the present application.

This invention relates generally to electrical and electro-mechanical locks and more particularly to an apparatus for providing an electrically conductive path, free of short circuits, between electrical and electronic components of such locks.

Locksets operated by both a traditional mechanical key and an electronic touch button are becoming more commonly available in the door hardware industry. In order to have the desired capability for dual operating modes, such locksets require the touch button target, against which the touch button key is applied, to be insulated from the chassis of the lock. This saves battery energy and protects electronic control signals by eliminating short circuits between the key cylinder and the chassis. A device for insulating a key cylinder from the associated lever, spindle, and chassis has been disclosed in two abandoned patent applications Ser. No. 08/561,673, entitled "ELECTRICAL ISOLATION OF KEY CYLINDER FOR ELECTRONIC LOCKS", and Ser. No. 08/567,824, NON-CONDUCTING ACTUATOR TOP FOR AN ELECTRONIC LOCK, which are commonly assigned, herewith, and are incorporated herein, by reference. The present invention addresses a preferred method of providing an electrically conductive path, around and through the electrically isolated key cylinder and latch actuator top, between an electronic touch button target and an electrical lock operating system in a lock operable by mechanical and electro-mechanical means. Transmittal of electronic impulses from the insulated touch pad target to the electrical lock control is required for full operation of the lock. Without such provision, the electrical mode of the lock operation will not function at all.

Locks are usually constructed mostly from metal, especially the mechanical operating components, and have numerous electrically conductive paths between those components during operation. Operation in the electronic mode requires that the electrical signal between the touch button key and the touch button target not be attenuated or altered by drainage of charges nor by importation of stray signals from contact with conductive surfaces in the lock chassis. This can be accomplished by making the lock parts from insulating polymers, ceramics, or other non-conductive materials. However such construction can result in locks having high cost together with inadequate strength, durability, and reliability. For example, compared to metals, polymers may be softer and weaker, while ceramics may be hard and brittle. Both materials are usually less durable than metals while often more costly. Of course, strength limitations can be compensated for by making parts thicker and larger, but very quickly, this approach results in oversize locksets which are unattractive and which do not fit in standard door preparations.

Another approach to electrical isolation is physical separation of the mechanical and electronic key provisions to prevent short circuits, but this is not favored because it increases the complexity and cost of the lockset, by requiring duplication of many functions, and detracts from operating convenience by requiring separated key application points.

Regardless of which approach is taken for insulating the electronic touch button and its associated circuitry from the rest of the lock, provision must always be made for transmittal of electronic impulses from the touch button to the electrical lock operating control system.

The foregoing illustrates limitations known to exist in present mechanical/electromechanical locksets. Thus, it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.

In one aspect of the present invention, an apparatus is disclosed for providing an electrical transmission path in a door lock to an electrical lock operating system from an electrical contact pin protruding axially from a pin tower of an insulated key cylinder having an electronic touch button for a front face, the door lock having an outside spindle operably engaged with a door handle containing the insulated key cylinder, including an insulated contact ring surrounding the spindle and having an electrically conductive pad on a portion of its outwardly facing surface which contacts the electrical contact pin when the door handle is in its parked position and a cable connected to the conductive pad and extending through the non-moving part of the door lock to the controlling electronics of the lock.

The foregoing and other aspects of the invention will become apparent from the following detailed description, when considered in conjunction with the accompanying drawings.

FIG. 1 is a schematic exploded perspective view illustrating one embodiment of the invention in a door lever handle and a portion of a door lock with the outer spindle omitted;

FIG. 2 is a schematic view of the conductor cable showing the excess voltage spark gap feature; and

FIG. 3 is an exploded perspective schematic view of an alternative embodiment of the invention.

FIG. 1 shows a door lever handle 10, which has a key cylinder 15 with a pin tower 18 and a contact pin 19 mounted within. The front face 17 of the key cylinder 15 is the touch target electronic key contact and also has a slot for the mechanical key. The key cylinder 15, tower 18, and face 17 are insulated from the handle 10 as disclosed in commonly assigned application Ser. No. 08/561,873, abandoned.

The lockset 20 has a chassis 25 with a hub 23 protruding therefrom, in which is journalled an outside spindle (omitted for clarity). An insulating ring 21 surrounds the outside spindle and is keyed to the hub 23 to prevent rotation of the ring. A conductive pad 22 covers an approximately 20.degree. arc on the outside face of the insulating ring 21 to provide an electrical contact with the contact pin 19 only when the handle 10 is at rest or in the parked position. A two-conductor cable 24 has one conductor connected to the hub 23, or other suitable ground, and the other to the conductive pad 22 of the insulating ring 21 and extends through an inactive portion of the lockset 20 to the controlling electronics. A spark gap is formed, as seen in FIG. 2, between the conductors of cable 24 by asperities 24a and 24b on neighboring portions of the conductors to provide a harmless short circuit to ground in case of an excessive voltage being applied to the cable. This provides added protection for the electronic control circuits.

In operation, beginning at the spring loaded contact pin 19, contact is made at conductive pad 22 of the insulating ring 21 and through the ring to the cable 24. The cable runs through the non-critical area of the lockset 20 and out the other side to the controlling electronics. Along the wire path, the conductors have asperities 24a and 24b which are in close proximity to each other to create a narrow spark gap which dissipates overcharging of the data connection.

This embodiment has several advantages, namely, that false and unwanted signals are avoided by the limited area of conductivity provided on the insulating ring which limits signalling to an "at rest" handle position; that cable runs are easy because they are through a non-critical outer portion of the lock; that the ground connection with the second conductor is easily made; and that the spark gap is easily provided with the two conductor cable.

FIG. 3 shows a second embodiment of the electrical transmission path of the present invention. The insulated key cylinder 15 has an un-insulated back face 16 and tailpiece blade 30. Tailpiece blade 30 drives a latch actuator cam (not shown) in response to operation of the key cylinder 15. A hollow insulating sleeve 35, having a rectangular cross-section and a circular front face, fits snugly over the tailpiece blade 30 to insulate the blade and the back face 16 of the key cylinder 15 from the latch actuator cam (not shown). A clip 37 within the sleeve 35 makes electrical contact with the tailpiece blade 30 and a wire 40 extends from the clip 37 through the inactive portion of the lock to the controlling electronics of the lockset. In this case, connection to the key cylinder 15 is made through the tailpiece 30 by the clip 37 within the insulating sleeve 35, and the insulated conductor wire 40 extends through the center of the lockset 20 and exits in a non-functional area to reach the controlling electronics inside the door. In this embodiment, the benefits include the low cost of the components needed to provide a data path from the key cylinder and the improved reliability of a direct electrical connection not involving a spring loaded contact pin. Clearly, the same insulating action can be achieved using either an insulation-coated latch actuating cam or a latch actuating cam made from a non-conductive material (not shown). The clip 37 is used in all cases to provide the desired electrical path.