Key operated switch

[57] ABSTRACT

A key operated switch is provided having a locking portion operative in response to insertion of a key to unlock and rotate. A nonconductive actuation cylinder is coupled to and rotates with the lock. This actuation cylinder has a conductive contact bar mounted therein, and has a key slot through the center. Circuit means are provided for connecting the actuation cylinder contact bar and external circuitry when the actuation cylinder is rotated. The key is provided having a first portion for insertion into the lock means for unlocking and rotating the same, and a second portion for insertion through the actuation cylinder key slot. The second portion is operative to inhibit portions of the circuit means from engaging the actuation cylinder contact bar.

Claims, 4 Drawing Figures

<img file="US3663774A_D0001.tif" />

Patented May 16, 1972

3,663,774

<img file="US3663774A_D0002.tif" />

Sheets-Sheet 1

<img file="US3663774A_D0003.tif" />

<img file="US3663774A_D0004.tif" />

<img file="US3663774A_D0005.tif" />

<img file="US3663774A_D0006.tif" />

inventor:

ALVIN FEDER

BY:

ATTY.

Patented May 16, 1972

3,663,774

Sheets-Sheet 2

<img file="US3663774A_D0007.tif" />

inventor: ALVIN FEDER by:

ATTY.

3,663,774

FIG. 3 is a section view of the actuation cylinder shown in

FIG. 2, along the section lines indicated as AA;

FIG. 4 is a plan view of a key used in the key operated switch.

KEY OPERATED SWITCH

BACKGROUND

Certain types of communication systems, for example police vehicular status systems, and certain types of credit card recording systems, such as credit card sales of gasoline, require a remote unit to transmit the identification number of the user to a central location. The signal transmitted is usually a binary coded form of the decimal digit identification number. The remote unit must therefore be capable of accepting a device which has the user’s number stored therein, and which programs the unit to send a signal representing the binary coded form of the decimal digit to a central location. One system previously employed used credit cards and credit card readers. The credit cards are easily bent out of shape and destroyed.

Another system uses a plug-in type printed circuit module and the associated circuitry for sending a signal representing the binary coded decimal digit. The plug-in module is cumbersome to carry and easily damaged. A third system employs a key and a switch, activated by insertion of the key. Such systems can easily be operated by an improper key.

SUMMARY

It is an object of this invention to provide a key operated switch.

Another object of this invention is to provide a key operated switch which cannot be activated until unlocked by the correct key.

Yet another object of this invention is to provide a key operated switch wherein each use wipes the switch contacts.

Still another object of this invention is to provide a key operated switch which must be unlocked and rotated in a predetermined arc before the switch contacts are activated.

In practicing this invention a key operated switch is provided which has a locking portion operative in response to insertion of a key to unlock and rotate. A nonconductive actuation cylinder is coupled to and rotates with the lock. The actuation cylinder has a conductive contact bar mounted therein 40 and a key slot through the center. Guide channels are cut in the cylindrical surface perpendicular to the axis of the cylinder. Circuit boards are provided having resilient conductive springs mounted thereon. The springs are positioned in the guide channels of the actuation cylinder and contact the 45 actuation cylinder contact bar when the cylinder is rotated. One of the springs can have an operating potential coupled thereto from the external circuitry. This potential is coupled through the contact bar to the other conductive springs and then to the external circuitry.

A key is provided which has a first portion for insertion into the locking device for unlocking and rotating the same. A second portion of the key is inserted through the actuation cylinder key slot. This second portion has an edge which extends into the guide channels. The edge has notches cut 55 therein which align with certain of the guide channels when the key is properly inserted. The notches are cut in accordance with the desired binary coded decimal digit or number to be transmitted. If a notch is cut in the key to correspond to a particular guide channel, the resilient springs will go be allowed to contact the actuation cylinder contact bar allowing a potential to be coupled through the spring to the external circuitry. If there is no notch cut in the key edge, the resilient conductive spring will be lifted by the key edge extending into that guide channel, and contact with the actuation cylinder contact bar will be inhibited. The absence of a potential coupled to the external circuitry by the spring represents a binary one. The presence of a potential represents a binary zero.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the key operated switch with the key inserted and shown in the two positions;

FIG. 2 is an exploded perspective view of the key operated switch of FIG. 1;

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, the key operated switch is shown with key 10 inserted into key slot 11 of actuation cylinder 12. The dotted lines show key 10 in its alternate, unlocked, position. FIG. 1 shows the parts of the switch described below in assembled relation.

Referring to FIG. 2, the exploded perspective view of the switch allows all of the component parts to be seen. Lock 15 includes a first portion 16, known as a lock housing, and a second portion 17, positioned within the first portion, known as a lock cylinder. A locking mechanism, located within lock cylinder 17, locks cylinder 17 and housing 16 together. Housing 16 and cylinder 17 are unlocked and allowed to rotate with respect to one another by inserting the correct key, such as key 10, into slot 18 of lock cylinder 17. In the embodiment shown, lock housing 16 and lock cylinder 17 can rotate 90° with respect to one another. Lock housing 16 has a flat portion 19 which, when the switch is assembled, acts as a key to prevent lock housing 16 from rotating along with lock cylinder 17. A shoulder 21 on lock housing 16 prevents lock 15 from being pulled backward out of its housing when assembled. A washer 20, secured to the rear surface of lock cylinder 17, rotates with lock cylinder 17. Washer 20 prevents lock 15 from being pulled forward out of its mounting, just as shoulder 21 of lock housing 16 prevents lock 15 from being pulled backward out of its housing.

A nonconductive actuation cylinder 12, is positioned against lock 15. When in assembled relation, end 25 of cylinder 12 has a depression 24 which accepts the raised end 26 of lock cylinder 17 on lock 15. Actuation cylinder 12 has a key slot 11 which extends through the center, along the axis With a key, such as key 10 shown in FIG. 4, inserted through cylinder 12 into lock 15, lock cylinder 17 of lock 15 will unlock allowing lock cylinder 17 and cylinder 12 to rotate together in a 90° arc.

Actuation cylinder 12 has guide channels 27 cut into the cylindrical surface. Referring to FIG. 3 there is shown a section view of cylinder 12 taken along the section lines AA in FIG. 2. Conductive contact bars 28 are embedded into cylinder 12, and positioned parallel with the axis of cylinder 12. Conductive contact bars 28 have a surface 29 which extends into guide channels 27. Key slot 11 of actuation cylinder ^al^so extends into the guide channels adjacent contact bars Zo.

Circuit means 32 are provided for connecting the switch to the externally operated circuitry. Circuit means 32 includes a printed circuit board 33 having printed circuitry 34 thereon. Terminals 35 secured to printed circuitry 34 are used for connecting the switch with the desired externally operated circuitry. Resilient conductive springs 36 are mounted on printed circuit boards 33, and coupled to printed circuitry 34. When circuit means 32 are assembled into the switch, resilient conductive springs 36 are positioned in guide channels 27 of actuation cylinder 12. Guide channels 27 maintain springs 36 in their proper position, preventing the springs from touching or interferring with one another.

A housing for holding lock 15, actuation cylinder 12 and circuit means 32 in assembled relation consists of first and second housing sections 40 and 41. Sections 40 and 41 are made identical to one another in order to reduce construction costs and ease the manufacturing process. The sections are positioned upside down with respect to one another and attached to one another by screws 42. Circuit means 32 each have a portion sandwiched between sections 40 and 41 with screws 42 passing through openings 37 to hold the rearward portions of circuit means 32 in assembled relation. Flat portion 19 of lock cylinder 16 keys with flat portion 52 of housings 40 and 41 to prevent rotation. Shoulder 21 seats in recess

AMI

3,663,774 of housing portions 40 and 41 to prevent lock 15 from being pulled out of the housing.

Front retainer plate 45 is secured to the ends of housing sections 40 and 41 by screws 46. Slots 47 in plate 45 accept tabs 48 of printed circuit board 33, retaining the front end of printed circuit boards 33, and therefore circuit means 32, in proper alignment. Opening 49 in plate 45 allows the raised portion at end 51 of actuation cylinder 12 to extend therethrough, and retains the remaining portion of actuation cylinder 12 in assembled relation between housing sections 40 and 41, and against lock 15.

Key 10, shown in FIG. 4, includes a first and second section, 55 and 56 respectively, shown separated by dashed lines. The first section inserts into and unlocks lock 15. The second section inserts into actuation cylinder 12. Edges 57 of key 10 extend into guide channels 27 of actuation cylinder 12. Notches 58 are cut into edges 57 of second section 56 in accordance with the desired binary coded decimal digit which is to be transmitted to the externally operated circuitry.

In operation, section 55 of key 10 is inserted through actuation cylinder 12 into lock 15, unlocking the lock housing 16 and lock cylinder 17. The key is rotated 90° as shown in FIG. 1 to its fully unlocked position. As key 10 is rotated, edges 57 of second section 56 on key 10, bear against resilient conductive springs 36 on circuit means 32, prohibiting contact with surface 29 of conductive contact bar 28 in cylinder 12. Where notches 58 have been cut into second section 56 of key 10, the resilient spring contacts 36 which align with these notches will be allowed to contact conductive contact bar 28. A main contact 38 provides a ground or other reference potential which is ' conducted through contact bar 28 to the contacted springs 36. This potential is coupled through printed circuitry 34 to terminals 35 of circuit means 32. From terminals 35 the potential is coupled to the externally controlled circuitry where it may , be used to represent a binary zero. The resilient conductive springs 36 which are not in contact with conductive contact bar 28 will represent the other binary value.

Requiring full rotation of cylinder 12 before actuation of Γ springs 36 to be wiped or slid across top surface 29 of conductive contact bar 28 with each usage. This prevents oxidation of the conductive springs and contact bar which could cause the switch to malfunction. The full rotation of the lock and cylinder before actuation of the external circuitry prevents accidental operation of the switch by insertion of a wrongly coded key.

As can be seen, a key operated switch has been provided which cannot be activated until unlocked by the correct key. Activation of the circuitry will not occur until the rotating portion of the lock and the actuation cylinder have been rotated in the full predetermined arc. Rotation in the full predetermined arc causes the switch contacts to be wiped by the contact bar thus preventing oxidation which could lead to improper operation.