Input device lock

• US 5,642,805 A
• Filed: 10/12/1995
• Issued: 07/01/1997
• Est. Priority Date: 10/12/1995
• Status: Expired due to Fees

• Current Assignee: Brian Tefft
• Original Assignee: Brian Tefft
• Inventors: Tefft, Brian
• Primary Examiner(s): Walczak, David J.
• Application Number:
  US08/542,391
• Time in Patent Office: 628 Days
• Field of Search: 200/43.04, 200/43.05, 200/43.01, 200/43.08, 200/43.11
• US Class Current: 200/43.08
• CPC Class Codes: H01H 2027/066 having anti-tamper provisions, e.g. avoiding the removal of the lock cylinder
• CPC Class Codes: H01H 27/08 wherein the key cannot be removed until the switch is returned to its original position H01H27/063 takes precedence

Abstract

An input device lock and method for preventing unauthorized access to the computer. The device is a lock switch that selectively enables or disables the line that effectuating data flow between the input device and the computer. Any input device may be selectively disabled using the present invention including a keyboard, mouse, track ball, joy stick, light pen, or other hand-held controller for example. Depending on the computer'"'"'s configuration, the data flow-effectuating line is known as the data line, input/output line, signal line, or clock line. When the flow-effectuating line is disabled by this device, no data is transmitted from the input device to the computer and therefore access to the computer is controlled. No other wires inside the cable are affected; in particular, the power and ground lines are not broken. The lock switch is the style that allows the key to be inserted or removed only when the lock switch is in the input device disabled state.

Claims

1. A device to prevent unauthorized use of a computer comprising:

a switch connected to a line effectuating data flow from an input device, the switch movable to and from a first condition wherein data may be transmitted from the input device to the computer,

and a second condition wherein the data is prevented from being transmitted from the input device to the computer,

wherein the operation of the computer remains unaffected when the switch is moved to the second condition.

2. The device according to claim 1 wherein the switch is enabled by a key, the key being detachably insertable into the switch for controlling the selection of the first condition and the second condition.

3. The device according to claim 2 wherein the key is insertable into the switch only when the switch is in the second condition.

4. An input device lock comprising:

a) a lock switch connected in series to a line that effectuates data flow between an input device and a computer; and

b) a key received by the lock switch, wherein the lock switch is enabled only when the key is received by the lock switch, a computer receives data transmitted from an input device only when the key is received by and enables the lock switch, and the operation of the computer remains unaffected when the lock switch is disabled.

5. A computer security device for selectively interrupting data transmitted from an input device to a computer along a cable having a first and second end, a power line and a line effectuating data transmission from the input device to the computer comprising:

a) an enclosure affixed to and surrounding a portion of the cable between the first and second ends;

b) a lock switch electrically connected to the line effectuating data transmission in the keyboard cable;

the lock switch having a first state that disables the lie and a second state that enables the line; and

c) a key insertable into and removable from the lock switch only if the lock switch is in the first state, the key allowing the lock switch to be switched between the first and second states when inserted into the lock switch;

whereby data transmitted from the input device is interrupted when the lock switch is in the first state but is unaffected when the lock switch is in the second state, and the computer acknowledges that the input device is properly connected while the lock switch is in either state since the power line is uninterrupted.

6. A computer security device according to claim 5 wherein the line effectuating data transmission is a clock line.

7. A computer keyboard lock for switching a line effectuating data transmission of a computer keyboard cable comprising:

a) a lock switch connected to the line effectuating data transmission of the keyboard cable, the lock switch having a key receiving portion enabling switching between an on position and an off position;

b) a key received by and switching the lock switch between the on position and the off position, the key insertable into and removable from the key receiving portion only when in the off position; and

c) a rigid enclosure surrounding a portion of the keyboard cable where the lock switch connects to the line carrying the data, the lock switch mounted to the enclosure such that the lock switch connection to the line effectuating data transmission is inside the enclosure and the key receiving portion is outside the enclosure;

whereby a computer keyboard is unable to send or receive data but is still acknowledged by a computer as being connected when the key receiving portion is in the off position, no lines in the keyboard cable other than the line effectuating data transmission are affected, and the computer keyboard functions normally when the key is inserted into the key receiving portion and is switched to the on position.

8. The device according to claim 7 wherein the rigid enclosure is mounted to the computer.

9. The device according to claim 7 wherein the line effectuating data transmission is a serial line of a computer input device.

10. A method for controlling access to a computer, the steps comprising:

a) connecting a lock switch to a cable having a power line and a line effectuating data transmission, the cable coupling an input device to a computer, the lock switch being electrically connected to the line effectuating data transmission, the lock having an on position wherein data can be transmitted and an off position wherein data transmission is inhibited;

b) inserting a key into the lock switch;

c) switching the lock switch to the on position such that the computer keyboard functions normally and the key cannot be removed from the lock switch

d) switching the lock switch to the off position; and

e) removing the key from the lock switch in only the off position;

whereby the computer receives data from the keyboard only when the key is in the lock switch and the lock switch is in the on position, and the key can be inserted into and removed from the lock switch only when the lock switch is in the off position.

11. The method according to claim 10 further comprising the step of controlling access to the keys from a central location.

12. A method for temporarily preventing unauthorized access to a computer through a keyboard coupled thereto by a cable having a power line and a line effectuating data transmission, comprising the steps of

a) inserting a key into a lock switch wherein the lock switch is connected to the line effectuating data transmission of the keyboard cable such that data transmission through the line effectuating data transmission is inhibited when the lock switch is in the off position;

b) switching the lock switch to an on position such that the keyboard functions normally and the key cannot be removed from the lock switch;

c) switching the lock switch to the off position; and

d) removing the key from the lock switch in only the off position;

whereby the keyboard transmits data only when the key is in the lock switch and the lock switch is in the on position, and the key is insertable into and removable from the lock switch only when the lock switch is in the off position.