Keyboard switch matrix assembly with improved guide means for reducing transfer of bounding motion to movable conductor

Claim 2

A keyboard device comprising: a base; a plurality of key bodies mounted on the base for reciprocal motion, the key bodies having a generally rectangular cross section perpendicular to the direction of motion; at least two electrical contacts mounted on the base for each key body; a bridging electrical conductor movable into and out of engagement with each said at least two electrical contacts, said conductor movable into engagement with said contacts upon a predetermined amount of force transferred from said key body; guiding means for reducing the transfer of bounding motion to the conductor by preventing skewing motion of the key body, the guiding means includes a tab extending laterally from each corner of the rectangular cross section of the key body, said base including a groove for each tab, each tab slidably received in its respective groove.

Claim 3

A keyboard device comprising: a base; a plurality of key bodies mounted on the base for reciprocal motion; at least two electrical contacts mounted on the base for each key body; a bridging electrical conductor movable into and out of engagement with each said at least two electrical contacts, said conductor movable into engagement with said contacts upon a predetermined amount of force transferred from said key body; guiding means for reducing the transfer of bounding motion to the conductor by preventing skewing motion of the key body, the guiding means for each key includes a generally cylindrical element mounted in the base, said element having an axially extending bore, a plunger slidably received in said bore and movable toward and away from the electrical conductor, the plunger having a diameter which is approximately one-third of the length of the bore and the clearance between the plunger and the bore between 0.002 and 0.006 inches.

Claim 4

A keyboard device comprising: a base; a plurality of key bodies mounted on the base for reciprocal motion; at least two electrical contacts mounted on the base for each key body; a bridging electrical conductor movable into and out of engagement with each said at least two electrical contacts, said conductor movable into engagement with said contacts upon a predetermined amount of force transferred from said key body; guiding means for reducing the transfer of bounding motion to the conductor by preventing skewing motion of the key body, the guiding means for each key includes a generally cylindrical element mounted in the base, said element having an axially extending bore, a plunger slidably received in said bore and movable toward and away from the electrical conductor, the plunger having a diameter which is approximately one-third of the length of the bore and the clearance between the plunger and the bore between 0.002 and 0.006 inches.

Claim 5

A keyboard device according to claim 2 in which the means for reducing bounding includes a spring member placed intermediate the plunger and the conductor.

Claim 6

A keyboard device according to claim 3 in which the conductor is a diaphragm having a negative sloped portion in its force displacement curve thereby producing tactile feedback.

Claim 7

A keyboard device according to claim 4 in which the diaphragm requires an actuating force in ranges of approximately 1 1/2 ounces to 8 ounces.

Claim 8

A keyboard device according to claim 5 in which the spring rate of the said spring member is less than approximately 5 pounds per inch.

Claim 9

A keyboard device according to claim 3 in which a bore having a closed end is provided in the plunger and the spring member is located in the bore and extends beyond the key body when there is no force appLied to the spring member.

Claim 10

A keyboard device according to claim 7 in which the spring member is a helical spring thereby providing movement differential.

Claim 11

A keyboard device according to claim 7 in which the spring member is a solid elastomeric element thereby enhancing tactile feedback.

Claim 12

A keyboard device according to claim 3 in which the conductor is a diaphragm having a generally positive sloped force displacement curve throughout the displacement used in the keyboard device thereby producing noiseless operation of the diaphragm.

Claim 13

A keyboard device according to claim 2 in which means are provided to maintain the electrical conductor away from the contacts when the key body is in the unactuated position.

Claim 14

A keyboard device according to claim 2 in which the clearance between the plunger and the bore is nominally 0.004 inches.

Claim 15

A keyboard device comprising: a base of generally rectangular configuration in plan view, the base having a plurality of apertures formed therein, an annular hub portion mounted in the base about each aperture to provide an extended guideway; a plurality of key bodies, one for each aperture, each body having an extended cylindrical portion closely and slidingly fitted in a respective aperture, first spring seating means formed in the distal end of the cylindrical portion; a circuit board located beneath the body and provided with at least two peripherally located contacts and one centrally located contact for each key body and located in alignment therewith; electrical conductor retaining means located intermediate the circuit board and the body, the retaining means including a pocket and second spring seating means for each set of two output and one power supply contacts; an electrical conductor overlying each set of two output contacts and one power supply contact and adapted to move into and out of bridging engagement with the three contacts; a first spring member seated in the first spring seating means and applying a first bias to the electrical conductor in a direction tending to cause bridging engagement of the three contacts; a second spring member underlying each electrical conductor and seated in the second spring seating means and applying a bias to the electrical conductor in a direction tending to prevent bridging engagement of the three contacts, the bias of the second spring means lifting the electrical conductor away from the circuit board when the key is unactuated, upon actuation of the key the conductor moving into bridging engagement of the two output contacts prior to engagement with the centrally located power supply contact thereby preventing undesirable back circuits.

Claim 16

A keyboard device comprising: a base of generally rectangular configuration in plan view, the base having a plurality of apertures formed therein, an annular hub portion mounted in the base about each aperture to provide an extended guideway; a plurality of key bodies, one for each aperture, each body having an extended cylindrical portion closely and slidingly fitted in a respective aperture, first spring seating means formed in the distal end of the cylindrical portion; a circuit board located beneath the body and provided with at least two peripherally located contacts and one centrally located contact for each key body and located in alignment therewith; electrical conductor retaining means located intermediate the circuit board and the body, the retaining means including a pocket and second spring seating means for each set of two output and one power supply contacts; an electrical conductor overlying each set of two output contacts and one power supply contact and adapted to move into and out of bridging engagement with the three contacts; a first spring member seated in the first spring seating means and applying a first bias to the electrical conductor in a direction tending to cause bridging engagement of the three contacts; a second spring member underlying each electrical conductor and seated in the second spring seating means and applying a bias to the electrical conductor in a direction tending to prevent bridging engagement of the three contacts, the bias of the second spring means lifting the electrical conductor away from the circuit board when the key is unactuated, upon actuation of the key the conductor moving into bridging engagement of the two output contacts prior to engagement with the centrally located power supply contact thereby preventing undesirable back circuits.

Claim 17

A keyboard device according to claim 13 in which the second spring means is a generally eliptically shaped wave member having a centrally located aperture larger than and circumscribing the centrally located contact and two tab portions generally located on the major axis of the member and the tab portions extending into the second spring seating means.

Claim 18

A keyboard device according to claim 13 in which the electrical conductor is a diaphragm.

Claim 19

A keyboard system comprising: a circuit board having a plurality of sets of contacts mounted thereon, each set including at least two output contacts and one signal contact; an electrical conductor mounted over each set of contacts and adapted to move into and out of engagement with the contacts of the set; a generally eliptically shaped wave spring member provided for each set of contacts having a centrally located aperture larger than and circumscribing at least one of the contacts of a set and two tab portions generally located on the major axis of the member, spring seating means for each spring member, the tab portions extending into the spring seating means thereby maintaining the conductor out of engagement with its set of contacts in the unactuated state; and keyboard actuation means to cause the electricAl conductor to move toward its set of contacts against the bias of the said wave spring member.

Claim 20

A keyboard system comprising: a circuit board having a plurality of sets of contacts mounted thereon, each set including at least two output contacts and one signal contact; an electrical conductor mounted over each set of contacts and adapted to move into and out of engagement with the contacts of the set; a generally eliptically shaped wave spring member provided for each set of contacts having a centrally located aperture larger than and circumscribing at least one of the contacts of a set and two tab portions generally located on the major axis of the member, spring seating means for each spring member, the tab portions extending into the spring seating means thereby maintaining the conductor out of engagement with its set of contacts in the unactuated state; and keyboard actuation means to cause the electricAl conductor to move toward its set of contacts against the bias of the said wave spring member.

Claim 21

A keyboard system according to claim 16 in which the electrical conductor is a diaphragm, the output contacts are mounted in alignment with the outer peripheral portion of the diaphragm, the signal contact is mounted in alignment with the center portion of the diaphragm, the wave spring member circumscribing the signal contact, whereby actuation movement of the diaphragm toward its set of contacts will result in engagement of the diaphragm with the output contacts prior to engagement of the diaphragm with the signal contact.

Claim 22

Calculator apparatus comprising: a housing, the housing having a key array panel and a read out panel; a circuit board mounted in the housing having calculator circuitry and a plurality of sets of contacts mounted thereon, each set including at least one output and one signal contact; a movable electrical conductor mounted over each set of contacts and adapted to move into and out of engagement with its set of contacts; a plurality of key bodies, one for each conductor mounted on the circuit board each key body in alignment with a respective conductor; and means for reducing the transfer of bounding motion to the conductor including guiding means for each key body including a generally cylindrical element mounted in the housing, said element having an axially extending bore, a plunger slidably received in said bore and movable toward and away from the electrical conductor, the plunger having a diameter which is approximately one-third of the length of the bore and the clearance between the plunger and the bore between approximately 0.002 and 0.006 inches.

Claim 23

Calculator apparatus comprising: a housing, the housing having a key array panel and a read out panel; a circuit board mounted in the housing having calculator circuitry and a plurality of sets of contacts mounted thereon, each set including at least one output and one signal contact; a movable electrical conductor mounted over each set of contacts and adapted to move into and out of engagement with its set of contacts; a plurality of key bodies, one for each conductor mounted on the circuit board each key body in alignment with a respective conductor; and means for reducing the transfer of bounding motion to the conductor including guiding means for each key body including a generally cylindrical element mounted in the housing, said element having an axially extending bore, a plunger slidably received in said bore and movable toward and away from the electrical conductor, the plunger having a diameter which is approximately one-third of the length of the bore and the clearance between the plunger and the bore between approximately 0.002 and 0.006 inches.