Drum series printer with stop pawl engaged by a snap-over spring

Claim 2

In a data printer having a printing impression means, a type member having teeth thereon, a plurality of type characters carried by said member, cyclically operable means for yieldably advancing said member from an initial position to carry said type characters sequentially past said impression means, a stop pawl device having a part engageable with said teeth to arrest said member, means for guiding said pawl device from a retracted position to an arresting position for arresting said type member in different positions to present different ones of said type characters to said impression means, and means for moving said pawl device from said retracted position to said arresting position the combination with said pawl device of a snap-over spring engageable with said pawl device, means supporting said spring to yieldably maintain said pawl device either in said retracted position or in said arresting position, and means operable by said cyclically operable means for returning said pawl device to said retracted position and for maintaining said pawl device in said retracted position independently of said spring when said cyclically operable means is in said full cycle position.

Claim 3

The combination according to claim 1 comprising means for pivotally supporting said pawl device for movement between said arresting position and said retracted position, the angle between said retracted position and an intermediate position representing the cross-over point of said snap-over spring being less that the angle between said arresting position and said intermediate position whereby said snap-over spring effects a greater detenting force against said pawl in said arresting position than in said retracted position.

Claim 4

The combination according tO claim 1 comprising means for pivotally supporting said type member for movement about a first axis, means for pivotally supporting said pawl device for movement about a second axis, the engaging surfaces of each of said teeth and said device upon engagement extending perpendicular to a line passing between said axes whereby said surfaces will tend to drive said pawl device toward said member upon engagement of said surfaces.

Claim 5

The combination according to claim 1 comprising means operable by said cyclically operable means for returning said member to said initial position, said teeth being effective during return of said type member from a position in which said member is arrested by said pawl device to move said pawl device from said arresting position to said retracted position.

Claim 6

The combination according to claim 1 comprising means operable by said cyclically operable means for returning said member to said initial position, and means comprising said member when in said initial position for holding said pawl device in said retracted position.

Claim 7

The combination according to claim 5 wherein said last mentioned means comprises an abutment on said member engageable with said pawl.

Claim 8

In a data printer having printing impression means, a plurality of type members arranged side-by-side, a plurality of type characters carried by said members, means for yieldably advancing said type members to carry said type characters past said impression means, stop pawls engageable with said type members whereby to arrest said members, and means for guiding said pawls from retracted positions to arresting positions for arresting respective ones of said type members in different positions to present different ones of said type characters to said impression means the combination with said pawls of electromagnetic modules arranged side-by-side, each of said modules comprising a frame having first and second open guide cavities therein communicating with each other, an electromagnet carried by said frame, an interponent moveable in said first cavity and engageable with a said pawl, an armature moveable in said second cavity and engageable with said interponent, said armature being operable by said electromagnet to move said interponent to move said pawl from said retracted position to said arresting position, and the frame of each of said modules except a end one closing the said cavities in a neighboring one of said frames.

Claim 9

In a data printer having printing impression means, a plurality of type members arranged side-by-side, a plurality of type characters carried by said members, means for yieldably advancing said type members to carry said type characters past said impression means, stop pawls engageable with said type members whereby to arrest said members, and means for guiding said pawls from retracted positions to arresting positions for arresting respective ones of said type members in different positions to present different ones of said type characters to said impression means the combination with said pawls of electromagnetic modules arranged side-by-side, each of said modules comprising a frame having first and second open guide cavities therein communicating with each other, an electromagnet carried by said frame, an interponent moveable in said first cavity and engageable with a said pawl, an armature moveable in said second cavity and engageable with said interponent, said armature being operable by said electromagnet to move said interponent to move said pawl from said retracted position to said arresting position, and the frame of each of said modules except a end one closing the said cavities in a neighboring one of said frames.

Claim 10

The combination according to claim 7 comprising a third cavity in each of said frames for receiving a respective one of said electromagnets, the frame of the neighboring said module closing said third cavity.

Claim 11

The combination according to claim 7 wherein the centers of said first cavities are located in a common plane, and alternate ones of said electromagnets are located on opposite sides of said common plane.

Claim 12

The combination according to claim 7 wherein certain of the walls of said cavities guide the respective ones of said interponents and said armatures.

Claim 13

The combination according to claim 1 wherein said last mentioned means exerts a greater force against said pawl device than said spring.

Claim 14

In a data printer having a printing impression means, a type member having teeth thereon, a plurality of type characters carried by said member, cyclically operable means for yieldably advancing said member from an initial position to carry said type characters sequentially past said impression means, a stop pawl device having a part engageable with said teeth to arrest said member, means for guiding said pawl device from a retracted position to an arrestin position for arresting said type member in different positions to present different ones of said type characters to said impression means, and means for moving said pawl device from said retracted position to said arresting position, the combinatIon with said pawl device of spring means for yieldably maintaining said pawl device either in said retracted position or in said arresting position, and means operable by said cyclically operable means for returning said pawl device to said retracted position and for maintaining said pawl device in said retracted position independently of said spring means when said cyclically operable means is in said full cycle position.

Claim 15

In a data printer having a printing impression means, a type member having teeth thereon, a plurality of type characters carried by said member, cyclically operable means for yieldably advancing said member from an initial position to carry said type characters sequentially past said impression means, a stop pawl device having a part engageable with said teeth to arrest said member, means for guiding said pawl device from a retracted position to an arrestin position for arresting said type member in different positions to present different ones of said type characters to said impression means, and means for moving said pawl device from said retracted position to said arresting position, the combinatIon with said pawl device of spring means for yieldably maintaining said pawl device either in said retracted position or in said arresting position, and means operable by said cyclically operable means for returning said pawl device to said retracted position and for maintaining said pawl device in said retracted position independently of said spring means when said cyclically operable means is in said full cycle position.

Claim 16

In a data printer having a printing impression means, a type member having teeth thereon, a plurality of type characters carried by said member, cyclically operable means for yieldably advancing said member from an initial position to carry said type characters sequentially past said impression means, a stop pawl device having a part engageable with said teeth to arrest said member, means for guiding said pawl device from a retracted position to an arresting position for arresting said type member in different positions to present different ones of said type characters to said impression means, and means for moving said pawl device from said retracted position to said arresting position, the combination with said pawl device of a snap-over spring engageable with said pawl device, means supporting said spring to yieldably maintain said pawl device either in said retracted position or in said arresting position, and means operable by said cyclically operable means for returning said pawl device to said retracted position independently of said spring.

Claim 17

In a data printer having a printing impression means, a type member having teeth thereon, a plurality of type characters carried by said member, cyclically operable means for yieldably advancing said member from an initial position to carry said type characters sequentially past said impression means, a stop pawl device having a part engageable with said teeth to arrest said member, means for guiding said pawl device from a retracted position to an arresting position for arresting said type member in different positions to present different ones of said type characters to said impression means, and means for moving said pawl device from said retracted position to said arresting position, the combination with said pawl device of a snap-over spring engageable with said pawl device, means supporting said spring to yieldably maintain said pawl device either in said retracted position or in said arresting position, and means operable by said cyclically operable means for returning said pawl device to said retracted position independently of said spring.