Claims
- 1. A bidirectional proportional spacing carrier moving mechanism for a carrier of an electric typewriter, comprising:
- a ratchet wheel with teeth having a predetermined pitch for determining incremental proportional spacing units;
- means coupling said ratchet wheel to said carrier for bidirectional rotation in synchronism with bidirectional linear movement of said carrier;
- first force exerting means for urging said carrier in a first direction to cause said ratchet wheel to be urged in a given rotational direction;
- detent means normally engaged with said ratchet wheel for preventing rotation thereof in said given direction, to thereby prevent movement of said carier in said first direction;
- first control means for momentarily disengaging said detent means from said ratchet wheel to permit rotation of said ratchet wheel in said given direction by said first force exerting means;
- an incremental spacing control member having a first end pivotally mounted adjacent said ratchet wheel, and a stop engaging surface remote from said wheel;
- a pawl normally engaged with one of said teeth and pivotally mounted on said control member, for preventing rotation of said ratchet wheel in said given direction when said detent means is disengaged therefrom;
- a plurality of stop members disposed in mutual alignment adjacent said stop engaging surface, at least two of said stop members being selectively movable in and out of the path of movement of said stop engaging surface,
- said stop members permitting incremental rotational movement of said stop engaging surface, pawl and ratchet wheel in said given direction and linear movement of said carrier in said first direction, by a distance corresponding to a desired number of proportional spacing increments;
- second force exerting means for urging said control member to rotate in a direction to move said stop engaging surface away from said stop members and to cause said pawl to rotate said ratchet wheel in a direction opposite to said given direction, to drive said carrier for linear movement in a second direction opposite to said first direction; and
- releasable means for momentarily rotating said control member against the force exerted by said second force exerting means to move said pawl a distance corresponding to a desired number of second direction spacing increments, until said stop engaging surface engages one of said stop members,
- said second force exerting means acting upon release of said control member by said releasable means to move said carrier in said second direction by said desired number of second direction spacing increments.
- 2. The carrier moving mechanism according to claim 1, wherein said stop members include at least one stationary stop more remote from said stop engaging surface than the other ones of said stop members.
- 3. The carrier moving mechanism according to claim 1 or 2, further comprising upper case and lower case switch means for defining the case of a character to be traversed by said carriage, and second control means coupled to said switch means for selectively moving said stop members in accordance with said character case.
- 4. A bidirectional proportional spacing carrier moving mechanism for a carrier of an electric typewriter, comprising:
- rotatable ratchet means;
- means coupling said ratchet means to said carrier for bidirectional rotation in synchronism with bidirectional linear movement of said carrier;
- first force exerting means for urging said carrier in a first direction to cause said ratchet means to be urged in a given rotational direction;
- detent means normally engaged with said ratchet means for preventing rotation thereof in said given direction, to thereby prevent movement of said carrier in said first direction;
- first control means for momentarily disengaging said detent means from said ratchet means to permit rotation of said ratchet means in said given direction by said first force exerting means;
- a movable incremental spacing control member having a stop engaging surface;
- means coupled between said control member and said ratchet means, for preventing rotation of said ratchet means in said given direction when said detent means is disengaged therefrom;
- adjustable stop member means disposed adjacent said stop engaging surface;
- said stop member means permitting incremental movement of said stop engaging surface and incremental rotational movement of said ratchet means in said given direction and linear movement of said carrier in said first direction, by a distance corresponding to a desired number of proportional spacing increments;
- second force exerting means for urging said control member away from said stop member means to cause said ratchet means to rotate in a direction opposite to said given direction, to drive said carrier for linear movement in a second direction opposite to said first direction; and
- releasable means for momentarily rotating said control member against the force exerted by said second force exerting means to move said stop engaging surface into engagement with said stop member means,
- said second force exerting means acting upon release of said control member by said releasable means to move said carrier in said second direction by said desired number of second direction spacing increments.
Parent Case Info
This is a division of application Ser. No. 732,973, filed Oct. 15, 1976, which is a division of U.S. Ser. No. 213,045 filed Dec. 28, 1971 and now U.S. Pat. No. 3,993,179 dated Nov. 23, 1976.
US Referenced Citations (8)
Non-Patent Literature Citations (1)
Entry |
IBM Technical Disclosure Bulletin, "Integrated Forward and Backspace Mechanism," Miles et al., vol. 12, No. 12, May 1970, pp. 2189-2191. |
Divisions (2)
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Number |
Date |
Country |
Parent |
732973 |
Oct 1976 |
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Parent |
213045 |
Dec 1971 |
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