US 5,148,067 AGranted

Latching linear motor

OwnerLaurence LaSotainventor

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Abstract

A linear motor provides stepwise, incremental advance of a moveable output member. First and second, spaced latches are movably coupled to the output member. A selectively energizible driver engages and moves the first latch into fixed engagement with the output member and continues to move the engaged first latch and output member a predetermined incremental advance distance. The second latch is biased to retain the output member in each successive incremental advance position while the first latch is being reset. In one embodiment, the driver is a solenoid having a movable plunger operably coupled to the first latch. In another embodiment, the drive is a motor having a rotatable output shaft with an eccentric cam mounted thereon. The eccentric cam engages the first latch to move the first latch into fixed engagement with the output member and to advance the fixedly engaged first latch and output member an incremental advance distance. Unlatch members are optionally coupled to at least the second latch for unlatching the second latch to enable the output member to be retracted in a direction opposite from the incremental advance direction.

Claims12

Dependent claims

A linear motor comprising:

a linearly movable output member;
an electromagnetic solenoid formed of a core and a coil, a plunger movably disposed within the core and movable from a first extended position with respect to the core and a second position in which the plunger is drawn into the core by magnetic attraction with the core when electric current is applied to the coil, the plunger being movable a predetermined distance from the first to the second position;
means for moving the plunger to the first extended position;
means, responsive to movement of the plunger from the first to the second position, for engaging and advancing the output member a distance substantially equal to the predetermined distance of movement of the plunger, the engaging and advancing means including:
first unidirectional latch means coupled to the output member and movable between a first position freely movable with respect to the output member and a second position in which the first latch means is fixedly engaged with the output member;
and
means for normally biasing the first unidirectional latch means to the first position;
the plunger being engageable with the first latch means and overcoming the force of the biasing means for moving the first latch means to the second position into fixed engagement with the output member when the plunger moves from the first to the second positions to advance the first latch means and the output member fixedly connected thereto a distance substantially equal to the predetermined distance of movement of the plunger;
means, coupled to the output member, for retaining the output member in an incremental advance position while the plunger is moving from the second to the first positions, the retaining means including:
second unidirectional latch means coupled to the output member and movable between a first position freely movable with respect to the output member and a second position fixedly engaged with the output member;
a stop fixedly mounted on the linear motor;
and
biasing means for urging the second latch means to a second position into engagement with the stop to prevent the output member from moving in a direction opposite from the incremental advance direction of movement of the output member;
and
a selectively energizable unlatch member movably engaged with at least the second latch means for moving at least the second latch means to the first position, when activated, to allow movement of the output member in a direction opposite from the incremental advance direction of movement of the output member.

12 more elements

A linear motor comprising:

a linearly movable output member;
an electromagnetic solenoid formed of a core and a coil, a plunger movably disposed within the core and movable from a first extended position with respect to the core and a second position in which the plunger is drawn into the core by magnetic attraction with the core when electric current is applied to the coil, the plunger being movable a predetermined distance from the first to the second position;
means for moving the plunger to the first extended position;
means, responsive to movement of the plunger from the first to the second position, for engaging and advancing the output member a distance substantially equal to the predetermined distance of movement of the plunger, the engaging and advancing means including:
first unidirectional latch means coupled to the output member and movable between a first position freely movable with respect to the output member and a second position in which the first latch means is fixedly engaged with the output member;
and
means for normally biasing the first unidirectional latch means to the first position;
the plunger being engageable with the first latch means and overcoming the force of the biasing means for moving the first latch means to the second position into fixed engagement with the output member when the plunger moves from the first to the second positions to advance the first latch means and the output member fixedly connected thereto a distance substantially equal to the predetermined distance of movement of the plunger;
means, coupled to the output member, for retaining the output member in an incremental advance position while the plunger is moving from the second to the first positions, the retaining means including:
second unidirectional latch means coupled to the output member and movable between a first position freely movable with respect to the output member and a second position fixedly engaged with the output member;
a stop fixedly mounted on the linear motor;
and
biasing means for urging the second latch means to a second position into engagement with the stop to prevent the output member from moving in a direction opposite from the incremental advance direction of movement of the output member;
and
a selectively energizable unlatch member movably engaged with at least the second latch means for moving at least the second latch means to the first position, when activated, to allow movement of the output member in a direction opposite from the incremental advance direction of movement of the output member;
and
a rocker member having first and second ends;
the first end being connected to and movable with the plunger;
the second end of the rocker member being connected to the unlatch member for moving the unlatch member to a position in which the unlatch member engages at least the second latch means for unlatching at least the second latch means from the output member.

16 more elements

A linear motor comprising:

a linearly movable output member;
an electromagnetic solenoid formed of a core and a coil, a plunger movably disposed within the core and movable from a first extended position with respect to the core and a second position in which the plunger is drawn into the core by magnetic attraction with the core when electric current is applied to the coil, the plunger being movable a predetermined distance from the first to the second position;
the output member extending co-axially through the core, coil and plunger of the solenoid;
means for moving the plunger to the first extended position;
means, responsive to movement of the plunger from the first to the second position, for engaging and advancing the output member a distance substantially equal to the predetermined distance of movement of the plunger, the engaging and advancing means including:
first unidirectional latch means coupled to the output member and movable between a first position freely movable with respect to the output member and a second position in which the first latch means is fixedly engaged with the output member;
and
means for normally biasing the first unidirectional latch means to the first position;
the plunger being engageable with the first latch means and overcoming the force of the biasing means for moving the first latch means to the second position into fixed engagement with the output member when the plunger moves from the first to the second positions to advance the first latch means and the output member fixedly connected thereto a distance substantially equal to the predetermined distance of movement of the plunger;
means, coupled to the output member, for retaining the output member in an incremental advance position while the plunger is moving from the second to the first positions, the retaining means including:
second unidirectional latch means coupled to the output member and movable between a first position freely movable with respect to the output member and a second position fixedly engaged with the output member;
a stop fixedly mounted on the linear motor;
and
biasing means for urging the second latch means to a second position into engagement with the stop to prevent the output member from moving in a direction opposite from the incremental advance direction of movement of the output member;
and
a selectively energizable unlatch member movably engaged with at least the second latch means for moving at least the second latch means to the first position, when activated, to allow movement of the output member in a direction opposite from the incremental advance direction of movement of the output member.

13 more elements

Dependencies are inferred from the claim text.