Cam guide drive mechanism for power-assisted chairs and the like
First Claim
1. A power-assist chair comprising:
- a base assembly;
a chair frame pivotally supported on said base assembly;
a seat assembly having a seat member, a seat back and swing link means for pivotally interconnecting said seat back and said seat member to said chair frame for reclining movement between an upright position and a reclined position;
a rotatable drive shaft extending transversely between opposite side portions of said chair frame;
a leg rest assembly supported from said chair frame and operatively coupled to said drive shaft for movement between a retracted position upon rotation of said drive shaft in a first direction, and an extended position upon rotation of said drive shaft in a second direction;
first follower means supported for pivotal movement on said base assembly and operably interconnected to said drive shaft;
second follower means supported for pivotal movement on said base assembly and operably interconnected to said swing link means;
linear actuation means for selectively actuating said swing link means and said leg rest assembly, said linear actuation means including a cam guide member adapted for translational movement and having first cam surface means engageable with said first follower means for causing corresponding rotation of said drive shaft in said second direction so as to extend said leg rest assembly, and second cam surface means engageable with said second follower means for causing corresponding movement of said swing link means so as to move said seat assembly to said reclined position; and
spring return means for biasing said first and second follower means in opposition to said first and second cam surface means, respectively, such that said leg rest assembly is biased toward said retracted position and said swing link means is biased toward said upright position.
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Accused Products
Abstract
The chair of the present invention includes a power-assisted linear actuation drive mechanism having a modified nut or "cam guide" which is linearly moveable upon rotation of the power screw for selectively actuating the lift and tilt linkage mechanism for causing forward lifting and tilting movement of the chair when the motor is operated in a first direction. Rotation of the screw shaft in a second opposite direction acts to lower the chair to the normal seating position. Continued rotation in the second direction causes sequential operative extension of the leg rest assembly followed by angular reclining movement of the chair. This sequential operation of the leg rest assembly and the reclining linkage are independent and may be easily disabled to selectively eliminate either of the features.
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Citations
25 Claims
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1. A power-assist chair comprising:
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a base assembly; a chair frame pivotally supported on said base assembly; a seat assembly having a seat member, a seat back and swing link means for pivotally interconnecting said seat back and said seat member to said chair frame for reclining movement between an upright position and a reclined position; a rotatable drive shaft extending transversely between opposite side portions of said chair frame; a leg rest assembly supported from said chair frame and operatively coupled to said drive shaft for movement between a retracted position upon rotation of said drive shaft in a first direction, and an extended position upon rotation of said drive shaft in a second direction; first follower means supported for pivotal movement on said base assembly and operably interconnected to said drive shaft; second follower means supported for pivotal movement on said base assembly and operably interconnected to said swing link means; linear actuation means for selectively actuating said swing link means and said leg rest assembly, said linear actuation means including a cam guide member adapted for translational movement and having first cam surface means engageable with said first follower means for causing corresponding rotation of said drive shaft in said second direction so as to extend said leg rest assembly, and second cam surface means engageable with said second follower means for causing corresponding movement of said swing link means so as to move said seat assembly to said reclined position; and spring return means for biasing said first and second follower means in opposition to said first and second cam surface means, respectively, such that said leg rest assembly is biased toward said retracted position and said swing link means is biased toward said upright position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A drive mechanism for use in power-assisted chairs of the type having a base, a chair frame supported on the base, an extensible leg rest assembly and a reclinable seat assembly having swing linkages pivotally interconnecting a seat back and a seat frame relative to the chair frame, said drive mechanism comprising:
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shaft means for operatively connecting said leg rest assembly to said chair frame, said shaft means operable for rotation in a first direction for moving said leg rest assembly to an extended position, and said shaft means rotatable in an opposite second direction for moving said leg rest assembly to a retracted position; a first follower assembly supported for pivotal movement on said base; first linkage means operatively coupling said first follower assembly to said shaft means; a second follower assembly supported for pivotal movement on said base; second linkage means interconnecting said second follower assembly to said swing link means; linear actuation means for selectively actuating said swing link means and said leg rest assembly, said linear actuation means including a cam guide member adapted for translational movement and having first cam surface means engageable with said first follower assembly for causing said shaft means to rotate in said first direction for extending said leg rest assembly, said cam guide member having second cam surface means adapted to engage said second follower assembly for causing said swing linkages to move said seat assembly from an upright position to a reclined position; first spring return means operatively interconnecting one of said first follower assembly and said leg rest assembly to said base for biasing sad leg rest assembly toward a retracted position; second spring return means operatively interconnecting said second follower assembly to said base for biasing said seat assembly to said upright position; and said linear actuation means including power operated means adapted for selectively moving said cam guide member in a first direction toward said first and second follower assemblies and in a second direction away from said first and second follower assemblies. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A power-assist chair comprising:
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a base assembly; a chair frame pivotally supported on said base assembly; lift means interconnecting said chair frame to said base assembly for movement between a lowered seating position and an elevated-tilted position; a seat assembly having a seat member, a seat back and swing link means for pivotally interconnecting said seat back an said seat member to said chair frame for reclining movement between an upright position and a reclined position; a rotatable drive shaft extending transversely between opposite side portions of said chair frame; a leg rest assembly supported from said chair frame and operatively coupled to said drive shaft for movement between a retracted position upon rotation of said drive shaft in a first direction, and an extended position upon rotation of said drive shaft in a second direction; a first follower assembly supported for pivotal movement on said lift means and operably interconnected to said drive shaft; a second follower assembly supported for pivotal movement on said lift means and operably interconnected to said swing link means; linear actuation means for selectively actuating said lift means, said swing link means and said leg rest assembly, said linear actuation means including a cam guide member adapted for translational movement and having first cam surface means engageable with said first follower assembly and second cam surface means engageable with said second follower assembly; said linear actuation means having power operated means adapted for selectively causing said cam guide member to move with respect thereto, whereby movement of said cam guide member in a first direction moves said chair frame from a neutral position defined by said chair frame being in said lower-seating position to said elevated-tilted position, movement of said cam guide member in a second direction with respect to said power operated means adapted to cause said lift means to lower said chair frame from said elevated-tilted position to said lowered-seating position, and wherein continued movement of said cam guide member in said second direction past said neutral position causes said first cam surface means to engage said first follower assembly for generating corresponding rotation of said drive shaft so as to extend said leg rest assembly, and continued movement of said cam guide member in said second direction causes said second cam surface means to engage said second follower assembly for generating corresponding movement of said swing link means so as to move said seat assembly to said reclined position; and spring return means for biasing said first and second follower assemblies in opposition to said first and second cam surface means, respectively, such that said leg rest assembly is biased toward said retracted position and said seat assembly is biased toward said upright position.
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Specification