High lift sewing machine
AssigneePorter Sewing Machines, Inc.
InventorsCharles E. Mulcahey, John J. Kirby, Michael R. Porter
Life of this patent
Estimating the term…
Abstract
The invention comprises improvements to sewing machines for increasing the throat clearance of the machine. The improvements relate to 1) modifications to mechanical components of the machine to increase the throw and upper travel limits of the presser foot, upper feeding foot, needle and spreader, 2) an adjustment for allowing the speed of the upper walking foot to be variable relative to the speed of the lower walking foot, and 3) an improved biasing spring for biasing the presser foot downward.
Claims7
A walking foot assembly for a sewing machine for advancing material between stitches, comprising:
- first and second lower walking feet mounted on first and second lower walking foot bars, respectively,
- an upper walking foot positioned directly above said second lower walking foot and mounted on an upper walking foot bar,
- means for driving said first lower walking foot bar and foot to travel through an elliptical path at a first speed,
- means for driving said second lower walking foot to travel through an elliptical path at a second speed different from said first speed,
- a member directly connecting said upper walking foot bar to said second lower walking foot bar such that the motion of said upper walking foot bar and foot is responsive to the motion of said second lower walking foot bar.
A walking foot assembly for a sewing machine for advancing material between stitches, comprising:
- first and second lower walking foot,
- an upper walking foot positioned directly above said second lower walking foot, means for driving said first lower walking foot to travel through an elliptical path at a specified speed,
- means for driving said second lower walking foot to travel through an elliptical path at a speed different than the speed of said first lower walking foot;
- and
- an arm fixedly attached to said lower walking foot driving means, said arm passing through a slot in said first lower walking foot driving means, whereby said arm can slide freely in said slot when said speed of said first lower walking foot driving means is different than the speed of said second lower walking foot driving means.
Dependencies are inferred from the claim text.