Presser foot with workpiece guide for sewing machines

A presser foot for sewing machines including a body portion formed with a recess at a lower end thereof and a threaded hole above the recess, a knob having a cylindrical member having a large diameter at a first end and a small diameter at a second end, the knob being formed with a concaved portion between the ends and an axial through hole with a counter sink at the first end, the knob being rotatably mounted on the body portion by a countersunk bolt which extends through the axial through hole into the threaded hole thereby forming a generally semi-circular cavity, whereby the feeding of a workpiece through the presser foot can be facilitated.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an improved presser foot for sewing machines and 
in particular one which can facilitate the feeding of a workpiece. 
2. Description of the Prior Art 
The conventional presser foot for sewing machines (see FIGS. 4 and 5)) 
includes a body portion 30 which is provided with a pair of feet 31 at the 
lower end. A recess is formed between the two feet 31 for the passage of 
the raised seam of a workpiece 20 such as a bag or the like. However, it 
is difficult to feed the workpiece through such a presser foot thereby 
making it uneasy to feed the workpiecce along a straight line. 
Hence, another presser foot (see FIG. 6) has been developed to obviate this 
drawback. The presser foot includes only one foot and a semi-circular 
recess at the bottom. Nevertheless, the workpiece is often scratched by 
the presser foot when feeding therethrough. Furthermore, although the 
presser foot has only one foot, the friction between the single foot and 
the workpiece still render it difficult to feed the workpiece along a 
straight line. 
In addition, the above-mentioned two conventional presser feet have to be 
changed in order to adapt to raised seams of different sizes and so the 
user must purchase a set of presser foot to serve different purposes. 
Therefore, it is an object of the present invention to provide an improved 
presser foot for sewing machines which can obviate and mitigate the 
above-mentioned drawbacks. 
SUMMARY OF THE INVENTION 
This invention relates to an improved presser foot for sewing machines. 
It is the primary object of the present invention to provide a presser foot 
for sewing machines which can facilitate the feeding of a workpiece. 
It is another object of the present invention to provide a presser foot for 
sewing machines which can guide a workpiece to move along a straight line. 
It is still another object of the present invention to provide a presser 
foot for sewing machines which is practical in use. 
It is still another object of the present invention to provide a presser 
foot for sewing machines which is simple in construction. 
It is a further object of the present invention to provide a presser foot 
for sewing machines which is low in cost. 
Other objects of the invention will in part be obvious and in part 
hereinafter pointed out. 
The invention accordingly consists of features of constructions and method, 
combination of elements, arrangement of parts and steps of the method 
which will be exemplified in the constructions and method hereinafter 
disclosed, the scope of the application of which will be indicated in the 
claims following.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
For the purpose of promoting an understanding of the principles of the 
invention, reference will now be made to the embodiment illustrated in the 
drawings. Specific language will be used to describe same. It will, 
nevertheless, be understood that no limitation of the scope of the 
invention is thereby intended, such alterations and further modifications 
in the illustrated device, and such further applications of the principles 
of the invention as illustrated herein being contemplated as would 
normally occur to one skilled in the art to which the invention relates. 
With reference to the drawings and in particular to FIGS. 1, 2 and 3 
thereof, the presser foot according to the present invention mainly 
comprises a body portion 10, a knob 14 and a countersunk bolt 13. 
The body portion 10 is formed with a recess 11 at the lower end and a 
threaded hole 12 above the recess 11. 
The knob 14 is a cylindrical member having a large diameter at the left end 
and a small diameter at the right end (with respect to FIG. 1). Further, 
the knob 14 is formed with a concaved portion between its both ends and an 
axial through hole with a counter sink at the right end. The knob 14 is 
rotatably mounted on the body portion 10 by the countersunk bolt 13 which 
extends through the axial through hole into the threaded hole 12 of the 
body portion 10. As the knob 14 is arranged on the body portion 11, a 
generally semi-circular cavity 11 will be formed by the concaved portion 
of the knob and the recess 11 of the body portion 10. 
When used for stitching a bag 20 or the like, the raised seam in which is 
inserted a round rod 21 is fitted within the cavity 11. The cavity 11 is 
also used for guiding the bag 20. As the knob 14 is rotatably mounted on 
the body portion 10, the knob 14 will be rotated when the bag is fed 
through the cavity 11 hence largely decreasing the friction therebetweeen 
and therefore making it easy to operate. 
Furthermore, the knob 14 can be easily replaced with one having a size 
adapted to receive the seam of a bag or the like. In other words, it is 
only necessary to replace the knob without changing the whole presser foot 
when required to serve different kinds of workpieces. 
The invention is naturally not limited in any sense to the particular 
features specified in the forgoing or to the details of the particular 
embodiment which has been chosen in order to illustrate the invention. 
Consideration can be given to all kinds of variants of the particular 
embodiment which has been described by way of example and of its 
constituent elements without thereby departing from the scope of the 
invention. This invention accordingly includes all the means constituting 
technical equivalents of the means described as well as their 
combinations.