Replaceable hook point and needle guard for sewing machine loop taker

A sewing machine loop taker is disclosed having a replaceable adjustable hook beak and needle guard fabricated as a integral element in which the dimensional relationships established in fabrication are not influenced by the means for securing or the provisions for adjustment of the element relatively to the loop taker.

DESCRIPTION 
Background of the Invention 
Field of the Invention: This invention relates to the field of sewing 
machine loop takers, and more particularly, to a novel loop taker 
construction with a replaceable adjustable insert formed integrally with 
both a hook point and a needle guard. 
DESCRIPTION OF THE PRIOR ART 
Loop takers which have been known heretofore with a replaceable integral 
hook point and needle guard arrangements have on the one hand involved 
such a degree of flexibility between the hook point and the needle guard 
that the shape and dimensional characteristics of the hook body materially 
influences the operational relationship between the hook point and the 
needle guard. On the other hand, such known arrangements have involved 
complex articulated construction requiring a multiplicity of parts. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide a sewing machine loop taker 
construction with a replaceable and adjustable hook point and needle guard 
formed as a single integral insert element which is adjustably secured to 
the loop taker body by a simple fastening means. 
It is also an object of this invention to provide a sewing machine loop 
taker construction with a replaceable adjustable insert including a hook 
point and a needle guard which are arranged in a predetermined 
relationship which remains uninfluenced by the dimensional characteristics 
of the loop taker body.

DESCRIPTION OF THE INVENTION 
In the accompanying drawings only a sewing machine loop taker is disclosed 
together with the replaceable adjustable hook point and needle guard 
insert thereof. For a complete disclosure of one manner in which a loop 
taker embodying the features of this invention may be supported, driven, 
and associated with other elements of a sewing machine to concatenate 
threads in the formation of stitches, reference is made to the U.S. Pat. 
No. 3,693,565, Sept. 26, 1972 of S. J. Ketterer. 
As illustrated in FIG. 1, 11 indicates generally a rotary loop taker for a 
sewing machine that includes a body portion 12 to which is secured a shaft 
13 defining an axis of rotation 14 for the loop taker when it is assembled 
into a sewing machine. The loop taker body portion 12 is formed with a 
circular rim 15 having a center of curvature substantially coincident with 
the axis of rotation 14. An inwardly facing bearing raceway 16 may be 
formed in the circular rim 15 to accommodate a bobbin case (not shown). 
As shown in FIG. 2, the circular rim 15 of the loop taker is not formed 
integrally with a hook beak or with a needle guard but instead is provided 
with a radial slot 20 in which to accommodate a replaceable and adjustable 
integral insert hook beak and needle guard portion indicated generally at 
30. The slot 20 has parallel sidewalls 21 and 22 and a bottom surface 23 
which occupies a plane perpendicular to the axis of rotation 14 of the 
loop taker. Preferrably the rim 15 of the loop taker adjacent to the slot 
20 is radially enlarged to provide greater thickness to the sidewalls 21 
and 22 of the slot 20. 
FIGS. 2, 3 and 4 illustrate the details of construction of the integral 
insert hook beak and needle guard portion 30. Preferrably the portion 30 
is fabricated from generally "U"-shaped stock including as best shown in 
FIG. 2, a lower limb 31, an upper limb 32 and a base section 33 joining 
the limbs. 
A hook beak 34 is formed on the upper limb 32 including a point 35 a throat 
36 and a stepped shoulder 37 which in the assembled loop taker provides 
for a continuation of the bearing raceway 16. The hook beak 34 over hangs 
the lower limb 31 opposite extremities 38 and 39 of which are made 
parallel and spaced apart a distance equal to the width of the slot 20 so 
that the hook beak portion may be slidably arranged therein for radial 
adjustment. That side of the lower limb 31 beneath the hook point is 
formed with a needle guard surface 40 which as shown in FIGS. 3 and 4 is 
in its fabrication located a distance X radially inwardly of the hook 
point. 
The lower limb 31 of the hook beak and needle guard portion is formed with 
one or more threaded holes 41 adapted to accommodate headed fastening 
screws 42 which pass through clearance holes 43 in the loop taker body 
portion 12 to secure the hook beak portion to the loop taker 11. The 
clearance holes provide for a limited range of radial adjustment of the 
hook beak portion relatively to the loop taker body portion. 
The principal advantage of the construction of this invention is that it 
provides for a high degree of accuracy and stability in the critical 
spacing relationship between the hook point and the needle guarding 
surface of the assembled loop taker in a simple, economical, and 
dependable manner. Once established by the fabrication of the hook beak 
portion 30 this dimensional relationship is immutable and it is not 
altered or varied in the assembly of the portion 30 onto the loop taker 
body nor is it changed when the radial position of the portion 30 is 
adjusted on the loop taker. 
Since the dimensions, shape and characteristics of the loop taker 11 do not 
influence the critical relationship between the hook beak and the needle 
guard, the loop taker body portion may be fabricated using materials and 
methods chosen for other attributes, not necessarily related to the highly 
critical accuracy of the hook beak to needle guard dimension and this also 
contributes significantly to the successful operating characteristics and 
cost effectiveness of the construction of this invention.