Improvements in or-connected with Rotary Loopers and Under-thread Carriers for Sewing Machines.
Year: 1895

page_text: Date of Application, 4th June, 1895-Accepted, 6th July, 1895
COMPLETE SPECIFICATION.
Improvements in or-connected with Rotary Loopers and Under-thread
Carriers for Sewing Machines.
I, JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of London
Gentleman do hereby declare the nature of this invention (which has been com-
municated to me from abroad by Heinrich Springmann of 40 Hindersinstrasse 3
Berlin N.W. in the Empire of Germany Patent Agent) and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement :-
In sewing machines provided with rotary loopers in which stationary under-
thread carriers or spool cases are situated the guiding surfaces of both of these parts
must be provided with notches (such as are shewn at A and B in Figures 1 and 2
of the accompanying drawings) to enable the upper thread, which is to be formed
into a loop, to slip over freely without friction. These notches have however
presented difficulties in the operation of the machine. One drawback in particular
owing to defective guiding of the moving parts is especially noticeable when the
looper assumes either of the positions in which only about half of the guiding parts
are in
proper engagement, and especially when the guiding parts have become worn
through prolonged use. This inconvenience is particularly noticeable at the time-
when, in consequence of the upper thread being taken up, a one-sided pull is
exercised upon the thread carrier as the said thread carrier is thereby liable to be
displaced and to be the cause of serious disturbance in the general operation of the
machine.
The present invention (which I will dit reference to the accompanying
drawings) is intended to afford an effective remedy for the disadvantages stated.
Figures 1, 2 and 3 of the accompanying drawings represent in side views of the
looper and under-thread carrier and in vertical section of the looper with the thread
carrier in position, the old guiding arrangement so that by comparing these figures
with the improved construction shewn by the other figures this invention and its
advantages will be readily understood.
Figures 4 to 6 represent arrangements according to this invention, Figure 4
being a section of one form, Figure 5 sections of two varieties of another form and
Figure 6 another modification in section with separate side views (I and II) of the
looper and of the thread carrier or spool case.
It will be seen by reference to these Figures 4, 5, and 6 that the invention
mainly consists in providing both the rotating looper and the stationary spool
case S with means for preventing the aforesaid undesirable displacement of
the thread carrier by abandoning or supplementing the hitherto usual rectangular
sectional area a (Figure 3) of the guiding surfaces and employing a formation or
arrangement of the said guiding surfaces which will prevent radial displacement of
the thread carrier or spool case relatively to the looper, for which purpose the
circular shape in transverse section of the guiding surfaces which engage together
shewn at a Figure 4 or the tooth shaped arrangements as shewn in reverse
positions at a Figure 5 may be used.
In order to enable the looper and the thread carrier or spool case to be put
together the looper may be made in two pieces G and G¹ fastened together by
screws or in other convenient manner the part G being firmly secured to the
rotating shaft R.
Figure 6 shews the arrangement according to this invention situated on one side-

page_text: in addition to guiding surfaces of the ordinary or any suitable kind. I shewing in
front view the looper separately and II shewing in rear view the thread carrier or
spool case separately the projection P serving to hold the thread carrier or spool
case in place as usual. In this case an annular rib a is provided on the part Ġ of
the looper and this engages in a corresponding groove a³ in the thread carrier or
spool case S thereby avoiding any radial displacement and thus securing the said
carrier in proper relative position. It will of course, be understood that both the
said rib a* and the projections forming the groove a³ will have to be cut away or
notched at A' and B¹ to ensure the free passage of the upper thread loop.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
A rotary looper and stationary under-thread carrier or spool case for sewing
machines having guiding surfaces so arranged as to prevent radial displacement
of the thread carrier or spool case substantially as herein before described and
illustrated under several modifications in the accompanying drawings.
Dated this 4th day of May 1895.
JOHNSONS & WILLCOX,
Agents.