Improvements in Trimming Attachments for Sewing Machines.
Year: 1896

page_text: Date of Application, 6th Jan., 1896-Accepted, 8th Feb., 1896
COMPLETE SPECIFICATION.
Improvements in Trimming Attachments for Sewing Machines.
1, WILLIAM HARVEY INSLEE. Manager of The Singer Manufacturing
Company, Kilbowie, Dumbartonshire, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
This invention, which relates to sewing machines, has for its object to provide a
trimming attachment of improved construction of the kind in which a vertical bar
cutter is employed and adapted to trim or cut the edges of the fabric with a
shearing action against a stationary cutter secured to the work plate. Hitherto in
this class of attachment considerable difficulty has been experienced in adjusting
the cutters relatively to each other to compensate for wear, and when in the case
of vibratory cutters provision has been made for maintaining the cutters in shearing
contact by a spring this has involved the blocking up of the work plate with the
adjusting mechanism and consequently interferes with the free run of the work
through the machine.
According to my invention I employ a stationary cutter composed of a single
blade of steel having a beveled cutting edge and which is held on edge on the
work plate by means of an adjustable holding plate which offers little or no
obstacle to the free run of the work; and I secure the moving shearing blade to
an adjustable block or plate guided and adapted to slide transversely in the
vertically reciprocating cutter bar, a spring being provided and arranged to press
the cutting blade into shearing contact with the stationary cutter in any position to
which the latter may be adjusted transversely to the line of stitching.
The invention is illustrated by the accompanying drawings in which
Figure 1 is a side elevation and Figure 2 an end elevation of a sewing machine
as fitted with my improved trimming attachment.
Figure 3 is a horizontal section of the cutter bar, showing the stationary cutter
on the work-plate.
Fig. 4 is a vertical section of the lower end of the cutter bar showing the cutters
in contact and
Fig. 5 is a similar view showing the spring pressed bar cutter drawn back out of
action.
The sewing machine itself is of ordinary construction having the usual work-
plate W and overhanging arm A and face plate B carrying the reciprocating
needle bar N with its needle n, cutter bar C and presser bar P with its presser
foot . On the work-plate W is fitted the lower knife or cutter d and cutter
holding plate D the lower edge of the cutter resting on the work-plate W
whilst its upper edge which is beveled or inclined is engaged by a corre-
spondingly beveled lip or undercut part d' of a flange piece D formed along the
edge of the holding plate D, the knife or cutter d being securely retained in place
by downward pressure between the lip and the work-plate. This pressure is
applied by means of a screw entered through a slot in the plate D and passing
into a hole tapped in the work-plate W, the head of the screw bearing on the to,
of the plate D. A guide pin or stud D' on the lower side of the plate D enters a
transverse slot in the work-plate; and by loosening the screw d the cutter holding
plate D may be adjusted across the work-plate to bring the cutter d more or less
near the needle so that the trimming of the goods may leave a more or less narrow
edge beyond the line of stitching. The loosening of the screw also permits of the
lower cutter or knife being withdrawn or being adjusted longitudinally. The

page_text: stationary knife or cutter being composed of a single blade of steel, having a
long inclined or beveled cutting edge is not only easily removed for sharpening but
may be readily replaced when worn out whilst the holding plate remains unaffected
by wear, and the knife and its holding flange being the only parts extending
appreciably above the surface of the work-plate and that in the line of the cutting
or trimming no obstacle is presented to the free run of the goods through the
machine.
The moving shearing cutter is composed of a thin steel blade having a
horizontal or slightly inclined or curved cutting edge at its lower end where it
bears closely against the cutting edge of the stationary knife d; and it is attached
by means of a screw c' entered through a slot in it to a plate or block 2 fitted in
the reciprocating cutter bar C. The bar or block 2 is formed with two projecting
studs or guide pins c³, e, one of which closely fits in an orifice drilled trans-
versely through the cutter bar C while the other e is surrounded by a helical
spring e and passes loosely into a hole or recess bored in the face of the cutter
bar C but not extending through it or having a closed end or shoulder against
which the end of the spring e may bear as shown at Figs. 4 and 5.
The coiled
spring e presses outwards the cutter carrying plate or block from the cutter
bar C and with it the cutter e so that the latter is caused to bear against the
stationary cutter d but the block e2 is prevented from slipping out by means of a screw/
entered into the end of the stud and having a head of a larger diameter than
that of the orifice in the cutter bar the said head bearing on the face of the
cutter bar C. By turning the screw f more or less the tension or pressure of
the coiled spring may be adjusted and the pressure which the cutter blade c
exerts against the face of the stationary knife d may be varied. As shown at
Fig. 5 the cutter block may be pressed back by hand and a forked gab piece y
may be inserted between the cutter bar and the head of the screw when it is
desired to withdraw the cutter e out of action for adjustment for removal of either
cutter.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is -
1. In a sewing machine a trimming attachment constructed and arranged to
operate substantially as described with reference to the annexed drawings.
2. In a sewing machine a trimming attachment composed of a stationary blade
adjustably secured upon the work plate and a reciprocating cutter fitted to the
cutter bar and maintained by spring pressure in shearing contact with the stationary
blade substantially as described.
3. In a trimming attachment for sewing machines a stationary cutter composed
of a steel blade maintained on edge on the work-plate by means of an adjustable
holding plate substantially as described.
4. In a trimming attachment for sewing machines a vertically adjustable shearing
cutter secured to a transversely adjustable plate or block fitted in the reciprocating
cutter bar and pressed outwards therefrom by means of a spring substantially as
described.
5. In a sewing machine the combination with the reciprocating cutter bar of the
plate or block carrying a cutter and having studs or guide pins, centering
orifices in the cutter bar, and a spring e interposed between the cutter bar and block
substantially as described.
Dated this 4th da
3000
WALLACE FAIRWEATHER,
Chartered Patent Agent,
62 Saint Vincent Street, Glasgow, Ageut for the Applicant.