IMPROVEMENTS IN SEWING MACHINES
Year: 1879

page_text: LETTERS PATENT to James McAllister, of the City of Chicago, in the County
of Cook, and State of Illinois, in the United States of North America, for the
Invention of "IMPROVEMENTS IN SEWING MACHINES.”
Sealed the 19th December 1879, and dated the 6th October 1879.
COMPLETE SPECIFICATION filed by the said James McAllister at the Office
of the Commissioners of Patents on the 6th October 1879.
JAMES MCALLISTER, of the City of Chicago, in the County of Cook, and State
of Illinois, in the United States of North America. "IMPROVEMENTS IN SEWING
MACHINES."
Figure 1 is an isometrical view of my machine; Figure 2 is a plan view of the
lower side of the same; Figure 3 is an elevation of the front side, a portion of
the stationary arm being removed; Figures 4, 5, and 6 are side elevations of the
mechanism employed for operating the needle-bar, and show respectively the
positions when said needle bar has first reached its lowest point, when it has been
raised to slacken the thread, and when it has again returned to its lowest position;
Figure 7 is an isometrical view of the shuttle race and carrier separated from the
machine; Figure 8 is a cross section of said parts taken on line x, x, of Figure 7;
Figure 9 is a central longitudinal section of the base plate, and shows in side eleva-
tion the rear side of the mechanism employed for operating the shuttle carrier;
Figures 10, 11, and 12 are like views of the said mechanism at different points of
the movement of said shuttle-carrier; Figure 13 is a plan view of the lower side of
the mechanism for operating the feed-bar; Figure 14 is a section, upon line a¹, x',
of Figure 13; Figure 15 is an elevation of the right hand end of the machine, the
base-plate and stationary arm being broken away so as to show the operating
mechanism; Figure 16 is an isometrical view of the rear side of the head; Figure 17
is an elevation of the front side of the same, the front section being removed so as
to afford a view of the interior; Figures 18 and 19 are respectively vertical sections
of the head upon lines passing through the presser-bar screw and the tension spring;
Figures 20 and 21 are horizontal sections of said head upon lines x2, x², a³, x³, respec-
tively of Figure 17; Figure 22 is a side elevation of the housing or head containing the
needle-bar, take-up, and so forth; Figure 23 is a like view of the same, the covering
•

page_text: plate being removed so as to show the construction of the tak up; Figure 24 is an
isometrical view of the presser-foot and the lower end of the presser-bar, and shows
the means employed for connecting the same together; Figure 25 is a horizontal
section of the same upon line z, z, of Fig. 24; and Figure 26 is a section of one at
the bearings of the machine, and shows the means employed for compensating for
end wear.
Letters of like kind refer to like parts in each of the Figures.
The design of my Invention is to increase the efficiency and lessen the expense
of sewing machines, and to this end it consists principally in operating the vibrating
arm, and further in the means employed for operating the shuttle carrier; thirdly,
in the means employed for imparting longitudinal motion to the feed-bar; fourthly,
in the means employed for imparting vertical motion to said bar; fifthly, in the
means employed for regulating the length of the stitch; sixthly, in the means
employed for giving pressure to the tension plate; seventhly, in the construction
of and mechanism for operating the tension plate; eighthly, in the means employed
for applying spring pressure to the presser-bar; ninthly, in the means employed for
connecting the presser foot to or with the presser-bar; and, finally, it consists in the
means employed for pivoting various parts of the machine, whereby lost motion
caused by wear may be taken up.
In the annexed Drawings A represents the base plate of my machine, from one
end of which at its transverse centre extends upwards a square hollow-shaft B that
vertically decreases in horizontal dimensions from its base to its upper end. From
the upper end of the boss B, at one side of its transverse centre, an arm C extends
in a curve upward and forward, and thence horizontally forward nearly to the front
end of the base plate A, and at its forward end is provided with a housing or
head D; that within its front and rear-sides is provided with vertical grooves d and
d¹, which respectively receive the needle-bar E and presser-bar F, each of which
bars is formed of a flat rectangular bar of steel. For convenience of construction
the head D is formed in two parts, which separate upon a vertical central line that
has a right angle to the line of the fixed arm C. The rear section is permanently
attached to and forms part of said fixed arm, while the outer section is secured
in place by two screws d², which pass through the same, and have their inner
threaded ends contained within correspondingly threaded openings in said rear
fixed section. The lower end of the needle-bar E is provided at its front side with
a boss e through which is a vertical opening e¹ that receives a needle G, while at
its front side said boss has a threaded opening which receives a thumb-screw H,
that operates to confine said needle in its place. At or near the longitudinal centre
of the needle-bar E, upon its front side, is a cylindrical boss e¹, through which and
through said bar is provided a round opening e¹ that receives a correspondingly
shaped stud I, that loosely fills the same.
Immediately in rear of said needle-bar the stud I has an enlargement i, while
upon the rear side of such enlargement is provided a boss i¹ which vertically has
about the dimensions of said stud, and in a line with the fixed arm C has con-
siderably increased dimensions, and from said enlargement projects rearward a
distance about equal to the length of said stud. The needle-bar E is caused to
reciprocate vertically by means of an arm K, which has the general form of a right
angle, and is pivoted near the intersection of its arms to or upon the side of the
fixed arin C, as shown, and at its front end extends into a recess which is formed
engages with the boss i¹. If now the arm K be caused to oscillate upon its pivotal!
within the rear side of the head D, where said end is provided with a slot k that
bearing the needle-bar E will be moved vertically within the head D, during which
movement the stud I will turn within said needle-bar, as said vibrating
arm changes
its angle, while the boss will slide back and forth within the slot has the end of
said arm moves within the arc of a circle. Motion is imparted to the vibrating
bearings L, L, and beneath and at right angles with the length of the base plate A,
arm K by the following mechanism: - Journalled horizontally within suitable 5
is a shaft M, which is provided upon its rear end with a balance-wheel N and band

page_text: pulley n, and at its opposite end, which terminates at or near the transverse centre
of said base plate, has secured a disc O.
Journalled in rear of and somewhat higher and parallel with shaft M is a short
shaft P, which extends from the front end of the former towards the front side of
5 the base plate A, and is provided with an arm p that extends radially forward
against or nearly against the plate O. Extending longitudinally within the arm p
is a slot p' which has parallel sides and receives and contains a square block Q that
pin o passing through a round opening q at the centre of said block has its inner
10 threaded end contained within a correspondingly threaded opening in the disc O, and
when the latter revolves with the shaft M moves said block in a circular line, and
causes said arm p to vibrate vertically, during which operation said block slides back
and forth within its slot p' a distance equal to the diameter of the circle described
by it. The lower end of the vibrating arm K extends forward to or slightly below
15 the axis of the shaft M and is connected with the outer end of the arm p by means
of a short bar R which has its ends pivoted upon said parts K and p, as shown
in Figs. 3 and 5. If now the shaft M is caused to revolve the movements of the
pivoted arm will by means of the bar R cause the vibrating arm K to oscillate upon
its pivoted bearing and to move the needle bar E vertically within its head. In
20 Figure 3 is shown the position of the operative mechanism when the needle-bar is at
its highest point. The sliding-block Q exerts least power upon the needle-arm K, as
said block nears the rear end of the slot p¹ of the arm p, but when said parts occupy
such position the needle-bar E is at or near the upper limit of its motion, the take-
pl is at rest and but little power is required to move said needle-bar. As the
25 sliding-block moves away from the pivotal bearing of the arm p towards the outer
end of the slot p¹ the needle-bar E descends and requires a constantly increasing
moving power which increase of power is supplied by said block Q and crank-pin o,
their effective force being augmented as they near the outer end of said arm p until
the maximum is attained as the needle G passes through the fabric being operated
30 upon, the relative positions of parts being shown in Figure 4, said block Q being
at the outer end of said slot p¹, and the said crank-pin o substantially in line with
the pivotal axis of the bar R. From the position shown in Fig. 4 the downward
and rearward motion of the crank-pin o causes the needle to rise and loosen the
thread so as to enable the shuttle to more easily pass through the loop, which rise
35 continues until said pin is in a line radially, having a right angle to a line passing
through the axis of the shaft P, and the pivotal connection between the end of the
arm P and the lower end of the bar R, as seen by the interrupted lines in Fig. 5,
after which the further movement of said crank-pin causes said needle to again
descend until, as shown in Fig. 6, said crank-pin is in line with the pivotal axis of
10 said bar R, when a further movement carries said needle upward to the position first
described. In addition to the advantage obtained in thus adapting the power of the
operating mechanism to the requirements of the needle the construction described
causes the latter to descend and pass through the cloth at a moderate velocity and
to rise rapidly after having done its work, whereby the durability and efficiency of
15 said operative mechanism are materially enhanced.
up
The shuttle-race, as seen in Figs. 7 and 8, consists of a plate S having a vertical
longitudinal slot &, and at one side of the same within its upper side is provided a
shuttle-groove 8'. Within the slots slides the carrier T which is composed of a
flanged block that embraces the lower face of the shuttle-race S and extends upward
10 through the slot 8, and a plate t that is secured upon the upper side of said block
extends over the upper face of said shuttle-race, and at each end is provided with
an arm t' which extends over the groove s¹ and engages with one end of an ordinary
shuttle U, said plate t is secured upon said block by means of screws which pass
55 to adjust the position of the shuttle in relation to the needle. The shuttle race S
through elongated openings and enable said plate to be adjusted lengthwise so as
is secured to or upon the lower side of the base-plate by means of suitable screws.
The shuttle carrier is operated as follows:-

page_text: Pivoted within the upper end at the rear side of the
Site
to the needle-arm K is a lever V which has a long and a short arm that have
nearly a right angle to each other, the short arm being uppermost; pivoted at
downward and is connected with and forms part of the strap w that encircles an
the angle of the lever V is one end of a bar W which from thence extends
eccentric X which is secure
upon and revolves with the shaft M.
To the lower
end of the lever V is pivoted one end of a bar Y, which from thence extends for-
ward and has its opposite end pivoted upon an arm ill that extends laterally
outward from the rear end of the shuttle-carrier T. If now the driving-shaft is
caused to revolve the shuttle-carrier T will be moved back and forth within the
shuttle-race S, the relative position of parts between the rear and forward
When the shuttle
limits of motion of said carrier being shown in Figs. 9 to 12.
carrier moves forward the lower end of the lever V which is then below the
former rises as it advances and thus lessens the velocity with which it moves
said carrier, while upon the return movement the end of said lever is not only
passing rearward but downward, and causes said carrier to pass quickly from the
front to the rear limit of its stroke, the time required for such rearward movement
being about one half that which is occupied by the forward movement of said carrier.
In consequence of the unequal velocity of the shuttle carrier upon its forward and
rearward movements the shuttle is caused to pass more quickly through the loop
than would otherwise be possible where a continuous movement of a crank or an
eccentric is employed.
1
The feed bar Z has the form in side-elevation, seen in Fig. 14, its engaging
portion = being serrated upon its upper side and provided with a longitudinal
slot z¹ for the passage of the needle; while from the rear end of said serrated
portion said bar extends downward below the base plate A, thence horizontally
rearward for a short distance, and from thence rearward to its end is flattened hori-
zontally, and has such flattened portion dropped downward as shown in said Figure.
The serrated portion z of the feed-bar Z is contained within a corresponding
opening within the base-plate A, and is free to move longitudinally the necessary
distance; while the portion below said plate is contained within a housing A¹,
which is secured upon the lower side of said base plate, and is provided with a
groove a¹ that receives the end of said bar and enables it to move freely,
vertically, and longitudinally. Longitudinal motion is imparted to the feed-
bar Z by the following mechanism :-Within a suitable groove that is formed in
the lower side of the base plate A is a flat bar B' that is capable of sliding
lengthwise nearly in line with the shuttle-race, and at its rear end is provided
with a block b¹ that is pivoted in said end, and has one of its ends flattened to
fit into a narrow slot w¹ which extends lengthwise of the bar W, the arrange-
ment being such as to cause said bar B₁ to reciprocate longitudinally by the
forward and backward motion of said bar W as the eccentric X revolves. From
the front end of the bar B' an arm 61 extends laterally toward the front side
of the machine, and to its end has pivoted one end of a bar C', which from thence
extends forward within a groove in the base plate A into the housing A¹ above the
feed-bar Z, and immediately in rear of the vertical portion of the same.
the edge of the bar C¹, towards the rear side of the machine, is formed a recess c',
which at its front end has a forward and an outward sloping face, which inclined
face and the edge of the bar between the same and the forward end of said bar bears
against a roller D' that is pivoted within one end of a bar E', which extends for-
ward within the housing A¹ in a line with the feed-bar Z, and is capable of longi-
tudinal adjustment by means of a screw F1 that is swivelled within the downward
projecting edge of the base plate A, and has its threaded end contained within a
correspondingly threaded axial opening in said bar.
Within
The feed-bar Z is pressed against the bar C, and the latter held with a yielding
to reciprocate longitudinally by the movement of the bar B' its recess c¹ will be
brought opposite to the roller D' each time said bar moves forward. If the roller D'

page_text: such rearward movement of the latter will cause the inclined face of its recess to be
is now moved inward until its periphery enters the groove which contains the bar C¹,
brought into contact with said roller, and thereby said bar C¹ with the feed-bar Z
will be moved toward the rear side of the machine, the degree of such motion being
governed by the distance to which said roller extends into said groove. Upon
the return movement of said bar C¹ the inclined face of its recess c¹ will pass out
of engagement with said roller D', when the spring G¹ will move said bar and said
feed-bar to their normal position once more.
111
Vertical motion is imparted to the
feed-bar Z by the following means:- Journalled at one end within a bearing at or
near the rear end of the base plate A, and at its opposite end within the housing A¹,
is a shaft H', which at its front end is provided with a crank-arm h that extends
towards the front side of the machine beneath the horizontally flattened portion of
the feed-bar Z, and at its outer end is provided with a roller h². At the rear end
of the shaft H¹ is a second crank h¹, which extends laterally toward the rear side of
the machine, and then downward in rear of the driving shaft M and adjacent to the
inner face of the disc O, at which point said crank arm is provided with a roller h¹¹1
that has its axis parallel with said face. Within and upon the inner face of the
disc O is formed a cam track o', upon which rests the roller 111, said track having
such relative elevation above and depression below the face of said disc as to
impart to the crank-arm h', and through the same and the shaft H¹ to the crank-
arm h, sufficient motion to cause the outer end of the latter to raise the feed-bar
the desired height above the needle-plate. The shape of the cam-track and the
position of its elevated portion with relation to the crank-pin o causes the feed-bar
to rise at the commencement of its rearward movement and to remain in such
elevated position until it has reached the limit of motion in such direction, while
during the forward motion of said feed-bar the elevating mechanism is motionless.
In order that the feed-bar Z may preserve its horizontality during its movement
its rear portion is provided with a slot z", which, as shown in Fig. 14, receives a
pin 2 that passes through said slot and through the contiguous portion of the
housing A¹. As thus arranged a forward movement of said feed-bar will cause its
rear end to rise at the same time and to the same height as the front end.
The upper thread I is fed from a spool which is placed over a stud K¹ that
extends upward from the rear portion of the stationary arm C¹, from which spool
said thread passes forward and then upward beneath a plate L' that is fitted
loosely into a horizontally grooved plate M², which is secured upon the side of the
head D next to said spool and at the upper end of said head. The plate L' is held
with a yielding pressure within the groove by means of a screw N¹ which passes
horizontally through said parts, and upon its outer end is provided with a thumb-
nut n¹, and at its inner end has upon opposite sides narrow vertical grooves
that receive the forked end of a flat spring O¹. From said screw N¹ said spring O¹
extends downward to or near the lower end of the head D, and has its lower end
contained within a correspondingly shaped recess which is formed within the con-
tiguous section of said head, the lower screw d' of said head passing through an open-
ing in the lower end of said spring. The spring O¹ has such shape longitudinally
as to cause its upper end to draw inward upon the screw N', so as to hold the
plate L'against the plate M' with a yielding pressure, the degree of which pressure is
governed by the position of the nut n'. By turning said nut in one direction such
pressure is increased, while by turning it in an opposite direction such pressure is
decreased, the result of which pressure is to give the thread I' such tension as may be
necessary in order to permit of the formation of a perfect stitch. A notch m¹ is formed
between the upper of the flanges which form the groove of the plate M', through
which the thread I passes upward, while a notch ' within the lower edge of the
plate L' receives said thread from the spool. From the tension device described
the thread passes upward through an eye el which is provided upon the front side
at the upper end of the needle-bar E, from thence downward to and through a second
from thence rearward and downward to and through the needlo G. The take
eye which projects from the front side below the vertical centre of the head D,
up Pl

page_text: is composed of a plate which has the form seen in
18
contained within a recess that is formed in the front side of the head D, and at
its inner side is near the outer face of the needle-bar E.
111
At its upper end the take-up P¹ is pivoted within its recess, while its lower end
is free to move a distance slightly less than the width of the head D, which move- 5
ment is effected by means of a stud k¹, which extends forward from the outerside of
the vibrating arm K, just in rear of the needle-bar E, and engages with a slot pl
that extends longitudinally from near the upper end to a point below the centre of
said take-up. The upper half of the slot p₁ll is substantially vertical when the
lower end of the take-up is at its rear limit, while from its centre downwards said l
slot has a rearward inclination. In use, the lower end of the take-up is at the
forward limit of its motion when the needle is at its lowest point, and as said
needle rises said take up moves rapidly rearward and reaches the rear limit of its
motion just before said needle emerges from the fabric being operated upon, from
which time until the needle reaches the same point upon its downward movement 1
said take-up remains stationary and then moves rapidly forward to its forward
limit of motion. The operation of the take-up being independent of springs is
positive and its retraction of the thread is thus uniform, a result which could not
be secured by a spring take-up or by the use of a spring for moving the take-up
rearward. The recess within the head D, in which is placed the take-up P₁, is 2
enclosed by means of a plate Q¹ that is let into the face of said head and is secured
by means of two screws q and q¹ placed at its upper and lower side. A slot qu
near its lower end enables the eye p₁ of said take-up to pass outward. The slack
of the upper portion of the thread, caused by the downward movement of the needle-
bar, is taken up by a light spring R¹ which is secured upon the side of the covering 2
plate Q¹, and extending upward is provided at its upper end with a hook ¹ that
engages with said thread between the tension and said needle-bar, said spring being
so arranged as to cause its upper end to draw said thread rearward. The presser-
bar F corresponds in size and shape to the like features of the needle-bar E and is
contained in a groove d¹ in the rear side of the head D. Downward pressure is 3
given to said bar by means of a spring S¹ which is contained between a lug ŕ that
extends inward from the inner face, near the longitudinal centre of said bar and a
block T¹ which is placed at some distance above the same.
.11
The block T¹ is moved vertically by means of a rod U¹ which is swivelled within
the upper end of the head D and passes downward through said block; the spring S²,
and the lug f, and for some distance above and below said block, is provided with a
screw-thread which corresponds to a threaded opening in the latter. The block T
is prevented from revolving with the rod U₁ by means of a lug til which extends
rearward into a vertical groove 111 in the head D.
The construction described gives to the presser-bar E a direct downward pressure, *
which may be varied at will by turning the screw-rod U₁ for which purpose the
upper end of said rod is provided with a milled hed u¹¹.
11
The presser-bar E is raised to and locked in an elevated position by means of a
cam-lever V¹, which is pivoted within the head D and works within a notch f¹ that
is provided with flanges w' which embrace the edges of the presser-bar F, as seen in 4
Figs. 24 and 25. Upon the rear face of the presser-foot W! is provided a lug tes
provided with a horizontal threaded opening w that is but one-half outside
which extends through a corresponding opening f" in the presser-bar F, and is
of the rear-face of said presser-bar. Between the opening f" and the rear-face
insertion within the threaded opening will of the lug w11 of a screw X' which has a
of the presser-bar F is provided a half-round groove fill, which permits of the 5
pointed end, which end, when caused to project through said lug, bears upon the
rear-side of said presser-bar contiguous to said opening f, and operating
wedge draws the presser-foot firmly against the front side of said presser-bar. The
means employed for securing the presser-foot in position is simple, efficient, and 55
easily manipulated, and may also be employed for connecting other attachments to
or with the presser-bar.
as &

page_text: The shaft F and the lever V are each provided with axial bearings which as lost
motion is caused by wear, may be made close and as good as when new. Through
each of said parts passes a screw Y¹, Fig. 26, that at one end is provided with a
screw thread y, from whence, towards the head y¹, said screw is parallel, and plain
for a distance equal to the length of the part to be pivoted, and terminates in an
outwardly inclined shoulder yll, from whence to said head said screw is plain. One
end of the part P or V is made conical and fits into a corresponding recess of the
adjacent support, while within its opposite end the opening through which passes
the screw Y₁ is enlarged and made to conform to the shoulder y. The parts P
or V being now placed in position, with its conical end within the recess prepared
for it, the screw Y¹ is inserted and turned inward until the shoulder y bears
within its recess with sufficient firmness to prevent end motion of said pivoted part
and cause the principal wear to be upon said conical bearings. Between the head y
of the screw Y¹ and the part through which said screw passes is placed a washer
111 of soft metal, which has such thickness as to permit said screw to pass inward
the precise distance necessary before said head has a firm bearing. When the
pivoted part has become worn so as to allow of end motion, by removing said
washer and filing a little from the face of said washer said screw will be enabled to
pass further inward, and by bringing its conical shoulder y¹¹ nearer to the conical
bearing for the rear end of the pivoted part renders the latter as firm as before.
Having now described my Invention, and the manner in which the same may be
carried into practical effect, I wish to have it understood that I do not limit myself
to the exact construction of devices as herein before described, as these or some of
them may be varied within certain limits without departing from the peculiar nature
of the Invention, but what I do claim is,-
11
1st. As a means for operating the vibrating arm K, and in combination there-
with, the shaft M provided with the disk O and crank-pin o, the shaft P having
the radial arm p provided with the slot p¹, the sliding-block Q fitted within said
slot and over said crank pin, and the connecting bar R pivoted at its ends to or
upon the lower end of said vibrating arm K and the outer end of said slotted
arm p, said part being combined to operate in the manner and for the purposes
substantially as specified.
2d. As a means for operating the shuttle carrier T, and in combination with the
same the lever V pivoted at its upper end within the hollow boss B, the bar W
connected at its lower end with and forming part of the eccentric strap w, and
having its upper end pivoted to said lever in front of and below the pivotal bearing
of the same, the eccentric X secured upon and revolving with the shaft M, and the
bar Y pivoted upon and extending between the lower end of said lever and the rear
end of said carrier, said parts being combined to operate in the manner and for the
purposes substantially as shown.
3d. As a means for imparting longitudinal motion to the feed-bar Z, and in com-
bination therewith the eccentric X, the strap w, the bar W provided with the
longitudinal slot w¹, the pivoted block b', the bar B¹ having the angular arm b",
the pivoted bar C¹ engaging with a shoulder of said feed-bar, and provided with
the cam-recess c², which engages with a bearing D¹, said parts being combined to
operate in the manner and for the purposes substantially as set forth.
4th. The means employed for imparting vertical motion to the feed-bar Z, con-
sisting of the shaft H' journalled length wise of and below the base-plate A, provided
at its front end with a crank arm h, which extends beneath said feed-bar, and
0 having at its rear end a second crank arm h¹ that at its end engages with a cam
groove o¹, which is formed within the inner face of the plate or disc O, said parts
being combined to operate in the manner and for the purposes shown and
described.
5th. The means employed for regulating the longitudinal motion of the food-bar
5 Z, consisting of the bar E' provided at its inner end with a roller D', and made
longitudinally adjustable towards or from the cam recess c¹ of the bar C' by means

page_text: of the screw F', said parts being combined to operate in the manner and for the
purposes substantially as specified.
6th. As a means for giving to the tension-plate L¹ a yielding pressure against the
plate M¹ the flat spring O¹ contained within the head D, having its lower end
secured in position between the sections of said head, and its upper end forked, the 5
screw N¹ passing through said tension plate, and at its inner end in engagement
with the forked end of said spring, and the thumb-nut n¹ placed upon the outer
end of said screw, said parts being combined to operate in the manner and for the
purposes substantially as shown.
7th. As a means for taking up the slack of the thread the head D provided with
the thread eyes d¹ and d, the vibrating arm K having near its outer end the
stud /' and the plate P' pivoted at its upper end within or upon the upper rear
portion of said head, provided at its lower end with a thread eye p, and having a
longitudinal slot p¹, which extends downward and then rearward and downward,
and engages with said stud k¹, said parts being combined to operate in the manner
shown, so that the said thread eye p₁ is caused to move forward in a line parallel
with the length of the machine while said vibrating arm K is passing from the
centre of oscillation to the lower limit of its motion, and to move rearward as said
vibrating arm rises to its centre of oscillation, substantially as and for the purposes
set forth.
11
8th. The means employed for giving to the presser-bar F a downward yielding
pressure, consisting of the spiral spring S¹ resting upon the lug f of said bar, the
block T¹ placed at the upper end of said spring, and provided with a radial lug t
which engages with a vertical groove du which is formed in the head D, and the
threaded rod U¹ that passes downward through said head, said block T¹, and
said spring S¹, and lug f, said parts being combined to operate in the manner and
for the purpose substantially as specified.
9th. As a means for connecting the presser-foot W¹ to or with the presser- bar F,
and in combination therewith the interiorly threaded lug w¹ projecting rearward
from the former through the opening fi in said presser-bar, and the pointed
screw X¹, which passes through said lug and fits within a half-round groove fill in
said presser-bar, in the manner and for the purposes substantially as specified.
10th. The means employed for pivoting the shaft P, having in one end a conical
recess, and upon the opposite end a conical bearing, and for compensating for pivotal
wear of said shaft, consisting of the screw Y¹ provided at one end with a screw-
thread y, and near its head with an inclined shoulder y, and having beneath its
head y¹ a washer y111, substantially as and for the purpose set forth.
In witness whereof, I, the said James McAllister, have hereunto set my hand
and seal, this Sixth day of October, in the year of our Lord One thousand
eight hundred and seventy nine.
JAMES MCALLISTER. (L.S.)