IMPROVEMENTS IN SEWING MACHINES
Year: 1858

page_text: This Invention received
application for Letters Patent was not given within the time prescribed
by the Act.)
PROVISIONAL SPECIFICATION left by Richard Archibald Brooman at
the Office of the Commissioners of Patents, with his Petition, on the
21st August 1858. A communication.
I, RICHARD ARCHIBALD BROOMAN, of 166, Fleet Street, in the City of
London, E.C., Editor of the Mechanic's Magazine, and Patent Agent, do
liereby declare the nature of the said Invention for "IMPROVEMENTS IN SEWING
MACHINES," (communicated to me by a foreigner residing abroad,) to be as
follows:-
These improvements relate to the feed of material to be sewn in a sewing
machine, and consist in a means of causing the cloth to progress by mechanism
acting so as to grasp the cloth between the surfaces, and give the feed without
the aid of spring pressure. The means by which the feeding foot is made to
operate with a positive force without spring pressure consists of a slide bar so
connected with the foot, that while imparting a positive motion at each feed
action to bring the said foot upon the cloth, it yet provides for self-adjustment
to meet the requirements of different thicknesses of materials as well as for
going over seams. Another feature operating in connection with the feeding
foot is a means for obviating the tendency of one surface of the cloth to slip
upon the other piece. This is accomplished by making a section of the table
directly under the place where the foot acts capable of sliding back and forth
in the line of the feed. Both surfaces thus move along together, thereby
causing both pieces of cloth to travel alike.

page_text: The feeding foot is seen at a, and is a bar curved as shown, having a wedge-
shaped end, where it acts upon the cloth. It is placed at the extremity or
head of the bracket or arm A overhanging the table, so as to stand nearly
vertical, and at one side of the needle bar b. The curve brings the wedge a¹
underneath the head of the bracket, and in close proximity to where the
needle plays, as seen in Figures 2 and 3. The feed foot has two motions; one
motion is vibratory in the line of the feed, while the other motion is recipro-
catory and perpendicular to the table. In the shank a there is a slot cut, as
seen in the dotted line a¹ of Figure 2, through which there is a fixed pin c;
this is in the end plate of the bracket A, and by it the shank becomes secured
to the bracket. The shank plays along the pin by its slot, and is thus able to
perform the up and down motions as well as the vibratory one in the line of
feed. The distance upward the motion of a is allowed to extend is regulated
by the position of the pin c, because that pin acts as a stop on being struck by
the bottom of the slot. Movement is given to the feeding foot by two pieces
of mechanism, which act independently of each other; thus the up and down
motion is produced by one piece, and the feed motion by the other piece of
mechanism. The most important is that which raises and lowers the presser
foot, because, as this is done by positive force, the principle of self-adaptation
to act on various thicknesses of materials without the aid of spring pressure is
involved in it. The distance of travel of the piece which raises and lowers the
feed foot is always the same. The foot. is raised by means of a slipping bar
seen at d, being a flat plate, part of which is straight, viz. that portion which
presses against the side of a, and having a crook to set off the upper portion
as at . In the flat part d there is a slot cut, as shown in Figures 2 and 3.
Through this slot and also through the side of a, there is a small screw bolt e,
having a milled head on one end, and a like milled nut on the other; by this
screw, therefore, the bar d is held up against a. The pressure of d upon a is
regulated to such a degree as is necessary to give the required friction for
raising the feed foot, and for bringing it down with sufficient force to grip the
materials which are being sewn. It will now be seen that the adjustment for
degrees of thickness lies in the operation of the two slots, viz., that in d, and
that in a, for as d always travels the same distance in its motions, if a is
arrested either in going up or down before d has reached the end of its stroke,
d must slip along the surface of a, the slot permitting of such movement.
The operating of d is by means of crank and cam work of ordinary character.
f is a bell crank, shaped as shown, to one of which the slipping piece d is
fixed, and this end also receives the action of the cam which gives the down
motion. The upward motion is produced by a cam striking the other end f"

page_text: of the bell crank. In forcing down d the cam does not strike directly upon
the arm f, but acts upon a curved piece projecting out from the said arm, and
as seen at f of Figures 1 and 3. The cams are placed upon the end of the
revolving shaft g. That which operates the end f" is a bevelled-edged piece
fixed to the inner side of the crank arm, as shown at h, Figures 1, 3, and 4;
in Figure 4 it is shown as in the act of striking the said arm. The other cam
is a curved piece prolonged from the end of the crank which drives, the needle
bar, as shown at h. This cam acts not only on the arm f, but also produces
the motion for giving the feed. In forcing down d, this cam strikes the
curved piece first at or near the place where that joins, the toe f¹ giving the
down thrust and maintaining the pressure upon the feeding foot for a con-
siderable portion of a revolution, i.e. until the needle has been completely
withdrawn above the table. This it does by means of the great amount of
the surface over which the cam acts, and which extends the whole length of
f. By keeping the foot down during this portion of the revolution of the
shaft, it acts as a cloth stripper for the needle. When the cam h¹ has got
clear of the toe f, the feed takes place, and although at that time there is no
pressure maintained upon the feeding foot, yet it will not slip by without
carrying the cloth with it. This arises from the position the wedge has with
respect to the axis point or pin upon which it vibrates. It will be seen that a¹
is not placed directly beneath that pin a", but stands at one side of it, as seen
in Figures 2 and 3.
In moving from the position as in the first-named Figure to that of the
last, the course of the wedge, if unobstructed, would be to describe an arc, the
curve, sinking beneath the surface of the table; but as the foot follows the
plane of the table, the shank a is compelled to rise, and it slips therefore along
the piece d, the upward motion being, all the while resisted by the friction of
the two surfaces in contact, so that although the direct action of the cam h' is
taken off, the gripping action still continues until the end of the feed. The.
feeding motion, i. e., that motion which gives the onward direction to the
cloth, is produced by the cam h¹, striking the tail of the cranked lever shown.
at the head of the bracket A. One end of this, lever at i in the several
Figures acts upon that end of the bar a which is situated above the axis pin c..
The other end at ¹ is acted upon by the cam' h¹. The point of the screw in i
strikes a, and the length of stitch is regulated by the distance; this is screwed
in or out in a manner well known and common to sewing machinery. The
part which causes both surfaces of cloth to move together is the sliding plate,
or section of the table as heretofore mentioned. This plate is seen at o, and
is a sliding piece laid in a recess of the table, so as to lie flush with its surface

page_text: and to be guided at those sides which lie parallel to the line of feed. There
is a cross cut o¹ in the said plate, which cut is intended to receive the wedge
part of the feed piece, and it is by this that the plate is carried along by the
said feed piece, when moving in that part of its motion which gives the feed
to the cloth. The return of the plate back after the foot is raised, is effected
by a spring acting beneath. When feeding cloth, the action of the feed foot
is to force the materials down into the cross cut, and then a firm grip is given
to both pieces, and therefore, by the plates moving at the same time as the
feed foot and along with it, all the cloth is carried in a body also. The
moment that the foot rises for a new hold, the plate, being no longer held, flies
back, slipping past the cloth at that time.
The other parts of the machine being as usual, it is needless to describe
them. The operation will be as follows:-The needle being threaded and
raised above the table, raise the feed foot also, and slip the cloth under it,
revolve the shaft g, and the sewing will then go on.
The needle descending
passes through the cloth, and the feed foot will then come down and press
upon the cloth at the spot which is directly over the cut o¹ in the plate o. The
cam is at that time acting upon f, and the foot will press the cloth into
the said cut. The travel of d is such as to bring the foot down hard upon the
plate when there are no materials to be sewn upon it, consequently the wedge
will be stopped sooner or later in the downward movement, according to the
degree of thickness in the cloth, and therefore according to such thickness will
be the extent of the slipping movement of the piece d. The needle now
rising, the cam ' strikes i, and gives the feed; while the cam h¹ is still on i,
the other cam h has arrived so as to strike the arm f¹ of the bell crank, and
the slipping piece d is accordingly raised; as soon as the foot has been lifted to
a proper height, the bottom of the slot a¹¹ will have arrived at the pin c, and
the further motion of the foot will be arrested, though the slipping piece will
still go on to the end of its stitch. In this way the raising and bringing down of
the feed foot will always be caused to accommodate itself to all thicknesses of
material it may be required to sew, as well as to different degrees of thickness
in the same material. If the goods are thin, less pressure of the foot will
answer to feed, consequently the nut e may be slackened, and the friction of d
against a lessened; and it may also be tightened for harsh and heavy goods
according to the necessities of the case.