An Improved Feed Chain for Sack Sewing Machines.
Year: 1890

page_text: Date of Application, 10th May, 1890
Complete Specification Left, 9th Feb., 1891-Accepted, 14th Mar., 1891
PROVISIONAL SPECIFICATION.
An Improved Feed Chain for Sack Sewing Machines.
We, JOHN TARBET, of 19, Bonnybank Road, Foreman Mechanic, and DAVID
JOHNSTONE MACDONALD, of 22, Nelson Place, Superintending Engineer, both of
Dundee, in the County of Forfur, N.B., do hereby declare the nature of this
invention to be as follows:―
The object of our invention is to draw forward the cloth towards the needle at a
uniform rate, and to make it move in a straight line parallel to the feed chain.
Our invention is specially applicable to overedge sewing machines used to sew
sacks.
The feed chains at present in use on overedge sewing machines are of three kinds.
In the first type, the upper surface of the links catches hold of the cloth to be
operated upon by means of a series of pointed teeth, the points and bases of which
are in the same plane, and which are of such a shape as to draw the cloth forward;
although offering little resistance to a lateral pull. The second type is somewhat
similar to the first, in that the points and bases of the teeth are in the same plane,
but they are cut so as to draw the cloth forward and at the same time resist a
lateral pull-due to the friction of the spiral needle and thread passing through the
cloth to a greater degree.
The third type has a series of spikes or hackles in the upper surface of its links,
the points of which are in the same plane and which are intended to protrude
through the cloth and draw it forward, at the same time offering a resistance to a
lateral pull. This form of chain draws forward the cloth uniformly and resists a
lateral pull, but the spikes are apt to get entangled in the material and thus damage
the cloth and the machine.
In our invention we draw forward the cloth at a uniform rate, resist a lateral
pull and avoid the possibility of entangling the chain in the material being
operated upon. In it, the teeth are formed to draw forward the cloth, and to resist a
lateral pull, by making the points of said teeth in different planes. We prefer to
make the points of the teeth to lie in the circumference of a circle-the teeth at the
centre being longer than those at each side and the distance between the said points,
as measured across the chain, unequal. As in the other chains, we use a spring
pressure bar which fits over the top of the chain, the cloth passing between said
cover and chain. The links of our improved chain may. be jointed or coupled
together in any approved manner.
Dated this 6th day of May 1890.
GEO. C. DOUGLAS & Co.,
Applicants' Agents.
COMPLETE SPECIFICATION.
An Improved Feed Chain for Sack Sewing Machines.
We, JOHN TARBET, of 19, Bonnybank Road, Foreman Mechanic, and DAVID
JOHNSTONE MACDONALD, of 22, Nelson Place, Superintending Engineer, both of
Dundee, in the County of Forfar, N.B., 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 :-
The object of our invention is to draw forward the cloth towards the needle at a
1

page_text: uniformn rate, and to make it move in a straight line parallel to the feed chain.
Our invention is specially applicable to overedge sewing machines need to sew
sacks.
The feed chains at present in use on overedge sewing machines are of three kinds.
In the first type, the upper surface of the links catches hold of the cloth to be
operated upon by means of a series of pointed teeth, the points and bases of which
are in the same plane, and which are of such a shape as to draw the cloth forward:
although offering little resistance to a lateral pull. The second type is somewhat
similar to the first, in that the points and bases of the teeth are in the same plane,
but they are ent so as to draw the cloth forward and at the same time resist. a
lateral pull due to the friction of the spiral needle and thread passing through the
cloth to a greater degree.
The third type has a series of spikes or hackles in the upper surface of its links,
the points of which are in the same plane and which are intended to protrude
through the cloth and draw it forward, at the same time offering a resistance to a
lateral pull. This form of chain draws forward the cloth uniformly and resists a
lateral pull, but the spikes are apt to get entangled in the material, and thus damage
the cloth and the machine.
In our invention we draw forward the cloth at a uniform rate, resist a lateral
pull, and avoid the possibility of entangling the chain in the material being operated
upon. In it, the teeth are formed to draw forward the cloth, and to resist a lateral
pull, by making the points of said teeth in different planes. We prefer to make the
points of the teeth to lie in the circumference of a circle-those teeth at the centre
being longer than those at each side and the distance between the said points, as
measured across the chain unequal. As in the other chains, we use a spring
pressure bar which fits over the top of the chain, the cloth passing between said
cover and chain. The links of our improved chain may be jointed or coupled
together in any approved manner.
The accompanying sheet of explanatory drawings illustrates the method of
carrying out our invention.
Figure 1. represents a side view of the chain in position on the machine. Figure 2.
a section at A. A. and Figures 3. 4. and J. a side view, un end view, and a plan
respectively of one link of the chain containing our improvements and drawn to a
larger scale.
In these drawings the same reference numerals are used to mark the same or like
parts wherever they are repeated.
6. are the links containing our improvements, 7. is the driving pulley and 8. are
guide pulleys of the machine. 9. is the spring pressure bar and 10. the textile
material.
Figures 3. 4. aud 5. more particularly show wherein our improvements consist.
The points of the series of teeth 11. all are on the same level, while the points
of the other series 12. are on a lower level the result being that as shewn in Figure 3.
the points of each series 11. and 12. are in different straight lines, while in Figure 4.
the four points 12. 11. 11. 12. are in the circumference of a circle, as shewn by the
dotted lines.
The action of the chain is as follows:-As illustrated by Figure 1. the chain is
supposed to be moving in the direction of the arrow taking the cloth along with it.
In Figure 2. the spring pressure bar which is formed to suit the teeth of the chain
is shown bearing upon the textile material 10. thus effectually keeping it from
moving in the lateral direction indicated by the arrow.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
In sack sewing machines the manufacture and use of the feed chain for drawing

page_text: forward the textile material and at the same time resisting the lateral pull,
substantially as hereinbefore described and illustrated in the accompanying
drawings.
1001
GEO. C. DOUGLAS & Co.,
Applicants' Agents.