IMPROVEMENTS IN CLOTH CLAMPS FOR BUTTON-HOLE SEWING MACHINES
Year: 1885

page_text: I, ALEXANDER ANDERSON, Manager of the Singer Manufacturing Company's
Works, Kilbowie, Dumbartonshire, do hereby declare the nature of my invention
for "IMPROVEMENTS IN CLOTH CLAMPS FOR BUTTON-HOLE SEWING MACHINES," (a
communication from the Singer Manufacturing Company of New York, in the
United States of America,) and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement :-
My invention relates to that class of cloth or fabric clamps adapted to open or
spread the button-hole after the fabric has been clamped, my object being to
improve the construction of these devices so that their action will be more positive
and reliable, and thus lessen their liability to break or get out of order, as well as
to add to their convenience.
In carrying my invention into effect I provide the base plate of the cloth clamp
with guides adapted to hold the lower plates or jaws of the clamp in place on said
base plate but permitting said jaws to slide transverely of said plate a limited
distance, the upper jaws of the clamp being mounted on the lower jaws so as to
slide therewith. The base plate is provided,with a recess in which is placed a
slide provided with inclined ribs working in inclined grooves in the bottoms of
the lower clamping jaws, said slide being connected by a link with an operating
lever. The backward or forward movements of the slide cause both sets of
clamping jaws to recede from or approach each other, these movements of Baid
jaws being positive in both directions and the jaws remaining at all times parallel
with each other so as to spread the button-hole evenly its entire length.
The upper clamping jaws are pivoted or hinged to blocks carried by the lower
jaws and are operated to clamp or release the work by an arm or lever attached to
a small shaft having a crank connected by a link to a cross bar engaging the arms
of said jawa, the latter being thus operated positively in both directions. The
operating levers for the spreading slide and the upper clamping jaws are preferably
so arranged that they will both be moved in the same direction in clamping the
goods and spreading the button hole, so that both of these results may be effected
by one and the same movement of the hand of the operator.

page_text: In the drawings, Figure 1 is a plan view of a button-hole cloth-clamp embodying
my invention, with the clamping jaws together, and Figure 2 is a similar view
with the jaws moved apart as in spreading the button hole. Figure 3 is a side
view with the parts in the same position as in Figure 2. Figure 4 is a front end
view. Figure 5 is a side view, partly in section, with the upper jaws raised, and
Figure 6 is a similar view with the upper jaws down as in clamping. Figure 7 is
a top view.of the base plate and spreading slide and Figure 8 is a bottom view of
the lower clamping plate. Figure 9 is a plan of a modified form of clamp showing
the lever which I provide for lifting the spring depressed guide pins, and Figure 10
is a sectional elevation of the same.
A indicates the base plate of the clamp and a and a' two sets of under-cut
parallel guides thereon, the former being removably attached to said plate.
B B are the lower clamping plates or jaws having at their ends lips b fitting
beneath similar overhanging lips a³ on the under-cut guides. The plates B are
provided on their undersides with inclined grooves 61. O is a spreading slide
movable in a recess a³ in the base plate A and having inclined ribs e fitting easily
in the grooves b₁ of the plates B. The slide C is connected by a link & with a
lever D pivoted to an arm or bracket e of the post E on the base plate, through
which post the guide pin e* of the clamp passes, said pin being normally depressed
by a spring e¹.
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F, F, are block rigidly secured to the plates B, and to the blocks F are hinged
plates G to which latter are rigidly secured the arms h of the upper clamping
jaws H, the arms h being preferably recessed into the plates G, as shown, and the
jaws H being pivoted to said arms, as is usual. I is a small shaft journalled in
the blocks F, and having a crank, i connected by a link or pitman J to a cross
bar K slotted at its ends for the free passage of the arms h. The arms h are of
spring metal, as is usual in clamps of this kind, and the depth of the slots k in the
ends of the cross bar K is preferably considerably greater vertically than the
thickness of said arms so that the stress of the latter in forcing the jaws H against
the fabric may be varied by regulating screws tapped in said cross-bar. L is an
arm or lever, attached to the shaft I, by which the latter may be operated to clamp
or release the work.
°
The operation of this device is as follows.-When the work is to be inserted the
upper clamping jaws will be raised, as in Figure 5, by lifting the lever L, and by
moving said lever forward and downward, in the direction indicated by arrow 1 in
Figure 3, the shaft I will be turned, and the crank i, link or pitman J, and cross-
bar K, moving with said shaft, will force, down the arms and their attached
jaws H to the clamping position indicated in Figure 6, when the crank i will be
just past the dead centre and its further rearward movement be prevented by the
contact of the link or pitman J with the post E, as shown in Figure 6, and thus,
owing to the position of said crank, the jaws H will be retained in the said
clamping position by the resistance of the spring arm h which yield to allow the
crank to pass the dead centre.
If the button-hole has not yet been cut this will next be done by the proper
cutter, but in working holes which have been cut in advance the hole can be
spread the instant the clamping lever has been depressed by moving the spreading
lever D forward in the direction indicated by arrow 2 in Figure 3, and this move-
ment of the said lever D can be effected by the same movement of the hand of the
operator by which the clamping movement of the lever L is accomplished, these
two. levers both turning on horizontal pivots and both moving forward, or in the
same direction, in clamping and spreading the button-hole. The forward move-
ment of the lever D forces the slide C backward, and the inclined ribs c on the
latter, working in the inclined groove 6 of the plates or lower clamping jaws B
move said jaws outwards or away, from each other and thus, effect the spreading of
the button hole, the outward movements of the said plates or jaws B and of the
upper jaws H which are mounted thereon and rigidly connected laterally therewith,

page_text: being uniform throughout, so that said jaws will remain parallel with each other
at all times and thus spread the button hole evenly its entire length.
When the button hole is finished the work will be released and the clamping
jaws again moved together, as in Figure 1, by turning the levers L and D in the
direction opposite to that indicated by the arrows in Figure 3, the upper clamping
jaws being lifted positively by the cross-bar K. and the inward movements of the
plates or jaws B being also effected positively by the rib and groove connection of
said plates and the slide C. By making all these movements positive I am enabled
to dispense with springs heretofore employed to effect reverse or return movement
in this class of devices, these springs being objectionable by reason of their liability
to break or to lose their force after considerable use.
It is obvious that the rib and groove connection of the plates B and slide C
might be reversed by forming the ribs on the former and the grooves in the latter,
or instead of these ribs other projections, as pins, with or without rollers, working
in inclined or diagonal slots, might be employed.
In Figures 9 and 10 which show the lifting lever arrangement, the post E has
an arm or bracket e, to which is pivoted the lifting lever M, and to the top of said
bracket is attached a spring e¹ the free end of which is in engagement with the
pin e, the said spring serving to depress the said pin, and the latter being preferably
provided with a flange e¹¹ or other projection near its top beneath which the top or
forward end of the lever M extends. The post E is provided at its top with a
notch in which the lifting end or toe of the lever M fits, said lever, when not in
use, being held in place between the bottom wall of said notch and the flange e¹¹.
A top pin e serves to limit the lifting movement of the lever M.
By depressing the near end of the lever M. the guide pin e' may be quickly and
easily lifted, thus obviating the inconvenience incident to the clamps heretofore in
use in which the guide pins are lifted by pulling upwards on their heads.
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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
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1. In a button-hole clamp the combination with the base plate and the upper
and lower clamping plates or jaws adapted to move laterally thereof, of a spreading
slide having rib and groove connections with the said lower plates or jaws,
substantially as set forth.
2. In a button-hole clamp the combination with the base plate, having parallel
guides, of two lower plates or clamping jaws adapted to slide laterally on said base
plate in said guides, two upper clamping jaws mounted on and rigidly connected
with said lower plates or jaws and a slide for moving the latter plates from or
towards each other, substantially as set forth.
3. In a button hole clamp the combination with the base plate and the upper
and lower clamping plates or jaws adapted to move laterally thereof, of a spreading
slide movable longitudinally of the said lower plates or jaws and having rib and
groove connections therewith, a spreading lever connected with said slide and a
clamping lever connected with the said upper jaws, both of said levers being
movable in the same direction in performing their respective functions, sub-
stantially as set forth.
4. The combination with the base plate, and the upper and lower clamping jaws
of a slotted cross-bar for operating the said upper jaws, a pitman or link and a
shaft having an arm or lever and a crank, whereby the said upper jaws may be
positively lifted and forced down, substantially as set forth.
5. The combination with the base plate and the lower plates or jaws of blocks
rigidly fixed thereto, plates hinged to said blocks, arms, carrying the upper clamping
jaws, rigidly attached to said plates, a shaft journalled in said blocks and having
an arm or lever and a crank, a cross-bar engaging the said arms of the clamping
jaws and a pitman or link connecting said cross-bar and crank, substantially as set
forth,
"
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page_text: 6. In a button-hole clamp the combination with the base plates the upper and
lower clamping plates or jaws, the spring arms by which the upper jaws are carried
and the cross bar engaging said arms, of a shaft having an arm or lever and a
crank, a pitinan or link and a post with which the latter is in contact when the
upper jaws are in clamping position and the said crank is past the dead centre,
substantially as set forth.
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7. The combination with the base plate and the lower and upper clamping jaws,
of a slotted cross-bar through which the spring arms of the latter loosely pass,
regulating screws on said cross bar for varying the stress of said arms, and devices
for raising and lowering said cross bar, substantially as set forth.
8. In a button-hole clamp the combination with the base plate and the lower
clamping plates or jaws mounted loosely thereon and provided with inclined
grooves or slots, of a spreading slide having projections fitting in said grooves or
slots, substantially, as set forth.
9. In a button-bole clamp the combination with the base plate of a hollow post
having a notch at its top and an arm or bracket, a guide pin fitting in said post
and having a flange or projection, a lifting lever, pivoted to said bracket and
extending into said notch beneath said flange or projection, and a spring for
depressing said pin, substantially as set forth.