RESERVE and other similar Wrought Metal Work.
Year: 1888

page_text: Date of Application, 2nd Oct., 1888
Specification Accepted, 16th Nov., 1888
RESERVE
and other similar Wrought Metal Work.
I, LEMUEL COBURN, manufacturer of Holyoke, County of Hampden, State of
Massachusetts, United States of America 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 relates to machines for bending metal in parallel longitudinal folds
and particularly applicable for use in the manufacture of trolley tracks of a peculiar
form, but as will appear from the description hereinafter given it embraces certain
constructions and contrivances common to and applicable in machines for bending
metal for other purposes; and the invention consists in the constructions and com-
binations of parts as will hereinafter fully appear and be set forth in the claims.
In the accompanying sheet of drawings, figure 1, represents in side elevation and
partial central longitudinal vertical section a machine for bending flat strips of sheet
metal into the form desired and suitable for trolley tracks, and figure 2 is a plan
view of the lower portion thereof which is below the plane indicated by line v v
figure 1. Figure 3, represents an enlarged detail view in horizontal section on
line, w, w, Figure 1. Figure 4, represents in perspective and enlarged, a section of
a sheet metal trolley track such as may be formed under the operation of the present
improved sheet metal bending machine. Figures 5, 6 and 7, are enlarged vertical
cross-sectional views of the die portions of the machine respectively on lines, x, x, y, y,
and 2, 2, of Figures 1 and 2, there also being indicated thereupon or in relation
thereto the cross-section of a strip of sheet metal in the various phases thereof which
it possesses or is inade to possess under the action of the various parts of the machine.
Figure 8, is an enlarged view in perspective of a portion of the length of the draft or
hook rod to be hereinafter referred to, and Figure 9, is a perspective view of a strip
or blank of sheet metal of a form suitable for the production of the trolley track.
The present machine comprises three sets of die apparatus A, B and C, each
comprising the lower portion within or upon which the sheet metal strip is disposed,

page_text: and the upper portion forming, or attached to a vertically reciprocating plunger, and
the several die parts are ranged and aligned longitudinally, as shown.
As to the die, A, see Figure 5, the purpose of which is to convert the sheet metal
strip from the flat form shown in Figure 9, into the U form indicated by dotted lines,
Figure 5, and the black cross-section, Figure 6, the lower or female portion, a, thereof
consists of a longitudinal metal trough of substantially U-shape in cross-section, with
its opposite walls for a portion of its height vertical, as shown and thence preferably
outwardly flaring as seen at, 4, and at the upper edge of each flaring side wall, hori-
zontal wings or shelves, c, may be provided; and the upper or male plunger portion
of this die is transversely of rectangular form, as shown.
The die B, see Figure 6, which is for converting the U or trough formed strip
into the form of a tube with transversely rectangular walls, as indicated by dotted
lines in said Figure, and the black cross-section Figure 7, as to its lower portion
consists of a longitudinal trough shaped body d, having horizontal bottom, and
vertical side walls e, with converging upper edges, f, within which is disposed a
parallel.core or wrapping bar, g: and the plunger portion, h, of said die B, is on
its under side formed with a horizontal central portion i, and downwardly and
outwardly diverging extensions, j, as shown, said horizontal portion, being of a
width about equal to the distance between the side walls of the U strip of metal
which is to surround the core bar g, and said flaring extensions, j are formed to lie,
when said plunger die is down, outside of the converging and inclined edges f, of
the lower trough body of the die.
rib
And the die, C, see Figure 7, which is for converting the rectangular tubular
strip as seen in the black cross-section Figure 7, to the form indicated in said
Figure by dotted lines, and as seen in Figure 4, as to its lower portion, o, consists
of a substantially rectangular trough shaped body with the upper inner edges k, of
its side walls curved inwardly as shown, within which is disposed a parallel core bar m,
of similar shape and size to the said core bar g, of the die B, but having in its upper
side a longitudinally extending depression or recess 1, and the plunger portion n
of said die C, is provided with a downwardly extending longitudinally arranged
p, exteriorly corresponding to the walls of the depression 4, in said core bar m.
The longitudinally aligned lower die bodies a, d, o, have in their bottom surfaces a
groove q, extending continuously therethrough and within which is placed a draft
rod D, adapted for a back and forth end wise play therein, said draft rod at its rear
end being provided with a rigid hook or dog r, and intermediate of its length it is
provided with pivoted dogs, s, s, having bearings within recesses, t, of the draft
bar, said pivoted dogs being weighted at their rear ends so that normally their
forward ends or noses u, stand above the upper side of said draft bar, and said dogs
are so adjusted on the draft bar that when the bar is in its normal position as seen in
Figures 1 and 2, the said dogs, 1, 3, 8, will stand in positions back of and against the
rear ends of the central bottom portions of the sheet metal strips when in their
respective places in the dies A B and C, as occurs in the operation of the present
machine; and said draft rod, D, at its forward end is provided with a cross-head 10,
and a ring eye 11, and to the said cross head one end of a rope 12, is attached which
passes rearwardly around a sheave 13, thence forward to and around a drum 14, and
rearward to an engagement with said ring eye 11, of the draft bar, as shown in
figure 1.
The bottom faces of the core bars, g, m are longitudinally recessed as at 15, to
permit the passage of the dogs, s, s, in the forward movement of the draft rod, it
being understood that in the return movement of said draft rod, said dogs are
depressed below the upper surface of the draft rod when passing under strips of metal
in the trough bodies, d, o through which they travel.
The side walls, 16, 17, of the lower trough bodies of the dies, B C, are formed of
wedge shape, or tapering in their length as seen in Figure 2, and said side walls
are intended to be drawn out a short distance, thereby widening the spaces between
said side walls and the core bars, releasing the bind upon the metal formed thereat ;
and the core bar, m, of the die; C, is made in two parts, an upper part, 18, and

page_text: lower part 19, each tapering as to vertical thickness, as shown in Figure 1, so that
when the upper portion 18, is drawn endwise forward, the height of the core bar, m,
is decreased, permitting a release from vertical bind of said bar upon the sheet metal
strip folded thereabout as shown.
The lower portion, 19, of said core bar, m, is jointed to the core bar g, in any
suitable manner, for instance "halved together" therewith as seen at, 20, Figuro 1,
and said wedged shaped side walls, 16, 17, are also jointed to move in unison; and
for convenient end wise projection of said tapering portions, 16 and 17, and 18, of the
dies, levers, 21 and 22, are fulcrumed in suitable fixed bearings, 23 and 24, of one
of the uprights, E, of the machine, the said lever, 21, by its lower slotted end
engaging a pin of the wedge wall, 17, and the lever, 2, by its lower slotted end
engaging a pin of the movable tapering part, 18, of core bar, m.
The said core bar, g at its rear end is suspended a slight distance above the bottom
of the lower trough body of dic, B, by the engagement therewith of a vertical
bolt 25, projecting upwardly and loosely through an aperture, 26 of a horizontal
web, 27, of the branched base of one of the uprights, E, said bolt being surrounded
between its head and said web by a stiff spiral spring, 29, and the vertical position of
said suspended ond of the core bar, 9, is adjusted by the interposition of the
washers, 28, about said bolt between the upper side of said bar, g, and the lower side
of the web, 27.
The under side of the male plunger of die, A, is provided at its under face near
each end, with vertical downwardly tapering pins, 30, in central longitudinal align-
ment which are for the purpose of entering the centrally aligned holes, 31, in tho
blank, G, of sheet metal to be bent for maintaining it contrally in the die for a uniform
and symetrical bending, and the draft bar D, has holes, 32, to permit the entrance
therein of said centering pins, 30.
As will be particularly seen on reference to Figures 1 and 3, each plunger die
is formed with a vertical groove 33, at its ends into which a tongue, 34, of a
V-edged bearing block, F, enters, the said V-shaped bearing blocks playing vertically
in corresponding V-shaped grooves, 35, of the standards, E. The tongue, 34, of
each V bearing block is provided with horizontally extending slots, 36, through which
bolts, 37, extend as also through the walls of the plunger body at each side of
the groove 33, said bolts being headed and provided with nuts for securing said
blocks in place. The said blocks have vertical walls or shoulder 47, extending laterally
beyond the faces of the tongues, 34 and between said shoulders, 47, and the inclined
ends, 38, of the plunger bodies wedges are driven which serve to force said blocks
to a close bearing at all times, and said wedges 39 are to be retained in place by
the overlying nuts, washers, or heads, 40, of bolts, 41, which pass through the bodies
of the wedge blocks, as shown.
The plungers are to be raised and held, and then lowered or allowed to descend in
any desired or approved manner, and as shown, the plungers are supported by ropes
or chains 42, from drums carried on an overhanging shaft, 43. Said plungers are
intended to be raised under the rotation of said shaft, and when at the proper height
held by dogs, 44, which are arranged on an oscilating shaft, 45, to which a spring, 46,
suitably applied thereto exerts a force to swing the said dogs into the vertical plane
of travel of the plungers to support them. On an oscillation of the dog-carrying
shaft, by the lever or crank 51, said supports are removed and the plungers are
allowed to descend under their own weight.
The operation of the machine herein described is as follows:
A blank sheet of metal, as G, is first placed lengthwise on the shelves, c, of the
lower portion of the die, A, then the plunger is allowed to drop forming the strip of
metal into the U shape. Then on the raising of the plunger, and projecting the draft
rod, D, endwise, as described, by the engagement of the rear hook, r. with the end of
the bottom of the U formed strip, the latter is carried horizontally endwise and made
to telescope the core bar, g, of die, B, then the draft rod is returned to place. Then
on the descent of the plunger , of said die, B, the said U strip is converted into
the form of a transversely rectangular tube. Then on withdrawing the side wedge

page_text: walls, 16 and 17, and projecting the draft rod forward, by its intermediate dog, s, the
said tubular formed strip is carried horizontally end wise and made to telescope the
core bar m. The said wedge walls are then returned to their closed positions and on
the descent of the plunger of die, C, the meeting edges of the strip are turned
inwardly and parallel with the side walls, as seen in Figure 4. Then on sliding the
wedge side walls and also the upper inclined or tapering part, 18, of core bar, m,
and drawing out the draft rod, D, said completed trolley track strip is by the outer
hook, s, carried out of the die, C. And in practice the plungers are all intended to
be moved in consonance with each other there being a sheet of metal to be bent as
described, placed on or in the lower portion of each of the dies, A, B, C, as plain.
Other means for making the side walls, 16 and 17, adjustable, than by forming
them with outer inclined sides as described, may be substituted as equivalents thereof,
as for instance, by having said separable side walls supported on and carried by screws
which are suitably supported in threaded bearings and to be operated by worm gears
carried by a common shaft.
The formation of the lower portion a, of the die, A, with the upper outwardly
flaring walls, b as shown, is most advantageous as it ensures a gradual bending of the
flat sheet of metal at the time of the impact of the plunger, obviating the liability of
any shearing action or breaking of the metal at the lines of bend, and assuring, even
in the bending of inferior sheet metal, most satisfactory and practical results.
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 sheet metal bending machine the combination with a longitudinal femalo
die, a, having horizontal bottom and vertical side walls terminating in upwardly
flaring walls, b, b, of a longitudinally arranged male plunger die substantially of
rectangular shape in cross-section suitably guided for a play into and away from said
lower die, substantially as and for the purpose described.
2. In a sheet metal bending machine the combination with a longitudinal trough
formed die having its bottom provided with centrally aligned apertures, of a corre-
sponding longitudinally arranged male plunger die provided with centrally aligned
pins, 30, and suitably guided for a play into and away from said trough formed die,
substantially as and for the purpose described.
3. In a sheet metal bending machine the combination with a female die, a, having
a horizontal bottom provided with aligned apertures, and vertical side walls termi-
nating in upwardly flaring walls, b, b, of a longitudinally arranged male plunger die
substantially of rectangular shape in cross-section, provided with centrally aligned
pins, 30, and suitably guided for a play into and away from said lower die, substantially
as and for the purpose described.
4. In a metal bending machine the combination with a longitudinally ranging
female die of suitable transverse contour, having a longitudinal groove or way, 9, and
a correspondingly formed male plunger die, of a slide or draft rod playing in said
groove and provided at its rear end with a dog or hook, r, substantially as and for
the purpose described.
5. In a metal bending machine the combination with a longitudinal female die of
suitable transverse contour having a longitudinal groove or way, 1, and a corre-
spondingly formed male plunger die, of a slide or draft rod playing in said groove and
provided at its rear end with a dog or hook, r, and a flexible connection by one end
attached to the forward end of said draft rod, thence passing to the rearward of the
said forward end around a suitable guide, thence forward to and around a rotatable
drum, and thence rearwardly to an engagement with said draft rod, substantially as
and for the purpose described.
6. In a metal bending machine the combination with the die, A, comprising the
lower longitudinal trough-part, a having horizontal bottom, and vertical side walls
terminating in the upwardly flaring walls, b, b, and the longitudinally ranging male
plunger die, of the die comprising the lower longitudinally arranged trough-part, d,

page_text: the longitudinal core bar of rectangular cross-section, within said trough-part, d, and
the plunger, h, having horizontal bottom i, with downwardly flaring wings, j, sub-
stantially as and for the purpose described.
7. In a metal bending machine the combination with the dic, A, comprising the
lower longitudinal trough-part, a having horizontal bottom and vertical side walls
terminating in the upwardly flaring walls, b, b, and the horizontally ranging male
plunger die, of the die, B, comprising the lower longitudinally arranged trough-
part, d, having horizontal bottom, and vertical side walls, one of which is laterally
adjustable, the longitudinal core bar of rectangular cross-section, supported within
said trough-part, d, and the plunger h, having horizontal bottom, i and downwardly
flaring wings,, substantially as and for the purpose described.
8. In a metal bending machine the combination with a female die of suitable cross-
sectional contour provided within one wall with a longitudinal groove or way, and a
plunger die of corresponding cross-section, and one or more sets of dies comprising
lower longitudinally arranged female portions of suitable cross-sectional contour pro-
vided within one wall with a longitudinal groove or way in continuation of said first
mentioned groove, and each provided with longitudinal core bar of suitable cross-
sectional contour, and suitably formed plunger dies, of a draft bar, D, arranged for
a slide in said continuous groove or way, provided with suitably arranged abutments,
for the purpose described.
9. In a metal bending machine, a trough and plunger die and one or more dies
comprising lower longitudinally arranged trough portions of suitable cross-sectional
contour, and one or more of said trough portions provided with a separable side wall
of wedge shape, suitably guided for a lengthwise movement, and the lever, 21,
engaging said wedge shaped side wall, combined with a longitudinal core bar of
suitable cross-sectional contour, substantially as and for the purpose described.
10. In a metal bending machine the combination with the trough and plunger
die, A, and a stationary standard or bracket, 27, provided with an aperture, 26, of
the die, B, comprising the longitudinally arranged trough body, the core har 9: and
plunger, the headed bolt, 25, passing through said aperture, 26, and connected to
the end of said core bar and the spiral spring 29, and washers 28, substantially as and
for the purpose. described.
11. In combination with the trough and plunger die, A, and the dic, B, comprising
the lower longitudinally arranged trough body, d, having the movable inclined side
wall, 16 core bar, g, and plunger h, of the die, C, comprising the lower longitudinally
arranged trough body having movable side wall, 17, jointed to said movable side
wall, 16, core bar, m, consisting of the lower portion, 19 having its upper face
inclined, and the upper portion, 18, having its lower face inclined, and having the
longitudinal depression, l, and the levers, 21, and 22, the former engaging said
inclined side wall, 17 and the latter engaging said upper core bar portion, 18,
substantially as and for the purpose described.
12. In a metal bending machine the combination with uprights, E, having vertical
slide ways, 35, therein, of a plunger die body having inclined ends, 38, and vertical
grooves, 33, thereat, the bearing blocks, F, having the shoulders, 47, and tongues, 34,
provided with the horizontally extending slots, 36, the headed bolts, 37, and the
wedges, 39, substantially as and for the purpose described.
13. In a metal bending machine the combination with uprights, E, having vertical
slide ways, 35, therein of a plunger die body having inclined ends, 38, and vertical
grooves, 33, thereat, the bearing blocks, F, provided with the headed bolts, 41, and
having the shoulders, 47, and tongues, 34, provided with the horizontally extending
slots, 36, the headed bolts 37, and the wedges, 39, substantially as and for the purpose
described.
14. In a metal bending machine the combination with suitable uprights, E, having
vertical slide ways therein and one or more plunger dies having bearings in said
vertical ways, of a longitudinally arranged, spring actuated rocker shaft, 45, provided
with fixed dogs adapted normally to lie in the vertical plane of movement of said

page_text: plunger dies, and said shaft being provided with a means for securing its rock
substantially as and for the purpose described.
15. In a metal bending machine, in combination, the frame or uprights, E, and the
die, A, comprising the lower trough portion, a, having horizontal bottom, and vertical
side walls terminating in the upwardly flaring extensions bb, and male plunger die of
substantially rectangular cross-section having the pins, 30, the die B, comprising
trough body d, having horizontal bottom and vertical side walls terminating in
inwardly inclining portions, f, one of which side walls is laterally movable the
transversely rectangular core bar g, supported within said trough body, d, and the
plunger die, h, having lower horizontal face i, and downwardly flaring wings, j, j, and
the die, C, comprising the lower trough body, o, having horizontal bottom, and
vertical side walls one of which is laterally movable, the core bar, m comprising lower
tapering portion, 19, jointed to said core bar, g, and the upper tapering portion, 18,
provided with the longitudinal depression, and the male plunger die n, having the
rib p, the said core bar portions, y, 19, being provided on their under sides with
the longitudinal way, 15, and the said horizontal bottoms of said lower trough
portions, a, d, o, having the longitudinal way, 9, the draft rod, D, adapted to slide in
said way, 7, having the aligned holes, 32, the rear hook, r, and the recesses t, t, within
which are pivoted the counter weighted dogs, ss, the overhanging drum shaft 43, and
the rope or chain supports between the drums and the plunger dies, substantially as
and for the purpose described.
16. The process of making a tube of substantially rectangular form in cross-section
having a longitudinal slot in one of its sides, the edges of which are bent inwardly,
which consists in first imparting to a sheet of metal a substantially U form in cross-
section, secondly bending the edges thereof at right angles to the sides, and thirdly
again turning portions of said edges inward to form said slot, substantially as set
forth.