The material in the hopper is fed to a con-
veyor by the vibration of the reciprocating
slider. The pulsating force of the slider is trans-
mitted through the rubber wedge and on to the
actuating rod. The amplitude of this force can
be varied by moving the wedge up or down.
This is done automatically by making the con-
veyor pivot around a central point. As the con-
veyor becomes overloaded, it pivots clockwise
to raise the wedge, which reduces the ampli-
tude of the force and slows the feed rate of the
material.
Further adjustments in feed rate can be
made by shifting the adjustable weight or by
changing the speed of the conveyor belt.
55
Workpieces of varying heights are placed on this slowly rotating cross-
platform. Bars 1, 2, and 3 have been set at decreasing heights beginning with
the highest bar (bar 1), down to the lowest bar (bar 3). The workpiece is
therefore knocked off the platform at either station 1, 2, or 3, depending on
its height.
WEIGHT-REGULATING ARRANGEMENTS
The loose material falls down the hopper
and is fed to the right by the conveyor system
which can pivot about the center point. The
frame of the conveyor system also actuates the
hopper gate so that if the amount of material
on the belt exceeds the required amount, the
conveyor pivots clockwise and closes the gate.
The position of the counterweight on a frame
determines the feed rate of the system.
The indexing table automatically stops at
the feed station. As the material drops into the
container, its weight pivots the screen upward
to cut off the light beam to the photocell relay.
This in turn shuts the feed gate. The reactua-
tion of the indexing table can be automatic
after a time delay or by the cutoff response of
the electric eye.
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By pressing down on the
foot pedal of this mechanism,
the top knife and the clamp
will be moved downward.
However, when the clamp
presses on the material, both it
and link
EDO will be unable to
move further. Link
AC will
now begin to pivot around
point
B, drawing the lower
knife up to begin the cutting
action.
CUTTING MECHANISMS
These 3 four-bar cutters provide
a stable, strong, cutting action by
coupling two sets of links to chain
four-bar arrangements.
The cutting edges of the knives in the four mechanisms move
parallel to each other, and they also remain vertical at all times to
cut the material while it is in motion. The two cranks are rotated
with constant velocity by a 1 to 1 gear system (not shown), which
also feeds the material through the mechanism.
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57
The material is cut while in motion by the reciprocating
action of the horizontal bar. As the bar with the bottom knife
moves to the right, the top knife will arc downward to per-
form the cutting operation.
The top knife in this arrangement remains parallel to the
bottom knife at all times during cutting to provide a true
scissor-like action, but friction in the sliding member can
limit the cutting force.
Slicing motion is obtained from the synchronized effort of
two eccentric disks. The two looped rings actuated by the
disks are welded together. In the position shown, the bottom
eccentric disk provides the horizontal cutting movement, and
the top disk provides the up-and-down force necessary for the
cutting action.
This four-bar linkage
with an extended coupler
can cut a web on the run
at high speeds. The four-
bar linkage shown is
dimensioned to give the
knife a velocity during
the cutting operation that
is equal to the linear
velocity of the web.
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58
FLIPPING MECHANISMS
This mechanism can turn over a flat piece by driving two
four-bar linkages from one double crank. The two flippers are
actually extensions of the fourth members of the four-bar link-
ages. Link proportions are selected so that both flippers rise up
at the same time to meet a line slightly off the vertical to trans-
fer the piece from one flipper to the other by the momentum of
the piece.
This is a four-bar linkage
(links
a, b, c, d ) in which the part
to be turned over is coupler
c of
the linkage. For the proportions
shown, the 180º rotation of link
c
is accomplished during the 90º
rotation of the input link.
VIBRATING MECHANISM
As the input crank rotates, the
slotted link, which is fastened to the
frame with an intermediate link,
oscillates to vibrate the output table
up and down.
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SEVEN BASIC PARTS SELECTORS
A reciprocating feed for spheres or short
cyclinders is one of the simplest feed
mehanisms. Either the hopper or the tube
reciprocates. The hopper must be kept
topped-up with parts unless the tube can be
adjusted to the parts level.
A centerboard selector is similar to reciprocat-
ing feed. The centerboard top can be milled to
various section shapes to pick up moderately
complex parts. I works best, however, with
cylinders that are too long to be led with the
reciprocating hopper. The feed can be contin-
uos or as required.
A rotary screw-feed handles
screws, headed pings, shouldered
shafts, and similar parts in most
hopper feeds, random selection of
chance-oriented parts calls for
additional machinery if the parts
must be fed in only one specific
position. Here, however, all screws
are fed in the same orientation)
except for slot position) without
separate machinery.
Rotary centerblades catch small U-
shaped parts effectively if their legs are not
too long. The parts must also be resilient
enough to resist permanent set from dis-
placement forces as the blades cut
through a pile of parts. The feed is usual
continuous.
A paddle wheel is effective for feeding disk-
shaped parts if they are stable enough. Thin,
weak parts would bend and jam. Avoid these
designs, if possible—Especially if automatic
assembly methods will be employed.
A long-cylinder feeder is a variation of the
first two hoppers. If the cylinders have simi-
lar ends, the parts can be fed without
proposition, thus assisting automatic
assembly. A cylinder with differently shaped
ends requires extra machinery to orientated
the part before it can be assembled.
A barrel hopper is useful if parts lend to become entangled. The parts drop
free of the rotating-barrel sides. By chance selection, some of them fall onto the
vibrating rack and are fed out of the barrel. The parts should be stiff enough to
resist excessive bending because the tumbling action can subject them to rela-
tively severe loads. The tumbling can help to remove sharp burrs.
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ELEVEN PARTS-HANDLING MECHANISMS
60
Gravity feed for rods. Single rods of a given
length are transferred from the hopper to the
lower guide cylinder by means of an intermit-
tently rotating disk with a notched circumfer-
ence. The guide cylinder, moved by a lever,
delivers the rod when the outlet moves free of
the regulating plate.
Feeding electronic components.
Capacitors, for example, can be delivered by
a pair of intermittently rotating gearlike disks
with notched circumferences. Then a pick-up
arm lifts the capacitor and it is carried to the
required position by the action of a cam and
follower.
Feeding headed rivets. Headed rivets, cor-
rectly oriented, are supplied from a parts-
feeder in a given direction. They are dropped,
one by one, by the relative movement of a
pair of slide shutters. Then the rivet falls
through a guide cylinder to a clamp. Clamp
pairs drop two rivets into corresponding holes.
Label feed. Labels are taken out of the
hopper by a carrying arm with a vacuum
unit to hold the label. The label is then
placed into the required position, and the
vacuum hold is released.
Horizontal feed for fixed-length rods. Single
rods of a given length are brought from the hopper
to the slot of a fixed plate by a moving plate. After
being gauged in the notched portion of the fixed
plate, each rod is moved to the chute by means of
a lever, and is removed from the chute by a vibrat-
ing table.
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61
Pin inserter. Pins, supplied from the parts-feeder, are raised to a ver-
tical position by a magnet arm. The pin drops through a guide cylin-
der when the electromagnet is turned off.
Cutoff and transfer devices for glass tubes. The upper part of a
rotating glass tube is held by a chuck (not shown). When the cutter
cuts the tube to a given length, the mandrel comes down and a
spring member (not shown) drops the tube on the chute.
Vertical feed for wires. Wires of fixed length are stacked vertically,
as illustrated. They are removed, one by one, as blocks A and B are
slid by a cam and lever (not shown) while the wires are pressed into
the hopper by a spring.
Feeding special-shaped parts. Parts of such special shapes as
shown are removed, one by one, in a given direction, and are
then moved individually into the corresponding indents on transfer
platforms.
Lateral feed for plain strips. Strips supplied from the parts-feeder
are put into the required position, one by one, by an arm that is part
of a D-drive linkage.
Vertical feed for rods. Rods supplied from the parts-feeder are fed
vertically by a direction drum and a pushing bar. The rod is then
drawn away by a chucking lever.
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SEVEN AUTOMATIC-FEED
MECHANISMS
The design of feed mechanisms for automatic or semiauto-
matic machines depends largely upon such factors as size,
shape, and character of the materials or parts that are to be fed
into a machine, and upon the kinds of operation to be per-
formed. Feed mechanisms can be simple conveyors that give
positive guidance, or they might include secure holding
devices if the parts are subjected to processing operations
while being fed through a machine. One of the functions of a
feed mechanism is to extract single pieces from a stack or
unassorted supply of stock. If the stock is a continuous strip of
metal, roll of paper, long bar, or tube, the mechanism must
maintain intermittent motion between processing operations.
These conditions are illustrated in the accompanying drawings
of feed mechanisms.
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