Note: Descriptions are shown in the official language in which they were submitted.
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ELECTRO-PNEUMATIC ACTUATOR
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FOR GLASSWARE FORMING MACHINE
BACKGROUND OF THE PRIOR ART
_
Field of the Invention
The invention relates generally to actuating
mechanisms for movingivarious components of a
glassware forming machine through their respective
operating cycles. More specifically, the invention
relates to pneumatic actuating mechanisms, the
velocity of which is lontrolled eletromechanically
in one direction of cyclical operation. Still more
specifically, the invention relates to pusher
mechanisms for moving glassware containers through a
predetermined arcuate path from a dead plate on to a
moving conveyor.
Description of the Prior Art
. ~
Pusher mechanisms for moving glassware articles
from a dead plate to ~ moving conveyor are well
known in the prior art. These devices generally
include a pneumatic pusher cylinder or head and a
rotary actuator means for moving it through a
predetermined arcuate path. In operation, each
pusher cylinder piston is in a retracted position
prior to the deposition of one or more glassware
articles on a corresponding dead plate. Extension
of the piston rod end by conventional pneumatic
means positions fingers at the end of the piston rod
near the glassware articles. Movement of the pusher
cylinder through an arcuate path is an operating
stroke which causes the fingers to contact the ware
and move it outwardly through an angle of
approximately 90 onto a moving conveyor belt. The
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piston rod is then retracted and the pusher cylinder
returned inwardly on a return stroke in the opposite
arcuate direction to complete the cycle.
The arcuate outward velocity of the pusher
cylinder is important since it must be slow enough
at the start of the cycle so as not to make unstable
or break the glas~swar~ upon contact with the fingers
and subsequently fast enough to match the arcuate
glassware velocity to the conveyor velocity.
In the prior art such pusher mechanisms are often
mechanical devices where the pusher cylinder piston
motion is caused pneumatically and the rotary motion
of the pusher cylinder is provided through
appropriate gearing from a common mechanical drive
train. Each section of the glassware forming
machine has a separate pusher mechanism associated
with it although each mechanism is driven by a
single motor via a common drive shaft. These prior
art mechanical devices prove troublesome from the
point of view of adjusting the timing of the
individual pusher mechanisms to the operation of
other mechanical components of the glassware forming
machine. Moreover, the velocity profile of the
arcuate movement of each pusher cylinder is
difficult to adjust because it depends upon the
profile of a cam associated with each mechanism.
Selection of a different velocity profile for the
pusher mechanism of one or more sections requires
replacement of the associated cam which means
stopping the entire conveyor.
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More recently, electronic pusher mechanisms
have been produced where each pusher mechanism may
be driven independently of the others according to a
predetermined velocity profile by an electric motor
controlled by a common control means. In some such
prior art units several velocity profiles may be
stored in memory and recalled at will. Examples of
such prior art electronic pushers are shown in U.S.
Patent Nos. 4,203,752 and 4,313,750~
Each of these prior art electronic pushers
requires a relatively large electric motor in
driving connection with the pusher cylinder in order
to control its arcuate movement in both directions
(both inward and outward arcuate strokes). Because
the pusher cylinder is a relatively massive
component these electric motors are necessarily
large and require high torque, thus making these
prior art electric pusher mechanisms costly and
inefficient. Moreover, the return stroke of the
pusher cylinder in such prior art electric pushers
is constrained by the ability of the electric motor
to move the relatively massive cylinder head.
Accordingly, it is an object of this invention
to produce an actuating apparatus for cyclically
moving a member through a predetermined arcuate
path. It is a further object to produce an
actuating apparatus having a fluidic driving means
and an electromechanical control means. Note that
the term "fluidic" as used herein means either
pneumatic or hydraulic. It is still another object
of this invention to produce such an apparatus
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wherein the velocity of the driving means is
controlled. A further object of khis invention is
to produce a pusher mechanism embodying the
principles of the foregoing actuating apparatus in
order to move a pusher cylinder through a
predetermined arcuate path.
Furthermore, prior art pusher mechanisms,
regardless of how the rotary actuator is driven,
generally supply pushout and retract air to the
pusher cylinder via two separate fluidic or air
passages. These passages are provided in the base
portion upon which the turntable (supporting the
pusher cylinder) is mounted and communicate with
ports in the turntable at predetermined angular
positions thereof. Consequently, the pushout and
retract functions are restricted to occur only at
certain points in the pusher mechanism's operating
cycle.
It is, therefore, another object of this
invention to produce a pusher mechanism wherein the
pusher cylinder may be actuated at any desired point
in the operating cycle thereof.
SU~MARY OF THE INVENTI~
These and other o~ljects of this invention are
achieved by the preferred embodiment disclosed
herein which is an apparatus for moving a member
cyclically along a predetermined path comprising:
fluidic drive means in driving connection with said
member and control means for controlling the
velocity of said fluidic drive means. More
particularly the invention comprises an apparatus
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for cylically driving a member along a predetermined
arcuate path comprising:
a motor;
a threaded shaft for being rotated by said motor;
a piston ar;d cylinder assembly for being
fluidically activated to move the piston;
a control nut in threaded engagement with
said threaded shaft;
means enabling contiguous engagement of
said control nut with said piston during motion
thereof in a predetermined direction;
converting means for converting the linear
motion of said piston to arcuate motion of said
member.
In one embodiment the converting means
comprises:
a first helically splined surface secured
to said piston for linear motion therewith; and
a rotatable hub having a second helically
splined surface in complementary engagement with
said first helically splined surface and for being
rotated by the linear motion thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
.... . . . . _ . _ _ . _ _ _ .. .. .
Figure 1 is a side elevational view, partly in
cross-section, of an electro-pneumatic drive
mechanism constructed in accordance with the
principles of this invention;
Figure 2 is a plan view of Figure 1 showing
some elements in phantom;
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Figure 3 is a sectional view of Figure 1 taken
along the lines 3-3;
Figure 4 is an elevational sectional view of
Figure 3, partially cut away, taken along the lines
4-4 and including a diagrammatic end view of a
pusher cylinder mounted on the turntable;
Figure 5 is a side elevational view, partly in
cross-section, of an alternate embodiment of this
invention;
Figure 6 is a side elevational view of another
alternate embodiment of the invention;
Figure 7 is a plan view of Figure 6.
DESCRIPTION OF THE PREFERRED EMBODIMENT
.
Referrin8 now to Figure 1 there is shown a side
elevational view, in cross-section, of electro-
pneumatic pusher mechanism 10 mounted adjacent
conveyor 12. Pusher mechanism 10 basically
comprises motor 14, piston and cylinder assembly 20,
turntable 22 and pusher cylinder 24 (shown partially
cut away).
Piston and cylinder assembly 20 comprises
cylinder wall 30, lower~ ahd upper~cylinder caps 32
and 34, respectively, and piston 40 which further
comprises piston body 42, and lower and upper piston
caps 44 and 46, respectively. Piston 40 is
pneumatically driven longitudinally within assembly
20 by conventional means. Air line 50 (best seen in
Figure 4) allows the communication of pushout air to
the bottom surface of lower piston cap 44 while
another air line 51 provides return air to top
surface of piston cap 46. All air lines within
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pusher 10 are fed from a manifold within mounting
bracket 60 best explained below with reference to
Figure 2.
While the driving force for piston 40 is
pneumatic, its long tudinal (linear) velocity is
controlled electrically in one direction by motor
14, as will be explained below. Motor 14 may be,
for example, a digital stepping motor under the
control of a microprocessor or other control circuit
(not shown). Alternatively, motor 14 may be a
linear actuator or other suitable means which may be
controlled to effect the operation described
herein.
Piston 40 is hollow and its lower cap 44 is
providecl with an axial aperture 70 to permit a shaft
72 to extend into the hollow piston. Shaft 72 has a
threaded end 73 and extends through lower cylinder
cap 32 and motor mounting bracket 15. Shaft 72 is
connected by a coupling 16 to the output shaft of
motor 14. Appropriate sealed bearings 74 and shaft
seals 75 serve to enable sealed rotation of shaft 72
within piston and cylinder assembly 20. A conical
oil flinger 71 is secured to shaft 72 to prevent oil
from dripping on motor 14, the oil being drained
through drain hole 71a. Threaded control nut 76 is
threadably engaged with shaft end 73 and, as best
seen in Figure 3, is prevented from rotating
therewith, thus constraining it to move only
longitudinally in response to rotation of shaft 72.
Similarly, rotation of piston 40 is prevented by key
78 cooperating with recess 79 tbest seen in Figure
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3). Restraining washer 77 is secured by a retaining
clip to the end of shaft 72 to limit motion of nut
76. Recess 77a provides clearance for washer 77.
Lower piston cap 44 is provided with a tapered
extension 45 which mates with a complementary bronze
insert 33 secured to cylinder end cap 32. Insert 33
provides a pneumatic cushion and facilitates
alignment and seal retention.
Upper piston cap 46 has welded or otherwise
secured to it a helically splined shaft 80 which is
in operative engagement with a complementarily
splined hub 82 rotatably mounted within upper
cylinder cap 34. Hub 82 is seoured by bolts 84
(only one of three shown) to spline cap 86 which is
provided with a recess 88 to receive shaft 80 upon
extension of piston 40. Bearing 90 permits rotation
of hub 82 and cap 86 relative to cylinder cap 34.
Hub 82 and cap 86 comprise a converting means for
converting the linear, longitudinal motion of piston
40 to horizontal arcuate motion of turntable 22.
Spline cap 86 is provided with a circular cross-
section extend-air passage 92 and retract-air
passage 94 for communicating pusher cylinder
operating air to turntable 22. These passages are
diametrically opposed as best seen in Figure 2. The
lower supply end port 96 of passage 92 and the lower
supply end port 98 of passage 94 are each of
circular cross-section and at predetermined
(vertical) locations on spline cap 86. Supply end
ports 96 and 98 open on to annular air channels 100
and 102, respectively, within sleeve 104. Air
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channels lO0 and 102 are in turn connected to
corresponding annular air channels 106 and 108,
respectively, in cylinder cap 34 by means of several
small supply apertures (not shown) in the wall of
sleeve 104. This construction was selected because
cylinder cap 34 is, in the preferred embodiment,
cast aluminum and it is not desirable to have spline
cap 86 rotate within such material. Thus, sleeve
104 is used as an intermediate bearing and may be
made of material such as bronze. A plurality of
seals 110 permit sealed rotation of cap 86 within
sleeve lO4.
Turntable 22 is bolted to the top of supporting
spline cap 86 so as to enable communication between
air passages 92 and 94 and 120 and 122,
respectively. As best seen in Figure 2 alignment of
turntable 22 on cap 86 is facilitated by forming the
top ends of air passages 92 and 9LI into arcuate
channels 124 and 126, respectively. Turntable 22 is
not keyed to spline cap 86 and air passages 124 and
126 are arcuate to enable alignment of the turntable
with the dead plate during installation.
Referring to Figures l and 2 it will be noted
that mounting bracket 60 also serves as an air
manifold to communicate air from supply lines (not
shown) connected to the bottom of bracket 60.
Bracket 60 contains four air passages 130, 131, 132
and 133. Passages 130 and 131 provide extend and
retract air, respectively to the pusher cylinder via
air channels 100 and 102 as explained above.
Passages 132 and 133 provide pushout and return air
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to pusher mechanism 10 via air lines 50 and 51,
respectively. The connection between passage 133
and air line 50 is best seen in Figure 4. Air
passage 132 is similarly connected in air line 51
(best seen in Figure 1).
Pusher mechanism 10 is connected to bracket 60
via mounting pin 140 which is secured to bracket 60
by n~t 142. Pivotable washer 144 and top nut 146
connect pusher mechanism 10 to pin 140 and provide a
quick release feature enabling the entire mechanism
to be easily replaced.
Referring now to Figure 3 it will be noted that
piston 40 is keyed within cylinder wall 30 by key 78
and recess 79. Nut 76 is l<eyed within piston 40 by
flange portions 150 and 152, the former being
provided with chamfered aperture 154 for receiving a
steel pin 156, best seen in ~igure 4. Lower piston
cap 44 is provided with aperture 157 for loose
mateable engagement with pin 156 to permit it to be
placed within operative distance to proximity
transducer 158 embedded within lower cylinder cap
32. Transducer 158 is secured by set screw 159 and
has wires 160 connected to a control means (not
, : ~ shown). The transducer serves to detect a zero
position of nut 76 in order to facilitate
synchronization.
An alternate embodiment of the invention is
shown in Figure 5 which discloses a side elevational
view of pusher mechanism 200 mounted between two
adjacent dead plates 202 and 204 and cooling boxes
206 and 208. Motor 210 is horizontally mounted to
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support plate 212 and operatively connected to
threaded shaft 214 by belt 216 and pulleys 218 and
220. The operation of shaft 214 within piston and
cylinder assembly 230 is similar to that of shaft 72
shown in Figure 1. Accordingly, the details of
assembly 230 will not be repeated here. It will be
noted that the embodiment of Figure 1 shows piston
40 in a retracted position while that of Figure 5
shows the piston in an extended position. One
difference between this horizontal embodiment and
the vertical embodiment shown in Figure 1 is that
shaft 232 secured to the piston has straight splines
and is fixedly connected to a link 240 which is in
turn pivotably connected to crank means 241 (i.e.
links 242 and 244). Link 244 is in turn fixedly
connected to support shaft 246 which supports
turntable 24~. The pusher cylinder is not shown
since any suitable conventional pusher arrangement
may be employed. Also, the details concerning the
unmentioned components shown in Figure 5 are not
presented since one skilled in the art will know how
to implement the embodiment disclosed.
In operation, link 240 moves linearly within
slot 241 formed in an extension of piston and
cylinder assembly 230. This causes pivotal motion
of crank means 241 which comprises links 242 and
244. Motion of link 240 causes link 242 to pivot
about the end of link 240 and link 244 to pivot
about the end of link 242. Since link 244 is
fixedly connected to shaft 246, the linear motion of
link 240 is converted to arcuate motion of turntable
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248.
Yet another alternate embodiment of the
invention is shown in Figures 6 and 7. Figure 7
also shows, diagrammatically, a conveyor, two dead
plates and containers. This embodiment shows the
use of pneumatic piston and cylinder assembly 300
for driving rack 302. Pinion 304 in operative
engagement with rack 302 converts the linear motion
of the piston to arcuate motion of pusher cylinder
306. Rack 302 has a cam follower 307 at its other
end and its velocity in one direction is controlled
by cam 308 which is rotated by motor 310 under the
control of a microprocessor or other control circuit
(not shown). Motion of the rack in the other
direction is totally pneumatic and unrestrained.
It will be noted that numerous other
fluidically driven means could be employed to move a
pusher cylinder or other member along a
predetermined arcuate path while controlling the
motion in only one direction. The control may be
applied at numerous points along the drive train
between the fluidic actuator and member to be
moved.
In operation, a control system (not shown)
initiates each operating cycle of pusher mechanism
10 at predetermined points in the machine (or
individual section) cycle. Each operating cycle
starts from the zero position sensed by proximity
transducer 158. Pusher cylinder 24 is placed in the
extend position and the control system provides to
motor 14 a predetermined series of digital pulses to
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rotate its output shaft according to a selected
velocity/displacement profile. Simultaneously,
extend air is applied to drive piston 40 upward on
its operating stroke. The linear velocity of piston
40 is controlled by the rate with which nut 76
advances along shaft 72, this rate being restrained
by the rotation of motor 14. This controlled linear
piston velocity in turn causes controlled rotation
of hub 82, turntable 22 and pusher cylinder 24. It
will be noted that the annular air channels around
spline cap 86 enable extension or retraction of the
piston of` pusher cylinder 24 at any point along its
arcuate path. Once pusher mechanism 10 has
completed its operating stroke (i.e. moving pusher
cylinder 24 arcuately in one direction to p]ace ware
on the conveyor) retract air is applied to retract
piston 40 (as well as the pusher cylinder piston)
and control signals are applied to motor 14 to
reverse its rotation. It will be noted that the
return stroke of piston 40 is pneumatically driven
without any control. Generally the piston's return
velocity will exceed the linear velocity of nut 76
to avoid contact therebetween on the return stroke.
Pusher mechanism 10 may be converted from right
to left-hand operation by changing splined shaft 80
and corresponding hub 82. In the preferred
em~odiment this requires changing the upper piston
cap 46.
Those skilled in the art will understand that
numerous modifications and improvements may be made
to the preferred embodiment of the invention
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disclosed herein without departing from the spirit
and scope thereof.
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