U.S. patent number 3,817,157 [Application Number 05/255,744] was granted by the patent office on 1974-06-18 for sheet position detector.
This patent grant is currently assigned to FMC Corporation. Invention is credited to William F. Andresen, Jr..
United States Patent |
3,817,157 |
Andresen, Jr. |
June 18, 1974 |
SHEET POSITION DETECTOR
Abstract
The present application discloses apparatus for combining two
sheets, by use of an adhesive, in a desired relation. One sheet,
which may have the adhesive applied thereto, is transported by an
intermittently operable conveyor to a nominal location where
combining with the other sheet occurs. Where such combining occurs,
a positioning mechanism, controlled by light transmitting and
receiving units, positions the other sheet with respect to the
transported sheet such that the combined sheets define a desired
positional relationship.
Inventors: |
Andresen, Jr.; William F.
(Chalfont, PA) |
Assignee: |
FMC Corporation (San Jose,
CA)
|
Family
ID: |
22969667 |
Appl.
No.: |
05/255,744 |
Filed: |
May 22, 1972 |
Current U.S.
Class: |
493/13; 156/364;
493/111 |
Current CPC
Class: |
B31B
50/00 (20170801); B31B 50/02 (20170801); B31B
50/024 (20170801); B31B 50/622 (20170801); B31B
2105/00 (20170801); B31B 2120/50 (20170801); B31B
2110/35 (20170801); B31B 2105/0024 (20170801); B31B
50/006 (20170801) |
Current International
Class: |
B31B
15/00 (20060101); B31B 15/02 (20060101); B31b
015/02 () |
Field of
Search: |
;93/54R,54.2,54.3
;156/364 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Juhasz; Andrew R.
Assistant Examiner: Gilden; Leon
Attorney, Agent or Firm: Pizzanelli; L. J. Tripp; C. E.
Claims
What is claimed is:
1. A box machine for registering glued wraps with boxes and placing
the boxes on the wrap, said machine comprising a frame, an indexed
conveyor on said frame for transporting longitudinally spaced and
glued wraps through a predetermined distance, means defining a
registration station for registering a box with and applying it to
a wrap, said registration station including a bracket member
mounting a box gripper for initially holding a box above a wrap,
means mounting said bracket member on said frame for shifting
motion parallel to the motion of said conveyor, a wrap sensor on
said bracket member for sensing a transverse edge of a wrap, an
actuator for shifting said bracket member and wrap sensor, control
means for said actuator including means for causing said actuator
to position said bracket member in an initial position wherein a
transverse edge of a wrap is adjacent to said sensor on completion
of each indexing of said conveyor, said control means including
means controlled by said sensor for causing said actuator to shift
said bracket member longitudinally to a registration position where
the sensor detects said transverse edge of the wrap, means for
thereupon holding said bracket member in said registration
position, and means for lowering the box gripper on said bracket
member for applying the registered box onto said wrap.
2. The box machine of claim 1, wherein said box gripper comprises
suction cups for engaging an upstanding wall of said box, means for
lowering said cups to place a box on said wrap, and means connected
to said bracket member and operable when said box is applied to
said wrap for connecting said suction cups to a source of air at
above atmospheric pressure air to release said box.
3. In a box machine including a longitudinally running conveyor
belt for transporting wraps, a registration station including
longitudinally shiftable means for gripping a box and applying it
to a wrap, means to index said conveyor belt to locate successive
wraps at said registration station, sensor means on said box
gripping means and controlling an actuator for causing shifting of
said box gripping means until a transverse edge of the wrap is
detected by said sensor means whereupon the box is registered with
the wrap, said sensor means comprising two laterally spaced but
longitudinally aligned sensors disposed above said conveyor, said
conveyor being formed with laterally spaced, longitudinal rows of
longitudinally spaced individual apertures, the apertures in one
row being staggered relative to those in the other row, the
apertures in each row having a longitudinal extent greater than the
spacing between adjacent pairs of apertures in the other row, each
of said sensors being aligned with one of said rows of apertures,
and circuit means connected to said sensors so that if either
sensor overlies a conveyor belt aperture after indexing of said
conveyor a shift signal is provided for shifting said box gripping
means to bring said sensors toward a transverse edge of the wrap,
said circuit means providing a stop signal when said transverse
edge of the wrap is brought under either sensor to thereby stop the
shifting movement of said box gripping means.
4. The box machine of claim 3, wherein each of said sensors
comprises light emitting sources below said conveyor and photocells
on said box gripping means.
5. The box machine of claim 3, wherein said sensor means comprises
sonic sending and receiving units mounted, respectively, below said
conveyor and on said box gripping means.
6. The box machine of claim 3, wherein said sensor means comprises
fluid discharge and fluid receiving units mounted, respectively,
below said conveyor and on said box gripping means.
7. The box machine of claim 1, wherein said actuator for moving
said box gripping bracket member comprises a hydraulic linear
actuator including a piston defining a rod-end liquid chamber and a
head-end liquid chamber, means for simultaneously supplying liquid
under pressure to one chamber while allowing liquid to be
discharged from the other chamber for shifting said bracket member,
and control means responsive to detection of the edge of said wrap
for blocking flow of liquid from said other chamber for arresting
the shifting of said bracket member.
8. A machine for assembling boxes with registered sheets including
a conveyor for transporting longitudinally spaced glued sheets, a
registration station associated with said conveyor, means at said
registration station for retaining boxes and applying them to
successive glued sheets, means for indexing said conveyor to locate
successive glued sheets at said registration station, means for
shifting said box retaining means in a plane parallel to said
conveyor to center the box over the glued sheet, means on said box
retaining means for detecting an edge of the glued sheet, and means
for lowering the box onto said sheet; the improvement wherein said
box retaining means is mounted for said shifting motion in a plane
parallel to the conveyor only in a direction parallel to the
direction of said conveyor motion, said detecting means sensing a
transverse edge only of said glued sheet, said box shifting means
comprising a control means responsive to said edge detecting means
for shifting said box retaining means linearly and parallel to the
direction of motion of said conveyor until said glued sheet edge is
detected, said control means including means for thereupon
arresting motion of said box retaining means to leave the box
centered over the glued sheet.
Description
BACKGROUND OF THE INVENTION
Apparatus for adhesively combining or unifying two sheets of
flexible material such as paper, plastics, leather, etc., has, up
until recent years involved a fair degree of hand labor which, to
respond to competitive conditions, has been continually diminished
by various innovations.
One field of activity which has provoked many of such innovations
is the rigid box making industry. In recent years the use of rigid
boxes has experienced a continual decline mainly as a result of
cost advantages resulting from use of erectable cartons. Cartons
can be produced in great quantities at a minimum unit labor charge
that is significantly less than rigid boxes. Of equal importance is
the fact that cartons can be shipped to the user in a collapsed
condition. Cartons, however, have not been accepted for packaging
quality products such as candles, perfumes and various
toiletries.
To produce the typical rigid box various types of machinery is used
and for purposes of illustration reference should be made to U.S.
Pat. No. 3,045,561 which is assigned to the assignee of the present
invention and by reference thereto it is intended that its
disclosure be incorporated herein.
Briefly, rectangular blanks of any desired dimensions, having a
small square slug removed from each corner, and provided with score
lines weakening the blank to facilitate bending, is erected by a
quad stayer. Erection is accomplished by applying small strips of
tape to each corner, The erected boxes may then be transported to a
conveyor supporting and conveying glued covering material, referred
to in the art as wraps, and positioned thereon by prior art
registering devices (designated as R in U.S. Pat. No. 3,045,561) or
applied to the wrap by hand which requires the operator to visually
register an erected box with each wrap. Oftentimes hand
registration is inaccurate resulting in a scrapped box part.
A significant improvement in registration devices is shown and
described in U.S. Pat. No. 3,400,031 which discloses the typical
intermittent motion wrap conveyor locating a series of glued spaced
wraps successively at a registration station located thereabove.
The registration station comprises an articulated frame for
releasably retaining a second sheet which will be applied to the
glued sheet located on the wrap conveyor. Light emitting and light
receiving elements, generally characterized as photocell units, are
mounted on the frame and are operable to detect a selected edge of
the sheet supported on the conveyor. These photocell units are
operably connected to a hydraulic servo system which is arranged to
adjust the articulated frame so that the sheet retained thereby is
vertically aligned with the sheet located on the conveyor. Once
alignment is achieved a plunger is actuated transferring the sheet
from the articulated frame to the sheet on the conveyor.
The above briefly described automatic registration unit, relies,
for its operation, on the principle of reflected light. More
particularly the photocell units emit a beam of light that
intercepts an edge of the sheet on the conveyor. The light is
reflected back to the photocell unit and picked up by a receptor
associated with each photocell unit. In brief, operation of the
automatic spotter shown in U.S. Pat. No. 3,400,031 is as follows.
After the sheet transporting conveyor has stopped at a nominal
location the articulated frame supporting the photocell units
commences to hunt until one photocell unit detects a portion of the
edge of the sheet on the conveyor. Once a particular photocell unit
locates the edge of the sheet operation of the actuator associated
therewith is interrupted. The other photocell will continue to
operate the actuator associated therewith until it also detects
another portion of the leading edge of the wrap and at such time
operation of the actuator, associated therewith is terminated. With
registration completed the sheets are then combined.
Experience with the automatic spotting system of the above
described patent revealed that proper operation will occur whenever
the color differences between the transporting conveyor belt and
the sheet are within the range of discrimination of the photocell
units. While some efforts have been made to determine the necessary
color differences within the range of discrimination of the
photocell units in practice this is determined by experimentation.
In the event the color differences are not within a range of
discrimination of the photocell units registration cannot be
accomplished. The problem of color differences can obviously be
solved by providing different colors of conveyor belts but
operators are reluctant to incur the added cost involved in
purchasing conveyor belts of various colors and the attendant costs
of time and labor for changing the belts.
SUMMARY OF THE INVENTION
It is the object and purpose of the present invention to provide a
sheet registration unit that fulfills the requirements of most
users while at the same time providing an arrangement which is
significantly less expensive than automatic spotting equipment now
in use. Its simplicity does not require maintenance skills that are
not usually found in box manufacturing operations. Moreover, it is
the object of the present invention to increase the cycle rate of
registration equipment over that provided by known automatic
spotting equipment and yet result in a degree of accuracy which is
commercially acceptable for the great majority of requirements.
In accordance with the present invention a conventional
intermittently operated wrap conveyor is provided associated with a
gluer that deposits regularly longitudinally spaced glued wrap on
the conveyor. Associated with the wrap conveyor is a mechanism for
transporting and registering a stayed box with a wrap located at a
spotting station. After the box is applied to the glued wrap, the
wrap conveyor is indexed to position a successive wrap at the
spotting station.
It is a primary feature of the present invention to provide an
atomatic sheet registration device which is responsive to the
interruption of sensing means which may consist of light, audio or
a fluidic coupling. At present the preferred form involves use of
light beams and photoelectric recepters which are in the path of
the wrap supported on the conveyor. The registration device is
operative to position a stayed box until one edge, preferably the
trailing edge, of the wrap intercepts the light beam indicating the
stayed box to be in proper alignment with the wrap. The stayed box
is then lowered and applied to the glued surface of the wrap.
Further in accordance with the present invention the wrap
transporting conveyor is provided with a series of apertures which
are located relative to each other to in effect provide a
longitudinally continuous opening so that a reference edge of the
wrap, regardless of its position relative to the openings, can be
detected. Although it is recognized that the apertures in the
conveyor belt can take various forms and located in various
patterns the disclosure of the present invention shows two rows of
staggered elongate apertures which are effective to provide, at any
transverse line, an opening for detection of the wrap. By providing
such an arrangement, which in effect is the equivalent to a
continuous elongate slot which might be defined by two belts being
slightly laterally spaced, there is no need to insure that
successive wraps are located at a particular position on the
transport conveyor.
In order to achieve fairly accurate registration by use of the
principles of the present invention it is a condition that the
longitudinal edges of the wrap (as distinguished from the leading
and trailing edges) are parallel to the longitudinal medium of the
conveyor and that the wrap is located a specified distance from one
reference edge of the conveyor. The reason for locating the wrap in
this manner, is because the registration device of the present
invention is limited to achieving registration along one axis and
such axis is parallel to the longitudinal median of the wrap
conveyor. Although this is recognized as a limitation as to the
flexibility of the registration device of the present invention
this would not constitute a factor against its commercial
acceptability due to its simplicity resulting in a substantially
less expensive registration device .
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of the box spotting device made in accordance
with the present invention shown with a fragmentary portion of a
wrap conveyor cooperable therewith,
FIG. 2 is a transverse section of FIG. 1 taken substantially along
the line 2--2 illustrating the relationship of the wrap conveyor,
the registration device and the box supply and feed unit,
FIG. 3 is a section taken substantially along line 3--3 of FIG.
2,
FIGS. 4, 5 and 6 are plan views showing the operational sequence
that takes place in registering a stayed box with the wrap,
FIG. 7 is a schematic of the hydro-pneumatic and electrical
controls for controlling the sequence of operation of the wrap
conveyor and the spotting device,
FIGS. 8 and 9 show, respectively, a sonic detector and a fluidic
detector that can be substituted for the photocells of the
preferred embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The overall arrangement of the preferred form of the sheet
registering apparatus is shown in FIGS. 1, 2 and 3 and reference
thereto will reveal a fragmentary upper portion of a frame
structure 10 having connected thereto, in laterally opposed
relation, a box feed and supply mechanism 12 and box spotting means
14 constructed in accordance with the principles of the present
invention. Supported on the frame structure 10, in any selected
manner, is a conveyor guide frame 16 slidably supporting an
intermittently operable conveyor belt 18 on which is deposited, in
a selected orientation and at longitudinally spaced intervals,
wraps W. The supply mechanism 12 provides a single file of boxes B
the leading one of which is transported laterally, relative to the
conveyor 18, by a transport means 20, (FIG. 2) to a retaining
device 22 which includes vacuum cups 24 that engage a longitudinal
side wall of a box B. FIG. 2 shows a box engaged by the vacuum cup
24 and at this point of the cycle it will be observed that the box
is a substantial distance above the wrap W.
The successive glued wraps are located on the conveyor 18 so that
their longitudinal edges LE are parallel to the longitudinal median
of the conveyor belt 18 and further the wraps are at regularly
spaced intervals and at a preselected transverse position such that
the distance, indicated by the dimension line S, (FIG. 1) is
constant or substantially constant. At each incremental advance of
the conveyor 18 the leading wrap is located out of register with
the overlying box and registration is always accomplished by moving
the box in the direction of conveyor movement.
At this time the box spotting means 14 is rendered operative, as
will be explained in detail hereinafter, to translate a bracket 28
(to the right as viewed in FIG. 1) until the box is in a prescribed
orientation with respect to the wrap located therebelow. To achieve
such alignment sensing means 30, mounted on the bracket 28 and
responding to light sources 32, provides a signal for operating a
linear actuator 34 having the end of its rod rigidly connected to
the bracket 28 at 36. The linear actuator 34 is operated to
translate the bracket 28 to the right (FIG. 1) until the trailing
edge of the wrap located at the spotting position interrupts the
light received from the sources 32. When this condition is attained
the box is in alignment with the wrap directly therebelow providing
a signal for operating a box lowering mechanism, generally
indicated by the numeral 38, (FIG. 2) including an electric clutch
brake device 40 which is intermittently operable to rotate a cam 42
arranged to reciprocate flexible shafts 44 and 46 which are rigidly
connected to blocks 48 carrying the vacuum cups 24.
After the box held by the vacuum cups 24 is lowered onto the wrap,
vacuum to the cups is interrupted and a slight over-pressure is
applied to reliably release the box. Immediately thereafter the
flexible shafts 44 and 46 are actuated raising the vacuum cups to
the position shown in FIG. 2 The conveyor 18 may then be advanced
to locate a subsequent wrap at the spotting station.
In accordance with one novel feature of the present invention the
simplified box spotting means 14 depends for its operation on the
fact that the successive wraps carried by the conveyor 18 are at
regularly spaced intervals and the wrap has one of its longitudinal
edges LS located parallel to and at a fixed distance from a
reference line, with such distance being indicated by the dimension
line S. Referring to FIG. 1 it will be seen that three successive
wraps are shown and they are identified as W-1, W-2 and W-3. The
wrap W-2 is located below the spotting means 14 and the condition
is shown before the box overlying the wrap is brought in register
therewith. The wraps are located on the conveyor 18 such that when
the successive wraps arrive at the spotting station the trailing
end of the wrap is always in advance of the sensing means 30 so
that the light, originating from the light sources 32, is detected
by photocells 50 and 52 carried by a bracket structure 54 which is
rigidly mounted on the bracket 28 and is adjusted by a screw
56.
As shown in FIGS. 2 and 3 the conveyor frame 16 is provided with a
channel 58 in which are located a pair of light bulbs 60 and 62
radiating light through two rows of elongate staggered apertures 64
and 66 arranged in this manner so that light emitted from either
one of the bulbs is always detected by one of the photocells 50 or
52 irrespective of the relative position of the wrap. As will be
described hereinafter, the photocells 50 and 52 are connected in
parallel to provide a signal at all times to operate the linear
actuator 34 for alignment of the box with the wrap.
The box spotting means 14, which includes the bracket 28, is
mounted on a longitudinal structural member 68 fixed to the frame
structure 10. Rigidly secured to the member 68 are bored blocks 70
and 72 slidably receiving connecting rods 74 and 76. Any desired
means, such as lock screws, can be provided to lock the blocks 70
and 72 in a desired lateral position. On respective ends of each
rod 74 and 76 lugs 78 and 80 are rigidly mounted. Each lug is
provided with a bore for slidably receiving a guide rod 82 having
its ends fixed in the bracket 28. The lug 78, is made larger than
the lug 80 for the purpose of mounting the linear actuator 34 in a
depending saddle 84.
To provide linear guides for the flexible shafts 44 and 46 bearing
blocks 86 and 88, slidably receiving the shafts 44 and 46, are
rigidly mounted on the bracket 28 as shown in FIGS. 1 and 3. As
mentioned previously, the ends of the flexible shafts 44 and 46 are
rigidly connected to members 48 which mount the vacuum cups 24.
With the wrap W-2 (FIG. 1) in the illustrated position, light
emanating from the bulbs 60 and 62 pass through the apertures
located directly below the photocells 50 and 52. The light energy
energizes one or both of the photocells, and through appropriate
controls, later to be described in detail, the linear actuator 34
is retracted, shifting the bracket 28 and the parts carried
thereby, to the right as viewed in FIG. 1 until the trailing edge
of the wrap interrupts the light beam stopping movement of the
actuator 34. As a consequence the box held by the vacuum cups 24 is
in register with the wrap at this time.
As shown in FIGS. 2 and 3 the box lowering mechanism 38, which is
rendered operative after the wrap has been aligned with the box,
comprises an input shaft 90 driven by a belt 92 trained about a
pulley 94 keyed on the shaft 90. The shaft 90 is keyed to the
clutch-brake 40. The clutch-brake 40 includes a clutch portion 40c
and a brake portion 40b. When the clutch 40c is energized and the
brake 40b is deenergized, the shaft 90 is coupled to drive an
output shaft 96. The shaft portions 90 and 96 are suitably
rotatably supported in structural members 98 which form part of the
frame structure 10. Upon rotation of the shaft 96, the cam 42,
which is keyed thereon, also rotates, and through a cam follower
roller 100 in a cam track 102, the flexible shafts 44 and 46 are
reciprocated by virtue of their connection to a crosshead 104 on
which the cam follower roller 100 is rotatably mounted.
After the flexible shafts 44 and 46 are actuated to raise the
vacuum cups 24 to their starting position, a subsequent box from
the box feed and supply mechanism 12 is fed laterally toward the
conveyor 18 by a feed conveyor 105 to a position where it can be
engaged and transported by the transport means 20. Although an
exemplary transport means is shown it is to be understood that such
means can take various forms as long as the requirement of
sequentially feeding a box to the vacuum cups 24 is fulfilled.
With respect to FIGS. 4, 5 and 6 which show a wrap being
transported to the spotting station (FIG. 4), located at the
spotting station prior to registration (FIG. 5) and when
registration of the box with the wrap has been attained (FIG. 6),
it should be noted that the sensing means 30 always has one of the
photocells 50 and 52 exposed to the light emanating from one of the
lights 60 or 62. For example, in FIG. 5 after the conveyor 18 has
been stopped, locating the wrap at the registration station, light
to one of the photocells is interrupted as that photocell passes
over the belt portion between the apertures in a row. More
particularly, when the linear actuator 34 is retracted from its
extended position, the light which will be detected by the
photocell 50 will be interrupted as it traverses the conveyor
portion between the two adjacent apertures 64 in the row of
apertures directly thereunder while the photocell 52 will be
exposed to the light conditioning the control circuit to continue
operation of the linear actuator 34. In FIG. 6 the same effect is
experienced by the photocell 52 when it traverses the conveyor belt
portion between adjacent apertures 66 in the row aligned therewith
but at this time photocell 50 is conducting. FIG. 6 shows the
sensing means 30 overlying the trailing edge of the wrap W at which
point the light to both photocells is inerrupted arresting movement
of the linear actuator 34. As explained above under these
conditions the box is in alignment with the wrap. Thus the two rows
of elongate staggered apertures result in providing the equivalent
to a continuous elongate slot much as would exist if two laterally
spaced conveyor belts were substituted for the conveyor belt 18. It
is, however, to be appreciated that it is entirely possible to
provide a continuous signal by providing two rows of apertures of
various configurations and various patterns other than that shown
and described herein.
Since the box registration device of the present invention is used
in combination with various other machinery coordinated to produce
a wrapped box part, a signal to initiate and terminate operation of
the spotting device is derived from such machinery. Reference to
U.S. Pat. No. 3,045,561, mentioned hereinabove, illustrating a
complete box line identifies the wrapper by the letter M. The
wrapper operates to complete applying the wrap to the vertical side
walls of the box and when its cycle of operation is complete or
substantially complete a signal is given to the gluer G and the
wrapper conveyor belt 18 to index a prescribed amount and thus
commences operation of the spotting device. With this brief
explanation of the manner in which the box spotting device of the
present invention may be integrated with other mechanisms reference
is now made to FIG. 7 which shows a schematic diagram of the
control devices for the spotting device.
A single revolution shaft 106, having keyed thereon a cam 108 and a
sprocket 110, effects intermittent movement of the conveyor 18
through a chain 112 and a sprocket 114 driving a shaft 116 on which
is fixed a pulley 118. The cam 108 is provided with a rise portion
108a operating a linkage 120 for opening and closing switches SW-1
and SW-2, which, when closed, electrically connect components of
the electrical circuit across the supply lines L1 and L2. A relay
122, electrically connected to photocells 50 and 52, is connected
across lines L1 and L2 through switch SW-1. Light sources 60 and 62
are connected across the lines L1 and L2 through branch lead 124.
In a branch lead 126, connecting a solenoid 128 to the line L2
through the switch S-2, are normally closed contacts CR1 operated
by the relay 122. Solenoid 128 is also connected to the line L1
through branch lead 130. The solenoid 128 operates a valve 132 that
connects the head end of the actuator 34, through conduit 134, with
a source of hydraulic fluid in an accumulator 136. The rod end of
the actuator 34 is connected to another source of hydraulic fluid
in an accumulator 138 through a conduit 140. The accumulators 136
and 138 are selectively connectible, through a source of pressure
air, communicated thereto through a conduit 142 by a solenoid
operated valve 144. The solenoid 156 is connected across the lines
L1 and L2 through branch leads 130 and 126.
Vacuum is supplied to the vacuum cup 24 through a conduit 148 which
is connected to a vacuum pump 146. In the conduit 148 is a vacuum
switch 150 in series with the switch SW-2. A branch conduit 152
makes communication with the vacuum conduit 148 and it is
associated with a valve 154 which is operable to establish
communication between the air pressure line 142 and the vacuum
conduit 148 at that point in the cycle after the box has been
applied to the wrap. In lines 134 and 140 hand valves 135 and 137
are provided for drawing make-up fluid from a source 139.
To explain the operation of the various components shown in FIG. 7
one cycle of operation will be described. On signal from the
wrapper the shaft 106 rotates one revolution indexing the conveyor
18 to position a glued wrap at the registration station and
switches SW-1 and SW-2 are closed by actuation of the linkage 120
by the rise portion 108a of the cam 108. Closing switch SW-1
electrically connects the relay 122 to the lines L1 and L2 and
concurrently therewith the photocells 50 and 52 are rendered
conducting. Since relay contacts CR1 in line 126 are closed the
solenoid 128 is energized establishing communication between the
head end of the linear actuator 34 with the fluid accumulator 136.
The solenoid 156, of valve 144, is energized upon the closing of
switch SW-2 to position the spool 144a connecting air line 142 with
the accumulator 138. The head pressure communicated by line 142
expels fluid from the accumulator 138 into the conduit 140 to the
rod end of the linear actuator 34. With the piston of the linear
actuator 34 moving to the right, as viewed in FIG. 7, the bracket
28 which is rigidly connected to the piston rod translates the
bracket, the sensing means 30, and the box carried by the vacuum
cups 24, as a unit. Such movement continues until the trailing edge
of the wrap interrupts the beam of light received by the photocells
50 and 52 deenergizing the relay 122 and opening contacts CR1 in
line 126. Opening the contacts CR1 deenergizes the solenoid 128
shifting the spool of the valve 132 to block flow of fluid from the
head end of the linear actuator 34. A check valve 158 in the loop
160 also serves to retain the fluid in the head end of the actuator
34.
Since a stayed box B is retained by the vacuum cups 24 and this
condition must exist before the registration device can operate, as
it is necessary that the vacuum switch 150 in line 126 be closed,
the electromagnetic clutch-brake 40, which may be connected in
series with the vacuum switch 150, is actuated deenergizing the
brake 40b and energizing the clutch 40c so that lowering of the box
onto the registered wrap is effected. When the box has been applied
to the wrap the valve 154 in line 152 is actuated by a stem 155
connecting pressure air from line 142 with the line 152 which
communicates with the line 148. Such action not only interrupts
vacuum to the cups 124 but also applies a slight overpressure
reliably releasing the vacuum cups 24 from the box after it as been
applied to the wrap.
As soon as the box is released by the vacuum cups 24, the vacuum
switch 150 in line 126 opens deenergizing the solenoid 156 shifting
the spool 144a to establish communication between the pressure air
line 142 and the accumulator 136. The air admitted to the
accumulator 136 forces fluid therefrom into the conduit 134 through
the check valve 158 into loop 160 and to the head end of actuator
34 moving the piston of the actuator to the left as viewed in FIG.
7. Fluid from the rod end of the actuator is returned through line
140 to the accumulator 138. While the linear actuator assumes the
condition shown in FIG. 7 the vacuum cups 24 are returned to their
upper position effected by deenergization of the clutch 40c and
energization of the brake 40b. Upon command from the wrapper (shown
in U.S. Pat. No. 3,045,561 referred to above) shaft 106 is rotated
one revolution positioning another wrap at the registration station
during which time another box from the feed and supply mechanism 12
is transported to the vacuum cups by the transport means 120. Once
these conditions have been fulfilled the registration device is
prepared to repeat the above described operation.
Modified forms of the wrap sensing means 30 are shown in FIGS. 8
and 9, which, for the purposes of simplicity, only a portion of the
subject matter of FIG. 7 is repeated. It is to be understood that
the common elements shown in FIGS. 8 and 9 will be assigned the
same numerals as FIG. 7 but the particular sensing means will be
assigned distinguishing numerals.
Referring first to FIG. 8 the sensing means 30a in this particular
modification comprise sonic receiving units 50a and 52a located in
vertical alignment with sonic sending units 60a and 62a. As in the
case of the photocell units, the sonic sending and receiving units
are in alignment with the apertures in the conveyor belt 18 and are
connected in parallel by lines 70a and 70b to a relay-amplifier
122a so that one of the receiving units 50a or 52a is at all times
receiving a signal from the sending unit 60a or 62a also connected
in parallel to relay-amplifier 122a. Only when the trailing edge of
the wrap shields both receiving units, indicating the box to be in
register with the wrap, will a signal be sent to the
relay-amplifier 122a which will cause the amplifier 122a to open
the contacts CR1 in line 126. As in the previous case, opening
contacts CR1 shifts the spool of the valve 132 blocking the line
134 thereby preventing retraction of the linear actuator 34. Sonic
detecting devices which are suitable for the described purpose are
manufactured by Delavan Manufacturing Company of West Des Moines,
Iowa, which in addition to the sonic senders and receivers
manufactures appropriate controls includ1ng amplifiers and relays
for fulfilling various control functions.
The wrap detecting arrangement shown in FIG. 9 schematically
discloses a preferred arrangement in the event it is desired to use
fluidic detecting devices. Such an arrangement includes an OR/NOR
gate 122b which is connected, by means of a conduit 170, to a
source of air under pressure flowing through the gate 122b and
discharging from 170a or 170b depending on the absence or the
presence of a diverting stream of air. Air under pressure supplied
through a line 51 flows to receivers 50b and 52b but the value of
pressure to the receivers is controlled by adjustable throttles 50c
and 52c in lines 53 and 55 which communicate with supply lines 51.
Air at line pressure from the line 51 is discharged through
emitters 60b and 62b, which, as shown in FIG. 9, are located
directly below the receivers 50b and 52b respectively. The small
quantity of air continually discharged through the receivers 50b
and 52b by virtue of the throttles 50c and 52c is for the purpose
of preventing contamination of the receivers but the value of
pressure is such that control function of the OR/NOR gate 122b is
not affected.
Since the fluidic receivers 50b and 52b, as well as the fluidic
emitters 60b and 62b, are connected in parallel, air discharged by
the emitters 60b and 62b will always be received by one of the
receivers 50b or 52b. Under these conditions control pressure will
be communicated to the OR/NOR gate 122b through lines 50d or 52d
providing a biasing air stream to insure that air derived from the
line 170 is directed to the branch line 170a whose output operates
the pressure switch 172 connecting a relay coil 174 across the
supply lines L1 and L2. With the relay coil 174 energized the relay
contacts CR1 in line 126 are closed allowing pressure fluid from
the head end of actuator 34 to return to the accumulator 136.
When the edge of the wrap interrupts the stream of air from both of
the emitters 60b and 62b, occurring when the box has been aligned
with the wrap, biasing pressure fluid in line 50d and 52d is
interrupted and the air stream from line 170 is diverted to branch
line 170b. This occurrence opens the pressure switch 172 which
deenergizes the relay coil 174 opening the normally closed contacts
CR1 in line 126. With the relay contacts CR1 open the solenoid 128
is deenergized shifting the spool of the valve 132 to block flow of
fluid in the line 134. Movement of the bracket 28 is
instantaneously arrested, conditioning the circuit to lower the box
onto the wrap registered therewith.
Fluidic controls to perform the above described functions are
provided by Corning Fluidic Products Department, Corning Glass
Works, Corning, New York and are identified by Part Number
191453.
It is to be realized that operation of the clutch-brake 40 proceeds
as described in the preferred embodiment.
Although the best mode contemplated for carrying out the present
invention has been herein shown and described, it will be apparent
that modification and variation may be made without departing from
what is regarded to be the subject matter of the invention.
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