U.S. patent number 3,698,755 [Application Number 05/138,556] was granted by the patent office on 1972-10-17 for vacuum head magnetic valve construction for pallet loader.
This patent grant is currently assigned to Diebold, Incorporated. Invention is credited to Gordon J. Sinclair.
United States Patent |
3,698,755 |
Sinclair |
October 17, 1972 |
VACUUM HEAD MAGNETIC VALVE CONSTRUCTION FOR PALLET LOADER
Abstract
A magnetic valve vacuum head construction for pallet loaders,
for hoisting, or lifting rigid, sealed cartons, packages, boxes, or
cases to transfer them to or from and to load or unload them to or
from pallets for palletized material handling. The vacuum head has
lift plate means with a work-engaging face communicating through a
series of box-like cells and a mask plate to the plenum chamber of
a blower mounted on the head supplying the suction. A series of
orifices in the mask plate each form airflow passages between the
cells and the plenum chamber. Each valve has a magnetic metal plate
of larger dimensions than those of the controlled orifice and an
actuator connected to the magnetic plate formed of nonmagnetic
material. The actuator extends through the orifice and normally
projects below the work-engaging face of the vacuum head to engage
the cartons to be hoisted for opening the magnetic valve.
Inventors: |
Sinclair; Gordon J. (East
Syracuse, NY) |
Assignee: |
Diebold, Incorporated (Canton,
OH)
|
Family
ID: |
22482561 |
Appl.
No.: |
05/138,556 |
Filed: |
April 29, 1971 |
Current U.S.
Class: |
294/65;
414/792.9 |
Current CPC
Class: |
B66C
1/0243 (20130101); B66C 1/0206 (20130101); B66C
1/0281 (20130101) |
Current International
Class: |
B66C
1/02 (20060101); B66C 1/00 (20060101); B66c
001/02 () |
Field of
Search: |
;294/64,65,65.5
;214/1BS,1BT,6FS,8.5D,65SG ;248/362,363 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Blunk; Evon C.
Assistant Examiner: Cherry; Johnny D.
Claims
I claim:
1. In a pallet loader vacuum head of a type having a lift face,
having walls forming a plenum chamber, and having an exhauster
communicating with the plenum chamber; the combination of one
plenum chamber wall being formed with a multiplicity of airflow
orifices for communication between the lift face and the plenum
chamber; a magnetic valve normally closing each orifice; and each
valve including a magnetized metal plate located in the plenum
chamber larger than the orifice closed thereby, and an actuator
connected to the plate, and extending outward through the orifice,
and projecting beyond the lift face, and adapted to contact an
article to be lifted when the head is lowered to engage the lift
face with such article; whereby contact of the actuator with such
article moves the valve plate out of valve-closing position to
permit airflow through said orifice to the plenum chamber when the
exhauster is operating to provide suction force to lift such
article.
2. The construction defined in claim 1 in which the actuator is
formed of nonmetallic material.
3. The construction defined in claim 1 in which the actuator is
formed of plastic material.
4. The construction defined in claim 1 in which said one plenum
chamber wall includes grill means formed with a multiplicity of
cells, in which an airflow orifice communicates through each cell
with the lift face, and in which the actuator for each valve
extends through the corresponding cell.
5. The construction defined in claim 4 in which each actuator has a
depending leg at each end, in which each leg has a foot, and in
which shoulder means is formed in each cell engaged by said feet to
limit valve opening movement of the actuator.
6. The construction defined in claim 4 in which each actuator has a
depending leg at each end, and in which a central guide vane of
greater length than said legs projects downward intermediate of and
spaced from said legs.
7. The construction defined in claim 1 in which said one plenum
chamber wall comprises a mask plate and a grill; in which the
orifices are formed in the mask plate; in which each orifice
comprises a narrow elongated slot; and in which the grill is formed
with a plurality of cells, one cell communicating with its
corresponding slot.
8. The construction defined in claim 6 in which each orifice
comprises a narrow elongated slot, in which the actuator legs and
guide vane have common lateral parallel faces spaced to provide
uniform thickness less than the width of the slot through which the
actuator extends.
9. The construction defined in claim 1 in which the magnetic valve
plate has a central opening, in which the actuator has a central
upwardly projected neck extending through said plate opening, and
in which means is provided connecting said neck to said plate.
10. The construction defined in claim 9 in which means is provided
at the ends of each actuator interlocking with the plate to prevent
relative movement between the plate and actuator.
11. Vacuum head construction for a pallet loader including walls
forming an exhauster plenum chamber, lift plate means forming one
of the plenum chamber walls; the lift plate means including a grill
structure and a metal mask plate; the grill structure being formed
with a plurality of cells and having a lift face and a back face;
the mask plate having a chamber face and an outer face; the grill
structure and mask plate being connected with the grill back face
adjacent the mask plate outer face; a plurality of elongated
airflow slots formed in the mask plate, one slot communicating with
each cell; magnetic valve means normally closing each slot
including a magnetic plate and a flat actuator connected to the
magnetic plate; the magnetic plate being larger than the slot
closed thereby and held in contact with the mask plate chamber face
by magnetic attraction when in valve-closed position; and the
actuator extending through the slot and its corresponding cell and
projecting beyond the grill lift face; whereby when the vacuum head
is lowered to engage its lift face with articles to be lifted, all
projecting actuators contacting such articles are moved incident to
such contact and the lowering of the head and move the valves to
open position to permit airflow through the cells and valve-opened
slots to the plenum chamber providing suction to lift such
articles.
12. The construction defined in claim 11 in which the actuator is
formed of plastic material and is smaller in cross section than the
elongated slot through which it extends; and in which
interengageable stop means are provided on the actuator and cell
walls to limit valve opening movement of the actuator.
13. The construction defined in claim 11 in which each flat
actuator has a thickness less than the width of the slot through
which it extends for free slidable movement through such slot and
to permit airflow around the actuator and through the slot when the
valve is in open position.
14. The construction defined in claim 11 in which the grill
structure has walls forming the cells; in which the walls of each
cell have a stop shoulder formed therein intermediate the grill
lift and back faces; and in which the actuator in each cell has
projecting feet engageable with said stop shoulder to limit opening
movement of the actuator.
15. The construction defined in claim 11 in which each actuator has
legs at each end extending through its corresponding slot and cell;
in which the actuator has a central guide member of greater length
than the legs extending through the cell spaced from the legs; and
in which the guide member engages an article to be lifted for
moving the actuator to open the valve.
16. The construction defined in claim 11 in which the grill
structure has subway-grating-type cellular box-like side and end
walls forming the plurality of cells, in which each cell has a
thick bottom wall in which a diamond-shaped opening is formed in
each bottom wall communicating with the corresponding mask plate
slot, and in which the magnetic valve actuator extends through said
diamond-shaped opening.
17. The construction defined in claim 16 in which the cell bottom
wall has a shoulder face intermediate the grill lift and back faces
extending between the diamond-shaped opening and the cell side and
end walls.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to pallet loader vacuum heads and more
particularly to a magnetic valve construction for such vacuum
heads. Especially the invention relates to a universal vacuum head
construction for pallet loaders adapted to handle different package
patterns for palletizing the packages in overlapping tiers or
layers wherein a series of magnetic valves normally closed are
opened by contact with the packages to be hoisted or handled by the
vacuum head to supply airflow providing the package lifting
force.
2. Description of the Prior Art
The work contact or lift faces of pallet loader vacuum heads have
had special partitioned patterns for each particular pattern of a
carton layer to be handled by the head. Masks were used for the
partitioned lift faces having sealing strips corresponding to zones
between adjacent cartons in the pattern. Such masks essentially are
rubber gaskets defining the sealing strip pattern as well as the
outer edges or perimeter of the head. A separate mask has been
required for each pattern and the masks must be changed when
patterns are changed. The operation of such pallet loader vacuum
head equipment required a high vacuum, with low volume airflow,
say, 400 cu. ft. of air per minute passing through a centrifugal
blower-exhauster mounted on the head and maintaining a vacuum of 4
inches of mercury.
Another vacuum head construction has used a subway-grating type
grill or cellular structure to form the work-engaging member
providing the lift face of the vacuum head. Such heads have
operated on high volume, low vacuum airflow through the exhauster
of about 1400 cubic feet of air per minute at a vacuum of 2 inches
of mercury. Such a head can accept different patterns without
changing the mask. Where one mask is used for different patterns,
areas not contacting a carton to be lifted are blocked out with a
sheet metal plate.
High volume, low vacuum heads accommodating various patterns,
preferably have used valves for each cell of the grill structure.
Hundreds of valves may be involved and it is impractical to
remotely control such valves because this would involve a
complicated procedure to select the proper valves to be opened and
closed in order to change patterns to accept a particular
pattern.
Thus, automatically operated valves have been used to provide
universal vacuum heads which automatically accept any carton
pattern, and wherein the valves are closed by the vacuum airflow in
each cell of the vacuum head not covered by a carton to be
lifted.
Various types of valves have been used including spring-loaded
valves, flexible spring material valves, weighted valves, etc. Some
of these valves are actuated by contact with the cartons. Where
weighted valves are used the weight of the valves becomes part of
the load to be lifted and increases the power requirements, and
such increase of power requirements should be minimized.
Flexible spring material valves have not proven entirely
satisfactory since it is difficult to provide hundreds of flexible
spring elements with identical spring characteristics, which result
in nonuniform actuation of the valves under existing airflow
conditions because of nonuniform spring characteristics.
Similarly, spring-loaded valves require close tolerances to be
maintained in manufacture and use if uniform operating
characteristics are to be present in the multitude of cells.
Insofar as I am aware, no prior art pallet loader vacuum head valve
construction has been entirely satisfactory for controlling the
flow of air through airflow orifices in heads having cellular
work-engaging faces.
SUMMARY OF THE INVENTION
Objectives of the invention include providing a magnetic valve
construction for the vacuum head of a pallet loader; providing such
valves for automatically controlling the flow of air through
orifices in a cellular vacuum head; providing a pallet loader
vacuum head, the lifting face of which is divided into cells formed
by a subway-grating type grill, with an airflow orifice connected
to each cell, and a magnetic valve normally closing each orifice;
providing a magnetic valve formed of a magnetized metal plate
larger than the airflow orifice to be closed and a plastic material
actuator attached to the plate and slidably movable through its
orifice between open and closed valve positions; providing such a
magnetic valve with stop means on its actuator which engages a
portion of the grill to limit opening movement of the valve;
providing an elongated slot to form each orifice and depending legs
at the ends of the actuator which extend through the slots, with
feet on the legs which engage the grill to limit opening movement
of the valve; providing each actuator with a centrally located
guide vane spaced between its legs slidably movable through the
central portion of its corresponding orifice slot; providing the
actuator with a centrally located, upwardly disposed stem connected
to the magnetized metal plate; providing an upwardly disposed
projection at each end of the actuator received in cavities in the
magnetized metal plate to maintain assembly of the actuator and
magnet without relative movement; and providing a universal vacuum
head magnetic valve construction which is inexpensive to
manufacture, easy to assemble, sturdy and durable in use, and which
eliminates difficulties heretofore encountered, achieves the
objectives indicated and solves problems and satisfies needs
existing in the art.
These objects and advantages are obtained by the vacuum head
magnetic valve construction for pallet loaders including a
subway-grating-type cellular grill structure forming a plurality of
cells, the grill having a work-engaging or lift face and a back
face, a metal mask plate mounted on the back face of the grill; a
plurality of elongated slots formed in the mask plate, one slot
communicating with each cell forming a limited airflow orifice for
each cell; magnetic valve means normally closing each slot; each
valve preferably comprising a magnetized metal plate larger than
the slot controlled by the valve, and an actuator formed of
nonmagnetic preferably plastic material connected to the plate; the
actuator being slidably movable through its slot; the grill having
stop shoulder means formed in each cell; stop means formed on each
actuator engageable with the cell shoulder means to limit the
opening movement of the valve; the actuator being flat and having a
thickness less than the width of the slot for free movement in the
slot; the actuator having a depending leg at each end forming the
stop means and a central guide intermediate and spaced from the
legs; the actuator having an upwardly disposed stem connected with
the plate; projections at each end of the actuator engaged in
suitable cavities in the plate to maintain assembly of the plate
and actuator without relative movement; the head also including a
centrifugal blower-exhauster, walls forming a plenum chamber for
the exhauster, the mask plate comprising a wall portion of the
plenum chamber walls, the mask plate slots communicating with the
plenum chamber, and the magnetized plates being located within the
plenum chamber; the valve plates normally magnetically seating on
the mask plate closing their respective cell orifice slots to
prevent vacuum airflow loss through the slots when the exhauster is
operating; the actuator feet projecting from the lifting face of
the grill when the valves are normally closed; and the actuator
guide being engaged with cartons to be lifted upon lowering the
vacuum head onto such cartons and actuated by pressure of cartons
to open the valves and establish vacuum airflow through said slots
into the plenum chamber to provide lifting power for holding the
cartons to be lifted.
BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the invention -- illustrative of the best
mode in which applicant has contemplated applying the principles --
is set forth in detail in the following description, is illustrated
in the accompanying drawings, and is particularly and distinctly
pointed out and set forth in the appended claims.
FIG. 1 is a perspective view of a pallet loader equipped with a
vacuum head provided with the improved magnetic valve
construction;
FIG. 2 is an enlarged bottom plan of a corner portion of the
magnetic valve vacuum head grill;
FIG. 3 is an enlarged top plan view of the corner portion of the
grill shown in FIG. 2;
FIG. 4 is a further enlarged longitudinal sectional view taken on
the line 4--4, FIG. 3, showing one of the magnetic valves in
normally closed position;
FIG. 5 is a view similar to FIG. 4 showing the magnetic valve
actuated to open position by contact of the valve actuator with a
carton to be lifted by the vacuum head;
FIG. 6 is a transverse section taken on the line 6--6, FIG. 4;
FIG. 7 is a side elevation of one of the plastic valve actuators
before assembly; and
FIG. 8 is an end view of the actuator shown in FIG. 7.
Similar numerals refer to similar parts throughout the
drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A typical pallet loader 1 includes overhead track rails 2 upon
which a carriage 3 is movable, from which a vacuum head generally
indicated at 4 is suspended for raising and lowering.
A centrifugal blower, air-exhauster 5 is mounted on vacuum head 4.
Carriage 3 may be moved along the track 2 between several
positions, one at left end of track 2, one at right end of track 2,
and a third intermediate position at the top of the tower 3A, above
sections of a conveyor 3B where cartons to be loaded are delivered
and arranged in a desired pattern to form a layer of a palletized
load.
Carriage 3 may be moved to a position above an assembled layer of
cartons 6 on conveyor section 3B, the vacuum head 4 then is lowered
and the layer 6 picked up. Then head 4 is raised and carriage 3 is
moved to a position such as shown in FIG. 1 above pallet 7,
whereupon it may be lowered to place the carton layer 6 upon other
layers located on pallet 7 as shown in FIG. 1. When the desired
number of layers 6 have been deposited on pallet 7 the cartons are
strapped to pallet 7 to form a palletized load handled in the usual
manner. The pallet loader construction thus far described is
typical and forms no part of the invention.
Vacuum head 4 has walls forming a plenum chamber or vacuum chamber
or suction manifold 27 for exhauster 5, a side wall being
diagrammatically indicated at 28 in FIGS. 4 and 5. The mask plate 8
forms the bottom wall of plenum chamber 27. Plate 8 has a great
multiplicity of airflow orifices formed therein in the form of
relatively long narrow slots 9. A grill or lift plate 10 is secured
to the bottom surface of the plate 8 as by bolts 11.
Grill 10 may have a subway-grating type cellular structure with a
series of cells 12. As shown, grill 10 may be a metal casting
formed with a series of box-like cells 12 having side walls 29 and
end walls 30, many of which are common to adjacent cells 12. Each
cell 12 also has a thick bottom wall 31 and the cell walls 31 are
coextensive in the casting. The upper surface 32 of the cell walls
31 is clamped against the lower surface of mask plate 8 by the
bolts 11.
Each cell 12 is formed with a diamond-shaped opening 33 in its
bottom wall 31 extending between the upper surface 32 and the
shoulder 25 which surrounds opening 33 and extends outward from
opening 33 to cell walls 29 and 30. The face of shoulder 25 in
effect is the lower surface of cell bottom wall 31. Each
diamond-shaped opening is located beneath a slot 9 in mask plate 8
and is slightly longer than slot 9 as well shown in FIGS. 2-6.
Thus, the airflow orifices formed by slots 9 are continued and
enlarged in the diamond-shaped openings 33 in the assembled mask
plate 9 and grill 10. The undersurface of grill 10, that is the
lower edges of cell walls 29 and 30, forms the work-engaging
surface 34 of the vacuum head 4, sometimes referred to as the lift
face.
The improved magnetic valve controls airflow through each orifice 9
and is normally closed (FIG. 4). The magnetic valve includes a
magnetized metal plate 13 which may be a permanent magnet and plate
13 has a larger area than that of slot 9. An actuator 14 preferably
formed of suitable plastic material is connected to plate magnet 13
and extends through slot 9, through diamond-shaped opening 33, and
through cell 12.
Actuator 14 preferably is connected to the plate magnet 13 by an
integral centrally located upwardly disposed stem 15 which extends
through a central opening 16 in plate 13 and through a similar
opening 17 in the sheet metal channel member 18 which preferably
surrounds the top and side edges of the magnetic plate 13 (FIG.
6).
A washer 19 surrounds the upper end of stem 15 and the upper end of
the plastic material stem may be upset or riveted, as indicated at
20, to connect the actuator 14 to the magnetic plate 13.
Upwardly disposed projections 21 are formed at the ends of the
actuator 14 and engage in cavities 22 formed in the underside of
the plate 13 for holding the assembled actuator 14 and plate 13
against relative movement.
An integral depending leg 23 is formed at each end of the actuator
14 and extends below the lift face 34 of grill 10 when the magnetic
valve plate 13 is in closed position as shown in FIG. 4. An
outturned foot 24 is formed at the lower end of each leg 23 which
is adapted to contact grill shoulder 25 to limit opening movement
of the valve as shown in FIG. 5. A depending guide blade 26 is
formed on actuator 14 intermediate the legs 23 and spaced from the
legs. Guide 26 has a greater length than that of the legs 23 so as
to contact a carton 6 when the vacuum head is lowered upon a
carton. Such contact moves actuator 14 to open the valve as shown
in FIG. 5.
Actuator 14 (FIGS. 4, 5 and 6) is not as long in length as slot 9
and has considerably less thickness than the width of slot 9 (FIG.
6) so that when actuator 14 is moved to open position (FIG. 5)
sufficient clearance is present to permit rapid flow of air through
slot 9 around actuator 14 and beneath magnetic plate 13 into plenum
chamber 27 to apply a suction or vacuum lifting force to a carton
contacted by the lift face 34 of vacuum head 4 at each cell 12
defined by cell walls 29 and 30 and the undersurfaces thereof
(FIGS. 4 and 6).
The flow of air also is facilitated when any valve is in open
position by the spaces (FIGS. 4 and 5) between the actuator legs 23
and the guide blade 26. When guide blade 26 is engaged by any
carton 6 to open the valve substantial tilting of any actuator is
limited. For example, tilting in a seesaw manner (FIG. 5) is
prevented by engagement of either of the feet 24 at the ends of
actuator 14 either with the shoulder 25 or the top of the carton 6.
Rotative tilting, viewing FIG. 6, of the actuator 14 again is
limited by the feet 24 engaging shoulder 25 and by one or the other
lower corner of the assembly of magnet 13 and channel member 18
engaging the top of mask plate 8.
This loose mounting permitting free movement of actuator 14 in any
slot 9 and within the cells 12 and diamond-shaped openings 33
avoids the necessity of maintaining close tolerances in the
manufacture of the valve components. The actuator 14 being formed
of plastic material is light in weight. Actuators 14 carry the
weight of the magnetic plates 13 directly on the cartons to be
lifted when the vacuum head 4 is lowered upon a layer of cartons.
Thus the necessity of providing sufficient vacuum to sustain the
load of the movable magnetic valve elements 13 and 14 is
avoided.
Furthermore, there is sufficient flexibility in the plastic
material forming the actuators 14 to permit the legs 23 to be
sprung for inserting an actuator 14 through a slot 9 in the mask
plate 8 for assembling the valves in their airflow slots to be
opened and closed by the valves.
The improved vacuum head magnetic valve construction enables the
head to handle any carton pattern without the necessity of using a
special mask for each pattern. All magnetic valves remain closed
until automatically opened by contact with cartons to be
handled.
Magnetic valves whose actuators are not contacted by cartons will
remain closed, eliminating airflow loss or leakage therethrough.
Those valves which are opened by contact with cartons result in
sealing the lift face of the head against such cartons by the
vacuum airflow through the opened valves.
OPERATION
In the operation of a pallet loader equipped with the improved
magnetic valve construction, when a layer of cartons to be handled
is assembled in the desired pattern at conveyor location 3B, the
carriage 3 is moved on rails 2 in a usual manner until the vacuum
head 4 is located over the layer of cartons, and then the head 4 is
lowered until the magnetic valves are opened by contact of their
actuators 14 with the cartons 6. Meanwhile the exhauster 5 exhausts
air from the vacuum head and plenum chamber and opened valves, and
the grill 10 is sealed against the layer of cartons.
Then, in the usual manner, the vacuum head 4 is raised, and the
carriage 3 is moved upon the rails 2 to a position over a pallet 7,
such as the left-hand pallet in FIG. 1. The vacuum head then is
lowered placing the layer of cartons on the pallet 7, or upon
layers of cartons previously placed thereon, two deposited layers
being shown in FIG. 1.
Airflow suction to the plenum chamber then is cut off and the seal
with the layer of cartons held by the head is broken. As the vacuum
head is raised the layer of cartons remains on the pallet and the
magnetic valves automatically close. The operation may be repeated
until the desired number of cartons have been placed upon a
pallet.
Accordingly, the improved vacuum head magnetic valve construction
provides a universal vacuum head for pallet loaders which is
adapted to handle different package patterns for palletizing the
packages, in which the magnetic valves automatically control the
flow of air providing the lifting force so that contact of the head
with the article to be lifted opens a normally closed valve and
exerts suction on the article to be lifted at a multitude of
locations on the lifting face of the head; provides simple and
efficient magnetic valves which are easy and inexpensive to
manufacture, assemble and operate; and provides a construction
which incorporates the new and advantageous features described,
overcoming the prior art difficulties and solving problems existing
in the art.
In the foregoing description certain terms have been used for
brevity, clearness and understanding, but no unnecessary
limitations are to be implied therefrom beyond the requirements of
the prior art because such terms are used for descriptive purposes
and are intended to be broadly construed.
Moreover, the description and illustration of the invention is by
way of example, and the scope of the invention is not limited to
the exact details shown or described such as the size of the cells,
of the orifice slots, and of the magnetic plates.
Having now described the features, discoveries and principles of
the invention, the manner in which the improved vacuum head
magnetic valve construction is constructed and used in a pallet
loader, the characteristics of the construction, and the
advantageous, new and useful results obtained, the new and useful
structures, devices, elements, arrangements, parts and
combinations, are set forth in the appended claims.
* * * * *