U.S. patent number 3,724,642 [Application Number 05/167,600] was granted by the patent office on 1973-04-03 for accumulator with braking.
This patent grant is currently assigned to Rapistan Incorporated. Invention is credited to Maynard J. De Good.
United States Patent |
3,724,642 |
De Good |
April 3, 1973 |
ACCUMULATOR WITH BRAKING
Abstract
This invention describes a powered roller, accumulator conveyor
having a powered propelling member passing through a plurality of
independent accumulating zones arranged along the conveyor. The
propelling member is shiftable between driving and non-driving
positions with respect to the powered rollers. A brake means
engages the powered rollers to stop their rotation when the
propelling member is shifted to a non-driving position, thereby
preventing movement of articles along the conveyor.
Inventors: |
De Good; Maynard J. (Grand
Rapids, MI) |
Assignee: |
Rapistan Incorporated (Grand
Rapids, MI)
|
Family
ID: |
22608018 |
Appl.
No.: |
05/167,600 |
Filed: |
July 30, 1971 |
Current U.S.
Class: |
198/781.06;
193/35A; 198/781.09 |
Current CPC
Class: |
B65G
47/261 (20130101); B65G 13/075 (20130101) |
Current International
Class: |
B65G
13/00 (20060101); B65g 013/02 () |
Field of
Search: |
;198/127R,160
;193/35A |
References Cited
[Referenced By]
U.S. Patent Documents
|
|
|
3616894 |
November 1971 |
Koenecke et al. |
3621982 |
November 1971 |
Fleischauer et al. |
3225893 |
December 1965 |
Currie |
|
Primary Examiner: Aegerter; Richard E.
Assistant Examiner: Lane; H. S.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows.
1. An accumulator conveyor having a plurality of rollers forming an
article transporting track, a driven propelling member engageable
and disengageable from said rollers; said conveyor having a
plurality of sections arranged in tandem; an article detecting
sensor in each section; support means for said propelling member,
separate and independent actuator means in each section operable on
said support means for bringing together and separating said
rollers and propelling member for effecting drive and nondrive of
said rollers; a brake operatively connected to said actuator means
in each section, said actuator means shifting said brake into
braking engagement with at least one of said rollers in a section
when said actuator means in said section separates the rollers and
propelling member in said section.
2. In an article conveyor having transport rollers, support
rollers, a propelling member located between said transport and
support rollers for driving said transport rollers and means for
shifting said propelling member between driving and non-driving
positions, the improvement comprising: said shifting means
including inflatable actuator means on said conveyor for shifting
said support rollers and said propelling member between said
positions; brake means on said conveyor operatively connected to
said shifting means, said brake means including engaging means
operable against at least one of said transport rollers when said
propelling member is shifted to a non-driving position to thereby
prevent the movement of articles along said conveyor by preventing
rotation of said transport rollers.
3. A conveyor as described in claim 2 and further including means
biasing said engaging means into transport roller engaging
position, said shifting means urging said brake away from said
engaging position when said propelling member is in driving
position.
4. The conveyor as described in claim 3 wherein said brake is an
arm-like member pivotally mounted along its length on said
conveyor, said member having said engaging means fixed at one of
its ends and said biasing means is connected to the other of its
ends.
5. The conveyor brake mechanism as described in claim 4, wherein
said shifting means includes said support rollers, a shaft mounting
said rollers for rotation, said actuator operable against said
shaft to move said propelling member into and out of engagement
with said transport rollers wherein said brake is operated by
movement of said shaft against said arm at a point between said
pivotal mounting and said biasing means.
6. A conveyor as described in claim 4 wherein said biasing means is
a spring connected at one of its ends to said conveyor and at its
other end to said other end of said arm.
7. In an article conveyor having transport rollers; a propelling
member for driving said transport rollers; vertically shiftable
support rollers supporting said propelling member, said support
rollers each having a shaft extending from the ends thereof; means
operating on said shaft for shifting said support rollers and said
propelling member between driving and non-driving positions; and
brake means on said conveyor operable against at least one of said
transport rollers when said support rollers and said propelling
member are shifted to a non-driving position; and brake means
comprising:
an elongated arm member having opposed ends;
pivot mounting means between said opposed ends mounting said arm
member on said conveyor;
friction means on one of said ends of said arm, said friction means
adapted to engage said one of said transport rollers;
biasing means on the other of said ends of said arm, said biasing
means urging said arm to pivot about said pivot mounting means for
shifting said friction means into engagement with said one of said
transport rollers; and
said shaft operatively engaging said arm member between said pivot
mounting means and said other end to urge said arm to pivot about
said pivot mounting means and shift said friction means out of
engagement with said one of said transport rollers when said
propelling member is shifted into driving position.
Description
BACKGROUND OF INVENTION conveyors
This invention relates to accumulator conveyor and more
particularly to an accumulator conveyor in which delivery or
non-delivery of the propelling force to the article is
pneumatically controlled. The invention constitutes an improvement
over accumulator conveyors of the type shown, for example, in
United States Pat. No. 3,420,355, M.J. De Good et al., issued Jan.
7, 1969.
The improvement of this invention lies in the fact that the
conveyor utilizes compact, lightweight, simple and relatively
inexpensive pneumatic means to control the movement of articles
along its track. Because of the pneumatic operation it inherently
provides a time delay feature between the sensing of an article and
the response of the article movement control means. A further
improvement lies in the provision of an override feature which
permits instantaneous actuation of all operating zones regardless
of the position of the sensors to effect rapid and complete
clearing of the entire conveyor.
These and other objects and advantages of this invention will be
readily understood by those skilled in the conveyor art upon
reading the following specification and the accompanying drawings
in which:
FIG. 1 is a top plan view of a roller conveyor incorporating this
invention;
FIG. 2 is a side elevational view of the conveyor shown in FIG.
1;
FIG. 3 is a sectional elevation view taken along the plane III--III
of FIG. 2;
FIG. 4 is a sectional elevational view taken along the plane IV--IV
of FIG. 3;
FIG. 5 is a sectional elevational view taken along the plane V--V
of FIG. 3;
FIG. 6 is a sectional elevation view similar to FIG. 3 showing the
conveyor in a non-article propelling position;
FIG. 7 is an enlarged elevational view similar to FIG. 2 with
portions broken away to illustrate the sensing mechanism of the
invention;
FIG. 8 is a view like FIG. 7 illustrating the brake mechanism of
the invention;
FIG. 9 is a pneumatic control schematic illustrating the basic
pneumatic pressure system of this invention;
FIG. 10 illustrates a pneumatic control schematic of the transport
override and rapid clearing feature of this invention; and
FIG. 11 is a diagrammatic view of an accumulator conveyor showing
the placement of the actuators along the length of the
conveyor.
In executing this invention, vertically shiftable supporting
rollers for the propelling member are arranged in groups, each
group being operated by a pneumatically powered actuator. The
assembly is biased downwardly into a position in which the
propelling member is out of article propelling position. When fluid
pressure is admitted to the actuator, the bias is overcome, and the
actuator shifts the support rollers upwardly into a position in
which the propelling member is in an article propelling
position.
An article detecting sensor operates a valve interposed between the
actuator and the source of fluid pressure. In an article propelling
position, the actuator is energized by the fluid pressure source
through the valve. Upon the sensing of an article, the valve closes
with respect to the pressure source and opens with respect to the
actuator releasing the pressure therein and allowing the support
rollers and propelling means to shift to an article non-propelling
position.
A pivotally mounted brake mechanism connected to the actuator and
operable against selected transport rollers is also provided to
positively retard and stop the movement of articles on the
conveyor.
Referring specifically to FIGS. 1 and 2 of the drawings, the
numeral 10 indicates a conveyor track of conventional design having
a pair of side rails 12 and 13 and article supporting rollers 14 at
spaced intervals therebetween forming an article supporting and
conveying surface. An endless propelling member or belt 16 is
located below the transport rollers 14. It will be recognized that
the propelling member passes over terminal pulleys at each end of
the run and has some type of conventional equipment to drive it.
This equipment is not illustrated inasmuch as it is conventional in
design, and many types of equipment are available for that
purpose.
The belt 16 is supported for engagement with the transport rollers
by support or pressure rollers 18. Each of the support rollers is
rotatably mounted on a shaft 20. The rollers are supported at one
end by the shaft 20 in a slot 22 (FIG. 3) formed in the side rail
12. The opposite ends of the pressure rollers are supported by the
shaft on an interior support rail 24 (FIG. 3). The interior support
rail 24 is provided with a plurality of equally spaced elongated
openings 26 which receive the pressure roller shaft 20. The
openings 26 extend vertically in the interior support rail allowing
vertical movement of the shaft therein. The interior support rail
24 illustrated in greater detail in FIG. 3 is generally formed as a
channel 28 partially closed at the top on the side opposite the
openings 26. The channel 28 runs parallel to and is fixed to the
inside of the side rail 12 such that the openings 26 are in
alignment with the slots 22 in the opposite side rail 13.
An inflatable elongated tube-like member 30 is positioned inside
the channel 28 and in its inflated position holds the pressure
rollers in an upward or article propelling position. As
illustrated, this is accomplished by means of a flat support plate
32 positioned inside the closed channel 28. When the tube is
inflated, the support plate 32 is urged upwardly against the shafts
22 moving them upwardly within the confines of the slots 26. The
shafts 22 on one side and the inwardly turned lip 34 on the
opposite side of the closed channel confine the plate 32 and
prevent it from moving out of the channel when the tube is
inflated.
The tube-like member 30 illustrated in FIG. 4, may be made of a
fabric reinforced noeprene rubber. The member is closed at one of
its ends 36 in any convenient fashion such as by vulcanizing. The
opposite end 38 is similarly closed and is provided with an inlet
tube or fitting 40 which is connected by means of suitable tubing
42 through an actuator control valve 44 to a source of fluid
pressure.
A plurality of article sensing assemblies 46 are positioned along
the length of the conveyor 10 at predetermined intervals and
provide the control means for each of the accumulating zones.
Referring to FIGS. 2, 3 and 7, each sensor assembly 46 comprises a
pair of spaced apart bracket members 48 and 50 mounted on pivot
pins 54 which are fixed to the side rails 12 and 13 of the
conveyor. At their upper ends, the brackets 48 and 50 are provided
with hex holes 52 (FIGS. 2 and 7) for engagement with the shaft 55
of a sensor roller 49. In its sensing position, the roller 49 is
supported slightly above the level of the transport rollers 14 of
the conveyor surface. The brackets extend downwardly from the
roller. In the case of the bracket 50 on the side 12 of the
conveyor having the interior support rail 24, the bracket curves
inwardly to allow clearance for the support rail and actuator
mechanism. The brackets are connected together by means of a tube
56 fixed at each of its ends to the lower ends of the brackets 48
and 50. The brackets 48 and 50, the tube 56, and the sensing roller
49 on its shaft 54 move together and form an integral sensing
assembly 46. Bracket 54 is provided with an outwardly turned flange
58 which is adapted to threadably receive an adjustment screw 60.
The length of the screw 60 may be adjusted for engagement with the
plunger 66 of the actuator control valve 44 which will be more
fully described hereinafter.
A resilient bias spring 62 is fixed at one end 64 to the conveyor
side rails 12 and at its other end to the bracket 48. The spring 62
biases the sensor assembly 46 into an upper or sensing position.
The upper limit of travel of the sensor roller is established by
the adjustment screw 60 moving against the plunger 66 of the valve
44.
The actuator control valve 44 controls the fluid pressure supply to
the pneumatic actuator 30 and also, in response to an input from
the sensor, closes the input from the fluid supply source and vents
the pressure in the actuator to the atmosphere. In an article
propelling position, the valve is open with respect to the fluid
pressure source and closed with respect to the atmosphere to
thereby apply the source of pressure directly to the pneumatic
actuator 30.
Referring now to FIG. 5, the valve assembly 44 is seen to comprise
a main body portion 70 having mounting holes 72 therein for
mounting on a downwardly extending flange 25 of the interior
support wall 24 by means of conventional fastening means 27. (FIGS.
3, 6 and 7).
The main body 70 of the valve is provided with a pair of
communicating passageways 80 and 90. The first opening or
passageway 80 extends along the length of body 70 and is tapered
outwardly and undercut at one end to form an internal valve seat
82. The inlet to the valve seat 82 has a diameter slightly larger
than that of the valve seat 82 and is threaded to receive an inlet
fitting 74 provided for connection to a source of fluid pressure.
An "O" ring 84, a spherical bearing or ball valve 86 and a bias
spring 88 are positioned within the enlarged portion of the opening
80. The "O" ring 84 is placed in the undercut groove and forms a
resilient seat surface for the ball valve 86 when it is urged
forwardly (to the left as viewed in FIG. 5) by the bias spring 88.
As illustrated in the figure, the valve is closed with respect to
the fluid pressure source which enters through the fitting 74.
A primary outlet 90 in the valve extends transversely of the
opening 80 and opens through a side wall of the body 70. The
primary outlet 90 is threaded at an enlarged end to receive a
fitting 76 which may be connected by means of tubing 42 (FIGS. 3
and 6) to the pneumatic actuator 30. A piston control assembly 66
is slidably positioned in the opening 80 opposite the inlet end.
The piston is provided with an enlarged head portion 94 and an
extending reduced reduced diameter shank portion 99. When the
piston is positioned in the opening 80, the shank portion 99
extends along the length of the opening 80 to control the ball
valve 86 as will be more fully described hereinafter. The shank is
provided with a pair of spaced-apart enlarged diameter portions 92
and 93 positioned below the head and midway along the length of the
shank respectively. The outer diameter of these enlarged portions
is slightly less than that of the passageway 80 through which they
pass. A screw 89 (shown in dotted lines) is threaded into the body
70 and extends into the opening 80 between the enlarged diameter
portions 92 and 93. This prevents the piston from being pushed out
of the opening 80 by the force of the pressure. The piston head 94
is provided for engagement with the adjusting screw 48 on the
sensor bracket 50 (FIG. 2). An "O" ring 96 surrounds the enlarged
portion 92 of the piston body adjacent the head and forms (when the
piston is moved to the right) a pressure-tight seal between the
head of the piston and the housing 70. The space between the outer
diameter of the integral portions 92 and 93 and the diameter of the
opening 80 provides a secondary outlet port 98 for fluid
pressure.
As illustrated in the figure, the valve is in a position as would
be obtained by the presence of an article on the sensor, that is,
the bracket as shown in FIG. 2 and 7, is moved away from the valve,
and the fluid pressure is being exhausted from the actuator to the
atmosphere through the secondary outlet port 98. Fluid pressure
from the actuator 30 flows back through the fitting 76, the opening
90, and through the opening 80 along the sides of the enlarged
diameter portion of piston 92 and 93 where it is vented to the
atmosphere between the enlarged diameter portion 92 at the
secondary outlet port 98. In this position, the flow of pressure
from the source is effectively blocked by the ball valve 86 which
is held against the valve seat by the bias spring 88 and the force
of the pressure itself.
When the conveyor is in an article-propelling position, the sensor
46 is in its biased upwardly position and the fluid pressure is
admitted to the actuator 30 through the valve 44 in the following
matter. The bias spring 64 urges the sensor roller 49 upwardly with
the sensing assembly 46 and the adjustment screw 66 on bracket 50
presses against the head of the valve 94 moving the piston assembly
66 as shown in FIG. 5 to the right. As the piston is moved to the
right, the end of the shank 99 of piston 66 moves through the area
of the valve seat 82 and displaces the ball valve 86 by compressing
spring 88. At the same time, the "O" ring 96 positioned below the
head 94 around the piston body 92 is compressed between the head 94
and valve body 70 closing the secondary outlet port 98. The fluid
pressure from the source is then allowed to flow through inlet
fitting 74 through ports 80 and 90 and fitting 76 to the pneumatic
actuator 30 causing it to inflate and position the support rollers
in an article propelling position.
A conveyor having a plurality of independent operating zones
designated A through E is schematically illustrated in FIG. 11. As
will be readily understood by those skilled in the art, each zone
is controlled by a sensor assembly which operates to control the
drive means for each zone. Normally, the sensing rollers for one
zone are located adjacent to the discharge end of the next adjacent
zone downstream of the conveyor in the direction of article
movement. An article coming to rest on a sensor in a first zone
shifts the upstream actuator to a non-propelling position and so on
along the conveyor. To provide proper centering of the drive belt
16 along the length of the conveyor, it has been found desirable to
alternate the location of each actuator mechanism 30 along the
length of the conveyor. The actuator mechanism for each adjacent
zone may be positioned on opposite sides of the conveyor. Zones A,
C and E may be positioned adjacent side rail 12 while zones B and D
may be positioned adjacent side rail 13. In this manner, as the
belt is moved to a non-driving position as illustrated in FIG. 3,
the belt 16 in the next zone will tilt in the opposite direction
thereby preventing any tendency of the belt to shift to one side of
the conveyor.
Because of inertia articles will often continue moving along the
conveyor even after the drive means has been shifted into an
article non-propelling position. To prevent this occurrence it is
desirable to provide a brake means at each zone.
The brake mechanism illustrated in FIGS. 2 and 8 is generally
indicated by the numeral 100. The brake is essentially an elongated
arm-like member 102 pivotally mounted on the interior support rail
24 by conventional fastening means to form a pivot point 104. One
end of the arm is bent outwardly to form a flange 106 to hold a
friction pad 108 which in one position engages a transport roller
14 positioned thereabove. Bias spring 110 is connected to the
opposite end 112 of the arm and to the supporting framework of the
conveyor 10. When the actuator pressure is released, the support
rollers are lowered to a non-propelling position; and the bias
spring 110 causes the arm to pivot around the pivot point 104
thereby bringing the friction pads into engagement with the
transport rollers. The brake responds to dropping of the pressure
rollers to retard or stop the movement of articles on the conveyor.
Movement of the brake is controlled with movement of the actuator
30 in response to an input from the sensor 46. The arm 102 of the
brake 100 is supported on a shaft 20 of a pressure roller 18 at a
point midway between the pivot point 104 and the end 112 connected
to the bias spring 110. As the pressure roller 18 is moved on its
shaft 20 within the slot 22 in response to movement of the
actuator, a corresponding and opposite movement takes place in the
brake arm. As the pressure rollers are shifted to an article
non-propelling position, the end 112 of the arm is moved downwardly
with the shaft by the bias spring 110 thereby causing the friction
pad 108 to contact the transport roller located thereabove to stop
its movement. A plurality of brake members are normally provided in
each operating zone of the conveyor. Ideally, one brake will be
operated by each pressure roller to control every other transport
roller on the conveyor.
In normal operation of the conveyor, the articles thereon will move
along the conveyor until at some point, the article movement is
stopped by a controlled gate (not shown) or other article movement
preventing mechanism. At that time, articles accumulate until the
sensor is activated thereby shifting the adjoining accumulating
zone into an article non-propelling position. The articles will
accumulate in that zone and actuate its associated sensor and so on
along the conveyor. When articles move along the conveyor from zone
to zone without accumulating, they naturally pass over and trip the
various sensors. This, however, has no effect on the actuator or
pressure valve as there is an inherent time delay built into the
valve. The rate at which the pressure is vented to the atmosphere
is controlled by the difference in diameter between the passage 80
and the enlarged diameter portions 92 and 93 on the valve shank
(FIG. 5). By the time the pressure has started to vent from the
actuator to the atmosphere through the secondary outlet the article
will have passed the sensor and pressure will again be applied from
the source to the actuator.
When conveyors are operated at high speed, the inherent time delay
of valve 44 may be excessive and it will become necessary to
provide an auxiliary rapid exhaust valve. FIG. 9 schematically
illustrates a pneumatic pressure system of this invention wherein
the actuator 30 is connected to the valve 44 through a quick
release exhaust valve 120. The valve 44 is connected to a source of
fluid pressure 122 by line 124. The valve schematically illustrated
is identical to that previously disclosed in connection with FIG. 5
with the reference numerals 74, 90, and 98 representing the input,
the primary outlet, and the secondary outlet respectively.
The primary outlet 90 from the valve is connected via line 126
through an exhaust valve 120 through line 128 to the actuator 30.
The quick release or exhaust valve 120 is a three-way valve of
conventional construction having an exhaust port 130. The valve is
normally biased to a closed position with respect to the input
through line 126 from the valve 44 while the exhaust port 130 is
normally opened allowing the pressure in actuator to vent to the
atmosphere through line 128 and exhaust port 130. When valve 44 is
opened, the passage of fluid pressure through line 126 overcomes
the bias on valve 120 thereby allowing fluid pressure to pass
through line 128 to the actuator. At the same time, the exhaust
port 130 of the valve 120 is closed. Upon sensing of an article on
the conveyor, the valve 44 closes in the manner previously
described thereby blocking the fluid pressure supply and venting
the outlet port 90 to the atmosphere through the secondary outlet
98. Exhaust valve 120 rapidly closes and the pressure in the
actuator 30 is vented to the atmosphere through line 128 and the
exhaust port 130.
Often it becomes necessary to provide a means for rapidly clearing
the conveyor surface. This is readily accomplished by
simultaneously applying a fluid pressure to each of the pneumatic
actuators along the conveyor thereby causing the pressure rollers
in each of the zones to move to an article propelling position.
This system is illustrated in schematic form in FIG. 10. As
contrasted to the illustration of FIG. 8, the novel rapid clearing
or transport override system requires the addition of a manually
controlled valve 131 connected to the source 122 and a normally
closed check valve 132 connected in parallel to each of the sensor
actuated valves 44 at its outlet end. The manually controlled valve
131 is connected at its inlet end to the source of fluid pressure
by line 134. The outlet of the valve is connected to the check
valve 132 by means of line 136. One check valve is provided for
each actuator and connected thereto on the primary outlet side 90
of the valve 44. The check valves are installed so that in a normal
operating position there is no pressure flow from the outlet side
90 of valve 44 into line 136. When it is desired to clear the
conveyor, valve 131 is opened and the fluid pressure from the
source is applied through the check valve directly to the actuator
without regard to the position of valve 44. In this manner, all
actuators connected through check valves to line 136 will be moved
to their raised position thereby shifting the drive means into an
article propelling position in all zones simultaneously. A slight
back flow of pressure occurs from line 136 into valve 44 through
line 126 to secondary outlet 98. This is of no consequency,
however, as the rate at which the pressure is vented to the
atmosphere is much less than the input from line 136. When the
articles have cleared the conveyor, valve 131 may be closed and the
actuators will begin operating in the previously described normal
fashion.
This rapid clearing feature also increases the versatility of the
conveyor as by simply placing the valve 131 in an open position all
of the actuators in each zone are energized and the conveyor will
operate as a conventional powered roller conveyor.
From the foregoing description and drawings, it will be readily
apparent to those skilled in the art that the present invention
provides an extremely versatile conveyor utilizing relatively
simple and inexpensive component parts and which may be readily
adapted for use as a conventional powered conveyor.
While several embodiments of this invention have been illustrated
and described, it will be recognized that other embodiments and
modifications of this invention incorporating the teachings hereof
may be readily made in light of this disclosure. All modifications
embodying the principles of this invention are to be considered as
included in the appended claims unless these claims by their
language expressly state otherwise.
* * * * *