U.S. patent application number 14/163471 was filed with the patent office on 2014-07-31 for film tension apparatus and supply roll support for stretch wrapping machines.
This patent application is currently assigned to LANTECH.COM, LLC. The applicant listed for this patent is LANTECH.COM, LLC. Invention is credited to Daniel R. Hendren, Robert D. Janes, Patrick R. Lancaster, III, Curtis W. Martin, Thomas E. Phillips.
Application Number | 20140208696 14/163471 |
Document ID | / |
Family ID | 51221420 |
Filed Date | 2014-07-31 |
United States Patent
Application |
20140208696 |
Kind Code |
A1 |
Phillips; Thomas E. ; et
al. |
July 31, 2014 |
Film Tension Apparatus And Supply Roll Support For Stretch Wrapping
Machines
Abstract
A film dispenser for stretch wrapping machines includes at least
one roller and a first brake engageable with a braking surface the
one roller. The first brake may include a flat brake pad that is
pivotally movable for engagement with the braking surface, and is
adjustable between a first configuration engaged with the braking
surface and applying a first braking force, and a second
configuration disengaged from the braking surface or only minimally
engaged with the braking surface such that any braking force
applied is substantially less than the first braking force.
Inventors: |
Phillips; Thomas E.;
(Louisville, KY) ; Hendren; Daniel R.; (Mount
Washington, KY) ; Janes; Robert D.; (Louisville,
KY) ; Lancaster, III; Patrick R.; (Louisville,
KY) ; Martin; Curtis W.; (Georgetown, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LANTECH.COM, LLC |
Louisville |
KY |
US |
|
|
Assignee: |
LANTECH.COM, LLC
Louisville
KY
|
Family ID: |
51221420 |
Appl. No.: |
14/163471 |
Filed: |
January 24, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61756710 |
Jan 25, 2013 |
|
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|
61787657 |
Mar 15, 2013 |
|
|
|
61794479 |
Mar 15, 2013 |
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61856272 |
Jul 19, 2013 |
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Current U.S.
Class: |
53/461 ;
53/203 |
Current CPC
Class: |
B65B 41/12 20130101;
B65H 2555/13 20130101; B65H 23/08 20130101; B65H 2801/81 20130101;
B65B 11/045 20130101 |
Class at
Publication: |
53/461 ;
53/203 |
International
Class: |
B65B 11/04 20060101
B65B011/04 |
Claims
1. A film dispenser for stretch wrapping machines, comprising: at
least one roller, the roller having a longitudinal axis and a
circumferential film engaging surface; a braking surface extending
circumferentially around the roller relative to the circumferential
film engaging surface; and an electrically-actuated first brake
engageable with either a portion of a sector of the braking surface
or a portion of an area defined by an arc along the braking surface
of the at least one roller, the first brake selectively adjustable
between a first configuration engaged with the braking surface and
applying a first braking force to the braking surface, and a second
configuration wherein the first brake is disengaged from the
braking surface or is only minimally engaged such that any braking
force applied is substantially less than the first braking
force.
2. The film dispenser of claim 1, further comprising: a disk
coupled with a first axial end of the at least one roller, the disk
having first and second oppositely disposed sides; wherein the
braking surface is located on circumferentially extending portions
of the first and second sides of the disk.
3. The film dispenser of claim 2, wherein the first brake comprises
a first brake pad adjacent the first side of the disk and a second
brake pad adjacent the second side of the disk, such that the disk
is disposed between the first and second brake pads; at least one
of the first and second brake pads movable between the first and
second configurations of the first brake along directions
substantially parallel to an axial direction of the disk.
4. The film dispenser of claim 2, wherein the first brake is
selectively adjustable to vary the amount of first braking force
applied to the braking surface.
5. The film dispenser of claim 3, wherein the first brake comprises
an actuator operatively coupled with the first brake pad, the
actuator selectively actuatable to at least a first condition
wherein the first and second brake pads engage the braking surface
in the first configuration of the first brake, and wherein the
first braking force stretches the film material during wrapping of
a load.
6. The film dispenser of claim 5, wherein the actuator is
actuatable to a second condition wherein the first and second brake
pads engage the braking surface in the first configuration of the
first brake, and wherein the first brake applies a second braking
force that prevents free rolling of the roller while allowing the
roller to rotate to facilitate threading of film through the
dispenser.
7. The film dispenser of claim 6, wherein the actuator is
actuatable to a third condition wherein the first and second brake
pads engage the braking surface in the first configuration of the
first brake, and wherein the first brake applies a third braking
force that locks the roller against rotation.
8. The film dispenser of claim 7, wherein the actuator is
actuatable to a fourth condition wherein at least the first brake
pad is disengaged from the braking surface in the second
configuration of the first brake.
9. The film dispenser of claim 5, further comprising: a first brake
arm pivotally movable about a first pivot axis that is
substantially perpendicular to the axial direction of the disk; the
first brake pad supported on the first brake arm for pivotal
movement about the first pivot axis into engagement with the
braking surface.
10. The film dispenser of claim 9, further comprising: a second
brake arm pivotally movable about a second pivot axis that is
substantially perpendicular to the axial direction of the disk; the
second brake pad supported on the second brake arm for pivotal
movement about the second pivot axis into engagement with the
braking surface.
11. The film dispenser of claim 10, wherein the roller is
resiliently supported for movement in a direction along the
longitudinal axis of the roller and biased in a direction toward
the disk to compensate for the weight of the roller.
12. The film dispenser of claim 1, wherein the first brake
comprises a solenoid actuator having an armature operatively
coupled with a first brake pad, the armature moving the first brake
pad to engage the braking surface in the first configuration of the
first brake.
13. The film dispenser of claim 12, wherein the solenoid actuator
is selectively actuatable to at least a first condition wherein the
first brake pad engages the braking surface in the first
configuration of the first brake, and wherein the first braking
force stretches the film material during wrapping of a load.
14. The film dispenser of claim 13, wherein the solenoid actuator
is actuatable to a second condition wherein the first brake pad
engages the braking surface in the first configuration of the first
brake, and wherein the first brake applies a second braking force
that prevents free rolling of the roller while allowing the roller
to rotate to facilitate threading of film through the
dispenser.
15. The film dispenser of claim 14, wherein the solenoid actuator
is actuatable to a third condition wherein the first brake pad
engages the braking surface in the first configuration of the first
brake, and wherein the first brake applies a third braking force
that locks the roller against rotation.
16. The film dispenser of claim 15, wherein the solenoid actuator
is actuatable to a fourth condition wherein the first brake pad is
disengaged from the braking surface in the second configuration of
the first brake.
17. A film dispenser for stretch wrapping machines, comprising: at
least one roller, the roller having a circumferential film engaging
surface and a circumferential braking surface; a brake arm
pivotally movable about a pivot axis spaced from the roller; a
brake pad supported on the brake arm for pivotal movement with the
brake arm about the pivot axis into engagement with the braking
surface along a substantially radial direction of the roller; and
an actuator operatively engaging the brake arm at a location spaced
from the pivot axis and the brake pad, whereby braking force
applied by the brake pad when the actuator is actuated is increased
by leverage of the brake arm about the pivot axis.
18. The film dispenser of claim 17, wherein the actuator
selectively actuatable to at least one of: a first condition
wherein the brake pad engages the braking surface with a first
braking force that stretches the film material during wrapping of a
load. a second condition wherein the brake pad engages the braking
surface with a second braking force that prevents free rolling of
the roller while allowing the roller to rotate to facilitate
threading of film through the dispenser; a third condition wherein
the brake pad engages the braking surface with a third braking
force that locks the roller against rotation; or a fourth condition
wherein the brake pad is disengaged from the braking surface.
19. A method of dispensing stretch wrap material to a load, the
method comprising: feeding film from a supply roll; engaging the
film from the supply roll with at least one roller; selectively
engaging the roller with a first brake; and engaging the roller
with a second brake.
20. The method of claim 19, further comprising applying at least
one of: a first braking force to the roller with the first brake
such that the film is stretched as it is applied to wrap the load;
a second braking force to the roller with the second brake, the
second braking force preventing prevent free rolling of the roller
while allowing the roller to rotate sufficiently to facilitate
threading film from the supply roll to the roller when the first
brake is not engaged; or a third braking force to the roller with
the first brake such that the roller is locked against rotation.
Description
CROSS-REFERENCE
[0001] This application claims the benefit of U.S. Provisional
Patent Application Ser. No. 61/756,710 filed Jan. 25, 2013
(pending); U.S. Provisional Patent Application Ser. No. 61/787,657
filed Mar. 15, 2013 (pending); U.S. Provisional Patent Application
Ser. No. 61/791,479 filed Mar. 15, 2013 (pending); and U.S.
Provisional Patent Application Ser. No. 61/856,272 filed Jul. 19,
2013 (pending). The disclosures of which are expressly incorporated
by reference herein in their entirety.
TECHNICAL FIELD
[0002] The present invention relates generally to stretch wrapping
loads and, more particularly, to improved methods and apparatus for
applying film tension and supporting a film supply roll in stretch
wrapping machines.
BACKGROUND
[0003] Various packaging techniques have been used to assemble a
load of unit products and subsequently wrap them for
transportation, storage, containment and stabilization, protection
and waterproofing. Products are often stacked as a load on a pallet
to simplify handling of the products. The pallet load is commonly
wrapped with stretch wrap packaging material. One system uses
stretch wrapping machines to stretch, dispense, and wrap stretch
packaging material around a load. Stretch wrapping can be performed
as an inline, automated packaging technique that dispenses and
wraps packaging material in a stretched condition around a load on
a pallet to cover and contain the load. Pallet stretch wrapping,
whether accomplished by a turntable, a rotating arm, or by a
vertically movable rotating ring, typically covers the vertical
sides of the load with a stretchable film, such as polyethylene
film. In each of these arrangements, relative rotation is provided
between the load and the packaging material dispenser to wrap
packaging material around the sides of the load.
[0004] It is generally desirable to stretch the film material prior
to wrapping the load. In some machines, pre-stretching of the film
is accomplished by first and second pre-stretch rollers that rotate
at different speeds so that film material passing between the two
rollers is stretched prior to application to a load. In other
machines, pre-stretching of the film may be accomplished by
applying braking forces to a film web extending between a supply
roll and the load.
[0005] Previous methods and apparatus for stretching film material
through the application of braking forces have been unsatisfactory.
For example, difficulties have been experienced controlling the
braking force on a tension roller that stretches film between a
supply roll and a load. These variations may be caused by
fluctuations in forces in the film web due to the geometry of the
load as the film web is being applied by relative rotation between
the load and the film dispenser. Oscillation of the film supply
roll on a support post may also cause force variations in the film
web. These force variations can occur at different wrapping speeds
due to the gradual reduction in the mass of the film roll as film
is used up. Other force variations may result from the engagement
between a brake pad used to apply a braking force to the tension
roller as film is applied to a load.
[0006] Accordingly, there is a need for improved methods and
apparatus for overcoming these and other drawbacks of conventional
stretch wrapping machines.
SUMMARY
[0007] The present invention overcomes the foregoing and other
shortcomings and drawbacks of apparatus and methods heretofore
known for use in stretch wrapping loads. While the invention will
be described in connection with certain embodiments, it will be
understood that the invention is not limited to these embodiments.
On the contrary, the invention includes all alternatives,
modifications and equivalents as may be included within the spirit
and scope of the present invention.
[0008] According to one aspect of the present disclosure, a film
dispenser for stretch wrapping machines includes at least one
roller and a first brake engageable with a braking surface the one
roller. The first brake is adjustable between a first configuration
engaged with the braking surface and applying a first braking force
to the braking surface, and a second configuration disengaged from
the braking surface or only minimally engaged with the braking
surface such that any braking force applied is substantially less
than the first braking force. In one embodiment, the first brake
may be an electrically-actuated brake. In another embodiment, the
first brake may include a flat brake pad that is pivotally movable
about a pivot axis spaced from the roller such that the brake pad
is movable into engagement with the braking surface generally along
a radial direction of the roller.
[0009] In another aspect, a supply roll support for a film
dispenser includes an elongate post sized to receive a roll of film
thereon, and a pliable sheet coupled with the outer peripheral
surface of the post and extending around at least a portion of the
outer peripheral surface. At least a portion of the pliable sheet
is spaced radially outwardly from the outer peripheral surface for
engagement with the inner diameter of a supply roll supported on
the post.
[0010] The above and other objects and advantages of the present
invention shall be made apparent from the accompanying drawings and
the description thereof.
[0011] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory and are intended to provide further explanation of
the disclosure as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate embodiments of
the invention and, together with the general description of the
invention given above, and the detailed description given below,
serve to explain the principles of the invention.
[0013] FIG. 1 is a perspective view of an exemplary stretch
wrapping machine in accordance with the principles of the present
invention.
[0014] FIG. 2 is an exploded perspective view of an exemplary
dispenser of the stretch wrapping machine of FIG. 1, illustrating
an exemplary brake assembly and an exemplary film roll post in
accordance with the principles of the present invention.
[0015] FIG. 3 is a perspective view of an exemplary brake assembly
of the dispenser of FIG. 2.
[0016] FIG. 4A is a cross-sectional view of the brake assembly of
FIG. 3, taken along line 4A-4A.
[0017] FIG. 4B is a cross-sectional view of the brake assembly,
similar to FIG. 4A, illustrating operation of the brake assembly
with increased preload.
[0018] FIG. 4C is a cross-sectional view of the brake assembly,
similar to FIG. 4A, illustrating disengagement of the brake
pad.
[0019] FIG. 5 is a partial top view of the brake assembly of FIG.
4C, taken along line 5-5.
[0020] FIG. 6A is a schematic illustration of the dispenser of FIG.
2, illustrating an exemplary path of film material through the
dispenser.
[0021] FIG. 6B is a schematic illustration similar to FIG. 6A,
illustrating an alternative film path through the dispenser.
[0022] FIG. 7 is a perspective view of a second exemplary brake
assembly in accordance with the principles of the present
invention.
[0023] FIG. 8 is a top plan view of the brake assembly of FIG.
7.
[0024] FIG. 9 depicts a perspective view of a third exemplary brake
assembly in accordance with the principles of the present
invention.
[0025] FIG. 10A is a side elevation view of the brake assembly of
FIG. 9.
[0026] FIG. 10B is a side elevation view similar to FIG. 10A,
depicting the brake assembly of FIG. 9 in an engaged condition.
[0027] FIG. 11 is a perspective view of a fourth exemplary brake
assembly in accordance with the principles of the present
invention.
[0028] FIG. 12A is a side elevation view of the brake assembly of
FIG. 11.
[0029] FIG. 12B is a side elevation view similar to FIG. 12A,
depicting the brake assembly of FIG. 11 in an engaged
condition.
[0030] FIG. 13 is an enlarged detail view of the bottom of the
tension roller of the brake assembly of FIG. 11.
DETAILED DESCRIPTION
[0031] FIG. 1 depicts an exemplary stretch wrapping machine 10
including a film dispenser 12 for applying pre-stretched film
material 14 to a load 16 from a supply roll 18. The dispenser 12 is
coupled to a vertically extending mast 20. During wrapping of the
load 16, the dispenser 12 moves up and down the mast 20 while
paying out film material 14 so that the film material 14 is
spirally wrapped around the load 16. The stretch wrapping machine
10 further includes a load support 22 having a turntable 24 for
rotating the load 16 supported thereon relative to the dispenser 12
during wrapping of the load 16.
[0032] FIG. 2 is an exploded perspective view of the exemplary film
dispenser 12 of FIG. 1. The film dispenser 12 includes a bottom
plate 30 supporting the components of the dispenser 12, and a
supply roll post 32 coupled with the bottom plate 30. The dispenser
12 further includes first and second guide rollers 34, 36 supported
in journal bearings 38 coupled between the bottom plate 30 and a
top plate 40 spaced from the bottom plate 30. The dispenser 12
further includes a brake assembly 42 supported on the top plate 40
and enclosed by a removable cover 44. A tension roller 46 extends
between the bottom plate 30 and a bearing plate 48 secured to the
top plate 40. The tension roller 46 includes a circumferentially
extending film engaging surface 50 that contacts film material 14
dispensed from the supply roll 18, and a circumferential braking
surface 52 (see FIG. 4A).
[0033] With continued reference to FIG. 2, and referring further to
FIGS. 1, 6A, and 6B, film material 14 from the supply roll 18 is
directed along a film path around one or more of the guide rollers
34, 36 and around the tension roller 46 before being directed
toward a load 16 on the turntable 24 for winding upon the load 16.
FIGS. 6A and 6B illustrate two exemplary paths for threading film
material 14 through the dispenser 12 for application to a load 16.
In FIG. 6A, the supply roll 18 has been placed over the support
post 32 such that film material 14 is dispensed by rotation of the
supply roll 18 in a clockwise direction about the support post 32.
In FIG. 6B, the supply roll 18 has been placed over the support
post 32 such that film material 14 is dispensed from the supply
roll 18 during counterclockwise rotation of the supply roll 18
about the support post 32. The tension roller 46 may be coated with
a friction material 54 (see FIG. 4A) in the region of the film
engaging surface 50 to increase friction between the tension roller
46 and the film material 14, or to prevent slipping of the film
material 14 circumferentially around the tension roller 46.
[0034] Referring now to FIGS. 3, 4A, and 5, the brake assembly 42
includes first brake 60 having a brake pad 62 adjustably supported
for engagement with the braking surface 52 of the tension roller
46, whereby the brake pad 62 is selectively adjustable between a
first configuration engaged with the braking surface 52 such that
the brake pad 62 applies a first braking force to the tension
roller 46, and a second configuration disengaged from the braking
surface 52, or only minimally engaging the braking surface 52 such
that a braking force in the second configuration is substantially
less than the first braking force. As contemplated herein, the
substantially less braking force caused by the brake pad 62 in the
second configuration may only be sufficient to prevent free rolling
of the tension roller 46, but in no way adversely affects normal
operation of the tension roller 46.
[0035] In the embodiment shown, the brake pad 62 has a generally
flat contact surface 64 and is supported on a brake plate 66 for
movement toward and away from the braking surface 52 of the tension
roller 46 generally along a radial direction of the tension roller
46. To this end, the brake plate 66 is pivotally coupled between
the bearing plate 48 and the top plate 40 at a distance spaced from
the tension roller 46 such that the brake pad 62 is constrained for
movement toward and away from the braking surface 52 of the tension
roller 46 generally along a radial direction of the tension roller
46.
[0036] In one embodiment, the brake plate 66 may be pivotally
coupled between the top plate 40 and the bearing plate 48 by a pin
connection. Alternatively, the brake plate 66 may be formed with
tabs configured to be received in complementary structure on the
top plate 40 and bearing plate 48 to provide a hinge joint. While
the brake assembly 42 has been shown and described herein as having
a brake plate 66 pivotally coupled proximate the tension roller 46
to constrain the brake pad 62 for movement toward and away from the
braking surface 52 along a generally radial direction, it will be
appreciated that various other structure and methods for
constraining movement of the brake pad 62 along a generally radial
direction may alternatively be used.
[0037] The brake assembly 42 further includes a spring 70 biasing
the brake plate 66 and brake pad 62 in a direction toward the
braking surface 52 of the tension roller 46. The spring 70 is
mounted on a shaft 72 extending generally radially from the braking
surface 52. The shaft 72 is coupled with the bearing plate 48 by a
journal 74 for rotation of the shaft 72 about its longitudinal
axis. A length of the shaft includes screw threads 76, and the
shaft 72 supports a pressure block 78 having a tapped aperture 80
for receiving the threads 76 of the shaft 72 such that when the
shaft 72 is rotated the pressure block 78 may be moved axially
along the shaft 72 to increase or decrease a preload of the spring
70 and thereby vary a biasing force of the spring 70 against the
brake plate 66 and brake pad 62. A knob 82 or other control surface
may be provided on an end of the shaft 72 opposite the threaded
portion, to facilitate rotating the shaft 72 to vary the preload of
the spring 70.
[0038] In the embodiment shown, movement of the pressure block 78
along the shaft 72 is guided by a guide rod 84 extending between
the brake plate 66 and distal end 86 of the bearing plate 48
supporting the shaft 72. Accordingly, the braking force applied by
the brake pad 62 to the circumferential braking surface 52 of the
tension roller 46 may be selectively adjusted by manually turning
the knob 82 of the shaft 72 to apply a preload to the brake pad 62
with the spring 70. FIG. 4B depicts brake assembly 42 in a
condition wherein the preload applied by spring 70 has been
increased relative to the preload depicted in FIG. 4A by rotating
knob 82.
[0039] In one embodiment, the brake assembly 42 may further include
an indicator 90 that provides a visual indication of the amount of
preload selected by manually manipulating the knob 82, as depicted
in FIGS. 2, 3, and 5. In the embodiment shown, the indicator 90
includes an indicator arm 92 pivotally coupled to the pressure
block 78 for movement with the pressure block 78 as the shaft knob
82 is manipulated to increase or decrease preload of the spring 70.
A first end 92a of the indicator arm 92 extends through an aperture
94 in the top plate 40, and a second end 92b of the indicator arm
92 is visible through a slot 96 in the cover 44 when the cover 44
is secured to the dispenser 12. The cover 44 may include
graduations or other visual features adjacent the slot 96 so that
the position of the second end 92b of the indicator arm 92 viewed
through the slot 96 may give a visual indication of the amount of
preload applied by the spring 70.
[0040] Referring now to FIGS. 2-5, the brake assembly 42 may
further include a release mechanism 100 that enables a user to move
the brake pad 62 from the first configuration engaged with the
braking surface 52, to the second configuration disengaged from the
braking surface 52 (or only minimally engaging the braking surface
52), as depicted generally in FIG. 4C. In the embodiment shown, the
release mechanism 100 includes a lever arm 102 pivotally coupled to
the top plate 40, such as by a pivot pin 104. A cam roller 106 is
mounted to the lever arm 102 for engagement with a cam surface 108
of a cam bracket 110 extending upwardly from the pressure block 78.
A distal end of the lever arm 102, opposite the pivot pin 104,
includes a handle portion 112 whereby a user may apply force to the
handle portion 112 to engage the cam surface 108 of the cam bracket
110 with the cam roller 106 during movement of the lever arm 102
from a first position depicted in FIGS. 4A and 4B, in a direction
toward top plate 40 to a second position depicted in FIG. 4C. As
the cam roller 106 engages the cam surface 108, the pressure block
78 and shaft 72 are forced away from the tension roller 46, thereby
removing the bias of the spring 70 against the brake plate 66 such
that the brake pad 62 can move to the second configuration away
from the braking surface 52. In this configuration, the brake pad
62 either does not engage the braking surface 52, or only applies
minimal force to the braking surface 52 as described above. When
the lever arm 102 is moved from the second position depicted in
FIG. 4C toward the first position depicted in FIGS. 4A and 4B,
movement of the lever arm 102 is limited by engagement between a
transverse stop member 114 and a vertically extending standoff 116.
The distal end 166a of standoff 116 is threaded to receive a nut
118 for securing the cover 44 over the brake assembly 42, as
depicted in FIGS. 4A-4C.
[0041] With continued reference to FIGS. 3 and 4A-4C, and referring
further to FIG. 5, the brake assembly 42 may further include a
second brake that also engages the circumferential braking surface
52 of the tension roller 46. In the embodiment shown, the second
brake comprises a flexible band 120 engaging at least a portion of
the circumferential braking surface 52. One end 120a of the band
120 is secured to a leg 122 of the bearing plate 48, although it
will be appreciated that the band 120 may be secured to any other
suitable structure. A second end 120b of the band 120 is secured to
a post 124 coupled with the top plate 40 of the dispenser 12. In
the embodiment shown, the second end 120b of the band 120 is
secured to the post 124 by a spring member 126, whereby the band
120 is biased by the spring member 126 into engagement with the
circumferential braking surface 52 of the tension roller 46. The
tension of the band 120 against the circumferential braking surface
52 may be selectively adjusted by adjusting the tension in the
spring member 126. The second brake applies a braking force against
the circumferential braking surface 52 that is substantially less
than the braking force of the first brake. In one embodiment, the
braking force of the second brake is selected to prevent free
rolling of the tension roller 46 while otherwise allowing the
tension roller 46 to be rotated during threading of film 14 through
the dispenser 12. Alternatively, the braking force of the second
brake may be selected to provide a minimum resistance to rotation
of tension roller 46 that will not cause film 14 to be pulled out
of clamp structure that initially secures the film 14 to the load
16 when wrapping of the load 16 with the film 14 is started. In
use, the second brake therefore prevents free rolling of the
tension roller 46 when the first brake is in the second
configuration and disengaged, or substantially less engaged, than
the first configuration.
[0042] Referring now to FIGS. 7 and 8, a second exemplary
embodiment of a brake assembly 130 in accordance with the
principles of the present invention is described. In this
embodiment, a flat brake pad 132 is supported on a brake arm 134
for pivotal movement with the brake arm 134 about a pivot axis 136
spaced from the tension roller 46 such that the brake pad 132 is
movable into and out of engagement with the circumferential braking
surface 52 of the tension roller 46, generally along a radial
direction of the tension roller 46. In this embodiment, a first end
134a of the brake arm 134 is supported for pivotal movement about
the pivot axis 136 by a tie rod 138. The tie rod 138 extends from a
support block 141 coupled to the top plate 40a of the dispenser
12a, and is operatively coupled to a first end 134a of the brake
arm 134. Accordingly, the pivot axis 136 is generally located at
the intersection of the brake arm 134 and the tie rod 138. The
brake assembly 130 further includes a solenoid actuator 140
operatively coupled to a second end 134b of the brake arm 134, at a
location spaced from the pivot axis 136 and the brake pad 132. In
the embodiment shown, the solenoid actuator 140 is coupled to the
top plate 40a of the dispenser 12a by an L-shaped bracket 142. The
output shaft, or armature, 144 of the solenoid 140 is secured to
the second end 134b of the brake arm 134 by a coupling member 146.
When the solenoid 140 is actuated to retract the armature 144, the
brake arm 134 is moved about the pivot axis 136 such that the brake
pad 132 is moved into engagement with the braking surface 52 of the
tension roller 46. Because the solenoid 140 is spaced a distance
from the pivot axis 136, braking force applied by the brake pad 132
to the braking surface of the tension roller 46 is increased by
leverage of the brake arm 134 about the pivot axis 136.
[0043] Prior to the development of the embodiment depicted in FIGS.
7-8, it was believed that solenoids would not be suitable for use
in braking a tension roller in a stretch wrapping operation because
it was believed that a sufficient amount of force could not be
developed over the relatively short stroke of the armature. The
mechanical advantage provided by the increased leverage of the
brake arm 134 about pivot axis 136 enables the solenoid actuator
140 to cause brake pad 132 to engage the braking surface 52 with
sufficient force to enable control of the tension roller 46 as
described herein.
[0044] In operation, the solenoid actuator 140 may be actuated to a
first condition wherein the brake pad 132 engages the braking
surface 52 with a first braking force that slows rotation of the
tension roller 46 to stretch the film material 14 during wrapping
of a load 16. The actuator 140 may also be actuated to a second
condition wherein the brake pad 132 engages the braking surface 52
with a second braking force that is less than the first braking
force, and which prevents free rolling of the tension roller 46
while still allowing the tension roller 42 to rotate when tension
is applied to the film web 14, to facilitate threading film 14
through the dispenser 12a. Alternatively, the second braking force
may be selected to provide a minimum resistance to rotation of
tension roller 46 that will not cause film 14 to be pulled out of
clamp structure that initially secures the film 14 to the load 16
when wrapping of the load 16 with the film 14 is started. The
actuator 140 may also be actuatable to a third condition wherein
the brake pad 132 engages the braking surface 52 of the tension
roller 46 with a third braking force that locks the tension roller
46 against rotation. The third condition of the actuator 140 may be
useful to facilitate intentional tearing or breaking the film 14
after a load 16 has been wrapped. The actuator 140 may also be
actuatable to a fourth condition wherein the brake pad 132 is
either disengaged from the braking surface 52, or the brake pad 132
only engages the braking surface 52 with a negligible force.
[0045] Actuator 140 may be remotely adjustable to vary the braking
force applied to the braking surface 52 for the various operating
conditions of the actuator 140 while the stretch wrapping machine
10 is in use. The actuator 140 may also be programmable to
establish multiple settings of the actuator 140 corresponding to
the various operating conditions. While the brake assembly 130 has
been shown and described as including a solenoid actuator 140 for
applying braking force to the tension roller 46 using a brake arm
134, it will be appreciated that various other actuators may
alternatively be used to apply braking force to the tension roller
46. As non-limiting examples, such actuators may include linear or
rotary actuators, magnetic, electronic, hydraulic, or pneumatic
devices, or any other device suitable for applying force to move
the brake arm 134 to bring the brake pad 132 into and out of
engagement with the braking surface 52 of the tension roller
46.
[0046] In the embodiments depicted in FIGS. 2-5, 7, and 8, the
brake pads engage only a portion of an area of the circumferential
braking surface 52. The area can be represented in part by an arc
that is defined by swinging a radius from the rotational axis of
tension roller 46 through an acute angle.
[0047] Referring now to FIGS. 2 and 6A-6B, an exemplary film roll
support post 32 in accordance with the principles of the present
invention will be described. In the embodiment shown, the support
post 32 is mounted to the dispenser 12 and is fixed against
rotation about its longitudinal axis. The outer peripheral surface
150 of the post 32 is sized to be received within the inner
diameter of a supply roll 18 mounted thereon. A first end 32a of
the post 32 is secured to the bottom plate 30 of the film dispenser
12, and a thrust washer 152 and bushing 154 are provided thereon
for engaging the core of a roll 18 of film material 14 placed over
the post 32. The bushing 154 and thrust washer 152 facilitate
rotation of the supply roll 18 around the post 32 as film material
14 is drawn from the supply roll 18 for application to a load 16
during wrapping. A selectively removable top cap 156 may be
provided at the second end 32b of the post 32 to constrain the
supply roll 18 thereon.
[0048] The post 32 further includes a sheet of pliable material 160
coupled with the outer peripheral surface 150 of the post 32 and
extending generally circumferentially around at least a portion of
the outer peripheral surface 150 of the post 32. At least a portion
of the pliable sheet material 160 is secured to the circumferential
surface 150 of the post 32, such as with fasteners 162, at a
location generally opposite the tension roller 46 in the dispenser
12. The length of the pliable sheet 160 is selected such that a
portion of the pliable sheet 160 generally opposite the fasteners
162 is bowed to extend outwardly away from the outer peripheral
surface 150 of the post 32, and in a direction generally toward the
tension roller 46. Accordingly, when a roll 18 of film material 14
is placed over the post 32, the outwardly bowed pliable material
160 biases the roll 18 of film material 14 in a direction toward
the tension roller 46, as generally depicted in FIGS. 6A and 6B.
The pliable sheet 160 is configured on the post 32 such that the
pliable sheet 160 remains in engagement with the various sizes of
cores 164 provided on supply rolls 18 used with the film dispenser
12, and applies a friction force to the cores sufficient to prevent
the supply rolls 18 from freely rotating on the post 32. It has
also been found that the pliable sheet 160 reduces or eliminates
force variations in the film web 14 that would otherwise be present
due to oscillating displacement of the film rolls 18 about the post
32.
[0049] While the post 32 has been shown and described herein with a
pliable sheet 160 secured thereto for biasing the film roll 18 in a
direction toward the tension roller 46, it will be appreciated that
a tube of pliable material may alternatively be secured to post 32
in a manner similar to the pliable sheet 160, such that a portion
of such tube extends outwardly from the post 32 to bias the film
roll 18 in a direction toward tension roller 46.
[0050] While the exemplary embodiments shown and described with
respect to FIGS. 2-8 include braking surfaces defined on
circumferentially extending portions of a tension roller proximate
the circumferential film engaging surface 50, and include brake
pads that move generally along radial directions relative to a
rotational axis of the tension roller, it will be appreciated that
other embodiments in accordance with the principles of the present
invention may include various other types of braking surfaces, and
may have brake pads that move into engagement with braking surfaces
other than along radial directions, as may be desired.
[0051] Referring now to FIGS. 9, 10A, and 10B, a third exemplary
embodiment of a brake assembly 170 for use with a film dispenser
12b in accordance with the principles of the present invention is
described. Various components of the film dispenser 12b are similar
to those described above with respect to FIGS. 1-2 and 7-8, and
similar features are similarly numbered. In this embodiment, the
brake assembly 170 includes a brake disk 172 coupled with a distal
end of the tension roller 46 such that the rotational axis 174 of
the disk 172 corresponds with the rotational axis of the tension
roller 46. A braking surface 176 is defined on a circumferentially
extending portion of the disk 172, whereby the braking surface 176
extends circumferentially around the tension roller 46 relative to
the circumferential film engaging surface 50.
[0052] The brake assembly 170 further includes a brake pad 178
supported on a first end 180a of a brake arm 180 for pivotal
movement with the brake arm 180 about a pivot axis 182 spaced from
the tension roller 46 such that the brake pad 178 is movable into
and out of engagement with the braking surface 176 on disk 172,
generally along a direction that is substantially parallel to the
rotational axis 174 of the brake disk 172. In this embodiment, the
first end 180a of the brake arm 180 is supported for pivotal
movement about the pivot axis 182 by a shaft 184, wherein the pivot
182 axis is substantially perpendicular to the rotational axis 174
of the disk 172. The shaft 184 is supported by a pair of spaced
apart journal brackets 186 coupled with the top plate 40 of the
dispenser 12b. It will be appreciated, however that brake arm 180
may alternatively be supported by various other structure for
pivotal movement about a pivot axis such that the brake pad 178 is
movable into and out of engagement with the braking surface 176 on
disk 172.
[0053] In another embodiment, brake pad 178 may alternatively be
supported on an actuator for movement into and out of engagement
with the braking surface 176, without being mounted on a brake arm
180. For example, brake pad 178 may be mounted on the armature of a
solenoid actuator such that actuation of the armature in directions
toward or away from the brake disk 172 moves the brake pad 178 into
and out of engagement with the braking surface 176 on brake disk
172. In the embodiment shown, the brake pad 178 has a generally
flat surface for engaging the braking surface 176, but it will be
appreciated that the brake pad 178 may alternatively have various
other configurations suitable for engagement with the braking
surface 176.
[0054] The brake assembly 170 may further include brake force
reaction assembly 190 located adjacent the brake disk 172 and
generally opposite the brake pad 178 to support the disk 172 when
braking forces are applied to the braking surface 176 by the brake
pad 178. In the embodiment shown, the brake force reaction assembly
190 includes a rolling element 192 positioned beneath the brake
disk 172 opposite the brake pad 178. When braking forces are
applied to the braking surface 176 of the disk 172 by engagement of
the disk 172 with the brake pad 178, the rolling element 192 limits
deflection of the brake disk 172 under the action of braking
forces.
[0055] In one embodiment, the brake assembly 170 may be configured
such that the brake disk 172 engages and rides on rolling element
192 of the brake force reaction assembly 190 when tension roller 46
is rotating during operation of the film dispenser 12b.
Accordingly, any geometrical irregularities of tension roller 46
with respect to other components of film dispenser 12b, such as
misalignment or out-of-round conditions of the tension roller 46,
may be accommodated by the brake disk 172 being supported on
rolling element 192.
[0056] The brake assembly 170 further includes a solenoid actuator
194 operatively coupled to a second end 180b of the brake arm 180,
at a location spaced from the pivot axis 182 and the brake pad 178.
In the embodiment shown, the second end 180b of the brake arm 180
and the solenoid actuator 194 are positioned generally above a
contact surface 196a defined by a contact block 196 coupled to the
top plate 40 of the film dispenser 12b. An output shaft, or
armature, 200 of the solenoid 194 is coupled with the contact
surface 196a such that when the solenoid 194 is actuated to extend
the armature 200 in the direction of the contact surface 196a, the
brake arm 180 is moved about the pivot axis 182 to move the brake
pad 178 into engagement with the braking surface 176 of the brake
disk 172, as depicted in FIG. 10B. Because the solenoid actuator
194 is spaced a distance from the pivot axis 182, braking force
applied by the brake pad 178 to the braking surface 176 of the
brake disk 172 is increased by leverage of the brake arm 180 about
the pivot axis 182.
[0057] In operation, the solenoid actuator 194 may be actuated to a
first condition wherein the brake pad 178 engages the braking
surface 176 with a first braking force that slows rotation of the
tension roller 46 to stretch the film material 14 during wrapping
of a load 16. The actuator 194 may also be actuated to a second
condition wherein the brake pad 178 engages the braking surface 176
with a second braking force that is less than the first braking
force, and which prevents free rolling of the tension roller 46
while still allowing the tension roller 46 to rotate when tension
is applied to the film web 14, to facilitate threading film 14
through the dispenser 12b. Alternatively, the second braking force
may be selected to provide a minimum resistance to rotation of
tension roller 46 that will not cause film 14 to be pulled out of
clamp structure that initially secures the film 14 to the load 16
when wrapping of the load 16 with the film 14 is started. The
actuator 194 may also be actuatable to a third condition wherein
the brake pad 178 engages the braking surface 76 of the brake disk
172 with a third braking force that locks the tension roller 46
against rotation. The third condition of the actuator 194 may be
useful to facilitate intentional tearing or breaking the film 14
after a load 16 has been wrapped. The actuator 194 may also be
actuatable to a fourth condition wherein the brake pad 178 is
either disengaged from the braking surface 176, or the brake pad
178 only engages the braking surface 176 with a negligible
force.
[0058] Solenoid actuator 194 may be remotely adjustable to vary the
braking force applied to the braking surface 176 for the various
operating conditions of the actuator 194 while the stretch wrapping
machine 10 is in use. The solenoid actuator 194 may also be
programmable to establish multiple settings of the actuator 194
corresponding to the various operating conditions. While the brake
assembly 170 has been shown and described as including a solenoid
actuator 194 for applying braking force to the tension roller 46
using a brake arm 180, it will be appreciated that various other
actuators may alternatively be used to apply braking force to the
tension roller 46. As non-limiting examples, such actuators may
include linear or rotary actuators, magnetic, electronic,
hydraulic, or pneumatic devices, or any other device suitable for
applying force to move the brake arm 180 to bring the brake pad 178
into and out of engagement with the braking surface 176 of the
brake disk 172.
[0059] Referring now to FIGS. 11, 12A, and 12B, a fourth exemplary
embodiment of a brake assembly 210 for use with a film dispenser
12c in accordance with the principles of the present invention is
described. Various components of the film dispenser 12c are similar
to those described above with respect to film dispenser 12b shown
in FIGS. 9, 10A, and 10B, and similar features are similarly
numbered. The brake assembly 210 includes a brake disk 172 coupled
with a distal end of the tension roller 46 such that the rotational
axis 174 of the disk 172 corresponds with the rotational axis of
the tension roller 46. In this embodiment, a braking surface 176 is
defined on circumferentially extending portions of first and second
oppositely disposed sides 172a, 172b of the disk 172, whereby the
braking surface 176 extends circumferentially around the tension
roller 46 relative to the circumferential film engaging surface
50.
[0060] The brake assembly 210 further includes a first brake pad
212 supported on a first end 214a of a first brake arm 214 for
pivotal movement with the first brake arm 214 about a first pivot
axis 216 that is substantially perpendicular to the rotational axis
174 of the disk 172, such that the first brake pad 212 is movable
into and out of engagement with the braking surface 176 on the
first side 172a of the disk 172, generally along a direction that
is substantially parallel to the rotational axis 174 of the brake
disk 172. In this embodiment, the second end 214b of the first
brake arm 214 is pivotally coupled to a support block 218 disposed
on top plate 40 of the film dispenser 12c.
[0061] A second brake pad 220 is supported on a first end 222a of a
second brake arm 222 for pivotal movement with the second brake arm
222 about a second pivot axis 224 that is substantially
perpendicular to the rotational axis 174 of the disk 172, such that
the second brake pad 220 is movable into and out of engagement with
the braking surface 176 on the second side 172b of the disk 172,
generally along a direction that is substantially parallel to the
rotational axis 174 of the brake disk 172. In this embodiment, the
second end 222b of the second brake arm 222 is also pivotally
coupled to the support block 218. It will be appreciated, however
that first and second brake arms 214, 222 may alternatively be
supported by various other structure for pivotal movement about
pivot axes such that the first and second brake pads 178 are
movable into and out of engagement with the braking surface 176 on
disk 172.
[0062] The position of the second brake pad 220 relative to the
braking surface 176 on the second side 172b of the brake disk 172
is selectively adjustable. In the embodiment shown, the position of
the second brake pad 220 is selectively adjustable by a threaded
member 224 disposed on top plate 40 and engaging second brake arm
222. The threaded member 224 can be selectively adjusted to vary
the height above top plate 40 at which the threaded member 224
engages a pad mounting block 226 that supports the second brake pad
220 on the first end 222a of second brake arm 222. It will be
appreciated that various other structure or methods could
alternatively be used to vary the position of the second brake pad
220 relative to the braking surface 176.
[0063] The brake assembly 210 further includes a solenoid actuator
194 supported on bearing plate 48c and operatively coupled to the
first end 214a of the first brake arm 214. In the embodiment shown,
an output shaft, or armature, 200 of the solenoid 194 is coupled
with a pad mounting block 228 that supports the first brake pad 212
on the first end 214a of the first brake arm 214 such that when the
solenoid 194 is actuated to extend the armature 200 in the
direction of the brake disk 172, the first end 214a of the first
brake arm 214 is moved about the first pivot axis 216 to move the
first brake pad 212 into engagement with the braking surface 176 on
the first side 172a of the brake disk 172, as depicted in FIG. 12B.
The brake disk 172 rides on or just slightly above the second brake
pad 220 until the first brake pad 212 is actuated to move into
engagement with the brake disk 172, whereby the brake disk 172 is
engaged by the first brake pad 212 and the second brake pad
220.
[0064] In another aspect in accordance with this embodiment, the
tension roller 46 may be resiliently supported proximate the bottom
plate 30 of dispenser 12c for movement along the longitudinal axis
of the roller, and biased in a direction toward the bearing plate
48c to counteract the weight of the tension roller 46. Supporting
tension roller 46 in this manner allows the vertical position of
the tension roller 46 and brake disk 172 to float relative to the
position of the second brake pad 220, thereby reducing or
eliminating friction between the second brake pad 220 and the
braking surface 176 on the second side 172b of brake disk 172 when
the first brake pad 212 is disengaged from the braking surface 176
on the first side 172a of brake disk 172. In the exemplary
embodiment shown in FIG. 13, tension roller 46 is resiliently
supported proximate bottom plate 30 by a biasing member 230, such
as a spring. It will be appreciated, however, that various other
structure and/or methods may be used to resiliently support tension
roller 46 to counteract the weight of the tension roller 46.
[0065] In operation, the solenoid actuator 194 may be actuated to a
first condition wherein the first and second brake pads 212, 220
engage the braking surface 176 with a first braking force that
slows rotation of the tension roller 46 to stretch the film
material 14 during wrapping of a load 16. The actuator 194 may also
be actuated to a second condition wherein the first and second
brake pads 212, 220 engage the braking surface 176 with a second
braking force that is less than the first braking force, and which
prevents free rolling of the tension roller 46 while still allowing
the tension roller 46 to rotate when tension is applied to the film
web 14, to facilitate threading film 14 through the dispenser 12c.
Alternatively, the second braking force may be selected to provide
a minimum resistance to rotation of tension roller 46 that will not
cause film 14 to be pulled out of clamp structure that initially
secures the film 14 to the load 16 when wrapping of the load 16
with the film 14 is started. The actuator 194 may also be
actuatable to a third condition wherein the first and second brake
pads 212, 220 engage the braking surface 176 of the brake disk 172
with a third braking force that locks the tension roller 46 against
rotation. The third condition of the actuator 194 may be useful to
facilitate intentional tearing or breaking the film 14 after a load
16 has been wrapped. The actuator 194 may also be actuatable to a
fourth condition wherein one or both of the first and second brake
pads 212, 220 are either disengaged from the braking surface 176,
or only engage the braking surface 176 with negligible force.
[0066] Solenoid actuator 194 may be remotely adjustable to vary the
braking force applied to the braking surface 176 for the various
operating conditions of the actuator 194 while the stretch wrapping
machine 10 is in use. The solenoid actuator 194 may also be
programmable to establish multiple settings of the actuator 194
corresponding to the various operating conditions. While the brake
assembly 210 has been shown and described as including a solenoid
actuator 194 for applying braking force to the tension roller 46
using brake arms 214, 222, it will be appreciated that various
other actuators may alternatively be used to apply braking force to
the tension roller 46. As non-limiting examples, such actuators may
include linear or rotary actuators, magnetic, electronic,
hydraulic, or pneumatic devices, or any other device suitable for
applying force to move the first brake arm 214 to bring the first
brake pad 212 into and out of engagement with the braking surface
176 of the brake disk 172.
[0067] In the embodiments depicted in FIGS. 9-12B, the brake pads
engage only a portion of an area of the circumferential braking
surface 176 of brake disk 172. The area can be represented by a
sector on one or both sides of disk 172 (according to the
particular embodiment), wherein the sector is defined by swinging a
radius from the rotational axis of tension roller 46 through an
acute angle.
[0068] While the present invention has been illustrated by the
description of one or more embodiments thereof, and while the
embodiments have been described in considerable detail, they are
not intended to restrict or in any way limit the scope of the
appended claims to such detail. Additional advantages and
modifications will readily appear to those skilled in the art. The
invention in its broader aspects is therefore not limited to the
specific details, representative apparatus and methods and
illustrative examples shown and described. Accordingly, departures
may be made from such details without departing from the scope or
spirit of Applicants' general inventive concept.
* * * * *