U.S. patent application number 13/877657 was filed with the patent office on 2013-12-05 for tool lift mechanism.
This patent application is currently assigned to ISHIDA EUROPE LIMITED. The applicant listed for this patent is Graham Andrew Charles Neale, Lee Michael Vine. Invention is credited to Graham Andrew Charles Neale, Lee Michael Vine.
Application Number | 20130318919 13/877657 |
Document ID | / |
Family ID | 43304234 |
Filed Date | 2013-12-05 |
United States Patent
Application |
20130318919 |
Kind Code |
A1 |
Neale; Graham Andrew Charles ;
et al. |
December 5, 2013 |
TOOL LIFT MECHANISM
Abstract
The present application relates to a lifting apparatus
comprising a first member and a second member; a lifting mechanism
coupled to said first member adapted to move said first member
towards said second member; and a third member coupled to said
first member, the third member slideably moveable through said
second member when said first member is moved towards said second
member. When a predetermined compressive force is applied to said
third member, a latching mechanism responds by latching said second
member to said third member, such that when a further compressive
force is applied to said third member, said first member and
lifting mechanism are isolated from said further compressive
force.
Inventors: |
Neale; Graham Andrew Charles;
(Bournemouth, GB) ; Vine; Lee Michael; (Poole,
GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Neale; Graham Andrew Charles
Vine; Lee Michael |
Bournemouth
Poole |
|
GB
GB |
|
|
Assignee: |
ISHIDA EUROPE LIMITED
Birmingham, West Midlands
GB
|
Family ID: |
43304234 |
Appl. No.: |
13/877657 |
Filed: |
October 7, 2011 |
PCT Filed: |
October 7, 2011 |
PCT NO: |
PCT/GB11/51929 |
371 Date: |
May 7, 2013 |
Current U.S.
Class: |
53/329.2 ;
53/329 |
Current CPC
Class: |
B65B 31/028 20130101;
B65B 31/021 20130101; B65B 7/164 20130101 |
Class at
Publication: |
53/329.2 ;
53/329 |
International
Class: |
B65B 31/02 20060101
B65B031/02 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 7, 2010 |
GB |
1016930.8 |
Claims
1. A lifting apparatus connectable to a tray sealing tool, the
lifting apparatus comprising; a first member and a second member; a
lifting mechanism coupled to said first member adapted to move said
first member towards said second member; a third member coupled to
said first member and slideably moveable through said second member
when said first member is moved towards said second member, a
distal end of the third member, with respect to the first member,
being connectable to a lower tool half of a tray sealing tool such
that when said first member is moved towards said second member,
the lower tool half is moved towards an upper tool half of the
sealing tool, the lifting apparatus further comprising a latching
mechanism, and wherein; when a predetermined compressive force is
applied to said third member, due to the lower tool half contacting
the upper tool half, said predetermined compressive force actuates
the latching mechanism to latch said second member to said third
member, such that when a further compressive force is applied to
said third member due to sealing forces in the tray sealing tool,
said first member and lifting mechanism are isolated from said
further compressive force.
2. The lifting apparatus of claim 1, wherein the latching mechanism
comprises a spring mounted between said third member and said first
member wherein in use said spring is compressed on application of
said compressive force to said third member, and said predetermined
compressive force corresponds to a predetermined point in the
spring's compression.
3. The lifting apparatus of claim 1, wherein the latching mechanism
comprises a latch cam plate having a shaped portion, said latch cam
plate fixedly coupled to said first member, and wherein the
movement of said first member towards said second member causes
said shaped portion to guide a latch so as the latch engages with a
protruding potion on said third member.
4. The lifting apparatus of claim 1, wherein said first member is a
plate.
5. The lifting apparatus of claim 1, wherein said third member is
elongate and coupled to said first member so as to project along
the direction of movement of said first member.
6. The lifting apparatus of claim 1, wherein said lifting mechanism
is a rotatable lifting screw coupled to the first member in such a
manner that rotation of said lifting screw causes movement of said
first member in a plane substantially perpendicular to the rotation
axis of said lifting screw.
7. The lifting apparatus of claim 1, further comprising one or more
third members.
8. The lifting apparatus of claim 5, wherein the lifting screw and
the or each third member are substantially parallel.
9. A tool lift apparatus comprising the lifting apparatus of claim
1, and further comprising; a lower tool half mounted to the distal
end of the or each third member such that, in use, movement of the
first member moves said lower tool half towards an upper tool half,
and wherein; said predetermined compressive force is due to said
lower tool half and said upper tool half contacting.
10. The tool lift apparatus of claim 9, further comprising a second
lifting apparatus, and wherein said lower tool half is mounted to
the distal end of the or each third member of the first and second
lifting apparatuses, and further wherein the first and second
lifting apparatuses are operated in synchrony.
11. The tool lift apparatus of claim 9, further comprising a second
lifting apparatus and a second lower tool half mounted to the
distal end of the or each third member of said second lifting
apparatus, and wherein said first and second lifting apparatuses
are operated independently.
12. The tool lift apparatus of claim 11, further comprising a
second upper tool half corresponding to the second lower tool
half
13. The tool lift apparatus of claim 9, wherein said further
compressive force is caused by a process performed when said lower
tool half and said upper tool half are in contact.
14. A traysealing machine comprising the tool lift apparatus of
claim 9.
15. The traysealing machine of claim 14, wherein the upper tool
half contains a heated plate.
16. The traysealing machine of claim 14, wherein the lower tool
half is adapted to support one or more trays to be sealed.
Description
[0001] The invention relates to a lifting apparatus, particularly
in the context of a tray sealing machine. Here, the term "tray"
means any container having an upwardly facing opening to which a
film is to be heat sealed.
[0002] In the food industry, it is common to package food items in
heat sealed trays. Conventionally, trays are transported along a
conveyer and filled with the desired food items. The tray is then
fed, typically with a plurality of other trays, to a tray sealing
machine.
[0003] The tray sealing machine typically comprises a lower tool
half on which the tray(s) is positioned, and an upper tool half.
The lower tool half is lifted towards the upper tool half via a
lifting mechanism, and the upper and lower tool halves are clamped
together to generate an air tight seal. The lower tool half has an
ejector plate which lowers the trays into a recess as the lower
tool half is lifted towards the upper tool half. The sealing
process can then take place.
[0004] Lifting mechanisms using a motor-driven spindle to lift the
lower tool half are known in the art. However, when the sealing
process takes place, a large force is placed on the lifting
spindle, much larger than the load placed on the spindle during
lifting of the lower tool half. This large force placed on the
lifting spindle could cause it to buckle, having serious
consequences not only for the output of the tray sealing machine,
but also for safety.
[0005] In order to overcome this problem, such a spindle is
commonly manufactured with a relatively large diameter to improve
its strength in order to protect against buckling. This increases
cost since more material is required for the larger spindle, and a
more powerful motor is needed in order to drive it.
[0006] Alternatively or in addition, a large high power
electromechanical brake may be used to reduce the forces
experienced by the spindle. However, this also increases cost due
to the increased complexity and power consumption.
[0007] What is needed in the art is a lifting mechanism for a tray
sealing machine that prevents the problem of the lifting mechanism
buckling or being damaged under the high loads caused by the
sealing process, without compromising on the efficiency, speed and
cost of the tray sealing machine.
[0008] US2009/0288365 discloses a packaging machine having a
lifting unit. The lifting unit has preferably two spindles, each
attached to a lifting plate by a spindle bearing. Two guiding rods
are also mounted on each lifting plate, which are connected at
their upper end to a lower tool half. When the lower tool half has
been raised to the desired position by the spindles, brakes
independently mounted to each guiding rod are actuated, thus
avoiding undesired lowering of the lifting unit during operation.
As the lifting plates are mounted via the spindle bearings, the
spindles are kept stationary, and are thus exclusively stressed by
tension, excluding the risk of buckling.
[0009] However, in the disclosure of US2009/0288365, the spindles
are still subject to large forces, even if they are in tension. The
spindle will have to be designed to account for these forces.
Moreover, the spindle bearings may be damaged by being subject to
said forces.
[0010] In accordance with the present invention, a lifting
apparatus is provided comprising; a first member and a second
member; a lifting mechanism coupled to said first member adapted to
move said first member towards said second member; a third member
coupled to said first member and slideably moveable through said
second member when said first member is moved towards said second
member, and a latching mechanism wherein; when a predetermined
compressive force is applied to said third member, the latching
mechanism responds by latching said second member to said third
member, such that when a further compressive force is applied to
said third member, said first member and lifting mechanism are
isolated from said further compressive force.
[0011] A key advantage of this invention is that when the further
compressive force is applied to the third member, this force is
transferred through the latching mechanism to the second member.
This isolates the first member and, importantly, the lifting
mechanism, from said further compressive force. This means that the
lifting mechanism does not have to be specifically designed to take
into account the further force, making manufacture simpler, and
reducing the amount of material required.
[0012] Further, the latching mechanism advantageously latches the
second member to the third member automatically on application of
the predetermined compressive force. Other automatic latching
mechanisms are envisaged. For example, a pressure sensor could be
used to detect when the lower and upper tool halves are in contact,
and an electronic system used to initiate the latches. The
automatic nature of the latching mechanism allows the lifting
mechanism of the present invention to be used without
supervision.
[0013] Preferably, the latching mechanism comprises a spring
mounted between said third member and said first member wherein in
use said spring is compressed on application of said compressive
force to said third member, and said predetermined compressive
force corresponds to a predetermined point in the spring's
compression. Alternatively, a compressible fluid could be used
instead of a spring.
[0014] In a preferred embodiment, the latching mechanism comprises
a latch cam plate having a shaped portion, said latch cam plate
fixedly coupled to said first member, and wherein the movement of
said first member towards said second member causes said shaped
portion to guide a latch so as the latch engages with a protruding
potion on said third member. Other latching mechanisms are
envisaged, for example electromagnetically actuated latches.
[0015] In a preferred embodiment, the first member is a plate and
said third member is elongate and coupled to said first member so
as to project along the direction of movement of said first
member.
[0016] Preferably, the lifting mechanism is a rotateable lifting
screw coupled to the first member in such a manner that rotation of
said lifting screw causes movement of said first member in a plane
substantially perpendicular to the rotation axis of said lifting
screw.
[0017] This advantageously means that the lifting screw remains
stationary as the lifting plate is raised, allowing for increased
ease of installation as movement of the lifting screw does not have
to be accounted for.
[0018] It will however be appreciated by those skilled in the art
that other lifting mechanisms may be used. For example, the first
member may be moved towards the third member by means of pistons or
a pulley system.
[0019] In a preferred embodiment, the lifting apparatus further
comprises one or more third members. For example, in one embodiment
a second third member is also coupled to said first member via a
spring, and is slideably movable through a second member. In this
embodiment, the second third member provides increased support for
an item to be lifted by the lifting apparatus, where the item is
supported by the third members.
[0020] In one embodiment, the lifting screw and the or each third
member are substantially parallel.
[0021] The lifting apparatus may be included in a tool lift
apparatus, the tool lift apparatus further comprising a lower tool
half mounted to the distal end of the or each third member such
that, in use, movement of the first member moves said lower tool
half towards an upper tool half, and wherein said predetermined
compressive force is due to said lower tool half and said upper
tool half contacting.
[0022] In one embodiment, the tool lift apparatus is employed in a
tray sealing machine, where the further compressive force is due to
a sealing process taking place when the upper and lower tool halves
are in contact and form an air-tight seal. However, the lifting
apparatus may be employed in other instances apart from tray
sealing machines, such as thermoformer machines and press
tooling.
[0023] In one embodiment, such a tool lift apparatus further
comprises a second lifting apparatus, wherein said lower tool half
is mounted to the distal end of the or each third member of the
first and second lifting apparatuses, and further wherein the first
and second lifting apparatuses are operated in synchrony.
[0024] The lower tool half of such an embodiment thus
advantageously has greater support as it is supported by two
lifting apparatuses. Such a tool lift apparatus may be utilised in
a single lane tray sealing machine.
[0025] In an alternative embodiment, the tool lift apparatus
further comprises a second lifting apparatus and a second lower
tool half mounted to the distal end of the or each third member of
said second lifting apparatus, and wherein said first and second
lifting apparatuses are operated independently. There may also be
an independent upper tool half corresponding to the second lower
tool half.
[0026] This embodiment provides increased flexibility in the use of
the tool lift apparatus, especially when used in a dual lane tray
sealing machine for instance. For example, one lane may be used for
large trays that are sealed three at a time, and the second lane
used to seal small trays that are sealed four at a time and at a
faster rate. The independent lifting apparatuses and tool halves
allow for maximum flexibility in such a situation, increasing
throughput and efficiency of the tray sealing machine.
[0027] Embodiments of the present invention will now be described
and contrasted with the prior art with reference to the following
drawings in which:
[0028] FIG. 1 is a schematic side view partly in section of a
lifting apparatus according to an embodiment of the present
invention with a lifting plate in a lower position;
[0029] FIG. 2 is a view similar to FIG. 1, but showing the lifting
plate in an upper position;
[0030] FIG. 3 is a view of a lifting apparatus of the present
invention in use in a single lane tray sealing machine;
[0031] FIG. 4 is a view of a lifting apparatus of the present
invention in use in a dual lane tray sealing machine;
[0032] FIG. 5a is a staggered cross-section of the lifting
apparatus of FIGS. 1 and 2, showing the latching mechanism in more
detail;
[0033] FIG. 5b is another staggered cross-section of the lifting
apparatus of FIGS. 1 and 2, showing the latching mechanism in more
detail;
[0034] FIG. 6a is another staggered cross-section of the lifting
apparatus of FIGS. 1 and 2, showing the latching mechanism in more
detail; and
[0035] FIG. 6b is a further staggered cross-section of the lifting
apparatus according to FIGS. 1 and 2, showing the latching
mechanism in more detail.
[0036] In the following description, directional terms such as
"raised", "lowered", "upper", "lower" etc. are used for clarity in
explaining the figures and are not intended to be limiting.
[0037] Considering first FIG. 1, there is shown a lifting apparatus
comprising two pillars 1a, 1b attached to a lifting plate 7. In
this embodiment, each pillar 1 is slideably moveable through a
housing structure 9 surrounding said pillar, and each housing
structure 9 is mounted on a stationary upper plate 11. Other means
of mounting the housing structures are envisaged.
[0038] The pillars may be circular or square in cross-section.
Other cross-sectional shapes may be used.
[0039] In the following description, a single pillar la will be
referred to for ease of understanding.
[0040] The lifting plate 7 is raised towards the upper plate 11 by
means of a lifting screw 2 rotateably mounted via bearings 2a in
the upper plate 11 and received in a screw threaded bush 2b in the
lifting plate 7. A gear 3b is fixed to the upper end of the screw
and is connected to a motor 3 by tooth belt 3a. The lifting screw 2
is rotated by said motor 3, causing the lifting plate 7 to move
upwards towards plate 11 in a plane substantially perpendicular to
the axis of rotation.
[0041] As will be appreciated by those skilled in the art, although
FIGS. 1 and 2 show the lifting screw 2 located between the two
pillars 1a, 1b, with the pillars and lifting screw substantially
parallel, this is not necessarily the case. The lifting apparatus
of the present invention may contain any number of pillars.
[0042] As seen in FIG. 2, upon rotation of the lifting screw 2, the
lifting plate 7 is moved relative to the lifting screw 2. This
advantageously simplifies installation of the lifting mechanism,
since the lifting screw 2 remains stationary with respect to the
motor 3 and upper plate 11, and thus the installation does not need
to take into account movement of the lifting screw. Other means of
raising the lifting plate 7 are envisaged, for example hydraulic
pillars mounted beneath the plate in order to push it upwards
towards upper plate 11.
[0043] In an embodiment of the invention, the lifting apparatus as
depicted in FIG. 1 is used in a tray sealing machine. In such an
embodiment, trays to be sealed are loaded onto a lower tool half
(20 in FIG. 3) attached to the upper end of each pillar 1a, 1b. As
the lifting plate 7 is raised, the lower tool half is raised
towards an upper tool half (not shown). The lower tool half has an
ejector plate which lowers the trays into a recess as the lower
tool half is raised towards the upper tool half. The lower and
upper tool halves come into contact and form an air tight seal. The
upper tool half is heated so as to seal the film to the tray.
[0044] The two-pillar lifting apparatus depicted in FIGS. 1 and 2
is referred to as a module. In one embodiment, depicted in FIG. 3,
a single lane tray sealing machine 100 comprises two modules 101,
102 in lateral proximity with a predefined pitch between the four
pillars. Both modules 101, 102 are connected to a common drive
motor 3 via a tooth belt, and all four pillars are driven together,
raising the lower tool half 20 of the tray sealing machine towards
the upper tool half (not shown).
[0045] In another embodiment seen in FIG. 4, two modules 101, 102
may be used in a dual-lane tray sealing machine 200. In this
embodiment each module has a separate drive motor 3 and separate
tooth belts. This allows each module to operate independently,
allowing two separate lower tool halves 20a, 20b to operate
independently. There may be a common upper tool half (not shown)
for both lower tool halves 20a, 20b, or each lower tool half may
have a corresponding independent upper tool half. The modules 101,
102 are the same as those seen in FIG. 3 but are reversed from the
single lane application. The pitch between the modules can be
altered to suit the particular dual lane application due to the
asymmetric design of the modules.
[0046] As the lifting apparatus of the present invention can be
used in a dual lane situation with independent tray sealing machine
lower tool halves 20a, 20b, this advantageously allows different
tray sizes to be packaged and sealed concurrently, increasing
throughput. Enabling the use of independently operable lower tool
halves also allows different numbers of trays to be sealed at a
time on each lane. For example, two trays can be sealed at a time
on one lane, and three at a time on the other. In this way,
flexibility of tray sealing is further increased.
[0047] It is envisaged that a lower tool half of a tray sealing
machine may be supported by any number of pillars. For example, one
pillar may be used to support a lower tool half.
[0048] For ease of understanding, the following description will
refer to a single module.
[0049] The sealing load placed on the lifting mechanism is far
greater than the lifting load caused by raising the lower tool
half, as the sealing process forces the upper and lower tool halves
apart. The lifting apparatus of the present invention allows the
lifting screw 2 and motor 3 to be isolated from the sealing load,
as described below. This means that the lifting screw 2 does not
need to be as robust as in the prior art, and can thus have a
relatively small diameter, advantageously minimising manufacturing
cost and mechanism size. Similarly, motor 3 and any
electro-mechanical brake can be downsized as it does not have to
drive a large lifting screw 2 or lifting mechanism designed to
withstand the sealing load.
[0050] When the lower tool half first makes contact with the upper
tool half, motor 3 continues to rotate the lifting screw 2, raising
the lifting plate 7 upwards towards the upper plate 11. As seen in
FIGS. 1 and 2, a spring housing 13 is attached to the underside of
lifting plate 7, said spring housing 13 housing two springs 6
coupled to the spring housing 13 and pillar 1a. A corresponding
spring housing 13 with two springs 6 is provided for pillar 1b,
however for ease of understanding the lifting apparatus is
described with reference to pillar 1a in the following
description.
[0051] As motor 3 continues to drive lifting screw 2 when the upper
and lower tool halves are in contact, pillar 1a remains stationary
but lifting plate 7 continues to move upwards towards plate 11,
thus compressing springs 6. In the present embodiment the two
springs are identical and so compress at the same rate, although
different springs may be used. At a predetermined point in the
compression of the springs, a latching mechanism responds by
latching the housing structure 9 to the pillar 1a. The latching
mechanism comprises latches 4 located on the housing structure 9
which engage with each protruding portion 12 on the pillar 1a. The
motor 3 stops at a predetermined position set in the motor control
unit (not shown), but could equally be controlled by a sensor or
switch attached to the mechanism.
[0052] In the embodiment shown in FIGS. 1 and 2, the spring
housings 13 contain two springs each. However, this is not
necessarily the case and any number of springs may be used, for
example a single spring. Alternatively, a hydraulic system using a
compressible fluid may be implemented instead of the use of a
spring(s).
[0053] The housing structure 9 and spring(s) 6 are not limited to
their described position. For example, the spring housing 13 could
be mounted on the upper side of lifting plate 7, thus placing the
spring(s) 6 under tension as the lifting plate 7 continues to rise
when the upper and lower tool halves first come into contact.
[0054] As the pillars are now coupled to the housing structures 9
via latches 4, the load placed on pillars 1 due to the sealing
process is transferred through latches 4 to the housing structures
9. This therefore advantageously isolates the lifting screw 2 and
motor 3 from these high loads as the pillars 1 are coupled to
lifting plate 7 via spring 6.
[0055] The latching mechanism will now be described in more detail
with reference to FIGS. 5a, 5b, 6a and 6b. The latching mechanism
comprises latches 4 and spring 6 as described above, as well as
latch cam plate 5 and cam follower rollers 10. Its operation will
be described below.
[0056] FIGS. 5a, 5b, 6a and 6b are staggered cross-section diagrams
taken along the axis x-x'. FIG. 5a shows a cross section taken
through a pillar 1a, and FIG. 5b shows a cross section taken
through latch cam plate 5, both before the latches 4 are engaged.
The two views are of the same pillar 1a and have been shown side by
side for ease of comparison and do not represent two independent
pillars. FIGS. 6a and 6b show the equivalent views when the latches
4 are engaged.
[0057] Considering first FIGS. 5b and 6b, latch cam plate 5
(hereafter referred to as latch plate) fixedly coupled to lifting
plate 7 is moved towards latches 4 as the lifting plate 7 is
raised. Latches 4 comprise two complementary structures 4a and 4b
facing each other as seen in FIGS. 5b and 6b. Each complementary
structure 4a, 4b contains a cam follower roller 10 (hereafter
referred to as roller).
[0058] When the lower tool half comes into contact with the upper
tool half, as explained above, lifting plate 7 continues to rise
and compresses spring(s) 6. The latch plate 5, coupled to lifting
plate 7, will come into contact with the rollers 10, specifically
at the shaped portion 14 of the latch plate. The spring(s) 6 will
continue to compress until, at a predetermined compression point,
the spring(s) becomes compressed enough to positively drive the
latch plate 5 further upwards, forcing the rollers 10 along guided
portion 14 into the recessed portion 16 of the latch plate 5.
[0059] This causes the complementary structure 4a and 4b to move
inwards towards each other, engaging with the protruding portions
12 on the pillar 1, as seen in FIGS. 5a and 6a. The motor 3 is
stopped on engagement of the latches with the protruding portions
and thus the lifting plate 7 becomes stationary. The sealing
process can then occur, transferring the high loads through the
latches 4 to the housing structure 9, thus isolating the lifting
screw 2 and motor 3 from said loads.
[0060] On completion of the sealing process, the motor 3 is driven
in the reverse direction, thus causing the lifting plate 7 to lower
away from the upper plate 11. This places the springs 6 under
tension, and at a predetermined point in the extension of the
springs, the rollers 10 are released from the recessed portion 16
in the latch plate 5, and the shaped portion 14 of the latch plate
positively drives the complementary structures 4a and 4b back to
their original position. The complementary structures are retained
in their original position by the proximity of the pillar passing
the latches 4, as seen in FIG. 5a. This releases protruding portion
12 on the pillar 1.
[0061] As seen in FIGS. 1 and 2, although two protruding portions
12 are shown on opposing sides of pillar one or more protruding
portions and corresponding latches 4 could be used. Similarly,
although two latch plates 5 are shown on the lifting plate 7 on
opposing sides of pillar 1a, a single latch plate 5 may be used, or
more then two latch plates may be used.
[0062] Other latching mechanisms are envisaged. For example,
electronically actuated latches could be engaged at the desired
time using a control unit.
[0063] When the lifting plate 7 is in its lower position, the
sealed trays can be transported away from the lower tool half, for
example by gripper arms and a conveyer, and unsealed trays to be
sealed can be transported on to the lower tool half for the process
to repeat.
[0064] The lifting apparatus is not restricted to the described
embodiment. For example, the upper tool half may be moved towards a
stationary lower tool half. It is also envisaged that the lifting
mechanism of the present invention can be used in conjunction with
a twin lane device, an example of which being the QX-1100
manufactured by Ishida Europe Limited of Birmingham, United
Kingdom.
[0065] Although described with relation to a tray sealing machine,
the lifting apparatus of the present application can be used in
other scenarios and apparatuses.
* * * * *