Information
-
Patent Grant
-
6223505
-
Patent Number
6,223,505
-
Date Filed
Tuesday, September 7, 199925 years ago
-
Date Issued
Tuesday, May 1, 200124 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Vo; Peter
- Desai; Hemant M
Agents
-
CPC
-
US Classifications
Field of Search
US
- 053 450
- 053 550
- 053 148
- 053 236
- 053 578
- 221 200
- 221 218
- 221 253
- 414 7976
- 198 443
- 198 55013
-
International Classifications
-
Abstract
A machine and a method for wrapping an elongated object, such as a drinking straw, with a plastic film are disclosed. The machine has a drive for continuously advancing a thin narrow film strip from a supply roll to a wrapper loading and forming station. The wrapper loading and forming station has a trough former for folding the advancing film strip into a film trough. An inserting device positions spaced-apart elongated objects, such as the drinking straws, into the film trough of the advancing film strip for engagement by the film trough. The objects are supplied by a dispenser and disposed in a pre-oriented manner to be grasped by the inserting device. The film trough is advanced through sealing and severing stations wherein individually wrapped elongated objects or straws are produced.
Description
TECHNICAL FIELD
The present invention relates to a machine and a method for wrapping an elongated object, such as a drinking straw, with a plastic film, and to the wrapped object resulting therefrom. More specifically, the invention relates to a straw wrapping machine and method and a straw wrapped in a plastic film wrapper which seals the straw therein.
BACKGROUND ART
Straws of all types are packaged in different manners whereby to protect the straw in a sanitary manner to prevent contamination thereof. It is also known to package thermometers in sterilized wrappers. It is still further known to attach short drinking straws on beverage packages or cans with shrink wrappers or other straw attaching films. However, the majority of straws are packaged individually in thin paper wrappers of the type commonly used to manufacture cigarettes. A disadvantage of such wrappers is that they cannot be used to sterilize the straws due to their absorbency. Furthermore, because these papers are highly absorbent, they are susceptible to contamination by liquids should liquid be splashed against the wrapped straw or the straw placed on a liquid spill which we often find on counter tops where drinks of all sorts are dispensed. Another disadvantage of using these thin paper wrappers is that it is difficult to print on these papers. Also, because the paper is highly absorbent, if the wrapped straw was in contact with liquid, the liquid could also dissolve the ink and contaminate the straw inside the wrapper. A further disadvantage is that because these straws are usually made of plastics material, it is difficult to recycle straws in their paper wrappers as the two materials need to be separated for recycling. Accordingly, they are destroyed and not recycled.
SUMMARY OF INVENTION
It is a feature of the present invention to provide a machine, a method and a plastic film wrapped straw which substantially overcomes the above-mentioned disadvantages of the prior art.
Another feature of the present invention is to provide a machine for automatically wrapping straws with a thin plastic film strip which is contained in a roll and wherein the plastic film is a co-extruded film structure with a sealing layer permitting high line speed and a core providing the rigidity and mechanical properties required for good machinability and which permits a substantial increase in film length as compared to paper straw wrappers of the same diameter roll thereby resulting in less frequent machine stoppage for reloading of wrapper strip rolls.
Another feature of the present invention is to provide a method of wrapping straws with thin plastic film strips which is substantially fully automatic and which can handle elongated tubular objects, such as straws, of different dimensions.
Another feature of the present invention is to provide a straw sealed in a thin plastic film wrapper which is water-proof and on which wrapper there is provided printed matter and/or graphics.
Another feature of the present invention is to provide a straw wrapped in a thin plastic film and wherein the straw and wrapper are completely recyclable by the manufacturer.
Another feature of the present invention is to provide a thin plastic wrapper for elongated articles and wherein the wrapper is completely sealed and can be easily sterilized.
According to the above features, from a broad aspect, the present invention provides a machine for wrapping an elongated object with a waterproof plastic film. The machine comprises drive means for continuously advancing a narrow thin film strip from a supply means to a wrapper loading and forming means. Tension means is provided to maintain a continuous tension on the film drawn from the supply means. The wrapper loading and forming means has a trough former for folding the advancing film strip into a film trough. Insert means is provided for positioning spaced-apart elongated objects into the film trough of the advancing film strip for engagement of the objects and conveyance by the film trough. Object dispensing means is provided for supplying pre-oriented elongated objects to the insert means. Sealing and severing means are provided for heat sealing the film trough about individual ones of the elongated objects and severing the film trough between adjacent ends of the elongated objects to form individually wrapped elongated objects.
According to a further broad aspect of the present invention there is provided a method of wrapping an elongated object, such as a straw, with a waterproof thin plastic film. The method comprises continuously advancing a narrow thin film strip from a supply roll to a wrapper loading and forming station by drive means. Tension means is provided to maintain a continuous tension on the film drawn from the supply means. The narrow thin film strip is folded in a trough former to form a film trough having opposed spaced film side walls. Spaced-apart elongated objects are inserted into the advancing film trough whereby each object is frictionally engaged and conveyed by the film side walls of the film trough. A top end portion of the opposed film side walls is longitudinally sealed together with the object thereunder. The folded film trough is then transversely sealed and severed at opposed ends of the object therein and the plastic film wrapped objects are discharged.
According to a still further broad aspect of the present invention, there is provided a straw held captive in a waterproof film wrapper formed by a narrow folded plastic film strip defining a trough having opposed side walls between which the straw is held captive between a longitudinal seal adjacent elongated end edges of the side walls and transverse seals spaced from opposed ends of the straw.
According to a further broad aspect of the present invention there is provided an elongated object wrapped in a waterproof thin film strip formed by the above described method and apparatus and wherein the elongated object may be a thermometer, stir sticks or any such objects capable of being automatically dispensed in a plastic film trough as formed hereinabove by the described machine and method.
According to a still further broad aspect of the invention the plastic film is a co-extruded polyolefin film structure comprising a sealing layer with a seal initiation temperature lower than 90° C. and a core comprising a mixture of low, medium and/or high density polyethylene and/or polypropylene with an approximate thickness of between 0.5 to 0.7 mil.
BRIEF DESCRIPTION OF DRAWINGS
A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which:
FIG. 1
is a side view of the plastic film wrapping machine of the present invention;
FIG. 2
is a top view of
FIG. 1
;
FIG. 3A
is an enlarged side view of a portion of
FIG. 1
to better illustrate the construction and operation of the wrapper loading and forming stations;
FIG. 3B
is a top view of the vertical sealer and severing roll assemblies;
FIG. 4
is a still further enlarged view of a section of
FIG. 3
showing the discharge end of the straw holding bin in relation to the endless belt straw inserter and its position relative to the trough former;
FIG. 5
is a top view of the straw former and its relationship with the endless belt straw inserter;
FIG. 6
is a perspective view of the plastic film trough former;
FIG. 7
is a side view showing the construction of the holding bin with its straw feeding and alignment mechanisms to position the straws in side-by-side parallel relationship in a discharge magazine;
FIG. 8
is an enlarged view of the horizontal throat section adjacent the discharge conveyor;
FIG. 9
is a fragmented side view showing a section of the horizontal throat section of a discharge conveyor in relation to the buffer wall;
FIG. 10
is a front end view of the holding bin and the storage magazine leading to the straw discharge end;
FIG. 11
is an end view showing the construction of the adjustable outer wall of the magazine section of the holding bin;
FIG. 12
is a side view showing the construction of the conveyor and its drive;
FIG. 13
is a top view illustrating the construction of the film roll holder and automatic braking system;
FIG. 14A
is an enlarged view showing the construction of the film core lock assembly and the position of the brake shoe in relation to the brake hub secured to the film roll core support shaft;
FIG. 14B
is a side view of the brake shoe in relation to the brake hub secured to the film roll support shaft; and
FIG. 15
is a perspective view showing a straw wrapped in a thin film plastic strip formed in accordance with the present invention.
FIG. 16
is a transverse section view of FIG.
15
.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to the drawings and more particularly to
FIGS. 1 and 2
, there is shown generally at
10
the machine of the present invention for wrapping an elongated object, such as a drinking straw
11
, as shown in
FIGS. 15 and 16
, in a thin plastic film wrapper
12
. The machine has a housing
13
which is supported on adjustable legs
14
whereby the machine can be leveled. The machine is also provided with a control panel
15
which houses switches, counters, temperature controllers, machine speed indicators, etc. At a supply end
16
of the machine, there is provided a thin plastic film strip roll
17
which is supported on a support shaft assembly
18
. A cylindrical flange
19
is secured to the top wall
20
of the housing at the supply end and a plurality of the film rolls
17
are stored about this cylindrical flange for reloading the machine once the dispensing roll needs to be replaced.
As hereinshown, the thin plastic film strip
21
is trained about various guide rolls and is drawn by a drive feed roll
22
which is spring-biased against an idler roll
23
. The film strip
21
exiting the film roll
17
is first trained about a tension roller
24
which is secured to a pivot arm, as will be described later. The tension roller
24
is displaceable in an arcuate guide slot
25
for reasons which will also be described later. The film strip exiting the drive feed roll
22
is trained about a pair of guide rolls
26
,
26
′ which are disposed under an article loading conveyor
27
. The thin film strip
21
then passes over an inlet roll
28
of a trough former
29
where the thin film strip
21
is folded into a trough for receiving an elongated object, such as the straw
11
therein.
At the outlet of the trough former, the free top end portions
12
″ of the opposed side walls
12
′ of the folded film strip are held captive between a set of draw rolls
30
driven by a belt which is synchronized to the drive feed roll
22
whereby to draw the film trough engaged in a closed folded position with the straw captive therein and disposed under the engaged top free end
12
″ of the wrapper, as shown in FIG.
16
. This top fee end
12
″ is also engaged by a set of heat sealing disc flanges
32
′ of the sealer
32
and which are also rotatably driven by a further belt drive, also synchronized with the drive feed roll
22
and draw rolls
30
. The sealing disc flanges
32
′ are heated to a predetermined temperature to form an elongated seal
34
between opposed side walls.
12
′ of the film wrapper
12
below the top free ends
12
″, and transverse end seals
41
as shown in FIG.
15
. The film trough is then engaged between another set of driven drums
35
of an anvil
39
and knife
38
assembly
36
(see
FIG. 3B
) which is also driven by a belt synchronized with the other belts and the drive feed roll
22
.
With further reference to
FIGS. 3A and 3B
, the vertical anvil and knife assembly
36
, as previously described, is comprised of a pair of drums
35
and
35
′ with drum
35
being provided with a vertical cutting blade or knife
38
extending at a predetermined location and oriented on a vertical axis on the surface of the drum
35
. This cutting edge or blade
38
is disposed to contact the anvil
39
, disposed on the drum
35
′ and positioned at a predetermined location on its outer circumference
40
and aligned for registry with the cutting blade
38
whereby to sever the film trough between opposed ends of adjacent straws being conveyed by the trough and to simultaneously form a vertical end seal
41
at both the trailing end of a forward straw wrapper and the leading end of a trailing straw wrapper. The folded film trough is drawn from the cutting head assembly
36
by a pair of discharge conveyors
42
which, as better seen from
FIG. 2
, is comprised by two endless belts
43
and
43
′ and which form a discharge throat
44
by opposed straight runs of the belt to engage therebetween the top end portions
12
″ of the film wrapper
12
having been completely sealed about the straw
11
and discharged from the cutting head assembly
36
. The straw
11
in its wrapper
12
, as shown at
45
, is then ejected by the discharge conveyor
42
into collecting bins, not shown, or other form of collator for packaging these film wrap straws.
Referring now more specifically to
FIGS. 4
to
6
, there will be described the construction and operation of the trough former
29
and the loading conveyor
27
which dispenses straws from a discharge end
46
of a straw holding magazine
47
of a straw supply bin
48
as shown more clearly in FIG.
1
. As better seen from the perspective view illustrated in
FIG. 6
, the trough former
29
is comprised by a geometric forming plate which defines a tapered bottom wall
49
having a flat wide inlet end
50
and progressively merging opposed side walls
51
and
51
′ tapering to a narrow funnel-like U-shaped rear trough section
52
. The film draw rolls
30
are spaced from the rear end trough section
52
and pull the film strip
21
in folded juxtaposition to progressively form a film trough
21
′ within he forming plate and in which straws
11
are positioned. As clearly shown in
FIG. 6
, the draw rolls
30
are narrow rolls and engage only the top end portions of the folded film trough
21
′ whereby the straw
11
can be conveyed below the narrow draw rolls
30
as it pulls the film trough
21
′ through the plate former
29
. As the film moves into the trough former, the side walls
12
′ of the film come closer together to form a straw engaging section intermediate the flat end
50
and the rear trough section
52
whereby when a straw is disposed in the trough former, the side walls
51
,
51
′ of the film will frictionally engage a leading end of the straw
11
loaded therein by the loading conveyor
27
and convey it, as better seen from
FIGS. 4 and S
.
As shown in
FIG. 4
, the geometric forming plate
29
is secured to an adjustable positioning flange
53
which is secured by bolts
54
extending into respective slots
55
of the flange whereby the position of the trough former
29
can be adjusted up and down and in relation to the inlet roll
28
whereby to ensure proper operation of the trough former to receive the particular objects being dispensed by the loading conveyor
27
.
The loading conveyor
27
is comprised of a narrow endless belt
56
which is rotatably driven between a drive sheave
57
and an idle sheave
58
. The endless belt has a flat run section
59
which is disposed adjacent the straw discharge end
46
of the straw dispensing magazine
47
and is herein provided with three pusher plates
60
secured to the top surface
61
of the endless belt
56
in spaced-apart relationship and disposed a predetermined distance between one another. The pusher plates have a straw end engaging front wall for pushing a straw, such as straw
11
′ at the discharge end
46
, into the trough forming plate
29
, as shown in FIG.
5
. As the front end of the straw
11
′ moves into the trough forming plate
49
, it will be frictionally engaged by the opposed side walls of the film trough
12
and will be grasped thereby and pulled through the trough former along with the film trough
21
′. The pusher plates
60
are provided with an attachment lug
62
which constitutes an adjusting means to secure the position of the pusher plates along the top surface
61
of the endless belt
56
at predetermined distances dependent on the length of the objects, herein straws
11
, being loaded in the film trough.
As previously described, the machine can also be adapted to load different elongated objects into the film trough
21
such as, for example thermometers, stir sticks, etc. As hereinshown, the drive sheave
57
is also secured to its drive shaft
63
through an adjustable connection comprised of bolts
64
extending in arcuate slot
65
formed in the sheave disc. This permits the adjustment of the belt and therefore the pusher plates
60
to position the plates at precise locations with respect to the trailing end position
66
of a straw
11
′ located at the discharge end
46
of the magazine prior to the operation of the machine. Accordingly, the loading conveyor is also synchronized with the drive feed roll
22
and the motors
31
,
33
and
37
.
Referring now to
FIGS. 7
to
11
, there will be described the construction and operation of the straw supply holding bin
48
. The straw supply holding bin
48
is formed by spaced-apart parallel side walls
67
, a front wall
68
, a rear wall
69
and a bottom wall
70
. A straw feed and alignment mechanism
71
is provided and forms a portion of the bottom wall in a discharge area thereof. This mechanism
71
is comprised of a discharge conveyor
72
which is provided by an endless belt
73
which has a serrated upper surface formed by a plurality of rib formations
74
or other means, as better illustrated in
FIG. 9
, wherein to frictionally engage on its surface the straws
11
which are disposed within the bin and transversely aligned between the side walls
67
. Supply means, not shown, is provided to position straws within the bin and this can be done manually or by other automatic loading means.
The bin bottom wall
70
is an inclined wall whereby to direct the straws towards the discharge conveyor
72
. A further discharge conveyor
75
is also coupled to the drive sheave of the discharge conveyor
72
to feed the straws to the discharge conveyor
72
to position the straws into a positioning throat section
77
where the straws are oriented in perfect side-by-side parallel spaced relationship.
With further reference to
FIG. 8
, it can be seen that the positioning throat section
77
is defined by a stationary buffer wall
78
retained in spaced parallel relationship with at least a section of the upper surface
74
of the discharge conveyor
72
. This buffer wall
78
permits the straws
11
to align themselves in the said side-by-side parallel spaced relationship.
The buffer wall
78
is comprised by a plurality of spaced rods
79
which are secured to a frame
80
and held in spaced-apart parallel relationship and at a predetermined distance therebetween. These rods
79
lie in a common plane which is disposed substantially parallel to the friction upper surface
74
of the discharge conveyor belt which has a straight flat run section
59
disposed thereadjacent. A flexible hollow tubular member
82
, which is herein constituted by a straw is disposed about each of the rods
79
in loose spaced relationship therewith. That is to say, the inner diameter of the tubular member
82
is much larger than the outer diameter of the rod
79
so that the tubular members
82
can move up and down and sideways and provide a buffer for the straws
11
being conveyed on the upper surface
61
of the flat run section
59
permitting the straws
11
to align themselves.
The frame member
80
holding the rod
79
is secured to an adjustable flange wall
83
which is adjustable up and down to vary the distance between the tubular rod
79
and the upper surface
61
of the straight run section
59
of the discharge conveyor
72
. The flange wall
83
is secured by bolts
84
which extend through elongated slots
85
to provide this adjustment.
It is pointed out that the discharge conveyor
72
is rotating at a speed slightly higher than the speed of the loading conveyor
27
to ensure that the discharge magazine
47
is always full of straws. Accordingly, as the straws enter the positioning throat section
77
, the upper surface of the conveyor
61
will keep pushing on the straws and they will move slightly up and down and align themselves in a side-by-side relationship as shown in
FIG. 8
as they are free to move up against the flexible tubular members or straws
82
which will also move up and down on their support rods. Therefore the serrated upper surface of the endless belt
73
will slip under the straws when the trough and magazine is full but continue to move the straws in the discharge magazine immediately as straws are discharged from the discharge end
46
thereof.
With reference now to
FIGS. 7
,
10
and
11
, there will be described the construction of the magazine. As hereinshown, the magazine is constituted by a lower vertical discharge section
81
of the bin
48
. At the upper end of the magazine
47
, the endless belt
73
is displaced along a straight vertical travel path
86
which extends substantially transverse to the horizontal straight run section
59
under the buffer wall so that straws will be continuously pushed into the magazine
47
. The magazine
47
is provided by adjustable straw restraining walls
87
and a stationary lower wall section
88
. An opposed adjustable plate
89
is provided below the lower wall section
88
to adjust the width of the discharge end
46
, depending on the size of the straws being packaged. Similarly, the straw restraining wall
87
is adjusted.
As shown in
FIGS. 10 and 11
, the straw restraining walls
87
are comprised of a pair of spaced-apart guide plates
90
which are retained in vertical parallel relationship by adjustable support rods
91
which are secured between side frame members
92
, as shown in FIG.
10
. These guide plates
90
are brass plates which are adjustably positioned relative to the vertical discharge section
86
of the discharge conveyor and depending on the outer diameter of the straws being loaded into the magazine. As also better seen from
FIG. 12
, the discharge conveyor is constituted by two narrow endless belts
73
and
73
′ trained about the drive sheave
71
and idle sheaves
71
′. The drive shaft
93
of the drive sheave
76
extends outwardly of one of the side walls
67
of the bin for coupling to a drive motor (not shown) which is synchronized with the other drives as above-described.
Referring now to
FIGS. 2
,
13
and
14
A, there is shown the construction of the support mechanism for the film roll
17
which feeds the machine. As hereinshown, the support mechanism is comprised of the support shaft
18
secured between pillow blocks
95
disposed inside the machine housing
13
. The support shaft is freely rotated within the pillow blocks
95
and has a connecting free end section
96
extending outside the housing and to which a core chock
97
is removably secured. The core chock
97
is selected to engage the specific film core
98
of the film roll
17
being dispensed. Another core chock
97
′ is secured to a core lock ratchet cap
99
which is secured to the threaded free end
100
of the free end section
96
of the support shaft
18
whereby to clamp the film core
98
between the chocks
97
,
97
′. The ratchet cap
99
is provided with an internal ratchet connection
101
which ensures proper clamping pressure on the core to prevent slippage and the cap from disconnection during high-speed operation of the film roll
17
. As can be appreciated, as the film roll becomes smaller and smaller in diameter, the speed of the shaft increases. However, to control the speed of the shaft to maintain proper tension on the film, there is provided the tension roller
24
, which is displaceable in the arcuate slot
25
and this tension roller
24
is connected to a tension control pivot arm
102
which has a brake shoe
103
for releasable engagement with a brake hub
104
which is secured to the support shaft
18
, as can be seen from
FIGS. 13 and 14A
. The tension roller
24
is displaceable in the arcuate slot
25
on a pivot connection
105
located adjacent the brake hub
104
. Accordingly, the weight of this pivot arm
102
will maintain the tension roller biased downwardly within the arcuate slot
25
against the film strip
21
. As the machine drive slows down, the film roll has a tendency to keep turning at a higher speed and this will cause the tension roller
24
to start moving down within the arcuate slot on its pivot
105
causing the steel brake shoe
103
, as shown in
FIG. 14B
, to move against the drum and slow down the speed of the support shaft
18
. A roller
104
is engageable with the brake hub to limit the displacement of the brake shoe
103
.
With the above dispensing mechanism we have found that large thin narrow film rolls of polyolefin co-extruded film structure comprising a sealing layer with a seal initiation temperature lower than 90° C. and a core comprising a mixture of low, medium and/or high density polyethylene and/or polypropylene with an approximate thickness of between 0.5 to 0.7 mil is a suitable film spec for use with this machine. This is a water-proof film on which printed matter can be printed therealong.
With reference to
FIG. 1
, the method of operation of the machine will be briefly summarized. A narrow thin film roll
17
is placed on the support shaft
18
and locked therein by the ratchet cap
99
. The thin film strip
21
is trained about the tension roll
24
, over the idler roll
23
with the drive feed roll
22
having been sprung back. The film then extends in a lower travel path under the loading conveyor
27
between a pair of guide rolls
26
and
26
′. The film is then positioned up on the inlet roll
28
and through the trough former
29
at the end of which the film is folded in half. As shown in
FIG. 2
, one of the draw rolls
30
, herein roll
30
′ has a cam operated mechanism
109
secured thereto to draw the roll
30
′ away from the stationary draw roll
30
to permit threading the folded film strip and more specifically the upper free end edge portions of the opposed side walls of the folded film through the draw rolls. The heat sealing discs
32
are provided with a pneumatic roll separating mechanism, not shown herein, and these are also opened so that both heated rolls
32
′ separate to permit the folded film strip
21
′ to be passed therebetween without engaging the heated rolls. The film is advanced to the first set of wheels
30
during start up. The film will self-feed through the heated section
32
as the machine starts. The loading conveyor pusher arms
60
are also adjusted with respect to the article at the discharge end of the magazine and the machine is ready for operation. The draw rolls
30
are closed so the machine can be started wherein immediately thereafter the sealing discs
32
′ are closed as well as the vertical sealing and severing assembly
36
. This results in some waste of film material and straws at the beginning of the run. However, because both the film and the straws are made of compatible polyolefin materials, they are easy to recycle as there is no need to separate them. As previously described, the straws are ejected by the discharge conveyor
42
into holding bins or discharge conveyors (not shown) for packaging.
As shown in
FIGS. 15 and 16
, there is thus formed a straw which is held captive in a thin film wrapper
12
formed by a narrow folded plastic film strip defining a trough having opposed side walls
12
and
12
′ and between which a straw
11
is held captive between a longitudinal seal
34
formed adjacent elongated top end edges
12
″ of the film side walls
12
′ and transverse end seals
41
formed at opposed ends of the straw
11
.
It is within the ambit of the present invention to cover any obvious modifications of the preferred embodiment of the invention as described herein, provided such modifications fall within the scope of the appended claims.
Claims
- 1. A machine for wrapping drinking straws with a waterproof plastic film, said machine comprising drive means for continuously advancing a narrow thin film strip from a supply means to a wrapper loading and forming means, tension means to maintain a continuous tension on the said film drawn from said supply means, said wrapper loading and forming means having a trough former for folding said advancing film strip into a film trough, insert means for positioning spaced-apart drinking straws into said film trough of said advancing film strip for engagement and conveyance of said drinking straws by said film trough, straw dispensing means for supplying pre-oriented drinking straws to said insert means, sealing means and severing means for heat sealing said film trough about individual ones of said drinking straws and severing said film trough between adjacent ends of said drinking straws to form individually wrapped drinking straws, said trough former having a geometric forming plate defining a tapered bottom wall having an inlet end and progressively merging opposed upright side walls merging to a narrow rear trough section, and film drawing means spaced from said rear trough section for pulling said film through said trough former form a flat condition adjacent said inlet end to a progressively folded trough condition toward said narrow rear trough section.
- 2. A machine as claimed in claim 1 wherein said film trough defines a straw engaging section intermediate said inlet end and said rear through section whereby to frictionally engage a forward end of a straw to convey said straw by said film trough.
- 3. A machine as claimed in claim 2 wherein said film drawing means is constituted by a set of narrow draw rolls in frictional rotating engagement with opposed side walls of said film trough adjacent top edges of said side walls for advancing said film in folded juxtaposition with a straw retained captive between said film side walls under said draw rolls.
- 4. A machine as claimed in claim 1 wherein said geometric forming plate is secured to an adjustable positioning frame to adjust the position thereof relative to an inlet roll positioned adjacent said flat inlet end of said forming plate and said draw rolls.
- 5. A machine as claimed in claim 3 wherein said narrow drive rolls are coupled to a draw roll drive which is synchronized with said drive means and said insert means.
- 6. A machine as claimed in claim 2 wherein said insert means is an endless belt loading conveyor driven between a drive sheave and an idle sheave, said endless belt having flat run sections disposed adjacent a straw discharge end of said dispensing means, said dispensing means being a straw dispensing means and two or more pusher plates secured to said endless belt in spaced apart relationship and disposed a predetermined distance from one another, said pusher plates each having a straw end engaging wall for engaging a straw at said discharge end of said dispensing means.
- 7. A machine as claimed in claim 6 wherein said drive sheave is provided with pusher plate position adjustment means for adjusting the position of said pusher plates dependent on the length of said straws in said dispensing means.
- 8. A machine as claimed in claim 1 wherein said dispensing means is a straw dispensing means comprised of a holding bin having spaced parallel side walls, a front wall, a rear wall and a bottom wall; straw feed and alignment means comprising a discharge conveyor having an endless belt with a friction upper surface for conveying said straws into a positioning throat section to locate said straws in side-by-side parallel spaced relationship, said positioning throat section being defined by a buffer wall retained in spaced parallel relationship with at least a section of said friction upper surface of said discharge conveyor, said buffer wall permitting said straws to align themselves in said side-by-side parallel spaced relationship.
- 9. A machine as claimed in claim 8 wherein said buffer wall is comprised by a plurality of parallel spaced rods secured to a frame in spaced apart relationship and at a predetermined distance therebetween in a common plane disposed substantially parallel to said friction upper surface of said discharge conveyor disposed thereadjacent, and a flexible hollow tubular member disposed about each said rod in a loose spaced relationship therewith, said hollow tubular member having an inner diameter larger than an outer diameter of said rod permitting lateral displacement of said hollow tubular member.
- 10. A machine as claimed in claim 9 wherein said hollow tubular member is a drinking straw.
- 11. A machine as claimed in claim 9 wherein said friction upper surface of said discharge conveyor is constituted by a serrated upper surface formed by a plurality of spaced apart rib formations, said discharge conveyor being constituted by a pair of spaced-apart belt conveyors each trained about a drive and an idle pulley mounted on support rods.
- 12. A machine as claimed in claim 9 wherein said frame is an adjustable frame whereby to position said common plane at a desired position relative to said friction upper surface.
- 13. A machine as claimed in claim 9 wherein said bottom wall has an inclined wall portion for directing straws to a horizontal straw pick-up section of said discharge conveyor.
- 14. A machine as claimed in claim 13 wherein there is further provided a feed conveyor disposed on an incline with said inclined wall portion for feeding straws to said discharge conveyor.
- 15. A machine as claimed in claim 9 wherein said discharge conveyor has a horizontal throat section disposed adjacent said buffer wall and a transverse substantially vertical discharge section extending at an upper end section of a dispensing magazine.
- 16. A machine as claimed in claim 15 wherein said dispensing magazine defines said straw discharge end at a lower end thereof, said magazine having straw restraining walls disposed in spaced parallel relationship for receiving said straws and maintaining them in parallel side-by-side relationship theralong.
- 17. A machine as claimed in claim 16 wherein an outer one of said straw retaining walls is constituted by at least two spaced apart guide plates retained in vertical relationship by adjustable support rods adjustably secured at opposed ends between vertical side frame members, said guide plates being adjustably positioned relative to said vertical discharge section of said discharge conveyor in relation to the outer diameter of said straws.
- 18. A machine as claimed in claim 17 wherein said discharge end is provided with a lower adjustable wall section spaced from said guide plates, said guide plates being brass plates providing a straw engaging surface with a good slip coefficient.
- 19. A machine as claimed in claim 3 wherein said sealing and severing means comprises a set of narrow heat sealing rolls disposed adjacent said narrow draw rolls for effecting a narrow seal between said opposed side walls of said film trough adjacent said top edge thereof and a transverse seal adjacent opposed end of said straw and severing rolls for severing said film trough through said transverse seal between adjacent straw ends.
- 20. A machine as claimed in claim 19 wherein there is further provided discharge conveyor means for discharging wrapped straws from said set of severing rolls.
- 21. A machine as claimed in claim 19 wherein one of said draw rolls is secured to a manual cam operated mechanism for opening said draw rolls to thread a folded upper section of said film strip between said draw rolls, said set of heat sealing rolls having a pneumatic roll separating mechanism, said set of severing rolls being spring-biased against one another.
- 22. A machine as claimed in claim 1 wherein said supply means is comprised of a film strip roll support shaft having core attachment chocks and a core lock ratchet cap for securing a film strip roll on said support shaft, a tension roller secured to a tension control pivot arm having a brake shoe for releasable engagement with a brake hub secured to said support shaft, said tension roller being displaceable in an arcuate guide slot concentric with a pivot connection of said pivot arm, said film strip being trained over said tension roller bearing disposed between said film strip roll and said drive means, said drive means being a drive roll spring-biased against a stationary roll and through which said film strip is disposed for frictional engagement.
- 23. A machine as claimed in claim 22 wherein said core chocks have at least one replaceable chock to adapt to cores of different widths, said ratchet cap having a pair of ratchet plates to prevent over-tightening of said cap on a threaded end of said film strip roll support shaft.
- 24. A machine as claimed in claim 19 wherein said set of narrow heat sealing rolls, said set of transverse severing rolls, and said set of narrow draw rolls are belt driven by said drive means and synchronized together said drive means being a drive roll spring biased against a stationary roll.
- 25. A machine as claimed in claim 1 wherein said plastic film is a co-extruded polyolefin film structure comprising a sealing layer with a seal initiation temperature lower than 90° C. and a core comprising a mixture of low, medium and/or high density polyethylene and/or polypropylene with an approximate thickness of between 0.5 to 0.7 mil.
- 26. A method of wrapping a drinking straw with a thin waterproof plastic film, said method comprising the steps of:i) continuously drawing a narrow thin film strip from a supply roll to a wrapper loading and forming station by drive means, ii) applying a continuous tension to said narrow thin film strip drawn from said supply roll, iii) folding said narrow thin film strip in a trough former to form a film trough having opposed spaced film side walls, iv) inserting spaced-apart drinking straws into said advancing film trough whereby each drinking straw is frictionally engaged and conveyed by said film trough, v) longitudinally sealing a top end portion of said opposed film side walls together and transversely sealing said walls between opposed ends of said spaced-apart drinking straws positioned between said film side walls, vi) transversely severing said folded film in a transverse seal formed between said opposed ends of said drinking straws therein, and vii) discharging individual plastic film wrapped drinking straws.
- 27. A method as claimed in claim 26 wherein said step (iv) comprises conveying individual drinking straws from a straw discharge end of a straw holding bin, and feeding said discharge end with drinking straws oriented in side-by-side parallel relationship.
- 28. A method as claimed in claim 27 wherein said step of feeding said discharge end comprises feeding straws from said holding bin into a positioning throat of a straw alignment mechanism where said straws are held captive and in side-by-side displacement between a friction upper surface of a discharge conveyor and a buffer wall while permitting limited up and down movement of said straws.
- 29. A method as claimed in claim 26 wherein there is further provided the step of slowing the rotational speed of said supply roll by brake means upon detection of a reduction in speed of said drive means to monitor said tension in said narrow thin film strip.
US Referenced Citations (6)