Information
-
Patent Grant
-
6367376
-
Patent Number
6,367,376
-
Date Filed
Monday, June 19, 200024 years ago
-
Date Issued
Tuesday, April 9, 200222 years ago
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Inventors
-
Original Assignees
-
Examiners
- Rada; Rinaldi I.
- Truong; Thanh
Agents
- Breh; Donald J.
- Croll; Mark W.
- Soltis; Lisa M.
-
CPC
-
US Classifications
Field of Search
US
- 053 588
- 053 589
- 053 582
- 100 8
- 100 26
- 100 29
- 100 32
- 100 33 PB
- 226 25
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International Classifications
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Abstract
A strapping machine is provided with a restriction device that helps prevent strapping material, remaining after a break in the material, from being drawn, by gravity or inertia, into the strapping machine slap box. The restriction device also assists in the orderly movement of strapping material through the strapping machine, by being adjustable, by either strap tension or weight, to widen or restrict the strap path as needed.
Description
FIELD OF THE INVENTION
The present invention concerns a novel restriction device for a strapping machine which prevents strapping material, which has either failed to feed or which has broken, from becoming loose and falling into the slack box of a strapping machine.
BACKGROUND OF THE INVENTION
Strapping machines comprise a number of elements that allow for a strap to be fed from a reel to a strapping head and then onto an object to be strapped. Within the strapping machine the strapping material must be fed through a number of elements that allow the strapping material to travel quickly, efficiently, and accurately towards an object to be strapped. In the operation of strapping machines the strap is first propelled in a forward direction towards the item to be strapped and then the strap is pulled around the item and tightened. Means are provided to reverse the direction of strap travel so that strap may be tightened about the object prior to cutting the strap and so that cutting and securing strap can be accomplished with little waste of material. Strap pulled back into the machine during the tightening process is subsequently released, within the strap path, for further strapping. However, because strap can double up when released, which may result in a restriction of its movement, use of these complex strapping machines is often times impeded by a blockage of loose strap.
Because of the nature of the strapping material, and the need for the material to move rapidly through the strapping machine, no single element of these machines generally holds the loose end of the strapping material within the strapping machine. In some present strapping machines, upon the breaking of an end of the strapping material, the leading end of the strap which is left in the strapping machine is subjected to the pull of gravity and inertia during take-up and little, if any, restraint. The strap end, therefore, often falls or coasts from the guiding members of the machine into the slack box of the machine. This action is known as “suck-back” by users of strapping machines. When suck-back occurs, the end of the reel must be retrieved and the strapping machine must be re-threaded. This process is time consuming and causes delays in the strapping process.
Previously, a fixed type of restrictor has been tried in certain strapping machines. The fixed restrictors, which have been placed between the strap gate and the winder (or strap tensioning device) have proven to be effective in preventing suck back, but also simultaneously restrict strap, which is not broken or loose, from proceeding in the strap path after certain normal machine operations. For example, after an unwinding (a common event in a strapping cycle), strap may form a “tear drop” shaped loop. In a machine with a fixed restrictor, strap material in the shape of a tear drop may be prevented from passing through the fixed restrictor because of the inherent doubling up of the thickness of the strap in such a loop. Further, a fixed restrictor may prevent loops of strap from pulling out of the slack box and into the head, for similar reasons.
SUMMARY OF THE INVENTION
In accordance with the present invention, a strapping machine, having a strap restriction device, a winder, a strap gate, and a slack box is provided. The strap restriction device is provided with an upper guide, having a first end and a second end and a lower guide, having a first end and a second end, said first end of said lower guide being rotationally connected to said first end of said upper guide. The upper guide and the lower guide are biased apart by a spring which urges the second end of the upper guide apart from the second end of the lower guide. In a first default position, the second end of the upper guide is generally disposed, by the spring, toward the winder and the second end of the lower guide is generally disposed toward the strap gate. In the first default position, the upper and lower guides form a strapping guide between the winder and the strap gate and restrict the size of the path for the strapping material. Further, the ends of the upper and lower guide in the first default position, together, form a strap path which provides a frictional surface on which the strap may drag. In these ways the restriction device prevents strapping material from falling or coasting into the slack box.
As the guides are spring biased the movement of strap, respectively, beneath or above the lower and upper guide, can change the position of the guides depending on the tension and force applied to the guides by the strap. The lower guide, when forced upward by strap, provides less of a restriction for the strap to travel through allowing for quicker strap speeds. When the upper guide is forced downward by strap, the restriction device provides less restriction below the winder, allowing quicker clean up of looped material. For example, the formation of a loop of material, due to any number of causes, including the winding and subsequent unwinding of strapping material, may cause the upper guide to be forced downward. When the upper guide is forced downward less restriction occurs for strap passage between the guide and the winder, allowing the loop of strap to be more quickly pulled out of the machine. Similarly, a loop between the lower guide and the strap gate is more quickly removed when the guide is forced upward by the strap.
In one embodiment of the present invention the lower guide is divided into two sections along its longitudinal axis and the upper guide is rotationally set between the two section of the lower guide and attached to a strapping machine. The lower guide sections and the upper guide are biased apart at their second ends by a spring such that the upper guide is disposed upward and the two sections of the lower guide are disposed downward. In this manner strap which may travel laterally along the strapping gate, may be more easily guided by the two separate parts of the lower guide.
A more detailed explanation of the invention is provided in the following description and claims and is illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a front elevational view of a strapping machine made in accordance with the principles of the present invention, showing a restriction device in a first default position.
FIG. 2
is an enlarged front elevation view of the restriction device of FIG.
1
.
FIG. 3
is an elevational view of the strapping machine of
FIG. 1
, showing the restriction device in a second position.
FIG. 4
is an enlarged front elevational view of the restriction device of FIG.
3
.
FIG. 5
is an elevational view of the strapping machine of
FIG. 1
, showing the restriction device in a third position.
FIG. 6
is an enlarged front elevational view of the restriction device of FIG.
5
.
FIG. 7
is an elevational view of the strapping machine of
FIG. 1
, showing the restriction device in a fourth position.
FIG. 8
is an enlarged front elevational view of the restriction device of FIG.
7
.
FIG. 9
is a perspective view of another embodiment of the restriction device of the present invention.
DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENT
Referring to the drawings,
FIGS. 1 and 2
show a strapping machine
10
having a winder
12
and a strap gate
14
in a first strapping position with strapping material
15
being fed through strapping machine
10
. A restriction device
16
comprising an upper guide
18
and a lower guide
20
is provided. Upper guide
18
and lower guide
20
are rotationally connected by pin
22
at a first end
18
a
and
20
a
, respectively, to each other and to the strapping machine
10
through wall
11
. The second ends of guide
18
and
20
, upper guide end
18
b
and lower guide end
20
b
, of restriction device
16
are biased apart by a spring (not shown). In a default, at rest position, upper guide
18
is biased upward and upper guide end
18
b
is disposed generally toward winder
12
and lower guide
20
is biased downward and lower guide end
20
b
is disposed generally toward strap gate
14
. In this first default position, strapping material
15
is fed through strapping machine
10
under constant tension, putting little or no pressure on restriction device
16
. As a result, the biasing spring of restriction device
16
is the prevalent force on the upper guide
18
and lower guide
20
of restriction device
16
, biasing upper guide end
18
b
and lower guide end
20
b
apart and toward, respectively winder
12
and strap gate
14
. Restriction device
16
thereby closes the gap
17
between winder
12
and strap gate
14
so that strapping material
15
proceeds from strap gate
14
through to winder
18
utilizing guide ends
18
b
and
20
b
as additional guidance between these elements.
Referring now to
FIGS. 3 and 4
, strapping machine
10
is shown with the leading edge
24
of strapping material
15
in a position between feed wheels
26
and tension wheels
28
. Restriction device
16
, in its first default position, as shown in
FIGS. 1 and 2
, has lower guide
20
and upper guide
16
biased apart, filling gap
17
. Lower guide
20
b
of restriction
16
in conjunction with strap gate
14
provide a drag on strapping material
15
such that the leading edge
24
of the strapping material is stopped from slipping or coasting through feed wheels
26
down to the slack box (not shown). Such a slip, also known as a “suck back” is thus prevented by restriction device
16
of the present invention. Thus, in
FIGS. 1 through 4
, the default position of restriction device
16
is shown to provide a path for strapping material
15
proceeding normally through the strapping machine
10
and to provide a means for stopping the slippage of strapping material
15
into the slack box. Suck back, which requires that the strapping process cease and that strapping material
15
be re-threaded into strapping machine
110
, is thus generally eliminated.
The improvement over fixed restriction devices of the prior art is shown in the ability of restriction device
16
to provide guidance for strapping material
15
and prevent suck back, while allowing the flexibility of allowing feeding of strapping material
15
after unwinding and when an excess of slack strapping material has accumulated in the slack box, both common events. In these conditions, as explained below, lower guide
20
may be pushed upward and upper guide
18
may be pushed downward, by the force of strapping material
15
, to open gap
17
as needed to alleviate strap drag that causes jams.
Referring now to
FIGS. 5 and 6
, strapping machine
10
is shown having an excess of strapping material
15
in a slack box (not shown) and below and about strap gate
14
and winder
12
. In such situations, strapping material
15
is not fed through strapping machine
10
under constant tension. Strapping material
15
may tend to push upward on lower guide end
20
b
, forcing the lower guide to be pushed upward providing a larger gap
17
, reducing feed force requirements and providing a means to eliminate the slack without entanglement of the strapping material
15
.
In another situation, as illustrated in
FIGS. 7 and 8
, after strapping material has been fed through the head (not shown) of strapping machine
10
, and placed around an object to be strapped, the tension wheels
28
of the strapping machine
10
, in association with winder
12
, cause the free end of the loop of strapping material
15
, around the object to be strapped, to be pulled into strapping machine
10
tightening the strapping material
15
about the object to be strapped. After the ends of the strapping material are fastened together, in a manner known in the art, the strapping material
15
is cut, the winder
12
unwinds to allow the rewound material to subsequently be used to strap the next item to be strapped. Feed wheels
26
begin to feed the strapping material again towards the head (not shown). Concurrently, new strapping material
15
has continued to be fed towards strap gate
14
and has collected in the slack box (not shown). Loops of strapping material
15
, as shown in
FIG. 8
, are thereby formed above and below restriction device
16
. The presence of these loops, or “tear drops”, of strapping material force upper guide
18
to be disposed toward the lower guide widening gap
17
. In this manner restriction device
16
has its lowest profile allowing for the freer flow of strapping material
15
such that local jamming incidents are reduced or generally eliminated.
It is to be understood that variations of the shape and size of restriction device
16
may be made without departing from the novel scope of the present invention. For example, in the preferred embodiment of the present invention, shown in
FIG. 9
, a restriction device
29
having a three guiding members, one upper guide
30
, for engagement with winder
12
sandwiched between two lower guides
32
and
34
, for engagement with strap gate
14
are shown, rotationally engaged together, at a first end, by a pin
36
and biased apart by a spring (not shown), in a manner similar to that described above. The use of two lower guides
32
and
34
allows for guidance under conditions of wide lateral movements of strapping material through strap gate
14
.
Although illustrative embodiments of the invention have been shown and described, it is to be understood that various modifications and substitutions may be made by those skilled in the art without departing from the novel spirit and scope of the invention.
Claims
- 1. A strapping machine, having a restriction device, comprising:a winder; a strap gate, disposed operationally apart from said winder; a slack box; an upper guide, having a first end and a second end; a lower guide, having a first end and a second end, said first end of said lower guide being rotationally connected to said first end of said upper guide; said upper guide and said lower guide being biased apart such that said second end of said upper guide is urged apart from said second end of said lower guide, forming a strapping guide between said winder and said strap gate, said second end of said upper guide being disposed toward said winder and said second end of said lower guide being disposed toward said strap gate, in a first default position.
- 2. The restriction device of claim 1, wherein said strapping guide formed by said upper guide and said lower guide is disposed to restrict the size of the gap between said strap gate and said winder to prevent strapping material from falling or coasting into said slack box.
- 3. The restriction device of claim 1, wherein said strapping guide formed by said second end of said upper guide and said second end of said lower guide define a frictional surface to slow falling or coasting strap within said strapping machine.
- 4. The restriction device of claim 1, wherein said lower guide may be forced up or upper guide forced down, in the presence of strap forces, to provide reduced restriction in said strapping machine to prevent strap jamming.
- 5. The restriction device of claim 1, wherein said lower guide is comprised of two parts, said upper guide being rotationally attached between said two parts of said lower guide at said first end, and biased apart from said upper guide at said second end.
- 6. The restriction device of claim 1, wherein said upper guide and said lower guide are biased apart by a spring.
- 7. A strapping machine, having a restriction device, comprising:a winder; a strap gate; a slack box; an upper guide, having a first end and a second end; a lower guide, having a first end and a second end, said first end of said lower guide being rotationally connected to said first end of said upper guide; said upper guide and said lower guide being biased apart by a spring such that said second end of said upper guide is urged apart from said second end of said lower guide, forming a strapping guide between said winder and said strap gate, said second end of said upper guide being disposed toward said winder and said second end of said lower guide being disposed toward said strap gate, in a default position; and, said lower guide being disposed up in the presence of strap forces or said upper guide being disposed down in the presence of strap forces to provide reduced restriction in said strapping machine to prevent strap jamming.
US Referenced Citations (10)