Information
-
Patent Grant
-
6532722
-
Patent Number
6,532,722
-
Date Filed
Wednesday, July 18, 200123 years ago
-
Date Issued
Tuesday, March 18, 200321 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Welsh & Katz, Ltd.
- Croll; Mark W.
- Breh; Donald J.
-
CPC
-
US Classifications
Field of Search
US
- 053 589
- 053 3759
- 053 DIG 2
- 100 33 PB
-
International Classifications
-
Abstract
A strapping head for a strapping machine of the type having a feed assembly and a chute that is configured to position, tension and seal strapping material around a load, includes a body and an anvil mounted to and movable relative to the body. A sealing member is disposed in the anvil for oscillating movement. A drive is operably connected to the sealing member and movable relative to the body to provide oscillating movement to the sealing member. First and second courses of strapping material overlie one another adjacent the sealing member, and oscillation of the sealing member effects a seal of the first and second courses of strapping material to one another.
Description
BACKGROUND OF THE INVENTION
Strapping machines are well known in the art. Typically these machines are used for securing straps around loads. One type of strapper is used with a plastic or polymeric strap and is a stationary arrangement in which the strapper is included as part of an overall manufacturing or packaging system.
A typical strapper includes a frame to which various components are mounted. A chute is mounted to the frame through which the strapping material is fed around a load. A strapping head and a drive or feed mechanism are mounted to the frame. The strapping material is fed from a source, by the feed assembly, through the strapping head. The strapping material traverses around the chute and back to the strapping head. Various guides may be mounted to the frame to provide a path for the strap. For example, a guide may be positioned at the feed assembly to guide the strap into feed wheels. A guide may also be positioned between the feed assembly and the strapping head to provide a strap path from the feed assembly to the head.
The strapping or welding head provides a number of functions. First, the strapping head includes a gripper having one or more gripper portions that grip the strap during the course of a strapping operation. The strapping head also includes a cutter to cut the strap from a strap source or supply. Last, the strapping head includes a sealer to seal an overlying course of strapping material onto itself. This seal is commonly referred to as a weld and is effected by heating one course of the strap by use of a vibrating element.
Known strapping heads include a body and an anvil between which the courses of strap materials traverse during a strapping operation and between which the strapping material courses are held during the welding operation. The gripper is mounted within the body and is operably connected to a camshaft having a plurality of cams thereon. Cam lobes move the gripper into and out of engagement with the strapping material to effect the necessary gripping functions during the strapping operation. The anvil is maintained rigidly against the body and a vibrating element within the body oscillates or vibrates thus creating friction and heat to effect the weld.
The vibrating element is disposed within the strapping head body. During the course of welding the strapping material onto itself, the gripper must maintain a sufficient pressure on the strap, against the anvil, to assure that the strap does not slip as the vibrating element vibrates (i.e., as the seal is made). To this end, complex linkages are required to assure that the gripper (mounted within the body) maintains contact with the strap (and the anvil) when the vibrating element is actuated. As such, strapping heads can be of complex, construction and design, particularly when large tensions are required in the strap to maintain the load bundled.
Accordingly, there exists a need for a simplified welding or strapping head for use in a strapping machine. Desirably, such a welding head eliminates the need for complex linkages otherwise required to maintain the gripping portion in contact with the strap (and the anvil) when the vibrating element is actuated. More desirably, such a strapping head is of a compact design. Most desirably, in such a strapping head, the vibrating element is removed from the strapping head body.
BRIEF SUMMARY OF THE INVENTION
A strapping head is used in a strapping machine of the type having a feed assembly and a chute. The strapping machine is configured to position, tension and seal strapping material around a load. The strapping head is positioned adjacent the chute.
The strapping head includes a body and an anvil mounted to and movable relative to the body. In a present embodiment, strapping head includes a side plate pivotally mounted to the body and the anvil is fixedly mounted to the side plate.
The strapping head further includes a gripper assembly disposed in the body and a sealing member disposed in the anvil for oscillating movement. A drive is operably connected to the sealing member to provide oscillating movement to the sealing member.
First and second courses of strapping material overlie one another in the strapping head, adjacent the sealing member. Oscillation of the sealing member effects a seal of the first and second courses of strapping material to one another.
In a preferred configuration, the sealing member drive is mounted to the side plate for movement with the anvil. To effect oscillation, the drive includes an eccentric drive element and the sealing member include a coupling portion for coupling with the eccentric drive element. The eccentric drive element can be configured as an eccentric shaft and the coupling portion can include a non-circular receiving opening for receiving the shaft. In such a configuration, a bearing is disposed on the shaft for contact with the receiving opening.
To accommodate the sealing member, the anvil includes a channel formed therein. Bearings can be disposed within the channel for receiving the sealing member.
The strapping head can include a platen for maintaining the first and second courses of strapping material compressed against the sealing element. The platen can be disposed between first and second grips within the gripper assembly, with the cutter disposed adjacent the platen.
These and other features and advantages of the present invention will be apparent from the following detailed description, in conjunction with the appended claims.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The benefits and advantages of the present invention will become more readily apparent to those of ordinary skill in the relevant art after reviewing the following detailed description and accompanying drawings, wherein:
FIG. 1
is a perspective view of an exemplary strapping machine having a strapping head with a vibrating member anvil embodying the principles of the present invention;
FIG. 2
is a schematic view of the exemplary strapping machine showing a load positioned in the chute region, and the strap source feeding the machine via a feed assembly;
FIG. 3
is a side perspective illustration of the strapping head, illustrating the weld motor mounted to the strapping head side plate;
FIG. 4
is a bottom perspective illustration of the anvil and vibrating member;
FIG. 5
is a bottom view of the anvil and vibrating member of
FIG. 4
; and
FIG. 6
is a cross-sectional view of the strapping head taken along lines
6
—
6
of FIG.
3
.
DETAILED DESCRIPTION OF THE INVENTION
While the present invention is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described a presently preferred embodiment with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiment illustrated.
It should be further understood that the title of this section of this specification, namely, “Detailed Description Of The Invention”, relates to a requirement of the United States Patent Office, and does not imply, nor should be inferred to limit the subject matter disclosed herein.
Referring to the figures and in particular
FIG. 1
, there is shown a strapping machine
10
, having a strapping or weld head
12
with a vibrating member anvil
14
, embodying the principles of the present invention. The machine
10
includes, generally, a frame
16
, a strap chute
18
and a feed assembly
20
. A controller
22
provides automatic or semi-automatic operation and control of the strapper
10
. The weld head
12
includes generally, a body
24
and an anvil
26
. A gripper assembly
28
and a cutter
30
are carried by the body
24
. Preferably the cutter
30
is disposed within the gripper assembly
28
.
Referring to
FIG. 3
, the anvil
26
is movably mounted to the strapping head body
24
. In a preferred arrangement, the anvil
26
is fixedly mounted to a side plate
32
that moves relative to the body
24
. Preferably, the side plate
32
(and thus the anvil
26
) pivots about and relative to the body
24
. The anvil
26
moves between a closed position, in which the strap S is grasped, cut and welded, and an open position in which the strap S is allowed to freely pull from the head
12
following a strapping operation. The side plate
32
(and thus the anvil
26
) can be pivotally mounted to the strapping head body
24
by a pivot pin
34
.
Referring to
FIG. 6
, pivotal movement of the plate
32
and anvil
26
can be provided by, for example, a cam
36
mounted on a camshaft
38
disposed within the strapping head body
24
. The shaft
38
can be have other cams
40
,
42
,
44
(described below) thereon for moving portions of the gripper assembly
28
and cutter
30
into and out of engagement with the strap S. The plate cam
36
engages the side plate
32
, thus pivoting the side plate
32
and anvil
26
outwardly, away from the body
24
, into the open position. The side plate
32
is biased, by a biasing member such as a spring (not shown), to the closed position. A motor
46
drives the camshaft
38
.
The gripper assembly
28
includes at least two gripping portions (referred to as grips). In a current embodiment, the gripper assembly
28
includes an end grip
48
and a loop grip
50
. Preferably, a platen
52
or like element is disposed adjacent or within the gripper
28
that is brought into contact with the strap S during the welding operation, as will be described in more detail below. In a current embodiment, the platen
52
is positioned between the end grip
48
and the loop grip
50
, adjacent the cutter
30
.
Referring now to
FIGS. 3-5
, unlike known strapping heads, the present strapping head
12
utilizes a sealing member, such as the illustrated vibrating member
54
that is disposed in the anvil
26
. That is, while known strapping heads have the vibrating or welding element disposed within the head body, the present head
12
positions the vibrating member
54
within moving anvil
26
. The vibrating member
54
includes a welding end
56
having a weld pad or weld region
58
and a coupling end
60
.
A motor
62
is operably connected to the vibrating member
54
to effect, the necessary vibrations or oscillations of the member
54
. In a current combodiment, the motor
62
is mounted to the side plate
32
, and thus moves or pivots with the anvil
26
. In this manner, the motor
62
is fixedly mounted relative to the anvil
26
and vibrating member
54
.
The vibrating member
54
is disposed within an open channel
64
in the anvil
26
. The weld pad portion
58
of the member
54
contacts the strap S during the welding operation. The vibrating member
54
oscillates, in a generally reciprocating manner, in the direction indicated by the double headed arrow at
66
within the channel
64
.
As best seen in
FIG. 5
, to effect oscillation of the vibrating member
54
, the motor
62
includes an eccentric drive element, such as the exemplary eccentric drive shaft
68
extending through a receiving opening
70
in the vibrating member coupling end
60
. A bearing
72
is mounted to the shaft
68
. The eccentric shaft
68
is configured such that the axis of rotation A
1
is off-center of the shaft axis A
2
.
The receiving opening
70
is a non-circular opening. The opening
70
is elongated in a direction (indicated at
74
) transverse to the reciprocating movement direction
66
of the member
54
. The dimension of the opening
70
in the reciprocating movement direction (as indicated at
76
) is about the same as the diameter D of the eccentric shaft
68
. In this manner, the shaft
68
(having the bearing
72
fitted thereto) makes a tight fit in the opening
70
in the direction of movement
66
, but has dimensional freedom in the direction transverse to the reciprocating direction
66
. To this end, as the shaft
68
rotates eccentrically, it imparts reciprocating (i.e., linear) motion to the vibrating member
54
, but does not impart any side-to-side motion to the member
54
.
Those skilled in the art will appreciate that other means to drive the vibrating member
54
can be employed. For example, linkages, cogs, gears and the like can be used to impart vibrating motion to the member
54
. Likewise, other electromechanical, mechanical or electrical arrangements can be used. All such other means are within the scope and spirit of the present invention.
Referring now to
FIG. 5
, bearings
78
are disposed between the vibrating member
54
and the walls
80
defining the channel
64
. In a current embodiment, needle type bearings
78
are used to permit free reciprocating motion or oscillation
66
of the vibrating member
54
and to reduce friction between the vibrating member
54
and the channel walls
80
. The bearings
78
also ensure that movement of the member
54
within the channel
64
is restricted to reciprocating movement, rather than side-to-side movement.
As set forth above, the vibrating member
54
includes a weld pad or weld region
58
. This is the region that contacts the strap S during vibration to thus effect the weld or seal. In a current embodiment, the weld pad
58
is formed by cuts, (e.g., serrations) as indicated at
82
in the weld pad
58
. Those skilled in the art will recognize that there are various configurations and structures that can be used to effect the weld region
58
.
Operation of the sealing head
12
will now be described with reference to FIG.
6
. Strapping material S is fed into the strapping head
12
through opening
84
, traverses through the strapping head
12
, through the chute
18
and around the load L, and returns to the strapping head
12
, entering through second opening
85
. The first course of strapping material S
1
stops at a predetermined location in the strapping head
12
, as indicated at
86
. This stop
86
is provided by restricting the height h of the path through the head
12
at this point to about 1-½ times the thickness of the strap S.
Once the first course of strapping material S
1
reaches the stop
86
, a sensor (not shown) signals the controller
22
to stop strap feed. The end grip
48
is then moved toward the anvil
26
by contact of the cam
40
with the grip
48
. Once the end grip
48
is in place, the strap S is secured between the grip
48
and a gripper pad
49
on the anvil
26
. In a preferred configuration, the gripper pad
49
is replaceable. The strap S is tensioned by, for example, retraction of the strap S.
When a desired tension in the strap S is reached, the loop grip
50
moves into engagement with the strap S and anvil
26
, again by engagement of the cam
42
with the grip
50
. At this point in time, both the end grip
48
and loop grip
50
are fully engaged with the strap S secured between the respective grips
48
,
50
and gripper pads
49
in the anvil
26
.
The cutter
30
and platen
52
then move toward the anvil
26
by engagement of the cam
44
with the platen
52
. The cutter
30
cuts one course strap S to separate the strap S from the strap supply P. At the same time, the platen
52
presses the strap S against the anvil
26
.
The weld motor
62
is then actuated to oscillate the weld member to effect a weld in the strap material S at the area generally indicated at
88
. After a predetermined period of time during which acceptable weld strength is reached, and after cooling, the end grip
48
and loop grip
50
as well as the platen
52
and cutter
30
are moved away from the anvil
26
(by further rotation of the camshaft
38
) and the side plate
32
anvil
26
pivot outwardly, away from the body
24
. This releases the strap S from the head
12
.
The load L is then removed from the chute
18
region, and a new load is set in place for strapping. The side plate
32
and anvil
26
are then moved back into the closed position and strapping material S is again fed through the strapping head
12
, into the chute
18
around the load L and back to the strapping head, to repeat the strapping procedure.
In the present disclosure, the words “a” or “an” are to be taken to include both the singular and the plural. Conversely, any reference to plural items shall, where appropriate, include the singular.
From the foregoing it will be observed that numerous modifications and variations can be effectuated without departing from the true spirit and scope of the novel concepts of the present invention. It is to be understood that no limitation with respect to the specific embodiments illustrated is intended or should be inferred. The disclosure is intended to cover by the appended claims all such modifications as fall within the scope of the claims.
Claims
- 1. A strapping head for a strapping machine of the type having a feed assembly and a chute, the strapping machine configured to receive first and second courses of associated strapping material, position, tension and seal the strapping material around a load, the strapping head configured for positioning adjacent the chute, the strapping head comprising:a stationary body; an anvil mounted to and movable relative to the body; a gripper assembly disposed in the body; a sealing member disposed in the anvil for oscillating movement; a side plate pivotally mounted to the stationary body; and a drive fixedly mounted to the side plate and operably connected to the sealing member to provide oscillating movement to the sealing member, wherein the anvil is mounted to the side plate, and wherein the first and second courses of strapping material are positioned to overlie one another adjacent the sealing member, and wherein oscillation of the sealing member effects a seal of the first and second courses of strapping material to one another.
- 2. The strapping head in accordance with claim 1 wherein the drive includes an eccentric drive element and the sealing member includes a coupling portion for coupling with the eccentric drive element.
- 3. The strapping head in accordance with claim 2 wherein the eccentric drive element is an eccentric shaft and the coupling portion includes a non-circular receiving opening for receiving the shaft.
- 4. The strapping head in accordance with claim 3 wherein the shaft includes a bearing disposed thereon for contact with the receiving opening.
- 5. The strapping head in accordance with claim 1 wherein the anvil includes a channel therein for receiving the sealing member.
- 6. The strapping head in accordance with claim 5 including bearings disposed within the channel for receiving the sealing member.
- 7. The strapping head in accordance with claim 1 including a platen for maintaining the first and second courses of strapping material compressed against the sealing element.
- 8. The strapping head in accordance with claim 7 wherein the platen is disposed between first and second grips within the gripper assembly.
- 9. The strapping head in accordance with claim 8 including a cutter disposed adjacent the platen.
- 10. A strapping head for a strapping machine of the type having a feed assembly and a chute, the strapping machine configured to receive first and second courses of associated strapping material, position, tension and seal the strapping material around a load, the strapping head configured for positioning adjacent the chute, the strapping head comprising:a stationary body; a side plate movably mounted to the stationary body; an anvil fixedly mounted to the side plate and movable relative to the body with the side plate; a gripper assembly disposed in the body; a sealing member disposed for vibrating movement in the anvil; and a drive fixedly and directly mounted to the side plate, the drive being movable with the side plate and fixed relative to the anvil, the drive being operably connected to the sealing member, wherein first and second courses of strapping material are positioned to overlie one another adjacent the sealing member, and wherein vibration of the sealing member effects a seal of the first and second courses of strapping material to one another.
- 11. The strapping head in accordance with claim 10 wherein the drive includes an eccentric drive shaft and the sealing member includes a coupling portion having a slotted opening for receiving the eccentric drive shaft.
- 12. The strapping head in accordance with claim 11 including a bearing disposed on the eccentric drive shaft for contact with the receiving opening.
- 13. The strapping head in accordance with claim 10 wherein the anvil includes a channel therein for receiving the sealing member, and including bearings disposed within the channel for contacting the sealing member.
- 14. The strapping head in accordance with claim 10 including a platen for maintaining the first and second courses of strapping material compressed against the sealing element.
- 15. The strapping head in accordance with claim 14 wherein the platen is disposed between first and second grips within the gripper assembly.
- 16. The strapping head in accordance with claim 15 including a cutter disposed adjacent the platen.
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Number |
Name |
Date |
Kind |
4079667 |
Lems et al. |
Mar 1978 |
A |
4378262 |
Annis, Jr. |
Mar 1983 |
A |
4479834 |
Kobiella |
Oct 1984 |
A |
4776905 |
Cheung et al. |
Oct 1988 |
A |