Patent Application
20110067356
The subject matter disclosed herein generally relates to packaging machines. More specifically, the subject invention relates to a packaging machine having an adjustable wand.
Packaging machines typically convey a product or group of products along a pathway, for example, a conveyor. A piece of wrapping material is typically located on the pathway underneath the product. As the product travels along the pathway, am arm, typically called a “wand”, is moved in a predetermined path, lifting a trailing portion of the wrapping material over the product and to the front of the product to form a roughly tubular shape of wrapping material around the product. The desired path of the wand depends on the size and shape of the product or group of products to be wrapped in the material. To change the path of the wand to accommodate products of different shapes and sizes, the packaging machine must typically be stopped, and some intervention by an operator, often in the form of changing parts on the packaging machine, must occur to perform the necessary adjustments to the path of the wand. Stoppage of the machine to perform adjustments results in machine downtime which decreases productivity of the packaging machine, and reduces flexibility of usage of the packaging machine. The art would well receive an adjustable wand for a packaging machine whose path is changeable without stopping the machine or requiring manual intervention by an operator.
Disclosed herein is an arm assembly including a hub movable about a central axis and at least one support operably connected to the hub. At least one arm is operably connected to the at least one support and thereby movable about the central axis in a predetermined path. At least one adjustment mechanism is located at the central axis and is capable of altering the predetermined path during movement of the at least one support about the central axis.
Further disclosed herein is a wrapping machine including a product conveying portion and an arm mechanism disposed at the product conveying portion. The arm mechanism including at least one hub movable about a central axis and at least support operably connected to the at least one hub. At least one arm is operably connected to the at least one support and is thereby movable about the central axis in a predetermined path. At least one adjustment mechanism is located at the central axis and is capable of altering the predetermined path during movement of the at least one support about the central axis.
Further disclosed herein is a method of operating an arm assembly including locating at least one hub at a central axis and moving at least one arm about the central axis in a predetermined path. The at least one arm is operably connected to the at least one hub via at least one support. An adjustment mechanism is engaged thereby altering the predetermined path during movement of the at least one arm about the central axis.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
Shown in
The wrap machine 10 includes one or more wands 26. Each wand 26 extends laterally from a first side 28 toward a second side 30 of the belt 12. Each wand 26 is supported at at least one end by a support 34, the support 34 supported at a hub 32 of the wrap machine 10. The wands 26 illustrated in
To increase flexibility and reduce downtime of the machine 10, a distance 46 of the wand 26 from the axis of rotation 44 is adjustable to accommodate different product sizes and/or shapes. As shown in
Referring again to
Referring again to
In an exemplary embodiment, adjustments to the position of the wands 26 are made between individual products 60 to accommodate the approaching product 60. It is to be appreciated, however, that adjustments to the position of the wands 26 can be made at any time. For example, the position may be adjusted substantially continuously such that the path described is a substantially a constant distance from the product 60 to facilitate more smoothly wrapping the product 60. In some embodiments where the product 60 has a flat top, the path 42 may be a substantially straight line over the top of the product 60. In other embodiments, elliptical paths 42 may be used with elliptical products 60 and irregularly shaped profiles 42 may be utilized for irregularly shaped product 60 if so desired.
At any point in time, a position of each wand 26 can be expressed relative to the axis of rotation 44. As shown in
x=K sin Φ+S cos Φ
and
y=−K cos Φ+S sin Φ
Given a desired position (x,y) of the wand 26, the position (x,y) can be reached by changing the effective length (S) via the adjustment mechanism 48 and by rotation of the hub 32 about the central axis 44. For a particular position (x,y), the effective length (S) of the support 34 is:
S=sqrt(x2+y2−K2)
The angular rotation of the hub 32 is:
Φ=arc sin[(xK+Sy)/(K2+S2)]
or
Φ=arc sin[(Kx+y*sqrt(x2+y2−K2))/(x2+y2)]
An angular position (θ) of the wand 26 is expressed as:
θ=α+Φ
where
α=S/K or sqrt(x2+y2−K2)/K
Utilizing the above equations, given a desired position (x,y) of the wand 26, the necessary effective length (S) and angular rotation (Φ) can be determined. The effective length (S) and angular rotation (Φ) may be utilized by, for example, the controller 58 to drive the wand 26 to a desired position.
As shown in
ΔS=sqrt[(x2−x1)2+(y2−y1)2−K2]
and
ΔΦ=arc sin[(K*(x2−x1)+(y2−y1)*sqrt((x2−x1)2+(y2−y1)2−K2))/((x2−x1)2+(y2−y1)2)]
Further, each leg 62 may be subdivided into sublegs to further define the motion of the wand 26 between, for example, (x1, y1) and (x2, y2). In one example where 32 sublegs are utilized between (x1, y1) and (x2, y2):
x
2
−x
1=32*Δx
and
y
2
−y
1=32*Δy
In one embodiment, as shown in
X=S cos Φ
and
Y=S sin Φ.
For a given position (x, y), the necessary S and Φ are:
S=sqrt(x2+y2)
and
Φ=arc tan(y/x).
Similarly, to move the wand 26 between positions (x1, y1) and (x2, y2):
ΔS=sqrt((x2−x1)2+(y2−y1)2)
and
ΔΦ=arc tan((y2−y1)/(x2−x1)).
It is to be appreciated that use of the adjustment apparatus is not limited to wrapping machines 10. For example, the wands 26, or the supports 34 themselves, may be configured to pick up a product at a first location and move the product to a second location via rotation about the axis of rotation 44 and/or moving the supports 34 to change position of the wands 26.
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims
