Patent Application
20080115979
In blow molding operations for the production of bottles, it is often desirable to periodically weigh sample bottles after they are produced on a manufacturing line. This information may be used to determine whether too much or too little resin is being used in each bottle. If the bottles are being produced with too little resin, the bottles may not satisfy agreed-upon bottle specifications. On the other hand, if the bottles are being produced with too much resin, the production cost associated with each bottle may be higher than necessary due to the extra resin content of the bottles. Accordingly, operators may use the information obtained from weighing the bottles to make any adjustments necessary to ensure that the manufacturing process is cost-efficient and results in the production of compliant bottles.
Currently, it is common for production operators to periodically weigh sample bottles selected from a manufacturing line by hand. This process is inefficient and labor intensive. Some automated item weighing mechanisms also exist, but these mechanisms are often expensive and difficult to add to existing manufacturing lines. These current item weighing mechanisms typically also require extensive modifications in the event of a product changeover (in which the manufacturing line is modified to produce a different bottle). Accordingly, there is a need for improved weighing mechanisms (for bottles or other items) that address one or more of the problems noted above.
Various embodiments of the invention are directed to an item weighing apparatus for weighing a first item in a series of items traveling on a conveyor in which a first item is downstream of a second item of the series of items (e.g., relative to the conveyor's direction of motion). In various embodiments, the item weighing apparatus comprises: (1) a scale; (2) an item repositioning mechanism that is adapted to move the first item from the conveyor into weighing engagement with the scale; and (3) a braking mechanism that is adapted to limit the forward progress of the second item while the item repositioning mechanism moves the first item from the conveyor into weighing engagement with the scale, and to thereby prevent the second item from passing the first item while the first item is in weighing engagement with the scale.
In other embodiments, the first and second items are in an immediate sequential relationship to each other on the conveyor; and the item weighing apparatus comprises: (1) a scale comprising a weighing surface, the scale being adapted to weigh one or more items disposed on the weighing surface; and (2) an item repositioning mechanism that is adapted for: (A) sliding the first item from a position adjacent a top surface of the conveyor onto a weighing surface of the scale; and (B) after the scale weighs the first item, sliding the first item from the weighing surface of the scale back to a position adjacent the top surface of the conveyor. In particular embodiments, the system is adapted to prevent the second item from passing the first item while: (A) the item repositioning mechanism slides the first item from a position adjacent a top surface of the conveyor onto a weighing surface of the scale; (B) the scale weighs the first item; and/or (C) the item repositioning mechanism slides the first item from the weighing surface of the scale back to a position adjacent the top surface of the conveyor.
Particular embodiments of the invention are directed to a method of weighing a first item in a series of items traveling on a conveyor, wherein the first item is downstream of a second item of the series of items, relative to a direction of motion of the conveyor. In various embodiments, the method comprises the steps of: (A) restricting the forward movement of the second item; and (B) while restricting the forward movement of the second item: (1) diverting the first item from the conveyor so that the first item is in weighing engagement with a scale; (2) after the step of diverting the first item so that the first item is in weighing engagement with a scale, and while the first item is in weighing engagement with the scale, weighing the first item; and (C) after the step of weighing the first item, moving the first item back onto the conveyor.
Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
The present invention now will be described more fully with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, this invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.
An item weighing apparatus according to a particular embodiment of the invention is shown in
In a particular embodiment, the braking mechanism 120 includes a brake 125 that may, for example, be substantially planar and that may be mounted so that a front face of the brake 125 is in a substantially vertical orientation and faces items traveling on the conveyor 105 past the brake mechanism 120. The brake 125 is pivotably mounted adjacent the conveyor 105 so that the brake 125 may selectively pivot about a pivot point 127 that is disposed adjacent an upstream end of the brake 125.
The braking mechanism 120 of
For example, in
In a particular embodiment, when the brake 125 is in a disengaged orientation (see
In particular embodiments of the invention, the item weighing apparatus 100 includes a scale 130 that is positioned adjacent the conveyor 105 and that is adapted to weigh one or more items traveling on the conveyor 105 (e.g., items A-E) when the items are positioned on a weighing surface of the scale 130. The scale 130 is preferably positioned so that the scale's weighing surface (which is preferably a substantially planar, substantially horizontal surface) is at about the same height as the upper surface of the conveyor 105. This serves to facilitate sliding items from the conveyor's upper surface to the scale's weighing surface.
In particular embodiments, the scale 130 is positioned so that the scale's weighing surface is immediately adjacent a lateral side of the conveyor 105. In other embodiments, the scale 130 is positioned so that the scale's weighing surface is spaced apart from a lateral side of the conveyor 105. In such an embodiment, a substantially planar, substantially horizontal, low-friction “slide plate” may be positioned so that it extends between the conveyor's upper surface 105 and the scale's weighing surface. The slide plate preferably provides a low-friction bridge between the conveyor's upper surface 105 and the scale's weighing surface.
In various embodiments, the item weighing apparatus 100 further includes an item repositioning mechanism 140 that is adapted for moving items: (A) from the top surface of the conveyor 105 to a weighing surface of the scale 130; and (B) from the weighing surface of the scale 130 back onto the top surface of the conveyor 105. In particular embodiments, the item repositioning mechanism 140 includes an item positioning assembly 142 that includes a first wall 143 (which is preferably a substantially planar, substantially vertical wall), and a second wall 144 (which is also preferably a substantially planar, substantially vertical wall). As shown in
In various embodiments, a substantially horizontal bridge portion (not shown) extends from a top surface of the first wall 143 to a top surface of the second wall 144. Accordingly, in such an embodiment, the item positioning assembly 142 is substantially U-shaped and inverted. In other embodiments, one or more other types of structural members are used to maintain the second wall 144 in a pre-determined spaced-apart relationship with the first wall 143. However, it should be understood that, in alternative embodiments, the first and second walls 143, 144 may be adapted to move relative to one another.
As shown in
In particular embodiments, the item weighing apparatus 100 includes a stop mechanism 150 that is adapted to selectively prevent items from moving past a pre-determined position on the conveyor 105 (e.g., from moving substantially past the item positioning assembly 142). In particular embodiments, the stop mechanism 150 comprises a substantially planar, substantially vertically-oriented stop 151 that is preferably oriented so that it is substantially perpendicular to the conveyor's direction of travel.
In various embodiments, the stop mechanism 150 further comprises an actuator that is adapted for selectively moving the stop 151 into (and out of) the path of items traveling on the conveyor 105. For example, in the embodiment shown in
As noted above, in particular embodiments, the item weighing apparatus 100 includes a plurality of sensors 110, 112, 114, 116, 149, each respective one of which is adapted for detecting the presence of one or more items adjacent the respective sensor. In one embodiment, the item weighing apparatus 100 includes: (1) a first sensor 110 that is positioned to sense the presence of items moving on the conveyor 105 immediately adjacent the braking mechanism 120; and (2) a second sensor 112 that is positioned to sense the presence of items moving on the conveyor 105 as they begin to pass between the item repositioning mechanism's first and second walls 143, 144; (3) a third sensor 114 that is positioned to sense the presence of items moving on the conveyor 105 as they begin to move past the item repositioning mechanism's first and second walls 143, 144; (4) a fourth sensor 116 that is positioned to sense the presence of items downstream of the third sensor 114 (relative to the motion of the conveyor); and (5) a fifth (“scale”) sensor 149 that is positioned to sense the presence of items on the scale 130. It should be understood that, in other embodiments of the invention, the item weighing apparatus 100 may include more or fewer sensors than those described above.
In particular embodiments, the item weighing apparatus 100 includes a control system (e.g., a computerized control system comprising at least one computer processor and a memory for storing computer-executable instructions to be executed by the at least one computer processor). In particular embodiments, the control system is adapted for controlling the operation of the braking mechanism 120, the scale 130, the item repositioning mechanism 140, and/or the stop mechanism 150. In particular embodiments, the control system is adapted for receiving data from the item weighing apparatus' various sensors 110, 112, 114, 116, 149 and for controlling the operation of the braking mechanism 120, the scale 130, the item repositioning mechanism 140, and the stop mechanism 150 based, at least in part, on information obtained from the item weighing apparatus' various sensors 110, 112, 114, 116, 149. The operation of various embodiments of the item weighing apparatus 100 is described below.
The operation of an item weighing apparatus 100 according to a particular embodiment of the invention is shown in
As shown in
Next, as shown in
Next, as shown in
As shown in
Next, in response to the control system determining (e.g., via information obtained from the second sensor 112) that an item (here, item D) has moved into contact with the stop 151 and is positioned between the item positioning assembly's first and second walls 143, 144, as shown in
Next, while maintaining the brake 125 in the braking position, the control system causes the item repositioning mechanism 140 to move the item positioning assembly 142 toward the scale 130. As a result, the first wall 143 of the item positioning assembly 142 engages a lateral side of item D and slides item D onto the scale's weighing surface (see
In response to item D being moved onto the scale's weighing surface, the scale sensor 149 is activated which, in turn, causes the control system to take a weight reading from the scale 130. This weight reading reflects the weight of item D.
As shown in
In response to the control system determining that the weighed item (here, item D) has been placed back onto the conveyor 105 (which may be determined based on the movement of the item positioning assembly 142), the control system moves the stop 151 into a retracted position in which the stop 151 does not substantially obstruct the path of items traveling on the conveyor 105 (see
Next, the system may weigh the immediate next upstream item (here, item E) by simply repeating the techniques described above in regard to item D for item E. This process is shown (up to the point at which item E is positioned between the first and second walls 143, 144 of the item positioning assembly 142) in
As may be understood from the above example, various embodiments of the item weighing apparatus 100 may be used to weigh items while maintaining their original relative positions on the conveyor 105 (e.g., without changing the original order of the items on the conveyor 105). However, it should be understood that similar techniques may be used to allow items upstream of a particular item that is being weighed to pass the particular item as it is being weighed by the item weighing apparatus 100. This may be done, for example, by simply moving the brake 125 and stop 151 out of the path of items traveling on the conveyor 105 as the particular item is being weighed.
In this “pass through” embodiment, before moving the weighed item from the scale 130 onto the conveyor 105, the control system may move the brake 125 into the braking position and use the second and third sensors 112, 114 to determine when all items have moved out of the lateral path of the item positioning assembly 142. In response to making this determination, the control system may then cause the item positioning assembly 142 to move the weighed item back onto the conveyor 105. This technique serves to prevent the item repositioning mechanism 140 from pushing items off of the conveyor 105 as the item repositioning mechanism 140 moves weighed items onto the conveyor 105.
In various embodiments of the invention, in response to receiving weight data for a particular item from the scale 130, the control system saves this weight data (e.g., along with an appropriate date and time stamp) in a memory (e.g., within a database) associated with the item weighing apparatus 100. In various embodiments, this information may be used to adjust machinery producing the items so that the weight of the items is within a target weight range. This weight information may also be used later to evaluate the performance of the operators who are operating the machinery.
The above techniques are especially useful in the production of lightweight plastic items, such as plastic containers. However, it should be understood that such techniques may be used in conjunction with a wide variety of other items, such as food items.
Many modifications and other embodiments of the invention will come to mind to one skilled in the art to which this invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Accordingly, it should be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended exemplary concepts. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for the purposes of limitation.
