The manufacture of certain products, such as roof shingles, or other generally planar products, include a conveyor that moves the product, such as a length of material, through various manufacturing stages. In the case of manufacturing roofing shingles, a felt strip is treated and adhesive material and granulated particles are applied thereto. The elongate strip eventually passes through a cutter to cut the felt material into standard lengths after which a delivery conveyor transfers the cut shingles to a packaging station. The manufacturing cost for such shingles can be minimized by increasing the conveyor speed. The limiting factor for conveyor speed, in many such manufacturing processes, is at the packaging end where the fast moving product on a delivery conveyor must be stopped and stacked for packaging. Where the speed of the delivery conveyor is very high and the moving product is stopped in a short distance, the product may be damaged during the packaging operation.
One method of increasing conveyor speed is to divert every other product on the conveyer to a second packaging station. Conceptually, the provision of two packaging stations permits the conveyor speed to be doubled, without altering the product speed at the packaging station. Providing two packaging stations, however, required a diverter in which every other product on the conveyor is diverted to a secondary delivery conveyor that leads to a secondary packaging station. Usually, the secondary delivery conveyor is positioned above or below the primary delivery conveyor and the diverter diverts every other product either upwardly or downwardly to the secondary delivery conveyor.
A speed up conveyor usually follows the cutter to provide a gap between the cut products, and the diverter follows the speed up conveyor. In one form of prior art diverters, a gap is provided at the end of the speed up conveyor and before the beginning of the primary delivery conveyor leading to the primary packaging station. The belts move with sufficient speed to provide enough kinetic energy to the product to cause it to span the gap from the speed up conveyor to the primary delivery conveyor and every other product is allowed to span the gap. The diverter includes a wheel that is pivoted downward from above into the gap that nudges every other product to the secondary delivery conveyor below the primary delivery conveyor thereby diverting every other product.
In another prior art diverter positioned after a speed up conveyor includes a plurality of spaced apart belts. A plurality of moveable ramps are intermittently projected between the belts and intercept every other product moving across the spaced apart belts. When the ramps are projected between the belts, the succeeding product is moved upwardly along the ramp to a secondary delivery conveyor positioned above the primary delivery conveyor. When the ramps are withdrawn, the alternate product is moved to the primary stacking station.
Although the diverter makes possible the use of a secondary packaging station, the diverter mechanism requires time to operate and as a result products that are to be separated by the diverter must be sufficiently spaced on the conveyor to permit the diversion mechanism to be moved in place before the arrival of the next product. In order to provide the desired spacing between products, it is often necessary to provide a series of speed up conveyors. The provision of accelerating conveyors, however, increases the space requirements of the conveyors and increases the product speed that must be decelerated prior to packaging. It is desirable, therefore, that the diverter require a minimum amount of spacing between adjacent products to thereby require a minimum increase in product speed and a minimum lengthening of the conveyor.
It is common to use servo motors in diverters because of the accuracy with which they can be controlled and the rapidity of their movements. Even so, existing diverters require that the diversion elements, such as ramped surfaces or wheels that redirect a moving product from a primary delivery conveyor to a secondary line be moved into place after the trailing edge of a first product has passed and prior to the arrival of a leading edge of the next product. Similarly, after a second product has been diverted to a secondary delivery conveyor, the ramps or wheels that diverted the second product must be removed from position after the trailing end of the second product has passed and before the leading edge of the third product arrives. The time required to insert or remove a diversion element is short; however it significantly increases the gap required between two successive products. It would be desirable therefore, to provide a short gap diverter for which no time would be required to inject the diverting elements following the passage of the trailing edge of a first product and prior to the arrival of the leading edge of a second product onto the diverting device. In such a case, the gap between successive products need not be any longer than the length of the working parts of the diverter.
Briefly, the present invention is embodied in a short gap diverter for a conveyor system conveying a product having a leading edge and a trailing edge. The conveyor includes an input conveyor, a primary delivery conveyor opposite the input conveyor, a transit conveyor between the input conveyor and the primary delivery conveyor, and a secondary delivery conveyor positioned above the primary delivery conveyor. The transit conveyor may be the first section of a delivery conveyor that leads to a packaging station.
In accordance with the invention, the upper surfaces of the input conveyor, the transit conveyor, and the primary delivery conveyor all define a first plane and the upper surface of the upper delivery conveyor defines a second plane that is angled at a first angle with respect to the first plane and intersects the first plane with the intersection falling near a leading end of the transit conveyor. It is desirable that the first angle between the first and second plane define a small angle, preferably between ten and fifteen degrees.
The invention further requires a moveable first finger having a length, an outer end, and an upper surface. The first moveable finger is preferably mounted on the transit conveyor between two parallel belts thereof and is longitudinally moveable with the upper surface thereof defining a third plane, the third plane forming a second angle with respect to the first plane where the second angle is equal to or less than the first angle. The outer end of the first finger is moveable between a retracted position below the upper surface of the transit conveyor (the first plane) and an extended position in which the movement of the finger causes the outer end to penetrate the first plane and move upward to a second position above the first plane. Accordingly, the outer end of the first finger advances through the intersection of the first plane as it moves between the first position and the second position.
The device further includes a motor for moving the first finger between the first and second position and a detector for detecting the position of one of the trailing edge of a first product with respect to the transit conveyor and a leading edge of a second product that reaches the transit conveyor. A synchronizing device is also provided that is connected to the motor and to the detector for initiating the advancement of the first finger from its first position toward the second position prior to the arrival of the leading edge of a second product at the intersection of the first and second planes. In the preferred embodiment, the outward end of the finger will reach the intersection between the first and third planes simultaneously with the leading edge of the second product and the first finger will be moving at the same speed as the second product.
In another aspect of the present invention, a second finger is provided having a length, an outer end, and an upper surface that falls within the second plane. The second finger is mounted on the leading end of the secondary delivery conveyor and is longitudinally moveable downwardly along the second plane parallel toward the path of movement of the first finger from a first position that is spaced above the first plane and a second position below the first position but above the first plane. A second motor is provided for moving the second finger between its first and second positions and the synchronizing device is connected to the second motor such that the second finger reaches its second position when the first finger reaches its second position and the second finger is in near proximity to the first finger while the first finger is in its second position. Accordingly, a second product arriving on the input conveyor is directed by the first finger into the third plane and guided to the second finger, thereby diverting the second product to the secondary delivery conveyor.
In one aspect of the invention, the second angle is equal to the first angle such that the second and third planes are congruent.
A better understanding of the invention will be had after a reading of the following detailed description taken in conjunction with the drawings, wherein:
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The transit conveyor 22 includes first and second rotating drums 24, 26 around which are fitted a plurality of spaced apart belts 28, 29, 30, 31, 32 with the upper surfaces of the belts 18-32 defining a plane 33. The upper surface of the input conveyor 14 and the upper surface of the primary delivery conveyor 18 may also fall within plane 33, but that is not necessary for the invention. For the purpose of this description however, the parts are depicted as being coplanar, such that undiverted products 12 moving along the plane 33 on the input conveyor 14 to the transit conveyor 22 and then to the primary delivery conveyor 18.
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Even for relatively planar products, such as sheets of shingles, the movement of the product 12 on the surface of a conveyor will cause agitation of the product as it moves and therefore a minimum spacing is required between the upper surface of the conveyor belt and any object that is positioned above the conveyor including the lower portions of the secondary delivery conveyor 20. Accordingly, the lower portions of the secondary delivery conveyor 20 must be a minimum height above the upper surface of the transit conveyor 22. A diverter 16 must guide a moving product 12 under that minimum height above the transit conveyor 22 as it moves from the surface of the transit conveyor 22 until it is taken up by the secondary delivery conveyor 20.
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It is important that the outer ends 56 of the first fingers 50-53 reach the intersection of planes 33 and 41 on conveyor 22 just as the leading end of the next product 12 reaches the intersection. It is also important that the longitudinal speed of the first fingers 50-53 be equal to the longitudinal speed of the product 12 as it reaches the intersection with plane 41 so that the outer ends of fingers 50-53 will direct movement of the product 12 upward toward the secondary conveyor 20. As can be seen, the leading edge of the product 12 is then directed upward immediately after the trailing edge of the preceding product 12 has passed through the intersection of planes 33 and 41 and little or no space is needed between successive products 12 as they move along conveyor 14.
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The diverter 16 can be operated to direct all product 12 to the primary conveyor 18 by retaining both sets of fingers 50-53 and 59-60 in their retracted positions, or can be operated to direct all product 12 to the secondary conveyor 20 by retaining both sets of fingers 50-53 and 59-63 in their extended positions.
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To cool the linear motors 57A, 57B, 68A, 68B and their associated linear bearings 75, a plenum 80 is provided below the motors 57A, 57B, 68A, 68B with pressurized clean air fed into the plenum 80 by a blower 82. The blower 82 draws air through a filter 85 so as to provide a clean environment within the enclosures. Alternately clean air may be drawn from outside the manufacturing environment through an input duct, not shown. Each of the motors 57A, 57B, 68A, 68B and its associated bearings 75 respectively, is enclosed in its own associated housing 157A, 157B, 168A, 168B respectively. Pressurized clean air from the plenum 80 enters one end, unnumbered, of each of the elongate housings 157A, 157B, 168A, 168B so that it passes over and cools the enclosed motor and bearing assembly and is vented out the far end through an opening 158A, 158B, 169A, 169B respectively, as shown in
The blower 82, the plenum 80 and the housings 157A, 157B, 168A, 168B form non-contact air seals around the enclosed motors so as to both cool and seal the bearings and the moving parts.
While the present invention has been described with respect to a single embodiment, it will be appreciated that many modifications and variations may be made without departing from the spirit and scope of the invention. It is therefore the intent of the appended claims to cover all such modifications and variations that fall within the scope of the invention.
Applicant Schreiber claims priority from his provisional application filed on Apr. 13, 2012 and assigned Ser. No. 61/623,983. The present application relates to assembly line diverters that divert every other product on a conveyer to a second conveyer wherein both the first and second conveyers feed packaging stations, and in particular to a short gap diverter that requires a minimum spacing between products to initiate a diversion.
Number | Date | Country | |
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61623983 | Apr 2012 | US |