Patent Application
20240189828
This invention relates generally to glass recycling machinery. In particular, the present invention is concerned with an apparatus for recycling laminated glass, such as automotive windshield glass and certain architectural glass. Laminated glass employed for these purposes comprises two (or more) sheets of glass laminated to either side of one or more plastic sheet(s). Recycling of such laminated glass items requires, in essence, that the glass be comminuted into small pieces while the plastic liner remains in larger pieces, enabling a size-based separation step, so that the glass and plastic can be separately recycled.
This application is directed to certain improvements in machinery for recycling laminated glass as described in U.S. Pat. No. 5,984,216 (“the '216 patent”). As such, much of the below description, and
One of the improvements made by the present application with respect to the '216 patent lies in the broadening of its scope to laminated architectural glass. Laminated architectural glass resembles automotive windshield glass in that it comprises two sheets of glass adhesively bonded to either side of a sheet of plastic, the idea in each case being that a broken glass item will not shatter when broken but will remain in one piece, for safety reasons. However, laminated architectural glass is typically thicker than automotive windshield glass, and requires somewhat different processing techniques—in general, more power is required to comminute the heavier architectural glass, which can be provided by slower operation.
Therefore, one improvement according to the present invention is to sense the presence of architectural glass as opposed to windshield glass, and to provide a circuit that slows the operation of the glass recycling machine when appropriate.
Other improvements made by the present invention with respect to the '216 patent, without limitation, are directed to the infeed mechanism, the breaker bar support assembly, and the disposition of the impactors around their drive shaft.
In the following, taken largely from the '216 patent, reference to automotive windshield glass is to be understood to include laminated architectural glass. Likewise, reference to an automotive windshield shop or the like should be understood to include a business that recycles architectural glass.
In order to efficiently recycle or dispose of an automotive windshield, it is desirable to comminute the glass. Numerous machines have been developed specifically for comminuting empty glass containers. These machines typically include an inlet opening through which the glass containers are inserted and an outlet opening through which the broken glass fragments and glass dust are ejected. To accomplish the breaking of the glass, these machines usually employ either a crushing apparatus or a hammermill form of breaker apparatus.
For several reasons, existing glass comminuting machines are not well adapted for the recycling or disposal of automotive windshields. First, such devices are extremely large and are typically only found at large recycling plants. It is not common for an auto glass shop to have ready access to such a recycling machine. Second, the inlet opening through which the glass enters the comminuting machine is typically of a dimension which requires that the windshield be broken into smaller pieces prior to its insertion into the opening.
Third, an automotive windshield is comprised of two layers of glass and a plastic liner bonded securely between them. This construction requires that the glass must first be freed from the plastic liner material before it can be recycled.
A fourth problem associated with existing devices employed for the recycling of automotive windshields is that machines that employ a crusher-type apparatus are susceptible to jamming when plastic is inserted into the machine's inlet. The presence of the plastic liner sandwiched between the two layers of glass thus prevents the use of this type of machine.
Finally, after the glass has been freed from the surface of the plastic liner, the two materials are commingled and must be separated for recovery and recycling.
It is therefore desirable to provide an apparatus that can accommodate a glass sheet of the dimensions of an automotive windshield, and thereby eliminate the need to fragment the sheet prior to beginning the recycling or disposal process.
It is also desirable to provide an apparatus that can strip the two layers of glass off of the inner plastic liner material and then separate the two substances for recovery.
It is a feature of the invention of the '216 patent to provide a compact automotive windshield recycling machine that can be used on site, thereby eliminating the need to transport the windshield to an independent recycling plant. Due to its small, compact size, the recycling machine of the '216 patent can be placed in a typical automotive or glass repair shop without taking up a large amount of valuable workspace. The compact, space-saving feature will also be of value to a central recycling plant.
It is a second feature of the invention of the '216 patent to provide a glass recycling machine having an inlet opening that will accommodate the full width of a typical automotive windshield, thereby eliminating the need to fragment the sheet of glass prior to utilizing the machine. The sheet of glass is drawn into the machine by dual feed rollers that each have a shaft on both ends. The shafts extend through openings in the housing side plates and turn in bearings each mounted on an offset. The lower offsets are fixedly mounted to the housing side plates while the upper offsets are slidably attached to the housing side plates, allowing the upper roller to be lifted upwardly to accommodate the thickness of the glass windshield.
It is another feature of the invention of the '216 patent to include a stationary breaker bar and an impactor assembly comprising an adjustable rotating impactor shaft driven for rotation and having a plurality of flexible impactors attached thereto. As the glass sheet is fed into the interior of the machine via the feed rollers, it passes over the stationary breaker bar and into the line of impact of the rotating flexible impactors. The combination of the stationary breaker bar and the rotating impactors acts to strip the glass from both sides of the inner plastic liner. The glass is comminuted into particles the size of fine gravel and sand while the plastic liner remains in much larger fragments.
It is a further feature of the invention of the '216 patent to provide a shaker screen below the rotating impactor shaft. The much smaller-sized glass particles pass through the shaker screen into a glass recovery container below the unit. The larger plastic fragments remain on the shaker screen and are carried out of the unit and into a separate recovery container. Alternatively, the glass and plastic may be separated from one another in a different machine performing size-based separation.
These and other advantages of the present invention will become more readily apparent upon reading the following detailed description and upon reference to the drawings in which
Referring now specifically to the drawings, there is illustrated an automotive windshield stripper/recycling machine, generally designated as 11, wherein like reference numerals refer to like elements throughout the drawings.
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According to the present invention, as described above, it was desired to broaden the scope of use of the device of the '216 patent to reach beyond automotive windshields and specifically to include laminated architectural glass. The latter is typically thicker than the former and is best processed at slower speeds. Therefore, it was desired to detect the thickness of the laminated glass member to be separated from the plastic central layer and slow the processing speed correspondingly.
More specifically, as heavier-gauge laminated glass is fed into the machine for separation of the glass from the plastic liner, the impactor shaft tends to slow due to the increased force required to break the glass. The typical AC motors used to power the impactor shaft are designed to run at constant RPM and therefore will draw more current in order to meet the increased load. This current increase is sensed and used to control the speed of the infeed rollers, so that the load on the impactor shaft and the current drawn are reduced to nominal levels.
It would also be within the scope of the invention to monitor the displacement of the upper infeed roller 14′ when a glass member is fed in for processing, and to control the infeed rollers' speed accordingly.
The '216 patent simply refers to the breaker bar 25 and does not go into detail. It was observed that over time in use the working upper corner of the breaker bar 25 became worn and rounded due to the many impacts of the impactors on the glass, and the consequent pounding of the glass against this corner of the breaker bar, reducing efficiency of operation. Therefore, over time in the commercialization of the invention of the '216 patent, the breaker bar was provided in the form of a breaker bar support beam 70 and a number of breaker bar edge members 72. See
According to an aspect of the present invention, the breaker bar support beam 70 with the breaker bar edge members 72 attached can be removed from the machine 11 through a side wall to facilitate this operation. See
Lower support bar 140, vibration-dampening rubber member 142, and second support bar 144 are external to the wall 15 of the machine 11, while breaker bar support beam 70 runs entirely through the body of the machine 11.
Thus, in order to provide a fresh cutting edge by removal and realignment or replacement of the breaker bar edge members 72, bolts 136 are removed, and hold-down bracket 130 with vibration-dampening member 134 are pivoted counterclockwise in the view of
Thus, according to the invention, the breaking of the two glass members and the stripping of the glass fragments from the plastic interior sheet takes place in two stages, both of which can happen immediately upon striking or over the course of multiple strikes, depending on several material and bonding factors. Initially, the glass must be fractured, just as if it was in a car accident, separating the glass itself into small pieces. The action of the impactors striking the laminated glass member against the rigid breaker bar accomplishes this. Next, the small pieces of glass must be separated from the plastic. The glass pane is now much more flexible due to the breakdown of mechanical integrity. As the impactors 26 spin and strike the sheet, the small, individual bits of glass that may be clinging to the plastic are violently squeezed against the breaker bar and are stripped by shearing mechanical forces.
The gap between the impactors 26 and the breaker bar edge members 72 is important as follows:
The impactors 26 should not be too close to the breaker bar edge members 72 or the impactors 26 will wastefully strike the breaker bar edge members 72.
The impactors 26 must be close enough to the breaker bar edge members 72 to create the approximate preferred size of glass particle, usually about ⅛″, though obviously a variety of sizes result, including a certain amount of dust.
Too large a gap will result in more unstripped volume, reducing output and efficiency.
A thicker laminated architectural glass member may require a somewhat larger gap, but once the impactors 26 strike, the thickness of the plastic needs to fit in the gap so that the remaining attached glass fragments can be stripped from the plastic liner. Processing of thicker glass members mainly requires more power and/or slower feed speeds, as described above.
As the impactors 26 wear down, the gap increases, requiring that the rotating shaft 27 be adjusted closer to the breaker bar for optimal performance.
As mentioned above,
Thus, as illustrated, an endless infeed belt 150 rides on rollers 152 and 154, where roller 152 corresponds approximately to roller 14′shown in other Figures. One of rollers 152 and 154 is driven by a motor (not shown). Rollers 152 and 154 are mounted on shafts journaled in bearings (not shown) mounted on opposed frame members 156 (only the distal member being shown) pivoting on a rod 158, such that the downstream roller 152 can be deflected upwardly against bias provided by springs (not shown) when a member of laminated glass to be comminuted is inserted therebetween. Belt tension is adjusted by way of threaded rods 168. Roller 152 with belt 150 thereover rests on top of bottom roller 14, which prevents belt 150 from coming into contact with infeed table 13.
The inner side of belt 150 may be formed to include a V-shaped wedge 160 fitting within correspondingly-shaped grooves 162 in rollers 152 and 154, to ensure the belt 150 stays in the correct position and does not slide off to one side or the other. Plural such wedges and grooves may be provided.
Protective baffles 164 and 166 may be provided to contain dust and glass fragments resulting from the comminution operation.
The embodiments disclosed herein have been discussed for the purpose of familiarizing the reader with the novel aspects of the invention. Although preferred embodiments of the invention have been shown, many changes, modifications and substitutions may be made by one of ordinary skill in the art without necessarily departing from the spirit and scope of the invention as described in the following claims.
