Patent Grant
6964341
The present invention is directed generally to a screen panel retainer system. More particularly, the present invention is directed to a screen panel retainer system for use in securing screen panels to a frame of a vibrating separatory device. Most specifically, the present invention is directed to a screen panel retainer system that utilizes elongated retainer bars, including self-expanding retainer pins and screen panel edge engaging ears, which are receivable in cooperatively shaped pockets in screen panel edge strips. The retainer pins on the elongated retainer bars are spaced to be receivable in the spaced holes or apertures which are typically situated on the upper surface of screen stringer rails provided in vibrating separatory machines. The retainer pins are expandable to securely hold the retainer bars in place and to thus retain the screen panels. The retainer bar ears releasably receive the screen panel edge strips. The screen panel retainer system of the present invention is equally suitable for use with separatory machines whose spaced screen stringer rail holes are of their proper dimension as well as those whose rail holes have become oversize due to wear.
Vibrating and other separatory screen assemblies are generally known in the art and are very useful in accomplishing the separation of materials on the basis of size of the materials to be separated. A slurry of liquid and entrained solids will be caused to run or flow across an upper surface of a screen panel assembly. Particles of a certain size and above will not pass through apertures in the screen panels and will thus be separated out. The screen panel assembly is caused to vibrate by an suitable means with this vibratory motion being beneficial in facilitating the proper separation of the material directed to the screen panel.
One such vibratory screen panel assembly is shown in U.S. Pat. Nos. 5,112,475 and 5,277,319, both the Henry, and both assigned to Conn-Weld Industries, the assignee of the present application. In these two patents, there is disclosed a panel mounting system for a vibrating screen assembly, and a panel which is securable in the vibrating screen assembly using the panel mounting system. A plurality of screen panels are secured to a panel deck of a frame portion of a vibrating screen assembly. A plurality of elongated hold downs or center retainers, which are made of a resilient elastomeric material, such as polyurethane, are provided with spaced anchoring pins along their bottom surface. These anchoring pins are receivable in apertures in an anchor member. Once the hold down members or center retainers have been secured to the anchor member, which is, in turn, attached to spaced cross members or tubes of the frame of the vibratory separator, the screen panels are placed atop the panel deck with their side edges in contact with the center retainers. Elongated key members are inserted into upwardly facing slots in the center retainers to spread wing portions of the retainers laterally outwardly. This spreading of the wings of the center retainers causes the wings to grip the side edges of the screen panels so that these panels are secured in the vibrating screen assembly.
The panel mounting system disclosed in the two above-referenced Henry patents, which are assigned to Conn-Weld Industries, utilizes screen panels and cooperating anchor members which are bolted, welded or otherwise secured to cross members of the panel deck of the vibrating screen assembly. An owner of a vibrating screen apparatus which is not provided with the appropriate anchor members disclosed in the prior Henry patents must make substantial revisions and modifications to his vibrating screen assembly if he is to be able to enjoy the advantages of the Conn-Weld Industries panel mounting system.
A center retainer assembly for a panel mounting system is disclosed in U.S. Pat. No. 5,398,817 to Connolly et al. and also assigned to Conn-Weld Industries. The center retainer assembly described in the '817 patent utilizes an elongated bolting bar which is encased in a resilient material and which includes an elongated center retainer. The center retainer assembly is placed into an upwardly facing retainer channel and is secured to the retainer channel by placement of the bolts carried by the bolting bar through holes in the retainer channel. The retainer channel is, in turn, secured to mounting plates that are attached to a cross tube or to a cross bar of a vibrating screen assembly.
Each of the screen panel retainer systems described in the above-mentioned patents has performed well and has been accepted by the industry. However, each still has required that the industry standard configuration of screen stringer rails placed atop cross tubes or cross bars of the frame portion of a vibrating separatory machine be modified in some way. Such modifications or re-fittings inevitably take time, require the services of technicians and meet with resistance on the part of equipment owners who want to purchase screen panels and panel retainers that will fit the machinery they already have, without the need for any modification, revision, re-working or equipment downtime.
Thus the need still exists for a screen panel retainer system that is compatible with current industry standard screening machines. In addition, the screen panel retainer system must have the capability to accommodate to both new machines, as well as to older, used machines. The screen stringer rails which are secured atop the cross tubes or cross bars of the typical vibrating separatory machine, are typically configured with spaced holes along their upper faces. These spaced holes are used for the attachment of the screen panels to the machine's frame.
When the machine is new, all of the holes on the screen stringer rails are of uniform size. A number of currently available screen panel retention systems depend on the proper dimensioning of those holes to accomplish the securement of the screen panels to the machine frame.
Vibrating separatory machines are frequently used in applications in which a relatively abrasive material is separated from a suspension fluid, such as water. The slurry of fine abrasive particles and the suspension fluid finds its way into all of the components of the screen assembly, including into the spaces that exist between the screen panel connection mechanisms and the holes or apertures in the screen stringer rails. Over the course of time, the slurry abrades the holes and causes them to enlarge. This abrading action is enhanced by the vibration to which the separtory machine is continually subjected.
Eventually, these holes in the screen stringer bars become enlarged. Since a number of the currently available panel retainer systems utilize some type of an interference fit of pins, pegs or the like into these holes, their enlargement is problematic. At some point, the stringer bar holes become so enlarged that they will no longer engage the pins or pegs with sufficient retentive force. At such time, the stringer bars have to be refurbished, the screen panel retainers have to be modified or the stringer bars simply have to replaced with new bars. In each instance, the process involves considerable work and the equipment being taken out of service.
A need thus exists for a screen panel retainer system which is suitable for use with stringer bars whose mounting holes are both properly sized and also ones that have become oversized due to wear. The screen panel retainer system of the present invention provides a device and an assembly which can accommodate a much greater variance in screen stringer rails than has been possible in prior systems. the screen panel retainer system of the present invention is a substantial improvement over the presently available systems.
It is an object of the present invention to provide a screen panel retainer system.
Another object of the present invention is to provide a screen panel retainer system useable to secure screen panels to a frame of a vibrating separatory machine.
A further object of the present invention is to provide a screen panel retainer system which include elongated panel retainer bars with self-expanding retainer pins.
Still another object of the present invention is to provide a screen panel retainer system which is configured for use with industry standard vibrating separatory machine configurations.
Yet a further object of the present invention is to provide a retainer system that will accommodate variations in hole sizes in screen stringer rails.
Even another object of the present invention is to provide a screen panel retainer system which requires no modification of existing vibrating separatory machines.
As will be discussed in detail in the description of the preferred embodiment, which is set forth subsequently, the screen panel retainer system in accordance with the present invention is usable in a vibrating separatory device to secure screen panels to existing screen stringer rails that are provided with spaced holes on their upper faces. The screen panels are retained in place by being provided with longitudinally extending screen edge strips that are configured with periodically spaced transverse pockets. These pockets are configured to releasably receive ears that extend up from elongated center and edge retainer bars. The retainer bars are molded from a resilient material, such as polyurethane and includes a central, also elongated metal spine. The spine has a plurality of longitudinally spaced apertures, with each such aperture being sized to receive a hex-headed expander bolt. The polyurethane retainer bar also is formed with a plurality of downwardly extending retainer plugs. Each such retainer plug underlies an aperture in the metal spine. Each retainer plug includes a threaded expander nut. The plugs are sized and configured to be insertable into the cooperatively spaced holes which are situated along the top face of the screen stringer rails. Once the plugs have been placed in the rail holes, suitable expander bolts are inserted through the apertures in the spine and are threaded into the expander nuts. As the expander nuts are drawn up toward the lower surface of the retainer bar underlying the spine, the polyurethane plugs, which each encase one of the expander nuts, expand radially. This radial expansion increases the diameter and circumference of each plug so that it will not pull out of the screen retainer rail hole into which it has been inserted.
Once the retainer bars are in place, the screen panels can be attached to them. This is done by snap-fitting the ears on the retainer bars into the cooperating shaped pockets on the screen edge strips. The retainer bar ears have tabs or hooks which fit into sockets in the screen edge strip pockets. These engagements are analogous to tongue and groove connections. The ears and the screen edges are sufficiently resilient so that there is sufficient deflection of the ear hooks and the socket edges of the pockets to allow this snap-fit of the ears in the pockets.
A plurality of dams are used to bridge the ends of each two longitudinally adjacent screen panels. These dams each include a metal reinforcement rod. The ends of each dam are provided with dam end pockets that are essentially the same, in shape as the screen edge strip side pockets. Once the screen panels have been installed, the transverse dams are then snap-fit into place. These dams act as screen panel end retainers. They key into the ends of the screen panel edge strips of each two longitudinally adjacent screen panels. They also extend transversely between laterally adjacent screen panels or between a screen panel and an adjacent machine side plate. The dams further act in their generally well-known manner to slow down the flow of the material being separated, or sized as it flows longitudinally over and through the profile wires that typically make up the screen panels.
The screen panel retainer system of the present invention is usable with various vibrating separatory machines while requiring no modification of the machines. The screen stringer rails on virtually all of the currently available machines have a standard hole configuration on their upper face. The downwardly extending plugs of the center and side retainer bars of the present invention are spaced and sized to fit into those stringer bar holes. There is no need for the use of additional adapters, plates, bolting mechanism or the like, as has been the case in prior devices. The plugs are so spaced and sized that they align with, and fit into the screen stringer rail holes. A vibrating separatory machine owner can thus adapt his machine to use the screen panels provided with the screen panel retainer assembly of the present invention with virtually no modification to his machine.
The plugs of the center and side screen edge retainer bars are molded of a resilient material, typically polyurethane. They each include an expander nut. The plugs themselves are configured to be snugly received in the screen stringer rail holes. Each plug has a small flair or lip adjacent its attachment to the undersurface of the retainer bar. In use, when the retainer bar is initially placed atop the stringer rail, and the plugs are pushed into the holes, the interference lip and the tip should be sufficient to prevent the retainer bars from falling off the stringer rails. After the expansion bolts have been threaded into the expansion nuts, and the nuts have been drawn up toward the retainer bar to expand the plugs radially, the retainer bar is firmly secured to its associated screen stringer rail.
As was mentioned previously, the size of the screen stringer rail holes tend to enlarge over the service life of the vibrating separatory machine. This hole enlargement has, in the past required the replacement of the screen stringer rails because the prior screen panel retention systems relied on an interference fit with only very limited possibly of expansion. In contrast, the plugs of the subject screen panel retainer system are expandable radially to an increased size that will vary with the travel distance of the expander nut toward the undersurface of the retainer bar. If the diameter of the screen retainer rail holes increases, due to abrasive action of the slurry being processed, the expansion bolts of the present screen panel retainer system can be rotated to pull the expander nuts closer to the retainer bar. The effect of this is the further radial expansion of the retainer bar plugs. Such further radial expansion will compensate for screen stringer rail hole size increases. The screen panel retainer system of the present invention is thus also easily adapted for use with new machines as well as with older machines, without requiring that the screen stringer rails of these older machines be replaced.
The screen panel retainer system in accordance with the present invention overcomes the limitations of the prior art. It is essentially universally usable with a wide variety of vibrating separatory machines. It is adaptable to a range of hole sizes caused by machinery use. The screen panel retainer system of the present invention is thus a substantial advance in the art.
While the novel features of the screen panel retainer system in accordance with the present invention are set forth with particularly in the appended claims, a full and complete understanding of the invention may be had by referring to the detailed description of the preferred embodiment which is presented subsequently, and as illustrated in the accompanying drawings, in which:
Referring initially to
A number of longitudinally extending screen stringer rails 40 are secured to top faces 42 of the transversely spaced cross tubes 34. These screen stringer rails 40 extend generally in the material flow direction A. In a typical vibrating separatory machine 30 each screen stringer rail 40 is a square stainless steel tube with an outer wall height and width of 2 inches and with a wall thickness of ¼ inch. It will be understood that the vibrating separatory machine 30 described above, and as will be further described subsequently, forms no part of the subject invention. It is the base to which the screen panels 28 are attached by operation of the screen panel retainer system 20 of the present invention.
As may be seen most clearly in
Referring again to
Retainer bar 22 is generally rectangular in cross-section and has a length sufficient to receive at least one edge of a screen panel 28, as will be discussed subsequently. The bar 22 has an upper surface 60, a lower surface 62, as seen more clearly in
Each retainer bar 22 is molded with a plurality of downwardly depending plugs, generally at 72, with each plug 72 underlying an associated spine bore 70. Each plug 72 has a generally cylindrical side wall 74 that is molded using the same resilient material, such as polyurethane which is used to mold the rest of the retainer bar 22 about the metal spine 50. Each plug 72 is attached to the lower face 62 of the retainer bar and has a free lower plug end 76. A central passage 78 extends down each plug, generally along a centerline of the cylindrical plug. The central passage 78 of each plug is aligned with the bore 70 in the spine 50, which is situated above, the plug 72, and with the chamfer 68 in the upper face 60 of the retainer bar 22.
A threaded expansion nut 80 is molded into each plug generally adjacent the plug lower end 76. The threaded expansion nut 80 is aligned with the central passage way 78 in each such plug 72. Each expansion nut 80 has a central threaded sleeve 82, a radially extending flange wall 84 and several circumferentially spaced barbs 86. The barbs 86 are cut into the flange wall 84 and are bent upwardly. They act as rotation prevention anchors so that the expansion nut 80 will not rotate in the plug 72 when it is engaged by a cooperating threaded expansion bolt, as will be discussed shortly.
Each plug 72 has, as was recited above, a generally cylindrical side wall 74. Adjacent its connection with the underside 62 of the retainer bar 22, each plug sidewall 74 is undercut, as indicated at 90. This undercut 90 has a height slightly less than the wall thickness of the screen stringer rail 40. The lower edge of the undercut 90 is defined by a small, radially outwardly extending lip or flange 92. That lip 92 is slightly greater in diameter than the cylindrical plug sidewall 74 and is preferably also slightly greater in diameter than is the diameter of the hole 44 on the upper face 46 of the screen stringer rail 40.
In use, when the retainer bars 22 are initially placed on the screen stringer rails 40, the plugs 72 will be received in the rail holes 44 so that the body of the plug, up to the lip or flange 92 will be within the hollow interior of the rail 40. This may be seen most clearly in
As the dimension of the rail hole 44 increases over time, which increase is, a result of the operation of the machine to separate abrasive slurries, it is possible to further draw up the expansion nut toward the bolt head 98 and toward the spine 50. Within limits, this capability of the retainer bar 22 of the screen panel retainer system of the present invention allows the use of one set of screen stringer rails 40 for a longer period of time than had previously been possible. Longer stringer rail life means less machine down time. So long as the plug diameter can be increased by further axial movement of the expansion nut 80 toward the metal spine 50, the retainer bar 22 can be held in place on the screen stringer rails 40.
Each retainer bar 22 is essentially the same length as a screen panel 28 which will be secured to the frame of the vibrating separatory machine 30, as may be seen in
Each retainer bar 22, as may be seen most clearly in
Referring now primarily to
Each screen panel 28 is bounded, on its two lateral sides 128 by a screen edge strip 24. Each such screen edge strip 24 is a one piece molded element which is also typically made of polyurethane. It may be somewhat more flexible and resilient than the retainer bar 22 with which it cooperates. Each screen edge strip 24 has an inner face 130, an outer face 132, a bottom surface 134 and a top surface 136. The inner face 130 of each screen edge strip 24 is molded with a plurality of spaced blind bores 138. These blind bores 138 are dimensional and spaced so that they will receive the tie rod ends 126 of the tie rods 124 of the screen panels 28. It may be desirable to make these blind bores 138 somewhat ovoid so that they will accommodate tie rod ends 126 that may be slightly bent or out of line. The blind bores 138 typically do not extend completely through the width of each screen edge strip 24.
Each end of the screen edge strip inner face 130 has a downwardly extending end flange or key 140. Several other similar intermediate flanges or keys 142 are spaced along the length of the inner face 130. These flanges or keys 140 and 142 are generally rectangular in side view and are somewhat wedge-shaped in end view, as may be seen in
Each screen edge strip key 140 or 142 is dimensioned to be securable in a cooperating shaped cut-out or keyway 150 on the retainer bar 22 to which the screen edge strip 24 will be attached. As may be seen in
The outer face 132 of each screen edge strip 24 is generally planar and is provided with a plurality of retainer ear receiving pockets 160. Each pocket 160, except for two end pockets 168, is generally T-shaped in plan view. Its depth is less than the width of each edge strip 24. Each edge strip 24 pocket has a depth that is approximately half of the width of a corresponding retainer bar ear 100. The pockets 160 each have a pair of grooves 164 that extend longitudinally from a central passage 166. The pocket grooves 164 are dimensioned to receive the ear hooks 106. This assembled configuration can be seen in
Again referring to
As depicted in the exploded view of
Attachment of the screen panel assemblies 120 to the side panels 32 of the vibrating separatory machine 30 is accomplished by using the side panel structure typically found in vibrating separatory machines. A side board, generally at 200, as seen in
During installation of the screen panel assemblies 120 on the vibrating separatory machine 30, the panel assemblies 120 are laid onto the screen stringer rails 40 with the screen edge strips 24 aligned with the retainer bars 22 that have previously be attached to the tops 46 of the screen stringer rails 40, as was discussed above. The side boards 200 are initially not in place. Once all of the screen panels have been put down onto the retainer bars 22 and the ears 100 and half ears 110 have been pushed into the pockets and half pockets 160 and 170, the side boards 200 are then put in place. Each side board has a key slot 210 at each of its ends. The key slots 210 are the same width as the inner keyways 178 on the screen edge strip ends. Once all of the screen panels have been put in place, the side boards 200 are moved laterally into contact with the side plates 32. This lateral movement is guided by the cooperative shapes of the side board bottom surface 206 and the complementary upper face of the screen edge strips 24. The various dams 24 are then installed, as was discussed above. The side board end key slots 210 of abutting side boards 200 receive the outer end of the outward dams, as depicted in
Removal of a screen panel assembly 120 or of a plurality of screen panel assemblies 120 is accomplished by reversal of the installation procedure. The wedge blocks 212 can be hammered out and the outer dams 24 can be pried up using a tool such as a pry bar or a screwdriver. The side boards 200 can be moved laterally. Now any desired screen panel assembly 120 can be removed by removal of the overlying dams 24 and by separation of the screen edge strips 24 from their associated retainer bars 22. It is preferable to start such a separation at a screen panel end. Once a screen panel end has been raised, the entire panel assembly 120 can be pulled up. The resilient ears and half ears on the retainer bar are pulled out of their pockets and half pockets, leaving the retainer bars 22 in place. If it is determined that the retainer bars 22 are no longer as securely attached to the screen stringer rails 40 as they were on initial installation, typically due to stringer rail holes 44 becoming enlarged, the expansion bolts 96 can be tightened. This will further draw the expansion nuts 80 up toward the undersurface of the retainer bars and will increase the radial dimension of the plugs, as depicted in
The screen panel retainer system of the present invention overcomes the limitations of prior systems. It is adaptable for use with various separatory machines and does not require any machine modifications. The retainer bars are configured to fit the industry standard screen stringer rail hole pattern. No additional plugs, pins, inserts or other ancillary securement devices are required. Screen panel assemblies snap fit onto the retainer bars using only foot pressure. Once in place, with the dams installed, the system is tied or keyed together so that it is very unlikely that a panel will become dislodged. However, panel removal, if necessary, is quickly accomplished. The screen panel retainer system of the present invention thus is clearly a substantial advance in the art.
While a preferred embodiment of a screen panel retainer system in accordance with the present invention has been set forth fully and completely hereinabove, it will be apparent to one of skill in the art that changes in, for example, the particular resilient material used, the type of profile wire used on the screen panels, the number of panels secured to a machine frame and the like could be made without departing from the true spirit and scope of the present invention, which is to be limited only by the appended claims.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3795311 | Martin | Mar 1974 | A |
| 4046347 | Bryan | Sep 1977 | A |
| 4909929 | Tabor | Mar 1990 | A |
| 5112475 | Henry, Jr. | May 1992 | A |
| 5277319 | Henry, Jr. | Jan 1994 | A |
| 5361911 | Waites et al. | Nov 1994 | A |
| 5398817 | Connolly et al. | Mar 1995 | A |
| 6206200 | Gilles et al. | Mar 2001 | B1 |
| Number | Date | Country | |
|---|---|---|---|
| 20050167341 A1 | Aug 2005 | US |
