METHOD AND APPARATUS FOR COOLING THE IMPULSE MECHANISM OF A VIBRATORY DEVICE

Abstract

An impulse mechanism for a vibratory device includes an eccentrically weighted shaft that is adapted to be rotated to create vibratory forces. A fan component is mounted on the eccentrically weighted shaft. The fan component has a plurality of fan blades spaced around its periphery.

Claims

1. An impulse mechanism for a vibratory device comprising: (a) an eccentrically weighted shaft that is adapted to be rotated to create vibratory forces; (b) a fan component that is mounted on the eccentrically weighted shaft, said fan component having a plurality of fan blades spaced around its periphery.

2. The impulse mechanism of claim 1 wherein each of the plurality of fan blades are curved.

3. The impulse mechanism of claim 1: (a) wherein the eccentrically weighted shaft comprises an eccentrically weighted drive shaft; (b) wherein the fan component is combined with a drive sheave component to form a unitary structure comprising a combination drive sheave and fan; (c) which includes a drive belt that is operatively attached to the sheave component of the combination drive sheave and fan.

4. The impulse mechanism of claim 3 wherein: (a) the combination drive sheave and fan has an outer side and an inner side; (b) the fan component of the combination drive sheave and fan is on the inner side of the combination drive sheave and fan; (c) the sheave component of the combination drive sheave and fan is on the outer side of the combination drive sheave and fan.

5. The impulse mechanism of claim 4 wherein the combination drive sheave and fan includes openings on its outer side through which air is drawn by rotation of the combination drive sheave and fan.

6. The impulse mechanism of claim 5 wherein the combination drive sheave and fan comprises a centrifugal fan component that: (a) draws air through the openings on the outer side of the combination drive sheave and fan; (b) accelerates the air as the fan blades redirect the air flow by 90; (c) disperses the air flow radially from the center of the combination drive sheave and fan.

7. The impulse mechanism of claim 3: (a) wherein the eccentrically weighted drive shaft is supported by bearings; (b) which includes a wheel case that encloses the bearings supporting the eccentrically weighted drive shaft, said wheel case having a wheel case cover; (c) wherein the fan component of the combination drive sheave and fan is adapted to direct air across the outer surface of the wheel case cover as the eccentrically weighted drive shaft is rotated.

8. The impulse mechanism of claim 7 wherein the wheel case contains a lubricant.

9. The impulse mechanism of claim 7 which includes a guard that is mounted to the outside of the wheel case and adapted to enclose the combination drive sheave and fan.

10. The impulse mechanism of claim 9 wherein the guard: (a) includes a guard side cover having an opening that allows air to be drawn into the combination drive sheave and fan as the drive shaft is rotated; (b) is adapted to protect the combination drive sheave and fan from impact by materials being processed by the vibratory device.

11. The impulse mechanism of claim 9 wherein the guard is adapted to channel and accelerate the air moved by the fan blades of the combination drive sheave and fan to improve the convection heat transfer from the surface of the side cover for the wheel case.

12. The impulse mechanism of claim 11 wherein the guard comprises: (a) an enclosure that is adapted to protect the combination drive sheave and fan from impact by materials being processed by the vibratory device; (b) a guard side cover for the enclosure that is generally parallel to the side cover for the wheel case, said guard side cover having an opening that allows outside air to be drawn into the guard by the rotation of the combination drive sheave and fan; (c) an opening in the end of the enclosure away from the combination drive sheave and fan; (d) a top wall for the enclosure which is provided with a plurality of air outlets; so that air is drawn into the guard by rotation of the combination drive sheave and fan and directed to flow across the outer surface of the side cover for the wheel case, with a portion of this air flowing out the opening at the end of the enclosure and a portion flowing out the air outlets in the top wall of the enclosure.

13. The impulse mechanism of claim 11 wherein the guard is adapted to direct air moved by the fan blades of the combination drive sheave and fan across the lower portion of the side cover for the wheel case.

14. The impulse mechanism of claim 11 wherein the guard is adapted to direct air moved by the fan blades of the combination drive sheave and fan across the lower portion of the side cover for the wheel case and then upwardly across the side cover.

15. The impulse mechanism of claim 14 wherein: (a) the combination drive sheave and fan has a motor side; (b) the guard comprises: (i) an enclosure that is adapted to protect the combination drive sheave and fan from impact by materials being processed by the vibratory device; (ii) a guard side cover for the enclosure that is generally parallel to the side cover for the wheel case, said guard side cover having an opening that allows outside air to be drawn into the guard by the rotation of the combination drive sheave and fan; (iii) a closed end of the enclosure away from the combination drive sheave and fan; (iv) a top wall for the enclosure which is provided with a plurality of air outlets; (v) curved ducting that wraps around the motor side of the combination drive sheave and fan and slopes downwardly from the top of combination drive sheave and fan towards the closed end of the enclosure, which curved ducting has a plurality of upper air outlets near the end of the guard away from combination drive sheave and fan; so that air is drawn into the guard by rotation of the combination drive sheave and fan and directed to flow across the outer surface of the lower portion of the side cover of the wheel case and then upwardly across the side cover through the upper outlets in the curved ducting and through the air outlets in the top wall of the enclosure after passing across the upper portion of the side cover for the wheel case.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The presently preferred embodiments of the invention are illustrated in the accompanying drawings, in which like reference numerals represent like parts throughout, and wherein:

[0028] FIG. 1 is a side perspective view of a vibratory screen assembly which has been modified to include a preferred embodiment of the invention.

[0029] FIG. 2 is a side perspective view of the components of the impulse mechanism of the vibratory screen assembly shown in FIG. 1, with the side cover of the wheel case and the guard removed.

[0030] FIG. 3 is a sectional end view of a portion of the wheel case of the impulse mechanism including the drive shaft and the combination drive sheave and fan that is a part of a preferred embodiment of the invention.

[0031] FIG. 4 is a side perspective view of a preferred embodiment of the combination drive sheave and fan that is a part of the invention.

[0032] FIG. 5 is a side perspective view of a preferred embodiment of the combination drive sheave and fan that is a part of the invention, showing an air flow pattern that may be generated across the wheel case by the combination drive sheave and fan.

[0033] FIG. 6 is a side perspective view of a preferred embodiment of the combination drive sheave and fan that is a part of the invention, showing an air flow pattern that may be generated by the combination drive sheave and fan, using a first embodiment of air ducting in a guard.

[0034] FIG. 7 is a side perspective view of a preferred embodiment of the combination drive sheave and fan that is a part of the invention, showing a second embodiment of air ducting in a guard.

[0035] FIG. 8 is a side perspective view of a preferred embodiment of the combination drive sheave and fan that is a part of the invention, showing an air flow pattern that may be generated by the combination drive sheave and fan, using the air ducting in the guard that is shown in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

[0036] This description of preferred embodiments of the invention is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. The drawing figures are not necessarily to scale, and certain features of the invention may be shown exaggerated in scale or in somewhat schematic form in the interest of clarity and conciseness.

[0037] Vibratory screen assembly 10 is shown in FIG. 1. Vibratory screen assembly 10 is comprised of side plates 12 and 14 and three screen decks 16, 18 and 20 that are connected to the side plates by fasteners, by welding or by other means known to those having ordinary skill in the art to which the invention relates. Each screen deck includes sizing media that is adapted to allow material of a particular particle size to pass through. Of course the invention may also be applied to vibratory screen assemblies having one, two, or more than three screen decks, as well as to a vibratory feeder having a feeder pan instead of a screen deck. The combination of side plates 12 and 14 and screen decks 16, 18 and 20 is commonly referred to as a screen basket or body. A combination of side plates and a pan floor on a vibratory feeder (not shown) is referred to as a pan assembly.

[0038] An impulse mechanism 22 is mounted to vibratory screen assembly 10, and is adapted to generate vibratory forces to vibrate the screen basket (or the pan assembly of a vibratory feeder) during operation. The screen basket (or the pan assembly of a vibratory feeder) is supported and isolated from base structure 24 by springs 26. These springs vertically support the screen basket (or pan assembly) in compression or tension. The springs can also be adapted or configured and arranged to support the screen from horizontal movement, if desired. Typical spring designs include coiled steel, rubber core with reinforcing cords, leaf springs, tension springs and rubber torsion springs that compress the rubber mechanically when subject to torsion.

[0039] Impulse mechanism 22 comprises drive shaft 27, and shafts 28 and 29, all of which have weight assemblies 30 that are eccentrically mounted thereon. In other embodiments of the invention (not shown), eccentric weight assemblies may be integrally formed with the shafts of the impulse mechanism. Each of shafts 27, 28 and 29 is supported by bearings 32 (shown in FIG. 3) that are coupled to each of side plates 12 and 14 within a wheel case mounted on the outside of each of the side plates, including wheel case 33 that is mounted on the outside of side plate 12 (shown in FIGS. 2 and 3). Wheel case 33 comprises an enclosure that includes side cover 34 (shown in FIG. 3, but removed for clarity from FIG. 2).

[0040] In the preferred embodiment of the invention, eccentrically mounted weight assemblies 30 are located on each side of the screen basket, i.e., in wheel case 33 on the outside of side plate 12 (shown in FIG. 2) and in a wheel case (not shown) on the outside of side plate 14. When weight assemblies of equal mass are located in this manner and in the configuration illustrated in FIG. 2, the impulse mechanism provides equal weight on each side of the impulse mechanism and equal radial position timing for the shafts of the impulse mechanism. During operation of impulse mechanism 22, shafts 27, 28 and 29 rotate and transfer rotational motion to the eccentrically mounted weights. Thus, as shown in FIG. 2, combination drive sheave and fan 35 is mounted on drive shaft 27, and the drive sheave component 36 of combination drive sheave and fan 35 is operatively attached to motor 38 by drive belt 40. Spring tensioned idler sheave 41 maintains proper tension in drive belt 40 while the screen basket is vibrating, and it accommodates the movements of the screen basket. Power transmission gears 42, 44 and 46 are used to transfer rotational motion to shafts 28 and 29 and to set the timing and direction of rotational motion to achieve the desired vibrational pattern of amplitude or stroke, and direction or angle of the major stroke axis of the screen basket. Thus, power transmission gear 42 is mounted on drive shaft 27, which meshes with power transmission gear 44 on shaft 28 so that rotation of drive shaft 27 in one direction by motor 38 will cause shaft 28 to rotate in the opposite direction. Power transmission gear 46 on shaft 29 is also adapted to mesh with power transmission gear 44 on shaft 28 so that shaft 29 will rotate in the opposite direction to that of shaft 28 and in the same direction as drive shaft 27. Operation of impulse mechanism 22 in this manner causes the rotating eccentrically mounted weights to generate centrifugal forces that vibrate the screen basket.

[0041] One or more shaft tubes 48 (shown in FIG. 3) can be used to add support between side plates 12 and 14. These shaft tubes are mounted to the inner surface of each of the screen side plates and are typically concentric with the shafts of the impulse assembly, such as eccentrically weighted drive shaft 27, as shown in FIG. 3. The shaft bearings and gears within the wheel case, such as bearing 32 and gear 42 within wheel case 33, are typically lubricated with a lubricant such as gear oil that is contained within reservoir 50 that is defined by the wheel case. During operation of the vibratory device, bearings 32 and gears 42, 44 and 46 generate heat from friction. This heat is transferred into the lubrication oil within the reservoir in the wheel case, to the structural components of the wheel case, to the mechanical components of the impulse mechanism, and to screen side plates 12 and 14. Some of the heat generated is dissipated by the wheel case due to natural convention heat transfer from the large surface area of wheel case, including side cover 34.

[0042] According to a preferred embodiment of the invention, fan component 52 is combined with drive sheave component 36 to form a unitary structure comprising combination drive sheave and fan 35 (best shown in FIG. 4). Fan component 52 has a plurality of fan blades 54 spaced around its periphery which are adapted to accelerate and direct air movement across the outer surface (including side cover 34) of wheel case 33 as drive shaft 27 is rotated. Preferably, fan blades 54 of combination drive sheave and fan 35 are curved as shown in FIG. 4 to increase efficiency. The construction of fan blades 54, and their location on the inner side of combination drive sheave and fan 35 helps to insure that fan component 52 is also adapted to withstand impact from sand, pebbles and rocks that could enter into or otherwise contact combination drive sheave and fan 35.

[0043] As shown in FIG. 5, combination drive sheave and fan 35 comprises a unitary structure including centrifugal fan component 52 that draws air through the openings 56 on the outer side of the combination drive sheave and fan, accelerates the air as the fan blades redirect the air flow by 90, and disperses the air flow radially from the center of combination drive sheave and fan 35 across side cover 34 of wheel case 33.

[0044] In preferred embodiments of the invention, impulse mechanism 22 includes a guard having a guard side cover and comprising an enclosure that is mounted to the outside of wheel case 33 and adapted to generally enclose the combination drive sheave and fan 35 in order to protect it against impact from sand, pebbles, rocks and other materials that may be put into motion by the operation of the vibratory device.

[0045] A first embodiment of the guard is shown in FIG. 6. This embodiment comprises guard 58, comprising an enclosure having a guard side cover (not shown) that is generally parallel to side cover 34 of wheel case 33. This guard side cover (like guard side cover 158 shown in FIG. 1) includes an opening that allows outside air to be drawn into guard 58 by the rotation of combination drive sheave and fan 35. As shown in FIG. 6, guard 58 is open at end 59, providing an air outlet away from combination drive sheave and fan 35. Guard 58 also has a top wall 60 which is provided with a plurality of air outlets 62. This configuration of guard ducting and air outlets allows cooling air drawn into the guard by combination drive sheave and fan 35 to flow across the outer surface of side cover 34 of wheel case 33. A portion of this air flows out open end 59 of guard 58, and a portion flows out air outlets 62. The guard is mounted so as to be easily removed in order to change drive belt 40 and allow for inspection or adjustment of eccentrically mounted weights 30.

[0046] A second embodiment of the guard is shown in FIGS. 1, 7 and 8. As shown therein, guard 157 comprises an enclosure that is provided with guard side cover 158. Guard side cover 158 has a circular opening 159 that is aligned with combination drive sheave and fan 35 so as to allow outside air to be drawn into guard 157 by the rotation of combination drive sheave and fan 35. Unlike guard 58, guard 157 has a closed end 160; however, its top wall 161 is provided with a plurality of air outlets 162. Guard 157 also includes curved ducting 163 that wraps around the motor side of combination drive sheave and fan 35 and slopes downwardly from the top of combination drive sheave and fan 35 towards closed end 160. Ducting 163 has a plurality of upper air outlets 164 near the end of guard 157 away from combination drive sheave and fan 35. This configuration of guard ducting and air outlets allows cooling air drawn into the guard by combination drive sheave and fan 35 to flow across the outer surface of the lower portion of side cover 34 of wheel case 33 and then upwardly across the side cover through upper outlets 164 and through outlets 162 in the top wall of the guard after passing across the upper portion of the side cover for the wheel case. Because of the configuration of guard 157, it will accelerate air drawn through opening 159 across the side cover for the wheel case to a greater speed than does guard 58 to improve the convection heat transfer from the surface of the wheel case. The guard is mounted so as to be easily removed in order to change drive belt 40 and allow for inspection or adjustment of eccentrically mounted weights 30.

[0047] Although this description contains many specifics, these should not be construed as limiting the scope of the invention but as merely providing illustrations of the presently preferred embodiments thereof, as well as the best mode contemplated by the inventors of carrying out the invention. The invention, as described and claimed herein, is susceptible to various modifications and adaptations, as would be understood by those having ordinary skill in the art to which the invention relates.