Patent Publication Number: US-6712218-B2

Title: Soil screener

Description:
FIELD OF THE INVENTION 
     This invention relates to the field of devices for separating rocks, rubble, gravel and debris from soil and in particular to a selectively pivotable rigid mesh screen pivotally mounted on a supporting frame and adapted for use with skid-steer style front end loaders. 
     BACKGROUND OF THE INVENTION 
     It is well known that screened top soil has a certain resale value for use in landscaping and construction. During such construction it is often the case that during excavation or during land clearing or the like that quantities of top soil have to be moved and distributed in the construction site or otherwise removed from the construction site, there being a later need for screened top soil once construction is complete. It is now common that on such construction sites that relatively small skid-steer front end loaders such as sold under the trademark Bobcat are employed for minor excavation, distribution of top soil, and loading of top soil into containers for removal. Consequently, there exists a need for a robust portable soil screen device which is compatible with the use of skid-steer style front end loaders to efficiently and economically screen rocks, rubble, debris, and large particle size gravel from otherwise readily reusable top soil found for example existing on a construction site. 
     In the prior art, applicant is aware of U.S. Pat. No. 4,505,812 which issued to Lees for a Sieve Screen Deck on Mar. 19, 1985. What Lees discloses is a sieve screen deck having a plurality of wedge wires connected to an array of backing bars running longitudinally of the screen parallel to its fall line. The screen is connected to a frame so as to include a resilient means accommodating vibrating and flexing of the screen during rapping or vibration of the screen so as to screen solid particulate matter using slots having a width of from ten microns to four millimeters. The screen is not rotatably mounted to the supporting frame. Other patents also rely on vibrating a screen for example such as disclosed in U.S. Pat. No. 5,392,925 which issued to Seyffert on Feb. 28, 1995 for a Shale Shaker and Screen, and in U.S. Pat. No. 5,641,071 which issued Read et al. on Jun. 24, 1997 for a Convertible Material Separating Apparatus and Convertible Kits. Applicant is also aware of U.S. Pat. No. 6,059,119 which issued to Davis on May 9, 2000 for a Rock Screed Bucket. Vibratory mechanisms such as taught in these patents add complexity, weight and cost to the manufacturer of such screening devices. 
     Applicant is also aware of devices for screening which employ the use of inclined screens, for example, Canadian Patent No. 1,144,111 which issued Apr. 5, 1983 to Simbas for a Grading Plant, published International Patent Application No. PCT/US97/01722 filed Jan. 29, 1997 by Curtis for a Curved Freestanding Garden Sieve, U.S. Pat. No. 1,424,451 which issued to Crandall on Aug. 1, 1922 for a Combined Sand and Gravel Screen, and U.S. Pat. No. 1,510,742 which issued Oct. 7, 1924 to Gutleben for a Sand and Gravel Screen. Neither Simbas, Curtis, Crandall nor Gutleben disclose an inclined screen pivotally mounted along its upper edge to a support frame and adapted for complimentary ease of use with a skid-steer style front end loader bucket. 
     SUMMARY OF THE INVENTION 
     In summary the soil screening device of the present invention includes a screen frame having a screening surface, and a supporting frame. The supporting frame may have rearwardly disposed rigid uprights supporting the screen frame. The screen frame is pivotally mounted to a first upper member mounted at an upper end of the uprights, for pivoting between a lowered position and an elevated position. The supporting frame has a base frame extending forwardly of the uprights. Upper members of the base frame have at least one wedge selectively positionably mounted thereon, for example atop the upper member of the base frame. The wedge or wedges are positionable to engage a lower edge of the screen frame when in the lowered position bearing down on an upper inclined surface of the wedge or wedges. The wedge or wedges are selectively positionable relative to the upper members of the base frame so as to selectively adjust an angular orientation of the screen frame relative to the uprights. 
     The uprights define a first rear opening between the uprights and under the screen frame. The opening is sized to accept a front end loader bucket therethrough for engagement of the bucket with an underside of the screen frame. File base frame defines a second rear opening below the first rear opening. The second rear opening is sized to accept the bucket therethrough for engagement of the bucket with cross members of the base frame. The base frame may be substantially a parallelepiped and the first and second rear openings may be substantially rectangular. The uprights may be a parallel and spaced apart pair of uprights bounding opposite ends of the first and second rear openings. 
     The cross members may include at least a rear-most cross member adjacent the uprights. At least one rigid member may depend downwardly from the rear-most cross member for releasably locking behind a rear edge of the bucket when the bucket is fully inserted into and through the second rear opening. 
     The upper members may include at least one channel member forming an upwardly opening channel in which a wedge is slidably mounted. The at least one channel member may be perpendicular to the uprights, and may be orthogonal to the first rear opening. The at least one channel member may include locking means for releasably lockably positioning wedges along the at least one channel member. The at least one channel member may be a parallel pair of spaced apart channel members mounted adjacent opposite ends of the base frame, and consequently at least one wedge may be a pair of wedges mounted in the channel members. 
     The first upper member may be a horizontal cross bar between the uprights. An upper edge of the screen frame may be parallel to the horizontal cross bar and pivotally mounted thereto by hinge means. A deflecting bar may be mounted along the upper edge of the screen frame so as to at least partially cover the hinge means. 
     The base frame may be sheeted across the front thereof. An upper forward edge of the base frame may be bevelled and sheeted so as to extend beneath the lower edge of the screen frame when in the lowered position to deflect debris falling from the screening surface forwardly from the base frame. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is, in front perspective view, the soil screener according to the present invention. 
     FIG. 2 is, in rear perspective view, the soil screener of FIG. 1 with a skid-steer style front end loader illustrated in dotted outline approaching the rear of the soil screener. 
     FIG. 3 illustrates the soil screener of FIG. 2 mounted onto the bucket of the skid-steer style front end loader for transportation of the soil screener. 
     FIG. 3 a  is a partially cut away enlarged view of the mounting mechanism for mounting the soil screener of FIG. 3 onto the front end loader bucket. 
     FIG. 4 is, in side perspective view, the operation of the front end loader bucket rotating the soil screener screen upwardly. 
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
     As seen in FIGS. 1-4, the soil screener according to one embodiment of the present invention includes a rigid planar screen  10  mounted atop a rigid supporting frame  12 . Although not intending to be limiting, screen  10  may include two square frames, adjacently abutted so as to form a rectangle, each of the frames containing a square of expanded steel mesh  14  or the like rigidly mounted therein. The upper screen frame member  16   a  is pivotally mounted, by means of hinges  18  to an upper cross bar  20   a . Upper screen frame member  16   a  and lower screen frame member  16   b  are rigidly maintained in their parallel spaced apart relation by screen frame side members  16   c  and by screen frame intermediate members  16   d . Upper cross bar  20   a  is supported on rigid parallel uprights  20   b  mounted onto a rigid rectangular base  22 . An intermediate cross bar  20   c  extends between uprights  20   b  parallel to upper cross bar  20   a  and base  22 . Uprights  20   b  are mounted to base  22  at the rear corners of base  22 . A parallel pair of shorter front uprights  24   a  are mounted so as to extend vertically from the front corners of base  22 , parallel to rear uprights  20   b . Front uprights  24   a  extend upwardly as unitary members through a forty-five degree corner section  24   b  and extend contiguously into a horizontal supporting arm  24   c  rigidly mounted to rear uprights  20   b . Cross bar  26  is rigidly mounted to so as to extend between supporting cross arms  24   c.    
     A pair of channel members  28  are rigidly mounted atop supporting cross arms  24   c  so as to lie along the top surface of supporting cross arms  24   c  and so as to extend outwardly over corner sections  24   b . Channel members  28  are oriented so as to provide an upwardly open U-shaped channel in each of the parallel pair of planes containing supporting cross arms  24   c , corner sections  24   b  and front uprights  24   a . Rigid braces  30  are mounted to the free ends of channel members  28  and to front uprights  24   a  so as to support the free ends of channel members  28 . Rigid planar sheeting  32  may be mounted in the rectangular opening defined by the parallel pair of corner sections  24   b . The rectangular opening defined between the parallel pair of front uprights  24   a  may also be rigidly sheeted by sheeting  34 . 
     Wedges  36  are slidably mounted in channel members  28 . A pin  38  is insertable through pairs of apertures  28   a  in channel members  28  and through a corresponding bore (not shown) formed laterally through the base of wedges  36  so as to releasably lock the position of wedges  36  along the lengths of channel members  28 . Thus wedges  36  may be positioned in directions A so as to adjustably engage the underside of lower screen frame member  16   b . Wedges  36  thus allow the resting position of screen  10 , with lower screen frame member  16   b  resting on the upper surfaces of wedges  36 , to be rotatably adjusted in direction B about axis of rotation C. 
     In use, a skid-steer style front end loader such as the Bobcat™ illustrated, may easily lift screen  10  and supporting frame  12  by inserting the bucket through a lower rear opening in the frame and hooking the rear edge of the bucket opening, when the bucket opening is horizontal, behind down-turned rigid flanges  40  on cross bar  20   c  as seen in FIGS. 3 and 3 a . With flanges  40  hooked behind the rear upper edge of the bucket opening, a safety chain, which is rigidly mounted as by welding to cross bar  26  on supporting frame  12 , is wrapped over cross bar  20   c  so as to allow the hooking of a hook  44  mounted on the distal end of chain  42  onto a cross bar on the back of the bucket. With the bucket then bearing upwardly against cross bars  20   c  and  26 , raising the bucket simultaneously raises the supporting frame  12  so that it may be transported readily to a convenient work area on the site, for example, adjacent a supply of soil to be screened. 
     Once the supporting frame and screen has been positioned in a desired location, the bucket is lowered to place the supporting frame on the ground and so as to release the bucket from underneath flanges  40 . The bucket may then be retracted through the lower rear opening and screening operations may commence. The bucket may be immediately filled with unscreened soil and tipped from the bucket, once raised, in direction D down over deflecting flange  16   e  so as to cascade down onto and over mesh  14 . Soil and other fine particulates are then free to fall through the apertures of the mesh leaving the larger particles which will not pass through the apertures of the mesh to roll or slide downwardly off the screen in direction E. Rubble flowing or rolling off mesh  14  in direction E is deflected by sheeting  32  onto a waste pile accumulating in front of sheeting  34 . 
     An operator may adjust the inclination of screen  10  by inserting the bucket through an upper rear opening in the supporting frame and underneath the screen as seen in FIG.  4 . Raising or rotating the bucket pivots the screen about hinges  18 . This relieves the downward pressure of the screen frame bearing against wedges  36  so that the position of wedges  36  in channel members  28  may be adjusted to reduce or increase the inclination of screen  10  once lowered to again rest the screen frame against the wedges. Adjusting the inclination of screen  10  allows an operator to vary the amount of soil which may typically be screened from unscreened soil and rubble or gravel aggregate. 
     With the bucket underneath screen  10  so as to elevate the screen such as seen in FIG. 4, an operator may also slightly bounce the bucket up and down or slightly rotate the tip of the bucket up and down to assist in further filtering soil through the screen mesh or to assist in releasing any rubble or brush or the like which has not flowed or rolled off from the lower end of the screen. 
     As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.