Patent Publication Number: US-11391026-B2

Title: Tamper-proof strainer and drain stop assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of priority of U.S. provisional application No. 62/989,454, filed Mar. 13, 2020, the contents of which are herein incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to strainers and, more particularly, to a tamper-proof strainer and drain stop device. 
     A strainer stops large particles from clogging a commercial drain. However, currently available strainers may be easily removed, causing unacceptable materials to pass through. Moreover, none of the currently available strainers can stop liquids from passing through, causing the operator to have to find alternate means to stop the drain so the sink may fill with water. 
     As can be seen, there is a need for a strainer that is not easily removed and can stop passage of liquids therethrough. 
     SUMMARY OF THE INVENTION 
     The inventive strainer performs all three major functions—strain, stop, and lock. The stopper may be locked into the drain using tamper proof hardware to prevent unauthorized removal. 
     In one aspect of the present invention, a combination strainer and drain stop assembly is provided, comprising: a strainer body comprising a strainer disk having a substantially planar surface with a first central aperture and slotted openings sized to remove predetermined particle sizes from a liquid; a rotatable stopper disk having a second central aperture and lugs extending through the slotted openings; a lock assembly comprising a lock block having a third central aperture perpendicular to an axis thereof, a locking wedge with lateral ramp faces, and a threaded insert housed within the locking wedge, wherein the lock block is configured to accommodate the locking wedge; and a screw extending through the assembly from the first central aperture through the second central aperture and the third central aperture to the threaded insert, said screw operative to raise the locking wedge into the lock block when pivoted. 
     In another aspect of the present invention, a tamper-resistant flow control device is provided, comprising: a lock assembly comprising a rectangular lock block slidably housing a lock pin at each end and a truncated wedge therebetween, said truncated wedge having a ramp face corresponding to each lock pin and a centrally located cylindrical threaded insert; and a slotted strainer housing having arcuate slots through which a plurality of protrusions extends from a rotatable flow control disk, said slotted strainer housing having a pair of diametrically opposed apertures; wherein the lock assembly is fastened within the slotted strainer housing with a fastener operative to raise the truncated wedge into the rectangular lock block, urging the lock pins to extend through the diametrically opposed apertures such that the tamper-resistant flow control device is secured within a drain; and wherein the plurality of protrusions is effective to rotate the rotatable flow control disk between an open position operative to enable fluid flow and a closed position operative to restrict fluid flow. 
     These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description, and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the invention; 
         FIG. 2  is a perspective view of the invention with the stopper rotated; 
         FIG. 3  is an exploded view thereof; 
         FIG. 4  is a sectional view thereof, taken along line  4 - 4  in  FIG. 1 ; and 
         FIG. 5  is a sectional view thereof, showing the tamper proof lock undone. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims. 
     Broadly, one embodiment of the present invention is a combination strainer and drain stop that may be locked into a drain. 
     The strainer has small openings that allow liquids and small solids to pass and prevent large objects from passing though. The strainer may be made with openings sized to prevent predetermined particle sizes from passing through. 
     Under the openings, there is a plate that may rotate to close the openings so the strainer may hold back liquids. The stopper plate behind it is rotatable to allow the openings to either remain open or closed. Once closed, no items may pass and fluid flow is restricted through the strainer. The adjustable rotating strainer plate may only be placed on the inside of the strainer body. 
     The lock assembly uses a truncated wedge that is raised and pulled in using a tamper proof screw. The wedge pushes two plungers outward to lock or secure the strainer into the sink drain. The lock assembly may use any type of fastener or screw. By use of a tamper proof or tamper-resistant screw and expanding plungers, the strainer is difficult to remove without tools or damaging it. 
     The strainer may be modified in size to work in any type of drain or process where liquid flow and the passing of solids needs to be controlled. 
     A method of making the strainer includes the following. The strainer may be assembled by placing the adjustable rotating strainer plate into the back of the strainer main body. The lock assembly is then placed in the back and the bosses lock into the holes in the strainer body which holds it all together. A tamper proof screw is threaded down from the top. 
     The materials and methods of making the strainer components are not particularly limited. For example, the materials may be molded from plastic. 
     A method of using the inventive strainer follows. The strainer may be placed into a sink drain and the center bolt may be tightened to prevent unauthorized removal. The stopper plate may be placed in the open position or closed position depending on whether the sink needs to drain or fill. In an open position, radially extending apertures in the stopper plate align with apertures in the strainer and are operative to enable liquid flow. 
     Referring to  FIGS. 1 through 5 ,  FIG. 1  shows a strainer assembly  10  or tamper-resistant flow control device according to an embodiment of the present invention, comprising a strainer body  12  or housing having a cylindrical sidewall and a substantially planar strainer disk with a slotted surface, a first central aperture, and a strainer body lip  30  extending beyond the cylindrical sidewall. 
       FIGS. 3 and 4  illustrate the internal components of the strainer assembly  10 . A rotatable strainer stop  14  disk or flow control disk attached underneath the slotted surface has apertures corresponding to the slots in the strainer body, a second central aperture, and stop moving lugs  16  or protrusions that extend therefrom through arcuate slots in the strainer body  12  slotted surface and are effective to move the stop  14  disk between an open and a closed position. A rectangular lock block  18  beneath the strainer stop  14 , with a third central aperture, slidably houses a pair of lock pins  24  retractably extending axially from each end of the lock block  18  body and has a central aperture perpendicular to the axis. The cylindrical sidewall of the strainer body  12  has diametrically opposed apertures through which the lock pins  24  may slidably move. A locking wedge  20  with lateral ramp faces  22  vertically houses a centrally located threaded insert  28 . The lock block  18  is configured to accommodate the locking wedge  20 . A tamper proof screw  26  extends axially through the center of the strainer assembly  10 , the strainer stop  14  and vertically through the lock block  18 . 
     As shown in  FIG. 2 , the slots in the strainer body  12  may be closed by sliding the stop moving lugs  16  so that the apertures align with non-slotted portions of the strainer body  12  surface, leaving the strainer body  12  slots blocked by non-apertured portions of the rotatable strainer stop  14 . 
     As shown in  FIG. 5 , the strainer assembly  10  may be placed in a drain  32  with the strainer body lip  30  resting on the edge of the drain  32 . As the tamper proof screw  26  pivots within the threaded insert  28 , the locking wedge rises into the lock block  18 , and the lock pins  24  are urged through the sidewall apertures by the ramp faces  22 , locking the strainer assembly  10  so that it is fastened into place. 
     It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.