Abstract:
In previous netting systems using disposable netting frames, the wooden frame may become jammed in the diverter frame. The present invention provides a rigid frame for installing and holding the wooden netting frame in the diverter frame and which releases the wooden frame for disposal.

Description:
TECHNICAL FIELD 
   The invention relates to wastewater treatment and more particularly to a method and apparatus for installing and removing disposable netting frames from Combined Sewer Overflow netting systems. 
   BACKGROUND 
   Combined Sewer Overflow (“CSO”) netting systems are commonly used to provide “floatables” control for in-line, end-of pipe, and floating applications as well as on storm drain outfalls, clarifiers and various industrial applications. In some cases the netting sacks are clamped onto a metal nose box which is attached to a metal lifting assembly removably held in the main diverter frame. When the netting sack is full, the entire assembly is lifted out of the diverter frame, the netting sack is unclamped from the nose box and discarded, and a new netting sack is reinstalled on the nose box and the entire assembly is then replaced in the diverter frame. This process is time consuming, so a method of using netting sacks on disposable wooden lifting frames has been developed. In this case, the mouth of the netting sack is fixed to a rectangular disposable wooden frame which slides into guide rails in the diverter frame. When the netting sack is full, a truck crane is used to lift the wooden frame and attached netting sack out of the guide rails by looping a strap around the bag and frame and attaching it to the lifting cable. The entire assembly is then removed and discarded. The problem with this system however is that the wooden frame often expands or warps in the guide rails and jams or breaks when attempts are made to remove it from the guide rails, so workers must descend into the diverter frame and use tools to remove it. There is therefore a need for a quick and convenient means for removing and replacing disposable netting sacks. 
   SUMMARY OF INVENTION 
   The present invention provides a rigid frame for installing and holding the wooden netting frame in the diverter frame and which releases the wooden frame for disposal. The invention provides an apparatus for installing and removing disposable netting frames, comprising two opposed rigid parallel frame members, the frame members being adapted to removably receive between them a netting frame, each frame member being sized to be received in the receiving frame and having means for removably attaching lifting means. According to one aspect, the invention provides an apparatus for installing and removing disposable netting frames, comprising two opposed right-angled frame members, the frame members being adapted to receive a netting frame, each having a vertical frame member and a horizontal frame member, the horizontal frame members each having a first end adjacent to and opposed to the first end of the other horizontal frame member, and a second end, the opposed ends of the horizontal frame members being pivotally connected and having first means for selectively attaching lifting means, each horizontal frame member having second means for pivotally attaching lifting means spaced from the first end towards the second end of the horizontal frame member, third means for selectively attaching lifting means, wherein the third means for pivotally attaching lifting means is pivotally connected to the first means for selectively attaching lifting means, and means for selectively and releasably connecting the third means for selectively attaching lifting means to the first means for selectively attaching lifting means. 
   The invention further provides a method of installing and removing disposable netting frames comprising: a) providing frame members which comprise two opposed rigid parallel frame members, the frame members being adapted to removably receive between them a netting frame, each frame member being sized to be received in the receiving frame and having means for removably attaching lifting means; b) placing a netting frame in the frame members; c) placing the frame members and netting frame in a receiving frame; d) removing the frame members and netting frame from the receiving frame; and e) releasing the netting frame from the frame members. 

   
     DESCRIPTION OF DRAWINGS 
     In drawings which disclose a preferred embodiment of the invention: 
       FIG. 1  is an elevation view of a netting sack and frame in place and being removed from a lifting basket; 
       FIG. 2  is a perspective view of the invention holding a disposable wood frame in raising and lowering configuration, with netting sack not shown for purposes of illustration; 
       FIG. 3  is a perspective view of the invention and a disposable wood frame in release configuration, with netting sack not shown for purposes of illustration; 
       FIG. 4  is a front elevation view of the invention holding a disposable wood frame in raising and lowering configuration, with netting sack not shown for purposes of illustration; 
       FIG. 5  is a front elevation view of the invention and a disposable wood frame in release configuration, with netting sack not shown for purposes of illustration; 
       FIG. 6  is a detail perspective view of the invention holding a disposable wood frame in raising and lowering configuration, with netting sack not shown for purposes of illustration; 
       FIG. 7  is a detail perspective view of the invention holding a disposable wood frame in release configuration, with netting sack not shown for purposes of illustration; 
       FIG. 8  is a front elevation view of a second embodiment of the invention; 
       FIG. 9  is a front elevation view of a third embodiment of the invention; 
       FIG. 10  is a front elevation view of a fourth embodiment of the invention; 
       FIG. 11  is a front elevation view of a fifth embodiment of the invention; 
       FIG. 12  is a front elevation view of a sixth embodiment of the invention; 
       FIG. 13  is a top plan view of the embodiment of the invention shown in  FIG. 12 ; 
       FIG. 14  is a cross-section view taken along lines A—A of  FIG. 12 ; and 
       FIG. 15  is a cross-section view taken along lines B—B of FIG.  12 . 
   

   DESCRIPTION 
   Throughout the following description, specific details are set forth in order to provide a more thorough understanding of the invention. However, the invention may be practiced without these particulars. In other instances, well known elements have not been shown or described in detail to avoid unnecessarily obscuring the invention. Accordingly, the specification and drawings are to be regarded in an illustrative, rather than a restrictive, sense. 
   With reference to  FIG. 1 , a lifting basket  10  is shown which is adapted for being removably held in place in a CSO floatables control system diverter frame. It has rear lifting lug  12 , and front lifting lug  14  to which cables  16 ,  18  can be attached. It has a handle slide gate  20  and guide rails  22  for guiding and holding the netting frame  28  ( FIG. 2 ) with attached netting sack  26  and frame lifting device  24 . The frame lifting device is sized to slide readily into and out of position between guide rails  22  of lifting basket  10 . 
     FIGS. 2 and 4  illustrate the disposable wooden netting frame  28 , with netting sack not shown, and attached frame lifting device  24  according to the invention. The frame lifting device  24  comprises a horizontal channel frame member  30  and two right-angle channel frame members  32 ,  34 . Preferably channel frame members  30 ,  32 ,  34  are made of stainless steel, but galvanized steel or other rust-resistant rigid materials such as rust-resistant metal, plastic, fiberglass or other synthetics are also suitable. They are sized to receive the netting frame  28 , which is constructed of “2×4”&#39;s, with a spacing of about ¼″ on either side of the 2×4 in the wider dimension, so the channel formed by the frame members have inner dimensions of about 4 inches by 1.5 inches. The lower end of the vertical members  50 ,  52  has a stop plate  55 ,  57  which extends across the 4 inch dimension of the channel but is only about 1 inch wide, in order to ensure that the net frame remains within the channel when being lifted. Horizontal channel frame member  30  has four projections  36  each provided with apertures  38  to receive removable hinge pins  40 ,  42 , which are secured in apertures  44 ,  46  in channel frame members  32 ,  34  by cotter pins  47 . Channel frame members  32 ,  34  comprise vertical channel members  50 ,  52  having angled corner ends  51 ,  53  and horizontal channel members  54 ,  56  which are welded to ends  51 ,  53 . Horizontal channel members  54 ,  56  are provided at either outer end thereof with projections  58 ,  60  each having apertures  62 ,  64  through which shackles  66 ,  68  of sling  70  are pivotally attached. Sling  70  further comprises a hoisting/release ring  72 , pivoting shackles  74 ,  76  connected through ring  72 , and cables  78 ,  80  secured to shackles  66 ,  74  and  68 ,  76  respectively. Horizontal channel members  54 ,  56  are further provided at either inner end thereof with projections  81 ,  82  extending at right angles to members  54 ,  56  and each having apertures  84 ,  86  through which lifting shackle  88  pivotally and removably extends. Apertures  38  are preferably positioned relative to members  54 ,  56  so that the lower ends members  50 ,  52  will pivot towards each other when lifting shackle  88  is raised, but the invention will also work if apertures  38  are positioned relative to members  54 ,  56  so that the lower ends members  50 ,  52  do not pivot when lifting shackle  88  is raised. 
   Hoisting/release ring  72  is selectively connected to or released from lifting shackle  88  by a snap shackle  90 . Snap shackle  90  has a pivoting hook  94  which moves between a snapped closed position as in FIG.  6  and an open position as in  FIG. 5  when released by pulling release ring  92 . A frame release cord  96  having a stainless steel trigger snap  98  is connected to release ring  92  as shown in  FIG. 5  to remotely release the snap shackle  90 . Vertical members  50 ,  52  have slots  99  into which a screwdriver or the like can be inserted to pry the wooden frame out of the channel members  50 ,  52  if necessary. 
   In operation, a new disposable wooden netting frame  28  is positioned within frame lifting device  24  as shown in  FIG. 2 , and is held generally in place by a friction fit. Snap shackle  90  is snapped shut to connect hoisting/release ring  72  to lifting shackle  88 . A cable from a hoist is then secured to hoisting/release ring  72  to lift the new netting frame and netting sack into place between guide rails  22  as shown in FIG.  1 . The lifting of ring  72 , lifting shackle  88  and projections  81 ,  82  causes right-angle channel frame members  32 ,  34  to rotate about hinge pins  40 ,  42  causing vertical members  50 ,  52  to be tightly squeezed against the wooden frame  28 . Once the new frame  28  and frame lifting device  24  are in place between guide rails  22 , the lifting cable is removed from hoisting/release ring  72 . When the netting sack needs to be replaced, a lifting cable is again attached to ring  72  and the frame lifting device  24  and attached frame  28  are lifted out of the guide rails  22  and onto the disposal truck. The disposable frame  28  is then removed by pulling frame release cord  96 , which allows snap shackle  90  to release from ring  72 . The weight of the device on points  58 ,  60  then causes members  32 ,  34  to rotate about pins  40 ,  42 , thereby removing device  24  from the frame  28  and allowing the disposable frame  28  and netting sack  26  to fall away and be discarded. While the invention has been described using a snap shackle  90  for quick release, the invention will also work using a regular shackle which is manually released instead of a snap shackle. 
   In the embodiment of the invention shown in  FIG. 8 , the frame lifting device is designated by numeral  100 . Vertical channel members  102 ,  104  are hingedly connected to a horizontal channel member  106  at hinges  108 ,  110 . As in the previous embodiment, the channel members are sized to slide readily into and out of position between guide rails  22  of lifting basket  10 , and to receive the netting frame  28 . The interior surfaces of the channels are shown in phantom outline. Lugs  112 ,  114  are secured to the upper end of vertical members  102 ,  104  and are provided with holes  116 ,  118  to which lifting cables  120 ,  122  can be attached. A stop plate  124 ,  126  is provided across the vertical channels to prevent the wooden frame from floating out of the channels. Snap shackle  128  allows one of the cables  120  to be remotely detached from the frame lifting device  100 . In operation, in this embodiment a new disposable wooden netting frame  28  is positioned within frame lifting device  100  and cables  120 ,  122  are secured to lugs  112 ,  114  to lift the new netting frame and netting sack into place between guide rails  22  as shown in FIG.  1 . When the netting sack needs to be replaced, cables  120 ,  122  are again secured to lugs  112 ,  114  to lift the netting frame and netting sack and lifting frame  100  out of the guide rails  22  and onto the disposal truck. The disposable frame  28  is then removed by releasing shackle  128  which then causes members  102 ,  104 ,  106  to rotate about hinges  108 ,  110 , thereby allowing the disposable frame  28  and netting sack  26  to fall away and be discarded. 
   In the embodiment of the invention shown in  FIG. 9 , the frame lifting device is designated by numeral  130 . Vertical members  132 ,  134  and horizontal member  136  are formed of 90-degree angle iron and are rigidly welded at right angles as shown in FIG.  9 . The vertical members are sized to slide readily into and out of position between guide rails  22  of lifting basket  10 , and to receive the netting frame  28  from the direction extending into the page in FIG.  9 . Hinged tabs  138  are provided which swing outwardly or rotate as shown in  FIG. 9  to permit the netting frame to be introduced into or removed from the lifting frame. Hinged tabs  138  can be secured in the position shown in  FIG. 9  by a spring or latch to hold the netting frame within the lifting frame  130 . Lugs  139 ,  140  are secured to the upper end of vertical members  132 ,  134  and are provided with holes to which lifting cables  142 ,  144  can be removably attached. Stop plates  146 ,  148  are provided across the vertical members to prevent the wooden frame from floating out of the channels. In operation, in this embodiment, hinged tabs  138  are opened and a new disposable wooden netting frame  28  is positioned within frame lifting device  130 . Cables  142 ,  144  are secured to lugs  139 ,  140  to lift the new netting frame and netting sack into place between guide rails  22  as shown in FIG.  1 . When the netting sack needs to be replaced, cables  142 ,  144  lift the netting frame and netting sack and lifting frame  130  out of the guide rails  22  and onto the disposal truck. The disposable frame  28  is then removed by opening hinged tabs  138  by rotating or swinging them, thereby allowing the disposable frame  28  and netting sack  26  to be discarded. 
   In the embodiment of the invention shown in  FIG. 10 , the frame lifting device is designated by numeral  150 . It comprises two opposed C-shaped channel members  152 ,  154  which are open on one side and sized to receive the netting frame  28  between them. The interior surfaces of the channels are shown in phantom outline The vertical portions  156 ,  158  of members are sized to slide readily into and out of position between guide rails  22  of lifting basket  10 . Lugs  160 ,  162  are secured to the upper inner ends of opposed C-shaped channel members  152 ,  154  and are provided with holes to which lifting cables  163 ,  164  can be attached. In operation, in this embodiment, a new disposable wooden netting frame  28  is positioned within frame lifting device  150 . Cables  163 ,  164  are secured to lugs  160 ,  162  to lift the new netting frame and netting sack into place between guide rails  22  as shown in FIG.  1 . When the netting sack needs to be replaced, cables  163 ,  164  are used to lift the netting frame and netting sack and lifting frame  150  out of the guide rails  22  and onto the disposal truck. The disposable frame  28  is then removed by removing the tension from cables  163 ,  164  and spreading members  152 ,  154  thereby allowing the disposable frame  28  and netting sack  26  to be discarded. 
   In the embodiment of the invention shown in  FIG. 11 , the frame lifting device is designated by numeral  170 . It comprises two vertical channel members  172 ,  174  which are open on the inwardly-facing side and sized to receive the netting frame  28  between them. The interior surface of the channel and spikes, as discussed below, are shown in phantom outline. As in the previous embodiments, the channel members are sized to slide readily into and out of position between guide rails  22  of lifting basket  10 , and to receive the netting frame  28 . Lugs  176 ,  178  are secured to the upper end of vertical members  172 ,  174  and are provided with holes  180 ,  182  to which lifting cables  184 ,  186  can be removably attached. Stop plates  188 ,  190  are provided across the vertical channels to prevent the wooden frame from floating out of the channels. In operation, in this embodiment the vertical members are positioned on opposing frame members of a new disposable wooden netting frame  28 . Spikes  192 ,  194  hold the vertical members on the wooden frame members. Cables  184 ,  186  are secured to lugs  176 ,  178  to lift the new netting frame and netting sack into place between guide rails  22  as shown in FIG.  1 . When the netting sack needs to be replaced, cables  184 ,  186  are secured to flanges  176 ,  178  to lift the netting frame and netting sack out of the guide rails  22  and onto the disposal truck. The disposable frame  28  is then removed by removing the tension from cables  184 ,  186  and removing disposable frame  28  from members  172 ,  174  thereby allowing the disposable frame  28  and netting sack  26  to be discarded. 
   In the embodiment of the invention shown in  FIGS. 12 through 15 , the frame lifting device is designated by numeral  200 . Vertical members  202 ,  204  and horizontal member  206 ,  208  are formed of 90-degree angle iron and are rigidly welded at right angles as shown in  FIG. 12  to form a rigid rectangle or square. Retaining plates  210 ,  212  are welded to horizontal member  208  to retain netting frame  28 . The vertical members  202 ,  204  are sized to slide readily into and out of position between guide rails  22  of lifting basket  10 , and device  200  is sized to receive the netting frame  28  from the direction extending into the page in FIG.  12 . Moveable pin  214  slides vertically in an aperture in mounting plate  216  and is biassed downwardly by spring  218 . By pulling pin  214  to the upper position, the netting frame  28  is permitted to be introduced into or removed from the lifting frame  200 . Lugs  220 ,  222  are secured to horizontal member  206  and are provided with holes to which lifting cables (not shown) can be removably attached. In operation, in this embodiment pin  214  is raised, a new disposable wooden netting frame  28  is positioned over retaining plates  210 ,  212  within frame lifting device  200  and pin  214  is lowered to retain netting frame  28  within frame lifting device  200 . Cables are secured to lugs  220 ,  222  to lift the new netting frame and netting sack into place between guide rails  22  as shown in FIG.  1 . When the netting sack needs to be replaced, cables lift the netting frame and netting sack and lifting frame  200  out of the guide rails  22  and onto the disposal truck. The disposable frame  28  is then removed by raising pin  214  thereby allowing the disposable frame  28  and netting sack  26  to be removed and discarded. 
   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.