Patent Number: 052951677
Section: description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, the service pole caddy system 2 in accordance with the preferred embodiment of the invention comprises a rigid frame made up of welded tubes. The rigid frame comprises right and left frames, each comprising a vertical tube 4, an oblique tube 6, a vertical tube 8, an oblique tube 10, a horizontal tube 12 and a horizontal tube 14. The right and left frames are connected by four horizontal tubes 16. The rigid frame is mounted on a truck 18 via plate 19. Truck 18 rides on a rail 20 which is supported by an I-beam 22 of the refueling bridge, as shown in FIG. 2. A monorail hoist 24 has a motorized trolley which rides on an I-beam 26 supported by the rigid frame. The travel of hoist 24 is stopped at the ends of I-beam 26 by respective stop angles 28. The maximum travel of the hoist may be about 46 feet or any other length depending on the dimensions of the specific reactor with which the pole caddy system is used. The hoist 24 includes a control box 30 and a hook 32 which is coupled to a pole connector to be described in detail below. As best seen in FIGS. 3 through 5, the rigid frame further comprises a rigid structure welded to tubes 4 for supporting the pole service caddy. This structure includes two vertical tubes 34 separated by a distance equal to the distance between tubes 4; two horizontal tubes 36 each welded at respective ends to a tube 4 and a tube 34; a horizontal tube 38 welded at respective ends to tubes 4; and a horizontal tube 40 welded to one of the tubes 34 and parallel to horizontal tube 38. Horizontal tubes 38 and 40 are in turn joined by an angle 42. As shown in FIG. 4, a lower rack 44 is welded into the rectangular space defined by tubes 36, 38, 40 and angle 42. Lower rack 44 is a four-by-two array of tubular cells of square cross section, each tubular cell being designed to receive one end of a generally upright service pole. Lower rack 44 has a perforated plate 45 (see FIG. 3) at the bottom which supports the ends of the service poles while allowing water from the poles to drain through and into the pool below. As shown in FIG. 5, the rigid structure further includes two horizontal angles 46 each welded at respective ends to a tube 4 and a tube 34; a horizontal angle 48 welded at respective ends to tubes 4; and a horizontal angle 50 welded to one of the tubes 34 and disposed parallel to angle 48. Horizontal angles 48 and 50 are in turn joined by an angle 52. An upper rack 54 is welded into the rectangular space defined by angles 46, 48, 50 and 52. Upper rack 54, like lower rack 44, is a four-by-two array of tubular cells of square cross section, each tubular cell being designed to receive a mid-portion of a generally upright service pole. The upper rack is supported by a channel member 56, which is welded to tube 40 at the lower end and to angle 50 at the upper end. The lower and upper racks are positioned in alignment at different elevations and together maintain the service poles 58 in a generally vertical storage position, one pole to a cell, as shown in FIG. 6. In an exemplary embodiment, each cell has a width of 31/4 inches, whereas each pole has an outer diameter of 21/2 inches, allowing for easy storage and removal. The frame shown in FIG. 5 further comprises a keyway plate 60, which is swingably mounted on a hinge 61 welded to angles 48 and 52. In the down position, keyway plate 60 has a portion which rests atop angle 48 and is supported thereby. Keyway plate 60 has a two-position slot 62 with two throats 68, 70 of width less than the outer diameter of the service poles, but greater than the diameter of the neck of the pole end connector (to be described in detail below). At a first position, slot 62 has opposing recesses 64 which are arcs of a circle of radius 11/2 inches. The tubing of a service pole intersecting the slot 62 and positioned between recesses 64 cannot be displaced laterally except for a small amount of play. This play allows for guided vertical displacement of the pole when in position B shown in FIG. 6. The slot 62 ends at a second position in a semicircle 66 of diameter 21/8 inches, which is slightly greater than the pole neck diameter but less than the pole outer diameter. The upper edge of slot 62 at the second position is chamfered to form a seat 72 which supports a service pole in position C shown in FIG. 6. As best seen in FIG. 6, the service poles 58 are lifted, lowered and carried by means of hoist 24, which is an electric hoist with a motorized trolley that rides on monorail 26. The hoist has a coupling 74 adapted to couple with the end connector of a service pole. A service pole 58 can be lifted out of the storage caddy, carried laterally and then lowered into guided pole handling position B. A pole in position B can be moved into pole assembly position C by first displacing the pole vertically while in position B until its neck is lined up with slot 62 and then pushing the pole so that its neck passes through throat 68. When the pole overlies position C (see FIG. 6), the pole is lowered until its seating portion abuts and is supported by support seat 72. Then another pole can be retrieved from the caddy and placed directly over the pole being supported in position C. Thereafter the bottom end connector of the second pole is coupled to and locked on the top end connector of the pole being supported in position C. This operation is repeated until the multi-pole assembly is completed. The multi-pole assembly can then be carried by the hoist to open pole handling position A and lowered as necessary to line up the tool, mounted on the lower end of the assembly, with the component to be manipulated by the tool. The service pole position is also determined by the position of the movable rigid frame. As previously described, the rigid frame is mounted on truck 18, which rides on rail 20 supported by I-beam 22 of the refueling bridge. Some of the components of truck 18 are shown in FIGS. 9A and 9B. The truck has two wheels 118 mounted on respective shafts 120. Other truck components include four bearings 122, four spacers 124, four hold-down plates 126, two rubber wiper rails 128 and four cam followers 130. The rigid frame, in addition to riding on a rail supported by the refueling bridge I-beam, is also provided with a pair of wheels 76, 76' and a pair of casters 78, 78' (see FIG. 1). As best seen in FIG. 2, wheels 76 and 76' ride on a lower leg of a refueling bridge channel 80, while casters 78, 78' bear against the vertical central member of channel 80. The casters 78, 78' are supported by wheel support 84, which is an angle welded to vertical tubes 4 (see FIGS. 1 and 7). The wheels 76, 76' are supported by brackets 82 via hubs 86 (see FIG. 7). Brackets 82 are welded to horizontal tube 38. Referring to FIG. 3, the frame further comprises two supporting angles 88, each supporting angle being welded to a vertical tube 4 and a vertical tube 34. Angles 88 support the auxiliary personnel work platform, which is generally designated by numeral 90 in FIG. 8. The work platform 90 is generally L-shaped, the two legs of the L being situated adjacent two sides of the pole storage station. The work platform has a welded base frame comprising angles 92, 94, 96, 98, 100, 102 and channels 104, 106. This base frame has a floor plate 108 welded thereon, on which the personnel stand. The perimeter of the work platform has a front railing 110 and two side railings 112, as best seen in FIG. 1. The perimeter of the base frame has a front kick plate 114 and two side kick plates 116 (see FIG. 8). Tubes 4, 6, 8, 34 and 36 are preferably 4".times.4".times.1/8"; tubes 12 and 14 are preferably 4".times.4".times.1/4"; and tubes 10, 16, 38 and 40 are preferably 3".times.3".times.1/8". All tubes can be made of ASTM A500 steel or any other functionally equivalent material. All angles referred to hereinabove are preferably 3".times.3".times.1/4" and can be made of ASTM A36 steel. The service poles used with the service pole caddy system of the invention have a diameter which is larger than that of conventional service poles. These large-diameter poles are designed to transmit torques adequate for all expected operations. The end connectors of these poles have a plug and socket design with a twist pin and a locking collar. This design maximizes the rigidity of the multi-pole assembly. Solid body end connectors are welded to each end of the poles to prevent contaminated water from entering the inside of the poles and to achieve pole buoyancy. Internal pole contamination is prevented and exterior decontamination can be easily accomplished. The solid body of each pole connector provides the equivalent shielding of eight feet of water in a four-pole assembly, thus preventing radiation streaming. Referring to FIG. 10, each service pole 58 comprises stainless steel tubing 134 with solid body end connectors 132 and 136 welded to respective ends thereof. End connector 132 has a pair of diametrally opposed, radially outwardly extending circular cylindrical twist pins 138 which cooperate with corresponding slots in locking collar 140 formed in end connector 136. The hoist 24 is provided with a coupling having twist pins identical to those on end connector 132 to enable the hoist to couple with the end connector 136 of any service pole which needs to be hoisted. Each end connector 132 is provided with threads 142. When threaded coupling 144 is screwed onto threads 142 of an end connector 132 coupled to an end connector 136, the connectors are effectively locked together. The pieces of the split ring are then attached to coupling 144, thereby preventing the coupling from being accidently screwed off and dropped into the reactor. Each end connector 136 has a neck 148 and a chamfered portion 150. When neck 136 passes through throat 68 of keyway plate 60 (see FIG. 5) to the second position, the pole is lowered until chamfered portion 150 rests on support seat 72, whereby the keyway plate supports the service pole, as indicated at position C in FIG. 6. The chamfered portion 150 form-fits with the chamfered support seat 72 such that lateral displacement of the chamfered portion 150 of the service pole seated thereon is resisted. The service poles can be of two different sizes. For example, one set of poles could have dimensions A and B (see FIG. 10) of 48 and 385/8 inches respectively, while another set of poles could have dimensions A and B of 96 and 865/8 inches respectively. The stainless steel tubing 134 has an outer diameter of 21/2 inches and a wall thickness of 0.083 inch. The preferred embodiment has been described for the purpose of illustration only. Various modifications of the service pole caddy system in accordance with the invention will be apparent to a skilled engineer. For example, the service pole caddy system disclosed herein can be readily adapted to cooperate with a refueling bridge having supporting structure different than that disclosed herein.