Gangway construction
United States Patent [191 Mampaey GANGWAY CONSTRUCTION [76] Inventor: Johannes Josephus Mampaey,  
 Wijnstraat l l, Dordrecht. Netherlands [22] Filed: Feb. 8, 1974 [2|] App]. No.: 440,663  
 [30] Foreign Application Priority Data Feb. 9. 1973 Netherlands 730l878 [52] US. Cl. 14/71 [5 l] Int. Cl. 865g 11/00 [58] Field of Search l4/7l, 72  
 [ 1 Apr. 8, 1975 [56] References Cited UNITED STATES PATENTS 785,400 3/ I905 Buchanan l4/7l X I,778.667 l0/I930 French.......... l4/7l l.778,847 10/!930 Dalin 14/72 1.960.355 5/1934 Tamini l4/7l X Primary ExaminerNile C. Byers, Jr. Attorney, Agent, or F irm- O&#39;Brien &amp; Marks [57] ABSTRACT A gangway is connected on one end to an annular platform surrounding, and movable up and down a spiral staircase.  
 6 Claims, 4 Drawing Figures I -12&#39; 14 1r 7| l a PATENTED APR 8 7 SHEET 2 0g 3 FIG. 2  
 FIG. 3  
  1 GANGWAY CONSTRUCTION The invention relates to a gangway construction, in particular for boarding and leaving tankers, comprising a tower and a gangway at one end is vertically movable along the tower.  
  The rising and falling of the tide as well as the loading and unloading of vessels, in particular tankers, cause a continuously varying difference in height between the quay and the deck of the moored vessel. In order to obtain a suitable connection between shore and vessel in the known constructions, the one end of the gangway is from time to time moved to a higher or lower entrance in the tower, which is cumbersome. Moreover, while the gangway is being moved from one entrance to another, no passage is possible, which may be dangerous in an emergency, for example in the case of breakdown of the moving apparatus.  
  It is an object of this invention to eliminate the above drawbacks.  
  According to the present invention there is provided a gangway construction, in particular for boarding and leaving tankers, comprising a tower and a gangway which at one end is movable vertically along the tower, characterized by an annular platform movable upwards and downwards together with said one end of the gangway, said platform surrounding a spiral staircase disposed in the tower. With the construction according to the invention it will be possible to continuously adjust the height of the platform to the difference in height between quay deck and the variation of said difference, while furthermore said platform will be accessible from one or more of the steps of said staircase at any mo ment during movement thereof. In a certain position of said platform, the steps accessible therefrom serve as a kind of intermediate platform between said platform and the other steps of said sprial staircase.  
  While a vessel is moored, the difference in height between the deck on which the gangway rests and the quay may vary continuously, in particular during loading or unloading of the present-day mammoth tankers. Owing to the varying difference in height, the platform height should be continuously adjusted to provide for convenient and safe passage. For this purpose according to a further elaboration of the invention there is provided a control system adapted to adjust the platform height and to automatically maintain the angle of inclination of the gangway within a predetermined range. According to a preferred embodiment of said control system it is responsive to the angle of inclination of the gangway.  
  In order to make it easy to step from the platform on the steps of the staircase and vice versa, according to a further elaboration of the invention the control system is preferably so designed that the platform always stops flush with a step of said staircase.  
  One preferred embodiment of the invention will now be described with reference to the accompanying drawings wherein:  
  FIG. 1 shows schematically a gangway construction comprising a gangway, a crane, a control room and a service room when in use;  
  FIG. 2 shows schematically a cross-section on the line II--II of FIG. 1;  
 FIG. 3 shows a detail to a larger scale; and  
  FIG. 4 shows schematically an arrangement for supporting the platform.  
  Referring to the drawings, the embodiment of the gangway-tower construction as shown comprises a tower 2 founded on a quay I. Around the base of the tower 2 there are disposed service rooms 3, while at the top of said tower there are arranged a control room 4 topped by a hoisting crane 5. Around tower 2 there is an annular platform 6 which is movable up and down.  
  A gangway 7 is hinged to platform 6 and is provided with a stairway at the end remote from platform 6. Owing to said stairway the gangway 7 can rest on deck 8 ofa vessel 9 free from any obstacles present thereon, e.g. the railing. For reasons of convenience and safety the horizontal embodiment of gangway 7 is much to be preferred to an inclined one. The floor of gangway 7 may be made of wood, aluminum sheet or the like, and be provided on either side with a railing.  
  Since the vessel does not stay in the same position relative to the quay, there are mounted at the bottom end of the stairway of gangway 7 swivelling wheels I0, by means of which gangway 7, when in use, rests on deck 8 of vessel 9. Moreover, the connection between platform 6 and gangway 7 is such as to enable rotation of the gangway about a vertical axis (FIG. 2). A rotation capacity of 25 to either side is already sufficient.  
  When the gangway is out of operation, it can be hoisted by means of eg a hydraulic plunger 11 which is disposed between gangway 7 and platform 6. It is also possible, however, to use a hoist instead of hydraulic plunger 11.  
  The tower 2 comprises a hollow column 12 around which are arranged twelve I-shaped sections 13 in a concentric circle. Between said I-shaped sections 13 and the column 12 there are positioned the steps of a spiral staircase 14. Four of the sections I3 should be very accurately positioned (FIG. 2). On said four sections there are mounted guides 15 (FIG. 3) serving as guideways for the platform.  
  The platform 6 is a hexagon built up from 6 elements, covered with aluminium sheet and provided the outer edge with a railing.  
  At one side of the platform 6 the gangway 7 is mounted for vertical and horizontal pivoting movement. Naturally, the platform should be so constructed as to prevent limbs from getting wedged between the platform 6 and the tower 2. This is possible e.g. by installing a railing along the inner edge of the annular platform, which railing is so turned during the lifting or the lowering of the platform that there is always an opening in the railing opposite that step of the spiral staircase which lies at the level of the platform. The platform is guided by four pairs of spring-supported nylon rollers 16. Each of the four pairs of rollers 16 rolls over one guide 15, which is shown schematically in FIG. 3.  
  The platform 6 is suspended from four double ropes 17 which, via pulleys (not shown) in the top of the tower are connected to a counterweight 18 within column 12 (FIG. 4). The counterweight 18 serves for compensating the weight of the platform and the gangway, thus reducing the weight to be moved, but must not be heavier than that of the platform. The couterweight 18 is provided with a known per se catching mechanism I9 to which are connected ropes 20. The counterweight catching mechanism 19 serves for protection in the case of breakage of ropes. The other ends of the ropes 20 are wound on a winch drum 21 provided with hydraulic laminated brakes 22 and driven by a hydraulic motor 23. Through this design of the entire arrangement the motor 23 only needs to move the difference in weight between the loaded platform and the counterweight.  
  To safeguard platform 6 against failure of the suspension gear. said platform is provided with four known per se catching units which, when actuated, firmly grip the four guides on the tower 2.  
  In use. the platform height is adjusted fully automati cally: if the angle of inclination of gangway 7 exceeds or falls below a pre-determined value. a switch is mechanically operated to actuate winch 21 so that platform 6 is moved upwards or downwards. The winch continues to operate until the gangway is approximately horizontal and level with one of the steps of the spiral staircase. This movement is rather slow (about 0.8 m/minute), so that even during said movement it is possible to step from the staircase onto the platform and vice versa.  
  For rapid lifting and lowering of the platform. which may be necessary when the gangway 7 is lowered to form a passageway to the vessel 9., the winch motor can be operated by means of a hand-actuated control system. There may also be provided in the tower an elevator which is adapted to move from the platform to the quay and vice versa and which is so designed as to stop at the level of the platform and to follow the move ment of said platform. Such elevator may also be positioned outside the tower and beside the platform.  
 I claim:  
  1. A gangway construction, in particular for boarding and leaving tankers, comprising a tower and a gangway which at one end is movable vertically along the tower, characterized by an annular platform movable upwards and downwards together with said one end of the gangway, said platform surrounding a sprial staircase disposed in the tower.  
  2. A gangway construction according to claim 1, wherein a control system adjusting the platform height keeps the angle of inclination of the gangway automatically within a pre-determined range.  
  3. A gangway construction according to claim 2, wherein the control system adjusts the platform height in response to the angle of inclination of the gangway.  
  4. A gangway construction according to claim 3, wherein theplatform always stops at the level of the step of said staircase.  
  5. A gangway construction according to claims 1, wherein the gangway is rolable in horizontal direction relative to the gallery platform.  
  6. A gangway construction according to claims 1, wherein there is disposed along the inner edge of the gallery platform a railing which is so turned during the lifting or the lowering of the platform that there is always an opening in the railing opposite that step of the spiral staircase which is flush with the platform.