ELEVATING DEVICE FOR AN ARTIFICIAL ISLAND OR WORK PLATFORM

Abstract: Elevating device for an artificial island or work platform comprising a pontoon (1) or work floor and a number of columns (2) displaceable in vertical direction with respect to the pontoon (1) respectively the work floor by means of the elevating device. At each column (2) the elevating device consists of a number of driving devices having pinions (7-10) meshing in gear racks (3, 4) fixed along the columns (2). In particular concerning its bearing the shafts of the pinions (7-10) are fixed to the pontoon (1) or work floor and consist of a motor, a driving gear and a brake. Each driving device is fixed to respectively form part of a reaction arm (11-14) pivotable around the axis of the output shaft of the driving device. At its one end (15) the reaction arm (11-14) is coupled to the pontoon (1) or work floor through a hydraulic cylinder (23-26). At all of the reaction arms (11-14) the hydraulic cylinders (23-26) have a connection (39, 40) from both cylinder spaces to a common conduct (42) connecting all of the cylinders (23-26) to each other. Further, means are provided for moving simultaneously all of the valves (31-34) in the closed condition when the motors are put in operation respectively to open when the brakes are put in operation.

Description: Elevating device for an artificial island or work platform. The invention relates to an elevating device for an artificial island or work platform, comprising a pontoon or work floor and a number of columns displaceable in vertical direction with respect to the pontoon respectively the work floor by means of the elevating device, at each column said elevating device consists of a number of driving devices having pinions meshing in gear racks fixed along the columns, said driving devices in particular concerning the bearing of the pinion shaft, are fixed to the pontoon or work floor and consist of a motor, a driving gear and a brake. Such an elevating device is generally known. In said known elevating device one or more pinions mesh in each gear rack and usually, there are several gear racks per column with meshing pinions. Said pinions are driven either by hydraulic motors or by electric motors. During displacement of the pontoon or work floor with respect to the columns and inversely the forces acting on the pinions are automatically balanced. When the motors are stopped the brakes come into operation in which condition however, no balancing of the forces acting on the pinions and thus also on the gear racks exist anymore. The invention has the object to provide an elevating device whereby said latter may also be obtained completely. According to the invention said object is achieved in that each driving device is fixed to respectively forms part of a reaction arm pivotable around the axis of the output shaft of the driving device, said reaction arm is coupled at one end to the pontoon or work floor through a hydraulic cylinder, at all of the reaction arms said hydraulic cylinders have a connection from both of the cylinder spaces to a valve adapted to shut off said connection or to connect both of the cylinder spaces to a common conduct connecting all of the cylinders to each other and means are provided for moving simul¬ taneously all of the valves into the closed condition when the motors are put in operation respectively to open when the brakes are put in operation. In the braked condition the hydraulic connection between the cylinders of the reaction arms performs the compensation of dif- ferences in forces. Now, the invention will be elucidated with reference to the OMPI drawings . Fig. 1 shows the principle of the invention. Fig. 2 is partly a view and partly a horizontal section through a driving device of the elevating device according to the invention. Fig. 1 shows part of a pontoon 1 and a column 2 provided with gear racks 3 and 4 respectively at two opposite edges. On the pontoon a derrick is provided indicated by the parts 5 and 6 schematically. The circles 7, 8, 9 and 10 indicated by dash-dotted lines re- present pinions meshing in the gear racks 3 and 4 respectively. Pivo able around the axis of the pinions 7 up to and including 10 reaction arms 11, 12 , 13 and 14 are shown the ends 15, 16, 17 and 18 respectively of which are connected pivotably to the piston rods 19, 20, 21 and 22 of hydraulic cylinders 23, 24, 25 and 26. Said cylinders are pivotably fixed to the platform 1 as schematically indicated at 27, 28, 29 and 30. The reaction arms 11 upto and including 14 support the motor, brake and gear box not shown in Fig. 1. Near each cylinder 23, 24, 25 and 26 respectively a valve 31, 32, 33 and 34 respectively is situated movable from the open con¬ dition shown to the closed condition by means of operating means 35, 36, 37 and 38 shown in the upper half of the valves. In the open condition shown the space above the piston in each cylinder 23 upto and including 26is connected to the valve through the conduct 39, whereas the space below the cylinder is connected to the valve through the conduct 40 (see cylinder 23). In the open con¬ dition shown of the valves the conducts 39 and 40 communicates with each other as well as with a conduc 41, connecting the cylinders at both sides of a column respectively around the column to each other and connecting all of the cylinders to each other through a con¬ necting conduct 42 when several driving units are superposed. The conduct system 41, 42 may be supplied with pressurized liquid through a pressure conduct 43 having a one way valve 44 and an operating sliding valve 45. With said sliding valve 45 a liquid may be also drained off to the receptacle 46. The controlling is such'that duringthe operation of the elevat¬ ing device the connections between the cylinders 23 upto and includ- - Q «PI ing 26 are shut off. When the brakes cone into operation then the valves 31 upto and including 34 come into the open condition shown by which in all of the cylinders 23 upto and including 26 the same pressure ratios prevail and thereby the same loads between the pinions and the gear racks. At 47 rubber stops are shown limiting the parts of movement of the reaction arms. They may also be located at the lower side of the reaction arms. Said stops 47 may absorb the load during transport over sea, in which the cylinders are not pressurized. If desired in the hydraulic compensation system damping accumul- ators 48 may be provided. Fig. 2 shows a part of a column 2 with gear rack 4. Meshing in said gear rack is a pinion 7 the shaft of which is supported in bearings 50 and 51 fixed in the sections 52 and 53 of the derrick 6. A gear box 54 is fixed to said derrick in which gear box is located the large gear 55 supported on the pinion shaft and in meshing relation with the small gear 56 on the shaft of which a larger gear 57 is positioned cooperating with the small gear 58 on the shaft 59 of which the driving box 60 is fixed to which box a hydro otor 61 and a brake device 62 are connected. The box 60 is integral with the reaction arm 11 the end 15 of which is connected to the piston rod 19. Consequently, the box 60 with motor 61 and brake 62 as well as the reaction arm is pivotable around the axis of the small gear 58. By the high gearing obtained through the gear boxes 60 and 54, for compensation of differences in load at pinion and gear rack only relative low forces are to be .- expected in the reaction arms and thereby in the hydraulic compensat¬ ion system. If the elevating devices are in operation for raising the platform or lowering the columns then the compensation device is out of operation by holding the valves in the closed condition and the distribution of the driving forces of two or more driving units is effected hydraulically or electrically through a common supply of the motors. If the brake forces should be distributed, the valves are brought in the shown open condition by which the reaction forces on the reaction arms can balance each other. OMPI > W™IP P O O _-_,

Claims: CLAIM. Elevating device for an artificial Island or work platform com¬ prising a pontoon or work floor and a number of columns displaceable in vertical direction with respect to the pontoon respectively the work floor by means of the elevating device, at each column said elevating device consists of a number of driving devices having pinions meshing in gear racks fixed along the columns, said driving devices in particular concerning the bearing of the pini shaft, are on fixed to the pontoon or work floor and consist of a motor, a driving gear and a brake, characterized in that each driving device is fixed to respectively forms part of a reaction arm pivotable around the axis of the output shaft of the driving device, said reaction arm being coupled at one. end to the pontoon or work floor through a hydraulic cylinder, said hydraulic cylinders at all of the reaction arms having a connection from both of the cylinder spaces to a valve adapted to shut off said connection or to connect both of the cylin¬ der spaces to a common conduct connecting all of the cylinders to each other and means are provided for moving simultaneously all of the valves in the closed condition when the motors .are put in operat- ion respectively to open when the brakes are put in operation.

Inventors: SCHOONMADE WIM, SCHOONMADE, WIM
Applicants: RSV GUSTO ENG BV, GUSTO ENGINEERING B.V.
Application year: 1982
Main classification: E02B17
IPC codes: E02B17