Patent GB-882961-A (GB)
Title: Improvements in or relating to apparatus for computing suitable disposition of cargoin ships
IPC: G06G1/14
Filed: 1959-08-25
Abstract: 882,961. Mechanical calculating-apparatus. KOCKUMS MEKANISKA VERKSTADS A.B. Aug. 25, 1959 [Aug. 30, 1958], No. 29035/59. Class 106 (1). A mechanical device for computing the effect of the disposition of the cargo of a ship comprises a casing bearing indices, a number of weight scales each associated with an index and adjustable so as to indicate the weight of cargo in each compartment of the ship, a graph (of " mean draught " against " alongship stresses in an athwardship plane " plotted for different loads) associated with an index and a stress pointer and adjustable in the " draught " direction, a setting member outside the casing which may be connected by a first driving means with any one of the weight scales, by a second driving means with the graph, and by a third, variable gear, driving means to the stress pointer, and a selector which simultaneously engages one of the weight scales with the setting member and selects a gear ratio of the third driving means such that the movement of the stress pointer is proportional to the moment of the selected weight about the chosen athwardship plane. The device comprises a system of gears, whereby the rotation of a knob 13, Figs. 2, 6, causes the graph drum 26, a friction drive cylinder 54, and cones 51a 51b to rotate, the rotation of the two cones being equal. A wheel 66 may be brought into contact with a particular portion of the cone when a weight indicator wheel 21 makes contact with the friction cylinder 54. Rotation of wheel 66 rotates shaft 62, which rotation is passed by non-slidable gears to lead screw 64 carrying a captive nut 70 to which is secured the stress pointer 34. Wheel 66 also drives lead shaft 72, through gears 68b; 71, bearing a captive nut 73 carrying the trim pointer 33. However, trim is dependent upon the direction of the turning moments as well as their magnitude. In this case the gear 71 is arranged to disengage from wheel 68b and engage instead wheel 69b (which rotates screw 72 the same distance in the opposite direction) as a selector 14 passes the mid-point of the ship. The top of the device comprises a diagram of the ship and its compartments, Fig. 1, below which is a slot 15 along which the selector 14 may move. Notches 18 and weight indicator wheels 21 are positioned to correspond with the centre of gravity of each compartment. When selector 14 is pushed into a notch 18, corresponding to a specific compartment, a lever arrangement, Fig. 4, brings a weight indicator 21 into contact with the friction drive 54, and wheel 66 into contact with cone 51a. Knob 13 is turned until the weight to be placed in this particular compartment is aligned with the index line on the corresponding weight indicator. Trim, stress, draught and deadweight scales, along with trim and stress indicators, move to their appropriate position (previously determined when designing graph and gearing arrangements). The operation is repeated for each compartment of the ship. Each time the selector passes the centre compartment its stem 59 trips a lever arrangement 75, 76 and 77, Fig. 8, which shifts gear 71 and changes the direction of rotation of shaft 72, thus adding and subtracting moments as required. A number of refinements are suggested, one being an arrangement of rubber strips which wheels 21 will contact when not in contact with friction drive 54. Further, as wheels 21 leave the friction drive a rubber block 83, Fig. 4, on a lever arrangement contacts the graph drum 26 and arrests it. The cones 51 may be replaced by a system of gear assemblies, Fig. 9 (not shown), which serve the same purpose whilst preventing inaccuracies due to slipping between the members. Zeroizing.-In a modification arranged to facilitate zeroizing of the mechanism, the slot 15, Fig. 1, is extended to the left and the selector 14 may be moved into a zeroizing notch. This movement effects the disengagement of the graph cylinder 26 and of the shafts driving the trim and stress pointers, all of which may then be zeroized by corresponding knobs. All of the indicating drums 21, Fig. 1, or 121, Figs. 14 and 16, may be zeroized simultaneously by rocking a lever 228 connected, through a pawl 231 and ratchet wheel 230 and gears 229, 236, to rotate a shaft 237 through one revolution. Pins 240 on the shaft 237 engage abutments 239 of wheels 238 geared to the drums 121 so as to advance the latter to their zero positions. Specification 669,553 is referred to.