John T. Hepburn, Limited

Ronald Ballantyne

Leon Malashenko

Martin Murray

Derek Foster

Press platens are maintained parallel in critical central regions proximate to a mold between the platens. Leveling cylinders acting between the platens to resist downward action of a central ram on a movable platen. Data identifying expected local platen deflection in response to various operating pressures of the leveling cylinders are recorded. For each leveling cylinder, the current operating pressure is determined and the relative spacing of the platens proximate to the leveling cylinder is sensed. The operating pressures of the cylinders are controlled in response to the sensed relative spacing of the platens and in response to the expected local platen deflection for each leveling cylinder at its current operating pressure to maintain a substantially parallel relationship between the platens proximate to the mold. The platen deflection data required for each leveling cylinder are obtained in a preliminary process involving operation of the platens to compress the mold, operating the leveling cylinders at their various operating pressures, and sensing and recording local platen deflection that results.

Maintaining press platens in parallel relationship

In an anchoring system for a floating vessel which includes an anchor line comprising chain cable, a chain locker and a windlass having a chain wheel that conveys the chain cable during paying out from the chain locker, a mechanism is positioned between the chain locker and chain wheel to back-tension the chain during paying out. The mechanism has an axis along which the chain is passed with every second links oriented in a given plane. Paired brake shoes are positioned to either side of the plane and define braking surfaces of sufficient extent along the axis of chain movement that a given chain link and an immediately succeeding link of similar orientation can be simultaneously engaged during their movement to provide a continuous retarding effect. One pair of braking shoes is pivotally mounted on an appropriate support structure and urged with hydraulic cylinders towards the other pair thereby causing the brake shoes to engage the opposing faces chain link. The pressure of hydraulic fluid applied to the cylinders is adjusted to back-tension the chain sufficiently that sudden shocks to the windlass otherwise occasioned by tilting and jumping of chain links during conveyance over the chain wheel are avoided. Non-standard links and irregularities in the chain link surfaces such as weld lines are accommodated by contraction of the hydraulic cylinders and deflection of the pivoting brake shoes.

Mechanism for tensioning a moving chain

An anchoring system for a floating structure is described. The anchoring system is of the type which employs a combination anchor line consisting of a lower length of chain cable connected to an anchor and an upper length of wire rope and which involves disconnection of the wire rope from the chain cable during paying out and retrieval of the anchor line. A winch and windlass mounted on the floating structure serve to separately haul in and pay out the wire rope and chain cable, respectively. The windlass has a length of lead chain which can be used to lead the chain cable over a chain wheel to the chain locker. An overwide chain link terminates the chain cable, and together with a pair of detachable links permits the load of the chain cable to be transferred directly from the winch to the windlass, during paying out and retrieval, without the requirement for an intermediate chain hanger. The fairlead sheave and the chain wheel associated with the windlass are designed to convey the overwide chain link as if it were any other link in the chain line, and consequently no swivels or other special measures are required to ensure that the overwide chain link is properly conveyed over these devices.

Anchoring system for floating structure

An anchoring system for semisubmersible drill rigs is described which includes a wire rope-chain cable anchor line and in which system components co-operate to convey the junction of the wire rope and chain cable smoothly over a fairlead sheave. The connector joining the anchor line has a narrow end in which the rope is rigidly retained, a large end at which a chain end link is pivotally retained, and a radially symmetric, generally concave surface extending between the two connector ends. The outer surface of the connector is shaped to seat against the central hub of the fairlead sheave in a predetermined orientation in which a limited fixed bend angle is formed between the connector and the wire rope. The geometry of the connector naturally biases the connector to seat against the central hub of the fairlead sheave in the predeterminted orientation during hauling in of the anchor line. A collar fitted about the penultimate chain link displaces the large connector end from the sheave during paying out of the anchor line until the outer connector surface can be drawn by the wire rope into engagement with the sheave. Wire rope bending is accordingly minimized without significantly enlarging or altering the size of the fairlead sheave.

A press has upper and lower platens which can be moved towards and away from one another. Four hydraulic leveling cylinders are mounted in a vertical orientation on the lower platen for purposes of platen parallelism control. In preferred form, each cylinder has a piston rod which engages an associated post on the upper platen as the platens approach one another. The piston rod and associated piston are formed with a longitudinal bore open at the upper piston rod end, and a rigid shaft is mounted in the bore with a lower end extending through the bottom of the cylinder housing. A coil spring in the interior of the piston rod urges the rigid shaft upwardly until a collar formed on the shaft engages a stop surface, the upper shaft end then being flush with the upper piston rod end. The associated post is fixed to the upper press platen in-line with the piston rod and has an internal passage in which is located a stud-like shaft that engages the rigid shaft mounted in the piston rod. Changes in the spacing between platens, including changes attributable to axial contraction and expansion of the post and piston rod with varying applied loads, are consequently manifested as axial displacement of the lower end of the rigid shaft relative to the lower platen. A sensor detects this relative displacement, producing a signal indicating platen spacing at the leveling cylinder. Sensor signals from the four cylinders are used to control the cylinders so as to maintain platen parallelism.

Hydraulic cylinder device for platen spacing indication and control

A hydraulic press is adapted to permit adjustment of the clearance between upper and lower platens and to permit the press to be divided into distinct upper and lower sections for purposes of transport. The press has four vertical posts which extend upwardly from the lower platen. Each post has a lower section which slides in the lower platen, an upper section is fitted into and slides relative to the upper platen, and a releasable joining structure which connects the post sections to define a unitary post structure. Light-duty hydraulic cylinders permit gross positioning of the upper platen on the posts. The upper platen is then locked to the upper post sections in a predetermined relative position, and heavy-duty hydraulic cylinders acting on the posts serve to draw the upper platen towards the lower platen to compress a work piece. When platen clearance is to be adjusted, the joining structures are released, hydraulic cylinders formed in the interior of each lower post portion are actuated to raise the associated upper post portions, and the upper platen is supported from the lower platen by mechanical blocks. Mechanical spacers retained by the joining structures are then replaced with spacers of different height thereby adjusting maximum platen clearance. Also, when the joints are released, the press effectively divides into upper and lower sections which can be more conveniently transported.

Press with adjustable platen spacing

An integrated winch and windlass for hauling in and paying out a mooring line which consists of wire rope serially connected to chain cable is described. The integrated system has a pair of traction winch drums for conveying the wire rope, and a chain wheel for conveying the chain cable. The chain wheel is coaxially mounted with one traction winch drum, and has a wire rope groove with a groove diameter substantially the same as that of the traction winch drums. A sheave directs wire rope between one of the drums and the chain wheel, and is so positioned that a wrap of wire rope is formed about the chain wheel whenever the system is operating on wire rope exclusively. A drive mechanism is provided for rotating the traction winch drums and chain wheel, including a common drive shaft, and a clutch mechanism which permits the traction winch drums and the chain wheel to be located simultaneously or separately. Simultaneous rotation of the chain wheel and traction winch drums is timed so that wire rope is conveyed at the same speed by the traction winch drums and the chain wheel. The chain wheel is effectively integrated into the traction winch functions, the wire rope groove of the chain wheel basically serving as the first groove of a traction winch.

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Burlington, Canada

Ronald Ballantyne