Abstract: A liquid dashpot has a casing comprising a main body and bottom cover. The main body contains a liquid chamber which is divided into two discrete spaces by a vane member. One end wall of the chamber has porting passage means formed between the outer face of said wall and the bottom cover to provide restricted communication between the chamber spaces. A flexible diaphragm forms a compensation chamber on the bottom cover subject to atmospheric pressure. The chamber can communicate with the spaces within the liquid chamber through non-return means that block super-atmospheric flow to the compensating chamber. The porting and the communicating passage means between the spaces and the compensating chamber are formed integrally in the die-cast main body and/or the bottom cover, requiring no machining. Assembly is facilitated by bringing together the bottom cover, flexible diaphragm and non-return means as a sub-assembly.

Abstract: A device for forming panels of cast concrete having simulated mortar lines. The device rests above a casting bed on the beds rails. As the bed moves relative to the device, the movement is translated to a shuttle and press mechanism that descends into the uncured concrete, makes the impression, lifts and returns to the start. At this time the rear mortar line is now in position with the device to make a new forward line due to the indexing of the bed movement relative to the device.

Abstract: An improved slipform for use in a machine for casting hollow core concrete planks includes at least one angled baffle plate in the core material receiving ports so as to deflect the core material from directly impacting the lower concrete. This lessens the possibility of tears and holes in the lower layer caused by the core material.

Abstract: A device for lifting long, heavy concrete panels including clamping heads having diamond crystals bonded to the facing region to minimize slippage at the clamp head/concrete interface.

Abstract: The chairs include a lower chair portion for supporting multiple prestressing cables at the bottom of a plank and a narrow upper chair portion for supporting an upper prestressing cable located in the web between the hollow cores of the prestressed plank. The upper chair portion can be inserted into the strand receiving cups of the lower portion to form a structurally sound support for accurately placing the top and bottom reinforcing strands in the plank as it is cast.

Abstract: An insulated concrete panel utilizing interlocking sheets of insulation material sandwiched between two layers of concrete. The insulation material sheets are interlocked utilizing a symmetrical partial dovetail locking structure permitting subsequent sheets of insulating material to be interlocked with previously emplaced sheets without disturbance.

Abstract: A machine for casting concrete panels. The machine disclosed casts hollow core concrete panels in a single casting operation utilizing a slipform technique to fill cores with core material which can be dumped from the core after curing of the concrete has been accomplished. Vibration of the slipform during casting facilitates free flow of concrete around the slipform and core material extruded from slipforms. The slipfom has a closed front portion which is tapered to a reduced cross section. The machine utilizes a casting pallet employing improved side form cleaning apparatus. The machine also includes improved finishing screeds for applying decorative three-dimensional finishes on the top surface of cast panels.

Abstract: A method of manufacture in which the formation of unsightly stress cracks in sandwich-like panels of prestressed concrete are prevented by the formation of a "contraction joint" at selected locations in the panel's outer layer of concrete during its manufacture.

Abstract: A device for both lifting and dumping of core material from long hollow core concrete panels. The device utilizes a pair of retractable clamp members to engage the longitudinal groove in the side of the panel.

Abstract: A machine for casting concrete panels. The machine disclosed casts hollow core concrete panels in a single casting operation utilizing a slipform technique to fill cores with core material which can be dumped from the core after curing of the concrete has been accomplished. Vibration of the slipform during casting facilitates free flow of concrete around the slipform and core material extruded from slipforms. The slipform has a closed front portion which is tapered to a reduced cross section. The machine utilizes a casting pallet employing improved side form cleaning apparatus. The machine also includes improved finishing screeds for applying decorative three-dimensional finishes on the top surface of cast panels.

Abstract: A machine for removing uncured concrete from the top surface of a cast concrete slab to expose the aggregate therein to provide a decorative surface finish. The machine utilizes a pair of counter-rotating brushes to remove concrete which has been prevented from setting by use of a surface retarder, thereby exposing the aggregate to leave an attractive exposed aggregate finish. The counter-rotating brushes deposit the uncured concrete brushed from the surface of the slab onto a conveyor which carries the concrete waste to the edge of the slab for disposal.