Abstract: A plastic bag dispensing apparatus is provided which comprises a bag shield for facilitating the removal of only one bag at a time from the stack and for maintaining the billboard effect of the bags in the stack. The shield may be of various sizes and have openings of various shapes.

Abstract: Slip assemblies are provided for gripping drill pipe or other tubulars such that the load is distributed along the length of the dies of the slip segments rather than being concentrated at the lowermost dies within the slip segments. The load is distributed by the fact of using a load ring around the interior surface of each slip segment to allow the load ring to absorb part of the loading rather than have all of the load supported by the lowermost slip dies. In addition, resilient members are provided at the top surface of the uppermost die and also at the top surface of the die immediately underneath the load ring to better distribute the loading between the various slip dies and also to lessen the possibility of having gaps develop between the dies of the slip segments.

Abstract: An electrical system is disclosed which includes a supply voltage and electronic circuitry which requires an operational voltage that is less than the supply voltage. A thermoelectric heat pump is interposed between the supply voltage and the electronic circuitry to produce heating or cooling using the excess power which would otherwise be dissipated in a regulator. A voltage regulator is provided between the output of the thermoelectric heat pump and the electronic circuitry to provide the operational voltage to the electronic circuitry.

Abstract: A safety shielded, reusable trocar consisting of a trocar cannula subassembly, a safety shield control mechanism, and a separate obturator subassembly. The trocar cannula subassembly includes an outer cannula attached to a main housing having a central bore in which a spring biased, inner cannula is slidably and removably inserted, and an upper housing, removably secured to the main housing, having a central bore which is aligned longitudinally with the bore of the main housing and in which a seal is removably secured. The obturator subassembly includes an elongated obturator having a replaceable and rotatable knife, an elongated shaft, an arcuate shaped cap, and which extends through the upper housing, seal, main housing, inner cannula, and outer cannula. The safety shield control mechanism, located in the main housing and removably engaged with the inner cannula, allows for positive and easily verifiable engagement and disengagement of the inner cannula as a safety shield for the obturator knife.