Toward achieving the above noted advantageous characteristics, we have provided a cylinder holder that mounts to the bottom portion of the "U" shaped, horizontal, patient torso supporting frame that is on each medical stretcher. This portion of the stretcher allows the patients torso to be elevated to various planes from horizontal to near vertical. The cylinder carrier is oriented so that its length it within the plane of the width of the stretcher with the mouth and, consequently, the regulator/stem portion of the oxygen cylinder orientated towards the left side of the stretcher (as an observer would be looking at the stretcher facing the head end). Our carrier apparatus utilizes adjustable straps which loop around the tubular framework of the patient's upper torso supporting frame of the stretcher and then attaches to a flexible, coated material bag that encloses the oxygen cylinder, continuing around both the bag and the cylinder to form a closed loop. This allows the oxygen cylinder to be suspended slightly below and in front of the "U" shaped torso supporting structure.

Artificial grass fields, on the other hand, require less maintenance and can be used much more intensively than natural grass fields. On artificial grass fields, however, the risk of sustaining injuries is considerably greater, due to the higher frictional resistance between the players' skin and the artificial grass fibres.

An inverter generation apparatus comprising means to obtain a reference duty ratio of predetermined switch elements of an inverter on-off driven to each of switch timings so as to have a desired waveform of an AC voltage obtained across load connection terminals, means to obtain correction coefficient for the duty ratio relative to a value reflecting a variation in an output voltage of a DC power circuit, means to obtain a real duty ratio by multiplying the reference duty ratio by the correction coefficient whereby the switch elements of the inverter are on-off driven in the real duty ratio so that the desired value of the AC voltage across the load connection terminals.

The retractable strap apparatus 10 may be secured to any desired article, such as a medical stretcher and the like, by a mounting bracket 48 in a well understood manner. A catch 50 present at the end of the strap 14 may be engaged to a buckle 52 in a conventional manner. The buckle 52 is mounted to a side of the desired article and, because of its standard nature, will not be described in detail. The buckle 52 may be of any size and shape necessary to receive and securely retain the catch 50. However, the buckle 52 shown in FIG. 1 has a shape that substantially matches the overall appearance of the spool container 18 to provide for a pleasing and uniform appearance.

Certainly, if the FET is employed in the output circuit of the portable generator, the supply of output current to the load can be cut off when excessive output current is detected to thereby protect the generator including the output circuit. However, if the over current detection is repeated in such a manner that while the engine which drives the generator continues operating, the load device connected to the output circuit of the generator is disconnected there from to release the current supply cut-off state, and then the load device is again connected to the output circuit to bring the latter into an overloaded state and hence again effect cutting-off of the current supply, such repeated disconnection and connection can impair the generator and the load device.

Toward achieving the above noted advantageous characteristics, we have provided a cylinder holder that mounts to the bottom portion of the "U" shaped, horizontal, patient torso supporting frame that is on each medical stretcher. This portion of the stretcher allows the patients torso to be elevated to various planes from horizontal to near vertical. The cylinder carrier is oriented so that its length it within the plane of the width of the stretcher with the mouth and, consequently, the regulator/stem portion of the oxygen cylinder orientated towards the left side of the stretcher (as an observer would be looking at the stretcher facing the head end). Our carrier apparatus utilizes adjustable straps which loop around the tubular framework of the patient's upper torso supporting frame of the stretcher and then attaches to a flexible, coated material bag that encloses the oxygen cylinder, continuing around both the bag and the cylinder to form a closed loop. This allows the oxygen cylinder to be suspended slightly below and in front of the "U" shaped torso supporting structure.