Volume 9, numéro 1, january 1998

EN :

A radical, new innovation with regards to forestry machines is the designof a cab suspended from an arched column connected to a swiveling socket.The purpose of the design is to reduce the amount of skewed and twisted work postures, which are often frequent among operators of logging machines.The ability to sit straight is what most operators point out to be the most desirable feature of the self-leveling and swiveling cab. The low noise level is also appreciated, as is the ability to swivel the cab aroundon its vertical axis. The swiveling ability of the cab gives better visibility and also helps reduce the amount of head rotations. Furthermore, jarring motions and extreme swing due to uneven terrain are much less bothersome than in a conventional cab design. Vibration levels at the operator's seat in the self-leveling cab are equal to those measured in conventional rigidcabs. This new cab design provides comfort to the operator and improves the operator's ability to work at a sustained high efficiency. A follow-up study conducted over several years shows that the productivity of a harvester increased by 5 to 10% after a change from a rigid to a self-leveling andswiveling cab.

EN :

In the 18 months since the effective date of the US Occupational Safety and Health Administration's (OSHA) Logging Standard, 289 logging site inspections had been performed in the US by OSHA personnel. In West Virginia, 25 inspections found 170 violations ranging from incomplete first-aid kits and poor record keeping to hazardous felling areas. Four of these inspections were initiated by accidents that caused serious injury or fatality. The average proposed penalty per citation was $130.59. Approximately two-thirds of West Virginia loggers expressed misgivings about the OSHA standard. However, only 36% thought that they had a good knowledge of the OSHA logging regulations. Foresters and loggers in the US should be aware that OSHA regulations pertaining to timber harvesting operations are being enforced and, in some cases, may affect the way forests are harvested and managed.

EN :

The optimal model for a hydraulic crane compound scheme is discussed for four types of mobile logging machines: secondary transport truck or lorry, skidder (feller-skidder), forwarder, and harvester (feller-buncher).

EN :

An algorithm that combines tabu search principles with a simple improvement- swapping heuristic has been developed for allocating stands and cutting patterns to logging crews for a single time period. A limited set of market and operational constraints has been included. Individual crew productivity has also been taken into account. The algorithm has been implemented in Visual Basic. Tests have been carried out on up to 60 stands, 10 logging crews, and seven cutting patterns. The "best" solutions have usually been found within a few hundred iterations.

EN :

A time study of the cable extraction of thinnings in short corridors was carried out in the Neuberg an der Mürz forest area, Austria. Both the yarder and the choker-setter(s) were studied. Six options were compared. For the "standard" option the timber was felled, cut to length, and pre-bunched by the harvester on a 20-meter-wide corridor, and was yarded downhill. Two choker-setters were employed. The five variations included: (1) "larger" bundles, (2) in-creased lateral hauling distance, (3) one choker-setter, (4) the harvester cutting-to-stem length and the timber yarded uphill with only one choker setter, and (5) trees in a 30-meter-wide corridor felled and bucked by motor-manual methods. The harvester used was a Skogsjan 687 XL with a 601 head; the medium-sized yarder was a Syncrofalke with a Sherpa U3 carriage.

The time study results showed that the corridors felled and cut to length by the harvester, in comparison to the motor-manually cut corridor, provided a significant improvement in the cable extraction cycle times: 3.7 min compared to 4.6 min. Additionally, an average turn volume increase of 26% was achieved by the improved presentation of the timber. A 20-meter lateral-hauling distance increased the cycle time by only 7%. The use of one choker-setter increased the delay-free cycle time by just 10%, however it significantly decreased the work-related waiting time for the choker-setter to just 5%. Uphill stem extraction using one choker-setter had the same cycle time as the downhill cut-to-length extraction using two choker-setters, although a 5% greater average turn volume was recorded.

EN :

This study is part of the ongoing national Bioenergy Research Programme in Finland. The study looked into the quality of chips made of logging residues composed predominantly of spruce wood. In addition, the productivity of the Evolution 910R chipper, the MOHA chipper truck, and the Morbark 1200 tub grinder was studied.

The three machines studied were capable of producing acceptable chips for heat generation plants. The particle-size distribution was good in all cases and the proportion of large particles and the fine fraction was small. The ash content of the chips was low due to carefulness in the handling of logging residues. The moisture content was typical for logging residues stored at the logging site for some months. The machine productivity values obtained were as follows: Evolution = 65 m3 loose/E15-h, MOHA = 23 m3 loose/E15-h, and Morbark = 5060 m3 loose/E15-h. These results are preliminary; a follow-up study is needed for more reliable results to be obtained concerning the productivities.

EN :

Despite a reduction in the workplace injury rate for most industries in Canada, the number of compensation claims for the Canadian Forest Industry is not declining at a comparable rate. While mechanisation, particularly of tree harvesting operations, has improved injury rates in the last 5 to 7 years, the forest industry, along with similar labour-intensive industries such as mining, construction, and agriculture, continue to have unacceptable health and safety records.

This review of ergonomics codes of practice focuses on the issue of implementation, as perceived by the three major stakeholders, management, employees and their unions, and government. Barriers to implementation and successful programs are discussed, as is the use of Benefit/Cost analysis as one measure of success. Three examples of successful ergonomic interventions in Canadian forestry, manufacturing, and healthcare are detailed to illustrate the effective use of Benefit/Cost analysis as a measurement tool, and as the potential path to the implementation of universal codes of practice.