2.The Effects of Handwheel Position on Torque Production
Capability of Operators.
Kathleen K. Wood, Lawrence J. H. Schulze, Jen-Gwo Chen, and Theodore G. Cleveland.
3.Effectiveness of Workplace Accommodations for a Corporate
Telephone Operator with a Full Left-Arm Prosthesis: A Case Study.
Lawrence J. H. Schulze, and Claudia G. Woods.
Journal of Occupational Rehabilitation, Vol.4 No. 2, 1994.
4.Effects of Pneumatic Screwdrivers and Workstations on
Inexperienced and Experienced Operators Performance.
Lawrence J. H. Schulze, Jerome J. Congleton, Rodger J. Koppa, and R. Dale Huchingson.
International Journal of Industrial Ergonomics. Vol 16. 1995.
5.Maximum Acceptable Weight of Asymmetrical Lifting and
Lowering of Postal Sacks.
Ashish G. Parikh, Lawrence J. H. Schulze, Jen-Gwo [Jacob] Chen and Theodore Cleveland.
International Journal of Industrial Ergonomics. Vol 19. 1997
6.Torque Production Using Hand Cranks in a Simulated Gear-Operated
Valve Opening Task.
Lawrence J. H. Schulze, Edward Stanton, Anupam Petel, and Maurizio Cheli.
International Journal of Occupaional Safety and Ergonomics. Vol 3 No 1-2. 1997.
7.Torque Production Using Handwheels of Different Size
During a Simulated Valve Operation Task .
Lawrence J. H. Schulze, David Goldstain, Anupam Patel, Edward Stanton, and James Woods
International Journal of Occupaional Safety and Ergonomics. Vol 3 No 3-4. 1997.
8.The Effects of the Valve Wheel Size, Operation Position
and In-Line Pressures on Required Torque for Gate Valves.
Sean C. Parks and Lawrence J. H. Schulze.
Process Safety Progress. Vol 17. No 4. Winter 1998.
9.An Application of Menu Design Principles to an Energy
David R. Latta, and Lawrence J. H. Schulze.
1.Four pneumatic screwdrivers, representing two different motor speeds and grip types, were used in both inexperienced (college student) and experienced male and female operators in a simulated and actual furniture assembly operation, respectively. All screwdrivers were used to set screws in furniture desk tops configured in three different orientations. The workstation/workpiece orientations were chosen to assess both ideal and non-ideal upperarm-forearm, wrist, shoulder and body postures assumed by operators during the assembly task. The results of this study indicate that less deviation of the upperarm-forearm and wrist was assumed by male operators. The female operators, necessarily disadvantaged by strength and stature, assumed postures representing greater body part abduction and deviation from neutral points. No differences were found between inexperienced and experienced operators.
2.A study was conducted to determine how the position of the handwheel affected the amount of torque applied by another operator. Data was gathered at a series of wheel heights and distances. Results indicate that the main effects of gender, wheel height, and wheel distance, and the interaction between gender and wheel distance were statistically significant. Although the main effect of wheel height was statistically significant, post hoc analysis showed that there were no practical differences in torque production among the 5 wheel heights used in this investigation. In addition, a strong correlation existed between torque production capability and handwheel height of 101.6 cm and weight of the male participants.
3.A corporate telephone operator and voice mail programmer was involved in a serious automobile accident resulting on left-arm amputation and through rehabilitation received a full left-arm prosthesis. Upon returning to work in her previous job capacity, some work activities and work area configurations were identified as problematic during task performance. Work methods and work area configuration were evaluated regarding their appropriateness for supporting return to work and long-term accommodation. Job activity analysis determined all reaches, clearances, and forces and their compliance with recommended criteria. A body part comfort/discomfort survey (BPCDS) was administered pre- and post- accommodation to elicit information regarding workplace problem areas and provide a measure to assess accommodation effectiveness. Workstation, support equipment, work area, seating, task assignments, and work methods were modified to more appropriately support operator task performance. Comparison of pre- and post- accommodation BPCDS indicated with the orthopedic prosthesis. This case study illustrates the use of the principles and techniques of industrial ergonomics to develop workplace accommodations. The area of ergonomics, medical ergonomics, is an example of the development of reasonable accommodations for physically challenged workers on the spirit of compliance with the American with Disabilities Act (ADA).
4.This study investigated the effects of pneumatic screwdriver characteristics and workpiece orientation on operator productivity. Operators used four pneumatic screwdrivers (two pistol and two straight grip) representing two different clutch types (positive and automatic air shut-off). The two grip types represented both fast (1700 RPM) and slow (1000 RPM) motor speeds. The pneumatic screwdrivers were used at each of the three different workstations representing different workpiece orientations (horizontal workpiece at a fixed height, horizontal workpiece with an adjustable height, and angled workpiece with adjustable height). In the first phase of the study, 18 university students (inexperienced operators) participated in a simulated furniture assembly operation. In the second phase, 16 experienced employees of a furniture manufacturing facility participated in an actual furniture assembly operation. The results of the study indicate that operations took longer to complete the required tasks and made more errors when the straight grip screwdrivers were used than when the pistol grip screwdrivers were used. These differences were more pronounced at the end of the task than at the beginning of the task. No strong performance differences were found among the three different workstations used.
5.The asymmetrical lifting of postal sacks without handles was simulated. Type-2 and Type-3 postal sacks (those typically used by the U.S. Postal Service) were loaded and unloaded from and to different cart conveyor levels. An adjustable table was used to simulate the different conveyor levels. There were six combinations of lift for each of twenty participants (ten male and ten female). A modified version of the psychophysical methodology was used to determine the maximum acceptable weight of lift. A significant difference was found between the weights lifted across cart heights. Specifically, the mean load lifted over the 96.5 cm (38.0 in) cart height was 15.337 kg (33.74 lb.) and was significantly greater than the average load lifted across the 20.40 cm (8.0 in) and the 104.20 cm (41.0 in) cart heights. However, this difference is not practically significantly different (mean difference = 1.44 kg). There was no significant difference (p>0.05) in the load lifted across table heights. A significant interaction occurred between cart height and conveyor height (p<0.05). This interaction indicated that as the vertical distance between the cart height and the conveyor height increased, the acceptable load handling capabilities of the participants decreased. The mean MAWL for Type-2 postal sacks (14.5 kg, 31.91 lb.) was similar to the mean weight lifted at the postal distribution center (16.4 kg, 36.0 lb.). The mean MAWL for Type-3 sacks (14.5 kg, 31.9 lbs.) was less than half of the mean weight lifted at the postal distribution center (24.6 kg, 54.1 lb.).
6.Hand cranks are used in a variety of industries to actuate valves in other gear-operated applications. In order to evaluate these types of operations and their compatibility with operator strength capabilities, a rotational dynamometer was used to measure torque production capability of operators using a hand crank at different heights and angles (with respect to the coronal plane). The tests were conducted for both clockwise and counterclockwise rotations using the dominant arm on each test participant. A total of 18 tests were completed by each of 5 male right-handed test participants. A 0 grades declination angle, counterclockwise operation, and both 45.65 cm and 60.96 cm heights were found to be associated with the greatest torque production capabilities.
7.Opening and closing valves in industrial facility often requires operators to use bars and wrenches as levers (cheaters) in order to overcome initial actuation forces. In order to determine more appropriate operational specifications, the maximum torque production capability was measured when 12 male participants used 4 different valve handwheels at 3 different height and 2 different angles (in relationship to the coronal plane). The results indicate that the participants produced significantly greater torque when the largest of the 4 wheels (40.6 cm diameter) was used than when the medium (22.9 cm), small (20.3 cm), and handled (17.8 cm) handwheels were used. Although the main effect of heights was found to be statistically significant, post-hoc analyses between the heights found them to be different. The results are applicable to all industries where handwheels are used and applicable to valve manufacturers for designing operational torque specifications below the valves found in this study.
8.Some of the hazards encountered by process plant operators involve the operation of in-line valves control, start, and to stop flow. Torque required to operate valves may vary according to valve wheel and size, in-line pressure, and valve flange position (open/closed). This study determined how valve wheel size, in-line pressure and valve position (open/closed) affect torque required to actuate a valve. Data were gathered with each combination of size, pressure and position for 336 valves in an operating petrochemical process facility. The results indicate that the main effects of the valve wheel size, the in-line pressure and the open/close valve position significantly affect operational torque requirements. In addition, the interaction between position and pressure was significant for the operational torque. The implication of these results is that operators are exposed to operational torque that exceed maximum acceptable capabilities that have been determined in previous studies.
9.The organization of a menu can significantly affect user response when selecting targets from that menu. Previous empirical studies have used laboratory tests to suggest menu design rules that can optimize user response. This study applied the design rules to a menu used for display selection on an Energy Management System. In such study, the total number of menu targets and the relationships among them is not variable, so some compromises must be made when applying the rules. This study produced a new menu that had measurable improvement in the user response time over the existing menu. Design rules regarding grouping of targets and methods of organization were successfully applied during the menu redesign.