AN EXPERIMENTAL AND ANALYTICAL INVESTIGATION OF MOWER-THROWN-OBJECT PHENOMENA. INTERIM REPORT

This report presents the results of an analytical and experimental investigation of mower-thrown-object phenomena. A mower-thrown-object analysis was conducted by developing a simple mathematical model to simulate the rotary action of the mower. A computer program that will compute the object velocities when provided with input for the mower and mowing conditions was also used to aid in the analysis of the mower-thrown-object phenomena. The experimental analysis was conducted to test the theoretical model by using a scale size mower model. High speed photography was used to determine the discharge characteristics of the mower-thrown object. The results show that (1) a higher value of the coefficient of restitution increased the velocity of the thrown object, (2) an increase in the blade rpm caused the object velocity to increase proportionally, (3) an increase in the inertia of the blade significantly increased the object velocities, (4) an increase in the distance of the point of contact of the object with the blade, from the center of rotation, increased the object velocities, and (5) the location of the pivot point played a major role in the object velocity after impact. The comparison of a straight bar blade and a pivoted bar blade (pivot located at the mid point) indicated that the pivoted blade construction resulted in approximately 28 percent smaller magnitudes for the object velocities.

• Supplemental Notes:
  • Research study title: Mower-Thrown-Object Accidents.
• Corporate Authors:

  University of Texas, Austin

  Center for Transportation Research, 3208 Red River Street
  Austin, TX  United States  78705

  Texas State Department of Highways & Public Transportation

  Transportation Planning Division, P.O. Box 5051
  Austin, TX  United States  78763

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • DaSilva, R E
  • Marshek, K M
  • Kannapan, S M
• Publication Date: 1986-8

Media Info

• Features: Appendices; Figures; References; Tables;
• Pagination: 116 p.

Subject/Index Terms

• TRT Terms: Blades (Machinery); Computer programs; High speed photography; Mathematical models; Mowing; Velocity
• Old TRIS Terms: Mower-thrown objects; Pivoted blade; Straight blade
• Subject Areas: Highways; Maintenance and Preservation; I61: Equipment and Maintenance Methods;

Filing Info

• Accession Number: 00475124
• Record Type: Publication
• Report/Paper Numbers: FHWA/TX-87/55+445-1, Res Rept 445-1, CTR 3-20-86-445-1
• Contract Numbers: Study 3-20-86-445
• Files: TRIS, USDOT, STATEDOT
• Created Date: Nov 30 1987 12:00AM