- Part Number:1928
- Part Number Title:Occup. Safety and Health Standards for Agriculture
- Subpart:1928 Subpart C
- Subpart Title:Roll-Over Protective Structures
- Standard Number:
- Title:Protective frames for wheel-type agricultural tractors -- test procedures and performance requirements.
- GPO Source:
The seat-reference point ("SRP") in Figure C-3 is that point where the vertical line that is tangent to the most forward point at the longitudinal seat centerline of the seat back, and the horizontal line that is tangent to the highest point of the seat cushion, intersect in the longitudinal seat section. The seat-reference point shall be determined with the seat unloaded and adjusted to the highest and most rearward position provided for seated operation of the tractor.
|Deflection of the frame, in. (mm)||±5 percent of the deflection measured.|
|Vertical weight, lb (kg)||±5 percent of the weight measured.|
|Force applied to the frame, pounds force (newtons).||±5 percent of the force measured.|
|Dimensions of the critical zone, in. (mm).||±0.5 in. (12.5 mm).|
W = Tractor weight (see 29 CFR 1928.51(a)) in lb (W' in kg);
Eis = Energy input to be absorbed during side loading in ft-lb (E'is in J [joules]);
Eis = 723 + 0.4 W (E'is = 100 + 0.12 W');
Eir = Energy input to be absorbed during rear loading in ft-lb (E'ir in J);
Eir = 0.47 W (E'ir = 0.14 W');
L = Static load, lbf [pounds force], (N) [newtons];
D = Deflection under L, in. (mm);
L-D = Static load-deflection diagram;
Lmax = Maximum observed static load;
Load Limit = Point on a continuous L-D curve where the observed static load is 0.8 Lmax on the down slope of the curve (see Figure C-5);
Eu = Strain energy absorbed by the frame in ft-lb (J); area under the L-D curve;
FER = Factor of energy ratio;
FERis = EuEis;
FERir = EuEir;
Pb = Maximum observed force in mounting connection under a static load, L lbf (N);
Pu = Ultimate force capacity of a mounting connection, lbf (N);
FSB = Design margin for a mounting connection; and
FSB = Pu/Pb
The test shall be conducted on a dry, firm soil bank. The soil in the impact area shall have an average cone index in the 0-in. to 6-in. (0-mm to 152-mm) layer of not less than 150. Cone index shall be determined according to American Society of Agricultural Engineers ("ASAE") recommendation ASAE R313.1-1971 ("Soil cone penetrometer"), as reconfirmed in 1975, which is incorporated by reference. The incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. The path of vehicle travel shall be 12º ± 2º to the top edge of the bank.
ASAE recommendation R313.1-1971, as reconfirmed in 1975, appears in the 1977 Agricultural Engineers Yearbook, or it may be examined at: Any OSHA Regional Office; the OSHA Docket Office, U.S. Department of Labor, 200 Constitution Avenue, NW., Room N-2625, Washington, DC 20210 (telephone: (202) 693-2350 (TTY number: (877) 889-5627)); or the National Archives and Records Administration ("NARA"). (For information on the availability of this material at NARA, telephone (202) 741-6030 or access the NARA Web site at http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.) Copies may be purchased from the American Society of Agricultural Engineers, 2950 Niles Road, St. Joseph, MI 49085.
The frame, overhead weather shield, fenders, or other parts in the operator area may be deformed in these tests, but shall not shatter or leave sharp edges exposed to the operator, or encroach on the dimensions shown in Figures C-2 and C-3, and specified as follows:
d = 2 in. (51 mm) inside of the frame upright to the vertical centerline of the seat;
e = 30 in. (762 mm) at the longitudinal centerline;
f = Not greater than 4 in. (102 mm) to the rear edge of the crossbar, measured forward of the seat-reference point ("SRP");
g = 24 in. (610 mm) minimum; and
m = Not greater than 12 in. (305 mm), measured from the seat-reference point to the forward edge of the crossbar.
10-mm x 10-mm (0.394-in. x 0.394-in.) specimen: 8.0 ft-lb (10.8 J) at -20 ºF (-30 ºC);
10-mm x 7.5-mm (0.394-in. x 0.296-in.) specimen: 7.0 ft-lb (9.5 J) at -20 ºF (-30 ºC);
10-mm x 5-mm (0.394-in. x 0.197-in.) specimen: 5.5 ft-lb (7.5 J) at -20 ºF (-30 ºC); or
10-mm x 2.5-mm (0.394-in. x 0.098-in.) specimen: 4.0 ft-lb (5.5 J) at -20 ºF (-30 ºC).
Specimens shall be longitudinal and taken from flat stock, tubular, or structural sections before forming or welding for use in the frame. Specimens from tubular or structural sections shall be taken from the middle of the side of greatest dimension, not to include welds.
[61 FR 9227, March 7, 1996; 70 FR 77004, Dec. 29, 2005]