WAC 296-155-965
Overhead protection for operators of
agricultural and industrial tractors. (1) General.
(a) Purpose. When overhead protection is provided on
wheel-type agricultural and industrial tractors, the overhead
protection shall be designed and installed according to the
requirements contained in this section. The provisions of WAC 296-155-955 for rubber-tired dozers and rubber-tired loaders
may be used in lieu of the standards contained in this
section. The purpose of the standard is to minimize the
possibility of operator injury resulting from overhead hazards
such as flying and falling objects, and at the same time to
minimize the possibility of operator injury from the cover
itself in the event of accidental upset.
(b) Applicability. This section applies to wheel-type
agricultural tractors used in construction work and to
wheel-type industrial tractors used in construction work. See
WAC 296-155-960 (1) and (3). In the case of machines to which
WAC 296-155-625 (relating to site clearing) also applies, the
overhead protection may be either the type of protection
provided in WAC 296-155-625 or the type of protection provided
by this section.
(2) Overhead protection. When overhead protection is
installed on wheel-type agricultural or industrial tractors
used in construction work, it shall meet the requirements of
this subsection. The overhead protection may be constructed
of a solid material. If grid or mesh is used, the largest
permissible opening shall be such that the maximum circle
which can be inscribed between the elements of the grid or
mesh is 1.5 in. (38 mm.) in diameter. The overhead protection
shall not be installed in such a way as to become a hazard in
the case of upset.
(3) Test procedures -- General.
(a) The requirements of WAC 296-155-960 (5), (6) and (7)
shall be met.
(b) Static and dynamic rear load application shall be
uniformly distributed along a maximum projected dimension of
27 in. (686 mm.) and a maximum area of 160 in.2 (1,032 cm.2)
normal direction of load application. The load shall be
applied to the upper extremity of the frame at the point which
is midway between the centerline of the seat and the inside of
the frame upright.
(c) The static and dynamic side load application shall be
uniformly distributed along a maximum projected dimension of
27 in. (686 mm.) and a maximum area of 160 in.2 (1,032 cm.2)
normal to the direction of load application. The direction of
load application is the same as in WAC 296-155-960 (8) and
(9). To simulate the characteristics of the structure during
an upset, the center of load application may be located from a
point 24 in. (610 mm.) (K) forward to 12 in. (305 mm.) (K)
forward to 12 in. (305 mm.) (L) rearward of the front of the
seat backrest to best utilize the structural strength. See
Figure V-25.
FIGURE V-25
Location for side load.
(4) Drop test procedures.
(a) The same frame shall be subjected to the drop test
following either the static or dynamic test.
(b) A solid steel sphere or material of equivalent
spherical dimension weighing 100 lb. (45.4 kg.) shall be
dropped once from a height 10 ft. (3,048 mm.) above the
overhead cover.
(c) The point of impact shall be on the overhead cover at
a point within the zone of protection as shown in Figure V-26,
which is furthest removed from major structural members.
FIGURE V-26
Zone of protection for drop test.
(5) Crush test procedure.
(a) The same frame shall be subjected to the crush test
following the drop test and static or dynamic test.
(b) The test load shall be applied as shown in Figure
V-27 with the seat positioned as specified in WAC 296-155-960
(5)(d). Loading cylinders shall be pivotally mounted at both
ends. Loads applied by each cylinder shall be equal within 2
percent, and the sum of the loads of the two cylinders shall
be two times the tractor weight as set forth in WAC 296-155-960 (6)(a). The maximum width of the beam illustrated
in Figure V-27 shall be 6 in. (152 mm.).
FIGURE V-27
Method of load application for crush test.
(6) Performance requirements.
(a) General. The performance requirements set forth in
WAC 296-155-960 (10)(b), (c) and (d) shall be met.
(b) Drop test performance requirements.
(i) Instantaneous deformation due to impact of the sphere
shall not enter the protected zone as illustrated in Figures
V-25, V-26, and V-28.
FIGURE V-28
Protected zone during crush and drop tests.
(ii) In addition to the dimensions set forth in WAC 296-155-960 (10)(a)(i) the following dimensions apply to
Figure V-28:
H
=
17.5 in. (444 mm.).
J
=
2 in. (50.8 mm.) measured from the outer
periphery of the steering wheel.
(c) Crush test performance requirements. The protected
zone as described in Figure V-28 must not be violated.
(7) Source of standard. This standard is derived from,
and restates, the portions of Society of Automotive Engineers
Standard J167 which pertain to overhead protection
requirements. The full title of the SAE standard is:
Protective Frame with Overhead Protection -- Test Procedures and
performance requirements. The SAE standard shall be resorted
to in the event that questions of interpretation arise. The
SAE standard appears in the 1971 SAE Handbook.
