Roll CageBasics

Contents

• Definition

• Roll Cage Structure (Overview)

• Description of Elements of Roll Cage

• Bracing Material

• Roll Cage Padding

• Pictures

Definition• Roll Cage is basically a frame that is used to protect the vehicle and provide the

base to vehicle’s strength.

• A roll cage is a specially engineered and constructed frame built in the passenger compartment of a vehicle to protect its occupants from being injured in an accident, particularly in the event of a roll-over. (Wikipedia)

• The purpose of the roll cage is to provide a minimal space surrounding the driver and to support all subsystems. The cage must be designed and fabricated to prevent any failure of the cage’s integrity. It should be large enough for accommodating hefty & tallest member participating in a team in driving position. (Rule Book)

Elements of Roll Cage

• 1. Primary Members

1. Rear Roll Hoop (RRH)2. Rear Hoop Overhead (RHO)3. Front Bracing Member (FBM)4.Lateral Cross Member (LCM)5. Front Lateral Cross Member (FLC)

• Secondary Members

1. Lateral Diagonal Bracing (LDB)2.Lower Frame Side (LFS)3.Side Impact Member (SIM)4. Under Seat Member (USM)5. Other cross members

Rear Roll Hoop (RRH)

• It is simply the back side of the vehicle. A panel behind the back of the driver.

• It support the rear side of the vehicle

• It is a vertical member. (20 degree allowance)

RRH Specifications

• The RRH is made up of a maximum of four sections: two LCs at highest and lowest points and two continuous, no break vertical members .

• This may be one continuous hoop/tube. The driver’s seat may not intrude into the plane(s) of the RRH.

• The RRH must be a minimum of 73.6 cm (29 in.) wide at 68.6 cm (27 in.) above the driver’s seat (H-point of driver).

Lateral Diagonal Bracing (LDB)

• Lateral diagonal bracing member is the member joining the 2 vertical members of the RRH (Rear Roll Hoop)

LDB Specifications

• The top and bottom intersections of the LDB members and the RRH vertical members shall begin at a point along the vertical portion of the RRH within 12.7 cm (5 in.) vertically of point BR or BL and extend diagonally to a point no farther than 12.7 cm (5 in.) above point AR or AL respectively.

• The angle between LDB members and RRH vertical members must be greater than or equal to 20 degree

Roll Hoop Overhead (RHO)

• It is basically the top member of the vehicle or the head of the vehicle.

• It forms the points CL and CR and should be less than 12’’ away from seat bottom when the seat back is in vertical position.

RHO Specifications

• Points CR and CL must be at least 30.5 cm (12 in.) forward of a point in the vehicle’s elevation view, defined by the intersection of the RHO member and a vertical line rising from the after end of the seat bottom.

• This point on the seat is defined by the seat bottom intersection with a 10.1 cm (4 in.) radius circle which touches the seat bottom and the seat back.

Lower Frame Side members (LFS)

• These are the members or the edges that support the bottom of the vehicle and are connected to RRH through points AL and AR.

• It basically connects the front and back of the vehicle from the lower side of the vehicle.

Side Impact Members (SIM)

• The two Side Impact Members define a horizontal mid-plane within the roll cage. These members are joined to the RRH at points S and extend horizontally to points SF forward of the driver’s toes

SIM Specifications

• The SIM must be between 20.3 cm (8 in.) and 35.6 cm (14 in.) (as measured vertically) above the area of the seat in contact with the driver

Under Seat Member (USM)

• The two LFS members must be joined by the Under Seat Members. The USM must pass directly below the driver.

Front Bracing members (FBM)

• Front bracing member is the front part or face of the roll cage.

• Front bracing members (continuous, with no break) must join RHO, SIM and LFS

• The FBM must be continuous tubes.

• The angle between the FBMUP and the vertical must be less than or equal to 45 degrees.

Lateral Space Dimensions (acc. Rule Book)

• The minimum space is based on clearance between the driver and straight edge applied to any two points on the roll cage:

1. The driver’s helmet to be 152 mm (6 in.) clearance to the top of roll cage. 2. The driver’s shoulders, torso, hips, thighs, knees, arms elbows, and hands, shall have a minimum of 76 mm (3 in.) of clearance from the envelope created by the structure of the car.

Materials for Roll Cage Tubing

• Mild Steel Tubing: Choice for Race CarsReason: Its durability and its lightweight

• Chromoly Steel Tubing: More stronger than mild steel tube.All welds must be heat treated

Material to be used in BAJA SAE

• Circular steel tubing with an outside diameter of 25mm (1 in.) and a wall thickness of 3 mm (0.120 in.) and a carbon content of at least 0.18%.

Roll Cage Padding

• Any portion of the roll cage, which would be contacted by the driver, must be covered by a resilient foam material such as Polyethylene® (pipe insulation) with a minimum thickness of 1.2 cm (0.5 in.).

• All sharp edges which might endanger the driver, crew, officials and safety staff must be eliminated by shielding and/or padding.

Here are some images of ROLL CAGE……

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