High-Strength Automobile Luggage Rack with Arc-Section Connecting Pieces

The problem

Traditional automobile luggage racks typically consist of a simple crossbar plugged into fixed seats mounted on the vehicle roof. These connections rely heavily on bolts passing through small holes. When the rack carries heavy items—such as kayaks, rooftop tents, or large cargo boxes—the weight exerts significant torque on the crossbar ends. Because the contact area between the straight crossbar and the flat mounting seat is limited, this stress concentrates at the joint. Over time, or under sudden heavy loads, the crossbar can deform or bend near the connection point, compromising the structural integrity of the rack. Furthermore, assembling these multi-part systems often requires aligning multiple bolts simultaneously, which slows down production and makes DIY installation difficult for end-users.

The solution

This patent introduces a reinforced connection structure and a specialized assembly method.

1. Crossbar Design: The main crossbar features symmetric round holes for counter-bore bolts on its upper face. Crucially, the lower face contains a longitudinal “limit sliding groove.”
2. Connecting Pieces: Instead of simple plugs, the rack uses two connecting pieces per side that slide into this groove. Each piece comprises three distinct sections:
   • A horizontal section that slides within the limit groove.
   • A vertical section that extends downward to act as a support strut.
   • An arc-shaped section that connects the horizontal and vertical parts, fitting closely against the rounded end of the crossbar.
3. Load Distribution: The arc shape increases the contact area between the connector and the crossbar, distributing stress more evenly than a flat interface. When loaded, the vertical section presses against the vehicle roof, providing direct physical support that prevents the crossbar from bending downward.
4. Assembly Unit: To manufacture these racks efficiently, the patent details a mechanical assembly table. It uses a linkage system, gear sets, and a pressing assembly. Operators place the crossbar and seats in designated slots, then rotate a pressure rod downward. This action drives the components into alignment and locks them together, simplifying the assembly process significantly.

Who it is for

• Automotive Accessory Brands: Companies looking to differentiate their roof rack lines by marketing higher load capacities and resistance to deformation compared to standard aluminum extrusion racks.
• Manufacturers of Rooftop Cargo Systems: Businesses producing racks specifically for heavy outdoor gear like kayaks or camping tents, where structural failure poses safety risks.
• Aftermarket Parts Suppliers: Distributors who need durable replacement racks for SUVs and trucks, focusing on long-term reliability and ease of installation.
• OEM Contract Manufacturers: Factories seeking automated or semi-automated assembly solutions that reduce labor costs and assembly time through the patented quick-lock jig concept.

How it works

The main parts

The system relies on the interaction between the crossbar, the unique connectors, and the mounting feet.

Operating steps

1. Installation on Vehicle: The fixed seats (13) are bolted to the car roof rails. The crossbar (11) is positioned above them.
2. Sliding Connection: The connecting pieces (12) are inserted into the limit sliding groove of the crossbar. The arc-shaped section wraps around the end of the bar.
3. Bolting: Counter-bore bolts pass through the crossbar holes and thread into the horizontal section of the connecting piece, securing the joint.
4. Load Bearing: When cargo is placed on the bar, the vertical section of the connector transfers the load directly to the roof surface, while the arc section distributes stress along the bar’s length.
5. Factory Assembly: In production, the rack parts are placed on the assembly table (21). Rotating the pressure rod engages the linkage (22) and gears (25), pushing the connectors into the crossbar and seats simultaneously to snap them into final position before bolting.

Applications

Heavy-Duty Kayak Transport

Kayaks create uneven leverage on roof racks. The vertical support strut prevents the crossbar from bowing under the long, rigid hull, ensuring the kayak remains level and secure during transit.

Rooftop Tent Camping

Rooftop tents add significant static weight and dynamic wind load. The arc-shaped connectors distribute this stress over a larger area of the crossbar, reducing the risk of fatigue cracks at the mounting points.

Commercial Fleet Vehicles

Delivery vans and service trucks often carry ladders or pipes that extend beyond the rack edges. The robust connection design withstands the twisting forces generated by off-center loads better than standard plug-in racks.

Off-Road Adventure Gear

For vehicles used in rough terrain, vibrations can loosen standard joints. The tight fit provided by the sliding groove and rubber pads, combined with the structural bracing, maintains rigidity despite constant shaking.

Where it is less suitable

• Lightweight Urban Commuters: For users carrying only light backpacks or small boxes, the added complexity and weight of the reinforced connectors may be unnecessary compared to basic economy racks.
• Non-Standard Roof Rails: The fixed seats require specific bolt patterns compatible with common roof rail systems; custom-fit applications may need adapter plates not described in this patent.