The connection method between steel supports and vertical and horizontal bars is the core guarantee for the overall stability of scaffolding. Different connection methods have differences in stress performance, installation efficiency, and applicable scenarios. The common connection methods can be divided into four categories: fastener connection, socket connection, bolt connection, and pin connection, as follows:
1、 Fastener type connection (the most commonly used traditional method)
The steel support (such as slant support and horizontal brace) is fastened to the upright and cross bar through metal fasteners, which is the symbolic connection mode of fastener type steel pipe scaffold.
Type:
Rotating fastener: It is used to connect the bars that cross at any angle (such as slant support and upright, slant support and cross bar). The angle can be flexibly adjusted and fixed by bolts.
Right angle fastener: mainly used to connect vertically intersecting members (such as horizontal bars and vertical bars), fixed at a 90 ° right angle to ensure rigid connection between horizontal and vertical members.
Docking clip: used for extending the docking of two steel pipes in the same direction (such as vertical pole extension, horizontal bar extension), aligning and clamping the ends of the two steel pipes through the clip.
characteristic:
Advantages: Strong universality, suitable for various specifications of steel pipes (such as φ 48.3mm), flexible installation and disassembly, and low cost.
Disadvantages: Relying on manual tightening of bolts, uneven pre tightening force can easily lead to loose nodes; After long-term use, fasteners are prone to rusting and slipping, and regular inspections are necessary.
Applicable scenarios: conventional scenarios such as floor standing scaffolding and full house scaffolding, especially suitable for projects with medium loads and heights ≤ 50m.
2、 Plug and socket connection (modular and efficient connection)
By directly plugging the plug at the end of the rod into the socket, and fixing it with self-locking or auxiliary components, it is commonly used in new scaffolding systems such as bowl buckle and plate buckle.
Type:
Bowl buckle connection: the bowl socket plate is welded on the vertical pole, and the plug is welded on the ends of the cross bar and the slant support. After the plug is inserted into the bowl buckle, it is rotated and locked with the upper bowl buckle to form a rigid node.
Disc buckle connection: the vertical pole is welded with perforated discs at a certain interval, and the ends of the cross bar and slant support are welded with connectors with pins. The pins are inserted into the disc holes and then locked by knocking, which can realize multi angle connection (0 °, 45 °, 90 °, etc.).
Slot type connection: A long rectangular slot is opened on the side of the upright pole, and a plug with a protruding block is welded at the end of the horizontal bar. After the plug is inserted into the slot, it is fixed by a spring or wedge block, suitable for lightweight scaffolding.
characteristic:
Advantages: Strong node rigidity and high bearing capacity (the shear strength of buckle type nodes is more than three times that of fastener type nodes); Fast installation speed, no need to tighten bolts, suitable for standardized construction.
Disadvantages: Fixed rod specifications, poor universality; The initial investment cost is high (requiring customized processing of poles with nodes).
Applicable scenarios: High stability projects such as tall formwork supports, heavy scaffolding, large-span structures, and projects that require rapid installation.
3、 Bolt connection (high-strength rigid connection)
The use of bolts and nuts to fasten the steel support to the connecting parts (such as flanges and connecting plates) of the uprights and crossbars is a rigid connection method.
Type:
Flange connection: Weld flanges (steel plates with bolt holes) at the ends of steel supports, uprights, and crossbars, and fix the flanges together with multiple bolts. It is suitable for heavy-duty steel supports (such as steel pipes or section steel supports with a diameter of over 100mm).
Connecting plate connection: small connecting plates shall be welded at the side of the bar, and the support shall be fixed with the connecting plate of the upright/cross bar through bolts. It is commonly used for the lateral connection of slant support and upright.
characteristic:
Advantages: High connection strength, no slippage of nodes, suitable for scenarios with heavy loads and strong vibrations (such as steel structure hoisting scaffolding).
Disadvantages: time-consuming installation and disassembly, requiring tool assistance; Bolts are prone to rusting or loosening due to vibration, and need to be tightened regularly.
Applicable scenarios: heavy support systems, steel cantilever beams and upright connections of suspended scaffolding, main support nodes of tall formwork supports, etc.
4、 Pin/wedge connection (quick positioning connection)
The rapid fixation of members by inserting pins or wedges, relying on friction or mechanical self-locking to transmit loads, is commonly used in lightweight or temporary scaffolding.
Type:
Pin connection: Reserve pin holes at the connection between the vertical pole and the horizontal pole. During installation, pass the pin through the hole and install a barbed or split pin at the end of the pin to prevent it from falling off. It is suitable for small load scenarios.
Wedge block connection: Wedge plugs are welded at the ends of the horizontal bars, and wedge-shaped slots are provided on the vertical bars. After inserting the plug, it is tightened with a wedge block and fixed using the principle of wedge self-locking. When disassembling, the wedge block can be tapped to release it.
characteristic:
Advantages: Extremely fast installation speed, no need for tools, suitable for emergency or temporary setup (such as emergency scaffolding).
Disadvantages: The node has low bearing capacity, poor pull-out performance, and is prone to loosening due to vibration during long-term use.
Applicable scenarios: Light scaffolding, temporary operating platforms, indoor decoration scaffolding and other scenarios with low loads.
