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A **composite door multipoint locking system** is an advanced security mechanism designed to
lock the door at multiple points along the frame, providing enhanced protection, durability, and
resistance against forced entry. The inclusion of **galvanized steel** components, such as the
**parrot hook locks**, adds to the strength and security of the door. Here’s an in-depth
breakdown of the different aspects of a composite door’s multipoint locking system, with a focus
on the materials and mechanics involved.
### **Key Components of a Multipoint Locking System**
1. **Central Deadbolt**
- The **central deadbolt** is the primary locking point located in the middle of the door, behind
the handle. It is a thick, robust piece of metal (often steel) that extends into the door frame when
the door is locked. This provides a strong central lock, similar to a standard deadbolt used in
single-point locking systems. However, in a multipoint system, the deadbolt is only one of
several locking mechanisms.
2. **Parrot Hook Locks**
- The **parrot hook locks** are one of the most critical security features of a composite door’s
multipoint locking system. These hooks are named for their curved, beak-like shape, which
engages deeply into the metal keeps (reinforced strike plates) in the door frame when locked.
Unlike simple bolt mechanisms, parrot hook locks **"grab"** the door frame from the inside,
making it significantly harder for intruders to force the composite door open.
- The hooks are usually positioned at the top and bottom of the door, though they can also be
located at additional points depending on the system's configuration.
**Galvanized Steel in Parrot Hook Locks:**
- **Material:** Parrot hooks are typically made from **galvanized steel**, which is steel coated
in a protective layer of **zinc**. This process, known as galvanization, enhances the steel’s
resistance to **corrosion** and **rust**. Since doors are exposed to the elements (rain, humidity,
etc.), galvanizing the steel is essential to ensure that the locking mechanisms don’t deteriorate
over time, especially in the often humid environment between the door and frame.
- **Strength:** The **high tensile strength** of galvanized steel ensures that the hooks are
durable enough to resist bending or breaking when force is applied. This makes them more
secure than standard bolts or pins, as they provide a more substantial barrier against forced
entry attempts like prying or kicking.
- **Mechanism:** When the door handle is lifted, the parrot hooks are engaged. As they rotate
into the door frame, their curved shape "hooks" securely into the metal keep within the frame,
ensuring a **deep, interlocking engagement** that’s difficult to disengage without unlocking the
mechanism properly.
3. **Roller Cams or Compression Rollers**
- Many multipoint locking systems also feature **roller cams** or **compression rollers**,
which are additional locking points positioned between the parrot hook locks. These cams are
round, rotating elements that press firmly into the door frame when the handle is lifted. Their

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purpose is to provide a tight seal, improving the door’s weatherproofing, reducing draughts, and
enhancing sound insulation. They also contribute to the door’s overall security by increasing the
number of points where the door is held tightly in place.
4. **Latch**
- The **latch** is part of the mechanism that keeps the composite door closed when it’s not
fully locked. It engages automatically when the door is shut and can be disengaged simply by
pressing down on the handle. While not directly related to security (since it doesn’t lock), the
latch ensures the door remains closed and aligned with the locking points.
5. **Keeps (Strike Plates)**
- The **strike plates** or **keeps** are metal plates installed into the door frame, designed to
receive the bolts, hooks, and rollers when the door is locked. These are also typically made
from **reinforced steel** or **galvanized metal** to withstand the force of the locking
mechanisms. The strength and positioning of the strike plates are critical to the security of the
multipoint locking system, as they ensure the door remains tightly secured to the frame.
---
### **Mechanics of a Multipoint Locking System**
A multipoint locking system works by engaging multiple locking points simultaneously along the
length of the door when the handle is lifted or a key is turned. Here’s how it functions:
1. **Engagement**:
When you lift the door handle, several things happen at once:
- The **central deadbolt** extends into the strike plate in the door frame.
- The **parrot hook locks** rotate and hook into the keeps, securing the door tightly at the top
and bottom (and sometimes additional points along the door).
- Any **roller cams** or **compression rollers** are also pushed into place, pressing the door
firmly against the frame to create a weather-tight seal.
2. **Locking the System**:
After lifting the handle, turning the key engages the entire system. The key rotation moves the
central deadbolt, locks the handle in place, and ensures that all hooks, rollers, and deadbolts
are engaged and cannot be disengaged without the key. Once locked, the door is held tightly at
multiple points, making it extremely difficult to force open.
3. **Disengagement**:
To unlock the composite door, you reverse the process by turning the key, which retracts the
deadbolt and releases the hooks and rollers. Pushing down on the handle then disengages the
rest of the system, allowing the door to open.
---

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### **Advantages of the Multipoint Locking System in Composite Doors**
1. **Enhanced Security**
- **Multiple Locking Points:** The multiple hooks, bolts, and rollers provide several points of
contact along the door and frame. This makes it difficult for an intruder to use brute force to gain
entry, as the door is locked in multiple places rather than just at a single point.
- **Resilience to Attacks:** The combination of **galvanized steel parrot hooks** and
reinforced keeps means that the door can resist a variety of forced-entry methods, including
crowbars, kicking, or attempts to pry it open. The hooks engage deeply into the frame, making it
difficult to disengage them without a key.
- **Anti-Snap Cylinders**: Many multipoint systems also feature **anti-snap**, **anti-drill**,
and **anti-pick** cylinder designs, providing an additional layer of protection against lock-picking
or cylinder-snapping attacks.
2. **Weatherproofing and Insulation**
- The multiple locking points ensure the door is **pulled tightly against the frame**, creating an
effective seal. This not only increases security but also **prevents drafts** and **reduces noise**
from outside. The tight seal is particularly effective in composite doors, which are already
designed for energy efficiency.
- **Compression rollers** or cams provide an additional layer of weatherproofing by pressing
the door securely against the frame, improving thermal insulation and reducing energy loss.
3. **Durability and Long Lifespan**
- The use of **galvanized steel** for parrot hooks and other locking components ensures that
the multipoint system is **resistant to rust and corrosion**, even in harsh weather conditions.
This significantly extends the lifespan of the locking mechanism.
- The **robust materials** used in the locking system, including stainless steel or zinc-plated
components, ensure that the door remains reliable and secure over many years, with minimal
maintenance required.
4. **Improved Door Alignment**
- Since the composite door is secured at multiple points, it remains aligned and properly
sealed against the frame. This reduces the chances of warping or misalignment over time,
which can happen with single-point locks. A well-aligned door improves both security and
energy efficiency.
---
### **Conclusion**
A composite door's multipoint locking system, particularly with **galvanized steel parrot hooks**,
represents a highly secure, durable, and efficient locking mechanism. By engaging multiple
points along the door’s frame, it ensures enhanced protection against forced entry while
providing additional benefits such as improved insulation and weather resistance. The use of
**galvanized steel** for critical components like parrot hooks ensures that the system remains
strong, rust-resistant, and capable of withstanding long-term wear and tear, making it an ideal
choice for exterior doors.