JPH0228022Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a demolding device for formwork such as precast concrete members.

When demolding a formwork such as a precast concrete member, it is first necessary to separate the cast concrete surface from the formwork. The delaminated formwork can be easily removed from the concrete. When demolding formwork for large concrete components, this peeling is not easy, and conventional methods of peeling include driving a wedge between the concrete and formwork, or applying impact to the formwork with a sledgehammer, etc. There are several methods that are compatible with these methods, including the method of peeling off the formwork using a screw jack or hydraulic jack, and the method of pulling the formwork outward using a lever block or other traction device. Various devices have been devised to do this.

Methods using wedges or sledgehammers have disadvantages such as unnecessary deformation of the formwork, are labor intensive, and are inefficient, while methods using jacks or traction devices require large-scale equipment, It has drawbacks such as being cumbersome to operate.

The object of the present invention is to provide a demolding device that eliminates the above-mentioned drawbacks and allows a mold to be peeled off from a concrete surface using a simple device.

Embodiments of the present invention will be described below with reference to the drawings.

Figures 1 and 2 are a front view and a side view of an embodiment of the device of the present invention, Figure 3 is a partial sectional view of a concrete girder showing the embodiment attached to a formwork, and Figure 4 is a diagram showing the implementation of the device. It is an example acting force diagram.

The present invention is a demolding device that is attached to the upper edge flange 6 of a formwork 5 for concrete 4 and that allows the formwork to be easily peeled off from the concrete surface by lifting the crank upward with a crane hook or the like.

The present invention consists of an alligator-shaped hardware, a locking rod that locks onto the inner surface of the formwork, a push rod that applies a reaction force to the concrete surface, and an L-shaped crank.

In the present invention, two parallel flat plates 1 and 2 are connected by a connecting member 3 orthogonal thereto to form a crocodile-shaped hardware, and this crocodile-shaped metal fitting is configured so that it can be attached to a horizontal flange 6 on the upper edge of a formwork 5 of concrete 4. do. Near the tip of the flat plate 1 on the upper edge of the alligator-shaped hardware, a locking rod 7 is inserted into the 2
holes 8 are bored. After the locking rod 7 has its alligator mouth attached to the flange 6 on the upper edge of the formwork, it is inserted into the hole 8 and locked inside the formwork, and is pulled in a direction to separate the formwork 5 from the concrete 4 as described later. It has a tensile effect.

A bracket 9 is suspended from the lower surface of the flat plate 2 below the alligator opening, and a push rod 10 that penetrates the weir plate of the formwork 5 and comes into contact with the concrete surface is attached to the sleeve 1 at its lower end.
1 to be slidably held. This push rod 10 serves to support the concrete surface against the reaction force of the force that causes the formwork to peel off.

A hole through which a pin 12 is inserted is bored at the rear of the alligator mouth of the connecting member 3 constituting the alligator mouth hardware, and an L-shaped crank 13 is supported by the pin.

The L-shaped crank 13 has two L-shaped cranks sandwiching the connecting member 3.
It is made up of shaped plates connected by a distance piece 14, and consists of a vertical part and a horizontal part. The vertical part is supported at its middle by a pin 12, and its lower end 15 abuts against the head of the push rod 10. The horizontal part is installed horizontally from the top of the vertical part above the Waniguchi,
An engagement portion 16 with a lifting fitting 17 is provided at its tip.

The L-shaped crank 13 is rotatable around the pin 12.

FIG. 3 is a sectional view of a precast concrete girder showing an example of the device of the present invention attached to the girder. The demolding device of the present invention uses a hoisting fitting 17, such as a lever block, etc., which is suspended from a formwork hoisting fitting of a formwork hoisting crane (not shown).
The formwork 5 is peeled off from the concrete 4 by engaging the engaging portion 16 and pulling it upward.

FIG. 4 is an acting force diagram of the device of the present invention. L
The mold crank 13 is supported by a pin 12 on the alligator-shaped metal fitting, and an engaging part 16 with a lifting fitting 17 at the end of the horizontal part
Since it is pulled upward, an upward force P acts here. At this time, the lower end 15 of the vertical portion of the L-shaped crank is in contact with the head of the push rod 10, and the other end of the push rod 10 is in contact with the concrete 4.

If the line connecting both ends 15 and 16 of the L-shaped crank 13 is divided into n:1 by a perpendicular line passing through the pin 12, as shown in FIG. When an upward force P is applied, the vertical lower end 15 of the L-shaped crank 13 pushes the push rod 10 with a horizontal force nPtanθ, receives a reaction force of the same magnitude from the concrete, and a horizontal force of (n+1)Ptanθ is applied to the pin 12. act. This horizontal force is transmitted from the pin 12 to the connecting member 13 and the edge 1 of the alligator-shaped hardware to the locking rod 7, and the locking rod 7 uses this horizontal force to pull the formwork 5 horizontally. 5 easily peels off from the concrete surface.

The demolding device of the present invention does not require a reaction force support device because the reaction force is supported by the concrete surface as described above. Therefore, the overall structure is extremely simple and lightweight, making it easy to handle. Furthermore, an existing crane can be used, and no special traction equipment, jacks, or other actuator power is required. Jacks and other hydraulic mechanisms, electrical components, etc. must be removed when steam curing concrete, but the device of this invention does not require removal of the device or other special consideration when steam curing concrete. .

In addition, with respect to the upward force P, the horizontal force in the formwork peeling direction is magnified by the lever principle as shown in Figure 4, so by applying a small upward force P, the mold The frame can be easily removed from the concrete surface.

As mentioned above, the demolding device of the present invention has excellent effects such as being simple, compact, lightweight, high performance, and labor-saving.For example, it can be used for side formwork of precast prestressed concrete girders with a span of 20 m. By installing two units of this device at appropriate positions, the formwork can be easily peeled off from the concrete surface.

[Brief explanation of the drawing]

Fig. 1 is a front view of the embodiment of the present invention, showing the state in which it is attached to a formwork, Fig. 2 is a side view of the embodiment (viewed along arrow A-A in Fig. 1), and Fig. 3 is the embodiment of the invention. FIG. 4 is a cross-sectional view of the concrete girder showing the state in which the concrete girder is attached to the formwork of the girder, and FIG. 4 is an acting force diagram of the example. 1, 2... Parallel flat plate of alligator-shaped hardware, 3... Connecting member, 4... Concrete, 5... Formwork, 6...
Formwork upper edge flange, 7...locking rod, 8...through hole,
9... Bracket, 10... Push rod, 11... Sleeve, 12... Pin, 13... L-type crank, 1
4... Distance piece, 15... Vertical lower end, 16... Engaging portion, 17... Lifting fitting, 18...
...Futsuku.

Claims (1)

[Scope of utility model registration request] An alligator-shaped metal fitting that connects two parallel flat plates with a connecting member perpendicular to the two and can be attached to a horizontal flange on the upper edge of a concrete formwork, and a metal fitting that is inserted into a through hole near the tip of the upper edge of the alligator-mouth and attached to the inner surface of the formwork. a locking rod to lock;
It consists of a push rod that is slidably held at the lower end of a bracket suspended from the lower surface of the alligator mouth and that penetrates the formwork weir plate and comes into contact with the concrete, and an L-shaped crank that is held by a pin at the rear of the alligator mouth of the connecting member. , the L-shaped crank has a lower end of the vertical part abutting the push rod head, an intermediate part supported by the holding pin, and a lifting fitting at the tip of the horizontal part connected to the upper end of the vertical part and suspended horizontally above the alligator mouth. A formwork demolding device characterized in that it is provided with an engaging portion.