[Background Art] Conventionally, in order to inject mortar when constructing or repairing structures or buildings, since manual tools such as shovels are mainly used, it is difficult to inject the mortar in the space between bricks.

Since the space between bricks is narrow because its size is about 8mm to 15mm, it is hard to inject mortar. Further, even when a mortar injection device is utilized, since tools for large buildings are used as they are, it is troublesome for a worker to inject mortar exactly to the desired place and to move to other places for next injection of mortar, and materials are wasted.

[Disclosure] [Technical Problem] Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a mortar injection device to accurately inject mortar using pneumatic pressure when constructing or repairing structures or buildings.

[Technical Solution] In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a mortar injection device using pneumatic pressure and including a long cylinder ; a mortar ejector coupled with the front end of the cylinder; and an air control unit having a valve mechanism coupled with the rear

side of the cylinder for controlling the introduction and discharge of compressed air and a piston repeatedly sliding in the cylinder, wherein a compressed air filling space is formed in the cylinder between the rear side of the cylinder and the piston, a mortar filling space formed between the piston and the mortar ejector, and the piston moves forward so that the mortar in the mortar filling space is ejected to the outside of the mortar injection device.

[Description of Drawings] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: Fig. 1 is a perspective view illustrating a mortar injection device according to the preferred embodiment of the present invention; Fig. 2 is an exploded perspective view of a compressed air control unit employed in the mortar injection device according to the preferred embodiment of the present invention; Fig. 3 is an exploded view of a piston of the mortar injection device according to the preferred embodiment of the present invention; Fig. 4 is a sectional view illustrating the mortar injection device according to the preferred embodiment of the present invention in a normal mode around a mechanism of the compressed air control unit; Fig. 5 is a sectional view illustrating the mortar injection device according to the preferred embodiment of the present invention in a compressed air supplying mode around the valve mechanism of the compressed air control unit; and Fig. 6 is a perspective view seen from the inside of a mortar ejector of the mortar injection device according to the preferred embodiment of the present invention.

[Best Mode] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a perspective view illustrating a mortar injection device according to the preferred embodiment of the present invention. The mortar injection device 1 according to the preferred embodiment of the present invent-ion includes an air control unit 2 and a mortar ejector 3 that are connected to the rear and front sides of a stainless steel cylinder 20, respectively. A region"A" in the cylinder 20 is a space, which is filled with mortar and a region"B"is a space, which is filled with compressed air.

Fig. 2 is an exploded perspective view illustrating an air control unit 2 by separating the same from the mortar injection device according to the preferred embodiment of the present invention, the air control unit 2 will be described in detail with reference to Figs. 1 and 2.

A piston 24 to press mortar is installed to the front end of a long penetrating rod 22 that is extended from the inside of the cylinder 20 to a grip 28, provided for easy gripping, and a ring-shaped cylindrical seal 26 that is tightened to the rear side of the cylinder 20 to seal the cylinder 20 from the outside is installed at a position behind the piston 24.

If the front 24'of the piston 24 is formed in a cone shape, it is advantageous to push and eject the mortar out of the cylinder 20. Moreover, most of the components of the mortar injection device according to the preferred embodiment of the present invention are made of stainless steel or aluminum alloy, but preferably, the piston 24 is made of urethane in order to prevent the piston 24 from rusting or corroding and to secure smooth sliding of the piston 24 within the cylinder 20. A urethane retainer 260 is inserted into and encloses the inner circumference of the seal 26 facing the cylinder 20 so as to firmly seal the rear side of the cylinder 20 from the outside. Reference

numeral 260 is assigned to a compressed air passing hole that communicates with an air introducing passage 500 and an air discharging passage 400 which are described later (See Fig. 4).

As shown in Fig. 1, the compressed air filling space B is formed between the piston 24 and the seal 26. When the compressed air passes through the compressed air passing hole 262 and is introduced into the compressed air filling space B, the piston 24 is pressed to move forward, as indicated by the arrow in the drawing, so that the mortar is ejected to the outside through the mortar ejector 3. When work is finished, the grip 28 is pulled to the rear side of the mortar injection device according to the preferred embodiment of the present invention to return to its original position.

Next, as devices to control the discharge of the compressed air the air control unit 2, there are a base 30, a trigger 36 pivotably suspended at the upper side of the base 30 by a hinge pin 36', a short cylindrical guide 30' extended between the upper end of the base 30 and the seal 26, and a discharging housing 32'coupled with the lower surface of the guide 30'.

A first valve 32 is installed between the trigger 36 and the discharging housing 32', and a second valve 34 is installed between the trigger 36 and the base 30. Opening and closing operation of the respective valves 32 and 34 by the trigger 36 will be described later. A spring 38 is disposed between the lower side of the trigger 36 and the front side of the base 30, and a supporting rod 38' penetrates the trigger 36 and is coupled with the trigger 36 by a bolt and is inserted into the front side of the spring 38. The spring 38 biases the trigger 36 to the left side, as seen in the drawing, and the trigger 36 receives resilient force of the spring 38 and is maintained at a normal mode (a stop mode) depicted in Figs. 1 and 2. In the stop mode of the trigger 36, the first valve 32 is open and the second valve 34 is closed. At that time, when the trigger 36 is moved rearward (to the right side as seeing

in the drawing) while overcoming the resilient force of the spring 38, the first valve 32 is closed and the second valve 34 is opened.

Moreover, a port 30''communicated with a compressor is installed at the lower end of the base 30.

Reference numeral 34''indicates an air adjustor to adjust the amount of introduced air.

The construction of the mortar ejector 3 will be described in detail with reference to Figs. 1 and 6.

The mortar ejector 3 includes a cylindrical fastener 42 to be fastened to the front end of the cylinder 20 and an injection port 40 provided at the front side of the fastener 42. An opening 40'is preferably formed at the front end of the injection port 40 in an approximately long and quadrangular shape for ejection of mortar. If the height of the opening 40'is set to about 7mm to 8mm, the mortar can be effectively injected into joints between general bricks having heights of 8mm to 15mm. Preferably, a urethane retainer 44 is attached to the inside of the fastener 42, and a slope 46 is formed at the inside of the retainer 44 toward the injection port 46, and a V-shaped introducing hole 48 is formed across the slope 46. Thus, when the piston 24 is moved by the compressed air, the mortar slides along the slope 46 and is discharged out through the introducing hole 48 and ejected out through the opening 40'of the injection port 40. At this time, the slope 46 functions to guide the mortar to be smoothly introduced into the introducing hole 48 without accumulation.

Fig. 3 is an exploded view of a piston of the mortar injection device according to the preferred embodiment of the present invention.

The piston 24 of the mortar injection device according to the preferred embodiment of the present invention is attached to the front end of the rod 22 and must push the mortar out to prevent the mortar from adhering to the inner surface of the piston 24. If the mortar sticks to and is hardened upon the inner surface of

the cylinder 20, the piston 24 receives considerable resistance and the mortar injection device according to the preferred embodiment of the present invention may malfunction. Thus, in order to push the mortar out clearly, as shown in the drawings, the piston 24 includes a first piston member 24-1 having a front side to closely contact the inner surface of the cylinder 20 and a gradually decreased diameter, a second piston member 24-2 having front and rear sides to closely contact the inner surface of the cylinder 20, and a third piston member 24-3 having a gradually increased diameter different from the first piston member 24-1 and contacting the inner surface of the cylinder 20. This triple divisional structure of the piston'24 is advantageous to completely push out the mortar and to smoothly move the piston 24.

The structure and operation of the valve mechanism of the mortar injection device according to the preferred embodiment of the present invention will be described in detail with reference to Figs. 4 and 5. Fig. 4 is a sectional view illustrating the mortar injection device according to the preferred embodiment of the present invention in a normal mode around the valve mechanism of the compressed air control unit, and Fig. 5 is a sectional view illustrating the mortar injection device according to the preferred embodiment of the present invention after driving the trigger, that is, in a compressed air supplying mode around the valve mechanism of the compressed air control unit.

As shown in Fig. 4, an air discharging passage 400 is formed from the discharging housing 32'to the compressed air passing hole 262. The first valve 32 includes a first valve rod 320 contacting the front surface of the trigger 36, a second valve rod 324 having a diameter less than the first valve rod 320, and a valve housing 326 integrally formed with the front side of the second valve rod 324.

The valve housing 326 is formed with a penetrating passage 328 that is aligned with the air discharging passage 400, so that the lower side of the discharging housing 32'

communicates with the compressed air passing hole 262. The rear side of the second valve rod 324 and the valve housing 326 are accommodated in a valve hall 32"formed across the front and rear sides of the discharging housing 32', and a spring 330 is disposed between the front end of the valve hall 32"and the front side of the valve housing 326 so as to press the valve housing 326 to the right side as seen in the drawings. Reference numeral 322 indicates a rod accommodator formed at the outside of the discharging housing 32'to accommodate the second valve rod 324. In this state, the first valve rod 320 is forced to move to the right side due to the spring 330, but the trigger 36 blocks the movement of the first valve rod 320.

Moreover, as shown in Fig. 4, an air introducing passage 500 is formed from the lower end of the port 30"to the compressed air passing hole 262 via the base 30 and the guide 30'. The second valve 34 includes a valve rod 340 contacting the rear side of the trigger 36 and a valve housing 342 integrally formed with the rear side of the valve rod 340. The rear side of the valve rod 340 and the valve housing 342 are accommodated in a valve hall 340' formed in front and rear direction of the base 30. A spring 346 is disposed between the rear side of the valve hall 340'and the rear side of the valve housing 342 so as to press the valve housing 342 to the left side as seen in the drawings. The valve housing 342 is formed with a penetrating passage 344. As shown in Fig. 4, the penetrating passage 344 is disposed left from the air introducing passage 500 as seen in the drawing, and the valve housing 342 closes the air introducing passage 500 so as to block the communication of the port 30"and the compressed air passing hole 262.

A rod of the air adjustor 34"penetrates the base 30 and its end contacts the rear side of the spring 346. When rotating the air adjustor 34"in the right direction, the spring 346 is pressed due to the forward movement of the rod of the air adjustor 34", so that the valve housing 342 is moved to the left side as seen in the drawing, but when

rotating the air adjustor 34"in the left direction, the valve housing 342 is moved to the right side as seen in the drawing due to the backward movement of the rod of the air adjustor 34".

Referring to Fig. 5 illustrating injection of the compressed air, when a worker moves the trigger 36 right as seeing in the drawing, the first valve rod 320 is moved right by the resilient force of the spring 330 of the first valve 32. The valve housing 326 closes the air discharging passage 400 so as to block the airflow, and the valve housing 342 pushed by the trigger 36 overcomes the resilient force of the spring 346 and moves along the valve hall 340'so that the penetrating passage 344 is aligned with the air introducing passage 500.

In this state, when the compressed air is supplied from the compressor through the port 30", the compressed air is introduced into the compressed air filling space B via the air introducing passage 500 and the compressed air passing hole 262 so that the piston 24 moves to eject the mortar as described above. Moreover, since the air discharging passage 400 is closed, the compressed air is not discharged out through the compressed air passing hole 262, that is, a sealing state is maintained.

In this state, as described above, the amount of air introduced can be adjusted by rotating the air adjustor 34" in a direction or in the other direction so as to adjust the opening area where the penetrating passage 344 communicates with the air introducing passage 500.

Therefore, during the injection of mortar, a worker can conveniently adjust the amount of mortar being ejected.

After a predetermined amount of mortar is injected, if the worker releases the trigger 36, the trigger 36, the first and second valves 32 and 34 return to the state shown in Fig. 4. When the worker pulls the grip 28, the air remaining in the compressed air filling space B flows backward and is discharged through the compressed air passing hole 262 and the air discharging passage 400 to the outside at the atmospheric pressure. Moreover, according

to the present invention, since the first valve 32 is opened and the second valve 34 is closed simultaneously with release of the trigger 36 and the compressed air filling space B communicates with the outside at the atmospheric pressure and its inner pressure is rapidly lowered, whereby the ejection of the mortar is immediately stopped simultaneously with the release of the trigger 36.

Since the conventional mortar injection device does not include the same structure as the valve mechanism of the mortar injection device according to the present invention, the mortar remaining in the conventional mortar injection device leaks therefrom even after the introduction of the compressed air is stopped.

As described above, it can be understood that since the valve mechanism of the mortar injection device according to the present invention is constructed as described above, a worker can repeatedly and rapidly perform the injection of mortar to the desired spot by simply manipulating.

The valve mechanism to control the introduction and discharge of the compressed air, which is employed in the mortar injection device according to the present invention, can employ the valve mechanism of the embodiments of the present invention and the conventional valve controlling mechanism, and a variety of changes and modifications of the structure and configuration of the valve mechanism, for example, a valve mechanism having a valve lever can be achieved.

[Industrial Applicability] As described above, the present invention provides a mortar injection device to accurately inject mortar using pneumatic pressure when constructing or repairing structures or buildings.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.