Concrete repairing agent injection plug

Abstract: A concrete repairing agent injection plug for injecting a concrete repairing agent into an injection groove (D) formed in a concrete wall to be repaired includes an elastic member (3) which is partly or fully inserted into the injection groove (D). First (1) and second (2) pressure plates sandwiched elastic member (3). The distance between the first (1) and second (2) pressure plates is changeable by a pressure mechanism (4, 5; 9; 10, 11). When the distance is reduced, the elastic member is compressed and is laterally expanded to bring into intimate contact with the walls of the injection groove (D) to thus close an open end portion of the groove (D). A concrete repairing agent injection pipe (6) is detachably insertable into through holes arranged in through the pressure members (1 and 2) and the elastic member (3). Upon completion of the sealing to the injection groove (D) by the elastic member (3), the repairing agent is injected into the groove (D) through the injection pipe (6). The injection plug and the injection groove (D) provide sufficient fluid tightness regardless of surface irregularities of the wall adjacent or around the injection groove so as to avoid leakage of the repairing agent during injection work.

Description: The present invention relates to an injection plug for injecting a repairing agent into a concrete wall. Degradation of concrete material of a concrete construction has been brought to attention. The degradation may caused through various reasons. The degradation of the concrete may incur separation of a rendering mortar formed over the concrete body therefrom. Such separation has lead to falling of the skin members of a building and a school, which caused fatal accidents for passersby. Accordingly, a proposal for a concrete wall repairing method is becoming a socially urgent matter. The present inventors have proposed a novel method for injecting a concrete repairing agent, in which double concrete cutters are used for forming a circular injection hole having an approximately constant width, and a concrete repairing agent injection plug which practices the method. These proposals have been described in co-pending application EP-A-0 469 717. The concrete repairing agent injection plug disclosed in the co-pending application is very effective when used to practice the above described injection method. However, the device has a packing surface which is depressed onto an outer wall surface portion surrounding the injection groove, and the packing is sealingly fixed at the portion for closing an open end of the injection groove. The device may incur the following disadvantages: When setting the injection plug over a coarse outer surface which is provided by spraying a mixture of coarse sands and a paint, for example the so called Tyrollean finish, it is necessary to enhance the fluid-tightness between the packing surface and the outer wall surface, at which the open end of the injection groove is positioned. To this effect, the outer surface must be subjected to machining with an electric disc grinder or the like so as to provide a smooth surface on the outer wall in order to provide intimate contact between the wall surface and the packing surface. If the injection plug is to be set on a locally irregular surface of the outer wall such as joint lines of tiles, it would be impossible to provide sufficient fluid tightness between the packing and the outer surface. Equally it would be rather difficult to fix the injection plug over a curved outer wall surface due to the configuration of the packing. Residual injection material may be adhered and fixed at an inner wall surface of the injection plug and the packing. Thus, it would be troublesome to remove the residual injection material therefrom. The residual material may be solidified at an injection nipple and closes a fluid passage defined in the injection plug device. The removal work may be troublesome. Particularly, if a check valve is provided within the fluid passage, it would be very difficult to remove the solidified residual material therefrom. DE-A-2642348 discloses a device for filling holes in flooring with a two component resin. The device comprises a tube for insertion into a bore hole in the floor which has a seal between the tube and the bore hole. According to this invention, a concrete repairing agent injection plug device for injecting a repairing agent into an injection groove formed in a concrete construction wall, the injection plug device comprises: an elastic member; a first pressure member positioned immediately above the elastic member; and, a pressure mechanism connected to the first pressure member to squash the elastic member, and is characterised in that the device further comprises: a second pressure member positioned immediately below the elastic member for sandwiching the elastic member between the first and second pressure members, the first and second pressure members and the elastic member being formed with a through hole arranged in line; and, a pipe member formed with a repairing agent injection passage and detachably insertable into the through hole for injecting the repairing agent into the injection groove, the pipe member having an outer portion protruding from the first pressure member and an inner end portion communicatable with the injection groove; wherein the elastic member is partly or fully insertable into the injection groove and, the pressure mechanism is connected to the first and second pressure members for reducing the distance between them to squash the elastic member to cause it to laterally expand and, in use, sealingly engage the sides of the injection groove. With the injection plug of the present invention, after a part of or the entire elastic member is inserted into the injection groove, the distance between the first and second pressure members which sandwich the elastic member therebetween is reduced by the pressure mechanism. Therefore, the elastic member is compressed and is laterally expanded. Because of the lateral expansion of the elastic member, the elastic member is brought into intimate contact with walls of the injection groove. Thus, the injection groove is sealed. Accordingly, sufficient fluid tightness can be obtained regardless of the condition of the wall surface portion adjacent the injection groove. Further, in the injection plug of the present invention, the concrete repairing agent injection pipe is detachably insertable into the through hole formed in the first and second pressure members and the elastic member. Therefore, when the injection work is finished, the injection pipe can be simply pulled out of the injection plug and scrapped. Accordingly, the intricate work involved in removing the residual repairing agent affixed at the internal portion of the injection plug can be avoided. Particular embodiments of the present invention will now be described with reference to the accompanying drawings, in which:- Fig. 1 is a cross-sectional side view showing a concrete repairing agent injection plug according to a first embodiment of the present invention; Fig. 2 is a cross-sectional side view showing the concrete repairing agent injection plug of the first embodiment set in conjunction with a circular groove formed in a concrete wall; Fig. 3 is a transverse cross-sectional view taken along a line III-III which extends through a central threaded rod shown in Fig. 2 for showing a structure of the concrete repairing agent injection plug of the first embodiment; Fig. 4 is a cross-sectional side view showing a concrete repairing agent injection plug according to a second embodiment set in conjunction with a circular groove formed in a concrete wall; Fig. 5 is a cross-sectional side view showing a concrete repairing agent injection plug according to a third embodiment set in conjunction with a circular groove formed in a concrete wall; Fig. 6 is a bottom view showing a second pressure member of the injection plug shown in Fig. 5; Fig. 7 is a cross-sectional side view showing a concrete repairing agent injection plug according to a fourth embodiment set in conjunction with a circular groove formed in a concrete wall; Fig. 8 is a transverse cross-sectional view taken along a line VIII-VIII which extends through a threaded rod of the injection plug shown in Fig. 7; Fig. 9 is a cross-sectional side view showing a concrete repairing agent injection plug according to a fifth embodiment set in conjunction with a circular groove formed in a concrete wall; and Fig. 10 is a transverse cross-sectional view taken along a line X-X shown in Fig. 9. A concrete repairing agent injection plug according to a first embodiment of the present invention will be described with reference to Figs. 1 through 3. In these Figures, there are shown a first pressure member 1, a second pressure member 2, an elastic member 3, a threaded rod 4, a nut 5, an injection pipe 6, an air discharge pipe 7, an outer mortar layer A, a concrete body layer B, a separation space layer C and a circular injection groove D. The first and second pressure members 1 and 2 are made of a material having high strength and rigidity such as a metal. The elastic member is made of an elastic material having a suitable elasticity such as a urethane rubber. Central portions of the first and second pressure members 1 and 2 are formed with through holes having inner diameters approximately equal to each other. Further, a thread is formed at the through hole of the second pressure member 2. A thread is formed at a tip end portion and an outer peripheral surface of the threaded rod 4. After the threaded portion of the threaded rod 4 is threadingly engaged with the thread of the second pressure member 2, a root portion of the rod 4 extends through the through holes formed at the central portions of the first pressure member 1 and the elastic member 3. Further, a nut 5 is threadingly engaged with a second threaded portion formed at an outer or an another end portion of the rod 4. Thus, the elastic member 3 is sandwiched between the first and second pressure members 1 and 2. The first and second pressure members 1 and 2 and the elastic member 3 are formed with a pair of through holes each extending in line at both sides of the central through holes. One of the through holes are inserted with a concrete repairing agent injection pipe 6, and the other through holes are inserted with the air discharge pipe 7. At a tip end portion of the injection pipe 6, a sleeved check valve mechanism which is similar to a valve used in a wheel of a bicycle is provided. That is, the tip end of the injection pipe 6 is closed by a blind member, and is formed with a plurality of radial small diameter bores 6a at a position behind the tip end portion, the bores being spaced away from one another by a circumferential distance. Further, a flexible elastic tube member or sleeve 6b is provided at a tip end portion of the pipe 6 to cover the small diameter bores 6a. On the other hand, at an outer end portion of the air discharge pipe 7, a flexible elastic tube 7a is covered. A top end portion of the tube 7 is nipped by a clip (not shown) so as to close an air discharge pipe defined in the pipe 7. The concrete repairing agent injection plug is used in the following manner. 1) The nut 5 is rotated in unfastening direction for moving the pressure members 1 and 2 away from each other. Thus, pressing force to the elastic member 3 is released. With this state, the air discharge pipe 7 and the injection pipe 4 are inserted into the right and left through holes, respectively. 2) As shown in Fig. 2, the injection plug is inserted into the circular injection groove D having an approximately constant width and circular depth, the groove being formed in the concrete wall by a conventional double blade type concrete cutter. The elastic member 3 is pressed into the injection groove D until an upper surface of the elastic member 3 becomes flash with the outer surface of the concrete wall. Incidentally, the concrete wall to be repaired includes the concrete body layer B and an outer mortar layer A covering the concrete body layer. The separation space layer C is provided therebetween which is formed by the degradation of the concrete body. The purpose of using the concrete repairing agent injection plug is to inject a concrete repairing agent such as a cement slurry and a mortar into the separation space layer C. 3) While the elastic member 3 of the injection plug is pressingly positioned in the injection groove D, the nut 5 is rotated in a fastening direction for moving the threaded rod 4, to thereby reduce the distance between the first and second pressure members 1 and 2. In accordance with the distance reduction, the elastic member 3 is compressed and is laterally expanded, so that the elastic member is brought into intimate contact with an inner surface of the injection groove D and outer peripheral surface of the injection pipe 6 and the air discharge pipe 7. Accordingly, high fluid sealability at the intimate contact portion can be provided. 4) The outer end portion of the injection pipe 6 is connected to an injection hose through a suitable connector for pressurizingly injecting the concrete repairing agent by a pump through the injection pipe 6. The injected concrete repairing agent is flowed into the injection groove D through fluid passages defined by the plurality of small diameter radial holes 6a formed at a position behind the tip end of the injection pipe 6 and by an inflation of the flexible tube 6b. In this case, air within the injection groove D and the separation space C can be discharged outside through the air discharge pipe 7. The injected repairing agent is filled in the injection groove D and the separation space layer C. When the injection is finished, the agent is leaked out of the outer end portion of the air discharge pipe 7. By this leakage, completion of injection work can be acknowledged. Then, the injection of the repairing agent is stopped, and an open end of the flexible tube 7a disposed over the outer end portion of the air discharge pipe 7 is closed by a suitable clip member so as to prevent the repairing agent from being further leaked. 5) If the concrete repairing agent injected by the process described in items (1) through (4), is solidified to some extent, the nut 5 is rotated in the unfastened direction, so that the elastic member 3 is laterally contracted because of its elasticity. Therefore, there is no intimate contact any more between the elastic member and the inner surface of the injection groove D. Subsequently, the injection plug is detached from the injection groove D to terminate the injection work of the concrete repairing agent. A concrete repairing agent injection plug according to a second embodiment of this invention will be described with reference to Fig. 4. In this Figure, like parts and components are designated by the same reference numerals as those shown in Figs. 1 through 3 to avoid duplicating description. In the concrete repairing agent injection plug of the second embodiment, the injection pipe 6 is positioned at a central portion of the plug, and two threaded rods 4a, 4b are disposed at both sides of the injection pipe 6. A concrete repairing agent injection plug according to a third embodiment of this invention will be described with reference to Figs. 5 and 6 wherein like parts and components are designated by the same reference numerals as those shown in Figs. 1 through 4 to avoid duplicating description. In the concrete repairing agent injection plug of the third embodiment, no check valve mechanism is provided in an injection pipe 60. Instead, the check valve mechanism is provided in the second pressure member 20. More specifically, at a central upper portion of the second pressure member 20, a large diameter recess 20a is formed for receiving a tip end portion of the injection pipe 60 which is inserted into the through holes formed in the first pressure member and the elastic member 3. On the other hand, at a central lower portion of the second pressure member 20, an accommodation pit 20b is formed for receiving therein a ball 60b. Further, a small diameter bore 60a is formed for communicating the large diameter recess 20a and the accommodation pit 20b. The ball 60b is urged toward the accommodation pit 20b by a leaf spring 60c so as to prevent the concrete repairing agent during injection from being reversely flowed. The leaf spring 60c is rotatably attached to the second pressure member 20 by an attachment bolt 60d. In case of removal work for removing the residual repairing agent, the leaf spring 60c is angularly rotated sidewardly as shown in Fig. 6 about an axis of the attachment bolt 60d so as to facilitate the detachment of the ball 60b from the accommodation pit 20b. Further, the injection pipe 60 is removed from the through hole. Here, the injection pipe 60 is a throwaway article, and can be prepared by cutting a widely available pipe into a predetermined length. Consequently, entire cost of the injection plug can be advantageously reduced. Fig. 7 is a cross-sectional side view showing a concrete repairing agent injection plug according to a fourth embodiment of this invention and an injection groove D in connection with the plug, and Fig. 8 is a lateral cross-sectional view taken along a line VIII-VIII extending through a center of a threaded rod shown in Fig. 7. In Figs. 7 and 8, like parts and components are designated by the same reference numerals as those shown in Figs. 1 through 6 to avoid duplicating description. In the concrete repairing agent injection plug of the fourth embodiment, the injection pipe 6 and the air discharge pipe 7 are positioned between the threaded rods 4a and 4b. Further, the compression to the elastic member 3 is not made by the fastening of the nut 5 as seen in the first through third embodiments, but can be made by an angular pivotal movement of a cammed lever 9. More specifically, an elongated member 8 is positioned between the nut 5 and the first pressure member 1. The elongated member has an upper horizontal bottom wall and two vertical side walls to provide a U-shape cross-section. A pair of support shafts 9a, 9a extend between the side walls, and one end of the cammed levers are pivotally connected to the elongated member 8 through the support shafts 9a. The pivot portion includes cam surfaces 9b whose radius is set larger than a normal distance between the upper bottom wall and the upper surface of the first pressure member 1. With the structure, while the cammed lever 9 is vertically oriented, the upper bottom wall of the elongated member 8 and the upper surface of the pressure member 1 provides the normal distance therebetween. In this case, the injection plug device is inserted and depressed into the injection groove D so as to provide contact of the elastic member 3 with the injection groove D. Then, the cammed lever 9 is pivotally moved in a direction about an axis of the support shaft 9a. Therefore, the elongated member 8 and the pressure member 1 are moved away from each other at a great force established by the camed surface 9b. Thus, the elastic member 3 interposed between the pressure members 1 and 2 is compressed at a greater force and is expanded laterally, so that the injection plug can be firmly fixed to the injection groove D. In this embodiment, compression degree to the elastic member 3 is controllable by the rotation of the nut 5. Fig. 9 is a cross-sectional side view showing a concrete repairing agent injection plug according to a fifth embodiment of this invention and an injection groove D in connection with the plug, and Fig. 10 is a cross-sectional view showing a toggle joint mechanism shown in Fig. 9. In Figs. 9 and 10, like parts and components are designated by the same reference numerals as those shown in Figs. 1 through 8 to avoid duplicating description. The plug device of the illustrated embodiment employs a compression mechanism using a toggle joint instead of the above described compression mechanism for compressing the elastic member 3. The toggle joint mechanism includes a L-shaped lever 10, a link 11 and shafts 10a, 10b and 10c. The L-shaped member 10 has an end portion pivotally supported to the vertical side walls of the elongated member 8 by means of a shaft 10b. The L-shaped lever 10 has an angled portion and an arm portion. The angled portion is pivotally connected to one end portion of a link 11 through the shaft 10a. The link 11 has another end portion pivotally connected to the first pressure member 1 by the shaft 10c. By pivotally moving the L-shaped lever 10 about the shaft 10b, the elongated member 8 and the pressure member 1 are moved away from each other at a great force. Therefore, the elastic member 3 interposed between the pressure members 1 and 2 are compressed at a great force to be expanded laterally, so that the injection plug can be firmly fixed to the injection groove D. In the above described embodiments, the air discharge pipe is provided. However, the air discharge pipe can be dispensed with. Further, in the illustrated embodiment, a length of the elastic member is slightly larger than a length of the open end of the circular injection groove D, so that both ends of the elastic member is bulged from the injection groove D. However, the length of the elastic member can be approximately equal to the open end length of the injection groove, so that the both ends of the elastic member can be completely inserted into the injection groove. Furthermore, in the above described embodiments, the check valve mechanism is provided at the injection pipe 6 or 60. However, the mechanism can be dispensed with. In the latter case, injection of the concrete repairing agent is suspended, and the outer end portion of the injection pipe disconnected from the injection hose should be closed by a suitable plug or lid member. As described above, in the concrete repairing agent injection plug device according to the present invention, after a part of or entire elastic member such as a rubber is inserted into the open end portion of the injection groove, the elastic member is laterally expanded by reducing the distance between the first and second pressure members which interpose therebetween the elastic member by means of the pressure mechanism. Therefore, the upper portion of the injection groove can be sealed by the laterally expanded elastic member. Consequently, sufficient fluid tightness can be obtained regardless of the wall surface condition adjacent the injection groove. Further, the injection plug of this invention is provided with the concrete repairing agent injection pipe insertable relative to the through holes arranged in line in the first and second pressure members and the elastic member. Therefore, upon completion of the injection work, the injection pipe can be simply detached from the injection plug for scrapping. Accordingly, obviated can be the intricate removal work for removing residual repairing agent solidified in the internal portion of the injection plug. The injection pipe 6(60) and the air discharge pipe 7 can be of cartridge type throwaway articles. In particular, in the third embodiment, ordinary rigid resin pipe can be used by cutting the same into a proper length. As a result, cost of the expendables can be greatly reduced, which leads to reduction in entire cost for the work. Moreover, since it is unnecessary to conduct removal work for removing the residual repairing agent, entire labor can be reduced.

Claims: A concrete repairing agent injection plug device for injecting a repairing agent into an injection groove (D) formed in a concrete construction wall, the injection plug device comprising: an elastic member (3); a first pressure member (1) positioned immediately above the elastic member (3); and, a pressure mechanism (4,5;9;10,11) connected to the first pressure member (1) to squash the elastic member (3), characterised in that the device further comprises: a second pressure member (2) positioned immediately below the elastic member (3) for sandwiching the elastic member (3) between the first (1) and second (2) pressure members, the first and second pressure members and the elastic member being formed with a through hole arranged in line; and, a pipe member (6) formed with a repairing agent injection passage and detachably insertable into the through hole for injecting the repairing agent into the injection groove (D), the pipe member (6) having an outer portion protruding from the first pressure member (1) and an inner end portion communicatable with the injection groove (D) ; wherein, the elastic member (3) is partly or fully insertable into the injection groove (D) and, the pressure mechanism (4, 5; 9; 10, 11) is connected to the first (1) and second (2) pressure members for reducing the distance between them to squash the elastic member (3) to cause it to laterally expand and, in use, sealingly engage the sides of the injection groove (D). An injection plug device according to claim 1, wherein a second through hole is formed in line in the first (1) and second (2) pressure members and the elastic member (3) interposed between them, , and the device further comprises an air discharge pipe (7) detachably insertable into the second through hole. An injection plug device according to claim 1 or 2, further comprising a check valve mechanism (6a, 6b; 6) positioned at an inner end portion of the pipe member (6). An injection plug device according to claim 3, wherein the check valve mechanism (6a, 6b) comprises: radial passage means (6a) provided at the inner end portion of the pipe member (6) and in communication with the injection passage (D) ; and, a tubular elastic member (6b) disposed to cover the radial passage means. An injection plug device according to claim 3, wherein the second pressure member (2) is formed with a first recessed portion (20a) at an upper side thereof for receiving the inner end portion of the pipe member (6), a second recessed portion (20b) at a lower side thereof, and a communication passage (60a) communicating the first (20a) and the second (20b) recessed portions, and wherein the check valve mechanism (60a, 60b, 60c; 60) comprises: a ball member (60b) positioned in the second recessed portion (20b); and, a biasing means (60c) having one end connected to the second pressure member (2) and the other end in contact with the ball member (60b) for urging the ball member (60b) in a direction to close the communication passage (60a). An injection plug device according to any one of the preceding claims, wherein the pressure mechanism comprises: a rod member (4) extending through the first (1) and second (2) pressure members and the elastic member (3), the rod member (4) having an inner end portion threadingly engaged with the second pressure member (2) and an outer end formed with a screw thread and projecting from the first pressure member (1); and, a nut member (5) threadingly engaged with the screw thread on the outer end of the rod member (4), the distance between the first (1) and the second (2) pressure members being reduced by screwing the nut member (5) further onto the rod member (4). An injection plug device according to claim 6, wherein a plurality of rod members (4) and nut members (5) are provided. An injection plug device according to any one of claims 1 to 5, wherein the pressure mechanism comprises: at least one rod member (4) extending through the first (1) and second (2) pressure members and the elastic member (3), the rod member (4) having an inner end portion threadingly engaged with the second pressure member (2) and an outer end formed with a screw thread and projecting from the first pressure member (1); a nut member (5) threadingly engaged with the screw thread on the outer end of the or each rod member (4); an elongate member (8) disposed between the or each nut member (5) and the first pressure member (1), the elongate member (8) having an upper wall and two vertical side walls to provide a U-shape cross section; and, at least one lever member (9) having one end portion pivotally supported by the vertical side walls of the elongate member (8) and being provided with a cam surface (9b) for decreasing the distance between the elongate member (8) and the first pressure member (1) upon pivotal movement of the lever member (9). An injection plug device according to any one of claims 1 to 5, wherein the pressure mechanism comprises: at least one rod member (4) extending through the first (1) and second (2) pressure members and the elastic member (3), the or each rod member (4) having an inner end portion threadingly engaged with the second pressure member (2) and an outer end formed with a screw thread and projecting from the first pressure member (1); a nut member (5) threadingly engaged with the screw thread on the outer end of the or each rod member (4); an elongate member (8) disposed between the or each nut member (5) and the first pressure member (1), the elongate member (8) having an upper wall and two vertical side walls to provide a U-shaped cross section; and, a toggle linkage formed by an L-shaped lever member (10) having one end portion pivotally supported by the vertical side walls of the elongate member (8) and having an intermediate angled portion and an arm portion and, a link member (11) having one end pivotally connected to the angled portion and another end pivotally connected to the first pressure member (1), the distance between the elongate member (8) and the first pressure member (1) being reduced by angular movement of the L-shaped lever member (10) to urge the first pressure member (1) toward the second pressure member (2).

Inventors: HAYASHI YUICHIRO, NAITO NOBORU, HAYASHI, YUICHIRO, NAITO, NOBORU
Applicants: NIHON MENTE KAIHATSU KABUSHIKI, NIHON MENTE KAIHATSU KABUSHIKI KAISHA
Application year: 1992
Main classification: E04G23
IPC codes: E04G23