Joint cutting device and joint cutting method

Abstract

To reduce labor of workers and make positioning easier in work for cutting joints in concrete.SOLUTION: A joint cutting device 100 has a base unit 120 that is rectangular and long in plan view, and a blade unit 140 that has a blade 142 for cutting joints in concrete. A slit 122A through which the blade 142 of the blade unit 140 can be inserted is formed on the plate surface of the base unit 120 along its longitudinal direction. Angle members 144 are disposed on both side surfaces of the blade 142 of the blade unit 140 to define the insertion depth of the blade 142 into concrete by contacting the plate surface of the base unit 120.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a joint cutting device and a joint cutting method for cutting joints in concrete.

Background Art

[0002] In the construction of concrete pavement, during the period from placing the concrete until it hardens, it is necessary to perform a joint cutting operation as described in Japanese Patent Application Laid-Open No. 7-91061 (Patent Document 1) in parallel with the compaction operation for compacting the concrete. The joint cutting operation is an operation to prevent cracks and the like from occurring in the concrete pavement by forming joints in advance in the concrete pavement in view of the shrinkage of the concrete during hardening.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to cut joints in unhardened concrete pavement, a long joint cutting device having a T-shaped cross section is known. Handles for an operator to grip are respectively attached to both longitudinal ends of this joint cutting device. Then, at least two operators grip the handles and align the tip of the blade (knife edge) with the reference line drawn on the surface of the concrete pavement, and push the blade into the portion extending in the horizontal direction of the T shape to cut joints in the concrete pavement.

[0005] However, since the joint cutter was of an integral shape, it was heavy, and the labor of the operator for cutting joints in the concrete pavement was great. Also, when the operator used the joint cutter to cut joints in the concrete pavement, the reference line drawn on the surface was hidden by the joint cutter, making it difficult to position the joint cutter.

[0006] Therefore, an object of the present invention is to provide a joint cutter and a joint cutting method that can reduce the labor of the operator and facilitate positioning in the operation of cutting joints in concrete.

Means for Solving the Problems

[0007] The joint cutter has a base unit that is rectangular and long in plan view, and a blade unit having a blade for cutting joints in concrete. A slit through which the blade of the blade unit can be inserted is formed along the longitudinal direction on the plate surface of the base unit. Also, depth regulating members that abut against the plate surface of the base unit and regulate the insertion depth of the blade into the concrete are arranged on both side surfaces of the blade of the blade unit.

[0008] In the joint cutting method, using the joint cutter as described above, joints are cut in the concrete as follows. First, the base unit is placed on the surface of the concrete to be cut, and the blade of the blade unit is inserted into the slit formed in the plate surface of the base plate. Next, the blade unit is pushed toward the concrete until the depth regulating member of the blade unit abuts against the plate surface of the base unit.

Effects of the Invention

[0009] According to the present invention, in the operation of cutting joints in concrete using the joint cutter, the labor of the operator can be reduced and positioning can be facilitated.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0011] Hereinafter, with reference to the attached drawings, embodiments for carrying out the present invention will be described in detail. FIG. 1 and FIG. 2 show an example of a joint cutting device 100 for cutting joints in uncured concrete. Note that the joint cutting device 100 described below is merely an example to which the present embodiment is applicable, and should not be construed as being limited to its configuration. Therefore, it goes without saying that those skilled in the art can arbitrarily change and modify within the scope of the technical idea of the present embodiment.

[0012] The joint cutting device 100 has a base unit 120 disposed on the surface of the concrete to be joint cut and a blade unit 140 for cutting a joint in the concrete to be joint cut. Here, the blade unit 140 includes a blade 142 that is rectangular, elongated, and thin plate-shaped and is pushed from the surface of the concrete toward the inside to cut the joint.

[0013] As shown in FIG. 3, the base unit 120 includes a plate member 122 that is rectangular and elongated in plan view and a pair of ribs 124 that vertically rise from both end portions in the width direction perpendicular to the longitudinal direction of the plate member 122 to ensure strength. Therefore, the base unit 120 is formed in a rectangular and elongated shape in plan view. Here, the plate member 122 is cited as an example of the plate surface of the base unit.

[0014] A slit 122A that linearly extends substantially over the entire longitudinal length of the plate member 122 is formed at the central portion in the width direction of the plate member 122. Here, the slit 122A is configured to have a width through which the blade 142 can be inserted even if some concrete adheres to the blade 142 of the blade unit 140. Further, at both end portions in the longitudinal direction of the plate member 122, rectangular end members 126 that connect and integrate the upper surface of the plate member 122 and the opposing inner surfaces of the pair of ribs 124 are fixed. When the plate member 122, the pair of ribs 124, and the end member 126 are made of a steel plate, the end member 126 is joined to the plate member 122 and the pair of ribs 124 by welding, for example.

[0015] A handle 128 for an operator to grip and move or position the base unit 120 is attached to the upper end portion of the end member 126. In short, handles 128 for an operator to grip are respectively attached to both end portions in the longitudinal direction of the base unit 120.

[0016] The handle 128 includes a post portion 128A that is fixed while straddling the upper end portion of the end member 126, and a pair of handle portions 128B that extend from the tip end portion of the post portion 128A in the width direction of the plate member 122. The post portion 128A is attached so as to extend obliquely upward and outward from the upper end portion of the end member 126 as shown in FIG. 1, so as to facilitate gripping by the operator and to make it difficult for interference with the blade unit 140 to occur. Here, it is desirable that the handle portion 128B of the handle 128 has a circular cross section with a predetermined diameter so that it is easy for the operator to grip.

[0017] In addition, in an example shown in FIG. 3, the cross section of the post portion 128A is formed in a rectangular shape, but the cross section may be formed in a circular shape, an elliptical shape, or the like. Further, it is desirable that the post portion 128A and the handle portion 128B are formed in a hollow shape so as to reduce the weight of the base unit 120.

[0018] The base unit 120 is not limited to the above configuration, and may be configured by connecting both longitudinal ends of a pair of angle steels extending in parallel by the end member 126. Further, the base unit 120, the plate member 122, the pair of ribs 124, the end member 126, and the handle 128 are not limited to being made of steel, and may be made of plastic that is difficult for concrete to adhere to.

[0019] In addition, in order to stabilize the arrangement with respect to the surface of the concrete, as shown in FIG. 4, the dimension in the width direction of the plate member 122 may be increased, for example, a pair of ribs 124 may be formed in the central portion from the end in the width direction of the slit 122A to the end in the width direction of the plate member 122. In short, on the upper surface of the plate member 122 of the base unit 120, at least one rib 124 that extends parallel to the slit 122A and rises vertically from the upper surface of the plate member 122 may be integrated so as to ensure the strength of the plate member 122 and prevent it from bending. However, if the strength of the base unit 120 can be ensured only by the plate member 122, the pair of ribs 124 may not be provided for the purpose of weight reduction.

[0020] As shown in FIG. 5, the blade unit 140 includes, in addition to the blade 142, a pair of angle members 144 fixed to both side surfaces of the blade 142 as an example of a depth defining member that defines the insertion depth of the blade 142 into the uncured concrete. The pair of angle members 144 have a total length slightly shorter than that of the blade 142, and are attached so as to extend downward along both side surfaces starting from the upper end portion of the blade 142 and then extend vertically outward therefrom. Therefore, when the blade unit 140 is pushed into the concrete, the lower end surfaces of the pair of angle members 144 come into contact with the upper surface of the plate member 122 of the base unit 120, so that the insertion depth of the blade 142 into the concrete can be defined.

[0021] Here, the fixing of the pair of angle members 144 to the blade 142 can be performed using a fastener including, for example, bolts and nuts (not shown). Note that the blade 142 is preferably made of a lightweight plastic material to which concrete hardly adheres. Further, in the blade unit 140, instead of the angle member 144, for example, a member having an arbitrary shape that protrudes outward from both side surfaces of the blade 142, such as an angle pipe having a rectangular cross section, can be used to define the insertion depth of the blade 142 into the concrete.

[0022] Handles 146 for an operator to grip and move the blade unit 140 or cut joints in the concrete using the blade unit 140 are attached to both longitudinal ends of the pair of angle members 144. In short, handles 146 for an operator to grip are attached to both longitudinal ends of the blade unit 140, respectively, in the same manner as the base unit 120.

[0023] The handle 146 includes a channel-shaped fixing portion 146A that is fixed while straddling the blade 142 and a pair of angle members 144 that sandwich the blade 142, a post portion 146B that extends upward from the upper surface of the fixing portion 146A, and a pair of handle portions 146C that extend from the tip of the post portion 146B in the thickness direction of the blade 142. Here, it is desirable that the handle portion 146C of the handle 146 has a circular cross-section with a predetermined diameter so that it is easy for an operator to grip. The post portion 146B is attached so as to extend vertically upward from the upper surface of the fixing portion 146A as shown in FIG. 1 to make it difficult for interference to occur with the handle portion 128B of the base unit 120.

[0024] In addition, in an example shown in FIG. 5, the cross-section of the post portion 146B is formed in a rectangular shape, but the cross-section may be formed in a circular shape, an elliptical shape, or the like. Also, it is desirable that the post portion 146B and the handle portion 146C are formed in a hollow shape in order to reduce the weight of the blade unit 140.

[0025] At least the tip of the blade 142 is preferably formed in a tapered shape in which the plate thickness gradually decreases toward the tip as shown in FIG. 5. In this way, the surface pressure when inserting the blade 142 into the surface of the concrete increases, and the insertion of the blade 142 into the concrete can be facilitated. Here, it is desirable that the tapered shape of the blade 142 is symmetric with respect to the plate thickness direction in order to suppress the blade 142 from bending when a force acts in the plate thickness direction when the blade unit 140 is pushed into the concrete.

[0026] Regarding the blade unit 140, for the purpose of weight reduction similar to the base unit 120, in addition to the blade 142, the angle member 144 and the handle 146 may be made of plastic. Also, at a predetermined location of the blade unit 140, for example, at the upper end of the blade 142 or the post portion 146B of the handle 146, at least one vibrator (not shown) for supporting the pushing-in of the blade 142 into the concrete may be attached. Here, if the post portion 146B of the handle 146 of the blade unit 140 has a hollow shape, the vibrator may be accommodated therein. Instead of applying vibration by the vibrator, the blade unit 140 may be struck using a hammer or the like.

[0027] Next, with reference to FIGS. 6 to 11, the procedure for cutting joints in the uncured concrete CON using the joint cutter 100 will be described. It is assumed that ready-mixed concrete (commonly known as fresh concrete) has been previously placed on the construction road surface and a reference line REF has been previously drawn at the location where the joint is to be cut, as a prerequisite for cutting joints in the uncured concrete CON.

[0028] In the first step, two workers hold the handle 128 of the base unit 120 and place the base unit 120 on the surface of the uncured concrete CON to be cut for joints as shown in FIG. 6. At this time, since the slit 122A is formed in the plate member 122 of the base unit 120, the worker can easily position the base unit 120 while visually observing the reference line REF drawn on the surface of the concrete CON through the slit 122A. Also, since the worker only needs to operate the base unit 120, which is lighter than the conventional joint cutter, the labor of the work can be reduced.

[0029] In the second step, two workers grip the handle 146 of the blade unit 140, and insert the tip of the blade 142 into the slit 122A of the base unit 120 as shown in FIG. 7. At this time, since the slit 122A is formed in the plate member 122 of the base unit 120, the worker can easily position the tip of the blade 142 while visually observing the reference line REF drawn on the surface of the concrete CON through the slit 122A. Here, since the worker only needs to operate the blade unit 140 which is lighter than the conventional joint cutting device, the labor for the joint cutting work can be reduced.

[0030] In the third step, as shown in FIG. 8, two workers further push the blade unit 140 toward the concrete CON via the handle 146 until the lower end surface of the angle member 144 of the blade unit 140 abuts against the upper surface of the plate member 122 of the base unit 120. In a state where the lower end surface of the angle member 144 abuts against the upper surface of the plate member 122, even if the worker pushes the blade unit 140 toward the concrete CON, further intrusion of the blade 142 into the concrete CON is prevented. Therefore, the depth of the joint with respect to the concrete CON becomes constant, and the construction quality of the joint cutting can be improved. When changing the depth of the joint, for example, the attachment position of the angle member 144 with respect to the blade 142 may be changed, the size of the angle member 144 may be changed, or the blade unit 140 itself may be replaced.

[0031] In the fourth step, two workers lift the handle 146 of the blade unit 140 in a direction away from the concrete CON, and as shown in FIG. 9, extract the blade 142 of the blade unit 140 from the slit 122A of the base unit 120. And in the state where the blade 142 is extracted from the concrete CON, as shown in the figure, a joint JOI following the outer shape of the blade 142 is cut in the concrete CON. Here, when extracting the blade 142 from the concrete CON, since the lower surface of the base unit 120 is in contact with the surface of the concrete CON, this serves as a presser, and it is possible to suppress the corners of the joint JOI from being damaged when extracting the blade 142.

[0032] In the fifth step, two workers lift the handle 128 of the base unit 120 in a direction away from the concrete CON, and as shown in FIG. 10, remove the base unit 120 from the surface of the concrete CON.

[0033] In the sixth step, in order to prevent the uncured concrete CON from entering the joint JOI, the worker fills the joint JOI formed in the concrete CON with a joint material JMT as a temporary insert, as shown in FIG. 11. Here, as the joint material JMT, a well-known one made of a rectangular plate material may be used. Note that after the concrete CON has hardened, the joint material JMT as a temporary insert may be cut by an engine cutter to form a joint groove, and an injected joint material may be filled therein.

[0034] By sequentially performing the first step to the sixth step as described above, it is possible to form the joint JOI at the designated location of the concrete CON to be joint-cut. At this time, as the joint-cutting device 100, the worker only needs to operate either one of the base unit 120 and the blade unit 140, so there is no need to handle a heavy joint-cutting device as in the prior art, and the labor of the joint-cutting work can be reduced. Also, since the worker can visually confirm the reference line REF drawn on the surface of the concrete CON using the slit 122A of the base unit 120, the accuracy of the joint formation position can also be improved.

[0035] Those skilled in the art can easily understand that new embodiments can be created by omitting a part of the technical idea of the above-described embodiments, appropriately combining a part thereof, or replacing a part thereof with well-known techniques.

[0036] To give an example, the end member 126 of the base unit 120 is not limited to a rectangular shape and may have any shape capable of connecting the upper surface of the plate member 122 and the inner surfaces of the pair of ribs 124. Further, the pair of angle members 144 of the blade unit 140 is not limited to a configuration having a total length slightly shorter than that of the blade 142, and may have the same total length as the blade 142 or a total length slightly longer than that of the blade 142. Furthermore, regarding the procedure of cutting joints in the uncured concrete CON using the joint cutter 100, if the joint material JMT is not required, the sixth step may be omitted.

Description of Reference Numerals

[0037] 100... Joint cutter 120... Base unit 122... Plate member (plate surface) 122A... Slit 124... Rib 128... Handle 140... Blade unit 142... Blade 144... Angle member (depth defining member) 146... Handle CON... Concrete JOI... Joint

Claims

1. A base unit having a rectangular and elongated shape in a plan view; a blade unit having a blade for cutting joints in concrete; A jointing device having a slit through which the blade of the blade unit can be inserted is formed in the plate surface of the base unit along the longitudinal direction of the plate surface; A depth determining member is disposed on both sides of the blade of the blade unit to abut against a plate surface of the base unit and determine the insertion depth of the blade into the concrete. Joint cutting device.

2. A handle for an operator to grip is attached to each of both ends of the base unit and the blade unit in the longitudinal direction. The jointing device according to claim 1.

3. The blades of the blade unit are made of plastic. The jointing device according to claim 1.

4. At least the tip of the blade of the blade unit is formed in a tapered shape in which the plate thickness gradually decreases toward the tip. The jointing device according to claim 1.

5. At least one rib is integrated with the plate surface of the base unit, extending parallel to the slit and rising vertically from the plate surface. The jointing device according to claim 1.

6. The blade unit includes a vibrator. The jointing device according to claim 1.

7. Using the joint cutting device according to any one of claims 1 to 6, the base unit is placed on the surface of the concrete to be jointed, the blade of the blade unit is inserted into a slit formed in the plate surface of the base unit, and the blade unit is pushed toward the concrete until the depth-determining member of the blade unit abuts against the plate surface of the base unit, thereby cutting a joint in the concrete. Joint cutting method.

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