JP7808079B2 - Joint cutting device and joint cutting method - Google Patents

Description

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

In concrete pavement construction, between the time the concrete is poured and the time it hardens, joint cutting work, as described in JP 7-91061 A (Patent Document 1), must be carried out in parallel with the compaction work to harden the concrete. Joint cutting is a process that takes into account the shrinkage of concrete as it hardens, and involves forming joints in the concrete pavement in advance to prevent cracks from occurring in the concrete pavement.

Japanese Unexamined Patent Publication No. 7-91061

A long joint cutting device with a T-shaped cross section is known for cutting joints in uncured concrete pavement. Handles are attached to both longitudinal ends of this joint cutting device for operators to grasp. At least two operators hold the handles and align the tip of the blade with a reference line drawn on the surface of the concrete pavement, while pushing the blade into the horizontal part of the T-shape to cut a joint in the concrete pavement.

However, because the joint cutting device was an integrated unit, it was heavy, and it required a lot of effort from the worker to cut joints in the concrete pavement. Furthermore, when the worker used the joint cutting device to cut joints in the concrete pavement, the reference lines drawn on the surface were hidden by the joint cutting device, making it difficult to position the joint cutting device.

The present invention aims to provide a joint cutting device and joint cutting method that reduces the labor required by workers and facilitates positioning when cutting joints in concrete.

The joint cutting device includes a base unit that is rectangular and elongated in plan view, and a blade unit that has a blade for cutting joints in concrete. The base unit has a longitudinal slit formed in its plate surface through which the blade of the blade unit can be inserted. Depth-regulating members are disposed on both sides of the blade of the blade unit, abutting against the plate surface of the base unit to regulate the insertion depth of the blade into the concrete. Handles are attached to both longitudinal ends of the base unit so that an operator can grasp them to move or position the device, and handles are attached to both longitudinal ends of the blade unit so that an operator can grasp them to move or cut joints.

In the joint cutting method, a joint cutting device such as the one described above is used to cut joints in concrete as follows: First, the base unit is placed on the surface of the concrete to be jointed, 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-determining member of the blade unit abuts the plate surface of the base unit.

The present invention reduces the labor required by workers and makes positioning easier when cutting joints in concrete using a joint cutting device.

FIG. 2 is a front view showing an example of a jointing device. FIG. 2 is a plan view showing an example of a jointing device. FIG. 2 is a partial perspective view showing an example of a base unit. FIG. 10 is a cross-sectional view of a main part showing a modified example of the base unit. FIG. 2 is a partial perspective view showing an example of a blade unit. FIG. 1 is an explanatory diagram of the first step of cutting joints in concrete. FIG. 10 is an explanatory diagram of the second step of cutting joints in concrete. FIG. 10 is an explanatory diagram of the third step of cutting joints in concrete. FIG. 10 is an explanatory diagram of the fourth step of cutting joints in concrete. FIG. 10 is an explanatory diagram of the fifth step of cutting joints in concrete. FIG. 10 is an explanatory diagram of the sixth step of cutting joints in concrete.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
1 and 2 show an example of a joint cutting device 100 for cutting joints in unhardened concrete. Note that the joint cutting device 100 described below is merely one example to which this embodiment can be applied, and should not be construed as being limited to this configuration. Therefore, it goes without saying that a person skilled in the art can freely change and modify the device within the scope of the technical concept of this embodiment.

The joint cutting device 100 has a base unit 120 that is placed on the surface of the concrete to be jointed, and a blade unit 140 that cuts joints in the concrete to be jointed. Here, the blade unit 140 includes a rectangular, elongated, thin blade 142 that is pushed from the surface of the concrete toward the back to cut the joints.

As shown in Figure 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 rise vertically from both ends of the plate member 122 in the width direction perpendicular to the longitudinal direction 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 an example of a plate surface of the base unit.

A slit 122A is formed in the center of the width of the plate member 122, extending linearly over substantially the entire length of the plate member 122 in the longitudinal direction. The slit 122A is configured to have a width that allows the blade 142 of the blade unit 140 to pass through even if some concrete is attached to the blade 142. Furthermore, rectangular end members 126 are fixed to both longitudinal ends of the plate member 122, connecting and integrating the upper surface of the plate member 122 with the opposing inner surfaces of the pair of ribs 124. When the plate member 122, the pair of ribs 124, and the end member 126 are made of steel plate, the end member 126 is joined to the plate member 122 and the pair of ribs 124, for example, by welding.

A handle 128 is attached to the upper end of the end member 126 so that an operator can grasp it to move or position the base unit 120. In other words, a handle 128 is attached to each of the longitudinal ends of the base unit 120 so that the operator can grasp it.

The handle 128 includes a post portion 128A that straddles and is fixed to the upper end of the end member 126, and a pair of handle portions 128B that extend from the tip of the post portion 128A in the width direction of the plate member 122. The post portions 128A are attached so that they extend diagonally upward and outward from the upper end of the end member 126, as shown in FIG. 1, to make it easier for the operator to grip and to reduce interference with the blade unit 140. Here, it is desirable that the handle portions 128B of the handle 128 have a circular cross-section with a predetermined diameter to make it easier for the operator to grip.

In the example shown in Figure 3, the cross section of the post portion 128A is rectangular, but the cross section may be circular, elliptical, or other shapes. It is also desirable that the post portion 128A and the handle portion 128B be hollow to reduce the weight of the base unit 120.

The base unit 120 is not limited to the above configuration, but may also be configured by connecting both longitudinal ends of a pair of parallel angle steels with an end member 126. Furthermore, the base unit 120, including the plate member 122, pair of ribs 124, end member 126, and handle 128, is not limited to being made of steel, and may also be made of plastic, which is less likely to adhere to concrete.

In order to stabilize its placement on the concrete surface, as shown in Figure 4, the width of the plate member 122 may be increased, and a pair of ribs 124 may be formed in the center from the widthwise end of the slit 122A to the widthwise end of the plate member 122, for example. In short, at least one rib 124 that extends parallel to the slit 122A and rises vertically from the top surface of the plate member 122 may be integrated into the top surface of the plate member 122 of the base unit 120 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 with the plate member 122 alone, it is not necessary to provide a pair of ribs 124 in order to reduce weight.

As shown in Figure 5, the blade unit 140 includes, in addition to the blade 142, a pair of angle members 144 fixed to both sides of the blade 142 as an example of a depth-regulating member that determines the insertion depth of the blade 142 into unhardened concrete. The pair of angle members 144 have an overall length slightly shorter than that of the blade 142, and are attached so that they start at the upper end of the blade 142, extend downward along both sides, and then extend vertically outward from there. Therefore, when the blade unit 140 is pushed into the concrete, the lower end surfaces of the pair of angle members 144 abut against the upper surface of the plate member 122 of the base unit 120, thereby determining the insertion depth of the blade 142 into the concrete.

The pair of angle members 144 can be fixed to the blade 142 using, for example, fasteners including bolts and nuts (not shown). It is desirable that the blade 142 be made of a lightweight plastic material to which concrete does not easily adhere. In addition, instead of the angle members 144, the blade unit 140 can use any shaped member that protrudes outward from both sides of the blade 142, such as a square pipe with a rectangular cross section, which can determine the insertion depth of the blade 142 into the concrete.

Handles 146 are attached to both longitudinal ends of the pair of angle members 144 so that an operator can grasp them to move the blade unit 140 or use it to cut joints in concrete. In other words, similar to the base unit 120, handles 146 are attached to both longitudinal ends of the blade unit 140 so that an operator can grasp them.

The handle 146 includes a channel-shaped fixed portion 146A that straddles and is fixed to the blade 142 and a pair of angle members 144 that hold it; a post portion 146B that extends upward from the top surface of the fixed 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, the handle portion 146C of the handle 146 preferably has a circular cross-section with a predetermined diameter so that it is easy for the operator to grip. As shown in FIG. 1, the post portion 146B is attached so that it extends vertically upward from the top surface of the fixed portion 146A to reduce interference with the handle portion 128B of the base unit 120.

In the example shown in Figure 5, the cross section of the post portion 146B is rectangular, but the cross section may be circular, elliptical, or other shapes. It is also desirable that the post portion 146B and the handle portion 146C be hollow to reduce the weight of the blade unit 140.

As shown in Figure 5, it is desirable that at least the tip of the blade 142 be formed in a tapered shape, with the thickness gradually decreasing toward the tip. This increases the surface pressure when inserting the blade 142 into the surface of the concrete, making it easier to insert the blade 142 into the concrete. Here, it is desirable that the tapered shape of the blade 142 be symmetrical in the thickness direction to prevent bending due to force acting in the thickness direction when the blade unit 140 is pressed into the concrete.

As with the base unit 120, the blade unit 140 may be made of plastic not only for the blade 142 but also for the angle member 144 and handle 146, in order to reduce weight. At least one vibrator (not shown) that supports the pressing of the blade 142 into concrete may be attached to a predetermined location on the blade unit 140, such as the upper end of the blade 142 or the post 146B of the handle 146. If the post 146B of the handle 146 of the blade unit 140 is hollow, the vibrator may be housed therein. Instead of applying vibrations with a vibrator, the blade unit 140 may be struck with a hammer or the like.

Next, with reference to Figures 6 to 11, the procedure for cutting joints in unhardened concrete CON using the joint cutting device 100 will be described. Note that, as a prerequisite for cutting joints in unhardened concrete CON, it is assumed that ready-mixed concrete (commonly known as ready-mixed concrete) has been poured onto the construction road surface in advance, and that a reference line REF has already been drawn at the location where the joint will be cut.

In the first step, two workers grasp the handles 128 of the base unit 120 and place the base unit 120 on the surface of the unhardened concrete CON to be jointed, as shown in Figure 6. At this time, because a slit 122A is formed in the plate member 122 of the base unit 120, the workers can easily position the base unit 120 while visually checking the reference line REF drawn on the surface of the concrete CON through the slit 122A. Furthermore, because the workers only need to operate the base unit 120, which is lighter than conventional jointing devices, the labor required for the work can be reduced.

In the second step, two workers grasp the handles 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 Figure 7. At this time, because the slit 122A is formed in the plate member 122 of the base unit 120, the workers can easily position the tip of the blade 142 while visually checking the reference line REF drawn on the surface of the concrete CON through the slit 122A. Here, the workers only need to operate the blade unit 140, which is lighter than conventional joint cutting devices, thereby reducing the effort required for joint cutting work.

In the third step, as shown in Figure 8, two workers further push the blade unit 140 toward the concrete CON using 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. When 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, the blade 142 is prevented from penetrating further into the concrete CON. Therefore, the depth of the joint in the concrete CON remains constant, improving the quality of the joint cutting. Note that the depth of the joint can be changed, for example, by changing the attachment position of the angle member 144 relative to the blade 142, changing the size of the angle member 144, or replacing the blade unit 140 itself.

In the fourth step, two workers lift the handle 146 of the blade unit 140 away from the concrete CON and remove the blade 142 of the blade unit 140 from the slit 122A of the base unit 120, as shown in Figure 9. Then, with the blade 142 removed from the concrete CON, a joint JOI is cut in the concrete CON that follows the outline of the blade 142, as shown in the same figure. Here, when the blade 142 is removed from the concrete CON, the underside of the base unit 120 abuts against the surface of the concrete CON, which acts as a clamp and prevents the corners of the joint JOI from being damaged when the blade 142 is removed.

In the fifth step, two workers lift the handle 128 of the base unit 120 away from the concrete CON, and remove the base unit 120 from the surface of the concrete CON, as shown in Figure 10.

In the sixth step, to prevent unhardened concrete CON from entering the joints JOI, a worker fills the joints JOI formed in the concrete CON with temporary insert joint material JMT, as shown in Figure 11. Here, a well-known rectangular plate-shaped joint material may be used as the joint material JMT. Once the concrete CON has hardened, the temporary insert joint material JMT may be cut with an engine cutter to form a joint groove, which can then be filled with injection joint material.

By sequentially performing steps 1 through 6 as described above, a joint JOI can be formed at a specified location on the concrete CON to be jointed. At this time, the worker only needs to operate either the base unit 120 or the blade unit 140 as the joint cutting device 100, eliminating the need to handle a heavy joint cutting device as in the past and reducing the labor required for joint cutting. Furthermore, the worker can use the slit 122A in the base unit 120 to visually confirm the reference line REF drawn on the surface of the concrete CON, thereby improving the accuracy of the joint formation position.

A person skilled in the art will readily understand that new embodiments can be created by omitting parts of the technical ideas of the above embodiments, combining parts as appropriate, or replacing parts with well-known technology.

To cite one example, the end member 126 of the base unit 120 is not limited to a rectangular shape, and may have any shape that allows for connection between the upper surface of the plate member 122 and the inner surfaces of the pair of ribs 124. Furthermore, the pair of angle members 144 of the blade unit 140 are not limited to having an overall length slightly shorter than that of the blade 142, and may have the same overall length as the blade 142 or an overall length slightly longer than that of the blade 142. Furthermore, in the procedure for cutting joints in unhardened concrete CON using the joint cutting device 100, if joint material JMT is not required, step 6 may be omitted.

100... Joint cutting device 120... Base unit 122... Plate member (plate surface)
122A... Slit 124... Rib 128... Handle 140... Blade unit 142... Blade 144... Angle member (depth regulation member)
146...Handle CON...Concrete JOI...Joint

Claims (7)

A base unit that is rectangular and long in 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 that abuts against a plate surface of the base unit and determines the insertion depth of the blade into concrete ;
Handles are attached to both ends of the base unit in the longitudinal direction so that an operator can grasp them to move or position the base unit,
Handles are attached to both ends of the blade unit in the longitudinal direction so that an operator can grip them to move or cut joints.
Joint cutting device. The blades of the blade unit are made of plastic.
The jointing device according to claim 1. 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. At least one rib is integrated with the plate surface of the base unit, the rib extending parallel to the slit and rising vertically from the plate surface.
The jointing device according to claim 1. The blade unit includes a vibrator.
The jointing device according to claim 1. The handles of the base unit are attached so as to extend obliquely upward and outward from both ends of the base unit in the longitudinal direction,
The handles of the blade unit are attached so as to extend vertically upward from both ends of the blade unit in the longitudinal direction.
The jointing device according to claim 1. 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.
Jointing method.