Patent Application
20250128461
The present invention relates to a safety mat configured to detect intrusion of a worker by the presence or absence of a load, a mold clamping device including the safety mat, and an injection molding machine including the safety mat.
A pressure-sensitive switch mat that detects the presence or absence of a load, that is, a safety mat, is installed in a building where security is required to detect intrusion of a suspicious person, or is installed in an industrial machine to detect a worker entering the machine.
There are various types of pressure-sensitive switch mats, some of which are configured as follows. That is, the pressure-sensitive switch mat includes a bottom sheet provided on a bottom surface, a surface sheet made of a flexible elastic insulating material such as a rubber sheet, and a pressure-sensitive conductive sheet provided between the bottom sheet and the surface sheet. The pressure-sensitive conductive sheet is made of a rubber material that is an insulator, and conductive particles mixed into the rubber material. When the pressure-sensitive conductive sheet is compressed, the conductive particles therein come into contact with each other at a compressed portion, thereby establishing electrical conductivity. The surface sheet and the bottom sheet are each provided with an electrode film, and the electrode film is in contact with the pressure-sensitive conductive sheet. Accordingly, when a load acts on the surface sheet, a portion where the load is applied is deformed, the pressure-sensitive conductive sheet becomes conductive due to compression, and the electrode films on the surface sheet and bottom sheet become conductive. The presence or absence of a load can be detected by applying a voltage to the electrode films in advance.
Patent Literature 1 proposes a pressure-sensitive switch mat of a different type. The pressure-sensitive switch mat described in Patent Literature 1 includes a step board portion and a plurality of tubular portions formed on a back surface side of the step board portion, and is integrally formed from rubber. A fluid is sealed in the tubular portion, and the fluid is connected to a pressure sensor via a connecting pipe. When a load acts on a surface of the step board portion, a portion is elastically deformed and the tubular portion on the back surface side is compressed. This causes the pressure of the fluid to increase and the increase is detected by the pressure sensor.
The pressure-sensitive switch mat is excellent in that it can reliably detect the presence or absence of a load no matter where the load acts. For example, if the pressure-sensitive switch mat is installed on a bed on which a fixed platen and a movable platen are provided in a mold clamping device, the intrusion of a worker can be detected reliably, so that safety can be ensured. However, there are also problems. When a load acts on a surface of the pressure-sensitive switch mat, the portion is deformed and the load is detected. In other words, at least the surface sheet is flexible and is made of rubber or the like. In this case, if a high temperature substance adheres to the surface sheet, a portion thereof will melt and be damaged. For example, in a case where the pressure-sensitive switch mat is provided on a bed of a mold clamping device, if molten resin falls and adheres to the mat, that portion will be damaged.
In view of the above problems, an object of the present disclosure is to provide a safety mat that will not be damaged even if a high temperature substance adheres thereto, and a mold clamping device and an injection molding machine provided with such a safety mat.
Other problems and novel features will become apparent from description of the present description and the accompanying drawings.
The present inventors have found that the above problem can be solved by configuring a safety mat as follows. That is, the present disclosure relates to a safety mat including: a pressure-sensitive switch mat whose surface is made of a flexible sheet; a step board disposed on the pressure-sensitive switch mat; and a plurality of load transferring members arranged at intervals between the pressure-sensitive switch mat and the step board. A load acting on the step board is detected by the pressure-sensitive switch mat via the plurality of load transferring members.
According to the present disclosure, it is possible to provide a safety mat in which the pressure-sensitive switch mat is protected by the step board so as to be prevented from being damaged even if a high temperature substance adheres thereto.
Hereinafter, specific embodiments will be described in detail with reference to the drawings The present disclosure is not limited to the following embodiments. In order to clarify the description, the following description and the drawings are simplified as appropriate. In the drawings, the same elements are denoted by the same reference numerals, and repeated description thereof is omitted as necessary. In addition, hatching may be omitted to avoid complicating the drawings.
A safety mat according to the present embodiment includes: a pressure-sensitive switch mat having a surface formed of a flexible sheet and configured to detect presence or absence of a load; a step board disposed on the pressure-sensitive switch mat; and a plurality of load transferring members arranged at intervals between the pressure-sensitive switch mat and the step board, in which a load acting on the step board is detected by the pressure-sensitive switch mat via the plurality of load transferring members.
Further, a mold clamping device according to the present embodiment includes: a fixed platen fixed to a bed; and a movable platen slidably provided on the bed and driven in a direction toward and away from the fixed platen, in which the safety mat is provided on the bed.
Further, an injection molding machine according to the present embodiment includes: an injection device configured to inject a resin; and a mold clamping device configured to clamp a mold, in which the mold clamping device includes: a fixed platen fixed to a bed; and a movable platen slidably provided on the bed and driven in a direction toward and away from the fixed platen, and in which the safety mat is provided on the bed.
The present embodiment will be described.
As shown in
The mold clamping device 2 according to the present embodiment includes a fixed platen 9 fixed on a bed B, a mold clamping housing 10 that slides on the bed B, and a movable platen 11 that also slides on the bed B. The fixed platen 9 and the mold clamping housing 10 are coupled by a plurality of, for example, four tie bars 13, 13, . . . . The movable platen 11 penetrates the tie bars 13, 13, . . . and is slidable toward the fixed platen 9. A mold clamping mechanism 15 is provided between the mold clamping housing 10 and the movable platen 11. The fixed platen 9 and the movable platen 11 are respectively provided with molds 16 and 17. Accordingly, when the mold clamping mechanism 15 is driven, the molds 16 and 17 are opened and closed. The mold clamping mechanism 15 may be a hydraulically driven mold clamping cylinder, and the type is not limited. In the present embodiment, a toggle mechanism is adopted.
That is, the mold clamping device may include a mold clamping housing provided slidably on the bed, a plurality of tie bars coupling the fixed platen and the mold clamping housing, and the toggle mechanism provided between the mold clamping housing and the movable platen.
The mold clamping device 2 according to the present embodiment has a safety mat 20 according to the present embodiment which will be described in detail below. More specifically, the safety mat 20 is laid on the bed B and is provided between the fixed platen 9 and the movable platen 11. The safety mat 20 is connected to the controller 4. Although not shown in
The pressure-sensitive switch mat 23 may be of various types available on the market. In the present embodiment, the pressure-sensitive switch mat 23 is of a type that includes a pressure-sensitive conductive sheet. Although not shown in
The step board 25 is provided so as not to prevent high temperature substances from adhering to the surface sheet of the pressure-sensitive switch mat 23 and causing damage. The material of the step board 25 is not critical, but it is preferable to use a metal plate such as an aluminum plate, that is, an aluminum alloy plate, a stainless steel plate, or a steel plate. This is because the metal plate has high heat resistance and does not deteriorate even if a high temperature substance falls thereon. A surface of the step board 25 is subjected to an uneven processing 26 for sliding.
The step board is preferably made of an aluminum plate or a stainless steel plate or a steel plate.
A plurality of load transferring members 28, 28, . . . are provided on a back surface of the step board 25. The load transferring members 28, 28, . . . may be made of any material. In the present embodiment, the members are formed in a plate shape from a rubber material, that is, an elastomer. The plurality of load transferring members 28, 28, . . . are arranged at intervals and are attached to the back surface of the step board 25. The load acting on the step board 25 acts on the pressure-sensitive switch mat 23 via the small load transferring members 28, 28, . . . , so that the load can be accurately detected. In the present embodiment, reinforcing ribs 29, 29, . . . are attached to the back surface of the step board 25, and the load transferring members 28, 28, . . . are fixed to the reinforcing ribs 29, 29, . . . .
In this way, it is preferable that the step board is provided with a plurality of reinforcing ribs, and the plurality of load transferring members are fixed to the reinforcing ribs.
In the safety mat 20 according to the present embodiment, the bottom board 21 and the step board 25 have a larger area than the pressure-sensitive switch mat 23. Accordingly, peripheral edges of the bottom board 21 and the step board 25 protrude outward beyond the pressure-sensitive switch mat 23. The bottom board 21 and the step board 25 are connected to each other by a plurality of elastic support members 32, 32, . . . at the portions protruding outward. The elastic support member 32, 32, . . . may be made of any material as long as it is capable of elastically supporting the step board 25. In the present embodiment, the member is made of a spring 33.
As described above, it is preferable that the safety mat includes: a bottom board having an area larger than that of the pressure-sensitive switch mat and disposed below the pressure-sensitive switch mat; and a plurality of elastic support members, in which the plurality of elastic support members are provided on the bottom board while avoiding the pressure-sensitive switch mat, and support the step board, and in which the elastic support members are configured to be compressed when a load is applied to the step board.
The clastic support member is preferably made of a spring.
Operation of the safety mat 20 according to the present embodiment will be described. The safety mat 20 according to the present embodiment is as shown in
A worker stands on the safety mat 20. Then, as shown in
In the safety mat 20 according to the present embodiment, the step board 25 is on a top surface. Accordingly, the pressure-sensitive switch mat 23 is less likely to be damaged. In the injection molding machine 1 (see
The safety mat 20 according to the present embodiment can be modified in various ways.
The step board 25 have been described as preferably being made of metal. Alternatively, the step board may be made of a polyimide resin, a ceramic composite material, or a fiberglass composite material. These are materials used as heat insulating boards. Accordingly, even if a high temperature substance adheres to the step board 25, heat conduction to the surface sheet of the pressure-sensitive switch mat 23 can be prevented, and the surface sheet can be protected. It has been described above that the load transferring member 28 may be made of any material. Similar to the step board 25, the load transferring member 28 may be made of a polyimide resin, a ceramic composite material, or a fiberglass composite material. Alternatively, the load transferring member 28 may be made of metal. That is, the load transferring member may be made of rubber or metal.
Although the invention made by the present inventor has been specifically described above based on the embodiments, it is needless to say that the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the invention. The plurality of examples described above may be appropriately combined.
According to the present disclosure, it is possible to provide a safety mat that will not be damaged even if a high temperature substance adheres thereto, and a mold clamping device and an injection molding machine provided with such a safety mat.
Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention.
The present application is based on Japanese Patent Application No. 2022-011326 filed on Jan. 27, 2022, and the contents thereof are incorporated herein as reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-011326 | Jan 2022 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2023/000338 | 1/10/2023 | WO |
