Safety device for automatic interruption of movable element on cutting machine

Abstract

A safety device (10) for the automatic interruption of a movable element on a cutting machine, in particular for the automatic interruption of a movable element on a machine (12) for the automatic continuous cutting of sheet-like material, the machine comprising at least one movable beam (16) carrying one or more cutting units; the device comprises at least two ultrasonic sensors (18, 20) applied to the beam (16), respectively oriented to detect the presence of a body or a part of the body, such as a hand, of an operator in an area covered by a pulsed beam generated by the sensors themselves during positive and negative movements of the beam (16).

Description

Technical Field

[0001] The invention relates to a safety device for the automatic interruption of a moving element on a cutting machine.

[0002] More specifically, the present invention relates to a safety device, particularly suitable for machines for cutting flexible materials, which automatically and immediately interrupts the moving element or cutting beam if the operator inserts his / her hands or other body parts into the working area. Background Art

[0003] As is known, there are many types of machines for cutting various materials, such as leather, hides, fabrics, synthetic materials, composite materials, porous materials and technical materials, in order to obtain semi-finished products with a predetermined shape; the material to be cut can also consist of two or more homogeneous layers or of heterogeneous materials. Systems or machines for the continuous automatic cutting of sheet materials are widely used, starting from die-cutting machines provided with an oscillating arm moved and driven by an operator; such machines comprise a large working surface on which is usually arranged at least one beam carrying one or more cutting units. The beam slides along relative guides extending at two parallel sides of the working surface. The operator in charge of checking the cutting of the material placed on the working surface can sometimes himself, unintentionally, put his / her hand into the area of ​​the surface itself affected by the sliding of the beam, with the risk of injury due to accidental contact with the beam itself in motion.

[0004] Various protection systems are known which are suitable for preventing the operator from coming into contact with the moving parts of the cutting machine; for example, there are barriers formed by heavy and expensive fences which delimit the periphery of the machine, as well as photoelectric barriers or infrared photocells, by which the machine is forced to stop immediately if the operator enters the protected area, intercepting the light beam. This second embodiment assumes also a non-negligible inconvenience related to the bulk of the column placed near the machine and incorporating the light beam transmitter / receiver device.

[0005] From US 2008 / 066596 a cutting machine is known in which the control of the movement speed of the cutting head is improved in order to increase the productivity of the cutting machine with limited cost increase; the products are cut one by one from a plate-like element relative to which the cutting head moves.

[0006] EP 4052872 relates to a cutting machine comprising means designed to produce a photoelectric barrier; said barrier is at least partially located above the level of the working surface. Summary of the invention

[0007] Therefore, the object of the present invention is to provide a safety device for the automatic interruption of movable elements on a cutting machine, in particular, the safety device is used for the automatic interruption of movable elements on a machine comprising at least one movable beam carrying one or more cutting units, which safety device can avoid the above-mentioned disadvantages.

[0008] More particularly, an object of the present invention is to provide a safety device to prevent possible contact between the moving beam and the hands or arms or other parts of the body of the operator responsible for supervising the cutting operation.

[0009] Another object of the invention is to provide a device as defined above, capable of immediately interrupting the deflection of the movable arm of the cutting machine when a part of the operator's body enters the protection zone created by the device itself.

[0010] Last but not least, an object of the present invention is to allow the movable arm of the cutting machine to resume operation quickly when the interference of the operator's hand or arm with the protection zone created by the above-mentioned safety device is eliminated.

[0011] A further object of the invention is to provide a safety device which does not require the creation of bulky and expensive fences to delimit the entirety of the cutting machine at the periphery.

[0012] A further object of the invention is to provide a safety device which does not create obstacles in the area around or near the cutting machine which prevent access to the machine itself or which make the machine itself inaccessible.

[0013] A further object of the invention is to provide the user with a safety device for a cutting machine comprising at least one mobile beam suitable for ensuring a high level of resistance and reliability over time, besides being for example easy and economical to manufacture.

[0014] The above and other objects are achieved by the safety device of the present invention according to the main claim. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The structural and functional features of the safety device of the present invention can be more clearly understood from the following description, in which reference is made to the accompanying drawings / diagrams showing preferred and non-limiting embodiments, in which:

[0016] Figure 1 schematically depicts an axonometric view of a cutting machine provided with the safety device of the present invention, wherein an operator is placed near the cutting machine;

[0017] Figure 2is a schematic perspective view of a safety device according to the invention, which is intended to be mounted on a movable beam of a cutting machine, at the end of the beam facing the operator;

[0018] Figure 3 A functional block diagram of the control logic of the safety device of the present invention is depicted. DETAILED DESCRIPTION

[0019] First, refer to the above-mentioned figure. Figure 2 The safety device of the present invention, schematically shown generally at 10, is advantageously coupled to Figure 1 A cutting machine is shown at 12; the cutting machine 12 comprises: a working surface 14 on which the material to be cut is arranged; and at least one beam 16 extending transversely above the working surface 14 to carry one or more cutting units (not shown) of a known type.

[0020] According to the invention, the beam 16 is provided with at least two ultrasonic sensors 18, 20 on the head facing the operator, the two ultrasonic sensors 18, 20 being oriented to detect the presence of the operator's body or body parts, such as hands, during positive movement and during negative movement, respectively; "positive movement" being a displacement of the beam 16 in which the beam 16 is guided from a rest position to move towards the central part of the working surface 14 in order to cut the material by one or more cutting heads provided with the beam 16. Conversely, "negative movement" is a displacement in which the beam 16 is moved back in the opposite direction towards the central part of the working surface 14 until the beam 16 returns to the rest position. Preferably, as Figure 2 As shown, the beam 16 is provided with four ultrasonic sensors, two sensors 18, 18' being oriented to detect during negative movement, and two sensors 20 and 20' being oriented to detect during positive movement. The ultrasonic sensors detect the presence of an object without contact, emitting high-frequency sound wave pulses that propagate through the air in a cone-shaped beam; thus, this configuration covers a large area of ​​the cutting machine 12 starting from the front edge 12' of the cutting machine 12. Since the pulse emitted by the sensors is reflected when it detects an object or surface without contact, the possible presence of the operator's hand or other part of the body in the area covered by the cone-shaped pulse beam generates a signal that is detected by the sensors themselves and used to immediately interrupt the excursion of the beam 16. In practice, as Figure 3 As shown, the sensors present on the beam 16 constitute input elements of a programmable safety logic which commands the control system to interrupt the movement. Thus, the risk of collision between the beam and the operator is avoided.

[0021] As can be seen from the above, the advantages of the present invention are obvious.

[0022] The safety device of the invention allows to carry out an automatic and immediate interruption of the beam carrying the cutting unit when the presence of the operator's hand or other part of the body in the zone affected by the deflection of the beam is detected by sensors, both during positive and negative movements. Furthermore, said safety device does not involve any major obstruction close to the cutting machine, which remains unobstructed throughout its entire periphery.

[0023] Although the present invention has been described above with particular reference to one embodiment given only by non-limiting example in the embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art from the above description. Therefore, the present invention is intended to include all modifications and variations falling within the scope of protection of the appended claims.

Claims

1. A safety device (10) for the automatic interruption of a moving element on a cutting machine, in particular, the safety device is used for the automatic interruption of a moving element on a machine (12) for automatic continuous cutting of sheet material, the machine comprising at least one moving beam (16) carrying one or more cutting units, the safety device being characterized in that at least two ultrasonic sensors (18, 20) are fixed to the beam (16), at least two of the ultrasonic sensors (18, 20) being respectively oriented to detect the presence of an operator's body or a part of the body, such as a hand, in the area covered by the pulse beam generated by the sensor itself.

2. The safety device according to claim 1, characterized in that: At least two of the ultrasonic sensors (18, 20) detect the presence of the operator's body or body parts during positive and negative movement of the beam (16).

3. The safety device according to claim 1, characterized in that: The safety device comprises two pairs of ultrasonic sensors (18, 20) and (18', 20'), which are fixed to the head of the beam (16), the head of the beam (16) facing the operator and located near the front edge (12') of the machine (12).

4. The safety device according to claim 3, characterized in that: The sensors (18, 20) and / or (18', 20') fixed to the beam (16) form input elements of a programmable safety logic suitable for commanding a control system to momentarily interrupt the movement of the beam itself.

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