The present invention generally relates to a movable safety screen device for preventing any type of risk for operators when handling a printer and more particularly for preventing risks for operators when handling hazardous areas of a printing unit of the printer when it is in operation. The present invention also relates to a printer with such movable safety screen device.
Flexographic printers equipped with one or more safety screen devices are known. The main function of these safety screen devices is to prevent the operator or the person handling the machine from being able to access the hazardous areas when the machine is in operation or when parts of the machine are performing a certain type of movement, thus assuring that the operator is risk-free. The hazard in said hazardous areas is usually caused by the automatic movements of some elements of the machine in any of the operating modes thereof.
It is common to have different types of safety screen devices in a printer and more specifically in a printing unit of the printer. One such screen is a fixed screen device which includes, for example, a plurality of safety screens fixed or anchored to a static structure of the machine and more specifically to a structure of a printing unit. A safety screen device is called a “fixed” screen device when a tool is required to be able to remove it. Another type of safety screen device can be a movable screen device which does not require any tool for being removed since it can be moved manually by an operator.
The movable safety screen devices are normally provided with an electronic safety element connected to an electronic safety module of the machine. Therefore, when the movable screen of the safety device is removed by an operator, the electronic safety element is disconnected and this means that the electronic safety module of the machine deactivates or stops all the movements of any element which may cause any risk particularly in the area where the movable screen of the safety device has been withdrawn.
Movable safety screen devices installed in the printing units of the printer where the movable screens are assembled such that they must pivot or swivel about a horizontal axis to be moved between a safe position and a withdrawn position are known. The movement can be performed manually by an operator and once the screen is in the withdrawn position it stays in a position where the operator can access any of the different parts of the printing group quite easily.
One drawback associated with the safety screen devices installed in a printer and more specifically in a printing unit of the printer which pivot or swivel about a horizontal axis is that even though the safety screen is moved to the withdrawn position by means of said pivoting with respect to a horizontal axis, the area that can be accessed by the operator is partially blocked by the safety screen itself due to the fact that the screen is not fully withdrawn from the desired area. This is because when the screen is in the withdrawn position the horizontal axis about which the screen pivots or swivels remains in the same position as when the screen is in the safe position.
The present invention aims in overcoming the preceding and other drawbacks by providing a movable safety screen device applicable to a printer and more specifically to the printing unit thereof. One or more safety screen devices comprising one or more screens designed and assembled such that they can be withdrawn leaving an area completely free for accessing different parts of the printing unit can be installed in a printer. Said one or several movable safety screens provide the printing unit with the suitable safety elements to prevent any risk for the operators.
The screens can be similar to one another in shapes and sizes although they do not necessarily have to be identical. All the screens are formed by a flat body which can be made from a transparent material or can have dies, windows or openings to allow seeing through same while at the same time preventing the passage of any member of the human body. The screens are generally rectangular and comprise a certain type of rail for a lineal guide system. The rails can be individual parts installed in the body of the screen or can be formed integrally with the body of the screen. Another part of the lineal guide system comprises wheels, guide bearings, or similar elements which are fixed in a static part of the machine, such as a structure thereof. In one embodiment, the wheels, guide bearings, or similar elements are fixed, for example, at the front of a base of the printing unit of the printer.
The rails of the screen are parallel to and are separated from one another and the wheels, guide bearings, or similar elements are coupled to the rails such that the screen is supported in a movable projecting manner by the wheels, guide bearings, or similar elements. Therefore, by means of its rails the screen can be moved by the sliding or rolling existing between the rails and the wheels or guide bearings fixed in the structure of the machine between a safe position in which the screen prevents the access to a hazardous area of the printer and a withdrawn position in which the screen is withdrawn from said hazardous area.
This horizontal movement of the screen allows clearing the space which it occupied in the safe position completely when the screen is in the withdrawn position, the operator being able to access the different areas of the printing unit perfectly. In one embodiment, the flat body of the screen is assembled in a vertical plane and the rails are arranged horizontally one in its upper part and another in its lower part. In one embodiment, the screen comprises an auxiliary screen element connected to same by one or more hinges allowing said auxiliary screen element to pivot with respect to the screen about a horizontal axis when the screen is in the safe position. Therefore, in the safe position for example, the screen can have a main section arranged in the vertical plane and another auxiliary section arranged in a horizontal plane.
The movable safety screen device further comprises an electronic safety device in connection with an electronic safety module of the printer configured for deactivating or stopping the movement of any element of the printer in the hazardous area if the screen is not in said safe position.
When the screens are in the safe position, a safety element fixed to the screen is arranged in a position suitable for cooperating with another safety element fixed to the structure of the machine such that the electronic safety module detects the coupling of the two safety elements and allows normal printer operation. When one of the screens moves to the withdrawn position, the safety element fixed to the screen is disconnected from the other safety element fixed to the structure of the machine and the electronic safety module deactivates or stops any movement of any element of the printing group involved in order to prevent any risk for the operator who can safely access the area from where the screen has been removed.
When the screen is closed in the safe position, it is supported in cantilever at one of its ends by the guide elements fixed to the screen and to the structure. At the other end of the screen opposite the end on which it is supported, there is a support and positioning element such as a conical element positioned for cooperating with another support and positioning element fixed to the structure when the screen reaches the safe position. The screen has a securing member fixed at the same end thereof having the support and positioning element. This securing member is positioned for cooperating with another securing member fixed to the structure when the screen reaches the safe position. In one embodiment, these two securing members comprising at least one magnetic element and are selected for exerting a strong enough securing force for securing the screen in the safe position and at the same time allowing the screen to be moved to the withdrawn position by a small thrusting force exerted manually thereon.
The foregoing and other features and advantages will be more obvious from the following detailed description of embodiments in reference to the attached drawings, in which:
First referring to
Each of the movable safety screen devices 30 comprises a screen 3 linked to a first rack 10a of the fixed structure 10 of the printer 40 by linking means comprising first guide elements installed in said first rack 10a of the structure 10 and complementary second guide elements installed in the screen 3 for allowing a linear movement of the screen 3 between a safe position, in which the screen 3 prevents the access to a hazardous area of the printer 40, and a withdrawn position, in which the screen 3 is withdrawn from said hazardous area.
In the embodiment shown, the mentioned first and second guide elements are arranged for allowing the mentioned linear movement of the screens 3 in a horizontal direction parallel to the printing roller of the printer 40 and each screen 3 has a flat screen body located in a vertical plane.
Each movable safety screen device 30 further comprises an electronic safety device 4a, 4b in connection with an electronic safe module (not shown) of the printer 40 configured for deactivating or stopping the movement of any element of the printer 40 in the hazardous area if the screen 3 is not in said safe position as will be described in greater detail below.
As can be seen in the embodiment shown in
In the printer 40 of
As better shown in
The mentioned second guide elements comprising first and second rails 3a, 3b fixed to the body of the screen 3. The mentioned first and second rails 3a, 3b are parallel and are separated from one another by a distance according to the separation between the first and second bearings 2a, 2b, 2c, 2d. The first rail 3a is coupled to the two first bearings 2a, 2b and the second rail 3b is coupled to said two second bearings 2c, 2d. The distance of separation between both the first bearings 2a, 2b and between both the second bearings 2c, 2d is significantly shorter than the length of the rails 3a, 3b and of the screen 3 such that the screen 3 is supported in a movable projecting manner by the first and second bearings 2a, 2b, 2c, 2d coupled to the first and second rails 3a, 3b.
In the illustrated embodiment and as better shown in
As seen in enlarged detail in
In
Given that in the safe position the screen 3 has most of its length supported in cantilever, each screen 3 comprises a support and positioning hole 8a formed in a front tab 7 of the body of the screen 3 (
Therefore, the end of the screen 3 furthest from the first and second bearings 2a, 2b, 2c, 2d when the screen 3 is in the safe position is supported and centred by the support and positioning lug or lugs 8b fixed in the second rack 10b and inserted in the support and positioning hole or holes 8a. Alternatively, other pairs of support and positioning elements arranged in the screen 3 and in the second rack 10b of the structure 10, respectively, configured and arranged for coupling to and cooperating with one another when the screen 3 reaches the safe position can be used for supporting and positioning the end of the screen 3 in the safe position.
Each screen 3 further comprises a first securing member 9a positioned for cooperating with a second securing member 9b fixed to the structure 10 when the screen 3 reaches the safe position. These first and second securing members 9 are formed for exerting, when they are coupled, a strong enough securing force for securing the screen 3 in the safe position and at the same time allowing the screen 3 to be moved to the withdrawn position by a thrusting force exerted manually thereon. In the embodiment shown, the first securing member 9a comprises a magnetic element, such as a permanent magnet or the like, fixed to said front tab 7 of the body of the screen 3 (
The mentioned front tab 7 located at the same end of the screen 3 where the support and positioning holes 8a are formed and the first securing member 9a is fixed acts as a stop 7 which is positioned for interfering with the first rack 10a of the structure 10 or with another element fixed to the structure 10 when the screen 3 reaches the withdrawn position. Therefore, the stop 7 establishes an end of run for the screen 3 in the withdrawn position and prevents the rails 3a, 3b from decoupling from the bearings 2a, 2b, 2c, 2d.
The aforementioned electronic safety device comprises a first safety element 4a fixed to the screen 3, for example by means of a support 5, and a second safety element 4b fixed to the first rack 10a of the structure 10. Said first and second safety elements 4a, 4b are arranged in respective positions selected such that the first and second safety elements 4a, 4b of the electronic safety device are coupled to one another when the screen 3 is in the safe position.
When the first and second safety elements 4a, 4b are coupled they cooperate with one another and with the electronic safety module of the printer 40 for allowing it to operate normally. When the screen moves from the safe position to the withdrawn position, the first and second safety elements 4a, 4b are decoupled and the electronic safety module of the printer 40 acts for deactivating or stopping the movement of any element in the hazardous area.
Alternatively, the second safety element 4b can be fixed to the second rack 10b of the structure 10 instead of the first rack 10a, in which case the first safety element 4a is fixed to the screen 3 in a suitable position for coupling same when the screen 3 reaches the safe position.
Modifications and variations from the embodiment shown and described will be obvious to a person skilled in the art without departing from the scope of the present invention as defined in the attached claims.
Number | Date | Country | Kind |
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P201000479 | Apr 2010 | ES | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/ES2011/000041 | 2/23/2011 | WO | 00 | 11/19/2012 |