EP1669530B1

EP1669530B1 - Locking device for doors of industrial machines

Info

Publication number: EP1669530B1
Application number: EP05111556.6A
Authority: EP
Inventors: Fabio Zardini
Original assignee: Steelco SpA
Current assignee: Steelco SpA
Priority date: 2004-12-02
Filing date: 2005-12-01
Publication date: 2016-03-30
Anticipated expiration: 2025-12-01
Also published as: EP1669530A3; ITUD20040224A1; EP1669530A2

Description

FIELD OF THE INVENTION

The present invention concerns a clamping device for doors of industrial machines which generate, during the operative cycle, vapors, fumes or liquids that are hot and/or under pressure, toxic and polluting.
The invention is applied, preferably but not exclusively, on washer machines, for example of the industrial or hospital type used for washing and disinfecting medical and surgical instruments and equipment. The invention is also applied, in a substantially analogous manner, on washer machines in general, on sterilization devices, on domestic ovens or small industrial ovens, on painting or dyeing machines, or in any other similar or comparable application.
The clamping device according to the invention comprises first attachment means to temporarily attach the door to the body of the machine, and second attachment means including at least a mobile element, selectively moved by an actuator, and cooperating with a part of the door in order to guarantee a stable and water-tight mechanical closure.
To be more exact, the second attachment means determines a highly stable closure of the door, so as to prevent possible accidental openings during functioning, even when there are strong vibrations or stresses of other type on the door. Such accidental openings not only entail risks for the operators and possible damage to the work site, but also determine the interruption of the operating cycle of the machine and, in the case of sterilizers, the possible contamination of the objects housed inside the machine.

BACKGROUND OF THE INVENTION

Clamping devices for machines of an industrial type are known, for example washer machines, for closing a door, normally opening at the front, with respect to the frame or body of the machine, wherein first attachment means, for example with a spring latch, includes first elements associated with the frame and corresponding second elements associated with the door in order to determine its closure.
However, the attachment means does not guarantee the mechanical stability and security of the closure since, especially in cases where the washer machine is carrying out spinning cycles with strong vibrations, the closure of the door is not completely secure and therefore there may be an unwanted and dangerous opening of the machine while it is functioning.
Also because of the high temperatures reached inside the machines, it is necessary that the mechanical stability of the closure be guaranteed so as to prevent liquids, fumes and vapors from escaping, which could cause risks of accidents and injury to the operators and/or contamination and pollution of the environment, and also contamination of the objects being washed in the event of applications in sterilization and dis-infection devices.
This disadvantage has been solved in the state of the art, an disclosed in EP-A-1314840 , by using other mechanical closing means which normally consists of a mobile element of mechanical attachment, for example a rod or bar, disposed in proximity with the front edge of the frame. When the door is closed and held in position by the first attachment means, the mobile element of mechanical attachment is moved linearly by a solenoid, from an inactive position to an active position wherein it is inserted in a mating seating made on the door and clamps the latter mechanically.
One of the main disadvantages of these latest types of clamping device is that, in the event of an unexpected drop in the electric current, the solenoid, which in order to function must always be kept under tension, automatically puts the mechanical closing means in an open position, thus allowing liquids, fumes and vapors to escape from inside the machines.
Another disadvantage is that, during its functioning, the solenoid is subject to a dangerous over-heating precisely because it always operates under tension.
Solenoids are known which operate inversely, also called bistable, which keep the closing means of the door in a closed position. However, these inverse solenoids cannot be used for applications to which the present invention refers since, in order to guarantee a force sufficient to drive and hold the closing mechanism, they must be of large size, which is often incompatible with the constraints imposed by washer machines, particularly those used in hospitals.
Documents US-A-5760703 and US-A-4703960 discloses respectively a security device for truck doors and a power - operated window lock including a cam plate.
The preamble of claim 1 is based on document US5760703 .
The purpose of the present invention is to achieve a clamping device for an opening door of an industrial machine, which has limited size and which guarantees the stability and security of the mechanical and water-tight closure of the door with respect to the body of the machine even when the electric current accidentally fails.
Another purpose of the present invention is to achieve a clamping device whose components are not subjected to over-heating during use.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the main claim, while the dependent claims describe other innovative characteristics of the invention.
The clamping device according to the present invention comprises, in traditional manner, first attachment means including first retaining elements associated with the door and mating second retaining elements associated with the fixed body of the machine.
The device also comprises second stable mechanical attachment means which comprises a mobile attachment element, such as a rod or a bar, associated with the body of the machine, which is able to be selectively inserted in a mating seating disposed on the door, when the door is closed and retained in the correct position by the first attachment means. The mobile attachment element is associated with at least an actuator element able to move it substantially on a plane, from a first inactive position to a second active clamping position, wherein an operative extremity of the mobile attachment element cooperates with the seating on the door.
According to a characteristic feature of the present invention, the actuator element comprises cam means which can selectively be made to rotate around an axis thereof, by activating a drive member, such as for example an electric motor. The cam means is able to be selectively driven in order to move the attachment element linearly or rotationally on the plane on which it lies from said inactive position to the active position, and vice versa.
According to a preferential form of embodiment of the present invention, the axis of rotation of the cam means is inclined with respect to the plane of movement of the mobile attachment element; advantageously, this axis is substantially perpendicular with respect to said plane.
The use of the cam means allows to provide a drive member of much smaller size than that of the solenoids normally used, since the cam transmits the torque delivered by the drive member to the mobile attachment element, and determines a high level of thrust in order to move the latter between the inactive position and the active position, even when the motor has low power. Moreover, the cam constitutes a physical obstacle to retain the mobile element in the active position, thus guaranteeing that the door is maintained stable and watertight with respect to the body of the machine, also when the electric energy fails.
Furthermore, the drive member does not require a continuous electric feed, either to maintain the mobile attachment element in its active position, that is, in order to close the door, or to maintain it in its passive position, that is, when the door is open, which prevents its components from overheating.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other characteristics of the present invention will become apparent from the following description of a preferential form of embodiment, given as a non-restrictive example with reference to the attached drawings wherein:

fig. 1 is a three-dimensional view of a washer machine on which a clamping device according to the present invention is mounted;
fig. 2 is an exploded three-dimensional view of a device according to the invention;
fig. 3 is a view from above, partly in section, of a detail of fig. 1;
fig. 4 shows a variant of fig. 3.

DETAILED DESCRIPTION OF A PREFERENTIAL FORM OF EMBODIMENT

With reference to the attached figures, a clamping device 10 for washer machines of an industrial or hospital type, in this case a dishwasher for surgical instruments and surgical or hospital utensils, according to the present invention comprises mating first attachment means and second mechanical closing means 30.
Even if the invention is described with reference to a hospital washer machine it is obvious that the teaching thereof can be directly transferred to other types of industrial machines having analogous or comparable characteristics.
The washer machine on which the device 10 according to the present invention is mounted substantially consists of a frame or body 12 and a door 13 opening at the front. In this case, the frame 12 is substantially parallelepiped in shape and has an aperture 12a at the front which allows to load the material to be washed. Below the aperture 12a the door 13 is hinged, so that it can be selectively positioned between a substantially horizontal, completely open position, shown in fig. 1, which allows to load the material to be washed, and a substantially vertical closed position, in which it is not possible to access inside the machine.
The first attachment means comprises first elements 20 mounted on the frame 12 of the machine, in a central zone of the upper edge of the aperture 12a, which elements consist of a little metal block 14 on which a groove 15 is centrally made (figs. 1-3).
From the sides of the groove 15 two spheres 16 partly protrude towards the inside, and are held elastically in position thrust towards the outside by respective helical springs 17. Both the spheres 16 and the respective springs 17 are housed inside corresponding seatings 19 made laterally on the little block 14 and open onto the groove 15.
The springs 17 are kept stressed by corresponding pins 18 disposed transverse to the seatings 19.
The first attachment means also comprises second elements mounted on the door 13 in a position such that, when the door 13 is progressively taken to the closed position, the second elements 21 cooperate with the first elements 20 so as to determine a temporary condition of attachment and centering of an elastic type.
The second elements 21 mounted on the door 13 comprise a block 22, of a size mating with the groove 15, on whose sides two semi-spherical hollows 26 are made, in which, in the closed position of the door 13, the protruding parts of the spheres 16 are housed, (fig. 3), thrust elastically.
On one of the two sides of the block 22 there is also a seating 23 able during use to house an attachment element consisting of a rod 31, which will be described in more detail later.
The mechanical closing means 30 is mounted on the upper edge of the frame 12 and comprises the rod 31 and an associated actuator group 35.
The rod 31 is flattened, has a rectangular section, lies on a plane "P" and has an operative extremity 32 conformed as a tooth. Once the door 13 has been positioned closed, which is achieved by coupling the mating attachment means 20 and 21, the rod 31 is driven by the actuator group 35 in order to insert the tooth-like extremity 32 into the seating 23 of the block 22. The end-of-travel position of said rod 31 is defined by the abutment of one side 33 of the rod 31 and a corresponding side of said little block 14.
The actuator group 35 comprises an electric motor 38, of a substantially known type, and a cam 39 selectively made to rotate by the electric motor 38 around an axis of rotation "x", in this case substantially perpendicular to the plane "P" on which the rod 31 lies.
The cam 39 is disposed inside a corresponding through seating 37, made on the rod 31 substantially on the opposite side with respect to the operative extremity 32 of the latter.
The rotation of the cam 39 around the axis of rotation "x" inside the through seating 37 determines the displacement on the plane "P" of the rod 31 and hence the commanded insertion of the operative extremity 32 into the seating 23.
To be more exact, the through seating 37 has an amplitude greater than that needed for the cam 39 to rotate around its axis "x", so that, in the event of a malfunction or accidental blockage of the latter, for example due to lack of electric current, the user can easily intervene with a simple tool, for example a screwdriver, in order to move the rod 31 manually on the plane "P" and open the door 13.
The rod 31 also comprises, at the rear, a bent segment 34 with a return function, able to drive a microswitch, not shown in the drawings and disposed in proximity with the actuator group 35, in order to signal to the user the state of activation of the mechanical closing means 30.
The clamping device 10 according to the invention, since it is provided with an electric motor 38 that does not require a continuous electric feed in order to maintain the rod 31 in one or the other position, guarantees a greater watertight fit over time of the door 13, even in the presence of intense vibrations or stresses. This is because the packings (not shown) that cooperate with the perimeter of the door 13 when it is in the closed position are subject to greater pressure, and hence the watertight closure is ensured with respect to possible leakages of fumes, vapors or liquids.
It is clear however that modifications and/or additions of parts may be made to the clamping device 10 as described heretofore, without departing from the field and scope of the present invention an claimed.
For example, according to the variant shown in fig. 4, instead of moving linearly on the plane "P", due to the effect of the rotation of the cam 39, the rod 31 rotates in turn, always remaining on the plane "P", around a pin 40. In this solution, in fact, the rotation of the cam 39 inside the through seating 37 determines the rotation of the rod 31 around the pin 40 with the consequent insertion of the operative extremity 32 into the seating 23. In this case too, the through seating 37 has a greater amplitude than is necessary for the rotation of the cam 39.
In the variant shown in fig. 4 a helical spring 41 is also provided, which normally keeps the rod 31 in the inactive position. The helical spring 41 accompanies the return of the rod 31 from its active position to its inactive position.
It is also clear that, although the present invention has been described with reference to specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of clamping device for the doors of industrial machines, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

Claims

Clamping device for an opening door (13) of an industrial machine equipped with a frame (12), said device comprising first attachment means (20, 21) for a first clamping of said door (13) to said frame (12), and second mechanical closing means (30) including a selectively mobile attachment element (31) associated with said frame (12) and able to be inserted in a mating seating (23) provided on said door (13), said attachment element (31) being associated with an actuator group (35) able to move it on a plane (P) between an inactive position and an active clamping position wherein an operative extremity (32) thereof cooperates with said seating (23), wherein said actuator group (35) comprises cam means (39) able to be selectively made to rotate around an axis (x) thereof by means of activation of a drive member (38), and able to move said attachment element (31) on said plane (P);
characterized in that said attachment element (31) comprises a rod (31) lying on said plane (P), including a first operative extremity (32) conformed as a tooth able to be inserted into said seating (23), and a through seating (37), in which said cam means (39) is disposed and
in that said through seating (37) has a greater amplitude than is necessary for said cam mean (39) to rotate around said axis (x)
Device as in claim 1, characterized in that the axis (x) of said cam means (39) is inclined with respect to said plane (P) on which said attachment element (31) moves.
Device as in claim 1, characterized in that the axis (x) of said cam means (39) is substantially perpendicular with respect to said plane (P) on which said attachment element (31) moves.
Device as in any claim hereinbefore, wherein said seating (23) is made in a protruding block (22) able to be inserted in a mating groove (15) made in a little block (14) associated with the front edge of said frame (12), characterized in that said attachment element (31) includes an abutment side (33) able to rest on a mating side of said little block (14) in order to determine the depth of insertion of said operative extremity (32) in said seating (23).
Device as in any claim hereinbefore, characterized in that said attachment element (31) comprises at the rear part a segment (34) able to drive means to signal the state of activation of said mechanical closing means (30).
Device as in any claim hereinbefore, characterized in that said attachment element (31) is able to be displaced linearly on said plane (P) in order to move between said inactive position and said active position.
Device as in any claim from 1 to 6, characterized in that said attachment element (31) is able to rotate on said plane (P) around a pin (40) in order to move between said inactive position and said active position and is associated with elastic means (41) able to keep it normally in said inactive position.