Patent Publication Number: US-11388988-B2

Title: Lifting table and a method of operating and cleaning a lifting table

Description:
This application is a National Stage application of International Application No. PCT/EP2019/077352, filed Oct. 9, 2019, the entire contents of which are incorporated herein by reference. 
     This application claims priority under 35 U.S.C. § 119(a) to European Patent Application No. 18199365.0, filed on Oct. 9, 2018, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a lifting table comprising a table top having a polygonal contour and including an upper and a lower face, a lifting mechanism and a base where the lifting mechanism is connected to the table top and includes an actuator for raising and lowering the table top. The base is configured for supporting the lifting mechanism. Two side members are positioned along the sides of said table top and at least one switch element being positioned below said upper face. The side members are connected to the table top below said upper face allowing the side member to be moved between a first position, wherein the side members are disengaged from the switch element and a second position where the side members activate the switch element, hereby preventing displacement of the table top relative to the base. 
     Description of the Related Art 
     At present is has been known to use lifting tables having a lifting mechanism for different lifting tasks within the food industries or the pharmaceutical manufacturing industries. 
     However, during the manufacturing process, there is a need for cleaning and/or disinfecting the equipment. By cleaning the equipment, it is possible to avoid contamination during subsequent production of another product or the same product. The product can be bulk food, goods, and pharmaceutical products to be consumed or used by human. Typically, the manufacturing equipment has to be cleaned on a daily basis, preferably at the end of the work day. A cleaning process can be achieved by using a low-pressure water-jetting unit for spooling off the leftovers in the form of raw materials followed by a chemical cleaning process using a cleaning foam, which makes it easier to clean hard-to-reach areas such as corners. 
     Even after the equipment has be cleaned with water possibly in combination with a standard cleaning product, there might be a need to disinfect the equipment in a subsequent step e.g. applying the chemical product onto the lifting table. 
     One problem associated with the tasks of cleaning and disinfecting a lifting table is that at least the cleaning process but also the disinfecting process is quite time consuming as the table top includes a lot of corners and hard-to reach areas and the cleaning fluid or the cleaning foam has a limited capability to penetrate into those corners (blind area). 
     The objective problem of the present invention is to provide an improvement in relation to a lifting table, where hard-to-reach area(s) have been removed. 
     A further object is to improve cleaning or disinfecting of a lifting table. 
     It is an object of the present invention to provide a lifting table, where a least two side members are arranged along two adjoining sides of the table top, wherein the ends of said two side members are arranged with a distance in between each other, such as 1-8 mm. 
     SUMMARY OF THE INVENTION 
     The anti-squeezing mechanism will include at least two side members being arranged along the sides of the lifting table and one switch element being connected to a lower face of the table top. The elongated elements are movable individually relative to the table top. 
     The lifting table according to the present invention has the advantage, that by arranging two adjoining side members along two adjoining sides of the table top, it is possible in combination with at least one switch element to achieve an anti-squeezing mechanism, which does not include a blind area where the material or dust can be accumulated. By arranging two side members with a distance in between each other, it is furthermore possible for the cleaning foam to penetrate into the gap created by two adjoining side members. 
     The anti-squeezing mechanism will consist of at least two side members being arranged along the sides of the lifting table and one switch element being connected to a lower face of the table top. The elongated elements are movable individually relative to the table top. 
     The lifting table can be used together with other manufacturing equipment as one or more lifting tables can be integrated into a production line, such as a process line or pallet transport line, where a lifting mechanism can be used for elevating a pallet to a higher level, such as from a first level to a second level. 
     In the context of this application, the term “elongated element” is used to describe an element being part of the lifting mechanism of the lifting table, where each of the elongated elements includes a front end and a back end can be fixated relative to the table top or the base. The elongated element could also be referred to as a leg. 
     In an embodiment according to a first aspect of the present invention, the number of side members corresponds to the number of sides of the table top, preferably a table top having a rectangular geometry with four side members positioned along the side of the table top. By using a number of side members corresponding to the number of sides of the table top, it is possible to cover all of the sides of said lifting table, hereby providing an anti-squeezing mechanism that ensures that an operator is not able to get squeezed during a lowering operation of said lifting table. By using four elongated elements connected to the table top, it is possible to cover all sides of the table top. 
     In an embodiment according to a first aspect of the present invention, the side members are connected to each other by a number of brackets. The bracket is used for fixating the side members relative each other, hereby achieving an improvement when the lifting table has to be assembled. The bracket provides a further advantage as it is possible to maintain the distance, also referred to as the gap, between two adjoining elongated elements of the anti-squeezing mechanism. 
     In an embodiment according to a first aspect of the present invention, the table top includes a number of side walls arranged along the sides of the table top, wherein the side walls extend perpendicularly from the upper face of the table top, wherein at least one side wall includes a number of slots arranged at a first distance from the side end(s) of the side wall. The table top can include a number of side walls arranged along the sides of the table top to avoid any blunt and/or shape edges. To enhance the possibility for achieving a proper cleaning of the anti-squeezing mechanism, the side wall includes a number of apertures or slots, which will enable a cleaning foam to penetrate into the space between a side wall of the table top and a elongated element of the anti-squeezing mechanism. 
     In an embodiment according to a first aspect of the present invention, wherein each side member is provided with an aperture for allowing the side members to be moved relative to the table top. By arranging one or more apertures in the side members, it is possible to displace the side members relative to the side walls of the table top for allowing the side members to be moved between a first position, wherein the side members are disengaged from the switch element and a second position where the side members activate the switch element, hereby preventing displacement of the table top relative to the base. 
     In an embodiment according to a first aspect of the present invention, the side members are provided for covering the slots of the side walls and/or the side members are provided with a side member end extending towards the center of the table top, preferably at an angle of 30-70 degree. Preferably, the side members are arranged perpendicularly to the table top and therefor the ends of the side members should not include any sharp edges and/or ends. The above can be achieved, if the ends of the elongated elements extend towards the center of the table top, when the elongated elements are mounted relative to the table top. 
     In an embodiment according to a first aspect of the present invention, the lifting table further includes a leg element being pivotably connected to the table top at a first leg element end, preferably to a lower face, wherein a fixation element is provided on the base for engaging a connecting element positioned on the leg element, preferably on the opposite end of the first leg element end. The leg element can be retracted from an inactive position to an active position allowing the operator of the lifting table to position the table top into an inclined angle, when the lifting table has to be cleaned or disinfected. 
     In an embodiment according to a first aspect of the present invention, lifting table further includes an arm connected to the base ( 40 ) at a first end, wherein a fixation element is arranged to the lower face of the table top for engaging a connecting element being positioned on the arm, wherein the arm is pivotably connected to the base. 
     In an embodiment according to a first aspect of the present invention, lifting table further includes a separate arm being configured for engaging the base and the lifting mechanism. 
     In an embodiment according to a first aspect of the present invention, the lifting mechanism is connected to the table top through a number of fixating mounting brackets for allowing the elongated elements of the lifting mechanism to rotate relative to the table top at a first end, wherein each elongated element furthermore includes a roller positioned at the opposite end of the first end. By using a lifting mechanism including a number of rollers, it is possible to obtain a guide movement of the table top as the lifting mechanism is only partially fixated to the base and the table top via a number of fixating mounting brackets. 
     In an embodiment according to a first aspect of the present invention, the lifting mechanism includes a number of elongated elements being connected to the table top and said elongated elements are arranged to form a scissor mechanism, wherein the structural part such as the elongated elements are made from a galvanized metal. By using stainless metal, such as AIS3 304 or higher alloy for the structural parts of the lifting table, it is possible to obtain a lifting table, which is suitable for operating in a food and/or pharmaceutical production facility. Stainless steel has an increased corrosion resistance, particularly against chlorides and other industrial solvents. Due to its non-reactive qualities, stainless steel is also used in the manufacture of medical surgical instruments. Alternative 300-series grades can contain up to 7 percent molybdenum. They provide even better chloride resistance, but such heavy-duty resistance is only necessary in industrial or high concentration exposure conditions. It is also possible to use a galvanized metal or stainless steel, in particular hot galvanized steel and/or plastic or plastic-coated steel, for the structural parts of the lifting table. 
     In an embodiment according to a first aspect of the present invention, the lifting table further includes a controller being connected to the actuator and the switch element, wherein said switch element is configured for deactivating the actuator. The controller can generally be configured for allow the lifting mechanism to be displaced and the controller is furthermore configured for receiving input from one or more switch elements. The switch element could be a sensor e.g. switch, pressure sensor, light sensor or wire sensor. The switch element is preferably positioned on the lower face of the table top, to disable operation of the lifting mechanism, such as lowering of the table top, by deactivating the actuator connected to the lifting mechanism. 
     In an embodiment according to a first aspect of the present invention, the actuator is a hydraulic actuator connected to a power source for supplying hydraulic fluid to the actuator and/or motor driven spindle connected to a power source for supplying hydraulic fluid to the actuator. Hydraulic actuators or motor driven spindles have the capability to be used for different lifting tasks, such as lifting a number of bucks or barrels containing the product used in a manufacturing line. Pneumatic belt driven actuator or other drives can be used. 
     In another embodiment of the invention, the table top can have a variety of shapes, configurations and sizes. A table top generally has a square or rectangular shape; however, it can be appreciated that the table top can have other configurations (e.g., circular, oval, polygonal, etc.). Generally, the table top has a surface area and shape that can accommodate the dimensions of commonly sized pallets; however, this is not required. In one non-limiting configuration, the upper face of the table top has a generally rectangular or square shape and a width of about 0.5-4 m and a length of about 0.5-10 m. 
     In the context of this application, the term “table top” has be used to define a top element of a lifting table. It is therefore within the scope of the present invention that the element could have been referred to as a platform, top support surface or upper surface element, etc. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       References are made to the accompanying drawings that form a part of this disclosure, and which illustrates the embodiments in which the lifting table and methods described in the specification can be practiced. 
         FIG. 1  illustrates a lifting table with which the embodiments described in this specification can be practiced, according to some embodiments. 
         FIG. 2A  show a table top according to one preferred embodiment. 
         FIG. 2B  shows a close-up view of the table top shown in  FIG. 2A   
         FIG. 3A  shows a table top according to one preferred embodiment. 
         FIG. 3B  shows a cross-sectional view (BB) of the table top shown in  FIG. 3A . 
         FIG. 3C  shows a close-up view of the table top shown in  FIG. 3A . 
         FIG. 3D  shows a cross-sectional view (CC) of the table top shown in  FIG. 3A . 
         FIG. 4A  shows a cross-sectional view of the table top shown in  FIG. 3A . 
         FIG. 4B  shows one close-up view of the table top shown in  FIG. 4A . 
         FIG. 4C  shows one close-up view of the table top shown in  FIG. 4A . 
         FIG. 5A  shows a front view of the table top shown in  FIG. 1 . 
         FIG. 5B  shows a side view of the table top shown in  FIG. 1 . 
         FIGS. 6A-6   d  illustrates a method of adjusting the inclination of the table top of said lifting table in a step prior to cleaning and disinfected said lifting table. 
     
    
    
     DETAILED DESCRIPTION 
     The invention will now be explained in more detail by means of exemplary embodiments with reference to the drawings. 
     Attention is first directed to  FIG. 1 , of the drawings. In  FIG. 1 , the lifting table  10  includes a table top  12  with a polygonal contour and the lifting table includes an upper  11  and a lower face  13 , a lifting mechanism  20  and a base  40 . The lifting mechanism  20  is connected to the table top  12  and an actuator  30  is used for raising and lowering the table top  12 . The base  40  is configured for supporting and possibly guiding the lifting mechanism  20 . The base  40  shown in the FIGS. includes four base elements; it is however possible to have a base  40  having two rails being interconnected for allowing the lifting mechanism  20  to be guided on said rails and the base  40  can furthermore include a number of levelling feet to avoid the base from being in direct contact with the floor in the production facility. The table top could include a turn table or roller conveyer (not shown) for positioning of items arranged on top of the table top  12 . In the situation that the lifting table  10  is used for lifting personal, the lifting table will also include one or more hand rails (not shown). 
       FIG. 5A  shows a front view of the table top shown in  FIG. 1  whereas  FIG. 5B  shows a side view of the table top shown in  FIG. 1 . In both figures, the lifting table is extended to a maximum position for the lifting table as the actuator is extended to an outer position. 
     In the embodiment shown in  FIGS. 1, 2A, 5A-6D , the number of side members  62 ,  63 ,  64 ,  65  corresponds to the number of sides of the table top  12 . The table top  12  has a rectangular geometry with four side members  62 ,  63 ,  64 ,  65  being positioned along the side of the table top  12 . 
     The lifting mechanism  20  includes four elongated elements  22 , 24 , which are connected to the table top  12  and said elongated elements  22 , 24  are arranged to form a scissor mechanism. The elongated elements are made from a galvanized metal. 
     A controller  50  can be used by an operator to control the lowering and lifting operation of the lifting table  10  and the controller may be connected to the actuator  30  and the switch element(s)  80  can be positioned under the table top  12 , preferably connected to the side wall of the table top, directly to the table top or directly to the side member  62  table top. When one or more of side members  62 , 63 , 64 , 65  are moved, the switch element is engaged and a signal is send to the controller. The actuator can be a hydraulic actuator with a piston rod  32  being connected to the lifting mechanism. It is possible to have just one switch element or to have several switch elements positioned on the lower surface of the table top. Independently of the number of switch element used, each switch element is configured to send a signal to the controller in order to deactivating the actuator  30  and hereby prevent further movement of the lifting mechanism. 
     The lifting table  10  includes an actuator  30  such as a hydraulic actuator connected to a power source for supplying hydraulic fluid to the actuator. Instead, another possible option could be a motor driven spindle, a belt driven actuator or a pneumatic actuator connected to a power source for supplying power to the actuator  30 . 
     Referring now to  FIG. 2A , four side members  62 ,  63 ,  64 ,  65  are positioned along the sides of the table top  12  and a corresponding number of switch elements  80  are positioned below the lower face  13 . The side members  62 ,  63 ,  64 ,  65  are connected to the table top  12  below the lower face  13  allowing the side members  62 ,  63 ,  64 ,  65  to be moved between a first position (shown in  FIGS. 2B, 4A-4C ), where the side members  62 ,  63 ,  64 ,  65  are disengaged from the switch element  80  and a second position (not shown) where the side members  62 ,  63 ,  64 ,  65  activate the switch element  80 , hereby preventing displacement of the table top  12  relative to the base  40 . 
     Referring now to  FIG. 2B , the side members  62 ,  63  are connected to each other by brackets  68 . The bracket  68  is used to maintain the distance d 1 , also referred to as the gap, between two adjoining elongated elements  62 ,  63  of the anti-squeezing mechanism and the bracket  68  furthermore enables that four elongated elements can be retained relative to one another. In one embodiment, four side members  62 ,  63 ,  64 ,  65  are positioned along the table top, the gap formed between two adjoining side members  62 ,  63 ,  64 ,  65  can be the same or it is also possible to vary the distance d 1  and hereby achieving different gaps at the corners of the lifting table. 
     Referring now to  FIG. 2A  and  FIG. 2B , the two side members  62 ,  63  are arranged along two adjoining sides of the table top  12 , where the ends of the two side members  62 ,  63  are arranged with a distance d 1  in between each other, such as 1-8 mm (shown in  FIG. 2B ). 
     Referring now to  FIGS. 3A-3D , the table top  12  includes a number of side walls  14  arranged along the sides of the table top  12  and the side walls  14  extend perpendicularly to the upper face  11  of the table top  12 . As shown in  FIGS. 3A and 3C , it is possible to have a number of slots  16  in only one of the side walls  14 . As shown in  FIG. 3B , the slot  16  can be arranged at a second distance d 2  from the side end of the side wall  14 . The height h of a wall part  621  of a side member  62  is larger than the second distance d 2  and as the second distance d 2  defined by the distance from the side end of the side wall  14  to the slot  16  is smaller than the height h of a wall part  621  of a side member  62 , it is possible to cover the slots  16 , hereby preventing the operator from blocking the slots e.g. by hanging different obstacles, such as hooks onto the table top  12 . The angle β between the wall part  621  of a side member  62  and the first inclined part  622  is between 190-265 degrees. It should be appreciated that the gap Gs shown in  FIG. 3C  is only optional, as the invention could also work on a lifting table having a table top  12  without any corners being provided with a slit or aperture. 
     The height h of the wall part  621  of the side members  62  is provided for covering the slots  16  of the side walls  14  and each side members  62  can furthermore be provided with a inclined part  623  extending towards the center of the table top  12 , preferably at an angle of 30-70 degree relative to the side wall  14 , such as an angle of 30-50, 50-80 or 40-60 degrees. By using a curved, C-shaped or V-shaped geometry on the end of the side member  62 , it is also possible to prolong the time and enhance the tacky effect of a cleaning foam, which unlike ordinary cleaning fluids allows the cleaning foam to work on the surfaces of the table top. This means that foam cleaning can be effectively used for cleaning both the anti-squeezing mechanism and the side walls of the table top with a minimal effort. It should be noted that above description of the side member  62  with reference number  62  also applies to the other side members  63 ,  64 ,  65 . 
     In one embodiment, the side member  62  is provided with a curved end, such a v-shaped end (shown in  FIG. 3B ) or C-shaped end (not shown). The v-shaped end includes a first inclined part  622  extending in a first direction and a second inclined part  623  in a second direction. The second inclined part  623  can be arranged at an angle α of 45-90 degrees relative to the first inclined part  622 . 
     Referring now to  FIGS. 4A-4C , each side member  62 ,  63 ,  64 ,  65  can be provided with a number of apertures  64  for allowing the side members  62 ,  63 ,  64 ,  65  to be moved relative to the table top  12 . Reference is made to  FIG. 4B , which shows that the curved end referred to in  FIG. 3B  could include a blunt end part  624   
     Referring now to  FIGS. 6A-6D , the lifting mechanism  20  includes two sets of elongated elements  22 . Each set of legs includes two elongated elements  22 , 24 . The two elongated elements  22 , 24  in each set are connected together. The connection can be any type of connection that enables the two elongated elements to move relative to one another about the connection. 
     As illustrated in  FIGS. 1, 5A-5B and 6A-6D  the connection is generally positioned at or near the mid-longitudinal region of the elongated elements; however, this is not required. 
     Referring now to  FIGS. 6C-6D , a roller or a wheel  27 , 28  is connected to the front end  222 ,  242  of the elongated elements  22 , 24 . The wheels or rollers, when used, enable the front end  222 , 242  of elongated elements  22 , 24  move along the base of the lifting table  10 , hereby allowing the lifting mechanism  20  to move between an elevated or raised position and non-elevated position. As can be appreciated, as the lifting mechanism  20  moves from a non-elevated position to a raised position, the front end  222 , 242  of legs move toward the back end of the elongated elements legs  22 ,  24 . Likewise, as the lifting mechanism  20  moves from an elevated or raised position to a non-elevated or lower position, the front end  222 ,  242  of the elongated elements  22 , 24  move away from the back end  221 , 241  of the elongated elements  22 , 24 . The wheels or roller facilitate in such movement of the elongated elements  22 , 24  over the base  40 . The table top could also include a number reinforcement bars  35  arranged on the lower face of the table top  12 . The base  40  includes a number of side walls  42  for guiding the lifting mechanism  20  during movement of the table top  12  relative to the base  40 . 
     Referring now to  FIGS. 6A-6D , the lifting table  10  further includes a leg element  72  being pivotably connected to the table top  12  at a first leg element end, preferably to a lower face  13 , wherein a fixation element  44  is provided on the base  40  for engaging a connecting element  74  positioned on the leg element  72 , preferably on the opposite end of the first leg element end. 
     As mentioned with reference to the previous figures, the lifting mechanism  20  is connected to the table top  12  through a number of fixating mounting brackets  28 , 29  for allowing the elongated elements  22 , 24  to rotate relative to the table top  12  at a first end and each elongated element  22 , 24  furthermore includes a roller  26 , 27  being positioned at the opposite end of the first end. The first end would also be referred to as the back end, whereas the front end of the elongated element  22 , 24  would be referred to as the second end of the elongated element  22 , 24 . 
     Operation of the lifting table  10  can be performed by an operator either directly or remotely by using a wireless communication unit connected to the controller of the lifting table. According to a second aspect to the present invention, it is possible to activate a safety mode when at least one side member  62 ,  63 ,  64 ,  65  is moved from a first position, where all side members  62 ,  63 ,  64 ,  65  are disengaged from the switch element  80  to a second position, where the side member  62 ,  63 ,  64 ,  65  engages the switch element  80 , hereby preventing further displacement of the table top  12  relative to the base  40 . 
     In the event that all four side members  62 ,  63 ,  64 ,  65  are connected to each other by using four brackets  68 , there will be no individual displacement of the side member  62 ,  63 ,  64 ,  65  relative to the table top  12 . 
     The cleaning of the table may include a physical cleaning step and optional a chemical cleaning step. The physical cleaning step may be performed by an operator, who spools the lifting table with a water jet, preferably a low-pressure water jet for preventing the contamination or dirt attached to the lifting table from being spread further. The operator would spool the lifting table at an angle between 5-90 degrees relative to the surface to be cleaned. In a subsequent chemical cleaning step, the operator would apply a chemical cleaning product onto the surface of said lifting table. The cleaning and disinfecting process can be performed in combination with each other, as it is also possible only to perform the cleaning or disinfecting step. 
     When it is time to clean the lower face  13  of the lifting table, the table top of the lifting table can be adjusted to an inclined angle relative to the ground floor. By adjusting the table top to an inclined portion, the operator may perform a visual inspection prior to the actual of performing the cleaning and/or disinfecting process. The inclined position of the table would also allow the operator to have a better work position, when he has to clean the underside of the lifting table. The cleaning and/or disinfecting process of the lifting table  10  can involve the following steps:
         operating the lifting table  10  in a first operational mode, wherein the first operational mode includes the steps of:
           i. raising the table top  12  to a first elevated position relative to the base  40  by operating the actuator  30  and the lifting mechanism  20 , wherein the first elevated position can be the maximum extension height for the lifting table  10  (shown in  FIG. 6A );   ii. retracting the leg element  72  from a first retracted position to a first extended position (shown in  FIG. 6A );   iii. fixating the leg element  72  in a first fixating position (shown in  FIG. 6B , where the leg element  72  engages the fixation element  44  on the base  40 , see  FIG. 6 d   );   
           operating the lifting table  10  in a second operational mode, wherein the table top  12  is lowered to a second height position by operating the actuator  30  and the lifting mechanism  20 , wherein the leg elements causes the table top  12  to be moved into a first inclined position as the platform is moved from a first elevated position to a second elevated position, wherein the table top  12  will be positioned at an angle of 30-60 degrees relative to the base  40  in the second elevated position.       

     As would be evidently from  FIG. 6D , the leg element  72  is retained relative to the base  40  by the fixation element  44  positioned on the base  40  and the roller arranged on the front end of the elongated element  22 , 24 . 
     In a subsequent step, the method can include raising the table top  12  into a substantially vertical position by operating the actuator according to a third operational mode, wherein the actuator exerts a force onto the lifting mechanism  20  being connected to the lower face of the table top  12 . 
     The cleaning product used could be a cleaning foam, where a dosing unit having a nozzle is used for applying the cleaning foam on the contaminated surface. The chemical product can be mixed with water from a pressure cleaner. The foam must be allowed some time (typically 10-30 min) to fight dirt etc. on a lifting table according to the present invention. 
     Depending on the type of contamination, the waiting time varies. For example, if there is a fight against dried dairy product dirt, the waiting time will often be longer for an effective result. In case of highly resistant contamination, it may be necessary to help with scouring fungus or the like. 
     The structural parts of the lifting table would in one embodiment have a surface, which have be treated using an electropolishing method. By using an electropolishing process on the surface of the structural parts of the lifting table, it is possible to achieve a surface finish with very low surface roughness values, hereby reducing the tendency for dirt or dust from adhering to the surface of the table top. The most common electrolytes for the electropolishing of stainless steel are varying concentrations of phosphoric and sulphuric acid, and occasionally additives such as chromic acid. 
     During the step of cleaning the table, the lifting table could be positioned in at least two positions during the cleaning process. The first position would be a top position, where the leg element is retracted from a retracted position or a separate arm is inserted in between the lifting mechanism and the table top. 
     The second positon would be moving the table top down so that the table top is arranged in an inclined position, whereby exposing the lower face (underside) of the table to make cleaning under the lifting table possible. Moving the table top so that cleaning can be performed in all the area.