Patent Publication Number: US-2009230706-A1

Title: Mechanical device for gripping the inside of hollow or bored bodies

Description:
FIELD OF THE INVENTION  
     This invention concerns a device for gripping the inside of hollow or bored items in order to move and handle them during operation, treatment or assembly phases. 
     STATE OF THE ART  
     Expanding/contractible devices, such as the so called finger gripper, which can have pneumatic control, are available for gripping the inside of hollow or bored bodies or items which however cannot be gripped on the outside. However, due to their configuration and the fact that they are subject to intense wear, they are not suitable and efficient when the bodies or items to be handled are particularly heavy and the cavity or bore has uneven or grooved surfaces and said bodies or items need to be reliably sustained. 
     OBJECTS AND SUMMARY OF THE INVENTION  
     One of the objects of this invention is to propose a purely mechanical device suitable to effectively facilitate the inside gripping of hollow bodies or items and to sustain them safely even if they are heavy and with uneven or grooved internal surfaces. 
     Another object of the invention is to provide a device which is simple and economic to make, practical and easy to control and use, substantially without wear and which when used can also be hung on a means of suspension, a chain conveyer or a similar translating device. 
     Said objects and implicit advantages deriving from them are achieved, according to the invention, with a gripper device that comprises a prehensile member with a supporting head, forming an axial seat and able to take on a contracted inactive position and an active expanded position; a divaricator mounted in said axial seat and moving between a first and a second positions to respectively define the contracted and expanded positions of said prehensile member; and a control lever fulcrated on said supporting head and connected to the divaricator to provoke the movements of the latter, from the first position, in which the prehensile member is in the inactive position, to the second position, in which the prehensile member is in the active position. 
     The prehensile member and the relative supporting head are made of a metal material and preferably form an integral part. 
     In turn, the prehensile member has a number of flexible sectors each provided, internally, with a conical portion with which the divaricator interacts to cause its contraction and expansion and, externally, with a lug to engage with the internal surface of the body or item preferably on a level with a groove or undercut thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
       The invention will, however, be illustrated in greater detail in the following description made in reference to the attached drawings, in which: 
         FIG. 1  is an exploded view of the components of the device; 
         FIG. 2  is a view in perspective of the assembled device in an inactive position; 
         FIGS. 3 and 4  respectively are a side view and a cross section view of the device in the inactive position in  FIG. 2 ; 
         FIG. 5  is a view in perspective of the assembled device in the active position; and 
         FIGS. 6 and 7  respectively are a side view and a cross-section of the device in the active position as in  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     As shown, the gripper device basically comprises a prehensile member  11 , a divaricator  12  and a control lever  13 . 
     The prehensile member  11  is made of a metal material and a supporting head  14  with which it forms a single piece and delimits an axial seat  15 . The supporting head  14  has a base which defines an annular supporting plane  16  facing towards the prehensile member, around the latter. 
     The prehensile member  11  is basically cylindrical and has longitudinal cuts  17  to divide it into several flexible sectors  18 , which can move radially between a contracted inactive position and an expanded active one. Each of said flexible sectors  18  is provided internally, near its free end, with a protrusion  19  with an initial conical bevelled portion  20  and, externally with a lug  21  also with a bevel  22 . 
     The movements of the flexible sectors  18  from one position to another are caused by the divaricator  12 , which is connected and movable axially by means of the control lever  13 . The divaricator  12  is housed in the axial seat  15  of the prehensile member  11  and can be moved between a first position, in which it is retracted and distant from the internal protrusions  19  of the flexible sectors  18  of the prehensile member and a second position, in which it is forwarded and its end engages with said internal protrusions  19 . 
     The control lever  13  is fulcrated with a pivot  23  to the supporting head  14  and has a slot  24  in which a pin  25  extends and slides, connecting the lever to the divaricator  12 . In this way, the angular movements of the lever  13  correspond to the axial movements of the divaricator  12  between the first position and the second position defined above. 
     On the other hand, the supporting head  14  of the prehensile member  11  can be provided with bores  26  or various other types of connections for attaching the device and any type of suspension element, chain, conveyer or the like for its handy use and smooth handling according to requirements. 
     The flexible sectors  18  of the prehensile device  11  are arranged and loaded elastically to be and to remain normally in the contracted position when the divaricator  12  is the retracted position as shown in  FIGS. 2-4 . In this condition, the prehensile member  11  can be inserted each time, as far as the supporting plane  16  at the base of the supporting head  14 , in a cavity or a bore of the body or item—not shown—to be gripped, handled, suspended and/or moved. Then the prehensile member  11  can be activated by using the control lever  13  in the direction to move the divaricator  12  forward so as to engage the internal protrusions  19  of the flexible sectors  18  and to expand in this way the prehensile member as shown in  FIGS. 5-7 . Therefore, the external lugs  21  of the flexible sectors  18  will engage tightly and block on the internal surface of the cavity or bore in which the prehensile member has been inserted. To support the suspension of the body or item besides the gripping process, the cavity or the bore can be provided with or have an internal groove in which to insert the external lugs  21  of the prehensile member  11 . 
     Furthermore, when the divaricator  12  is moved forward and engages with the internal protrusions  19  to determine the expansion of the flexible sectors of the prehensile member, it is impossible to retract it unless the control lever is intentionally used, thus ensuring the efficiency of the device. 
     However it can also be made possible for the lever to be stopped and restrained in its operation position of the prehensile member. For this purpose, the control lever  13  can be provided on one side with a cavity  27  and, on the supporting head  14  of the prehensile member  11  can be mounted a spring stop  28  designed to engage in said cavity, to stabilize the position of the lever when the latter is turned in the expansion position of the prehensile member.