Patent Publication Number: US-7224251-B2

Title: Magnetic retaining device for machine tool

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a magnetic retaining or grasping device, and more particularly to a magnetic retaining or grasping device for stably grasping or holding or retaining work pieces to machines or machine tools, and for allowing the work pieces to be effectively worked or machined by the machines or machine tools. 
   2. Description of the Prior Art 
   Typical machines or machine tools may comprise one or more clamping vices or other retaining or grasping devices for grasping or holding or retaining work pieces to the machines or machine tools, and for allowing the work pieces to be worked or machined by the machines or machine tools. 
   However, it is required to thread and to unthread a number of fasteners, to clamp or secure the work pieces to the machines or machine tools, such that it is difficult and it may take a long time to secure and to disengage the work pieces from the machines or machine tools. 
   The other typical machines or machine tools may comprise one or more magnetic retaining or grasping devices for magnetically grasping or holding or retaining the work pieces to the machines or machine tools. 
   However, the typical magnetic retaining or grasping devices comprise one or more magnetic members secured together in series that may not be used to firmly attach or secure the work pieces to the machines or machine tools, such that the work pieces may be easily moved relative to the machines or machine tools and may not be effectively worked or machined by the machines or machine tools. 
   The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional magnetic retaining or grasping devices. 
   SUMMARY OF THE INVENTION 
   The primary objective of the present invention is to provide a magnetic retaining or grasping device for stably grasping or holding or retaining work pieces to machines or machine tools, and for allowing the work pieces to be effectively worked or machined by the machines or machine tools. 
   In accordance with one aspect of the invention, there is provided a magnetic retaining device for attaching a work piece to a machine tool, the magnetic retaining device comprising a magnetic housing including a first and a second housing members secured together and spaced away from each other, and having different magnetic poles, the magnetic housing including a chamber formed therein, and a magnetic core rotatably received in the chamber of the magnetic housing, and including a first and a second core members having different magnetic poles, and the magnetic poles of the first and the second core members of the magnetic core being the same as that of the first and the second housing members of the magnetic housing. A magnetic force of the first and the second housing members of the magnetic housing may be offset by the first and the second core members of the magnetic core when the first and the second core members of the magnetic core are received in the second and the first housing members of the magnetic housing respectively, and may be increased when the first and the second core members of the magnetic core are received in the first and the second housing members of the magnetic housing respectively, in order to solidly or stably attract or secure or retain or grasp the work piece to the machine tool, and to allow the work piece to be effectively worked or machined by the tool members of the machine tool. 
   The magnetic core includes at least one spacer disposed between the first and the second core members, to space the first and the second core members away from each other. The magnetic core may further include at least one magnetic member disposed between the first and the second core members, to allow the magnetic fields or magnetic fluxes to be transmitted through the magnetic member or transmitted between the first and the second core members. 
   The magnetic core may further include at least one end plate secured to the first and the second core members, to secure the first and the second core members together. 
   The magnetic housing includes at least one end cap secured to the first and the second housing members, to stably or to solidly secure the first and the second housing members together, the end plate includes a pin extended therefrom and engageable with the end cap, to limit the magnetic core to rotate relative to the magnetic housing. 
   For example, the end cap of the magnetic housing includes a passage formed therein, to slidably receive the pin of the end plate. The passage of the end cap of the magnetic housing may include a semi-circular shape. The end plate includes a shank extended therefrom and extendible out through the end cap of the magnetic housing. 
   A second magnetic retaining device may further be provided and may include a magnetic core rotatably received in a magnetic housing and having a shank extended out of the magnetic housing, and a socket coupled to the shanks of the magnetic retaining device and the second magnetic retaining device, to allow the magnetic cores of the two magnetic retaining device to be rotated in concert with each other. 
   The magnetic housing includes at least one beam secured thereto, to protect and to reinforce the magnetic housing, and to prevent the magnetic housing from being damaged or scraped by the work piece or other objects. 
   The magnetic housing may further include at least one spacer disposed between the first and the second housing members, and may further include at least one magnetic member disposed between the first and the second housing members, to allow the magnetic fields or magnetic fluxes to be transmitted through the magnetic member or transmitted between the first and the second housing members. 
   The magnetic housing includes at least one fastener securing the first and the second housing members together. For example, the magnetic housing includes a spacer through which the fastener is engaged. 
   Each of the first and the second housing members of the magnetic housing includes a lower portion having a notch formed therein, to decrease a bottom surface of the lower portion thereof, and to increase a magnetic force or a magnetic strength of an upper portion of each of the housing members of the magnetic housing, in order to firmly or stably support or secure the work piece to the machine tool. 
   One or more brackets may further be provided to secure the magnetic housing to the machine tool, the bracket may be engaged into the notch of the magnetic housing, to stably secure the magnetic housing to the machine tool. Each of the first and the second housing members of the magnetic housing may further include an upper portion having a harder peg engaged therein, to reinforce the upper portion of the magnetic housing. 
   The magnetic housing includes at least one table secured on the first and the second housing members, for engaging with the work piece and for preventing the magnetic housing from being damaged or scraped by the work piece or other objects. A base panel may further be provided and secured to the magnetic housing, for separating the magnetic housing from the machine tool and for preventing magnetic fields or magnetic fluxes from being transmitted through the base panel, or transmitted between the magnetic housing and the machine tool. 
   Further objectives and advantages of the present invention will become apparent from a careful reading of the detailed description provided hereinbelow, with appropriate reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a plan schematic view illustrating an attachment of a magnetic retaining or grasping device in accordance with the present invention to a machine or machine tool; 
       FIG. 2  is a cross sectional view taken along lines  2 — 2  of  FIG. 1 ; 
       FIG. 3  is an exploded view of the magnetic retaining or grasping device; 
       FIG. 4  is a perspective view of the magnetic retaining or grasping device; 
       FIG. 5  is a cross sectional view taken along lines  5 — 5  of  FIG. 4 ; 
       FIG. 6  is a cross sectional view taken along lines  6 — 6  of  FIG. 4 ; 
       FIG. 7  is a cross sectional view similar to  FIG. 5 , illustrating the operation of the magnetic retaining or grasping device; 
       FIGS. 8 ,  9 ,  10  are plan schematic views similar to  FIG. 1 , illustrating the attachment of the magnetic retaining or grasping device in accordance with the present invention to the other machines or machine tools; 
       FIG. 11  is a partial cross sectional view of the magnetic retaining or grasping device as shown in  FIGS. 9 and 10 ; and 
       FIGS. 12 ,  13  are partial top plan schematic views illustrating the attachments of a number of magnetic retaining or grasping devices in accordance with the present invention to the machines or machine tools. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to the drawings, and initially to  FIGS. 1 and 2 , a magnetic retaining or grasping device  1  in accordance with the present invention comprises a base panel  10  for securing to a machine or machine tool  90 , such as to one or more channels  91  of the machine or machine tool  90  with one or more brackets  11  and one or more fasteners  12 . 
   For example, as shown in  FIGS. 1–2  and  8 , the magnetic retaining or grasping device  1  may be used to firmly or stably support one or more work pieces  93  horizontally on the machine or machine tool  90 , for allowing the work pieces  93  to be effectively worked or machined by the drilling tools  94  ( FIGS. 1–2 ), the milling tools  95  ( FIG. 8 ), or the like of the machine or machine tool  90 . 
   Alternatively, as shown in  FIGS. 9–11 , the magnetic retaining or grasping device  1  may also be used to firmly or stably support one or more work pieces  93  vertically on the machine or machine tool  90 , for allowing the work pieces  93  to be effectively worked or machined by the drilling tool  94  ( FIG. 9 ), the milling tool  95  ( FIG. 10 , or the like of the machine or machine tool  90 . 
   The base panel  10  includes one or more holes  13  formed therein ( FIG. 3 ) for receiving fasteners  14  which may be used to secure a magnetic housing  2  on top of the base panel  10 . The base panel  10 , the brackets  11 , and the fasteners  12 ,  14  are preferably made of non-magnetic materials, such as stainless steel materials, aluminum materials, copper materials, or the like, to separate or to isolate the magnetic housing  2  from the machine or machine tool  90  and to prevent the magnetic housing  2  from magnetic loss to the machine or machine tool  90 . 
   As shown in  FIGS. 2–6 , the magnetic housing  2  of the magnetic retaining or grasping device  1  may include two housing members  20 ,  21  which may be secured together and which may be spaced away from each other, and the two housing members  20 ,  21  include different magnetic poles, such as N-pole and S-pole respectively, best shown in  FIGS. 2 ,  5  and  7 . 
   The magnetic housing  2  includes a circular or cylindrical chamber  22  formed therein. For example, each of the two housing members  20 ,  21  includes a semi-circular or semi-cylindrical recess  22  formed therein, to form or define the circular or cylindrical chamber  22  of the magnetic housing  2 . The two housing members  20 ,  21  are made of magnetic materials, such as low carbon soft metal materials. 
   Each of the two housing members  20 ,  21  includes a flat and vertical surface  23  formed in inner portion of the lower portion  24  thereof, and another flat and vertical surface  26  formed in inner portion of the upper portion  27  thereof; and includes a cut notch  25  formed in outer portion of the lower portion  24  thereof, to decrease the bottom surface of the lower portion  24  thereof, and thus to allow the upper portion  27  thereof to have greater magnetic forces or strengths. The brackets  11  may be engaged into the cut notches  25  of the housing members  20 ,  21 . 
   One or more spacers  28 ,  29  may be disposed or engaged between the lower portion  24  and the upper portion  27  of the housing members  20 ,  21  respectively, and offset from the circular or cylindrical chamber  22  of the magnetic housing  2 , to suitably the housing members  20 ,  21  away from each other. The housing members  20 ,  21  may be solidly secured together with fasteners  30  which may be engaged through spacers  31 . 
   One or more, such as two end caps  32 ,  33  may further be provided and engaged or secured onto the ends of the magnetic housing  2  or of the housing members  20 ,  21  respectively, to further solidly secure the housing members  20 ,  21  together. One of the end caps  33  includes a semi-circular passage  34  formed therein ( FIGS. 3 ,  6 ). 
   The magnetic housing  2  or the housing members  20 ,  21  are made of magnetic materials, such as low carbon soft metal materials, and will thus be easily scraped or damaged by the work pieces  93  or other objects. For protecting the magnetic housing  2  or the housing members  20 ,  21 , one or more beams  35  of greater hardness may further be provided and secured onto the outer peripheral portion of the magnetic housing  2  or of the housing members  20 ,  21 , to protect and to reinforce the magnetic housing  2  or the housing members  20 ,  21 . 
   It is preferable that each of the housing members  20 ,  21  of the magnetic housing  2  further includes one or more cavities  36  formed in the upper portion  27  thereof, each for receiving a peg  37  therein. The pegs  37  also include a greater hardness than that of the magnetic housing  2  or of the housing members  20 ,  21 , to protect and to prevent the upper portion  27  of the housing members  20 ,  21  from being scraped or damaged by other objects. 
   The spacers  28 ,  29 ,  31 , the fasteners  30 , the end caps  32 ,  33 , the beams  35 , and the pegs  37  are also preferably made of non-magnetic materials. Each of the housing members  20 ,  21  of the magnetic housing  2  further includes one or more screw holes  38  formed in the upper portion  27  thereof ( FIG. 3 ), for threading with fasteners  39  which may be used to secure one or more face boards or tables  40  on top of the magnetic housing  2  or of the housing members  20 ,  21 . 
   The tables  40  are also made of magnetic materials for attracting or retaining or grasping the work pieces  93  to the magnetic housing  2  of the magnetic retaining or grasping device  1  ( FIGS. 1–2  and  9 – 10 ). One or more magnetic or permanent magnetic members  41  may further be provided and disposed between the flat surfaces  23  of the housing members  20 ,  21 , and retained in place by the housing members  20 ,  21  and the base panel  10  and the fasteners  30  and the spacer  28  ( FIGS. 2 ,  5 ,  7 ). 
   The magnetic retaining or grasping device  1  further includes a magnetic core  50  rotatably received in the circular or cylindrical chamber  22  of the magnetic housing  2 , and having one or more, such as two core members  51 ,  52  which may be secured together by non-magnetic end plates  53  and fasteners  54 , and which may be spaced away from each other by one or more spacers  57 , and the two core members  51 ,  52  include different magnetic poles, such as S-pole and N-pole respectively, best shown in  FIGS. 2 ,  5  and  7 , for acting with the magnetic poles of the housing members  20 ,  21  respectively. 
   Each of the end plates  53  includes a shank  55  extended therefrom, and outwardly extended through the end caps  32 ,  33  of the magnetic housing  2 , for allowing the magnetic core  50  to be rotated or driven by driving tools (not shown) or the like. One or more washers  56  may be attached to the shanks  55  and engaged with the housing members  20 ,  21  and the end caps  32 ,  33  of the magnetic housing  2 . One of the end plates  53  includes a pin  58  extended therefrom ( FIGS. 3 ,  6 ), and slidably engaged in the semi-circular passage  34  of the end cap  33 , to limit the magnetic core  50  to rotate relative to the magnetic housing  2 . 
   For example, when the pin  58  is engaged in one end of the semi-circular passage  34  of the end cap  33 , the core members  51 ,  52  may be rotated and received in the semi-circular or semi-cylindrical recesses  22  of the two housing members  20 ,  21  respectively ( FIG. 5 ); and the core members  51 ,  52  may be rotated and received in the other semi-circular or semi-cylindrical recesses  22  of the other housing members  21 ,  20  respectively ( FIGS. 2 ,  7 ) when the pin  58  is engaged in the other end of the semi-circular passage  34  of the end cap  33 . 
   It is also preferable that the end plates  53 , the fasteners  54 , the shanks  55 , the washers  56 , the spacers  57 , and the pin  58  are made of non-magnetic materials, such as stainless steel materials, aluminum materials, copper materials, or the like, to prevent the magnetic forces or magnetic fields of the core members  51 ,  52  of the magnetic core  50  from being interfered by these elements. 
   The magnetic core  50  may further include one or more magnetic or permanent magnetic members  59  provided and disposed between the core members  51 ,  52 , and retained in place by the core members  51 ,  52  and the spacer  57 , to allow magnetic fields or magnetic fluxes to be effectively transmitted through the magnetic members  59  or to be effectively transmitted between the core members  51 ,  52 . 
   In operation, as shown in  FIG. 5 , when the core members  51 ,  52  are received in the semi-circular or semi-cylindrical recesses  22  of the two housing members  20 ,  21  respectively, the opposite magnetic poles of the two core members  51 ,  52  may be attracted or acted with the magnetic poles of the housing members  20 ,  21  respectively, to offset or decrease the magnetic force of the core members  51 ,  52  and the housing members  20 ,  21 , such that the work piece  93  may not be attracted to the magnetic retaining or grasping device  1 . 
   On the contrary, as shown in  FIGS. 2 and 7 , when the core members  51 ,  52  are rotated and received in the semi-circular or semi-cylindrical recesses  22  of the other housing members  21 ,  20  respectively, the magnetic poles of the two core members  51 ,  52  may be aligned with and acted with the same magnetic poles of the housing members  20 ,  21  respectively, to combine the magnetic forces of the core members  51 ,  52  and the housing members  20 ,  21  together, and thus to provide a great magnetic attracting or sucking force to stably attract or secure the work piece  93  to the magnetic retaining or grasping device  1 . 
   Referring next to  FIGS. 12 and 13 , two or more magnetic retaining or grasping devices  1  may be attached or secured onto the machine or machine tool  90  with the brackets  11  and the fasteners  12 . In addition, the shanks  55  of the magnetic cores  50  of two different magnetic retaining or grasping devices  1  may be coupled or secured together with couplers, sockets  60  or the like, for allowing the magnetic cores  50  to be rotated relative to the magnetic housings  2  respectively, in order to attract or retain a number of work pieces  93  or one or more greater work pieces  93  to the machine or machine tool  90  with the magnetic retaining or grasping devices  1 . 
   Accordingly, the magnetic retaining or grasping device in accordance with the present invention may be used for stably attracting or grasping or holding or retaining or attaching the work pieces to the machines or to the machine tools, and for allowing the work pieces to be effectively worked or machined by the tool members of the machines or the machine tools. 
   Although this invention has been described with a certain degree of particularity, it is to be understood that the present disclosure has been made by way of example only and that numerous changes in the detailed construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.