System and method for hemming vehicle sheet metal

Abstract

A vehicle sheet metal hemming system ( 20 ) and method for hemming vehicle sheet metal outer and inner members ( 24 and 26 ) to each other is performed by prehemming and final hemming operations at a single station in cooperation with robot apparatus ( 42 ). A drive mechanism ( 98 ) has a rotary actuator ( 100 ) that moves a tool table ( 78 ) vertically to move tool heads ( 80 ) between outer idle positions and inner use positions as well as moving prehem tools ( 82 ) and final hem tools ( 84 ) of the tool heads so as to perform both the prehemming and the final hemming operations.

1 . A vehicle sheet metal hemming system comprising: 
 a part supply for providing vehicle sheet metal outer and inner members;    a hemming machine for cyclically hemming a periphery of an outer member to a periphery of an associated inner member;    robot apparatus for cyclically transferring an outer member and an associated inner member from the part supply to the hemming machine;    the hemming machine including a base having a stationary part mount that receives outer and inner members to be hemmed to each other;    a tool table supported for vertical movement on the base and having a plurality of tool heads mounted thereon for movement relative to the table inwardly and outwardly with respect to the part mount on which the outer and inner members are mounted;    each tool head including a prehem tool mounted thereon for movement relative thereto between: an inner use position for preforming prehemming of the periphery of the outer member with respect to the periphery of the inner member, and an outer idle position spaced outwardly from the inner use position;    each tool head also including a final hem tool for completing the hemming of the periphery of the outer member to the periphery of the inner member;    a drive mechanism including a rotary actuator having an output that rotates 360 degrees to move the tool table vertically on the base from an upper start position downwardly through a hemming stroke to a lower position and then upwardly back to the upper start position in preparation for another cycle;    a first set of cam mechanisms for moving the tool heads from outer idle positions on the tool table to inner use positions during the initial downward movement of the tool table under the impetus of the rotary actuator such that continued downward movement of the tool table then moves the prehem tool of each tool head to perform the prehem of the periphery of the outer member to the periphery of the inner member; and    a second set of cam mechanisms for moving the prehem tools of the tool heads from their inner use positions to their outer idle positions upon farther downward movement of the tool table to permit the final hem tools to complete the hemming of the periphery of the outer member to the periphery of the inner member under the impetus of the rotary actuator as the tool table reaches the lower position.    
   
   
       2 . A vehicle sheet metal hemming system as is  claim 1  wherein the rotary actuator of the drive mechanism includes an electric motor drive, a clutch, and a gear reducer that drive the rotary output for moving the tool table between its upper start and lower positions.  
   
   
       3 . A vehicle sheet metal hemming system as is  claim 1  wherein the robot apparatus includes: a first robot for cyclically transferring outer members from the part supply to the part mount of the hemming machine, a second robot for cyclically transferring an inner member from the part supply to the part mount of the hemming machine after prior transfer of the associated outer member thereto, and the second robot subsequently delivering the hemmed outer and inner members from the hemming machine.  
   
   
       4 . A vehicle sheet metal hemming system as in  claim 3  further including locators that cooperate with the second robot to locate the inner member with respect to the part mount during the hemming.  
   
   
       5 . A vehicle sheet metal hemming system as is  claim 1  wherein the hemming machine includes four vertical guides that support the tool table for its vertical movement between the upper start position and the lower position, and two of the guides having upper connections to the tool table and lower connections to the output of the rotary actuator to provide vertical movement of the tool table under the operation of the rotary actuator.  
   
   
       6 . A vehicle sheet metal hemming system as is  claim 5  wherein the four vertical guides are spaced horizontally around the stationary part mount of the base at approximately 90 degrees from each other, the two vertical guides having the upper and lower connections being spaced from each other 180 degrees with the other two vertical guides therebetween, the output of the rotary actuator including a connection bar having opposite ends that include the lower connections to the two vertical guides that also have the upper connections to the tool table, and the connection bar having an intermediate portion extending between its opposite ends.  
   
   
       7 . A vehicle sheet metal hemming system as in  claim 6  wherein the two other vertical guides have upper ends including locators that cooperate with the robot apparatus to locate the inner member with respect to the part mount during the hemming operation.  
   
   
       8 . A vehicle sheet metal hemming system as is  claim 6  wherein the output of the rotary actuator also includes a rotatively driven eccentric link and a connection link having one end including a pivotal connection to the eccentric link and having another end including a pivotal connection to the intermediate portion of the connection bar between its lower connections to the two vertical guides that also have the upper connections to the tool table.  
   
   
       9 . A vehicle sheet metal hemming system as is  claim 6  wherein the output of the rotary actuator also includes a rotatively driven eccentric link and a connection link having one end including a pivotal connection to the eccentric link and having another end including a pivotal connection to the intermediate portion of the connection bar between its lower connections to the two vertical guides that also have upper connections to the tool table, and the rotary actuator including an electric motor drive, a clutch and a gear reducer that drive the eccentric link to move the tool table between its upper start and lower positions.  
   
   
       10 . A vehicle sheet metal hemming system as is  claim 5  wherein the four vertical guides are spaced horizontally around the stationary part mount of the base at approximately 90 degrees from each other, the two vertical guides having the upper and lower connections being spaced from each other 180 degrees with the other two vertical guides therebetween, and the tool table including four tool heads spaced at 90 degrees from each other between the four vertical guides in and alternating relationship.  
   
   
       11 . A vehicle sheet metal hemming system as is  claim 10  wherein the first set of cam mechanisms includes: four slotted cam members mounted on the base and respectively associated with the four tool heads, and four roller cam followers respectively mounted by the four tool heads and respectively moved by the four slotted cam members on the base to move the tool heads between the outer idle positions and the inner use positions during the vertical movement of the tool table under the impetus of the rotary actuator.  
   
   
       12 . A vehicle sheet metal hemming system as is  claim 10  wherein the second set of cam mechanisms includes: four roller cams mounted on the stationary part mount of the base, and four plate cam followers respectively mounted by the prehem tools of the four tool heads and respectively moved by the four roller cams on the stationary part mount of the base to move the prehem tools relative to the tool heads from the inner use positions to the outer idle positions after continued downward movement of the tool head subsequent to completion of the prehemming.  
   
   
       13 . A vehicle sheet metal hemming system as is  claim 12  wherein the four roller cams of the second set of cam mechanisms each includes two cam rollers spaced from each other such that the associated tool head moves therebetween, and the four plate cam followers of the second set of cam mechanisms each including two cam plates that are respectively moved by the associate two cam rollers on the stationary part mount of the base to provide the movement of the prehem tools relative to the tool heads from the inner use positions to the outer idle positions upon continued downward movement of the tool table subsequent to completion of the prehemming.  
   
   
       14 . A vehicle sheet metal hemming system as is  claim 10  wherein the first set of cam mechanisms includes: four slotted cam members mounted on the base and respectively associated with the four tool heads, and four roller cam followers respectively mounted by the four tool heads and respectively moved by the four slotted cam members on the base to move the tool heads between the outer idle positions and the inner use positions during the vertical movement of the tool table under the impetus of the rotary actuator; and wherein the second set of cam mechanisms includes: four roller cams mounted on the stationary part mount of the base, and four plate cam followers respectively mounted by the prehem tools of the four tool heads and respectively moved by the four roller cams on stationary part mount of the base to move the prehem tools relative to the tool heads from the inner use positions to the outer idle positions after continued downward movement of the tool table subsequent to completing the prehemming.  
   
   
       15 . A vehicle fuel door sheet metal hemming system comprising: 
 a part supply for providing vehicle sheet metal fuel door outer and inner members;    a hemming machine for cyclically hemming a periphery of a fuel door outer member to a periphery of an associated fuel door inner member;    robot apparatus for cyclically transferring a fuel door outer member and an associated fuel door inner member from the part supply to the hemming machine;    the hemming machine including a base having a stationary part mount that receives fuel door outer and inner members to be hemmed to each other;    a tool table supported for vertical movement on the base and having a plurality of tool heads mounted thereon for movement relative to the table inwardly and outwardly with respect to the part mount on which the fuel door outer and inner members are mounted;    each tool head including a prehem tool mounted thereon for movement relative thereto between: an inner use position for preforming prehemming of the periphery of the fuel door outer member with respect to the periphery of the fuel door inner member, and an outer idle position spaced outwardly from the inner use position;    each tool head also including a final hem tool for completing the hemming of the periphery of the fuel door outer member to the periphery of the fuel door inner member;    a drive mechanism including a rotary actuator having an output that rotates 360 degrees to move the tool table vertically on the base from an upper start position downwardly through a hemming stroke to a lower position and then upwardly back to the upper start position in preparation for another cycle;    a first set of cam mechanisms for moving the tool heads from outer idle positions on the tool table to inner use positions during the initial downward movement of the tool table under the impetus of the rotary actuator such that continued downward movement of the tool table then moves the prehem tool of each tool head to perform the prehem of the periphery of the fuel door outer member to the periphery of the fuel door inner member; and    a second set of cam mechanisms for moving the prehem tools of the tool heads from their inner use positions to their outer idle positions upon farther downward movement of the tool table to permit the final hem tools to complete the hemming of the periphery of the fuel door outer member to the periphery of the fuel door inner member under the impetus of the rotary actuator as the tool table reaches the lower position.    
   
   
       16 . A vehicle sheet metal hemming system comprising: 
 a part supply for providing vehicle sheet metal outer and inner members;    a hemming machine for cyclically hemming a periphery of an outer member to a periphery of an associated inner member, and the hemming machine including a base having a stationary part mount that receives outer and inner members to be hemmed to each other;    robot apparatus including: a first robot for cyclically transferring outer members from the part supply to the part mount of the hemming machine, a second robot for cyclically transferring an inner member from the part supply to the part mount of the hemming machine after prior transfer of the associated outer member thereto, and the second robot subsequently delivering the hemmed outer and inner members from the hemming machine;    the hemming machine including a tool table supported for vertical movement on the base and having a plurality of tool heads mounted thereon for movement relative to the table inwardly and outwardly with respect to the part mount on which the outer and inner members are mounted;    each tool head including a prehem tool mounted thereon for movement relative thereto between: an inner use position for preforming prehemming of the periphery of the outer member with respect to the periphery of the inner member, and an outer idle position spaced outwardly from the inner use position;    each tool head also including a final hem tools for completing the hemming of the periphery of the outer member to the periphery of the inner member;    a drive mechanism including a rotary actuator having an output and also including an electric motor, a clutch and a gear reducer that drive the rotary output 360 degrees to move the tool table vertically on the base from an upper start position downwardly through a hemming stroke to a lower position and then upwardly back to the upper start position in preparation for another cycle;    a first set of cam mechanisms for moving the tool heads from outer idle positions on the tool table to inner use positions during the initial downward movement of the tool table under the impetus of the rotary actuator such that continued downward movement of the tool table then moves the prehem tool of each tool head to perform the prehem of the periphery of the outer member to the periphery of the inner member; and    a second set of cam mechanisms for moving the prehem tools of the tool heads from their inner use positions to their outer idle positions upon farther downward movement of the tool table to permit the final hem tools to complete the hemming of the periphery of the outer member to the periphery of the inner member under the impetus of the rotary actuator as the tool table reaches the lower position.    
   
   
       17 . A vehicle sheet metal hemming system comprising: 
 a part supply for providing vehicle sheet metal outer and inner members;    a hemming machine for cyclically hemming a periphery of an outer member to a periphery of an associated inner member, and the hemming machine including a base having a stationary part mount that receives outer and inner members to be hemmed to each other;    robot apparatus including: a first robot for cyclically transferring outer members from the part supply to the part mount of the hemming machine, and a second robot for cyclically transferring an inner member from the part supply to the part mount of the hemming machine after prior transfer of the associated outer member thereto, and the second robot subsequently delivering the hemmed outer and inner members from the hemming machine;    the hemming machine including a tool table having a plurality of tool heads mounted thereon for movement relative to the table inwardly and outwardly with respect to the part mount on which the outer and inner members are mounted;    four vertical guides that support the tool table for vertical movement between an upper start position and a lower position, and two of the vertical guides having upper connections to the tool table;    each tool head including a prehem tool mounted thereon for movement relative thereto between: an inner use position for preforming prehemming of the periphery of the outer member with respect to the periphery of the inner member, and an outer idle position spaced outwardly from the inner use position;    each tool head also including a final hem tool for completing the hemming of the periphery of the outer member to the periphery of the inner member;    a drive mechanism including a rotary actuator having an output that rotates 360 degrees, and said two vertical guides having the upper connections to the tool table also having lower connections to the output of the rotary actuator to move the tool table vertically on the base from an upper start position downwardly through a hemming stroke to a lower position and then upwardly back to the upper start position in preparation for another cycle;    a first set of cam mechanisms for moving the tool heads from outer idle positions on the tool table to inner use positions during the initial downward movement of the tool table under the impetus of the rotary actuator such that continued downward movement of the tool table then moves the prehem tool of each tool head to perform the prehem of the periphery of the outer member to the periphery of the inner member; and    a second set of cam mechanisms for moving the prehem tools of the tool heads from their inner use positions to their outer idle positions upon farther downward movement of the tool table to permit the final hem tools to complete the hemming of the periphery of the outer member to the periphery of the inner member under the impetus of the rotary actuator as the tool table reaches the lower position.    
   
   
       18 . A vehicle sheet metal hemming system comprising: 
 a part supply for providing vehicle sheet metal outer and inner members;    a hemming machine for cyclically hemming a periphery of an outer member to a periphery of an associated inner member, and the hemming machine including a base having a stationary part mount that receives outer and inner members to be hemmed to each other;    robot apparatus including: a first robot for cyclically transferring outer members from the part supply to the part mount of the hemming machine, a second robot for cyclically transferring an inner member from the part supply to the part mount of the hemming machine after prior transfer of the associated outer member thereto, and the second robot subsequently delivering the hemmed outer and inner members from the hemming machine;    the hemming machine including a tool table having four tool heads mounted thereon for movement relative to the table inwardly and outwardly with respect to the part mount on which the outer and inner members are mounted;    four vertical guides that support the tool table for vertical movement between an upper start position and a lower position, the four tool heads being mounted between the four vertical guides in an alternating relationship, two of the vertical guides having upper connections to the tool table, and the other two vertical guides having upper locators that cooperate with the second robot to locate the inner member during the hemming operation;    each tool head including a prehem tool mounted thereon for movement relative thereto between: an inner use position for preforming prehemming of the periphery of the outer member with respect to the periphery of the inner member, and an outer idle position spaced outwardly from the inner use position;    each tool head also including a final hem tool for completing the hemming of the periphery of the outer member to the periphery of the inner member;    a drive mechanism including a rotary actuator having an output that rotates 360 degrees, an electric motor drive, a clutch and a gear reducer that drive the rotary output, the rotary output including a rotatively driven eccentric link and a connection link having opposite ends one of which is connected to the rotatively driven eccentric link, a connection bar having opposite ends and an intermediate portion connected to the other end of the connection link, and said two vertical guides having the upper connections to the tool table also having lower connections to the opposite ends of the connection bar to move the tool table vertically on the base from an upper start position downwardly through a hemming stroke to a lower position and then upwardly back to the upper start position in preparation for another cycle;    a first set of cam mechanisms each of which includes: four slotted cam members mounted on the base and respectively associated with the four tool heads, and four roller cam followers respectively mounted by the four tool heads and respectively moved by the four slotted cam members on the base to move the tool heads from outer idle positions on the tool table to inner use positions during the initial downward movement of the tool table under the impetus of the rotary actuator such that continued downward movement of the tool table then moves the prehem tool of each tool head to perform the prehem of the periphery of the outer member to the periphery of the inner member; and    a second set of cam mechanisms each of which includes: four roller cams mounted on the stationary part mount of the base, and four plate cam followers respectively mounted by the prehem tools of the four tool heads and respectively moved by the four roller cams on stationary part mount of the base to move the prehem tools relative to the tool heads from their inner use positions to their outer idle positions after continued downward movement of the tool head subsequent to completing the prehemming to permit the final hem tools to complete the hemming of the periphery of the outer member to the periphery of the inner member under the impetus of the rotary actuator as the tool table reaches the lower position.    
   
   
       19 . A method for hemming vehicle sheet metal comprising: 
 operating robot apparatus to cyclically transfer a vehicle sheet metal outer member and an associated vehicle sheet metal inner member from a part supply to a hemming machine that includes a base having a stationary part mount that receives outer and inner members to be hemmed to each other and that also includes a tool table supported for vertical movement on the base and having a plurality of tool heads mounted thereon for movement relative to the table inwardly and outwardly with respect to the part mount on which the outer and inner members are mounted; and    operating a drive mechanism including a rotary actuator having an output that rotates 360 degrees to move the tool table vertically on the base from an upper start position downwardly through a hemming stroke to a lower position and then upwardly back to the upper start position in preparation for another cycle, with a first set of cam mechanisms moving tool heads on the tool table from outer idle positions to inner use positions during the initial downward movement of the tool table under the impetus of the rotary actuator such that continued downward movement of the tool table then moves a prehem tool of each tool head to perform a prehem of the periphery of the outer member to the periphery of the inner member, and with a second set of cam mechanisms subsequently moving the prehem tools of the tool heads from inner use positions to outer idle positions upon farther downward movement of the tool table to permit final hem tools of the tool heads to complete the hemming of the periphery of the outer member to the periphery of the inner member under the impetus of the rotary actuator as the tool table reaches the lower position.    
   
   
       20 . A method for hemming vehicle sheet metal fuel door comprising: 
 operating robot apparatus to cyclically transfer a vehicle sheet metal fuel door outer member and an associated vehicle sheet metal fuel door inner member from a part supply to a hemming machine that includes a base having a stationary part mount that receives fuel door outer and inner members to be hemmed to each other and that also includes a tool table supported for vertical movement on the base and having a plurality of tool heads mounted thereon for movement relative to the table inwardly and outwardly with respect to the part mount on which the outer and inner members are mounted; and    operating a drive mechanism including a rotary actuator having an output that rotates 360 degrees to move the tool table vertically on the base from an upper start position downwardly through a hemming stroke to a lower position and then upwardly back to the upper start position in preparation for another cycle, with a first set of cam mechanisms moving tool heads on the tool table from outer idle positions to inner use positions during the initial downward movement of the tool table under the impetus of the rotary actuator such that continued downward movement of the tool table then moves a prehem tool of each tool head to perform a prehem of the periphery of the fuel door outer member to the periphery of the fuel door inner member, and with a second set of cam mechanisms subsequently moving the prehem tools of the tool heads from inner use positions to outer idle positions upon farther downward movement of the tool table to permit final hem tools of the tool heads to complete the hemming of the periphery of the fuel door outer member to the periphery of the fuel door inner member under the impetus of the rotary actuator as the tool table reaches the lower position.