Abstract:
A method of joining workpieces includes locating first ends of two first workpieces in a moveable part coupling portion. The lengths of the first workpieces are measured. Any difference in length between the first workpieces is determined. Two additional workpieces are located adjacent the first ends of the first workpieces based on the determined difference in length. The first workpieces are connected to the second workpieces.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to and benefit from U.S. Patent Application Ser. No. 61/822,671 filed on May 13, 2013 which is currently pending and fully incorporated by reference herein. 
     
    
     BACKGROUND 
       [0002]    It is well-known to attach a first workpiece to a second workpiece for various purposes. In one example, an end fitting is attached to a driveshaft tube, such as by welding. 
         [0003]    Continuing with the example, it is preferred that as many end fittings be attached to as many tubes as possible to achieve economies of scale and efficiency. Thus, if a method was known to simultaneously attach two end fittings to two tubes, a greater output of completed tubes could be realized. 
         [0004]    Previous attempts have been made to simultaneously attach two end fittings to two tubes, but the apparatus utilized in the process was problematic and did not result in satisfactory results. One disadvantageous result of the prior methods was that the tubes often did not have exactly the same length. Instead, tubes inserted into a machine might have slight variations in their length. The variations in length prevented the machine from properly positioning the welding apparatus for the first and second workpieces at the correct locations. The machine would generate an error and be unable to complete the welding step. 
         [0005]    In view of the problems of the known prior art devices, it would be advantageous for a machine to be able to simultaneously connect two first workpieces with two second workpieces, such as by welding, even when the first workpieces do not have the same length. 
       SUMMARY 
       [0006]    A method of joining workpieces includes securing first ends of two first workpieces in a device capable of selective axial movement. The length of each of the first workpieces is determined. The difference in length between the first two parts is determined. The axial location of both first parts is simultaneously adjusted to account for any differences in length. Two second workpieces are located adjacent the first ends of the first two workpieces. The first and second workpieces are simultaneous joined together. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0007]    Exemplary embodiments of the present disclosure will now be described by way of example with reference to the accompanying drawings, in which: 
           [0008]      FIG. 1  is a perspective view of two workpieces and a pedestal assembly; 
           [0009]      FIG. 2  is a perspective view of a portion of  FIG. 1 ; 
           [0010]      FIG. 3  is a top view of a welding apparatus in a first condition; 
           [0011]      FIG. 4  is a top view of the welding apparatus of  FIG. 3  in a second condition; and 
           [0012]      FIG. 5  is a top view of the welding apparatus of  FIG. 3  in a third condition. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0013]    It is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined herein. 
         [0014]    Hence, specific dimensions, directions or other physical characteristics relating to the embodiments disclosed are not to be considered as limiting, unless expressly stated otherwise. 
         [0015]      FIGS. 1-5  illustrate a welding apparatus according to an embodiment of the invention. The welding apparatus includes a first welding assembly  20 , a second welding assembly  22 , a hydraulic device  24 , a pedestal assembly  26 , and a controller  28 . The welding assemblies  20 ,  22 , the hydraulic device  24 , and the pedestal assembly  26  are disposed on and secured to a platform  30 ; however, it is understood that the components may be disposed and secured in any manner that allows an accurate geometric relationship to one another to be determined. Further, it is understood that the welding assemblies  20 ,  22 , the hydraulic device  24 , and the pedestal assembly  26  are typically disposed within an enclosure (not shown) commonly used in automated operations. The controller  28  is in communication with the first welding assembly  20 , the second welding assembly  22 , and the hydraulic device  24  as best seen in  FIGS. 3-5 . 
         [0016]    As shown in  FIGS. 3-5 , the first welding assembly  20  is disposed adjacent a first end of the platform  30  The first welding assembly  20  comprises a first clamping device  32 , a first welding device  34 , and at least one position sensor  36 . Each of the first clamping device  32 , the first welding device  34 , and the at least one position sensor  36  are in communication with the controller  28 . The first clamping device  32  is disposed intermediate a middle portion of the platform  30  and the first welding device  34 . 
         [0017]    The first clamping device  32  may be placed in an engaged position, a partially engaged position, and a disengaged position by the controller. In the engaged position, the first clamping device  32  closes, coupling a first part  38  thereto. In the partially engaged position, the first clamping device  32  is partially closed, to facilitate orienting the first part  38  along an axis of the first part  38  with respect to the first welding device  34 . In the disengaged position, the first clamping device  32  is open, and the first part  38  may be disposed into or removed from the first welding device  34 . 
         [0018]    The first welding device  34  performs a welding operation to couple the first part  38  to a second part  40 , as further described herein. The second part  40  is disposed against, or adjacent, the first part  38 ; however, it is understood that the second part  40  may be disposed within or about the first part  38 . When the first clamping device  32  is placed in the engaged position, the controller  28  may instruct the first welding device  34  to perform the welding operation. The first welding device  34  is a numerically controlled welding device, and a position of the first welding device  34  is controlled by the controller  28 . 
         [0019]    The first part  38  may be a driveshaft component, such as a driveshaft tube. The second part  40  may be a driveshaft tube end fitting. While examples of the first and second parts are provided, other parts are permissible. 
         [0020]    The at least one position sensor  36  forms a portion of the first welding assembly  20  and is in communication with the controller  28  to determine a position of at least one of the first part  38  and the second part  40  when the first clamping device  32  is placed in the engaged position or the partially engaged position. Information collected by the at least one position sensor  36  is transmitted to the controller  28  for use by the controller  28  in determining a position of the first welding device  34  and a second welding device  42 . It is understood that the first welding device  34  and the second welding device  42  operate in a symmetrical or “mirror image” manner about a reference plane passing through the middle portion of the platform  30  in response to instructions transmitted by the controller  28 . In other words, if the first welding device  34  moves in an axial direction by a predetermined distance, then the second welding device  42  moves in the same axial direction by the same distance. 
         [0021]    The second welding assembly  22  is disposed adjacent a second end of the platform  30 . The second welding assembly  22  comprises a second clamping device  44 , the second welding device  42 , and at least one position sensor  46 . Each of the second clamping device  44 , the second welding device  42 , and the at least one position sensor  46  are in communication with the controller  28 . The second clamping device  44  is disposed intermediate the middle portion of the platform  30  and the second welding device  42 . 
         [0022]    The second clamping device  44  may be placed in an engaged position, a partially engaged position, and a disengaged position by the controller  28 . In the engaged position, the second clamping device  44  closes, coupling a third part  48  of a predetermined size thereto. In the partially engaged position, the second clamping device  44  is partially closed, to facilitate orienting the third part  48  along an axis of the part  48  with respect to the second welding device  42 . In the disengaged position, the second clamping device  44  is open, and the third part  48  may be disposed into or removed from the second welding assembly  22 . 
         [0023]    The second welding device  42  performs a welding operation to couple the third part  48  to a fourth part  50 . The fourth part  50  is disposed against, or adjacent, the third part  48 ; however, it is understood that the fourth part  50  may be disposed within or about the third part  48 . 
         [0024]    When the second clamping device  44  is placed in the engaged position, the controller  28  may instruct the second welding device  42  to perform the welding operation. The second welding device  42  is a numerically controlled welding device, and a position of the second welding device  42  is controlled by the controller  28 . 
         [0025]    The third and fourth parts  48 ,  50  may be the same as the first and second parts  38 ,  40 , respectively, as discussed above. 
         [0026]    The at least one position sensor  46  forms a portion of the second welding assembly  22  and is in communication with the controller  28  to determine a position of at least one of the third part  48  and the fourth part  50  when the second clamping device  44  is placed in the engaged position or the partially engaged position. Information collected by the at least one position sensor  46  is transmitted to the controller  28  for use by the controller  28  in determining a position of the first welding device  34  and the second welding device  42 . As mentioned hereinabove, it is understood that the first welding device  34  and the second welding device  42  of the welding apparatus operate in a symmetrical or “mirror image” manner about the reference plane passing through the middle portion of the platform in response to instructions transmitted by the controller  28 . 
         [0027]    The hydraulic device  24  comprises at least a hydraulic pump  52 , a plurality of conduits  54 , and at least one actuation device. The hydraulic device  24  is in communication with the controller  28 , the first welding assembly  20  and the second welding assembly  22  to facilitate operation of the first welding assembly  20  and the second welding assembly  22  in response to instructions transmitted by the controller  28 . 
         [0028]    A first actuation device  56  is on the first welding device  34 , a second actuation device  58  is on the second welding device  42 , a third actuation device  60  is on the first clamping device  32  and a fourth actuation device  62  is on the second clamping device  44 . As a non-limiting example, the hydraulic device  24  may facilitate placing the first clamping device and the second clamping device in the engaged position, the partially engaged position, and the disengaged position. As a second non-limiting example, the hydraulic device may facilitate orienting or holding the first part  38  with respect to the second part  40  and the third part  48  with respect to the fourth part  50 , as described below. 
         [0029]    As shown in  FIG. 1 , the pedestal assembly  26  supports two first parts  38  and facilitates orienting each of the first parts  38  along the axis of each of the first parts  38  with respect to the first clamping device  32  and the second clamping device  44 . The pedestal assembly  26  comprises a support portion  64 , a slide device  66 , and a part coupling portion  68 . The pedestal assembly  26  is disposed on the middle portion of the platform  30 . 
         [0030]    The support portion  64  may have any shape capable of rigidly supporting the slide device  66  and the part coupling portion  68 . The support portion  64  is preferably formed from a metal; however, it is understood that the support portion  64  may be formed from any rigid material. A lower portion  70  of the support portion  64  is securely coupled to the platform  30 . An upper portion  72  of the support portion  64  is coupled to the slide device  66 . 
         [0031]    The slide device  66  facilitates movement of the part coupling portion  68  along the axis of the first part  38  and the third part  48  with respect to the support portion  64  and the first clamping device  32 , and the second clamping device  44 . In other words, the clamping portion  32 ,  44  and the first part  38  and third part  48  are axially fixed with respect to each other but move together with respect to the slide device  66 . The slide device  66  comprises a first plate  74 , a pair of linear bearings  76 , a second plate  78 , and at least one axial restraint device  80 , as shown in  FIG. 2   
         [0032]    The first plate  74  may be such as a substantially rectangular shaped member rigidly coupled to the upper portion  72  of the support portion  64 ; however, it is understood that the first plate  74  may have any other shape. The first plate  74  is preferably formed from a metal; however, it is understood that the first plate  74  may be formed from any rigid material. A portion of each of the linear bearings  76  is rigidly coupled to the first plate  74 . 
         [0033]    Each of the linear bearings  76  is a linear bearing as known in the art. The linear bearings  76  facilitate movement of the second plate  78  along the axis of the first part  38  and third part  48  with respect to the first plate  74 . A second portion of each of the linear bearings  76  is rigidly coupled to the second plate  78 . 
         [0034]    The second plate  78  may be such as a substantially rectangular shaped member rigidly coupled to the part coupling portion  68 ; however, it is understood that the second plate  78  may have any other shape. The second plate  78  is preferably formed from a metal; however, it is understood that the second plate  78  may be formed from any rigid material. 
         [0035]    As shown in  FIGS. 1 and 2 , preferably there are two axial restraint devices  80  that may be coupled to the first plate  74  and/or the second plate  78  to limit movement of the second plate  78  along the axis of the first part  38  and the third part  48 . Each of the axial restraint devices  80  may comprise a portion biased with a spring  82 . The portion biased with the spring  82  militates against a sudden stop that the axial restraint device  80  may cause when the second plate  78 , moving along the axis of the first part  38  and third part  48  reaches a terminal position. The spring  82  resists a force trying to move the plate  78  to a terminal position and biases the plate  78  back to a neutral position. 
         [0036]    The part coupling portion  68  is rigidly coupled to the second plate  78 . The part coupling portion  68  is preferably formed from a metal; however, it is understood that the part coupling portion  68  may be formed from any rigid material. The part coupling portion  68  includes a first holding portion  84  and a second holding portion  86 , which are opposingly oriented on the part coupling portion  68 . Each of the first holding portion  84  and the second holding portion  86  holds a first end portion  88  of the first part  38  and a first end portion  88 ′ of the third part  48 . 
         [0037]    In use, the controller  28  allows a welding operation to be performed by the first welding device  34  and the second welding device  42  when the first part  38  and the third part  48 , which may have different lengths, are disposed in the welding apparatus described herein. The slide device  66  allows a position of the first part  38  and the third part  48 , disposed in the part coupling portion  68  to be axially adjusted to facilitate welding operations. More particularly, the slide device  66  permits the first part  38  and the third part  48  to be welded to the second part  40  and fourth part  50  even when the first and third parts  38 ,  48  are not equal length. Variability of length may be common among the first part and third parts  38 ,  48 , and the slide device  66  facilitates accurately positioning the first part  38  and the third part  48 , so that axial length difference between a second end portion  90 ,  90 ′ (disposed adjacent the welding devices, respectively) of the first part  38  and the third part  48  and each of the welding devices  34 ,  42  during the welding operation is minimal. 
         [0038]    To perform the welding operation, the first end portions  88 ,  88 ′ of first part  38  and the third part  48  are placed into the part coupling portion  68  of the pedestal assembly  26  and the second end portions  90 ,  90 ′ are placed adjacent the first clamping device  32  and the second clamping device  44 , respectively. Next, the second part  40  is disposed adjacent the first part  38 , and the fourth part  50  is disposed adjacent the third part  48 . It is understood that the first welding device  34  and the second welding device  42  or another portion of the welding apparatus is configured to position the second and fourth parts  40 ,  50  with respect the first part  38  and the third part  48 . By way of example, the second part and fourth parts  40 ,  50  may be located with the first and second welding devices  34 ,  42 . The welding devices  34 ,  42  are located with the first activation device  56  and the second activation device  58 . The first and second welding devices  34 ,  42  may be configured to selectively hold the second part and fourth parts  40 ,  50 . Then, an operator of the welding apparatus commands the controller  28  to begin the welding operation. 
         [0039]    The welding operation comprises a part measuring process and a welding process. The part measuring process is performed before the welding process to measure and record axial deviation of the first and third parts  38 ,  48 . In other words, the part measuring process measures differences in axial length between the first and third parts  38 ,  48 . 
         [0040]    Once commanded by the operator, the first clamping device  32  and the second clamping device  44  are placed in the partially engaged position about the first end portions  88 ,  88 ′ of the first part  38  and the second part  48  to substantially orient the axes of each of the parts  38 ,  48  along an axis the welding apparatus. The third actuation device  60  and the fourth actuation device  62  are engaged and are used to put the clamping devices  32 ,  44  in the partially engaged position. After the first clamping device  32  and the second clamping device  44  are placed in the partially engaged position, the first welding device  34  and the second welding device  42  apply a force to the second and fourth parts  40 ,  50  using the hydraulic device  24 . The force applied using the hydraulic device  40  urges each of the second and fourth parts  40 ,  50  against the second end portion  90 ,  90 ′ of the first and third parts  38 ,  48 , respectively. The second and fourth parts  40 ,  50  contact the first and third parts  38 ,  48 , and applies a force thereto. The force applied to the first and third parts  38 ,  48  by the second and fourth parts  40 ,  50  causes the first and third parts  38 ,  48 , the part coupling portion  68 , and a portion of the slide device  66  to move with respect to a remaining portion of the slide device  66  and the support portion  64 . More particularly, the second plate  78  moves with respect to the first plate  74  as a result of the force. 
         [0041]    The force applied by the hydraulic device  40  equalizes between the first and third parts  38 ,  48 , resulting in an axial shift of the first and third parts  38 ,  48 , and thus the part coupling portion  68 , away from one of the welding devices  34 ,  42  toward the other welding device  34 ,  42  to compensate for any differences in length of the parts  38 ,  48 . More particularly, the second plate  78  moves away from one of the welding devices  34 ,  42  toward the other welding device  34 ,  42 . 
         [0042]    Once a predetermined amount of force has been applied, the at least one position sensor  36 ,  46  determines a position of at least one of the second end portions  90 ,  90 ′ of the parts  38 ,  48 . Following this step, pressure applied by the hydraulic device  24  may be relieved and the welding devices  34 ,  42  may be backed away from the second end portions  90 ,  90 ′ of the parts  38 ,  48 . 
         [0043]    Information collected by the position sensors is transmitted to the controller  28  to instruct the welding devices  34 ,  42  in performing the welding process. Specifically, the information collected by the position sensors  36 ,  46  is used to determine positions of the welding devices  34 ,  42  during the welding process. Next, the first clamping device  32  and the second clamping device  42  are placed in the partially engaged position to substantially orient the axes of each of parts  38 ,  48  along an axis the welding apparatus has been configured for. After the first clamping device  32  and the second clamping device  44  are placed in the partially engaged position, the first welding device  34  and the second welding device  42  move to a position determined by the controller  28  based on the information collected by the position sensors  36 ,  46 . Then, the position sensors  36 ,  46  determine a position of at least one of the second end portions  90 ,  90 ′ of the first part  38  and the third part  48  to confirm that the position of the second end portion  90 ,  90 ′ matches the information collected by the position sensors  34 ,  36  during the first part measuring process. Upon confirmation that the length difference between the parts  38 ,  48 , if any, is taken into account, the first clamping device  32  and the second clamping device  44  are placed in the engaged position, coupling the parts  38 ,  48  to the clamping devices  32 ,  44 , respectively. The third and fourth activation devices  60 ,  62  are engaged to put the clamping devices  32 ,  44  in the engaged position. In one embodiment, the foregoing may involve that the parts  38 ,  48  and the part coupling portions  68  are asymmetrically located with respect to the welding devices  34 ,  42 . 
         [0044]    Next, the first welding device  34  and the second welding device  42  weld the first and third parts  38 ,  48  to the second and fourth parts  40 ,  50 . Upon completion of the welding process, the first clamping device  32  and the second clamping device  44  are placed in the disengaged position and the welding devices are backed away, allowing the operator of the welding apparatus to remove each of the first parts (now including the second parts welded thereto) from the welding apparatus. 
         [0045]    In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiments. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.