Abstract:
A ferromagnetic spring transfer apparatus employs a movable magnet residing outside of an enclosed pathway, magnetically aligns and holds the ferromagnetic spring while pneumatic cylinders move the spring within the enclosed pathway to a position where another pneumatic cylinder ejects the spring from the enclosed pathway into an assembly location.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to the movement of ferromagnetic components, and more specifically to an apparatus and method for handling and aligning a plurality of coiled springs in an automated assembly process. 
     Metallic coil springs are common components in countless devices. With many of these devices being mass produced, an automated device for the installation of these springs would reduce the installation time, minimize human error and reduce the assembly costs. However, two major problems have stood in the way of the automation of this task. 
     First, since springs are usually key components in the movement and operation of a mechanical device, precise alignment within the device is critical. Second, because of the wound nature of springs, adjacent springs brought into close proximity often tangle and require manual separation. For these two reasons, currently many assembly jobs that require spring insertions are performed by hand using manual labor. 
     Current automated component transfer systems use several different mechanisms in combination to grab, pick up, retain, transfer, align and release a spring in order to get the spring from its origin to its final resting place. The added complexity of using numerous mechanisms increases the likelihood of breakdown and narrows the adaptability of the systems for differing components, differing travel paths and different component orientations. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, an improved ferromagnetic component transfer system is provided for moving and precisely positioning coil springs in a tangle free manner. 
     Accordingly, it is an object of the present invention to provide an improved component transfer system for plural ferromagnetic components requiring transfer from an initial position to a precisely aligned final position. 
     It is a further object of the present invention to provide an improved system for transferring and aligning plural ferromagnetic components that are prone to tangling with other similarly situated components during the transfer process. 
     It is yet another object of the present invention to provide an improved transfer system for quickly, and reliably transferring and aligning ferromagnetic components in an assembly process without human touch. 
     It is still a further object of the present invention to provide a transfer device that does not require the mechanical coupling and uncoupling of the component from the component transfer device, and which, with minor modifications, can serve in various component assembly machines and processes. 
     It is yet another object of the invention to provide an improved device for transferring springs in an automated manner during an assembly process, from a supply side to an assembly side. 
     Another object of the invention is to re-orient and supply springs, one at a time, in an assembly environment. 
     The subject matter of the present invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. However, both the organization and method of operation, together with further advantages and objects thereof, may best be understood by reference to the following description taken in connection with accompanying drawings wherein like reference characters refer to like elements. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top, front perspective view of the preferred embodiment of the ferromagnetic component transfer device; 
     FIG. 2 is a bottom, rear perspective view of the preferred embodiment of the ferromagnetic component transfer device; 
     FIG. 3 is an exploded view of the preferred embodiment of the ferromagnetic component transfer device according to the present invention; and 
     FIG. 4 is a flow chart of the steps performed in the operation of the transfer device. 
    
    
     DETAILED DESCRIPTION 
     The system according to the invention moves ferromagnetic articles in an assembly or packaging system from one station to another. In a preferred embodiment, the system comprises an enclosed transfer path and a movable magnetic field generating device located outside of the enclosed transfer path that uses magnetic attraction to transfer and align ferromagnetic springs within the transfer path thereby maneuvering the springs into a position for installation in a device. 
     Referring now to FIG. 1, a top front perspective view of the preferred embodiment of the ferromagnetic component transfer device  10 , a transfer block  12  is provided, suitably comprising a section of non-magnetic material, defining the central body structure of the device. A non-metallic separation plate  14  is mounted to a first face of the body, and a side plate  16  is mounted to a second face of the body, suitably secured by bolts  18 . A spring supply tube  20  is received by plate  14 , defining a spring supply path into the interior of the transfer block  12 , as discussed hereinbelow. The spring supply tube  20  is clear, hollow and cylindrical and rests normally on the separation plate. Plural springs  22  are received into the tube  20 , in end to end fashion, suitably moving in the direction of arrow  24  during operation. 
     A linear bearing guide  26  is bolted to front face  30  on transfer block  12 , an arm  32  being provided for additional support and alignment. 
     A linear bearing channel  28  is slidingly attached to the linear bearing guide so as to form a linear bearing. An l-shaped transfer magnet bracket  34  is attached to the linear bearing channel  28  and oriented such that the bracket&#39;s longitudinal axis is perpendicular to the channel&#39;s longitudinal axis. A pneumatic cylinder  36  is carried by the bracket at an end distal from the point of mounting to the bearing channel, and a transfer magnet array  38  is carried at one end of the cylinder, suitably the end closest to the transfer block  12 . A bumper bracket  40  is affixed to the plate  16 , extending outwardly beyond the body of the transfer block, supporting an adjustable bumper arm  42 . A bumper member  44  is suitably attached to one end of the bumper arm. Bumper arm  42  is threadingly engaged with a hole  46  (FIG. 3) in the bracket and is secured in place with jam nut  48 . A spring exit or delivery port  50  extends through the side plate  16  at a lower corner thereof. 
     Bolted perpendicularly onto the face of the transfer block carrying the linear bearings, and located below the bearings is a support plate  52 . The support plate carries a double acting pneumatic transfer cylinder  54 , which is cooperatively engaged with bracket  34 . 
     Referring now to FIG. 2, a bottom rear perspective view of the preferred embodiment of the ferromagnetic component transfer device, arm  32  bolts to the back side face of the transfer block and carries spring separation cylinder  56  thereon. The spring separation cylinder is suitably a double acting pneumatic cylinder that projects into a slide recess  58  inside the body of transfer block  12 . A slide block  60 , which carries spring containment cylinder  62 , is operatively attached to the spring separation cylinder  56 . 
     A transfer cylinder mounting plate  64  is bolted to the transfer block  12 , somewhat below the location of  32 , and supports a pneumatic delivery cylinder  66  thereon. Cylinder  66  is suitably aligned with the delivery port  50  (not visible in FIG.  2 ). Also positioned in the transfer block  12 , beneath the position of the delivery port, set back slightly from the edge of the body, is a delivery magnet  68 , mounted in an exterior recess  70  in the transfer body. 
     In operation of the device, the springs  22  are received via supply tube  20  in the direction of arrow  24 , and exit the transfer block  12  at delivery port  50 . 
     To understand how this is accomplished, reference will now be made to FIG. 3, which is an exploded view of the ferromagnetic component transfer device, together with FIG.  1  and FIG.  2 . It will be noted that the transfer block  12  has a transfer groove  72  defined therein extending downwardly approximately half the height of the block  12 , and which is further in communication with a delivery groove  74  which is cut at an angle and terminates in a position corresponding to the position of delivery port  50 . At the opposite side of the block  12 , delivery cylinder  66  drives arm  76  inwardly and outwardly in the direction of arrow  78 . A spring engaging piston  80  is carried on the outermost end of the arm and projects through a hole in the mounting plate and the transfer block so as to move in the delivery groove  74 . It will be noted that each of the respective cylinders carry arm portions thereon, whereby actuation of the cylinders causes the arms to extend or retract. The arm of cylinder  56  is engaged with slide  60 , wherein operation of cylinder  56  causes slide  60  to move in the direction of arrow  84  along slide rails  86  defined within the transfer block. The slide rails cooperate with corresponding shoulder portions  88  on the slide  60 . Since cylinder  62  is secured to the slide  60 , it will move with movement of the slide. The arm of cylinder  62  is extensible up through an opening  90  in the slide. 
     In operation, springs  22  are fed into supply tube  14  and exit via delivery port  50 . The initial configuration of the various cylinders are as follows: The arm of spring containment cylinder  62  is extended, spring separation cylinder  56  has its arm retracted, the arm of magnet cylinder  54  is retracted, as are the arms of the transfer cylinder  66  and the delivery cylinder  36 . 
     Supply tube  20  is filled with substantially similar ferrometallic coil springs  22  positioned end to end to form a column such that the longitudinal axes of the springs are aligned with the longitudinal axis of the supply tube. A constant delivery stream of springs is fed through the center of the supply tube into the transfer groove. Since the supply tube is preferably made of a lightweight clear material such as LEXAN, visual inspection is allowed. Gravity acts upon the spring column such that the lead spring travels to the supply outlet end  82  of the tube and the center of the spring drops over the extended spring containment cylinder  62  arm until the spring&#39;s leading edge contacts the transfer block, stopping in transfer groove  72 . 
     With the lead spring contained by spring containment cylinder  62 , the spring separation cylinder  56  is extended pushing slide block  60  away from cylinder  56  (perpendicular to the longitudinal axis of the spring as it rests on the containment cylinder arm). The spring containment cylinder traverses along the transfer groove, maintaining the orientation of the lead spring within the groove  72 . This sideways movement removes the spring from alignment with the spring column and transfers it partially along groove  72 . After the spring separation cylinder  56  has reached the extent of its movement, the spring containment cylinder  62  retracts, freeing the separated lead spring which remains within transfer groove  72 . Spring separation cylinder  56  now retracts, moving slide block  60  back to its original position. The spring containment cylinder  62  again extends and projects into the center of the next spring that is waiting at the end of the supply tube, preventing any premature movement of the next spring within transfer groove  72 . 
     At this point magnet cylinder  36  is extended to push transfer magnet array  38  into close proximity to with separation plate  14 . The magnetic field of the transfer magnet array penetrates separation plate  14  reaching the spring. Due to the coiled configuration of the ferromagnetic spring, upon introduction of the magnetic field from transfer magnet array  38 , a hall effect is induced in the spring developing a magnetic field perpendicular to the longitudinal axis of the spring causing the spring to change its physical orientation in response to the attractive forces of the transfer magnet array. The spring turns, such that the longitudinal axis of the spring shifts 90 degrees within transfer groove  72  and the spring is pulled into contact with the inside face of separation plate  14 . 
     With the magnet cylinder  36  still extended, the transfer cylinder  56  is now extended, forcing mounting block  92  and transfer magnet bracket  34  to slide with linear bearing channel  28  along linear bearing guide  26  in a horizontal direction (arrow  94  of FIG. 1) across the transfer block. This causes the reoriented spring to be magnetically pulled along the rear face of separation plate  14  in transfer groove  72  until magnet bracket  34  contacts bumper  44  and stops. The magnet cylinder retracts and moves transfer magnet array  38  away from close contact with the separation plate. This removes the magnetic field of transfer magnet array  38  from the spring, and the spring, in absence of the magnetic field, rolls by gravity into delivery groove  74  where it abuts the delivery groove bottom wall and is securely retained in this position by orientation magnet  68 . 
     The transfer cylinder is now retracted so as to pull mounting block  96  and magnet bracket  34  along the linear bearing guide, returning the transfer magnet bracket to the initial position. 
     Now, delivery cylinder  66 , which protrudes through an orifice in the transfer block into orientation groove  74 , is extended and piston  80  contacts the spring. The longitudinal axis of delivery cylinder arm  66  is aligned with the longitudinal axis of the spring and pushes the spring out of the transfer block through delivery port  50  in side plate  16  and into the spring&#39;s final resting position in an awaiting assembly  98  (illustrated in phantom). If desired by the particular application, the delivery cylinder  66  can continue to extend, to compress the spring. Now, with the spring in position (or further operations thereto being taken over by another process) delivery cylinder arm  66  retracts out of orientation groove  74  signaling the end of the transfer, orientation and delivery cycles. The process can now begin again with the next spring that is waiting on the spring containment cylinder  62 . 
     FIG. 4, a flow chart of the operational steps of the device, illustrates the cycle of operation. Initialization step  100  is performed when the device is first started, and as noted above, entails having the spring containment cylinder extended and the other cylinders retracted (spring separation, magnet cylinder, transfer cylinder and delivery cylinder). The supply tube is filled with ferromagnetic coil springs, and the lead spring in the tube is centered on the spring containment cylinder. Once the device is initialized, in operation, the spring separation cylinder is extended (step  102 ), the spring containment cylinder is retracted (step  104 ), the spring separation cylinder is retracted (step  106 ), the spring containment cylinder is extended (step  108 ) the magnet cylinder is extended (step  110 ), the transfer cylinder is extended (step  112 ), the magnet cylinder is retracted (step  114 ), the transfer cylinder is retracted (step  116 ), the delivery cylinder is extended (step  118 ) and the delivery cylinder is retracted (step  120 ). At this point, the spring has been moved from the supply tube through the device and to the delivery point. Operation continues by looping back to step  102  to start the cycle over again. 
     It should be noted that distance that the magnet cylinder arm positions the magnet array from the separation plate is adjustable, by loosening the jam nut on the cylinder and threading the cylinder inwardly or outwardly from its mounting bracket. The distance is determined by the magnetic field strength required inside of the guide block to attract the spring and subsequently later release the spring when the magnet array is moved away from the separation plate. In the preferred embodiment, a stacked array of toroidal permanent rare earth magnets comprise the magnet array  38 , magnetically maintained on a shaft of the magnet cylinder. The number of magnets in the transfer magnet array can be varied with the strength requirement of the particular configuration. There must be sufficient magnetic strength to penetrate through the separation plate and attract the lead spring. A magnetic backing plate may also be utilized to increase the directional magnetic field strength of the transfer magnet array and the orientation magnet, if desired. 
     The separation plate is suitably clear to allow visual inspection of the device and can quickly be removed in the event of a jam. The plate is also fabricated from non-magnetic material as the constant proximity to transfer magnet array  38  would eventually lead to the permanent magnetism of the separation plate. 
     The extent of movement of the linear slide is adjusted by movement of the bumper  44 , for fine tuning of operation of the device. With the bumper moved inwardly or outwardly, the end of travel of the linear slide can be fine tuned. 
     Although in accordance with the preferred embodiment, transfer, orientation and delivery of ferrometallic springs is accomplished, other assembly parts may be employed. The magnets used need not be of the permanent magnet type, for example. In an embodiment where an electromagnet is used, the magnetic field strength may be varied throughout the process. For example, a moderate strength magnetic field may be used initially orient the component with a higher strength field used when the component is being transported, and finally the weakest force used to release the component. 
     Similarly, although pneumatic cylinders are used in the preferred embodiment, hydraulic or electric cylinders as well as combinations with spring assisted cylinders may be used in alternate embodiments. 
     The transfer and deliver groove sizes and configurations are determined according to the size of the component and the particular final orientation that is desired. 
     In the preferred embodiment the supply tube and separation plate are made of LEXAN, the slide block and magnet carrying shaft are made of steel, while the transfer block, slide rails and most of the other parts are fabricated from aluminum. 
     While a preferred embodiment of the present invention has been shown and described, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the invention in its broader aspects. The appended claims are therefore intended to cover all such changes and modifications as fall within the true spirit and scope of the invention.