Abstract:
A packaging arrangement for smoothly and conveniently providing small hardware items to an assembly line operator wherein the hardware items are fastened onto a flexible band in line in the order in which they are to be installed on an article being assembled. The flexible band is divided into equal segments as defined by index marks or holes punched into the band. The items are fastened to the band using securing features fashioned from the band itself in a manner and orientation by which each one can be plucked from the band with a tool that can grasp an item, pull it off the band, transport it to the article being assembled, and install it on the article without intermediate disengagement from the tool. The arrangement and utilization of the band improves the productivity and reliability of a manual assembly of mechanical devices such as hard disk drives and other read/write devices. The dispensing package consisting of the loaded flexible band is prepared off-line and, depending on the number of items required by the assembly, may either be rolled up or fastened onto a rigid frame, The package is then loaded, either in a cartridge or individually into a cabinet wherein the sequential sections are presented to the line operator, one segment at a time.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     (1) Field of the Invention  
         [0002]     The invention relates to processes for the assembly line manufacture of articles and more particularly to the timely and orderly delivery of a plurality of small hardware components during the assembly of complex articles containing mechanical components.  
         [0003]     (2) Background of the Invention and Description of Previous Art  
         [0004]     It is well known that the productivity of an assembly line is strongly dependent on the timely and orderly delivery of components of the article being manufactured to the appropriate various stations of the assembly line. Complex articles containing electronic and mechanical components, such as computer storage disk drives, compact disc drives and the like, have additional assembly requirements, which include high degrees of cleanliness, ambient control, and careful handling of components.  
         [0005]     Computer drives of all sorts typically consist of a mechanical drive mechanism to which at least one printed circuit board is attached and electrically connected. In the manufacture of these drives, the printed circuit board is typically populated with electronic components, on a placement machine which uses robotic arms to pick, place, and solder the components. Placement machines have a very high and flawless placement rate. On the other hand, the mechanical sub-assemblies to which printed circuit boards are connected, still require manual assembly by a line operator. The mechanical sub-assemblies utilize a plurality of small hardware parts such as screws, nuts, pins, gears, springs, micro switches, bearings, and the like which must be selected, oriented and then placed by an operator in a specified sequence. Finally, the mechanical sub assembly and corresponding printed circuit board(s) are manually assembled and mounted on a chassis and encased. These manual assembly operations are highly operator dependent and greatly limit productivity and reliability yield of the finished product. While limited volume and multiple part number considerations do not make total robotic assembly cost effective, it is nevertheless desirable to streamline the process by reducing the time spent by the operator in selecting, sequencing, and orienting the small hardware components on the assembly line. The present invention provides a method for accomplishing such a procedure and thereby improves the overall productivity as well as the reliability of the finished product.  
         [0006]     For the purpose of the present invention small hardware is defined as mechanical components which individually weigh less than about 200 grams and have a longest dimension of less than about 10 cm. Articles fitting this definition include but are not limited to pins, gears, springs, studs, spacers, micro switches, nuts, bolts, screws, and bearings. Further, for the purpose of present invention, the definition of small hardware also excludes articles which are spherically shaped and which, being totally symmetric, do not require orientation for installation.  
         [0007]     Conventionally, small hardware is packed randomly and arbitrarily in bags, boxes, or trays. The operator must first pick up a piece of hardware, by hand, determine its orientation, either visually or by feel, then orient it for installation, and finally install it on the assembly. These operations are not only time consuming but are also stressful to the operator, both physically and mentally, particularly under pressure of time. Further, hardware items packed loosely tend to rub against each other in handling, thereby not only causing damage to the item but also creating particulate debris, which in highly critical clean conditions, can seriously affect the reliability of the final product. The method and means of presentation of small hardware to the assembly line operator described by the present invention specifically addresses these issues and not only streamlines the manual assembly but also eases the burden on the line operator. Further, the method of the invention brings the small hardware installation a step closer to an automated process with minimal additional cost. This is due mainly to the ability to prepare the parts for presentation off-line.  
         [0008]     Ames, U.S. Pat. No. 5,887,727 cites a method and means for sorting and funneling small hardware by the use of screens which are manually operated. The screens can be designed to parallel align and transport cylindrical objects such as pins or springs. However, an additional operation may be required to align screws with all the heads in one direction. Labat, et. al., U.S. Pat. No. 6,158,585 shows a dispenser of screws to an assembly line wherein a set of small hardware, notably of screws, all of the same type and size, is packaged on a holder consisting of a thin compartmented card having a lower break-away foil and covered with a transparent plastic layer in the form of a blister pack. Each holder is labeled and multiple holders, all consisting of the same screw, are prepared, and loaded into a cartridge which, in turn is loaded into a dispensing cabinet off-line. The holders are then manually extracted on-line, one at a time, through an opening in the bottom of the cabinet. If more than one type of screw is used, each screw type is packaged in its own cartridge and cabinet. Thus each dispensing cabinet, provided to the line assembler, contains only one type of screw.  
       SUMMARY OF THE INVENTION  
       [0009]     It is an object of this invention to provide a packaging arrangement for smoothly and conveniently providing small hardware items to an assembly line operator.  
         [0010]     It is another object of this invention to provide for improving the productivity and reliability of a manually operated mechanical assembly station.  
         [0011]     It is yet another object of this invention to describe a packaging arrangement and manner of fastening small hardware items to a package substrate so that they may be easily and conveniently withdrawn from the packaging substrate oriented in a direction to be directly installed on an article being assembled by an assembly line operator without requiring any additional orientation by the operator.  
         [0012]     These objects are accomplished by arranging small hardware parts on a dispensing substrate which consists of a flexible material such as a plastic, paper, or a smooth fibrous material. The parts are fastened onto the dispensing substrate in indexed sections and arranged in the order in which they will be installed on the article being assembled. Each of the parts are fastened onto the dispensing substrate in a manner so that they can be withdrawn from the substrate by the assembler, either by hand or preferably with a hand tool, grasping the part so that it is immediately oriented, in the hand or tool, towards the installation point. The dispensing package is prepared off-line and, depending on the number of items required by the assembly, may either be rolled up or fastened onto a rigid frame, The package is then loaded, either in a cartridge or individually into a cabinet wherein the sequential sections are presented to the line operator, one segment at a time.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  is a top view of a segment of a flexible strip for holding small hardware arranged in a sequence and oriented for rapid, efficient, and reliable dispensing of and manual installation said hardware by an assembly line operator.  
         [0014]      FIG. 2  is a top view of a flexible presentation strip, prepared according to the teaching of this invention, containing small hardware for assembly of a fixed disk magnetic data storage device wherein the pieces are arranged in indexed sections sequenced in the order of assembly and fastened to the strip in a manner that they can be withdrawn from the strip oriented toward installation on the article being assembled.  
         [0015]      FIG. 3  through  FIG. 7  are isometric drawings illustrating the assembly of a fixed disk drive magnetic data storage device using the indexed small hardware dispensing package described by the present invention.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0016]     In a first embodiment of this invention an indexed flexible small parts dispensing strip is described. The strip is indexed by punched holes or marks at constant intervals preferably near the long edge of the strip. The segments of the strip between two successive index holes or marks are fitted with retainment features which firmly hold a piece of small hardware on the strip. The position of piece of small hardware is held in an orientation on the strip in a direction that when presented to an assembly operator can be picked off the strip either by hand or with an appropriate tool, can be carried by the operator directly to its location on a unit being assembled without any further orientation by the operator.  
         [0017]     Referring to  FIG. 1 , there is shown a section  10 ′ of a flexible strip  10  fitted with index holes  12 , spaced at equal intervals along one edge of the strip  10 . The flexible strip  10  is preferably made of a, plastic material, for example, Mylar®, polyethylene, or polypropylene. Mylar® is a registered trademark of the E.I. duPont de Nemours Company. The index holes  12 , as shown, are round and are formed by a hole punch. Alternately, the index holes may have another shape, for example square or rectangular. The index holes  12  may alternatively also consist of marks on the strip which can be read by a mechanism which advances the strip  10  to present a particular segment to the assembly operator. Alternately the holes or marks may be located in the center the strip  10  or on both sides of the strip  10 . The region between two adjacent index holes/marks defines a segment of the strip. The small hardware items are mounted onto the segments of the strip in the order in which they will be picked and applied to an article being assembled by the online assembler. The hardware items are mounted onto the dispensing strip  10  by an offline operator. Each segment may presented only during the assembly and may contain only one type and size of hardware, but may contain more than one of that particular size and type, for example several screws of the same type and size which are successively installed to fasten a unit to the assembly.  
         [0018]     On the left side of the strip section  10 ′ there is shown a feature  14   a  for the retainment of a screw. Screws are, by far, the most widely used small hardware item. The diameter of the punched circular hole  14   a  is just slightly smaller than the major diameter of the thread of the screw which is to be presented. The hole  14   a  is provided by at least two and preferably three or four relieves  16 , which are slots cut preferably radially and evenly spaces around the hole  14   a . The relieves  16  allow a screw (not shown) to be easily inserted and removed from the hole  14   a , and firmly hold the screw in place during storage and handling of the strip  10 . A Phillips head screw  18  is shown mounted on the strip  10  in the hole adjacent to hole  14   b . To remove the screw  18  the operator inserts a crew retrieval tool, for example a screw holding (grasping) screwdriver and withdraws the screw  18 , either by first pressing the screw through the strip  10  and then withdrawing the screw or by directly withdrawing the screw  18  from the strip  10 . Feature  14   b  is simply an opening for a larger screw.  
         [0019]      FIG. 14   c  is a circular opening for holding a threaded or non-threaded stud. There are no relieves around this opening. Instead the opening  14   c  is made slightly large than the diameter of the stud shaft. A stud  22  is shown loaded in the adjacent opening. The stud  22  is inserted from the top while the two tabs  20  are spread apart from underneath and then released to hold the stud in place. The toughness and resiliency of Mylar® make it particularly well suited as a flexible substrate material when applied to form tabs. The stud  22  is withdrawn by the assembly operator by grasping the head, either with a tool or by hand, and pulling the stud away. Once withdrawn the stud  22  is oriented directly on the tool for mounting on the article being assembled.  
         [0020]     Washers, spacers, bearings, gears, covers, and other circular and essentially flat items can be mounted on the strip  10  by using two, three, or four tabs  20 . In  FIG. 1 a  washer  24  is held by three tabs  20  and can be withdrawn by the online assembler in the same manner as the stud  22 , preferably by using a grasping tool or tweezers. Oftentimes it will be necessary to install a screw with washer combination onto an article. To facilitate this, the strip  10  is provided with an opening  21  (dashed circle) beneath the washer. The desired screw is first withdrawn from the strip, using a grasping tool. Then the screw is inserted through the washer  24  and opening  21  on the strip, the washer  24  is then grasped with the tool and the screw/washer combination is withdrawn from the strip. Mounting the screw/washer combination on the assembly article is again conducted with a smooth motion of delivery and placement since the item is already correctly positioned on the grasping tool for installation on the article.  
         [0021]     Pins, and other straight items can by secured on the strip  10  using opposing tabs  20  each with a small punched hole  26 . A pin  28  is shown in place in such a mounting. The pin  28  is withdrawn from the strip  10  by grasping one end of the pin  28  and pulling it off while lifting the tabs  20  up to free the pin. After the pin  28  is withdrawn, it is already in the proper grasping position to install it directly onto the assembly article.  
         [0022]     All of the hardware items mentioned so far have been fastened to the flexible strip  10  by cutting, punching, or slitting the strip. Other small items which such as microswitches, springs, and other types of fasteners, may be best coupled to the strip  10  by clips fastened to the strip or by affixing certain compartments to the strip. The strip itself, providing it is not too long, may be supported by a frame, thereby making it tray-like. Further, in order to reduce the length of the strip, multiple items, such as small screws or washers, may be grouped into a single index segment. This would be the case, where a number of the same type of screw is used to fasten a cover onto the assembly. However, having more than one type or size of a component in the same index segment is dangerous and not recommended.  
         [0023]     In a second embodiment of this invention, an article is assembled using small harware supplied on a flexible stripe of the type described in the first embodiment. A hard disk data storage device will be assembled. All of the small hardware components will be provided on an indexed component strip having only eleven index segments. In addition to the hardware components, three sub-assemblies, namely the disk motor and spindle, the head sub-assembly, and a magnet sub-assembly are provided at the assembly station. A mounting chassis, a device populated printed circuit board with a plastic shield, and a top cover are also provided.  
         [0024]     Referring to  FIG. 2 , a top view of the populated small hardware dispensing strip  30  is shown. The strip  30  is preferably made of a plastic material, for example, Mylar®, polyethylene, or polypropylene. Twelve round index holes  32  are formed by a hole punch, defining eleven indexed component sections. Each segment is between about 5 and 8 cm. wide making the total length of the dispensing strip between about 55 and 90 cm. The dispensing strip  30  is between about 6 and 8 cm. wide. Alternately, the index holes may have another shape, for example square or rectangular. The index holes  32  may alternatively also consist of marks on the strip which can be read by a mechanism which advances the strip  30  to present a particular interval to the assembly operator. Alternately the holes or marks may be located on both sides of the strip  30 . The hardware dispensing strip may be mounted on a frame or may be rolled up and placed in a presentation cabinet (not shown) wherein it will be presented one segment at a time to the assembler through an access opening on the top of the cabinet.  
         [0025]     There are five types of screws (C 1 , C 6 , C 9 , C 10 , and C 11 ) in the embodiment, all of which are mounted in round holes slightly smaller in diameter than the major diameter of the respective screw thread. Each screw hole has four relieves  34  formed by cutting four radial slots  36  at each hole as outlined in the first embodiment. Each screw is picked by the assembler, preferably using a grasping type screwdriver. Thereby after extraction from the strip  30  each screw will be automatically be oriented for installation onto the assembly. The other items on the strip  30  consist of washers, spacers, a disk clamp, and a threaded stud. These items are secured on the hardware dispensing strip  30  by two or three tabs  38  cut into the strip as described in the first embodiment.  
         [0026]     The items held on the dispensing strip  30  are also shown in isometric view directly below their position on the strip  30 . Also illustrated in  FIG. 2  are the three mechanical sub-assemblies which are provided separately to the operator at the assembly station. They are 1) a disk drive motor  40  and spindle  42  assembly  44 ; 2) a read/write head assembly  46  with bearing unit  48 , coil  50 , and wiring strap  52  with connector  54 ; and 3) a magnet sub-assembly  56  with mounting holes  58 . Three magnetic storage disks  60  are also provided separately.  
         [0027]     Referring now to  FIG. 3 , there is shown an isometric view of a chassis or base plate onto which a fixed disk magnetic storage device will be assembled. The chassis  100  is provided with openings which will be identified as the components are installed. The disk drive motor  40  and spindle  42  sub-assembly  44  is first installed into the recessed opening  70  and secured by screw C 1  and washer C 2  in hole  72 . The operator first places the unit  44  into the recess  70 , then withdraws the screw C 1  from the first segment of the dispensing strip  30  preferably using a grasping screw driver. Then the screw C 1  is inserted through the washer C 2  and strip opening  31 . The washer C 2  is then grasped with the tool and the screw/washer combination is withdrawn from the strip  30 , and driven home into the base of the assembly  44 . When the screw/washer C 1 /C 2  combination has been withdrawn from the hardware dispensing strip  30 , it is already oriented towards the assembly point.  
         [0028]     Referring, now to  FIG. 4 , the first storage disk  60  is picked and placed onto the spindle  42 , preferably using a three prong pickup tool. The first spaced C 3  is then pulled off the dispensing strip  30  and placed onto the spindle  42  using a similar three prong tool. A second disk  60  is then placed onto the spindle  42 , followed by the placement of the second spacer C 4  and a third disk  60 . The disk clamp C 5  is next withdrawn from the dispensing strip  30  using a tweezers or pickup tool and placed on the spindle  42  and fastened using the six screws C 6  which are successively plucked from the dispensing strip  30  with a grasping screwdriver and immediately driven home into the threaded holes  43  in the top of the spindle  42  completing the assembly and placement of the disk drive sub-assembly  45 .  
         [0029]     Referring now to  FIG. 5 , the read/write head sub-assembly  46  is positioned in opening  74  (see  FIG. 3 ) of the base plate  100 , The threaded stud C 7  is next withdrawn from the dispensing strip  30 , preferably using a grasping screwdriver, pulling it straight out, pushing it through the washer C 8  on the strip, then grasping the washer C 8  with the tool, and withdrawing both stud C 7  and washer C 8  from the strip. The stud and washer are then inserted into the opening  74  from below the chassis  100  and driven home into the bearing unit  48  of the head sub-assembly  46 . The wiring harness  52  is then dressed over the base plate  100  and the end connector  54  fastened onto the base plate  100  in the recess  78 .  
         [0030]     Referring now to  FIG. 6  the magnet sub-assembly  56  is fastened to the base plate  100  with the two long screws C 9  which are pulled, one at a time, from the dispensing strip  30 , preferably with a grasping screwdriver, passed through openings  58  on the magnet sub-assembly, and driven into the threaded openings  76  (see  FIG. 3 ). Again, the screws C 9  are pulled from the dispensing strip  30  and driven home without the need of any additional orientation movements on the part of the assembler. This completes the assembly of the mechanical functions of the hard disk drive. Referring to  FIG. 7 , a cover  102  is next placed over the entire assembly and fastened with the six screws C 10 . In a final step, a populated printed circuit board (not shown) is next mounted onto the underside of the base plate  100  using the final 4 screws C 11 . The printed circuit board is then connected to the head connector  54  completing the assembly of the hard disk magnetic storage unit  104 .  
         [0031]     While this invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the invention.