Abstract:
A mechanical indexing device. The device comprises a mechanism for converting linear motion into many different combinations of linear and rotary motion, whereby an object can be moved along a desired linear path and indexed through a desired arc of rotation.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to the field of mechanisms. More specifically, the invention comprises a mechanism for converting linear motion into a combination of linear and rotary motion, whereby an object can be moved along a desired linear path and indexed through a desired arc of rotation.  
           [0003]    2. Description of the Related Art  
           [0004]    Numerous prior art devices are designed to convert rotary motion into linear motion. U.S. Pat. No. 1,016,611 to Chilton (1912) discloses a bottle filling and capping machine. This machine is comprised of a rotating carousel. A mechanism (see FIG. 10) converts the rotating motion into linear motion for the bottles. Thus, as the carousel turns, the bottles are moved up and down to the appropriate positions for the capping process.  
           [0005]    A similar approach is taken in U.S. Pat. No. 2,517,592 to Nordquist (1950). A camming surface (designated as “68” in FIG. 1) is used to raise and lower jars as they move on a rotating carousel. U.S. Pat. No. 2,638,259 to Garrett (1953) uses a similar camming surface (see FIG. 1).  
           [0006]    More camming surfaces capable of converting rotary motion to linear motion are disclosed in U.S. Pat. No. 3,139,914 to Bingham (1961) and U.S. Pat. No. 3,335,767 to Manas (1967). Like the Chilton, Nordquist, and Garrett devices, the Bingham and Manas devices convert the machine&#39;s primary rotary motion into a reciprocating linear motion. All these devices—Chilton, Nordquist, Garrett, Bingham, and Manas—convert continuous rotary motion into rotary motion with an added reciprocating linear motion. It is significant to note that the rotary motion is always present in these devices; i.e., they are incapable of producing a purely linear motion at any point.  
           [0007]    A different approach is disclosed in U.S. Pat. No. 4,027,767 to Gluck (1977). The Gluck device uses a slotted cylinder with a following peg riding in the slot in order to produce reciprocating linear motion (See FIG. 1). The Gluck device also uses a 6 position indexing gear (element “17” in FIG. 3) to index a turntable (“19”) through several set indexing points. Thus, the device (which is actually a combination of several mechanisms) is capable of indexing a turntable to a fixed position, moving it up and down, then indexing it to another position. In other words, it can have purely linear or rotary motion at a given point. Unfortunately, the Gluck device is rather complex—employing several mechanisms to achieve the desired linear and rotary motion.  
           [0008]    Some devices are, of course, capable of converting a primarily linear motion into rotary motion. One such device is disclosed in U.S. Pat. No. 5,806,404 to Sher (1998). The Sher device uses a reciprocating piston as the driving mechanism (such as found in a pneumatic driving system). A pair of pegs riding in a groove convert this reciprocating linear motion to a continuous rotary motion (see FIGS. 2, 3, and  5 ). The actual object being moved (a cutter head) simultaneously exhibits rotary and linear motion; i.e., the device is incapable of producing purely linear or rotary motion.  
           [0009]    Accordingly, the prior art devices are limited in that they: (1) Are incapable of producing purely linear motion; and/or (2) Require a complex combination of several mechanisms to achieve linear motion without rotary motion.  
         BRIEF SUMMARY OF THE INVENTION  
         [0010]    It is desirable to index a table through a fixed arc, and to then move the table up and down in a purely linear fashion. This type of motion is useful in many processes, particularly where one wishes to bring a polar array of objects into contact with another stationary object so that some operation can be performed.  
           [0011]    The present invention seeks to create this type of motion using only the reciprocating linear motion of an air cylinder as the driving force. Referring to FIG. 1, air cylinder  12  is affixed to base  10 . Air cylinder  12  has cylinder rod  14 , which moves up and down as air pressure is applied to port  16  (typically by an air hose—not shown). Table  18  is attached to the upper end of cylinder rod  14 . FIG. 1 shows table  18  in its lowered position.  
           [0012]    Turning now to FIG. 2, air pressure has been applied to air cylinder  12 , with the result that table  18  has been lifted to its upper position. This movement—between FIG. 1 and FIG. 2—constitutes the linear input motion which drives the device. To lower table  18 , the air pressure is shut off to air cylinder  12 . Gravity then pulls table  18  back down to its lowered position.  
           [0013]    Turning to FIG. 3, the reader will observe that table  18  has several pegs  20  spaced evenly around its perimeter. Indexer  26  is positioned close by the perimeter of table  18 . Indexer  26  has slot  38  cut completely through its thickness. Pegs  20  are sized to fit within slot  38 . Slot  38  is designed to convert a portion of the aforementioned linear motion into an indexing rotary motion—as will be explained in more detail subsequently.  
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is an isometric view, showing the proposed invention.  
         [0015]    [0015]FIG. 2 is an isometric view, showing the table in its raised position.  
         [0016]    [0016]FIG. 3 is an isometric view, showing the indexer.  
         [0017]    [0017]FIG. 4 is an isometric view, showing more details of the indexer.  
         [0018]    [0018]FIG. 5 is an isometric view, showing the table in its lowered position.  
         [0019]    [0019]FIG. 6 is an isometric view, showing the table as it begins to rise, and its interaction with the indexer.  
         [0020]    [0020]FIG. 7 is an isometric view, showing the table as it continues to rise, and its interaction with the indexer.  
         [0021]    [0021]FIG. 8 is an isometric view, showing the table as it reaches its apex, and its interaction with the indexer.  
         [0022]    [0022]FIG. 9 is an isometric view, showing the table as it falls, and its interaction with the indexer.  
         [0023]    [0023]FIG. 10 is an isometric view, showing the table as it falls, and its interaction with the indexer.  
         [0024]    [0024]FIG. 11 is an isometric view, showing the relief cuts needed in the indexer bracket.  
         [0025]    [0025]FIG. 12 is an isometric view, showing beakers in place on the table and a sample holding stand, with the table in its lowered position.  
         [0026]    [0026]FIG. 13 is an isometric view, showing beakers in place on the table and a sample holding stand, with the table in its raised position.  
         [0027]    [0027]FIG. 14 is a detail view of the items shown in FIG. 12.  
                                                 REFERENCE NUMERALS IN THE DRAWINGS                                10   base   12   air cylinder       14   cylinder rod   16   port       18   table   20   peg       22   indexer stand   24   indexer bracket       26   indexer   28   sample stand       30   motor   32   sample       34   beaker   36   optional angled portion       38   slot   40   mounting point       42   start point   44   end point       46   second vertical portion   48   anti-reversing junction       50   first vertical portion   52   first angled portion       54   second angled portion   56   relief cut                  
 
     
    
     DESCRIPTION OF THE INVENTION  
       [0028]    [0028]FIG. 1 depicts the most basic elements of the invention. Base  10  is a substantially rigid plate for mounting the other elements. Air cylinder  12  is attached to base  10 . Cylinder rod  14  extends and retracts from air cylinder  12  as air pressure is applied through port  16 . Air pressure is conventionally applied through a flexible hose, which is not shown. Table 18 is affixed to the top of cylinder rod  14 . FIG. 1 shows cylinder rod  14  in its retracted position, which corresponds to table  18  being in its lowered position.  
         [0029]    In FIG. 2, air pressure has been applied and cylinder rod  14  has extended upward—as indicated by the arrow. Table  18  is correspondingly raised to its upper position. Thus, the reader will appreciate that a conventional air cyslinder is used to produce purely vertical motion of an attached table.  
         [0030]    [0030]FIG. 3 shows several additional elements. Indexer  26  is mounted near the circumfrence of table  18 . Indexer  26  is attached to indexer bracket  24 , which is held in place by indexer stand  22 . Indexer stand  22  is attached to base 10.  
         [0031]    The reader will observe that table  18  has a number of evenly spaced pegs  20  radiating outward from its circular perimeter. Indexer  26  has slot  38  cut into its side facing table  18 . Slot  38  is sized to receive and guide a peg  20  as table  18  is moved between its lower and upper positions.  
         [0032]    [0032]FIG. 4 shows indexer  26  in more detail. The reader will observe that it has a curved shape, designed to fit closely against the circular perimeter of table  18 . FIG. 4 is looking at the near side of indexer  26 , which is the side facing table  18 .  
         [0033]    Slot  38  is comprised of several distinct portions. Start point  42  is the point where a particular peg  20  will first enter slot  38  (more detailed views describing the interaction of the slot and the pegs follow). Optional angled portion  36  is the first segment encountered. This segment is referred to as “optional” because it is not essential to the operation of the device. The remaining segments are first vertical portion  50 , first angled portion  48 , second vertical portion  46 , and second angled portion  54 . End point  44  is the point where a particular peg  20  will leave slot  38 .  
         [0034]    Four mounting points  40  are provided to mount indexer  26  to indexer mounting bracket  24 . Relief cuts  56  are provided to allow a particular peg  20  to engage and disengage from indexer  26 .  
         [0035]    [0035]FIGS. 5 through 10 depict the interaction of a particular peg  20  with indexer  26 , with continuous reference also being made to the details disclosed in FIG. 4. FIG. 5 shows table  18  in its lower position, which represents the start of an indexing cycle. The far side of indexer  26  is shown (opposite side from the one depicted in FIG. 4) The right-hand of the two labeled pegs  20  is poised to enter slot  38 . Likewise, the lefthand peg  20  is poised to disengage from slot  38 .  
         [0036]    [0036]FIG. 6 shows table  18  as it has started to move upward. The reader will observe that the right-hand peg  20  has encountered optional angled portion  36  and has moved into first vertical portion  50 . The result is that table  18  has rotated slightly clockwise (as viewed from above) as it rose, and then transitioned to purely vertical motion—as indicated by the arrow. The reader will observe that the lefthand peg  20  is completely disengaged.  
         [0037]    [0037]FIG. 7 shows table  18  as it has moved further upward. The right-hand peg  20  has moved through first angled portion  52 . During that portion, table  18  rotated clockwise as it rose. As shown, the right-hand peg  20  has entered second vertical portion  46 . Table  18  will only move vertically during this phase because the right-hand peg  20  remains within second vertical portion  46 .  
         [0038]    [0038]FIG. 8 shows table  18  at the upper limit of its travel. Its motion is purely vertical. After the point shown in FIG. 8, the air pressure will be released from air cylinder  12  and gravity will pull table  18  downward. It is important for the reader to appreciate that the motion of table  18  is purely an up and down stroke near the top of its cycle. This motion is desirable for many operations—as will be explained subsequently.  
         [0039]    As table  18  descends from the position shown in FIG. 8, the right-hand peg  20  will encounter anti-reversing junction  48 . The design of this junction is obviously significant. First angled portion  52  intersects second vertical portion  46  a significant distance upward from the lower extreme of second vertical portion  46  (the upper extreme of first angled portion  52  is higher than the lower extreme of second vertical portion  46 ). The junction is designed to ensure that the right-hand peg  20  descends to the bottom of second vertical portion  46 , rather than going back into first angled portion  52 .  
         [0040]    [0040]FIG. 9 shows the motion as table  18  descends. The right-hand peg  20  has descended past anti-reversing joint  48  and entered second angled portion  54 . The motion of table  18  at this point is downward translation accompanied by clockwise rotation. FIG. 10 shows further progress of this motion. The reader will observe that the right-hand peg  20  is approaching the position that the lefthand peg  20  occupied in FIG. 5. The reader will also observe that a new peg  20  is about to enter start point  42 . Thus, the cycle is completed. Those skilled in the art will realize that by configuring slot  38  to conform to the spacing between pegs  20 , the invention will continuously index via the simple raising and lowering motion of air cylinder  12 .  
         [0041]    It is important to realize why optional angled portion  36  is referred to as “optional.” It is possible to design a functional version of the device which omits this element. Those skilled in the art will realize that as table  18  descends from FIG. 9 to FIG. 10, table  18  is rotating clockwise. If table  18  has any significant mass, this rotation will produce angular momentum. Such angular momentum will cause the peg  20  which is exiting slot  38  to rotate clear and the next peg  20  to rotate into position until it come to rest at the bottom of first vertical portion  50 . Thus, the indexing function of optional angled portion  36  is not needed.  
         [0042]    However, those skilled in the art will also realize that friction in the system may inhibit rotation as the device ages. Without optional angled portion  36 , one cannot guarantee that the device will not reverse itself and become stuck in one indexing cycle. Accordingly, the version using optional angled portion  36  is the preferred embodiment.  
         [0043]    [0043]FIG. 11 is a detailed view showing a relief cut  56  made in indexer bracket  24 . A similar cut is found in the far side of indexer bracket  24 . Such relief cuts are obviously necessary to allow the free passage of pegs  20 .  
         [0044]    Having described the indexing and rotation mechanism in great detail, one might naturally wish to know about some applications for the mechanism. Accordingly, one particularly suitable application will now be disclosed. However, it is important for the reader to realize that the device has many applications in many different fields. Its consideration should not be limited to the following application.  
         [0045]    [0045]FIG. 12 depicts table  18  holding eight beakers  34 . Table  18  may optionally have a polar array of recesses sized to hold beakers  34 , or any other desired object. Beakers  34  typically contain liquids. Sample stand  28  is attached to base  10 . It suspends sample  32  directly over one of the beakers  34 . Motor  30  is provided to spin sample  32 , which is helpful in some situations. FIG. 12 shows table  18  as a peg  20  has entered second vertical portion  46  of slot  38 . As explained previously, the motion of table  38  at this point is a purely up and down vertical stroke.  
         [0046]    In FIG. 13, table  18  has moved to the upper limit of its motion. As a result, sample  32  has been immersed within the contents of the particular beaker  34 . As the air pressure is removed from air cylinder  12 , the particular beaker  34  will drop and sample  32  will pull free again. FIG. 14 shows a detail view of sample  32  as it has pulled free of a particular beaker  34 .  
         [0047]    The indexing motion of the device means that each successive beaker  34  will be brought directly beneath sample  32 , then moved up and down to immerse sample  32  within the contents of the beaker.  
         [0048]    As one particular example—sample  32  might be a silicon wafer. The object would be to deposit very thin layers of alternating polymers. Each successive beaker  34  would contain a polymer solution having an opposite charge (being an ionic solution) from its predecessor. As sample  32  is immersed in each successive beaker  34 , the alternating layers of polymers will adhere to sample  32  and accumulate.  
         [0049]    As another alternative, some of the beakers can contain distilled water or other cleaning solutions to purify sample  32  between successive active solutions. Virtually any type of chemical or process could be employed.  
         [0050]    Control of the device is quite simple, as the only input needed is the air pressure to air cylinder  12 . This air pressure can be controlled by a simple timer or a computer. Using a computer allows the cycle times to be varied. Thus, sample  32  could be immersed in some beakers for long periods and others for short periods.  
         [0051]    Accordingly, the reader will appreciate that the proposed invention can readily create linear and rotary motion using only a reciprocating linear input. The invention has further advantages in that:  
         [0052]    1. Virtually any combination of linear and rotary motion can be achieved by varying the design of slot  38 ;  
         [0053]    2. It allows purely linear motion over some parts of the travel;  
         [0054]    3. It requires only a single control input; and  
         [0055]    4. It is quite simple.  
         [0056]    Although the preceding description contains significant detail, it should not be construed as limiting the scope of the invention but rather as providing illustrations of the preferred embodiment of the invention. The device could be applied to many applications beyond chemical compositions, including spot welding, galvanizing processes, adhesive application, etc. Thus, the scope of the invention should be fixed by the following claims, rather than by the examples given.