Patent Application
20090031904
This invention generally relates to a magnetic rotating device used in the indexing of a golf ball for the purpose of printing indicia on multiple surfaces. This invention more particularly relates to a device that magnetically controls the orientation of the golf ball in predetermined positions.
More than seven hundred million golf balls are produced each year, a significant percentage of which have indicia or logos printed on their outer surface. The indicia typically include any one of the golf ball company, trade name, a number, or an image, such as a corporate or country club logo. The indicia are typically printed on a base-coated surface of the cover of the golf ball, and covered with a top-coating to prevent damage during impact with a golf club. Thus, the indicia must have a perfect appearance since it is often the most distinctive quality of a golf ball.
The golf bail cover typically contains a white or other colored concentrate, or is painted. The most common method for adding a logo to the dimpled surface of a golf ball is by pad printing, although other methods, such as inkjet printing, are adaptable for such surfaces. However, whatever method is used the golf ball must be first, oriented for the printing step(s), secondly, they must be printed on at least three sides, preferably four, and finally, there must be a method of inspection for those golf balls, which during the process have a flaw or defect in the printing.
There has been a continuing desire to achieve high production rates. Because automated apparatus typically may function faster than human operators, there has been an ongoing goal to reduce, if not eliminate, human intervention during the manufacturing process. Thus, each of the above processes is typically done at a separate automated processing station functioning at optimal efficiency and speed so that the overall production rate is maintained at the desired high level. For instance, pad-printing apparatus preferably includes an array of print-pads arranged to apply a production print sequentially on various locations on the surface of the golf ball, the golf ball being indexed before being passed to the next print-pad.
The pad printing process begins by spreading ink across the surface of a pad printing cliche or “plate” containing etched or depressed version of the desired image. Ink is dispersed over the etched area and excess ink is removed with a “doctor” blade or cup. Upon exposure to air, thinner evaporates from the ink causing it's surface to become “tacky.” A smooth, resilient, block of silicone rubber (the “pad”) is brought into contact with the tacky surface of the ink. As the pad is withdrawn from the plate surface, an adhering film of ink is transferred to the pad. The ink is carried on the pad to the target area on the golf ball surface, during which time thinner in the ink further evaporates, causing the exposed ink surface on the pad to become tacky. Upon contact with the golf ball surface, the film of ink is transferred from the pad to the ball surface.
Pad printing plates are typically stiff plates coated with a photopolymer material that cures upon exposure to UV light. The etched version of the image is formed by placing a film positive of the image over the plate and irradiating the surface with UV light. In this manner, the exposed areas of the plate harden, while blocked areas remain soft. The soft polymer is then removed by a series of washing steps, creating etched areas correlating to the logo.
While the golf industry needs improvement in automatically orienting, printing and inspecting golf balls produced by high speed production lines, the challenge is in the indexing of the golf ball such that multiple surfaces of the ball are presented sequentially and with extreme precision to the pad printers for the printing of indicia without interrupting the production cycle. This requires accurate indexing of the ball and the maintaining of that index.
The present invention is directed to a magnetic indexing device that firmly holds a golf ball in a particular orientation while the ball moves along a conveyor for the purpose of having indicia applied by multiple pad print heads. The device has means to cooperate with transfer mechanisms, and station locks to provide exposures of various ball surfaces for printing by articulating pad printers.
The device is comprised of a stationary base portion which is affixed to a conveyor, and a rotating cup portion which is magnetically connected to the base portion. Each portion has recesses for housing magnets that therein create a magnetic field of attraction which firmly locks the two portions together. When rotation of the cup portion to the base portion is required, the rotation is substantially friction-free because of a thrust bearing ring set in the base portion. The cup portion is caused to rotate 45° or 90° upon being biasly urged by station locks located on the conveyor. The cup portion has an open bridge section wherein cam surfaces of the station locks can engage and cause the cup portion to rotate for each new procedure, whether it be inspection of the ball, pad printing of indicia and logo, or curing the printed ink with ultraviolet light.
The device includes a hemispherical cavity having an inner surface that defines a reverse golf ball dimple pattern. A transfer mechanism takes a newly oriented ball and deposits in the hemispherical cavity and aided by slide devices, that are attached to the conveyor, flexible fingers located on opposing sides of the cavity are pushed into an open position for the reception of an oriented golf ball.
Golf balls that have indicia printed on them using the device of the present invention are placed into the apparatus in a bulk quantity. Each ball is oriented by an imaging station that uses software to load a complete pattern trajectory to a computer with a single communications transaction via Ethernet. Upon the ball being properly oriented, a transfer mechanism picks the oriented ball up and deposits it into a hemispherical cavity of a device attached to a sled on the conveyor, all while maintaining a precise predetermined relationship between the ball and the cavity, wherein the ball is firmly held in the cavity by the pair of fingers. To allow access of the ball into the hemispherical cavity, parallel sliders operate in tandem to push open the fingers to allow the depositing of the ball. The golf ball remains oriented in the cavity for the entire printing process, and since it is the cup portion of the device that is rotated, various surfaces of the ball are exposed for printing. The pad printing of indicia may include player number, brand, source of origin, logo, etc.
An object of the present invention is to reduce or eliminate wear and tear on a high speed conveyor line where all movement is automatically generated. The device provides for virtual frictionless rotation to reduce any mechanical wear by having the rotation glide over a ball bearing ring. Multiple station locks, which are located along the conveyor, engage the device and cause the cup portion to rotate (index) therein exposing a new surface for either printing, inspection, or curing. To maintain the cup in position between station locks is the function of the magnets that are disposed in the device. Magnets in the stationary base portion of the device develop a magnetic field with the magnets located in the rotating cup portion. As the devices move along the conveyor, the station locks use an engaging cam section to mesh with an open bridge section of the device to rotate it from a previous position to a new position. At the new position, printing, inspection, or curing procedures are performed, all while the station lock holds the cup device in position. Upon completion of the procedure, the station locks release the device to move along the conveyor line for the next procedure. It is the magnetic forces of the device that hold the rotating cup portion securely to the base portion. Since the device is without any mechanical locking parts, it is the magnetic force of the magnets that firmly holds the rotating portion to the base portion.
The ball held by the device is subjected to printing by multiple articulated pad print heads that employ UV curable inks supplied to each print head by a fully integrated ink viscosity control system, and the inspection of all printed sites of the ball is performed by a vision print quality inspection system which removes from the conveyor line any ball failing the inspection. A UV curing system is utilized to dry the ink. Whether it be to expose a ball surface for printing, or to expose a surface for inspection, or to expose a surface for curing, or to place the ball in position for removal from the conveyor, each step requires the device to be indexed by a station lock and subsequently held in place by the magnets between station lock positions.
In the accompanying drawings, which form a part of the specification and are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views, the drawings are:
As illustrated in the accompanying drawings and discussed in detail below, one embodiment of the present invention is directed to a magnetic indexing device 20 that firmly holds a golf ball. Multiple indexing devices 20 are secured to a sled 28 on an endless conveyor 14, as shown on
As best shown in
The stationary base portion 44 includes a square platform 45 that is mechanically connected to the conveyor sled 28 by well known means such as bolting the platform to a sled 28 that is integral with the conveyor 14; a plurality of recesses 47 are defined in the upper surface 49 of the platform 45, preferably eight (8), for seating a plurality of bottom magnets 51 with the north poles of the magnets facing upwards; a circular channel 48 is defined on the top surface 49 of the platform 45; a bottom metallic washer ring 53 is seated in the channel 48 and held in place by the magnetic force generated by the bottom magnets 51; a thrust bearing ring 55 is juxtaposed on top of the bottom washer ring 53 and it also is held by the magnetic force; and, an alignment pin 57 that is integral with the platform 45 and extends upwards to align the stationary base portion 44 to the rotating cup portion 46 when the two portions are brought together.
The rotating cup portion 46 comprises: a lower circular member 50, of a size and shape to be a positioned in the channel 48 of the base portion 44; the lower circular member 50 having a bottom surface 59 defining a plurality of recesses (not shown) for housing a corresponding number of top magnets 74, the south poles of which face downwards to create a magnetic locking force between the base and cup portions 44, 46; a plurality of threaded ports 52 are spaced about the outer perimeter of the lower circular member 50 for receiving tightening bolts which help secure the top magnets 74 in place; a circular aperture (not shown) is defined through the center of the rotating cup portion 46 for housing a bushing 72 which mates with the alignment pin 57 of the base portion 44 to facilitate joining the two portions 44 and 46; a circular upper member 63 supports the main body 65 of the rotating cup portion 46; the upper member 63 is connected to the lower circular member 50 by a plurality of shoulder bolts 56, preferably at least 8, which are threaded into the bottom surface of the upper member 63 and the unthreaded sections 61 provide spacing between the lower and upper circular members 50, 63 to create a bridge-like opening 54 (shown on
The apparatus 10, as shown on
The process requires a station lock for each index. Thus, if after a first surface is printed upon, the ball must be then rotated by a station lock to expose another surface for printing, and the ball must be rotated again when the inspection of a second surface is required, and the ball must further be rotated for the curing process. The function of the station locks 26 is to break the magnetic attraction and biasly rotate the cup portion 46 to a new position and securely hold the cup portion (therein the ball) for the particular process step which includes printing, inspecting, curing, and removal from the cup. The function of the magnets 51 and 74 is to hold fast the device 20 while it travels between station locks 26, otherwise the cup portion 46 would spin freely in relationship to the base portion 44.
The magnetic indexing device 20 is the key component of the printing system described above and on
The articulated pad printing system 16 utilizes ultraviolet (“UV”) curable inks. UV inks are typically cured by means of UV light having wavelengths of from about 180 nm to about 380 nm. The advantages of using UV ink are that they are not fast and cure thoroughly, they are easy to use and are not affected by small changes in ambient conditions, they retain constant viscosity (i.e., they do not dry up quickly), and they use smaller amounts of combustible organic solvent such that little or no solvent fumes escape into the working environment and are, therefore, environmentally safer. Small amounts of solvent may be added to the UV inks for certain applications to enable the ink to transfer in a conventional manner. The inks may optionally contain additives such as binders, reactive prepolymers, thinners, low-viscosity mono and poly-functional monomers, photoinitiators to stimulate polymerization, stabilizing additives, flow control agents, wetting agents, pigments, extenders, or combinations thereof. The thickness of the ink film transferred to the golf ball can be any thickness that is sufficient to provide a clear image of the indicia or logo. This thickness can be from about 4 to 50 μm, preferably from about 4 to 20 μm. The thickness of the ink film can vary with the ink type and color, and is also influenced by the ink's viscosity, the pad material, the depth of etching in the plate and also environmental factors such as temperature, humidity, and so on.
The term “about” as used herein in connection with one or more numbers or numerical ranges, should be understood to refer to all such numbers, including all numbers in a range.
The invention described and claimed herein is not to be limited in scope by the specific embodiments herein disclosed, since these embodiments are intended solely as illustrations of several aspects of the invention. Any equivalent embodiments are intended to be within the scope of this invention. Indeed, various modifications of the invention in addition to those shown and described herein will become apparent to those of ordinary skill in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims
