Process of making hollow products, especially toys or pet products, and hollow products made with the process

Abstract

In the process of making a hollow product, especially a deformable toy ball, two halves made from on elastomeric material, a thermoplastic material, rubber, a blend of rubbers, or a thermoplastic elastomer are formed by injection molding with mating edges that engage with each other when the halves are assembled to form the product. The edge of one of the two halves is advantageously formed with a recess centered in the edge, in which a flange formed on the edge of the other of the two halves engages to provide a form-fitting connection between the two halves. The opposing edges are then bonded with each other by fusion or melting or by an adhesive applied to at least one of the edges prior to assembling the halves together. A deformable ball produced by the process is also described.

Claims

1. A process of making a hollow product, particularly a ball toy for children or pets, which comprises the steps of: molding a first hemispherical ball portion having a substantially spherical outer surface and a substantially spherical inner surface; forming the first hemispherical ball portion with a substantially flat arcuate mating surface, and forming an arcuate protrusion protruding from a portion of the substantially flat arcuate mating surface thereby forming an outward facing step; molding a second hemispherical ball portion with a substantially spherical outer surface and a substantially spherical inner surface; forming the second hemispherical ball portion with a substantially flat arcuate mating surface and forming an arcuate recess in a portion of the substantially flat arcuate mating surface of the second hemispherical ball portion for forming an inward facing step; and forming at least a first flange protruding from a portion of the substantially spherical inner surface of the second hemispherical ball portion, being substantially perpendicular to the substantially flat arcuate mating surface of the second hemispherical ball portion, and extending at least to the substantially flat arcuate mating surface of the second hemispherical ball portion, and being offset from the inward facing step; positioning the substantially flat arcuate mating surface of the first hemispherical ball portion adjacent to the substantially flat arcuate mating surface of the second hemispherical ball portion, and pressing the first hemispherical ball portion towards the second hemispherical ball portion causing engaging of the outward facing step of the first hemispherical ball portion with the inward facing step of the second hemispherical ball portion in a form fitting relation therewith, and in form fitting relation between the at least a first flange protruding from the portion of the substantially spherical inner surface of the second hemispherical ball portion and the outward facing step of the first hemispherical ball portion to form the hollow product; and placing the hollow product in a chamber, cryogenic cooling of the hollow product; and placing a polycarbonate media in the chamber; and tumbling of the chamber causing impacting of the polycarbonate media with frozen machine burrs for removing of the frozen burrs.

2. The process as defined in claim 1, wherein said forming at least a first flange comprises forming a first pair of planar flanges and forming a second pair of planar flanges each protruding from a portion of the substantially spherical inner surface of the second hemispherical ball portion, being substantially perpendicular to the substantially flat arcuate mating surface of the second hemispherical ball portion, and being spaced apart from each other.

3. The process as defined in claim 2, further comprising applying an adhesive to the substantially flat arcuate mating surface and the outward facing step of the first hemispherical ball portion before said pressing of the first hemispherical ball portion towards the second hemispherical ball portion.

4. The process as defined in claim 2, further comprising fusing or melting the substantially flat arcuate mating surface and outward facing step of the first hemispherical ball portion with the substantially flat arcuate mating surface and inward facing step of the second hemispherical ball portion.

5. The process as defined in claim 3, forming a spherical sector protruding from a portion of the substantially flat arcuate mating surface of the second hemispherical ball portion, and forming a corresponding annular recess and lip for receiving the protruding spherical sector therein, for improving mating of the first hemispherical ball portion and the second hemispherical ball portion.

6. The process as defined in claim 1, further comprising forming a plurality of openings in each of the first hemispherical ball portion and the second hemispherical ball portion.

7. The process as defined in claim 6, further comprising arranging the openings in eight groups uniformly spaced around the circumference of the ball and each of said eight groups comprises at least two of said openings arranged in a longitudinal direction from one side of the ball to the other.

8. The process as defined in claim 1, wherein the hollow product is made by injection molding.

9. A process of making a hollow product, particularly a toy for children or pets, which comprises the steps of: molding a first toy portion having an outer surface and a substantially smooth inner surface; forming the first toy portion with a substantially flat continuous mating surface, and forming a protrusion protruding from a portion of the substantially flat continuous mating surface thereby forming an outward facing step; molding a second toy portion with an outer surface and a substantially smooth inner surface; forming the second toy portion with a substantially flat continuous mating surface and forming a recess in a portion of the substantially flat continuous mating surface of the second toy portion for forming an inward facing step; and forming at least a first flange protruding from a portion of the substantially smooth inner surface of the second toy portion, being substantially perpendicular to the substantially flat continuous mating surface of the second toy portion, extending at least to the substantially flat continuous mating surface of the second toy portion, and being offset from the inward facing step; forming the at least a first flange in proximity to the inward facing step of the second hemispherical ball portion; positioning the substantially flat continuous mating surface of the first toy portion adjacent to the substantially flat continuous mating surface of the second toy portion, and pressing the first toy portion towards the second toy portion causing engaging of the outward facing step of the first toy portion with the inward facing step of the second toy portion in a form fitting relation therewith, and in form fitting relation between the at least a first flange protruding from the portion of the substantially smooth inner surface of the second toy portion and the outward facing step of the first toy portion; and placing the hollow product in a chamber; cryogenic cooling of the hollow product; and placing polycarbonate media in the chamber; and tumbling of the chamber causing impacting of the polycarbonate media with frozen machine burrs and removing of the frozen burrs.

10. The process of making a hollow product according to claim 9, wherein said forming at least a first flange comprises forming a first pair of planar flanges and forming a second pair of planar flanges each protruding from a portion of the substantially spherical inner surface of the second toy portion, being substantially perpendicular to the substantially flat arcuate mating surface of the second toy portion, and being spaced apart from each other.

11. The process of making a hollow product according to claim 10, further comprising forming the first pair of planar flanges and the second pair of planar flanges with each having a substantially triangular shape.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The objects, features and advantages of the invention will now be illustrated in more detail with the aid of the following description of a preferred process of manufacturing a hollow molded product of the invention, which is a deformable toy ball, with reference to the accompanying figures in which.

(2) FIG. 1 is a plan view of two halves of the ball in a mold part after formation of the two halves by a molding technique;

(3) FIG. 2 is a perspective view of one of the two halves of FIG. 1 shown in a guide plate with a metal or ceramic core positioned in it;

(4) FIG. 3 is a perspective view of the other half in another guide plate before it is positioned over the half shown in FIG. 2, so that it can be joined to the first half by adhesive means or by fusion;

(5) FIG. 4 is a plan view of one embodiment of a deformable ball made by the process according to the invention, which is provided with openings and polar holes in the body of the ball;

(6) FIG. 5 is a side view of the embodiment of the ball shown in FIG. 4;

(7) FIG. 6 is a cross-sectional view showing the interior of one of the two halves of the ball prior to assembly, and showing the recess for a form-fitting connection with the other half of the ball;

(8) FIG. 7 is a cross-sectional view showing the interior of the other of the two halves of the ball prior to assembly, and showing the flange that engages in the recess of the half shown in FIG. 6;

(9) FIG. 8 is shows a ball half having the recess broken into three parts;

(10) FIG. 9A is a perspective view of a first ball half for yet another embodiment of a molded ball assembly of the present invention;

(11) FIG. 9B is a front view of the ball half of FIG. 9A;

(12) FIG. 9C is a top view of the ball half of FIG. 9A;

(13) FIG. 9D is a bottom view of the ball half of FIG. 9A;

(14) FIG. 9E is a side view of the ball half of FIG. 9A;

(15) FIG. 10A is a perspective view of a second ball half for yet another embodiment of a molded ball assembly of the present invention;

(16) FIG. 10B is a front view of the ball half of FIG. 10A;

(17) FIG. 10C is a top view of the ball half of FIG. 10A;

(18) FIG. 10D is a bottom view of the ball half of FIG. 10A;

(19) FIG. 10E is a side view of the ball half of FIG. 10A;

(20) FIG. 11 is a section cut through the first ball half shown in the side view of FIG. 9E, and further illustrates a keyway at a polar location;

(21) FIG. 12 is a section cut through the second ball half shown in the side view of FIG. 10B, and further illustrates a key at a polar location;

(22) FIG. 13 is a section cut showing the first ball half of FIG. 1 and the second ball half of FIG. 12 after being mated; and

(23) FIG. 14 shows a first and second ball half of yet another embodiment, which is formed similar to the ball halves of FIGS. 9A-9E and FIGS. 10A-10E, but each has poles holes rather than an interlocking key and keyway.

DETAILED DESCRIPTION OF THE INVENTION

(24) As used throughout this specification, the word may is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). Similarly, the words include, including, and includes mean including but not limited to.

(25) The phrases at least one, one or more, and and/or are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions at least one of A. B and C, one or more of A, B, and C, and A, B, and/or C means all of the following possible combinations: A alone; or B alone; or C alone; or A and B together; or A and C together; or B and C together; or A, B and C together.

(26) Furthermore, the described features, advantages, and characteristics of any particular embodiment disclosed in the following specification, may be combined in any suitable manner with any of the other embodiments disclosed herein.

(27) In a first step of one embodiment of the process for making a hollow ball 10 or other hollow product according to the invention, two members in this case, halves 12, 14 of the ball CB are formed or molded by e.g., an injection molding technique. FIG. 1 shows the two halves 12, 14 of the ball CB, which are approximately hemispherical in shape, in a mold part 21 after being formed by injection molding. Each half 12, 14 has an outer peripheral edge 16, 16 (see FIGS. 6 and 7). The edge 16 of one 12 of the two halves is provided with one or more recesses 112 that is preferably centered in the edge (as shown in FIGS. 2 and 6), which engages with a mating flange or protrusion 212 that extends from the edge 16 of the other half 14 (as shown in FIGS. 3 and 7) when the halves 12, 14 are assembled to form the ball CB. The recess 112 extends circumferentially around the generally hemispherical half 12, but may be broken into segments 112a, 112b (FIG. 2) that only extend part way (about half way) around the circumference of the half 12, in which corresponding sections 212a, 212b of the flange or protrusion 212 engage in a form-fitting connection. In another example, shown in FIG. 8, there may be a three-part recess that may include recess 112C, recess 112D, and recess 112E.

(28) FIG. 2 shows a metal core 32 positioned in one 12 of the two halves 12, 14 with its edge 16 provided with recess 112 exposed on one side of a guide plate 23. The approximately hemispheric half 12 is held in a cavity provided centrally in the guide plate 23.

(29) FIG. 3 shows the other half 14 of the two halves 12, 14 arranged in another guide plate 25. The other half 14 has a flange 212, which engages in the recess 112, when the one half 12 of the two halves is placed over the other half 14.

(30) In a subsequent step of this embodiment of the process the one half 12 is placed over the other half 14 with their edges 16, 16 in an opposing relationship and then the edges 16, 16 of the two halves 12, 14 are pressed, pushed, or forced together, so that the flange or protrusion 212 engages in the recess 112 in a form-fitting connection, i.e., so that the edges 16, 16 of the two halves 12, 14 mate with each other or are in a mating relationship with each other. In the embodiment shown in the drawing this may be accomplished by assembling the other guide plate 25 holding the half 14 together with the guide plate 23 holding the half 12 by sliding the guide rods 312 into the guiding holes 314 shown in FIGS. 2 and 3.

(31) In this embodiment of the process after the mating edges 16, 16 of the two halves 12, 14 are put in a form-fitting connection with each other they are fused or melted by heating so that the edges 16, 16 of the two halves 12, 14 are securely bonded to each other to form the hollow product, which is the deformable ball CB.

(32) In alternative embodiments of the process an adhesive may be applied to the edges 16, 16 of at least one of the edges 16 or 16 prior to putting the halves together, so that the mating edges 16, 16 are bonded together when the halves 12, 14 are assembled with their edges engaged with each other to form the hollow product, namely the ball CB. In one embodiment the adhesive may be a Cyanoacrylate based adhesive preferably Ethyl-2-cyanoacrylate and blends thereof with Poly(methyl methacrylate) (PMMA). The Ethyl-2-cyanoacrylate blends with Poly(methyl methacrylate) (PMMA) are preferably about 85% to 98% by weight Ethyl-2-cyanoacrylate with about 2 to 15% by weight Poly(methyl methacrylate) (PMMA). More preferably the adhesive is 90-95% by weight Ethyl-2-cyanoacrylate and 5-10% by weight Poly(methyl methacrylate) (PMMA). In another embodiment, the adhesive may be composed of a blend of 60% or more natural rubber and Neoprene. A preferred composition of the adhesive may be 70% or more natural rubber and Neoprene and the rest of the composition may be gasoline fillers. In another embodiment of the adhesive, it may simply be a product named Cyanoacrylate Adhesive Lem Super, which is available from Zhejiang Golden Roc Chemical Co., LTD, and which is an ethyl-2-cyanoacrylate having the molecular formula C.sub.6H.sub.7NO.sub.2.

(33) The metal core 32 must be removed after bonding the respective halves 12, 14 together at their mating edges 16, 16 to form the ball CB by pulling the core 32 out of the finished deformable product through an opening in the product after the members have been fused together.

(34) The halves 12, 14 may be molded from an elastomeric material, a thermoplastic material, rubber, a blend of rubbers, or a thermoplastic elastomeric material in a molding machine or apparatus. Such machines or apparatus are known and are marketed via the Internet. In some embodiments of the process the hemispheric halves or parts 12, 14 would be made by molding, e.g. injection molding. The cavity of the mold would be shaped or conformed to provide the desired shape and dimensions of the halves 12, 14 by methods that are well known to those skilled in the art of molding thermoplastic or elastomeric materials to form articles of various shapes. The mold would also be configured to provide the openings 19 and polar holes 119 in the ball.

(35) One embodiment of the ball CB, which is made by the process and shown in FIGS. 4-7, has a body W provided with twenty-four openings 19. The openings 19 in the embodiment shown in FIGS. 4 to 7 are arranged in eight groups G with three openings 19 in each group. The eight groups G are arranged equally spaced around the circumference of the ball CB in the embodiment shown in FIGS. 4 and 5. The three openings 19 in each group G are arranged in a row extending longitudinally between the opposite sides or ends of the ball CB. In addition, polar holes 119 are provided at opposite sides or ends of the ball CB in the embodiment shown in FIGS. 4 to 7, which may also include a spherical sector 119S that may mate with a corresponding recess 119R and lip 119L for improved mating/retention.

(36) The two halves 12, 14 are shown prior to bonding the mating edges 16 with each other in FIGS. 6 and 7. The half 12 with the recess 112 in the edge 16 is shown in FIG. 6 and the half 14 with the flange 212 in the edge 16 is shown in FIG. 7.

(37) Various embodiments of the ball may have a hollow interior space of any of a variety of sizes so that the body of the ball may have any of a variety of different thicknesses. In addition, the shape of the ball need not be perfectly spherical, but might have a shape similar to a football or other type of ball in other embodiments of the invention. Furthermore the hemispherical parts or halves may have openings 19, as shown in FIGS. 1, 3, and 4 to 7, which make the product made by the process, in this case of a ball, easier to squeeze, deform or compress. In addition the product may have polar holes of various sizes in different embodiments.

(38) In alternative embodiments the two halves may engage with each other by structural means that differ from the flange or protrusion on the edge of one of the two halves and the recess provided in the edge of the other of the two halves prior to being securely attached with an adhesive or by fusion. For example, a bayonet coupling or snap-in connection is conceivable.

(39) An alternative embodiment is shown by a ball 400 in FIG. 13, being formed using the two ball halves illustrated in FIG. 11 and FIG. 12. The first ball half 410 is shown in detail in FIGS. 9A-9E, and the second half ball 420 is shown in detail in FIGS. 10A-10E. Each of the ball halves 410, 420 may include at least one opening 409, and together they may have a total of twenty-four openings (twelve openings for each half), as described above for ball 10.

(40) However, ball halves 410 and 420 may utilize a different arrangement for mating of the halves. Ball half 420 may have an arcuate recess, but rather than being formed entirely on the flat mating surface at the illustrated split line 400X (which is actually a plane in three-dimensional spaced, but is referred to hereinafter simply as the split line) to be substantially centered thereat, a recess 421 may instead be formed upon the inner half of the mating surface to create an inward facing step 421S. For ball half 410, rather than forming a protrusion that may be centered upon the mating surface, a protrusion 411 may instead be formed upon the inner half of the mating surface (as observed in the cross-sectional view), which protrusion may extend beyond the split line 400X to create an outward facing step 411. The outward facing step 411S of the ball half 410 may be engaged within the inward facing step 421S of ball half 420, as seen in FIG. 13. To further improve upon the joining of the two halves, the ball half 410 may be formed with a rectangularly-shaped keyway opening 410W, which may be engaged by a corresponding rectangular-shaped key (i.e., a protrusion) 420K formed on ball half 420, as seen in FIGS. 11 and 12. The strength of the joining may be aided by the use of a pair of flanges 422A/422B on the ball half 420 and offset from the inward facing step, as seen in FIG. 12, the ends of which may serve to locally trap the protrusion 411 of ball half 420, between those ends and the inward facing step 421 of ball half 420 (FIG. 13). Two pairs of flanges (e.g., 422A/422B, and 423A/423B) may be used on the ball half 420, as seen in FIG. 10C. The flanges 422A/422B may be planar, and may be oriented to be substantially perpendicular to the plane formed at the split line 400X. The end of the flanges may terminate in a cylindrical pin, as seen for ball half 520 in FIG. 11, which pin ends may be used for the trapping of the protrusion 411 of ball half 520, which may mate with ball half 510, also shown therein.

(41) As part of the method of forming the ball, since it is made of rubber, it has to trimmed. Traditionally the trimming had been done by hand, but labor costs have become too expensive. More cost-effective results can now be obtained using a tumbler machine that is available from, for example, the Guangzhou RuiMei Rubber & Plastic Machinery Development Co. It uses a low temperature environment and adds pellets that clean the rubber edges as the tumbler agitates the pellets. To prevent the process from adversely affecting the toys, the product (e.g., the ball halves) may be cured for 24 to 72 hours (preferably 48 hours) before they are processed by the machine. (Notethis curing time is not needed for when the ball halves are trimmed by hand). The process involves Nitrofreeze deburring of the parts for the removal of burrs created during machining and/or other operations performed on plastic, rubber and even metal parts. The deburring does not affect the surface finish or geometry of the part. The deburring tool provides a safe, clean and cost effective alternative to traditional hand, vibratory or tumbling methods. The ports to be deburred are placed in a chamber, cooled and impacted with polycarbonate media. The machine burrs are frozen and removed quickly and cleanly by the passing non-abrasive polycarbonate media. Little to no dust or residue remains. Only the offensive burrs are removed. The edges are maintained without rounding or other material removal occurring.

(42) While the invention has been illustrated and described as embodied in a process of making hollow products, especially toys or pet products, e.g., a deformable ball, it is not intended to be limited to the details shown, since understandably various modifications and changes may be made without departing in any way from the spirit of the present invention.