Abstract:
A manufacturing process of a patio tabletop glass with broken protection includes the steps of fully cleaning at least a top surface of a tempered glass layer which has a central hole thereon, drying the cleaned tempered glass layer, heating the entire tempered glass layer to a temperature between 45° C. to 65° C.; evenly applying a layer of acrylic adhesive on the top surface of the tempered glass layer which temperature is maintained between 45° C. to 65° C. to form the adhesive layer; attaching the protection layer on the tempered glass layer, cutting excessive edges of the protection layer to a size identical to the tempered glass layer; and forming a center hole on the protection layer, which coaxially aligns with the central hole of the tempered glass layer. Accordingly, even when the patio table top is broken into pieces and particles, the broken glass pieces and particles will not be breaking apart and remain attaching to a protection layer.

Description:
CROSS REFERENCE OF RELATED APPLICATION 
     This is a Continuation-In-Part Application of a non-provisional application, application Ser. No. 09/206,922, filed Dec. 07, 1998, now abandoned. 
    
    
     FIELD OF THE PRESENT INVENTION 
     The present invention relates-to an outdoor tabletop glass, and more particularly to a manufacturing process of patio tabletop glass with broken protection to prevent the broken glass particles from hurting the users when the patio tabletop glass is accidentally broken. 
     BACKGROUND OF THE PRESENT INVENTION 
     Patio table is one of the most popular outdoor furniture, which normally is placed on the patio or in the back yard for the users to rest and serve barbecue. For easy cleaning, decorating and other reasons, most patio table has a glass made tabletop. The tabletop glass, which is simply placed on top of a table frame, generally has a central hole adapted to hold an umbrella in position for sunshine shading. 
     The biggest shortcoming of the patio tabletop glass is its fragile nature especially when using outdoors. It is reported that even though most of the patio tabletop glasses are made of tempered glass, the patio tabletop. glass may be broken when its surface is impacted with a sharp object; when it falls on the ground; or when a small stone hits on it in high speed. The central hole of the patio tabletop glass is the most weakened area because of the high concentrate stress occurred around the hole. Besides, when wild wind blows on the opened umbrella, it may cause the whole patio table to fall down and break the tabletop glass. 
     No matter if the patio tabletop glass is broken by any aforesaid reason or other unexpected reasons, the glass is broken into particles and/or pieces with sharp edges that may cause serious body injury to the users, especially to the minors. However, no glass is unbreakable. Thus, the applicant of the present invention seeks a different way to resolve the above problem, i.e. to prevent the broken glass pieces and particles from breaking apart. 
     SUMMARY OF THE PRESENT INVENTION 
     It is thus a first object of the present invention to provide a patio tabletop glass with broken protection and the manufacturing process thereof, wherein even when the patio tabletop glass is broken into pieces and particles, the broken glass pieces and particles will not break apart and remain attached to a protection layer. 
     A further object of the present invention is to provide a manufacturing process of patio tabletop glass which is fast and inexpensive and adapted for mass production. 
     Another object of the present invention is to provide a manufacturing process of patio tabletop glass with broken protection, which provides a process of forming a central hole on a protection layer after it is firmly adhered on a tempered glass layer without causing an elongated bubble popping up between the tempered glass layer and the protective layer and extending from the edge of the central hole to the peripheral edge of the tabletop glass. 
     Another object of the present invention is to provide a patio tabletop glass with broken protection, wherein the round edge of the center hole of the protection layer is made to form a protective edge extended around the central hole of the tempered glass layer which is the most weakened area because of the high concentrate stress occurred around the central hole. 
     Accordingly, in order to accomplish the above objects, the present invention provides a patio tabletop glass with broken protection, which comprises a tempered glass layer having a predetermined shape and size, a protection layer made of polyvinyl chloride or polyester sheet having a thickness of 0.3 to 0.8 mm and a shape and size adapted to cover a top surface of the tempered glass layer, and an adhesive layer which has a preferred thickness between 0.1 to 0.2 mm and is made of acrylic adhesive and the like being evenly applied between the top surface of the tempered glass layer and a bottom surface of the protection layer so as to integrally adhere the protection layer with the tempered glass layer to form an one piece body, wherein the patio tabletop glass is manufactured by the steps of: 
     (a) fully cleaning at least the top surface of the tempered glass layer which has a central hole thereon with neutral water having a pH of 7 so as to remove any possible oil is thereon; 
     (b) drying the cleaned tempered glass layer; 
     (c) heating the entire tempered glass layer to a temperature between 45° C. to 65° C.; 
     (d). evenly applying a kind of acrylic adhesive on the top surface of the tempered glass layer which temperature is maintained between 45° C. to 65° C. to form the adhesive layer; 
     (e) attaching the protection layer having a thickness of 0.3 to 0.8 mm and a width size larger than the tempered glass layer on top of the adhesive layer of the tempered glass layer by pressing the protection layer against the top surface of the tempered glass layer which is maintained at the temperature of 45° C. to 65° C. until the protection layer is integrally attached on the tempered glass layer, wherein the protection layer has a circular center portion formed above the central hole of the tempered glass layer; 
     (f) cutting excessive edges of the protection layer to a size identical to the tempered glass layer; and 
     (g) forming a center hole on the protection layer, which coaxially aligns with the central hole of the tempered glass layer. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a sectional view of the patio tabletop glass in accordance with the above preferred embodiment of the present invention. 
     FIG. 2 is a flow diagram of a manufacturing process for producing a patio tabletop glass in accordance with a preferred embodiment of the present invention. 
     FIG. 3 is a perspective view illustrating the cutting step in accordance with the above preferred embodiment of the present invention. 
     FIG. 4 is a sectional view illustrating how the protection layer is ensured to perfectly stick on the tempered glass layer in accordance with the above preferred embodiment. 
     FIG. 5 is a flow diagram of a process of forming the center hole on the protection layer in accordance with the above preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1 and 2, a preferred embodiment of the present invention is illustrated. As shown in FIG. 2, a patio tabletop glass  10  of the present invention comprises a tempered glass layer  11 , a protection layer  12  and an adhesive layer  13 . The tempered glass layer  11  has a predetermined shape, thickness and width size and a central hole  111  provided thereon. The protection layer  12  is made of polyvinyl chloride or polyester sheet having a thickness of 0.3 to 0.8 mm and a shape and width size identical to that of the tempered glass layer  11 . 
     The tempered glass layer  11  is generally made of figured glass that has an uneven top surface  112  having specific decorative pattern. The protection layer  12  is integrally attached on the top surface  112  of the tempered glass layer  11  and has a center hole  121  formed thereon, wherein the center hole  121  of the protection layer  12  has an identical diameter of the central hole  111  and is coaxially aligned with the central hole  111  of the tempered glass layer  11 . The adhesive layer, which has a preferred thickness between 0.1 to 0.2 mm and is made of acrylic adhesive and the like, is evenly applied between the top surface  112  of the tempered glass layer  11  and a bottom surface  122  of the protection layer  12  so as to integrally adhere the protection layer  12  with the tempered glass layer  11  to form an one piece body. Moreover, the tension of a periphery portion  123  of the protection layer  12  is increased to form a protective edge  124 , i.e. the round edge of the center hole  121 , which is made to extend around the central hole of the tempered glass layer which is the most weakened area because of the high concentrate stress occurred around the central hole, and to ensure the periphery portion  123  of the protection layer  12  around the center hole  121  securely attached around the central hole  111  on the tempered glass layer  11 . 
     For mass production, as shown in FIGS. 1 to  5 , the structure of patio tabletop glass  10  as described above can be made according to the following steps: 
     (a) Provide a plurality of the tempered glass layers  11  each having the predetermined shape and width size as well as the central hole  111  provided thereon. 
     The step (a) further comprises the steps of cutting large piece of glass board to form a circular shaped glass layer having the specific decorative pattern provided on at least the top surface  112 , drilling the central hole  111  on the glass layer and tempering the glass layer by heating the glass layer to about 500° C. -550° C. and then immediately cooling down to 0° C. -40° C. to form the tempered glass layer  11 . 
     (b) Fully clean at least the top surface  112  of each of the tempered glass layers  11  with neutral water having a pH of 7 so as to remove any possible oil thereon. 
     (c) Dry all cleaned tempered glass layers  11 . 
     (d) Heat each of the tempered glass layers  11  entirely to a temperature between 45° C. to 65° C. 
     (e) Attach the protection layer  12  having a thickness of 0.3 to 0.8 mm and a width size larger than the tempered glass layer  11  on the top of the adhesive layer  13  of the tempered glass layer  11  by pressing the protection layer  12  against the top surface  112  of the tempered glass layer  11  which is maintained at the temperature of 45° C. to 65° C. until the protection layer  12  is integrally attached on the tempered glass layer  11 , wherein the protection layer  11  has a circular center portion  120  formed above the central hole  111  of the tempered glass layer  11 . 
     As shown in FIG. 2, the step (e) further comprises the following steps: 
     (e-1) Evenly apply a layer of acrylic adhesive or the like on the top surface  112  of each of the tempered glass layers  11  which temperature is maintained between 45° C. to 65° C. to form the adhesive layer  13  having the thickness of 0.1 to 0.2 mm. 
     (e-2) Provide a roll of continuous protection layer  12 ′ having the thickness of 0.3 to 0.8 mm and a width size larger than that of the tempered glass layers  11 . 
     The bottom surface of the continuous protection layer  12 ′ may also provided with a layer of acrylic adhesive or the like to facilitate the continuous protection layer  12 ′ to adhere to the tempered glass layers  11 . 
     (e-3) Feed one end of the protection layer  12 ′ and the plurality of tempered glass layers  11  one after one between a pair of parallel rubber rollers  21 ,  22 , wherein the continuous protection layer  12 ′ is attached on the top of the adhesive layers  13  of the tempered glass layers  11  in overlapped manner. The pair of parallel rubber rollers  21 ,  22  are arranged to press the continuous protection layer  12 ′ against the top surfaces  111  of the tempered glass layers  11 , which are still maintained at the temperature of 45° C. to 65° C., until the continuous protection layer  12 ′ is integrally adhered on the top surface  112  of each of the tempered glass layers  11 . 
     (e-4) As shown in. FIG. 3, cut off the continuous protection layer  12 ′ according to the number of the tempered glass layers  111  into a plurality of the protection layers  12 . 
     (f) As shown in FIG.  3 . cut away the excessive edges of each of the protection layers  12  to a size identical to the respective tempered glass layer  11 . 
     (g) As shown in FIGS. 2 and 3, form the center hole  121  on each of the protection layers  12  to coaxially align with the central hole  112  of the respective tempered glass layer  11  to form the patio tabletop glass  10 . 
     According to the present invention, the step (g) further comprises the steps of: 
     (g-1) pressing the center portion  120  of the protection layer  12  toward the central hole  111  of the tempered glass layer  11  that increases the tension of a peripheral portion  123  of the protection layer  12  attached around the central hole  111  of the tempered glass layer  11  to ensure the peripheral portion  123  of the protection layer  12  extending and attaching to an upper edge of the central hole  111  of the tempered glass layer  11 ; and 
     (g-2) grinding the upper edge of the central hole  111  of the tempered glass layer  11  until the center portion  120  of the protection layer  12  is separated from the protection layer  12  to form a center hole  121  coaxially aligned with the central hole  111  of the tempered glass layer  11 . 
     The step (g), as shown in FIG. 5, is a specific step designed to form the center hole  121  for the present invention. It should be noted that the center portion  120  is not directly cut from the protection layer  12  to form the center hole  121 . It is because if the center portion  120  is directly cut out from the protection layer  12 , the peripheral edge of the center hole  121  will not be fittedly attached to the upper edge of the central hole  111 , so that further grinding step may be required to remove the cutting edge of the center hole  121 . Moreover, to directly cut out the center portion  120  from the protection layer  12  will frequently cause an elongated bubble popping up between the tempered glass layer  11  and the protective layer  12  and extending from the edge of the central hole to the peripheral edge of the tabletop glass. 
     According to the present invention, no cutting is required to form the center hole  121 , wherein in the step (g-1), as shown in FIG. 5, a press mold  20 , which has a round shaped presser head  21  at one end thereof, is used to coaxially press against the center portion  120  by. pressing into the center portion  120  into the central hole  111  of the tempered glass layer  11 . The inward pressing force of the pressing head  21  increases the tension of the peripheral portion  123  of the protection layer  12 . Also, since the bottom surface  122  of the protection layer  12  may also provided with adhesive layer, the inward pressing force of the pressing head  21  will further press the peripheral portion  123  of the protection layer  12  to extend and attach to the upper edge of the central hole  111  of the tempered glass layer  11 . 
     Then, in the step (g-2), a rotating sand wheel is used to grind at the position of the corresponding upper edge of the central hole  111  so as to reduce the thickness of the peripheral edge of the center portion  120  until the center portion  120  of the protection layer  12  is separated from the protection layer  12  to form a center hole  121  coaxially aligned with the central hole  111  of the tempered glass layer  11 . To form the center hole  121  by the pressing and grinding steps in step (g) can, at the same time, substantially eliminate uneven adhering tension of the protection layer  12  to prevent the elongated bubbles popping up between the tempered glass layer  11  and the protective layer  12 . 
     Alternatively, since the protection layer  12  is a thin film and most of the tempered glass layers  11  to be used to make the patio tabletop glass contain decorative patterns on the surfaces, as shown in FIG. 4, in order to ensure the protection layer  12  being completely attached on the tempered glass layer  11  under even tension, the step (e-3) can be modified to use a pair of hard rollers  21 ″,  22 ″ to substitute the pair of rubber rollers  21 ,  22 . However, a pressure board  30 , such as a cardboard or a soft pad made of foam or rubber material having a thickness of about 2 mm, should be placed on top of the protection layer  12  before feeding between the pair of hard rollers  21 ″,  22 ″, wherein the pressure board  30  can not only protect the protection layer  12  but also transfer the greater pressing force applied by the hard rollers  21 ″,  22 ″ to even pressure for attaching the protection layer  12  on the tempered glass layer  11 . 
     In view of above, when the patio tabletop glass  10  is broken into pieces and particles, the top surfaces of each of the broken glass pieces and particles will still be individually attached to the protection layer  12  so as to prevent the broken glass pieces and particles from breaking apart and falling down. In other words, the present invention provides an effective way to solve the conventional glass breaking problem. Moreover, the manufacturing process of the patio tabletop glass is fast and inexpensive and adapted for mass production.