Pile surface resembling turf and method of making it

A turf-like product suitable for use as a golf tee surface is constructed of artificial turf units which are strung on a plurality of tie rods which are secured at both ends. Each turf unit comprises a number of superimposed layers of a polymeric tape having slits which are transverse to the length of the tape. Holes are programmed in determined frequency along the length of each layer by a heated plunger which passes through the layers of tape. The layers of tape are fused together at the circumference of each hole whereby integrity in the turf unit is obtained. The programmed holes are also used as a mechanical device to construct the pile surface by means of the tie rods. The superimposed layers may be formed by winding the tape on a skein winder.

BACKGROUND OF THE INVENTION 
This invention relates to a product having a turf-like appearance. It also 
concerns a process for manufacturing such a product. 
Man-made products having a turf-like appearance and which can withstand the 
abuse and punishment to which a playing field is subjected are in growing 
demand. A natural turf playing field for football, baseball, golf, soccer, 
and other outdoor games is difficult and costly to keep in functional and 
attractive condition. Bad weather, insects, frequent and severe use, in 
particular, contribute to rapid deterioration of natural turf playing 
fields. One of the most severely abused playing surfaces is a golf tee 
surface. In addition, the condition of the golf tee surface is intimately 
related to both the attainment of a suitable drive shot and to minimizing 
the injury to a player whose golf club impacts the tee surface in an 
undesirable manner. 
SUMMARY OF THE INVENTION 
The present invention provides a product having a turf-like appearance 
which is particularly suitable for use as a golf tee surface. The final 
turf surface is made from a plurality of turf units which are joined by a 
plurality of tie rods. Each unit is made from a tape having a plurality of 
slits extending at least partially across the width of the tape. The slits 
are spaced so that the portion of the tape between two consecutive slits 
resembles a blade of grass. The tape is arranged in superimposed layers to 
form a tape bundle. The layers of superimposed tape within the bundle are 
optionally fused together along one elongated edge. To form the turf unit, 
a plurality of holes are created in the tape bundle along the length of 
each layer by a series of heating element rods so that: a) the holes in 
each layer are in substantial registry with the holes in the other layers 
to form a plurality of series of holes and b) the layers are fused to each 
other at peripheral, marginal areas around each hole. Fusion of the tape 
layers at the holes and at the elongate edges provides integrity to the 
turf unit. The turf units are strung onto tie rods which pass through the 
holes in the tape. 
The present invention also provides a novel process for preparing a product 
having a turf-like appearance. The turf units of the present invention are 
advantageously formed by winding a roll of tape onto a skein winder until 
the skein reaches a desired thickness. The skein is removed, placed in a 
vise, and compressed so as to bring the layers of tape forming the skein 
into close contact. A series of heating element rods are inserted into 
holes which are programmed in the vise holding the skein. The heated rods 
melt their way through the skein creating holes in the skein and fuse the 
layers of tape around the peripheral, marginal areas of the holes. To 
provide additional reinforcement to the turf unit, a hot roll may be 
passed over the tips of the tape (facing up) while the skein is compressed 
in the vise. The skein is removed from the vise and strung on the rods to 
form a surface area of desired dimension. Optionally, after removal from 
the vise, the skein can be cut to a desired length. Preferably, the cut 
end is fused by means of a hot-cutting device. Alternatively, fusing can 
occur in a separate step by means of a vise and hot roller arrangement as 
discussed above. 
Preparation of the turf unit by means of the skein winder is considerably 
more economical, takes less time, and results in a more even turf surface 
than cutting the tape into strips and then superimposing the strips on one 
another. 
OBJECTS OF THE INVENTION 
It is an object of this invention to provide an artificial turf surface 
possessing sufficient integrity to survive the abuse and punishment to 
which a golf tee surface is exposed by the impact of a golf club. 
It is another object of this invention to provide an artificial turf 
surface that has a porosity which permits rain to pass through the turf 
and which permits the insertion of a wooden tee to support a golf ball in 
preparation to hitting the ball. 
Another object of this invention is to construct an artificial turf pile 
surface of sufficient depth to form a cushion to absorb the shock of a 
golf club striking the surface and which permits a free continuing flow of 
a golf club head through the surface, thereby providing a complete flow 
through the swing. 
Still another object of this invention is to provide an artificial turf 
surface which can be made level with the surrounding natural grass turf by 
implantation and which also provides a solid hitting area which will not 
move. 
A further object of this invention is to provide a method for making an 
artificial turf product which fulfills the above objectives in an 
economical and time-saving manner.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The artificial turf surface of the present invention comprises a number of 
artificial turf units 1 which are strung by means of holes 2 onto a 
plurality of rods 3 as shown in FIG. 1. The tie rods 3 are preferably 
either threaded rods or rods which are threaded only at their ends. 
However, unthreaded rods may also be used. Nuts 4 or other appropriate 
fastening means are secured to the ends of the rods for preventing the 
turf units from slipping off of the tie rods and for maintaining the turf 
units tightly compressed together. 
Each turf unit 1 comprises a determined number of layers of specially 
prepared tape. The preferred tape of the present invention is shown in 
FIG. 2. It may be obtained by slitting a woven or knit polymeric fabric 
into strips. The width of the strip (or tape) determines the pile height 
of the artificial turf product. The width of the strips is typically 
between about 3/4" and about 2". The preferred width is about 11/2". The 
strip which is cut from the woven fabric comprises individual grasslike 
portions 5 which are parallel to each other. The portions 5 are woven 
together with thread 6 which runs traverse to the length of the grass-like 
portions 5. 
Optionally and preferably, the tape is processed in a warp-running 
direction through a heating mechanism which fuses the several layers of 
tape on one edge 7 forming a homogenous tape bundle. A plurality of holes 
are programmed in determined frequency by a heated plunger which passes 
successively through the layers of tape. The holes 2 are preferably made 
in an off-center position favoring the bottom edge 7 of the tape. The 
fusion of the layers of tape to one another around the peripheral area 
surrounding each hole develops integrity in the artificial turf unit. 
Likewise, fusion of the tape layers along their bottom edge 7 provides 
additional integrity to the artificial turf unit. 
The woven or knit polymeric fabric used to prepared the tapes of the 
present invention may be a polypropylene fabric which is used for primary 
backing for tufting. When this fabric is cut into strips, the thread 6 
extends across the entire width of the strip (or tape). For creation of 
the grass-like pile surface, the thread 6 is unraveled or otherwise 
removed (as by means of a wire brush) along the length of the tape from 
the top edge 8 of the tape down to the holes 6 thus creating a grass-like 
pile surface. While unraveling of the thread to the holes is preferred, 
unraveling to points intermediate of the upper edge 8 and the holes are 
also contemplated. Additionally, the unraveling of the thread 6 may be 
performed either before or after formation of the holes 2. However, the 
latter procedure is preferred. 
Most preferably, the polymeric fabric from which the tape is cut is woven 
or knit so as to include alternate elongated areas which are woven or knit 
with the thread 6 and open elongated areas which do not include the thread 
6. This fabric is cut into strips (or tape) so as to include one elongated 
threaded area and one elongated unthreaded area. With this type of fabric, 
the tape of FIG. 2 is obtained without the need for unraveling or 
otherwise removing thread from the top edge 8 downwardly as with the tape 
cut from the above-described primary backing. 
While woven tapes are preferred for their greater porosity and flexibility, 
non-woven tapes can be used to form the artificial turf units of the 
present invention. Suitable non-woven tapes are disclosed in U.S. Pat. No. 
3,673,056 to Nadler, (herein incorporated by reference) at col. 3 lines 
3-47 and are shown in FIGS. 3 and 4 of the patent. 
The preferred polymeric material for the tapes (either woven or non-woven) 
used in the present invention is polypropylene. However, other polymeric 
materials, particularly thermoplastic ones, and additives such as those 
disclosed in U.S. Pat. No. 3,673,056 at col. 2 lines 60-69 are suitable. 
The length of an artificial turf unit of the present invention typically 
ranges from six inches to multiples of many feet, depending on the product 
use or the area to be covered. The thickness of the artificial turf unit 
is determined by the number of layers of tape and is typically on the 
order of about 1/8" to about 1.0". The layers of tape forming an 
artificial turf unit can be a continuous piece of tape which is coiled to 
form superimposed layers. The layers can also be individual layers which 
are optionally and preferably fused to each other at their ends 9 and 10. 
According to the process of the present invention, as shown in FIG. 3, a 
single roll of tape 11 is placed on a let-off stand 12 and fed through 
rollers 13 and 14 onto a modified skein winder 15 until the skein 
accumulation reaches a thickness of approximately one inch. The length of 
the skein 16 can range from six inches to multiples of many feet, 
depending on the product use or the desired size. The skein 16 is then 
removed from the skein winder 15 as shown in FIG. 4. The removed skein has 
a bottom elongated end 17 and a top elongated end 18. Both the top and 
bottom ends are formed by the edges where the fabric was cut to form the 
tape. As shown in FIG. 5, the skein 16 is then placed in a vise 19 on end, 
cut end 17 down and cut end 18 facing up. The vise is then closed and the 
skein is compressed. While in this compressed and fixed position in the 
vise, a hot roll 20 is passed over the tips of the tape on top end 18 
fusing top end 18 of the skein into a solid surface. 
While the skein 16 is still in the compressed position, a series of heating 
element rods 21 are inserted into holes 22 which are programmed in the 
vise 19 holding the skein 16. By so doing, the heated rods melt their way 
through the skein 16 creating holes in the skein 16. The skein 16 is 
additionally reinforced by the fusing that occurs in the inner surface 
area 23 of the circular hole 2 as shown in FIG. 6. Where the tape was cut 
from fabric used as primary backing, a portion of the thread 6, must be 
removed. After the skein 16 is released from the vise, the fused end 18 is 
placed down as shown in FIG. 6. The woven thread 6 of the skein 16 is then 
unraveled from the other end 17 down to the fused holes 2 in the skein 16, 
thereby leaving the filler yarn standing up and thus creating a grass-like 
pile surface. 
After accumulating a sufficient number of these prepared skeins 16, they 
are then strung onto threaded rods 3 to form a surface area of a desired 
dimension as shown in FIG. 1. The accumulated skeins are then drawn 
together by placing nuts 4 on the threaded rods 4 thereby locking the 
surface securely. 
After the skein is removed from the vise, it can be cut to a desired 
length, the ends fused, and then strung on the tie rods. By using both 
skeins and tie rods of various lengths or cutting the skeins to various 
lengths, as indicated, a pile surface of non-rectangular configuration can 
be achieved. Final skeins of varying length can be obtained by cutting the 
skein to the desired length after it is removed from the vise and fusing 
both ends of the cut skein from the bottom to the height of the woven 
portion of the skein.