Tooling and method for joining a heel pad to a floor mat

A tool for vibrationally joining a heel pad to a floor mat includes a platen having a first region and a second region. A first plurality of pins may extend from the first region of the platen, and a second plurality of pins may extend from the second region of the platen. The first plurality of pins are arranged non-parallel to the second plurality of pins. The method of joining a heel pad to a floor mat includes applying a glue between the heel pad and the floor mat, and thereafter vibrationally welding the heel pad and floor mat such that a perimeter region of the heel pad is recessed lower than an interior region of the heel pad. In another aspect of the subject invention, a perimeter region of a heel pad may be joined to a floor mat includes ultrasonically welding a portion of the perimeter or rim region of the heel pad to the floor mat, and thereafter ultrasonically welding the remaining portion of the perimeter region of the heel pad to the floor mat.

BACKGROUND 
1. Technical Field 
The present invention generally relates to floor mats for use in 
automobiles and other motor vehicles. More particularly, the present 
invention relates to removable accessory mats designed to overlie and 
protect carpeted automobile floors. 
2. Background Information 
Floor mats of the "throw-in" or accessory type are widely employed to 
protect the carpeted floors of automobiles and other vehicles. These mats 
are generally manufactured with a planar configuration and are usually 
formed from a material sufficiently flexible to conform in a general way 
to the multiplicity of shapes and contours characteristic of automobile 
floors. 
A problem associated with automobile floor mats is their tendency to wear 
in certain "high use" areas, e.g., where the driver's feet are usually 
stationed. Specifically, a floor mat located on the driver's side of an 
automobile tends to wear more extensively near the gas pedal. Because of 
the extended wear in these "high use" areas, it is common to attach what 
is known as a heel pad to the floor mat. Because heel pads need to 
withstand extensive wear and tear, they preferably are constructed of a 
woven heavy-weight carpet with an appropriate backing. 
Since the heel pad is separately formed from the floor mat, the heel pad 
and floor mat must be joined together. The conventional technique used to 
join heel pads to floor mats is through the use of a hot melt adhesive 
film or glue, together with processing through a heat tunnel. However, 
while this technique can be used with materials having high melting 
points, such as nylon, the heat tunnel technique cannot be successfully 
employed with heel pads and floor mats made from materials having lower 
melting point temperatures, like polypropylene. The temperatures required 
in the heat tunnel technique tend to melt the polypropylene material, 
thereby resulting in the unsightly distortion of the accessory mat. 
However, under certain circumstances, it is desirable to fabricate floor 
mats and heel pads from such materials. One desirable reason to use 
polypropylene is to offer a recyclable accessory mat. 
Moreover, the conventional technique of the heat tunnel is unable to 
produce a joined heel pad and floor mat having a perimeter region of the 
heel pad made flush (or recessed in relation) to the upper surface of the 
floor mat. Therefore, the edges of a resulting heel pad sit above the 
floor mat, and are exposed for contact with the driver's feet. In 
addition, the heat tunnel method also does not always result in a 
sufficient bond between the heel pad and floor mat, and the edges of the 
heel pad may peel away from the floor mat and result in fraying and 
unraveling. Therefore, it may be necessary to "rim seal" the perimeter 
region of the nylon heel pads to the floor mats. The conventional method 
for rim sealing the perimeter region is by way of a radio frequency (RF) 
welding technique. By rim sealing the perimeter region by RF welding, a 
greater bond can be achieved between the heel pad and floor mat, and the 
edges of the heel pad can be recessed into the floor mat so that the 
interior region of the heel pad can be made flush to the upper surface of 
the floor mat. RF welding, however, cannot be employed with materials 
having low melting point temperatures, such as polypropylene, again 
because of the melting of the material and unsightly distortion thereof. 
Also, where RF welding is appropriate, such as with nylon materials, a 
channel is formed about the peripheral edge of the heel pad, which may not 
always be desirable. 
Thus, a need exists for a new tool and method for joining heel pads to 
floor mats, which can be effectively used on floor mats and heel pads 
constructed from materials having low melting point temperatures. The 
structure and method of the present invention presents a solution to the 
aforementioned problems. 
SUMMARY OF THE INVENTION 
Briefly, the present invention satisfies this need and overcomes the 
shortcomings of the prior art through the provision of tooling and a 
method for joining a heel pad to a floor mat. The tool of the subject 
invention includes a platen having a first region and a second region. A 
first plurality of pins may extend from the first region of the platen, 
and a second plurality of pins may extend from the second region of the 
platen. The first plurality of pins are arranged to be non-parallel to the 
second plurality of pins. 
The method of the subject invention for joining a heel pad to a floor mat 
includes applying a glue between the heel pad and the floor mat, and 
thereafter vibrationally welding the heel pad and floor mat such that a 
perimeter region of the heel pad may be even with or recessed lower than 
an interior region of the heel pad. 
Another aspect of the present invention is a method for joining a perimeter 
region of a heel pad to a floor mat, which includes ultrasonically welding 
a portion of the perimeter region of the heel pad to the floor mat, and 
thereafter ultrasonically welding the remaining portion of the perimeter 
region of the heel pad to the floor mat. 
It is therefore a primary object of the present invention to provide a new 
and improved tool and method for joining a heel pad to a floor mat. 
It is yet another object of the present invention to provide a tool and 
method for vibrationally welding a heel pad to a floor mat. 
It is another object of the present invention to provide a method which is 
applicable to materials having low melting point temperatures, such as 
polypropylene. 
It is still another object of the present invention to provide a 
combination heel pad and floor mat which results in an aesthetically 
pleasing accessory mat. 
It is yet another object of the present invention to provide a joined heel 
pad and floor mat which is exceptionally durable and which results in a 
high peel strength for the resultant accessory mat. 
It is yet another object of the present invention to provide a joined heel 
pad and floor mat which can be manufactured at an improved cycle time over 
existing techniques. 
It is still another object of the present invention to provide a tool and 
method for joining a heel pad to a floor mat which reduces manufacturing 
costs over existing techniques. 
It is also an object of the present invention to provide an ultrasonic 
welding method for joining a perimeter or rim region of a heel pad to 
floor mat. 
It is a further object of the present invention to provide a method for 
joining a perimeter region of heel pads and floor mats constructed from 
polypropylene.

DESCRIPTION 
It will be readily apparent that the components and steps of the present 
invention, as generally described and illustrated in the figures, could be 
arranged and designed in a wide variety of different configurations. Thus, 
the following detailed description of the presently preferred embodiments 
of the tooling and method for joining a heel pad to a floor mat of the 
present invention, as represented in FIGS. 1-9, is not intended to limit 
the scope of the invention, as claimed, but is merely representative of 
the presently preferred embodiments of the invention. The presently 
preferred embodiments of the invention will be best understood by 
reference to the drawings, where like parts are designated with like 
numerals. 
A floor mat typically comprises several layers of different materials. For 
example, the floor mat for which the tooling and method as defined herein 
may be employed includes a first layer of polypropylene carpet fibers, 
which are tufted into a polypropylene scrim. Coated to the underside of 
the scrim may be a layer of latex. A final backing layer may be a 
polypropylene thermoplastic olefin ("TPO"). Similarly, a heel pad may 
include various different layers, e.g., a layer of polypropylene carpet 
fibers tufted into a polypropylene scrim, with a latex coating applied to 
the underside of the scrim. It should be known that other materials are 
also suitable for use in the subject invention, including nylon. 
In reference to the drawings, and more particularly to FIGS. 1 & 2, there 
is shown in accordance with the principles of the present invention, one 
embodiment of a tool 10 used for vibrationally welding a heel pad to a 
floor mat. As can be best seen from the plan view of FIG. 1A, tool 10 may 
include a platen 12 divided into two regions, a first region 14, e.g., a 
perimeter region, and a second region 16, e.g., an interior region. A 
border 15 delineates perimeter region 14 from interior region 16. 
FIG. 1A also displays an array of pins which extend away from platen 12. 
More specifically, a first plurality of pins 18 may extend away from 
perimeter region 14 of platen 12 and a second plurality of pins 20 may 
extend away from said interior region 16 of platen 12. In the preferred 
embodiment, pins 18 and 20 are of equal length and are spaced equally on 
their respective regions. As described more fully hereinafter, it is the 
unique configuration and positioning of these pins which forms a 
significant aspect of the subject invention. 
As can be seen in FIG. 1B, in the preferred embodiment, tool 10 comprises 
five separate components or sections. As depicted in FIG. 1B, these five 
sections include a central member which forms interior region 16, and four 
outer sections which form perimeter region 14. Therefore, perimeter region 
14 may comprise a first section 22, a second section 24, a third section 
26 and a fourth section 28. By way of conventional methods of attachment, 
each of the four outer sections and interior region 16 can be attached 
together to form tool 10. Preferably, the five components or sections are 
mounted to an aluminum block. 
In the preferred embodiment, first region 14 extends around the perimeter 
of platen 12, and second region 16 may be disposed within first region 14. 
Therefore, second region 16 may be surrounded by first region 14. 
Preferably, interior region 16 is a flat planar surface, centrally located 
on platen 12. 
As illustrated in FIGS. 2 and 3, first region 14 is skewed in relation to 
second region 16, thus providing a sloped configuration about the 
perimeter of platen 12. In the preferred embodiment (see FIG. 3), an angle 
of 175 degrees is formed between the planar surface of perimeter region 14 
and the planar surface interior region 16. Therefore, there is a skew 
angle (.theta.) of 5 degrees between perimeter region 14 and inner region 
16. 
It should be understood that other degrees of skew may be employed in the 
subject invention, and the invention is in no way limited to the 5 degrees 
described above. Depending upon the nature and characteristic of the weld 
desired, it may be advantageous to provide a skew greater or less than 5 
degrees. Therefore, the angle formed between the planar surface of 
perimeter region 14 and the planar surface interior region 16 may be less 
than 180 degrees. The specific skew ultimately selected will depend on a 
variety of characteristics, including, for example, the degree of recess 
desired for the perimeter region of the heel pad into the floor mat. 
Because tool 10 is employed for joining a heel pad to a floor mat, platen 
12 should correspond to the shape of the specific heel pad desired to be 
joined to the floor mat. As shown best in FIG. 1A & 1B, tool 10 is 
rectangular in shape to correspond to a heel pad which also is rectangular 
in shape. However, the actual shape of tool 10 will depend upon the 
desired shape for the heel pad, which can take a variety of different 
shapes and forms. 
As for the specific tool described in the subject application, tool 10 is 
preferably employed such that perimeter pins 18 and interior pins 20 face 
downward during operation (see FIG. 6). When viewing the side of tool 10 
having pins 18 and 20 projecting from platen 12, as shown in FIG. 1A, 
first region 14 and second region 16 resembles a "pool-like" structure, 
which includes four sloping side walls. Sections 22, 24, 26 and 28 
represent the side walls of the "pool-like" structure (see FIG. 1B). 
First plurality of pins 18 extend away from first region 14 and second 
plurality of pins 20 extend away from second region 16. Because of their 
location on separate regions of platen 12, first plurality of pins 18 may 
be referred to as "perimeter" pins 18 throughout this specification, while 
second plurality of pins 20 may be referred to as "interior" pins 20. Pins 
18 and 20 may be fabricated from hardened A2 tool steel. 
As can be seen best in FIG. 3, each perimeter pin 18 is preferably angled 
or tilted outward towards its respective outer edge of first region 14. 
For example, pins 18 extending from side section 22 (FIG. 1B) of perimeter 
region 14 may be tilted towards an outer edge of side section 22. 
Preferably, an angle (.beta.) of 75 degrees may be formed between a 
central longitudinal axis of each perimeter pin 20 and the planar surface 
corresponding to the respective section of the perimeter region 14 from 
which each pin projects. Therefore, each pin is preferably tilted 10 
degrees, from an imaginary axis which runs perpendicular to the planar 
surface of interior region 16. Therefor, an angle (.PHI.) of 10 degrees is 
preferably formed between the vertical axis running perpendicular to the 
planar surface of interior region 16 and the central longitudinal axis of 
each pin 18. 
While a tilt angle of 10 degrees is preferred, it should be noted that the 
present invention is in no way limited to such an angle. Therefore, in 
lieu thereof, the degree of angulation or tilt for each perimeter pin 18 
may be adjusted, depending upon the desired characteristics for the weld 
between the heel pad and floor mat. 
Interior pins 20 are preferably oriented perpendicular to the planar 
surface of interior region 16. Therefore, interior pins 20 may extend 
straight up and are each arranged parallel to one another. Because of the 
tilt of the perimeter pins 18, interior pins 20 are preferably arranged 
nonparallel to perimeter pins 16. Moreover, as described above, each 
perimeter pin 18 is angled or tilted outward towards the edge of its 
respective section. Therefore, for example, each of the pins extending 
from first section 22 are arranged non-parallel to pins extending from 
second surface 24, third surface 26 and fourth surface 28. 
By configuring and orienting the perimeter pins 20 as described above, the 
edge or perimeter region of a heel pad can be set tighter to the floor mat 
in comparison to the interior region. Therefore, the perimeter region of 
the heel pad may be recessed or set slightly lower than the interior 
region. The interior region thus may appear fuller than the perimeter 
region, i.e., the interior region may be elevated to a greater degree than 
the perimeter region of the heel pad. Moreover, by using the tool and 
method as described herein, the heel pad may be joined flush to the floor 
mat. Depending upon aesthetic preferences, the degree of recess for the 
heel pad can be selectively chosen. 
FIGS. 4A & 4B depicts the preferred configuration of each perimeter pin 18. 
Each perimeter pin 18 may have a pin head which includes an upper surface 
30 and four side surfaces, a first side surface 32, a second side surface 
34, a third side surface 36 and a fourth side surface 38. At least one of 
the side surfaces, e.g., side surface 36, is formed at a 45 degree angle 
in relation to the upper surface 30, and at least one of the side 
surfaces, e.g., side surface 32, is formed at a 30 degree angle in 
relation to the upper surface 30. Preferably, the side surface formed at a 
45 degree angle in relation to upper surface 30 is faced inward towards 
interior region 16. Moreover, it is preferred that the side surface formed 
at a 30 degree angle in relation to upper surface 20 is faced outward 
towards the outer edge of perimeter region 14. It should be understood 
that the subject invention is not restricted to the 30 and 45 degree 
parameters, but other values and head configurations may be substituted 
therefor. 
FIGS. 5A & 5B illustrates the preferred configuration of each interior pin 
20. Each interior pin 20 may have a pin head which includes an upper 
surface 40, and four side surfaces 42. Preferably, the four sides surfaces 
42 are angled at 45 degrees in relation to upper surface 40. In lieu of 
the specific pin head configuration described herein, other configurations 
may be equally satisfactory. 
FIG. 6 is a block diagram illustrating an apparatus 50 which is used in 
combination with tool 10 to achieve the joining of a floor mat and heel 
pad, in accordance with the principles of the present invention. As 
illustrated in FIG. 6, a floor mat 52, having its carpeted face up, is 
disposed on a lower fixture 56. Positioned on top of floor mat 52 is a 
heel pad 54, also having its carpet face up. Disposed above heel pad 54 is 
tool 10, together with an upper fixture 58 attached thereto. Typically, an 
operator would place and position floor mat 52 and heel pad 54 on lower 
fixture 56. As illustrated by reference number 57, lower fixture 56 may be 
moved vertically up and down. 
Operationally, an operator positions floor mat 52 and heel pad 54 on lower 
fixture 56 of apparatus 50. Tool 10 is disposed directly above floor mat 
52 and heel pad 54. Lower fixture 56 may then be raised vertically upward 
so as to force tool 10 into contact with heel pad 54. By forcing tool 10 
into contact with heel pad 54, pins 18 and 20 penetrate the layers of heel 
pad 54. The desired amount of pressure may be varied, depending on the 
degree of recess desired for the peripheral boundary of heel pad 54. A 
motive means 60, such as are widely known in conventional vibrational 
welding units, may then be activated to cause tool 10 to vibrate from side 
to side, as depicted by arrow 62. 
Another significant aspect of the subject invention is the use of a 
thermosetting adhesive or heat activated glue between the heel pad and 
floor mat. The adhesive may be employed to join the heel pad and the floor 
mat, wherein the adhesive may be applied to the underside of the heel pad 
by employing conventionally known methods. One preferred adhesive which 
works especially well in the present invention is marketed by BF Goodrich, 
and is known as PL800 adhesive. By penetrating the pins into the scrim 
layer of the heel pad, the vibrational energy melts the adhesive and 
creates the bond between the heel pad and floor mat. 
After engagement of the pins, the vibration of tool 10 activates the 
adhesive, thereby resulting in the joining of the heel pad and floor mat 
together. The configuration of the pins results in the perimeter region of 
the heel pad being recessed below the planar surface of the floor mat. 
In the vibrational welding method of the subject invention, there are four 
controllable parameters, i.e., frequency, amplitude, pressure and time. 
Each of the parameters may be adjusted, depending on the nature of the 
weld sought between the heel pad and floor mat. For example, if a deeper 
recess of the perimeter region of the heel pad into the floor mat is 
desired, greater pressure may be applied. As a example, the parameters may 
be set as follows: (1) frequency--240 hertz; (2) amplitude--70/1000th of 
an inch (35/1000th of an inch in each lateral direction); (3) 
pressure--2,500-3,500 pounds; and (4) time--15 seconds. 
The new tool and vibration method of welding described above can be used to 
join a variety of materials, including polypropylene. While polypropylene 
is the preferred material, other materials may be equally suitable for use 
with the subject invention, e.g., nylon. 
In another aspect of the present invention, a method of ultrasonically 
joining a perimeter region of a heel pad to a floor mat is disclosed, 
which can be employed to accentuate the joint created by vibration 
welding, as described above. In a general sense, ultrasonic welding is a 
process wherein coalescence of the floor mat and heel pad is achieved by 
the localized application of very high frequency vibratory energy to the 
heel pad and floor mat as they are held together under pressure. 
Conventionally known ultrasonic welding apparatuses may be employed in 
this aspect of the present invention. This technique may be described as 
ultrasonic rim sealing of the heel pad to the floor mat. 
FIGS. 7 & 8 illustrate an apparatus 70 which may be employed to 
ultrasonically join the perimeter region of a heel pad to a floor mat. 
Apparatus 70 may include a lower fixture 72 configured for accepting a 
floor mat 74 and a heel pad 76. Located above lower fixture 72 may be a 
horn 78, which is attached to an upper fixture 80. A face plate 82 may be 
attached to horn 78, and a U-shaped section 84 may project away from face 
plate 82, corresponding to a portion of the perimeter region of the heel 
pad sought to be joined, may project away from horn 78. As is known in the 
art, U-shaped section 84 may include a knurled pattern. 
Operationally, floor mat 74 and heel pad 76 may be positioned on lower 
fixture 70 by an operator. Thereafter, horn 78 may be lowered so that 
U-shaped section 84 comes into contact with the perimeter region of heel 
pad 76. After the desired pressure is reached, e.g., 50 pounds, the 
ultrasonic welding apparatus is activated to the specified frequency, 
e.g., 20K hertz, for the specified time, e.g., 6 seconds. The ultrasonic 
vibration welding apparatus has a power rating of at least 2,000 watts. 
Because U-shaped section 84 only corresponds to a portion of the perimeter 
region, preferably one-half of the perimeter region, it is necessary to 
rotate lower fixture 70 so that the remaining portion of the perimeter 
region of heel pad 74 can be sealed to floor mat 76. After the first 
one-half of the heel pad is sealed, horn 78 may be raised and lower 
fixture 70 rotated 180 degrees so that the remaining one-half of the heel 
pad can be joined to the floor mat. After rotation of the heel pad is 
complete, the ultrasonic welding process is repeated. 
The result of employing the ultrasonic welding technique to rim seal heel 
pads to floor mats is to create an aesthetically pleasing perimeter or rim 
region of the heel pad, i.e., a crisp, clean look about the peripheral 
edge of the heel pad. Not only is the impression created about the rim 
aesthetically pleasing, but the seal between the heel pad and floor mat 
may result in a better joint between the heel pad and the floor mat, thus 
further preventing the heel pad edges from peeling or fraying. 
The method of ultrasonically joining or welding a perimeter region of the 
heel pad to the floor mat is preferably performed after vibration welding 
has been completed, as described above. Also, ultrasonic rim sealing is 
preferably employed with materials such as polypropylene, and other 
alternatives having low melting point temperatures. 
While several aspects of the present invention have been described and 
depicted herein, alternative aspects may be effected by those skilled in 
the art to accomplish the same objectives. For example, while the first 
region of the platen is preferably skewed in relation to the second region 
by 5 degrees, other angles of skew may be selected in accordance with the 
principles of the subject invention. Also, while a specific pin head 
configuration is disclosed herein having specific face angles, other face 
angles may also be used in the present invention. Furthermore, while the 
pins described herein are preferably of equal length and spaced equally 
apart from one another, the length of the pins may be modified, as well as 
the density and spacing of the pins. Accordingly, it is intended by the 
appended claims to cover all such alternative aspects as fall within the 
true spirit and scope of the invention.