Three wheel stitching apparatus

An apparatus for stitching the components of a pneumatic tire consisting of a left and right hand assembly both of which are capable of arcuate displacement toward and away from each other. Each assembly includes an arm having a rolling device or stitcher wheel thereon for engaging the material that is being consolidated in building the tire body. The arm of one of the assemblies has mounted thereon, as a slave member, a third arm which carries a different type of stitcher wheel for engaging and stitching the center area of the superimposed belts or plys of the pneumatic tire prior to the engagement of the body by the other stitcher wheels.

BACKGROUND OF THE INVENTION 
When sheets of rubberized fabric are being assembled, such as during the 
building of tires, it is necessary to bring the tacky surfaces of said 
sheets into intimate contact and to work out entrained air by rolling the 
surface with a narrow rolling device commonly referred to as a stitcher. A 
stitching apparatus of the foregoing type is illustrated in Applicant's 
prior U.S. Pat. No. 4,057,455 dated Nov. 8, 1977. 
The rolling devices or stitcher wheels are normally rounded at the point of 
contact with the rubberized sheets so that with the stitcher wheels 
engaging said sheets and moving outwardly in opposite directions toward 
the tire edge there remains a central area that is not engaged by said 
wheels. The prior art does teach the concept of multi-wheel stitchers but 
such devices are of the static type having three or more wheels. The 
patents to Thorpe et al U.S. Pat. No. 1,721,842 dated July 23, 1929 and 
Caretta U.S. Pat. No. 3,819,449 dated June 25, 1974 and Takasuge U.S. Pat. 
No. 4,004,961 dated Jan. 25, 1977 are illustrative of such prior art 
devices. In many instances the multi-wheel stitchers of the prior art are 
arranged to progressively engage the tread component of a tire with the 
various wheels and such engagement tends to produce trapped air pockets 
due to such intermittent engagement. In certain prior devices the stitcher 
wheels are not capable of stitching tire components other than the tread 
portion. 
In an attempt to overcome the shortcomings of known stitcher assemblies, 
and particularly as concerns the center portion or area of a tire, 
specifications were devised calling for a manual stitching operation at 
the center section of a tire. Such a concept is not only time consuming, 
but it is a laborious task that is not uniform at all times, especially as 
concerns the degree of manual pressure applied, thus, quite often a poorly 
produced stitchout is obtained at the center portion or area of the tire. 
SUMMARY OF THE INVENTION 
The present invention is directed to a stitching apparatus comprising a 
lefthand assembly and a righthand assembly said assemblies being 
interacting and each said assembly including an arm and a rolling device 
that is adapted to engage the tire. In addition, the arms of one of the 
assemblies has mounted thereon a third arm having a center stitch 
mechanism with the third arm acting as a slave member but being capable of 
movement independently of the movement of either of the assemblies. 
In the stitching apparatus of the present invention, when stitching is 
initiated, the third arm assembly or center stitcher advances towards and 
engages the center area of the tire. This center area of the tire is 
effectively stitched for a period of time after which the center stitcher 
is retracted and the left and right hand stitcher arm assemblies advance 
and engage the tire and undertake the stitching of the tire in the 
conventional manner. Thus, the present invention the entire tread and 
shoulder surface of the tire is stitched which includes the central area 
that is not covered or engaged by the wheels of the left and right hand 
assemblies. 
It is to be further noted that in the present concept the stitcher wheels 
contact the surface or area to be stitched in a sequential manner. That is 
the center area is stitched first by a single stitcher wheel which is then 
withdrawn. The two remaining stitcher wheels then make contact and overlap 
to a degree the path of the first stitcher wheel and continue to carry out 
the remainder of the stitching operation. In this manner any bubbles 
present are progressively worked to the outer extremities and thus to the 
atmosphere.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the drawings there is shown in FIGS. 1 and 2 a stitching 
apparatus including a rectangular shaped support member 10 having a base 
12 mounted thereon by guide and clamp members 14. The support member 10 is 
provided with a bearing 16 having a thrust bearing 18 for receiving an 
adjusting screw 20 which engages a threaded boss 22 mounted on the base 
12. The adjusting screw 20 is also provided with suitable nuts 24 for 
retaining said screw 20 in locked position with respect to the thrust 
bearing 18. 
The base 12 has mounted thereon a suitable motor and housing 26 with a 
drive shaft 28 projecting therefrom upon which is mounted a suitable drive 
sprocket, not shown. The base 12 also has mounted thereon a gear box 30 
that is provided with a planetary gear train of conventional design, not 
shown. The gear box 30 has projecting from an end thereof a drive shaft 32 
which is provided with a sprocket gear 34 having mounted thereon a 
sprocket chain 36. The sprocket chain 36 is entrained about the drive 
sprocket mounted upon the shaft 28 projecting from the motor housing 26. 
The gear box 30 has projecting from the other end thereof a drive shaft 38 
that is provided with a sprocket 40 having a chain 42 for driving a 
sprocket 44 which in turn drives a cam shaft 46 having a plurality of 
micro switches 48 associated therewith. 
The gear box 30 has projecting upwardly from the top thereof a shaft 50 and 
a concentrically disposed sleeve 52 which are rotatably driven in 
contra-relationship with one another by the planetary gear drive in the 
gear box 30. The shaft 50 and sleeve 52 are capable of being rotated in a 
clockwise direction as well as in a counterclockwise direction. The shaft 
50 and sleeve 52 each have affixed thereto a stitcher arm carriage 54 
which is provided with a pair of spaced arms 55 that have mounted in the 
ends thereof a support rod 56 upon which is pivotally mounted a stitcher 
arm 58. The stitcher arms 58 adjacent their lower ends are formed with 
enlarged bosses 60 that are positioned on the support rods 56 intermediate 
the arms 55 and are capable of pivoting about said support rods 56. The 
upper ends of the stitcher arms 58 are provided with stub shafts 62 that 
have mounted on the inner ends thereof conventional stitcher wheels 64 
with spacer collars 66 being positioned between said stitcher wheels and 
said arms 58. 
The arms 55 of each of the stitcher arm carriages 54 are formed with 
angular projections or extensions 68 that have mounted there between an 
air cylinder 70. The cylinder 70 has projecting from an end thereof a 
piston rod 72 which has mounted thereon a clevis 74 that in turn engages 
the lower end of the stitcher arm 58 to pivot same about the support rod 
56. 
As illustrated in FIG. 1 and FIG. 2 one of the stitcher arms 58 has mounted 
thereon, as a slave member, a cylinder 76 with a piston rod 78 projecting 
therefrom which is connected to a clevis 80. The clevis 80 is connected to 
an end of an arm 82 which is secured to an end portion of a shaft 84 that 
has a carriage member 86 affixed thereto. The carriage member 86 has a 
stitcher arm 88 connected thereto with a relatively thick and enlarged 
stitcher wheel 90 rotatably mounted on the free end thereof. 
In the use of the stitching apparatus of the present invention the motor in 
the housing 26 will, through the sprockets and sprocket chain 36, drive 
the shaft 32 and, in turn, the planetary gears in the gear box 30. The 
rotation of the shaft 50 and sleeve 52 will be under the control of the 
micro switches 48 as will the movement of the stitcher arms 58 towards and 
away from the tire carcass 92 positioned upon a tire building drum 94. 
After a belt or ply has been placed upon the tire carcass 92, in the 
customary manner of building a tire, the air cylinder 76 is brought into 
operation for actuating the piston rod 78 and clevis 80 and thus moving 
the stitcher arm 88 and stitcher wheel 90 into engagement with the tire 
carcass. 
The stitcher wheel 90 is of a width greater than the combined width of the 
pair of stitcher wheels 64 and said stitcher wheel 90 has somewhat of a 
flat peripheral surface designed to engage the center section of the tire 
carcass, FIG. 3A. The movement of the third stitcher wheel 90 into 
engagement with the center portion of the tire carcass, while the stitcher 
wheels 64 are retained in an inoperative state, enables the central 
portion or area of the tire carcass to be thoroughly stitched under 
constant and uniform pressure. This insures that the central area or 
segment of the belt or ply is in firm engagement with the previously 
applied belt or ply of the tire carcass. After the stitcher wheel 90 has 
completed its stitching operation the piston rod 78 is retracted into the 
cylinder 76 which results in the retraction of the stitcher arm 88 and 
stitcher wheel 90 to the position shown in FIGS. 1 and 4. 
Upon the retraction of the stitcher wheel 90 to its inoperative position of 
FIGS. 1 and 4 said stitcher wheel 90 becomes a slave member as the 
stitcher arms 58 are actuated by the pistons 72 of cylinders 70 to wherein 
the stitcher wheels 64 engage the tire carcass 92, FIGS. 4 and 4A. As the 
stitcher wheels 64 move in and engage the tire carcass, they overlap a 
portion of the area of the tire carcass that was stitched by the wheel 90, 
FIG. 4A, and the stitcher wheels 64 proceed to stitch the tire carcass in 
the customary manner, such as illustrated in FIG. 5A. The advancement and 
retraction of the third stitcher wheel 90 prior to the actuation of the 
stitcher wheels 64 insures the carrying out of separate and independent 
stitching operations with the stitching wheels 64 overlapping a portion of 
the area previously stitched by the stitcher wheel 90. 
Although the foregoing description is necessarily of a detailed character, 
in order that the invention may be completely set forth, it is to be 
understood that the specific terminology is not intended to be restrictive 
or confining, and that various rearrangements of parts and modifications 
of detail may be resorted to without departing from the scope or spirit of 
the invention as herein claimed.