Technical Field

The present invention relates to festoon apparatus for accumulating and dispensing elongated bead material and to methods of operating such apparatus.

Background Art Many types of vehicular tires include beads surrounding the openings which engage the wheel rim. In general, beads comprise a wire coil in the nature of a hoop formed by winding multiple turns of a coated wire on suitable bead forming apparatus. The bead may be made up of multiple, radially and axially arranged turns of a single wire or, in so-called weftless beads, of radially stacked layers of a flat ribbon including a plurality of side-by-side wires. In any case, the single or multiple wires are pulled from one or more supply reels and passed through extrusion die apparatus which applies a coating of rubber or rubberized material to the wire(s) .

The coated wire or ribbon is supplied to conventional bead forming apparatus wherein one or more beads are wound to the desired dimensions and cross-sectional configuration. The forming apparatus accelerates and decelerates during operation and is stopped as the completed beads are removed. Thus, withdrawal of bead material is intermittent and varies in speed. It is desirable that the coating operation be carried out on wire(s) moving continuously at a constant axial speed. Therefore, some means of accumulating the bead material at a position between the coating operation and the bead forming apparatus are required. Such means are commonly provided in the form of two sets of sheaves or pulleys, mounted upon respective axles for independent rotation, about which the bead material is passed. The two sheave assemblies are mounted upon suitable support means, usually in vertically disposed relation, for relative movement toward and away from one another as the bead material is dispensed faster and slower, respectively, than it

is accumulated. Most commonly, the upper set of sheaves is fixedly supported at a position several meters above floor level and the lower set is vertically movable with respect thereto, although in the arrangement of U.S. Patent No. 4,058,265 the lower assembly remains stationary as the upper assembly is moved vertically by a motor. In the usual arrangement, the lower set of sheaves descends by gravity, additional weight often being provided to ensure that proper tension is maintained during such movement. When the festoon is empty, the lower set of sheaves is elevated to a position immediately below the upper set as an operator threads bead material through the two sets of sheaves while standing on a ladder or platform, often two or three meters above floor level.

In order to ensure uniform operation of the bead forming apparatus, it is desirable to maintain a constant, predetermined tension in the bead material as it is withdrawn from the festoon. It is difficult to maintain constant tension as the forming apparatus accelerates, decelerates, stops and starts. Although vertical movement of the lower sheave assembly is normally controlled only by gravity, power-assist means have been provided, as in the case of U.S. Patent No. 4,186,861.

Objects Of The Invention It is a principal object of the present invention to provide novel and improved means for maintaining essentially constant the tension in wire being dispensed from a festoon during relative vertical movement of two sets of sheaves in tire bead material festoon apparatus.

Another object is to provide tire bead festoon apparatus having a vertically movable lower sheave assembly and including means permitting an operator standing at floor level may thread bead material through both upper and lower sheave assemblies.

A further object is to provide a novel method of manipulating elements of tire bead material festoon apparatus to permit threading the material through two sets of sheaves by an operator at floor level.

Other objects will in part be obvious and will in part appear hereinafter.

Disclosure Of Invention The festoon apparatus of the present invention includes the usual first and second sets of sheaves mounted in side-by-side relation for independent rotation upon respective, first and second axles. The two sets of sheaves or sheave assemblies are mounted one above the other, upon a vertical support column and extend perpendicularly therefrom to respective, free ends with the axles in a common vertical plane. Both the upper and lower sheave assemblies are mounted for vertical movement upon the support column. The mounting means for the upper sheave assembly includes a selectively releasable mechanical latch for supporting the sheave assembly at or near the upper end of the support column. The mounting means for the lower sheave assembly permits free travel thereof along the vertical support column between a lower position, a short distance above floor level, and an upper position directly beneath and in contact with the mounting means for the upper sheave assembly to support the latter independently of the mechanical latch.

A pneumatic cylinder is also mounted upon and parallel to the vertical support column. The cylinder is of the type having a movable piston with opposite ends of a cable connected to the upper and lower sides. The cable passes in sealed relation through opposite ends of the cylinder, around suitable pulleys, and is fixedly connected to the lower sheave assembly mounting means. A pressurized air supply is connected to opposite ends of the cylinder and, as bead material is supplied to and withdrawn from the festoon, pressure on opposite sides of the piston is maintained substantially equal by a pilot operated regulator with a feedback pilot. Thus, while vertical movement of the lower sheave assembly is affected by the rates of bead material supply and withdrawal, as well as gravitational effects, the rate of movement is limited by operation of the pneumatic cylinder to maintain equal pressure on opposite sides of the piston. This arrangement serves to maintain substantially constant tension in the bead material pulled from the festoon by the bead forming apparatus.

The cylinder may be operated manually when bead material is

to be threaded on the sheaves of the two assemblies. Pressurized air is supplied to the upper end of the cylinder to move the piston downwardly, thereby moving the lower sheave assembly upwardly until it contacts and supports the upper sheave assembly independently of the mechanical latch. The operator then actuates a switch to move a rotatable latch member to the open position by a small pneumatic cylinder with a conventional operating rod.

Pressure is then reduced in the main operating cylinder to allow the two sheave assemblies to move downwardly, the upper assembly remaining supported by the lower assembly, to a fully lowered position wherein both assemblies are accessible to and threadable by an operator at floor level. After the bead material is threaded on the sheave assemblies, pressure is again applied to the upper side of the piston to raise the lower sheave assembly, and with it the upper sheave assembly, to the fully raised position. The latch mechanism is again actuated to support the upper sheave assembly and normal operation, with pressure regulated by the feedback system, may resume. Brief Description Of The Drawings

Figure 1 is a diagrammatic illustration of the complete operation from removal of wire from a supply reel to the forming thereof into a tire bead, including the festoon apparatus of the present invention; Figure 2 is a top plan view of the festoon apparatus;

Figures 3 and 4 are front and side elevational views, respectively, of the festoon apparatus with the upper and lower sheave assemblies in their uppermost and lowermost positions, respectively; Figure 5 is a schematic illustration of pneumatic elements associated with operation of the invention;

Figures 6 and 7 are front and side elevational views, respectively, showing both sheave assemblies in the upper position; Figure 8 is an enlarged, fragmentary, partly schematic, side elevational view of the upper end of the festoon apparatus showing elements of a latch mechanism in a first position;

Figure 9 is the view of Figure 8, showing the latch elements in a second position; and

Figures 10 and 11 are front and side elevational views, respectively, of the festoon apparatus showing the sheave assemblies in the lower position and, in phantom lines in Figure 11, the upper position.

Modes For Carrying Out The Invention Referring now to the drawings, in Figure 1 is shown a diagrammatic representation of a typical tire bead making operation. Reference numeral 10 denotes a supply of steel wire 12 to which a rubberized coating is applied by conventional die apparatus 14. Wire 12 is pulled through die 14 and fed to festoon apparatus 16 by drum 18. A source of pressurized air 20 is connected to festoon apparatus 16 for reasons explained later. Coated wire bead material 24 is pulled from festoon apparatus 16 by conventional bead forming apparatus 26 which winds the material into hoop-like beads of desired dimensions and cross- sectional configuration, passing over idler drum or sheave 22. In order that the coating material be applied to wire 12 (which may, of course, be a plurality of wires in parallel, side- by-side relation) consistently and uniformly, it is preferred that the speed of axial travel of the wire remain constant. Although the speed may be set at any of two or more levels, there should be no sudden accelerations or decelerations. Operation of bead forming apparatus 26 is, on the other hand, intermittent in nature. As the bead material is wound to its final configuration, the equipment typically accelerates, decelerates, and stops to permit withdrawal of finished beads. Thus, festoon apparatus 16 is provided to receive bead material from the coating operation at an essentially constant rate of speed and supply material to forming apparatus 26 at intermittent times and variable rates. It is further desirable that tension in bead material 24, as it leaves festoon apparatus 16 and is supplied to forming apparatus 26, remain at a substantially constant, predetermined value.

Referring now to Figures 2-4, festoon apparatus 16 is shown with upper sheave assembly 28, comprising a plurality of first

sheaves 30 mounted for independent rotation upon first axle 32, in its uppermost position and lower sheave assembly 34, comprising second sheaves 36 independently rotatable on second axle 38, shown in solid lines in its lowermost position and in phantom lines in an intermediate, operating position. Elongated support column 40 is vertically disposed between upper end 42 and lower end 44, essentially at floor level. Assemblies 28 and 34 are each mounted upon support column 40 for independent, vertical movement thereon by first and second mounting means 48 and 50, respectively. In the illustrated embodiment, powered supply drum 18 is also fixedly supported on plate 46.

Upper sheave assembly 28 is shown in Figures 2-4 releasably retained in its uppermost position, typically two to three meters above floor level, by a pair of identical latch mechanisms 52 and 54, on opposite sides of support column 40 near upper end 42 thereof. Lower sheave assembly 34, on the other hand, is freely movable between its lowermost position, where mounting means 50 rest upon a suitable, fixed stop on support column 40, and an uppermost position, shown in Figures 6 and 7, directly beneath upper sheave assembly 28 with mounting means 50 contacting mounting means 48.

Pneumatic cylinder 56 is fixedly mounted upon support column 40 by plates 58. Cylinder 56 is of the type known as a cable cylinder wherein cable 60 is fixedly connected at opposite ends to upper and lower sides, respectively, of piston 62 within the cylinder and passes through openings, in sealing engagement therewith, in the upper and lower ends of the cylinder. Cable 60 passes around and/or through guide means 64 and 66 at the upper and lower ends, respectively, of the cylinder and is fixedly attached to second mounting means 50. As seen in Figure 4, pressurized air source 20 is connected through fittings 68 and 70 to the upper and lower ends, respectively, of cylinder 40.

During normal operation of festoon apparatus 16, as bead material is supplied to and withdrawn therefrom, pressure on the upper and lower sides of piston 62 is substantially equalized through the operation of valves 72, under the control of pilot operated regulator 74 and associated feedback pilot regulator 76.

These elements are shown diagrammatically in Figure 4, and schematically in the pneumatic flow diagram of Figure 5. Feedback pilot 76 is connected by sensing line 78 to the supply/output air side, and by pilot output line 80 to the relief flow side of regulator 74. For optimum operation, sensing (feedback) line 78 should be connected as close to the cylinder port as possible. Pneumatic components suitable for use in the present invention are available from CA. Norgren Company of Littleton, Colorado, U.S.A. As the festoon fills and empties bead material, the appropriate up (72a) or down (72b) directional control valve is actuated, maintaining the predetermined pneumatic pressure, which is directly proportional to tension in bead material 24, within cylinder 40.

In order to thread a fresh supply of bead material upon festoon apparatus 16, it is necessary to position sheave assemblies 28 and 34 immediately adjacent one another. According to the present invention, when the festoon is empty, an operator may manually control the pressure supply valve to provide pressure to the upper end of cylinder 40, moving piston 62 downwardly and lower sheave assembly upwardly. This movement is continued until mounting means 50 contacts mounting means 48 and supports upper sheave assembly 28 independently of latch mechanisms 52 and 54, as shown in Figures 6 and 7.

Latch mechanism 52 is shown in more detail in Figures 8 and 9. Latch member 84 is pivotally mounted by pin 86 upon a portion of support column 40. Rod 88 is fixedly connected to and extends outwardly from column 40. Small pneumatic cylinder 94 is connected by operating rod 96 to one side of latch member 84. A manually operable switch for operating a control valve, diagrammatically indicated at 98 in Figure 8, is accessible to an operator at floor level to cause cylinder 94 to rotate latch member 84.

In the position of Figure 8, one end of each of latch members 84 extends under projecting shoulders 100 of mounting means 48, thus supporting upper sheave assembly 28 in its uppermost position. Clockwise rotation of latch member 84 is prevented by rod 88. After movement of lower sheave assembly 34

to the position of Figure 9, the pneumatic pressure in cylinder 60 supports both sheave assemblies with shoulders 100 spaced above latch members 84. The operator actuates valve 98 to cause cylinder 94 to retract rod 96 and rotate latch member 84 counterclockwise. Latch mechanism 54 is, of course, simultaneously operated in the same manner.

The pressure in cylinder 60 is then controlled to permit downward movement of lower sheave assembly 34, with upper sheave assembly 28 supported thereon, until the sheave assemblies reach the positions shown in solid lines in Figures 10 and 11, where the sheaves may be threaded by an operator standing at floor level. When the threading operation is completed, cylinder 60 is again pressurized to move the sheave assemblies upwardly until assembly 28 is in its uppermost position, as shown in phantom lines in Figure 11. Latch mechanisms 52 and 54 are actuated to rotate latch members 84 clockwise to support the upper sheave assembly and normal operation resumes.

Appropriate sensors and proximity switches may be mounted in conventional fashion upon column 40 to slow and/or stop operation of feed drum 18 or forming apparatus 26 in order to prevent excessive upward and downward travel of lower sheave assembly 34.