WO2000027616A1

WO2000027616A1 - Tire building drum

Info

Publication number: WO2000027616A1
Application number: PCT/US1999/026815
Authority: WO
Inventors: Gerald H. Randall
Original assignee: Illinois Tool Works, Inc.
Priority date: 1998-11-12
Filing date: 1999-11-12
Publication date: 2000-05-18

Abstract

A tire building drum (10) having a plurality of drum segments (12, 14) which define a cylindrical drum surface (10a) when the segments are moved to an expanded position. A spider (26) that forms part of a rotatable hub (20) is connectable to a drive source. A swing arm hub is carried by the spider hub (20) and is relatively rotatable. The tire drum (10) includes a second spider (40) that is coupled to the first spider (26) with both spiders including radial arms that interconnect certain of the drum segments with the spiders (26, 40). The swing arm includes control links (58, 60) pivotally connected to and interconnected with the segments, such that relative rotation between the swing arm and the spider moves the drum segments (12, 14) in coordinated movement from an expanded position to a radially collapsed position.

Description

Tire Building Drum

Technical Field

The present invention relates generally to tire building and in particular to a tire building drum which collapses to an overall circular configuration. Background Art

Tire building drums are commonly used in the tire industry and are used for construction of the green or unvulcanized tire carcass. A tire building drum generally comprises a cylindrical assembly made up of an array of segments. The drum generally includes a mechanism which causes the segments to move between a expanded position and a collapsed position.

In many prior art drums, the drum segments fold inward to form a shape other than circular when collapsed and as a result it may hinder removal of the green tire. It is desirable, if possible, to have the drum collapse to a substantially circular configuration and to define a substantially reduced diameter from that defined in its expanded position.

Although tire building drums are available which collapse radially to a circular configuration, it is believed these drums are more complex and therefore are difficult to service or are subject to distortion, wear, or other maladies which compromise their usefulness. An example of an existing tire building drum of this type is disclosed in U.S. Patent No. 3,785,894.

Disclosure of Invention

The present invention provides a new and improved tire building drum that utilizes a simple folding action of the type normally found in inertia collapsing tire building drums, but collapses into a substantially circular shape, a feature normally found on a radial collapsing type drum.

According to the invention, the drum comprises an outer shell formed by a plurality of segments or deck sections. When expanded, the plurality of segments fit tightly together in a side-by-side relationship and provide a substantially unbroken cylindrical drum surface or deck. Inboard and outboard spiders, each having a plurality of radial arms, are interconnected to certain of the deck sections. A swing arm hub mounts a plurality of control links which interconnect the swing arm hub with structure on the deck sections. According to the invention, relative rotation between the spiders and the swing arm hub produce contraction and expansion of the tire drum surface depending on direction of rotation.

According to the feature of the invention, the inboard and outboard spiders are coupled together so that they rotate in unison. In the illustrated embodiment, this coupling is achieved by a pair of tie bars which are secured to the spiders. It should be understood that other devices may be used to couple the spiders.

According to another feature of the invention, a positive stop is provided for arresting motion in the swing arm in order to resist further relative rotation between the swing arm and the spiders. This preferably occurs at the point where the control links are in a vertical position or slightly over center.

According to still another feature of the invention, the expanded diameter of the tire drum is maintained through the use of ball detents which act between the spiders and the swing arm.

According to a feature of the illustrated embodiment, access holes are provided in the spiders which enable the removal of pins that hold the control links to the swing arm without requiring disassembly of the drum, as is the case with many prior art drums. This enables the pins and/or the control arms to be replaced without requiring extensive disassembly. To further advance serviceability, a drum lock is provided in the illustrated embodiment which locks the drum in the expanded position by inhibiting relative rotation between the swing arm and spiders.

The disclosed tire building drum is of relatively simple construction, is easy to service and maintain while providing a drum of the type in which the deck sections move inwardly in a radial direction so that a circular periphery is achieved at the collapsed position, facilitating removal of a tire carcass. Additional features will become apparent and a fuller understanding obtained by reading the following detailed description made in connection with the accompanying drawings. Brief Description of Drawings Figure 1 is a side elevational view of a tire building drum constructed in accordance with a preferred embodiment of the invention shown in its expanded position as seen from the plane indicated by the line 1-1 in Figure 2;

Figure 2 is a sectional view of the tire building drum as seen from the plane indicated by the line 2-2 in Figure 1 ;

Figure 3 is side elevational view of the other side of the tire building drum shown in Figure 1 as seen from the plane indicated by the line 3-3 in Figure 2;

Figure 4 is a side elevational view of the tire building drum constructed in accordance with the preferred embodiment of the invention, shown in its collapsed position; and

Figure 5 is a fragmentary, exploded view of a portion of the tire building drum.

Best Mode For Carrying Out The Invention Figure 1 illustrates a tire building drum, indicated generally by the reference character 10, embodying the present invention and which is shown in its "expanded" position. Figure 4 illustrates the tire building drum 10 in its collapsed position. Those in the art will recognize the tire building drum as a device that is used to form the support for the materials that comprise a "green" or unvulcanized tire carcass. The materials are typically wrapped around the expanded drum, and when the tire building process is completed, the tire building drum is collapsed (to the position shown in Figure 4 which allows the tire carcass to be removed. The tire carcass then is further processed i.e. vulcanized to form a finished tire. The drum 10 comprises an outer shell formed by eight segmental portions consisting of four large segments or deck sections 12, alternating respectively with four smaller segments or deck sections 14. In the expanded condition of the drum shown in Figure 1 , the eight segments fit tightly together and provide a substantially unbroken cylindrical drum surface or deck 10a. These segments and the linkage mechanism which interconnects them will be described in detail.

Referring also to Figure 2, the drum 10 includes an inner hub 20 which is adapted to be connected to a suitable drive shaft (not shown) forming part of or coupled to a drive motor (not shown) which provides rotation. The hub

20 may include a keyway 21 for rotatively coupling the hub 20 to the drive shaft. Integrally formed with the hub 20 is an outboard spider 26 having four radial arms 26a. Mounted concentrically with the spider hub 20 is a swing arm hub 30. The swing arm hub 30 includes four lateral lugs 30a that each define a pair of laterally spaced pivot bores for receiving removable pivot pins

34. Bearings 32 disposed between the spider hub 20 and the swing arm hub 30 provides the necessary bearing surface.

A quill 36 is secured by bolts to the swing arm hub 30. The quill 36 can be acted upon by a separate brake mechanism in order to produce relative rotation between the spider hub 20 and the swing arm 30. An inboard spider 40 is rotatably supported on the swing arm hub 30 by a bearing 42. The inboard spider 40 is rigidly coupled to the outboard spider 26 by a pair of tie bars 44, 46 shown in Figures 1 and 3, which are secured to the spiders 26, 40 by bolts 48. The tie bars 44, 46 insure that the spiders 26, 40 move as a unit. Other means may be used to connect these two elements.

Referring to Figure 1 , each long deck section 12 includes a hinge 50. Each hinge 50 defines spaced pivot bores which receive hinge pins 52, 54. These pivot points are linked to an associated pair of pivots 34a, 34b on an associated swing arm lug 30a by a pair of control links 58, 60. Grease fittings

62 provide a means by which the pivot and hinge pins can be lubricated. The pivot points on the hinge 50 together with the control links 58, 60 and the pivot points on the swing arm lug 30a define a four bar linkage and define a predetermined path of movement for the hinge 50 as the control links pivot about their associated swing arm lug 30a. Each short deck section 14 includes a hinge 66 defining two pivot bores, one of which is coincident with the pivot pin 52 held by the hinge 50 to which a long deck section is attached. In other words, the common pivot pin 52 pivotally connects both the control link 58 and the short deck hinge 66 to the hinge 50. As a result, the short deck section 14 pivots with the respect to the long deck section 12 about the pivot pin 52. The short deck hinge 66 also defines a inner pivot bore spaced radially inwardly with respect to its other pivot and is pivotally connected to an associated arm 26a defined by the spider 26 by a pivot pin 68.

In the preferred embodiment and shown best in Figures 1 and 4, edges 12a of each long deck section 12 are angled and define respective abutment surfaces for oppositely angled edges 14b of each short deck section 14. The angled edges 12a of the long deck sections 12 allows the short deck sections 14 to rotate inwardly during collapse of the drum without abrading the inside of a finished tire carcass TC (shown in Figure 4). In the illustrated configuration, angled edges 12a of each long deck section extend over the short deck section pivot 52.

In particular, an outer edge 14b' of each short deck section 14 is located to the left (as viewed in Figure 4) of a radial center line running from the center of the drum through the center of the pivot pin 52. As a result, as the short deck section 14 begins its inward rotation, the outer edge 14b' moves, virtually immediately, away from an inside surface of the tire carcass TC being supported by the drum. Absent this configuration, the edge 14b' would rub a portion of the inside surface of the tire carcass TC as it rotated to its collapsed position. As seen best in Figure 4, with the preferred edge configuration, the top outer surface of the log deck section 12 located at the upper most position (as viewed in Figure 4) provides support for the finished tire carcass TC when the drum is in the collapsed position shown in Figure 4. The angled configuration substantially inhibits the possibility of what is commonly called ply separation when a radial applied tire is being constructed on a more conventional tire drum.

Referring to Figures 1 and 4, the operation of the tire building drum will be explained. As indicated above, Figure 1 illustrates the "expanded" position of the tire drum 10. When material is being applied to the drum, the entire drum rotates as a unit, i.e. both the spider 26 and the swing arm 30 rotate in unison. In many if not most applications, inertia is used to produce the collapsing function. In particular, when collapse of the drum is desired, a brake or other suitable mechanism is applied to the quill 36 in order to stop rotation of the swing arm 30. It should be noted, that in Figures 1 and 3 the swing arm 30 is shown as being in a fixed position, i.e. it has not rotated. If the brake is applied as the overall drum is rotating, inertia in the drum will cause the spiders 26, 40 and attached deck sections 12, 14 to continue to rotate. In the illustrated embodiment, the spiders 26, 40 will rotate up to about 90 degrees relative to the swing arm 30 causing the control links 58, 60 to pivot with respect to the swing arm 30 to the positions shown in Figure 4. The angle of rotation may vary from about 40 degrees to about 86 degrees depending on drum size and the amount of collapse. As the spiders 26, 40 rotate with respect to the swing arm 30, the deck sections will rotate in the clockwise direction. The continued rotation of the deck section will cause the large deck sections 12 to move radially inwardly as the control links 58, 60 pivot with respect to the swing arm lug 30a that they are attached to. Figure 4 illustrates the pivoted position of the control links 58, 60. At the same time, the connection between the hinge 66 forming part of the short deck section 14 and the spiders 26,-40 will cause each short deck section 14 to pivot downwardly with respect to the long deck section to which it is attached (by the common hinge pin 52).

In the preferred embodiment, movement of the deck sections 12, 14 will continue until the short deck sections 14 contact an associated stop 76 which in the preferred embodiment includes a rubber bumper 76a. The bumper 76a is contacted by an abutment wall 78 forming part of each short deck section 14.

Expansion of the drum is accomplished by relatively rotating the spiders 26, 40 and swing arm 30 in the opposite direction so that the control links 58, 60 move from the pivoted position shown in Figure 4 to the radially extending position shown in Figure 1. At the same time, the spiders 26, 40 move counter clockwise with respect to the swing arm 30 in order to pivot the short deck sections in a clockwise direction about the hinge pin 52 to the position shown in Figure 1.

To provide additional stability when the drum is in the expanded position shown in Figures 1-3, a series of adjustable pads 90 are attached to the short deck sections 14 and include portions 90a that extend toward and lie beneath the edge 12b of an adjacent long deck section. The pads 90 provide radial support to the edges 12b of the adjacent long deck sections 12, when the drum is in the expanded position and help maintain circular alignment.

Several features of the disclosed drum improve its performances and serviceability as compared to prior art drums. For example, the hinges 50 for the long deck sections 12 are located outboard of the spiders 26, 40 and the swing arm hub 30 (Figure 2). This outboard location provides added support for the deck sections reducing the tendency for twisting in the overall assembly.

To facilitate servicing of the drum 10, the spiders 26, 40 include access holes 96, 98 (identified in Figure 4) which enable the removal of the pins holding the control links 58, 60 to the swing arm 30 without requiring disassembly of the drum 10. Once the pins are removed, the control links can be replaced again without requiring drum disassembly. Referring to Figures 2 and 3, poppets 100 (shown best in Figure 2) are provided which act as ball detents to releasably maintain the spider 26 and swing arm 30 in the expanded position. The poppets 100 require that a predetermined torque be applied between the swing arm 30 and spider 26 to produce relative rotation. This tends to inhibit premature collapse of the drum

10.

Figure 2 illustrates details of the poppet 100. The poppet 100 comprises a spring-loaded detent ball 104 which is carried in a tube-like element 106 attached to and forming part of the spider 26. A spring 107 urges the ball towards engagement with a detent recess or seat 108 forming part of the swing arm hub 30. When the detent ball 104 engages the detent seat 108, relative rotation between the spider 26 and swing arm hub is resisted. When sufficient differential forces are applied to the hub/spider, the detent ball 104 will be forced from its seat 108 and permit the spider to rotate relative to the hub, which will result in the tire drum to moving from the collapsed to the expanded position or visa versa.

To inhibit collapse of the drum during service, a drum lock 102 is provided which locks the drum in the expanded position by preventing relative rotation between the swing arm and spider. In Figure 2, the drum lock 102 is shown in the released or unlock position. The lock 102 comprises a pull out type dowel pin 112 carried by the spider 26 which is engagable with a recess 114 defined in the swing arm hub 30. The dowel pin 112 may be of conventional construction and, as is known, is commercially available from various sources. The dowel pin 112 is carried by a short radial arm 116, which is rotatable between a raised unlock position and a flush locked position. In particular, the radial arm is held to the spider by a suitable bolt 113. As seen best in Figure 2, a raised boss 117 is also carried by the spider. In order to secure the radial arm 116 and, hence, the dowel pin 112 to the raised boss 117, the dowel pin must be pulled outwardly (i.e., towards the left as viewed in Figure 2) so that the radial arm 116 can overlie the boss and enable the bolt 113 to be threaded through the radial arm into a threaded hole forming part of the boss 117.

When the arm 116 is rotated (approximately 90 degrees) to the locked position (see Figure 3), the radial arm is secured to the spider adjacent the boss 117 where a second threaded hole 119 is provided. In this position, the dowel pin 112 moves rightwardly from its position shown in Figure 2 and enters the locking recess 114. The radial arm is then secured to the spider by the bolt 113 which is threaded into the threaded hole 119. With the pin located in the recess 114, the spider 26 and the swing arm hub 30 are locked together and, as a result, movement of the tire drum from the expanded to the collapsed position is inhibited.

Although the invention has been described with a certain degree of particularity, it should be understood that those skilled in the art can make various changes to it without departing from the spirit or scope of the invention as hereinafter claimed.

Claims

I Claim:

1. A tire building drum, comprising: a) a plurality of drum segments which define a cylindrical drum surface when said segments are moved to a first position; b) a spider forming part of a rotatable hub, the hub being connectable to a drive source; c) a swing arm hub carried by said spider hub and relatively rotatable with respect to said spider hub; d) a second spider operatively coupled to said first spider so that the spiders rotate in unison; e) radial arms forming part of said spiders, interconnecting certain of said drum segments with said spiders; f) said swing arm including control links pivotally connected thereto and interconnected with said segments, such that relative rotation between said swing arm and said spiders moves said drum segments in coordinated movement from a collapsed position to an expanded position; and, g) mechanical stops engageable by said swing arm to resist relative rotation between said swing arm and said spider when said control links are in a vertical position or slightly over center.

2. The tire building drum of claim 1 , further including ball detents for providing a biasing force tending to maintain said drum segments in their expanded position.

3. The tire building drum of claim 2, further including access openings which enable the removal of mounting pins that hold said control links to said swing arm, without requiring substantial disassembly of the drum.

4. The apparatus of claim 1 , further including a lock mechanism which inhibits movement of said drum segments from their expanded positions to their collapsed positions.

5. A tire building drum, comprising: a) a plurality of drum segments which define a cylindrical drum surface when said segments are moved to a first position; b) a spider forming part of a rotatable hub, the hub being connectable to a drive source; c) a swing arm hub carried by said spider hub and relatively rotatable with respect to said spider hub; d) a second spider operatively coupled to said first spider so that the spiders rotate in unison; e) radial arms forming part of said spiders, interconnecting certain of said drum segments with said spiders; f) said swing arm including control links pivotally connected thereto and interconnected with said segments, such that relative rotation between said swing arm and said spiders moves said drum segments in coordinated movement from a collapsed position to an expanded position; and, g) a detent mechanism for providing a biasing force tending to maintain said drum segments in their expanded position.

6. A tire building drum, comprising: a) a plurality of drum segments which define a cylindrical drum surface when said segments are moved to a first position; b) a spider forming part of a rotatable hub, the hub being connectable to a drive source; c) a swing arm hub carried by said spider hub and relatively rotatable with respect to said spider hub; d) a second spider operatively coupled to said first spider so that the spiders rotate in unison; e) radial arms forming part of said spiders, interconnecting certain of said drum segments with said spiders; f) said swing arm including control links pivotally connected thereto and interconnected with said segments, such that relative rotation between said swing arm and said spiders moves said drum segments in coordinated movement from a collapsed position to an expanded position; and, g) structure defining access openings which enable the removal of mounting pins that hold said control links to said swing arm, without requiring substantial disassembly of the drum.

7. A tire building drum, comprising: a) a plurality of drum segments which define a cylindrical drum surface when said segments are moved to a first position; b) a spider forming part of a rotatable hub, the hub being connectable to a drive source; c) a swing arm hub carried by said spider hub and relatively rotatable with respect to said spider hub; d) a second spider operatively coupled to said first spider so that the spiders rotate in unison; e) radial arms forming part of said spiders, interconnecting certain of said drum segments with said spiders; f) said swing arm including control links pivotally connected thereto and interconnected with said segments, such that relative rotation between said swing arm and said spiders moves said drum segments in coordinated movement from a collapsed position to an expanded position; and, g) a locking mechanism which inhibits movement of said drum segments from their expanded positions to their collapsed positions.

8. The apparatus of claim 7, wherein said locking mechanism comprises a spring-loaded pin element engageable with an associated recess and further including a radial arm for moving said pin between unlocked and locked positions.

9. The apparatus of claim 5, wherein said mechanism comprises a spring-loaded ball detent engagable with a detent recess forming part of said swing arm hub.

10. The tire building drum of claim 1 , wherein said certain of said drum segments rotate about a pivot that interconnects said certain of said drum segments with said other drum segments.

11. The tire drum of claim 10, wherein said other of said drum segments move radially inwardly upon relative rotation between said swing arm and said spiders.