Patent Application
20130008611
Not Applicable
Not Applicable
1. Field of Invention
This invention pertains to apparatus useful in the manufacture of tires. More particularly, this invention pertains to a multi-piece sealing sleeve useful with a tire shaping drum to facilitate building and shaping of a tire carcass of the type used in the manufacture of radial automotive tires.
2. Description of the Related Art
Tires, such as for example radial automotive tires, of the type having an inner liner, a plurality of body plies, sidewalls, and a plurality of beads disposed proximate an inner circumference of the tire, are known in the art. It is understood generally that in traditional tire manufacture, following initial preparation of various components to be used, a generally cylindrical tire carcass is built through a process of assembling various components of a tire onto one or more tire building drums. Such tire carcasses normally include tire components such as multiple plies of tire bands, yarns, and one or more annular reinforcing tire beads at opposite ends of the tire bands. Thereafter, the tire carcass is expanded to a toroidal shape with the plies of tire bands forming an outer circumference of the toroid and the tire beads forming inner circumferences of the toroid. Often additional material is added to the tire carcass to form an uncured or “green” tire. The green tire is then formed into a desired finished geometry and cured to allow the tire to retain the finished geometry, thereby completing manufacture of the tire.
One apparatus and method useful in expanding a tire carcass to a toroidal shape is a tire shaping drum of the type discussed in U.S. Pat. No. 4,325,764, issued to Appleby et al. (hereinafter “the '764 patent”). In the '764 patent, a tire carcass is placed over a tire shaping drum having a pair of segmented, radially expandable annular support structures, each support structure defining a radially expandable bead seat for establishing a firm frictional connection between the support structure and a reinforcing bead of the tire carcass. The annular support structures defining the bead seats are typically adjustably repositionable proximate one another along an axial dimension of the tire shaping drum to assist both in mating the bead seats to the reinforcing beads of the tire carcass and in shaping the tire carcass to a toroidal shape. The tire shaping drum is adapted to allow injection of air or other fluid between the tire carcass and a portion of the tire shaping drum between the bead seats to allow the tire carcass to be expanded to a toroidal shape. An annular sealing sleeve of a resilient material, such as rubber, polymer, or the like, is provided along portions of the annular support structures between each radially expandable bead seat and an inner portion of the tire shaping drum to form a substantially airtight engagement between the tire carcass and the portion of the tire shaping drum interior of the bead seats.
Through repeated use of a tire shaping drum of the type having one or more annular sealing sleeves as described above, frictional contact between the reinforcing bead of the tire carcass and the annular sealing sleeve, as well as elastic deformation of the annular sealing sleeve through repeated expansion and contraction of the annular support structures, results in eventual wear and degradation of the resilient material forming the annular sealing sleeve. More specifically, it is noted that such wear and degradation often occurs most prominently along portions of the annular sealing sleeve proximate the bead seat portion of the annular support structure of the tire shaping drum. Such wear and degradation, if allowed to proceed indefinitely, eventually results in rupture, tearing, or surface deformation of the annular sealing sleeve, thereby resulting in loss of the ability of the annular sealing sleeve to maintain airtight engagement between the tire carcass and the portion of the tire shaping drum interior of the bead seats. Accordingly, it is often necessary to periodically replace the annular sealing sleeves on the tire shaping drum.
Replacement of an annular sealing sleeve on a tire shaping drum typically requires expansion of the replacement annular sealing sleeve radially outwardly to allow the replacement sleeve to fit over a corresponding annular support structure of the tire shaping drum. This expansion is typically accomplished through use of an annular frame having a plurality of inwardly facing hooks which are each extendable and retractable between a collapsed position and an expanded position. The hooks are adapted to be selectively extended inwardly of the annular frame to engage the replacement sleeve and selectively retracted toward the annular frame to stretch the replacement sleeve to an expanded geometry. The annular frame carrying the expanded annular sealing sleeve can then be positioned with respect to the tire shaping drum to surround the bead seat and inner portions of the annular support structure. Thereafter, the hooks of the annular frame can be selectively extended inwardly of the annular frame and disengaged from the annular sealing sleeve to allow the annular sealing sleeve to contract to fit along the bead seat and inner portions of the annular support structure.
The above-discussed process for replacement of an annular sealing sleeve on a tire shaping drum is often both cumbersome and time consuming, as it typically requires individual selective extension and retraction of the various hooks of the annular frame. Furthermore, operation of the above-discussed frame for stretching the replacement annular sealing sleeve can pose a safety risk in the event an annular sealing sleeve becomes disengaged from the frame while expanded on the frame. More specifically, if inadvertently released from the frame, the annular sealing sleeve may quickly contract to its unstretched configuration potentially striking and harming the user of the frame or other surroundings. Accordingly, a multi-piece sealing sleeve for a tire shaping drum which is configured to allow quick, safe, and convenient replacement of worn portions of the sleeve is desirable.
A multi-piece sealing sleeve for use with a tire shaping drum is disclosed herein. A typical tire shaping drum can include a support structure having a base portion and an annular, radially expandable and collapsible structure defining a bead seat. The bead seat can be radially expandable to engage a surrounding bead portion of a tire carcass. In one embodiment, the multi-piece sealing sleeve comprises an annular first layer of substantially air-impermeable material having an inner edge sized to surround the tire shaping drum base portion and an outer edge extending radially outwardly to overlie at least a portion of the radially expandable and collapsible structure of the tire shaping drum. An annular second layer of substantially air-impermeable material is provided and sized to overlie and establish sealing engagement with at least a portion of the annular first layer and the bead seat portion of the tire shaping drum. The first and second layers thus cooperate to establish a substantially airtight seal between the tire shaping drum base portion and the bead seat.
In several embodiments, a fastener is provided for securing at least one of the first and second layers along the radially expandable and collapsible structure of the tire shaping drum. In one embodiment, the fastener is defined by at least one annular band sized to circumferentially surround and exert compression along at least a portion of at least one of said first and second layers. In one application of the embodiment, the fastener is configured to fit within a fastening groove defined by the radially expandable and collapsible structure of the tire shaping drum.
The above-mentioned features of the invention will become more clearly understood from the following detailed description of the invention read together with the drawings in which:
A multi-piece sealing sleeve is disclosed herein and in the accompanying Figures. Referring to
Referring to
Referring now to
As shown in
As mentioned above, an outer section 44 of the first layer 12 is disposed in overlying relation along the sealing flange 36 such that the first layer 12 establishes a substantially airtight barrier between the inboard end 32 of the base portion 18 and the space between the sealing flange 36 and the base flange 30. A central portion 42 of the first layer 12 is capable of radial expansion and contraction in order to allow the first layer 12 to maintain an overlying relation over the base flange 30 and the sealing flange 36, thereby maintaining the airtight seal between the sealing flange 36 and the inboard end 32 of the base portion 18, as the bead seat 20 is expanded and contracted between the contracted position and the expanded position. Referring again to
The second layer 14 is defined by a generally tubular expandable and contractable sleeve of material which, like the first layer 12, is substantially impermeable to air. The second layer 14 is shaped and configured to overlie and conform closely to at least a portion of the outer section 44 of the first layer 12 to frictionally engage at least a portion of the first layer 12, and also to overlie at least a portion of the radially-extendable segments 26 forming the bead seat 20. In one embodiment, the second layer 14 is defined by a relatively smooth cylindrical tube formed of a resiliently elastic material, such as rubber, polymer, silicon rubber, or the like, and having a diameter slightly less than the diameter of the bead seat 20. In this embodiment, the second layer 14 is adapted to stretch slightly to conform along the surface of the outer section 44 of the first layer 12 and the radially-extendable segments 26 when the support structure 16 is in the collapsed position (see
Placement of the second layer 14 along the outer section 44 of the first layer 12 and at least a portion of the radially-extendable segments 26 forming the bead seat 20 allows the second layer 14 to establish and maintain a substantially airtight surface along the sealing flange 36 and the bead seat 20 as the support structure 16 is reconfigured between the collapsed position and the expanded position. Referring to
In certain embodiments, at least one fastener 24 is provided to secure at least one of the first and second layers 12, 14 in place along the support structure 16. For example, in the illustrated embodiment of
In application and use of the illustrated embodiment of the sleeve 10, it has been found that repeated expansion and contraction of the support structure 16 to engage and form a substantially airtight seal between a tire carcass bead 60 surrounding the bead seat 20 and the inboard end 32 of the base structure 18 typically results in wear of both the first and second layers 12, 14 due, at least in part, to repeated tensioning and compression of the material forming the first and second layers 12, 14. However, it has been found that such repeated use of the sleeve 10 results in more rapid wear of those portions of the sleeve 10 in contact with the tire carcass bead 60, namely, the second layer 14, at least in part due to the friction which occurs between the second layer 14 and the tire carcass bead 60 as the second layer 14 contacts and engages the tire carcass bead 60. The result is that, while both the first and second layers 12, 14 must be periodically replaced, the second layer 14 must be periodically replaced with a frequency approximating the frequency at which a prior art sleeve for a bead shaping drum must be replaced, while the first layer 12 must be replaced much less frequently. Thus, it will be understood that the sleeve 10 incorporating the first and second layers 12, 14 provides several unique advantages over the prior art.
For example, in several embodiments, the various regions and components of the first layer 12 are integrally formed such that the first layer 12 constitutes a unitary member, and likewise, the various regions of the second layer 14 are integrally formed such that the second layer 14 constitutes a unitary member. Referring again to
By contrast, it has been found that the second layer 14 must be periodically replaced with a frequency approximating the frequency at which various prior art sleeves for a bead shaping drum must be replaced. However, in several embodiments, the second layer 14 is configured to extend generally axially along the bead seat 20 defined by the radially-extendable segments 26 of the support structure 16. Thus, in several embodiments, the second layer 14 is more easily replaceable than the first layer 12. For example, in a typical method of fitting the second layer 14 of the sleeve 10 onto an existing tire shaping drum of the type illustrated, the second layer 14 is only slightly stretched to fit the second layer 14 around the outboard end 33 of the support structure 16 and onto the radially-extendable segments 26. In certain embodiments, the second layer 14 and the fastener 24 are each is sized, shaped, and composed of material suitable to allow the second layer 14 and the fastener 24 to be fitted around the outboard end 33 of the support structure 16 and onto the radially-extendable segments 26 using finger pressure alone. Accordingly, it will be understood by one of skill in the art that use of the sleeve 10 provides significant reduction in the time, hassle, and hazards associated with replacement of the multi-piece sealing sleeve on a tire shaping drum.
It will be understood that the specific dimensions of the various components of the sleeve may vary, depending at least in part on the need for frictional engagement of the first and second layers with one another and with the surfaces of the support structure 16. For example,
In certain embodiments, the lower edge 40 of the first layer is adapted to establish locking engagement with the support structure 16 along an interface between the base portion 18 and the base flange 30. For example, as shown in
It will be understood that, in certain embodiments in which portions of the layers 12, 14 are secured beneath a fastener 24 defining an elastic, generally toroidal member, excessive tensioning of the layers 12, 14 along planar dimensions thereof can, in some circumstances, result in rolling of the fastener 24 about a rotational axis of the torus, thereby allowing slippage of the portions of the layers 12, 14 along the support structure 16 and out from beneath the fastener 24. Such rolling of the fastener 24 can result, in some circumstances, in failure of the fastener 24 to maintain the layers 12, 14 in secure engagement along the fastener groove 50. Accordingly, in certain embodiments, the fastener 24″ defines a shape which is adapted to discourage rolling of the fastener 24″. For example, in the embodiment of
From the foregoing description, it will be recognized by those skilled in the art that an improved sealing sleeve for a tire shaping drum has been provided. While the present invention has been illustrated by description of several embodiments and while the illustrative embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant's general inventive concept.
