Wheelwright machines – Rubber tire mounting and/or demounting apparatus – For collapsing or shifting tire axially
Reexamination Certificate
1998-06-15
2001-02-06
Scherbel, David A. (Department: 3723)
Wheelwright machines
Rubber tire mounting and/or demounting apparatus
For collapsing or shifting tire axially
C157S001200, C157S001170
Reexamination Certificate
active
06182736
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to the realm of tire changing, where many machines, devices and accessories are designed to assist in making the process of changing a tire less physical and more efficient.
It will be appreciated by those skilled in the art of designing and manufacturing equipment used to change the tubeless tires mounted on the rims of cars, light trucks and other vehicles, that such equipment must perform quickly and efficiently in order to be competitive in the marketplace. Modest improvements in the industry can thus become significant.
The type of equipment for which Applicant's invention is designed is the swing-arm rim-holding tire changer. Examples of such equipment include the tire changers manufactured by Hennessy Industries, Inc., Applicant's Assignee and marketed under the trademarks COATS™ and AMMCO™, including the COATS™ Model 5030A, Model 5060A-E and Model 5060AX-EX. However, there are many manufacturers of such equipment, including FMC Corporation of Chicago, Ill.; Corghi of Correggio, Italy, and SICE of Correggio, Italy. Equipment of this type has been readily available and on the market for many years, is the subject matter of numerous patents and has been described in a variety of publications, bulletins and brochures, operating instructional manuals, and the like. One such machine is illustrated in the design patent issued to Applicant as co-inventor in U.S. Design Pat. No. 293,916.
In the normal tire-changing procedure, the operator places a rim on the table of the rim-holding tire changer, secures the rim to the table, places a tire over the rim, mounts the tire on the rim by using the mount/dismount head to force the bead over the rim, and then fills the air chamber of the tire with air to inflate the tire. In most cases, a tire must first be removed from a rim before installing a new tire. This procedure is described in detail in U.S. patent application Ser. No. 08/516,129, the substance of which is incorporated here and by reference, and which is assigned to the Assignee of the present invention.
The design of wheel and tire configurations constantly changes for many reasons, including improved durability and performance. The equipment used for changing tires must change accordingly in order to accommodate these new designs. The present invention is directed to a device used to assist in the changing of a tire.
Recent innovations in tire design have resulted in wider, lower profile tires with stiffer sidewalls. One such tire is referred to as a “run-flat” tire, which is designed to run for a specified period of time after having been punctured. The characteristics of these tires that make them more durable also make them much more difficult to change due to their increased width and decreased flexibility. Further, changing these tires is a more dangerous operation because the operator must apply a greater force to disengage the tire bead from the rim. These and other considerations must be incorporated into the development and design of more effective, efficient and safe tire changers.
To meet this challenge most manufacturers of tire changers have added powered features to their equipment to assist the operator in dealing with the increasing difficulty of changing a tire. These features include powered arms with attached pivoting devices for pushing against the tire to offset the manual effort required by the operator. Currently, all assist devices on competitor's equipment are designed such that the entire arm mechanism must be moved vertically in order to properly position attachments such as blocks and rollers against the tire surface to perform their specified function. Positioning the entire mechanism can be a cumbersome and time consuming process, particularly when the several tires must be changed.
Most of these arm mechanisms consist of a sliding contact block attached to a jointed arm that moves up and down on a vertical guide that is attached to the chassis of the tire changer. The arm is usually powered by an air cylinder. The contact blocks of devices that are currently available aid only in the separation of an upper tire bead from a tire rim. They do not provide any means for assistance in positioning the demount head. Further, they do not aid in lower bead separation. Finally, tires sometimes explode during the inflation step, and the off-centered support offered by these devices does not provide the most effective explosion restraint.
What is needed is a mechanism having a contact block that can be easily positioned over the tire and then raised and lowered to assist in mounting and demounting activities and that provides superior restraint during inflation of the tire.
SUMMARY OF THE INVENTION
The present invention comprises a multi-function helper arm mechanism for use in conjunction with a rim-holding tire changer. The helper arm may either be attached to the existing structure of a tire changer or it may be mounted on a stand-alone unit. The device offers several advantages over other existing designs. For example, the entire arm assembly of other devices moves up and down along a vertical guide which, therefore, requires that the total weight of the arm be moved up or down every time the arm is repositioned. This typically requires a reinforced structure with a power capacity to move the total weight of the mechanism.
The device of the present invention, on the other hand, includes a contact block attached to an adjustable vertical member, such as a cylinder assembly, that is, in turn, mounted on the forward end of a jointed arm. The rear end of the arm is pivotally mounted to the existing structure of the tire changer, typically the tower portion. However, the arm may alternatively be mounted to the tire changer at any convenient and operable location, or it may be mounted to a stand-alone support device.
The vertical member preferably includes a cylinder mechanism with a cylinder shaft and corresponding control means for raising and lowering the cylinder shaft to the desired vertical position. A handle may be provided to assist the operator in properly positioning the helper arm with respect to the tire.
The contact block or foot includes a shoulder having a rim-stop surface that rests on the rim flange and a downwardly projecting heel that may be depressed against the tire bead. The contact block further includes a ramped surface for engaging and forcing the tire sidewall into the drop center of the wheel and a hook for supporting the tire during demounting of the lower bead.
The helper arm of the present invention may be used to accomplish at least four major functions: (1) assisting in mounting and demounting activities by forcing the upper bead of the tire into drop center; (2) assisting the operator during demounting of the lower bead by raising or pulling the tire upward, thereby allowing the lower bead to move into the wheel's drop center; (3) providing explosion restraint when the contact block is positioned against the center of a wheel; and (4) assisting in the positioning of the mount/demount head.
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Carpenter David M.
Cunningham Charles L.
Hennessy Industries, Inc.
Ojini Anthony
Scherbel David A.
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