The invention relates generally to the field of spare tires, and more particularly to spare tires that can be used without removal of the damaged or flat tire from the vehicle. Description of Related Art

One of the most common, and often frustrating, maintenance procedures that a driver must perform is changing a flat tire. To change a flat, a driver must typically execute the following steps: 1) locate the jack in their trunk; 2) lift the vehicle with the jack; 3) remove the lug nuts securing the wheel; 4) remove the wheel carrying the flat tire from the vehicle; 5) remove the spare wheel and tire from the trunk; 6) position the spare wheel on the vehicle; 7) secure the spare wheel with the lug nuts; and 8) lower the vehicle to the ground. While the above procedure has been executed a countless number of times by unfortunate drivers, it is not without its drawbacks. Jacking up a vehicle can be a dangerous proposition for those not familiar with the proper safety precautions. Furthermore, manipulating the flat tire and wheel or spare tire and wheel requires a degree of strength and dexterity not possessed by all drivers.

Various attempts have been made to provide a substitute for the traditional spare tire. For example, U. S . Patent No. 4,546,807 to Cummins et al. discloses a modular spare tire comprised of a plurality of lightweight T-shaped segments. While the Cummins et al. spare tire uses pieces that are lightweight and easy to manipulate, the original flat tire must still be removed from the vehicle. U. S. Patent 4,708,400 discloses a spare tire that is torqued onto the outside of the disabled wheel through a through a complex hardware apparatus. U. S. Patent No. 4,929,032 discloses a two piece spare wheel that can be attached to a modified wheel via cap screws. To attached the second piece, a ramp is used to raise the disabled wheel . Other examples of spare tires for use without removing the flat tire include TJ. S. Patent No. 3,866,978 to Fine and TJ.

S. Patent No. 4,350,394 to Lehtinen. While these inventions may all be useful for their intended purposes, there remains a need for a spare tire that can be mounted on a vehicle without changing the flat that is lightweight and can be installed with a minimum of tools and effort.

Summary of the Invention One object of the present invention is to provide an add¬ on spare tire that can be installed without removing the wheel carrying the flat or disabled tire from the vehicle. Another object of the present invention is to provide a light weight spare tire that is easy to handle or manipulate. A further object of the present invention is that the spare tire can be installed with the only required tool being a hammer. Yet another object is that the spare tire take up less room in a trunk or storage space than a traditional full size spare tire.

According to the present invention, the foregoing and other ¹ objects and advantages are attained by a spare wheel comprising a first and second wheel half. The first wheel half includes an attachment plate portion. The attachment plate is attached to the wheel carrying the flat or disabled tire. Once attached, the first wheel half is rotated until the first wheel half supports the weight of the vehicle. Finally, the second wheel half is attached to the first wheel half.

Additional objects and advantages will become apparent from a consideration of the following description and drawings. Brief Description of the Drawings Figure 1 is a plan view of a flat tire carried on a wheel that is modified to accept the add-on spare tire.

Figure 2 is a plan view of a first wheel half with an attachment plate according to the invention.

Figure 3 is a cutaway view showing reception of the hanger pin in the wheel carrying the flat tire. Figure 4 illustrates seating of the pins extending from the attachment plate in the keyhole apertures of the wheel carrying the flat tire.

Figure 5 is a cutaway view showing reception of the pins extending from the attachment plate in the keyhole apertures of the wheel carrying the flat tire.

Figure 6 is a cutaway view showing the pins extending from the attachment plate having been received in the keyhole apertures of the wheel carrying the flat tire.

Figure 7 is a cutaway view illustrating insertion of a plate lock pin to secure the attachment plate to the wheel carrying the flat tire. Figure 8 illustrates rotation of the first wheel half with the attachment plate from a position of non-support to a position that it supports the weight of the vehicle.

Figure 9 shows the first wheel half with the attachment plate in a position that supports the weight of the vehicle. Figure 10 is another cutaway view showing the pins extending from the attachment plate having been received in the keyhole apertures of the wheel carrying the flat tire.

Figure 11 depicts the second wheel half being mounted to the first wheel half with the attachment plate. Figure 12 is an elevation view showing the mating plates of the first wheel half with the attachment plate.

Figure 13 is an elevation view showing the mating plates of the second wheel half.

Figure 14 shows the pins extending from the mating plates of the second wheel half.

Figure 15 shows the insertion of wheel lock pins to secure the second wheel half to the first wheel half with the attachment plate.

Figure 16 is a cutaway view taken along line A of Figure 15.

Figure 17 is a cutaway view taken along line B of Figure 15.

Figure 18 shows a side view of a trunk storage arrangement for the add-on spare tire according to the invention. Figure 19 shows a rear view of a trunk storage arrangement for the add-on spare tire according to the invention.

Figure 20 shows a wheel carrying a flat tire with long lug nut bolts.

Figure 21 shows a first wheel half with an attachment plate according to an alternative embodiment of the invention secured by the existing lug nuts.

Figure 22 shows a second wheel half secured to the first wheel half.

Figure 23 depicts a cutaway view of the alternative embodiment of the add-on spare tire. Detailed Description

With reference to the figures, an apparatus that achieves all the various objects of the present invention will now be described.

The add-on spare tire is made from two primary components: 1) a first wheel half 6a that mounts to wheel rim 20 carrying disabled or flat tire 1 (see Fig. 2) , and 2) a second wheel half 6b that mounts to first wheel half 6a (see Fig. 11) .

However, to use the spare tire, some minor modifications to wheel rim 20 are required. As shown in Fig. 1, wheel rim 20 contains a modified region 2 in which a plurality of apertures encircle lug nuts 3. These apertures include keyhole apertures

4 and plate lock apertures 5 used to attach wheel half 6a to wheel rim 20. The procedure for installing the spare wheel will now be described. The driver begins the installation process by removing wheel half 6a from the trunk or other storage compartment of the vehicle. Because wheel half 6a is approximately one-third the size of a full size spare, it is much easier to retrieve and manipulate. Preferably, the two wheel halves 6a and 6b are designed to provide a wheel and tire that is approximately the same circumference as the other wheels and tires on the vehicle; however, the width of the two wheel halves 6a and 6b is generally only one-half the width of the other wheels.

Thus, the spare wheel according to the instant invention provides the weight advantages of a "space saver" spare with the safety advantages of a full size spare. Ensuring that the add-on spare tire has the same circumference as the vehicle's

regular tire will prevent friction between the flat tire and the highway when driving to the repair shop. Wheel half 6a contains an attachment plate region defined by a plurality of keyhole slot pins 8 arranged in a circular pattern to match keyhole apertures 4 in wheel rim 20 (see Fig. 2) . As shown in Figures 2 and 3, the keyhole slot pin 8a in the top center of the attachment plate is used a hanger pin. Hanger pin 8a is matched to the keyhole aperture 4 located closest to the top of wheel rim 20 (i.e., the keyhole nearest the twelve o'clock position) . With hanger pin 8a inserted in a keyhole aperture 4 as depicted in Fig. 5, the driver then rotates wheel half 6a until the other keyhole slot pins 8 line up with keyhole apertures 4 (see Fig. 4) . Keyhole apertures 4 are configured with a large opening portion and a small opening portion shown best in Fig. 1. The driver will push keyhole slot pins 8 into the large opening portions of keyhole apertures 4 (see Figs. 6 and 10) . By twisting wheel half 6a in a clockwise motion, the driver forces slot pins 8 into the small opening portions of keyhole apertures 4 to attach wheel half 6a to wheel rim 20 (see Fig. 4) . A hammer can be used to firmly seat keyhole slot pins 8 into the small opening portions of keyhole apertures 4. Preferably, keyhole apertures 4 will have beveled edges to facilitate the shifting of keyhole slot pins 8 from the large opening portion to the small opening portion of keyhole apertures 4. While keyhole slot pins 8 can withstand strong pullout forces, they nevertheless could slip out of the small opening portions of keyhole apertures 4 back into the large opening portions of keyhole apertures 4. To prevent this, wheel half 6a contains reinforced apertures 9 (see Fig. 2) in its attachment plate region that correspond with plate lock pin apertures 5 in wheel rim 20 (see Fig. 1) . It is customary for plate lock pin apertures 5 to be interposed between keyhole apertures 4 to guarantee a mate plate lock pin aperture 5 for every reinforced aperture 9. Plate lock pins 9a are then driven through reinforced apertures 9 and plate lock pin apertures 5 with hammer 17 shown in Fig. 7. Plate lock pins 9a are designed to withstand strong shear

forces, but cannot resist strong pullout forces. However, the combination of plate lock pins 9a and keyhole slot pins 8 serve to secure wheel half 6a to wheel rim 20.

Once wheel half 6a is securely attached to wheel rim 20, the driver then uses the vehicle's own power to rotate wheel half 6a from a non-supporting position as shown in Fig. 8, to a position where it supports the weight of the vehicle as shown in Fig. 9. This maneuver requires some skill on the part of the driver since enough power must be supplied to force the vehicle upon wheel half 6a, but too much power will cause the vehicle to "fall off" wheel half 6a and once again rest on flat or disabled tire 1.

When the driver has succeeded in rotating wheel half 6a into a support position, wheel half 6b can then be attached. Figure 11 depicts wheel half 6b being joined to wheel half 6a. The two wheel halves are joined using a similar procedure as was used to attach wheel half 6a to wheel rim 20. Wheel half 6a has a pair of mating plates 10a and Ila that correspond to a pair of mating plates 10b and lib on wheel half 6b (see Fig. 11) . The mating plates could be welded on to the two halves or the plates could be stamped into the wheel halves when the halves are formed. Figure 12 provides a view looking down on mating plates 10a and Ila and shows keyhole apertures 12 and wheel lock pin apertures 14a. These apertures perform an analogous function to keyhole apertures 4 and plate lock pin apertures 5 in wheel rim 20. Figure 13 shows keyhole slot pins 13 and reinforced apertures 14 that are analogous to the identical parts on the attachment plate of wheel half 6a. As shown in Figs. 11 and 14, keyhole slot pins 13 are inserted into the large opening portions of keyhole apertures 12 and then shifted into the small opening portions of keyhole apertures 12. Hammer 17 can be used to firmly seat keyhole slot pins 13 into the small opening portions of keyhole apertures 12 as shown in Fig. 11. To secure the two wheel halves together, wheel lock pins 15 are driven through reinforced apertures 14 and wheel lock pin apertures 14a with hammer 17 as shown in Fig. 15. Figures 16 and 17 are cutaway

views of the two wheel halves joined together and taken along lines A and B respectively of Fig. 15. To facilitate transfer of load and lateral forces to wheel half 6a, bracket clip 16 is used to connect the body of wheel half 6b to the attachment plate of wheel half 6a as shown in Figs. 11, 15 and 16.

Figures 18 and 19 illustrate the space saving capabilities of the instant invention over traditional spare tires. Because the add-on spare tire and wheel comes in two halves, it can be stored in fender well area 18. Side by side, wheel halves 6a and 6b are no wider than a standard tire; however, wheel half 6a is just a little more than half as tall as a standard tire thus allowing the two halves to easily store in a fender well. By contrast, traditional spare 19 takes up significant space in the center of the trunk or in a compartment below the trunk area that otherwise could be used for additional trunk space.

Another useful feature of the instant invention is that tread 7 (Fig. 1 and Fig. 11) is merely rubber bonded to the peripheries of the wheel halves. This alleviates the especially distressing discovery that one's spare tire has lost its air pressure after completing the installation and lowering the vehicle to the ground.

Perhaps the most useful feature of the instant invention is that the spare can be installed with the use of only one tool--a hammer. Instead of fumbling with jacks, ratchets, sockets and wrenches, the spare can be installed in a manner of minutes with minimal effort. Moreover, the instant invention is only one-quarter the weight of a traditional spare thus requiring much less physical strength to perform the installation. Finally, Figs. 20 through 23 illustrate an alternative embodiment of the instant invention. Instead of modifying the existing wheel rim, longer lug bolts could be used to allow the wheel half with the attachment plate to be installed on the lug bolts as shown in Fig. 21. The second wheel half of the spare is attached in the same manner as discussed above (Fig. 22) . Figure 23 shows a cutaway view of the lug bolt embodiment taken along line A of Fig. 22. While the lug bolt embodiment

requires a wrench or ratchet and socket to remove the lug nuts, it allows existing vehicles to be retrofitted with longer lug bolts to make use of the add-on spare.

The above description is given in reference to an add-on spare tire that can be installed on a vehicle without removing the flat or disabled tire. However, it is understood that many variations are apparent to one of ordinary skill in the art from a reading of the above specification and such variations are within the spirit and scope of the invention as defined by the following appended claims: