Patent Application
20110117815
The description here relates generally to plastic gear boxes for toys and other small motorized devices, and particularly to simplified gear boxes.
There is a continuing and long-felt need for inexpensive, plastic gears for use in toys and similar products or applications. Gears transmit rotational movement and torque forces. Gears may be used to convert the high-speed, low torque output of a rotating electric motor to a low-speed, high torque output of a wheel drive shaft for a toy car. They also may be used to move the mechanical arms of, for example, a toy construction crane. Gears for toys should be safe, inexpensive, easy to assemble, and wear resistant. Plastic gears are suitable for toys because they are safe as they do not have sharp edges (as do metal gears), may be inexpensively formed by injection molding processes, and are tolerant of the dirt and wear encounter by toys, especially toy cars, trucks and construction vehicles.
As illustrated in
As illustrated in
One problem with this conventional system is the difficulty in assembling the components together when each component is molded or manufactured from different machines, as they often are. For example, one has to hold the very small end-supporting bushes 106, the hexagonal connecting elements 107 and the large output gear 108 in position before the metal hexagonal shaft 105 can pass through their cavity with precision and link the various components together. The longer the hexagonal shaft 105, the greater the difficulty is in inserting the shaft 105 through all of the components. Similarly, it is also difficult to insert the L-shaft 111 through the compound gear 109 on one end and to insert the axle of the L-shaft 111 at the other end onto the receiving element in the upper cover 110 of the gear box 100.
Another problem with conventional toy gear boxes is cost. Different components are conventionally made from different materials, and one may have to employ a dual material injection molding machine in the manufacture process. For example, the end-supporting bushes 106 are conventionally made of polyoxymethylene (“POM”), while the gear box compartment is conventionally made of acrylonitrile butadiene styrene (“ABS”). The hexagonal shaft 105 is conventionally made of metal, whereas the output gear 108 and the compound gear 109 are conventionally made of polyamide.
There is thus a need for a more cost effective gear box for use in toys and similar products or applications that is made from fewer materials, made with fewer parts, and is easier to assemble, yet which maintains the durability of conventional toy gear boxes.
The present embodiment provides a gear box for use in toy vehicles and similar products or applications. The gear box includes an upper cover having a grease groove and an integrated bush with a ridge, a motor engaged with the upper cover, a pinion gear engaged with the motor, a compound gear engaged with the pinion gear, an output gear with an integrated shaft engaged with the compound gear, the integrated shaft of the output gear having a center portion with a substantially circular cross section and end portions with substantially hexagonal cross sections, and a lower cover engaged with the upper cover, wherein the integrated shaft of the output gear extends through the integrated bush of the upper cover.
The output gear in the present embodiment can be made of plastic. The lower cover of the present embodiment can include plastic male locking portions and the upper cover can include plastic female locking portions that engage with the plastic male locking portions. In such gear boxes, the upper and lower covers can be engaged without the use of screws.
Grease groove and integrated bush with ridge 207 is provided in upper cover 201. Grease groove 207 allows for the application of a lubricant, such as silicone grease, in order to reduce the friction between the integrated shaft of composite output gear 205 and the portion of the integrated bush with ridge 207 with which it comes in contact. The ridge on the integrated bush 207 on upper cover 201 increases the contact area between upper cover 201 and output gear 205. This increased contact area decreases contact pressure on output gear 205 and therefore increases the lifespan of output gear 205. In addition, the application of a silicone grease on grease groove 207, which comes into contact with the integrated shaft of composite output gear 205, also reduces the frictional torque on composite output gear 205. Although the grease groove 207 is shown in the upper cover 201 of the present embodiment, it may equally be adapted in the lower cover 206 to extend the lubrication effect.
The new gear box 200 reduces the number of parts required to be assembled by more than 45% from the conventional gear box 100 illustrated in
Lower cover 206 includes plastic male locking portions 208 that are part of, and extend from the body of, lower cover 206. Similarly, upper cover 201 includes plastic female locking portions 209. As upper cover 201 and lower cover 206 are brought together to close the gear box assembly 200, male locking portions 208 are deflected by female locking portions 209, and then engage with female locking portions 209 such that upper cover 201 and lower cover 206 are fastened together by the engagement of male locking portions 208 and female locking portions 209. The gear box 200 is therefore able to be assembled more easily and securely than the conventional gear box 100 of
Because of the integrated pieces of the gear box 200, L-shaft 111 of the conventional gear box 100 is no longer required. In addition, because the integral shaft of output gear 205 is integrated with the output gear, end-supporting bushes 106 and middle-supporting bush 112 of the conventional gear box 100 illustrated in
Because of the reduction in the number of components and the size of the remaining components necessary for the proper functioning of the gear box 200, both upper cover 201 and lower cover 206 of the simplified gear box 200 can be made smaller than lower cover 102 and upper cover 110 of the conventional gear box 100 illustrated in
The reduction in the number and size of parts necessary for the proper functioning of the gear box 200 leads to significant advantages over the conventional gear box 100 illustrated in
Second, a reduction in the size of the overall gear box 200 reduces the materials used to make the gear box 200 as well as the overall weight of the vehicle into which the gear box 200 is placed. Third, because the gear box 200 requires significantly fewer parts than a conventional gear box 100, the gear box 200 requires fewer molds for the manufacturing process. Fourth, more component parts of the gear box 200 are integrated using more homogenous materials and less expensive materials than the conventional gear box 100. For example, the metal hexagonal shaft 105 of the conventional gear box 100 is significantly improved upon by making the shaft the same material as, and integrated with, output gear 205.
Fifth, the grease groove 207, with the integrated bush and ridge, allows for simplification of the assembly process along with a reduction in the number of components. At the same time, the lifespan of the output gear 205 is extended over that of output gear 108 of the conventional gear box 100. These advantages enhance production efficiency and lead to significantly lower assembly and molding costs, while also making the gear box 200 smaller, lighter, and longer lasting than a conventional gear box 100 as illustrated in
The four fitting positions 501 through 504 provide for adaptation to different wheelbases. Depending on the type of toy vehicle being assembled, which in turn has a bearing on the wheel distance, the clips 510 can be interlocked with the appropriate female interlocking portions. For example, a street version of a toy car might be selected with a different wheelbase than a racing version of a toy car. The multiple fitting positions illustrated in
The improved gear box described herein can be used in a wide range of toys that translate rotational movement and torque forces from a powered motor. For example and without limitation, the improved gear box can power a drive shaft that powers a toy car or truck, a propeller of a toy boat, plane or helicopter, the mechanical arm of a toy construction vehicle, and a broad range of light weight plastic and metal toys.
Although the invention has been described and illustrated in the foregoing illustrative embodiments, it is understood that the present disclosure has been made only by way of example, and that numerous changes in the details of implementation of the invention can be made without departing from the spirit and scope of the invention, which is limited only by the claims that follow. Features of the disclosed embodiments can be combined and rearranged in various ways within the scope and spirit of the invention.
