Background and Summary of the Invention In a wide array of applications, it is often desirable to create, trace, or copy curves or curved structures for use in creating, duplicating, and transferring the curve or for imparting a desired curve to an object. Examples of such applications include drafting, carpentry, boat hull design, landscaping, engineering, aeronautics, aerospace and prosthetics. It can be appreciated that there are numerous other applications for curve forming devices.

In mechanical drafting, curve formation has been done with the use of "flexible rules", which sometimes include two flexible strips of material that can be shaped into the desired curve and then locked together with a series of clamp screws, or the like. Examples of such flexible rules are disclosed in U. S.

Patents 407,756 and 447,657. These types of curve forming devices are generally effective; however, each individual fastening means must be separately and independently engaged and disengaged during use, this requires a significant amount of effort and time.

Other curve forming devices employ magnetic means and/or friction to attempt to maintain adjacent flexible members in a relative position to maintain a desired curve. Examples of these types of devices are disclosed in U. S.

Patents 3,134,176; 3,724,083; and 4,539,757. These designs require less time and effort to adjust and disengage as compared to the previously-mentioned types of devices. However, they are subject to slippage which causes misalignment and loss of the desired curve.

Therefore, what is desired is a curve forming device for creating, copying and imparting complex curves, which device is easily locked and disengaged to form and change curve shapes and which, once locked in place,

forms a rigid structure not susceptible to slippage.

The present invention provides a curve forming device which is applicable to an extremely wide variety of uses, and which overcomes the disadvantages of the prior designs.

The curve forming device of the present invention includes two flexible, elongated members which are joinable together by preferably releasable attachment means to form, or conform to, the shape of complex curves. One flexible member includes a plurality of projections rigidly affixed to and disposed along the length of the flexible member. Each projection extends outwardly perpendicular to the flexible member and includes an end face which is parallel to the flexible member. The attachment means preferably comprises hook-and- loop fasteners with one portion of the hook-and-loop fasteners affixed to the end face of each projection, and the complementary portion of the hook-and- loop fastener affixed to preferably the entire surface of the opposite flexible member. Thus, when the projections are urged against the opposite flexible member, the two flexible members Will be locked in place until the two flexible members are separated.

It can be appreciated that the formation of a curve using the present invention is extremely efficient. To form or copy a curve, one of the flexible members is simply formed into the desired (or existing) shape. Then the other flexible member is quickly and easily attached to the pre-formed member. At this point the curve forming device is locked in place until disengaged by forcibly separating the two flexible members, thereby separating the hook-and-loop fasteners.

Brief Description of the Drawings For a complete understanding of the above and other features of the invention, reference shall be made to the following detailed description of the preferred embodiments of the invention and to the accompanying drawings, wherein:

Fig. 1 is a side elevational view of a first embodiment of the curve transfer device of the invention; Figs. 2 and 3 are side elevational views of the curve transfer device of Fig. 1; Figs. 4 and 5 are front elevational views of one portion of the first and a second embodiment of the invention, respectively; Fig. 6 is a side elevational view of the curve transfer device; Figs. 7 and 8 are perspective views of third and fourth embodiments of the invention, used as a splinting apparatus.

Detailed Description of the Invention Referring to Figs. 1-4, the curve forming device 10 of the present invention includes two elongated flexible members 12,14 preferably formed from flexible plastic sheeting. Each flexible elongated member has an opposing surface 13,15, the opposing surface 15 of the second elongated flexible member 14 forms a continuous contact surface 17.

Fixedly attached to the opposing surface 13 of one flexible member 12 are a series of rigid projections 16, which are preferably of uniform shape and length and are preferably uniformly spaced at regular intervals along sub- stantially the entire length of the flexible member 12. The projections 16 extend outwardly perpendicular from the opposing surface 13 of the flexible member 12 and include an end face 18 which is substantially parallel to flexible member 12. The projections can be connected to the flexible member 12 with any suitable fastener, such as screws or rivets, or the like. Alternatively, the projections 16 can be integrally formed with the flexible member 12, such as by injection molding or thermal forming. Affixed to the end face 18 of each pro- jection 16 is a preferably releasably engageable attachment means 20. Affixed to an opposing surface 22 of the opposing flexible member 14 is a preferably complimentary attachment means 24 which cooperates with the releasable attachment means 20 affixed to the projections 16. The releasable attachment

means 24 affixed to the opposing flexible member 14 is disposed substantially continuously along preferably the entire length of the contact surface 17, such that the complementary attachment means affixed to the projections 16 will securely mount at any location along the length of the contact surface 17.

The attachment means 20 is operable to substantially prevent relative motion of the two elongated flexible members at least along their respective longitudinal axes such that the shaped curve forming device will maintain its configuration.

Hook-and-loop fasteners, and the like, are suitable releasable attachment means for the curve forming device 10 of the present invention. Preferably, one portion of the hook-and-loop fastener is rigidly affixed over the entire surface area of the end face 18 of each projection 16. A complementary portion of the hook-and-loop fastener is rigidly affixed over substantially the entire surface area and/or length of the contact surface 17 of the opposing flexible member 14.

It can be appreciated though that other types of attachment means are equally suitable. For example, one or both of the opposing flexible member 14 or projections 16 could include a pressure-sensitive adhesive thereon to provide a permanent or semi-permanent connection between the flexible members 12, 14. The attachment means should, however, engage upon contact.

As best shown in Fig. 2, to form (or copy) a curve, the flexible members 12,14 are first partially or completely separated. Then, one flexible member (here, the flexible member 12 having the projections 16) is formed into the desired shape. Finally, the opposing flexible member 14 is connected to the pre-formed flexible member 12 with the projections 16 in contact with the contact surface 17 to secure the curve forming device 10 in the desired shape, as depicted in Fig. 3.

In attaching the opposing flexible member 14, it is preferable to begin at one end of the pre-formed flexible member 14, (e. g., the lower end as depicted in Fig. 3), sequentially connecting the two flexible members 12,14 at

successive projections 16. This ensures that each projection 16 will attach to the opposing flexible member 14 to provide a strong, rigid connection therebetween, such that the curve forming device 10 will maintain the desired shape even if it is subjected to a load.

To separate (and possibly reshape) the curve forming device 10, end portions 26,28 of the flexible members 12,14 are grasped and urged apart to detach the connection (if possible) between the projections 16 and the opposing attachment means. The remaining attachments are disengaged in sequence in a similar manner.

The projections 16 add rigidity to the curve device 10 by creating a distance between the two flexible members 12,14 and thus between the two flexible members 12,14 and a neutral axis of flexure of the assembled curve forming device 10. Thus, the spaced-apart flexible members 12,14 act much like the opposed spaced-apart flanges of an I-beam which are interconnected by a spacing flange, to stiffen and strengthen the structure.

Preferably, the projections are substantially uniform in shape and length and have a height about 1.3 times a width thereof. The projections can be any suitable shape, such as cylindrical, rectangular, or square.

Referring to Figs. 4 and 5, the projections 16 and 16'can be arranged in any desired configuration including a single column or a two-dimensional array. In addition, the curve forming device can be constructed in many sizes and gauges.

Referring again to Fig. 2, in one embodiment, the flexible members 12, 14 can be formed from 0.044 inch thick, 1.048 inch wide, plastic sheeting 3 feet in length and the projections can be cylinders each having a 0.625 inch diameter and a 0.780 inch height. The dimensions of the flexible members and the projections, and the strength of the hook-and-loop fasteners can be reduced or enlarged separately or concurrently depending on the length of the curve to be formed and the possible forces to which the device will be subject.

Referring to Figs. 7 and 8, one of the many uses of the curve forming device 10 of the present invention includes modelling and shaping parts of the human body for such applications as prosthetic manufacturing or joint/limb immobilization, among others. In modelling human body parts, the curve forming device 10, while in a disengaged state, can be conformed to the shape of the body part. Then the opposing piece of the curve forming device 10 can be connected to lock the pre-formed portion in place and lock the curve. Joint and limb immobilization can be accomplished similarly by then affixing (such as with an adhesive wrap) the curve forming device to the associated body part.

The curve forming device 10 can also be used in a wide variety of other applications including boat hull design, drafting, carpentry, landscaping, aerospace engineering, display and backdrop construction, and many others.

Referring to Fig. 9, a particularly advantageous use of the curve forming device 10 of the present invention is for copying dynamic or changeable curves, or curves in constrained spaces. For this type of application, a removable separator 30 is used to prevent the releasable attachment means 20,24, from connecting until the desired shape or the changing curve is attained, or until the curve forming device 10 is inserted into the constrained space. At the proper time, the separator 30 withdrawn from between the projections 16 and the opposing flexible member 14, thereby allowing the releasable attachment means to connect to form the desired curve.

Preferably the separator 30 is formed in the shape of a channel with a bottom 32 and two side portions 34,36. The separator 30 is inserted over the projections with the bottom 32 resting on the end face 18 and releasable attach- ment means 20 of the projections 16. The opposing flexible member 14 is secured over the separator 30 and to the other flexible member via temporary fastening means such as a rubber band 40, or the like. The temporary fastening means 40 insures that the opposing flexible member 14 remains aligned with the projections 16, for eventual attachment thereto. The side walls 34,36 of the

separator 30 insure that the separator remains aligned over the projections 16 both when the curve is being formed and when the separator 30 is being withdrawn.

The curve forming device 10 provides an efficient and inexpensive means to create, copy and transfer curves to and between structures. The curve forming device can be used to semi-permanently or permanently assume the shape of an existing or desired complex curve by simply shaping one of the elongated flexible members as desired and then attaching the other flexible member to the pre-shaped member. Once connected, the two flexible members will retain the entire and exact curve thereby allowing the curve to be trans- ferred analyzed or imparted on another structure. The device is easily reshaped by disengaging the releasable attachment means. As can be appreciated, the uses of the device are only limited by the imagination.

It should be understood, of course, that the specific form of the invention herein illustrated and described is intended to be representative only, as certain changes may be made therein without departing from the clear teachings of the disclosure. Accordingly, reference should be made to the following appended claims in determining the full scope of the invention.