Patent Application
20150158101
The present invention relates to the threading holes with a tap. More specifically, the present relates to a thread tap adapter for interfacing conventional thread taps with a driving mechanism.
In the metalworking and fabrication fields, there is an ongoing need to create threads in a hole for rotatably interfacing with corresponding threads of screws, bolts and other rotatably engaged fixation elements. Thread taps comprise a bit portion that is rotatably inserted into a bore hole to cut threads into the walls of the bore hole. As materials secured by screw threads are often hardened materials, the amount of rotational force required to cut the screw treads can be substantial. Accordingly, the existing integrated devices for driving a thread tip into a hole are often large and cumbersome. Some devices for driving a tap, such as T-handle wrenches with a collet-type engagement comprise handle portions as long as the tap itself to provide sufficient leverage in rotating the thread tap. The large size, long rotational arc or simply the cumbersome shape of the driving device can prevent or significantly hamper the use of the tread tap.
Driving devices such as drills, presses, wrenches and other motor or hand driven driving devices are often secured to the thread taps without integrated driving devices. These thread taps typically comprise an engagement portion having a square profile. However, the three-jaw chucks commonly found on hand drills or drill presses are often incompatible with or poorly secure the square profile of the engagement portion. Specifically, the three jaws cannot securely grip the four flat surfaces of the engagement portion of the tap. Similarly, the six point sockets or box wrenches that are often used to manually rotate the thread tap can be incompatible with the square profile of the thread tap. Accordingly, a tap adapter is often employed to provide an interfacing element between the driving device and the thread tap.
U.S. Pat. No. 5,213,347 to Rulon et al. discloses a tap adapter for use with a ratchet that comprises a similar structure to a standard socket and is engagable to a ratchet in the same manner as a conventional socket. However, Rulon does not address the incompatibility between a thread tap with a three-jaw chuck. The outer profile of the Rulon tap adapter is cylindrical and cannot be effectively gripped by a three jaw chuck. Additionally, in situations where little clearance is available proximate the end of the thread tap, the Rulon tap adapter may not be suitable as requiring additional clearance for fitting and engaging the ratchet.
U.S. Pat. No. 5,037,251 to Roth discloses a thread tap comprising a shank having both a traditional square end profile and a hexagonal profile. However, as the multi-profile shank is integrated into the thread tap itself, each conventional tap would necessarily be replaced at great expense. In addition, a hexagonal shank profile alone creates a substantially more complicated and expensive manufacturing process than standard taps. The manufacturing process is further complicated and made more expensive as manufacturing entails both a traditional square shank profile and a hexagonal shank profile. As thread taps are necessary hardened to effectively cut the threads in the bore holes, the thread taps can become brittle and susceptible to damage when dropped. The expensive manufacturing process substantially increases the cost of replacing a damaged or broken thread tap.
Accordingly, there remains a need for applying rotational energy to a thread tap for a non-integrated drive device.
The present invention is generally directed to a thread tap adapter for interfacing the engagement features of a driving device with a thread tap for driving rotation of the thread tap with the driving device. Specifically, the thread tap adapter can comprise a central axial bore for receiving the tread tap. The thread tap adapter can also comprise an engagement element positioned within the central axial bore for radially engaging the shank portion of the thread tap to retain the thread tap within the central axial bore. The engagement element can comprise a flexible material deformable to positively engage the shank portion of the thread tap or a rigid element that forms a friction fit with the shank portion of the thread portion. The engagement element provides a tool-less retention element that secures the thread tap within the central axial bore without the aid of a set screw or other element that must be tightened after the thread tap is inserted. In certain embodiments, the retention element provides a secondary support preventing wobble of the thread tap within the axial bore. Similarly, the retention element can operate as a second engagement point by which rotation of the thread tap adapter is translated to the thread tap.
In certain embodiments, a thread tap adapter can further comprise a flange extending from the thread tap adapter body along a plane generally perpendicular to the central rotational axis of the thread tap adapter. The flange defines an alignment surface for preventing axial movement of the engagement features of the driving device along the adapter body thereby reducing the likelihood that the engagement features will inadvertently separate or slip from the thread tap adapter during driving of the thread tap. The flange can also serve as a stop limiting the axial depth of the three-jaw chuck and engagement features that are inserted over the thread tap adapter axially. In certain embodiments, the thread tap adapter can comprise parallel flanges defining opposing alignment faces for further limiting axial movement of the engagement features to between the parallel flanges.
A thread tap adapter, according to an embodiment of the present invention, can comprise an adapter body defining a central axial bore having a drive portion and a shank portion. The drive portion can comprise a square profile or other profile engagable to the corresponding drive portion of thread tap, wherein the driver portion of thread tap adapter prevents rotation of the thread tap adapter relative to the thread tap. Similarly, the shank portion comprises a cylindrical profile or other profile positioned engagable to, but permits rotation of the thread tap adapter around the thread tap. The thread tap adapter further comprises a retention element positioned within the shank portion of the thread tap adapter, wherein the retention element is adapted to engage the shank portion of the thread tap. In certain embodiments, the thread tap adapter can further comprise at least one flange extending radially outward from the thread tap adapter, wherein each flange comprises an alignment surface for guiding the engagement of the driving device to the thread tap adapter.
The above summary of the various representative embodiments of the invention is not intended to describe each illustrated embodiment or every implementation of the invention. Rather, the embodiments are chosen and described so that others skilled in the art can appreciate and understand the principles and practices of the invention. The figures in the detailed description that follow more particularly exemplify these embodiments.
The invention can be more completely understood and appreciated by referring to the following more detailed description of the presently preferred exemplary embodiments of the invention in conjunction with the accompanying drawings, of which:
While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
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Similarly, the retention element 46 engages the shank portion 58 of the thread tap 52, wherein the retention element 46 is sized such that the insertion of the thread tap 52 into the central axial bore 28 deforms or otherwise engages the retention element 46 to provide positive engagement or frictional engagement of the shank portion 58 of the thread tap 52. The retention element 46 prevents the thread tap 52 from inadvertently moving axially within the central axial bore 28. In certain embodiments, the inner edge of the retention element 46 is contoured or faceted to correspond to the exterior shank surface 64. In certain embodiments, in which the inner shank surface 44 of the thread tap adapter 20 does not the engage the exterior shank surface 64 of the thread tap 52 the retention element 46 provides a second engagement point between the thread tap 52 and the thread tap adapter 20. The dual engagement points prevent the thread tap adapter 20 from rotating relative to the thread tap 52.
In use, a driving device such as, for example, a box wrench, an open ended wrench, a crescent wrench, socket wrench or motorized drill is operably engaged to the external surface 30 of the adapter body 22, wherein the individual sides 31 allow for capture and engagement of the adapter body 22 by the engagement features of the driving device. The first flange portion 32 is positioned such that the alignment face 34 limits the downward axial travel of the engagement features of the driving device so as to prevent unintentional disengagement of the driving device and the adapter body 22 in the case of the driving device comprising a box, open ended or crescent wrench during operation of the driving device to rotate the adapter body 22. In this manner, the driving device is prevented from slipping down and off the adapter body 22 during application of torque with the driving device. In certain embodiments in which the thread adapter 20 is engaged by sliding the engagement features onto the thread adapter 20 along an axis parallel to the central rotational axis of the thread adapter 20, the first flange portion 32 operates as a stop preventing further axial movement of the driving device when the engagement features are properly aligned with the adapter body 22. In certain embodiments, the second flange portion 36 and opposing alignment face 38 cooperate with the first flange portion 32 to prevent axial movement of the driving device, both downward and upward, during rotation of the thread tap 52 via the thread adapter 20.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it will be apparent to those of ordinary skill in the art that the invention is not to be limited to the disclosed embodiment, that many modifications and equivalent arrangements may be made thereof within the scope of the invention, which scope is to be accorded the broadest interpretation of the appended claims so as to encompass all equivalent structures and products.
