Abstract:
In order to facilitate the removal of a fastener of the type having a head on a shank, a tool for removing such a fastener is disclosed. The tool includes support for a collet which makes it possible to impart torque for removal of the fastener through rotational movement of the collet in relation to the head of the fastener. Further, the collet is adjustably positioned on the support and is dimensionaly adjustable for gripping the head of the fastener.

Description:
FIELD OF THE INVENTION 
     The present invention is generally related to fastener removing tools and, more particularly, a tool for removing a one-way fastener of the security fastener type. 
     BACKGROUND OF THE INVENTION 
     Security fasteners which are tamper-resistant or vandal-resistant are now well known. These fasteners typically have tamper-proof screw heads wherein the screw heads are adapted to be driven in a clockwise direction utilizing a conventional screw driving blade, and they are typically adapted to remain in a fully-installed condition without being able to be removed by further use of a conventional screwdriver blade when operated in a counterclockwise direction. However, security fasteners must occasionally be removed by authorized personnel. 
     In connection with a typical screw of the security type, it has a generally circular head with both flat and convex upper surface portions. While such a security fastener can be installed with a conventional screwdriver, there is a need for a special tool for removal thereof. 
     Over the years, there have been a variety of different proposals for tools to accomplish this particular objective. Among the various proposals are the tools which are disclosed in Gullborg U.S. Pat. No. 2,103,944; Cerny U.S. Pat. No. 4,800,787; and LaSante, Sr. U.S. Pat. No. 4,429,599. Unfortunately, each of these tools requires a specially-designed fastener which renders them less than desirable for any existing fastener applications. 
     More specifically, there would be a natural reluctance to utilize any of the tools which have been suggested in these earlier patents. They would not only be unsuitable for removing existing types of security fasteners but, equally important, they would require a substantial capital investment inasmuch as specially-designed screws would need to be manufactured and marketed. Clearly, the Gullborg &#39;944 patent, the Cerny &#39;787 patent, and the LaSante, Sr. &#39;599 patent have failed to meet the need for a unique security fastener removal tool. 
     More recently, there was a significant advancement in security fastener removal tools which is disclosed and claimed in Kozak U.S. Pat. No. 5,450,776. There has remained, however, the need for still additional flexibility and, in particular, the capacity for both radial and axial adjustability of the tool components. Still additionally, there has remained the need for a fastener removing tool of a type which is well suited for removing any form of head-on-a-shank fastener. 
     The present invention is directed to overcoming one or more of the foregoing problems and achieving one or more of the resulting objects. 
     SUMMARY OF THE INVENTION 
     It is, therefore, a principal object of the present invention to provide a unique improved removal tool for use in removing a fastener of the type having a head on a shank. It is also an object of the present invention to provide a tool for removing the most commonly utilized security fasteners and, specifically, one-way fasteners of the type generally in widespread use to accommodate ease of removal of existing installed fasteners of this particular type. It is an additional object of the present invention to provide a tool for removing a fastener having a pair of both flat and convex head surface portions thereon. 
     Accordingly, the present invention is directed to a tool for removing a fastener of the type having a head on a shank wherein the tool includes means for supporting a collet. The collet supporting means supports the collet so as to be able to impart torque through rotational movement of the collet in relation to the head of the fastener. Further, the tool includes means for adjustably positioning the collet on the collet supporting means and the collet includes means for adjustably gripping the head of the fastener. 
     In the exemplary embodiment, the collet supporting means preferably includes an elongated shank and the collet positioning means includes a first portion of the collet. The elongated shank advantageously has an end to be placed in engagement with the head of the fastener which includes a pair of fastener engaging tips. Also in the exemplary embodiment, the fastener gripping means preferably includes a second portion of the collet axially spaced from the first collet portion so as to be near the head engagement end of the shank. 
     As for other details of the exemplary embodiment, the second collet portion suitably includes a plurality of teeth about an inner surface for biting into the head of the fastener. With this arrangement, the first collet portion preferably has a tightening collar with right hand threads and the second collet portion preferably has a tightening collar with left hand threads. 
     In a highly preferred embodiment, a tool for removing a one-way fastener of the type having a generally circular head with a flat upper surface portion and a convex upper surface portion is provided. The tool again advantageously includes an elongated shank having an end with a pair of fastener-engaging tips extending therefrom for engagement with the head of the one-way fastener. Still additionally, the tool again preferably includes a collet which is disposed on the shank such that rotational movement of the shank serves as to cause rotational movement to be imparted to the collet. 
     Still further, the tool preferably includes means for adjustably positioning the collet relative to the fastener-engaging tips to cause the collet and the fastener-engaging tips both to engage the head of the one-way fastener whereby rotational movement of the shank imparts torque to the head of the one-way fastener through rotational movement of the fastener engaging tips as well as rotational movement of the collet. 
     Still additional details of the present invention include the collet having means for adjustably gripping the head of the one-way fastener while the fastener-engaging tips are also in engagement with the head of the one-way fastener. The collet positioning means preferably includes a first collet portion and the fastener gripping means preferably includes a second collet portion axially spaced along the collet from the first collet portion. The first collet portion advantageously comprises a tightening collar threaded onto the collet with right hand threads and the second collet portion likewise advantageously comprises a tightening collar threaded onto the collet with left hand threads. The fastener gripping means preferably includes a plurality of teeth which are disposed about an inner surface of the collet for the purpose of biting into the head of the one-way fastener for imparting torque thereto. In a highly preferred embodiment, the teeth are each angled for counterclockwise biting engagement of the head of the one-way fastener about a radial line passing through an axis of rotational movement of the collet. 
     As will be appreciated, the teeth could, alternatively, extend radially, or they could be angled for clockwise rotation for removing a fastener having left-hand threads. 
     In yet another respect, the present invention is particularly well suited as a tool for removing a one-way fastener of the type having a threaded shank with right hand threads. The tool may further advantageously be formed as a double collet adapted to be adjustably secured to an elongated shank such that counterclockwise rotational movement of the shank causes counterclockwise rotational movement to be imparted to the double collet. With this arrangement, the double collet includes a first collet for adjustably positioning the fastener-engaging tips in relation to a second collet so that they both engage the head of the one-way fastener. 
     As for the second collet, it advantageously comprises means for adjustably gripping the head of the one-way fastener together with the fastener-engaging tips after the fastener-engaging tips have been adjustably positioned relative to the second collet using the first collet whereby counterclockwise rotational movement of the shank thereafter serves to impart torque to the head of the one-way fastener through the resulting counterclockwise rotational movement of the fastener-engaging tips as well as the resulting counterclockwise rotational movement of the second collet. 
     In a most highly preferred embodiment, the shank has an end of non-circular cross-section opposite the fastener-engaging tips to be manually or power driven to impart torque to the head for removing the one-way fastener. The double collet also preferably has a knurled intermediate segment between the first collet and the second collet and the collars of the first collet and the second collet are also preferably knurled. Furthermore, the fastener-engaging tips each advantageously have an angled surface to bite into the head of the one-way fastener whenever torque is imparted through counterclockwise rotational movement of the tool. 
    
    
     Other objects, advantages and features of the present invention will become apparent from a consideration of the following specification taken in conjunction with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a view partially in section of a fastener removing tool in accordance with the present invention; 
     FIG. 2 is an end elevational view of the fastener removing tool illustrated in FIG. 1; 
     FIG. 3 is an exploded perspective view of the fastener removing tool illustrated in FIG. 1; and 
     FIG. 4 is a top plan view of a one-way fastener of the general type which is to be removed with the tool of FIG. 1. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the illustrations given, and with reference first to FIG. 1, the reference numeral 10 designates generally a tool for removing a fastener of the type having a head 12 on a threaded shank 14. The fastener may be of any type having a head and shank, although one particular application for the tool 10 is for removing a one-way fastener such as that illustrated and designated 16 in which the head 12 is circular and has a pair of flat upper surface portions 18a and 18b together with a pair of convex upper surface portions 20a and 20b (see FIG. 4). As will be appreciated from FIG. 4, the respective flat upper surface portions 18a and 18b and convex upper surface portions 20a and 20b are located generally in diametrically opposite quadrants. 
     Referring to FIGS. 1 and 3, the tool 10 includes an elongated shank 22 having an end 24 which is suitably designed to be placed in engagement with the head 12 of the one-way fastener 16 in the form of a pair of fastener-engaging tips 24a and 24b. It will be seen and appreciated that the tips 24a and 24b extend from the shank for engagement with the head 12 of the one-way fastener 16. In addition, the tool 10 includes a double collet generally designated 26 to be positioned on the shank 22 which includes means for adjustably gripping the head 12 of the one-way fastener 10 as will be described in greater detail hereinafter. 
     As perhaps best shown in FIG. 1, the double collet 26 is adapted to be axially adjustably secured to the elongated shank 22 such that counterclockwise rotational movement of the shank 22 causes counterclockwise rotational movement to be imparted to the double collet 26. It will be seen and appreciated by considering FIGS. 1 and 3 that the double collet 26 includes a first collet or collet portion 26a for adjustably positioning the fastener-engaging tips 24a and 24b in relation to a second collet or collet portion 26b so as to thereby cause the second collet or collet portion 26b and the fastener-engaging tips 24a and 24b to both simultaneously engage the head 12 of the one-way fastener 16. As will also be described in detail hereinafter, the second collet or collet portion 26b comprises means for adjustably gripping the head 12 of the one-way fastener 16 together with the fastener-engaging tips 24a and 24b after the fastener-engaging tips have been adjustably positioned using the first collet or collet portion 26a. 
     With regard to the double collet 26, the first collet or collet portion 26a includes a tightening collar 28a threaded onto the double collet 26 with right hand threads and the second collet or collet portion 26b includes a tightening collar 28b threaded onto the double collet 26 with left hand threads. The double collet 26 will be seen to be formed in the preferred embodiment so as to have a radially enlarged central portion 28c which preferably has a knurled outer surface, and the first and second collets or collet portions 26a and 26b will be seen to have a plurality of axially extending slots such as 30a and 30b with the outer surface of the first and second collets or collet portions 26a and 26b having right hand threads and left hand threads as shown at 32a and 32b, respectively. With this structure, the tightening collars 28a and 28b may be threaded onto the first and second collets or collet portions 26a and 26b using respective internal right and left hand threads (not shown) to adequately tighten the double collet 26 on the shank 22 and the head 12 of the fastener 16. 
     In typical collet fashion, the tightening collars 28a and 28b may be threaded onto the respective ones of the first collet or collet portion 26a and second collet or collet portion 26b to cause them to be adjustably secured to the shank 22 and to grip the head 12 of the fastener 16 . The inner surface of the first and second collets or collet portions 26a and 26b may be generally circular in cross-section (or, alternatively, at least the inner surface of the first collet or collet portion 26a may be hexagonal to conform to a hexagonal shaped shank 22) and the outer surface bearing the threads as at 32a and 32b may be slightly tapered to a marginally larger diameter from the respective ends 34a and 34b in a direction toward the intermediate knurled portion 26c. Thus, the inner diameters or dimensions of the first and second collets or collet portions 26a and 26b are reduced as the collars 28a and 28b are threaded onto the threads as at 32a and 32b using the right and left hand threads in a direction toward the intermediate knurled portion 26c. 
     As mentioned above , the inner surface of the first collet or collet portion 26a may be formed to be of a non-circular cross-section which conforms to the hexagonal outer surface of the shank 22 as an alternative structure. Thus, the shank 22 may advantageously be formed to be hexagonal in shape so as to be received in a power tool such as a cordless portable electric screwdriver in which case the inner surface of the first collet or collet portion 26a may similarly be shaped so as to have a hexagonal cross-section. In any event, the inner surface of the first collet or collet portion 26a will be dimensioned so as to receive the shank 22 when the collar 28a is threaded to a loosened position axially spaced from the intermediate knurled portion 26c. 
     Of course, the inner surface of the first collet or collet portion 26a will be dimensioned sufficiently close to the outer dimension of the shank 22 as to be tightly secured to the shank 22 when the collar 28a is threaded to a tightened position axially adjacent the intermediate knurled portion 26c. 
     With regard to the second collet or collet portion 26b of the double collet 26, it will be seen to include fastener gripping means preferably in the form of a plurality of teeth 36 disposed about an inner surface for biting into the head 12 of the one-way fastener 16 for imparting torque thereto. The teeth 36 are preferably each angled for biting engagement of the head 12 of the one-way fastener 16 about a radial line passing through an axis of counterclockwise rotational movement of the double collet 26 as best illustrated in FIG. 2. Accordingly, the collar 28b may be threaded onto the second collet or collet portion 26b to reduce the inner diameter thereby causing the teeth 36 to tightly bite into the head 12 of the one-way fastener 16 by using the left hand threads in a manner similar to that described in connection with the collar 28a. 
     As previously discussed, the double collet 26 has a knurled intermediate segment 28c between the first collet or collet portion 26a and the second collet or collet portion 26b and the respective collars 28a and 28b of the first and second collets or collet portions 26a and 26b are also preferably knurled. The respective knurling particularly accommodates hand tightening as well as tool tightening of the collars 28a and 28b. Moreover, the second collet or collet portion 26b and the corresponding collar 28b preferably use left hand threads so that there is a tendency to further tighten the second collet or collet portion 26b to more deeply imbed the teeth 36 into the head 12 of the one-way fastener 16 during a fastener removal operation. 
     As best shown in FIG. 3, the fastener-engaging tips 24a and 24b each preferably have an angled surfaces which are formed so as to cause them to also bite into the head 12 of the one-way fastener 16 when torque is imparted through counterclockwise rotational movement of the tool 10. If the fastener-engaging tips 24a and 24b and the second collet or collet portion 26b are positioned such that the tips 24a and 24b and the teeth 36 can all bite into the head 12 of the one-way fastener 16, the tool 10 is extremely effective in removing any one-way fastener 16. 
     From the foregoing, it has previously been discussed that the shank 22 can be formed in a hexagonal shape which is highly advantageous for the utilization of a cordless portable electric screwdriver. However, as will also be appreciated, the shank 22 could be made integral with a handle in normally conventional manual screwdriver fashion to provide a unique, improved manual fastener removal tool as well. 
     Also, in the foregoing description, the tool 10 has been described for use with removing a one-way fastener of the type having a generally circular head 12 with a pair of flat upper surface portions 18a and 18b and a pair of convex upper surface portions 20a and 20b. It will be appreciated, however, that the tool 10 has much broader applicability for removing any fastener of the type having a head on a shank which could include, but not be limited to, flat head screws, pan head screws, and the like. For all such applications, the fastener-engaging tips 24a and 24b may be utilized to back the fastener out and/or the second collet or collet portion 26b can be utilized to cause the teeth 36 to bite into the head for complete removal thereof. 
     While in the foregoing there has been set forth a preferred embodiment of the invention, it will be appreciated that the details herein given may be varied by those skilled in the art without departing from the true spirit and scope of the appended claims.