Patent Application
20170120977
The present invention relates to an antitheft device that is particularly well suited for use with wheels, e.g., bicycles, motorcycles and automobiles having at least one wheel that can be secured by an unbreakable device passing therethrough.
The loss of a bicycle to theft is an economic loss as well as a substantial inconvenience to the now-stranded cyclist. The loss of a favorite, customized or bicycle of exotic manufacture can also represent a substantial emotional loss from the time and energy associated with selecting just the right combination of features for the rider.
A number of anti-theft devices have been proposed that are intended to secure a bicycle or motorcycle and thereby prevent or impede theft. See, e.g., U.S. Pat. Nos. 3,747,376; 3,908,414; 5,092,142; 5,475,993; 5,487,285; 5,732,577; 5,913,906; 6,820,448; 7,437,898; 7,481,048; 7,712,339; 8,621,898; 8,881,559; US 2014/036233; and U.S. D579,756.
Despite such devices, those individuals with intent continue to find methods and techniques to defeat such anti-theft devices. Many of those techniques include the use of a handheld bolt cutter with hardened cutting jaws, a portable angle grinder or even a conventional hacksaw to cut through the antitheft device. Such cutters fail the target material in tension, but they induce the tension via the lateral component of the wedge-shaped blades. This means that a bolt cutter is a battle between the compressive strength of the cutting blades versus the compressive strength of the locking device. If both have near-equal hardness, it is difficult to predict which one will win. The battle becomes one of the quantum of pressure that can be applied on the device by the cutting jaws.
Typical, commercially available bolt cutters exhibit hardened blades of about 62 HRC and can cut 6 mm 48 HRC wire but only HRC 19 rods of 11 mm. This means why traditional chains of interlinked, connected wire stock, even if hardened and/or made of unique alloys, must be made so large and heavy: the bolt cutter acts on the individual wire stock diameter, not the overall chain width.
Surveillance videos show that members of the public rarely question or interfere with a thief in the act of breaking or cutting through a bicycle locking device, even when obviously using a bolt cutter or cut-off saw. Thus, cyclists cannot rely on help from passersby who might witness acts of theft in progress. The locking device must do more than just buy time—it must actually work.
It would be desirable to have an anti-theft device that was made from a material that could not be cut, melted, ground or drilled with handheld tools.
Some antitheft devices, such as the popular U-shaped devices, are defeated because they are large enough to secure only one wheel and the bike frame to a support. This leaves the other wheel vulnerable to removal and theft unless two such devices are carried and used together. This would double the cost and inconvenience of securing a bicycle against theft.
It would be desirable to have an anti-theft device that was sufficiently long in reach to secure both wheels and the frame to a stationary support.
Many locking systems are designed with a plurality of flat leg segments joined at a riveted joint that allows one leg segment to rotate and stack closely with the adjacent segments so as to fold into a compact unit that can be stored in a seat bag or on a frame clip. Such design considerations are visually appealing to consumers because they are easy to carry. Unfortunately, all of the currently known designs of this type are made from some version of steel, hardened steel or hard aluminum.
While titanium may have been suggested for bicycle locks (see, e.g., US Patent Publication Nos. 2014/0109631 and 2014/0260439), no specific grade or type of titanium is specified.
Titanium is available in various grades, based on the material properties. Commercially pure titanium is available in increasing hardness from Grade 1 to grade 4. These grades of titanium can be formed, engraved with conventional machines, and cut so that they can even be used as rings and similar jewelry. Stronger grades of titanium are alloys that have been mixed with one or more Group III-Group VIII materials (e.g., vanadium, molybdenum, nickel, ruthenium, palladium, chromium, zirconium, molybdenum, and aluminum) to increase their hardness. Sometimes referred to as “aircraft grade” titanium alloys, such materials are so hard that they are almost impossible to engrave, form or cut.
It is an objective of the invention to provide an antitheft device that cannot be cut by handheld bolt cutters.
It is further an objective to provide a portable antitheft device that can be carried on or by a bicycle without materially compromising the weight and handling of the bicycle in transit when so laden.
In accordance with these and other objectives of the invention that will become apparent from the description herein, an antitheft device according to the invention comprises an antitheft device comprising a plurality of interlinked titanium alloy arm members, each of which exhibits a hardness of HRC 30 or more and a cross sectional distance of 8 mm or more.
The security device according to the invention is sufficiently light to be suitable for use with and carried on a bicycle while also exhibiting a high degree of resistance to breach by bolt cutters, saws and angle grinders. Such robust resistance makes the device also suitable for use with motorcycles and automobiles.
The present device uses a plurality of connected extension arm members (the number of which determine the overall length available of the device), a locking arm that has a locking device permanently connected thereto, and a lockable arm with a bore through the leading edge thereof. In use, the leading edge of the lockable arm is inserted into a transverse opening in the lock housing and a leading rod member on the lock device is secured into the lock housing so that it passes through the bore in the leading edge of the lockable arm.
For the present invention, a hard titanium alloy is preferred. One way to measure the hardness of titanium or alloys thereof is with a Rockwell test. Such a test determines the hardness by measuring the depth of penetration of an indenter under a large load compared to the penetration made by a preload. There are different scales, denoted by a single letter, that use different loads or indenters. The result is a dimensionless number noted as HRA, HRB, HRC, etc., where the last letter is the respective Rockwell scale. See Table 1.
Materials tested with the HRC protocol are generally harder than those tested with the HRB protocol. There is, however, some overlap between the upper end of the HRB (100 kg) scale and the lower end of the HRC (150 kg) scale, e.g., an HRB (100 kg) of 97 corresponds generally to an HRC (150 kg) of about 20, and an HRB (100 kg) of 120 corresponds with an HRC (150 kg) of about 55 for non-austenitic steels. (See http://www.woodcousa.com/bhn.pdf.) HRC values of less than 20 are said to have questionable accuracy.
Titanium alloys having a hardness of HRC 30 or more are preferred for use in the present invention, e.g., titanium exhibiting HRC (150 kg) hardness within the range of 30-68 or HRB within the range of 105-120 or more. Even more preferably, the titanium hardness is within the range of HRC (150 kg) 33-50. Such high hardness is generally beyond the ability of hand tools to cut, saw or grind away. Table 1 lists suitable materials and includes unalloyed titanium by way of comparison.
The most preferred titanium for use as the extension members, rivets and spacer elements in the present invention has a hardness of HRC 35 or higher. Such a material can be found in a Grade 5 titanium alloy (Ti-6Al-4V).
The specific shape of the rod member can exhibit a round or rectangular cross section, but a preferred shape exhibits a cross sectional diameter or length of 8 mm or more, preferably a diameter within the range of 10-20 mm. Such a shape and diameter are sufficiently hard and exhibit such a high tensile strength that they are not readily cut by bolt cutters or saws (hand-operated or battery-operated). Such dimensions and hardness are also a visual deterrent for those intent on using a portable angle grinder that may serve as a psychological deterrent and redirect the would-be thief toward other lock systems that do not have such a robust system.
The ultimate tensile strength of the titanium alloy can also be used as an indicator for suitability in the present invention. This tensile strength may help avoid potential variances due to surface absorption of oxygen from annealing. An exemplary listing of the ultimate tensile strengths of various titanium alloys is found in Table 3.
aSolution treated
An ultimate tensile strength of 700 MPa or more (at 20° C.) is preferred for the titanium members and parts use in the present invention. Even more preferable is a tensile strength of about 930 MPA or more.
The specific shape of the rod member can exhibit any number of potential geometric shapes in cross section, e.g., round, triangular, rectangular, hexagonal, octagonal, etc. provided that the cross sectional distance is sufficiently large to be impractical to cut with handheld bolt cutters, e.g., a cross sectional distance of at least 8 mm, preferably a cross sectional distance within the range of 9-20 mm, and even more preferably a cross sectional distance of 10-14 mm. A preferred shape uses commercially available rod stock that exhibits a cross sectional diameter within the range of 8-12 mm.
Turning now to the figures,
An opposing pair of saddle washers 7 have an arcuate side that contacts the round external surfaces of each rod and an opposing flat or planar side that provides a planar interaction surface 8 in which each rod can pivot relative to the rod with which it is connected by rivet 9, e.g., between rod 2 and rod 3. Saddle washers 7 also serve to protect rivets 9 from attack using the connected rods as cutting guides by a saw blade or bolt cutter jaws.
Locked rod member 5 is permanently secured to lock 10. Lockable rod member 2 can become secured by lock 10 when lockable rod 2 is inserted into lock hole 11 and lock mechanism 12 is engaged. See also
As shown in
The outer diameter 28 of spacer 7 may be the same or substantially the same as the rod diameter 18. The rising edges 29 of washer 7 can present a sharp edge for users. First and/or second chamfers 30, 31 can be used to reduce incidents of cutting or snagging at edges 29 while also retaining the security and planar motion features of saddle washers 7 between connected rods.
Within lock body 35, locking member 36 is able to be removed vertically and axially from within lock body 35 by operation of a key (not shown) in keyhole 37 from a secured position 38 to an unsecured position (not shown). Locking member 36 also exhibits a distal pin 39 that engages the transverse bore 14 of lockable rod 2 when in secured position 38 and disengages from rod 2 when moved axially within lock body 35 or removed completely from lock body 35. Secured bushings 40, 41 within lock body 35 are used to center and secured locking member 36 within lock body 35. Preferably, the external surface 42 of locking member 39 and the corresponding internal surfaces 43, 44 of bushings 40, 41 exhibit mating threads that allow locking member 36 to be threaded into and secured within lock body 35.
The foregoing illustrations and descriptions are not intended to serve as limitations on the scope of the appended claims.
Each of the patents and published applications that have been cited herein are hereby incorporated by reference.
