Theft-Deterrent Chain Locking Device

When locking bicycles and other portable objects to fixed objects in an attempt to prevent theft, several locking devices have been used, the most common of which is a length of chain and a commercial padlock. Both the chain and the padlock are made of hardened metal to resist cutting or other means of destruction. The padlock shackle is normally similar to that of the chain so that they both will resist an equal amount of destruction. As a result of their similarity in characteristics, the size of the shackle of the lock is such that it cannot pass through a normal link of the chain. To overcome this problem and still use the proper padlock, the chain is provided with one or more larger links, large enough to allow the passage of the padlock shackle.

In use, the chain is normally passed around or through the bicycle or article to be secured and around a hitching post or other fixed object. The padlock shackle is then passed through the larger links and locked. With this manner of attachment, there will often be a large degree of slack allowing relative movement between the article and the object to which it is secured. Where this slack exists, the chain may be more vulnerable to unauthorized removal than if it were maintained in a taut condition.

Slack chains can also permit damage to the secured article and this is particularly problemsome where a chain is used as a safety chain with a towed vehicle. When using a trailer hitch or other towing means for towing a trailer, a safety chain is used to prevent disconnection if the hitch fails. The safety chain must normally be maintained in a slack or loose disposition due to its construction. Because of this, the towed vehicle may swing wildly behind the towing vehicle if the main hitch fails; and this will present a dangerous situation to other traffic on the highway.

With the present invention, an adjustable chain locking device is provided for locking bicycles and other portable objects in a taut condition to secure them from theft and damage. The device includes a body member having two openings or orifices, one for receiving a conventional chain and the other for receiving the shackle of a padlock. The opening for the chain is a cross-shaped or squared orifice which allows the chain to move through the body member; but prevents rotation of the links about the axis of the chain. Thus, alternate links of the chain are maintained in a coplanar orientation within the body member with the intermediate connecting links in a plane generally perpendicular thereto.

The orifice in the body member for receiving the shackle of the padlock intersects one leg of the cross-shaped or squared orifice. When the chain is pulled through to the desired position, the shackle is inserted through its orifice and between two alternate links. The shackle takes up enough of the space between the alternate links and the connecting link to prevent axial movement of the chain through the body member.

When the locking device of the present invention is to be used with a safety chain for towing a vehicle, the shackle member is provided with an extended arm on which the body member of the locking device is slidably mounted. The body member is biased toward the shackle such that in the normal position, the shackle remains in an orifice provides for it in the body member. To operate and lock, the body member is slid on the extended arm away from the shackle and against the biasing force allowing the chain to be inserted in the orifice and pulled through the body member to the desired position. Upon releasing the body member, the biasing force will move the body member back into the intersection with the shackle; thus locking the chain into position.

FIG. 1 is a perspective view of the body member portion of the locking device;

FIG. 2 is a front view of the body member showing a chain locked into place by a padlock;

FIG. 3 is a side view of the locking device as shown in FIG. 2;

FIG. 4 is a front view of a modified embodiment of the present invention wherein the body member is slidably mounted on the shackle of the locking device;

FIG. 5 is a perspective view of an alternate embodiment of the present invention;

FIG. 6 is a front view of the body member shown in FIG. 5 with a chain locked into place by a padlock;

FIG. 7 is a side view of the locking device as shown in FIG. 6; and

FIG. 8 is a plan view of the strip material for forming the body member of FIG. 5.

As shown in FIG. 1, the locking device includes an adjustment control device generally designated by reference numeral 1 and comprising a body member 2. This member is generally cylindrical in shape and provided with a cross-shaped orifice 3 extending along its longitudinal axis for slidably receiving a chain 4. As shown in FIG. 1, the orifice is formed by a single wall surface extending from one side of the body member to the other. The wall surface connects the apices 3' of the cross-shaped opening with curved wall segments. Each apex is disposed at 90.degree. to the adjacent apex to provide the cross-shaped configuration.

As can be seen in FIG. 2, the dimensions of the orifice 3 are only slightly larger than those of links of the chain 4. The shape of the orifice 3 provides a means for preventing the chain links from rotating. The configuration of the orifice 3 also maintains alternate links of the chain in a common plane and the intermediate connecting link in a plane essentially perpendicular thereto. In the drawings, two alternate links are designated by reference numerals 5 and 7 while the intermediate connecting link which is associated with these two alternate links is designated by reference numeral 6.

A second orifice 8 is provided in the body member and extends crosswise to the first orifice 3. The second orifice passes through the wall of the first orifice on opposite sides of and adjacent to one of the apices 3'. This orifice 8 is located a sufficient distance from the center line of the first orifice to allow passage of shackle 9 of a standard padlock 10 without interfering with the connecting link 6. The second orifice is small enough, however, to maintain the shackle in the path of axial movement of the alternate links 5, 7 and thus prevent axial movement of the chain through the body member.

The body member 2 has two flanges 11 and 12 extending therefrom for attachment to a suitable carrier for the locking device. In FIGS. 2 and 3, the carrier is shown as a link 13 of a chain 4. The connection to the link 13 is made by a rivet 14 passing through the link 13 and attached to the flanges 11 and 12.

In operation, the free end of the chain 4 is first passed through or around the object to be secured, for instance a bicycle. It is then passed around an element such as a tree or post to which it is desired to secure the bicycle. After passing the chain in this manner, the free end is inserted into the first orifice 3 of the body member and pulled through to the desired point along the length of the chain. The shackle 9 of padlock 10 is then inserted into the second orifice 8 between two coplanar links 5 and 7 and locked back into the padlock 10. This locks the chain in place about the object and the structure to which the object is being secured. By having this adjustability feature when locking objects to fixed structures, theft becomes more difficult and the possibility of damage due to the object failing is lessened.

Another embodiment of applicant's device uses a spring loaded lock pin as shown in FIG. 4. Here the lock pin includes a shackle 9 with an extended arm portion 15. A stop washer 16 is attached to the end of the arm. The flanges 11, 12 of the body member 2 of the locking device have openings large enough to allow the arm of the shackle to pass through them. In this way the body member is slidably mounted on the extended arm 15 of the shackle.

A helical compression spring 17 circumscribes the extended arm of the shackle between the lock washer 16 and flange 12 of the body member. The spring is biased to force the body member toward the shackle portion of the lock pin. The body member is oriented such that the second orifice 8 is opposite the end 18 of the shackle 9. In the normal position, the body member is forced into a position where the end 18 of the shackle 9 extends through the second orifice 8 and between coplanar links 5 and 7 as described above with reference to the embodiment of the invention shown in FIGS. 1-3. Stop means in the form of a bead 19 is positioned on the extended arm 15 facing the flange 11 to limit the movement of the body member toward the shackle end. The positioning of this bead is at a point on the extended arm to prevent the body jamming onto the shackle end. The chain for use with this device is attached to the extended arm between the flanges 11, 12.

The locking device may be attached between a towing vehicle and a towed vehicle by inserting the chain around or through suitable parts of the framework of both vehicles. Alternatively, one end of the chain may be welded to the framework of the towed vehicle and the body member connected to the chain intermediate its length. The body member 2 is then moved on the extended arm 15 against the bias of the spring 17 to disengage it from the shackle 9. The free end of the chain is then inserted and pulled through the orifice 3 to the desired position. Upon removing the force used to move the body member on the extended arm to thereby open the locking device, the body member will move to its normal position with the shackle positioned in the orifice 8 and the chain locked in position with the desired degree of tautness. By using the adjustable locking device as part of a safety chain when towing a vehicle, more control over the towed vehicle is provided should the primary hitch ever break.

FIGS. 5-8 show a third embodiment of the present invention wherein the body member is made from a single blank of strip material 20. This strip material is shown in FIG. 8 and may, for example, be a low carbon AISI C1010 steel having a thickness of about 0.075 inches and a width of about 0.75 inches. The blank from which the body member of this embodiment of the invention is to be made is formed in a punch press with a first pair of elongated holes 21 and a second pair of holes 22. The blank strip material 20 is bent into the configuration shown in FIGS. 5 and 6 to provide a square shaped opening 23 and a pair of flanges 24. The flanges extend from the opening 23 in spaced relationship with respect to each other.

As shown in FIG. 6, the diagonal distance across the square shaped opening 23 is slightly greater than the width of the chain links 5, 6 and 7 passing through the opening. This configuration prevents rotation of the chain links in the body member while permitting longitudinal sliding therethrough.

The elongated holes 21 in the formed body member are aligned with each other crosswise of the opening 23. As seen from FIG. 7, these holes provide room for insertion of the shackle 9 of the padlock 10. As with the embodiments of FIGS. 1 and 4, the shackle of the padlock will be disposed in the path of axial movement of alternate links of the chain passing through the opening 23.

The body member of the locking device shown in FIGS. 5-8 is attached to one link at the end of a chain by means of a pin 25 extending through the holes 22. These holes, as shown in FIG. 6 align with each other in the flanges 24 after the strip material has been formed into the body member. The link 13 of the chain to which the body member is attached is disposed loosely between the flanges 24 and effectively closes the corner of the opening 23 disposed at the point from which the flanges 24 extend.

With the construction of all embodiments of the invention, the opening 3 or 23 in the body member is configured to receive the chain with the alternate links oriented in planes extending at right angles with respect to each other. This is the normal orientation of the links when the chain is in an extended tensioned position. To hold the chain links in this position, the chain is advantageously covered with a tubular sheath 27. This sheath is made of plastic material and is of a size whereby it conforms to the right-angled orientation of the adjacent links when in their extended condition. The sheath thus holds the links in this orientation; and sliding movement of the links through the orifice of the body member is therefore facilitated. This characteristic of applicant's construction is especially advantageous when the locking device is being removed from the object which was locked. During such removal, the chain being pulled through the body member is normally not under any tension. Therefore, the links would, if it were not for the tubular sheath, tend to rotate and twist with respect to each other. This could result in jamming of the chain as it is being pulled through the body member. The inclusion of the tubular sheath holding the links in their extended right angle orientation prevents this from happening.