GB2298691A

GB2298691A - Locking of bolts or nuts

Info

Publication number: GB2298691A
Application number: GB9525908A
Authority: GB
Inventors: Lazzaro Groppo
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-03-10
Filing date: 1995-12-19
Publication date: 1996-09-11
Anticipated expiration: 2015-12-19
Also published as: ITTO950178A0; GB9525908D0; DE19605177B4; GB2298691B; DE19605177A1; IT1279160B1; ITTO950178A1

Description

2298691 ANTITHEFT DEVICE The present invention relates to an antitheft

device, suitable for mounting an object onto a base and respectively for releasing said object from the base.

Preferably, the device is applied for mounting a motor vehicle wheel onto the hub.

Several antitheft devices for this aim are already known, said devices being made as nuts or bolts. In these known devices, the accessible portion I C, is associated wi t h an element which is freely rotatable on the nut or bolt, thereby preventing the nut or bolt from being unlocked by using the tools with which a motor vehicle is equipped. For locking and unloc"Cing, a removable block is provided, which block acts as a 'key and is shaped in complementary BAD ONG(NAL 2 manner to the accessible part of the device. For instance, the key has pins which may engage holes in the nut or bolt. The pins and holes may be Droduced in multiple combinations, so that a nut or bolt can be activated only by a specific key.

The known devices can give rise to problem related with the mechanical strenght of the pins and, in the case of the bolt, to size problems.

According to the invention, there is on the contrary provided a device of the aforementioned type, comprising a first element intended, in use, to be fastened to an object and a second, removable element acting as a key, for loc'C\.ing and unlocking the first element. the device being characterized in that: the first element has a head with an end portion of which the outer surface presents a plurality of lobes; the second element Inas an axial cavity of which the inner surface is shaped in complementary manner to the end portion of the first element; the lobate end portion of the first element axially projects froin a cylindrical portion where an annular groove is provided to house a resilient wire ring so shaped as to project from t,:e r.,jve at diametrically opposite location; a third element is provided consisting of a bush arranged to be fitted C) onto the head of the first element and provided its inner surface with an annular groove which engaged by said projecting portions of the ring, on is in BAD OHIGINAL 1 1 order to -lalre the bush freely rotate on the head.

The invention will be better understood with reference to the accompanying drawings, in which:

- Fig.1 is an exploded view, partly in axial cross-section of th e de v i c e according to the invention, in bolt form; - Figs. 2 and 3 are two perspective views; - Ficr. 4 is a,)artial cross-sectional view of the device in working conditions, and - Fig. 5 shows an element of the device in nut form.

Fig to 4 :)ures 1 show a bolt-shaped device 10, having a threaded stem 11 and a head 12 of which portion 13 adiacent to the shank has a complementary shape to a scat provided. on a wheel or other object.

At the side remote from the shank, the head has a cylindrical portion 14 with an annular groove 15 forming a scat for a ring 16 of substantially C) quadrangular shape. A lobate portion 17 (for instance with five lobes) axially projects from the cylindrical zone 14. The lobe positions and shapes will be different for different bolts thus giving C) rise to a plurality of combinations.

A frusto-conical bush 18 can be fitted onto head 12. The bush has an inner surface with an annular groove 19 where ring 16 is housed in operating conditions. Thanks to the characteristics of ring 16, bush 19 freely rotates on the bolt and does not allow ESAD ORIGINAL - 4 the bolt to be locked or unloclked by -,ieans of the usual tools of which the vehicle is equipped. Moreover, due to the frusto-conical shaDe, the clearance between the lobate portion and the inner bush surface is insufficient to allow introduction of tools for actuating the The device further bolt.

20, acting comprises a bloc.

as a key and separated from the bolt. Block 20 has a cylindrical portion 21 with an axial cavity 22 of which the 'L.-.ner airface has lobes 23 complementary to the lobes of portion 17 of the bolt head. '1Ch e re- L maining portion -)' t.,5 hlock has an outer surface C> with polygonal, for instance hexagonal, crosssection, to allow actuation of the block by means of the conventional tools of which the vehicle is equipped, to lock or unlock bolt 1.

The device may also be nade in nut form, as shown in Fig. 5. Nut -10 has a threaded axial cavity 31 and a portion 32 intended to engage a seat in the wheel.

2G Said portion is limited by a flange 34 with an annular groove 35 forming the seat for a ring (not shown) identical with ring 16 shown in Figures 1 to 0 4. The remaining portion 36 has a lobate external surface. Nut 30 is associated with a bush and a key 25 identical with the bush and key shown in Figures 1 to 4.

A structure like that described is intrinsically more robust than a structure with pins. Moreover the BAD ORIGINAL radial size is limited also in embodiment.

Moreover, there is the above mentioned advantage that tile frusto-conical bush does not allow passage 5 of tools for trying to unlock the device.

the nut-shaped BAD ORIGINAL 6 C L A 1 1,1 S 1.- Antitheft device for mounting an object, the device comprising a first element intended, in use, to be fastened to said object, and a second, removable element acting as a key, for locking and unlocking the first element, characterized in that: the first element includes a head with an end portion of which the outer surface has a plurality of lobes. the second element has an axial cavity of which the inner surface is shaped in complementary -,-,ianner to 1- C, the end portion of the first element; the lobate end portion of the first element axially projects from a cylindrical portion where an annular groove is provided which groove forms the seat for a resilient wire ring so shaped as to project from the seat at diametrically opposite locations; a third element is ?rovided which consists of a bush arranged to be fitted onto the head of the first element and having an annular groove in its inner surface which groove is engaged by the projecting ring portions to allow m> CY the bush to freely rotate on the head.

2.- Device as claimed in claim 1, characterized in that the shape and the arrangement of the lobes is individual for each device.

3.- Device as claimed in claim 1 or 2, characterized in that the bush is frusto-conical and the groove is located near its major base.

4.- Device as claimed in claim 3, characterized BAD ORIGINAL in that the minor base of the bush has a li-mited clearance with respect to the end of the lobate portion of C-ie first element head.

5.- Device as claimed in any precedinlo, claim, cliaracterized Jin thett the first element is a lbolt, and the lobate portion is part of the bolt head.

6.- Device as claimed in any of claims 1 to 4, characterized in that the first element is a nut, having a f lange provided wi th the groove and C lj separating the lobate head from a portion intended to engage the object.

7.- Device as claiined in any preceding claim, for C2 mounting a motor vehicle wheel.

C BAD ORIGINAL