CN110331904B

CN110331904B - Improved anti-theft chain device

Info

Publication number: CN110331904B
Application number: CN201810679949.7A
Authority: CN
Inventors: 不公告发明人
Original assignee: Huang Suhuan
Current assignee: Huang Suhuan
Priority date: 2018-06-27
Filing date: 2018-06-27
Publication date: 2020-09-22
Anticipated expiration: 2038-06-27
Also published as: CN110331904A

Abstract

The invention discloses an improved anti-theft chain device, which comprises a chain, the lock comprises a support frame, a cover plate is fixed on the upper end surface of the support frame, a bottom plate is fixed on the lower end surface of the support frame, a sliding groove is formed in the upper end surface of the support frame, a sliding block is connected in the sliding groove in a sliding mode, an inserting groove is formed in the upper end surface of the sliding block, a through hole through which the small disc can penetrate is formed in the cover plate above the inserting groove, a long groove communicated with the through hole and allowing the connecting rod to slide is formed in the right portion of the through hole, a locking mechanism used for locking the sliding block is arranged in the support frame, and a reset mechanism is arranged between the sliding block and the support frame; compared with the traditional anti-theft device, the anti-theft device improves the anti-theft effect.

Description

Improved anti-theft chain device

Technical Field

The present invention relates to an improved anti-theft chain device.

Background

At present, generally all install the anti-theft chain device on the door of hotel, install the anti-theft chain device on the door of hotel at present generally including first fixing base and second fixing base, first fixing base is fixed on the door frame, the second fixing base is fixed on the door body, fixedly connected with chain on the first fixing base, the one end that first fixing base was kept away from to the chain is provided with the tapered end, then be provided with on the second fixing base and be used for the locked groove with tapered end cooperation locking, but this kind of anti-theft chain is when using, in order to make the tapered end enter into the locked groove, the length of chain is generally longer, after the lock is pried open, because the length of chain is longer, so, the door still can be opened certain angle, thereby lawless persons still can break the anti-theft chain device, there is great potential safety hazard.

Disclosure of Invention

In order to solve the problems, the invention designs an improved anti-theft chain device, when the anti-theft device is used, after a lock head is locked with a lock seat, a chain is straightened, namely, no redundant length is available for opening a door, and thus, compared with the traditional anti-theft device, the anti-theft device improves the anti-theft effect.

The purpose of the invention is realized as follows:

the invention relates to an improved anti-theft chain device, which comprises a chain, a fixed seat and a lock seat, wherein the fixed seat is used for being fixed with a door frame, the lock seat is used for being fixed with a door body, one end of the chain is fixed with the fixed seat, the other end of the chain is fixed with a lock head which is used for being matched and locked with the lock seat, the lock head comprises a large disk part positioned above and a small disk part positioned below, the large disk part and the small disk part are connected through a connecting rod, the top of the large disk part is fixed with the chain, a bracket with an inverted U-shaped cross section is fixed on the front end surface of the fixed seat, a vertical groove with an opening at the upper end and allowing the connecting rod to slide in is arranged on the front end surface of the bracket, arc surfaces which can be matched and guided with the connecting rod to facilitate the connecting rod to slide in the vertical groove are arranged on two sides of the opening at the upper end, the upper end face of the support frame is provided with a sliding groove, the sliding groove is connected with a sliding block in a sliding mode, an inserting groove for inserting the small disc portion is formed in the upper end face of the sliding block, a through hole for the small disc portion to penetrate is formed in a cover plate located above the inserting groove, the right portion of the through hole is provided with a long-shaped groove which is communicated with the through hole and can be used for sliding of a connecting rod, a locking mechanism used for locking the sliding block when the sliding block slides to the rightmost end of the sliding groove is arranged inside the support frame, and a reset mechanism used for driving the sliding block to reset after the sliding block is unlocked.

The invention relates to an improved anti-theft chain device, wherein a locking mechanism comprises a clamping hook which is connected to the right part of the upper end surface of a support frame in a front-back sliding manner, a clamping groove which can be matched and clamped with the clamping hook when a sliding block slides to the rightmost end of a sliding groove is arranged on a sliding block, an inclined plane which can be matched and guided with the clamping hook to facilitate the clamping hook to be clamped into the clamping groove is arranged on the sliding block, a first spring which is used for driving the clamping hook to move so as to clamp the clamping hook into the clamping groove is embedded between the clamping hook and the inner side wall of the support frame, a convex block which is used for limiting the sliding position of the clamping hook is arranged in the support frame, a push rod which is used for pushing the clamping hook is penetrated in; after the structure is adopted, after the small disk part of the lock head is inserted into the slot, and when the lock head and the sliding block slide to the rightmost end of the sliding groove, the clamping hook can be clamped into the clamping groove on the sliding block under the action of the first spring, and when a user presses the push rod, the clamping hook can be separated from the clamping groove, and the clamping hook can conveniently realize the unlocking of the sliding block.

The improved anti-theft chain device comprises a support frame, a first spring, a second spring, a clamping hook and a first spring, wherein the support frame is provided with a first blind hole into which one end part of the first spring can be inserted; by adopting such a structure, the first spring can be positioned.

The invention relates to an improved anti-theft chain device, wherein a reset mechanism comprises a sliding rod arranged on the lower end surface of a sliding block, a long hole for the sliding rod to slide is arranged in a supporting frame, a cavity is arranged on the lower end surface of the supporting frame, the lower end of the sliding rod movably penetrates through the long hole and then extends into the cavity, and a second spring used for pushing the sliding block to slide to the leftmost end of a sliding groove is arranged between the sliding rod and the supporting frame; through the setting of canceling release mechanical system, behind locking mechanism unblock slider, the slider can be under the effect of second spring automatic sliding to the leftmost end of spout.

The improved anti-theft chain device comprises a support frame, a first spring, a second spring, a first inserting rod, a second inserting rod, a first locking rod, a second locking rod and a second locking rod, wherein the first inserting rod is partially inserted into the second spring; through the setting of first inserted bar and second inserted bar, can realize the location to the second spring.

The improved anti-theft chain device is characterized in that a pushing mechanism for pushing the lock head out of the slot when the sliding block slides to the leftmost end is arranged on the supporting frame on the left side of the cavity; through the arrangement of the pushing mechanism, when the sliding block slides to the leftmost end, the small disk portion in the lock head can be ejected out of the slot through the pushing mechanism, and therefore convenience can be brought to a user for taking down the lock head from the lock seat.

The improved anti-theft chain device comprises a pushing mechanism, wherein the pushing mechanism comprises a push rod, an annular boss is arranged at the lower end of the push rod, a slide way which can allow the annular boss to vertically slide is arranged on a support frame at the top of a cavity, a sealing plate for sealing the slide way is fixed at the lower end of the slide way, a third spring for pushing the push rod is arranged in the slide way between the annular boss and the sealing plate, a jack which is communicated with a slot and can allow the upper end part of the push rod to be inserted into is arranged in a slide block, the upper end of the push rod movably penetrates through the support frame and then is inserted into the jack, a guide groove which is communicated with the jack and can be matched with the push rod for guiding so as to facilitate the push rod to be inserted into the jack is arranged on the lower end face of the left part of the slide block, a push column which is inserted into the jack so as to facilitate the push rod to be pushed out from the jack; after adopting this kind of structure, the pushing mechanism can be reliably ejecting from the slot with the small disk portion of tapered end, and when the user need lock the tapered end to the lock seat on, promptly after the small disk portion of tapered end inserted in the slot, the jack can be inserted to the ejection post, so, can be ejecting from the jack with the ejector pin to can make the tapered end move to the right with the slider, so that slider and locking mechanism lock.

The improved anti-theft chain device is characterized in that the upper end of the ejector rod is provided with an annular guide surface which can be matched with the inner side wall of the jack for guiding so as to facilitate the insertion of the ejector rod into the jack; through the setting of annular spigot, the upper end of ejector pin can insert in the jack more conveniently.

The improved anti-theft chain device comprises a support frame, a cover plate, a bottom plate and a bolt, wherein the cover plate and the bottom plate are fixed on the support frame through the bolt; by adopting the structure, convenience can be brought to the assembly of the cover plate and the bottom plate.

The improved anti-theft chain device comprises a fixed seat, a door body, a base plate and a bolt hole, wherein the fixed seat is provided with a first bolt hole through which a bolt can penetrate to conveniently fix the fixed seat on the door body; after adopting this kind of structure, after the screw passes first bolt hole, can conveniently be fixed the fixing base to the door frame, after the screw passes the second bolt hole, can conveniently be fixed the bottom plate to the door body on, can conveniently be fixed the lock seat to the door body promptly.

By adopting the structure, after the lock head and the lock seat are locked, the chain is straightened, namely, no redundant length on the chain can be used for opening the door, so that the anti-theft device improves the anti-theft effect compared with the traditional anti-theft device.

Drawings

FIG. 1 is a schematic top view of a lock base;

FIG. 2 is a partial cross-sectional structural schematic view of the lock housing;

FIG. 3 is a schematic cross-sectional view of the lock housing;

FIG. 4 is a schematic cross-sectional view of the lock cylinder engaged with the lock base;

FIG. 5 is a schematic view of the structure of the fixed base, the chain and the lock after being connected;

FIG. 6 is an enlarged view of the structure at A in FIG. 2;

FIG. 7 is an enlarged view of the structure at B in FIG. 2;

FIG. 8 is an enlarged view of the structure of FIG. 3 at C;

FIG. 9 is an enlarged view of D of FIG. 4;

fig. 10 is a schematic top view of the fixing base.

Detailed Description

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

An improved anti-theft chain device comprises a chain 1, a fixed seat 2 fixed with a door frame and a lock seat 3 fixed with the door frame, one end of the chain 1 is fixed with the fixed seat 2, the other end of the chain 1 is fixed with a tapered end 4 matched and locked with the lock seat 3, the tapered end 4 comprises a large disc part 41 positioned above and a small disc part 42 positioned below, the large disc part 41 and the small disc part 42 are connected through a connecting rod 43, the top of the large disc part 41 is fixed with the chain 1, a bracket 22 with an inverted U-shaped cross section is fixed on the front end surface of the fixed seat 2, a vertical groove 23 with an opening at the upper end is arranged on the front end surface of the bracket 22, an arc-shaped surface 24 matched and guided with the connecting rod 43 to facilitate the sliding of the connecting rod 43 into the vertical groove 23 is arranged on two sides of the opening at the upper end of the vertical groove 23, a containing cavity 25 is formed between the inner side, the lock seat 3 comprises a support frame 31, a cover plate 32 is fixed on the upper end surface of the support frame 31, a bottom plate 33 is fixed on the lower end surface of the support frame 31, a sliding groove 311 is arranged on the upper end surface of the support frame 31, a sliding block 34 is connected in the sliding groove 311 in a sliding manner, an inserting groove 341 into which the small disk part 42 can be inserted is arranged on the upper end surface of the sliding block 34, a through hole 321 through which the small disk part 42 can pass is arranged on the cover plate 32 above the inserting groove 341, a long groove 322 which is communicated with the through hole 321 and can be used for allowing the connecting rod 43 to slide is arranged at the right part of the through hole 321, a locking mechanism for locking the sliding block 34 when the sliding block 34 slides to the rightmost end of the sliding groove 311 is arranged in the support frame 31, and a reset mechanism for; the locking mechanism comprises a hook 51 which is connected to the right part of the upper end face of the support frame 31 in a front-back sliding manner, a clamping groove 342 which can be matched and clamped with the hook 51 when the slider 34 slides to the rightmost end of the sliding groove 311 is arranged on the slider 34, an inclined plane 343 which can be matched and guided with the hook 51 to facilitate the hook 51 to be clamped into the clamping groove 342 is arranged on the slider 34, a first spring 52 which is used for driving the hook 51 to move so as to enable the hook 51 to be clamped into the clamping groove 342 is embedded between the hook 51 and the inner side wall of the support frame 31, a convex block 312 which is used for limiting the sliding position of the hook 51 is arranged in the support frame 31, a push rod 53 which is used for pushing the hook 51 is arranged in the support frame 31 in a penetrating manner, a sleeve part 531 which is sleeved outside the; by adopting the structure, after the small disk part of the lock head is inserted into the slot, and when the lock head and the sliding block slide to the rightmost end of the sliding groove, the clamping hook can be clamped into the clamping groove on the sliding block under the action of the first spring, and when a user presses the push rod, the clamping hook can be separated from the clamping groove, and the clamping hook can conveniently realize the unlocking of the sliding block; the supporting frame 31 is provided with a first blind hole 313 into which one end part of the first spring 52 can be inserted, and the hook 51 is provided with a second blind hole 511 into which the other end part of the first spring 52 can be inserted; by adopting the structure, the first spring can be positioned; the reset mechanism comprises a sliding rod 344 arranged on the lower end face of the sliding block 34, an elongated hole 314 which can be used for the sliding rod 344 to slide is arranged in the supporting frame 31, a cavity 315 is arranged on the lower end face of the supporting frame 31, the lower end of the sliding rod 344 movably penetrates through the elongated hole 314 and then extends into the cavity 315, and a second spring 6 which is used for pushing the sliding block 34 to enable the sliding block 34 to slide to the leftmost end of the sliding groove 311 is arranged between the sliding rod 344 and the supporting frame 31; through the arrangement of the reset mechanism, after the locking mechanism unlocks the sliding block, the sliding block can automatically slide to the leftmost end of the sliding groove under the action of the second spring; a first insertion rod 316 partially inserted into the second spring 6 is arranged on the inner wall of the supporting frame 31, and a second insertion rod 345 partially inserted into the second spring 6 is arranged on the right end surface of the sliding rod 344; the second spring can be positioned by arranging the first inserting rod and the second inserting rod; the supporting frame 31 at the left side of the cavity 315 is provided with a pushing mechanism for pushing the lock head 4 out of the slot 341 when the sliding block 34 slides to the leftmost end; through the arrangement of the pushing mechanism, when the sliding block slides to the leftmost end, the pushing mechanism can push out the small disk part in the lock head from the slot, so that convenience can be brought to a user for taking down the lock head from the lock seat; the pushing mechanism comprises a top rod 71, an annular boss 711 is arranged at the lower end of the top rod 71, a slide way 317 for the annular boss 711 to vertically slide is arranged on the support frame 31 at the top of the cavity 315, a sealing plate 72 for sealing the slide way 317 is fixed at the lower end of the slide way 317, a third spring 73 for pushing the top rod 71 is arranged in the slide way 317 between the annular boss 711 and the sealing plate 72, a jack 346 which is communicated with the slot 341 and into which the upper end part of the top rod 71 can be inserted is arranged in the slider 34, the upper end of the top rod 71 movably penetrates through the support frame 31 and then is inserted into the jack 346, a guide groove 347 which is communicated with the jack 346 and can be matched with the top rod 71 for guiding so as to facilitate the insertion of the top rod 71 into the jack 346 is arranged on the lower end surface of the small circular disc part 42, a pushing column 44 which is inserted into the jack 346 so as to facilitate the pushing of the top rod 71 out from the, the cavity 25 can be used for sliding the small disc part 42 and the push column 44; by adopting the structure, the pushing mechanism can reliably push out the small disk part of the lock head from the slot, and when a user needs to lock the lock head on the lock seat, namely after the small disk part of the lock head is inserted into the slot, the pushing column can be inserted into the jack, so that the ejector rod can be pushed out from the jack, and the lock head with the sliding block can move rightwards, so that the sliding block is locked with the locking mechanism; the upper end of the top rod 71 is provided with an annular guide surface 712 which can be matched with the inner side wall of the insertion hole 346 for guiding so as to facilitate the insertion of the top rod 71 into the insertion hole 346; through the arrangement of the annular guide surface, the upper end of the ejector rod can be more conveniently inserted into the jack; the cover plate 32 and the bottom plate are fixed on the support frame 31 through bolts 35, and countersunk holes 331 for the bolts 35 to be embedded are formed in the bottom plate 33; by adopting the structure, convenience can be brought to the assembly of the cover plate and the bottom plate; a first bolt hole 21 through which a screw can pass to conveniently fix the fixing seat 2 to a door frame is formed in the fixing seat 2, and a second bolt hole 332 through which a screw can pass to conveniently fix the bottom plate 33 to a door body is formed in the bottom plate 33; by adopting the structure, the fixing seat can be conveniently fixed on the door frame after the screw passes through the first bolt hole, and the bottom plate can be conveniently fixed on the door body after the screw passes through the second bolt hole, namely the lock seat can be conveniently fixed on the door body; when the lock is installed, the fixed seat is fixed with the door frame, the lock seat is fixed with the door body, and when the lock seat is fixed with the door body and a lock head needs to be ensured to be locked with the lock seat, the chain can be in a straightening state, namely, a small disc part in the lock head is inserted into the slot, the sliding block slides to the rightmost end, and when the sliding block is locked with the locking mechanism, the chain can be in the straightening state; when the locking device is used, when the locking head and the lock base are required to be locked, the small disk part of the locking head penetrates through the through hole and then is inserted into the slot, the ejector rod is pushed out of the jack under the action of the push column, then the locking head moves rightwards, the sliding block is driven by the locking head to move rightwards, when the sliding block moves to the rightmost end, the clamping hook locks the sliding block, the lock chain is straightened, and the small disk part on the locking head cannot be separated from the long-shaped groove, so that the locking of the locking head and the lock base is realized; when the lock head and the lock seat need to be unlocked, the push rod is pressed down, the clamping hook is separated from the clamping groove on the sliding block, at the moment, the sliding block moves leftwards under the action of the second spring, the ejector rod can gradually slide into the guide groove and is pressed downwards by the guide groove in the leftward movement process of the sliding block, when the sliding block continues to move leftwards to the leftmost end, the ejector rod can move to the position below the jack, at the moment, the upper end of the ejector rod can be inserted into the jack under the action of the third spring, at the moment, the small disk part on the lock head can be ejected out from the slot, therefore, convenience can be brought to a user for taking the lock head off the lock head from the lock seat, and when the lock head is taken off from the lock seat, the lock head and the lock seat can; after the tapered end and the lock seat are unlocked, the connecting rod in the tapered end slides into the vertical groove of the support, and the small disc part and the pushing column can slide into the sliding cavity at the moment, so that the tapered end can be temporarily stored, the phenomenon that the lock chain and the tapered end are clamped between the door frame and the door body in the opening and closing process of the door body can be avoided, and the door body and the door frame as well as the damage to the lock chain and the tapered end can be avoided.

It should be noted that, in the above embodiments, as long as the technical solutions can be aligned and combined without contradiction, those skilled in the art can exhaust all possibilities according to the mathematical knowledge of the alignment and combination, and therefore, the invention does not describe the technical solutions after alignment and combination one by one, but it should be understood that the technical solutions after alignment and combination have been disclosed by the invention.

It should be noted that the above list is only one specific embodiment of the present invention. It is obvious that the invention is not limited to the above embodiments, but that many variations are possible.

In general, all modifications that can be derived or suggested by those skilled in the art from the disclosure herein are intended to be included within the scope of the invention.

Claims

1. The utility model provides a follow-on anti-theft chain device, includes chain (1), is used for fixing with the door frame fixing base (2) and is used for with the fixed lock seat (3) of a body, chain (1) one end is fixed with fixing base (2), chain (1) other end is fixed with and is used for tapered end (4) with lock seat (3) cooperation locking, its characterized in that: the lock head (4) comprises a large disc part (41) positioned above and a small disc part (42) positioned below, the large disc part (41) and the small disc part (42) are connected through a connecting rod (43), the top of the large disc part (41) is fixed with the chain (1), a bracket (22) with an inverted n-shaped cross section is fixed on the front end face of the fixed seat (2), a vertical groove (23) with an open upper end is arranged on the front end face of the bracket (22) and can be used for the connecting rod (43) to slide in, two sides of an opening at the upper end of the vertical groove (23) are respectively provided with an arc-shaped face (24) which can be matched with the connecting rod (43) to guide so that the connecting rod (43) can slide in the vertical groove (23), a containing cavity (25) is formed between the inner side of the bracket (22) and the fixed seat (2), the lock seat (3) comprises a support frame (31), and a cover plate (32) is fixed on the upper end, a bottom plate (33) is fixed on the lower end surface of the support frame (31), a sliding groove (311) is arranged on the upper end surface of the support frame (31), a sliding block (34) is connected in the sliding groove (311) in a sliding way, an inserting groove (341) for the small disk part (42) to insert is arranged on the upper end surface of the sliding block (34), a through hole (321) for the small disk part (42) to pass through is arranged on the cover plate (32) positioned above the inserting groove (341), the right part of the through hole (321) is provided with a long groove (322) which is communicated with the through hole (321) and can be used for the connecting rod (43) to slide, a locking mechanism for locking the sliding block (34) when the sliding block (34) slides to the rightmost end of the sliding groove (311) is arranged in the supporting frame (31), a reset mechanism which is used for driving the sliding block (34) to reset after the sliding block (34) is unlocked by the locking mechanism is arranged between the sliding block (34) and the supporting frame (31); the locking mechanism comprises a clamping hook (51) which is connected to the right part of the upper end face of the support frame (31) in a front-back sliding manner, a clamping groove (342) which can be matched and clamped with the clamping hook (51) when the sliding block (34) slides to the rightmost end of the sliding groove (311) is arranged on the sliding block (34), an inclined plane (343) which can be matched and guided with the clamping hook (51) to facilitate the clamping hook (51) to be clamped into the clamping groove (342) is arranged on the sliding block (34), a first spring (52) which is used for driving the clamping hook (51) to move to enable the clamping hook (51) to be clamped into the clamping groove (342) is embedded between the clamping hook (51) and the inner side wall of the support frame (31), a convex block (312) which is used for limiting the sliding position of the clamping hook (51) is arranged in the support frame (31) in a penetrating manner, a push rod (53) which is used for pushing the clamping hook (51) is arranged in a, the outer end part of the push rod (53) movably penetrates through the support frame (31) and then extends out of the support frame (31).

2. The improved anti-theft chain device according to claim 1, characterized in that the supporting frame (31) is provided with a first blind hole (313) into which one end portion of the first spring (52) can be inserted, and the hook (51) is provided with a second blind hole (511) into which the other end portion of the first spring (52) can be inserted.

3. The improved anti-theft chain device according to claim 1, wherein the reset mechanism comprises a sliding rod (344) arranged on the lower end surface of the sliding block (34), an elongated hole (314) for the sliding rod (344) to slide is arranged in the support frame (31), a cavity (315) is arranged on the lower end surface of the support frame (31), the lower end of the sliding rod (344) movably penetrates through the elongated hole (314) and then extends into the cavity (315), and a second spring (6) for pushing the sliding block (34) to enable the sliding block (34) to slide to the leftmost end of the sliding groove (311) is arranged between the sliding rod (344) and the support frame (31).

4. The improved anti-theft chain device according to claim 3, characterized in that a first inserted rod (316) partially inserted in the second spring (6) is provided on the inner wall of the supporting frame (31), and a second inserted rod (345) partially inserted in the second spring (6) is provided on the right end face of the sliding rod (344).

5. The improved anti-theft chain device according to claim 3 or 4, characterized in that the supporting frame (31) at the left side of the cavity (315) is provided with an ejecting mechanism for ejecting the lock head (4) out of the slot (341) when the sliding block (34) slides to the leftmost end.

6. The improved anti-theft chain device according to claim 5, wherein the pushing mechanism comprises a top rod (71), an annular boss (711) is arranged at the lower end of the top rod (71), a slide way (317) capable of allowing the annular boss (711) to vertically slide is arranged on the support frame (31) at the top of the cavity (315), a sealing plate (72) used for sealing the slide way (317) is fixed at the lower end of the slide way (317), a third spring (73) used for pushing the top rod (71) is arranged in the slide way (317) between the annular boss (711) and the sealing plate (72), a jack (346) communicated with the slot (341) and capable of allowing the upper end part of the top rod (71) to be inserted is arranged in the slide block (34), the upper end of the top rod (71) movably penetrates through the support frame (31) and then is inserted into the jack (346), and the lower end surface of the left part of the slide block (34) is provided with a jack (346) which is communicated with the jack (346) and capable of being matched The small disc part convenient for the ejector rod (71) to be inserted into the guide groove (347) of the insertion hole (346), a push column (44) which is used for being inserted into the insertion hole (346) to push the ejector rod (71) out of the insertion hole (346) conveniently is arranged on the lower end face of the small disc part (42), the height of the push column (44) is the same as the depth of the insertion hole (346), and the accommodating cavity (25) can be used for the small disc part (42) and the push column (44) to slide in.

7. The improved anti-theft chain device according to claim 6, characterized in that the upper end of the top bar (71) is provided with a ring-shaped guide surface (712) which can be guided in cooperation with the inner side wall of the insertion hole (346) to facilitate the insertion of the top bar (71) into the insertion hole (346).

8. The improved anti-theft chain device according to claim 1, characterized in that the cover plate (32) and the base plate are fixed to the support frame (31) by means of bolts (35), and the base plate (33) is provided with counter bores (331) in which the bolts (35) can be inserted.

9. The improved anti-theft chain device according to claim 1, characterized in that the fixing seat (2) is provided with a first bolt hole (21) for passing a screw to fix the fixing seat (2) to a door frame, and the bottom plate (33) is provided with a second bolt hole (332) for passing a screw to fix the bottom plate (33) to a door body.