GB2180290A - Security bolt - Google Patents

Abstract

A security bolt (1) includes a bolt rod (3) slidably mounted in a housing (2) for relative movement between operative and inoperative positions, the rod having a section (3) of reduced cross-section so as to form two opposed shoulders (31,49). Key operated locking mechanism (5), having a rotatable barrel (28) is attached to the housing, and a detent member (25) is rotatably mounted on an end portion of that barrel. The detent member is rotatable to a position at which it engages one of the rod shoulders (31) and thereby prevents movement of the rod (3) out of the operative position. Rotation of the detent member (25) is caused by rotation of the barrel (28), but a lost motion connection (33,34,35) enables the barrel to rotate to a limited extent in either direction without causing corresponding rotation of the detent member. The locking mechanism can be removed from the housing through a rearside (7) and releasable securing means (21,23) controls that removal. A floating member (38) located between the rod shoulders (31,49) is arranged to be trapped between one of those shoulders (31) and an opposed surface (45) of the housing so as to prevent separation of the rod (3) from the housing (2) in one direction. <IMAGE>

Description

SPECIFICATION Security bolt This invention relates to security bolts for doors, windows, and other movable members and is particu larly concerned with such bolts which are releasably lockable in an operative position. It will be convenient to hereinafter describe the invention in relation to doors, but it is to be understood that the invention has other applications.

Security bolts ofthe foregoing kind generally includea rodorbarwhich isslidablymountedina member arranged to be secured to an appropriate support. Keyoperated locking mechanism is operable to releasably secure the rod orbarin a projecting position which is its operative position. An example security bolt of that kind forms the subject of Australian patent 543,872.

The overall size of a security bolt assembly is usually quite small and as a result there is generally little space within which to mountthe locking mechanism.

Because ofthat limitation on space it has usually been the practice to use a dise tumber lock in the mechanism, particularly as such locks can be arranged for 1800 movement ofthe barrel between the locking and release positions. Pin tumbler locks can be similarly arranged, but such locks are usually bulkierthan those relying on 360" movement and for that reason are generally not acceptable for use in security bolt assemblies.

Disc tumbler locks are therefore commonly used in security bolt assemblies and the overall security of such assemblies suffers as a result. In that regard, such locks are generally less resistant to picking an otherforms of manipulation than are pin tumbler locks. Furthermore, disc tumbler locks usually have a relatively small number of combination codes and consequently there is a greater potential for a lock of that kind to be operated by a key not specifically cut for that lock. Also, most domestic locks are ofthe pin tumbler kind so that use of a disotumbler lock in a security bolt assembly disturbs the possibility of having a single keyforall locking mechanisms in a particular situation.

In security bolt assemblies, it is desirable to provide means whereby the rod or bar can be releasably retained, independent ofthe locking mechanism, in eitheran operative or inoperative position. It its further desirable to provide a meanswhereby the rod or bar is positively restrained against separation from the associated mounting member. in the construction according to patent 543,872, the same elementnamely a spring clip -- serves each ofthe foregoing functions and its nature is such that its holding influence can be overcome with relative ease. For example, it is possible to completely withdraw the rod or barfrom the mounting member by applying sufficient axial force to cause the spring clip to be deflected out of its holding position.

An object ofthe present invention is to provide an improved security bolt oftheforegoing kind which has a relatively high level of security. In particular, it is an object to provide such a security bolt with locking mechanism which has greater resistance to improper manipulation than prior arrangements of the same general kind. It is anotherobjectofthe invention to provide such a security bolt which utilises a pin tumbler lock ofthe kind in which the barrel rotates through 3600 between the lockand release positions.

Yet another object is to provide such a security bolt which is effective in operation in any of a wide variety of dispositions. It is a further object of the invention to provide such a security bolt having highly effective means for positively retaining the rod or bar against separation from its mounting. Still another object is to provide an arrangement which enables convenient inclusion of effective locking mechanism.

According to one aspect ofthe present invention, there is provided a security bolt including, a housing, a bolt rod slidably mounted on said housing for movement relative thereto between an operative position and an inoperative position, said rod having an end portion which projects beyond one side of said housing in said operative position and which is substantially contained within said housing in said inoperative position, a detent member mounted on said housing for movement relative thereto between a locking position at which it is operative to prevent movement of said rod from said operative position to said inoperative position and a rest position at which it is not so operative, locking mechanism attached to said housing and including a driving member which is rotatable relative to said housing for movement between locked and unlocked positions, and lost motion means interconnecting said detent and driving members so that the detent member moves between said locking and rest positions in responseto part of said driving member movement and does not so move in response to another part of said driving member movement.

According to anotheraspectofthe present inven- tion, there is provided a security bolt including, a housing, a bolt rod slidably mounted on said housing for movement relative thereto between an operative position and an inoperative position, said rod having an end portion which projects beyond one side of said housing in said operative position and which is substantially contained within said housing in said inoperative position, a detent member mounted on said housing for movement relative thereto between a locking position at which it is operative to prevent movement of said rod from said operative position to said inoperative position anda rest position at which it is not so operative, locking mechanism attached to said housing and being operable to releasablysecure said detent member against movement out ofsaid locking position, and holding means for preventing axial movement of said rod in one direction beyond a predetermined position so as to thereby prevent separation of said rod from said housing, said holding means including a floating memberwhich is slidably mounted on said housing for movement relative thereto in the axial direction of said rod, and said floating member is arranged for limited movement relative to said rod in the axial direction of the rod and prevents said separation by location between and coaction with opposed surfaces of the rod and the housing respectively.

According to yet another aspect of the invention, there is provided a security bolt including, a housing, a bolt rod slidably mounted in said housing for movement relative thereto between an operative position and an inoperative position, said rod having an end portion which projects beyond one side of said housing in said operative position and in which is substantially contained within said housing in said inoperative position, a detent member mounted on said housing for movement relative thereto between a locking position at which it is operative to prevent movement ofsaid rod from said operative position to said inoperative position and a rest position at which it is not so operative, locking mechanism attached to said housing and being operable to releasablysecure said detent member against movement out of said locking position, said locking mechanism having a bodywhich is located within a cavity in said housing and is removable from cavity and said housing and is removable from said cavity and said housing through a rear side of said housing, and a barrel which is mounted on said body rotation about an axis extending transverse to the longitudinal axis of said rod, said cavity is located to one side of said rod and said body is movable into and out of said cavity in the general direction of said barrel rotational axis, means interconnecting said detent member and said barrel whereby said detent member moves in responseto said barrel rotation, and securing means interacting between said housing and said bodyto releasably hold said body against removal from said housing.

An embodiment of the invention is described in detail inthefollowing passages of the specification which refertothe accompanying drawings. The drawings, however, are merely illustrative ofhowthe invention might be put into effect, so that the specific form and arrangement of the various features as shown is not to be understood as limiting on the invention.

In the drawings: Figure lisa front elevation view of a security bolt according to one embodiment ofthe invention, Figure 2 is a side elevation view ofthe security bolt shown in Figure 1, Figure 3 is a rear elevation view ofthe security bolt shown in Figure 1 with parts being sectioned for convenience of illustration, Figure 4 is a cross-sectional view ta ken along line lV-lVofFigure3, Figure 5 is a cross-sectional view taken along line V-V of Figure 3, Figure 6 is a view similarto Figure 3 but showing the bolt in an operative condition, Figure 7 is a view of part ofthe construction shown in Figure 6 but showing the lock mechanism turned through 2700 to a position at which it is operable to thereafter preventwithdrawal ofthe lock boltto an inoperative position, Figure 8 is a view similar to Figure 7 but showing the lock mechanism turned through a further 900 so asto positively prevent withdrawal ofthe lock boltto an inoperative position, Figure 9 isa cross-sectional view taken along line IX-IX of Figure 7, Figures 1 Oto 14 are semi-diagrammatic views which show various arrangements in which the security bolt can be used.

In an example arrangement shown in the drawings, the security bolt 1 includes a housing 2 which is adaptedto be secured to a door, door surround, or other support, and a rod 3 of circular cross-section which is slidably mounted on the housing 2 and formes the actual bolt. The housing 2 can be of any suitable shape, but in the form shown it is an elongate member of substantially rectangular shape in transverse crosssection and having an enlarged section 4 intermediate its ends for containing the locking mechanism 5. That enlarged section 4 projects outwardlyfora suitable distance beyond a front surface 6 ofthe remainder of the housing 2. It is preferred that the housing 2 is hollow and open at a backsurface7to enable access to the interior.

The bolt rod 3 is preferably slidably mounted in the housing 2 so as to project longitudinally thereof adjacent one side 8 ofthe housing 2. Afinger engageable partS ofthe rod 3 is arranged to project beyond one end 10 ofthe housing 2 in both operative and inoperative positions of the rod 3 (Figures 6 and 3 respectively). A strike engaging end portion 11 ofthe rod 3 opposite the finger engageable part 9 projects beyond the other end 12 ofthe housing 2 in the operative position ofthe rod 3 (Figure 6) and is at least substantially withdrawn into the housing 2 in the inoperative position (Figure 3). The slidable mounting for the rod 3 may include, as shown, a cylindrical bore 13 of appropriate diameterformed through each of two opposite end wails 14 and 15 of the housing 2.

Locking mechanism 5 for the rod 3may be of any suitableform but inthe embodiment shown includes a key operated pin tumbler cylinder lock. The lock cylinder or body 16 is locatable within a suitably shaped cavity 17 (Figu re 5) accessible atthe rear ofthe housing 2 so as to be properly positioned relative to the rod 3. That is, at least partofthe cavity 17 may cooperate with the lock body 16 so that the body 16 can have one position only relative to the housing 2. It is preferred that the lock body 16 is simply slid axially into the housing cavity 17 from the rear ofthe housing and abutswith say the front wall 18 ofthe housing 2so as to fix its endwise position.An opening 19 (Figure 5) formed through thefrontwall 18 of the enlarged housing section 4 provides means whereby a key can be inserted into the lock keyway 20 tFigure 1).

Withdrawal of the lock body 1 6through the rear of the housing 2 may be prevented by securing means which includes a plate 21 orthe like which overlies a rearwardly facing shoulder or surface 22 (Figure3) of the lock body 16 and is releasably secured to the housing 2 by a screw 23 or other suitable fastening means. The cavity 17 is located so that the lock 5 is positioned to one side ofthe bolt rod 3 as shown in Figure 1. That is, the rod 3 is located between the lock body 16 and the side wall 24 ofthe housing 1 Any suitable means may be providedwherebythe lock 5 can cooperate with the bolt rod 3 so as to prevent withdrawal of the rod 3from its operative position. In the particular arrangement shown that means includes a detent member 25which is rotatably mounted on a rear end portion ofthe lock body 16 and which has a laterally projecting section 26 adapted to be engageable with the rod 3. A driving member 27 secured to the rear end of the lock barrel 28 (Figure 1) so as to be rotatable therewith, is operable to hold the detent member 25 in a locking position as hereinafter described. That driving member may also serve to holdthedetentmember25 in assemblywith the lock body 16 by overlying a rearwardlyfacing surface 29 (Figure 3) of the detent member 25.

It is preferred, as shown, that the bolt rod 3 is provided with a section 30 of reduced diameter at a location between its ends so asto provide means for cooperating with the detent projecting section 26 which will be hereinafter referred to as the detent finger26. The shoulder31 formed atthe end ofthe reduced section 30 adjacent the strike engaging end portion 11 ofthe rod 3 forms a stop surface31 for engagement with the detent finger 26 and that stop surface 31 may be substantially at right angles relative tothe longitudinal axis ofthe bolt3.Whenthe detent member 25 is in its locking position (Figure 8), the finger 26 protrudes into the groove 32 formed by the reduced section 30 and engages with the cooperable stop surface 31.

The driving member 27 of the lock 5 may have a laterally projecting lug 33, as shown, which engages against an abutment surface 34 ofthe detent member 25 when both the lock and the detent member 25 are in their respective locking positions (Figure 8). Assuming there is no key in the lock S, the barrel 28 will be held against rotation by the tumbler pins (not shown) and the lug 33 and abutmentsurface34engage in such awaythatthedriving member27 holdsthe detent member 25 against rotation away from the engaging stop surface 31 ofthe rod 3.It therefore follows that the rod 3 cannot be moved from the operative position (Figure 6) towards the inoperative position (Figure 3) and the restraint against that movement is of a substantial nature such thatforcing movement ofthe bolt rod 3 is not possible without shearingthetumblerpinsofthelock5.

When itisdesired to release the lock 5 so thatthe rod 3 can be retracted from the operative position, the lock 5 is operated by the appropriate key so thatthe barrel 28 is rotated in a direction such astoturn the lug 33 away (anti-clockwise in Figure 8) from the cooperating abutment surface 34 of the detent member 25. If the lock 5 is of a kind requiring 360 movement of the barrel 28 between locking and unlocking positions, the driving and detent members 27 and 25 may be relatively arranged to allow an appropriate amount of relative rotation between those members 27 and 25.In the example shown, the driving member27 is capable of substantially 270 degree rotation from the position shown in Figure8 before the lug 33 engages another abutment surface 35 of the detent member 25.

Continued rotation of the driving member 27 then causes corresponding rotation ofthe detent member 25 so thatthe detent finger 26 is moved out ofthe path ofthe rod 3 (Figures 3 and 6) and the rod 3 is freed for movement into its inoperative position.

Itwill be appreciated that rotation ofthe lock barrel 28 in the direction opposite (i.e., clockwise) to that last described will cause the driving member 27 to move the detent member 25 back into its locking position (see Figure 7). Such movement is not possible, however, unless the rod 3 is in or near its operative position because the detent member 25 would other wisefoulwith the largerdiametersection 36 ofthe rod 3.

Movement ofthe rod 3 beyond its operative position may be prevented by a part 37 ofthe finger engageable portion 9 engaging the adjacent end 10 ofthe housing 2. Movement in the reverse direction beyond the inoperative position is prevented by holding means which positively holds the bolt 3 against complete separation from the housing 2. In the preferred arrangement shown, that holding means includes a floating member38 which is located within the housing 2 so as to be movable relative thereto in the axial direction ofthe rod 3.The member38 may be of block-like form and located within a guide groove 39 provided within the housing 2 between the front wall section 40 (Figure 4) thereof and the rod 3. It is preferred, but not essential, that the base 41 (Figure 4) ofthe guide groove 39 is close to the surface ofthe largediametersection 36 ofthe rod 3.

Thefloating member38 may have a groove42 (Figure 9) extending in the axial direction ofthe rod 3 so as to receive the reduced diameter section 30 ofthe rod 3. In the assembled condition ofthe security bolt 1 the floating member38 is located between the ends of that reduced diameter section 30 and is captured between that section 30 and the opposed base 41 of the guide groove 39. Thefloating member38 has a length less than that ofthe reduced diameter section 30 ofthe rod 3.Thearrangementis such thatwhenthe rod 3 is retracted towards its inoperative position the stop surface 31 engages the adjacent end 43 of the floating member 38 and thereby pushes that member 38 along the guide groove 39 toward the end 10 of the housing 2.At the inoperative position ofthe rod 3 the opposite end 44 ofthe floating member 38 engages an opposed surface45 (Figure 4) of the housing 2and thereby positively holds the bolt rod 3 againstfurther travel away from the operative position.

The floating member 38 does not hinder movement ofthe rod 3 from the inoperative to the operative position because of its sliding location within the groove 39. When the rod 3 is moved from the Figure 4 position towards the Figure 6 position, the shoulder 49 ofthe rod 3 engagesthe end 440fthe member38 and thereby push es the member 38 towards the position shownforthatmember38in Figure 6.

It is preferred that the floating member 38 is captured against removal from the guide groove 39 when the security bolt 3 is fully assembled. In the arrangement shown, it may be moved laterally into and out ofthat groove 39 through an access opening (not shown) when the lock body 16 is removed from the housing 2, but other arrangements could be adopted to achieve the same result.

Retaining means for releasably holding the bolt rod 3 in its operative and inoperative positions independent of the lock mechanism 5, preferably includes a spring influenced ball detent, as shown in Figure 4.

That ball 46 and its associated spring 47 may be mounted on the housing 2 at a location adjacent the lock mechanism 5 and in such a way thatthe ball 46 is movable in a direction transverse to the axis ofthe bolt rod 3. At the inoperative position ofthe rod 3 the ball 46 may engage within a circumferential groove 48 provided around the rod 3 and in the operative position of the rod 3 the ball 46 preferably engages behind the stop surface 31. The arrangement is such that the rod 3 cannot be moved from eitherthe inoperative or operative position without directly applying an axial force to the rod 3. In particular, the rod 3will not be dislodged from eitherofthose positions by vibration, gravitation forces, or other incidental forces to which the rod 3 may be subjected in use.

A security bolt as described can be used in a wide varietyof circumstances, some of which are shown by Figures 10 to 14 ofthe attached drawings.

Any suitable form of strike can be used with the security bolt. In some cases, as shown by Figures 11, 12 and 14, the strike may be formed byan integral part of a structure with which the bolt is used - e.g., a door surround 50 (Figure 11) having a bore to receive the rod end portion 11. In other cases, such as those shown by Figures 10 and 13, a speciai strike 51 may be secured to the relevant structure.

The particular strike 51 as shown includes a block-like member 52 having a bore (not shown) extending at least partway thereth rough for receiving the strike engaging end portion 11 ofthe rod 3.

Preferably, the bore extends completely through opposite ends 53 and 54 ofthe member 52. A mounting flange 55 having at least one hole 56 therethrough projects laterallyfrom one end ofthe member 52. At least one further mounting hole 57 may beformedthrough tlíe block-like member 52 in a direction transverse to the bore and located to one side ofthat bore.

Itwill be apparent from the foregoing description thatthe security bolt ofthe present invention will be particularly effective in use regardless of its disposition. It is also relevantthatthe bolt rod cannot be removed from its housing unless the security bolt is completelydismantled.

Various alterations, modifications and/or additions may be introduced into constructions and arrangements of parts previously described without departing from the spirit or ambit ofthe invention as defined by the appended claims.

Claims (27)

1. A security bolt including, a housing, a bolt rod slidably mounted on said housing for movement relativethereto between an operative position and an inoperative position, said rod having an end portion which projects beyond one side of said housing in said operative position and which is substantially continued within said housing in said inoperative position, a detent member mounted on said housing for movement relative thereto between a locking position at which it is operative to prevent movement of said rod from said operative position to said inoperative position and a rest position atwhich it is not so operative, locking mechanism attached to said housing and including a driving mechanism attached to said housing and including a driving member which is rotatable relative to said housing for movement between locked and unlocked positions, and lost motion means interconnecting said detent and driving members sothatthe detent member moves between said locking and rest positions in responseto part of said driving member movement and does not so move in response to another part of said driving member movement

2. A security bolt according to claim 1, wherein stop means is operative to prevent said rod moving relative to said housing beyond said operative position thereof.

3. A security bolt according to claim 2, wherein said stop means includes a finger engageable portion of said rod which is located externally of said housing at a side thereof opposite said one side and which is engageable with an external surface of said housing.

4. A security bolt according to any preceding claim,wherein retaining means releasably holds said rod in said operative position independent of the influence of said detent member on said rod.

5. A security bolt according to claim 4, wherein said retaining means releasably holds said rod in said inoperative position.

6. A security bolt according to claim 4 or 5,wherein said retaining means includes a ball mounted on said housing for movement relative thereto, a spring urging said ball towards a rod engaging position, and a recess in said rod within which said ball engages when the rod is in said operative position.

7. A security bolt according to any proceding claim, wherein said locking mechanism includes a rotatable barrel and key releasable tumblers which are operative to prevent rotation of said barrel relative to said housing, and said driving member is connected to said barrel for rotation therewith and so as to be held against movement relative thereto.

8. A security bolt according to claim 7, wherein said detent member is mounted on an end portion of said barrel for rotation relative thereto, and said lost motion means functions to limit the extent of said relative rotation.

9. A security bolt according to claim 8, wherein said detent and driving members are rotatable about a common axis which extends substantiallytransverse to the longitudinal axis of said rod and is laterally spaced from said longitudinal axis.

10. A security bolt according to claim 8 or 9, wherein said driving member is removably connected to said barrel and overlies part of said detent member so as to restrain said detent member against separation from said barrel.

11. A security bolt according to any preceding claim, wherein a shoulder is formed on said rod, said shoulder extends substantially transverse to the longitundinal axis of said rod and faces away from said end portion of the rod, said detent member has a laterally projecting section which is engageable with said shoulder when said detent member is in said locking position, and said driving member is operable to prevent rotation of said detent memberawayfrom said locking position.

12. A security bolt according to any preceding claim, wherein said lost motion means includes two abutment surfaces provided on said detent member and a laterally projecting lug provided on said driving member, a space exists between said abutment surfaces and said lug is located within and is movable through that space so as to engage either of said abutment surfaces according to the direction of rotation of said driving member, and the relative sizes of said space and said lug are such that said driving member is able to rotate through a substantial distance without engaging a said abutment surface and thereby causing corresponding rotation of the detent member.

13. A security bolt according to any preceding claim, wherein said driving member rotates through substantially 360 between said locked and unlocked positions, and said detent member rotates through substantially90 between said locking and rest positions.

14. A security bolt according to claim 11 orany claim appended thereto, wherein said rod is of circular shape in transverse cross-section, said shoulder is formed at one end of a reduced diameter section of said rod, and said retaining means is engageable with said shoulderto releasably hold said rod in said operative position independent of the influence of said detent member.

15. Asecurity bolt according to claim 7 or any claim appended thereto, wherein said locking mechanism includes a body, said barrel is rotatably mounted in said body, said body is slidably located in a cavity formed in said housing and is removable from said cavity and said housing through a rear side of said housing, and securing means operates to releasably hold said body against movement relative to said housing.

16. A security bolt according to claim 15, wherein said securing means includes a securing plate which is removably attached to said housing and which overlies a rearwardlyfacing surface of said body.

17. Asecurity bolt according to claim 15 or 16, wherein said body is of non-circular shape in crosssection transverse to the rotational axis of said barrel, and said cavity has a substantially complementary cross-sectional shape.

18. A security bolt according to any preceding claim, further including holding means for preventing axial movement of said rod in one direction beyond a predetermined position so as to thereby prevent separation of said rod from said housing, said holding means including a floating memberwhich is slidably mounted on said housing for movement relative thereto in the axial direction of said rod, and said floating member is arranged for limited movement relative to said rod in the axial direction ofthe rod and prevents said separation by location between and coaction with opposed surfaces ofthe rod and the housing respectively.

19. A security bolt including, a housing, a bolt rod slidably mounted on said housing for movement relative thereto between an operative position and an inoperative position, said rod having an end portion which projects beyond one side of said housing in said operative position and which is substantially contained within said housing in said inoperative position, a detent member mounted on said housing for movement relative thereto between a locking position at which it is operative to prevent movement of said rod from said operative position to said inoperative position and a rest position at which it is not so operative, locking mechanism attached to said housing and being operable to releasably secure said detent member against movement out of said locking position, and holding means for preventing axial movement of said rod in one direction beyond a predetermined position so as to thereby prevent separation of said rod from said housing, said holding means including a floating memberwhich is slidably mounted on said housing for movement relative thereto in the axial direction of said rod, and said floating member is arranged for limited movement relative to said rod in the axial direction of the rod and prevents said separation by location between and coaction with opposed surfaces of the rod and the housing respectively.

20. A security bolt according to claim 19, wherein said floating member is interposed between a section of said rod and a wall of said housing, said rod section is located between two opposed shoulders ofthe rod which are spaced apart in the axial direction ofthe rod, one said shoulder forms the said rod surface, and said floating member is located between said shoulders and has a length in the axial direction of said rod which is less than the axial separation of said shoulders so that said relative movement between the rod and the floating member is limited by said floating member engaging with one ofthe other of said shoulders.

21. A security bolt according to claim 20, wherein said rod section is cylindrical and said floating member has a part cylindrical groove formed therein which is substantially complementary to the cylindrical shape ofthe rod section and which receives part of that rod section.

22. A security bolt according to claim 20 or 21, wherein said locking mechanism is removable from said housing, said floating member is trapped against removal from its location between said rod and said housing wall while said locking mechanism is in place, and said removal of the locking mechanism exposes an access opening through which said floating member can be removed from said housing.

23. A security bolt according to any one of claims 19 to 22, wherein said detent member engages with said rod surface to prevent movement of said rod out of said operative position.

24. A security bolt according to any one of claims 19 to 23, wherein said floating member is slidably mounted in a guide groove provided in said housing.

25. A security bolt including, a housing, a bolt rod slidably mounted in said housing for movement relative thereto between an operative position and an inoperative position, said rod having an end portion which projects beyond one side of said housing in said operative position and which is substantially contained within said housing in said inoperative position, a detent member mounted on said housing for movement relative thereto between a locking position at which it is operative to prevent movement of said rod from said operative position to said inoperative position and a rest position at which it is not so operative, locking mechanism attached to said housing and being operable to releasablysecure said detent member against movement out of said locking position, said locking mechanism having a body which is located within a cavity in said housing through a rearsideofsaid housing, and a barrel which is mounted on said body for rotation about an axis extending transverse to the longitudinal axis of said rod, said cavity is located to one side of said rod and said body is movable into and out of said cavity in the general direction of said barrel rotational axis, means interconnecting said detent member and said barrel whereby said detent member moves in response to said barrel rotation, and securing means interacting between said housing and said body to releasably hold said body against removal from said housing.

26. A security bolt according to claim 25, wherein said securing means includes a plate which is releasably secured to said housing by a fastening screw and which overlies part of a rearwardlyfacing surface of said body.

27. A security bolt substantially as herein particularly described with reference to what is shown in the accompanying drawings.