GB1582372A - Morticed shoot-bolt - Google Patents

Description

(54) MORTICED SHOOT-BOLT (71) We, THE GREATER LONDON COUN CIL, of County Hall, London, S.E. 1, a British Body Corporate, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to morticed shootbolts for casement type closures such as doors, intended to keep them in a closed state and to protect them against opening from the other side, or to retain them in an open state as may be required.

Such shoot bolts are normally located adjacent to the opening-edge of a door, usually at its top and bottom. They usually have a manually reciprocable slidable boltshoot held in a casing (or socket or combination of holding pieces) contained and fixed within the door body, which bolt-shoot can be manipulated by a knob protruding permanently or retractably or otherwise accessible on the door-face, and the operative end of the shoot engages into a keep-plate or a keep-socket fixed to an adjacent doorframe or threshold or floor.

However, previously proposed and commonly used inset (or flush or recessed) shootbolts have the casing fixed with screws which have their heads exposed and readily accessible (or even if these screw-heads are apparently concealed they can be easily exposed and removed) on the door face, or have knobs easily removable, and consequently such constructions invite and facilitate tampering with by unauthorised persons such as vandals, and this often results in the fittings being easily dismembered damaged or stolen especially in public utility buildings such as for example schools.

When such bolts are put out of action then a door on which they are mounted cannot be readily and securely closed as designed, and in certain locations a door deprived of effective closing and opening devices also contravenes mandatory fire-precautions.

Therefore, these customary shoot-bolts are not adequate for vulnerable situations and conditions of use.

Accordingly, it is the main object of this invention to provide a morticed shoot-bolt with no fixing screws exposed on the doorface.

According to the invention there is provided a shoot-bolt for inserting in a closure, comprising a reciprocal slidable shoot, a handle including a hand grip, a spigot in which the shoot is screw-ithreadedly engaged and a shield intermediate the spigot and the hand grip, the spigot and part of the shoot lying within the projected area of the shield being concealed by the shield when the shoot-bolt is mounted in a closure.

A morticed shoot-bolt embodying the invention is hereinafter described, by way of example, with reference to the accompanying drawings (in which the bolt is shown as fitted at top of door), in which: Figure 1 shows a side elevation Figure 2 shows a front elevation; Figure 3 shows a top plan view; Figure 4 shows a vertical section through the bolt and door; Figure 5 shows a front elevation of the outer trim of the casing, the outer Dart of knob being cut away for the sake of clarity in the illustration; Figure 6 shows a horizontal section through the bolt and door; Figure 5 shows a front elevation of the outer trim of the casing, the outer part of knob being cut away for the sake of clarity in the illustration; Figure 6 shows a horizontal section through the bolt and door at the knob; and Figure 7 shows a top view of the forendplate on top of door.

In the drawings the keep-sockets as may be required on the threshold or floor for bolts fitted at the bottom of door, are not shown because several existing types of socket can be used for this purpose and will fit the bolt shown.

Referring to the drawings, the morticed shoot-bolt comprises a reciprocable slidable round metal bolt-shoot 1 with a threaded part 2, a relieved end 3, a stopper 4 and a groove 5. There is a hand grip device or knob 6 integral with two shielding flanges 7 and an inner spigot or shank 8 which has a threaded hole 9 to fit the shoot thread 2, and a plain hole 10 containing compression spring 11 and two steel balls 12. A casing 13 has an outer trim 14, two entry grooves 15 for the balls, four recesses 16 for the balls, two screw holes 17 with slotted heads fixing screws 18, first guide hole 19 and second guide hole 20. The forend-plate 21 has guide hole 22 and two screw-holes 23 with two fixing-screws 24 and 25. There is a keep-plate 26 with a shoot-hole 27 and two screw-holes 28 with two fixing screws 29.The length of the bolt-shoot is determined by the required convenience of height of the knob 6 above floor level. The position of the shoot in relation to the door face is determined by the need to minimise any weakening of the door body by a drilled hole 31 for the bolt shoot 1. The inside length of the casing is determined by the required movement of the shoot corresponding to the desirable depth of engagement of the shoot in the keep-plate. Overall. length of the two shielding flanges 7 should be just enough to always cover the face of trim 14 when the knob 6 is moved between its extreme positions. The protrusion of the knob is determined by the convenience of easy pulling the knob down (or up) to open doors in emergency as required by fireprecaution regulations.

For fire-resisting doors, all parts of the bolt have to be made of metal with melting point over 800"C, while for other purposes these parts may be made of other suitable materials. The casing and the knob are shaped for easy casting in simple moulds.

The balls are standard items as used for ball-bearings. For fitting into metal hollow doors the wood-screws 18 would have to be replaced with machine-screws fitting into threaded holes in suitable brackets fixed inside the door; and screws 24 and 25 would have to be replaced with machine-screws.

The bolt is fitted on a door for operation as follows: in the door body 30, a vertical hole 31 is drilled from the door edge down to the point 32, and widened to larger diameter at the entry 33 so to accommodate the movement of stopper 4; mortice 34 is chased out in door-face to receive the casing correspondingly to hole 31; casing 13 is inserted into the mortice 34 and fixed with two screws 18 and machine-grease is applied amply to guide holes 19 and 20. Spring 11 and balls 12 are then inserted into hole 10 and held there with the fingers while the knob shank 8 is entered into casing 13 so that the balls can enter grooves 15, and then the shank is pushed fully into the casing and the balls 12 engage in recesses 16 while the flanges 7 rest tightlv on trim 14.While the knob shank is held firmly in position, using the other hand, the bolt-shoot is inserted into hole 31, passed through guide hole 19 and screwed into the threaded hole 9 fully and until shoot-end 3 enters guide hole 20. A suitable nail is placed in groove 5 (to form a temporary protrusion), and using suitable pliers to firmly hold the shootend and nail, the shoot is turned in and tightened strongly in the threaded connection in the shank 8. Forend-plate 21 is then fitted in customary manner and fixed with one "Posidriv" recess head screw and one "Allen" recess head screw (this complexity of screwing is intended to create difficulties for even persistent but unprepared vandals).

At this stage the bolt is tested for easy movement to and fro while the flanges 7 slide over trim 14 and the balls 12 create enough resistance tension onto the splayed inner edges of the casing so to prevent the shoot moving inadvertently under its own weight when the door is being shaken. The keepplate is fitted correspondingly in customary manner.Thus a fitted bolt is ready for con lenient use and is secure against vandal attack. (This bolt can be fitted on (andtor removed from) the bottom of the door with the same procedure but only when the door is taken off its frame.) When it becomes necessary to remove the bolt from the door (for the bolt at the top of door, the door can remain hanging in the frame whereas for a bolt at the bottom of the door, the door has to be taken out of the frame) the procedure is as follows: the forend-plate is removed (using suitable "Posidriv" screwdriver and "Allen" key for the bolts at top of door); the bolt-shoot is loosened using suitable pliers and nail in groove 5, and then unscrewed with pliers only or by hand and fully removed; the knob 6 is removed with a firm pull by hand, while ensuring that the balls do not fall away; finally, screws 18 are removed using a blade screw-driver and the casing 13 is removed. (The bolt-shoot has a stopper 4 which prevents removal of the shoot before first removing the forend 21 (this is intended to create additional difficulties for any potential vandal attempting to remove the bolt without proper knowledge.)) The bolt shown in the drawings and described above is constructed in a manner which precludes unauthorised tampering with once the bolt is fully fitted in position.

The external appearance of the bolt in position does not suggest how it is fixed nor how it can be dismembered, damaged or removed and thus would discourage and baffle any potential wrongdoer. Therefore, the inset shoot-bolt is virtually vandal-proof or vandal-resistant.

The bolt, having been fitted on a door, would not normally require removal, and it is advisable not to remove it for such customary purposes as periodical re-painting (while the re-painting can be cut to the outer edges of the casing) particularly when it does not need any maintenance. Nevertheless, there may be some rare occasions when it may have to be removed, e.g. to salvage it when the door is to be changed. Therefore, for such legitimate purposes the bolt can be removed.

It will be understood that the embodiment of the invention shown in the drawings and above described can be modified in several ways. For example, the spring 11 and balls 12 could be replaced by any suitable restraining means such as a leaf spring acting on the shank 8.

WHAT WE CLAIM IS:- 1. A shoot-bolt for insetting in a closure, comprising a reciprocable slidable shoot, a handle including a hand grip, a spigot in which the shoot is screw-threadedly engaged and a shield intermediate the spigot and the hand grip, the spigot and part of the shoot lying within the projected area of the shield being concealed by the shield when the shoot-bolt is mounted in a closure.

2. A shoot-bolt according to Claim 1, the shield comprising lateral flanges of the handle.

3. A shoot-bolt according to Claim 1 or Claim 2, including a mechanism mounted in the spigot which tends to resist sliding movement of the shoot.

4. A shoot-bolt according to Claim 3, the mechanism comprising a resilient device tending in use to frictionally engage part of the closure.

5. A shoot-bolt according to Claim 4, the resilient device comprising a ball mounted under spring pressure in a bore of the spigot.

6. A shoot-bolt according to Claim 5, there being two balls with a compression spring between them tending to urge the balls out of the bore.

7. A shoot-bolt according to any preceding claim, comprising a stop on the shoot for limiting, in use, the longitudinal movement.

8. A shoot-bolt for insetting in a closure, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

9. A closure having mounted therein an inset shoot-bolt according to any of the preceding claims.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. (while the re-painting can be cut to the outer edges of the casing) particularly when it does not need any maintenance. Nevertheless, there may be some rare occasions when it may have to be removed, e.g. to salvage it when the door is to be changed. Therefore, for such legitimate purposes the bolt can be removed. It will be understood that the embodiment of the invention shown in the drawings and above described can be modified in several ways. For example, the spring 11 and balls 12 could be replaced by any suitable restraining means such as a leaf spring acting on the shank 8. WHAT WE CLAIM IS:-

1. A shoot-bolt for insetting in a closure, comprising a reciprocable slidable shoot, a handle including a hand grip, a spigot in which the shoot is screw-threadedly engaged and a shield intermediate the spigot and the hand grip, the spigot and part of the shoot lying within the projected area of the shield being concealed by the shield when the shoot-bolt is mounted in a closure.

2. A shoot-bolt according to Claim 1, the shield comprising lateral flanges of the handle.

3. A shoot-bolt according to Claim 1 or Claim 2, including a mechanism mounted in the spigot which tends to resist sliding movement of the shoot.

4. A shoot-bolt according to Claim 3, the mechanism comprising a resilient device tending in use to frictionally engage part of the closure.

5. A shoot-bolt according to Claim 4, the resilient device comprising a ball mounted under spring pressure in a bore of the spigot.

6. A shoot-bolt according to Claim 5, there being two balls with a compression spring between them tending to urge the balls out of the bore.

7. A shoot-bolt according to any preceding claim, comprising a stop on the shoot for limiting, in use, the longitudinal movement.

8. A shoot-bolt for insetting in a closure, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

9. A closure having mounted therein an inset shoot-bolt according to any of the preceding claims.