GB2197380A - Friction security bolt - Google Patents

Abstract

A sliding bolt 2 is engaged by pushing on the free end and is held by friction ring 53. To release the bolt a key 4 is attached (as shown by a screw-threaded connection) to allow it to be retracted. <IMAGE>

Description

SPECIFICATION Friction security bolt This invention relates to a security bolt, essentially for use on windows in the home security field.

The sliding bolt is a well known and widely used security item that is ineffective, in that it can be opened by anybody.

The friction security bolt uses the simple sliding bolt principle, but utilises continuous friction to restrict the movability of the bolt and a body design that necessitates the use of a key to open it.

This invention will now be described by way of example, with reference to the accompanying drawings: Figure 1 is a plan view showing essential component parts; Figure 2 shows mounting principle on rebated windows or doors; Figure 3 shows alternative mounting for flush windows or doors.

The friction security bolt consists of a body (1) of specific design and a captive bolt (2).

The bolt has three sections, as described below.

The barrel of the bolt is a controlled sliding fit into the body and friction is applied between the two by the friction rings (3) fitted in the annular grooves machined in the barrel.

The friction is such that the bolt will still move, but only by exerting slight pressure by either pushing or pulling.

The lengths of the three sections of the bolt and the axial length of the body are also critical, as shown in the diagrams below:-* L1 is the usable length of the bore of the body (1).

L2 is the length of the barrel (2B) of the bolt (2).

L3 is the distance the bolt (2) can move and also the length of the button (2C) and the latch of the bolt (2).

Figure 4 in the open position the latch (2A) is retracted into the body and the button (2C) is out.

Figure 5 To move to the locked position, the button (2C) is pushed completely into the body (1) and the latch (2A) located into the ferul fitted in the frame.

Figure 6 To unlock the bolt, the special key (4) must be inserted into the body (1), screwed on to the button (2C), then by pulling out the key the bolt is withdrawn.

Security of the unit is shown in Fig. 7 below: When the bolt (2) is pushed fully into the body, the clearance between 'A' dia and 'B' dia, coupled with the resistance given by the friction rings (3), will prevent the bolt being withdrawn, other than with the correct special key.

The keys (4) and bolts (2) and bodies (1) are designed around special truncated threads of various sizes and pitches and. a bolt can only be opened with the correct key.

For example, in Fig. 7, the thread 'A' dia on the bolt (2) must be the same as the thread 'A' dia in the key (4) and 'B' dia in the body (1) must also be bigger than 'C' dia in the key (4), so that the key will enter the body and screw on to the button (2C) of the bolt (2). It can then be withdrawn by pulling out the key.

1. A sliding bolt utilising continuous friction to restrict its movability, with a body design that allows the bolt to be locked without the use of the key, by requires the use of the special key system to unlock it.

2. A sliding bolt as claimed in claim 1, wherein the special key system uses special threads on matching bolts and keys.

3. A sliding bolt as claimed in claim 1 or claim 2, with a specifically sized bore in the body to restrict opening to the use of the correct key.

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

Claims (3)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Friction security bolt This invention relates to a security bolt, essentially for use on windows in the home security field. The sliding bolt is a well known and widely used security item that is ineffective, in that it can be opened by anybody. The friction security bolt uses the simple sliding bolt principle, but utilises continuous friction to restrict the movability of the bolt and a body design that necessitates the use of a key to open it. This invention will now be described by way of example, with reference to the accompanying drawings: Figure 1 is a plan view showing essential component parts; Figure 2 shows mounting principle on rebated windows or doors; Figure 3 shows alternative mounting for flush windows or doors. The friction security bolt consists of a body (1) of specific design and a captive bolt (2). The bolt has three sections, as described below. The barrel of the bolt is a controlled sliding fit into the body and friction is applied between the two by the friction rings (3) fitted in the annular grooves machined in the barrel. The friction is such that the bolt will still move, but only by exerting slight pressure by either pushing or pulling. The lengths of the three sections of the bolt and the axial length of the body are also critical, as shown in the diagrams below:-* L1 is the usable length of the bore of the body (1). L2 is the length of the barrel (2B) of the bolt (2). L3 is the distance the bolt (2) can move and also the length of the button (2C) and the latch of the bolt (2). Figure 4 in the open position the latch (2A) is retracted into the body and the button (2C) is out. Figure 5 To move to the locked position, the button (2C) is pushed completely into the body (1) and the latch (2A) located into the ferul fitted in the frame. Figure 6 To unlock the bolt, the special key (4) must be inserted into the body (1), screwed on to the button (2C), then by pulling out the key the bolt is withdrawn. Security of the unit is shown in Fig. 7 below: When the bolt (2) is pushed fully into the body, the clearance between 'A' dia and 'B' dia, coupled with the resistance given by the friction rings (3), will prevent the bolt being withdrawn, other than with the correct special key. The keys (4) and bolts (2) and bodies (1) are designed around special truncated threads of various sizes and pitches and. a bolt can only be opened with the correct key. For example, in Fig. 7, the thread 'A' dia on the bolt (2) must be the same as the thread 'A' dia in the key (4) and 'B' dia in the body (1) must also be bigger than 'C' dia in the key (4), so that the key will enter the body and screw on to the button (2C) of the bolt (2). It can then be withdrawn by pulling out the key. CLAIMS

1. A sliding bolt utilising continuous friction to restrict its movability, with a body design that allows the bolt to be locked without the use of the key, by requires the use of the special key system to unlock it.

2. A sliding bolt as claimed in claim 1, wherein the special key system uses special threads on matching bolts and keys.

3. A sliding bolt as claimed in claim 1 or claim 2, with a specifically sized bore in the body to restrict opening to the use of the correct key.