GB2351760A - Lock mechanism with self-adjusting keep - Google Patents

Abstract

A self-adjusting lock keep includes a base 117 for attachment to a first component such as a window frame and an engagement surface 111 with ribs 120 maintained spaced apart from said base for being received by and for engaging with a lock member on a second component, such as a window sash, along a closure axis substantially parallel with said engagement surface. The distance between the engagement surface 111 and the base 117 is automatically variable in a direction substantially orthogonal to the closure axis by a variable length support post 136,137. Mis-registration or misalignment between the first and second components in a direction orthogonal to the closure axis is thereby compensated. The lock member can engage/disengage with the keep ribs by transverse movement parallel to the ribs. Alternatively the ribs can be formed as ratchet teeth for latching engagement.

Description

2351760 SELF-ADJUSTING LOCK KEEP The present invention relates to locking

mechanisms for releasably locking two components together, which components are normally in sliding relationship to one another at the time of engagement or disengagement. In particular, though not exclusively so, the invention relates to window and door locking mechanisms.

In modern window and door manufacture, it is desirable to provide opening windows or doors with locking or latching mechanisms which provide for secure complete closure with high resistance to forced entry, and preferably also to provide for secure partial closure or latching of the window or door in, for example, a so-called "ventilation" position. Partial closure mechanisms are generally particularly vulnerable to attempted forced entry.

It is also desirable to provide such locking or latching mechanisms such that they can be integrated with a multi-point locking system as commonly found in modern PVC window and door styles, where multiple locking mechanisms around the window sash are connected to actuator drive rods driven by a single actuator handle.

It is an object of the present invention to provide an improved locking and latching mechanism which gives a high degree of security in both a fully closed and multiple "ventilation" positions, and which can be readily adapted to integrate with multi-point locking mechanisms.

It is a farther object of the present invention to provide an improved locking mechanism which can be easily installed in window sashes 1 incorporating industry standard (eg. "Euro-groove") sash profiles for full compatibility and inter-operability with other actuating mechanisms and window furniture.

It is a further object of the present invention to provide an improved locking mechanism which is self-adjusting and therefore provides for an extended degree of variability in the alignment or registration of the mating lock components.

The present invention is applicable to various types of windows and doors, including casement types and tilt-and-turn types.

According to one aspect, the present invention provides a self-adjusting lock keep comprising: a base for securing the lock keep to a first component; and an engagement surface maintained spaced apart from said base for being received by and for engaging with a lock member secured to a second component, along a closure axis substantially parallel with said engagement surface, the distance between the engagement surface and the base being automatically variable in a direction substantially orthogonal to the closure axis.

According to another aspect, the present invention provides a locking mechanism comprising: a rack member, for attachment to a first component, the rack member having an engagement surface including a first plurality of substantially parallel ribs extending along the surface in a first direction, a base for attachment of the rack member to the first component, and a support post between the engagement surface and the base, which support post is variable in length; a lock member, for attachment to a second component which is to be releasably secured to 2 the first component by said locking mechanism, the lock member including an engagement surface having a second plurality of substantially parallel ribs adapted to engage with at least some of the first plurality of ribs on said first engagement surface; means for maintaining said engagement surfaces of said rack member and lock member in overlying relationship to lock together said first and second components; and means for disengaging said rack member and said lock member by providing relative movement of said rack member and lock member in a direction substantially parallel to said ribs until said first and second plurality of ribs disengage, so as to disengage said first and second components.

Embodiments of the present invention will now be described by way of example and with reference to the accompanying drawings in which:

Figure 1 shows a cross-sectional view through a window sash, window frame and locking device; Figure 2 shows a rack member in which: figure 2a shows a front perspective view, figure 2b shows a rear perspective view, figure 2c shows a front view, figure 2d shows a rear view, figure 2e shows an end elevation, and figure 2f shows a cross-sectional view on line A-A of figure 2c; Figure 3 shows detail of the rack member of figure 2 including:

tooth orientation in front view (figure 3a), and tooth profile in side view (figures 3b and 3c); Figure 4 shows a housing member in which: figure 4a shows a front view, figure 4b shows a cross-sectional view on line B-B of figure 4a, figure 4c shows a receiving end view, and figure 4d shows an opposite end view to figure 4c; 3 Figure 5 shows a lock member in which: figure 5a shows a front view, figure 5b shows a side view and figure 5c shows a rear view; Figure 6 shows a leaf spring for use with the lock member of figure 5; and Figure 7 shows the same cross-sectional view of figure 1, but with the window sash and frame in varying positions in relation to one another corresponding to (a) window open with lock mechanism disengaged, (b) window in ventilation position with lock mechanism engaged, and (c) window fully closed; Figure 8 shows an exploded perspective view of a self-adjusting lock keep to replace the rack member of figure 2; Figure 9 shows the self-adjusting lock keep of figure 8 in its fully extended or "top" position, in which: figure 9a shows a front perspective view, figure 9b shows a front view, figure 9c shows an isometric cross-sectional view on line A-A of figure 9b; figure 9d shows an isometric cross-sectional view on line B-B of figure 9b; figure 9e shows an end elevation; figure 9f shows a cross-sectional end elevation on line C-C of figure 9b; figure 9g shows a cross-sectional view on line A-A of figure 9b; and figure 9h shows a cross-sectional view on line B-B of figure 9b; Figures 10a to 10h show exactly correspondent views to those of figures 9a to 9h, except with the lock keep in its half-extended, or "midway" position; Figures 1 la to 1 1h show exactly correspondent views to those of figures 9a to 9h, except with the lock keep in its fully compressed, or "bottom" position; 4 Figures 12a to 12h show, respectively, rear, leading end, front, trailing end, leading rear perspective, trailing rear perspective, front perspective and side views of the locking strip of figures 8, 9 and 10; Figures 13a to 13g show, respectively, rear perspective, front 5 perspective, rear, front, trailing end, side and cross-section on a-a views of the fixing plate of figures 8, 9 and 10.

Referring now to figure 1, there is shown a lock assembly installed as a window lock.

A window frame 1, of a standard profile adapted to receive various items of window furniture and typically manufactured of PVC, may correspond to the top, bottom or either side of the window, dependent upon hinging arrangements. A window sash 2, also of a standard profile adapted to receive various items of window furniture, is shown in closed position adjacent to the window frame.

In an outward opening window, surface 3 corresponds to the outside of the window frame, and surface 4 corresponds to the outside of the window sash, with channel 5 carrying a rubber seal (not shown) for compressing against outer surface 3 of the frame profile to form a weather-tight seal, and channel 6 carrying a rubber seal (not shown) for compressing against a glazing unit (not shown) installed against inner wall 7.

The locking mechanism comprises a rack member 10, a lock housing member 30 and a lock member 50 which are shown in more detail in figures 2, 4 and 5 respectively.

With reference to figures I and 2, the rack member comprises a strip I I which includes, on a front surface thereof, a plurality of parallel ribs 12 which extend across a part of the front surface hereinafter referred to as the engagement surface 14. The remainder of the front surface is relatively smooth and provides what is hereinafter referred to as the disengagement surface 15.

The strip I I is supported adjacent the window frame profile I by a support post 16 which, as best viewed in figure 2f, extends upwards from a fixing plate 17 to a proximal end of the strip 11. The support post 16 is affixed to the window frame 1 using known techniques.

Throughout the present specification, the free end (distal end) 18 of the strip 11 will be referred to as the leading end, and the end 19 proximal to the support post will be referred to as the trailing end.

The ribs 12 comprise a series of teeth 20, best viewed in figure 3, which teeth have a leading edge profile 21 which is preferably moderately inclined with respect to the plane of the engagement surface 14. In a preferred embodiment, the angle between the plane of the engagement surface 14 and the tooth leading edge 21 is approximately 40'. The teeth 20 preferably have a trailing edge profile 22 which is perpendicular or near perpendicular to the plane of the engagement surface 14. In a preferred embodiment, particularly as shown in figure 3c, the trailing edge profile is re-entrant. In other words, the top comer of the tooth 20 overhangs an edge of the base of the tooth, and preferably the angle between the trailing edge profile 22 and the plane of the engagement surface 14 is approximately 94', ie. 4' from orthogonal.

6 It will be understood that the trailing edge profile may include a reentrant profile only over a part of the height of the tooth Preferably, the teeth 20 have rounded comers as exhibited in figure 3c, 5 tooth 20a, rather than angular corners as exhibited in figure 3c, tooth 20b.

The teeth 20 each have a longitudinal axis which is transverse to the axis of the strip (ie. the strip axis which extends between the leading end 18 and the trailing end 19). In a preferred embodiment as shown in figure 3a, the teeth axes are slightly off-perpendicular to the strip axis, preferably approximately 6' off perpendicular.

Preferably, the strip 11 is formed from a resilient plastics material, such 15 as Nylon 6,6, with or without glass or spring steel reinforcement, or from Kevlar". Many alternative materials may be used, such as spring steel, stainless steel or high strength zinc alloy.

Referring now to figures 1 and 4, the lock housing member 30 will be 20 described in detail. The housing 30 comprises a framework 31 in which the strip 11 is received through aperture 32 and in which the lock member is received in aperture 33. The framework 31 provides an arm 34 which restrains the reverse face 23 of the strip when it is engaged in the housing. The leading edge 35 of the restraining arm 34 (ie. the edge facing the direction of insertion of the leading edge 18 of the strip 11, indicated by arrow A) is preferably bevelled to guide the strip into the housing, allowing for any slight misalignment thereof.

7 The housing 30 is secured to the window sash 2 by suitable bolts or screws (not shown) through fixing holes 36 at the top and bottom of the housing. Preferably, the housing 30 partly resides in an industry standard sized groove 8 (figure 1) in the sash frame, which also carries an actuator drive rod mechanism to be described hereinafter.

Preferably, the housing 30 is formed from an appropriate material such as high strength zinc alloy, stainless steel, GRP or Kevlar".

Referring now to figures 1 and 5, the lock member 50 will now be described in detail. Lock member 50 comprises a plate 54 whose front surface defines an engagement surface 51 which includes a plurality of parallel ribs 52 extending across the front surface in similar manner to that described in relation to strip 11. The ribs comprise a series of teeth 60 of corresponding pitch to those of the strip 11. Preferably, therefore, the teeth 60 have a leading edge profile 61 which is preferably moderately inclined with respect to the plane of the engagement surface 51. In a preferred embodiment, the angle between the plane of the engagement surface 51 and the tooth leading edge 61 is approximately 0 40. The teeth 60 preferably have a trailing edge profile 62 which is perpendicular or near perpendicular to the plane of the engagement surface 51. In a preferred embodiment, the trailing edge profile is re entrant. In other words, the top comer of the tooth overhangs the edge of the base of the tooth, and preferably the angle between the trailing edge profile 62 and the plane of the engagement surface 51 is approximately 94', ie. 4' from orthogonal.

The teeth 60 each have a longitudinal axis which is transverse to the axis of the lock member 50 (ie. the lock member axis which extends between 8 a leading end 64 and a trailing end 65, in which the leading end is the first end to meet the strip I I when closing the window sash 2). In a preferred embodiment, the teeth 60 axes are slightly off-perpendicular to the lock member axis, and preferably approximately 6 off5 perpendicular as particularly shown in figure 5.

Preferably, the lock member 50 is formed from a high strength zinc alloy, stainless steel, GRP or Kevlar".

The lock member 50 ftirther includes a shaft 55 extending from the rear face of the plate 54 defining the engagement surface 51. Shaft 55 is adapted to pass through a hole in an actuator drive rod 70 (seen in crosssection in figure 1), being retained therein by suitable means such as swaging the shaft 55 over the drive rod 70, or providing a nut 56 at the end of the shaft 55. The actuator drive rod 70 extends longitudinally along the channel or groove 8 in the sash 2, according to well known mechanisms.

The width w, (figure 5a) of the lock member 50 is preferably approximately equal to, or slightly less than, half the width w, (figure 3a) of the strip 11, and the width w, of the engagement surface 14 of the strip is preferably approximately equal to the width wl. The width w, of the lock member is preferably also approximately equal to the width wd of the disengagement surface 15 of the strip 11.

The lock member 50 is able to slide, within the lock-receiving aperture 33 of the housing 30, under the control of the actuator drive rod 70, so that it opposes and makes contact with either the engagement surface 14 of the strip 11, or the disengagement surface 15 of the strip, or a part of 9 both. In figure 1, this movement will be understood to be into and out of the plane of the drawing.

In the preferred embodiment illustrated in figure 1, a small gap 72 is preferably provided between the rear face of the plate 54 and the actuator drive rod 70 to allow the lock member 50 a degree of freedom in a direction parallel to the axis of the shaft 56, ie. orthogonal to the plane of the engagement surfaces 51 and 14. Into this gap 72 is installed a leaf spring 80 as shown in figure 6. This leaf spring urges the engagement surface 51 of the lock member 50 into locking engagement with the engagement surface 14 of the strip 11, but enables the lock member 50 to ride up and over the inclined leading edges 21 of the teeth 20 when the lock member is sliding over the strip in one direction only.

With reference now to figures I and 7, the operation of the locking mechanism will now be described.

In an open condition of the window sash (as shown in figure 7a), the sash 2 and the window frame 1 and corresponding parts of the locking mechanism (ie. rack and lock members) are separated.

As the window is closed, the sash 2 is brought into position along side window frame 1, at which point the leading end 18 of the rack member 10 enters the aperture 32 of housing 30.

There are two modes of operation in the embodiment described above. The first of these is an "autolocking" mode, in which the engagement surface 51 of the lock member 50 is already in line with the engagement surface 14 of the strip 11 during the closing operation. The second 10 mode is a manual locking mode where the engagement surface 51 of the lock member 50 is not in line with the engagement surface 14, but fully, in line with the disengagement surface 15 of the strip 11 during the closing operation.

In the first mode, the leading edge of the first tooth 20 of the leading end 18 of the strip 11 collides with the lock member 50 which is biassed toward the restraining arm 34. However, the leading edge profile 21 of each tooth 20 forces the lock member to recede into the groove 8 against the bias of the leaf spring 80 in a ratchet-and-pawl type action, allowing strip 11 to pass through the housing 30, but only in the closing direction. The trailing edge profile 22 of the teeth 20 prevents reversal of this closing action. It will be understood that the closing action can be halted at any desired point, at which the window will be secured in a partly open, "ventilation" position (figure 7b). The fully closed position is shown in figure 7c and figure 1.

In the second mode, the window sash 2 is brought into the closure position while the lock member 50 is displaced along the channel 8 by the actuator drive rod 70, so that engagement surface 51 of the lock member 50 is in line with the disengagement surface 15 of the strip. In this case, the sash 2 can move freely in the opening and closing directions as the teeth 60 of the lock member pass easily over the disengagement surface 15 of the strip in either direction.

In the second mode, to secure the window in a fully closed or partially closed (ventilation) position (figures 7b and 7c), the actuator drive rod is used to drive the lock member longitudinally within the channel 8 (ie. into or out of the plane of the drawing), in the housing 30, until the 11 parallel sets of teeth 20 and 60 interlock with one another. In the preferred embodiment, in which the ribs 12 are pitched at, for example, 6' to the axis perpendicular to the closure direction "A" (figure 4), as the actuator drive rod 70 moves the lock member 50 to its engaged position, a further slight displacement of the sash frame occurs in the closure direction caused by the pitched ribs, thereby tightening the closure of the window. In the fully closed position, this serves to compress the seal in channel 5 (figure 1).

To re-open the window, the actuator drive rod 70 is deployed in the reverse direction to drive the lock member 50 so that it slides across the strip 11, off the engagement surface 14 and onto the disengagement surface 15. The window sash 2 is then free to open and close.

It will be understood that in the second mode of operation, the leaf spring 74 and gap 72 could, in fact, be omitted from the mechanism (making allowances for any required clearances), as a ratchet-and-pawl type closure operation is not required.

In this case, the inclined leading edge profile 21 of the teeth 20 is also not required. The teeth can then have any suitable profile.

With reference to figures 8 to 13, a modified rack member, according to one aspect of the present invention, is now described. In many circumstances, the rack member 10 and the lock housing member 30 may be for fitting to, for example, a window frame 1 and window sash 2 which may be less than perfectly installed or which may be subject to movement or distortion over time. This might occur as a result of 12 building movements, or other factors such as temperature changes, humidity changes, wear or mechanical damage etc.

It is therefore desirable that the lock mechanism is as tolerant as possible to consequent mis-registration or misalignment of the lock member 10 and the lock housing member 30. It will be understood that mis registration in a direction parallel to the rack member engagement surface 14 is readily accommodated by varying the dimension w, of the strip 11 relative to the receiving aperture 32 of the lock housing member.

Figure 8 shows an exploded perspective view of a modified rack member 110 which provides a self-adjusting function in the event that misregistration of the rack member and lock housing member 30 occurs in a direction out-of-plane of the rack member. The modified rack member 110 exemplifies a self-adjusting lock keep according to the present invention.

The rack member 110 comprises a strip I I I and fixing plate 117 which 20 are formed as separate parts. The strip 111 includes a distal or "leading" end 118 and a proximal or "trailing" end 119. The proximal end 119 includes a pair of pins 136, 137 which extend down from the reverse face 123 of the strip Ill and ride within respective sockets 138, 139 in the fixing plate 117.

An aperture 140 in the fixing plate 117 houses the lower end of a compression spring 141, the other end of which spring bears against the reverse face of the proximal end of strip I 11 to act as a bias means to maintain separation of the strip 111 and the fixing plate 117.

13 As best seen with reference to figures 9 to 11, in particular figure 9h, the rack member I 10 and fixing plate 117 are prevented from complete detachment from one another, under the spring bias, by washers 142 which are fixed to the remote ends of the pins 136, 137 after installation of the pins into sockets 138, 139. The peripheral edges of the washers 142 bear against respective shoulders 143 at the base of the sockets 138, 139, when the rack member 110 is at the top position as depicted in figures 9a to 9h.

The sidewaRs 144 of the apertures 138, 139, together with the pins 136, 138 together define an extendable support post 116 which is able to vary the separation distance between the strip I I I and a substrate upon which the fixing plate 117 is attached, whilst maintaining them substantially parallel to one another.

The extendable support post 116 enables the strip I 11 to move between a "top" position as shown in figure 9 in which the support post is fully extended, through a "midway" position (figure 10) in which the support post is half-extended, to a "bottom" position (figure 11) in which the support post is fully compressed.

In all other aspects of design, the rack member 110 may have identical structures, such as teeth 120, to the rack member 10 described earlier.

It will be understood that the modified rack member 110 thereby provides a degree of freedom to the alignment of strip I I I to the strip receiving aperture 32 of the lock housing member.

14 The rack member 110 can be formed from any suitable material, such as steel, stainless steel, copper and zinc alloys or, preferably synthetic materials such as polymers.

The locking mechanism as described above can readily be used in any orientation around a window casement, and is ideally suited for multipoint locking with each lock member 50 being driven by a common actuating mechanism linked through the actuator drive rod or a series of actuator drive rods linked around the window sash.

The mechanism is highly resistant to being forced or jemm-ied. Any attempt to bend the strip 11 toward the window frame 1 to attempt to disengage corresponding teeth 20, 60 is prevented in the preferred embodiment by the restraining arm 34 and by the action of the re-entrant trailing edge tooth profiles 22,62 which provide a further clamping force. Any attempt to distort the sash 2 to move the lock member 50 so as to prise it away from the strip 11 is defeated because the restraining arm 34 will pull the resilient strip 11 in the same direction as the distortion of the sash 2, preventing the teeth 20, 60 from disengaging.

Only movement substantially parallel to the ribs, in the correct direction of the actuator drive rod 70, will allow the teeth 20, 60 to disengage.

The length of the ribs, ie. approximately the width w, and w, can be made as long as required for a given degree of security. Slightly re- entrant teeth 20, 60 are preferred so that any attempt to force the window open merely results in tighter engagement of the engaged teeth. High locking strength is assured by a large total surface area of engaged teeth, ie. the cumulative trailing edges of all engaged teeth.

It will be understood that the locking mechanism described above is readily adaptable to lock together any first component bearing the rack member 10 and any second component bearing the lock member 50 and housing 30.

The window sash and frame could be reversed with respect to the members attached thereto. The first and second components need not be window and door components. The principle can be applied to, inter alia, reusable cable ties, luggage straps, child safety locks for cupboards, bicycle locks, car steering wheel locks, padlocks, other lock out devices, and reusable label tabs.

It will also be understood that features of the rack member and lock member are interchangeable in the sense that the disengagement surface 15 could be provided on the lock member 50 rather than on the rack member 10.

It will also be understood that multiple parallel engagement surfaces 14 separated by one or more disengagement surfaces 15 on the rack member 10 (with corresponding surfaces on the lock member 50) could be provided as alternating rows, each having a width w, and each adapted to engage with an appropriate portion of the lock member 50.

The locking mechanism herein described is highly resistant to being forced, as most forces which can be applied will generate opposing forces thereto. The operating forces required for normal opening and closing are, however, very low. The number of ventilation positions available is high, owing to the small pitch (spacing) of the teeth 20 and their extent is simply determined by the length of rack member 10. The 16 ratchet-and-pawl facility (optional) allows a partially opened window to be closed regardless of whether the operator possesses a key to the actuator drive mechanism, thereby offering greater security. All parts can be readily fabricated from a wide variety of corrosion resistant materials and the design allows for quick and easy assembly and full compatibility with known industry standard window sash and frame profiles.

More generally, the principle of the self-adjusting keep as described 10 above can be applied to many other types of lock mechanism, and in general to any lock mechanism in which a lock keep provides an engagement surface at a predetermined distance from a substrate such as the window frame and in which a second component provides for engagement with and around the lock keep.

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Claims (13)

1. I A self-adjusting lock keep comprising:

   a base for securing the lock keep to a first component; and an engagement surface maintained spaced apart from said base for being received by and for engaging with a lock member secured to a second component, along a closure axis substantially parallel with said engagement surface, the distance between the engagement surface and the base being automatically variable in a direction substantially orthogonal to the closure axis.
2. 2. A self-adjusting lock keep according to claim I including bias means to maintain the engagement surface at a predetermined spacing from the base when not otherwise displaced by a lock member.
3. 3. A self-adjusting lock keep according to claim I or claim 2 further including a support post between the engagement surface and the base, the support post being variable in length.
4. 4. A self-adjusting lock keep according to claim 3 in which the support post comprises at least one pin, substantially orthogonal to the engagement surface, which travels in a longitudinal direction within a corresponding socket attached to the base.
5. 5. A self-adjusting lock keep according to claim 1 or claim 2 wherein the engagement surface is defined by a strip or finger having a leading end and a trailing end, the leading end including means for engagement with a receiving means adapted to receive and engage with 18 the finger, the trailing end of the finger being coupled to, and spaced apart from, a fixing plate forming said base, by way of a support post which is variable in length.
6. 6. A self-adjusting lock keep according to claim 5 in which the leading end of the strip includes a bevelled end.
7. 7. A locking mechanism comprising:

   a rack member, for attachment to a first component, the rack member having an engagement surface including a first plurality of substantially parallel ribs extending along the surface in a first direction, a base for attachment of the rack member to the first component, and a support post between the engagement surface and the base, which support post is variable in length; a lock member, for attachment to a second component which is to be releasably secured to the first component by said locking mechanism, the lock member including an engagement surface having a second plurality of substantially parallel ribs adapted to engage with at least some of the first plurality of ribs on said first engagement surface; means for maintaining said engagement surfaces of said rack member and lock member in overlying relationship to lock together said first and second components; and means for disengaging said rack member and said lock member by providing relative movement of said rack member and lock member in a direction substantially parallel to said ribs until said first and second plurality of ribs disengage, so as to disengage said first and second components.

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8. 8. A locking mechanism according to claim 7 wherein said first and second components are adapted to separate and come together along a closure axis transverse to said first direction, the variable length of the support post enabling automatic alignment of the engagement surfaces of 5 the lock member and the rack member.
9. 9. A locking mechanism according to claim 8 wherein said closure axis is substantially orthogonal to said first direction.
10. 10. A locking mechanism according to claim 7 wherein said rack member or said lock member includes a disengagement surface, substantially coplanar with said engagement surface, which allows smooth travel of said corresponding lock or rack member thereover, the boundary between said engagement and disengagement surfaces being parallel to a closure axis of the first and second components, the plurality of ribs being transverse to said closure axis.
11. 11. A locking mechanism according to 7 in which said rack member comprises a strip having a front face bearing said engagement and disengagement surfaces, and a support portion at one end thereof for mounting onto a surface of said first component so as to hold the strip spaced apart from the surface of said first component.
12. 12. A locking mechanism according to claim 11 further including a housing for attachment to said second component, said housing defining an elongate aperture adapted to receive the cross-sectional profile of said strip and provide a restraining arm for a reverse face of said strip when said rack member and said lock member are in engaged positions.
13. 13. A self-adjusting lock keep substantially as described herein with reference to the accompanying drawings.

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