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Patent Searching and Data


Title:
LATCH MECHANISM
Document Type and Number:
WIPO Patent Application WO/1988/007616
Kind Code:
A1
Abstract:
A latch mechanism (2) for a door (4) comprising a casing (14) having a bolt assembly (38) reciprocally mounted therein, a spring (60) for biasing the assembly (38) to an extended latching position, an operating shaft (66) extends traversely to the assembly (38) and includes a V-shaped notch (68). The bolt assembly (38) includes a roller (52) which is located in the notch (68). The shaft (66) is capable of push-pull movement and/or rotational movement and, on any of these movements, the notch (68) engages the roller (52) and causes the bolt assembly (38) to move to its retracted position.

Inventors:
ALTHAUS WILLI ALBRECHT (AU)
ALTHAUS MARIE RUTH (AU)
Application Number:
PCT/AU1988/000089
Publication Date:
October 06, 1988
Filing Date:
March 30, 1988
Export Citation:
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Assignee:
ALTHAUS WILLI ALBRECHT (AU)
ALTHAUS MARIE RUTH (AU)
International Classes:
E05C1/14; E05B17/00; (IPC1-7): E05C1/14; E05C1/06; E05C1/08; E05C1/12
Foreign References:
US3582121A1971-06-01
US3490803A1970-01-20
FR1558519A1969-02-28
DE2351807A11975-04-24
US2517378A1950-08-01
US2507289A1950-05-09
US2504483A1950-04-18
US3494650A1970-02-10
US2747907A1956-05-29
AU372039A
US2383574A1945-08-28
US3385622A1968-05-28
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Claims:
CLAIMS
1. A latch mechanism (12) comprising a casing (14) having a bolt member (12) reciprocally mounted therein, a biasing means (60) for biasing the bolt member (12) to an extended latching position, an operating member (66) which, in use moves the bolt to a retracted position characterised in that the operating member (66) is mounted for pushpull and rotational movement and wherein a pushpull and/or rotational movement thereof is effective to move the bolt member to its retracted position.
2. A mechanism as claimed in claim 1 wherein the operating member (66) comprises an operating shaft (66) which is provided with first cam means (72, 74, 124, 126) which copperate with second cam means (52) coupled to the bolt member (12), the arrangement being such that on pushpull or rotational movement of the operating shaft the first and second can means engage and cause the bolt member to move to its retracted position.
3. A mechanism as claimed in claim 2 wherein the bolt member (12) is located at one end of a bolt assembly (38) which is constrained for sliding movement in the casing (14).
4. A mechanism as claimed in claim 3 wherein the assembly (38) includes a support member (38) which has rollers (48,50) mounted thereon for engagement with the casing (14) to facilitate sliding movement of the assembly (38) within the casing (14).
5. A mechanism as claimed in claimed in any one of claims 3 or 4 wherein the first cam means includes first and second cam surfaces (70,72) formed into the operating shaft (66) .
6. A mechanism as claimed in claim 5 wherein the second cam means comprises an operating roller (52) mounted in said bolt assembly (38) and engageable by said cam surfaces (70,72).
7. A mechanism as claimed in claim 6 wherein said cam surfaces (70,72) define a notch (68) in said operating shaft (66) and wherein, on rotation of the shaft, top or bottom portions (124, 126) of the notch (68) come into engagement with the operating roller (52) and thereby cause retraction of the bolt assembly (38) . .
8. A mechanism as claimed in any one of claims 3 to 5 wherein the biasing means comprises a compression spring (60) located in the assembly (38) and acting between first and second abutment means (58,62) provided on the assembly (38) and casing (14) respectively.
9. A mechanism as claimed in any one of claims 2 to 8 including a knob assembly (76) mounted on one or both ends of the operating shaft (66).
10. A mechanism as claimed in claim 9 wherein the knob assembly (76) includes a bush (82) one end (86) of which registers with the casing (14), and wherein the operating shaft (66) passes through the bush (82) .
11. A mechanism as claimed in claim 10 wherein the knob assembly (26) includes a mounting plate (78) having a threaded bore (80) which receives a threaded end (84) of the bush (82).
12. A mechanism as claimed in any one of claims 10 or 11 wherein the knob assembly (76) includes a knob body (94) which is nonrotatably mounted on the end of the operating shaft (66), the knob body (94) 13 being arranged .to transmit rotational or pushpull forces applied thereto to the shaft (66).
13. A mechanism as claimed in claim 12 including a second compression spring (110) which acts between the bush (82) and the knob body (94).
14. A mechanism as claimed in claim 13 wherein the second compression spring (110) serves to return the knob body (94) to predetermined rotational and axial positions relative to the bush (82) .
15. A mechanism as claimed in claim 14 wherein the ends of the second compression spring (110) are formed with legs (114, 116) which are captively received within openings (118, 92) formed in the shaft (66) and bush (82) respectively.
16. A mechanism as claimed in any one of claims 12 to 15 wherein the knob assembly (76) includes a first cam member (96) which projects inwardly from the knob body (94) and cooperates with a second cam member (90) formed on the bush (82).
17. A mechanism as claimed in claim 16 wherein the first and second cam members (96,90) engage one another to limit rotational movement of the knob body (94) relative to the bush (82).
18. A mechanism as claimed in claim 17 wherein the first and second cam members (96,90) are shaped to limit said rotational movement in accordance to the axial position of the shaft (66) relative to the bush (82) .
19. A mechanism as claimed in claim 18 wherein the first cam member (96) comprises part of an annular wall with a curved outer face and defines an apex (128), and wherein the second cam member (90) comprises a curved recess formed in an annular wall of the bush (82) .
20. A mechanism as claimed in any one of claims 3 to 19 including a locking bolt (170) which can be operated to prevent sliding movement of the bolt assembly (38) .
21. A mechanism as claimed in claim 20 wherein the locking bolt (170) includes a locking shaft (172) which passes through a keyhole slot (56) formed in said bolt assembly (38), the locking shaft (172) including flats (176) which when aligned with an elongate portion of the slot (56) permit transverse movement of the bolt assembly (38) relative to the locking shaft.
Description:
LATCH MECHANISM

This invention relates to a latch mechanism for a door.

It is known to have latch mechanisms which operate by means of rotational movements in order to open or close the door. These mechanisms are normally satisfactory however they can present a problem for handicapped persons and children who may find such mechansims difficult to operate.

It is also known to provide latch mechanisms which can operate by means of either a push or pull movement in order to open or close the door. These arrangements do have the advantage that they can be more easily operated by children and handicapped persons but, generally speaking, they may be some what inconvenient for normal use because normally it is expected that the mechanism will be operated by means of a purely rotational movement.

It is the object of the present invention t° provide a novel form of latch mechanism which is capable of being operated by means of a push-pull movement as well as a rotational movement.

According to the present invention there is provided a latch mechanism (2) comprising a casing (14) having a bolt member (12) reciprocally mounted therein, biasing means (60) for biasing the bolt member (12) to an extended latching position, an operating member (66) which, in use, moves the bolt to a retracted position characterised in that the operating member (66) is mounted for push-pull and rotational movement and wherein a push-pull and/or rotational movement thereof is effective to move the bolt member to its retracted position.

The invention will now be further described with reference to the accompanying drawings, in which:

Figure 1 is a cross-sectional view through a latch mechanism constructed in accordance with the invention;

Figure 2 is a longitudinal cross-section along the line 2-2;

Figure 3 is a transverse cross-section along the line 3-3;

Figure* 4 is a transverse cross-section along the line 4-4 ;

Figure 5 is a fragmentry exploded view of the mechanism;

Figure 6 shows the innerface of the knob body;

Figure 7 shows the operating shaft;

Figure 8 shows one form of latch plate;

Figure 9 is a cross-section along the line 9-9;

Figure 10 is a fragmentry view of a bolt profile suitable for use with the latch plate of Figure 8;

Figure 11 shows another form of latch plate; Figure 12 is a cross-sectional view along the line 12-12;

Figure 13 is a fragmentry view of a bolt profile suitable for use with the latch plate of Figure 11;

Figure 14 is a view of a further form of latch plate;

Figure 15 is a sectional view along the line 15-15; and

Figure 16 is a fragmentry view of a bolt suitable for use with the latch plate of Figure 14.

The latch mechanism 2 illustrated in Figures 1 to 7 is for use with a door 4 which is hinged for movement in a frame 6. The door abuts a stop 8 in the usual manner. The frame 6 is provided with a latch plate 10 having a recess 11 for receipt of of a bolt 12.

The mechanism 2 includes an elongated casing 14 which has spaced sidewalls 16 and 18 and top and bottom walls 20 and 22. One end of the casing 14 includes an end plate 24 having an opening 26 through which the bolt 12 passes. The plate 24 includes screw holes 28 for mounting the end plate in an edge face 30 of the door, as seen in Figure 1. As best seen in Figures 3 and 4, the casing 14 is generally rectangular in cross-section but has inwardly directed shoulder portions 32, at the corners between the side faces and top and bottom faces. The sidewalls 16 and 18 include circular openings 34 and 36, as best seen in Figures 4 and 5.

The bolt 12 forms part of a slideable bolt assembly 38 which includes a support member 40 which has a sidewall 42 and top and bottom walls 44 and 46. The assembly 38 includes guide rollers 48 and 50 which are wider than the top and bottom walls 40 and 46, the sidewall 42 being provided with openings to permit the rollers to pass therethrough. As seen in Figures 3 and 4, the guide rollers 48 and 50 engage the inner surfaces of the sidewalls 16 and 18 of the casing 14. The shoulders 32 engage the end faces of the rollers and constrain the assembly 38 to linear motion within the casing 14. The rollers 48 and 50 may be formed from low friction plastics material.

The assembly 38 further includes an operating roller 42 which is of narrower diameter than the guide rollers 48 and 50, as best seen in Figure 4. The sidewall 46 includes a broad slot 54 and a keyhole slot 56. The assembly also has a partition 58 which extends generally between the top and bottom walls 44 and 46. The partition 58 could be formed intergally when the slots 54 and 56 are formed.

The assembly 38 further includes a compression spring 60 (see Figures 1 and 2) which acts against the partition 58 and a partition 62 which projects inwardly from the sidewall 16 of the casing 14. The partitions 58 and 62 may include locating tabs 64 which hold the spring 60 centrally within the support member 40. The spring 60 resilantly biases the assembly 38 such that the bolt 12 will tend to project through the end plate 24, as seen in Figures 1 and 2.

The mechanism 2 includes an operating shaft 66 which extends transversely relative to the casing

14. The shaft 66 includes a generally V-shaped recess 68 having cam faces 70 and 72 which each form angles of about 45° relative to the axis of the shaft, as best seen in Figure 7. The shaft 66 passes through the openings 34 and 36 of the casing and through the broad slot 54 of the member 40. The operating roller 52 is located generally within the recess 68, as seen in Figures 1 and 7.

When the mechanism is manufactured, the assembly 38 is normally captive in the casing 14 and cannot be removed therefrom. The mechanism is mounted in the door by first mounting the casing 14 and then drilling holes 74 through the door in order to align with the openings 34 and 36. The shaft 66 can then be inserted through the holes 74 and openings 34 and 36 by holding the bolt assembly 38 in its retracted position so that the ends of the shaft 66 can clear the roller 52 and pass through the broad slot 54. On release of the bolt assembly 38, the shaft 66 will be held in its operative position, as shown in Figure 1.

The mechanism includes knob assemblies 76 for moving the shaft 66, the knob assembly 76 being located at one or both ends of the shaft 66. In the arrangement illustrated in Figure 1, the knob assembly 76 includes a mounting plate 78 which is fixed to the face of the door by means of screws or the like (not shown) . The plate 78 includes a threaded bore 80. The assembly 76 includes a stepped bush 82 which has a threaded spigot portion 84 which is threaded through the recess 80 of the mounting plate 78. The inner end of the spigot portion 84 has a rebate 86 which engages the periphery of the opening 34 or 36 so as to assist in correctly

locating the bush 82 relative to the casing 14. The plate 78 is normally flush with the face of the door 4 and because the plate 78 is threadably mounted on the bush 82, the mechanism can be fitted to doors of differing thicknesses. The bush 82 has a wider portion 88, the end surface of which includes a generally V-shaped cam surface 90 which has a slot 92 located near its apex.

The assembly 76 includes a knob body 94 which has a projecting cam member 96 which is of generally complementry shape to the cam surface 90, as seen in Figure 6. The body 94 has a D-profile bore 98 therethrough for receipt of the end of the operating shaft * 66 which has a flat 100 and is of complementry shape to the bore 98. The body 94 is held on the end of the shaft by means of a nut 102 which threaded onto a stud 104 which projects from the end of the shaft 66. Thus, the knob body 94 and shaft 66 are constrained to rotate in unison. The assembly 76 includes a cover 106 which is snap fit or screwed into a recess 108 formed in the body 94 as shown in Figure 1.

The assembly 76 includes a compression spring 110 which surrounds the shaft 66, one end of the sring 110 is located within the wider portion 88 of the sleeve 82, the other end being located generally within the hollow interior 112 of the cam surface 96. In order to prevent unwanted rotation of the spring 110, its ends are formed with legs 114 and 116 which are received in the slot 92 and a hole 118 formed in the flat 100. The spring 110 operates to return the cam member 96 to the position in which its apex 128 is aligned with the slot 92 at the apex of the cam surface 90, as shown in Figure 1. The spring

also resiliently biases the knob assembly 76 away from the mounting plate 78.

In the arrangement shown in Figure 1, the assembly 76 includes sleeves 120 and 122 which are mounted on the plate 78 and knob body 94 respectively. The sleeve 120 is telescopely received in the sleeve 122 so as to conceal the components therein and provide a neat appearance for the mechanism. The sleeves could be formed from sheet metal. Alternatively they could be integrally moulded with the plate 78," bush 82 or the knob body 94. The length of the sleeves 120 and 122 is chosen so that they overlap for a range of possible door thicknesses.

The knob assembly 76 can be duplicated on the other side of the door or alternatively one or both of the assemblies may include handles or operating bars (not shown) .

The mechanism operates as follows. If the knob body 94 is pressed inwardly, the cam surface 70 engages the roller 52 and this causes inward retraction of the bolt assembly 38 against the action of the spring 60. Inward movement is limited by the cam member 96 engaging the bush 82. Thus the bolt 12 will clear the latch plate 10 and permit the door 4 to be opened. It will be appreciated that the direction of force applied to the knob body 94 is the same as that which is used to open the door 4 and hence this makes the door very easily operated by handicapped persons. In addition, the door can be used in safety applications where panic bars and the like are provided.

If on the other hand the knob body 94 is pulled, the cam surface 72 will engage the roller 52

and again cause inwardly retraction of the bolt assembly 38 to permit the door to be opened. A corresponding effect is achieved by operation of the knob body (not shown) on the other side of the door. Thus, the bolt 12 is retracted by means of push-pull movements. The action of the two springs 60 and 110 will tend to return the bolt assembly 38 and shaft 66 to the position shown in Figure 1 on release of the knob body 94.

If the knob body 96 is rotated from its position shown in Figure 1, the shaft 66 will be rotated therewith and the upper or lower apex regions 124 and 126 will come into engagement with the roller 52 and in either case will cause retraction of the bolt assembly 38. More particularly, when the knob body 94 is rotated clockwise, as shown in Figure 1, the top apex portion 124 will engage the roller 52. When it is rotated anticlockwise, the lower apex region 126 will engage the roller 52. The knob body 94 is permitted to rotate through about 90° which is sufficient for retraction of the bolt 12. Rotation is stopped by the apex 128 of the cam surface 96 coming into contact with the cam surface 90. If the knob body 94 is partially depressed and rotated, the apex 128 will engage the surface 90 earlier so as to restrict the amount of rotation possible when the knob body 94 has been partially pressed inwardly relative to the sleeve 82. The same effect will occur if the knob body 94 is first partly rotated then pressed. If the knob body 94 is fully depressed, the engagement of the cam 96 and surface 90 will prevent any rotation of the knob body 94 relative to the sleeve 82.

The latch mechanism may include a privacy

bolt 170 which is accessible from one side of the door 4 and, when operated, prevents the door from being opened from the other side. In the illustrated arrangement, the privacy bolt comprises a shaft 172 which is mounted for rotation in a bush 174 which extends through the door and is seated in an opening 176 in the sidewall 18 of the casing 14. The shaft 172 is the same diameter as the larger diameter portion of the keyhole slot 56 formed in the sidewall 42 of the member 40 and in use passes therethrough. The shaft 172 includes a pair of flats 176 which have approximately the same thickness as the width of the elongate portion of the keyhole slot 56. When the bolt 170 is rotated so that the flats 176 are aligned with the elongate portion of the slot 56, the bolt assembly 38 is free to move within the casing 14. When however the bolt 170 is rotated through 90° so that the flats 176 are transverse relative to the elongate part of the slot 56, sliding movement of the bolt assembly 38 is restrained. The end of the shaft 172 includes a spigot 178 which is received within a hole 180 in the sidewall 16 of the casing 14 and forms a bearing therewith.

Figure 8 shows an alternative form of latch plate 140 for use with mechanism of the invention. The latch plate 140 includes a pair of rollers 142 and 144 mounted on a pin 146. The plate includes a tongue member 148 formed intergally therewith and extending between the rollers. The tongue member 148 serves as a bridge to prevent the tip of the bolt 12 entering the gap between the rollers 142 and 144 and the adjacent edge of the latch plate 140. The rollers 142 and 144 reduce frictional engagement between the bolt 12 and the plate 140 and thus make

its operation relatively free and smooth. Figure 10 shows a plan view of the bolt 12 having a flat trailing face 158. This profile is suitable for operation with the plate 140.

Figure 11 shows a modified form of latch plate 152. In this arrangement, a single roller 154 is provided and the tongue 148 is omitted. Figure 13 shows a plan view of a suitable form of bolt profile for use with the latch plate 152. In this arrangement, the trailing face of the bolt 12 has an oblique face 156 which resists the tendency for the tip of the bolt to enter the space between the roller 154 and the plate 152.

Figure 14 shows a further form of latch plate 158 which has a block 160 of resiliant material located near the leading edge of its recess. The trailing edge 162 of the block 160 is rounded so as to avoid catching with the tip of the bolt 12. The preferred form of bolt profile for use with the plate 158 is shown in Figure 15. In this arrangement, the leading and trailing faces 164 and 166 are rounded.

Many modifications will be apparent to those skilled in the art without departing from the spirit and scope of the invention. For instance the provisional specifications accompanying Australian Patent applicaltion Nos. PI11192/87 and PI12087/87 disclose various modified arrangements and these are incorporated herein by cross-reference.