GB1600854A - Latches - Google Patents

Description

(54) IMPROVEMENTS RELATING TO LATCHES (71) We, HOWARD S. COOKE & COM PANY LIMITED, of Arrow Road, Redditch B98 sPA, Hereford and Worcestershire, a British Company, 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 This invention relates to latches particularly for securing the doors of motor vehicles.

The object of the invention is to provide simple and robust constructions particularly for use on commercial vehicle doors.

The invention provides a latch comprising a casing of two parts held together by fasteners at a plurality of points, in which ones of the fastenings provide pivotal mountings for a first or latch pawl, which is to engage or release from a keeper when the casing is mounted for example on the door and the keeper mounted on the door frame, for a second or locking pawl which is adapted to hold the first pawl in either of first or second engaged positions or allow movement of the latch pawl to a third and open position, and a release cam for displacing the second pawl clear of the latch pawl, at least the two pawls (and also possibly the cam) being individually spring urged.

The invention is now more particularly illustrated with reference to the accompanying drawings wherein: Fig. 1 is a perspective view showing the construction of latch with parts removed for clarity, Fig. 2 shows a first construction of keeper, Fig. 3 a second construction of keeper, for association with the latch (Fig. 1), Fig. 4 shows a modified latch construction with an operating and locking means therefor, Fig. 5 is an elevation of the latch shown in Fig. 4 showing an additional locking means, Fig. 6 shows the latch of Figs. 1 to 3 with an associated operating mechanism incorporating a lock, Fig. 7 is an enlarged fragmentary sectional elevation of the arrangement shown in Fig. 6, and, Fig. 8 is an exploded fragmentary perspective view of the part shown in Fig. 7.

Referring now to the drawings, a latch may comprise a pair of substantially (if not entirely) identical pressings of heavy gauge sheet metal, indicated by the reference numeral 10 and each being of shallow channel section, the two parts 10 being fitted together mouth to mouth to form a generally hollow box open at each end. Only the one part 10 is shown in the drawings.

Each of the parts 10 has generally parallel side walls 12 extending from one of the open ends, and converging side wall portions 14 adjacent the opposite open end. The side walls 14 are cut away at 16 so that blocks 18 (only one of which is shown in the drawing) having grooves 20 in their opposite sides, and which can conveniently be made of a nylon or like material (for the purpose hereinafter mentioned) can be inserted in the cut away portions so as to provide a pad of the nylon or like on the exterior.

The purpose of the blocks 18 is so that when the latch construction of Fig. 1 (with the second casing part 10 secured in position) is mounted for example on the vehicle door, and the door is closed, the tapering part can enter into guide portions of a keeper and the nylon or like pads can absorb impact especially but not only in the event that the parts are not precisely aligned, so as to bring the parts into proper alignement. A hard rubber or the like could be substituted for the nylon.

The two casing parts are held together by four rivets or tubular rivets 22, 24, 26, 28.

The rivet 22 mounts a first or latch pawl 30, for pivoting thereon. The rivet 24 mounts a locking pawl 32 for pivoting on that rivet, and the rivet 26 mounts a release cam 34 pivotally thereon. Each of the pawls 30, 32 and the cam 34 is individually spring urged by corresponding torsion spring wound about the corresponding rivet and having tails engaged respectively with the part 10 and with the part 30, 32 or 34 for example via the holes 36.

The latch pawl 30 includes ajaw 40 which in pivotal movement of the part swings across the mouth at the open end of the casing so as to trap a keeper part (which may be generally rod like) within the jaw. The latchpawl 30 also includes generally V shaped recesses 42, 44 and 46, which are angularly space about the axis of the rivet 22.

A locking pawl 32 includes a detent 48 complementary in shape to the V shaped recesses 42 to 46, and an abutment shoulder 50.

The edge of the locking pawl 30 as indicated generally by the reference numeral 52 is arranged so that if the latch pawl is in the completely free position, with the detent 48 engaged in recess 46, and the door carrying the latch is slammed shut, the rod like part of the keeper will hit that surface and turn the pawl anit-clockwise (in the illustration) pivoting the locking pawl 32 clockwise (in the illustration) and the spring loading will then tend to take the pawl 30 towards the illustrated position and the pawl 32 to the position where detent 48 engages recess 42. The pawl may however stop in the position where the detent engages recess 44, but in either case the keeper will be trapped within the jaw 40.

The release cam 34 is displaced in the direction of the arrow 54 so as to pivot anticlockwise about its mounting pin or rivet, and then heel 56 on the cam will displace the abutment 50 on the locking pawl to disengage the detent from any engaged recess and permit the pawl 30 to pivot clockwise (in the illustration) so as to disengage the keeper from the jaw. The spring loading on the parts will return the detent as soon as the force displacing the cam 34 is released and in general this will be whilst the limb 58 is pivoting about the keeper, so that the pawl 30 is held in the clockwise displaced position from the illustrated position so that the detent 48 will tend to re-engage with the recess 46, thus holding the latch parts in the position for reengagement when the door is again closed.

Fig. 2 of the drawings shows a keeper which may be for use where the door carrying the latch is a sliding door, faces 60 to 62 being being provided for engagement by the converging ends 14 of the side walls of the latch casing, and by the pads 18 carried thereby, and rod 64 being provided for engagement by the jaw 40.

Fig. 3 shows an alternative keeper where the rods 66, 68 correspond to the faces 60, 62 of the Fig. 2 construction and the rod 70 corresponds to the rod 64. This may be for use where the door carrying the latch is hinged. Both of the striker plates of Figs. 2 and 3 are provided with slots 72 for securing bolts enabling the positions of the keepers to be adjusted.

In the modified construction of Fig. 4, the latch is generally similar to that described with reference to Fig. 1, but the release cam 34 is replaced by a release cam 134 which cooperates with the abutment 50 on the locking pawl 30 in generally the same say as in the case of Fig. 1. However, the release cam 134 includes a portion 136 which extends through an aperture in the casing so as to mount operating handle 138. The locking pawl is therefore released by appropriate pivotal movement of the pawl 134.

In order to provide for locking, a snib lock 140 is pivoted at 142 on the extension 136 for movement between the full line and a dotted line position shown in Fig. 4. The aperture in the latch casing allows the snib to enter (when the snib is in the full line position) and this prevents the pivotal movement necessary for latch release. The snib can be swung to the dotted line position to allow latch release. It will be appreciated that the snib may be moved by a control button or lever from a remote position on the door.

Additionally, the release cam 134 is provided with a transversely extending peg 144 which operates in slots 146 in the casing parts, and the part 144 can be extended to project to either side of the latch casing as indicated by the full line and broken line respectively in Fig. 5. Since the part 144 is to move with the release cam 134, the part 144 can be blocked by a lockable mechanism to prevent the opening of the door, that is prevent release of the latch, and one typical arangement for this purpose is illustrated in Fig. 5, wherein a key (148) operated lock 150 has an angularly movable part 152 which can be swung into and out of the path of the part 144 according to requirements.

Turning now to Fig. 6, the latch shown therein is generally similar to that in Fig. 1, but the cam 34 is attached, for example by riveting, to an L-shaped operating lever 234 which is pivoted at 236 on an extension 238 provided as part of an assembly mounted on the door with the latch and adjacent thereto.

The L-shaped part 234 has a slot 240 in its free end which receives an operating pin 242 carried by a second and generally transversely located L-shaped part 244. The other end of the part 244 is fixed to a bolt 246. Axial movement of the bolt 246 pivots the L-shaped part 234 and displaces the cam 34 for release.

As best seen in Figure 7, the head of the bolt 246 clamps the part 244 against the lock nut 248, and with an interposed washer 250 against the end of a stem 252. The latter is coupled to the barrel 254 of the lock, and the lock is slidable but non-rotatable through the assembly of handle 256 and door skin 258, as also seen in Fig. 8. The lock barrel carries a washer 260 which is rotatable with the key turned part of the lock and the washer 260 has a projecting lug 262. Located within the door and between the skin 258 and the second skin 264 is a pair of generally U-shaped brackets 266, 268, and these have appropriate apertures 270 and 272 respectively so that stem 252 is held against the bracket 268 by the bolt and washer assembly, and a helical compression springs 272 acts between bracket 268 and the washer 260. The effect of the spring is to hold the washer 260 in the position illustrated in Fig. 7, but in the event that the lock is key operated to turn the washer 260 to align into the complementary aperture 270, the lock can be pushed inwardly, that is in the direction of the arrow A, Figure 7, to take the asher through that aperture, and this will displace the stem 252 and the bolt 246 to cause the pivoting movement of the L-shaped part and latch operation.

WHAT WE CLAIM IS:- 1. A latch comprising a casing of two parts held together by fasteners at a plurality of points, in which ones of the fastenings provide pivotal mountings for a first or latch pawl, which is to engage or release from a keeper when the casing is mounted for example on the door and the keeper mounted on the door frame, for a second or locking pawl which is adapted to hold the first pawl in either of first or second engaged positions or allow movement of the latch pawl to a third and open position, and a release cam for displacing the second pawl clear of the latch pawl, at least the two pawls being individually spring urged.

2. A latch as claimed in Claim 1 wherein the two parts provide a generally hollow box like shape which is open on parallel sides, and the latch pawl is adapted to engage with a keeper in the vicinity of one of said sides, whereas the release cam is located in the vicinity of the other of said sides for operation therethrough.

3. A latch as claimed in claim 1 or Claim 2 wherein means are provided for displacing the release cam by movement in a direction parallel to the pivotal axis of said cam.

4. A latch as claimed in Claim 1 wherein the release cam has an extension projecting through a wall of the casing for connection to an operating handle or lever for effecting release of the latch.

5. A latch as claimed in Claim 4 wherein a snib is pivoted on said extension for engagement between the same and the wall of the aperture in the casing for the purpose of preventing said release.

6. A latch as claimed in claim 1 in which said cam is also individually spring-urged.

7. A latch as claimed in Claim 4 wherein the relase cam is provided with a projection parallel to the pivotal axis of the release cam extending through the elongated slot in the casing for cooperation with a key operated lock.

8. A latch substantially as described with reference to Figure 1, or to Figures 1 and 2, or to Figures 1 and 3, or to Figures 4 and 5, or to Figure 1 and Figures 6 to 8 of the accompanying drawings.

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

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. in Fig. 7, but in the event that the lock is key operated to turn the washer 260 to align into the complementary aperture 270, the lock can be pushed inwardly, that is in the direction of the arrow A, Figure 7, to take the asher through that aperture, and this will displace the stem 252 and the bolt 246 to cause the pivoting movement of the L-shaped part and latch operation. WHAT WE CLAIM IS:-

1. A latch comprising a casing of two parts held together by fasteners at a plurality of points, in which ones of the fastenings provide pivotal mountings for a first or latch pawl, which is to engage or release from a keeper when the casing is mounted for example on the door and the keeper mounted on the door frame, for a second or locking pawl which is adapted to hold the first pawl in either of first or second engaged positions or allow movement of the latch pawl to a third and open position, and a release cam for displacing the second pawl clear of the latch pawl, at least the two pawls being individually spring urged.

2. A latch as claimed in Claim 1 wherein the two parts provide a generally hollow box like shape which is open on parallel sides, and the latch pawl is adapted to engage with a keeper in the vicinity of one of said sides, whereas the release cam is located in the vicinity of the other of said sides for operation therethrough.

3. A latch as claimed in claim 1 or Claim 2 wherein means are provided for displacing the release cam by movement in a direction parallel to the pivotal axis of said cam.

4. A latch as claimed in Claim 1 wherein the release cam has an extension projecting through a wall of the casing for connection to an operating handle or lever for effecting release of the latch.

5. A latch as claimed in Claim 4 wherein a snib is pivoted on said extension for engagement between the same and the wall of the aperture in the casing for the purpose of preventing said release.

6. A latch as claimed in claim 1 in which said cam is also individually spring-urged.

7. A latch as claimed in Claim 4 wherein the relase cam is provided with a projection parallel to the pivotal axis of the release cam extending through the elongated slot in the casing for cooperation with a key operated lock.

8. A latch substantially as described with reference to Figure 1, or to Figures 1 and 2, or to Figures 1 and 3, or to Figures 4 and 5, or to Figure 1 and Figures 6 to 8 of the accompanying drawings.