US3208785A - Door latches - Google Patents

Description

Sept. 28, 1965 M. J. JAMES 3,208,785

DOOR LATCHES Filed May 14, 1962 2 Sheets-Sheet 1 pr'l' r" 22 /OI/ J/O 24 2o 4 6 9 l? /2 l l L 36 INVENTOR AT TORNEY Sept. 28, 1965 M. J. JAMES 3,208,785

DOOR LATCHES Filed May 14, 1962 2 Sheets-Sheet 2 INvEN-rok ATTORNEY United States Patent 3,208,785 DOOR LATCHES Michael Joseph James, Charlton Kings, Cheltenham, England, assigner to Micro and Precision Monldings (Cheltenham), Limited, Cheltenham, England Filed May 14, 1962, Ser. No. 195,044 Claims priority, application Great Britain, May 16, 1961, 17,714/ 61 12 Claims. (Cl. 292-337) This .invention relates to door latches of the type having a generally tubular housing in which a slam bol-t is slidably mounted, and which can be released by door handles respectively mounted on opposite sides of the door and interconnected by an operating shaft.

The tubular housings of door latches of this type are normally split throughout the full length of the housing, apart from an outer ilanged portion which is used for attachment to the door. The two halves are normally of metal construction, the flange being attached to one halt and the other halt riveted to or slotted into the ange at one end and tixed to the other half by a diametrically arranged screw or rivet. It is necessary for the housing to be split to enable an internal releasing element or elements controlled by the shaft to be assembled within the housing, and the object of the invention is to provide a latch of the aforesaid type with a housing which is readily formed by moulding and can be assembled in a simple manner without the use of rivets, screws or the like According to the invention a door latch of the slambolt type has a generally tubular housing of moulded form which is split over an inner end section of the housing to form a split portion extending over substantially the whole length of the housing and a shorter split portion with an outer end which engages in a lip-like manner within the longer split portion, the portions being detachably secured together at the inner end of the housing.

The housing is conveniently moulded from a synthetic plastic material7 although die-casting of a suitable metal may be used and for the purposes of this speciiication is to be considered as moulding Preferably the portions are secured together by a yokelike spring clip with arms iixed to one of the portions and resiliently gripping the other portion. When a moulding of a suiiiciently resilient material is used the arms of the clip may be moulded integrally with one portion, conveniently the shorter portion. Alternatively, the housing may have an inner end section of circular form and reduced diameter on which tits a sleeve securing the portions together.

The housing is conveniently split rearwardly of the latch spring of the slam bolt, and the lip of the shorter split portion may form part of the inner spring abutment. A releasing element of generally tubular form may be pivotally mounted in both split portions, this element having a through aperture for the operating shaft and a projecting ear or the like which engages the slam bolt to effect release of the latch. The element is inserted in a bearing in the longer split portion before the shorter split portion is itted thereto, and such tting conveniently serves t0 locate the element in position within the housing.

The invention will now be further described with reference to the accompanying drawings which illustrate, by way of example, two door latches of the slam-bolt type in accordance with the invention, and in which:

FIGURE l is an inner end view of one latch,

FIGURE 2 is a sectional view on the line II-II in FIGURE 1,

FIGURE 3 is a sectional view on the line III- III in FIGURE 2,

FIGURE FIGURE 3,

4 is a sectional view on the line IV-IV in "ice FIGURE 5 is a sectional view on the line V-V in FIGURE 3,

FIGURE 6 is a detail view,

FIGURE 7 is a sectional view on the line in FIGURE 6,

FIGURE 8 is a further detail view,

FIGURE 9 is a sectional view on the line IX-IX in FIGURE 8, and

FIGURE 10 is a view similar to that of FIGURE 2 but of the other latch.

In each case the latch has a generally tubular housing 1 arranged for tting in a mortice bore 2 in the edge of a door 3, and at the outer end the body 1 has an integral ilange 4 with holes for xing screws 5.

At the outer end the housing 1 has an unsplit section, extending over the length A in FIGURES 2 and l0, and inwardly of that section the housing 1 is longitudinally split in an axial plane (B-B in FIGURES 1 and l0) t0 provide longer and shorter split housing portions 6 and 7 respectively. The longer split portion 6 extends the full length of the housing 1 and includes the tixing tlange 4. Over most of its length, apart from a short cylindrical inner end section 8, the housing 1 is of truncated circular shape in lateral cross-section With concentric arcuate upper and lower edges and straight parallel side edges, as clearly shown in the sectional views of FIGURES 4 and 5. Over the unsplit section the truncated shape of the housing 1 is reinforced by longitudinally extending side ribs 9.

A slam bolt 10 with the usual bevelled outer end 12 is mounted in a central guideway 13 in the longer split portion 6, and the bolt 10 projects from the housing 1 and is urged to the lat-ching position by a latch spring 14 within the housing 1. Both the guideway 13 and the bolt 10 are of the same, though smaller, general cross-sectional shape as the housing 1 so that the bolt is angularly located about the bolt axis within the housing.

The split portions 6 and 7 of the one latch are shown in greater detail in FIGURES 6 to 9, and in each case the shorter portion 7 has at the outer end a projecting lip 15 which engages within the guideway 13 (as shown clearly in FIGURE 2) to hold the split portions 6 and 7 together in the radial sense at the forward end of the split. The lip 15 of the latch shown in FIGURE 2 projects laterally outwardly and engages a step 16 in the portion 6 so that the lip 15 also locates the two portions 6 and 7 in the axial sense. In the latch of FIGURE l0 the corresponding lip 15 of the shorter portion 7 merely projects in the longitudinal direction and hence only provides relative radial location of the portions 6 and 7, axial location being achieved `in a manner described hereinat-ter.

The inner ends of the portions 6 and 7 are detachably secured together to complete the housing. In the latch of FIGURES l to 9 such securing is achieved by a yokelike spring clip 17 formed integrally with the shorter split portion 7 which is moulded from a synthetic plastic material, such as nylon, providing the necessary rigidity for the housing 1 as a whole and sufhcient iiexibility and resilience for the spring clip 17. The arms 17a of the clip 17 are moulded integrally with the portion 7 and embrace the cylindrical inner end section 8 of the housing 1 to secure the portions 6 and 7 together.

In the latch of FIGURE l0 the plane B-B contains the central bolt axis and the inner end section 8 of the housing 1 is accordingly split diametrically into two semicircular sections respectively formed on the portions 6 and 7. In this case the portions 6 and 7 are nally secured together by a cylindrical sleeve 18 which is fitted longitudinally over the end section 8 when the portions 6 and 7 are tted together. The sleeve 18 is a light push iit on the section 8 so that the latch can easily be assembled by hand, and it is conveniently also moulded from VII-VII a es a synthetic plastic material such as nylon. In fact, all the components of the described latches, other than the l latch springs 14, are conveniently moulded from such a synthetic plastic material.

The outer edges of the spring arms 17a lie Within the diameter of the upper and lower arcuate edges of the main length of the housing 1, that diameter being greater than the outer diameter of the sleeve 13. Thus the securing means, formed either by the spring clip 17 or the sleeve 18, do not impede fitting of the latch in the mortice bore 2.

In both the illustrated latches the lip 15 on the split portion 7 forms part of an inner abutment for the latch spring 1li; the remainder of the abutment, which is of annular form, is provided by a shoulder 19 formed in the bore 13 of the split portion 6. A releasing element 20 of generally tubular form is rotatably mounted in aligned radial bearing bores 22 and 23 formed respectively in the split portions 6 and 7. The element 20 has a through aperture 24 of square cross-section for engagement by a squared operating shaft 25 which in use Couples the element 20 to inner and outer door handles 26 and 27. In FIGURE lO the handles 26 and 27 are not illustrated and the shaft 25 is partially cut away, and these parts can be considered as identical with those shown in the preceding figures. Locking means 28, which form no part of the invention and hence will not be described in detail, enable the latch to be locked from inside the door so that it cannot be released by means of the external door handle 27.

The element 20 has two mutually divergent radially projecting ears 29 (see particularly FIGURE 3) respectively arranged for engagement with the rear edges of two apertures 30, formed in the slam bolt 10, on rotation of the shaft 25 to displace the bolt 10 inwardly into the housing 1 to release the latch. The element 20 is located in the axial direction within the housing 1 and passes through an aperture 32 in the bolt 10 so that it provides an abutment towards which the bolt It) is urged by the latch spring 14. Thus engagement of the inner end of the aperture 32 limits the maximum outward projection of the bolt from the housing 1, and the apertures 30 are formed (as clearly shown in FIGURE 3) at the upper and lower edges of the aperture 32.

On assembly of each of the illustrated latches the bolt 10 and spring 14 are slid into the central bore 13 of the split portion 6 from the outer end of the latter, and the releasing element 20 is then fitted through the bolt aperture 32 into the bearing bore 22 in the portion 6. The smaller split portion 7 can now be fitted by inserting the lip into the central bore 13 of the portion 6 and bringing the split portions 6 and 7 together in a manner which engages the releasing element in the bearing bore 23 in the shorter portion 7.

With the arrangement of FIGURES 1 to 9, movement of the portions 6 and 7 together in the foregoing manner causes the spring arms 17a to snap around the circular end section 8 of the portion 6 to secure the portions firmly together in the radial sense, engagement of the lip 15 with the step 16 in the portion 6 providing axial location of the two portions; the step 16 engages a peripheral groove 33 in the portion 7 to assist such location. With the arrangement of FIGURE 10, after the portions 6 and 7 are brought together in the described manner the sleeve 13 is pushed on to the circular end section 3 to secure the portions firmly together. In this case the formation of the lip 15 does not provide relative axial location of the parts 6 and 7, and such location is provided by integral projecting dowels such as 34 moulded on the shorter portion 7 which engage corresponding bores in the wall of the longer portion 6 to ensure accurate location of the two parts. It will be appreciated that each of the described latches can be completely assembled very rapidly by hand without the need of special tools, jigs or the like. In addition, the

spring clip 17 or the sleeve 18 serves to hold the two portions 6 and 7 firmly together without the need for screws, rivets or other fastenings.

The locking means 28 include a detent or index bolt 35 urged towards the shaft 25 by a spring 36, and in each case the inner end of the bolt 35 and the spring 36 are housed within the central bore of the circular end section 3 of the housing which is thus of tubular form. During assembly, the bolt 35 and spring 36 are fitted in the longer split portion 6 before the shorter split portion 7 is fitted thereto.

I claim:

1. A door latch comprising a latch bolt, a tubular bolt housing which is split over an inner end section thereof to provide a main portion defining a guide bore in which said bolt is slidably mounted and a shorter portion which engages in a lip-like manner with the main portion at the commencement of said inner end section, the two portions being secured together at the inner end of the housing, and a latch spring the outer end of which acts on the bolt to urge the latter towards a latching position in which the bolt projects from said guide bore, said main portion being formed with an inner end spring abutment shoulder on one side of the bolt opposite said shorter portion and the lip-like end of said shorter portion being formed to provide a further inner end spring abutment.

2. A door latch according to claim 1, wherein the portions are secured together by a yoke-like spring clip with arms fixed to one of the portions and resiliently gripping the other portion.

3. A door latch according to claim 2, wherein the arms of the clip are attached to the shorter split portion.

4. A door latch according to claim 2, wherein the spring clip is moulded integrally with one of the split portions.

5. A door latch according to claim 1 wherein the housing has an inner end section of circular form and reduced diameter on which fits a sleeve securing the portions together.

6. A door latch according to claim 5, wherein the sleeve is moulded from a synthetic plastic material.

7. A door latch according to claim 1, wherein locating dowels or the like provide relative axial location of the split portions when the latter are fitted together.

8. A door latch comprising a latch bolt, a tubular bolt housing which is split over an inner end section thereof to provide a main portion defining a guide bore in which said bolt is slidably mounted and a shorter portion formed with an end lip which engages within the main portion at the commencement of said section to provide both radial and axial relative location of said portion, the two portions being secured together at the inner end of the housing, and a latch spring housed within said guide bore and the outer end of which acts on the bolt to urge the latter towards a latching position in which the bolt projects from said guide bore, said main portion being formed with an inner end spring abutshorter portion and the lipped end of said shorter portion providing a further inner end spring abutment.

9. A door latch comprising a latch bolt formed with an inner end lateral through aperture, a tubular bolt housing which is split over an inner end section thereof to provide a main portion defining a guide bore in which said bolt is slidably mounted and a shorter portion formed with an end lip which engages within the main portion at the inner end of said guide bore, the two portions being secured together at the inner end of the housing, a latch spring housed within said guide bore and vthe outer end of which acts on the bolt to urge the latter towards a latching position in which the bolt projects from said guide bore, said main portion being formed with an inner end spring abutment shoulder on one side of the bolt opposite said shorter portion and the lipped end of said shorter portion providing a further inner end spring abutment on the opposite side of the bolt, said housing portions further dening aligned bearing bores disposed respectively in said portions, and a releasing element of generally tubular form rotatably mounted in said bearing bores and passing through said bolt aperture, said element having a through aperture adapted to receive a latch-operating shaft and being formed with a projection which engages the bolt to effect inward releasing movement of the latter against said spring on rotation of the latch-operating shaft.

10. A door latch according to claim 9, wherein assembly of the housing portions around the releasing element serve to locate the latter in position within the housing.

11. A door latch according to claim 9, wherein an inner end portion of the housing houses a detent or index bolt and detent operating spring of latch locking means.

12. A door latch comprising a latch bolt, a tubular bolt housing which is split over an inner end section thereof molded from a synthetic plastic material to provide a main portion defining a guide bore in which said bolt is slidably mounted and a shorter portion which engages in a lip-like manner with the main portion at the commencement of said inner end section, the two portions being secured together at the inner end of the housing, and a latch spring the outer end of which acts on the bolt to urge the latter towards a latching position in which the bolt projects from said guide bore, said main portion being molded with an inner end spring abutment shoulder on one side of the bolt opposite said shorter portion and the lip-like end of said shorter portion being molded to provide a further inner end spring abutment.

References Cited by the Examiner 2,812,204 11/57 Squire.` 2,841,974 7/58 Hensel.

M. HENSON WOOD, JR., Primary Examiner.

Claims (1)

1. A DOOR LATCH COMPRISING A LATCH BOLT, A TUBULAR BOLT HOUSING WHICH IS SPLIT OVER AN INNER END SECTION THEREOF TO PROVIDE A MAIN PORTION DEFINING A GUIDE BORE IN WHICH SAID BOLT IS SLIDABLE MOUNTED AND A SHORTER PORTION WHICH ENGAGES IN A LIP-LIKE MANNER WITH THE MAIN PORTION AT THE COMMENCEMENT OF SAID INNER END SECTION, THE TWO PORTIONS BEING SECURED TOGETHER AT THE INNER END OF THE HOUSING, AND A LATCH SPRING THE OUTER END OF WHICH

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