US2253257A - Door latch - Google Patents

Description

Aug-19,1941. a A, WELLMAN 2,253,257

DOOR LATCH Filed June 4, 1940 INVENTOR. 60 19. MEAL/Wm ATTORNEYS Patented Aug. 19, 1941 DOOR LATCH Guy A. Wellman, Geneva, Ohio, assignor to The Champion Hardware Company, Geneva, Ohio, a corporation of Ohio Application June, 4, 1940, Serial No. 338,760

6 Claims.

The present invention relates to door latches, more particularly screen door latches, and has for its objects the provision of a novel, simple, and reliable door latch which can be readily installed with common tools and with a minimum of cutting and fitting.

The invention resides in certain details of construction and combinations and arrangements of parts, and further objects and advantages thereof will be apparent to those skilled in the art to which the invention relates from the following description of the preferred embodiment described with reference to the accompanying drawing in which similar reference characters designate corresponding parts and in which:

Fig, l is a side elevational view of a door provided with a door latch embodying the present invention; 1

Fig. 2 is a sectional view approximately on the line 2-2 of Fig. 1;

Fig. 3 is a sectional view on the line 3--3 of Figs. 1 and 5, with portions shown in elevation;

Fig. 4 is a view similar to Fig. 3, but showing the latch bolt in retracted position;

Fig. 5 is a sectional view on the line 55 of Fig. 3; and

Fig. 6 is a sectional view on the line 66 of Fig. 3.

Referring to the drawing, the reference character A designates a door provided with a door latch embodying the present invention. The door latch shown comprises a cylindrical casing having a retractible latch bolt ll slidably supported in the forward end thereof and continuously urged into a projected position by a compression spring l2 interposed between a shoulder formed by the rearwardly extending, reduced shank I3 of the latch bolt H and a member l4 projecting through a slot I5 formed in the latch bolt proper. The forward end of the bolt II is beveled as at 16 so that the latch bolt will be moved inwardly as the beveled portion en ages the striker portion of a keeper when the door is closed. The keeper per se forms no part of the present invention and is not herein shown or described. Sufiice it to say that the keeper may be of any suitable construction as is well understood in the art.

The latch bolt II is adapted to be retracted by two members I! and i8 which, to some extent, resemble a longitudinally split sleeve having openings IS on opposite sides which provide clearance for the knob shaft 20 which extends transversely through openings in the side of the. casing 10 and is rotatably supported in the GSClltCh-r eon plates 2| and 22 secured to the front and rear of the door by screws 23 in the usual manner. Opposite ends of the knob shaft 20, which is square, as is the usual case, are provided with suitable knobs 25 and 26 of any desired form. The members I1 and I8 are moved relative to each other upon rotation of either of the knobs by'a gear 21 having a square aperture through which the knob shaft projects, the teeth of which gear engage within suitable slots 28 which form the equivalent of gear racks in the members l1 and [8.

The forward ends of the members I! and I8, that is, the left-hand ends as viewed in Figs. 3 and 4, are provided with inwardly extending projections or tongues 30 and 3|, respectively, which project into the slot IS in the shank 13 of the latch bolt I I from opposite sides of the latch bolt. When the latch bolt is projected, the projections 30 and 3| are positioned side by side in the slot I5, see Fig. 6, and are interposed between the member l4, previously referred to, and the rear wall 32 of the slot I 5. The rear ends of the members I1 and I8, that is, the right-hand ends as viewed in Figs. 3 and 4, are provided with inwardly extending projections or tongues 33 and 34, respectively, which lie side by side, seeFig. 5, when the bolt is projected and the members I! and H3 in the position shown in Fig. 3. The members I! and I8 are continuously urged towards the left, as viewed in Figs. 3 and 4, by a light cone-type compression spring 35 inter posed between an inwardly directed flange 36 on the rear end of the casing in and a disk member 31 slidably supported in the casing l0 and engaging the rear ends of the members I1 and [8.

The operation of the door latch is as follows: When either the knob 25 or the knob 26 is turned to rotate the knob shaft 2|] and in turn the gear 21, the members I! and I8 are moved relative to each other longitudinally of the casing Ill. The direction in which the members I! and 18 are moved depends upon the direction in which the knob shaft is rotated. Assuming that the knob shaft 20 is rotated in the counterclockwise direction, as viewed in Figs. 3 and 4, the member I! is then; moved towards the left, compressing the spring l2 through the medium of the projection or tongue 30 and the member l4. Simultaneously the member I8 is moved towards the right, retracting the latch bolt II by the engagement of the projection or tongue 3| on the member I8 with the rear wall 32 of the slot [5 in the shank l3 of the latch bolt. This movement of the latch bolt further compresses the spring l2 and the re-' sult is that the spring I2 is subjected to a double action which is highly desirable in devices of the character here involved, as will be hereinafter more specifically pointed out. The rearward movement of the member I 8 compresses the light cone-type spring 35 interposed behind the member 31 but this spring is relatively light as compared with the spring I2 and, if desired, can be omitted altogether. When the bolt II has been fully retracted, the parts are substantially in the position shown in Fig. 4. Upon release of the knob, the bolt will be projected and the parts returned to the position shown in Fig. 3 under the action of the springs I2 and 35.

In the event that the knob shaft is rotated in a clockwise direction, as viewed in Figs. 3 and 4, the operation of the door latch will be the same as mentioned above except that the members I1 and I8 will be moved in opposite directions, in which event the member I! will effect the withdrawal of the bolt through the medium of the projection or tongue 30 formed integral therewith and the spring 35 will be compressed by the member Ill. The fact that the projections or tongues 39 and 3I extend into an elongated slot in the bolt permits the latch bolt to be retracted upon engagement with a striker plate or either of the members I? and I8 to be moved forwardly without otherwise interfering with the operation of the device. When the latch bolt I I is retracted by the engagement of the beveled portion I6 thereof with the striker portion of the keeper, the rearward movement of the bolt is resisted by a single action of the spring I2, with the result that the latch bolt will operate more satisfactorily on light doors than would be the case if movement of the latch bolt Was resisted by the same force, irrespective of the manner in which it is retracted. When the latch bolt is retracted by engagement of the beveled surface I6 with the striker portion of the keeper, the only frictional resistance which it is necessary for the spring to overcome in returning the latch bolt to protracted position is that existing between the latch bolt proper and the casing I0, whereas when the latch bolt is retracted by rotation of either of the knobs, the friction of the entire mechanism must be overcome in restoring the latch bolt to protracted position, thus a heavier spring action is desired when the latch bolt is retracted by rotating one of the knobs than when it is retracted by the striker plate. As shown, part of this additional spring force is obtainedv from the spring 35, which is conical in shape, primarily for the purpose of saving space.

In applying the door latch of the present invention to a door, it is merely necessary to drill two holes, one into the side of the door large enough to receive the casing II] with a snug or forced fit, and the other at right angles to the first for the reception of the knob shaft. If desired, the first hole can be counterbored slightly to receive an outwardly extending flange 38 formed integral with the front end of the casing IE! which limits the distance that the casing Iii can be forced into the hole. When the knob shaft 20 is in position, forward movement of the bolt I6 under the action of the springs I2 and 35 is limited thereby and by the members I1 and I8. In order to maintain the bolt II, the members I7 and I8 and the gear 21, etc., in assembled relationship when the knob shaft 20 is removed, as for example, while the door catch is being applied to a door, provision is made for preventing rotation of the bolt assembly including themembers I1 and I8 in the casing I0 and. for limiting the forward movement of the bolt II relative to the casing I 0. As shown this means comprises a pin 39 fixed in the bolt I I and projecting into a longitudinal slot or opening 40 in the casing III but other suitable means may be employed. The projecting end of the pin 39 does not extend far enough through the slot 40 to interfere with the free operation of the bolt II. When the knob shaft 20 i removed, the spring 35 maintains the pin 39 in engagement with the front end of the slot 40 and the proportions or constructions are such that under these circumstances the aperture through the gear 27 is in alignment with the apertures in the casing I0 through which the knob shaft normally projects. These features of the present invention greatly facilitate the installation of the door latch because otherwise the parts would become disassembled during installation unless very carefully handled and difficulty would be encountered in aligning the aperture in the gear 27 with the openings in the casing Ill.

The preferred embodiment of the present invention shown also comprises means for preventing rotation of the knob shaft 20, thus making it impossible to open the door, in the form of a plate 4| slidably supported on the underside of the inside escutcheon plate 22 and provided with a keyhole aperture 42, the upper cylindrical part of which is large enough to permit free rotation of the knob shaft while the lower portion is adapted to engage the knob shaft and prevent rotation thereof. The plate 4| is adapted to be raised and lowered by a knob 43 fixed thereto, the shank of which projects through a suitable slot in the escutcheon plate 22. When the plate AI is in its down position, the knob shaft 20 projects through the cylindrical part of the keyhole aperture 42 but when the plate 4| is in its up position, the knob shaft 20 projects through the lower square portion of the keyhole aperture and rotation of the knob shaft i prevented. The fact that the plate ll is moved upwardly to lock the knob shaft against rotation prevents the plate 3| from being accidentally moved into locking position by vibration or jar, such as may be caused by slamming of the door. A small depression i l in the escutcheon plate 22 adapted to project either above the plate II or through the upper part of the opening 42, depending upon whether the plate is in its down or up position, helps to retain the plate in either of its two operating positions.

From the foregoing description of the preferred embodiment of the invention, it will be apparent that the objects heretofore enumerated have been accomplished and that I have provided a new and improved door catch which is simple in construction, reliable in operation and which can be readily installed with a minimum amount of effort. While the preferred embodiment of the invention has been described with considerable detail, I do not wish to be limited to the particular construction shown which may be varied within the scope of this invention and it is my intention to cover hereby all adaptations, modifications and variations thereof which come within the practice of those skilled in the art to which the invention relates.

Having thus described my invention I claim:

1'. A door latch of the character described comprising a casing, a latch bolt slidably supported in said casing, a plurality of members within said casing movable relative to each other and. to said casing for retracting said latch bolt, means including a shaft extending transversely through said casing and provided with a hand grasp for simultaneously moving said members in opposite directions longitudinally of said casing, a compression spring interposed betwen said latch bolt and the forward ends of said members whereby said spring is compressed by the forwardly moving member upon actuation of the first named means, and means for operatively connecting said latch bolt with the forward ends of said members whereby said latch bolt is retracted by the rearwardly moving member upon actuation of said first named means.

2. A door latch of the character described comprising a cylindrical casing, a latch bolt slidably supported in said casing, a plurality of relatively movable members within said casing for retracting said latch bolt, means including a shaft extending transversely through said casing and provided with a hand grasp for producing relative movement between said members longitudinally of said casing, a compression spring interposed between said latch bolt and the forward ends of said members, means for operatively connecting said latch bolt with the forward ends of said members, an abutment adjacent to the rear end of said casing, and a compression spring interposed between the rear ends of said members and said abutment.

3. A door latch of the character described comprising a casing, a latch bolt slidably supported in said casing and having a longitudinally extending slot therein, a member comprising two relatively movable parts slidably supported within said casing for retracting said latch bolt, means including a shaft extending transversely through said casing and provided with a hand grasp for simultaneously moving said parts of said member in opposite directions longitudinally of said casing, and a compression spring interposed between said latch bolt and the forward end of said member, said member having a portion extending into said slot for operatively connecting said latch bolt with said member.

4. A door latch of the character described comprising a casing, a latch bolt slidably supeluding a shaft extending transversely through said casing and having a hand grasp for simultaneously moving said members in opposite directions longitudinally of said casing, a compression spring interposed between said latch bolt and the forward ends of said members, projections on said members, and said latch bolt being recessed for operatively connecting said latch bolt with said members.

5. A door latch of the character described comprising a cylindrical casing, a latch bolt slidably supported in said casing and having a longitudinally extending slot therein, a plurality of relatively movable members within said casing for retracting said latch bolt, means including a shaft extending transversely through said casing and having a hand grasp for producing relative movement between said members longitudinally of said casing, a compression spring interposed between said latch bolt and the forward ends of said members, projections on said members extending into said slot for operatively connecting said latch bolt with said members, and a compression spring interposed between the rear of said members and the rear end of said casing.

6. A door latch of the character described comprising a cylindrical casing, a, latch bolt slidably supported in said casing and having a longitudinally extending slot therein, a plurality of relatively movably members within said casing for retracting said latch bolt, means including a shaft extending transversely through said casing to the rear of said bolt and having a hand grasp for producing relative movement between said members longitudinally of said casing, a compression spring interposed between said latch bolt and the forward ends of said members, pro- J'ections on said members extending into said slot for operatively connecting said latch bolt with said members, a compression spring interposed between the rear of said members and the rear end of said casing, and means for limiting the forward movement of said latch bolt when said transversely extending shaft is removed from said casing.

GUY A. WELLMAN.

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