Untitled record

V. B. CETRONE ETAL

LATCH MECHANISM

3,125,366

March 17, 1964

Filed Aug. n, ₁₉₆₀

Sheets-Sheet i

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ATTORNEY

3,125,366

March 17, 1964

V. B. CETRONE ETAL

LATCH MECHANISM

Filed Aug. 11, 1960

Sheets-Sheet 2

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3,125,366

Patented Mar. 17, 1964

United States Patent Office humidity, during an extended time under stress, or during exposure to most solvents, and it has no known equal, in a thermoplastic polymer at least, in its combination of dimensional stability, fatigue life, and recovery from de5 formation over a wide range of conditions.

To reduce the number of loose parts and to facilitate assembly, the cover 12 may have a plurality of tabs 23 (here four in number) extending in pairs from its opposite marginal edges, each tab terminating in a finger 10 24 (see FIGURE 6) adapted to snap into a respective opening 25 formed in the side edge walls of the receptacle portion 11. A slot 26 leads to the opening 25 to guide the respective finger 24 and receive the respective tab 23, and thus hold the cover in predetermined alignment with 15 the receptacle portion.

The housing 10 provides opposed side walls, one formed by means of the bottom of the receptacle portion 11 and the other formed by the attached cover 12, and these side walls are provided with aligned openings 27, 28, which 20 openings are also aligned with the usual door handle apertures 29 formed in the door 16 transverse to and communicating with the door recess 14.

A tumbler member 30 is rotatably carried within the housing 10 and has a hub 31 of a length to snugly fit 25 between the cover 12 and bottom wall of the receptacle portion 11, the hub having journals 32, 32 of reduced diameter at its opposite ends. The journals have a bearing fit with the aligned openings 27, 28 to properly support the tumbler member for rotation.

³θ The tumbler member is preferably formed of a rigid plastic, and the aforementioned Delrin has been found suitable for the purpose. A slot 33 is formed inwardly of one end of the hub 31 for a purpose to appear later. Extending from the hub are diametrically opposed pusher ³⁵ portions 34, 34, each terminating in a rounded extremity 35.

A latch plate 36 also preferably made of a rigid plastic, such as Delrin, is carried within the housing 10 and is preferably of a thickness to slidably fit between the cover ⁴⁰ 12 and the bottom of the receptacle portion 11. The latch plate has a generally rectangular portion 37 formed with an enlarged opening 38 therein to provide operating clearance for the tumbler member 30. The rear wall 39 of the latch plate 36 may be arcuate to clear the hub 31 ⁴⁵ and to be complementary to the rear wall 22 of the housing 10.

The latch plate opening 38 provides a pair of strike surfaces 40 which are cooperative with the pusher member extremities 35. A latch bolt 41 is preferably integral with and extends forwardly of the rectangular latch plate portion and outwardly of the housing 10 through an opening 42 in the front edge wall 17 of the housing. The latch bolt is preferably of a width and thickness to slidg5 ably fit within the opening 42 and against the cover 12 which closes such opening. An undercut neck 43 may integrally connect the latch plate portion 37 and latch bolt 41. In some instances, it is desirable to mold a hardened steel insert 44 within the latch bolt 41 to pre_fi0 vent easy sawing therethrough.

^ϋυ Resilient means normally projects the latch bolt in a direction outwardly of the housing 10 and such means are preferably of rigid plastic, such as Delrin. In the presently disclosed embodiment, the resilient means is integral with the latch plate 36 and comprises a pair of ⁶⁵ arcuate-shaped springs 45, either flat or of other crosssection. The springs 45 in this case extend symmetrically from opposite edges of the latch plate, preferably from the neck 43. The free end of each spring 45 is headed, Yq as shown at 46, to be slidably received within corresponding openings 47 (see FIGURE 6) formed in the front edge wall 17 of the housing 10. The latch plate 36 is

3,125,366 LATCH MECHANISM

Vincent B. Cetrtone, 563 Adelaide NE., Warren, Ohio, and Gerald H. Kreske, Warren, Ohio; said Kreske assignor to Vincent B. Cetrone, Warren, Ohio

Filed Aug. 11, 1960, Ser. No. 48,943 10 Claims. (CI. 292—169)

This invention relates to latch mechanisms, more particularly to such mechanisms for use with swinging doors, and the principal object of this invention is to provide new and improved mechanism of this character.

The present invention is a decided improvement over the prior art in that it reduces the number of parts required to provide an effective latch, and also minimizes the problem of corrosion because the majority, if not all, parts are formed of a rigid plastic material.

In the drawings accompanying this specification and forming a part of this application, there is shown, for purposes of illustration, an embodiment which this invention may assume, and in these drawings:

FIGURE 1 is a view of a latching mechanism disclosing a preferred embodiment, the cover of the housing having been removed to illustrate interior construction, and the housing being shown in position in a door, the latter being fragmentarily shown in section,

FIGURE 2 is a section corresponding to the line 2—2 of FIGURE 1, showing parts in one position,

FIGURE 3 is a section similar to FIGURE 2 but showing parts in another position,

FIGURE 4 is a section corresponding generally to the line 4—4 of FIGURE 1,

FIGURE 5 is an enlarged, fragmentary perspective view of a part of the preferred embodiment,

FIGURE 6 is a fragmentary enlarged perspective view showing details of the cover and cooperating receptacle, and

FIGURE 7 is a perspective view of a tumbler member forming part of the disclosed embodiment.

The presently preferred embodiment, as herein disclosed, comprises a housing 10 including a receptacle portion 11 and a cover 12. The housing 10 is generally oblong in plan and relatively narrow in thickness, so that it may fit, in customary manner, in the usual recess 14 formed inwardly of the free margin 15 of a door 16, such as one supported in the usual manner within a door frame by means of hinges. The door frame and hinge mounting may be conventional and are therefore not shown in the drawings. The front edge wall 17 of the receptacle portion 11 (see especially FIGURE 6) is formed with tabs 18, 18, each having an aperture 19 through which a fastening screw 20 is passed to hold the housing assembled with the door in usual manner.

The front edge wall 17 is undercut, as shown at 21 in FIGURE 6 to receive the cover 12 so that the latter is flush with all upper (in FIGURE 6) edges of the receptacle portion 11. The rear edge wall of the receptacle portion (see FIGURE 1) may have an arcuate outward bulge 22 for clearance of an internal working part hereinafter to be described.

The receptacle portion 11 and cover 12 are preferably formed of a rigid plastic for purposes of economy and to obviate ordinary corrosion caused by elements which may be in the atmosphere. As an example of a plastic found suitable for the purpose, a product of the E. I. du Pont de Nemours &amp; Company, sold under the trademark Delrin may be used. Delrin is an acetal resin, and is a high-melting, highly crystalline thermoplastic polymer. Delrin has both high tensile strength and high flexural modulus, which qualities are combined with excellent resilience and toughness. Delrin retains these fine properties under conditions of high temperature and

3,125,366 formed symmetrical so that it may be reversed in position within the housing 10, whereby the same construction may be used for doors closing in either direction.

Suitable door handles 50, 51 extend from opposite sides of the door in the usual manner, the handles in the dis- 5 closed embodiment having door knobs 52 for hand engagement. Handle shafts 53, 54 form part of the door handles 50, 51, respectively, and the latter may be made of rigid plastic, such as the aforementioned Delrin. Each handle shaft has a circular flange 55 and each has an 10 inner end disposed within the housing 10.

The inner end of handle shaft 53 is formed with stepped non-circular portions 56, 57 (see especially FIGURE 5), with the smaller portion 57 (smaller both in transverse size and length), closer to the inner terminal 15 end of the handle shaft. The portions 56, 57 are in this case of hexagonal cross-section and cylindrical end 58, reduced in diameter extends from the smaller portion 57, the terminal face of the end 58 having a cross-slot 59 formed therein. The larger hexagonal portion 56 has a 20 small part of its periphery rounded, as seen at 56α.

The larger hexagonal portion 56 slidably fits into a complementary portion 60 of the central opening through the tumbler member 30. The opposite end of the tumbler member opening is cylindrical, as at 61, to rotatably re- 25 ceive the cylindrical inner end of the handle shaft 54. The last mentioned inner end has a cylindrical axial opening 62 to rotatably receive the end 58, this opening having a hexagonal shaped entranceway 63 to closely but slidably receive the smaller hexagonal portion 57 of the han- 30 die shaft 53. An opening 64 provides communication between the opening 62 and the exterior of the door knob 52 of the shaft 54, for a purpose to appear later.

Trim discs 65 and 66 may be used to cover the apertures 29, 29 in the door 16 in the usual manner, each trim 35 disc being tightly held to the door by screws 67, one of which is shown in FIGURE 2. A coil spring 68 is interposed between trim disc 65 and flange 55 of handle shaft 53, to urge the latter in a direction toward the handle shaft 54 so that normally the smaller hexagonal portion 40 57 will seat within the entranceway 63 to couple the handle shafts for unitary rotation.

The trim discs 65, 66 may also be made of rigid plastic, such as Delrin. The spring 68 may also be made of like material and, in the case of Delrin, may be molded ₄integrally with the disk 65. From inspection of FIGURE ° 2, it will be evident that the handle shaft 53 may be moved downwardly a limited amount against the urging force of the spring 68, the amount of movement being sufficient to withdraw the smaller hexagonal portion 57 ₅₀from the entranceway 63 to thereby disengage the handle shafts so that only rotation of handle shaft 53 will effect operation of the tumbler member 30. Handle shaft 54, under these circumstances, may be rotated, but will not be effective to withdraw the bolt 41 from the usual keeper ₅₅(not shown). The handle shaft 54 is held against axial movement, in one direction by the flange 55, and in the opposite direction by abutment of the terminal face of its inner end with the shoulder between the hexagonal and cylindrical portions 60 and 61 of the opening in the tumbler member 30. ^w

Means are provided to releasably hold the handle shaft 53 in the retracted relation shown in FIGURE 3, and in the disclosed embodiment a lock arm 70 is integrally formed with the cover 12 and has a finger 71 (shown in _cphantom in FIGURE I) which extends through the slot 33 in the hub 31 of the tumbler member 30, and bears against the rounded peripheral surface 56α. The finger is resiliently pressed in a direction toward the axis of the handle shaft 53 and is adapted, when the shaft 53 is retracted, to snap into a recess 72 (see FIGURE 5) formed ^7Uin the end of the larger hexagonal portion. The recess 72 provides a shoulder 73 which engages the finger and thus holds the shafts retracted.

Sufficient rotation of the shaft 53 (slightly less than 75 degrees in the present case) will rotate the recess beyond the finger and, since no shoulder is then in line with the finger, the spring 68 will return shaft 53 to position wherein its inner end interfits with the inner end of the shaft 54 in driving relation. The latch thus described may be used as a bathroom lock, with the shaft 53 innermost of the room. In order that children cannot lock themselves in the bathroom without means of escape provided from the outside, a long, narrow screwdriver blade, or like tool, may be inserted into the opening 64 to seat in the slot 59 and thus provide means to rotate the shaft 53 from the outside of the room.

The latch parts are few and may be easily assembled. With the cover 12 removed, the latch plate 36 may be quickly and easily disposed within the housing 10 merely by inserting the headed ends 46 of the springs 45 into the corresponding openings 47 in the receptacle portion 11. The tumbler member 30 may then be disposed in position within the opening 38 in the latch plate 36 and with one journal 32 in the opening 28 in the receptacle portion. The cover 12 may then be snapped into place, the arm 70 having been manipulated to dispose the finger 71 into the slot 33 in the tumbler member 30. Thereafter, the handle shafts 53 and 54 are respectively inserted from the outer and inner sides of the door 16 and the screws 67 driven home. The latch is then ready for use. Since the parts, with the possible exception of the screws 20 and 67, are all formed of rigid plastic, the corrosion problem is largely overcome, and the latch may be used in places where rusting had heretofore made the life of a latch a short one.

In view of the foregoing, it will be apparent to those skilled in the art that we have accomplished at least the principal object of our invention, and it will also be apparent to those skilled in the art that the embodiment herein described may be variously changed and modified, without departing from the spirit of the invention, and that the invention is capable of uses and has advantages not herein specifically described; hence it will be appreciated that the herein disclosed embodiment is illustrative only, and that our invention is not limited thereto.