US2978268A - Latch mechanism - Google Patents

Description

J. PICKLES LATCH MECHANISM April 4, 1961 Original Filed Feb. 7, 1955 2 Sheets-Sheet 1 ndE INVENTOR.

H PIOKLES JSEP ATTO RNEYS April 1961 J. PICKLES 2,978,268

LATCH MECHANISM Original Filed Feb. '7, 1955 2 Sheets-Sheet 2 INVENTOR. JO EPH PICKLES tor'med to*:provide= projections";

United States Patent 2,978,268 LATCH MECHANISM Joseph Pickles, Dearborn, Mich., assignor to Ferro Stamping Company, Detroit, Mich., a corporation of Michigan Original application Feb. '7, 1955, Ser. No. 486,477,

now Patent No. 2,925,297, dated Feb. 16, 1960. Divided and this application Dec. 19, 1957, Ser. No. 703,946 a s calm; or. 292-280) It is an object of the present invention to provide latch mechanism of the typehaving a latch rotor rotatable in one direction into latched position, and -roto maintain a tight'latchedrelation 2 equivalent to rack teeth conjugate to the generally involute teeth of the rotor 10. The housing 14 is shaped with an edge wall portion 24 to fit against the inner wall 26 of the recess 18.

In practical use the latch mechanism including the rotor 10 is preferably supported at the edge of a door with the axis of the rotor 10extending in the plane of the door. The keeper plate 16 is mounted at the edge of the door opening in position to receive the tooth portion of the rotor 10. Due to the upward inclination of the bottom wall 20, the door is firmly supported at its free edge and is retained in firmly latched relation by the provision of releasable means normally preventing rotation of the latch rotor out of the latched position illustrated in Figure 6.

It will be understood of course that the rotor 10 is provided for rotation in one direction during movement into latched position and for rotation in the opposite direction during movement out of latched position. In order to retain the door latched, releasable-means are provided preventing rotation of the latch member in the tatable in the opposite direction out of latched position,

in combination with releasable means normally preventing rotation of the rotor .out of latched position.

More specifically, it is an object of the present invention to provide latch mechanism including a latch rotor having a plurality of lobes thereon, a stationary-abutment adjacent the latch .rotor, and wedge cam means movableinto and out'of the space between the lobes on the rotor andthe abutment to 'prevent rotation of'the rotor-in unlatching direction.

It is a further object of the present invention'to'provide mechanism as defined in the preceding paragraph 7 latch alwaysfirmly supported against opening movement.

in which the lobes'and wedgecam means are constructed and arranged such that rotation of the rotor towards latched position operates to move the wedge cam out of the space between the lobes of therotorand the abutment.

Other objects "and features 'of'the invention 'willbe- Figure 1 direction required to accompany movement of the latch out of the latched position. In accordance with the present invention this releasable means is movable so as to take up slight additional increments of'rotation of the rotor toward latched position, and so to maintain the It is desired to emphasize that the present latch mechanism is operable to prevent opening movement of a door from a partially latched position and will take up so as to prevent slight opening movement of the door from further closed positions thereof.

The releasable mechanism for preventing rotation of I the rotor toward unlatched position comprises ,a pluralityof lobes 30 which are axially spaced from the teeth 12,0f the rotor. The lobes'30 may be formed as anintegral part of a unitary body includingthe teeth 12, or-they may be separately formed and rigidly attached I thereto. In the specific embodiment of the invention illustrateclthe latch rotor 10 is shown ,as provided with six involute latching teeth and as provided with three of the lobes which coact with other mechanism to prevent rota- ,tion of the latch toward unlatched position.

'Reference'is now made to Figure 5 which shows diagrammatically the relationship of parts entering into the retention of the rotor in latched position. As seen in this figure the lobes 30 each include'surfaces 32 which pref- Figure '1,lo0king to theright in Figure 5 is'a "diagrammatic view showingI-thejr'elationship of th e lobesand wedge earn. 1 s

Figure f6 is Lja "fia'grn'ehtary ele'vational view showing the relationship between the latching rotor and keeper.

The' latch mechanismtofwhich the present 'ifiven'tion relatesis of the typehavinga latchin'g rotor' indicated I generally" at "10 having a plurality'of latch teeth 12 which may conveniently ba in 1 the form of substantially involute gear teeth; Thelatch mechanism includes a partial housingj14and this housing arid the latch teeth 12 "jot the' rotorcoact tofirmly'support a door orother abutment pin 56. Since thesurface 54 isarcuate and the 7 closure-in themanneribe'st illustrated in Figure 6. In

this figure there is'illustratedakeeper 16 h'aving a recess "18 therein provid edjwith a sm ooth'slig htly upwardly inclined I bottom" Wall i20 and having' its upper surface I whichate x'generally v erably are constant rise cam surfaces, or in other words, involutesurfaces of a base'circle concentric with the axis of the rotor 10. The opposite sides 34 of the lobes are diiferently shaped for apurpose which will subsequently appear.. 7 .1,

'Associatedwith the lobes 30 of the rotor is a wedge cam element 40 including an arm portion 42 and a wedge cam portion .44, thesurface 46 of which 'is preferably also a oonstantrise cam surfacev or involute in profile.

.xThearm'42 is provided withan. elongated opening 48 receiving apin 50 which connects the arm 42 for rocking movement about the pin 50 but with provision for bodily movement longitudinallyiof the elongated .slot 48. The" arm 42". is provided'with an arcuate slot52 having a generally a'rcuate surface 54 'engageable with a fixed surface 46 is generally involute, these two surfaces converge and define therebetween the equivalent of .a wedgeinterposed between the cammingsurfaceBZ of "a lobe 30 and thesfixed abutment 56.,

'Froman inspection of Figure/5 it wilhbe apparent that the wedgelportion '44 of the element 40 is eifective to. prevent counterclockwise rotation of the rotor'10. It'

- willfal'sobe apparentthatforces tending to rotate the rotor counterclockwise produce camming forces tending to swing the wedge cam element 40 in a counterclockwise direction. However, such movement of the wedge cam element is frictionally opposed by the friction between the fixed abutment 56 and the arcuate surface 54, as well as the frictional forces existing between the lobe surface 32 and the camrning surface 46 of the wedge cam element .0. Since both of these frictional forces oppose carnming of the wedge cam element 40 in a direction to release the rotor 10, it will be apparent that the included angle between the surfaces 46 and 54 considered as a wedge may have a value substantially twice as great as the angle of repose for the materials of which the abutment 56, surface 54, surface 46, and surface 32 are formed. This permits a relatively great cam rise on the cam surface 46 for a correspondingly small angular movement of the arm 42.

As previously indicated, the surface 34 of the lobe is shaped differently from the involute side 32 thereof. The wedge cam device 40 is provided with a surface portion 58 cooperable with the side 34 and particularly the tip 60 of the lobes so that upon rotation of the rotor 10 in the direction resulting from movement of the lobe into latched position, the lobe rocks the wedge cam element 40 out of latching position.

By properly selecting the angular orientation of the lobes 30 with reference to the teeth 12, an arrangement results in which the latch rotor 10 cams the wedge cam device out of blocking position as the teeth 12 rollover the teeth 22 of the keeper until the housing 14 reaches the position illustrated in Figure 6. If the door is not completely closed so that the wall portion 24 of the housing is spaced from the end wall 26 of the recess in the keeper, the latch will operate to prevent opening movement of the door. If the door is thereafter caused to move by small increments, such for example as by vibration, further toward fully closed position, suitable spring means bearing against the wedge cam device 40 cause it to follow up so as to prevent return motion of the latch rotor from the furthest latched position which it reaches.

Referring now to a practical embodiment of the invention, the construction comprises an angular support plate 62 having a wall 64 normally disposed at the free edge of a door, and a wall 66 disposed at one side of the door. Where the latch mechanism is used in conjunction with an automobile, the wall 66 is normally located at the inner surface of the door. The wall 64 includes a rearwardly extending flange portion 68 to which is secured suitable lock mechanism indicated generally at 70 and includes an actuator 72 for'release of the latch as will subsequently appear.

The toothed portion of the latch rotor including the teeth 12 is partially housed within the housing 14 previously referred to, whichhousing includes. a mounting flange 74 welded or otherwise secured as indicatedat 76 to the outer surface of the plate 64. At the opposite side of the plate 64 from the toothed portion of the rotor 10 is provided the lobe portion thereof having the lobes 30, as best seen in Figure l-. Mounted in the plane of the portion of the rotor; containing the lobes 30 is a lever or arm 78, this arm being mounted for rotation about a pin 80 and including an enlarged opening providing .for some freedom of movement of the arm 73' in a direction perpendicular to the axis of the pin 80. The arm 78 is pro: vided with an arcuate slot 82 through which extends a fixed abutment pin 84-. A spring 86 is'provided surround quired to move the door to open position, the arm 78 is rocked in a clockwise direction, as seen in Figure l for example by pressure applied against the flange 90. In the practical door construction the flange 90 may be engaged by suitable actuating means such as a handle controlled lever or push button at the outside of the door.

The spring 88 is effective to cause the caming surface 2 of the wedge cam element 89 to follow up any move- 100 includes a projecting arm 110 which overlies the hook portion 106 of the wedge cam arm 78 so that the wedge cam arm 78 may be moved to latch release posi' tion by swinging movement of the actuating lever 109. The lever 100 includes the elongated slot 112 for con-- nection with the usual push button actuator provided on automobile doors, by means of which the lever 100 may be moved into and out of position to block release movement of the wedge cam arm 78.

From the foregoing description it will be apparent that: when mounted on the edge of a door as previously indi-- cated for coaction with the keeper plate as indicated in. Figure 6, the door may be slammed shut which will result in rotation of the latch teeth 12 relative to the stationary rack teeth 22 of the keeper plate. This rotation of the latch rotor 10 automatically shifts the wedge cam arm 78 out of wedging position, but the wedge cam arm moves back to wedging position under the influence of the spring 86 as soon as the door is closed. The wedging action of the wedge cam arm prevents any slightreverse rotation of the latching teeth and since the spring continues to urge the wedge cam arm in wedging direction, it will follow up any further additional incremental movements in rotation of thelatching teeth if the door moves slightly further toward latched position. In order to open the door it is necessary to release the wedge cam arm and this may be accomplished by swinging the wedge cam arm 78 in clockwise direction, as seen in Figure 1. This may be accomplished by pressing on the flange 90 of the arm through suitable outside handle mechanism or by inside remote control handle mechanism coupled to an opening indicated at 114 in the lever 100.

The drawings and the foregoing specification constitute adescription of the improved latch mechanism in such full, clear, concise and exact terms as toenable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

1. Latch mechanism comprising a latching rotor,

means mounting said rotor for rotation in onedirection during relative movement into latched position and for rotation in the opposite direction during relative movement into unlatched position, said rotor having a plurality of latch'lobes having friction surfaces thereon, a

ing the pin 80 and includes an end portion 88 engageable with a laterally bent flange 90 on the arm 78. With the parts in the position illustrated in Figure 1, it .will be apparent that rotation of the lobes 30 in a clockwise direction is prevented by the wedge action of the portion-of the lever intermediate the lobe 30 and the fixed abutment 84. The camming surface92 of the arm 78 engages the involute surface 94'of the lobe 305' I In order to free the rotor 10 for the free rotation refixed abutment adjacent said rotor having a stationary friction surface spaced radially from the lobes of said rotor, a friction cam having a leading end movable into the space between the friction surfaces of one of said lobes and said abutment, said cam having opposite friction surfaces converging at an acute angle toward the leading end thereof and engageable in simultaneous frictional contact with the frictionsurfaces of said abutment and rotor, a mounting arm to which said cam is fixedly secured, said arm having a pivot mounting spaced radially from-the axis of said irotor generally in'the direction of the'line joining the axis of said; rotor :and' said abutment to provide for movement of said cam generally transverse to said line, said pivot mounting including provision for movement of said arm longitudinally to insure friction engagement of said cam with both the friction surface of one of said lobes and with the friction surface of said abutment, said abutment comprising a pin, said cam having a substantially arcuate slot in which said pin is received, one side of said slot forming one of the pposite friction surfaces of said cam.

2. Latch mechanism comprising a latching rotor, means mounting said rotor for rotation in one direction during relative movement into latched position and for rotation in the opposite direction during relative movement into unlatched position, said rotor having a plurality of latch lobes having friction surfaces thereon, a fixed abutment adjacent said rotor having a stationary friction surface spaced radially from the lobes of said rotor, an arm pivoted adjacent one end and having at its other end a friction cam surface having a substantial cam rise with reference to its path of swinging movement, the friction surface of said arm being engageable in blocking and frictional engagement with friction surfaces of said lobes, said arm having remote from its pivoted end and adjacent its said other end a second surface slidably engaged with said fixed abutment and inclined with respect to the aforesaid friction cam surface at an angle greater than the effective angle of repose but less than twice the effective angle of repose for the materials of the engaged friction surfaces, and pivot means mounting said arm for swinging movement and including means provided for limited free movement of said arm in a direction transverse to the relatively inclined friction surfaces thereon.

3. Latch mechanism comprising a latching rotor, means mounting said rotor for rotation in one direction during relative movement into latched position and for rotation in the opposite direction during relative movement into unlatched position, said rotor having a plurality of latch lobes having friction surfaces thereon, a fixed abutment adjacent said rotor having a stationary friction surface spaced radially from the lobes of said rotor, an arm pivoted adjacent one end and having at its other end a friction cam surface having a substantial cam rise with reference to its path of swinging movement, the friction surface of said arm being engageable in blocking and frictional engagement with friction surfaces of said lobes, said arm having remote from its pivoted end and adjacent its said other end an arcuate slot substantially concentric with the axis of pivoting of said arm and in which said fixed abutment is located, the outer side of said slot frictionally engaging said abutment and forming a second surface inclined with respect to the aforesaid friction cam surface at an angle greater than the effective angle of repose but less than twice the effective angle of repose for the materials of the engaged friction surfaces, and pivot means mounting said arm for swinging movement and including'means provided for limited free movement of said arm in a direction transverse to the relatively inclined friction surfaces thereon.

4. Latch mechanism comprising a latching rotor, means mounting said rotor for rotation in one direction during relative movement into latched position and for rotation in the opposite direction during relative movement into unlatched position, said rotor having a plurality of latch lobes having constant rise friction surfaces thereon, a fixed abutment adjacent said rotor having a stationary friction surface spaced radially from the lobes of said rotor, an arm pivoted adjacent one end and having at its other end a friction cam surface having a constant and substantial cam rise with reference to its path of swinging movement, the friction surface of said arm being engageable in blocking and frictional engagement with friction surfaces of said lobes, said arm' having remote from its pivoted end and adjacent its said other end an arcuate friction surface slidably engageable with said fixed abutment and inclined with respect to the aforesaid friction cam surface at an angle greater than the elfective angle of repose but less than twice the effective angle of repose for the materials of the engaged friction surfaces, and pivot means mounting said arm for swinging movement and including means provided for limited free movement of said arm in a direction transverse to the relatively inclined friction surfaces thereon.

5. Latch mechanism comprising a latching rotor, means mounting said rotor for rotation in one direction during relative movement into latched position and for rotation in the opposite direction during relative movement into unlatched position, said rotor having a plurality of latch lobes having constant rise friction surfaces thereon, a fixed abutment adjacent said rotor having a stationary friction surface spaced radially from the lobes of said rotor, an arm pivoted adjacent one end and having at its other end a friction cam surface having a substantial constant cam rise with reference to its path of swinging movement, the friction surface of said arm being engageable in blocking and frictional engagement with friction surfaces of said lobes, said arm having remote from its pivoted end and adjacent its said other end an arcuate slot substantially concentric with the axis of pivoting of said arm and in which said fixed abutment is located, the outer side of said slot frictionally engaging said abutment and forming a second surface inclined with respect to the aforesaid friction cam surface at an angle greater than the effective angle of repose but less than twice the effective angle of repose for the materials of the engaged friction surfaces, and pivot means mounting said arm for swinging movement and including means provided for limited free movement of said arm in a direction transverse to the relatively inclined friction surfaces thereon.

References Cited in the file of this patent UNITED STATES PATENTS 2,243,282 Marple May 27, 1941 2,673,757 Marple Mar. 30, 1954 2,712,957 Marple July 12, 1955

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