US2711920A - Compound latch unit - Google Patents

Description

Jun@ 28 B955 W. Y. FARNSWQRTH COMPOUND LATCH UNIT Filed July 14, 1952 jam@ 2&9 lg W, y. g-"Awmgwgmwz ZJELZ@ COMPOUND LATCH UNIT Filed July 14, l952 3 SheetsSheet 2 rmfwir Fume 28, E955 Filed July 14, 1952 W. Y. FARNSWORTH COMPOUND LATCH UNITv 3 Sheets-Sheet 3 United States Patent 2,711,920 coMPoUND LATCH UNIT William Y. Farnsworth, Redwood City, Calif., assigner to Schlage Lock Company, a corporation Application July 14, 1952, Serial No. 298,703

' -3 Claims. (Cl. 292-169) My invention relates primarily to lock sets for doors and is especially concerned with a latch unit for use in a lock set of the type shown in Walter R. Schlage Patent No. 2,293,856, for example, as well as in other types of locks.

In the manufacture of a lock set for general installation on a door mounted to swing on hinges with respect to a door jamb, there is always an allowance made for the necessary clearance between the edge of the door and the'door jamb. Usually, the bolt is a latch bolt beveled along one face so that when the door is being closed the leading, beveled portion of the latch bolt strikes against the strike plate on the door jamb. This depresses the latch bolt against spring urgency as the door approaches closed position. The latch bolt then, under the'urgency of the just compressed spring, is projected into a recess partly defined by the strike plate and arranged in the door jamb. The amount of lengthwise movement or throw of the latch bolt with respect to the strike plate or door jamb is selected as an amount which will not require too much rotation of the operating handle or knob for easy functioning, yet which will permit'the latch bolt to project sufficiently into the strike box so as to afford adequate security. In some installations', particularly in connection with wooden doors and jambs and particularly in instances wherein the lumber utilized is not thoroughly'dried when erected, the initial clearance between the edge of the door and the door jamb increases, due to warpage and shrinkage of the door and jamb material, to anv amount which is nearly as great as the stroke or throw of the latch bolt. This reduces the amount of the latch bolt housed within the strike box and substantially reduces the security of the lock. Lock sets commercially supplied have a relatively standard stroke. It is difficult or impossible to increase the amount of stroke in a commercial lock set without either completely redesigning such set or making other drastic changes thereto.

It is therefore an object of my invention to provide a compound latch unit as a replacement for the stand ard latch 'unit of a commercial lock set having a predetermined stroke, to afford a latch bolt stroke or throw` of a greater amount.

Another object of my invention is to provide a latch unit affording an Aincreased amount of latch boltmovementffor a standard amount of actuator movement.

AV still further object of `my invention is to provide a compound latch unit easily interchangeable'with latch boltiinits presently available and of the` type shown in4 2,711,920 Patented June 28, 1955 rice more than usual stroke with a latch bolt having more than the customary stroke.

A still further object of my invention is to provide a compound latch unit interchangeable with a regular latch unit so that by the mere change of units a lock set can be adapted to a door installation having either normal or abnormal clearance between the door and th jamb.

A still further object of my invention is to provide in general an improved compound latch unit.

Other objects, together witth the foregoing, are attained in the embodiment of my invention, described in the accompanying description and illustrated in the ac-l companying drawings in which:

Figure l is a cross section through a compound latch unit according to my invention with a portion of an associated lock unit incorporated therewith, portions of the figure being broken away to reduce its size, and parts of the structure being shown in side elevation. The section of Figure 1 is on a vertical median plane.

Figure 2 is a cross section, the plane of which is indicated by the line 22 of Figure l, a portion of the structure being broken away to reduce the size of the ligure and to show subjacent parts.

Figure 3 is a cross section, the plane of which is indicated by the line 3--3 of Figure 1.

Figure 4 is a cross section, the plane of which is indicated by the line 4 4 of Figure l.

Figure 5 is a side elevation approximately duplicating Figure 1 but with additional portions being broken away and showing the latch bolt in a retracted rather than an extended position.

Figure 6 is a cross section substantially like Figures l dicated by the line 7--7 of Figure 6.

Figure 9 is a cross section, similar to Figure l, but

showing the modified form of device.

Figure l0 is a cross section, somewhat similar to Figure 3, but showing the modilied form of device, the plane of section being indicated by the line 10-10 of' Figure 8.

In the usual installation of a lock set there is provided a door panel 6 (Figures l, 5, 6 and 7), adapted to swing with relationship to a door jamb 7 (Figure 7). The door panel 6, usually of wood, is pierced by a transverse or through bore in which an actuator casing 8 is disposed. Knobs or other actuating instrumentalities operate a rotary spindle 9 about transverse axis 11 in either direction of rotation. The spindle 9 on its inner end is pro vided with a pair of projections 12 and 13 normally resting against abutting shoulders 16 and 17 on a slider 18 confined to rectilinear translation in an actuator frame 19 situated within the casing 8. The slider 18 is urged toward the edgeZl of the door panel 6 by a pair of coiled springs 22 and 23 arranged to abut against ledges 24 on a clip 26, forming part of the frame 19.

The shoulders 16 and 17 on the slider 1S are united .with actuator jaws 27 and 28 disposed opposite each other on the slider and translate in a rectilinear path with the slider. When the lock set is not actuated, the jaws 27 and 28 are in their left hand position (as seen in Figure l) and when the spindle 9 is rotated-in either direction, the jaws 27 and 2S are moved in a right hand direction (as seen in Figure l) and overcome the urgency of the springs 22 and 23. Thus upon rotation of the spindle the jaws 27 and 28 are advanced and retracted in a rectilinear path substantially from one edge of the casing 8 toward the central portion thereof. The standard amount of travel of the retractor is indicated by the arrow 31 in Figure l. The unit as so far described is substantially standard.

ln a normal installation, the door panel 6 is also provided with a circular cylindrical housing 32 having,

on its inner end a frame 33 with outturned prongs34 designed to interengage with the casing S with a lateral sliding motion to afford a rm interconnection between the casing and the housing. At its opposite end, the crcular cylindrical housing 32 is formed with an outwardly directed flange 36 received between a face plate 37 and a backing plate 38, recessed in the edge 21 of the door. A pair of fasteners such as screws 39 serve to hold the face plate 37 and the circular cylindrical housing 32 in the appropriate aperture or bore provided in the door. The screws 39 serve to conne the housing 32 against longitudinal movement just as the interconnection between the prongs 34 and the actuator casing 8 confine the housing 32 against rotary movement. Preferably the mounting is such that the central longitudinal axis 4l. of the housing 32 intersects the transverse axis 11 of the actuator unit and normally the axis 41 is disposed substantially midway between the sides of the door 6.

As shown especially in Figure 7, there is installed in the door jamb 7 a strike plate 42 bounding the edges of a strike box 433 comprised of a separate enclosing structure which serves as a lining for a depression or hole or recess in the door jamb. Sometimes the strike box is omitted but the strike plate remains. The location of the strike plate 42 is substantially in registry with the location of the face plate 37 when the door is closed.

Mounted for reciprocation in a predetermined path in the circular cylindrical housing 32 and in the direction of the central axis 41 is a latch bolt 46. rl`his latch bolt is substantially standard as to its external appearance in that it includes a relatively dat face 47 and has an adjacent cam curved face 48 both cut from a generally circular cylindrical body 49 symmetrical about the axis 41. The body 49 of the latch bolt is somewhat longer than previous practice and includes extensions 51 bearing against the inside surface of the housing 32 to afford a substantial support for the latch bolt not only when it is projected as shown in Figure l but also when it is retracted as shown in Figure 5. Preferably the movement of translation of the latch bolt is greater than the movement of the retracting jaws 27 and 28 and as indicated by the arrow 50 (Figure l) is approximately twice that of the actuator.

To assist in affording the desired increased movement I provide the latch bolt with a special latch bolt stud '52. This is primarily a hard bar having reduced and enlarged portions designed to cooperate with an off Center hole drilled in the deformable material of the latch bolt 46. The arrangement is such that when the bolt stud 52 is driven into the previously drilled hole in the latch bolt, some of the relatively soft material of the latch bolt is displaced into the reduced portion of the bolt stud and forms interlocking lugs 53. Once the assembly has been made, the latch bolt stud and the latch bolt are in effect an integral unit.

The latch bolt studr 52 at its inboard end is provided with a transverse pin 56 disposed to one side of the axis 41.in one aspect (Figure l) and also disposed slightly to one side of the central axis 41 from another aspect (Figure 2). The pin 56 is moved by forces exerted eccentrically on the pin but the extensions 51 of the latch bolt serve to withstand such eccentric loading.

In order to actuate the pin 56 and the latch-bolt, I provide a compound lever 57. This lever is essentially a plate provided adjacent one end with a pin 58 journaled in an appropriate bore formed in a boss 59 supported on the housing 32, there being provided an indentation 61 therein especially to serveas a base, the boss 59 in position, the rivet being a little loose Vso Zij that the boss 59 can be rotated to facilitate assembling the fulcrum pin 58 in the mounting boss 59. The opposite end of the compound lever 57 is provided with a peripheral notch 63 designed to interengage with the pin 56 with some lost motion.

Also projecting from the compound lever 57 is a pin 64 parallel to the pins 56 and 58 and disposed between them. The distance radially of the pin 64 from thc fulcrum pin S8 is less thanl (usually half) the distance of the pin 56 from the fulcrumj pin 58 in any position ol the pin 56. Engaged with the pin 64 is a retractor bar 66 having an elongated aperture 67 therein for that purpose. vThe other end of the retractor bar 66 extends through an opening in the housing 32 and terminates in un enlarged head 68 having a standard contour and lying immediately behind the jaws 27 and 28.

With this arrangement, when the spindle 9 is rotated in either direction and the slide 18 is consequently translated or retracted, the jaws 27 and 28 engaging the head 63 translate the retractor bar 66 and, after taking up any lost motion, rotate the compound lever 57 about the fulcrum pin S8 as an axis. The engagement of the wall t of the notch 63 with the pin 56 then produces a corresponding but greatly augmented rectilinear retraction or tr mslation of the latch bolt 46. The amount of translation of the latch bolt, as indicated by the arrow S0, is substantially twice the amount of translation of the head l 68 as indicated by the arrow 31. There are thus provided A riversa hoidsmeans for producing an augmented motion of the latch belt for a standard amount of motion of the retractor bar or of the knob spindle 9.

When the door is moved to a closed position, the latch bolt 46 is depressed as the cam surface 48 contacts the strike plate 42. The pin 56 then moves to take -up the lost motion in the notch 63, and rotates the compound lever 57, the pin 64 taking up the lost motion with the slot 67 and the retractor bar 66 being moved inwardly away from the jaws 27 and 28 as far as necessary. With this structure there is provided a latch bolt and its housing externally almost indistinguishable from and freely interchangeable with a standard latch bolt and housing. At

their interengaging portions, the compound latch bolt unit and the actuator unit t together in exactly the standard fashion, although there is provided a greatly augmented travel of the latch bolt itself with a standard rotation of the spindle.

The structure as so far described serves well as a plain latch bolt unit, and is shown slightly modified expressly for such service in Figures 8, 9 and l0. But often it is desired to have a dead latch function in addition so that the latch bolt cannot be externally depressed when thc door is closed. There is consequently provided a stop lever 71 having a rocker portion 72 in abutment with the frame 33 within the housing 32 and having extended and apertured bifurcations 78 and 79. These surround a'pair of pins 81 and 82 extending inwardly of the housing 32 from their mounting on the rear wall 83 thereof and on the frame 33. To hold the stop lever 71 in position and particularly to urge the bifurcat'ed portions towardv thc rear wall of the housing, a pair of compression springs 84 and 86 surround the pins and bear against a spring lever 87. A foot 88 on the spring lever 87 bears against the frame 33 within the housing and has a pair of lugs 89 and 91 pressing against the stop lever 71. -The force of the longitudinal springs 84 and 86 on the spring lever 87 is thus transmitted throughthe lugs 89 and 91 to the stop' When the parts are in the position. described, the latch bolt 46 can be externally forced into the housing 32 only in the amount of the lost motion between the end of the latch bolt stud and the tongue 92. It is impossible for the latch bolt to be translated sufficiently by external pressure, when the door is closed, to unlatch the door.

So that the latch bolt can be retracted under appropriate circumstances; that is, when the actuating unit is operated by rotation of the spindle 9 or when the open door is being closed, there is provided a means for preventing the dogging operation of the tongue 92 in the path of the latch bolt stud. This is accomplished by moving the tongue out of dogging position into another extreme position out of the path of the latch bolt stud. Upon operation of the spindle 9, the retractor bar 66 is retracted in the usual way and rotates the compound lever 57. On its periphery near the notch 63 the compound lever is provided with a cam 93 designed to ride under and against a cam follower 94 formed as part of and downturned slightly from the main body of the stop lever 71.

While there may be slight clearance between the walls of the notch 63 and the pin 56 and while there may be slight clearance between the ca m 93 and the cam follower 94, the relationship is such that upon initial operation of the retractor bar 66 and initial rotation of the compound lever 57, the lost motion is taken up and upon further rotation of the compound lever, the cam 93 acts to lift the cam follower 94. This rocks the stop lever 71 and lifts the tongue 92 out of the path of the latch bolt stud 52. The arrangement is such that the tongue 92 just lifts clear of the translating end of the latch bolt so that further movement of the retractor bar 66 finally moves the latch bolt 46 into fully retracted position.

When the spindle 9 is released, the latch bolt is projected again under the urgency of the spring 86 pressing against the inner face of the latch bolt. The other parts go through a reverse cycle of operation and the cam follower 94 follows the cam 93 as the compound lever rotates counterelockwise. dogged as the tongue 92 occupies its extreme position behind the latch bolt stud 52. In this fashion, while the latch bolt is normally deadlocked or dogged in deadlocked position when the door is closed, the operation of the spindle 9 serves to undog the deadlocked latch bolt r for normal operation.

A. similar effect is produced by a dead latching plunger 101 projecting through the same aperture in the face plate through which the latch bolt 46 projects. The plunger 101 is in effect a bar confined substantially to rectilinear translation in a path parallel to but alongside of the axis 41. The plunger has a foot 102 disposed behind the main body of the latch bolt 46, and terminates in a stud 103 disposed within the spring 84 and enlarged by a collar` 104 against which the spring presses. The collar is distinguished from the remaining part of the plunger by a groove 106 in which a fork 107 is fitted. This fork is on the leading end of a bar 108 extending longitudinally of the housing 32 and supported and guided in an appropriate aperture in the rear wall 83 and frame 33. The bar 108 intermediate its ends is contoured especially as shown in Figures 5 and 6, to provide an inclined cam 109 disposed to ride under the tongue 92 of the stop lever 71.

When the door is in closed position, as shown in Figure 7, the plunger 101 is held in its inner, longitudinal position by the strike plate 42 on the door jamb 7. When the plunger moves into its inner position, it not only comw presses the spring 84 but also, by reason of the interconnection of the fork 107 in the groove between the body of the plunger and the collar 104, it moves the bar 108 so that the cam 109 rides out from under the tongue 92. This permits the tongue 92 to drop into its lowermost position in the path of depression of the latch bolt stud 52. With the tongue in this position, the lock is dead- The latch bolt unit is again 6 latched or deadlocked in that the latch boltis dogged by' the tongue of the rocker lever 71.

When the door is in open position and there is no external force exerted against the plunger 101, the expanded spring 84 urges the plunger 101 outwardly until the foot 102 abuts the inner surface of the latch bolt 46. This outward motion is also imparted to the bar 108. Consequently the bar 108 moves the cam 109 under the tongue 92 and lifts it from its lower dogging position into its upper position out of the path of the end of the latch bolt stud 52. The latch bolt 46 is thereby freed for depression into the housing 32. The translational movement of the plunger 101 is in an augmented amount to correspond with the augmented movement of the latch bolt. The extra travel is utilized in the deadlocking or dogging operation by virtue of a corresponding proportioning of the cam surfaces and cam followers to produce the desired result.

As mentioned above, the structure is slightly modified if the deadlatching function is not required. As shown in Figures 8, 9 and l0, the housing 132 is, as before, concentric with an axis 133 and serves as a mounting for a retractor bar 134 identical with the retractor bar 66 and similarly connected to a compound lever 136 identical with the compound lever 57. A latch bolt stud 137, like the latch bolt stud 52 joins the compound levers to a latch bolt 138. This is generally similar to the latch bolt 46 but is not identical therewith.

The latch bolt 138 is formed from circular stock, has a central channel 139 to accommodate the compound lever and its attendant mechanism and is provided with a shoulder 141 abutting a face plate 142 having an aperture 143 therein only large enough for the latch bolt. A pair of springs 144 and 146 surround pins 147 and 148 mounted on the housing 132 and press against the end wail 149 of the housing and against the latch bolt 138, being received in circular bores 151 and 152 for that purpose.

Since it is desired that the parts be as nearly standard as possible, the opening 153 in the wall 149 is of sufficient width to receive a bar 108 (Figure 4) even though that part is not used in the absence of the deadlatching function. Excess lateral play might thus be permitted between the retractor 134 and the housing 132. To obviate that adverse factor, a spacer bar 154 is disposed in the opening 153 alongside the retractor 134 to occupy any excess space. The spacer bar has a turned circular head 156 disposed in the bore 151 between the latch bolt 138 and the spring 144 and consequently is approximately retained for travel in unison with the retractor 134. The operation of this modification is substantially the same as previously described except that there is no deadlatching function.

What is claimed is:

l. A latch unit comprising a housing, a latch bolt mounted in said housing for reciprocation along an axis from a projected position projecting outwardly from said housing to an inner depressed position substantially within said housing, a latch bar reciprocably supported in said housing for movement along said axis, a lever swingably secured at one end to said housing, means connecting the opposite end of said lever to said latch bolt for depressing the latter upon inward swinging of said lever, means on said lever intermediate said ends and connected with said latch bar for so swinging said lever upon inward movement of said latch bar, whereby the translatory movement of said latch bolt is greater than that of said latch bar, a dogging member, means urging said member to a position in the path of travel of said latch bolt when the latter is in projected position to prevent depression thereof, and means on said lever engageable with said member upon inward swinging of said lever for moving said member to a position out of said path permitting depression of said latch bolt.

2. A latch unit comprising a housing, a latch bolt mounted in said housing for reciprocation along an axis from a projected position projecting outwardly from said housing to an inner depressed position substantially Within said housing, a latch bar reciprocably supported in said housing for movement along said axis, a lever swingably secured at one end to said housing, means connecting the opposite end of said lever to said latch bolt for depressing the latter upon inward swinging of said lever, means on said lever intermediate said ends and connected with said latch bar for so swinging said lever upon inward movement of said latch bar, whereby the translatory movement of said latch bolt is greater than that of said latch bar, a clogging member, means urging said member to a position in the path of travel of said latch bolt when the latter is in projected position to pre vent depression thereof, and means on said lever engageable with said member upon inward swinging of said lever for moving said member to a position out of said path permitting depression of said latch bolt, said last mentioned means comprising a cam integral with said lever.

3. A latch unit comprising a housing, a latch bolt mounted in said housing for reciprocation along an axis from a projected position projecting outwardly from said housing to an inner depressed position substantially within said housing, a latch bar reciprocably supported in said housing for movement along said axis, a lever swingably secured at one end to said housing, means connecting the opposite end of said lever to said latch bolt for depressing the latter upon inward swinging of said lever, means on said lever intermediate said ends and connected with said latch bar for so swingingl said lever upon inward movement of said latch bar, whereby the translatory movement of said latch bolt is greater than that of said latch bar, a dogging member, means urging said member to a position in the path of travel of said latch bolt when the latter is in projected position to prevent depression thereof, a deadbolt reciprocably mounted alongside said latch bolt, means carried by said deadbolt for swinging said dogging member to a position out of the path of travel of said latch bolt when said deadbolt is projected.

References Cited in the file of this patent UNITED STATES PATENTS 1,876,081 Schlage Sept. 6, 1932 2,219,740 Hillgren Oct. 29, 1940 2,250,727 Schlage July 29, 1941 2,293,645 Falk Aug, 18, 1942 2,613,094 Schlage Oct. 7, 1952

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