US3458226A - Safety latch for doors,windows,and the like - Google Patents

Description

H. s. CARLSTON 3,458,226

SAFETY LATCH FOR DOORS, WINDOWS, AND THE LIKE 2 Sheets-Sheet 1 July 29, 1969 Filed April (5. 1967 HAM/LTUN S. CARLSTDN INVEN TOA jaw/7 M.

July 29, 1969 s CARLSTON 3,458,226

SAFETY LATCH FOR DOORS, WINDOWS, AND THE LIKE Filed April 6, 1967 2 Sheets-Sheet 2 27 606 IR 58 8 64: 6R H65 36 A TTORNEYS United States Patent 3,458,226 SAFETY LATCH FOR DOORS, WINDOWS, AND THE LIKE Hamilton S. Carlston, 1923 Fresno St., Fresno, Calif. 93721 Filed Apr. 6, 1967, Ser. No. 629,002 Int. Cl. Ec 17/16, 17/28 U.S. Cl. 292268 2 Claims ABSTRACT OF THE DISCLOSURE A safety latch having an axially positionable bolt mounted in a closure for selective releasable sliding connection through a slotted strap mounted on a frame for the closure limiting movement of the closure away from the frame to a partially opened position. The bolt is releasable from the strap to permit full opening of the closure only after the closure is returned to a fully closed position against the frame thus imparting a significant safety advantage to the latch.

Background of the invention Safety chain latches have long been employed on doors and the like to permit partial opening of the doors for ventilating purposes, inspection of callers, and the like.

Ordinarily, if installed correctly, the chain latch cannot be removed until the door is fully closed. Such chain latches, however, are not completely burglar-proof. If the door is opened only a slight amount, a relatively thin tool can be inserted through the opening to unlatch the chain. Furthermore, such chains are mounted in a continuously exposed position on the door frames which present an unsightly appearance and create some hazard to people passing through the doorway. These chain latches have not been readily adapted or accepted for use on sliding windows and other similar closures primarily because of the inconvenience involved in their use and their unsightly appearance. Furthermore the chain latches require an additional procedure when locking or unlocking the closure in that the fastener member on the end of the chain must be removed from the mounting bracket on the frame and slipped into the bracket on the door.

Accordingly, it is an object of the present invention to provide an improved safety latch for closures such as doors, windows and the like.

Another object is to provide an improved safety latch which is automatically actuated during the normal opening and closing procedures involving an associated door, window or the like.

Another object is to provide a safety latch of the character described which is substantially completely hidden when the closure is disposed in a closed position.

Another object is to provide an improved safety latch which is capable of constraining the closure in a partially opened position and which is not releasable until the closure is returned to its fully closed position.

Another object is to provide an improved safety latch which is conveniently installed, is economically produced, and is virtually burglar-proof.

Other objects and advantages of the present invention will subsequently become more clearly apparent upon reference to the following description .and accompanying drawings.

Brief description of the drawings position and a partially opened latched dashed line position.

FIG. 2 is a somewhat enlarged fragmentary front elevation of a slotted strap utilized by the safety latch of the present invention shown in a full line depending position aligned with the door frame when the door is closed and in an upwardly swung dashed line position when the door is disposed in its partially opened latched position.

FIG. 3 is a somewhat enlarged transverse vertical section, taken on line 3-3 of FIG. 1, through a turnbolt utilized by the present invention which is disposed within the door in adjacent relation to the strap of FIG. 2 when the door is closed.

FIG. 4 is a somewhat enlarged longitudinal vertical section, taken on line 44 of FIG. 1, showing the turnbolt disposed in a door locking position through the strap on the frame.

FIG. 5 is a somewhat enlarged horizontal longitudinal section, taken on line 5-5 of FIG. 4, showing the turnbolt in an intermediate full line door latching position and a fragmentary dashed line position with the door in its partially opened position.

FIG. 6 is a fragmentary front elevation showing a modified form of the present invention .adapted for use on a sliding window.

FIG. 7 is a transverse vertical section, taken on line '77 of FIG. 6, showing the safety latch in a window locking position.

Description of the preferred embodiments Referring more particularly to the drawings, a safety latch embodying the principles of the present invention is generally indicated by the reference numeral 10. The safety latch is associated with a substantially upright door 11 mounted for pivotal swinging movement within a substantially rectangular door frame 12 on a plurality of hinges, one of which is indicated at 14. The door includes an outer side edge 16 adjacent to which is mounted a conventional doorknob and main key latch set generally indicated by the reference numeral 18. The frame includes an elongated door bumper strip or stop 20 for positioning the door in closed relation within the frame. As best shown in FIGS. 4 and 5, the frame also provides a bore 22 in aligned relation with the safety latch 10 on the door.

As best shown in FIG. 2, the safety latch 10 provides an elongated strap 25 of substantially rigid, preferably hardened sheet steel material. The strap includes a mounting end 26 which is pivotally connected to a substantially rectangular mounting plate 27 in predetermined spaced substantially parallel relation by a rivet 28 and a spacer washer 29. The mounting plate is morticed into a recess in the edge of the frame opposite to the edge of the door 11 and is constrained in such position by a plurality of wood screws 30 having countersunk slotted heads 32 disposed in spaced ordered arrangement in the plate. The.

mounting end 26 of the strap has a plurality of arcuate notches 34 and a corresponding arcuate protuberance 35 adjacent to one of the notches. As best shown in FIG. 2, the notches are positioned so as to expose the upper screw heads 32 for installing the strap on the frame in its full line depending position. It will be noted that when the strap is swung upwardly to the dashed line position of FIG. 2, the screw heads are covered by the mounting end of the strap and by the protuberance 35. The strap further in cludes a circular bore 36 therethrough which, in the position shown in FIG. 2, is aligned with a corresponding bore -37 in the mounting plate and with the bore 22 in the frame 12. An elongated slot 38 of a width somewhat smaller than the diameter of the bores 36 and 37 is formed in the strap and provides an opposite closed end 39.

The safety latch 10 further includes a turnbolt assembly generally indicated by the reference numeral 45, which is mounted adjacent to the outer edge 16 of the door 11. The turnbolt assembly provides an elongated tubular barrel 46 which is rigidly mounted within a bore 47 formed in the outer edge 16 of the door. An elongated bolt 50 is axially slidably disposed within the barrel and has an elongated notch 52 providing therein a toothed rack segment 54. A turnknob 56 is rotatably secured to the face of the door 11 by a screw-mounted escutcheon plate 57. The turnknob has an inwardly extended splined pinion end 58 disposed in meshing relation with the toothed rack 54 of the bolt.

The bolt 50 further includes an elongated plunger 60 slidably disposed within a bore 62 therein which terminates short of the notch 52. The plunger is of a diameter slidably to be received within the slot 38 of the safety strap 25. The plunger has an outer circular head 64 which is disposed in predetermined axially spaced relation to the outer end of the bolt when the plunger is inwardly disposed against the bottom of the bore 62 to form an annular groove 65. The plunger includes an elongated slot 66 through which is transversely extended a retaining pin 67 having opposite ends rigidly mounted in the barrel 46. A compression spring 68 is mounted within the plunger between its inner end and the pin providing a force normally urging the plunger to its retracted position within the bolt.

Operation of the first form The operation of the first form of the subject invention is believed to be clearly apparent and is briefly summarized at this point. With the door 11 disposed in its closed position of FIG. 1, the turnknob 56 is rotatably manipulated to extend the bolt to the right, as viewed in FIG. 4. Such movement extends the bolt through the circular bores 36 and 37 in the strap 25 and the mounting plate 27, respectively, and into the bore 22 of the door frame 12, thereby locking the door in its closed position relative to the frame. Upon rotation of the knob 56 in the opposite direction, the bolt is retracted inwardly into the barrel 46 to a fully concealed position with the head 64 of the bolt disposed flush with the outer edge 16 of the door. It is obvious that with the bolt in its maximum retracted position, the door 11 can be swung to its fully opened position without restriction.

The knob 56 may be rotated from either of the above described maximum extended and retracted positions to an intermediate setting to dispose the annular groove 65 formed between the head 64 of the plunger 60 and the outer end of the bolt 50 in alignment with the plane of the strap 25. Accordingly, when the door 11 is swung toward its opened position, the plunger 60 is carried along the slot 38 for longitudinal sliding movement toward the closed end 39 of the slot. During such movement, the strap is pivoted about the rivet 28 and is swung upwardly by such outward swinging movement of the door from the frame. As the strap approaches the dashed line position of FIG. 2, the arc of the door causes the edge 16 of the door to move somewhat away from the strap 25. This movement is accommodated by compression of the spring 67 and extension of the plunger 60 outwardly from the bolt 50, as shown in FIG. 5. Such outward swinging movement of the door is terminated upon engagement of the plunger with the closed end 39 of the slot 38 dependably to hold the door in a partially opened position. As previously noted, with the strap 25 disposed in its upwardly swung dashed line position of FIG. 2, the screw heads 32 are covered by the mounting end 26 of the strap to preclude removal of the screws when the door is disposed in the described partially opened position.

If it is desired that the door be swung to its fully opened position, the safety latch requires that the door be first returned to its fully closed position wherein the bores 36, 37 and 22 are aligned for free axial movement of the bolt 50. The turn knob 56 is then rotated in the appropriate direction fully to retract the bolt into the barrel 46 and for retraction of the head portion 64 of the plunger 60 from the circular bores 36 and 37 in the strap 25 and the plate 27, respectively. If the turn knob is left in its intermediate safety latching position, the described movement of the plunger 60 through the slot 38 in the strap is automatically effected during each successive opening and closing of the door. Accordingly, the safety latch remains in operation until the turn knob is positioned for either locking the door by extension of the bolt into the bore 22 within the door frame 12 or the bolt is retracted into the door so as to enable the door to be fully opened but only from its fully closed position.

Second form A second form of the safety latch of the present invention is shown in FIGS. 6 and 7. In this form, a safety latch generally indicated by the reference numeral 80, which is substantially identical to the safety latch 10 of the first form, is adapted for use on a sliding window 82. The window provides a sash 83 having opposite sides, one of which is shown at 84, and opposite upper and lower portions, the latter of which is indicated at 85. The lower sash portion has an elongated downwardly opening recess 88 and is disposed for horizontal sliding movement within a window frame 90 providing a lower track 92. A bore 93 is formed within the lower sash portion beneath the side portion 84 of the window sash disposed in the closed position of FIG. 6.

The safety latch 80 is mounted in the side portion 84 of the sash 83 and includes an elongated barrel having a bolt 102 axially slidably disposed therein. The bolt is actuated by a turn knob 104 having an inwardly extended splined pinion end 105 extended through the bolt in meshing relation with a toothed rack segment 106. As in the first form, the knob is rotatably constrained in such position on the window sash by an escutcheon plate 108 having a plurality of screws 109 extended into the sash. The bolt 102 includes a head portion 111 which is extendible into the bore 93 of the frame in order to lock the window in the closed position. An annular groove 114 is formed in the bolt closely adjacent to the head 111 to provide a reduced diameter portion 115.

An elongated safety strap having a circular bore 122 and an elongated slot 124 having a closed end 125 identical to the strap 25 of the first form is mounted within the track 92 of the frame by a mounting plate 126. The plate has a circular bore 127 aligned with the bore 122 in the strap and with the bore 93 in the frame. The bores are of a diameter permitting free movement of the bolt 102 therethrough and into the recess. It is noted that in such sliding window installation, the strap 120 need not be pivotally mounted on the plate 126 and the spring 67 and plunger 60 within the bolt 50 of the first form are not required.

Operation of the second form The operation of the second form is substantially identical to the operation of the first form in that the bolt 102 is manipulatable by the knob 104 to three positions permitting locking of the window in its closed position, movement of the window to its fully opened position, and an intermediate partially latched position. It is apparent that the bolt is only manipulatable with the window disposed in its closed position of FIG. 6 wherein the bolt is free to be axially shifted to any one of the three above described positions. In order to limit movement of the window to its partially opened position, the knob is actuated to lift the bolt upwardly within the window sash to a position aligning the groove 114 in the bolt with the elongated slot 124 in the strap. The window may then be slid to the left, as viewed in FIG. 6, during which time the reduced diameter portion 115 of the bolt is permitted to slide through the elongated slot until abutting the opposite closed end 125 thereof.

It is further apparent that with the sliding connection provided between the groove 114 and the slot 124, the bolt is precluded axial movement until the window sash is returned to its closed position and the bolt again aligned with the circular bores 122 and 127 in the strap and plate, respectively.

In view of the foregoing, it is readily apparent that the structure of the present invention provides an improved safety latch for doors, windows and the like which is capable of restraining the closure in a partially opened position and which is not releasable until the closure is returned to its fully closed position. The safety latch is virtually burglar-proof in that all the mounting screws are covered by portions of the latch when the closure is disposed in its partially opened position. Furthermore, with the exception of the actuating knob, the safety latch is completely hidden from view by the elimination of the externally mounted chain or strap structures of the prior art.

Although the invention has been herein shown and described in what are conceived to be the most practical and preferred embodiments, it is recognized that departures may be made therefrom within the scope of the invention.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A safety latch, for a pair of members mounted for relative spacial movement, comprising a planar substantially rigid limit strap having a slot and being pivotally mounted on one of said members for movement between retracted and extended positions; and a slidable bolt mounted on the other of said members having a head with a reduced portion slidably received in the slot of the strap, said head being telescopically mounted within the bolt,

stop means within the bolt, and a compression spring disposed between said stop means and the head urging said head toward a retracted position within the bolt and permitting extensible outward travel of the head to accommodate movement of said other member away from the strap as the head travels along the slot.

2. A safety latch, for a closure pivotally mounted in a closure frame and having a predetermined swinging path of movement between open and closed positions with said latch permitting partial opening of the slosure but precluding full opening from such partially opened position until after first fully closing the same, 'comprising a planar substantially rigid strap having an inner end pivotally mounted on the frame and an outer end swingable outwardly from the frame in adjacent relation to the path of movement of said closure to and from said closed position, said strap having an elongated longitudinal slot therein providing a circular bore at the inner end thereof of a diameter somewhat larger than the width of the slot and an opposite closed end; an axially adjustable bolt mounted in the closure substantially radially thereof for extension through said circular bore in the strap when the closure is substantially in its closed position with the bolt having an elongated axial bore; an elongated plunger having an inner portion slidably fitted to said bore in the bolt and an outer portion outwardly extended from the bore for sliding movement through said slot of the strap and including a flanged head disposable through said circular bore and slidably engageable with the side of the strap opposite to said bolt for engagement with said closed end of the strap for limiting movement of the closure to said partially open position, said plunger having an elongated axial slot; a stop pin mounted in the bolt and transversely extended through the slot in the plunger to limit inward movement of the plunger into said bolt; and a compression spring disposed within said slot in the plunger between said stop pin and the opposite end of the slot adjacent to said inner end of the bolt normally to urge the plunger toward a retracted position within the bolt but being compressible to permit outward extendible movement of the plunger to accommodate arcuate swinging movement of the closure away from the strap incident to movement of the plunger through the slot in the strap during movement of the closure between its closed and its partially open positions.

References Cited UNITED STATES PATENTS 1,673,189 6/1928 Frank 292-268 2,010,461 8/1935 Milligan 70143 2,369,136 2/1945 Chambers 292-268 2,704,684 3/ 1955 Kleinemeier -a 292-268 388,074 8/1888 Reardon 292269 2,030,916 2/1936 Gard 292269 FOREIGN PATENTS 322,971 7/ 1920 Germany.

MARVIN A. CHAMPION, Primary Examiner E. I. McCARTHY, Assistant Examiner

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