US 5,666,830 A · Security lock, with free opening from indoors

Abstract

A security lock having a main locking bolt connected to a U-shaped tail member slidably mounted in a housing secured to the door. The U-shaped tail member has an upper branch engaged by a turnable driving arm for movement between a retracted unlocked position for the main bolt and an extended locked position therefor. A spring biasses the driving arm to move the U-shaped tail member to the extended locked position. A key cylinder and an interior handle are connected to the driving arm to turn the arm and unlock the bolt. A spring-loaded latch is biassed to engage the lower branch of the U-shaped tail member in the retracted unlocked position. In the closed position of the door, the latch releases the U-shaped tail member which, under the action of the spring, drives the main bolt to its locked position. The latch can be operated when the door is open to release the U-shaped tail member so the main bolt extends from the lock. A first security member at the inside of the door prevents opening of the door by the interior handle unless released. A second security member at the inside of the door prevents opening of the lock by the key.

Drawings

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Drawings

Claims16

Dependent claims

A security lock for a door comprising:

a housing attachable to a door,
a key cylinder operable by a key from outside the door to turn the key cylinder between locked and unlocked states,
a driving arm operatively coupled to said key cylinder for being turned therewith between said locked and unlocked states,
a main bolt operated by said driving arm for moving between locked and unlocked conditions of the door,
a turnable actuator accessible from an interior side of the door, said actuator being operatively connected to said main bolt via said driving arm to move the bolt between the locked and unlocked conditions of the door as the actuator is turned,
an armor plate covering said key cylinder outside said door, said armor plate having a key opening aligned with a further key opening provided in said key cylinder,
said bolt in said locked condition being in an outwardly projected state from said door and in said unlocked condition being in an inwardly retracted state in said door,
means for adjusting a length dimension of said bolt to vary its position in said projected and retracted states,
means connecting said bolt and said driving arm for operating the bolt by said driving arm comprising:
a U-shaped tail member connected to said bolt, said U-shaped tail member having upper and lower branches and a base connecting said branches, said bolt including a stem connected to said base,
said driving arm being engaged with said upper branch of said U-shaped tail member to displace said branch, and thereby said U-shaped tail member and the bolt connected thereto, upon turning of said key cylinder towards the unlocked state,
a first spring acting on said driving arm to bias said driving arm to said locked condition,
said lower branch of said U-shaped tail member having an opening therein,
a blocking arm pivotably connected to said housing and including a tooth engageable in said opening in said lower branch of said U-shaped tail member to lock said U-shaped tail member and said bolt in the unlocked condition of the door,
a second spring acting on said blocking arm to bias the blocking arm to engage said tooth in said opening,
a latch displaceably mounted in said door and positioned for undergoing movement to a displaced location when said door is closed,
a plunger connected to said latch and movable therewith such that when the door is closed, said tooth is moved out of said opening in the lower branch of said U-shaped tail member by said plunger and said first spring returns the bolt to said locked condition, and
locking means accessible from said interior side of the door for preventing the bolt from being moved to its unlocked condition, thereby maintaining the door in locked condition, even when the key cylinder is attempted to be turned by the key.

15 more elements

Dependencies are inferred from the claim text.

Description3,429 words

Summary1,052 words

#The present invention relates to a security means and more particularly to a lock for which has improved security and which is freely operable from the inside.

#In a conventional lock, a key is inserted into a key cylinder to rotate a driving arm which, in turn, displaces a security bolt into a locking recess in a door frame to lock the door to the frame.

#Such a lock may also include a spring bolt normally urged outwardly from the door, to act as a cam that is retracted when the door is closed.

Brief description of the drawings13 figures

#FIG. 1 is a cross-sectional view of the lock of the present invention.

#FIG. 1a is a front, top perspective view of a portion of the lock in FIG. 1.

#FIG. 1b is a top, plan view of another portion of the lock in FIG. 1.

Detailed description2,150 words

#Referring to the drawings, the security lock is comprised of a number of main sub-combination elements comprising a housing a, a key-operated actuator means b, a key cylinder c, a main bolt d, a blocking mechanism e to prevent rotation of an inside actuator handle 35 and a latch f.

#Referring to FIGS. 1-5 the security lock is applied to a door 1 and includes a guide plate 2 fixed to an edge of the door and provided with openings for passage of bolt d and latch f. The guide plate 2 is fixed to the door by screws 3. Mounted in a bore provided in the door 1 is the housing a. The housing a is in the form of a hollow box having walls 4. The key cylinder c has a body 5 with an end 6 for operating the actuator means b. The body 5 of the key cylinder c is covered at the outside of the door by an armor cover plate 7. The plate 7 is made of steel and is at least 3 mm thick. The plate 7 has a truncated conical shape to inhibit its engagement by tools. The body 5 of the key cylinder is supported by a support plate 7" and the support plate 7" and cover plate 7 are secured together by screws 8'. A slot 9 is formed in cover plate 7 for insertion of a key into a key slot 9' in the cylinder body 5. The slot 9 preferably has the shape of numeral eight. Spike screws 10 secure the cover plate 7 to the door 1. The screws 10 have square shank portions secured in the door to prevent rotation of the screws 10 from the outside. The ends of the screws 10 are partly recessed in the cover plate 7 so that only round heads 10' of screws 10 are exposed at the outside face of cover plate 7. Thereby, the heads cannot be readily engaged by tools nor can the screws be cut from the outside. The screws 10 are threaded at ends 11 and nuts 12 engage the threaded ends 11 to secure the cover plate 7 to a support plate 37 at the back of the door.

#The main bolt d comprises a stem 12 threadably engaged in a threaded bore in a head 13. Thereby, the overall length of the main bolt d can be adjusted by means of the threaded engagement between the head 13 and stem 12. A lock screw 15 secures the head 13 and stem 12 in an adjusted position for the length of the main bolt d. The stem 12 has a threaded end 16 connected to the base of a U-shaped tail member 25. The U-shaped tail member 25 has an upper branch 25a and a lower branch 25b connected by the base.

Security lock, with free opening from indoors

Life of this patent

Security lock, with free opening from indoors

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims16

Description3,429 words

Drawings

Classification18 codes

Life of this patent

Description3,429 words