GB2300447A - Locking mechanism for a roll-up door - Google Patents

Abstract

A locking mechanism for roll-up doors and the like (10) includes a hook member (13), Fig 1, and handle member (32), (Fig 2), mounted on the outside of a door, and a shoulder member (54), Fig 5, an arm, a lever (61) and a cam member (72) mounted on the inside of a door. The hook member is designed to engage a keeper (15) located on the floor of a container and has a lug (29) the handle member selectively engages as it rotates, thus causing rotation of the hook member. The hook member (13) is connected by a shaft (48) to the cam member on the inside of the door. When the cam member is locked against rotation by the lever, arm and shoulder member, attempts to rotate the hook member by rotation of the handle member will lead to breaking of the lug before the freeing of the cam member, shaft and hook member, thus, denying access to the container. The cam member is locked by the lever engaging a notch (71) in the cam member. The arm prevents forced rotation of the lever. The arm selectively rotates only in response to a tumbler rotating the shoulder member against a post (58) mounted on the arm.

Description

IMPROVED LOCKING MECHANISM FOR A ROLLUP DOOR The present invention relates generally to a door locking mechanism, and, more particularly, to an improved mechanism that provides improved security for upwardlyacting and roll-up doors commonly used with trucks, trailers and like by preventing forced entry.

Roll-up doors are ubiquitous. These doors are commonly found in garages, industrial buildings, and on trucks, trailers and other vehicles or containers. In such doors, a pair of inwardly-facing inverted L-shaped tracks are typically mounted on a body (i. e., a static structure, the body of a vehicle, etc.). A plurality of series-connected panels are operatively mounted for guided articulated movement along the tracks between a lowered substantially-vertical position closing the access opening, and an overhead substantiallyhorizontal out-of-the-way position.

The door, in its closed position, is traditionally lockable to a keeper provided on the floor of the body. A common locking device for such a door is a hinged hook attached to the lower portion of the door and designed to selectively engage the keeper in the floor of the body. A handle rotates independently of the hook, but selectively engages the hook to force its rotation freeing the door for movement. The hook is locked in its engaged position by providing the free end of the handle with a hole that registers with a hole in a fixture mounted on the door, and locking the handle and fixture together.

However, thieves developed two simple and effective ways to circumvent this locking system. The most straight forward method was cutting away the lock between the handle and fixture with bolt cutters. Recently, thieves learned to attack the handle instead of the lock. Traditionally, the handle was made of cast iron, a metal which becomes brittle when cold. A thief would spray liquid freon, or some other commonly-available gas, onto a portion of the handle, and strike the chilled portion with a heavy weight or tool, such as a hammer, causing the handle to shatter. Once the handle had broken, a portion was rotated, selectively rotating the hook, thus disengaging the hook from the floor keeper and allowing the door to open.

In an attempt to prevent the freeze-and-smash method, it was known to make the handle and hook from another metal, such as steel. However, steel is expensive compared to cast iron.

Accordingly, it would be generally desirable to provide an improved system to deter a thief access to a locked cargo container after the handle is shattered or the lock is cut away.

With parenthetical reference to the corresponding parts, portions or surfaces of the disclosed embodiment, merely for purposes of illustration and not by way of limitation, the improvement broadly provides an improved locking mechanism (10) for a roll-up door (11) having a hook member (13). The hook member has a lug (29) designed to breakaway when a predetermined force is applied by a handle member (32) without first unlocking a cam member (72), which is positioned on the inside of the door.

The handle member, hook member and cam member all rotate about the same shaft (48). When the hook member is engaged with a floor keeper (15) and the cam member is locked, rotation of the cam member and hook member is prohibited. If the cam member is not locked, rotation of the handle member selectively rotates the cam member and hook member.

Rotation of the handle member causes its leading edge (41) of the handle member to engage the lug. When the cam member is not locked, rotation of the handle member will abut the leading edge and the lug. Continued rotation of the handle member against the lug will cause the hook member and cam member to similarly rotate. In its locked position, a lever (61) prevents the cam member and the hook member from rotating. Accordingly, when a predetermined force is applied to the lug by the leading edge in an attempt to force the rotation of the hook member, the lug will breakaway, making the handle member incapable of selectively rotating the hook member. The lug is designed to fail before the lever or cam member. In a preferred embodiment, the lug is separate from the hook member, is attached to the hook member by a fastener (31), and is easily replaceable.

The invention further provides a unique lock to selectively prevent movement of the cam member and to prevent the accidental locking of the lock key inside the container. The lock comprises five major components: a tumbler (52), an arm (53), a shoulder member (54), the lever and the cam member. To lock the cam member, the right marginal end portion (70) of the lever (61) engages a notch (71) in the cam member. The lever is held in place by the arm. Rotation of the tumbler by a key rotates the shoulder member which, in turn, rotates the arm. Rotation of the arm causes rotation of the lever and its disengagement from the cam member notch. Thus, free rotation of the cam member and hook member is allowed. The arm will rotate until it engages a notch (60) in the lever.

Once free, rotation of the hook member makes the cam member act as a rising cam member forcing the further rotation of the lever, eventually freeing the arm from the lever notch and allowing its return to its original position. The lock can only be in its locked position when the arm is returned to the position where it enables the lever to prevent rotation of the cam.

The return of the arm to this position is accomplished by a spring (63) rotating the arm after it is freed from the lever notch.

Therefore, the general object of the invention is to provide an improved lock ing mechanism for roll-up doors and the like.

Another object is to provide an improved locking mechanism for a roll-up door capable of preventing access after the removal of the combination lock or the shattering of the handle.

Another object of the invention is to provide an improved locking mechanism to prevent unintentional rotation of the hook member by preventing the rotation of a con nected cam.

Still another object of the invention is to provide an improved lock mounted on the inside of a cargo container door having the improved locking mechanism mounted there on.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. I is a fragmentary elevation, partially cut away, of the outside of a roll-up door with the improved locking mechanism, shown without the handle member, mounted thereon; Fig. 2 is a fragmentary elevation similar to Fig. 1, showing the handle mem ber; Fig. 3 is a fragmentary sectional view thereof taken on line 3-3 in Fig. 2; Fig. 4 is a fragmentary sectional view thereof taken on line 44 in Fig. 1; Fig. 5 is a rear fragmentary elevation of the roll-up door, the mechanism being in its locked position; Fig. 6 is a fragmentary rear elevation similar to Fig. 5, except that the mechanism is shown in its unlocked position; ; Fig. 7 is a fragmentary rear elevation similar to Fig. 6, except the mechanism is shown in its unlocked and rotated position; Fig. 8 is a fragmentary elevation of an alternatively configured member having a lug connected to a handle member.

At the outset, it should be clearly understood that like reference numerals are intended to identify the same structural elements, portions or surfaces consistently throughout the several drawing figures, as such elements, portions or surfaces may be further described or explained by the entire written specification, of which this detailed description is an integral part. Unless otherwise indicated, the drawings are intended to be read (e.g., cross-hatching, arrangement of parts, proportion, degree, etc.) together with the specification, and are to be considered a portion of the entire written description of this invention.

As used in the following description, the terms "horizontal", "vertical", "left", "right", "up", and "down", as well as adjectival and adverbial derivatives thereof (e.g.. "horizontally", "rightwardly", "upwardly", etc.) simply refer to the orientation of the illustrated struc ture as the particular drawing figure faces the reader. Similarly, the terms "inwardly" and "outwardly" generally refer to the orientation of a surface relative to its axis of elongation, or axis or rotation. as appropriate.

Referring now to the drawings, and more particularly to Figs. 1, 2 and 5 the improved locking mechanism, generally indicated at 10, is shown mounted to the surface of roll-up door 11 that is arranged to selectively close an opening to a container. Door 11 is shown as abuning the floor 12 of the container. The improved locking mechanism has a portion mounted on the outside of the door, as shown in Fig. 1, and a portion mounted on the inside of the door, as shown in Fig. 5. 'The portion of the improved locking mechanism mounted to the outside of the door comprises hook member 13 and handle member 32. The portion of the improved locking mechanism mounted to the inside of the door comprises an arm 53, a shoulder member 54, an intermediately pivoting lever 61 and a cam member 72.

A rod 48 passes through door 11 and connects the outside and inside portions of the improved locking mechanism.

Adverting to Figs. 14, hook member 13 is a generally J-shaped member.

Hook member 13 is made of hot rolled steel, a material that must be cooled to a low temperature before it becomes brittle and susceptible to shattering. Other materials such as stainless steel could be used for hook member 13. Hook member 13 has a lower portion 14 adapted to engage keeper 15 in floor 12, and an upper portion 16. The opening of door 11 can only be accomplished when hook member lower portion 14 is rotated out of engagement with keeper 15. Otherwise, any vertical movement of door 11 is prevented by lower portion 14 engaging keeper 15.

Upper portion 16 is horizontally shorter and vertically wider than lower portion 14. An opening is located in the left marginal end portion 20 of upper portion 16 and is defined by inwardly-facing cylindrical surface 19 generated about horizontal axis x,-x,. A recess 21 extends downwardly into hook member 13 from its upper surface, and is sequentially defined by a rightwardly- and upwardly-facing planar surface 22, an upwardly-facing horizontal surface 23, and a leftwardly-facing vertical surface 24. A tapped blind hole 25 extends vertically downwardly from recess surface 23.

Dogleg-shaped member 26 fits into recess 21. As best shown in Fig. 1, member 26 has a base 28 and a lug 29. A hole 30 extends through base 28 and registers with hole 25. Member 26 is made of 6061-T6 Aluminum in this embodiment.

Turning now to Fig. 2 and 3, handle member 32 is made of cast ductile iron.

An opening is located in the left marginal end portion 33 of handle member 32 and is defined by inwardly-facing cylindrical surface 35 generated about horizontal axis x,-x,. The opening in handle member 32 defined by surface 25 is larger than the opening in hook member 13 defined by surface 19. As seen in Fig. 3, the right marginal end portion 36 of handle member 32 is generally U-shaped when seen in horizontal section. A hole 38 is provided through the right end portion of handle 32. When hook member 13 is engaged with keeper 15, as shown in Figs. 1-3, handle member 32 can be rotated to a position where hole 38 registers with hole 39 in fixture 40. Fixture 40 is attached to door 11 immediately adjacent the right marginal end portion 36 of the handle member.A standard lock (not shown) can then connect handle member 32 and fixture 40, thus prohibiting unintentional rotation of the handle member. When the handle member is free and is rotated in the counterclockwise direction, a leading edge 41 on the handle member will selectively abut lug 29.

Abutment of the leading edge and lug couples hook member 13 and handle member 32.

Thus, continued rotation of the handle member in the counterclockwise direction similarly rotates hook member 13.

As best seen in Fig. 3, a horizontal opening 42 generated about axis x,-x, between the outside and inside surfaces of door 11 is defined by inwardly-facing cylindrical surface 43. Sleeve 44 fits within opening 42. Sleeve 44 has a tubular portion 45 and a plate-like flange portion 46. The interior of tubular portion 45 is defined by inwardly-facing cylindrical surface 47. A shaft 48 is provided through tubular portion 45, the hook member opening defined by surface 19 and the handle member opening defined by surface 35. Hook member 13 and shaft 48 are fixedly connected for coupled rotation by a key/keyway system, while neither handle member 32 or tubular portion 45 are coupled with shaft 48.

Again, as best shown in Fig. 4, a second opening 49 is provided between the outside and inside surfaces of door 11 I generated about axis x2-x2. Cover plate 50 surrounds hole 49 on the outside surface of door 11 and has a hole 51 substantially the same size as hole 49 also generated about axis x2-x2. Tumbler 52 is positioned within opening 49 and hole 51.

Adverting now to Figs. 4-6, tumbler 52 passes through hole 51 and opening 49. Tumbler 52 has a portion passed through opening 55 in the lower marginal end portion 56 of arm 53. Just above opening 55 is a cylindrical post 58 mounted to and projecting perpendicularly away from arm 53. Upper marginal end portion 59 of arm 53 selectively engages notch 60 of lever 61 when arm 53 is rotated. Spring 63 acts to rotatably bias arm 53 toward post 64. Post 65 precludes further rotation of arm 53 in the counterclockwise direction.

Shoulder member 54 is a disk-like member having a flange 57 extending radially outwardly and is connected to the end of tumbler 52. When a key is inserted into tumbler 52 and rotated, shoulder member 54 rotates as well. During rotation in the clockwise direction, shoulder 57 of shoulder member 54 will contact cylindrical post 58 mounted to arm 53, thus coupling shoulder member 54 and arm 53 for further rotation in the clockwise direction about axis X3-X3. Shoulder member 54 will rotate arm 53 in the clockwise direction until end ponion 59 snaps into notch 60 of lever 61.

Lever 61 intermediately pivots about axis xrx,. Spring 69 rotatably biases lever 61 until arm 53 or cam member 72 prevents further rotation. The bottom surface of lever 61 has a notch 60 adapted to engage arm upper end portion 59. The right marginal end portion 70 of lever 61 is configured to engage notch 71 of cam member 72.

Cam member 72 acts as a rising cam when rotated in the clockwise direction.

Cam member 72 has an opening 73 generated about axis x-xss through which shaft 48 is passed. Cam member 72 is fixedly mounted to shaft 48 by a keylkeyway system. Because hook member 13 and cam member 72 are both mounted fast to shaft 48, hook member 13, shaft 48 and cam member 72 form an assembly where the rotation of one portion about axis x,-x, causes the rotation of the other portions.

Shaft 48 is also connected to an emergency hand wheel 75. A person who accidentally becomes locked in the container can use lever 76 and wheel 75 to rotate hook member 13 into its unengaged position. Lever 76 is connected to the bottom of arm 53.

Plate 78 prohibits direct manipulation of arm 53, lever 61 and cam member 72. However, end portion 79 of lever 76 is accessible at the left edge of plate 78. When lever 76 is rotated in the clockwise direction, it will eventually free lever right end portion 70 from recess 71 of cam member 72, allowing wheel 75 to rotate hook member 13.

Fig. 5 shows the improved locking mechanism in its locked position. Thus, the position of cam member 72 corresponds to hook member 13 engaging floor keeper 15.

To release hook member 13, cam member 72 must be rotated in the clockwise direction.

However, lever end portion 70 engaged to cam member notch 71 prevents rotation in the clockwise direction. In turn, lever 61 is held fast by arm 53. Finally, counterclockwise rotation of arm 53 is prohibited by post 65.

To unlock cam member 72, arm 53 is first rotated in the clockwise direction.

As previously described, rotation of the tumbler in the clockwise direction causes shoulder member 54 to rotate in the clockwise direction eventually abutting shoulder 57 to post 58.

Arm end portion 59 acts as a rising cam rotating lever 61 clockwise. When arm end portion 59 snaps into notch 60, cam member 72, shaft 48, and hook member 13 are unlocked and free to be rotated. Fig. 6 shows arm 53, shoulder member 54, lever 61 and cam member 72 in the unlocked position.

When arm 53 is engaged with notch 60, lever right end portion 70 rests just beyond cam surface 74 at the point of cam member 72 having the smallest radius. As cam member 72, shaft 48 and hook member 13 are rotated in the clockwise direction as seen in Figs. 6 and 7, cam surface 74 acts as a rising cam, causing further clockwise rotation of lever 61. Fig. 7 shows the position of arm 53, shoulder member 54, lever 61 and cam member 72 after hook member 13 has been rotated in the clockwise direction. At this position, arm end portion 59 no longer engages recess 60.

Once end portion 59 is free from recess 60, spring 63 will rotate arm 53 until it abuts post 65. This places arm 53 in its upright locked position as shown in Fig. 5. With arm 53 is in its upright locked position, counterclockwise rotation of cam member 72 will cause counterclockwise rotation of lever 61 until it abuts arm 53. In this position, lever end portion 70 engages notch 71 of the cam member, thus returning the improved locking mechanism to its position as shown in Fig. 5.

When cam member 72 and hook member 13 are locked, and handle member 32 is rotated until its leading edge 41 abuts lug 29, increasing the force of handle member 32 against lug 29 above a predetermined level will shear lug 29 away from base portion 28.

With lug 29 sheared away, handle member 32 is decoupled from hook member 13.

Lug 29 acts as a mechanical fuse," breaking at a predetermined force. This predetermined force is chosen to be less than that necessary to free cam member 72 from lever 61.

Because dogleg-shaped member 26 is connected to hook member 13 by fastener 31, member 26 can be quickly replaced if lug 29 is broken. To reset member 26 after lug 29 is broken away handle member 32 is rotated until fastener 31 is visible. Fastener 31 is removed, freeing the remainder of member 26 from hook 13. Once the remainder of member 26 is.removed from recess 21, a new dogleg-shaped member is positioned in recess 21 and a fastener is used to fixably mount the new member to hook member 13.

Modifications In the improved locking mechanism, the shape of the hook member need not be J-shaped. In addition, hook member 13 may be locked against rotation by means different then the arm-lever-cam combination disclosed.

Lug 29 need not be connected to hook member 13. A lug could easily be incorporated into handle member 32 and designed to engage a recess or protrusion of hook member 13.

An alternative member 80 is shown in Fig. 8 as being similar to dogleg-shaped member 26 except for additional legs, severally indicated at 81. Recess 82 of hook member 83 provides appropriate notches 84 to hold legs 81. Legs 81 provide additional strength to member 80 and reduce the stress placed on surface 85 of recess 82.

Therefore, while a presently-preferred form of the improved locking mechanism has been shown and described, and several modifications thereof discussed, persons skilled in this art will readily appreciate that various additional changes and modifications may be made without departing from the spirit of the invention, as defined and differentiated in the following claims.

Claims (10)

Claims

1. A locking mechanism for a door, said locking mechanism having a hook member mounted on said door for rotational movement about a first axis and operatively arranged to selectively hold said door in a closed position, said locking mechanism having a handle member mounted on said door for rotational movement about a second axis and selectively engageable with said hook member to rotate said hook member about said first axis, said locking mechanism also having locking means for selectively holding said hook member in a locked position, the improvement which comprises:: a frangible lug mounted on one of said members and engageable with the other of said members, said lug being so dimensioned and configured that at least a portion thereof will separate from said one member when a predetermined force is applied to said lug and said locking means holds said hook member in said locked position rendering said han dle member incapable of engaging said hook member for rotating said hook member about said first axis; whereby, after said lug separates, said members will be uncoupled.

2. A locking mechanism according to claim 1 wherein said handle member is cast iron.

3. A locking mechanism according to claim 1 wherein said hook member is hot rolled steel.

4. A locking mechanism according to claim 1 wherein said lug is removably mounted on said one member.

5. A locking mechanism according to claim 4 wherein said lug is replaceable.

6. A locking mechanism according to claim 5 wherein said member is said hook member, and said hook member further is provided with a recess, wherein a hole extends into said hook member from a surface of said recess, and wherein said lug is a portion of a recess-shaped member, said shaped member having a hole, and also configured to be arranged within said recess with said holes aligned, and said locking mechanism further comprises a fastener passing through said holes and holding said shaped member to said hook member.

7. A locking mechanism according to claim 1 wherein said door is a roll-up door

8. A locking mechanism for a door comprising: a handle member mounted on said door; a cam mounted on said door and connected to said handle member so that rotation of said handle member will selectively rotate said cam; a lever mounted on said door adapted to engage said cam, and biased to pre vent rotation of said cam; and an arm mounted on said door biased to maintain said lever in a position in which it locks said cam, and capable of moving said lever out of locking engagement with said cam, allowing free movement of said cam and handle member.

9. A locking mechanism according to claim 1 wherein said hook member is held in a locked position by a lock, said lock comprising: a cam mounted on said door and connected to said handle member so that rotation of said handle member will selectively rotate said cam; a lever mounted on said door adapted to engage said cam, and biased to pre vent rotation of said cam; and an arm mounted on said door biased to maintain said lever in a position in which it locks said cam, and capable of moving said lever out of locking engagement with said cam, allowing free movement Qf said cam and handle member.

10. A locking mechanism according to claim 1, substantially as described with reference to Figures 1 to 7 of the accompanying drawings, or as modified with reference to Figure 8.