US 3579910 A
Description (OCR text may contain errors)
United States Patent Allan E. Wetter Bloomfield Hills, Mich. 81 1,175
Mar. 27. 1969 May 25, 1971 Byrne Doors, Inc. Ferndale, Mich.
Inventor App]. No, Filed Patented Assignee LOCKING MEANS FOR A VERTICALLY MOVABLE DOOR 11 Claims, 4 Drawing Figs.
US. Cl 49/322, 49/449, 188/189 Int. Cl E05d 17/00 Field of Search 188/189;
deKoniny et al. 187/81 Primary Examiner-George E. A. l-lalvosa Attorney-Whittemore, Hulbert & Belknap ABSTRACT: Safety latch means for locking a vertically movable door against accidental descent. A latch carried by the door has a notch which normally freely receives a guide angle flange extending along the path of door movement. The latch turns or cocks to cause the notch to bind upon the flange and lock the door against accidental descent in response to the failure of the cable.
LOCKING MEANS FOR A VERTICALLY MOVABLE DOOR SUMMARY OF THE INVENTION It is an essential object of the invention to provide an improved safety latch structure for a vertically movable door whether of the single-leaf or multiple-leaf type.
Another object is to provide a safety latch structure which is dependable and sure in its operation.
Another object is to provide a safety latch structure which operates in response to cable failure, whether one or both cables fail.
Another object is to provide a safety latch structure having a latch provided with a notch which normally freely receives a flange extending along the path of door movement, but which cocks or turns to cause the notch to bind upon the flangc and lock the door against accidental descent in response to failure of one of the operating cables.
Another object is to provide a safety latch structure which will operate satisfactorily even in installations where the door is loosely mounted in the jambs and tends to cock when one of the two cables fails.
Another object is to provide a safety latch assembly which can be applied to existing doors without the need for modification of the jamb structure.
Another object is to provide a safety latch structure in which the latch utilizes one of the guide angle flanges of the jamb assembly upon'which tolock.
Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, wherein:
FIG. 1 is a front elevational view of a vertically movable door assembly incorporating the safety latch structure of my invention.
FIG. 2 is an enlarged fragmentary view of a portion of FIG. I with parts broken away and in section, illustrating one of the safetylatch structures.
FIG. 3 is a view of the safety latch structure of FIG. 2 as viewed from the right.
FIG. 4 is a view of the safety latch structure shown in FIG. 2 as viewed from above.
Referring now more particularly to the drawings, the door there illustrated is generally designated and in this instance is in the form of a single leaf disposed vertically and guided for vertical movement by the vertically extending jamb assemblies 12 and 14 which may be of identical construction. It will be understood that the invention may also be applied to a door of the multiple-leaf type.
The jamb assembly 12 is more clearly illustrated in FIG. 4 and is seen to have an upright jarnb guide 16 provided with the guide angles 18 and 20. The guide angles 18 and 20 have the laterally spaced vertically extending flanges 22 and 24 which closely receive one side edge of the door. It will be understood that the other jamb assembly 14 may be of the same construction and may guide the opposite side edge of the door 10 in the same manner.
The door 10 is raised and lowered by a power device or motor 26 whichdrives a shaft 28 having a drum or sheaves 30 secured thereto. Cables 32 and 34 extend from the sheaves or drum 30 to the opposite side edges of the door, cable 34 extending from sheave'30 over the intennediate freely rotatable sheave 36 as indicated in FIG. I. These cables 32 and 34 are connected to a suitable counterweight 38 which is guided for vertical movement along one side of the door opening as is customary and as is shown in FIG. 1. The cables 32 and 34 are connected to the opposite side edges of the door to sustain the weight of the door and are thereby held in tension, and operation of the motor drive 26 causes the door to be raised or lowered through the cables.
The door 10 has two safety latch structures indicated at 40 and 42 which are mirror images of one another and therefore only the latch structure 40 will be described in detail. The latch structure 40 is fully illustrated in FIGS. 2, 3 and 4 and includes a mounting member 44, latch 46 and detent 48. The mounting member 44 comprises an elongated generally vertical suspension arm 50 having a mounting block 52 secured thereto near the lower end. The mounting block is pivoted to brackets 54 on the door by a pin 56. Pin 56 is horizontal and extends normal to the plane of the door. The lower end of the cable 32 is connected to the upper end of the suspension arm 50. The suspension arm is under spring tension by a tension coil spring 58 which has one end connected to the lower end of the suspension arm and the other end connected to a mounting bracket 60 secured to the door. The tension spring 58 applies a constant turning moment or torque upon the suspension arm 50 in a counterclockwisedirection as viewed in FIG. 2 tending to turn it to the dotted line position there shown. p
The latch 46 comprises a pair of plates 62 and 64 pivoted to a mounting block 66 carried by the suspension arm by horizontal pivot pin 68. Pin 68 is parallel to the plane of the door and hence is at right angles to the pivot pin 56 which mounts the suspension arm. The latch also includes the locking arm 70 secured to the plates 62, 64, which has a transverse open notch 72. The notch normally loosely or. freely receives the flange 24 of guide angle 20. 1 I
The detent 48 is rigidly mounted upon the door and has a vertical plate 74 provided with a recess 76 forming a hook'78 which is adapted to overlie an edge portion of the locking arm 70 of latch 46 to hold the latch normally in its retracted or inoperative position in which it extends substantially horizontally as viewed in FIGS. 2 and 4 and in solid lines in FIG. 3 so as to freely move along the flange 24 ofguide angle 20 without binding.
A tension coil spring 80 connected at one end to a bracket 81 on plate 64 of the latch 46 and a bracket 82 on the suspension arm 50 applies a constant upward tension on the latch 46 tending to move it to the dotted line position of FIG. 3 in which position the notch 72 binds upon and locks with the flange 24 of the guide angle 20 to prevent accidental descent of the door. v
.During normal door operation, the door is of course raised and lowered by the cables 32, 34, and the tension in the cables is sufficient to maintain the suspension arms 50 in the vertical positionshown in FIG. 2 against the tension of spring 58. It will be noted that the point of the pivot mounting 56 for the suspension arm 50 is offset to one side of the suspension arm so that the moment of force or torque applied thereto by the tension of cable 32 is sufficient to prevent the suspension arm from being turned away from the vertical by the action of spring 58. In this normal vertical position of the suspension arm, the latch 46 is locked under the hook 78 of the detent 48 so that it is held in the substantially horizontal position in which it moves freely along the flange 24 of guide angle 20 without binding. In this respect it will be noted that there is significantly more play between the notch 72 and the flange 24 of guide angle 20 than between the door and the two guide angle flanges 22 and 24 so that, the guiding of the door being more restricted, the latch structure will not accidentally. bind and interfere with the normal door movement.
In the event of a break in the cable 32 or other failure thereof resulting in a loss of cable tension, spring 58 will turn suspension arm 50 to the dotted line position of FIG. 2 withdrawing latch 46 from the hook 78 of detent 48 and permitting the latch 46 to turn clockwise to the dotted line position in FIG. 3 in which the sides of the notch 72 bind upon the flange 24 of guide angle 20 to lock the door against accidental descent. The door is thus held against dropping in the event of a failure of either one of the cables.
The pivoting of the suspension arm 50 to the dotted line position ofFlG. 2 moves the throat of the notch 72 of the latch in upon the flange 24, that is to the left in FIG. 4, so that in the event of a cable break the notch will not withdraw from the flange as might happen were the latch not mounted on a pivoted suspension am in the manner shown and were the door to cock substantially upon the failure of one of the cables. Such cocking of the door when one cable fails is not unusual particularly when the door is mounted with excessive looseness or play in the jamb assemblies.
The safety latch structure of this invention will be functional if one cable only should fail, as heretofore described, and obviously if both cables should simultaneously fail then both latch structures will be rendered operative. Simultaneous failure of both cables is a possibility particularly where the two cables are extensions of the same continuous member which for example may be connected by a U-bolt to the counterweight. The continuous cable member might thus break where it is connected to the counterweight.
This particular latch structure may be incorporated into a new door assembly and may also be applied to an existing door without any modification of the jamb assembly. It is only necessary to mount the latch assembly on the door in proper relation to one of the existing guide angles. No modification of the guide angle such, for example, as punching or notching is required.
The tension spring 58 for releasing the suspension arm upon the failure of the cable is a spring of substantial strength having sufficient force to operate the latch assembly when necessary with a sharp and immediate, positive response. Sometimes a long interval of trouble-free operation precedes the failure of a cable, and the spring 58 must be strong enough to operate the latch assembly even though the parts may have rusted somewhat or have been painted over. The lateral offset of pivot 56 from the line of cable 32 is desired in order to apply a sufficient torque turning moment on the suspension arm to hold it in the vertical or cocked position of H6. 2 against the tension of spring 58 even though the tension in the cable may slacken somewhat during operation as when the door might stick or not slide freely during downward movement.
1. Safety means for a door guided for movement between upper and lower positions having cable means including at least one cable sustaining the weight of the door and thereby held in tension and operating means connected to said cable means for raising and lowering the door, said safety means comprising an elongated flange adjacent the door extending in the direction of door movement, latch structure comprising a suspension arm pivoted to the door,'a latch pivoted on said suspension arm and having a notch receiving said flange, said latch being movable from a retracted, inoperative position in which said notch freely receives said flange without binding during door movement to an operative position in which said notch binds upon said flange to lock the door against downward movement, retracting means comprising a detent for engaging and blocking movement of said latch from operative to inoperative position, said cable being connected to said suspension arm and the tension thereof holding said suspension arm in position to retain aid latch engaged by said detent, and means responsive to the failure of said cable for moving said suspension arm away from said position retaining said latch by said detent so as to release said latch and for moving said latch to its operative position.
2. The safety means defined in claim 1, wherein said lastmentioned means includes a spring acting on said suspension arm to move it to a position withdrawing said latch from engagement by said detent.
3. The safety means defined in claim 2, wherein said lastmentioned means includes a second spring connected to said suspension arm and said latch.
4. The safety means defined in claim 3, wherein said flange and notch extend substantially parallel to the plane of the door, the axis of pivotal movement of said latch extends substantially parallel to the plane of said door, and the axis of pivotal movement of said suspension arm extends transversely of said door.
5. The safety means defined in claim 4, wherein said flange is a part of the means for guiding movement of said door between its upper and lower positions.
6. Safety means for a door guided for movement between upper and lower positions having cable means including at least one cable sustaining the weight of the door and thereby held in tension and operating means connected to said cable means for raising and lowering the door, said safety means comprising an elongated flange adjacent the door extending in the direction of door movement, latch structure comprising a mounting carried by the door for movement between first and second positions, a latch having a notch receiving said flange, said latch being pivoted to said mounting for movement from a retracted position in which said notch freely receives said flange without binding during door movement to a locking position in which said notch binds upon said flange to hold the door against downward movement, said cable being connected to said mounting and the tension thereof holding said mounting in its first position, means responsive to the loss of tension in said cable for moving said mounting to its second position, means operative in said first position of said mounting to hold said latch retracted and in the second position of said mounting to release said latch, and means for moving said latch to its locking position when released.
7. The safety means defined in claim 6, wherein movement of said mounting to its second position moves said latch toward said flange to dispose said flange deeper in the notch of said latch.
8. The safety means defined in claim 6, wherein said latch moving means and said mounting moving means are springs.
9. The safety means defined in claim 8, wherein said mounting is a suspension arm pivoted to the door, and said latch is pivoted to said suspension arm.
10. The safety means defined in claim 9, wherein said notch and flange and the pivot axis of said latch are substantially parallel to one another, and the pivot axis of said suspension arm is transverse thereto.
11. The safety means defined in claim 10, wherein said flange is a part of the means for guiding movement of said door between its upper and lower positions.