US2671531A - Elevator door safety lock - Google Patents

Description

March 1954 M. c. HOLMSTROM 71,531

ELEVATOR DOOR SAFETY LOCK Filed May 16, 1952 2 Sheets-Sheet l g I 6, 5 k Z g E E 47 R E :1 56? 1: 53 z i 35 1554 6.0; 4D 0 Q Z9 P Z 50 ,29

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F "iVVENTbR 15 Z 7 Z4 Maw/f2 o/mszram ATTORNEY March 9, 1954 M. c. HOLMSTROM 2,671,531

ELEVATOR DOOR SAFETY LOCK Filed May 16, 1952 2 Sheets-Sheet 2 i a 30 20 INVENTOR 1 J' Maurvzz C. fio/mszr'om 4 d F. 7 mamm' Patented Mar. 9, 1954 UNITED STATES PATENT OFFICE ELEVATOR DOOR SAFETY LOCK Mauritz O. Hohnstrom, St. Paul, Minn.

Application May 16, 1952, Serial No. 288,163

12 Claims. 1

This invention relates to an improvement in an elevator door safety lock and deals particularly with a lock for-an elevator of the type employing vertically slidable doors.

Various types of safety locks have been employed for use onelevators of the type most commonly used as freight elevators. These safety locks are designed to prevent opening of the elevator doors at any time except when the elevator is level with that particular door opening. In view of the fact that it is sometimes desirable to be able to open the doors when the elevator is not level with the floor, the persons using the elevator remove these safety looks or render them useless. The present device is designed to render locks of this type more foolproof and to prevent those using the elevator from tampering with the safety devices and destroying their usefulness.

A feature of the present invention resides in the provision of an elevator lock employing an elongated rod fastened for movement with one of the doors and extending through the housing of the look. When this rod is in place the door can not be opened unless the elevator is level with the door opening. If the rod is removed the elevator circuit is broken so that theelevator can not be used. As a result the device is relatively fool-proof and can not readily be rendered useless without considerable difficulty.

A further feature of the present invention resides in the provision of an elevator. safety lock which is provided with a locking arm provided with a grooved end. This grooved end is designed toaccommodate an end of the latch bar of the elevator door. When the latch bar is in latching position the locking arm is pivoted in a manner to close a circuit switch so that the elevator may be operated. When the locking arm is in this position the latch bar is held from vertical movement. As a result the door can not be opened while the circuit to the elevator is closed.

A further feature of the present invention lies in the provision of a means for holding the looking arm in circuit breaking position. As the elevator door is opened a rod secured to the door enters the groove of the locking arm and prevents this locking arm from pivoting into position to close the elevator circuit. Thus the operator of the elevator can not render the elevator operative while the door is open by'manually swinging the locking arm into circuit closing position and wedging the arm in this position to hold the circuit closed.

.An important feature of the present invention liesin the provision of a means for holding the locking arm in circuit breaking position while the elevator door is open and in providing an additional means for breaking the circuit in the event the locking arm holding device is removed. If the member which enters the groove of the locking arm to hold it in circuit breaking position is detached and removed, an additional circuit breaking switch is actuated to break the elevator circuit.

These and other objects and novel features of the present invention will be more clearly and fully set forth in the following specification and claims.

In the drawings forming a part of the specification:

Figure 1 is an elevation view of a portion of a pair of vertically slidable elevator doors, the elevator door frame, and the safety lock mechanism.

Figure 2 is a sectional view through a portion of the elevator door and frame, the position of the section being indicated by the line 2--2 of Figure 1. 1

Figure 3 is a perspective view of the lock housing, the operating mechanism having been removed therefrom.

Figure 4 is a sectional view through the safety lock, the position of the section being indicated by the line. 4-4 of Figure 1.

Figure 5 is an elevation view of the safety lock mechanism, the housing cover plate having been removed.

Figure 6 is a sectional view similar to Figure 4 showing the lock in a different position.

Figure 7 is an elevation view of the lock with the housing cover removed, showing a modified form of construction.

Figure 8 is a sectional view through the apparatus, the position of the section being indicated by the line 88 of Figure 5.

The elevator door lock includes a supporting housing which is indicated in general by the numeral II}. This housing 10 is secured by bolts or other suitable means to the door guides H which guide the elevator doors in their vertical movement. Alternatively the housing l0 could be mounted upon the shaft wall I2 forming a part of the door frame, or in any other suitable manner.

The elevator door opening is normally closed by a pair of vertically slidable doors I3 and M which slide in the guides ll. Each door is substantially half the height of the door opening so as to close the opening when the upper door [3 ,is lowered and the lower door [4 is raised. Means are provided, not illustrated, for connecting the doors I3 and I4 so that the doors will open and close in unison. Such arrangements are conventional in the art.

As illustrated in Figure 2 of the drawings, the guides H are provided with an inwardly facing channel l5 which is designed to accommodate an outwardly turned flange l6 of an angle member I! mounted at the side edge of each door. The channel l5 slidably supports the flange It to permit free vertical movement of the doors.

In order to hold the doors closed, a pair of latch bars I9 are provided, one of which is illustrated in the drawings. In usual types of construction the two latch bars are connected to a lever which moves both latch bars into projected or retracted position simultaneously. When the latch bars I9 are projected laterally a right angularly extending extremity engages over a wedge shaped lug 2| on the casing Hi to hold the door M from lowering. When the projecting end 20 of the latch bar I9 is in the position illustrated in Figure 5 of the drawings, this extremity 20 will strike the upperend of the lug 2| upon slight downward movement of the door l4, the lug arresting further movement of the door.

7 It is usual practice to provide a member such as the lug 2| at each side of the door opening so that each of the two latch bars l9 engages a corresponding shoulder and locks the door [4 from opening. Obviously the safety look A may be used on either. or both sides of the door opening. In the event the safety lock is mounted on the opposite side of the door opening from that illustrated in the drawings, the parts are correspondingly reversed.

The housing I0 is illustrated in Figure 3 of the drawings, the operating parts of the mechanism being omitted. As illustrated in Figure 3, the housing body includes a backing plate 22 from whichprojects a substantially L-shaped wall 23. The outer side of the housing is provided with an elongated vertically extending chamber 24 from which the wedge shaped projection 2| extends. A short partition wall 25 separates the. elongated chamber 24 from the shorter chamber 26. An elongated tubular housing 21 is secured to the upper wall 29 of the housing, the tubular enclosure being illustrated in Figures 1, 4 and 5 of the drawings.

A locking. arm 30 is pivotally supported at 3| to the base wall 22 of the housing I0. This locking arm 3|] is of sufficient length to extend into close proximity with the-upper extremity of the wedge shaped lug 2|. The lower wall 32 of the shorter chamber 26 is apertured at 33 so that the locking arm 30 may extend through this wall 32. The upper end of the adjoining wall 34 of the longer chamber 24 is also apertured at 35 to accommodate a lateral extension 36 on the locking arm 33 and integral therewith.

The locking'arm 30 is provided with a forwardly extending enlargement 31 which is slotted or bifurcated as indicated at 39. The slot walls are preferably curved so that the locking arm 30 may pivot within pretermined limits while still accommodating the angularly turned extremity 20 of the latch bar IS. The lateral extension 33 is apertured as indicated at 40 for a purpose which will be later described in detail.

A lever arm 4| is pivotally supported in the elongated chamber 24 of the housing I0 by means ofa pivot 42 which extends through the outer wall 43. of the chamber 24 and through the partition wall 25. This leverv arm 4| is pivotally connected at 43 to a lever arm continuation 44 which is bifurcated at its outer end 45 to support a roller 46. A pivot 41 extends through the bifurcated ends of the extension 44 to rotatably support the roller 45. The pivot 43 is only employed for providing an initial adjustment of the angularity between the lever 4| and the extension 44. Once the position of the extension 44 relative to the lever 4| is determined a pin or key 49 may extend through the lever and the extension to hold these elements from relative pivotal movement. In other words, once the adjustment between these parts is made, the lever 4| and its extension 44 form an integral unit.

A latch bolt 50 is slidably supported by the housing |0for movement toward or away from the base wall 22. Guides 5| illustrated in Figure 3 of the drawings guide the latch bolt in its sliding movement. The latch bolt 50 is provided with a bifurcated end 53 which is pivotally connected at 54 to the lever 4|.. Sufficient play'is provided between the latch bolt and the lever to compensate for the varying angularity between these parts.

The latch bolt 50 is of proper proportions to extend into the aperture 40 on the locking arm 34.- Thus when the lever 4| is in the position illustrated in Figure 4 of the drawingsthe latch bolt extends into the lockingarm 30 and holds this locking arm from pivotalmovement. The lever 4| is actuated by a cam such as the cam 55 in Figure 6 of the drawings. When the roller 46 engages the cam 55, the lever 4| is pivoted in a counter-clockwise direction as viewed in Figures 4 and 6. When thus pivoted, the latch bolt 50 is withdrawn from the aperture 40 of the locking arm 30. so that the locking arm is free to pivot.

A spring 55 is interposed between the lever 4| and the base plate 22 of the. housing l0 so as to normally urge the latch bolt 50 into the locking arm aperture 40. The spring 55 also tends to. urge the roller 46 into position for engagement" with a cam such as 55.

The upper wall 29 and lower. wall. 32 .of. the

smaller chamber 26 are provided with. key hole shaped apertures 51 and 59 respectively. These apertures are substantially axially aligned with the tubular enclosure 2T mounted upon the upper wall 29 of thehousing: An elongated rod' 50' havinga radially extending fin or flange: 3| thereupon is slidably supported by. the openings .51 and 59.

30 can not rotate.

A bracket 54'is secured to the lower door I4 and is provided with a bearing 55"at its' outer extremity through which the rod 50 extends:

The lower end of therod 60 is threaded to accomin retracted position.

A switch 56-is mounted'upon the partition wall 25. of the housing l0 and includes an. operating The upper extremity of the rod 50 is provided with a disc shaped flange 52 which forms a bearing for the upper end of the rodlil-w within the tubular enclosure 21' and which prevents the rod from being pulled downwardly out ofthe housing. The flange or fin 5| terminates at 63 in spaced relation to the lower end ofthe" rod 50. However, the proportions are such that the pin or flange 6| is at all times engaged in at least one of the openings 51 or 59-50 that therod provides a safety switch which is designed to .break the circuit to the elevator motor or control in the event the safety switch is tampered with and the housing 2'! and its enclosed rod 6| are detached.

-- A switch 69 is mounted upon the outer housing wall 43 and includes a switch actuating plunger 19 which is resiliently urged against a plunger actuating bracket 1| on the locking arm30. The

switch 69 is of the normally open type, but in practice the switch is normally held closedby the engagement of the plunger operating bracket 1| with the switch plunger 10. In other words, when the locking arm 30 is in the position shown in Figure the switch 69 is closed. However,

as soon as the locking arm 30 pivots into position to open the elevator doors, the switch 10 is opened and the circuit to the elevator motors or control is broken.

The operation of the safety switch is as follows: As the elevator car moves into alignment with the door opening, a cam 55 engages the roller 46 which pivots the lever 4| from the position shown in Figure 4 of the drawings to the position shown in Figure 6. This action withdraws the latch bolt 50 from the aperture 40 of the locking arm 30. However, the locking arm 3|] remains in looking position unless the latch bar |9 is manually operated. I

When the latch bar l9 is pulledinto retracted position, moving the latch bar to the right from the position shown in Figure 5 to the position shown in Figure 7, the locking arm 30 pivots in a counter-clockwise direction. A spring 12 normally biases the locking arm 30 toward the position shown in Figure 7. Upon moving the latch bar l9 into retracted position the angularly extending end 2|! of the bar is moved out of alignment with the wedge shaped lug 2| so that the door l4 may be lowered and the upper door I3 simultaneously raised.

As the door |4 lowers the bracket 64 moves downwardly with the door, drawing the flanged rod 60 downwardly. The flange 6| of the rod 60 enters the slot 3| of the locking arm and holds this locking arm from pivotal movement. The lower end 63 of the fin or flange BI is spaced closely above the off-set end 20 of the latch so that as soon as the latch end 20 leaves the slot 39 the fin 6| enters the slot and holds the locking arm 30 from pivotal movement. As long as the locking arm 30 is held in the position shown in Figure 7, the contacts of the switch 69 are open and the elevator cannot be moved.

Upon the closing of the doors l3 and M, the rod 60 is raised until it is withdrawn from the slot 39 just as the off-set end 20 of the latch bar |9 enters the slot. When the doors are fully closed the latch bar I9 is moved laterally into locking position as shown in Figure 5, this action pivoting the locking arm 30 in a counter-clockwise direction. The control to the elevator motor is then in circuit and the switch contacts of switch 69 are closed.

As soon as the elevator car is moved sufiiciently to disengage the roller 46 from the cam 55 the latch bolt 50 is engaged in the locking arm to hold the locking arm from pivotal movement. In the event the elevator passes a door opening, the lever 4| merely unlatches the locking arm tem- 6 porarily, but relatches the same as soon as the door opening is past.

The foregoing description applies to a con struction not employing a movable cam. In some installations, the cam 55 is movable in the shaft, and only projects into the path of the cam roller 46 when a selected floor is reached.

For installations of this type, the lever 4| is extended substantially beneath the latch bolt 50, while for fixed cam arrangements the lever 4| may be cut off just below the latch bolt 50. A switch I5 is mounted in the elongated chamber 24, and is provided with a plunger 16 in the path of movement of the lever 4|. When the .cam roller is out of engagement with the movable cam 55, the lever 4| is in the position shown in Figure 4 and the switch to the elevator controls or motor is closed. When the cam 55 engages the roller 46, the lever arm 4| is pivoted into the position shown in Figure 6. In this position the latch bolt 59 is unlatched, and the switch contacts of switch 15 are opened, thus preventing operation of the elevator.

A circuit diagram has not been shown in view of the simplicity of the circuit, and further due to the fact that the circuits may be arranged di-. rectly in the elevator motor circuit or may act through suitable relays. In the fixed cam structure, the switches 66 and 69 may be in series so that when either is opened, the elevator cannot operate. When a movable cam arrangement is provided, the third switch 15 may also be in series with the switches 66 and 69, and the circuit to the elevator may be broken when any of the three switches is opened.

In accordance with the patent statutes, I have described the principles of construction and operation of my elevator door safety lock, and while I have endeavored to set forth the best embodiments thereof, I desire to have it understood that obvious changes may be made within the scope of the following claims without departing from the spirit of my invention.

I claim:

1. A safety lock for vertically movable elevator doors having a laterally slidable latch bar having an angular extremity, the lock including a support, a locking arm pivotally supported by said support, a vertically grooved end in said locking bar designed to accommodate the angular extremity of said latch bar, a fixed projection engageable beneath the extremity of said latch bar in latched position thereof, a lever arm pivotally supported by said support, a roller supported by one end of said lever arm, and a latch bolt connected to the other end of said lever arm, said latch bolt being engageable with said looking arm in latched position thereof for holding said locking arm from pivotal movement and holding said latch bar in latched position from lateral movement.

2. A safety lock for elevators having vertically movable elevator doors and laterally movable latch bars thereupon, the lock including a support, a locking arm pivotally supported by said support, means on the free end of said locking arm designed to accommodate the extremity of said latch bar and to be pivoted thereby, said latch bar being movable between two extreme positions, said bar extremity acting to pivot said locking arm between two extreme positions, a locking member engageable with said latch bar extremity in one extreme position of said latch bar to hold said latch bar from vertical movement, a lever pivotallly secured to said housing,

means or pivotmg seid -lever, a liatch tort connected to said lever for aotuaition thereby, said latch bolt in *one extreme position engaging said locking arm when said locking "arm and said latch bar are sa'id one extreme position.

3. The structure described :in them 32 and including means rnovezble with theelevator door for holding :said locking arm in said other extreme (position when said door" is at ileast partially open.

45The structure described in claim 2 and Ancluding a member fslidaibly supported by said housing and connected to the elevator door for moeemmt'merewith, .said member engaging said docking arm in its other extreme position and holding said locking from movement toward said extreme position.

:5. lThe structure described in claim 12 and :in- :a control :switch :actuated *by :said locksing arm.

i6. elevator safety lock 'for use in conjunction with elevatorshaving'verticallylmovable elevator doors and laterally movable latch barspthe lock including a supportpaslocking arm movably supported "upon said :support tor movement between two extreme xpo'sitions, said locking arm having (a grooved :portion designed "to Iaccommodate the extremity .of "the latch :bar, the latch bar beings-movable rbetweenitw'o extreme positions to move the locking arm together therewith, :an elongated :slidable :memher secured :to the door tor movement :in unison therewith, said sli'dabl'e member being supported iby said support, "means on said slidahle :meniber engageable in said notchedportionnf'saidilockingnrm:uponropening movement of the door for holding said locking 35 Number arm in one :extreme 'position, imeans efor holding said extremity of the eaten :bar :from *vertical movement when said docking varm is in its other extreme t position, and switch means on said :sup-

5 said support.

8. The structure described in claim i6 and mcIuding switch means engageable with said s'lidfable means and actuated hy disengagement ofisaid slidable means from said support.

10 9. The structure described in claim *6 end 11neluding to lever pivotally supplanted to said support,:.a latch bolt movable into rand out 01 en- 'ga-gement with locking arm and icon d to said lever foraactuationvthereby.

.15 10. The structure described :in claim 6 and in- "cluding a cam lever :pivotally supported :by said support, a latch holtsupported :by said support: and .engagea'bl'eland "disengageable with ssiid l'ookingarm, and actuated byLsaid icam 'lever.

r v0 11. The structure described in claims and in eluding a lever pivotally'secm'ed to said suppoz t, a cam roller secured to :said "lever for actuwting the same, and a switch actuated never.

12. The structure described in claim :6 and m- 25 eluding :a lever pivotally secured to said housing,

a latch 'bolt engageable and :disengageahlewith saidlocking arm,'means connectingisaid latch bolt and said lever for actuationiinzunison,assecomi switch means, and means conimi'dllever dm' -adtu '30 ating said switch means.

References Cited in the file of this patent UNITED STATES PATENTS

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