US2567044A

US2567044A - Safety latch for elevators

Info

Publication number: US2567044A
Application number: US689496A
Authority: US
Inventors: Wilson William Webster
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-08-09
Filing date: 1946-08-09
Publication date: 1951-09-04
Anticipated expiration: 1968-09-04

Description

Sept. 4, 1951 I w. w. WILSON 2,567,044

SAFETY LATCH FOR ELEVATORS Filed Aug. 9, 1946 2 Sheets-Sheet 1 INVEN TOR. WILL/AM WEBSTER WILSON p 4, 1951 w. w. WILSON 2,567,044

SAFETY LATCH F'OR ELEVATORS Filed Aug. '9, 1946 2 Sheets-Sheet 2 {I 3/. I in Y 32 pl y i 34 ATTORNEY patented Sept. 4, i951 UNITED {STATES PATENT o- I E SAFETY "LATCH FOR ELEVATORS William Webster .Wilson, Los Angeles, Calif. pplication August 9, 1946, Serial No. 689,496

3fllaims. :1 -This inventionrelates t elevators employed in suspending'members such as pipes or tubes in derricks and relates in particular to an improved latch for elevators.

"It-is an object of the invention to provide a center latch elevatorhavinga rugged and effective latch :anda simple lock for preventingina'dvertent opening of the latch. My present-invention is shownjn conjunction with a center latch elevator of the character described in llnited states Patent No. 2,356,805, granted tome Au ust :29, 1944.

;It isian object'of the inventicnto provide a egmbined latch and lock for pi pe elevators hav" ine-ars n e 'n a s o ope ation.

j-Itlis an object of the invention to provide an elevator latch of the character set forth in the preceding 1 paragraph having a latch lever adapted ftoengage alatch lug and a lock lever mountedon the latch lever for engagement with a lock lug, this look lever having a manually n ageable portion .by which the release of the lpckand, the release of thelatch is accomplished.

.A further object vof the invention is to provide in alatch and lock combination of this character a simple cooperation of elements wherein the Wall which supports'the'lock lug serves as a guard for the manually engageablehandle of the'lock lever- Further objects and advantages of the invention willbebrought out in the following part of the specification, wherein reference to specific details of construction are for the purpose of fully disclosing a preferred embodiment of the invention without limiting the scope thereof set forth in 'the appended claims.

"Referring to the drawing, which is for trativejpurposes only,

"Fig. 1 is a planview of a preferred embodiment (if-my invention.

Fig. 2 is a front elevation corresponding to ig. 1.

Fig. 3 is a fragmentary sectional view, taken asindicated 'bythe line 33 of Fig. 2.

Fig. 4 is an enlarged perspective view of the latch lever.

"Fig. '5 is a fragmentary isometric view showing the 'operativerelationship of the latch lever, lock lever and lock lug.

The elevator shown in the drawing comprises apipe encircling structure 9 adapted to be closed illusandlatched around a pipe which is to be sus" pended or lifted. Herein the term pipe is inclusive of any object used'in a well derrick or in a well having a portionadapted to be enga'ged'by the elevator'whereby 'the'li'fting or suspension of such member is accomplished. 'In the form of the invention shown, the-elevatorccmpr-ises two cooperating parts H and I2 hinged together by means of a hinge pin M so 'asto be swingable from open position into the closed position in which the elevator is shown. The-jaws 'H and I"? are formed with inner semi-cylindrical'boresurfaces l5 and I6, defining'an opening'to receive the cylindrical parts, such as a'pipe, which is to be lifted or suspended. The jaws ll andlZ'hav'e respectively first'and'second free'en'dsl'l and i8 which are brought'irlto juxtaposition when the jaws are closedaround a pipe. The'first free'end I! has thereona latch lug '19 having a face or shoulder lying tothe right of' the median plane (1-41 of the elevator and'being disposed on -a plane b-b which-crosses the plane a-a in the mannershown in Fig. 1.

The second free end ['8 has lugs 2|, 22, 23,and

24 projecting therefrom-to support "a hinge pin 25 on a vertical axis which is spaced from the hinge-pin M a greater distance than the center of the face or shoulder 28- ofthe latch'lug l9. A latch lever '26 is swingable 'on the hinge pin 25. This latch'lever 2.6' has vertically spaced horizon ta'l arms 21 and .28, theleftward ends of which swing-upon'the hinge pin 2'5, 'and a vertical bar portion 29'which connects'the rightward ends-of the arms '21 and 28 and provides between the arms 21 and 28 a latching shoulder 38 for engagement with the latching shoulder 23 of the latch lug is. The leftward ends of the arms 2:?

and 28 areconnected' by a vertical bar 3| and, for

rotating the latch lever 26 in counterclockwise direction, a spring 32' is placed around the intermediate'portion-of the pin 25, one end 33 of this sprin 32 engaging a'portion of the body or jaw l2, and the other end 34 ofthe spring 32 engaging the bar 3! iofthe latch lever 26. The spring 32 constantly urges the latch lever 26 into a position wherein the latch face thereof will cooperate with the latch shoulder 20 of the lug Hi when the jaws II and 12 are in closed relation. A projection 34 onthe'lug 23 of the jaw l2 limits the clockwise rotation of the latch lever 26.

As shown in Fig. 4, the latch lever 25'has vertically spaced

lugs

36 and 31 projecting from the frontfac thereof, these lllfs having openings to receive a pin 39 on which a lock lever 18 is swingable. This lock lever 40 is disposed near the rightward end of the latch'lever 2t and upon the front face of the bar 29 thereof.

The lock lever 40- comprises a vertically elongated 'arcuate wall4'l with'upper andlower'ends 3 of

walls

42 and 43 projecting therefrom toward the latch lever 26 to engage the pin 39. These

end walls

42 and 43 are of the shape of circular segments, the radial edges of the top wall 42 being disposed at an angle of substantially 90 degrees and the lower end wall 43 having thereon a lug 44 to engage the bar 29 of the latch lever 26 and thereby limit the counterclockwise rotation of the lock lever by a spring 45 which has its coiled portion surrounding the pin 39, this spring 45 being relatively weaker than the spring 34. The lock lever 46 includes a fiat wall 41 which projects rightwardly from the arcuate wall 4| in substan--' tially parallel relation to the front face of the bar 29 and in spaced relation thereto. This manually engageable portion 41 projects rightwardly beyond the rightward edge of the bar 29 so as to constitute a manually engageable handle which may be pulled forwardly as indicated by the arrow 48 of Fig. 3. A locking shoulder 50 of the upper end wall 42 and that portion of the arcuate wall 4| adjacent thereto comprises a latch dog or shoulder proper for engaging a lock lug 5| formed on a wall 52 which projects from the .jaw member ll above the handle portion 41 of the lock lever 40 so as to serve as a guard for the handle portion 41 of the lock lever 40', as well as for supporting the lock lug 5|.

From an inspection of Fig. 1, it will beperceived that the latch lever 26 swings around a hinge pin 25 which is disposed with its axis at a greater distance from the axis of the hinge pin 14 than is the center of the face 20 of the latch lug l9. It is characteristic of this arrangement of latch lever 26 and latch lug l9 that forces applied to the jaws II and I2 tending to separate them will produce forces in the latch lever 26 and latch lug l9 tending to prevent their disengagement. As an additional precaution against the latch lever 26 being inadvertently rotated in clockwise direction around the hinge pin 25 so as to move the rightward portion ofv the latch lever 25 out of engagement with the latch lug I9, the lock lever 49 and the lock lug 5| are provided.

When the latch mechanism is in operative condition, as shown in Fig. 1, the engagement of the lock lever 40 with the lock lug 5| prevents clockwise rotation of the latch lever 26. However, the lock lever 46 is so arranged with relation to the latch lever 26 that a single manual. operation will accomplish release of the lock lever 48 from engagement with the lock lug 5| and clockwise rotation of the latch lever 26 so as to swing the same out of engagement with the latch lug l9. The workman, desiring to release the latch mechanism and open the elevator, reaches under the guard wall 52 and pulls the lever portion 41 of the lock lever 46 toward him. The force thereby applied to the lock lever 46 rotates the same in clockwise direction, against the force of the spring 45, into the position indicated by dotted lines 45a wherein the leftward edge of the arcuate wall 4! engages the front face of the latch lever 26 and the locking shoulder 59 of the lock lever 43 is moved leftwardly out of engagement with the lock lug 5|. Thereafter, the pull which the workman exerts on the handle portion 4'! of the lock lever 40 acts upon the latch lever 26 to swing the same in clockwise direction, thereby carrying the latching face 36 of the bar 29 out of engagement with the latching face 20 of the latch lug l9, whereupon the jaws and i2 of the elevator will swing open.

When the elevator is in open position, counterclockwise rotation of the latch lever 26 is limited by a shoulder 58 of the jaw l2, so that the latch lever 26 is maintained in position for reengagement with the latch lug I9 when the elevator jaws i l and I2 are again swung into closed relation. The swinging of the jaws II and I2 is accomplished by use of handles 60 and BI which project forwardly from the jaws II and I2 and have

knobs

62 and 63 thereon for manual engagement. The reengagement of the parts of the latch mechanism is accomplished merely by moving the jaws II and 12 into closed relation, for the reason that the latch lug I9 and the bar 29 of the latch lever 25 have respectively angularly disposed

faces

64 and 65 so that the bar 29 will ride over the lug l9 and then drop into latching position, whereupon the locking shoulder 59 of the lock lug 40 will move behind the lock lug 5 l One of the features of the latch and lock arrangement of the invention arises from the fact that the lock lever 40 projects forwardly from the latch lever, so that the latch lever 26 and the lock lever 4!) define vertical planes which cross each other at, an angle of substantially This gives a cooperation of parts in the structure wherein inertia or momentum acting in the structure in a direction-to cause release of the latch lever 26 will not produce a release of the lock lever 49, and inertia or momentum acting in the structure in a direction to cause release of the lock lever 49 will not have such direction as to cause release of the latch lever 26. In explanation of this, let it be presumed that inertia is acting forwardly or along the line a-a from the hinge pin 14 through the latch lever 26. This exertion of the force of inertia in the latch lever 26 will tend to swing it in clockwise direction, but the same inertia acting in the lock lever 49 will tend to hold it in locked position or at least will not move the lock lever 46 out of its locked position. Likewise, inertia acting leftwardly through the'center of gravity of the lock lever 46 so as to tend to swing the same in clockwise direction and unlock the same, will act longitudinally through the latch lever 26 and therefore will exert substantially no opening force on the latch lever 26.

I claim as my invention:

1. In a latch for an elevator comprising a pipe encircling structure with first and second free ends adapted to be latched together when the structure encircles the pipe, the combination of: a latch lug and a lock lug respectively carried by said first free end, both of said lugs being outwardly spaced from their associated end of the structure, with the lock lug spaced a greater distance than the latch lug; a latch lever hinged on said second free end for engaging said latch lug when said structure encircles said pipe; spring means urging said latch lever intoa position for engagement with said latch lug; a lock lever on the outer face of said latch lever and positioned .so that when said latch lever is in latching engagement with said latch lug, said lock lever will be positioned for locking engagement with said lock lug; means for urging said lock lever into engagement with said lock lug; manually engageable means carried by said lock lever for receiving a force which will swing said lock lever out of engagement with said lock lug" and said latch lever out of engagement with said latch lug; and a wall extending from said first free end in a position to guard said manually engageable means. 7

2. In a latch for an elevator comprising a pipe latch lever pivotally carried by the other of said free ends for latchingly engaging the latch lug, when said structure encircles said pipe; means resiliently urging said latch lever toward latching position; a fixed separate lock lug carried by said one of said free ends positioned outwardly of said latch lug and beyond the latched position of said latch lever; a pivotally mounted "lock lever carried by said latch lever adjacent its free end: means resiliently urging said lock lever to a locking position between the lock lug {and the latch lever upon movement of the latter to latched position, whereby forces tending to niove'the latch lever from latched position act to put the lock lever in compression; and manually operable means for actuating said lock lever to release position.

3. In a latch for an elevator comprising a pipe encircling structure with first and second free ends adapted to be latched together when the structure encircles the pipe, the combination of: a latch lug carried by one of said free ends; a latch lever pivotally carried by the other of said free ends for latchingly engaging the latch lug, when said structure encircles said pipe;

means resiliently urging said latch lever toward 3 latching position; a fixed separate lock lug carried by said one of said free ends positioned outwardly of said latch lug and beyond the latched position of said latch lever; a lock lever having an elongate portion spanning the free end of said latch lever and terminating in laterally projecting end lugs; means pivotally connecting said end lugs to adjacent parts of the latch lever for pivotal swinging movement; means resiliently urging said lock lever to a locking position between the lock lug and the latch lever upon movement of the latter to latched position, whereby forces tending to move the latch lever from latched position act to put the lock lever in compression; and a hand grip projection extending from the elongate portion of the lock lever in substantially parallel relation to the front face of the latch lever, inwardly of the outer end of said lock lug, for swinging said lock lever to release position.

WILLIAM WEBSTER WILSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,067,663 Grau Jan. 12, 1937 2,108,238 Strelow Feb. 15, 1938 2,356,805 Wilson Aug. 29, 1944