US 3431011 A
Description (OCR text may contain errors)
March 4, 1969 MARTIN ET AL RELEASABLE LUMBER 5mm; manor:
Filed March 2, 1967 uvvavrops: JOHN 1.. MARTIN WARREN H. BOWER ROBERT J. MucKEY 611M: a 914W FIG. 4
A TTORNEVS United States Patent 6 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to a lumber sling device which may be actuated from a remote distance to release the sling from its load. The device includes a frame means defining a rectangular shape such that one end of a lumber sling can be secured to one side of the rectangular shape and the sling then passed around a load to be carried with a portion extending up through the rectangular shape to bear against the opposite side. The portion of the sling extending up through the rectangular shape connects to a hoisting mechanism such as a crane. Another side of the rectangular shape constitutes a latch mechanism connected to a control line such as a string or cord which dangles down from the latch mechanism. The arrangement is such that when a load of lumber is carried to an elevated level and set in a desired position such that the load on the sling is relieved, an operator from a remote location such as below the lumber or on the ground, can pull the line which will operate the latch mechanism and open up the rectangular shape in such a manner that the sling may be pulled free of the load without the necessity of an operator manually removing the sling.
This invention relates to a releasable device enabling a sling carrying a load of lumber to be released from the load from a remote location after the load has been set in a given position.
In building construction work, there are many instances in which it is necessary to transport a load to an elevated position. For example, in roofing operations, after a skeletal frame has been erected, a crane or other hoisting mechanism is employed to lift lumber, such as cross beams and the like, to the roof area. Toward this end, a sling such as a fabric cloth or belt of substantial width is wrapped about the lumber and hoisted by the crane or other mechanism to the roof area.
After the lumber has been set in position, it is necessary for a worker to walk to the sling and release it so that the sling is free to be used to pick up another load, In this respect, the worker usually has to walk along high beams to reach the load with the result that many accidents have occurred.
With the foregoing in mind, it is a primary object of this invention to provide a releasable lumber sling device wherein loads such as lumber may be raised to an elevated position and the carrying sling released from the load without the necessity of any worker or other persons actually having to be physically present at the sling to release the same, all to the end that greater safety during construction operations is realized.
More particularly, it is an object to provide a releasable sling device so designed that release thereof cannot be elfected until the load on the sling has been relieved; that is, after the lumber has been positioned in a safe place such that there is no risk of the sling inadvertently opening and dropping the lumber.
Other objects of this invention are to provide a simple mechanical device which may be readily secured to conventional slings for enabling release of the sling from a 3,43 1,01 l Patented Mar. 4, 1969 remote location, the device itself being rugged and simple in design, economical to manufacture, and easy to use.
Briefly, these and other objects and advantages of this invention are attained by providing a frame structure generally of rectangular configuration arranged to have one side secured to the end of a sling and another portion of the sling, after wrapping about a load such as lumber, passed through the rectangular opening to define a loop. When the load is supported by the sling, pressure is brought to bear against the side of the rectangular configuration opposite that side to which the end of the sling is connected. One of the sides of the rectangular frame constitutes a latch mechanism. A control line in turn is connected to this latch mechanism and is of sufiicient length to dangle from the device such that it may be actuated by a person on a lower level or at a remote location. Pulling on this control line will release the sling by opening up the rectangular configuration. This operation can only be effected, however, after the load on the device is relieved and thus it is not possible to open the device until the load or lumber as the case may be has been properly set in a desired location.
A better understanding of the invention will be had by now referring to a preferred embodiment thereof as illustrated in the accompanying drawings, in which:
FIGURE 1 is a fragmentary perspective view of the releasable lumber sling device in use during a construction operation;
FIGURE 2 is a front elevational view of the device in its locked position;
FIGURE 3 is a side elevational view of the device of FIGURE 2; and,
FIGURE 4 is a front elevational view similar to FIG- URE 2 but illustrating the position of various components of the device immediately after releasing of the device.
Referring first to FIGURE 1, there is shown a load such as a wooden beam 10 in the process of being hoisted by a sling 11 for positioning at an elevated location such as across the ledges 12 and 13 of a construction.
Heretofore, after such a beam had been positioned, it was necessary for a worker to walk along the beam to the sling 11 and manually release or untie the sling from the lumber. Walking across such beams particularly at great heights, is a hazard to the Worker as well as a time consuming operation.
In accord with the present invention, the sling 11 is secured to the beam 10 by means of the releasable sling device of this invention. This device is designated generally by the numeral 14 and includes an L-shaped frame 15. The extreme end of the sling 11 is secured about the leg of the L as indicated at 16. The upper end of the arm of the L serves to pivot at 17 a holding member 18 extending generally parallel to the leg of the L. The sling 11 wraps about the load or beam 10 and then passes up through the generally rectangular shape defined by the holding member 18 and L-shaped member 15 as indicated at 19. It will be evident that with this arrangement, there will be an outward pressure against the holding member 18 by the sling 19 under load.
The structure is completed by a latch mechanism designated generally by the numeral 20 extending across the side of the rectangular shape opposite the arm of the L-shaped member 15. Cooperating with this latch mechanism is a control line 21 which may constitute a cord or string connected to the latch mechanism and dangling downwardly as indicated. The arrangement is such that a pull on the line 21 after the beam 10 has been properly positioned by the sling and the load on the sling relieved, will serve to release the holding member 18 so that the same may pivot about the pivot 17 and thus open up the rectangular shape to release the entire sling.
The foregoing operation will be better understood by now referring to the enlarged front view of the frame structure and latch mechanism as illustrated in FIG- URE 2. As shown in FIGURE 2, the leg of the L-shaped portion is designated 22 and terminates in a reduced width portion 23. A coupling or stop-bolt 24 is secured into the lower end of the reduced width portion 23, the purpose for which will become clearer as the description proceeds.
The arm of the L-shaped frame portion 15 is shown at 25 and is bifurcated at its upper end for pivoting engagement of the holding member 18 as described in conjunction with FIGURE 1.
The free end of the holding member 18 includes a notch 26 and an extended portion defining a cradling area 27 and a sloping surface 28. This structure cooperates With a latch plate 29 including a lower window opening 30 receiving the reduced width portion 23 of the leg 22. The bolt 24 serves as a stop to prevent the plate 29 from being removed from the reduced width portion 23 and yet provides a fairly loose coupling.
The upper end of the latch plate 29 includes a window opening 31 receiving the free end portion of the holding member 18. The arrangement is such that the upper portion of the window overlies the holding member and is received within the notch 26 as illustrated.
The latch mechanism also includes a support 32 pivoting a latch lever 33 at one end as indicated at 34. The other end of the latch lever includes an overlying portion in the form of a pin 35 received within the cradling area 27 of the extended portion for the holding member 18.
The foregoing construction will be better understood by referring to FIGURE 3 wherein it will be noted that the latch lever 33 includes a bifurcated structure in the form of upperly extending arms 36 and 37 receiving the pin 35 and trunion portions 38 and 29 supporting the pivot pin 34 to the pivot support 32.
It will be evident, referring once again to FIGURE 2, that the latch lever 33 is mounted for a pivoting movement about the pivot 34 in a clockwise direction from a position generally parallel to the latch plate 29 to an angulated position. The arcuate extent of pivoting movement is limited by a stop means in the form of a bolt 40 threaded into the plate 29 and including a biasing spring 41. The spring 41 bears against the latch lever 33 adjacent the peripheral portion of a central window opening 42 through which the shaft of the bolt passes. By this arrangement, the head of the bolt 40 serves as a stop to limit pivoted arcuate movement of the latch lever 33 relative to the latch plate and also functions to provide a biasing means for urging the latch lever 33 to its upright or generally parallel position relative to the latch plate 29.
The control line 21 is connected to the latch lever 33 through the medium of an extending arm 43 rigidly secured to the lever 33.
FIGURE 4 illustrates the latch mechanism in released condition wherein a pull has been exerted on the control line 21. As shown, both the overlying pin 35 of the latch lever and the overlying portion of the latch plate 29 have been pulled free of the end portion of the holding member 18 so that in the position illustrated in FIGURE 4, this holding member 18 is free to swing about the pivot point 17 in a counterclockwise direction to open up the rectangular configuration.
The overall operation of the device will now be described. Initially, the end of the sling 11 of FIGURE 1 will be secured about the lower leg 22 of the frame and theportion 19 of the sling, after being wrapped about lumber, passed into the rectangular configuration by pivoting the holding member 18 upwardly from its position shown in FIGURE 4. This member is then swung downwardly and latched manually by the latch plate and latch lever. The sling is not shown in FIGURES 2 and 4 but when the device is in its closed position as 4 illustrated in FIGURE 2 with the sling attached such as shown in FIGURE 1, it is clear that an upward or outward force will be exerted on the holding member 18 as indicated by the arrow F in FIGURE 2.
As a consequence of this force, the magnitude of which will depend upon the load being carried, the notch 26 of the holding member 18 is urged tightly against the upper portion of the window 31 for the latch plate 29 and because of the notch configuration, it is not possible for the latch plate 29 to free itself from the remaining portion of the frame structure. In addition, the latch lever 33 will be held within the cradled area 27 of the extended portion of the holding member 18 and held there as a consequence of the upward force exerted on the holding member 18. In addition, the biasing spring 41 will tend to hold the latch lever 33 in the position illustrated in FIGURE 2.
With the component parts in the positions illustrated in FIGURE 2, it will be evident that loads may be safely carried by the sling structure as described in FIGURE 1.
After a load has been properly placed in a set position, slack may be provided in the sling which will relieve the force on the holding member 18 in the direction of the arrow F. At this time, a worker at a remote location such as at several levels below the elevated position of the load, may pull on the control line 21. This action will initially pivot the latch lever 33 about the pivot point 34 against the bias of the spring 41 thereby removing the overlying pin 35 from the cradled area 27 and sliding it along the top surface of the extended portion and along the upwardly sloping surface 28. Because of this upwardly sloping surface, the extended portion of the holding member 18 will be cammed downwardly and this camming action will thus remove the notch 26 from engagement with the underside of the Window 31 defined in the latch plate 29.
Continued pulling on the line 21 will cause the latch lever 33 to ride over the sloping end portion 28 to become completely disengaged from the extended portion of the holding member 18. At this point, after becoming free of the holding member 18, the latch lever 33 will engage the head 40 of the stop bolt and further pulling force on the control line 21 will pull the latch plate 29 over the extended portion of the holding member 18. The relative positions of the parts after this operation are as illustrated in FIGURE 4.
With respect to the foregoing, it should be appreciated that the notch 26 is initially removed from the overlying portion of the latch plate 29 as a consequence of the latch lever bearing against the sloping surface 28. Thereafter, continuous pulling on the latch lever pulls the latch plate itself completely over the extended portion of the holding member 18 so that the member 18 is in the free position illustrated in FIGURE 4. This sequence of operations can only take place after the load indicated by the force F in FIGURE 2 is relieved.
With the device as shown in FIGURE 4, it will be evident that the holding member 18 is now free to swing in a counterclockwise direction about the pivot 17 and thus completely release the portion 19 of the sling of FIGURE 1. The operator of the crane supporting the sling can then simply pull the sling free of the load and the mechanism can be used to hoist another load.
It should be noted that the releasing of the sling device has been effected solely through the pulling of the line 21 after the load has been set. This operation, as mentioned, can be accomplished by a worker a considerable distance away so that he necessity of any worker walking out on the beam 10 to release the device is avoided.
The latch lever 33 with the biasing spring 41 in one respect constitutes a trigger mechanism for the removal of the larger latch plate 29 which actually serves to hold the holding member 1 8 in its closed position. In addition, however, the latch lever 33 also constitutes a holding means for the holding member 18 in that the overlying pin will hold the end of the holding member 18 in the same manner as this member is held by the upper end of the latch plate 29. There is thus provided a double protection.
Further, the biasing of the spring 41 together with the upwardly sloping surface 2 8 assures against any accidental removal of the latch lever or inadvertent swinging of the same about its pivot 34 in any manner that might possibly release the holding member 18. Thus a positive pulling on the control line 21 is necessaly to release the structure and as stated, such release can only be effected after the load on the sling device has been relieved. This relief of the load in turn can only result after the load has been properly placed in a set position.
From the foregoing description, it will thus be evident that the present invention has provided a novel releasable lumber sling device wherein all of the various objects set forth heretofore are fully realized.
What is claimed is:
1. A device for releasing a sling from a load, comprising: a frame means defining a generally rectangular shape such that one end of a sling can be secured to one side of said frame and thence passed around a load to be carried and extended up through said rectangular shape to bear against an opposite side, said sling exerting a force against said opposite side tending to open said rectangular shape when a load is carried by said sling, another side of said rectangular shape being defined by a latch mechanism; and a control line connected to said latch mechanism, said latch mechanism operating in response to a relieving of said force on said opposite side and to a pulling force on said control line to open said rectangular shape and enable removal of said sling from said load from a remote distance after said load has been set in a given position.
2. A device according to claim 1, in which said one side of said frame means is integrally formed with still another side of said frame means opposite said latch mechanism to define an L-shaped portion, said opposite side being pivoted at one end to the free end of said still another side and having its other end coupled to said latch mechanism whereby said opposite side can pivot away from said one side to open said rectangular shape upon operation of said latch mechanism.
3. A device according to claim 2, in which said latch mechanism includes a latch plate coupled to the free end of said one side and overlying the free end of said opposite side, said free end of said opposite side including an extended portion passing beyond said latch plate; and a latch lever pivoted to said latch plate and extending generally parallel to said latch plate to overlie said extended portion, said control line being connected to said latch lever whereby said latch lever must first be pulled free of said extended portion, said latch plate including stop means engaged by said latch lever after said latch lever has been pulled free of said extended portion such that further pulling on said control line then pulls said latch plate free of said opposite ide to free said opposite side whereby a double latching of said opposite side is provided.
4. A device for releasing a sling from lumber, comprising, in combination: a frame member having a leg and arm portion defining a general L-shape, said leg being adapted to be secured to the end of a lumber sling; a holding member pivoted at one end to the free end of said arm and extending generally parallel to said leg such that said frame and holding member defines generally a rectangular shape with one open side, a portion of said sling, after wrapping about lumber, being receivable in said open side to extend upwardly to suitable hoisting apparatus; a latch mechanism coupled at one portion to the free end of said leg and extending across said open side to engage the free end of said holding member; and a control line coupled to said latch mechanism and dangling downwardly therefrom, said latch mechanism releasing said holding member upon applying a pulling force to said control line only when there is no load being carried by said sling, whereby said sling can be released from said lumber after said lumber has been transported to a given position and set in place to relieve the load on said sling, by an operator at a remote point by pulling on said control line.
5. A device according to claim 4, in which said latch mechanism includes a latch plate coupled to the free end of said leg and extending upwardly to overlie the free end of said holding member, said holding member including a notch receiving the overlying portion of said plate and said holding member including an extended portion passing beyond the overlying portion of said plate and having an upwardly sloping surface; a latch lever pivoted to a lower portion of said plate and extending upwardly generally parallel to said plate to overlie said extended portion of said holding member, said control line being connected to said lever at a point spaced from the pivot connection of said lever such that said lever may be pivoted by said control line to cause its overlying portion to ride along said extended portion of said holding member and cam against said sloping surface thereby pivoting said holding member downwardly and remove said notch from the overlying portion of said plate when no load is pressing against said holding member by said sling, said plate including a laterally extending stop means adapted to be engaged by said latch lever after pivoting movement through a given are beyond the extended portion of said holding member such that further pulling on said control line pulls the overlying portion of said latch plate free of said holding member to thereby release said sling.
6. A device according to claim 5, in which said extended portion of said holding member includes a cradling area receiving the overlying portion of said latch lever; and biasing means holding said latch lever in its overlying position of general parallelism to said latch plate such that the pulling force on said control line must overcome said biasing force to move said latch lever after the load on said sling is relieved.
References Cited UNITED STATES PATENTS 1,621,604 3/1927 Ruggles 294-X 2,604,678 7/1952 Mayes 29475X ANDRES H. NIELSEN, Primary Examiner.