US 3003653 A
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Oct. 10, 1961 A. R. WIRKKALA LOG LOADER Filed March 3, 1958 United States Patent 3,003,653 LOG LOADER Albert R. Wirkkala, Naselle, Wash. Filed Mar. 3, 1958, Ser. No. 718,816 1 Claim. (Cl. 214-147) This invention relates to improvements in machines of those types generally referred to as log loaders, and it has reference more particularly to improvements in those log loaders which are of the conventional power shovel type employing a boom that carries an extendable and retractable dipper stick equipped at its outer end with a pair of tongs whereby the logs, beams, or whatever maybe the articles being handled, are gripped and held when being picked up and moved for loading, piling or for otherwise handling them.
It is the principal object of this invention to provide a log loader of the above stated character wherein the tongs are directly connected to the end of the dipper stick by a swivel that maintains them under direct control of the dipper stick for positive placement as distinguished from the relatively uncontrolled placement of tongs that are suspended from the dipper stick or from a boom by a cable.
It is also an object of the present invention to provide tongs that, by reason of the present swivel connection with the dipper stick, will automatically adjust themselves to the position of the log to be picked up when brought into contact therewith by movement of the stick, thus eliminating the need for manual setting of the tongs on the log.
More specifically stated, the objects of the present invention reside in the attachment of a pair of log gripping tongs preferably those of my US. Patent No. 2,786,709, to the end of the dipper stick of the conventional form used with a power shovel type of log loader, by means of a swivel connection which permits the opened tongs to automatically adjust themselves upon proper contact with the log to be lifted, to a position for gripping it.
It is a further object of the invention to provide, in a loading machine of this kind, a form of swivel connection that permits the functional application of the tongs under full control of and by the machine operator through his manipulations of the boom and dipper stick.
Still further objects and advantages of the invention reside in the provision of a tong attaching swivel through which the positioning of the tongs may be positively controlled.
ln accomplishing the above mentioned and other objects of the invention, 1 have provided the improved details of construction, the preferred forms of which are illustrated in the accompanying drawings, wherein:
FIG. 1 is a side view of a log loader having a pair of tongs close coupled to the end of the dipper stick by a swivel in accordance with the teaching of the present invention.
FIG. 2 is an enlarged perspective view of the tongs and their mounting swivel as applied to the end casting of the dipper stick.
FIG. 3 is a view illustrating the open tongs with a log.
FIG. 4 is a sectional detail illustrating an alternative form of swivel for use attaching the tongs to the dipper stick.
FIG. 5 is a sectional detail illustrating yet another form of swivel for use in the present combination of parts.
Before proceeding with the description of parts and their mode of operation, it will be stated that loaders of the shovel type have previously been employed for log loading, but to my knowledge the dipper stick of such a machine has been equipped at its outer end, either with mode of engaging the 3,003,653 Patented Oct. 10, 1961 "ice 1" 4 mechanically powered log gripping tongs that are set in a plane transversely of the boom, for example, in US. Patent No. 2,757,037, or when a boom only is used, paired tongs have been suspended by a cable that extended along the boom and over a fairleader at its outer end, as for example, in US. Patent No. 2,327,015.
In the use of those loaders equipped with mechanically or power operated tongs, it is required that the dipper stick and the log that is to be picked up be brought substantially into alignment before the tongs can be properly engaged therewith. In those loaders using tongs suspended by a cable, it is impossible to adequately control the position of the tongs and they must be set on the log by hand.
The present invention employing the short coupled swivel connection permits the tongs to be applied under control of the loader operator through his deft movement of the boom and the endwise adjustment of the stick; this being facilitated also by reason of the particular tongs being used.
Referring more in detail to the drawings:
In FIG. 1, I have illustrated one of the present day types of log loaders; this being referred to as of shovel type. It comprises a turntable form of base structure 10, supported for travel on crawler tracks 11. Mounted on the turntable is a cab 12 enclosing therein the usual engine and controls for driving of drums on which cables for effecting movements of the boom 13 and its dipper stick 14 are wound.
The boom 13 is here shown as being pivoted on the turntable, as at 15, for up and down movement, at its outer end, in a vertical plane; this movement being controlled through a cable connection designated at 16. The dipper stick 14 is mounted on the boom in the usual guide 17, for extension and retraction; these adjustments of the stick being effected by the usual mechanisms not herein shown and to which no claim is made.
The dipper stick 14 is equipped near its outer end and at its underside, with a transversely directed log heeling plate 18 which, preferably, is toothed along its edge as shown at 19 in FIG. 2. The up and down movements of the outer end of the dipper stick, relative to the boom, are controlled by a cable connection designated at 20.
Fixed to the outer end of the dipper stick 14 is a metal head or casting 24 equipped at its end with a bearing 25. This bearing is formed with a vertically directed bore in which a swivel bolt 27 is mounted. At its lower end the bolt has a yoke 28 attached thereto by a horizontal pivot pin 29.
The log handling tongs as here shown comprises crossed tongs 30-30', pivotally joined at their crossing point near their upper ends, by a bolt 31. At their upper ends the tongs are equipped, respectively, with the usual clevises, 3232', and these are looped through the yoke 28. The tong 30 has an extension 33 beyond the clevis 32, to which a cable 34, for opening the tongs, is attached. This cable extends from its point of connection with tong 3-0 about a small sheave wheel 35 mounted on tong 30 below the pivot bolt 31, thence upwardly and through a guide loop 36 that is fixed to bearing 25, as shown best in FIG. 2, thence along the dipper stick and to the cab 12 for ready access thereto by the operator. The weight of the tongs normally moves them toward closed position. To open the tongs for application, the operator draws inwardly on the cable 34. This swings the tong 30 upwardly, while tong 30 extends substantially directly downward to some distance below the end of tong 30 as for example to the open position of FIG. 3.
The particular advantage of the close coupled mounting of the tongs at the end of the dipper stick by the swivel resides in the fact that the position or location of the tongs can be positively controlled. Then, assuming that the tongs are in the open position, 'as shown in FIG. 3, to apply them to a log, regardless of its direction on the ground, it is only necessary that the operator so manipulate the boom, stick and turntable, that the tongs be swung in a direction across the log at such level as to cause the depending tong to strike against the side thereof. This will cause the tongs, if not already in proper position for closing on the log, to be swung on the swivel, to a position across the log. For example, if the open tongs as carried by the stick were in a vertical plane parallel to the log, when the depending tong 30 struck the log, the continued travel of the stick across the log would cause the paired tongs to swivel to the position of FIG. 2, placing the tong 30 across the top of the log. Then, upon release of cable 34 by the operator,
'the tongs would close on opposite sides of the log and when lifted by the boom or stick, would. grip it. Heeling 'of the log against plate 18 is effected in the usual way by the operator. He, also, by making certain adjustments of turntable, boom and stick, can quickly turn a log end for end without releasing the tongs, and without losing positive control of the log. Other advantages, resulting directly to the close coupled swivel connection, will be apparent to persons familiar with the logging industry and log loading operations.
In FIG. 4, I have shown an alternative form of swivel. In this an eye bolt 50 is rotatably mounted in a bearing 51 set in the outer end of the head 24 and extends horizontally from the end of the stick. A swivel 52 is suspended from the eye of this bolt. This swivel has an eyelet 52' at its lower end to which the clevises 32 and 32' of a pair of tongs may be applied in the same manner 'in which they are shown as being applied to yoke 28 in FIG. 2. 7
Yet another form of swivel mounting is seen in FIG. 5. In this, a swivel '4 like that of FIG. 4 has the eye 54 at its upper end applied to a U-shaped mounting member 55 secured in the end block of the head 24. .The swivel 54 swings freely in the U-bolt member 55, and the lower eye 54x of the swivel can rotate freely about the axis of the swivel.
Loaders employing the close coupled, swivel connection for the tongs, as here shown, or employing tongs of other'forms, can be quite advantageouslyemployed. They facilitate and expedite the work of loading logs, rails, or the like, and also materially reduce loading cost by reason of the elimination of the man usually used for. properly setting the tongs on the log that is to be lifted.
It is to be understood that the present invention is not to be confined to loaders of the shovel type herein illustrated but also is applicable to loaders of various types such as, for example, the type shown in the patent to H. Carlson, No. 2,327,015, previously mentioned. The gist of the invention resides primarily 'in the close coupled swivel connection of tongs to boom or to dipper stick which permits positive control of placement of the tongs on the log, and secondly in the use of tongs of the character disclosed, or of similar tongs that may be controlled by a cable connection leading to the operators position on the machine.
The term log loader is used in the following claim to designate a machine of the kind disclosed which may be used for loading logs, beams or other objects which may be handled in a like or similar manner.
What I claim is:
A log loading device comprising a boom, a swivel support means rigidly attached and immovably fixed to the outer end portion of said boom, a swivel having the upper end thereof connected to said swivel support means, a yoke at the lower endof said swivel, a pair of crossed tongs pivotally connected to one another adjacent the upper ends thereof, 'a clevis connected to the upper end of each of said tongs, each of said clevises being connected to said yoke for supporting the tongs from the swivel, one tong of said pair of tongs having a sheave wheel mounted thereon below the point of pivotal connection of the tongs, a cable guide at the outer end of said boom adjacent said swivel support means, and a tongcontrol cable extending outwardly along the boom through said guide, downwardly and about said sheave wheel and connected to the upper end of the other tong whereby the tongs may be positively maneuvered into operative position relative to a log or the like by moving the boom, and opening and closing of the tongs may be remotely controlled by means of said control cable.
References Cited in the file of this patent UNITED STATES PATENTS 1,429,161 Newlin Sept. 12, 1922 1,525,197 Ranger Feb. 3, 1925 2,375,205 Barras May 8, 1945 2,566,616 Larson Sept. 4, 1951 2,656,059 Troyer Oct. 20, 1953 2,786,709 Wirkkala Mar. 26, 1957 2,893,778 Eckstein July 7, 1959