US2757037A - Log loading tongs - Google Patents

Description

July 31, 1956 M. D. TROYER LOG LOADING TONGS 2 Sheets-Sheet 1 Filed May 8. 1953 pl|||l| llllllll-L IN V EN TOR. M/lec 0. 7/20 YER;

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mmemsvs July 31, 1956 M. D. TROYER LOG LOADING TONGS 2 Sheets-Sheet 2 INVENTOR. M17196 0. 7X 0YB BY f) KITTORNEYJ Filed May 8, 1953 United States Patent LOG LOADING TONGS Application May 8, 1953, Serial N 0. 353,756

1 Claim. (Cl. 294-88) This invention relates to improvements in log handling equipment. More particularly it has reference to apparatus or devices which in present day logging operations are known as Air Tongs; such devices generally being mounted at the end of a shovel boom stick and comprise a pair of tongs operable by an air cylinder, under control of the shovel operator, to pick up and load logs.

More specifically stated, the present invention is an improvement upon the log handling equipment disclosed and described in U. S. Patent No. 2,613,831, issued on October 14, 1952 to L. N. Rees; the improvement residing primarily in the arrangement and functional relationship of the paired tongs and the power cylinders whereby the tongs are opened and closed.

It is the principal object of this invention to provide log handling equipment which is similar in purpose to that of the above mentioned patent to Rees, and also is similar to that of my co-pending application, filed under Serial No. 111,811 on August 23, 1949, now Patent No. 2,656,059, issued Oct. 20, 1953, but which is characterized by various novel structural differences and a new arrangement of parts that result in the attainment of operational as well as manufacturing advantages.

More specifically stated, the objects and advantages of the present invention reside in the provision of a log handling apparatus that is characterized by the use therein of a pair of log handling tongs that are mounted in a supporting frame upon the same pivot pin, and are actuated between open and closed positions by individual power cylinders, thus to gain various advantages in operation not afforded when the tongs are mounted on laterally spaced mountings, and operated by a single power cylinder as in the case of the Rees patent and in the device of my copending application.

Further objects and advantages of the present invention reside in the details of construction and combination of parts of the present apparatus and in their mode of operation as will hereinafter be fully described.

In accomplishing these and other objects of the invention, I 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 shovel having a boom stick equipped with an air tong apparatus embodying the improvements of the present invention therein.

Fig. 2 is a plan view of the frame structure of the present apparatus wherein a pair of tongs and their operating cylinders are to be mounted.

Fig. 3 is a perspective view of the present air tong mechanism, as seen from the under side.

Fig. 4 is a front elevation of the present air tong mechanism, with a part of its supporting frame structure broken away to better show the air cylinder arrangement.

Fig. 5 is a side view of the present mechanism, with the tongs applied to a log and the log engaged with the heeling plate.

2,757,037 Patented July 31, 1956 Fig. 6 is a diagrammatic view showing the two power cylinders and their air line connections and control valve.

Referring more in detail to the drawings:

The present improvement, like the device of my 00- pending application previously mentioned, is applicable to those various types and makes of machines, or cranes of the power shovel category, employing a boom that extends upwardly and outwardly from a turntable form of support, and which boom is adapted to be raised and lowered to various positions and is equipped with an extendable and retractable boom stick.

In showing the present log handling equipment, it has been disclosed in Fig. 1 as functionally appliedto the outer end of a shovel boom stick. In this view, a portion of a power shovel mechanism has been designated in a general way by reference numeral 10. It comprises a crawler track base structure 11 that supports a platform 12 on which a turntable 13 is mounted. Mounted on the turntable is a cab 14 in which the various controls and operating mechanism for the present device, not herein shown, are located. Hinged to the turntable as at 15, is a boom 16, equipped at its outer end with sheave Wheels, as at 18, over which a cable 19 is extended in the usual manner for supporting and for making the necessary operational adjustments in elevation of the boom.

Supported by and extending forwardly from the boom 16, is a boom stick 20; this having its inner end portion slidably contained in a guide bearing or housing 25 that is pivoted on the boom by a transverse pivot shaft 26. The stick 20 is shown to be equipped with a longitudinally extending rack bar 27, through which, by means not herein shown, the stick can be extended, retracted and held at a set position. To angularly adjust the boom stick in a vertical direction, and also to support it, a cable 32 is extended from a suitable cable winding drum mounted on the patform 13 but not herein shown; this cable passing over sheaves 33 at the outer end of the boom and then forwardly and about a sheave 34 contained in a block 35 that is pivotally attached, as presently explained, to the frame structure that is mounted on the outer end of the boom stick, as shown in Fig. 1.

It is to be understood that adjustments and the control of the boom and boom stick may be accomplished by the usual or by any other suitable means. This, however, forms no part of the present invention.

Attached rigidly to the outer end of the boom stick 20 is the present air tong mechanism. This mechanism comprises a substantial and rigid frame structure shown in Fig. 2, to include a rather narrow and elongated,

forward box-like portion, disposed transversely of theline of the boom stick and having front and back walls 40-40', and opposite end walls 4141. Fixed to the back wall 40', substantially perpendicularly thereto is a second box-like structure comprising laterally spaced, opposite side plates 4242', that are adapted for fixed securement at their rearward ends to the outer end of the boom stick 20, as has been shown in Figs. 1 and 5. Web plates 45 are applied to the back wall of the forward frame and extend along the side plates 4242' integral therewith, to give added rigidity to the frame structure. Also, top and bottom plates 46 and 46' extend between and join the side plates 42-42, and a pair of spaced flanges 48--48 extend upwardly from the top plate 46 and it is between these that the sheave block 35 is pivotally attached by a pivot bolt 49.

Fixed transversely to the underside of the rearwardly extending portion of the tong mounting frame structure is a heeling plate 50 with a serrated lower edge, as has been shown in Fig. 3.

Mounted centrally in the transversely directed or forward box-like portion of the frame structure, is a pair of 3 log handling tongs, 60 and 60'. These tongs are pivotally supported on a pivot bolt 61 that extends between and through the front and back walls 40--40', medially of the end walls 41-41. Each tong is of bell-crank lever form and comprises a lower end portion that as seen in Fig. 4, curves outwardly and downwardly from the pivot pin 61, and an operating lever portion 62 that extends upwardly from the pivot point. The lower portions of the tongs are so shaped as to adapt them to receive a log between them. As here shown, the tongs are equipped at their lower ends with teeth 63 to hcldingly engage with the log.

For controlling the opening and closing action of the paired tongs, I provide a pair of double acting air cylinders, 64-64 located within opposite end portions of the transversely directed frame, each of which cylinders is pivotally fixed at its outer end between paired ears 65 that extend inwardly from the adjacent end wall, by a pivot pin 66. Each cylinder contains a piston 68 with a rod 69 extending therefrom and from the inner end of the cylinder, and pivotally connected at its outer end, as at 70, to the outer end of the lever arm 62 of the corresponding tong.

Air under pressure is adapted to be admitted selectively to outer or inner ends of the air cylinders for the opening and closing of the tongs, and for holding them engaged with a log. In Fig. 6 I have diagrammatically shown air supply lines 71 and 72 extended to lines 73 and 74 that, respectively, connect the inner ends and the outer ends of the two cylinders. The lines 71 and 72 lead from opposite sides of a four way valve 75 through which air may be admitted from a source of supply, designated at 76 either to the line 71 or 72.

It is advisable that the tongs be limited in their closing and opening movements and for this purpose cross bars 78 are extended between the side walls 40-40 to be engaged'by the lever arms 62 when swinging outwardly, and lower cross members 79 are extended between the side plates to be engaged by the tongs to limit their opening action.

For attachment of sling lines, should such be desired, the tong mounting frame structure is equipped centrally of its forward wall 40 with a hook 80, and at its opposite ends with hooks 81-81.

It is to be understood that the details of construction of the frame structure are not critical, and the frame structure might be secured to the boom in various ways other than herein shown. The novelty is believed to reside primarily in the use of tongs mounted in a rigid frame structure on a pivot pin that is common to both,

and having individual actuating cylinders disposed relationship thereto that is herein shown.

Having thus described my invention, what I claim as new therein and desire to secure by Letters-Patent, is:

In a log handling apparatus of the character described including a boom stick or the like, a frame structure secured to the outer end of the boom stick as an extension thereof and in fixed rigid relationship thereto, said frame having a rectangular box like portion at its outer end, said box including parallel front and back walls each positioned in a plane substantially perpendicular to the longitudinal axis of the boom stick and including opposite end walls joining the front and back walls at the outer ends thereof, a tong mounting pin mounted in and extending between the front and back walls medially of their ends, a pair of tongs pivotally mounted on said pin intermediate the ends of the tongs, each of said tongs comprising a log gripping jaw and an integral lever portion extending from the upper end of the jaw, a pair of independently operable power cylinders laterally spaced and each pivotally mounted at one end on a respective one of said end walls between the longitudinal axes of the cylinders substantially parallel to the front and back walls, the longitudinal axes of said cylinders being upwardly inclined, each of said cylinders having a piston therein and a piston rod extending along the longitudinal axis from the free end of each cylinder and each such rod being pivotally connected at its free end to the lever portion of its respective tong, a fluid reservoir having fluid under pressure therein and a pair of fluid conveying means each connected at one end to the reservoir and at the other end to each cylinder, the connection between one fiuid conveying means and the cylinders being adjacent the ends of the cylinders fixed to said end walls and the other fluid conveying means being connected adjacent the free ends of the cylinders, and means for controlling the application of fluid to the pistons of the respective cylinders whereby the respective pistons are actuated in the cylinders to cause the tongs to grip or release a log.

in the References Cited in the file of this patent UNITED STATES PATENTS 1,307,009 Joy June 17, 1919 2,390,293 Colson Dec. 4, 1945 2,488,767 Drott et a1 Nov. 22, 1949 2,613,831 Rees Oct. 14, 1952 2,639,937 Billings May 26, 1953 2,656,059 Troyer Oct. 20, 1953

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