US3477596A

US3477596A - Log skidder with cab-controlled cable binder

Info

Publication number: US3477596A
Application number: US596526A
Authority: US
Inventors: Reynold R Michaelson; Philip E Latendresse
Original assignee: Pettibone Mulliken Corp
Current assignee: Pettibone Traverse Lift LLC
Priority date: 1966-11-23
Filing date: 1966-11-23
Publication date: 1969-11-11
Anticipated expiration: 1986-11-11

Description

Nov. 11, 1969 R. R. MICHAELSON ET AL 3,477,596

LOG SKIDDER WITH CAB-CONTROLLED CABLE BINDER Filed Nov. 23, 1966 2 Sheets-Sheet l INVENTORS REYNQLD R. MiCHAELSON BYPHIUP E. LGTENDRIESSE ATTORNEYS Nov. 11, 1969 R. R. MICHAELSON ET AL 3,477,596

LOG SKIDDER WITH CAB-CONTROLLED CABLE BINDER Filed Nov. 23, 1966 2 Sheets-Sheet 2 INVENTORS R-EYNOLD R. MICHAELSON I PHILIP E. LGTENDRESSE I W I,

ATT'ORNEYS United States Patent US. Cl. 214-92 14 Claims ABSTRACT OF THE DISCLOSURE A log skidder is disclosed in which the seizing and release of loads is controlled from the cab. A cable from a hydraulic winch has a large loop at the end thereof threaded through the tips of hydraulically actuated tongs, hung from a boom which can swing downwardly to lower the tongs over a log or group of logs. This movement drapes around the intended load the length of cable spanning between the tips of the tongs. The tongs are then closed sufiiciently to engage lower surfaces of the load. The winch draws the cable in to draw the spanning length thereof taut around the load; the boom swings up to raise the engaged end of the load, and the vehicle moves to drag the load to the desired location, whereupon the load is dropped and the entire vehicle and gear freed therefrom simply by opening the tongs. The tongs may be hydraulically swiveled to lie transversely of an intended load, so that the vehicle need not approach it from a particular angle. For use as a conventional skidder, the tongs may be locked up in the boom, and the cable threaded through pulleys located high enough to lift the log ends by cable pull. Contributing details are disclosed.

The invention of which this disclosure is offered for public dissemination if adequate patent protection is available relates to log skidders. Vehicles called log skidders have long been used in the woods in connection with lumbering operations for dragging logs or tree trunks from a point of felling to a point of further handling such as loading on trucks.

In the past, most log skidders have dragged logs by a cable which required considerable manual labor in applying the cable to the load and eventually in releasing the cable from the load. Various forms of tongs or grapples have been proposed, and some have been used, but difficulties of application, and the possibility of slippage (or the probability of slippage, if more than one log were to be towed) has kept such devices from being sufiiciently satisfactory to widely replace the more conventional manually applied type.

According to the present invention, a cable and tong grapple is provided which may be quickly applied by cab control and which is thoroughly dependable in its grip on the load, whether one log or several. At the same time, for rare problems such as the inability of the vehicle to reach the load, the cable can be payed out over an elevated pulley in the usual manner of conventional log skidders.

Additional objects and advantages of the invention will be apparent from the description and the drawings.

DESIGNATION OF FIGURES FIGURE 1 is a side elevation of the skidder of the present invention, showing in broken lines, the grapple lice being applied to a log, and in full lines, the log being drag ed. FIgICiURE 2 is a plan view of the apparatus shown in FIGURE 3 is a fragmentary view similar to that of FIG. 2 but showing the tongs swiveled to lie transversely of a log which has been approached from the side thereof;

FIGURE 4 is an end view of a log showing the grapple being applied to it;

FIGURE 5 is a view showing the tongs locked to the yoke to hold steady an elevated pulley over which the cable has been drawn;

FIGURE 6 is a detailed sectional view along the line 6-6 of FIG. 5, showing the interlocking of the tongs to the yoke;

FIGURE 7 is a fragmentary view showing the use of the cable for firmly binding a plurality of logs to be dragged; and

FIGURE 8 is a fragmentary sectional view taken approximately on the line 88 of FIG. 5 through the swivel spindle, showing the normal or transverse disposition of the tongs and stop lugs in full lines and in dotted lines showing these parts swung ninety degrees to the limit of movement.

INTENT CLAUSE Although the following disclosure offered for public dissemination is detailed to ensure adequacy and aid understanding, this is not intended to prejudice that purpose of a patent which is to cover each new inventive concept therein no matter how others may later disguise it by variations in form or additions or further improvements. The claims at the end hereof are intended as the chief aid toward this purpose, as it is these that meet the requirement of pointing out the parts, improvements, or combinations in which the inventive concepts are found.

GENERAL DESCRIPTION Except for the features to be described in detail, this skidder may be of various forms and has been illustrated as including front-driven wheels 11, rear-driven wheels 12, a jack-knifing pivot 13*, steering cylinders 14 of which only one is shown, and a cab 16.

According to the present invention, a yoke or boom 18 is pivoted at a low point 19 to chassis 21, and is actuated by a pair of hydraulic cylinders 22.

A grapple assembly 23 hangs by a universal joint 24, seen best in FIG. 5. The universal joint 24 is suspended from the top of the yoke 18 by a stub shaft 26, extending downwardly from a swiveling unit 27.

The grapple assembly 23 includes a rectangular frame 28 (FIGS. 1 and 4) to the lower portion of which a pair of tongs 29 are pivoted. These tongs are actuated in unison by hydraulic cylinders 31. A cable loop 32 is usually secured by release coupling 17 to a main cable 33 wound on hydraulic winch 34.

The tong assembly 23 may be swung to position its tongs transversely of a log by operation of a hydraulic motor 36 forming part of swivel unit 27. The hydraulic motor is located in a protected position largely behind and extending downwardly from the top of yoke 18, and is connected by an enclosed chain drive, represented by 7 chain 35 in FIG. 2, to swivel shaft 26..

3 GENERAL DESCRIPTION OF NORMAL OPERATION In operation, the skidder vehicle is backed up to be adjacent to one end of the log or logs comprising the intended load. Depending on the convenience and the location of a clear path, it may be backed up in the direction toward the end of the log, as seen in FIGS. 1 and 2, or toward the side of the log as seen in FIG. 3, or in any intermediate direction. The driver of the vehicle first operates the correct one of a bank of easily accessible control levers 38 to operate hydraulic motor 36 to turn the grapple assembly 23 to position the tongs 29 transversely of the log, with the rear face of the tongs facing toward the far end of the log. At the same or substantially the same time, he may operate another of the control levers 38 in the direction for operating hydraulic cylinders 31 for opening tongs 29, to the position seen in FIG. 4. Then the driver will operate a third of the levers 38 in the direction for actuating hydraulic cylinders 22 to swing the yoke 18 (and grapple assembly) rearwardly and downwardly to the position shown in broken lines in FIG. 1, with the intervening cable portion 39 draped over the load.

Next, the operator will operate the tong control lever in the opposite direction to close the tongs 29 so that they grip the lower surfaces of the load, somewhat as seen in FIG. 7. They may either wedge themselves under the load as seen in FIG. 7, or merely engage the downwardly facing side portion of the load as seen in full lines in FIG. 1. Unless the load looks precarious, the driver will raise the boom at this time. Before or after raising the boom, the driver will operate still another of the levers 38 to actuate hydraulic winch 34 in the winding direction, pulling in cable 33. This causes cable loop 32 to slip through the tips of tongs 29 and tighten the intervening cable portion 39 about the load. This combined action of the tongs and cable has been found to be extremely reliable, even with the difficult load of a multiple of logs as seen in FIG. 7.

Unless he did so previously, the driver now operates the boom control lever 38 in the opposite direction to raise the boom 18 and with it raise the firmly gripped end of the load. The grapple unit 23 may assume a sloping position in this operation, since friction of the logs on the ground will resist the tendency of the grapple unit 23 to hang down to a vertical position. However, the driver will preferably operate hydraulic winch 34 again to pull in more cable 33 until grapple unit 23 is approximately vertical, so that the entire pulling force exerted on the log will be derived through cable 33. This pulling force incidentally maintains adequate binding tension on intervening cable portion 39. The driver now drives the vehicle, with all the hydraulic control levers 38 in the neutral or hydraulic lock position so that the load is held in the relative position shown in FIG. 1 and dragged or skidded by movement of the vehicle.

When the driver has skidded the log to the desired location, he can merely operate the lever in bank 38 which controls tongs 29 to open the tongs 29, whereupon the log will drop free, and all of the parts will be conditioned for the skidder vehicle to move away. If the movement to the next load to be skidded requires substantial travel, especially over rough terrain it is preferred the tongs 29 be locked in yoke 18, as described below, so that they will not swing and cause damage.

When pulling the log on a sharp turn or the like, the drag of the log tends to swing the grapple assembly 23 toward one side. To guard against excessive movement of this type, and to keep the cable extending rearwardly from the winch, guide rollers 41 are provided at the rear of chassis 21. Preferably, they are sloped with their upper ends rearwardly with respect to their lower ends, so that the cable will tend to pass through them in a direction perpendicular to their common axial plane. There may also be upper and

lower pulleys

42 and 43,

4 USE AS CONVENTIONAL SKIDDER When the skidder vehicle cannot approach a load closely enough for engaging it with the grapple assembly 23, the skidder of this invention can quickly be converted to a conventional type of skidder. This is accomplished by spreading apart the tongs 29 to interlock in yoke 18 as seen in FIGS. 5 and 6, and threading the cable 33 over upper pulley 44 and between guide rollers 46. Usually in this case the cable loop 32 will be released from main cable 33 by operation of a quick release coupling 47. The main cable 33 can then be pulled out (driving hydraulic winch 34 in a paying-out direction) to the inaccessible load, where it is attached to the load in the conventional manner. Then the winch 34 can be operated in the drawing-in direction, drawing the load into adjacency to the vehicle, whereupon the vehicle can be driven to skid the log to its desired destination, and the cable manually released from it.

The interlocking of tongs 29with yoke 18 is easily accomplished. It is merely necessary to spread apart the tongs 29 after aligning them with yoke 18 either by drawing cable 33 or by swinging yoke 18 to the vertical position, which may be at the limit of its movement in the forward direction. The transversely disposed tongs will then be aligned with a recess for their reception formed between rear plate 51 and front plate 52, both welded to yoke 18. Rear plate 51 has been illustrated as extending beyond front plate 52 so that if desired, the tongs can be positioned to swing rearwardly between the two plates 52 and still strike the plates 51.

FURTHER DISCLOSURE The upper section of universal joint 24 carries stop lugs 56 and 57 which strike fixed stop 58 carried by housing 59 of swivel shaft 26 to limit the swivel action. At present the limit is at the ninety degree position in each direction from normal. FIG. 8 shows in dotted lines stop lug 56 engaging stop 58. Others may prefer a little more than ninety degrees. The only need is to avoid interference of the tongs 29 with the cable (especially as it is drawn in) and to avoid excessive twisting of hoses, not shown, running to cylinders 31.

The universal joint 24 need not be of the sophisticated type shown. Two links of chain or linked eyes can serve reasonably well. If less perfect use of the invention is desired for economy, and the hydraulic swiveling is omitted, a simple, swivel, or a spring-centered swivel may be used.

The loop 32 should be very flexible cable, wire rope or the like. Although it suffers considerable wear, it is a short enough piece to be replaced at low cost. It should be long enough, however, to receive any load tongs 29 can receive. The apertures for it through the tongs should be rounded for easy sliding, and may comprise frictionreducing replaceable inserts.

The grapple 23 is preferably painted differently on different sides so that when longitudinally aligned, the operator will know, without remembering, the direction of lever movement which will restore it to normal.

ACHIEVEMENT It is readily apparent from the foregoing description that a skidder of exceptional convenience, dependability and efficiency has been provided. When the skidder can reach the load, all of the fatiguing, costly, and time consuming hand labor for securing the drag cable to the load can be avoided. Very quickly, the operator, 'by hydraulic controls operated from the drivers seat, can apply the grapple unit to the load, securing the load with extreme dependability, and raise the secured end of the load to a position for optimum ease of skidding. Upon reaching the destination, a single hydraulic control at the drivers seat releases the load so that the vehicle is free to move away for the next load. If preferred, the t ngs 29 may be lock d in yoke 18 so that th y ill n t.

swing and cause damage. With such locking, the vehicle can also quickly and easily be converted to a conventional skidder when conventional operation is necessary as when the vehicle cannot get to the load but must winch it out of an inaccessible place. r

. With the preferred (grapple) operation, the more the load resists movement, the tighter it is bound. The greater pull on cable 34 produces greater binding force on intervening portion 39 and tighter gripping by tongs 29, which are preferably providedwith sharp edges 66 (FIG. 5). Tips 67 are also moderately sharp, but having the tongs reach under the load is preferred. It is never necessary, however, to dig manually under a log, sometimes through snow or soil in which it is embedded, as in conventional skidder operation (where a cable must .be passed under a log). A non-wobbling grip is in any event ensured by phasing gear segments 69 (FIG. 7).

No longer need an operator or other worker be exposed to such hazards as broken limbs, due to falling logs or snapping cables, nor to poisonous plants or animalswhere they exist.

A further advantage is that the pull of the cable is at a much lower point on thevehicle than on conventional skidders, contributing to greater stability and much improved safety.

Hydraulic motor 36 can be turned by chain 35, when a dragged log swings in turning. This is permitted by cross-relief valve 71 (shown schematically in FIG. 2) there being no irreversible gearing. Also, because such forces are too great to restrain, stop 58 is a shear pin readily replaced. It may be a bolt with a pair of lock nuts. It will shear ofi harmlessly (except for its own replacement in the field) if tongs 29 are applied wrong way about, in the FIG. 3 situation.

We claim:

1. A skidder for elongate loads including a vehicle having a drivers position, and load handling and skidding means carried by the vehicle and includingelevating means and a grapple hung from the elevating means, said elevating means and grapple being capable of elevating the leading end of an elongate load, characterized by:

power winchmeans on the vehicle, a cable leading therefrom to the lower part of the grapple to drag the load asthe vehicle moves and to adjust the I I hanging angle of the grapple;

said grapple including tongs and a flexible binder intervening between the lower portions of the tongs and drawn by the cable for tightening about the load in the tongs for skidding the load; and

control means accessible at the drivers position for controlling the elevating means and tongs and the Winch means; said elevating means being operable independently of thewinch, cable and binder.

2. A skidder according to claim 1 including guide means for a cable substantially above the tongs, through which a cable can be payed out to be manually engaged to a load spaced from the vehicle too far for engagement by the tongs and from which a lifting'component will be derived.

'3. A log skidder according to claim 1 including guide means for the cablenear the level of a raised load and additional guide means for the cable substantially higher, through which a cable can be payed out to bemanually engaged to a'load spaced from the vehicle 'too far for engagement by the tongs and from which a lifting component will be derived.

4. A skidder according to claim 1 in which the elevating means is a boom in the form of an inverted U with the tongs hingedly hanging from the top of the boom, and means for locking the tongs with respect to the legs of the U to prevent swinging of the tongs when no load is being carried by them.

5. A skidder for elongate loads including a vehicle having a drivers position, and load handling and skidding means carried by the vehicle and. including elevating means and a grapple hung from the elevating means, said elevating means and gapple being capable of elevating the leading end of an elongate load, characterized by:

power winch means on the vehicle, a cable leading therefrom to the lower part of the gapp'le to drag the load as the vehicle moves and to adjust the hanging angle of the grapple;

said grapple including tongs and a flexible binder intervening the lower portions of the tongs for tightening about the load in the tongs for skidding the load; and

control means accessible at the drivers position for controlling the elevating means and tongs and the winch means; in which the elevating means is a boom in the form of an inverted U with the tongs hingedly hanging from the top of the boom, and means for locking the tongs with respect to the legs of the U to prevent swinging of the tongs when no load is being carried by them, said locking means comprising interlocking means for providing interlocking engagement between the tongs and the legs of the U when the tongs are spread apart while said interlocking means are in alignment.

6. A skidder for elongate loads including a vehicle having a drivers position, and load handling and skidding means carried by the vehicle and including elevating means and tongs hung from the elevating means, said elevating means and tongs being capable of elevating the leading end of an elongate load, characterized by:

self elevating means being'a boom in the form of an inverted U with the tongs hingedly hanging from the top of the boom, and means for locking the tongs with respect to the legs of the U to prevent swinging of the tongs when no load is being carried by them, said locking means comprising interlocking means for providing interlocking engagement between the tongs and the legs of the U when the tongs are spread apart while said interlocking means are in alignment.

7. A skidder for elongate loads including a vehicle having a drivers position, and load handling and skidding means carried by the vehicle and including a grapple, elevating means hanging the grapple therefrom, said elevating means and the grapple being capable of elevating the leading end of an elongate load, characterized by:

power winch means on the vehicle, a cable leading therefrom to the lower part of the grapple independently of the means hanging the grapple to drag the load as the vehicle moves and to adjust the hanging angle of the grapple;

said grapple including tongs and a flexible binder freely passing through the tongs and intervening between the lower portions of the tongs and drawn by the cable for tightening about the load in the tongs in response to tension on the cable for skidding the load; and

control means accessible at the drivers position for controlling the elevating means and tongs and the winch means.

8. A skidder for elongate loads including a vehicle having a drivers position, and load handling and skidding means carried by the vehicle and including a grapple, elevating means having means hanging the grapple therefrom, said elevating means and grapple being capable of elevating the leading end of an elongate load, characterized by:

said grapple including tongs and a flexible binder intervening between the lower portions of the tongs and drawn by the cable for tightening about the load in the tongs for skidding the load;

p'owered swiveling means forming part of the elevating and hanging means for swinging the tongs angularly about a generally vertical axis to lie crosswise of the elongate load when the vehicle is not aligned with the load length; and

9. A skidder for elongate loads including a vehicle having a drivers position, and load handling and skidding means carried by the vehicle and including a grapple, elevating means having swivel means hanging the grapple therefrom, said elevating means and grapple being capable of elevating the leading end of an elongate load, characterized by:

power winch means on the vehicle, a cable leading therefrom to the lower part of the grapple independently of hanging the grapple to drag the load as the vehicle moves and to adjust the hanging angle of the grapple;

said grapple including tongs and a flexible binder freely passing through the tongs and intervening between the lower portions of the tongs and drawn by the cable for tightening about the load in the tongs in response to tension on the cable for skidding the load;

powered swiveling means forming part of the elevating means for swinging the tongs angularly about a generally vertical axis to lie crosswise of the elon gate load when the vehicle is not aligned with the load length; and

means limiting the swivel movement of the swivel means to prevent entanglement of the tongs and cable.

10. A skidder for elongate loads including a vehicle having a drivers position, and load handling and skidding means carried by the vehicle and including a grapple, elevating means including a boom pivoted at its lower forward end, means hanging the grapple from the upper rearward portion of the boom, said elevating means and grapple being capable of elevating the leading end of an elongate load, characterized by:

said grapple including tongs and a cable tensioned flexible binder intervening between the lower portions of the tongs for tightening about the load in the tongs for skidding the load; and

11. A skidder for elongate loads including a vehicle having a drivers position, and load handling and skidding means carried by the vehicle and including a grapple, elevating means including a boom pivoted at its lower forward end for pivoting about a horizontal axis fixed as to the vehicle, means hanging the grapple from the upper rearward portion of the boom, said elevating means and grapple being capable of elevating the leading end of an elongate load, characterized by:

power winch on the vehicle, a cable leading therefrom to the lower part of the grapple independently of the means hanging the grapple to drag the load as the vehicle moves and to adjust the hanging angle of the pp said grapple including tongs and a cable tensioned flexible binder intervening between the lower portions of the tongs for tightening about the load in the tongs for skidding the load;

said skidder including powered swiveling means carried by the boom near its top for swinging the tongs angularly about a generally vertical axis to lie crosswise of the elongate load when the vehicle is not aligned with the load length; and

control means accessible at the drivers position for controlling the elevating means and tongs and the swiveling means and the winch means.

12. A skidder for elongate loads including a vehicle having a drivers position, and load handling and skidding means carried by the vehicle and including elevating means and a grapple hung from the elevating means and which can be lowered by the elevating means for gripping the leading end portion of an elongate load, said elevating means and the grapple being capable of elevating said leading end, characterized by:

power winch means on the vehicle, a cable leading therefrom to the lower part of the grapple independently of elevating means to drag the load as the vehicle moves, said winch being operable to take slack out of the cable to prevent a swinging back of the hung grapple as the vehicle starts, and to adjust the hanging angle of the grapple;

said grapple being power actuated for gripping the load and designed to drop the load upon release of the gripping action; and

control means accessible at the drivers position for controlling the elevating means and grapple and the winch means.

13. A skidder for elongate loads including a vehicle having a drivers position, and load handling and skidding means carried by the vehicle and including elevating means and a grapple hung from the elevating means and which can be lowered by the elevating means for grip ping the leading end portion of an elongate load, said elevating means and the grapple being capable of elevating said leading end and said elevating means being a boom pivotable through an angularity substantially changing the proximity of the load to the winch, characterized by:'

power winch means on the vehicle, a cable leading therefrom to the lower part of the grapple independently of elevating means to drag the load as the vehicle moves, said winch being operable to take slack out of the cable to prevent a swinging back of the hung grapple as the vehicle starts, and to adjust the handling angle of the grapple; and

14. A skidder for elongate loads including a vehicle having a drivers position, and load handling and skidding means carried by the vehicle and including elevating means and a grapple hung from the elevating means and which can be lowered by the elevating means for gripping the leading end portion of an elongate load, said elevating means and the grapple being capable of elevating said leading end and said elevating means being a boom pivotable through an angularity substantially changing the proximity of the load to the winch, characterized by:

power winch means on the vehicle, a cable leading therefrom to the lower part of the grapple independently of elevating means to drag the load as the vehicle moves, said winch being operable to take slack out of the cable to prevent a swinging back of the hung grapple as the vehicle starts, and to adjust the hanging angle of the grapple; and

control means accessible at the drivers position for controlling the elevating means and grapple and the winch means; said cable being readily separable from the hanging grapple for use independently of it in winching a load from an inaccessible point.

(References on following page) References Cited UNITED STATES PATENTS Larson 214653 Westfal1 214523 XR Sandland.

Hollis et a1 294-111 XR Larson.

Woodside et a1.

10 FOREIGN PATENTS 3/1932 France. 2/1966 Germany.

5 ALBERT J. MACKAY, Primary Examiner