CA1163240A - Transport device mainly intended for pulling tree trunks and similar loads - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A transport device, comprising an elongate element in the form of a flexible band to which is connected a plural-ity of hollow cylindrical holding members each having a hook for attachment of a load. One end of the band is attached to a fixed location and its other end is connected to means for imparting a reciprocating movement to the band.
Each member is freely movable in one direction along the band so that it can be positioned over a load to be picked up, but in the return direction (with the load) is locked to the band by means of a ball which is wedged between one of a number of raised portions of the band and an angled interior wall of the member.

Description

1 163~4~

The present invention relates to a transport device for transporting a load, e.g. tree trunks, along a path by means of an elongated element enabling the load to be released at a desired location. The elongated element i6 given a re-ciprocating movement in its longitudinal direction and at least one holding member is attached to the elongated element.
The holding member is arranged to move the load in one of the directions of motion of the elongated element and in the opposite direction to slide on the elong~ted element without moving the load.

In forestry work the transport of cut tree trunks to a road which is accessible to large transport vehicles is of-ten a problem. This problem is today solved in many different ways. One way is to employ a cross-country forwarder or wheel tractor transporting the tree trunks to the road.

This is however notalways the most convenient solu-tion, e.g., when only certain trees have been cut for thinning purposes and other trees are left standing. These remaining trees reduce the passability considerably for forwarders and similar vehicles.

A winch, e.g. mounted on a timber truck, is another alternative. When the tree trunks, which often are sporadi-cally placed over a large area and in different distances from the road, are dragged to the road and loaded on the transport vehicle, the wire is manually drawn from the winch to the tree trunk to which the wire is connected.
The distance from the winch to the tree turnk is however limited to the length of the wire which often is insuf-ficient. The manual drawing of the wire to a new tree Lrunk-after each trailing of another tree trunk is a time consuming and labour intensive procedure which also increases the costs for loading and transport.
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In the US patent specification 3l566,801 a transport device is described which comprises a wire or a rope extending between two supporting means, means foroscillating the rope in the direction of its length at a very low amplitude (about 6 mm at a frequency of 50 vibrations per second) and a car-riage, which by way of a holding device is connected with and driven by and along said rope.

This transport device cannot be used for the purpose for which the present invention is intended. Firstly, the amplitude of the oscillating movemer.t of the rope i6 too low for trailing tree tr~nks, considering the self-elongation of the rope. Great forces are required for the trailing of tree trunks ana these forces tend to temporarily stretch the rope.
Secondly a holding device comprising shafts, teeth and toothed wheels cooperating with pawls or similar, is not sufficiently reliable and durable for use in forestry where such a device has to withstand rough handling, foreign matter such as soil, stones, springs, twigs and ice, and very low temperatures.
Furthermore, since large tractive forces have to be applied to the rope, it is also very important that the holding de-vice can bring about a complete locking in one of the direc-tions of motion of the rope and at the same time it can be easily freed from the rope in the opposite direction of motion.
This has proved very difficult to achieve.

In the Swedish printed publication 7409119~0 a warping system is described having an endless wire and shifting means in front of the pulley wheels of the wire. The shifting means moves jaw means from the incoming to the outgoing wire.
The jaw means require an exact guiding to the shifting units, which is very difficult to achieve, and since the jaw means have a clamping effect only in loaded condition, a safe re-turn of the jaw means cannot be guaranteed. The system com-prises many units cooperating with each other and each com-prising a number of moveable parts, which in forest areas, ~ 16324(1 where sand, gravel etc. easily can come into the structural members after a short time, are put out of operation.

Also clamping devices of different kinds are pre-viously known, e.g., through the British patent specification 651,556, which lock to the wire in one of the directions of motion of the wire and release in the opposite direction of motion. In order to provide an effective locking, the angle or taper of the clamping wedge has to be small which means that for releasing the wire a large force is re~uired, which can not be achieved by means of aspring, elastic band or the like.

The object of the present invention is to eliminate the above mentioned drawbacks and to provide a simple and re-liable transport device, which facilitates the trailing of tree trunks, reduces the transport costs, has holding members comprising no or only a few moveable parts, which withstands rough handling, coarse lumps of foreign matter a~d low temper-atures, and which fulfills the demand for providing an effec-tive locking of the band and which can take up large loads while at the same time being very easy to loosen.

Since the transport device can be used in very rough country and environment it can also be used for military purposes as transport of ammunition, supplies and/or injured.
The invention has for this purpose been so arranged that it can maintain transport in both directions between two or maybe more points with relatively large distances between them, and even across lakes, watercourses, etc.
Accordingly, the present invention provides a transport device for transporting a load along a path of transport between at least two points comprising, an elongated element extending along the path of transport, an anchoring member attached to one end of said elongated member, a dri-ving means attached to the other end of said elongated element f 1~324() for producing a reciprocating movement of said elongated element in its longitudinal direction, at least one unidirec-tional~load carrying gripping member releasably engaging said elongated element and operable to grip said elongated ele-S mentwhen it is reciprocating in the desired direction of trans-port and release said elongated element when it is reciprocating in the opposite direction, and means for attaching a load to be transported to said gripping element, said gripping ele-ment comprising a hollow casing member having a bore extending therethrough, a longitudinal slot extending through the wall of said casingthroughwhich said elongated element is insertable so that said gripping element may be engaged with and removed from said elongated element, releasable retaining means for retaining said gripping element in engagement with said elongated element, unidirectioned locking members in said casing operatively associated with said elongated element to move said gripping member along the path of transport, and a releasing member attached to said elongated element at a desired unloadingpositionto cooperatively engage said grip-ping member to release said retaining means and remove said gripping member from enyagement with said elongated member.

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings:-Figure 1 is a schematic side view of the transport device according to the invention, Figure 2 is a view from above of the transport de-vice according to Figure 1, Figure 3 is a side view of a holding member, Figure 4 is a cross-section through the holding mem-ber according to Figure 3, 1 16324(~

Figure 5 is a longitudinal section through the holding memher according to Figure 3, Figure 6 is a view from above of a releasing member, .

- 4a -~ 1~324~

Figure 7 is a cross-sect~.on throu~h the releasing mem-ber according to Fi~ure 6, Figure 8 illustrates a workin~ moment when a holdin~
member is released, Figure 9 is a longitudinal section through an alterna-tive embodiment of a holding member, Fiyure 10 is a section according to the line X-X in Figure 9, Figure 11 is an end view of the holaing member accord-ing to Figure 9, Figure 12 is a longitudinal section through a pull band according to the invention, Figure 13 is a cross-section throuyh the band according to Figure 12, Figures 14 and 15 show a further embodiment of a hold-ing member with the pull band in two different positions, Figures 16 and 17 show a longitudinal section and a cross-section through a further embodiment of a holding member~

The transport device 1 comprises mainly a winch 2 driven by a driviny means, a pull band 3, a flexible element 4 and at least one, preferably a plurality, of holding members 5 intended to be attached on the pull band 3.

The driviny means is preferabl~ a hydraulic motor of conventional kind, but can of course as well be an electric motor, a pneumat;`c motoX or an internal combustion motor. The band 3 is given a reciprocat~ng motion by the winch 2, the amplitude of ~ 16324~

which can be ~aried within broad lim~tsr but should at least exceed some dec~mete~s in order to have the transport de~ice working satis~actory. Practical test have shown that a recipro-cating motion with an amplitude between 1-10 and up to 30 ~eters is p~rticularly favourable. The winch 2 is prov;ded with a fix-ing device 7, by means of which it can be connected to a support 8, e.g. a tree, a vehicle or similar.

The band 3 preferably comprises a woven, flat strip with a low self-elongation, e.g., made of a synthetic textile material.
The band 3, which has a substantially square cross-section, has several advantages, which will be mentioned later.

The end of the band 3 facing the winch 2, to so called driving end 3a, is connected to the winch drum and the oppositeend of the band, the coupling end 3b, is connected to a further sup-port 9, e.g. a tree, by way of a flexible element 4. This flex-ible element can e.g. consist of a rubber member, a spring-loaded wire or one or more tension springs, and exerts a substantially uniform tractive force in the coupling end 3b of the band 3 and opposed to the tractive force exerted by the winch. The tractive force of the flexible element 4 is much smaller than the tractive force exerted by the winch 2 and its only purpose is to keep the band 3 stretched and to pull the band towards the support 9 when the winch 2 after having wound in a predetermined length of the band released it again. The band 3 is thus given a reciprocating motion along its entire length, the force of which in the direc-tion towards the winch is sufficient for e.g. moving one or more tree trunks or another load.
The holding member 5 must be ef~ectively locked to the band in the transport direction and release the band at the re-turn motion thereof, in order to have the load - the tree trunks -moved in the transport direction of the band.
The holding member 5 according to the embodiment shown ~ 16~24(~

in Figures 3-5 com~rises a cylindrical casing 12 of steel, on the underside of which a loop ll is a~ranged ~or connection of the object to be transported. The cylindrical casing - 6a -~ I6324() 12 is pro~ided with first 13 and second 14 tapered r-ecesses extending from the res~tive end portions of the casing 12 and in towards the central part of the casing, where the recesses 13 and 14 meet and form a free passage through the casing 12. This free passage has a substantially circular cross-section and has a diameter somewhat smaller than that of a locking member 16, e.g. a ball, placed therein.
The first tapered recess 13 is somewhat larger than the second recess 14 so that the locking ball 16 is given enough free space and for providing a suitable taper. This is important as the locking ~all 16 is intended to loc~
the band 3 extending through the holding mem~er 5 and the tapered recesses 13, 14 by wedge action. A part circular -end wall 17 is attached at ,the opening Or the first tapered recess 13 and is arranged to prevent the locking hall 16 from ~alling out of the holding member 5, The holding member 5 is provided with means for enabling a simple engagement and disengagement Or the holding mem~er 5 to and off the band 3. This is achieved by a longitudinal slot 18 extending along one side of the holding member 5, The holding mem~er is further provided with means,20 preventing the hand 3 from leaving the cylinder through the slot 18 in other cases than when a special releasing device is in its way. The slot 18 is according to this embodiment blocked by a spring-actuated 19 slide 21, which is displaceably arranged in the cylinder 12.

The front edge of the slide 21, as seen in the d;rection Or motion (to the right according to figure 5), is somewhat chamferred as well as the gu;ding edges 22 Or the ~lot 18~ This'facilitates the engagement and disengagement of the holding mem~er 5 on the band 3.

A releasing member 23 (figures 6-8) is preferablv arran~ed close to the driving end 3a of the band 3 for providing an automatic releasing of the holding member 5 and the l 16324(~

load connected thereto. The releasing memher 23 prefera~lv comprises a piece of sheet metal fixed to the band 3, e.g.
by means of a screw union or similar and compri~es a suhstan-tially flat taper portion 24 which i 8 arranged to partly extend into the slot o~ the holding memher 5 from thè
front and displace the slide 21 t~ an open position.
By the action of the taper portion 24 o~ the releasing member 23 the holding member 5 is d~splaced sideways (figure 8) andoff the band 3 whereby the holding member 5 and the load connected thereto can be taken care of manually Also other types of releasing members 23 càn be used, e.g.
they can be made of the same material as the band 3 and even be made integral with the band.

In figures 9-11 is shown a modified embodiment of the holding me~ber 5, which differs from the em~odiment described ahove by the fact, that the taper of the casing 12 and the angle of the surface 25 cooperating with the locking mem~er 16 is considerably steeper, at which a considerably worse wedging effect Or the locking member is achieved, but on the other hand a releasing of the band 3 without substan-tial tensile forces. The efrective wedging of the band in the holding member has been achieved by the fact that the band 3 is provided with fixed raised portïons 26, prefera~ly consisting of rubber blocks 27 arranged in the textile band 3. l~en a raised portion Or the band 3 contacts the locking member 16 an effective loc~ing of the hand is achieved without wedging the lockin~ member 16 against the inclined surface 25. Th;s is preferably curved in accordance with the radius of curvature of the locking ball 16.

Unlike the embodiment of figures 3-5 the slot 18 is per-manently open and the mem~er 20, which shall prevent the band 3 from leaving the holding member 5 throu~ the slot 18, comprises partly a curved end portion 28~ at one of the openings o~ the casing 12 and partly an extended portion q t lB324(~

29~ at which the slot 18 within this opening portion will be located at the lower edge of the outlet, The curved portlon 28 causes the band 3 to be curved in its longitudinal direction ~Yhen it leaves the holding member and thus obstructs the band from l'slipping" out through the slot 18.

There is only one moving part, namely the locking member 16, in this whole holding member construction, at which the reliabilit~ is very high even under very un~aavourahle conditions .

An even more simple variant o~ the holding memher is shown in figures 14 and 15 and comprises a casing 12 with a slot 18 and a load hook loop 11. The coupling together ~f the holding member 5 with the band 3 is made by way of locking member 16 fixed on the band and according to the embodiment shown consisting Or plastic or metal cones. The cone is so designed that its base is somewhat smaller than the inner diameter of the casing~ while the top Or the cone is tapered to the width and thickness of the hand. rleans 20 preventing the band from leaving the casing 12 can compris~ a special shaping of the slot 18, which according to the embodiment shown is slightly S-shaped. Also in this embodiment the band will he curved against the inside of the casin~ during its active transport phase, which means that the band ~
not leave the casin~ other~ise than when the releasing means forces the casing to this.

During the transport phase the band will take a position shown in figure 14~ at whic~ the base surface o~ the locking memher 16 contacts one of the end edges of the casing 12.
When the band 3 makes its return movement the locking member 16 will find its way through the casing 12 with its thillner end as is shown in figure 15.

Another way of preventing the band 3 from slipp-ng out Or the holding member 5 is to make the rubber blocks 27 so thick, that the band cannot slip out of the slot 18 b~ itself. ~he re~easing member must in this case be so arran~ed, that it ~ 16324(~

pulls oif the holdin~ membe~ ~o~ the band.

Tn the embbdiment accordiny to Figures 16 and 17 the holdin~ member ~s axially divided into two halves 30 and 31 con-nected with e~ch other by a hinge 32. The two halves 30 and 31 can by a locking means 20 be locked to each other. Said locking means compr~ses a number of locki~g pins 33 fixed in the upper half 30 and extending into corresponding recesses 34 in the lower half 31 when the halves are put together. The locking pins 33 are each provided with a recess 35 so located that an axle 36 can be pushed throu~h them and lock the pins 33. Also the axle 36 i~ provided with recesses 37, which by displacing the axle against the action of a spring 38 can be brought just in front of the pins 33, which by that are released. The axle 36 projects outside the inner end of thetapered end portion of the hoIding member and is intended to cooperate with a releasing member 23 fixed on the band 3. The releasing member is at its end facing the holding member designed with substantially the same taper as the tapered end of the holding member 5 and said releasing member 23 actuates the projecting end of the axle 36, so that the holding member opens and falls off the band.

In order to prevent that the locking member 16 is drop-ped when the holding member is opened, the locking member is se-cured to one of the holding member halves e.g. by means of a ball retainer 30 as is indicated in Figure 17.

The invention is not limited to the above described em-bodiment, but alternative embodiments, e.g. regarding structural members, are possible within the scope of the invention. Such an alternative embodiment (not shown) can comprise a device with double parallel pull bands between the supports. When one of the pull bands is moved forwards the other is moved backwards.
For enablin~ th~s course b~ motion a winch with double drums is arran~ed at one o~ the supports. The device i~ in this way giVen double capac~:ty or the second pull band can be used for transport in the opposite direction.

Claims (7)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A transport device comprising an elongate element, means for setting the elongate element into reciprocating movement in its longitudinal direction, at least one hold-ing member, for a load to be transported, releasably engag-able with said elongate element and being provided with a unidirectional locking member to lock the holding member to the elongate element in one direction of motion of the latter, characterised in that said elongate element is a flexible band having resiliently deformable raised surface portions for engaging the locking member, said raised sur-face portions being in the form of blocks located in and extending across the band at spaced locations from one another.

2. A transport device as claimed in claim 1, wherein the flexible band comprises two superposed layers and the blocks are disposed between said layers.

3. A transport device as claimed in claim 2, wherein the flexible band comprises an endless strip of material folded over on itself to provide said superposed layers.

4. A transport device as claimed in claim 1, 2 or 3, wherein the flexible band is made of a synthetic textile material.

5. A transport device as claimed in claim 1, 2 or 3, wherein the flexible band has a width considerably greater than its thickness.

6. A transport device as claimed in claim 1, 2 or 3, wherein the blocks are rubber.

7. A transport device as claimed in claim 1, 2 or 3, wherein said locking member is a ball which engages a re-spective raised portion and a tapered portion of the inner surface of the holding member so as to wedge the flexible band between its raised portion and the tapered portion of the holding member.