US3608950A

US3608950A - Arrangement at load carrier

Info

Publication number: US3608950A
Application number: US865253A
Authority: US
Inventors: Karl-Ivan Westbrand
Original assignee: Ostbergs Fabriks AB
Current assignee: Ostbergs Fabriks AB
Priority date: 1968-10-11
Filing date: 1969-10-10
Publication date: 1971-09-28
Anticipated expiration: 1988-09-28
Also published as: FI47567B; FI47567C; SE318824B; DE1950948B2; DE1950948A1; DE1950948C3; NO130148B

Abstract

A load carrier comprises two grip arms pivotally mounted at their lower ends and so foldable from and towards each other that they overlap one another, each grip arm having a link mounted thereon at a point spaced from the axis of rotation of the arm. The other ends of the links are mounted slidably along paths each extending from the vicinity of the axis of rotation of the associated arm and directed substantially to the axis of rotation of the opposite arm, the respective paths for said other ends of the two links so extending side by side that when the grip arms swing together the links intersect one another providing a fourcorner gripping space.

Description

United States Patent Karl-Ivan Westbrand ARRANGEMENT AT LOAD CARRIER 3 Claims, 1 Drawing Fig.

US. Cl

294/106, 294/115, 214/653 Int. Cl B66c 1/42 Field of Search 294/672 C,

References Cited Primary Examiner--Evon C. Blunk Assistant Examiner-Johnny D. Cherry Attorney-Pierce, Scheffler & Parker ABSTRACT: A load carrier comprises two grip arms pivotally mounted at their lower ends and so foldable from and towards each other that they overlap one another, each grip arm having a link mounted thereon at a point spaced from the axis of rotation of the arm. The other ends of the links are mounted slidably along paths each extending from the vicinity of the axis of rotation of the associated arm and directed substantially to the axis of rotation of the opposite arm, the respective paths for said other ends of the two links so extending side by side that when the grip arms swing together the links intersect one another providing a four-corner gripping space.

ARRANGEMENT AT LOAD CARRIER This invention relates to an arrangement at a load carrier comprising two grip arms pivotally mounted at their lower end and so foldable from and towards each other that they overlap one another.

Conventional load carriers of said clamping type show the disadvantage of being incapable safely to grip around wood loads of a very restricted volume, in extreme cases single logs. This incapability has its reason, of course, in the distance between the mounting points of the grip arms at the ends of the supporting beam, which distance necessarily has to be relatively large, in combination with the fact that the position of the grip arms when they are folded together to the maximum possible extent is limited for construction reasons.

This disadvantage is eliminated in that the arrangement ac cording to the invention is characterized as follows. On each grip arm, in a point spaced from the axis of rotation of the arm, one end of a link is mounted the other end of which is mounted slidably along a path extending from the vicinity of the axis of rotation of the associated arm and directed substantially to the axis of rotation of the opposite arm, the respective paths for said other end of the two links so extending side by side that the links, when the grip arms swing together, can intersect one another and from below reduce the grip volume of the arms to a minimum value for rendering possible a safe gripping also of small wood dimensions.

The invention is described in greater detail in the following, with reference to the accompanying drawing the only FIGURE of which shows a vertical view of an embodiment of the invention.

The supporting beam 1 forming the structure of the load carrier is carried by the load vehicle in question via a rotating track 2 and a hinge connection 3, so that the beam 1 and thereby the entire load carrier can be swung both in the horizontal plane and in the vertical plane extending through the longitudinal direction of the wood load, Hereby the load held safely clamped is given universal mobility in relation to the carrying vehicle and thereby is easy to operate even when driving in a difficult wood terrain. In the vicinity of each end of the beam l, a grip arm 4 and 5, respectively, are pivotally mounted at one end about the point 6 and 7, respectively, in such a manner, that the grip arms mutually are displaced in axial direction so as to render possible their overlapping when the arms are being folded together. Furthermore, a hydraulic means 8 and 9, respectively, are placed in a usual way between a point 10 and 11, respectively, at each end of the beam 11 (outside the mounting points of the grip arms) and a

point

12 and 13, respectively, located closer to the center on the adjacent grip arm 4 and 5, respectively. The FIGURE shows by uninterrupted lines the arrangement with the grip arms in an intermediate position, for which position the arm points touch the central vertical plane.

In the embodiment shown of the invention an auxiliary arm in the form of a curved link are connected to each grip arm 4 and 5, respectively, with one end in a point 15 located close to the center of grip arm 4 (for reason of clearness only one link 14 is shown). The other end of link 14 is provided with a lateral pin 16 engaging with a horizontal slot 17 cut into the beam 1, said slot according to the FIGURE extending on a level higher than the mounting points 6 and 7 of the grip arms. A corresponding slot for the other auxiliary arm or link is provided on the opposite side of beam 1. In this embodiment the mounting and curvature of the link 14 so are chosen that in the position shown by uninterrupted lines (in which position the grip arm points touch each other) each grip arm, such as 4, and the curved inner outlines ofassociated link 14 coincide.

In the position I shown by dash-dotted lines, in which the grip arm 4 is swung out to its maximum extent (and in the corresponding outer position of grip arm 5) the inner outline of the auxiliary arm or link 14 is located inside of the inner outline of arm 4 (and 5), and the lateral pin 16 of the link 14 is located at the end of the slot 17 in beam l. The loading takes place, and the hydraulic means 8 and 9 are fed so that the arms 4 and 5 are caused to swing inwards by extension of the rams of the hydraulic means. If the cross section of the load is smaller than the substantially circular surface defined by the inner outline of the grip arms 4 and 5 and of the supporting beam 1 in the position II shown by uninterrupted line, the grip arms 4 and 5 overlap one another.

From this moment, the inner outline oflink 14 (as well as of the opposite link) moves past the inner outline of grip arm 4 (and 5), because the lateral pin 16 of link 14 owing to the inward swing movement of grip arm 4 is forced to slide inwards in slot 17 of the supporting beam ll. [in the final position III of grip arm 4 the lateral pin 16 of the link 14 has slided all the way to the opposite end of slot 17, for which position the grip volume defined by the inner outline of the grip arms and links has become very limited, as can be seen in the FIGURE. At a tested construction according to the embodiment shown it was found that the grip volume could be varied from wood loads of about 2 m? total area to single logs of about 6-inch diameter.

The opening of the grip arms from their position III in which they are swung inwards to the greatest possible extent, is effected by feed of the hydraulic means 8 and 9 in reverted direction whereby the grip arm 4 (and 5) is caused to swing outwards again and thereby takes along link l4 so that the lateral pin 16 of said link again slides in the slot l7 and arrives at the right-hand end thereof (in the FIGURE) when the starting position I again has been assumed.

The invention is not restricted to the embodiment shown, but different modifications thereof within the scope of the invention can be imagined. The hydraulic control, thus, can be arranged in a different way, for example by moving the hydraulic means 8 (and 9) to a position for directly actuating the link 14, or by completing the hydraulic means shown with a hydraulic means for actuating the link and coordinating the feed of the latter with that of the first hydraulic means. In the latter case it is further obvious that thelink 14 need not be a rigid unit, but may be articulated or be a chain or rope. The slot (or bar) of the supporting beam and the lateral pin of the link, of course, can be replaced by a flange on the beam side and, respectively, a yoke at the link end enveloping the beam side. It is not necessary, either, that the slot or flange of the beam is straight and horizontal, but it can be inclined and/or slightly curved.

What I claim is:

1. In a load carrier for tree trunks and other elongated objects having a greatly varying thickness, comprising two upwards extending and curved grip arms having their lower ends pivotally mounted in a spaced relationship at a load support for rotation in separate but adjacent vertical planes, and a hydraulic jack connected between each arm and said support for driving the grip arms between a widely open position and an overlapping position, the improvement which consists of the provision of two links, each having its one end pivoted at the intermediate portion of a respective arm and its other end terminated by a slidable member;

an essentially straight guide member extending between the respective regions of the pivotal axes of said arms and having a different sliding path for guiding each of the two slidable members,

the links being formed to be substantially completely covered by the arms when these are in the open position, while the links, when the jacks are actuated for closing the arms, are brought along by the arms while pushing their sliding members along the respective sliding paths and crossing each other after the arms having reached their overlapping position,

whereby an object dropped down between the grip arms in their originally open position is rigidly fixed in a fourcomer gripping space defined by the crossing lower edges of the two grip arms and the crossing upper edges of the two links.

2. A load carrier according to claim 1, wherein the links are curved in the same direction as the grip arms.

3. A load carrier according to claim I, wherein the sliding member of each link comprises a lateral pin, and the guide member is a bar having grooves at opposite sides for receiving the respective pins of the links.

Claims

1. In a load carrier for tree trunks and other elongated objects having a greatly varying thickness, comprising two upwards extending and curved grip arms having their lower ends pivotally mounted in a spaced relationship at a load support for rotation in separate but adjacent vertical planes, and a hydraulic jack connected between each arm and said support for driving the grip arms between a widely open position and an overlapping position, the improvement which consists of the provision of two links, each having its one end pivoted at the intermediate portion of a respective arm and its other end terminated by a slidable member; an essentially straight guide member extending between the respective regions of the pivotal axes of said arms and having a different sliding path for guiding each of the two slidable members, the links being formed to be substantially completely covered by the arms when these are in the open position, while the links, when the jacks are actuated for closing the arms, are brought along by the arms while pushing their sliding members along the respective sliding paths and crossing each other after the arms have reached their overlapping position, whereby an object dropped down between the grip arms in their originally open position is rigidly fixed in a four-corner gripping space defined by the crossing lower edges of the two grip arms and the crossing upper edges of the two links.

3. A load carrier according to claim 1, wherein the sliding member of each link comprises a lateral pin, and the guide member is a bar having grooves at opposite sides for receiving the respective pins of the links.