US3295882A - Grab device for timber - Google Patents

Description

Jan. 3, 1967 K. E. WALLBERG GRAB DEVICE FOR TIMBER 5 Sheets-Sheet 1 Filed March 1, 1965 w pmlam W Jan. 3, 1967 Filed March 1, 1965 K. E. WALLBERG GRAB DEVICE FOR TIMBER 5 Sheets-Sheet 2 QQmuQMZoL by w wz rew/ken. am

Jan. 3, 1967 K. E. WALLBERG GRAB DEVICE FOR TIMBER Filed March 1, 1965 3 Sheets-Sheet 5 cirvwwlm we m wwuzw United States Patent Office 3,295,882 Patented Jan. 3, 1967 3,295,882 GRAB DEVICE FGR TIMBER Karl Erik Wallberg, Bergnaset, Sweden, assignor to Kewacos Forsaljningsaktiebolag, Lulea, Sweden Filed Mar. 1, 1965, Ser. No. 436,726 Claims priority, appiication Sweden, Mar. 3, 1964, 2,562/ 64 6 Claims. (Cl. 29488) The present invention relates to a grab device for timber having a substantially U-shaped fork and a grab clamp pivoted to the upper shank of the fork and a piston engine to actuate the grab clamp.

In such grab devices it is difiicult and often impossible when loading timber on transport vehicles or Working benches to maintain a single or a small number of logs in horizontal position, because the gap of the fork, as a rule, is dimensioned for taking up greater loads.

One purpose of the invention is to eliminate this disadvantage, and according to the invention this is brought about in such a way that for grabbing a single or a small number of logs with a fork intended for greater loads a clamping link is connected close to the attaching point of the grab clamp so that when the grab clamp is brought into position to close the fork, the clamping link is turned toward the grab clamp, it being possible thus to reduce the gap of the fork.

The clamping link is preferably adapted to be retractable into the U-shaped bend of the fork at rest. The clamping link is preferably arranged to be actuated by the grab clamp only when the latter passes half of the fork depth. It is also suitable that the grab clamp and the clamping link are provided with cooperating ridges. To the free end of the clamping link a second link may be connected, the free end of which. runs in a guide attached to the fork. The clamping link is kept at rest in the fork by means of a tension spring.

The invention will be further described in the following in connection with the accompanying drawing, where FIGURE 1 shows a vertical side elevation of an embodiment of the grab device according to the invention, FIG- URE 2 shows a vertical side elevation of a second embodiment of the device, FIGURE 3 shows a part of the clamping link of both FIGS. 1 and 2 at rest and retracted into the fork and FIGURE 4 shows a part of the clamping link of both FIGS. 1 and 2 and as actuated by the grab clamp in clamping position.

According to FIGURE 1 a substantially U-shaped fork 1 is connected at the pivot 8 with a grab clamp 2, which is actuated by means of a piston engine 3. The grab clamp is provided with a ridge 4, which is arranged to engage a second ridge 6 on the clamping link 5. The clamping link is attached at the pivot 7 to the upper shank end of the fork near the pivot 8 of the grab clamp 2. A second link 9 is pivoted to the free end of the clamping link 5 with its free end carried in a guide 10 on the fork. 11 is a tension spring, which is tensioned to move the clamping link toward the fork and to keep the clamping link at rest retracted into the U-shaped bend of the fork. 16 is a log, which is held between the grab clamp 2 and the link 9 in horizontal position 12 and 13 are brackets for securing the grab device to a support such as a truck which is not shown.

In FIGURE 2 the fork 1 is similar to that shown in FIGURE 1 and is also provided with a grab clamp 2 and a clamping link 5. The link 9' however is different from the link 9 shown in FIGURE 1 and provides greater space for grabbing timber than in the device according to FIG- URE l. The free end of the link d is furnished with a slot 14, in which a tap 15 on the fork engages. In the retracted position of the clamping link 5 the link 9 takes the position marked with dash and dot lines. Three logs clamped between the link 9 and the grab clamp 2 in horizontal position are designated by 16. According to FIG- URE 3 the clamping link 5 is at rest and quite retracted in the fork 1, while the grab clamp 2 is in the initial or open position and the piston rod 17 is drawn into the cylinder 18.

According to FIGURE 4 the ridge 4 of the grab clamp 2 has actuated the ridge 6 of the clamping link 5 and turned the clamping link outwards toward the grab clamp.

The device is of course not confined to the embodiments shown in the drawing but may be altered within the scope of the invention as defined in the appended claims. Thus the clamping link may for instance be formed in one piece so that a log may be grabbed by the grab clamp and the clamping link as by shears and in this way secured in horizontal position.

I claim:

1. A grab device for timber comprising a substantially U-shaped fork which in its normal position has an upper and a lower arm and an open and a closed side, a first pivot adjacent to the free end of said upper arm, a grab clamp connected adjacent its upper end to said first pivot, a piston engine connected between said fork and said grab clamp and adapted to swing said grab clamp through said open side, a second pivot on the upper arm of said fork adjacent to said first pivot, a clamping link connected adjacent to its upper end to said second pivot and means connecting said grab clamp and said clamping link whereby the free end of the latter is moved forwardly toward said open side when the free end of the former moves rearwardly through said open side into the space between said upper and lower arms.

2. A grab device as defined in claim 1, comprising means tending to hold the free end of said clamping link adjacent to said upper arm of said fork.

3. A grab device as defined in claim 2, in which said means tending to hold the free end of said clamping link adjacet to said upper arm of said fork is a spring.

4. A grab device as defined in claim 1, in which said means actuates said clamping link to move forwardly only when said grab clamp moves inwardly farther than half the depth of the space between said upper and lower arms.

5. A grab device as defined in claim 1, in which said means consists of cooperating ridges adjacent the pivoted ends of said grab clamp and said clamping link.

6. A grab device as defined in claim 1, comprising a third pivot adjacent to the free end of said clamping link, a second link connected adjacent one end thereof to said third pivot and a guide on said fork for the other end of said second link.

References Cited by the Examiner UNITED STATES PATENTS 3,119,637 1/1964 Eaves 294104 X 3,165,345 1/1965 Gardner 294-104 X 3,165,348 1/1965 Keski-talo 29488 3,194,421 7/1965 Lull 2 l4l47 FOREIGN PATENTS 25,486 6/1952 Finland.

HUGO O. SCHULZ, Primary Examiner.

Claims (1)

1. A GRAB DEVICE FOR TIMBER COMPRISING A SUBSTANTIALLY U-SHAPED FORK WHICH IN ITS NORMAL POSITION HAS AN UPPER AND A LOWER ARM AND AN OPEN AND A CLOSED SIDE, A FIRST PIVOT ADJACENT TO THE FREE END OF SAID UPPER ARM, A GRAB CLAMP CONNECTED ADJACENT ITS UPPER END TO SAID FIRST PIVOT, A PISTON ENGINE CONNECTED BETWEEN SAID FORK AND SAID GRAB CLAMP AND ADAPTED TO SWING SAID GRAB CLAMP THROUGH SAID OPEN SIDE, A SECOND PIVOT ON THE UPPER ARM OF SAID FORK ADJACENT TO SAID FIRST PIVOT, A CLAMPING LINK CONNECTED ADJACENT TO ITS UPPER END TO SAID SECOND PIVOT AND MEANS CONNECTING SAID GRAB CLAMP AND SAID CLAMPING LINK WHEREBY THE FREE END OF THE LATTER IS MOVED FORWARDLY TOWARD SAID OPEN SIDE WHEN THE FREE END OF THE FORMER MOVES REARWARDLY THROUGH SAID OPEN SIDE INTO THE SPACE BETWEEN SAID UPPER AND LOWER ARMS.

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