DK152921B - Automatic telescopic lock for locking together the parts of a telescopic mast - Google Patents

Description

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DK 152921B

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The present invention relates to an automatically acting telescopic lock for interlocking slidable portions of a telescopic mast as set forth in the preamble of claim.

5 Tower cranes are most often made up of several telescopic mast parts which are mounted at the work site due to transport restrictions when moving from place to place. The telescoping is often hydraulic and requires a somewhat less compressive force than the operating load. In order to take up the operating load, the mast parts are provided with locks, which are normally placed at the bottom of the inner mast part. The locking posts are then pulled out over the outermost beams by means of a spring or weight, and pushed into the unlocked position by means of a guide rail mounted on the outermost.

15 When rusting or icing this system, the force of the spring or weight may be too small to overcome the resistance, thereby risking that the locking posts will not project sufficiently beyond the outermost carrier rails with risky malfunctions as a result.

The object of the invention is to provide an automatically acting lock by means of which the uncertainty of the operation of the lock can be avoided. This is achieved by the features of claim 1.

25 Locking of the pallets with a support beam takes place in a controlled manner such that the locking pallets mounted on the inner mast part pass the carrier beam downwards a little way past the locking position, after which the inner mast part is lowered and the locking pawls engage.

30 Release occurs by lifting the inner mast part approx. twice as high above the support beam as when locking took place. Thereby the locking pawls are retracted by means of the guide rail and the movement can continue upwards or downwards.

35 When lifting the inner mast part, the locking pawls will briefly move beyond the support beam and thereafter 2

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DK 152921B

utes are quickly withdrawn again. When the mast is telescoped down, the locking posts remain in the free position. Hereby it is achieved that the locking pawls will either be in the fully activated state, that is, completely beyond the support beam, or completely in the unactivated state, ie pulled completely free of the outer mast.

The telescopic lock according to the invention will be described below in accordance with the drawing, fig. 1 is a front view of a system of guide rails mounted on a control bracket mounted on the outer part of a telescopic mast; and FIG. 2 shows the lock according to the invention with the bracket plate mounted on an outer mast part with support beam as seen from above.

On a bracket plate (a) a system 15 of guide rails (e, f, g) is welded. In addition, a guide rail (b) is movably arranged on the plate, the movement of which is controlled by a spring (d) and a stop block (c). FIG. 2 shows the bracket plate (a) mounted on an outer mast part with a support beam (s). Furthermore, there is mounted on the inner mast part shown a 20 or more locking pawls (p) inserted in a holder (s). The locking pawl (p) can be moved back and forth by means of a connecting rod (n). The movement of the pawl (s) (p) itself is directed by a guide rod (k) which is hingedly connected to the connecting rod (n) and carries at its one end a guide roll (h). The movement of the guide rod is limited by a guide (i) arranged on the inner mast part and a spring (m) causes the guide rod (k) to move to and remain in one of its two end positions, where the drawn right position of the guide roller (h) corresponds to locking and left 30 position for release of pawls (p). The guide roller (h) is guided in the control console (a) as follows: when the roller (h) comes down from its normal left position during the telescoping of the inner mast part, and if the pawls (p) have just passed the support beam (s), the roller ( h) of the movable guide rail (b) to the right. By means of the pull spring (d) and the stop block (c) the latter is held in its drawn position. The roller (h) is guided therefrom to the right of the fastener.

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standing oblique guide rail (s), unless the spring (m) slightly causes the roller (h) to snap completely against the right stop of the guide (i). If the inner mast part is now held in this position, it is lowered a bit 5 until the pile (s) (p) rests on the support beam (s).

If the inner mast part has not been telescoped high enough for the guide roller (h) to reach its right stop, but is positioned in the middle, the lowering will cause the guide roller to be guided by the guide rail (f) with two inclined parts 10 either to the right , where it locks as intended, or to the left where the lowering continues until the operator detects the fault. In this case, the inner mast part is moved upwards again. If the mast is not to be held in this position, but just pass the ledge on the way up, the guide roller (h) is driven through the control console (a), whereby the guide rail (e) first controls the pawls (p) in the locking position and a further inclined guide rail ( (g) immediately release them. The roller (h) is thus forced to its starting position to the left and held there by the spring (m). Passing a ledge on the way down takes place in the following way: the guide roller (h), which is in the left starting position, pushes the movable guide rail (b) to the right by overcoming the force of the spring (d). Once the roller has passed the guide rail (b), the latter will be pulled back into place by the spring (d).

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Claims (1)

Lock according to claim 1, characterized in that the guide rails are designed so that at the end of the first part of the movement path they form an extension (f) of the width of the movement path. 30 35