This invention relates to a pole step; more particularly, it concerns a pole step to be mounted on a tubular mast, wherein several pole steps are attached to the mast in a spaced-apart manner to enable access to the upper portions of the mast, and wherein the pole step comprises a step body, the pole step, during mounting, being arranged to be inserted into an opening in the mast wall, and the step body afterwards being secured to the mast. The invention also comprises a procedure of attaching a pole step to a tubular mast.

Background of the invention

Conventionally, pole-climbing shoes have been used for accessing the upper portions of a wooden mast. When masts that are made from metal or composite materials are used, this is not possible.

More often than not, composite masts are formed as cylindrical or conical pipes and usually without or with difficult access on the inside of the mast.

It is known to provide the mast with pole steps that are distributed along the mast, usually in drilled holes in the mast wall. The pole steps may consist of metal rods extending diametrically through the mast and projecting on both sides thereof.

A pole step that has become relatively widely used, is provided with an L-shaped hook that is inserted through a bore in the mast wall and placed in abutment against the inside of the mast wall above the bore. A nut on the outside of the mast wall is tightened to secure the pole step.

Experience has proved that pole steps of this kind are apt to come loose if they are subjected to impacts and forces acting in the opposite direction to what they are designed for.

The invention has for its object to remedy or reduce at least one of the drawbacks of the prior art or at least provide a useful alternative to the prior art.

The object is achieved through the features that are specified in the description below and in the claims that follow. The invention is defined by the independent claims. The dependent claims define advantageous embodiments of the invention.

Description of the invention

The pole step and the procedure according to the invention overcome the known problems by ena- bling abutment of the pole step on the inside of a mast wall both above and below the opening where the pole step is installed. In its simplest form, the pole step comprises an unbalanced pawl which is rotated into the desired position by means of gravity after it has been moved through the opening. When the pole step is then tightened, the pole step can absorb forces in any direction without loosening. In a first aspect, the invention relates more specifically to a pole step to be mounted in an opening in a mast wall with an outside and an inside belonging to a tubular mast, the pole step comprising a rotatable step body with a longitudinal axis, an axially displaceable locking element, an end portion with a stop and a rotatable unbalanced pawl, the pawl having a bevel arranged to rest supportingly against the stop in a guiding and unlocked position when the step body is in an inactive position so that the pawl and the step body may be moved into or out of the opening of the mast wall. The pawl, when having been inserted through the opening, may be positioned in a locked position perpendicular to the longitudinal axis of the step body by means of the gravitational force, by rotating the step body from the inactive position to an active position. In the locked position, the pawl rests supportingly against the inside of the mast wall on two sides of the step body so that the step body is clamped to the mast wall when the locking element is tightened. The pawl can be brought back into the guiding and unlocked position by rotating the step body from the active to the inactive position.

A pole step for mounting on a tubular mast, wherein, during mounting, an end portion of the pole step is arranged to be inserted into an opening in a mast wall, and wherein the step body is then secured to the mast by a locking element on the pole step being displaced axially against the mast wall, is described as well, the end portion of the pole step being provided with a lock which, after having been moved at least partially through the opening, is arranged to be activated between the locked position and the unlocked position by means of the gravitational force.

Several pole steps, each comprising a step body, may be attached to the mast in a spaced-apart manner to enable access to the upper portions of the mast.

The lock comprises an unbalanced rotatable pawl which is rotatably attached to the step body.

The step body may include a slot arranged to accommodate the pawl in the unlocked position.

The pawl may be formed with an oblong displacement slot to enable combined rotation and axial displacement of the pawl relative to the pole step. The slot may be formed in such a way that it is possible to rotate the pawl by means of a tool from the outside of the mast. The slot may, for example, be so long that it is open to the outside of the mast. This may be practical if the pawl is difficult to rotate.

The pawl may be formed with a bevel arranged to rest against a stop in the step body when the step body has been rotated into an active position so that the longitudinal axis of the pawl coincides with the longitudinal axis of the pole step. Thereby the pawl may take a guiding position so that the lock and the pawl may, in a simple manner, be moved into or out of the opening in the mast wall. By a horizontal insertion of the step body, the pawl will have a horizontal position. When the lock of the step body has been moved through the mast wall, the step body is rotated into an active posi- tion and the pawl is rotated, because of the gravitational force, into a vertical position.

When the step body is being dismounted, the step body is rotated from the active position into the inactive position so that the pawl takes the horizontal position and the pole step can be pulled in a simple manner out of the mast wall.

In a second aspect, the invention relates more specifically to a procedure for mounting a pole step on a tubular mast, wherein several pole steps are attached in a spaced-apart manner to the mast to enable access typically to the upper portions of the mast, and wherein the pole step comprises a step body, the step body, during mounting, being arranged to be inserted into an opening in the mast wall, and the step body then being secured to the mast, the procedure being characterized by comprising:

- positioning the lock relative to the step body before the step body is inserted into the opening;

- letting the lock be activated, by means of gravity, between the unlocked position and the locked position; and

- securing the pole step to the mast.

If the mast is in a non-vertical position during the mounting work, the procedure may further in- elude:

- bringing the pole step into a position in which the lock is activated, by means of gravity, between the unlocked position and the locked position; and

- bringing the pole step into the desired position relative to the mast before the pole step is secured to the mast. The pole step may, for example, be inserted partially through the opening until the pawl is rotated into the locked position, after which the pole step is rotated around its longitudinal axis until it takes the desired direction relative to the mast.

The procedure often includes rotating the pawl, by means of gravity, between a horizontal position and a vertical position after the lock has been inserted into the opening. In a preferred embodiment, the lock comprises a rotatable pawl having unequal masses on two sides of the centre of rotation. By holding the pole step in a position in which the pawl has the possibility of being rotated or displaced, it may, by means of gravity, switch between the unlocked position and the locked position.

By the very fact of the invention not being dependent on spring-biasing, for example, it is easy to detach the pole step, for example if it is to be removed to prevent unintended access to the mast.

However, in some cases, it may be practical to use biasing in the locking direction, for example by a spring.

The device and the procedure according to the invention solves the task of attaching the pole step to the mast in a simple and cost-effective manner and thereby solves a long-felt problem.

In what follows, an example of a preferred embodiment and procedure is described, which is visualized in the accompanying drawings, in which:

Figure 1 shows a side view of a mast part in which pole steps according to the invention have been installed;

Figure 2 shows a horizontal section of the mast of figure 1 ;

Figure 3 shows a side view, on a larger scale, of a pole step which is being inserted into an opening in the mast;

Figure 4 shows the same as figure 3, but after the pole step has been inserted sufficiently for the lock to be activatable;

Figure 5 shows the pole step after the pole step has been secured according to the invention to the mast;

Figure 6 shows a horizontal view of the pole step of figure 5;

Figure 7 shows a side view of a pole step with a pawl provided with a bevel resting against a stop on the pole step, and the pole step being in an inactive position; and

Figure 8 shows the same as figure 7, but the pole step has been inserted and rotated into an active position so that the lock may be activated .

In the drawings, the reference numeral 1 indicates a pole step which is attached to a mast 2, here in the form of a hollow composite mast. In figure 1 is shown a pattern of pole steps 1 that are arranged on the mast 2 to provide easy access to the upper portion, not shown, of the mast 2. In this preferred exemplary embodiment, the pole step 1 comprises a step body 4, see figure 3, in which a step portion 6 which is outside the mast 2 in a position of application is arranged to absorb forces from a person, not shown, climbing the mast. A hook 8 on the outer end of the step portion 6 is arranged to prevent inadvertent slipping on the step portion 6.

In its opposite, inner end portion 14, the step body 4 is provided with external threads 10, see figure 3 to 6. A central, diametric, through slot 12 extending inwards from the inner end portion 14 is arranged.

A pawl 16 which is rotatable around an axle 18 is arranged in the slot 12. The axle 18 is preferably perpendicular to the slot 12 and the longitudinal axis 20 of the pole step.

The slot 12, the axle 18 and the pawl 16 constitute a lock 22 here. A shim 24 and a locking element 26, shown as a nut here, have been moved in over the threads 10.

The mast 2 is tubular and has a mast wall 28. Openings 30 have been drilled with defined spac- ings.

When a pole step 1 is to be mounted on the mast 2, the step body 4 of the pole step 1 is inserted into the opening 30 while the pawl 16 takes an unlocked position, as it has been righted in the direction of the longitudinal axis 20 of the pole step 1 , see figure 3.

When the pole step 1 has been inserted sufficiently through the opening 30, the pawl 16 is free to rotate around the axle 18. As the pawl 16 has a larger mass on one side of the axle than on the opposite side, it will, because of gravity, be rotated into taking a more vertical position, see figure 4.

When the locking element 26 is tightened, the pawl 16 is clamped against the inside of the mast 2 while the shim 24 is clamped against the outside 29 of the mast 2 whereby the pole step 1 is secured to the mast 2, see figures 5 and 6.

Figures 7 and 8 show an embodiment of the pole step 1 , in which the pawl 16 is formed with a bevel 32 arranged to rest against a stop 34 in the step body 4 when the pole step 1 has been rotated into an inactive position as shown in figure 7. In the inactive position, the longitudinal axis 36 of the pawl 16 coincides with the longitudinal axis 7 of the pole step 1 so that the pawl 16 takes a guiding position. The lock 22 may then be moved through the opening 30 of the mast wall 28 in a simple manner.

Figure 8 shows the pole step 1 rotated into an active position in which the pawl 16, because of gravity, is rotated into taking a more vertical position so that the pole step 1 may be firmly locked to the mast wall 28.

It should be noted that all the above-mentioned embodiments illustrate the invention, but do not limit it, and persons skilled in the art may construct many alternative embodiments without depart- ing from the scope of the attached claims. In the claims, reference numbers in brackets are not to be regarded as restrictive. The use of the verb "to comprise" and its different forms does not exclude the presence of elements or steps that are not mentioned in the claims. The indefinite article "a" or "an" before an element does not exclude the presence of several such elements. The fact that some features are indicated in mutually different dependent claims does not indicate that a combination of these features cannot be used with advantage.