GB2327057A

GB2327057A - Pole turning apparatus

Info

Publication number: GB2327057A
Application number: GB9714401A
Authority: GB
Inventors: Walter Snaith Sample; Raymond James Shankland
Original assignee: CLYDESDALE Ltd; SAHLINS CLYDESDALE Ltd
Current assignee: CLYDESDALE Ltd; SAHLINS CLYDESDALE Ltd
Priority date: 1997-07-08
Filing date: 1997-07-08
Publication date: 1999-01-13
Also published as: GB9714401D0

Abstract

When installing new telegraph poles, to rotate a vertical pole 24 in order to align the cross-arm insulators on the pole with those of adjacent poles, a strap device is used. A strap 10 connected near an end of a telescopic arm 4 of the device is placed around the circumference of the telegraph pole 24, and the free end of the strap 10 is threaded through the inside of a bracket 12 and pulled tight around the pole. Arm 4 is then held in an approximately horizontal position with a plate 8 trapping the free end of the strap 10 against pole 24. Arm rotated to rotate the telegraph pole 24.

Description

POLE TURNING APPARATUS The present invention relates to a device and method for rotating telegraph poles.

When installing new telegraph poles, it is usual to connect the cross-arms and insulators to a pole while it is lying along the ground, and then to use a crane to place the pole in an upright position in a pre-dug hole.

The pole is then set in this position by filing in the hole. Before a pole is set in its final position, however, it is necessary to rotate it to align the crossarm and insulators with those of the adjacent poles so that the cables can be passed therebetween.

In one known method of rotating a pole to its final position, a chain connected at one end to a lever arm is wrapped around the pole and the free end of the chain reconnected to the level arm by means of a hook arrangement provided on the arm for receiving a link of the chain. A plurality of spikes are provided at one end of the lever arm, which engage the pole when the arm is held in a horizontal position. By rotating the lever arm around the pole, the spikes are caused to dig into the pole and the chain to grip the circumference of the pole.

In this way, the pole can be rotated by pushing the lever arm around the pole.

Considerable force is necessary to rotate the pole since firstly, its weight is in the range 150Kg to 1400Kg, and secondly, it is already partially embedded in the ground (in order to maintain it in the vertical position). It is therefore usual for a workman to push or pull the lever arm while at the same time using his body weight to apply force as well. A winch may also be used to pull the lever arm.

A problem which has now been identified with the conventional technique described above is that the pole suffers damage during the rotation operation. In particular, the surface of the pole is splintered, and the splinters may become embedded in cattle, or other animals, which rub themselves against the pole. This is a particular problem since the poles are treated with preservative, such as creosote, which can infect the animal, reducing the price of the animal's carcass when sold for meat.

The present invention has been made with the above problems in mind.

According to the present invention, there is provided a device for rotating telegraph poles, comprising an arm having connected thereto a strap for passing around the telegraph pole, the arm being arranged to hold the free end of the strap so that movement of the arm around the telegraph pole causes the strap to grip the pole and the pole to rotate, without the strap tearing.

The present invention also provides apparatus for turning a telegraph pole, comprising a strap for encircling the telegraph pole and an arm for retaining the ends of the strap while the arm is moved to rotate the pole.

The invention also provides a method of turning telegraph poles, comprising passing a strap around a telegraph pole, retaining the ends of the strap using an arm, and moving the arm so as to turn the telegraph pole.

These features provide the advantage that a telegraph pole can be rotated using a smooth material in the form of a strap to grip the pole.

Preferably, the arm retains the strap such that force on the strap is distributed across the majority of the width of the strap, preferably the full width. (It has been found that if the strap has the form of a belt, with holes at one end for engaging a hook on the arm in a similar way to that in which a link of the chain in the prior art apparatus is engaged, then the force from on belt is applied via the holes, and the strap tends to tear.) An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 shows a device for turning telegraph poles; and Fig. 2 shows a cross-section through the device of Fig.

1 and a telegraph pole when the device is in use.

Referring to the drawings, a device 2 for rotating telegraph poles comprises a telescopic arm 4 having a rubber handle 6 at one end thereof and a curved plate 8 welded to the other end. Arm 4 has an unextended length of approximately 85cm, and an extended length of approximately 130cm. Arm 4 is made so as to withstand the forces imparted on it when it is used to turn telegraph poles. In this embodiment, arm 4 is therefore constructed from high-tensile seamless steel tube having a wall thickness of 8mm. Likewise, plate 8 is constructed from high-tensile steel and has a thickness of 12mm.

A strap 10 is connected near the end of arm 4 which has the plate 8. The strap 10 is connected to arm 4 via a bracket 12 comprising side plates 14 and a connecting bolt 16. The bracket 12 is pivotally connected to arm 4 via a bolt 18, for pivotal movement about axis 20. The strap 10 is attached to bracket 12 by passing bolt 16 through a loop 22 in the belt. The loop is formed by stitching two lengths of the strap together.

The strap 10 and bracket 12 are constructed to withstand a load of at least 6000Kg in an "as new" condition. This is achieved in this embodiment by using a strap made from polyester webbing with a width "D" of 5cm and a thickness of approximately 3mm. The width of strap 10 is substantially the same as the width "W" of plate 8.

To allow the strap 10 to encircle telegraph poles of different diameters, the length of the strap from bolt 16 to its free end is approximately 150cm.

Referring to Fig. 2, in use, strap 10 is placed around the circumference of a telegraph pole 24. The free end of the strap 10 is threaded through the inside of bracket 12 (that is, between bolt 16, side plates 14 and arm 4) and pulled tight around the pole. Arm 4 is then held in an approximately horizontal position with plate 8 trapping the free end of strap 10 against pole 24.

Passing the free end of strap 10 inside bracket 12 facilitates the trapping of the strap since strap 10 is prevented from slipping from between pole 24 and plate 8 while the strap is pulled tight around the pole. Arm 4 is then extended to its maximum length and force is applied to handle 6 to move the arm 4 around the circumference of telegraph pole 24 in the direction of arrow 26. As the arm is rotated, strap 10 is maintained in contact with pole 24 since its free end is trapped against pole 24 by plate 8, and the strap cannot therefore slip. As more force is applied to arm 4 in the direction of arrow 26, more force is applied to trap strap 10 between plate 8 and pole 24. Since strap 10 has a width "D" substantially the same as the width "W" of plate 8, the force is distributed across the full width of strap 10. The curved shape of plate 8 ensures that a smooth part of the plate, rather than a sharp edge, always contacts the strap 10. For example, if strap 10 is not pulled completely tight around pole 24 before arm 4 is moved, then some initial rotation of arm 4 and plate 8 about the point at which plate 8 contacts strap 10 will occur until the slack in strap 10 has been taken up.

Once the slack in strap 10 has been taken up, further rotation of arm 4 in the direction of arrow 26 will rotate telegraph pole 24 in the direction of arrow 28.

The pivotal connection of bracket 12 to arm 4 facilitates the operation described above. For poles of conventional diameter, when strap 10 is pulled tight around the pole, bracket 12 rotates to the position shown in Fig. 2 and, as arm 4 is moved around telegraph pole 24 in the direction of arrow 26, the free end of strap 10 is trapped between plate 8 and the end of the loop 22 of strap 10 which is passed around bolt 16 (as shown in Fig. 2). This provides an additional mechanism to prevent strap 10 slipping as arm 4 is moved around the telegraph pole.

A number of modifications are possible to the embodiment above.

For example, the width "W" at plate 8 need not be substantially the same as the width "D" of strap 10. The width "W" of plate 8 determines the width of strap 10 across which force is distributed. Accordingly, a wider strap may be used since this will be able to withstand the force applied across only a part of its width.

Claims

1. A device for rotating a telegraph pole embedded in the ground about a substantially vertical axis along the length of the pole, comprising an arm having connected thereto one end of a strap for encircling the telegraph pole, the arm having a part at one end thereof arranged to trap the free end of the strap against the pole after the strap has been passed around the pole and when the arm is held substantially perpendicular to, and is rotated about, the rotation axis, such that rotation of the arm about the axis rotates the telegraph pole about the axis.

2. A device according to claim 1, wherein the part for trapping the free end of the strap is arranged to distribute the force on the strap across the majority of the width of the strap.

3. A device according to claim 2, wherein the part for trapping the free end of the strap has a surface of substantially the same width as, or greater than, the width of the strap.

4. A device according to any preceding claim, wherein the part for trapping the free end of the strap has a convex curved surface.

5. A device according to claim 4, wherein the part for trapping the free end of the strap comprises a convex plate welded to the arm.

6. A device according to any preceding claim, wherein the strap is connected to the arm via a moveable mount.

7. A device according to claim 6, wherein the mount is arranged on the arm such that, in use, the mount moves to a position in which it, or the strap thereon, contacts the free end of the strap.

8. A device according to claim 6 or claim 7, wherein the mount is pivotally connected to the arm.

9. A device according to any preceding claim, wherein the arm has a length of at least 75cm.

10. A device according to any preceding claim, wherein the strap has a length of at least 70cm.

11. A device according to any preceding claim, wherein the strap and its connection to the arm can withstand a load of 6000Kg.

12. A device for rotating a telegraph pole standing in the ground, comprising a strap for passing around the telegraph pole, and an arm for retaining the strap against the telegraph pole as the arm is moved about the rotation axis to turn the telegraph pole, without the strap tearing.

13. A method of rotating a telegraph pole embedded in the ground about an axis substantially along the length of the pole, the method comprising passing a strap having one end thereof connected to an arm around the pole, trapping the free end of the strap between the pole and the arm held substantially perpendicular to the rotation axis, and rotating the arm about the rotation axis so as to rotate the pole.

14. A device for rotating telegraph poles, substantially as described herein with reference to, or as shown in, the accompanying drawings.

15. A method of rotating telegraph poles, substantially as described herein with reference to, or as shown in, the accompanying drawings.