MECHANISM FORA TELESCOPIC RIG SYSTEM

TECHNICAL FIELD

The invention generally relates to the construction industry and more particularly to a mechanism for a telescopic rig system including a telescopic support column, a drill column for a concrete drilling machine, the drill column pivotal about a horizontal axis of rotation for positioning the drill column in desired directions, and said mechanism which includes a housing movable along the support column, and an assembly carried by said housing for holding said drill column, said assembly including holding arms projecting horizontally from said housing, said holding arms including an arm unit on each side of the rear end section of the drill column, extending in vertical, parallel planes, a pivot shaft provided with at least one circular-cylindrical surface matching said circular holes in the arm units, and defining said axis of rotation, extending rotary through said circular and coaxial holes in said arm units, and clamping members for locking a rear end section of the drill column between said holding units in any of said desired directions.

BACKGROUND OF THE INVENTION

Drilling machines of the type which are employed for drilling large holes through walls, floors and ceilings made of concrete, are quite heavy. Therefore, when holes shall be established in walls, or when holes shall be made in ceilings or floors at oblique angles, a considerable moment is developed on the drill column due to the heavy machine carried by the drill column. To the static stress on the locking assembly for locking the drill column in desired directions, also shall be added dynamic stresses when the drilling machine is in operation. Especially the problems which are encountered when drilling oblique holes through walls, floors and ceilings are severe and have not been solved satisfactorily according to prior art.

BRIEF DISCLOSURE OF THE INVENTION

It is a purpose of the invention to address the above mentioned problem. For this purpose, the mechanism of the invention is characterised in that the rotary shaft is connected non-rotary to the rear end section of the drill column, and that said clamping members on each outer side of the arm units include clamping members which are connected non-rotary to the pivot shaft and are releasably pressed, in their locking state,

directly or indirectly against the surfaces of the arm units on said outer sides of the arm units, clamping and locking the rear end section between the arm units.

Further objectives, characteristic features and advantages of the invention will be apparent from the dependent claims and from a detailed description of the mechanism according to a preferred embodiment of the invention.

BRIEF DESCRIPTION OF DRAWINGS

In the following detailed description of a preferred embodiment of the invention, reference will be made to the accompanying drawings, in which

Fig. 1 is a perspective view of a telescopic rig system in which the mechanism of the invention is employed.

Fig. 2 is a perspective view showing the mechanism of the invention mounted on a support column and a rear section of a drill column directed vertically downwards, Fig. 3 shows the mechanism viewed in the same direction as in Fig. 2, including a rear member of the drill column locked in a horizontal direction, Fig. 4 is an exploded view of the mechanism of the invention, Fig. 5 shows said rear member of the drill column as viewed in the direction of the horizontal axis of rotation for positioning the drill column in desired directions,

Fig. 6 shows said rear member in a view along the line VI-VI in Fig. 5, Fig. 7 shows the same rear member in cross-section along the line VII-VII in Fig. 6, Fig. 8 is a cross-sectional view of the mechanism of the invention in a vertical plane defined by said axis of rotation, including said rear member of the drill column shown in Fig. 3 but positioned vertically as in Fig. 2 and viewed in the direction of arrows A indicated in Fig. 2 and in Fig. 3, and Fig. 9-11 illustrate, more schematically, the working principles of the preferred embodiment of the mechanism of invention described with reference to the foregoing drawings, a mechanism employing some of the features of the invention and a prior art mechanism, respectively.

DETAILED DESCRIPTION OF THE INVENTION With reference first to Fig. 1, a telescopic rig system for attaching and operating concrete drilling machines is generally designated 1. It includes a telescopic support column 2 including a lower, first section 3 and an upper, expandable section 4, which can be moved out from and into the first section 3. A drilling machine, which is not

shown in the drawing, can be attached to a quick-action attachment device 12 on the drill column 5 in a manner per se. The lower end of the first section 3 of the telescopic support column 2 and of the drill column 5 are detachably secured to a base structure 6. Before operation of the not shown drilling machine, the lower end of the drill column 5 is released from its engagement with the base structure 6, allowing the drill column 5 and the drilling machine attached to the drilling column 5 to be directed against a floor, a wall or against the ceiling. The attachment device 12 carrying the drilling machine can be moved along the column 5 by means of a handle 14, operating a gear and rack unit.

The drill column 5 consists of a tube 8 with a front end which can be attached to the base structure 6 when the drilling machine is not in operation, and a rear member 13, which forms part of mechanism 10. The tube 8, which is provided with a rack 11 included in the mentioned gear and rack unit, can be releasably attached to said rear member 13 such that the integrated drill column 5 is established as shown in Fig. 1. Thus, in the integrated drill column 5, said rear member 13 forms part of the drill column and is coaxial with the tube 8.

A safe operation of the drilling machine not only requires that the rig system 1 is very stable, which can be achieved therein at the expandable column support 2 is clamped very firmly between the floor and the ceiling via a ceiling plate 7, but also that the drill column 5 can be locked safely in any chosen drilling direction. For that reason, the mechanism 10 is designed according to the invention as will be described in the following with reference to Figs. 2-9.

The mechanism 10, Fig. 3, includes a housing 15 and, in the housing 15, and projecting upwards there from, a sleeve 16, which is mounted on the lower section 3 of the telescopic support column 2, Fig. 2. The housing 15 and the sleeve 16 are designed in a manner known per se and can be moved along the said section 3 by means of a motion assembly including a not shown gear in a gear casing 17 in cooperation with a rack 18 on said lower section 3 of the support column 2. A detachable handle 19, Fig. 2, is provided for cranking the mechanism 10 up and down along the column 2. The mechanism 10 can be locked in desired positions by means of locking screws which can be turned by means of handles 20, 21 in a manner known per se.

In the exploded view in Fig. 4 some complementary details on the housing 15 have been deleted. Other components of the mechanism 10 now shall be described with reference to Fig. 4 and Fig. 8.

Two holding arm units 23, 24, which are secured by welding to the housing 15 extend horizontally from the housing. Each arm unit 23, 24 consists of two vertical, parallel discs, referred to as inner 23a, 24a and outer 23b, 24b discs, respectively, a gap 25 and a gap 26 being provided between the inner and outer discs 23a and 23b and between the inner and outer discs 24b and 24b, respectively. Front sections 27 and 28 of the two arm units 23 and 24 respectively, are parallel with one another. Rear sections 29, 30 of each arm unit are bent at a slight angle, widening the gap between the arm units 23 and 24 adjacent to the housing 15, as is shown in the drawings. Circular through holes 31 and 32 are provided in the discs 23a, 23b and 24a and 24b, respectively, in the region of the parallel front sections 27 and 28 of the two arm units 23, 24.

The rear member 13 of the drill column 5 includes a rear end section 35 and, in the opposite end, an attachment section 34 including a male coupling member 36. A female coupling member 37 is secured to the rear end of the tube 8. In combination, the male and female coupling members 36, 37 and a lock screw 74, Fig. 2, allow a safe attachment of the tube 8 to the mechanism 10. The tube 8 - and hence the not shown drilling machine mounted on the attachment device 12 - can be turned about the longitudinal central axis of the drill column 5 and be locked in four different positions by means of a locking screw 38 provided in an intermediate section 39 between the rear end section 35 and the coupling members 36, 37. A screw hole is designated 40.

Reference now shall be made also to Fig. 5, Fig. 6 and Fig. 7, which illustrate the rear member 13 and its rear end section 35 more in detail, including also the interior thereof. Basically, the main part of the rear end section 35 consists of a rectangular piece of tube 42 having two first, parallel tube surfaces 43a, 43b and two second flat, opposite and parallel side surfaces 44a, 44b forming right angles to the planes of said first tube surfaces. A first, flat washer 45a is secured through welding to said first tube surface 43a and a second, flat washer 45b is correspondingly secured to the opposite tube surface 43b. Circular, coaxial holes 46 are provided in said first and second washers, one in each washer. The holes 46 are of same size as the holes 31 and 32 which are provided in the arm units 23 and 24. The outer surfaces of said first and second washers 45a and 45b form first and second side surfaces 47a and 47b, respectively of the rear end section 35. Said first and second side surfaces 47a and 47b are parallel, flat and vertical in the mechanism 10, as viewed in Fig. 4 - Fig. 7. Circular, coaxial holes 48 of same size as the holes 31, 32 and 46 are also provided in the side walls of the rear end section 35 against which the first and second washers 45a and 45b are secured. The said first and second washers 45a and 45b have two objectives. One objective is to provide the annular surfaces 47a and 47b which shall act against the inner surfaces of the

portions of the inner discs 23a and 23b, which surround the holes 31 and 32, contributing to the lock function of the mechanism 10. Another objective is to distribute the clamping force which shall be exerted in the assembly, so that the first tube walls 43 of the rectangular piece of tube 42 shall not be damaged.

Inside the rectangular piece of tube 42 there is provided a body 50 between the two opposite side walls, against the interior surfaces of which the tubular body 50 is secured through welding. According to the embodiment, the tubular body 50 has an outer circular contour with a larger diameter than the circular holes 46, 48. The passage-way 51 through the body 50 has a square cross-section and is coaxial with the circular holes 46, 48. As is seen in Fig. 5, the contour of the passage-way 51 can entirely be contained within the area of the circular holes 46 and 48.

A levell 52 is accommodated in a recess 53 in each of said second tube walls 44. In the assembled mechanism 10, the rectangular end section 35 of the drill column is covered by a plastic lid 54.

Aligned with said first and second washers 45a and 45b, and the tube passage-way 51 of the tubular body 50, the assembled mechanism 10 includes three further washers, namely a third washer 56 accommodated in the gap 25, a fourth washer 57 accommodated in the gap 26 and a fifth washer 58 provided outside of outer disc 24b. Said third, fourth and fifth washers 56, 57 and 58 have equal square holes 56a, 57a, 58a with a size corresponding to the square section of the square passage-way 51 through the tubular body 50 inside the rectangular end section 35. All the said circular and rectangular holes are coaxial.

A pivot shaft 60 and a nut 61 serve as force developing members. The pivot shaft 60 for that purpose has a thread 62 in one end, cooperating with the nut 61 and a wide screw head 63 in the opposite end with a diameter which is equal with the diameter of the said washers 45a, 45b, 56, 57, 58.

The pivot shaft 57a has four flat surfaces 65 matching the sides of the square holes 56a, 57a, 58a of the third, fourth and fifth washers 56, 57 and 58 and the square section of the passage-way 51 of the tubular body 50 in the end section 35. Further, the pivot shaft 57a has four circular-cylindrical surfaces 66 between the flat surfaces 65, matching the circular holes 31 and 32 in the first and second holding arm units 23 and 24 as well as the circular holes 46 and 48. This allows the pivot shaft 57a to rotate about its axis of rotation 59 and be journalled in the circular holes 31 and 32 in the discs of the holding

arm units, when the clamping force is released by easing the nut 58a, but prevents it from rotating in the square holes 56a, 57a, 58a of the third, fourth and fifth washers 56, 57, 58 and also prevents it from rotating in the end section 35 because of the square section of the passage-way 51 in the tubular body 50.

As is shown most clear in Fig. 8, the discs and washers form a compact pack in their clamped, locking condition between the clamping members 63 and 58, when the nut 61 is tightened against the clamping member/fifth washer 58. In this pack, the outer disc 23b of the first holding arm unit 23 is clamped between said third washer 56 and the combined screw and pivot shaft head 63. The third washer 56 is clamped between the inner and outer discs 23a and 23b of the first holding arm unit 23. The inner disc 23a is clamped between the third washer 56 and the first washer 45a, whereas the fourth washer 57 is clamped between the inner disc 24a and outer disc 24b of the second holding arm unit 24.

Further in the pack, the rear end section 35 is clamped with its first and second washers 45 a and 45b between the inner surface of the inner disc 23 a of the first arm unit 23 and the inner surface of the inner disc 24a of the second arm unit 24, the tubular body 50 serving as a reinforcement of the rectangular end section 35, supporting the walls 43. The inner disc 24a of said second holding arm unit 24 is clamped between the second washer 45b and the fourth washer 57, which in turn is clamped between said inner disk 24 and said outer disc 24, whereas the outer disc 24b of the second holding arm unit 24 is clamped between the fourth washer 57 and the fifth washer 58. In other words, there are a great number of surfaces which are pressed against one and another.

As a matter of fact, surfaces of discs and washers (also the pivot shaft head in this case serves like a washer) are clamped against one and another in eight different friction planes which are symbolically indicated as arrows in Fig. 9. As a comparison, in a conventional locking mechanism shown in Fig.ll, only two friction planes are present. The concept of friction plane in this context means a plane in which relative movement between two contacting surfaces may occur, if the friction force is overcome. In the mechanism of the invention, a moment acting on the drill column 5 is transferred as a torsion force acting on the pivot shaft via the tubular body 50 which is non-rotary mounted on the pivot shaft 60. The torsion force is transferred by the pivot shaft to the washers 56, 57 and 58, which likewise are non-rotary mounted on the pivot shaft and also to the pivot head 63 which forms an integrated part of the pivot.

Assuming that the clamping force generating members, i.e. the pivot shaft 60 in its roll as a screw and the nut 62, generate an axial clamping force F , the objects which are pressed against one another in the said friction planes are pressed against one another with the same force F in all the friction planes. The friction forces which are developed in the eight friction planes of the embodiment of the invention, Fig. 9, therefore are added to one another. Assuming further that the friction coefficient is equal in all the eight friction planes of the embodiment of the invention shown in Fig. 9 as well as in the two friction planes of the prior art mechanism shown in Fig. 11, the mechanism of the invention generates four times as large total friction force than the prior art mechanism. The embodiment shown in Fig. 10 employs only two discs, as according to prior art, but creates nevertheless four friction planes and is therefore twice as effective as a locking device than the prior art mechanism of Fig. 11. It is in principle also possible to design a mechanism of the invention in which the number of discs are not equal on both sides of the rear end section 35 of the drill column but a correlated number of washers are employed according to the principles of the invention as described above.

In order further to increase the clamping force, and hence the friction forces, the thread 62 of the pivot shaft 57a and the corresponding thread of the nut 58a are designed with an unconventionally small pitch. It is also possible to employ other clamping force generating devices than a screw and nut coupling, e.g. a bolt and wedge coupling, in which the bolt may have a head in one end and a longitudinal through slot in the other end, fitting a flat wedge..

The mechanism 10 also includes an additional lock device of a conventional type, which is useful when the drill column 5 is raised to a horizontal position, Fig. 4. That lock device includes two lock levers 69 and 70 secured on a shaft 71, which extends through two circular holes 72 in the second tube walls 44 of the rear end section 35. In the horizontal position of the drill column 5, the shaft 71 can be rotated in the holes 72 by means of a handle 73, causing the lock levers 69 and 70 to be turned 90° as shown in Fig. 3. In this position, the lock levers 69 and 70 are pressed against the upper and lower edges of the vertical discs 23a, 23b and 24a, 24b, at the same time as the lock levers 69 and 70 also are pressed against the flat second side surfaces 44a and 44b of said rear end section 35, locking the drill column 5 in its horizontal position. Even in this case, however, the locking based on friction between a great number of surfaces, including the discs, washers and screw and nut coupling plays a roll because, if the conventional lock device 68 would fail, e.g. because the shaft 71 would be turned unintentionally by means of the handle 73, the heavy drilling machine would not drop down but be

maintained in its position, such that the extra locking by means of the lock device 68 can be reestablished.

It should be understood that the mechanism 10 of the invention can be modified within the frame of the invention. For example, the number of discs in each of the holding arm units may be more than two and the number of washers provided with square holes between the discs be correspondingly increased in order further to increase the friction surfaces of the assembly. The discs 23a, 23b, 24a, 24b are suitably made of steel, which affords them some flexibility in the horizontal direction, which is desired and important because it makes it possible to clamp the discs and washers together efficiently, even if the accuracy of manufacture is not perfect. Also the various washers, which have been described in the foregoing, are conveniently made of steel, but other materials can be contemplated as well, particularly materials with a higher friction coefficient as well as using washers and/or discs which are covered with a high friction material. According to the embodiment, the gaps 25 and 26 between the inner and outer discs extend all the way from the housing along the rear and front sections 27-30 of the holding arm units 23, 24, which is convenient. However one might conceive to restrict the extension of the gaps 25, 26 to only the front sections 27, 28, which would make the rear sections 29, 30 stronger but afford the front sections 27, 28a sufficient flexibility in the horizontal direction. It is also possible to design that portion of the rear end section 35 of the drill column which forms a central part of the pack of clamped members as a solid, flat bar, with a through hole with square cross section.