A vibrating hammer, more particularly for driving sheet piles into the ground

Abstract: The invention relates to a vibrating hammer (1), more particulary for driving sheet piles into the ground, said hammer having a lower side with a number of parallel horizontal guide tracks (3), slide blocks (4) being mounted for adjustment said tracks (3), said blocks (4) having each a pair of clamping jaws (5) adapted to grip a sheet pile, the clamping faces of said clamping jaws (5) extending at right angles to the longitudinal direction of the guide tracks (3). According to the invention, the pairs of clamping jaws (5) take such a position on the sliding blocks (4) engaging said guide tracks that the centre lines (C) of the clamping jaws lie laterally offset relative to the longitudinal axis of the respective sliding blocks (4).

Description: The invention relates to a vibrating hammer as defined in the first part of claim 1. Such vibrating hammers are known from FR-A-2527667 and DE-A-1634426 and are used to vibrate a plurality of sheet piles (e.g. two sheet piles in the case of two guide tracks), into the ground simultaneously. In such a case the two piles to be vibrated into the ground simultaneously are beforehand - generally at the factory - coupled to one another by sliding their adjacent longitudinal edges into mutual engagement. The pair of sheet piles thus coupled has, when viewed from above in the vertical position, a (modified) sine profile that extends through one wavelength. This profile must be clamped between the cooperating clamping jaws of the two pairs of clamping jaws at the position of the "crests" (= the centre of the "short parallel sides" of the essentially trapezium-shaped sheet piles). To this end, the vibrating hammer - suspended from a load carrying hook - is placed in such a position above the vertically positioned pair of sheet piles, that the two guide tracks will become directed at right angles to the "wave direction" of the sine profile. Beforehand the blocks are fixed on or in the guide tracks in such a position that the spacing between the two pairs of clamping jaws, as measured in the longitudinal direction of said guide tracks, corresponds to twice the amplitude of the sine profile (= the distance measured crosswise between the "shorter parallel sides" of the two trapezium-shaped sheet piles). In this way the vibrating hammer can be adapted to sheet piles having different profile heights. Sheet piles, however, may vary in width as well as in profile height (amplitude). Common profile widths are 400, 500 and 600 mm. This means that the spacing measured in the "wave direction" between the two pairs of clamping jaws, and thus the spacing between the two guide tracks, must be changed in dependence on the width of the sheet piles to be driven into the ground. To this end it has been the practice to adjust the guide tracks, which are contstituted by relatively heavy rails, in the transverse direction. This, however, is a difficult and time-consuming procedure. For, on account of the heavy vibrations to which the fastening of the rails to the lower side of the vibrating hammer is subjected during operation, the rails have to be fixed with many heavy bolts, all of which have to be removed and subsequently refitted and tightened, while using different holes in the body of the vibrating hammer. It is an object of the invention to overcome this drawback of the well-known vibrating hammer. According to the invention, this aim is achieved by the features mentioned in the second part of claim 1. As compared with the well-known vibrating hammer, with which the longitudinal axis of each guide track is in the same vertical plane as the common centre line of the cooperating pair of clamping jaws on the respective slide block, the invention enables the spacing between the centre lines of the two cooperating clamping jaws of the two pairs of clamping jaws to be changed by simply reversing a sliding block or both of the sliding blocks in (on) the guide tracks (rails) and thereby causing the centre lines of the cooperating clamping jaws to become lying offset towards the opposite side of the longitudinal axis of the respective guide track(s). This avoids the need for the guide tracks to be removed and refitted. The sliding blocks carrying the pairs of cooperating clamping jaws are simply slid off the respective guide tracks (rails), turned back to front and then repositioned. In a practical example of a vibrating hammer with two guide tracks which are 500 mm spaced apart, lateral offsetting of the two pairs of clamping jaws relative to the longitudional axes of the guide track through an extent of 50 mm leads to the following three sheet pile widths: 500 - 50 - 50 = 400 mm 500 + 50 - 50 = 500 mm and 500 + 50 + 50 = 600 mm The invention also relates to a particular accessory for use with such a vibrating hammer, which accessory is defined in the first part of claim 2. It is well-known per se to use such an accessory with a vibrating hammer of the type disclosed in FR-A-2 527 667 or DE-A-1634426, when it is desired to use the vibrating hammer for driving a pipe into the ground. In that case the two pairs of clamping jaws must engage the upper edges of the pipe at diametrically opposite locations, which requires mutual aligned positions of the two pairs of clamping jaws and with the common center lines of the cooperating clamping jaw faces lying in the vertical plane through the centre of gravity of the hammer. Accordingly, mounting the auxiliary slide block and placing the two clamping jaws carrying slide block in sliding engagement with the auxiliary guide track brings the well-known vibrating hammer in a condition for driving pipes instead of sheet piles into the ground. In order that the vibrating hammer of the present invention may be used for driving pipes into the ground as well, the accessory to be used in cooperation with the hammer according to claim 1 distinguishes from the well-known accessory by the features which are defined in the second part of claim 2. The invention will be hereinafter explained in greater detail with reference to an exemplary embodiment shown in the drawing, wherein: Fig. 1 shows a front view of a vibrating hammer with two pairs of clamping jaws according to the invention; Fig. 2 is a side view of the vibrating hammer according to Fig. 1; Figs. 3A, 3B and 3C show diagrammatic plan views of three vertically positioned pairs of sheet piles of different widths, wherein the rails of the same vibrating hammer are indicated by dash-dotted lines, while also showing the positions of the pairs of clamping jaws, adapted to the width of the pairs of sheet piles and gripping the upper edge of the respective pairs of sheet piles and Fig. 4 shows a side view of the bottom part of the vibrating hammer, with which an asseccory in the form of an auxiliary slide block is placed in sliding engagement with both of the guide tracks and is provided with an auxiliary guide track to receive both of the clamping jaws carrying slide blocks. The vibrating hammer shown in the drawing is of a type which is known per se, and comprises a housing of a heavy design, within which vibrating elements (not shown), are mounted for rotation about axes p, q, r and s by a driving motor (neither shown). Reference number 10 indicates a vibration-damping device, by means of which the housing 1 can be dampingly suspended from the load hook of a crane. The housing 1 has at its lower side a heavy platen 2, provided with two parallel guide tracks in the form of rails 3 which are fastened thereon by means of bolts (not shown). The (vertical) planes of symmetry of the rails 3 are indicated at 'a' in Fig. 2, while the plane of the center of gravity of the vibrating hammer, parallel thereto and lying midway between them, is indicated at 'b'. A sliding block 4 is provided on each rail in such a way that it can be slidably adjusted and fixed. Said sliding block is integrally formed with a clamping device 5, that has a fixed clamping jaw 5a and a movable (e.g. hydraulically operable) clamping jaw 5b. The common centre lines through the centres of the cooperating clamping faces of each pair of clamping jaws 5a, 5b are indicated at 'c'. As can be seen in Fig. 2, the clamping devices 5 with the respective pairs of clamping jaws 5a, 5b have their centre lines 'c' laterally offset through an extent 'x' relative to the planes of symmetry 'a' of the guide tracks (rails) 3. In the situation shown in Fig. 2 both pairs of clamping jaws 5a, 5b are in a laterally outwardly directed offset position, wherein the spacing between the two pairs of clamping jaws is A + 2x, when A is the spacing between the rails 3. As may be easily understood, an interchanging of the two clamping devices 5 will result in a situation in which the pairs of clamping jaws will become positioned offset inwardly, due to which the spacing between the two pairs of clamping jaws will be A - 2x. There is yet a third possibility, which arises when in the situation shown in Fig. 2 one of the sliding blocks 4 of the corresponding rail 3 is slid off and, after being turned back to front, is repositioned onto the respective rail 3. In this situation one pair of clamping jaws is in an outwardly directed offset position, whereas the other pair of clamping jaws is taking an inwardly directed offset position. In this case the spacing between the two pairs of clamping jaws will be A - x + x = A. The three possibilities indicated above are shown diagrammatically in Figs. 3A, 3B and 3C. In this case pairs of sheet piles are involved, the (single) pile widths of which are A + 2x; A - 2x and A respectively. To drive said pairs of sheet piles into the ground use is made of a vibrating hammer, the rails of which have a fixed spacing A, while the pairs of clamping jaws 5a, 5b mounted thereon are lying offset to an extent 'x'. The distance H (= twice the profile height of a single sheet pile) has been selected the same for all three cases and corresponds to the distance H between the guide tracks (rails) in Fig. 1, which in practice can generally vary between 700 and 1700 mm. In Fig. 4, in which the bottom part of the vibrating hammer according to Figs. 1 and 2 is shown, an accessory in the form of an auxiliary slide block 11, provided with complementary grooves, is slid onto both rails 3. The auxiliary slide block 11 may extend over the full length of the rails 3 and carries at its lower side an auxiliary rail 12, having a symmetrical cross-sectional profile that corresponds to that of the rails 3. The auxiliary rail 12 serves to receive both of the slide blocks 4 in such a position that the two pairs of clamping jaws (5a/5b) are in alignment with one another. Furthermore, in accordance with the invention, the vertical plane of symmetry a' of the auxiliary rail 12 is positioned laterally offset relative to the vertical plane b to an extent that may compensate for the lateral offset position of the pairs of clamping jaws 5a, 5b relative to the phase a'. This allows the slide blocks 4 with the two pairs of clamping jaw to be mounted such that the common centre lines c of the cooperating clamping faces of both pairs of clamping jaws 5a, 5b fall within the vertical plane b through the center of gravity of the hammer. In the position shown in fig. 4, the pairs of clamping jaws (5a, b) may engage a pipe at two diametrically opposite positions so that the resultant driving force exerted by the hammer will go through the centre of the pipe.

Claims: A vibrating hammer, especially for driving sheet piles into the ground, said hammer having a lower side with a pair of guide tracks (3) provided thereon and extending horizontally and parallel to one another, a slide block (4) being removably placed in sliding engagement with each of said guide tracks (3) and mounted for adjustment along the respective guide track (3), each of the slide blocks (4) carrying a pair of clamping jaws (5a, 5b) with cooperating clamping faces that are positioned at right angles to the longitudinal direction of said guide tracks (3) and are mounted for movement relative to one another longitudinally of said guide tracks (3) so as to clamp a sheet pile therebetween, characterized in that the common centre line (c) of the cooperating clamping faces of each pair of clamping jaws (5a, 5b) is positioned laterally offset relative to the vertical plane of symmetry (a) of the respective guide track (3), such that an act of slidingly removing a slide block (4) from the respective guide track (3), turning said slide block (4) back to front and remounting the slide block (4) on said guide track (3) brings said slide block (4) in a position, in which the common centre line (c) of the cooperating clamping faces of the respective pair of clamping jaws (5a, 5b) is laterally offset relative to said plane of symmetry (a) in an opposite direction. An accessory for use with a vibrating hammer according to claim 1, with which said guide tracks (3) are positioned symmetrically relative to a vertical plane through the centre of gravity (b) of the hammer, said accessory comprising an auxiliary slide block (11) adapted to be placed - when said clamping jaws carrying slide blocks have been removed - in sliding engagement with both of said guide tracks (3) of said hammer, said auxiliary slide block having at its lower side an auxiliary guide track (12) adapted to slidingly receive both of said clamping jaws carrying slide blocks (4) of said hammer, with the common centre line of the cooperating clamping faces of the two pairs of clmaping jaws (5a, 5b) coinciding with one another, said auxiliary guide track (12) having its vertical plane of symmetry - when the auxiliary slide block is mounted in place - positioned parallel to and between the vertical planes of symmetry of the guide tracks (3) on the lower face of the hammer, characterized in that said auxiliary guide track (12) has its vertical plane of symmetry positioned laterally offset relative to said vertical plane through the centre of gravity (b) to an extent which corresponds to the extent (x) of the lateral offset of the common centreline of the cooperating clamping faces of the pair of jaws (5a, 5b) relative to the vertical plane of symmetry (a) of the respective guide track (3).

Inventors: VAN HALTEREN TIJMEN, VAN HALTEREN, TIJMEN
Applicants: HALTEREN TIJMEN VAN, VAN HALTEREN, TIJMEN
Application year: 1995
Main classification: E02D7
IPC codes: E02D13, E02D7