Road structure – process – or apparatus – Apparatus – Material distribution means
Patent
1996-09-13
1998-07-14
Lisehora, James
Road structure, process, or apparatus
Apparatus
Material distribution means
404119, 404120, E01C 1912, E01C 2306
Patent
active
057793905
DESCRIPTION:
BRIEF SUMMARY
The object of the invention is a device for levelling a layer of sand as a landing place for various jumping events, which device includes rails on either side of the sand layer and a trolley moving backwards and forwards along them and which further includes at least a rake member for loosening the sand layer, a sand-moving member for filling pits, and a levelling member for levelling the loosened sand layer, as well as devices for moving these in a vertical direction.
During a competition the surface of the landing place is depressed after the jumper has left it and as a result of the footprints of the measurers. This happens especially when the sand is damp in rainy weather. Because a jumper strikes the landing place at an angle of about 45.degree., every change in the level of the landing place causes a difference in the length of the jumps. If the depressed surface is raised to the zero level by adding sand, then the jumper who jumps immediately after the raising suffers most from this. This being the case, it is of absolute importance when determining the correct length of a jump that the surface of the landing place is at the same level for each jump for the entire duration of the competition.
One kind of sand layer levelling device is known from German patent application DE 2 448 830, which consists of a rake member and a levelling member. The rake member consists of pins or plate members set in two transverse rows and which extend deep into the sand layer. The rows of this kind are pulled over the sand layer, when the sand layer becomes thoroughly loosened. After these comes a levelling member, formed by a transverse plate, which ploughs the mass over the surface to be levelled forwards, leaving a level surface. A slightly modified sand layer levelling device is known from Finnish patent 76395, which also consists of sand moving and levelling devices attached to a trolley. The moving member consists of a plough-like member, which can be moved laterally at the location of a pit. The levelling member is hinged in such a way that when it moves in the opposite direction it follows the uneven surface of the sand layer and operates only when the trolley is moved in the levelling direction. Both of the aforementioned devices are principally intended for manual operation, even though in the Finnish application reference is made to possible mechanical operation. They are not, however, very suitable for mechanical operation, because the trolley can rise over uneven sand. In any event, the device in accordance with the Finnish patent demands visual estimation of the location of a pit, at which the sand moving member should be set in a lateral direction.
It is the intention of this invention to create an easily mechanized, efficient, and reliable sand layer levelling device. The characteristic features of the invention are presented in the accompanying Patent claims.
According to the invention it is precisely a rake member that is used, even though it demands relatively great power. In mechanical operation this is no drawback, but by means of a rake member efficient loosening and lightening of the sand is achieved, when compaction is minimized during a competition.
In what follows the invention is illustrated with reference to the accompanying Figures, which show one levelling device in accordance with the invention.
FIG. 1 shows the levelling device seen from in front.
FIG. 2 shows the levelling device seen from the rear.
FIG. 3 shows the lifting devices of the rake and moving members seen from the side.
FIGS. 4 and 5 show the arrangement of the support and drive wheels of the trolley.
In FIGS. 1 and 2 the sand layer is marked with reference number 1, the rails with reference number 2, and the trolley itself with reference number 3. The support wheels of the trolley run inside a C-profile rail, so that they are not able to rise, even under the greatest loading. The first moving member 5.1, which is composed of several plough-like members, is in the front of the device and the rake member 4 is behind the devi
REFERENCES:
patent: 2065698 (1936-12-01), Heltzel
patent: 2224084 (1940-12-01), Mills et al.
patent: 5599135 (1997-02-01), Delaurenti
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