Conveyors: power-driven – Conveyor section – Endless conveyor
Reexamination Certificate
1998-10-23
2001-06-05
Olszewski, Robert P. (Department: 2167)
Conveyors: power-driven
Conveyor section
Endless conveyor
C198S853000, C474S219000
Reexamination Certificate
active
06241080
ABSTRACT:
The invention relates to a method for chain drive, whereby the chain, such as a transmission chain, conveyor chain and/or like, is formed of several shaped pieces, that are connected to each other one after another at jointing points by means of joint pins. The chain is being driven by means of a wheel arrangement, that includes at least one chain wheel, such as a drive wheel, a turning wheel or a like.
The method according to the invention may be exploited even with a so called traditional chain structure, in which the power transmission of the chain structure is being transmitted by a drive wheel, the tooth shape of which is usually standardized. The meaning of the invention is of importance in more developed chain structures, also, in which e.g. the supporting surface of the chain comprises notches, that are crosswise in respect to the moving direction of the chain and that are during conveying of the chain in cooperation with counterpart surfaces, such as drive pins or like belonging to the chain wheel, that are arranged according to the notches and essentially crosswise in respect to the moving direction.
The type of developed chain structure described above is previously known e.g. from Finnish Patents FI 64707 or FI 91798. The shaped piece being represented in these comprises a notch existing crosswise in respect to the moving direction of the chain, the length of which corresponds to the width of the shaped piece, and which is advantageously placed near the other link point of the shaped piece. In this case when the chain bends on the drive wheel an advantageous lever arm is achieved, thanks to which the chain force influencing the chain structure presses the notches of the chain harder against the pins of the drive wheel. This solution decreases significantly a so called skipping of the chain. In addition to that due to the lever arms being achieved the chain structure disengages easily from the chain wheel on the releasing side, whereby a so called non-disengagement of the same is prevented.
The chain structure according to Patent FI 64707 has proved to be significantly better than corresponding earlier solutions, particularly thanks to the lever arms being achieved. In certain purposes, such as in chain structures being used in water refineries, plastics or corresponding non-metallic materials have been exploited because of corrosion and to decrease the specific gravity of the chain. In this case in certain applications there has been found problems, that are caused by bending forces directed to the chain in the level corresponding the joint pins e.g. because of natural bending of the chain when the chain is being used in such position, that the joint pins are in a vertical position. Due to this during cooperation between ordinary straight joint pins and corresponding straight counterpart surfaces existing in the shaped piece even a small angular alteration causes always that, that the counterpart surfaces of successive shaped pieces are in contact with each other only by the other edge of the same. This naturally causes wearing of both the joint pins and counterpart surfaces, because the surface pressures are very high e.g. when the chain starts to move in such a bended situation as described above.
The above is valid with the solution according to Patent FI 91798, also. The purpose of this solution is mainly to improve functioning of the chain particularly with a view to skipping and non-disengagement of the same, in which respect with the solution in question there has been achieved remarkable improvement when compared to traditional solutions particularly in certain types of purposes. In the solution according to FI 91798 the free longitudinal internal measure of the notches of the chain is arranged to change, in which case, when the notches formed by the shaped pieces of the chain are in cooperation with the counterpart surfaces of the drive wheel, the free longitudinal internal measure of each notch may be altered to correspond the contact length of the corresponding counterpart surface, that is the diameter of the drive pin. With this solution the typical problems involved with solutions known previously, such as skipping and non-disengagement of the chain may be avoided. In addition to that a chain of this type may be used with as high loads to both moving directions, that has not been possible earlier with corresponding solutions.
Thus, when manufacturing chains nowadays for most heterogeneous purposes particularly of non-metallic materials, the bending stress directed as described above has been found to be a very big problem in practical. Because of this the chain starts to behave undesirably, sometimes even after a very short use, correcting of which requires changing the chain. In practice this always causes disproportionately long interruptions of use and organizing problems both in storing and maintenance. In certain uses the bend stress as described above may be so powerful, that continuous observing as well as maintenance measures are required with very short intervals e.g. to tighten the chain for removing of the clearances caused by wearing.
It is the aim of the method for according to this invention to achieve a decisive improvement in the problems presented above and thus to raise substantially the level of knowledge in the field. To achieve this aim, the method according to the invention is primarily characterized in, that, particularly wearing of the chain, that is due to bending of the chain essentially along the longitudinal direction of the joint pins, is being minimized by taking advantage of joint pins, the cross section of which changes in the longitudinal direction.
As the most important advantages of the method according to the invention may be mentioned the simplicity of the same as well as the simplicity of the practical structures of the same as well as of the mounting measures relating to the same. As described above, when exploiting advantageously e.g. joint pins, that are continuously conical, the surface pressures may be optimized under all circumstances in a way, that the type of bending of the chain may be even totally eliminated in principle. In addition to that by exploiting the type of joint pins even mounting of the chain may be eased by the guiding influence of the conical joint pin.
Advantageous embodiments of the method according to the invention are presented in the dependent claims directed to the method.
The invention relates to a chain functioning according to the method, also, that is represented in greater detail in the preamble of the independent claim related to the same. The primary characteristics of the chain are represented in the characterizing part of the corresponding claim.
As the most important advantages of the chain according to the invention may be mentioned simplicity and reliability of the same, whereby with the same it is possible to increase significantly the operating time of the chain. This is thanks to that, that the surface pressures being caused by bending of the chain along the longitudinal direction of the joint pin may be minimized in a surprising and extremely advantageous way differing from the traditional solutions, by exploiting e.g. continuously conical joint pins. In this case during the bending situation of the above type of the chain the joint pin and the corresponding counter part surface in the shaped piece tend to settle within each jointing point to a most advantageous position in respect to the mutual surface pressures. This is why high point surface pressures are avoided that are always caused to joint pins and corners of the counterpart surfaces of the shaped pieces of conventional right-angled solutions. One crucial advantage of the chain according to the invention is furthermore that, that the chain may be mounted easily by influence of the guiding effect of the e.g. conical joint pins.
Advantageous embodiments of the chain according to the invention are represented in the dependent claims related to the chain.
In the following description, the invention is illustrated i
Connolly Bove & Lodge & Hutz LLP
Finnketju Invest Oy
Jaketic Bryan
Olszewski Robert P.
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