Protective cover device

Abstract: Cover device to provide an opening above a cellar which opening can be displaced. The cover device comprises a belt being rigid in transverse direction.

Description: The subject invention relates to a cover device according to the preamble of claim 1. Such a cover device is known from US-A-3,475,064. The belt structure according to that specification comprises a flexible belt at its lower sides provided with reinforcing bars such that this belt structure is rigid in respect of transverse direction. Such a device has several drawbacks. First of all it is very complicated to guide the edges of the belt near the opening because of the presence of the reinforcing bars at the lower side of the belt. Furthermore a considerable impact on the belt will result in permanent distortion of the reinforcing bars and make the belt useless. From DE-A-3,533,767 a cover device is known wherein to an elastic sheet rigid slats are connected. Such a cover device can e.g. be used above pits or cellars in which machines can move to and fro, such as transporting devices, at rolling equipment. Such devices convey material to be rolled from one station to another. To protect such machines as much as possible these are mounted in a cellar and its transport surface being substantially flush with the floor of the rolling device moves to and fro between the stations. To prevent that the space not occupied by the transport surface remains uncovered and a substantial danger arising for operators, as well as giving rise to the introduction of undesired materials into the cellar, a cover device is used. The device according to DE-C-942,431 is complicated, noisy and the guiding devices require considerable maintenance. Also such a cover will be subjected to considerable wear. In the device of DE-C-942,431 dirt will accumulate between adjacent slats. It has been found that if the length of such cover device does exceed 130 m vibrations can be generated during use. The invention aims to obviate these drawbacks. According to the invention this is realized with the characterizing features of claim 1. Such a belt is generally known in the art and explicitly reference is made to EP-A-0 273 478 of applicant. According to this specification such a belt comprises a flexible polymer carrier body in which are disposed two layers which are rigid in respect of deflection in the transverse direction as well as at least one other layer providing longitudinal strength, wherein one of the layers imparting transverse rigidity is combined with the layer imparting longitudinal strength to form one layer consisting of longitudinal and transverse wires, while at least the transverse wires are made of high-modulus material. Of course also other polymer belts being rigid in transverse direction can be used for the subject invention. Such belts being rigid in transverse direction were up to now only used as conveyor belt, more particular for rolling side walks etc. being applied in airports etc. Surprisingly it has been found that such a belt can advantageously be used for covering of the opening moving to and fro. The rigid nature in transverse direction was of importance for the known applications to prevent that a person being on the belt would sense "waving" feeling at passing of the rollers extending over the total width of the belt. Because of using of a belt being rigid in transverse direction only rollers having a limited width at the sides of the belts are necessary. In the subject application the use of rollers having a limited width at the sides is of importance because so space can be provided for a device moving through the opening, such as the conveyor devices at rolling arrangements as described above. The cover device described above provides, in the opening, a displaceable device and this device is bounded at both sides by the belt as described above. Therefore the opening is always covered. Furthermore said belt can be connected such that the opening, in which the device described above is placed can be maintained substantially constant. It is also possible to embody the belt having its two upper sides limiting an opening of variable size. So a device being below the upper surface of the opening can be completely vanished from sight by moving the two subsequent upper side parts towards each other. During the use of the device both upper parts are being moved from each other so that the device being within the cellar can be elevated. According to a further preferred embodiment the belt comprises oil proof material. This is of importance because the device being within the opening often operates with oil, which can contact the belt by leaking. The guiding rollers for the belt being rigid in transverse direction are according to a further preferred embodiment provided near the side walls of the opening to be covered. Because of that a device being inside the opening can move unrestricted to and fro. The belt comprises two upper sides and a lower side connecting these upper sides wherein the lower side is guided over rollers extending across the belt. These rollers extending across the full width of the belt are provided on a location where they do not interrupt the functioning of the device being inside of the opening. To have them extend across the full width a certain controlling effect of the belt is provided. The invention will be further elucidated with reference to a further embodiment shown in the drawing, where: Figure 1 shows schematically and in side elevation a cellar having a cover device according to the invention, and figure 2 schematically in frontal view the device according to figure 1. In figure 1 a pit or a cellar is indicated with 1. In this cellar a schematically shown device 2 moves to ad fro and runs over rails 3. Supply of the device 2 is provided through flexible cables 4, being fixed at 5 at the bottom 6 of the cellar 1. Device 1 has a supporting face 7, to convey a load, e.g. from a rolling device 8 to schematically shown rollers 9. Cellar 1 is provided with an opening 10, in which the support surface moves to and fro. To prevent that a portion of the opening remains uncovered, i.e. is not covered by support face 7, giving a danger for operators, and to furthermore to prevent that non desired material can be introduced, a belt generally referred to with 11, is provided. This belt provides upper sides 12 and 13 and lower side 14 connecting these sides. Upper sides 12, 13 are connected to the support face 7. During moving to and fro of the device belt 11, will move along such that the opening is continuously covered. The belt indicated with 11 is a belt being rigid in transverse direction, having at suspending near its extremities during loading in the middle only a small deflection, This is realised by the presence of layers giving transverse rigidly being spaced as much as possible in said belt. Because of that it is possible to only support the belt near its side extremities with rollers 15 as shown in figure 2. If a load is positioned in the middle of the belt it will not sag. To control the position of the belt in the lower part of the cellar rollers 16 are provided, which extend across the full width of the belt. The belt being rigid in transverse direction being used here has a surface profile being different from the usual ribbed profile of belts being rigid in transverse direction as used in conveyor belt applications. The belt comprises an oil proof polymer material, because for controlling of device 2 hydraulic oil is used which can leak on the belt. Instead of or additionally it is possible to provide a sheet above the lower side of the belt protecting this lower side against leaking of oil. Because of the flexible nature of the belt (generally reinforced rubber material) in contrast to the pallet-chain systems according to the prior art it is prevented that if large loadings for which the belt is not designed are placed on the belt deformation occurs which will remain. Because of that it is not often necessary to stop the device for maintenance. This in contrast to the structure according to the prior art indicated above the belts can have indefinite length because no problems with regard to noise and vibration will occur. A comparative test showed that device according to the prior art when used in a rolling mill had to be overhauled at least each year. The belt according to the subject invention is at least five years free of substantial maintenance. This will mean a considerable increase in service time of the associated device. Furthermore the belt together with its auxiliary driving structure is about 20% cheaper than conventional devices. Although in the above an embodiment of the invention is described being preferred at the time being it has to be understood that many modifications can be introduced without leaving the range of the invention. E.g. it is possible to vary the size of the opening between zero and the width of the supporting face 7.

Claims: Cover device for providing a displaceable protective cover above an opening (10), such as a pit, comprising an apparatus (2) which can move to and fro, a belt structure (11) being rigid in respect of deflection in transverse direction and comprising at least one flexible belt of which a free extremity is connected to the apparatus and wherein near the side walls of the opening to be covered, guiding means (15) are provided for the belt leaving the opening substantially clear, characterized in that , said belt structure comprises only one flexible belt, being a polymer belt having flat outer faces and internal layers being rigid in transverse direction, in that said guiding means are rollers (15) and in that said belt comprises two upper sides (12, 13) each having a said free extremity and a lower side (14) connecting these upper sides, wherein the lower side is guided over rollers (16) extending across the full width of the belt and wherein the free extremities of the upper sides are both connected to the apparatus. Cover device according to one of the preceding claims, wherein the belt being rigid in transverse direction comprises an oil proof material.

Inventors: BROUWERS SYTZE, VAN LEEUWEN JOHANNES TEODORUS, BROUWERS, SYTZE,, VAN LEEUWEN, JOHANNES TEODORUS,
Applicants: DUNLOP ENERKA BV, DUNLOP-ENERKA B.V.
Application year: 1990
Main classification: B23Q11
IPC codes: B23Q11