GB2199298A

GB2199298A - Tubular-belt type conveyor

Info

Publication number: GB2199298A
Application number: GB08729620A
Authority: GB
Inventors: Kunio Hashimoto; Haruo Okazaki
Original assignee: Bridgestone Corp
Current assignee: Bridgestone Corp
Priority date: 1986-12-23
Filing date: 1987-12-18
Publication date: 1988-07-06
Also published as: GB8729620D0; ZA879634B; JPS63262320A; AU8281987A

Abstract

A tubular belt-type conveyor comprises first and second end rollers (2) spaced apart from each other along the length of the conveyor device, and an endless conveyor band (1) of flexible material movable along upper and lower conveyor paths between the rollers and engageable in flat form with the cylindrical outer surfaces of the rollers (2) as it passes from one conveyor path to the other. Guide means (4, 5, 6) are arranged alongside the upper conveyor path to engage the flat form of the conveyor band (1) and to form it into generally tubular shape, and to maintain the tubular shape as the conveyor band moves along the upper conveyor path. The relative arrangement of the guide means (4, 5, 6) and the second roller (2) is such that the region of engagement (2a) of the second roller with the flat form of the conveyor band on the upper conveyor path is located above the prolongation of the longitudinal axis L of the tabular shape of the conveyor band. This arrangement improves the stress distribution in the conveyor band as it undergoes transformation between flat and tubular form, by preventing a U-shaped portion of the band from being inclined, or a flat part of the band sliding to one side of the second roller. A roller elevating device is provided to adjust the height of the second roller (2) relative to the upper conveyor path. <IMAGE>

Description

TUBULAR-BELT TYPE CONVEYOR This invention relates to an endless conveyor device which comprises first and second rollers spaced apart from each other along the length of the conveyor device, an endless conveyor band or belt of flexible material which is movable along upper and lower conveyor paths between the rollers and which is engageable in flat form with the cylindrical outer surfaces of the rollers as it passes from one conveyor path to the other, and guide means arranged alongside the upper conveyor path so as to engage the flat form of the conveyor band as it leaves the first roller and to form the conveyor band into generally tubular shape, to maintain the tubular shape as the conveyor band moves towards the second roller along the upper conveyor path, and to cause or to permit unfolding of the conveyor band to flat form adjacent to the second roller.

A known construction of tubular belt-type conveyor will now be described with respect to Figures 5 to 8.

Figure 5 shows a tubular belt conveyor schematically wherein flattened parts at the front and rear ends of an endless conveyor belt 1 are wound around a front end roller 2 and a rear end roller 3, and the belt 1 circulates in the direction of the arrow by the front end roller 2 which is rotated by drive means (not shown).

In the vicinity of both the rollers 2 and 3, a first rolling-up frame 4 and.a second rolling-up frame 5 are located, and a plurality of belt shape maintaining frames 6 are disposed between the two second rolling-up frames 5 and 5.

As shown in Figure 7, at the upper part of the first rolling-up frame 4, three rolling-up. rollers 7a are arranged like a trapezoid, while at the upper part of the second rolling-up frame 5, three rolling-up rollers 7b are arranged in U shape. The lower parts of both the rolling up frames 4 and 5 are symmetrical to the upper parts in a vertical direction. As shown in Figure ó, at the upper and lower parts of each belt shape maintaining frame 6, there is provided a circular opening 8 through which the tubular conveyor belts rolled-up as described below passes. Around the opening 8, a plurality of belt shape maintaining rollers 9 are disposed in a circle.

The frames 4, 5 and 6 comprise guide means arranged alongside at least the upper conveyor path so as to engage the flat form of the conveyor band/belt as it leaves the front roller 3 and to form the conveyor band into generally tubular shape, to maintain the tubular shape as the conveyor band moves towards the second roller 2 along the upper conveyor path and to cause or to permit unfolding of the conveyor band to flat form adjacent to the second roller 2.

As shown in Figure 5 schematically, the flattened conveyor belt 1 which comes from the lower position around the rear end roller 3 wraps material 11 to be conveyed (which falls from a hopper 1) before it is rolled-up into a tubular shape and through the first and second rolling-up frames 4 and 5. Then, the belt 1 passes through the upper opening 8 of each belt shape maintaining frame 6 and opens to a flat shape, from which the conveyed material 11 is ejected onto a receiver 12. It is rolled-up into a tubular shape again, passes through the lower opening 8 and comes back to the rear end roller 3 for circulation.

At the open portion in the conventional tubular belt conveyor, as shown in Figure 8, the upper belt-engaging surface 2a of the front end roller 2 (which contacts the flat or opened conveyor belt 1) is positioned on the line extended from the longitudinal axis L of the tubular conveyor belt 1 so that the central part la and both the sides lb of the opened belt 1 are liable to lengthen uniformly by the tractive force of the front end roller 2.

The relationship between the rear end roller 3 and the conveyor belt 1 is similar to what is described with respect to the front end roller 2 and therefore is omitted.

In the conventional tubular belt conveyor, both the sides lb of the conveyor belt 1 which is rolled-up in the vicinity of the opened portion are not continuously connected, but are overlapped. Thus, the stress of both the ends lb and Ib occurs independently and the stress distribution is not uniform. Accordingly, even slight twisting of the conveyor belt 1 causes difference in stress between the two sides lb, whereby the elongation of each side is liable to be different, the U-shaped open portion is liable to be inclined, or the flat part on the end roller is liable to slide -towards one side.

The present invention has therefore been developed primarily, though not exclusively, with a view to overcome the disadvantages of the known tubular belt-type conveyors, and to improve the stress distribution in the conveyor belt or band as it undergoes transformation between flat and tubular form.

According to one aspect of the invention there is provided an endless conveyor device comprising: first and second rollers spaced apart from each other along the length of the conveyor device; an endless conveyor band of flexible material which is movable along upper and lower conveyor paths between the two rollers and which is engageable in flat form with the cylindrical outer surfaces of the rollers as it passes from one conveyor path to the other; and guide means arranged alongside the upper conveyor path so as to engage the flat form of the conveyor band as it leaves the first roller and to form the conveyor band into generally tubular shape, to maintain the tubular shape as the conveyor band moves towards the second roller along the upper conveyor path, and to cause or to permit unfolding of the conveyor band to flat form adjacent to the second roller; in which the relative arrangement of the guide means and the second roller is such that the region of engagement of the second roller with the flat form of the conveyor band on the upper conveyor path is located above the prolongation of the longitudinal axis of the tubular shape of the conveyor band.

In an embodiment of conveyor according to the invention, between any part of the conveyor belt or band and the engaging surface of the second roller, the distance along the central part of the band is longer than that along the sides, and therefore the central part is subjected to a larger tractive force. However, the central part has built-in larger anti-tractive resistance, and is therefore resistant to elongation. Therefore, the elongation decreases as a ole. Also, the difference in length between the two sides decreases, whereby the flattened conveyor band does not slide towards one side when it comes onto the second roller.

According to a further aspect of the invention there is provided a tubular belt-type conveyor which comprises an endless belt which can be rolled up into a tubular shape to wrap and convey material, a front end roller, a rear end roller, the flattened ends of the belt being wound around the two rollers so that the belt may circulate continuously and roller elevating means for adjusting the height of one of said end rollers, said roller elevating means comprising a bearing for said one end roller, a screw rod secured to the bearing, a guide member within which the screw rod is movable up and down, a support member secured to the guide member, a generally horizontally extending female screw plate provided at the upper end of the support member to engage with the screw rod and a handle at the top of the screw rod to move the latter within the guide.

Embodiments of tubular belt-type conveyor according to the invention will now be described in detail, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a side view showing the flattened portion of a tubular belt-type conveyor according to the present invention; Figure 2 is a schematic side view showing one embodiment of a roller elevating device according to the present invention; Figure 3 is a vertical sectional view of another embodiment of a conveyor belt to which the present invention is applicable; Figure 4 is a vertical sectional. view of further embodiment of a belt conveyor to which the present invention is applicable; Figure 5 is a schematic side view showing a conventional tubular belt conveyor; Figure 6 is an enlarged sectional view taken along line A-A in Figure 5;; Figure 7 is an enlarged plan view of the beginning part of a return path in Figure 4, and, Figure 8 is similar to Figure 1 and a side view of the conventional tubular belt conveyor.

The present invention will be described in detail with respect to preferred embodiments shown in Figures 1 to 4, in which the same numerals identify corresponding parts in Figures 5 to 8, illustrating the conventional tubular belt conveyor.

Figure 1 is one embodiment of a belt-opened portion in a tubular belt conveyor according to the present invention.

In the present invention, as shown in Figure 1, the upper belt-engaging surface 2a of the front end roller 2 is higher tan the central axis L of the rolled-up tubular portion of a conveyor belt 1, and may be preferably positioned on the line extended from the overlapped portion of both the sides lb. Accordingly, between a flattened beginning point, such as within a belt shape maintaining frame 6 in Figure 1, and the end surface 2a, the distance along their sides lb is shorter than that along the central part la.

The front end roller 2 is fixed as shown in the embodiment mentioned above, but may be adjusted in its height by a roller elevating device as shown in Figure 2, in which a bearing 13 for the front end roller 2 is fixed to a screw rod 16 which is movable up and down within a guide member 15 secured to a support member 14. At the upper end of the support member 14, there is a horizontally extending female screw plate 17 which engages with the screw rod 16. By rotating a handle 18 at the top of the screw rod 16, the rod 16 rises and falls, whereby the roller 2 goes up and down. The roller elevating device may also be provided at a rear end roller 3.

This embodiment relates to a tubular belt conveyor in which a flat belt or band of flexible material is rolled-up into a tubular shape by overlapping the inner surface of one side end on the outer surface of the other side end along its entire length, but the present application is also applicable to a tubular belt conveyor in which a conveyor belt 31 is rolled up by contacting the inner surfaces oE the side ends with each other as shown in Figure 3 by abutting or approaching the side edges with each other.

Figure 4 shows another embodiment of a tubular belt conveyor in which a tubular belt 41 is supported by six support rollers 42. Three upper support rollers 42 are connected by an upper link 43, while three lower rollers 42 are connected by a lower link 44. The upper and lower links 43 and 44 are supported at the side ends by a Ushaped support cradle frame 45. The present application may be applicable to this embodiment as well.

As mentioned above, between any part of the conveyor belt at the beginning point of the opening and the engaging surface of the end roller, the distance along the sides is shorter than that along the central part in the conveyor belt. Accordingly, the central part having greater anti traction resisting force is subject to the largest traction force by the roller, and the elongation at the side ends is not so large as that at the central part, and the absolute value of the difference in stress at the sides can be considerably small compared with that at the central part.

Therefore, the difference in elongation between the two sides of the conveyor belt can become as small as possible, and it prevents the trough portion from being inclined or the flattened portion from sliding towards one side on the end roller. Further, as mentioned in the embodiments above, the engaging surface of the roller -is positioned on the line extended from the overlapping portion of the side ends of the tubular conveyor belt, whereby the elongation at the sides becomes substantially zero.

Claims

1. An endless conveyor device comprising: first and second rollers spaced apart from each other along the length of the conveyor device; an endless conveyor band of flexible material which is movable along upper and lower conveyor paths between the two rollers and which is engageable in flat form with the cylindrical outer surfaces of the rollers as it passes from one conveyor path to the other; and guide means arranged alongside the upper conveyor path so as to engage the flat form of the conveyor band as it leaves the first roller and to form the conveyor band into generally tubular shape, to maintain the tubular shape as the conveyor band moves towards the second roller along the upper conveyor path, and to cause or to permit unfolding of the conveyor band to flat form adjacent to the second roller; in which the relative arrangement of the guide means and the second roller is such that the region of engagement of the second roller with the flat form of the conveyor band on the upper conveyor path is located above the prolongation of the longitudinal axis of the tubular shape of the conveyor band.

2. A conveyor according to Claim 1, in which the guide means is arranged to roll-up the conveyor band into tubular form by overlapping the opposed edges of the band.

3. A conveyor according to Claim 1, in which the guide means is arranged to roll-up the conveyor band into tubular form by bringing the opposed edges of the band into abuttment.

4. A conveyor according to any one of the preceding claims, in which the guide means includes a first pair of folder roller arrangements adjacent to the first roller and operable to apply progressive inward folding to the flat form of the band as it leaves the first roller, a second pair of folder roller arrangements adjacent to the second roller and operable to cause or to permit progressive unfolding of the tubular shape to flat form, and rollertype retaining frames spaced apart along the length of the conveyor band between said first and second pairs of folder roller arrangements in order to maintain the tubular shape of the conveyor band.

5. A conveyor according to any one of the preceding claims, in which the guide means is operative on the upper and lower conveyor paths of the conveyor band.

6. A conveyor according to Claim 1 or 2, in which the guide means comprises a plurality of rollers which are connected by upper and lower links and which are mounted on a supporting cradle frame.

7. A conveyor according to any one of the preceding claims, including an adjustment device for adjusting the height of said second roller relative to the upper conveyor path.

8. A tubular belt-type conveyor which comprises an endless belt which can be rolled up into a tubular shape to wrap and convey material, a front end roller, a rear end roller, the flattened ends of the belt being wound around the two rollers so that the belt may circulate continuously and roller elevating means for adjusting the height of one of said end rollers, said roller elevating means comprising a bearing for said one end roller, a screw rod secured to the bearing, a guide member within which the screw rod is movable up and down, a support member secured to the guide member, a generally horizontally extending female screw plate provided at the upper end of the support member to engage with the screw rod and a handle at the top of the screw rod to move the latter within the guide.

9. A tubular belt-type conveyor according to Claim 8, including guide means arranged to roll-up the conveyor belt by overlapping the inner surface of one side edge on the outer surface of the other side edge along its entire surface.

10. A tubular belt-conveyor according to Claim 8, including guide means arranged to roll-up the conveyor belt by contacting the inner surfaces of the side edges with each other along their entire length.

11. A tubular belt-type conveyor according to Claim 8, including a plurality of rollers for supporting the conveyor belt and which are connected by an upper and a lower link, the upper link being connected with the lower link through the arms of a support frame.

12. A conveyor according to Claim 1 or 8 and substantially as hereinbefore described with reference to, and as shown in the accompanying drawings.