Adjustable guide roller suspension device

Abstract

 The present invention relates to an adjustable guide rail roller suspension device (10) for an industrial lift truck. The suspension device comprises a bracket (20) with attachment means (22) for attachment to an industrial lift truck, and a shaft retaining element (30) for attaching a roller shaft (40) to the bracket (20). In the present suspension device (10), the shaft retaining element (30) is adapted to be rotatably mounted to the bracket (20), where said rotation occurs around a first axis (A1). The shaft retaining element (30) comprises locking means (32) for securing the shaft retaining element (30) to the bracket (20) in one of a plurality of eligible rotational positions, and a shaft engagement portion (34). The shaft engagement portion (34) is arranged offset from said first axis (A1).

Description

TECHNICAL FIELD

[0001] The present invention pertains to an adjustable guide rail roller suspension device for an industrial lift truck, and to an industrial lift truck comprising such a device.

BACKGROUND ART

[0002] Industrial lift trucks are frequently employed for materials handling in e.g. factories and warehouses. Such lift trucks can be controlled automatically, by a variety of different control systems, or be controlled manually by operators.

[0003] Manually operated industrial lift trucks are essentially steered like any other wheeled vehicle, i.e. forward, backward and sideways. At some locations within the work place, however, it may be desirable to restrain the sideways movement of the industrial lift trucks. Such locations include aisles in warehouses, where the lift trucks are utilised to stack goods in racks. Here, so called guide rails can be arranged on the ground. In turn, cooperating guide rail rollers are mounted on the corner areas of the lift trucks, so that the lift trucks can be controlled sideways by the guide rollers engaging the guide rails. The lift trucks are thereby hindered from colliding with the racks.

[0004] The goods are commonly placed on pallets, and the pallets are delivered to, or retrieved from, the warehouse racks by means of the industrial lift trucks. By means of the guide rails and the guide rollers, the operator need not control the sideways movement of the lift truck, but may focus on the lifting operation.

[0005] In order to make the most of the available storage area, warehouse racks are often up to 10 meters high. When operating at such height, it is essential that any play between the guide rails and the guide rollers is minimised. Such play can otherwise make the lift truck travel along a zigzag path between the guide rails. The lift truck shall be firmly constrained by the guide rails. Further, guide rail arrangements of different warehouses differ from one another, both when it comes to actual dimensions and spatial placement of the guide rails. Thus, it is desirable to be able to laterally adjust the guide rolls of the industrial truck.

[0006] GB2110620 A describes an adjustable guide roller assembly. Here, a guide roller axle has a guide roller receiving portion and an end portion with a polygonal cross-section, where said end portion is offset in relation to the guide roller receiving portion. The three positions of the guide roller assembly can be changed between by loosening a bolt connection, removing the axle, turning the axle, reattaching the axle and finally tightening the bolt connection. This adjustment procedure is time-consuming, complex, and the final position of the guide roller cannot be seen until after the axle has been turned and reattached.

[0007] The object of the present invention is to provide an adjustable guide roller suspension device which is easy to use, reliable, cost-effective and offers adjustment in several steps.

SUMMARY OF THE INVENTION

[0008] The present invention relates to an adjustable guide rail roller suspension device for an industrial lift truck. The suspension device comprises a bracket with attachment means for attachment to an industrial lift truck, and a shaft retaining element for attaching a roller shaft to the bracket. In the present suspension device, the shaft retaining element is adapted to be rotatably mounted to the bracket, where said rotation occurs around a first axis. The shaft retaining element comprises locking means for securing the shaft retaining element to the bracket in one of a plurality of eligible rotational positions, and a shaft engagement portion. The shaft engagement portion is arranged offset from said first axis.

[0009] The offset arrangement of the shaft engagement portion with respect to the rotation axis of the shaft retaining element entails that rotation of the shaft retaining element results in displacement of the shaft engagement portion. Thus, by rotating the shaft retaining element, the roller shaft is displaced in relation to the industrial lift truck.

[0010] The present arrangement allows quick and simple adjustment of the suspension device. An operator only needs to release the locking means, turn the shaft retaining element, and then fasten the locking means. Neither the roller not the roller shaft must be removed. The adjustable feature entails that one suspension device can be used for a variety of different guide rail widths.

[0011] The design allows all components to be joined together in a positive form locking manner, which results in a sturdy, reliable and durable suspension device. Thereby, the guide rail roller endures very demanding operational circumstances such as mechanical impacts and heavy mechanical loads. Further, the suspension device can easily be retro-fitted to existing industrial lift trucks.

[0012] The fact that the shaft retaining element may be secured to the bracket in a plurality of rotational positions entails that fine tuning of the suspension device is possible. Alternatively, a large displacement of the roller shaft, from the innermost position to the outermost position, can also be realized.

[0013] The bracket may comprise means for rotatably mounting the shaft retaining element to the bracket. In a simple, yet reliable, form, such means can be a hole. Accordingly, the shaft retaining element may comprises a shaft retaining disc that can be received in said hole, whereas the shaft engagement portion is arranged on said shaft retaining disc. This corresponds to a plain and cost-effective solution, with high mechanical strength.

[0014] In this connection the shaft retaining element may further comprise a bracket engagement disc which is attached to the shaft retaining disc. The bracket engagement disc may comprise a radially protruding portion on which the locking means are arranged. Such bracket engagement disc makes the suspension device easy to adjust, and provides a reliable locking feature. The shaft retaining disc and the bracket engagement disc may be formed in one piece, which reduces the number of components. Alternatively, the shaft retaining disc and the bracket engagement disc can be two easily manufactured separate parts that are attached together.

[0015] A reliable suspension device can be ensured if the bracket comprises cooperating locking means that are adapted to cooperate with the locking means of the bracket engagement disc in a positive form locking manner. The locking means and the cooperating locking means may e.g. be holes, through which a locking pin or a locating bolt can be inserted.

[0016] The plurality of rotational positions for the bracket can be realized by providing a plurality of cooperating locking means, which are distributed such that the shaft retaining element can be locked in one of a plurality of eligible rotational positions. Each one of these positions corresponds to a certain distance between the roller shaft and the bracket.

[0017] A predictable and exact adjustment can be achieved if the plurality of cooperating locking means are distributed such that, when moving the locking means between any two neighbouring cooperating locking means, the roller shaft is displaced by the same increment from the bracket.

[0018] A spacer plate can be incorporated in the suspension device. Such a spacer plate can be placed between the attachment means and the industrial lift truck, in order to distance the bracket away from the industrial lift truck. By incorporating one or more spacer plates, one and the same suspension device can be used for a greater variety of different guide rail widths.

[0019] The present invention further relates to an industrial lift truck that comprises the above described adjustable guide rail roller suspension device.

BRIEF DESCRIPTION OF THE FIGURES

[0020] Below, an exemplary embodiment of the present invention is described. References are made to the enclosed figures, where

fig 1

shows an industrial lift truck with two guide rail rollers 1 on each side, and two guide rails 5a, 5b,

fig 2

is an exploded view of the suspension device components, a roller 42 and a roller shaft 40,

fig 3

shows the dismantled components of the suspension device,

fig 4

is a perspective view of the suspension device with a mounted roller, and

fig 5a-c

is a view from above of the assembled suspension device with the roller in three different positions.

DETAILED DESCRIPTION

[0021] Figure 1 shows a typical example of an industrial lift truck, in this case a so called very narrow aisle truck, with guide rail rollers 1. The guide rail rollers 1 cooperate with two vertical guide rails 5a, 5b, which are arranged in parallel on the ground on which the industrial lift truck operates. In the illustration of figure 1, the industrial lift truck is about to enter between the guide rails 5a, 5b. Once flanked by the guide rails 5a, 5b, the truck operator need and can not control the sideways movement of the industrial truck.

[0022] Figure 2 is an exploded view of a guide rail roller suspension device 10. The purpose of the suspension device 10 is to vertically support a guide roller of an industrial lift truck, so that the guide roller can cooperate with vertical guide rails 5a, 5b. The guide rail roller suspension device 10 is adjustable, which means that the guide roller can be displaced laterally with respect to the industrial lift truck. More precisely, the roller shaft can be shifted between a plurality of positions, all of which are arranged at different horizontal distances from the industrial lift truck, see figure 5.

[0023] The suspension device 10 comprises a bracket 20 and a shaft retaining element 30. Shown in figure 2 are also a roller 42 and roller shaft 40, which do not form part of the present invention. The roller 42 is carried by the roller shaft 40 which, in turn, is carried by the bracket 20 via the shaft retaining element 30. An assembled suspension device is shown in figure 4.

[0024] The bracket 20 is made up by an attachment plate 22 and a frame-like casing that protrudes perpendicularly from the attachment plate 22. The attachment plate 22 comprises bolt holes by means of which the bracket 20 can be bolted to the side on an industrial lift truck. The attachment plate 22 may also be formed in one piece with the industrial truck, or be welded to the latter. The frame like casing comprises four side walls, two 24a, 24b of which are designed for supporting the roller shaft 40. When mounted to an industrial lift truck, the attachment plate 22 extends in a vertical plane, and the frame-like casing protrudes in a horizontal direction.

[0025] Instead of the frame like casing with the side walls 24a, 24b, an upper and a lower roller shaft supporting member (not shown) may protrude from the attachment plate 22. Such shaft supporting members may be of arbitrary form, as long as they fulfil the purpose of rigidly supporting the roller shaft 40. E.g. the shaft supporting members may be in the form of cantilevers.

[0026] As is illustrated, the roller shaft 40 is carried by first and second, or upper and lower, horizontal side walls 24a, 24b of the frame like casing of the bracket 20. For the sake of simplicity, the attachment of the roller shaft 40 to the first and second side walls 24a, 24b will be described with reference to the first, or upper, side wall 24a only.

[0027] The upper side wall 24a of the bracket 20 comprises a circular hole 26a in which a part of the shaft retaining element 30 is pivotally guided. More in detail, the shaft retaining element 30 includes a shaft retaining circular disc 36, which can be rotatably received within the circular hole 26a. The shaft retaining element 30 further includes a bracket engagement disc 38 with a through hole 32 that functions as a locking means. In this example, the bracket engagement disc 38 is essentially drop-shaped and the through hole 32 runs through the apex of the drop. Said apex protrudes radially with respect to the periphery of the circular disc. The circular disc 36 and the bracket engagement disc 38 can be formed in one piece, or may be bolted together by a connecting bolt 52, as illustrated in the figures.

[0028] Now, the roller shaft 40 can be introduced into a shaft engagement hole 34, arranged off-centre through the circular disc 36. Bearing in mind that the circular disc is rotatably received within the circular hole 26a, it is to be appreciated that the roller shaft 40 is shifted in the horizontal direction upon rotation of the circular disc 36. The circular disc 36 is rotated by rotating the bracket engagement disc 38. Said rotation can be hindered by means of the locking means 32 of the bracket engagement disc 38. As is illustrated, the rotation of the bracket engagement disc 38 is blocked by means of a locating bolt 50 that runs through the radially protruding portion of the bracket engagement disc 38. Said protrusion butts against the top surface of the upper side wall 24a. The locating bolt is received within one of a plurality of threaded locating holes 28a1, 28a2, 28a3, 28a4, 28a5 which are distributed around the circular hole 26a that receives the circular disc 36.

[0029] By removing the locating bolt 50 and rotating the shaft retaining element 30, the horizontal position of the guide roller 42 can be changed. Figure 5 illustrates the innermost (figure 5a) and the outermost (figure 5c) positions of the guide roller 42. By innermost position is meant the position that is closets to the attachment plate 22, i.e. to the industrial lift truck. In the present example, the shaft retaining element 30 can be locked in five different positions. For each position, a locating hole 28a1, 28a2, 28a3, 28a4, 28a5 for the locating bolt 50 is provided in the upper side wall 24a. Thus, the bracket engagement disc 38 is rotated until the through hole 32 is aligned with one of the locating holes, which corresponds to the desired horizontal position of the roller 42, and then the locating bolt 50 is used to secure the position of the bracket engagement disc 38. Thereby, a reliable positive form locking connection is obtained. The rotation of the shaft retaining element 30 is easily performed by hand by grasping the bracket engagement disc 36. The fact that the bracket engagement disc 38 is drop-shaped makes it easy to handle.

[0030] The bracket engagement disc 38 is preferably shaped so as to provide a good grip when the roller 42 is adjusted. E.g., the bracket engagement disc 38 may be polygonal. However, in its easiest form, bracket engagement disc 38 is circular and has a diameter that exceeds the diameter of the shaft retaining circular disc 36. The through hole 32 is arranged in the portion of the bracket engagement disc 38 that extends outside the shaft retaining disc 36, so that the locating bolt 50 can secure the position of the bracket engagement disc 38 by engaging a locating hole.

[0031] The circular hole 26a, which acts as a means 26a for rotatably mounting the shaft retaining element 30, may take other forms. This is true also for the circular disc 36 of the shaft retaining element 30, as long as the shaft retaining element 30 is rotatably connected to the bracket 20. E.g., the hole 26a may be a polygonal, and the disc 36 circular, or vice versa. Also, the rotatable joint between the bracket 20 and the shaft retaining element 30 can be a pin connection. A positive form fit between the shaft retaining element 30 and bracket 20, restraining the radial movement of the shaft retaining element 30 with respect to the bracket 20 in a play/free manner, ensures good stability and high reliability of the roller suspension.

[0032] Figure 3 illustrates the components of the present suspension device. In connection with the bracket 20 and the shaft retaining circular disc 36, a first axis A1, around which the shaft retaining element 30 can be rotated, is clearly indicated. Also, a second axis A2, around which the roller 42 rotates, is drawn through the shaft engagement hole 34 of the shaft retaining disc 36. The fact that the shaft engagement hole 34 is eccentric with respect to the shaft retaining circular disc 36 entails that rotation of the shaft retaining circular disc 36 results in displacement of the roller shaft 40.

[0033] As is indicated in figure 2, two shaft retaining elements 30 are used for suspending the roller shaft 40. One shaft retaining element 30 is mounted to the upper side wall 24a, and another shaft retaining element 30 is mounted to the lower side wall 24b. The shaft retaining discs 36 of the shaft retaining elements 30 are arranged within respective openings 26a, 26b in the side walls 24a, 24b. One of the bracket engagement discs 38 is arranged on the upper side of the upper side wall 24a, and the other bracket engagement disc 38 is arranged on the under side of the under side wall 24b.

[0034] The roller shaft 40 runs through the shaft engagement hole 34 of the shaft retaining disc 36 and abuts against the bracket engagement disc 38. A shaft fixing bolt 54 runs through a hole in the bracket engagement disc 38 and engages a thread in the roller shaft 40.

[0035] Two different roller shafts 40, 40' are shown in figure 3. The shorter roller shaft 40 is the one that is employed in figures 2 and 4, where the roller 42 is arranged in-between the upper and lower side walls 24a, 24b of the bracket 20. When the longer shaft 40' is mounted between the upper and lower side walls 24a, 24b of the bracket 20, a roller 42 supporting portion 44' extends through the lower side wall 24b and protrudes from the underside of the lower side wall 24b. Thus, by means of the present bracket 20 design and the longer roller shaft 40', the roller 42 can be arranged below (not shown) the bracket 20. This is desired when the roller 42 is to bear against relatively low guide rails 5a, 5b, and/or when the bracket 20 is mounted at an elevated position on the industrial truck. An alternative bracket engagement disc 38' is provided for mounting the roller 42 underneath the bracket 20, see figure 3. The alternative bracket engagement disc 38' is mounted on the upper side of the lower sidewall 24b, and comprises a recess 46' through which the longer roller shaft 40' can pass.

[0036] Four spacer washers 60 are also shown I figure 2. These can be used to locate the roller 42 at a higher or lower vertical position along the roller shaft 40.

[0037] A spacer plate (not shown) can be used to distance the bracket 20 away from the industrial lift truck. Such a spacer plate is arranged between the lift truck and the attachment plate 22. By means of one or more such spacer plates, one and the same bracket 20 can be used to locate the roller 42 at a variety of different horizontal distances from the industrial lift truck. The spacer plate has a form that essentially corresponds to the attachment plate 22 of the bracket 20.

[0038] The shape of the upper and lower side walls 24a, 24b of the bracket are clearly illustrated in figures 3 and 5. The sidewalls 24a, 24b include an essentially semicircular bulge, in the centre of which the openings 26a, 26b for rotatably mounting the shaft retaining element 30 are arranged. Around said openings 26a, 26b, the five locating holes 28a1, 28a2, 28a3, 28a4, 28a5 are distributed in a circle such that the shaft retaining element 30 can be locked in one of a plurality of eligible rotational positions. As is shown in figure 5, each eligible rotational position corresponds to a certain horizontal distance between the roller 42 and the bracket attachment plate 22. The five locating holes are distributed such that the roller 42 is displaced by the same increment from the bracket attachment plate 22, when the shaft retaining element 30 is moved between any two neighbouring locating holes. A rotation of 60° corresponds to moving the shaft retaining element 30 from the first locating hole 28a1 to the second locating hole 28a2, and from the fourth locating hole 28a4 to the fifth locating hole 28a5. The angular distances between the other locating holes 28a2→28a3, 28a3→28a4 are 30° each. In total, the angular distance between the first and the fifth locating holes 28a1, 28a5 is 180°. A more delicate adjustment of the suspension device 10 can be achieved by providing a greater number of locating holes around the openings 26a, 26b for rotatably mounting the shaft retaining element 30.

[0039] In the present example, the roller 42 is displaced by 2.5 mm in the horizontal direction, towards or away from the industrial truck, when the shaft retaining element 30 is moved between two neighbouring locating holes. Thereby, the suspension device can be used to compensate for wear of the roller 42. If larger dimensions are used, and/or by increasing the offset of the shaft engagement portion with respect to the rotation axis of the shaft retaining element, the adjustment steps can be increased which results in a broader application range for the suspension device.

Claims

1. An adjustable guide rail roller suspension device (10) for an industrial lift truck, which suspension device comprises

- a bracket (20) with attachment means (22) for attaching the bracket (20) to an industrial lift truck, and

- a shaft retaining element (30) for attaching a roller shaft (40) to the bracket (20),

characterised in that said shaft retaining element (30) is adapted to be rotatably mounted about a first axis (A1) to the bracket (20), and comprises

- locking means (32), for securing the shaft retaining element (30) to the bracket (20) in one of a plurality of eligible rotational positions, and

- a shaft engagement portion (34), which is arranged offset from said first axis (A1).

2. The device of claim 1, wherein the bracket (20) comprises means (26a, 26b) for rotatably mounting the shaft retaining element (30) to the bracket (20).

3. The device of claim 2, wherein the means (26a, 26b) for rotatably mounting the shaft retaining element (30) to the bracket (20) is a hole (26a, 26b), and the shaft retaining element (30) comprises a shaft retaining disc (36) that can be received in said hole (26a, 26b), the shaft engagement portion (34) being arranged on said shaft retaining disc (36).

4. The device of claim 3, wherein the shaft retaining element (30) further comprises a bracket engagement disc (38) which is attached to the shaft retaining disc (36), which bracket engagement disc (38) comprises a radially protruding portion on which the locking means (32) are arranged.

5. The device of claim 4, wherein the shaft retaining disc (36) and the bracket engagement disc (38) are formed in one piece.

6. The device of claim 4, wherein the shaft retaining disc (36) and the bracket engagement disc (38) are two separate parts that are attached together, e.g. by means of a bolt connection.

7. The device of any one of claim 1 to 6, wherein the bracket (20) comprises cooperating locking means (28a1-28a5, 28b1-28b5), which are adapted to cooperate with the locking means (32) of the shaft retaining element (30) in a positive form locking manner.

8. The device of claim 7, wherein the bracket (20) comprises a plurality of cooperating locking means (28a1-28a5, 28b1-28b5), which are distributed such that the shaft retaining element (30) can be locked in one of a plurality of eligible rotational positions.

9. The device of claim 8, wherein each eligible rotational position corresponds to a certain distance between the roller shaft (40) and the bracket (20).

10. The device of claim 9, wherein the plurality of cooperating locking means (28a1-28a5, 28b1-28b5) are distributed such that, when the locking means (32) of the shaft retaining element (30) is moved between any two neighbouring cooperating locking means (28a1-28a5, 28b1-28b5), the roller shaft (40) is displaced by the same increment from the bracket (20).

11. The device of any one of claim 7 to 10, wherein the cooperating locking means (28a1-28a5, 28b1-28b5) are distributed in a circle around a first axis (A1).

12. The device of any preceding claim, wherein the shaft retaining element (30) can be secured to the bracket (20) in five different rotational positions in a positive form locking manner.

13. The device of any preceding claim, wherein the bracket (20), when mounted, comprises an upper and a lower shaft supporting member (24a, 24b), which protrude from the attachment means (22), whereby the upper shaft supporting member (24a) is adapted to support the upper end of the roller shaft (40) and the lower shaft supporting member (24b) is adapted to support the lower end of the roller shaft (40).

14. The device of any preceding claim, which device further comprises a spacer plate, which is adapted to be placed between the attachment means (22) and the industrial lift truck.

15. An industrial lift truck comprising an adjustable guide rail roller suspension device (10) according to any preceding claim.

Drawing