IES58902B2 - A trailer - Google Patents

Description

The present invention relates to a trailer, and in particular, though not limited to a soft terrain trailer.

It is regularly necessary to tow a trailer over a soft marshy terrain, for example, over a .bog, through forestry or the like. Trailers are extensively used for drawing felled timber.from forests where the terrain is relatively soft and in many cases rough also. A practice has recently developed where batch quantities of wet peat excavated from a bog are extruded onto the surface of a bog for drying to subsequently form sods of turf. This practice requires a trailer comprising an extruder being towed over the bog surface. Excavated wet peat is loaded into the trailer which is subsequently extruded onto the surface of the bog for subsequent drying on each pass as the trailer is being trailed. Depending on the construction of the extruder one or more elongated extrusions are formed on each pass of the trailer over the bog surface. As the extrusion or extrusions are being delivered from the extruder, they are transversely marked at predetermined intervals to facilitate breaking of the peat extrusion when dry for forming turf sods. In such cases, either in forestry s 5 890 2 or bog use, the trailer is generally towed by a , tractor. To avoid the trailer sinking and becoming r stuck in the soft terrain, the trailers are normally tracked trailers having four wheels, namely, a pair of front wheels and a pair of rear wheels. Ground engaging tracks are provided extending between and around respective front and rear wheels on opposite sides of the trailer. In excessively marshy ground the front and rear wheel may be replaced by a double wheel and correspondingly wider tracks may be provided.

While the provision of tracks and double wheels on a trailer is in general sufficient to prevent the trailer sinking in marshy ground, unfortunately, the additional load of the trailer on the tractor causes the tractor to sink and become stuck in marshy ground. Even the provision of double front and rear wheels on the tractor in most cases is insufficient to avoid the rear driven wheels of the tractor becoming stuck in marshy ground. There is therefore a need for a trailer which overcomes this problem.

The present invention is directed towards providing j such a trailer.

According to the invention there is provided a trailer comprising a chassis, at least two ground engaging wheels rotatably mounted on the chassis, hitch means extending from the chassis for hitching the trailer to a towing vehicle, and drive transmission means for transmitting drive from a power-take-off shaft of the towing vehicle for driving at least one of the ground engaging wheels, the drive transmission means comprising an input means for connection to the powertake-off shaft of the towing vehicle and an output means operably connected to at least one ground engaging wheel, a free-wheel clutch means provided in the drive transmission means between the input means and the output means for permitting drive in one rotational direction to be transmitted from the input means to the output means, and for preventing drive in that one rotational direction being transmitted from the output means to the input means.

Advantageously, the free-wheel clutch means comprises a free-wheel clutch.

Preferably, isolating clutch means is provided in the drive transmission means for isolating the input means from the output means. Advantageously, the isolating clutch means is provided intermediate the free-wheel clutch means and the output means.

In one embodiment of the invention the drive transmission means comprises a first drive shaft driving a second drive shaft through the free-wheel clutch means.

In another embodiment of the invention two of the ground engaging wheels are driven through a differential drive unit. Preferably, the output means comprises an output drive shaft connected to the differential unit for driving the differential unit, the output drive shaft receiving drive from the second drive shaft. Advantageously, a first drive element is rigidly mounted on and co-axial with the second drive shaft and is operably connected to a second drive element co-axial with the output drive shaft and freely rotatable relative to the output drive shaft.

Preferably, the isolating clutch means transmits drive from the second drive element to the output drive shaft. In a further embodiment of the invention the isolating clutch means comprises a third drive element 20 co-axially mounted on the output drive shaft and in driving engagement therewith, the third drive element being slidable on the output drive shaft from a disengaged position disengaged from the second drive element isolating drive to the output drive shaft, to 25 an engaged position engaging the second drive element with drive being transmitted through the isolating clutch means to the output shaft, and means for moving » the third drive element between the disengaged and J engaged positions. Preferably, the means for moving the third drive element on the output drive shaft comprises an hydraulic ram. Advantageously, the hydraulic ram is operably connected to the third drive element through an operating lever.

In another embodiment of the invention biasing means are provided for biasing the third drive element into the disengaged position. Preferably, the biasing means comprises a tension spring.

Advantageously, the first and second drive elements are provided by respective sprockets operably connected by a drive chain.

In another embodiment of the invention the input means comprises an input shaft rotatably mounted on the chassis, the input shaft being operably connected to the first drive shaft.

In a further embodiment of the invention four ground engaging wheels are provided and ground engaging tracks extend around pairs of spaced apart wheels on opposite sides of the trailer. Preferably, two front wheels on opposite sides of the trailer adjacent the * front thereof are driven.

Preferably, the trailer comprises a container body. Advantageously, an extruder communicating with the container body is provided for extruding material from the container body. Preferably, the extruder is adapted for extruding peat.

The invention will be more clearly understood from the following description of a preferred embodiment thereof given by way of example only with reference to the accompanying drawings in which: Fig. 1 is a front perspective view of a trailer according to the invention, Fig. 2 is a front perspective view of the trailer of Fig. 1 from the other side, Fig. 3 is a rear perspective view of the trailer of Fig. 1, Fig. 4 is a plan view of portion of the trailer of Fig. 1, Fig. 5 is a cut away perspective view of the portion of Fig. 4, Fig. 6 is a sectional plan view of a detail of the trailer of Fig. 1, and Fig. 7 is a sectional plan view of the detail of Fig. 6 in a different position.

Referring to the drawings there is illustrated a trailer according to the invention indicated generally by the reference numeral 1. The trailer 1 is particularly suitable as a soft or rough terrain vehicle, and in this embodiment of the invention is suitable for extruding peat in elongated extrusions onto a bog for drying for the subsequent formation of turf sods. The trailer 1 comprises a main chassis 3 comprising a pair of spaced apart elongated side members 4 and 5 and front and rear end members 6 and 7, respectively. An arm 8 connected to the front end member 6 and reinforced by reinforcing members 9 and extending forwardly therefrom carries a tow hitch 10 for hitching the trailer 1 to a towing vehicle, for example, a tractor (not shown). A sub-chassis 11 mounted on the main chassis 3 supports a container body 12 for storing wet peat for subsequent extrusion into peat extrusions as will be described below.

Four ground engaging wheels, namely, a pair of front ground engaging wheels 15 and a pair of rear ground engaging wheels 16 are mounted on the main chassis 3. Tracks 18 are provided around and between respective 5 front and rear wheels 15 and 16 to prevent the trailer sinking into the soft or rough terrain. In this embodiment of the invention each front and rear wheel 15 and 16 is provided by double pneumatic wheels 19. The rear ground engaging wheels 16 are freely rotatable on a shaft 20 mounted on the main chassis 3.

The front ground engaging wheels 15 are mounted on a differential drive axle unit 22 mounted on the main chassis 3 and are driven through drive transmission means (described below) from the power-take-off shaft 15 (not shown) of the tractor (not shown) to reduce the towing load of the trailer on the tractor, and thus, reduce the risk of the tractor sinking in the soft terrain. Suitable mounting suspensions (not shown) are provided for mounting the shaft 20 and the differential drive axle unit 22 to the main chassis 3.

Such suspension mountings will be well known to those skilled in the art.

Referring in particular to Figs. 4 and 5, the drive transmission means for driving the front wheels 15 25 comprises an input means and an output means, namely, an input shaft 25 and an output shaft 26, respectively. The input shaft 25 extends from a gear box 28 mounted on the main chassis 3. Splines 29 are provided on the input shaft 25 for engaging a drive shaft (not shown) for connecting the input shaft 25 to the power-take--off shaft (not shown) of the tractor. The output shaft 25 is coupled to the differential unit 22 by a pair of coupling flanges 30 on the output shaft 25 and an input shaft 27 of the differential unit 22 for driving the differential unit 22 and in turn the front wheels 15. A pair of support members 31 extending between the side members 4 and 5 of the chassis 3 rotatably carry the output shaft 26. The output shaft 25 is rotatable in bearings 32 carried by the support members 31. Suitable suspension mountings (not shown) are provided for mounting the support members 31 to the chassis 3 to accommodate relative movement of the shaft 26 caused by movement by the differential axle unit 22 relative to the chassis 3. Splines 33 are provided at the free end of the output shaft 26 for receiving drive as will be described below.

A first drive shaft 35 of the drive transmission means is coupled to an output (not shown) of the gear box 28 and is driven by the input shaft 25 through the gear box 28. The gear ratio of the gear box 28 from the input shaft 25 to the first drive shaft 35 is a step down ratio of 5:1. A support bracket 37 mounted on the side member 5 of the main chassis 3 rotatably supports the first drive shaft 35 in bearings 38. A second drive shaft 40 of the transmission means is rotatably supported in bearings 41 in support brackets mounted on the side member 5, and is driven by the first drive shaft 35 through a free-wheel clutch means, namely, a free-wheel clutch 43 of gear ratio 1:1. The free-wheel clutch 43 permits drive in one rotational direction from the first drive shaft 35 to the second drive shaft 40, and prevents drive in that rotational direction from the second drive shaft 40 to the first drive shaft 35. Accordingly, should the front wheels 15 rotate the second drive shaft 40 faster than the first drive shaft 35 is being driven by the power-take-off shaft (not shown) the free-wheel clutch 43 prevents drive being transmitted to the first drive shaft 35. Thus any danger of damage to the power-take-off drive transmission of the tractor is avoided. Free-wheel clutches which are sometimes referred to as over running clutches will be well known to those skilled in the art.

Drive is transmitted from the second drive shaft 40 to the output shaft 26 through an isolating clutch means 25 and a pair of drive elements, namely, a first drive element comprising a first sprocket 45 and a second drive element comprising a second sprocket 45. A drive chain 47 transmits drive from the first sprocket 45 to the second sprocket 46. The isolating clutch means is described below.

The sprocket 45 is co-axial with and rigidly mounted on the second drive shaft 40. The second sprocket 46 is co-axial with and rotatably mounted on the output shaft 26 by bearings 48 which are located spaced apart from each other in a bore 49 of the sprocket 46 by an annular shoulder 50 extending into the bore 49. Circlips 51 and 52 engage grooves 53 and 54, respectively, in the output shaft 26 and the bore 49, and co-operate with the bearings 48 for locating the second sprocket 46 on the output shaft 26 to avoid axial movement of the sprocket 46 on the output shaft 26.

The isolating clutch means comprises a clutch 55, one plate of which is formed by the second sprocket 46, and another plate of which is formed by a third drive element 57. The third drive element 57 comprises a circular clutch disc 58 and a stub shaft 59 axially extending from the clutch disc 58. A splined bore 60 extends through the clutch disc 58 and stub shaft 59 for engaging the splines 33 on the free end of the output shaft 26 for transmitting drive from the clutch disc 58 to the output shaft 26. The third drive element 57 is slidable axially on the output shaft 26 along the splines 32 from a disengaged position illustrated in Fig. 6 with the clutch disc 58 spaced apart and disengaged from the second sprocket 56 to an engaged position illustrated in Fig. 7 with the clutch disc 58 in driving engagement with the second sprocket 46 for transmitting drive from the second sprocket 46 to the output shaft 26. The second sprocket 46 is provided with a clutch plate face 61 co-operable with a corresponding face 62 on the clutch disc 58 for transmitting drive. A pair of dogs 63 project from the clutch plate face 61 of the sprocket 46 for engaging corresponding recesses 64 on the face 62 of the clutch disc 58 for the positive transmission of drive between the second sprocket 46 and the clutch disc 58.

The stub shaft 59 of the third drive element 57 is rotatable in a sleeve 65 which is retained on the stub shaft 59 by a circular flange 66 extending around the stub shaft 59. A pair of circular flanges 67 and 68 extend round the sleeve 65 and define an annular groove 69 for a purpose to be described below. A pair of tensioning springs 70 connected between the rear end member 7 of the chassis 3 and the flange 67 of the sleeve 65 urge the third drive element 57 into the disengaged position. Means for moving the third drive element between the disengaged and the engaged * position comprises a double acting hydraulic ram 71 and an operating lever 72. The operating lever 72 comprises a main arm 73 pivotally connected to the side member 5 of the main chassis 3 by a pivot pin 74 carried in brackets 75 on the side member 5. A pair of spaced apart tines 76 extending from the main arm are engagable in the annular groove 69 formed by the flanges 67 and 68 of the sleeve 65 for urging the sleeve 65 in the directions of the arrows A and B for engaging and disengaging the clutch 55. The hydraulic ram 71 comprises a housing 77 pivotally connected to the rear end member 7 by a pivot pin 78 carried on brackets 79 mounted on the rear end member 7. A piston rod 80 extends from the housing 77 and is pivotally connected to one of the tines 76 by a pivot pin 81 carried on brackets 82 on the tine 76. The ram is powered by an hydraulic power supply from the tractor through an hydraulic valve (not shown). The hydraulic valve (not shown) in the tractor cab is operable by a lever (not shown), and the lever and valve are so arranged that the lever must be operated by the driver to move the clutch from the disengaged to the engaged position, and the isolating clutch 55 is only in the engaged position while the lever is retained in the operating position by the operator.

In this embodiment of the invention a step down gear ratio of 7.51 is provided between the input shaft 25 and output shaft 26. The gear ratio between the sprockets 49 and 50 is a step down ratio of 1.5:1.

Referring now to Figs. 1 to 3, an outlet duct 90 extends downwardly from the container body 12 towards the front thereof and communicates with an extruder 91 for delivering peat in the container body 12 into the extruder 91. The extruder 91 comprises a cylindrical housing 92 having an auger screw (not shown) mounted therein for pressurising the peat. A secondary drive shaft 94 extending from the gear box 28 drives the auger screw (now shown) through a suitable drive transmission (also not shown). The extruder 91 delivers peat to an extruder head 95 having eight extrusion outlets 96 through which eight elongated extrusions of peat are delivered onto the surface of the bog. Means for forming transverse marks at predetermined longitudinal intervals in the extrusions to facilitate breaking of the extrusions into sods of turf when the extrusions are dry is provided but not shown. The extruder head 95 is pivotally connected to the cylindrical body 92 of the extruder 91 and may be raised or lowered to a desired position by an hydraulic ram 98. The hydraulic ram 98 is pivotally mounted on the container body 12 at 99, and is pivotally connected to a support arm 100 which is in turn pivotally mounted on the container body 12 at 101. A support chain 102 depending from the support arm 100 connects the extruder head 95 to the support arm 100. The ram 98 is also powered by the hydraulic power supply of the tractor, and hydraulic fluid is delivered to the hydraulic ram through a suitable valve which is controlled from the cab of the tractor.

In use, peat is loaded into the container body 12 and the container body 12 is hitched to a tractor or other suitable towing vehicle. The power-take-off shaft of the tractor is connected by a suitable drive shaft (not shown) to the input shaft 25. The hydraulic rams 77 and 98 are connected into the hydraulic system of the tractor for operating the isolating clutch 55 and for positioning the extruder head 95, respectively. The ram 77 is operated by the operating lever (not shown) provided in the driving cab of the tractor.

When the container body 12 has been loaded the trailer 1 is towed by the tractor over the surface of the bog. To commence towing, the clutch of the tractor and isolating clutch 55 of the trailer 1 are engaged substantially simultaneously. The tractor and trailer 1 thus drive forwardly, and by virtue of the fact that the front wheels 15 of the trailer 1 are driven, the towing load on the tractor is significantly reduced thereby preventing the rear wheels of the tractor sinking in the bog and becoming stuck. Should the power-take-off shaft of the tractor drive the trailer 1 faster than the tractor is moving, the driver on feeling the push from the trailer 1 can release the lever (not shown) in the cab for putting the isolating clutch 55 into the disengaged position. On the other hand, should the tractor tow the trailer 1 faster than it is being driven by the power-take-off shaft, the free-wheel clutch 43 prevents transmission of drive from the front drive wheels 15 to the output shaft 25, thereby preventing any danger of damage to the powertake-off drive mechanism of the tractor.

As the trailer 1 is being towed by the tractor the extrusion head 95 is lowered to the desired level by the ram 98, and the extruder 91 is activated thereby extruding elongated extrusions of peat which are laid out on the bog.

While the free-wheel clutch means has been described as being a free-wheel clutch, any other suitable freewheel clutch means may be used.

While the drive transmission means has been described as comprising an isolating clutch in certain cases the isolating clutch may be omitted. Needless to say while a particular construction of isolating clutch has been described any other suitable isolating clutch means may be provided.

It will of course be appreciated that any other drive transmission means may be provided.

While the trailer has been described as comprising an extruder for extruding peat, this is not necessary.

The trailer may only comprise a container body if desired. Indeed, in other cases, it is envisaged the trailer may not comprise a container body at all, rather, it may comprise only a chassis or a flat bed. For example, should it be desired to use the trailer for withdrawing felled timber from a forest, it is envisaged that the trailer may only comprise a flat bed or in certain cases only a chassis onto which the felled timber would be stacked and secured.

While the trailer has been described as comprising front and rear wheels, with tracks extending around the front and rear wheels, it is envisaged in certain cases that the trailer may be provided with an intermediate wheel, or indeed, intermediate wheels between the front and rear wheels to provide greater support for the track intermediate the front and rear wheels. Additionally, it will be appreciated that the tracks may be dispensed with, in which case, suitable ground engaging wheels would be used which would not sink into the soft terrain. Typically, tractor wheels may be used.

It is also envisaged that the rear axle may be adjustably mounted to the chassis so as to be movable rearwardly relative to the chassis for tightening the tracks .

The invention is not limited to the embodiment hereinbefore described which may be varied in construction and detail.

Claims (5)

1. A trailer comprising a chassis, at least two ·> ground engaging wheels rotatably mounted on the chassis, hitch means extending from the chassis for hitching the trailer to a towing vehicle, and drive transmission means for transmitting drive from a power-take-off shaft of the towing vehicle for driving at least one of the ground engaging wheels, the drive transmission means comprising an input means for connection to the power-take-off shaft of the towing vehicle and an output means operably connected to the at least one ground engaging wheel, a free-wheel clutch means provided in the drive transmission means between the input means and the output means for permitting drive in one rotational direction to be transmitted from the input means to the output means, and for preventing drive in that one rotational direction being transmitted from the output means to the input means .

2. A trailer as claimed in Claim 1 in which an isolating clutch means is provided in the drive transmission means for isolating the input means from the output means.

3. A trailer as claimed in Claim 1 or 2 in which the drive transmission means comprises a first drive shaft driving a second drive shaft through the free-wheel clutch means, two of the ground engaging wheels being driven through a differential drive unit, the output means comprising an output drive shaft connected to 5 the differential drive unit for driving the differential drive unit, the output drive shaft receiving drive from the second drive shaft through first and second drive elements, the first drive element being rigidly mounted on and co-axial with the 10 second drive shaft and being operably connected therewith, the second drive element being mounted on and being co-axial with the output drive shaft and freely rotatable relative to the output drive shaft, the isolating clutch means comprising a third drive 15 element for transmitting drive from the second drive element to the output drive shaft, the third drive element being mounted on and co-axial with the output drive shaft, and being slidable axially on the output drive shaft from a disengaged position disengaged from 20 the second drive element isolating drive to the output drive shaft to an engaged position engaging the second drive element with drive being transmitted through the isolating clutch means to the output shaft, and means for moving the third drive element between the 25 disengaged and the engaged positions being provided.

4. A trailer as claimed in any preceding claim in which the trailer comprising a container body carried on the chassis, and an extruder extending from the container body and communicating therewith for extruding material from the container body, and a 5 front pair and a rear pair of ground engaging wheels being provided, the front pair of ground engaging wheels being driven by the transmission means, and a pair of ground engaging tracks extending around respective front and rear ground engaging wheels on 10 opposite sides of the chassis.

5. A trailer substantially as described herein with reference to and as illustrated in the accompanying drawings . Dated this 23rd day of April 1993 F.F. BYs EXECUTIVE Agents for the Applicants, Clifton House, Lower Fitzwilliam Street, Dublin 2. ί