GB1568211A - Vehicle provided with a raising and lowering mast assembly - Google Patents

Description

(54) A VEHICLE PROVIDED Wilil A RAISING AND LOWERING MAST ASSEMBLY (71) We, WARD PLANT SPARES (HEN LEY) LIMITED, of 8 Gawne Lane, Cradley Heath, Warley, West Midlands B64 SQY, a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a vehicle provided with a raising and lowering mast assembly. In particular, the invention is concerned with such a vehicle (for example a fork lift truck for handling palletised loads or a rough terrain vehicle intended for mechanical handling applications on building sites, farms and the like) in which the mast assembly includes a carriage which has a tipping facility.

According to the present invention we provide a vehicle provided with a rising and lowering mast assembly and one or more implements for carrying loads, said assembly comprising a number of mast sections each comprising a pair of spaced uprights, a first one of said mast sections being mounted directly on the vehicle and the remaining mast section(s) being mounted on the vehicle through the agency of said first mast section, a carriage structure mounted an a second one of said mast sections for vertical adjustment relative thereto, said carriage structure comprising a main frame which is slidably engaged with the uprights of the second section and a sub-frame pivotal relative to said main frame between generally horizontal and vertical dispositions about a generally horizontal axis extending transversely of said mast assembly and located adjacent the lower ends of the main frame and the sub-frame, means for effecting vertical adjustment of said mast sections and the carriage relative to one another and a pair of fluid-powered rams mounted on the carriage structure for effecting pivoting of said subframe relative to the main frame of the carriage structure, said sub-frame including adjacent its upper end a transverse portion extending parallel to said horizontal axis and the or each implement being provided with hook means adapted for engagement with said transverse portion whereby the or any one of the implements can be releasably mounted on the sub-frame for tilting movement therewith.

In one embodiment of the invention, said second section is mounted on the first section via a second carriage which is mounted for vertical adjustment on said first section. Thus, the second section may be releasably attachable to the second carriage and constitute an auxiliary mast structure.

In the preferred embodiment of the invention there are three mast sections, the second section being mounted slidably on the third section which, in turn, is mounted slidably on the first section, said means for effecting adjustment being operable to adjust all three sections simultaneously relative to one another; said adjusting means includes a pair of hydraulic rams extending one alongside each of the uprights of the first section and arranged to act between the first and third sections and chain and pulley means for translating adjustment of said third section relative to the first section into adjustment of the second section relative to the third section; said adjusting means further includes a hydraulic ram having one end connected to said second section and provided with pulley means at the other end thereof, and chains entrained over the pulleys and anchored at their opposite ends to the carriage main frame and said second sections; and the main frame of the carriage is provided with rollers and the uprights of said second section are of channel-section, the rollers being received within said channel-section uprights.

It is to be noted that the carriage structure can be used to provide a tipping facility when used in conjunction with said impler ment or one of said implements and that the main frame thereof is mounted directly on the mast rather than through the agency of an intermediate carriage thereby keeping the load centre closer to the mast structure.

Because said adjusting means comprises a pair of rams located one alongside each side of said first mast section, the rams do not encroach upon the space between the uprights of the first mast section. Thus, with this arrangement, when the mast sections are fully extended with respect to one another, the vehicle driver is afforded a clear view through the space between the upright of the first section.

The invention will now be described by way of example with reference to the accompanying drawings, in which: - Figure 1 is a fragmentary side elevation of an accessory mast and tipping sub-frame, showing one possible implement mounted thereon and in two alternative positions, and also showing somewhat diagrammatically the outline of a portion of the lift truck to which the accessory mast is attached; Figure 2 is a plan view of the accessory mast; Figure 3 is a front elevation of the same showing the part in two alternative positions; Figure 4 is a side view of another embodiment of the invention, the mechanism being shown attached to the front of the wheeled vehicle and its fully retracted condition; Figure 5 is a front view of the mechanism; Figure 6 is a plan view of the mechanism;; Figure 7 is a side view of the mechanism showing the same in its fully extended position; and Figure 8 is a front view of the mechanism when in its fully extended position.

Referring firstly to Figures 1 to 3, the front wheels of the lift truck are indicated by the reference numeral 10, the mast of the lift truck by the reference 12 and the carriage of the lift truck by the reference 14, the carriage being movable along the mast. The accessory mast comprises channel section side members 16 provided with brackets 18 for attachment to the carriage. The accessory carriage comprises a main frame which comprises pairs of plates 20, see Figures 2 and 3, carrying rollers engaged in the side members for slidably guiding the carriage in its movement within the accessory mast. The accessory carriage is provided with laterally projecting brackets 22 and the accessory mast is provided with further brackets 24 which are aligned with the brackets 22, see especially Figure 2. The accessory carriage is movable independently of the carriage 14.

Each side of the accessory mast supports a ram 26 and the piston rod of the same carries a clevis 28 journalling a pulley 30.

A flexible transmissing chain, cable or the like 32 has one end attached to the bracket 24 and the other end to the bracket 22 and passes around the pulley 30. Extension of the rams from the full line position (Figure 3) to the chain dot line position lifts the pulleys and elevates the carriage, the stroke of the carriage being double the stroke of the ram by virtue of the described arrangement.

Each pair of plates 20 fulcrums a subframe comprising a further pair of plates 34, the fulcrum axis being indicated by reference 36. A tipping ram is provided between each pair of plates 20 and is connected to the sub-frame 34 at axis 38, the opposite end of each tipping ram being pivoted to the plates on axis 40 so that the rams lie within the confines of the main frame and the mast 16. Contraction of the rams (not shown in the drawings) from the substantially vertical position which they would occupy in Figure 1, draws the axis 38 towards the axis 40 and displaces the subframe 34 from the position shown in full line in the lower portion of Figure 1 to the second of the two chain dot line positions shown at the upper portion of Figure 1.

The tipping rams are connected together for simultaneous operation and the two sub-frames 34 are connected, for example by means of transverse shafts on axes 44, 46 and these shafts are also used to couple the accessory implement which is intended to be lifted, lowered, tipped and returned from the tipped position. As shown in Figures 1 to 3, the implement is a grain bucket which is provided with inverted jawlike brackets 48 to engage shaft 44 and with apertured lugs 50 engaged by shaft 46. It will be appreciated that alternative implements can be attached.

Referring next to Figures 4 to 8, a rough terrain vehicle (the front wheels 110 only which are shown) is provided with a load handling mechanism comprising an outer mast section 112, an intermediate section 114 and a carriage supporting section 116.

Each section comprises a frame having parallel spaced channel section side members 112a, 114a, 116a arranged in nested relation and for extension longitudinally with respect to one another, the side members being connected together by crossmembers 112b, I14b and 116b. The lower end of the mast section 112 is connected pivotally to - unshown means to the vehicle and one or more unshown fluid powered rams are provided to enable the attitude of the mast section 112 to be adjusted with respect to- the vertical.

The top of the section 114 projects above the mast section 112 when the sections are retracted and has rearwardly extending plates 120 for rotatably supporting respective sprockets 122 with their axes extending foreand-aft. A chain or other flexible drive transmission member 124 is entrained over each sprocket 122 and is coupled at its free ends to the mast section 112 and the section 116 adjacent their respective lower ends. A pair of vertically extending, single acting fluid powered rams 128 are provided one on each side section 112 and act between the lower ends of the section 112 and the upper ends of the section 114, extension of the rams 128 in unison being effective to raise the section 114 upwardly.

At the same time, the raising motion of the section 114 is transmitted to the section 116 via the chain and sprocket drive and this arrangement may be such that the section 116 is raised to a distance of, for example, twice the stroke of the rams 128.

A carriage 130 is provided on the section 116 and is mounted for lengthwise sliding movement relative thereto. The carriage 130 includes a pair of accessory mounting arms 132 for mounting a bucket or the like in the manner disclosed above in connection with Figures 1 to 3 and, if desired, the carriage may be adapted for "side shift ' motion relative to the mast as disclosed in co-pending British Patent Application Nos.

2243/76, 2772/76 and 42875/76 (Serial No.

1,542,871). A pair of chains 134 are each coupled at its ends to the carriage 130 and the intermediate cross-member 11 6b and each chain is entrained over a respective sprocket 136 carried at the upper end of the piston rod of a single acting, fluid powered ram 138 mounted on the section 116. Thus, as the ram 138 is extended, the carriage 130 is raised through a distance greater than the stroke of the ram 138, which distance will depend on the mechanical advantage afforded by the chain and sprocket transmission.

A feature of this embodiment of the invention is that raising of the carriage is effected in two stages by independent rams.

Hitherto so far as we are aware, raising of carriage in a three section mast has been effected by a compound telescopic ram located centrally of the mast assembly.

Thus, the complexity, costs and maintenance problems that are entailed with such compound rams are avoided. Another feature of this embodiment is that the rams acting between the section 112 and 114 do not encroach upon the space between the side members 112a, thereby affording the vehicle driver a clear view in the forward direction when the sections are extended.

Furthermore, with the arrangement described, dual loading is easier to introduce.

For example, if the cylinders of the rams 128 and 138 are of the same bore, for a given pressure the carriage will lift the weight of amount A on operation of the ram 128 and only a weight of A/2 upon operation of the rams 138 (neglecting frictional differences). Thus, for large loads, excess heights can be avoided which would otherwise result in machine instability.

Another feature is that the rams 138 can be operated independently if the rams 128, thus allowing the mechanism to be used in buildings of low heights by raising only the carriage supporting sections. Although the rams 128 and 138 are described as being single acting, double acting rams may be employed if desired.

WHAT WE CLAIM IS: - 1. A vehicle provided with a raising and lowering mast assembly and one or more implements for carrying loads, said assembly comprising a number of mast sections each comprising a pair of spaced uprights, a first one of said mast sections being mounted directly on the vehicle and the remaining mast section(s) being mounted on the vehicle through the agency of said first mast section, a carriage structure mounted on a second one of said mast section for vertical adjustment relative thereto, said carriage structure comprising a main frame which is slidably engaged with the uprights of the second section and a sub-frame pivotal relative to said main frame between generally horizontal and vertical dispositions about a generally horizontal axis extending transversely of said mast assembly and located adjacent the lower ends of the main frame and the subframe, means for effecting vertical adjustment of said mast sections and the carriage relative to one another and a pair of fluidpowered rams mounted on the carriage structure for effecting pivoting of said subframe relative to the main frame of the carriage structure, said sub-frame including adjacent its upper end a transverse portion extending parallel to said horizontal axis and the or each implement being provided with hook means adapted for engagement with said transverse portion whereby the or any one of the implements can be releasably mounted on the subframe for tilting movement therewith.

2. A vehicle as claimed in Claim 1 in which said fluid powered rams are located within the space between the uprights of said second section.

3. A vehicle as claimed in Claim 1 or 2 in which said sub-frame includes a pair of lever arms each pivotal at its lower end about said generally horizontal axis and joined together by said transverse portion and in which said fluid powered rams each extend generally vertically between an upper pivotal anchorage on the main frame

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (12)

**WARNING** start of CLMS field may overlap end of DESC **. retracted and has rearwardly extending plates 120 for rotatably supporting respective sprockets 122 with their axes extending foreand-aft. A chain or other flexible drive transmission member 124 is entrained over each sprocket 122 and is coupled at its free ends to the mast section 112 and the section 116 adjacent their respective lower ends. A pair of vertically extending, single acting fluid powered rams 128 are provided one on each side section 112 and act between the lower ends of the section 112 and the upper ends of the section 114, extension of the rams 128 in unison being effective to raise the section 114 upwardly. At the same time, the raising motion of the section 114 is transmitted to the section 116 via the chain and sprocket drive and this arrangement may be such that the section 116 is raised to a distance of, for example, twice the stroke of the rams 128. A carriage 130 is provided on the section 116 and is mounted for lengthwise sliding movement relative thereto. The carriage 130 includes a pair of accessory mounting arms 132 for mounting a bucket or the like in the manner disclosed above in connection with Figures 1 to 3 and, if desired, the carriage may be adapted for "side shift ' motion relative to the mast as disclosed in co-pending British Patent Application Nos. 2243/76, 2772/76 and 42875/76 (Serial No.

1,542,871). A pair of chains 134 are each coupled at its ends to the carriage 130 and the intermediate cross-member 11 6b and each chain is entrained over a respective sprocket 136 carried at the upper end of the piston rod of a single acting, fluid powered ram 138 mounted on the section 116. Thus, as the ram 138 is extended, the carriage 130 is raised through a distance greater than the stroke of the ram 138, which distance will depend on the mechanical advantage afforded by the chain and sprocket transmission.

A feature of this embodiment of the invention is that raising of the carriage is effected in two stages by independent rams.

Hitherto so far as we are aware, raising of carriage in a three section mast has been effected by a compound telescopic ram located centrally of the mast assembly.

Thus, the complexity, costs and maintenance problems that are entailed with such compound rams are avoided. Another feature of this embodiment is that the rams acting between the section 112 and 114 do not encroach upon the space between the side members 112a, thereby affording the vehicle driver a clear view in the forward direction when the sections are extended.

Furthermore, with the arrangement described, dual loading is easier to introduce.

For example, if the cylinders of the rams 128 and 138 are of the same bore, for a given pressure the carriage will lift the weight of amount A on operation of the ram 128 and only a weight of A/2 upon operation of the rams 138 (neglecting frictional differences). Thus, for large loads, excess heights can be avoided which would otherwise result in machine instability.

Another feature is that the rams 138 can be operated independently if the rams 128, thus allowing the mechanism to be used in buildings of low heights by raising only the carriage supporting sections. Although the rams 128 and 138 are described as being single acting, double acting rams may be employed if desired.

WHAT WE CLAIM IS: - 1. A vehicle provided with a raising and lowering mast assembly and one or more implements for carrying loads, said assembly comprising a number of mast sections each comprising a pair of spaced uprights, a first one of said mast sections being mounted directly on the vehicle and the remaining mast section(s) being mounted on the vehicle through the agency of said first mast section, a carriage structure mounted on a second one of said mast section for vertical adjustment relative thereto, said carriage structure comprising a main frame which is slidably engaged with the uprights of the second section and a sub-frame pivotal relative to said main frame between generally horizontal and vertical dispositions about a generally horizontal axis extending transversely of said mast assembly and located adjacent the lower ends of the main frame and the subframe, means for effecting vertical adjustment of said mast sections and the carriage relative to one another and a pair of fluidpowered rams mounted on the carriage structure for effecting pivoting of said subframe relative to the main frame of the carriage structure, said sub-frame including adjacent its upper end a transverse portion extending parallel to said horizontal axis and the or each implement being provided with hook means adapted for engagement with said transverse portion whereby the or any one of the implements can be releasably mounted on the subframe for tilting movement therewith.

2. A vehicle as claimed in Claim 1 in which said fluid powered rams are located within the space between the uprights of said second section.

3. A vehicle as claimed in Claim 1 or 2 in which said sub-frame includes a pair of lever arms each pivotal at its lower end about said generally horizontal axis and joined together by said transverse portion and in which said fluid powered rams each extend generally vertically between an upper pivotal anchorage on the main frame

and a lower pivotal anchorage on a respective one of said lever arms which is located rearwardly of said generally horizontal axis when the sub-frame is generally vertical, the arrangement being such that extension of said fluid powercd rams effects tilting of the sub-frame towards said generally vertical disposition and retraction of said fluid powered rams effecting tilting of the sub-frame towards said generally horizontal disposition.

4. A vehicle as claimed in any one of Claims 1-3 in which the or each implement is provided with apertured lugs below said hook means and the sub-frame is provided with shaft means for engagement in the apertures of said lugs when the implement is mounted on the sub-frame with its hook means engaged over said transverse portion.

5. A vehicle as claimed in any one of Claims 14 in which there are three mast sections, the second section being mounted slidably on the third section which, in turn, is mounted slidably on the first section, said means for effecting adjustment being operable to adjust all three sections simultaneously relative to one another.

6. A vehicle as claimed in Claim 5 in which said adjusting means includes a pair of hydraulic rams extending one alongside each of the uprights of the first section and arranged to act between the first and third sections and chain and pulley means for translating adjustment of said third section relative to the first section into adjustment of the second section relative to the third section.

7. A vehicle as claimed in Claim 6 in which the pulleys are mounted on said third section and in which the chains are each entrained over the pulleys with its ends anchored to the second and first sections.

8. A vehicle as claimed in Claim 5, 6 or 7 in which said adjusting means further includes a hydraulic ram having one end connected to said second section and provided with pulley means at the other end thereof, and chains entrained over the pulleys and anchored at their opposite ends to the carriage main frame and said second sections.

9. A vehicle as claimed in any one of the preceding claims in which the main frame of the carriage is provided with rollers and the uprights of said second section are of channel-section, the rollers being received within said channel-section uprights.

10. A vehicle as claimed in Claim 1 in which said second section is mounted on the first section via a second carriage which is mounted for vertical adjustment on said first section.

11. A vehicle as claimed in any one of Claims 1-10 in which the lower end of said first section is pivoted to the vehicle and one or more hydraulic rams is provided to enable the attitude thereof to be adjusted relative to the vertical.

12. A vehicle provided with a mast asassembly substantially as hereinbefore described with reference to, and as shown in, Figures 1-3 or Figures 48 of the accompanying drawings.