Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B66—HOISTING; LIFTING; HAULING
  • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
  • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
  • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
  • B66F9/075—Constructional features or details
  • B66F9/08—Masts; Guides; Chains
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B66—HOISTING; LIFTING; HAULING
  • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
  • B66F3/00—Devices, e.g. jacks, adapted for uninterrupted lifting of loads
  • B66F3/02—Devices, e.g. jacks, adapted for uninterrupted lifting of loads with racks actuated by pinions
  • B66F3/06—Devices, e.g. jacks, adapted for uninterrupted lifting of loads with racks actuated by pinions with racks comprising pivotable toothed sections or segments, e.g. arranged in pairs

Definitions

• the present invention relates to a forklift truck hav ⁇ ing a wheeled chassis, a lifting mast and a lifting fork carried by said mast.
• the forward vision of the truck driver is an aspect of safe working which must be given the greatest of attention.
• the thickness of the vertical guides must not be of such a nature as to unduly obstruct the vision of the driver.
• attempts have been made to slenderize the said vertical guides , in order to provide the truck driver with the clearest possible forward view.
• the provision of slender guides has improved the forward view of such fork ⁇ lift trucks to some extent, it has resulted in an unfavour ⁇ able wheel-pressure distribution.
• one object of this invention is to pro ⁇ vide a forklift truck of the said kind in which the afore- mentioned disadvantages are substantially eliminated in a simple and economic manner.
• a forklift truck having a wheeled chassis, a lifting mast, and a load-carrying fork arrangement carried by said mast, characterized in that said mast is arranged for movement between a first position in which at least a major part of the mast is located sub ⁇ stantially horizontally beneath said chassis, and a second position in which at least a major part of said mast extends rigidly vertically.
• the mast comprises a plurality of indi ⁇ vidual, elongate sections which are pivotally connected to ⁇ gether in a manner such that when the sections form a straight line said sections are able to pivot in only one direction; and in that a means is provided for preventing pivotal movement of said sections in said one direction when the mast is raised, thereby to form a column which is rigid in all directions.
• the sections are preferably of substantially U-shaped cross-section, exhibiting a web portion and two leg por- tions extending at right angles from a respective end of said web portion; and mounted on the free ends of each of said leg portions are pairs of mutually spaced apart lugs, the spaces between said lugs being effective to receive a respective portion of an adjacent section, such as to lock said section against pivotal movement in three directions.
• the means for preventing pivotal movement of said sections in said one direction comprises a plunger mechanism carried by individual sections and arranged to engage an opening located in an adjacent section.
• the plunger mechanism pre ⁇ ferably includes a plunger having at least one wheel or roller which is guided in a curved guide means extending from a vertical position in front of the truck to a hori ⁇ zontal position beneath said truck.
• the arrangement of' the guide means is such that respective plungers are moved axially, into and out of the openings of respective adja- cent sections, as the mast is raised and lowered respec ⁇ tively.
• Movement of the mast sections between said first and said second positions is effected through rollers mounted on respective mast sections and arranged to run in the guide means, said guide means extending in a curved manner from a substantially vertical position in front of the truck to a substantially horizontal position beneath the chassis thereof. It will be understood that the extent of the guide means in its vertical direction is such as not to obstruct the forward view of the driver.
• FIG. 1 illustrates in side view a forklift truck according to the invention with its mast in a raised posi ⁇ tion
• Fig. 2 is a view similar to Fig. 1 with the mast in a lowered position, in which a greater part of the mast is located beneath the truck,
• Fig. 3 is* an end view of a mast section seen on the line III-III in Fig. 6,
• Fig. 4 is a side view of the mast section illustrated in Fig. 3
• Fig- 5 is a sectional view taken on the line V-V in
• Fig. 6 illustrates a section seen on the line VII-VII in Fig. 5 and discloses the manner in which mutually adjacent mast sections are interconnected, and
• Fig. 7 illustrates the action of the plunger mecha ⁇ nisms as the mast is raised and lowered.
• a forklift truck generally referenced 1 having a chassis 2, wheels 3, a lifting mast, generally shown at 4, and lifting forks 5.
• the mast 4 comprises a plurality of interconnected, pivotable sections 6 arranged for movement from a first position in which at least a major part of the mast is located substantially horizon ⁇ tally beneath the chassis 2 (Fig. 2), to a second position in which at least a major part of the mast is located substantially vertically in front of the truck (Fig. 1).
• the sections are also arranged for movement between positions intermediate of said first and second positions. The extent to which the mast is moved between these positions will, of course, depend on the ceiling height of the locale in which the truck is to work or the height to which goods to be transported are stacked.
• the sections 6 are pivotable relative to one another in a plane such that in one direction they can be swung to form a straight mast, while in another direction they can swing in a manner to permit them to be guided along a curved guide path, from beneath the chassis 2 to a vertical position in front of the truck, in a manner hereinafter described.
• the mast sections 6 are pivotally connected by lugs 7.
• lugs 7 These lugs -are mounted on each end of a respective section, so as to be located at the four corners thereof as shown in Fig. 3.
• the lugs 7 comprise pairs of spaced apart plates (not referenced). It will be understood from this that, when the mast is being raised, the lugs 7 are pivoted to a straight line, i.e.
• each section 6 of the mast illu- strated in Figs. 3,4,5 and 7 is provided at one end there ⁇ of with a locking means generally shown at 9.
• the locking means 9 comprises a plunger 10 which extends from a shaft 11 at right angles thereto.
• a roller 12 mounted for rotation on each end of the shaft 11 is a roller 12 which is guided for movement in a guide 13. It should be mentioned here that although the illustrated embodiment prefers the provision of two rollers 12, as shown, only one roller need be pro- vided j with the plunger 10 located in the vicinity of said roller.
• the guide 13 of the illustrated embodiment is formed integrally with a further guide 14 which extends in a curved path from a vertical position in front of the truck 1 to a horizontal position beneath the chassis 2. * As before mentioned, the height to which the guide 14 ex ⁇ tends in front of the truck 1 should not be such as to obstruct the forward view of the driver.
• rollers 15 Arranged for rotation in the guides 14 are rollers 15 mounted on shafts 16 extending through respective lugs 7.
• the plunger 10 of the locking means extends through a casing 17 having an end wall 18 and an intermediate wall 19, and is biassed by a spring 20 arranged between the walls 18 and 19.
• the plunger 10 is intended to engage an opening 21 arranged in or on a respective section 6, at the end thereof opposite the locking means 9, as shown in Fig. 3.
• the arrangement of the guide means 14 is such that as the sections 2 are moved around the curve of said guide means to take a vertical position, the plungers 10 are progressively displaced axially by the guide means 14 until said plungers enter their respective openings 21 of adjacent sections 6, the springs 20 serving to assist in holding the plungers in said openings.
• the plungers are con- veniently tapered at the ends thereof adjacent the open ⁇ ings, and said openings suitably have a conforming inter ⁇ nal shape.
• the mast elements 6 of the illustrated embodiment are provided along one side thereof with teeth 22, as are also the lugs 7.
• the teeth 22 are arranged to mesh with the toothed drive wheel 23, for raising and lowering the mast 4.
• the mast 4 is lowered until the upper ⁇ most section 26, i.e. the section carrying the forks 5, is located at the top of the guide 14, such that the drive wheel 23 is constantly in driving engagement with the teeth 22 of a mast section 6.
• the wheel 23 is rotated by means (not shown), so as to move the sections from their horizontal position to a vertical one.
• the lugs 7 pivot to their maximum angle of pivot, i.e. to an angle of 180 , and the contacting surfaces 8 at the leading edge are acted upon by compression forces, and the sections are locked against pivotal movement in three directions.
• the plungers 7 are displaced axially until they enter respective openings 21, thereby locking the sections 6 against pivotal movement in the fourth direction, i.e. against movement resulting from a force acting in the direction of arrow P in Fig. 1.
• the* guide means 14 may be arranged to extend up behind the truck 1, thereby enabling a longer mast to be provided.
• the described and illustrated forklift truck offers many advantages over those trucks at present known to the art. For example, not only does the driver have a completely free view when manouvering his vehicle to pick up a load, but can also, work efficiently in locales of greatly differing ceiling heights with one and the same truck. An example of this is the removal of goods from inside a container to a large warehouse.
• any pivotal movement of the sections 6 when subjected to a force acting in the direction of arrow P of Fig. 1 may be prevented or the force counteracted by means of a line or chain 24 wound on a drum 25 and extend ⁇ ing along the pressured side of the mast parallel thereto, said line or chain being held in tension by means not shown, such as a spring.
• the line or chain may be used instead of the locking means 9 or may be used in con- junction therewith as an additional safety factor.
• two or more masts may be arranged side by side, and the sections 6 may be connected together by means other than those illustrated, e.g. by links or latches. Also, the curved part of the mast may be guided along different paths or rolled up.

Landscapes

• Engineering & Computer Science (AREA)
• Structural Engineering (AREA)
• Transportation (AREA)
• Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• Mechanical Engineering (AREA)
• Civil Engineering (AREA)
• Forklifts And Lifting Vehicles (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20338684

Family Applications (1)

Country Status (5)

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Family Cites Families (1)

• 1979
  • 1979-08-24 SE SE7907073A patent/SE420402B/sv unknown
• 1980
  • 1980-07-25 JP JP50179180A patent/JPS56501281A/ja active Pending
  • 1980-07-25 WO PCT/SE1980/000194 patent/WO1981000559A1/en not_active Ceased
  • 1980-08-21 IT IT24241/80A patent/IT1132448B/it active
• 1981
  • 1981-03-09 EP EP80901467A patent/EP0034152A1/en not_active Ceased

Non-Patent Citations (1)

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