GB1573098A

GB1573098A - Fork lift safety devices

Info

Publication number: GB1573098A
Application number: GB5110475A
Authority: GB
Original assignee: Leonard & Co Ltd E V
Current assignee: Leonard & Co Ltd E V
Priority date: 1976-12-08
Filing date: 1976-12-08
Publication date: 1980-08-13

Description

(54) FORK-LIFT SAFETY DEVICES (71) We, E.V. LEONARD & CO.

(HANDLING DEVICES) LIM1TED, a British Company, of Nutsford Works, Pink Bank Lane, Manchester M12 5GH, 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 concerns fork-lift safety devices and has as its objective the provision of a safety device that may be applied to various items of materials handling or other equipment such as pallets, hoppers, skips and so on (all herein called, for convenience, "fork-liftable equipment") intended to be lifted by lifting forks on, e.g., a fork-lift truck, the safety device operating automatically to prevent detachment of the equipment from such lifting forks when supported thereby but not impeding attachment and detachment when not fork-supported.

A safety device in accordance with the present invention comprises a latch adapted to be pivotally carried by an item of fork-liftable equipment so as to be pivotable between a release position in which the fork-liftable equipment can be engaged and disengaged by lifting forks and a fork-latching position for latching the fork-liftable equipment to lifting forks when supported thereby, and a pendulous ground-engaging member connected to said latch and adapted to apply torque thereto, when unsupported, to rock said latch into its said fork-latching position but to be displaceable by ground engagement to permit movement of said latch to its said release position in response to placing of the said fork-liftable equipment on a supporting surface.

Thus, a pallet or other fork-liftable item of equipment fitted with the safety device of the invention may, when supported by the ground or other surface, be engaged by and disengaged from the lifting forks of, for instance, a forklift truck by the usual manoeuvring of such forks without impediment by the safety device that automatically adopts a non-operative condition, with the latch in its release position, when the fork-liftable item is so supported.

However, upon lifting of such fork-liftable item clear of a supporting surface the pendulous ground-engaging member of the safety device becomes unsupported and automatically moves the latch into its fork-latching position so as to prevent detachment of the fork-liftable item from the said lifting forks when supporting it. The device thus ensures that there is no possibility of an item of fork-liftable equipment to which it is fitted accidentally becoming detached from supporting lifting forks, e.g. as a result of violent manoeuvring or the traversing of sloping or uneven ground.

The safety device of the invention may be applied to fork-liftable equipment having tunnels or like guides that receive lifting forks in a manner that precludes significant relative displacement other than in the direction of the length of the lifting forks: when the device is fitted to such an item it may then take a very simple form because in its fork-latching position the latch is required only to restrain move ment of a lifting fork relatively to its tunnel or like guide in one direction and sense. However, the device may also be fitted to forkliftable equipment having an open base frame.

In such a case, easier access is provided for lifting forks and lateral control of the base frame is required. However, this may be provid ed by appropriate dimensioning of the base frame and safety device in relation to the lifting forks.

Conveniently the latch and the groundengaging member are constituted by a pair of arms united at an angle at a pivot point in the manner of a bell-crank level.

The ground-engaging member of a safety device in accordance with the invention may be formed for ground engagement in any suit able way: for instance the member may terminate in a pad or foot and be so arranged in conjunction with like pads or feet to provide support for the fork-liftable item. Moreover, the ground-engaging member could terminate in a wheel, e.g. a castor wheel, that in conjunction with like wheels on an item of fork liftable equipment would provide mobility for such item of equipment fitted with the safety device.

Individual safety devices in accordance with the invention may be fitted to an item of forkliftable equipment for co-operation respectively with each of the lifting forks by which that item is to be lifted. Alternatively a single device may be constructed and fitted for cooperation with both such lifting forks.

The invention also extends to items of forkliftable equipment fitted with a safety device of the above-defined construction.

The invention will be further described by way of example with reference to the accompanying drawings in which: Figure 1 is a perspective view of a base frame having fork tunnels and fitted with a safety device in accordance with the present invention; Figure 2 is a perspective view of an open carrying frame fitted with a safety device in accordance with the present invention; Figure 3 is a side elevation of an open base frame carrying a tipping hopper and fitted with a safety device in accordance with the present invention; Figure 4 is a rear elevation of the arrangement of Figure 3; Figure 5 is a plan view of the base frame of Figure 3;; Figure 6 is a rear elevation of half of a base frame similar to that shown in Figures 3, 4 and 5, and having fork tunnels, and fitted with a safety device in accordance with the present invention, the operating catch for the hopper being omitted for clarity; and Figure 7 is a plan view of the arrangement of Figure 6.

The arrangement shown in Figure 1 comprises a base frame 1 for a hopper or other item of materials handling equipment and having fork-receiving tunnels 2 and 3. The base frame 1 is provided with a safety device in accordance with the present invention generally designated 4 comprising two bell-crank like elements 5 and 6 each having a pair of arms extending at an angle to one another. Each element 5 and 6 has, at the junction of its arm, a laterally and inwardly projecting stub axle 7 and 8 that rests upon and may roll on the upper surface of an associated fork tunnel. The elements 5 and 6 are disposed adjacent to the remote side surfaces of fork tunnels 2 and 3, respectively, and are linked together by a latch bar 9 and a ground-engaging angle member 10 that extend between corresponding extremities of their respective arms.

The safety device 4 is so constructed that when the base frame 1 is supported on a substantially flat surface, the device 4 adopts a release position, as shown in Figure 1, in which the angle member 10 engages the supporting surface and the bar 9 is so disposed below the fork tunnels as not to impede access thereto by lifting forks. Upon lifting of the base frame 1 by lifting forks, the device 4 pivots to a forklatching position, the bar 9 rising to engage behind the rear surface of the lifting forks so as to restrict relative displacement of the base frame 1 and lifting forks in the direction of the length of the lifting forks, and prevent detachment of the base frame 1 from the lifting forks.

Figure 2 shows an open carrying frame 11 having a safety device 12 pivotally mounted thereon. The safety device 12 comprises a pair of bell-crank like elements 13 and 14 each having a pair of arms extending at an angle to one another, the corresponding extremities of their respective arms being linked by latch bar 15 and ground-engaging bar 16 so that the elements 13 and 14 are spaced apart by a distance slightly exceeding the overall span of the lifting forks that are to be engaged thereby. The safety device 12 operates in an identical manner to the safety device 4 of Figure 1.

Figures 3, 4 and 5 show an open base frame 17 comprising two longitudinal carrier members 18 and 19 of L,shaped cross-section, linked by cross members 20 and 21 at corresponding ends thereof and one or more intermediate cross members 22. A lower cross member 23 disposed vertically below cross member 21 also spans the base frame 17, and together with this cross member defines in part an opening for receiving lifting forks, the base frame being supportable thereby on cross members 21 and 22. The base frame 17 carries a tipping hopper 24 that is the subject of our Patent No. 1,395,016.

The base frame 17 is also provided with a safety device 25 in accordance with the present invention and comprising three bell-crank like elements 26, 27 and 28, each having a pair of arms extending at an angle to one another.

Other elements 26 and 28 are pivotally mounted on respective flanges 29 and 30 that extend downwardly from carrier members 18 and 19 respectively, and inner element 27 is pivotally mounted midway between the two outer members on a cross bar 31 mounted on cross member 23. The corresponding extremities of the arms of elements 26, 27 and 28 are linked by a latch bar 32 and a ground-engaging bar 33.

The safety device 25 operates in an identical manner to the safety device 4 of Figure 1, being pivotable between a release position, shown in full lines in Figure 3, in which bar 33 engages a supporting surface and bar 32 is so disposed as not to obstruct the opening for the lifting forks, and a fork-latching position, shown in broken lines in Figure 3, in which the bar 32 is disposed behind the rear surface of the lifting forks and engages a flange 35 that projects rearwardly from lifting forks 34, thus restricting relative movement of the lifting forks and the base frame 17 in the direction of the length of the lifting forks.

In a variant of the above-described arrangement, the safety device 25 is provided with one or more further inner bell-crank like elements, such further elements being suitably disposed for the particular application and so as not to obstruct the opening for receiving lifting forks.

Figures 6 and 7 illustrate an alternative arrangement in which the open base frame 17 of Figures 3, 4 and 5 has a pair of fork tunnels 34' mounted on cross members 21 and 22.

Each fork tunnel 341 mounted on cross members 21 and 22. Each fork tunnel 34' is provided with a safety device 35' in accordance with the prevent invention and comprising a pair of bell-crank like elements 36 and 37, each element having a pair of arms extending at an angle to one another. The bell-crank like elements 36 and 37 are pivotally mounted on fork tunnel 34', one element being disposed adjacent each side of the tunnel. The free ends of the arms of elements 36 and 37 that extend near to the entry of the fork tunnel 34' are joined by a latch bar 38. The remaining free ends of the bell-crank like elements 36 and 37 are linked by a ground-engaging bar 39 that is extended to link together the two safety devices mounted on respective fork tunnels. The safety devices 35' operate in an identical manner to the above-described safety devices 4, 11 and 25.

The ground-engaging member or bar of any of the above-described safety devices may advantageously be provided with a wheel, such as a castor wheel, that in conjunction with like wheels on the item of fork-liftable equipment to which the safety device is fitted would provide mobility for such item of equipment when supported on a suitable surface.

The safety device of the invention may be applied to any item of fork-liftable equipment, such as a fork-mounted jib.

WHAT WE CLAIM IS: 1. A safety device comprising a latch adapted to be pivotally carried by an item of fork-liftable equipment so as to be pivotable between a release position in which the forkliftable equipment can be engaged and disengaged by lifting forks and a fork-latching position for latching the fork-liftable equipment to lifting forks when supported thereby, and a pendulous ground-engaging member connected to said latch and adapted to apply torque thereto, when unsupported, to rock said latch into its said fork-latching position but to be displaceable by ground engagement to permit movement of said latch to its said release position in response to placing of the said forkliftable equipment on a supporting surface.

2. A safety device according to claim 1, wherein the ground-engaging member termin atesinapador foot.

3. A safety device according to claim 1, wherein the ground engaging member terminates in a wheel.

4. A safety device according to claim 3, wherein the wheel is a castor wheel.

5. A safety device according to any one of the preceding claims, wherein the latch and the ground-engaging member are constituted by a pair of arms united at an angle at a pivot point in the manner of a bell-crank lever.

6. A safety device according to claim 5, wherein a pair of bell-crank levers have the corresponding extremities of their respective arms linked by stretchers of a length such that the bell-crank levers are spaced apart by a distance slightly exceeding the overall span of lifting fork of forks that is or are to be engaged thereby.

7. A safety device according to claim 6, wherein at least one bell-crank lever is so disposed between the said pair of bell-crank levers as not to obstruct lifting fork openings of said item of fork liftable equipment.

8. A safety device substantially as hereinbefore described with reference to and as shown in Figure 1 of the accompanying draw ingsi 9. A safety device substantially as hereinbefore described with reference to and as shown in Figure 2 of the accompanying drawings.

10. A safety device substantially as hereinbefore described with reference to and as shown in Figures 3,4 and 5 of the accompanying drawings.

11. A safety device substantially as hereinbefore described with reference to and as shown in Figures 6 and 7 of the accompanying drawings.

12. An item of fork-liftable equipment fitted with a safety device in accordance with any preceding claim.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. relative movement of the lifting forks and the base frame 17 in the direction of the length of the lifting forks. In a variant of the above-described arrangement, the safety device 25 is provided with one or more further inner bell-crank like elements, such further elements being suitably disposed for the particular application and so as not to obstruct the opening for receiving lifting forks. Figures 6 and 7 illustrate an alternative arrangement in which the open base frame 17 of Figures 3, 4 and 5 has a pair of fork tunnels 34' mounted on cross members 21 and 22. Each fork tunnel 341 mounted on cross members 21 and 22. Each fork tunnel 34' is provided with a safety device 35' in accordance with the prevent invention and comprising a pair of bell-crank like elements 36 and 37, each element having a pair of arms extending at an angle to one another. The bell-crank like elements 36 and 37 are pivotally mounted on fork tunnel 34', one element being disposed adjacent each side of the tunnel. The free ends of the arms of elements 36 and 37 that extend near to the entry of the fork tunnel 34' are joined by a latch bar 38. The remaining free ends of the bell-crank like elements 36 and 37 are linked by a ground-engaging bar 39 that is extended to link together the two safety devices mounted on respective fork tunnels. The safety devices 35' operate in an identical manner to the above-described safety devices 4, 11 and 25. The ground-engaging member or bar of any of the above-described safety devices may advantageously be provided with a wheel, such as a castor wheel, that in conjunction with like wheels on the item of fork-liftable equipment to which the safety device is fitted would provide mobility for such item of equipment when supported on a suitable surface. The safety device of the invention may be applied to any item of fork-liftable equipment, such as a fork-mounted jib. WHAT WE CLAIM IS:

1. A safety device comprising a latch adapted to be pivotally carried by an item of fork-liftable equipment so as to be pivotable between a release position in which the forkliftable equipment can be engaged and disengaged by lifting forks and a fork-latching position for latching the fork-liftable equipment to lifting forks when supported thereby, and a pendulous ground-engaging member connected to said latch and adapted to apply torque thereto, when unsupported, to rock said latch into its said fork-latching position but to be displaceable by ground engagement to permit movement of said latch to its said release position in response to placing of the said forkliftable equipment on a supporting surface.

4. A safety device according to claim 3, wherein the wheel is a castor wheel.

8. A safety device substantially as hereinbefore described with reference to and as shown in Figure 1 of the accompanying draw ingsi

9. A safety device substantially as hereinbefore described with reference to and as shown in Figure 2 of the accompanying drawings.