Vacuum lifting apparatus

Vacuum lifting apparatus 1 containing a lift tube 2 which is extendable and retractable in length, and is located in an upright disposition with an upper end 3 connectable to a fixed or movable anchorage point or support 4, the lift tube interior 6 being connectable to a vacuum generating structure and each end 3, 7 of the tube 2 provided with air sealing structure, valve means 10 to connect the interior of the lift tube 2 at a controllable level to atmosphere to regulate the vacuum therein and hence the axial extension of the lift tube 2, and a relatively rigid device 11 located within the lift tube 2, which device 11 is axially displaceable or extendable and retractable with the lift tube 2 and carries at a lower end a means 14 for engaging a load to be lifted, transported and lowered.

This invention relates to a vacuum lifting apparatus of the general type 
described in GB 2080764B. 
Whilst this known apparatus has been used for lifting all manner of objects 
its use has always been limited to lifting from directly above the load, 
as the lift tube is a flexible bellows which cannot accommodate side 
loading. Hence it has been impossible to offer a solution to lifting loads 
from a lateral location e.g., from inside a machine press or from under 
pallet racking or shelving or from inside a machine guard. Also it has 
become increasingly apparent that, when handling large boards and planks, 
unless the load is picked up exactly on centre-line it will not remain 
horizontal and, in un-trained hands, can be somewhat unnerving in 
operation. 
According to the present invention, there is provided vacuum lifting 
apparatus comprising a lift tube which is extendable and retractable in 
length, and is adapted to be located in an upright disposition with an 
upper end connectable to a fixed or movable anchorage point or support, 
the lift tube interior being connectable to a vacuum generating means and 
each end of the lift tube provided with air sealing means, valve means to 
connect the interior of the lift tube at a controllable level to 
atmosphere to regulate the vacuum therein and hence the axial extension of 
the lift tube, and a relatively rigid device located within the lift tube, 
which device is axially displaceable or extendable and retractable with 
the lift tube and carries at a lower end a means for engaging a load to be 
lifted, transported and lowered. 
A basic advantage of installing the axially displaceable or extendable 
device within lift tube is to ensure no additional bulky structures are 
required surrounding the lift tube. Also there is no fundamendal reduction 
in the lifting capacity of the appartus in accordance with the invention, 
except for that resulting from the weight of the additional components 
attached to the load engaging means, but basically the invention results 
in a rigidised lift tube, whereby the apparatus is capable, inter alia, of 
lifting and lowering lateral loads, remote from the centre line of the 
lift tube. 
The load engaging means may be attached directly to the lower end of the 
lift tube. Alternatively the load engaging means may be attached 
indirectly to the lower end of the lift tube, via a beam, which may be 
symmetrical, extending equally to opposite sides of the longitudinal axis 
of the lift tube e.g., with a load engaging means at each end, and 
possibly intermediate the two ends, (which arrangement is suitable for 
lifting sheets of timber, glass etc), or which may be asymmetrical, 
extending to one side only of the longitudinal axis of the lift tube, with 
a load engaging means carried at the end of this beam distal from the lift 
tube (which arrangement is suitable for penetrating pallet racking or 
shelving for instance). 
In detail, the lift tube may be extendable and retractable by being 
constituted by a bellows, preferably reinforced by a spiral spring. 
The axially displaceable or extendable device may, in one embodiment, be 
constituted by a telescopic device e.g., generally of piston and cylinder 
form, with an inner elongate member axially displaceable with respect to 
an outer elongate member, preferably with friction reducing or eliminating 
bearing means between the inner and outer members. Thus, if the inner 
member is of square section the bearing means may comprise four rollers 
located 90.degree. apart around the inner member, the periphery of each 
roller engaging one face of the member, while if the inner member is 
tubular, four balls instead of rollers may be employed, also located 
90.degree. apart, to engage around the inner member. Preferably, two sets 
of rollers or balls are provided, the sets being axially spaced apart. 
With a square section inner member, a rotating connection, also preferably 
incorporating axially spaced-apart bearing means, is required between the 
lower end of the inner member and the laterally extending member, if a 
facility for arcuate movement of the load engaging means, e.g. a laterally 
extending member, is required. 
The same principles can be used on an apparatus incorporating double or 
triple lift tubes, while if four, six or eight lift tubes were involved, 
preferably a piston and cylinder type extendable device would be replaced 
by an inverted scissor device to ensure complete rigidity e.g. when 
handling up to 1/2 ton loads on fully automated equipment. 
The apparatus may be floor mounted on a vertical column with at least one, 
and preferably two, arms interposed between the column and the apparatus. 
With one arm arrangement, the latter is pivotally attached to the column, 
while with a two arm arrangement a second arm is pivotally attached to a 
first arm which is pivotally attached to the column. 
Alternatively, the apparatus may be rendered mobile by being mounted on an 
overhead conveyor system. 
Preferably the laterally extending member is constituted by a beam. 
The load engaging means preferably takes the form of a suction foot. If 
however, this is unsuitable for the particular load to be handled, then 
this may be supplemented or replaced by mechanical and/or electromagnetic 
grippers.

In the drawings, vacuum lifting apparatus 1 comprises a lift tube 2 of 
known construction comprising an extendable and retractable bellows 
reinforced by a spiral spring. The lift tube 2 is adapted to be located in 
an upright disposition, as indicated in FIGS. 1, 3, 5 and 6, with an upper 
end 3 connected to a fixed support 4 (as illustrated in FIGS. 1 and 3) or 
a mobile support 5 (as illustrated in FIGS. 5 and 6). The lift tube 2 has 
an interior 6 connectable to a vacuum generating means (not shown) and the 
upper and lower ends 3, 7 of the lift tube 2 are provided with air sealing 
means, being an upper, rotary seal 8 and a lower seal 9. A valve means 10 
is connected to the interior 6 of the lift tube 2, to connect the interior 
6, in a controlled manner, to atmosphere, whereby the vacuum level within 
the interior 6, and hence the axial extension of the lift tube, is 
controlled, to provide the up and down movements required during load 
handling operations. Within the lift tube 2 is located a relatively rigid 
device in the form of a rod 11, e.g. of lightweight alloy, which rod 11 is 
axially displaceable, or extendable and retractable, simultaneously with 
the lift tube 2, as indicated by the arrow 12. The rod 11 carries at a 
lower end 13 means for engaging a load to be lifted, transported and 
lowered, which means is constituted by a suction foot 14 of known 
construction. The foot 14 may be attached to the rod 11 indirectly, via an 
interposed, laterally extending beam 15, as illustrated in FIGS. 1, 3, 5, 
and 6; or alternatively may be attached directly to the rod 11, as 
illustrated in FIG. 3A. The beam 15 may be asymmetrical, as illustrated in 
FIGS. 1, 3 and 5, with the valve means 10 located diammetrically opposite 
the beam to assist counterbalancing of the latter, or alternatively may be 
symmetrical, as illustrated in FIG. 6. 
The rod 11 is located within an outer, elongate casing 11A which, together 
with the rod 11, constitutes a piston and cylinder telescopic device. In 
this embodiment, the upper end 3 is attached to the casing 11A, which is 
in turn attached to the support 4 or 5. In the embodiment of FIGS. 1 and 
2, the rod 11 is of square section, and a friction-reducing bearing means 
is provided, comprising two axially-spaced sets of four rollers 16, 
located 90.degree. apart, and carried by the casing 11A, the periphery of 
each roller 16 engaging one of the four faces of the square rod 11. In the 
embodiment of FIGS. 3 and 4, the rod 11 is tubular, and two axially spaced 
sets of four balls 16A, also located 90.degree. apart, are carried by the 
casing 11A and engage around the rod 11. In the embodiment of FIGS. 1 and 
2, a rotating connection 17, also incorporating axially spaced-apart 
bearing means 18 is provided between the lower end of the rod 11 and the 
beam 15. 
The apparatus 1 is particularly adapted for manual operation, for which 
purpose a square "U"-shaped hand grip 19 is attached to a housing 20 of 
the valve means 10, whereby the apparatus 1 may be manually manoeuvred, 
particularly by rotation about the longitudinal axis 21 of the lift tube 
2, while a similar, square "U"-shaped valve actuation lever 22 is 
pivotally attached to the housing 20, for one-handed control by the 
operator. 
As illustrated in FIG. 5, the apparatus 1 may be floor mounted on a 
vertical column 23, with two arms 24, 25 interposed between the column 23 
and the apparatus 1, the second arm 25 being pivotally attached to the 
first arm 24, which is pivotally attached to the column 23. 
As illustrated in FIG. 6, the apparatus may, alternatively, be mobile by 
being mounted on an overhead conveyor system 26, and furthermore, as 
indicated in chain-dotted line, the beam 15 may be extended equally to 
opposite sides of the lift tube 2, with each end of the beam provided with 
a suction foot 14.