GB2032385A - A jack for lifting cylindrical loads - Google Patents

Abstract

A jack, especially a trolley jack, comprising a pair of arms (7) adapted to engage opposite portions of a drum (43) or other object brought between them, and actuating means (14 to 16) arranged to move the arms (7) in an upward direction to lift the drum (43), or other object, in which the arms (7), or respective portions (parts of 12) thereof, are moveable towards one another to engage the object (43), by the actuating means, prior to lifting. <IMAGE>

Description

SPECIFICATION Ajack The present invention relates to a jack, especially a trolley jack, for example one designed as a barrel or oil drum lifter/transporter.

Devices have already been proposed for lifting oil drums and then transporting them. One such device is a fork-lift truck. This requires a space between the drum and the ground so that its fork can be positioned underneath the drum prior to lifting.

An aim of the present invention is to enable an oil drum or like container to be lifted from the ground without the need for any support directly underneath the oil drum. With this aim in view, the present invention is directed to a jack, especially a trolley jack, comprising a pair of arms adapted to engage opposite portions of a drum or other object brought between them, and actuating means arranged to move the arms in an upward direction to lift the drum, or other object, in which the arms, or respective portions thereof, are movable towards one another to engage the object prior to lifting.

In one form of the invention, the arms are pivotably mounted, and the actuating means comprise extending means which are so coupled with the arms that, when the jack is positioned for use, extension of the extension means first pivots the arms so that they take hold of the object, and continuation of such extension lifts the arms together with the drum or other object.

Such a jack avoids any necessity of having clamping means and lifting means as individual units which have to be successively operated independently of one another, which would involve the user in two operations in order merely to lift the container from the ground prior to transport.

In another form of the invention, the jack is a trolley jack for carrying oil drums from one place to another, and the arms have respective pivotal portions each with an inwardly-curved surface so that, when the trolley jack is manoeuvred into a position for lifting an oil drum which is standing on one of its ends, the inwardly curved surface receives part of the cylindrical wall of the oil drum which is between the rolling rims thereof. It is not then necessary for the extension means to first pivot the arms so that they take hold of the oil drum; the rolling rim above the pivotal portions ensures a satisfactory lifting action.

Two examples of a jack in accordance with the present invention are illustrated in the accompanying drawings, in which: Figure 1 is a side elevational view of a trolley jack or barrel transporter; Figure 2 is a rear elevational view of the trolley jack shown in Figure 1, with some parts of the jack removed for greater clarity; Figure 3 is a plan view of the trolley jack shown in Figure 1; Figure 4 is a rear elevational view of a modified form of the jack illustrated in Figures 1 to 3; Figure 5 is a front perspective view of the jack shown in Figure 4; and Figure 6 is a rear perspective view of the jack shown in Figure 4, positioned ready for lifting an oil drum; and Figure 7 is an exploded perspective view of the modified trolley without its hydraulic unit.

Referring to Figure 1, a trolley jack comprises a main frame in the form of a U-shaped chassis 1 at the forward ends of the arms of which there are fixed castors 2, there being a swivel castor 3 at a rear end of the chassis. Upright posts 4 and 5 are fixedly mounted on the chassis 1, the posts terminating at a stay in the form of a horizontal plate 6 to which they are bolted.

Clamping means of the jack include a frame or side brace having an arm 7, vertical portions 8 and 9, a strut 10 and a further portion 11 projecting from the vertical portion 8. The portion 11 provides a pivot mounting for a curved plate 12. Only one such frame is visible in Figure 1, but Figure 3 shows that another similar frame is mounted on the other side of the jack, the jack being symmetrical about a vertical plane containing a longitudinal axis of the trolley.

As can also be seen from Figure 3, the frames are supported on the two posts 4 respectively, in a manner so as to be pivotable thereabout, by means of lugs 23 projecting laterally inwardly from the frames and embracing the posts. Since the lugs 23 can also slide along the posts 4, upward and downward movement ofthe frames is also possible.

At the rear-end of the trolley there is installed a totally sealed hydraulic lifting unit comprising a pump 14 and a single acting cylinder 15 from which extends a flanged piston rod 16 (the flange of which is hidden from view by the arm 7 in Figure 1). A hand lever 13, for operating the pump 14, is provided with a switching lever 41 at its free end, the switching lever being selectively adjustable to oneofthreeposi- tions; jacking; neutral, and release. These positions are for (a) lifting, (b) holding, for transporting, and (c) lowering. A chain 42 extends from the switching lever down along the hand lever 13 to an actuator 43 at the base of the cylinder 15 to effect such control.

The hand lever 13 is also coupled to the swivel castor 3 so that a swinging movement of the lever 13 about a vertical axis rotates the castor 3.

Turning now to Figure 2, a connecting plate 18 has an upper horizontal portion (part of which can be seen in Figure 3) bolted to a cross plate 19, which portion rests on the flange of the piston rod 16.

Respective ends of two rigid composite rods 17 are bolted to two lower end portions of the plate 18, the other ends of the composite rods being bolted to respective rear ends of the arms 7.

Each composite rod 17 is extensible or retractible by rotation of a centre portion 17a thereof. This centre portion has left-hand and right-hand internal screwthreading respectively at its two ends, which receive respective externally screwthreaded portions of the composite rod.

At the rear ends of the arms 7, the two ends of the cross plate 19 are respectively connected by way of double-headed pins 20. Figure 3 shows that each pin 20 extends through an elongate slot 22 in an upper portion of the rear end of one of the arms 7, the slot extending across the arm.

Also with reference to Figure 3, fourtwisted-plate mounts 24 with respective pairs of guide wheels 25 project towards the centre of the trolley jack. Only the top two such mounts are represented in Figure 3; the other two mounts are directly beneath the top two.

The trolley jack has a width of 29 < inches (0.75 metres), a length of 35.3/8 inches (0.90 metres) and an overall height of 21.3/4 inches (0.55 metres), the chassis 1 clearing the ground by 4.3/4 inches (0.12 metres).

When the trolley jack is to be used, it is wheeled up towards a metal oil drum (not shown) which is standing on end. To do this, the trolley can be pushed along by the hand lever 13, this lever at the same time being used to steer the trolley jack by being swung appropriately to one side or the other, the switching lever being in the neutral position at this stage. The wheel configuration of the trolley gives it a high degree of manoeuverability, the wheels being especially useful in flame-proof areas. When the trolley reaches the oil drum, the forward edges of the curved plates 12 hit the cylindrical side of the drum and move away from one another by a consequent swinging of the plates 12 about their pivot mountings.Then, as the trolley is pushed further forwards, the forward edges of the plates move back towards one another, to the position illustrated in Figure 3, at which point the guide wheels 25 act as buffers against the oil drum. The height of the curved plates 12 from the ground is such that they fit between the two rolling rims of the oil drum.

The switching lever is now moved to its jacking position, as a result of which operation of the pump 14 will raise the piston rod 16 of the cylinder 15 by hydraulic action. This is effected by rocking the hand lever 13 up and down in a vertical plane, and causes an upward force to be exerted on the connecting plate 18. This force is transmitted, as an upward and outward force, through the arms 17 to the rear ends of the arms 7. Initiallythe upper rolling rim of the oil drum resists an upward movement of the curved plates 12 and the arms 7, and consequently the rear ends of the arms 7 move outwardly. Such movement is allowed for by the elongate slots 22, for relative movement between the arms 7 and the cross plate 19, and by a certain amount of give in the structure, for example a slight bending of the cross plate 19.

Thus an initial extending of the piston rod 16 causes the arms 7 to pivot about the posts 4 so that the oil drum 13 is firmly clamped between the curved plates 12.

From the foregoing it will be appreciated that, when the trolley jack is manoeuvered into a position for lifting an oil drum which is standing on one of its ends, the inwardly curved sides of the curved plates 12 receive parts of the cylindrical wall of the oil drum which are between the rolling rims thereof.

As the piston rod 16 continues to be extended, the cylindrical side wall of the drum resists further inward movement of those plates, to an even greater extent than the upper rolling rim of the oil drum resists upward movement thereof. Thus the only remaining freedom of movement for the arms 7, underthe action of the hydraulic cylinder 15, is upwards. Continued extension ofthe piston rod 16 therefore causes the oil drum to be lifted clear of the ground. The hydraulic unit allows a filled drum weighing about 500 Ibs (250 Kgs) to be lifted by an operator using only one hand.

The switching lever is now moved to its neutral position, whereupdn the hydraulic fluid in the cylinder 15 is trapped to maintain the extended position of the piston rod 16, and the trolley jack is pulled along by the hand lever 13 with which the trolley can also be steered as previously explained.

On reaching the desired re-location for the oil drum, the switching lever 13 is moved into release position, causing hydraulic fluid to flow out from the cylinder 15 under gravitational pressure. Thus the oil drum is lowered to the ground, and the trolley can be pulled away to leave the drum in its new location.

In the modified form shown in Figure 4, plate 18 and arms 17 shown in Figure 2 are absent, and an adjusting bar 31 extends between and has its two ends respectively attached to the rear ends of the two arms 7. The length of the bar 31 is adjustable in the same way as each of the arms 17 shown in Figure 2. Thus the bar 31 can be used to vary the spacing between the rear ends of the arms 7. The trolley jack has a height of 28 < inches (0.73 metres), a width of 27 < inches (0.71 metres), and a length of 36 inches (0.91 metres).

The method of manually operating this modified form of the trolley jack is the same as for the trolley jack illustrated in Figures 1 to 3. However, the adjusting bar 31 enables the arms 7 to be preset in such a manner that, when the trolley, as shown in Figure 5, is manoeuvered into position for lifting an oil drum 43 which is standing on one of its ends as shown on Figure 6, the inwardly curved sides of the curved plates 12 meet respective portions of the cylindrical wall of the oil drum 43 which are between the rolling rims 44 and 45 thereof, the fit being sufficiently close to avoid the necessity of using any initial extending of the piston rod 16 to pivot arms 7 for a firm clamping of the oil drum 43 between the curved plates 12.

Thus these plates 12 are already sufficiently close togetherto ensure that, when the arms 7 are raised, the full weight of the oil drum 43 can be supported by the engagement of its upper rolling rim 44 on the upper edges of the curved plates 12, so that the oil drum 43 can be lifted clear from the ground by extending the piston rod 16.

Figure 7 shows various parts of the trolley in greater detail. Thus the main frame or chassis assembly comprises the main frame or U-shaped chassis 1, plastic caps 50, nylon guides 51 and Allen screws 52.

Each fixed castor 2 comprises a wheel 53, a bush 54, an oil cup 55, and a wheel bolt 56 and nut 57. The side brace assemblies include the arms 7, bushes 58, the curved plates 12, pivots 59 and circlips 60.

The adjusting bar assembly is constituted by the adjusting bar 31 itself, pivots 61 with left and right-hand pivot portions 62 and 63, a lock nut 64, bolts 65, nuts 66 and washers 67. Other parts shown in Figure 7 are the posts 4, the stay 6, collars 68, washers 69 and Allen screws 70.

It would be possible to dispense with one of the curved plates 12 if this were replaced, for example, by an elongate roller to provide an upright opposing buffer for effective operation of the other curved plate 12.

Since the hydraulic unit is totally sealed, it does not require maintenance servicing. However, in the event of failure of the unit, it is merely necessary to unscrew bolts 21 (see Figure 2 or 4), after which the unit is freed from the chassis to allow replacement.

The illustrated trolley jack can be made as a robust, simple to operate piece of equipment, to handle standard 45 gallon (22 litre) drums having a gross weight of up to 660 Ibs (330 Kgs).

Of course, the actual contents of the drum which is lifted may be a substance other than oil, for example it may be an ink, a coating varnish, an adhesive or a slurry.

Claims (22)

1. A jack, especially a trolley jack, comprising a pair of arms adapted to engage opposite portions of a drum or other object brought between them, and actuating means arranged to move the arms in an upward direction to lift the drum, or other object, in which the arms, or respective portions thereof, are moveable towards one another to engage the object prior to lifting.

2. A jack according to claim 1, in which the arms have pivotal portions arranged to engage a projecting part of the object, for example an upper rolling rim of an oil drum, as the actuating means are operated, parts of the pivotal portions constituting those portions which are moveable towards one another.

3. A jack according to claim 2, in which the pivotal portions each have an inwardly curved surface, the concave surfaces facing one another

4. A jack according to any preceding claim, in which the arms are pivotably mounted.

5. A jack according to claim 4, in which the relative angular positions of the arms are adjustable by adjusting means.

6. Ajack according to claim 5, in which the adjusting means comprise an adjusting bar con nected between the arms.

7. A jack according to any one of claims 1 to 4, wherein the manner in which the actuating means are arranged to move the arms in an upward direction is such as to urge the arms into clamping or gripping contact with the object.

8. A jack according to any preceding claim, wherein the actuating means comprise a hydraulic lifting unit.

9. A jack according to claim 8, in which the hydraulic lifting unit is totally sealed.

10. A jack according to claim 8 or 9, in which the hydraulic lifting unit is removable from the rest of the jack for inspection, repair or replacement.

11. A jack according to claim 8,9 or 10, further comprising a hand lever connected to actuate the hydraulic lifting unit by a pumping action.

12. A jack according to any one of claims 8 to 11, in which a manual selector is coupled to the hydraulic unit to be selectively positioned for (a) lifting, (b) holding, for transporting or (c) lowering.

13. Ajack according to claim 12 appended to claim 11, in which the manual selector is mounted on the hand lever.

14. A jack according to any preceding claim, being a trolley jack.

15. Ajack according to claim 14, having at least one wheel mounted pivotably for steering.

16. A jack according to claim 15, appended to claim 11, in which the hand lever is coupled to the pivotably mounted wheel or wheels so that the hand lever can be used to pull the trolley jack along and to steer it at the same time.

17. A jack according to any one of claims 14 to 16, having a U-shaped chassis.

18. A jack according to claim 17, with the actuat- ing means at the base of the "U".

19. Ajack according to claim 17 or 18, with fixed castors on the arms of the "U".

20. Ajack according to claim 17, 18 or 19, appended to claim 15, with the wheel or wheels which are pivotably mounted being at the base of the "U".

21. A jack according to any one of claims 17 to 20, in which the arms which are adapted to engage opposite portions of a drum or other object are positioned respectively above the arms of the U-shaped chassis.

22. Atrolley jack substantially as described herein with reference to Figures 1 to 3, or Figures 1 to 3 modified in accordance with Figures 4 to 7 of the accompanying drawings.