AU697023B2 - Drum lifting attachment - Google Patents

Description

Regulation 3.2

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

1 a a

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*i a ar *a a *aa a Names of Applicants: Actual Inventors: Address for Service: Lyndon Mervyn SMITH, Lynda May SMITH and Byron Victor SMITH Lyndon Mervyn SMITH, Lynda May SMITH and Byron Victor SMITH 4EN-MAD E AT-ENT- RNEY, 5th Floor, 150 Grenfell-Street, F-Ae^JAnJ Q ,L 4 L A Iur- i; LaoL/ f L"D LlC inventioniT: iDr LiftAng A ttachment Lu Invention Title: Drum Lifting Attachment" Details of Associated Provisional Application No: PN 4879 dated 18th August, 1 The following statement is a full description of this invention, including method of performing it known to the applicants.

-1- This invention relates to a novel drum lifting attachment. The lifting of drums and barrels that are too heavy for manual lifting generally involves some lifting device which requires securing in some manner to the drum or barrel to be lifted.

Prior Art means for the attachment of lifting devices to a drum or barrel generally involve a plurality of grapples each connected to a flexible lifting chain, with these chains gathered to a point where a lifting hook may be attached. The grapples generally engage the rim of the drum or barrel and upon lifting of the object tension the lifting chains, thereby providing a positive gripping action of the grapples such that the drum or barrel may be lifted. Prior to tensioning the chains the grapples are not positively engaged on the rim and can be relatively easily dislodged. The effectiveness of the grapple arrangement depends upon the correct engagement of the grapple with the rim of the drum during the lifting process. Unfortunately, it is difficult to ascertain S 15 prior to the lifting operation whether or not a grapple will fail to positively engage the rim.

o This form of prior art means has in the past been known to fail if grapples have been dislodged from their original engagement and consequently the drum or barrel has been dropped, suffering damage and presenting a significant danger to personnel in the vicinity of the lifting operation. In situations where the drum contains dangerous liquids, the spillage of such liquids upon damage sustained to the drum may present a further danger to personnel involved in the lifting operation. In addition, the likelihood of failure occurring with this form of prior art arrangement increases as the weight of the object to be lifted increases in that partial engagement of a grapple may not fail for small loads yet would be more likely to fail for larger loads.

-2- Whilst the prior art means is removable the operation is somewhat cumbersome and depends upon the number of grapples involved in securing the drum to the lifting device.

It is an object of this invention to provide a more reliable means than known prior art for the attachment of lifting devices to drums or barrels.

It is a further object of this invention to provide a more reliable means of attaching a lifting device whilst retaining the feature of removability. This enables the means to be used multiple times with different drums.

It is still a further object of this invention to provide a reliable attachment means which is relatively quicker to secure and release than prior art devices.

In one embodiment of this invention an adjustable hoop or ring is provided with extending members joined by a flexible tether. This adjustable ring is preferably placed directly under the rim of the drum and is adjusted such that the ring firmly grips the outer surface of the drum. Adjustment of the ring is S 15 provided for by a mechanical over centre toggle clamp with an extending handle to assist an operator in the actuation of the clamp to firmly grip the :drum. The extending handle may be used to both tighten the ring around the drum and also to loosen the ring from around the drum. This feature provides for the relatively quick attachment and removal of the adjustable ring.

The ring has firmly attached to it angled tension members which r iay be attached to flexible chains as previously described for the purpose of attaching the ring assembly to a lifting device These angled tension members act to compound the gripping of the ring to the drum as the drum is lifted by providing an inwardly acting force to the ring.

In addition to the compounding of the gripping force of the ring during the lifting operation, the distribution of the lifting force around the entire circumference ofthe drum rim significantly improves the reliability of this attachment device as compared to existing prior art.

-3- As a further improvement to safety, to reduce the likelihood of the accidental release of the toggle clamp a chain, or similar flexible means, is provided with one end firmly attached to the lifting attachment with the other end provided with a coupling means to be releasably attached to the toggle clamp handle. Prior to initiating the lifting process, the flexible restraining means is releasably attached to theltoggle clamp handle when the toggle clamp is in its secured position, thereby restraining the toggle clamp handle and reducing the risk of accidental release of the clamp.

An embodiment of the invention is described hereunder in some detail with reference to and is illustrated in the accompanying drawings, in which: Fig 1 is a perspective view of the adjustment mechanism and the ring; Fig 2A is a section of the drum lifter assembly during a lifting operation; Fig 2B is a vector diagram indicating how the lifting force enhances the grip of the ring around a drum; and 15 Fig 3.is a fragmentary perspective view, illustrating details of the toggle clamp, and drawn to a larger scale.

i In this embodiment, a drum lifting attachment 10 comprises an open ring 11 which has two ends 12 and 13. Each end 12 and 13 is rolled to provide bearing surfaces for a pivot pin of a toggle clamp 14.

Toggle clamp 14 comprises a relatively long link 15 and a relatively short link 16, each link comprising a pair of spaced bars and respective pivot pins 17 and 18 both pass through pairs of apertures in the bars, and rolled ends of the ring, to provide the connections between the links and the ring ends, The bars of the long link are spaced apart wider than the short link so that the short link can pass between them upon toggle action.

The short link 16 is provided with a threaded aperture 20 which threadably receives an end of an adjustment screw 21, the adjustment screw being on the inner end of a handle 22, the handle 22 passing through a sleeve -4- 23 and being rotatable therein, the sleeve 23 being portion of a pivot control plate 24 fast with, and extending at right angles to, handle 22. Plate 24 is pivoted at 25 to the swinging end of the long link 15. The handle is thereby effectively fast with both the short link 16 and control plate 24, and the distance between the pivotal axis of pin 18 and the longitudinal axis of handle 22 is substantially the same as the distance between the pivotal axis of pivot 25 and the same longitudinal axis of handle 22, so that in this embodiment the short link 16 and the effective length of the pivot control plate 24 are both about the same although this is not necessary in all instances. However as shown best in Fig 1, the arrangement has the distinct advantage that upon opening up of the open ring 11i by release movement of handle 22 assists in opening the ring not merely circumferentially as in the case of prior art toggles, but also opening the ring radially so that it is very easily removed from a drum for example.

1 A possible hazard can exist in that the handle 22 can be inadvertently 15 moved from a clamping to a relaxed position for the open ring 11, and to *o provide a double safety feature, a short length of chain 26 is secured at its inner end to the open ring 11, and the handle outer end carries on it a slide ring 27 of larger diameter than handle 22, but only marginally larger than a circular Splate 28 on the swinging end of handle 22.

There are four lifting bars designated 31 formed from two lengths of bar T. stock, each bar 31 depending downwardly to the open ring 11, and sloping outwardly at the same time but the lower ends slope inwardly at 32 to provide a 6 recess 33 in each instance which accommodates the projecting annular rim 34 of a drum 40 (Fig 2B).

The upper ends of bars 31 are joined by a short length of chain 35 which has an odd number of links (as shown, seven links), the centre link 36 being supported by a rectangular base 37 of a U-shaped suspension loop 38 itself i i i carried by a depending hook 39 of some lifting means which forms no part of this invention.

Fig 2B illustrates the radially inner vectors which are generated by the lifting forces in the lifting bars 31. These vectors indicate how the lifting force will add to the clamping force imparted by the actuation of the toggle clamp 14, further adding to the security of the lifting device.

Consideration of the above embodiment will indicate that there are a number of valuable features in this invention.

Firstly, the novel toggle arrangement has the function of opening up the ring 11 to a much larger diameter thereby greatly simplifying the manipulation of the ring both for positioning and removing from the drum, The use of the safety chain 26 removes any possibility of the ring being inadvertently opened during a lift. The adjusting screw 21 provides a "fine tune" adjustment, while as oshown the long link 15 has alternative apertures for the pin 17 for coarse 15 adjustment of the circumference of the open ring 11. The pressure which is .o applied to the outside of the drum is not localised as in the case of grapples, °but is spread over the whole area of the ring 11 when it is clamped around a drum. The chain arrangement is such that the existence of a tilted link is avoided, and the lifting bars 31 are thereby symmetrical about a vertical axis during any lift, O 0 -6-

Claims (6)

1. A drum lifting attachment for lifting a drum by firmly gripping its outer surface beneath an annular outstanding projection, comprising an open ring having two co-operable portions of a toggle clamp pivoted to adjacent ends of said open ring and operable upon closure of said clamp to reduce the effective circumference of said open ring, and adjustment means coupling said toggle clamp portions which are adjustable in length, and lifting members extending upwardly and radially inwardly from said ring, from spaced locations around said ring.

2. A drum lifting attachment according to claim I wherein said open ring comprises two ends spaced from one another, pivot pins coupling a relatively long link and a relatively short link to respective said ends for pivotal movement with respect thereto, 15 a pivot control plate, a further pivot pin pivoting the pivot control plate to u o a swinging end of said long link, a handle fast with both said pivot control plate 1 and said short link retaining said short link and control plate spaced and So-. generally parallel relationship with one another, all in a toggle configuration wherein said links lie generally contiguous 20 and said handle is relatively close to said ring when said ring effective 0 circumference is contracted in a clamping mode, and said handle projects outwardly from said ring and increases said ring effective circumference when in a release mode.

3. A drum lifting attachment according to claim 2 wherein said pivot control plate comprises a sleeve, said handle extending through said sleeve and having a threaded end, said short link having a threaded aperture threadably engaged by said handle end.

7. 4. A drum lifting attachment according to any preceding claim wherein said long link comprises a pair of bars which are sufficiently spaced from one another to permit passage between them of said short link upon toggle actuation of said links. 5. A drum lifting attachment according to claim 2 wherein said relatively long link comprises two pairs of pivot pin apertures selectively engagable by a said pivot pin for coupling to a said ring end, for varying the effective circumference of said ring. 6. A drum lifting attachment according to claim 2 further comprising a safety chain fast at one end with said ring and a slide ring at the other end of said safety chain releasably engagable over said handle to restrain said handle against movement from a clamp position to a release position. 7. A drum lifting attachment according to any preceding claim wherein there are two said lifting members of bar stock each having an inverted shape, lower ends of said lifting members being secured by welds to said ring, and further comprising a length of suspension chain joining the upper portions of said shape bar stock.

8. A drum lifting attachment according to claim 7 further comprising a suspension loop surrounding said suspension chain, and having a flat surface which, in use, retains a central link of said suspension chain horizontal.

9. A drum lifting attachment substantially as hereinbefore described with rk.-rence to and as illustrated in the accompany drawings. DATED this 15th day of August, 1996 LYNDON MERVYN SMITH, LYNDA MAY SMITH and BYRON VICTOR SMITH By their Patent Attorney KEN-MAdBERN GoLLS^ -Q LD -e C? l ,A A C& i i. I ABSTRACT A ring or hoop (11) has an effective circumference which is adjustable by action of a toggle clamp to either clamp around a drum (35) beneath its rim, or be released. The toggle clamp (14) has a handle (22) which retains a pivot control plate (24) generally parallel to a short link so that by swinging the handle (22) from the clamp mode to the release mode, ends of the ring or hoop (11) are readily separated diametrically (by the distance between link (16) and control plate as well as being separated circumferentially. a *a a a ,9 a* eo 90 oe i i