GB2291855A

GB2291855A - Lightweight Crane

Info

Publication number: GB2291855A
Application number: GB9515710A
Authority: GB
Inventors: James Donaghue
Original assignee: SCOTATLAS Ltd
Current assignee: SCOTATLAS Ltd
Priority date: 1994-07-30
Filing date: 1995-07-31
Publication date: 1996-02-07
Anticipated expiration: 2015-07-31
Also published as: GB9515710D0; GB2291855B

Abstract

A lightweight crane (1) is provided so as to be mountable at the longitudinal centre line of a small commercial vehicle (2, Fig 2) and comprises a base (3) including a plate (3A) which can be bolted to the vehicle floor to position the crane (1), a column (5) rotatably mounted on the base (3) and an extendable telescopic boom (7A, 7B, 7C) carried by the column (5) through an upper support formation (8) forming a "T" with the column. One leg (8C) of the "T" supports a winch (10) for the crane lifting line (11). Setting of the boom (7) in the vertical plane is achieved by a rod (13) located between the boom and the column. Slewing and boom extension/retraction may be effected purely manually but in a preferred embodiment any one of these operations, especially boom retraction, is achieved by force or power means. To this end (i) a clamp (18, Fig 4) enables boom retraction by the winch (10), and (ii) a spring device (20) biases the boom to the extended condition. A gear drive (G) may be provided for crane slewing. <IMAGE>

Description

"LIGHTWEIGHT CRANE" The present invention relates to a lightweight crane for use on small commercial vehicles e.g. light lorries, pick-up trucks and the like.

Loader devices especially in the form of cranes are well established for use on lorries. However, generally these have been intended for use on heavier type lorries e.g. 5 tons or greater. Previous such lorry cranes have comprised a column which was adapted for fitting on the lorry, either on the cargo platform of the lorry or on the lorry chassis, and a boom arrangement supported by the column. The boom has comprised pivotal sections which were placed in an extended condition by hydraulically operable piston - cylinder devices, and generally setting and operation of the crane was achieved hydraulically.

These prior cranes were complex, heavy and relatively expensive, especially due to the presence of precision hydraulic equipment and this has precluded their adoption on smaller vehicles. It is the principal object of the present invention to provide a lightweight crane which is especially suitable for use on smaller commercial vehicles.

Therefore the present invention broadly provides a lightweight crane arrangement for fitting at the longitudinal centre line of a small commercial vehicle; the crane comprising a base including means for fitting the base on a vehicle, a column upstanding from the base, means permitting the column to rotate about its longitudinal axis relative to the base, a support formation fitted at the top of the column, a telescopic boom including a base section secured to said support formation and at least two further telescopic sections, and means e.g. a rod to maintain the setting of the boom.

Slewing of the column about its longitudinal axis and extension of the telescopic boom can both be achieved by purely manual operations while a suitable winch can be provided for the crane lifting line; the winch preferably comprising an electric winch. Preferably the support formation and the column define a "T", one leg of this "T" supporting the boom while the other opposing leg of the "T" supports the winch for the crane lifting line.

The column preferably comprises a rectangular sectioned box structure, and said base section of the boom is preferably the same. The support formation can include cheek plates on either side of said base section of the boom and bonded to said section.

Preferably the boom is raised or lowered by adjustments of the rod means. The rod means preferably comprise a compression strut between the boom or support formation and the column. The parts of the crane can be made from suitable steel.

In a preferred embodiment, the boom can be retracted from the extended condition by power means, and preferably these power means comprise the winch for the crane lifting line. A releasable securing device can be provided at the outer end of the boom to tether the lifting line whereby inward line pulling by the winch causes retraction of the boom. Additionally, the boom may be placed in an extended condition by a force means and preferably these force means comprise a biassing device, e.g. spring means, serving to bias the boom automatically towards an extended condition. In a further preferred embodiment slewing of the crane is achieved by means of a gear drive which may be manually operated although an electric gear drive is also possible.

Embodiments of the present invention will now be described by way of example with reference to the accmpanying drawings wherein: Fig. 1 shows a side elevation of a lightweight crane for use on a small commercial vehicle, in accordance with the present invention; Figs. 1A and 1B show the section X-X and Y-Y in Fig.

1 to a larger scale; Fig. 2 shows a rear view of a light platform lorry with the crane of Fig. 1 fitted, the crane being shown in a retracted condition; Fig. 3 shows a schematic plan view of the lorry of Fig. 3 with the installed crane; Fig. 4 shows the crane of Fig. 1 with modifications so as to be in accordance with a further embodiment of the invention: and Fig. 5 shows the boom of the crane of Fig. 4 in the fully retracted condition.

Referring to the drawings, an economic lightweight crane 1 for use on small commercial vehicles 2 (Figs.

2/3) for example light lorries, pick-up tucks, vans etc.

comprises a base 3 including a fitting plate 3A whereby the base 3 can be secured to a suitable part of the vehicle e.g. to the cargo platform 4 by means of bolts.

The base 3 is of cylindrical form. A column 5 of rectangular box form is carried by the base 3 and, for crane slewing, is rotatable about its longitudial axis L - L, this being achieved by a cylindrical cup 6 secured to the foot of the column 5 overlying the cylindrical base 3 with suitable bearing means (not shown) between the cup 6 and the base 3. The column 5 can rotate through 3600.

A telescopic boom 7 has its base section 7A bonded to cheek plates 8A. 8B of a boom support/reinforcing structure 8 by welding and the structure 8 is pivotally attached to the columm 5 by a pin 9. As can be seen in Fig. 1 the column 5 and the structure 8 define a "T" formation, with a portion 8C opposite the cheek plates 8A/B defining a leg of the "T" serving to support an electric winch 10 for the crane lifting line 11. An end of the section 7A can overlie the column 5, and the section 7A can be made from the same box material as the column 5. The parts of the crane 1 are preferably made from suitable steel material.

A special feature of the crane of Fig. 1 is that it can load effectively from either side of the vehicle 2 and to this end the crane 1 is adapted for fitting at the centre line C-C of the vehicle, and has its boom 7 provided with at least two additional telescopic sections 7B, 7C. The outer section 7B includes a pulley wheel 12 for the lifting line 11 which can run within the boom 7.

Vertical setting of the boom 7 is achieved by a rodform compression strut 13 which has one end pinned to the structure 8 while the other end is supported on cheek plates 14A, 14B on the column 5, via lateral pins 13A, 13B on the strut 13.

Setting of the boom 7 can be varied by adjusting the position of the strut 13, and for this purpose the cheek plates 14A, 14B can include a series of inclined grooves 15 to receive the.pins 13A, 13B. By having both crane slewing and boom extension achieved by purely manual operations the need for expensive operating mechanisms can be avoided. The electric winch 10 can be driven from the vehicle battery via a simple electric control device (not shown).

Means are preferably provided to limit the outward movement of each of the telescropic sections 7B, 7C, and for example these means may comprise loocking pins (schematically indicated as items 16 in Fig.l).

Although of lightweight construction, the crane 1 is capable of lifting substantial loads, even in the extended condition (Fig. 1), and it is envisaged a load of 500 Kg could be lifted in this condition. By way of example the crane 1 could have an extended length of about 2100 m.m. with about half that length in the retracted condition.

The crane 1 can be positioned at any convenient longitudinal position on the vehicle, and a preferred position is at the rear of the cargo platform 4 as shown in Fig. 3.

Modifications are of course possible. For example, the means for setting the boom could be by rod means other than the compression strut 13.

In certain lifting and loading operations at the vehicle 2 using the crane 1, it may be desirable to retract the boom 7 by a certain degree to facilitate positioning of the lifted article (load) on the vehicle platform 4. The assist in this situation, it is proposed in a further inventive embodiment to arrange for the boom 7 to be retracted by power means instead of relying on manual boom retraction which may be difficult to effect especially if the load is heavy. In the crane 1 of Fig. 4 the electric winch 10 is used for these power means and this is achieved, in this example, by providing a clamping device 18 at the outer end of the boom 7 which device 18 is operatively set stable to hold the line 11 on the pulley wheel 12 thereby tethering the line 11 at the outboard end of the boom 7, so that inward line pulling by the winch 10 causes the boom 7 to retract.The clamping device 18 preferably includes a quick release operating handle 19. Further, a force means can be provided whereby the boom 7 is placed in the extended condition without the need for manual extension. In Fig. 4, these force means are constituted by a "spring" device 20 which automatically forces the boom 7 towards the extended condition shown in Fig. 4. In particular, in the example of Fig. 4 the spring device 20 is in the form of a piston-cylinder comprising opposed cylinders 21, 22 receiving a common rod 23,the cylinders 21, 22 being held by respective holders 24, 25 at the end sections of the boom: the device 20 can be pneumatically or hydraulically operable but a mechanical spring device would also be possible. The technology of such devices is well established in the art.Fig. 5 shows the boom 7 in the fully retracted condition with the device 20 compressed such that the rod 23 is now substantially wholly within the cylinders 21, 22. A lock, for example in the form of a pin located in hole 26, will be provided to hold the boom 7 in the retracted/compressed state of Fig. 5. Also suitable further holes 27A, 27B, 27C etc can be located on the various sections 7A-7C of the boom whereby the boom may be set by means of a locating pin in a selected intermediate position between the retracted (Fig. 5) and fully extended (Fig. 4) conditions. A gear drive G is present in the crane of Fig. 4 for slewing of the crane in place of pure manual slewing and comprises a spur wheel 6A and an engaging pinion 6B mounted on support plate 28, pinion 6B being rotatable by handle 29 for appropriate slewing of the crane. Pinion 6B could be driven by an electric motor (power say from the vehicle battery) if preferred.

Whereas Figs. 2 and 3 show the crane 1 mounted at the rear of the vehicle platform 4, it will be appreciated that the crane could be located at a different position on the vehicle, and the crane may be modified e.g. by shortening the column 5 to suit a particular mounting location.

Claims

1. A lightweight crane for fitting on a small commercial vehicle, especially at the longitudinal centre line of the vehicle, comprising a base including means for fitting the base on a vehicle, a column upstanding from the base, means permitting the column to rotate about its longitudinal axis relative to the base for crane slewing, a support formation fitted at the top of the column, a telescopic boom including a base section secured to said support formation and at least two further telescopic sections and locating means to maintain the setting of the boom relative to the column in a vertical plane.

2. A lightweight crane as claimed in claim 1, wherein said locating means comprises a rod device.

3. A lightweight crane as claimed in any one of claims 1 and 2, including a winch for a crane lifting line.

4. A lightweight crane as claimed in claim 3, wherein said winch is an electrically driven winch.

5. A lightweight crane as claimed in claim 3, wherein the support formation and the column define a "T", one leg of this "T" supporting the boom while the other opposing leg of the "T" supports the winch for the crane lifting line.

6. A lightweight crane as claimed in any one of the preceding claims, wherein the column comprises a rectangular sectioned box structure.

7. A lightweight crane as claimed in any one of the preceding claims, wherein said base section of the boom comprises a rectangular sectioned box structure.

8. A lightweight crane as claimed in claim 7, wherein the support formation includes cheek plates on either side of said base section of the boom and bonded to said section.

9. A lightweight crane as claimed in claim 2, wherein the rod device comprises a compression strut between the boom or support formation and the column, the boom being raised or lowered by adjustment of the rod device.

10. A lightweight crane as claimed in any one of the preceding claims, wherein any selected one of crane slewing, and boom extension and contraction is achieved purely manually.

11. A lightweight crane as claimed in any one of claims 1 to 9, wherein retraction of the boom from an extended condition is achieved by a drive means.

12. A lightweight crane as claimed in claim 11, when dependent on claim 3, wherein said drive means comprises said winch for the crane lifting line.

13. A lightweight crane as claimed in claim 12, wherein releasable tethering means are provided for selective tethering of the lifting line at the outer end of the boom whereby inward line pulling by said winch can cause retraction of the boom.

14. A lightweight crane as claimed in any one of claims 1 to 9 or 11 to 13, including force means to move the boom towards an extended condition.

15. A lightweight crane as claimed in claim 14, wherein said force means comprises a spring device serving to bias the boom automatically towards an extended condition.

16. A lightweight crane as claimed in claim 15, wherein means are provided to lock the boom in a semi or fully retracted condition with said spring device compressed.

17. A lightweight crane as claimed in any one of the preceding claims, wherein a gear drive is provided for crane slewing.

18. A lightweight crane for mounting on a small commercial vehicle comprising base including means for fitting of the base on a vehicle for location of the crane, a column upstanding from the base, a support formation at the top of the column, an extendable boom carried by said support formation and including at least one telescopic section, a winch for a crane lifting line for the lifting of a load, and means to enable said winch also to retract said boom selectively by means of said lifting line.

19. A lightweight crane substantially as hereinbefore described with reference to and as illustrated in Figs. 1 to 3 or Figs. 4 and 5 of the accompanying drawings.