GB2349833A

GB2349833A - Crane

Info

Publication number: GB2349833A
Application number: GB0004744A
Authority: GB
Inventors: Alan Baker
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-03-11
Filing date: 2000-03-01
Publication date: 2000-11-15
Also published as: GB9905450D0; GB0004744D0

Abstract

A crane has a base comprising upper part 12 rotatable on a vertical axis 16 about fixed lower part 10. Arm 18 is horizontally pivoted 14 on the upper part. A linkage is pivotable relative to the arm and includes first link 22 moving parallel to the arm, second link 24 pivotally interconnecting the arm and first link 22 at a point adjacent to the base and third link 26 pivotally interconnecting the arm and the other end of the first link. Optionally the linkage may include a fourth link 30 and fifth link 32 as shown below. Hook 34 is attached to the end of the third or fifth link. In operation, pivoting of the arm about the base moves the hook in a vertical circle centred on the horizontal axis, whereas manipulation of the linkage varies the radius of the circle and the reach of the hook. The crane can either be a full size machine, wherein rotation of the arm and movement of the linkage are controlled by electric motors, or a toy operated by hand lever 20 to rotate the arm and either hand lever 28 or hand-wheel (42) to operate the linkage.

Description

2349833 ""Crane" This invention relates to a crane having a principle of

operation which is particularly, though by no means exclusively, suitable for a toy.

The object of the invention is to provide a crane capable of lifting and positioning loads within a vertical circular plane which extends both above and below its base.

A further object is to provide a crane capable of lifting and positioning loads within a spherical spacial envelope which extends both above and below its base.

According to the invention, a crane comprises a base, an arm which is pivotable at one end about a horizontal axis on the base, and a linkage which is pivotable relative to the arm and is provided with means for carrying a load, the arrangement being such that pivoting of the arm moves the means in a circle lying in a vertical plane and centred on the axis, and pivoting of the linkage varies the radius of said circle and thus the reach of the means.

Preferably, the base comprises a fixed lower part and an upper part which carries the horizontal axis and is rotateable relative to the lower part about a vertical axis, whereby the means can be rotated about the vertical axis.

Preferably, the linkage comprises a first link constrained to move parallel to the arm; a second link pivotally interconnecting the arm and that end of the first link adjacent to the base; and a third link parallel to the 2 second link, pivotally interconnecting the arm and the other end of the first link, and extending beyond the arm.

Preferably, also, the linkage additionally comprises a fourth link pivotally connected at one end to a point on the arm spaced from the point of pivotal connection between the arm and the third link, and a fifth link pivotally connected at one end to that end of the third link remote from the first link and at an intermediate point to that end of the fourth link remote from the arm, the load- carrying means being attached to that end of the fifth link remote from the third link.

Preferably, the point of pivotal connection of the fourth link to the arm is disposed further from the horizontal axis than the point of pivotal connection between the arm and the third link, the arrangement being such that the third and fourth links cross each other.

Preferably, also, two parallel third links and two parallel fifth links are provided.

Alternatively, in a simpler configuration the load- carrying means are attached to that end of the third link remote from the first link, the fourth and fifth links being omitted.

The crane may comprise a toy wherein a first handoperated lever is fixed to the arm and a second hand- operated lever is fixed to a suitable part of the linkage.

The crane may comprise a toy wherein a first handoperated lever is fixed to the arm and a second hand- 3 operated lever consists of an extension of the second link at that end remote from the arm.

The first and second hand-operated levers are preferably disposed adjacent to each other so as to be 5 capable of simultaneous operation with one hand.

The crane may comprise a toy wherein the second link pivotally interconnects that end of the first link adjacent to the base and that end of the arm which is pivotable about the horizontal axis, a hand- operated lever being fixed to the arm and at least one hand-wheel being fixed to a spindle which is rotateable about said axis and fixed to the second link.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, of which:Figure 1 is a side elevation of one embodiment of a toy crane; Figure 2 is a side elevation of an alternative form of hook for same; Figure 3 is a section on the line 33 in Figure 2; Figure 4 is a section on the line 4-4 in Figure 1; Figure 5 is a section on the line 5-5 in Figure 1; Figure 6 is a side elevation corresponding to Figure 1 of another embodiment of a toy crane; and Figure 7 is a section on the line 7-7 in Figure 6.

Referring now to Figures 1 to 5 of the drawings, one embodiment of a toy crane includes a base comprising a 4 fixed lower part 10 which is weighted to provide stability and an upper part 12 which carries a horizontal axis 14 and is rotateable relative to the lower part about a vertical axis 16. An arm 18 is pivotable at one end about the horizontal axis 14 and has fixed to it a first hand operated lever 20. A linkage which is pivotable relative to the arm 18 includes a first link 22 constrained to move parallel to the arm by a second link 24 pivotally interconnecting the arm 18 and that end of the first link 22 adjacent to the base, and by a pair of parallel third links 26. Said pair of third links is parallel to the second link 24, pivotally interconnects the arm 18 and the other end of the first link 22, and extends well beyond the arm. The arm 18 and the links 22, 24 and 26 together form a parallelogram linkage. A second hand-operated lever 28 consists of an extension of the second link 24 at that end remote from the arm 18 and is thus disposed adjacent to the first hand-operated lever 20. The linkage additionally includes a fourth link 30 which is pivotally connected at one end to a point on the arm 18 disposed further from the horizontal axis 14 than the point of pivotal connection between the arm and the pair of third links 26, and a pair of parallel fifth links 32 which is pivotally connected at one end to that end of the pair of third links 26 remote from the first link 22 and at an intermediate point to that end of the fourth link 30 remote from the arm 18. The arrangement is such that the pair of third links 26 and the fourth link 30 cross each other, the fourth link passing between the two third links. Load-carrying means in the form of a simple hook 34 are attached to that end of the fifth link 32 remote from the third link 26.

In operation, pivoting of the arm 18 about the horizontal axis 14 moves the hook 34 in a circle lying in a vertical plane and centred on said axis, and pivoting of the aforesaid linkage varies the radius of said circle and thus the reach of the hook. Additionally, rotation of the upper part 12 of the base about the vertical axis 16 causes the arm 18 and the aforesaid linkage, and with thein the hook 34, to rotate about said axis. Accordingly, the hook 34 is able to lift and position loads within a spherical spacial envelope which extends both above and below the base. The arm 18 is pivoted by manual operation of the lever 20 and the aforesaid linkage is pivoted by manual operation of the lever 28. Operation of the respective levers with two hands is easier, but due to said levers being disposed adjacent to each other it is quite feasible to operate them simultaneously with only one hand. Positioning of the hook 34 is carried out in a precise, smooth and accurate manner. Operating the toy crane develops manual skills and powers of co- ordination, which are particularly beneficial to children and can be remedial to the aged.

Referring now to Figures 6 and 7 of the drawings, another embodiment of a toy crane corresponds generally to 6 said one embodiment hereinbefore described, and like parts are designated by the same reference numerals. Said other embodiment does not employ a hand-operated lever 28 consisting of an extension of the second link 24. Instead, the second link 24 is arranged to interconnect pivotally that end of the first link 22 adjacent to the base 10, 12 ant that end of the arm 18 which is pivotable about the horizontal axis 14. As in said one embodiment, a hand operated lever 20 is fixed to the arm 18 for the purpose of pivoting said arm about the axis 14 to move the hook 34 in a circle lying in a vertical plane and centred on said axis. However, two hand-wheels 40 are fixed to the respective ends of a spindle 42 which is rotateable about the axis 14 and fixed to the second link 24 for the purpose of varying the radius of said circle and thus the reach of said hook. The spindle 42 and the arm 18 are of necessity relatively rotateable.

A simpler form of both illustrated embodiments of the invention omits the fourth link 30 and the pair of fifth links 32, the hook 34 being attached to that end of the pair of third links 26 remote from the first link 22 and thus having a reduced reach.

Various modifications are possible without departing from the scope of the invention, including the following:

The crane can be a full size machine capable of performing useful work, in which case pivoting of the upper 7 part of the base, the arm and aforesaid linkage is effected by means of respective geared electric motors.

The fourth link 30 can be pivotally connected at one end to a point on the arm 18 disposed nearer to the horizontal axis 14 than the point of pivotal connection between the arm and the pair of third links 26, the fifth links 32 are extended beyond their point of pivotal connection to the pair of third links in a direction away from the hook 34, and the fourth link is pivotally connected at its other end to that end of the extended pair of fifth links remote from the hook, so that the fourth link and the pair of third links still cross each other.

The second hand-operated lever can be fixed to any suitable part of the aforesaid linkage. It can for example consist of an extension of either one of the pair of third links at that end remote from the arm but, due to the first and second levers no longer being disposed adjacent to each other, simultaneous operation of said levers with only one hand will not be possible. 20 The vertical axis can be omitted, in which case the hook is only able to lift and position loads within a vertical circular plane which extends both above and below its base. The hook can be bifurcated as shown in Figures 2 and 3. Whereas a simple hook requires an eye, hook or the like on a load to be correctly orientated to permit engagement of the crane hook therewith, a bifurcated hook can pick up 8 a load having a protruding circular-headed lifting stud such as a screw head whatever its orientation and will also permit rotation of such a load whilst lifted.

The hook can be replaced by a magnet, which could be an electro-magnet.

The first link 22 can equally well be disposed at the other side of the arm 18, and pivotally connected thereat to the second link 24 and either the third links 26 or the fourth link 30 so as to form a parallelogram linkage.

9

Claims

Claims: -

1. A crane comprising a base, an arm which is pivotable at one end about a horizontal axis on the base, and a linkage which is pivotable relative to the arm and is provided with means for carrying a load, the arrangement being such that pivoting of the arm moves the means in a circle lying in a vertical plane and centred on the axis, and pivoting of the linkage varies the radius of said circle and thus the reach of the means.

2. A crane according to claim 1, wherein the base comprises a fixed lower part and an upper part which carries the horizontal axis and is rotateable relative to the lower part about a vertical axis, whereby the means can be rotated about the vertical axis.

3.A crane according to either of the preceding claims, wherein the linkage comprises a first link constrained to move parallel to the arm; a second link pivotally interconnecting the arm and that end of the first link adjacent to the base; and a third link parallel to the second link, pivotally interconnecting the arm and the other end of the first link, and extending beyond the arm.

4. A crane according to claim 3, wherein the linkage additionally comprises a fourth link pivotally connected at one end to a point on the arm spaced from the point of pivotal connection between the arm and the third link, and a fifth link pivotally connected at one end to that end of the third link remote from the first link and at an intermediate point to that end of the fourth link remote from the arm, the load-carrying means being attached to that end of the fifth link remote from the third link.

5. A crane according to claim 4, wherein the point of pivotal connection of the fourth link to the arm is disposed further from the horizontal axis than the point of pivotal connection between the arm and the third link, the arrangement being such that the third and fourth links cross each other.

6. A crane according to claim 4 or claim 5, wherein two parallel third links and two parallel fifth links are provided.

7. A crane according to claim 3, wherein the loadcarrying means are attached to that end of the third link remote from the first link.

8. A crane according to claim 1 or claim 2, comprising a toy wherein a first hand-operated lever is fixed to the arm and a second hand-operated lever is fixed to a suitable part of the linkage.

9. A crane according to any one of claims 3 to 7, comprising a toy wherein a first hand-operated lever is fixed to the arm and a second hand-operated lever consists of an extension of the second link at that end remote from the arm.

10. A crane according to claim 8 or claim 8, wherein the first and second hand-operated levers are disposed adjacent to each other so as to be capable of simultaneous operation with one hand.

11. A crane according to any one of claims 3 to 7, comprising a toy wherein the second link pivotally interconnects that end of the first link adjacent to the base and that end of the arm which is pivotable about the horizontal axis, a hand-operated lever being fixed to the arm and at least one hand-wheel being fixed to a spindle which is rotateable about said axis and fixed to the second link.

12. A crane constructed, arranged and adapted to operate substantially as hereinbefore described.

13. A crane comprising a toy, constructed, arranged and adapted to operate substantially as hereinbefore described with reference to, and as illustrated by, Figures 1 to 5 of the accompanying drawings.

14. A crane comprising a toy, constructed, arranged and adapted to operate substantially as hereinbefore described with reference to, and as illustrated by, Figures 6 and 7 of the accompanying drawings.