CA1098489A - Low-profile crane without topping tower - Google Patents
Low-profile crane without topping towerInfo
- Publication number
- CA1098489A CA1098489A CA325,287A CA325287A CA1098489A CA 1098489 A CA1098489 A CA 1098489A CA 325287 A CA325287 A CA 325287A CA 1098489 A CA1098489 A CA 1098489A
- Authority
- CA
- Canada
- Prior art keywords
- jib
- pulley means
- pulley
- topping
- crane
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
- B66C23/00—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes
- B66C23/06—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes with jibs mounted for jibbing or luffing movements
- B66C23/08—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes with jibs mounted for jibbing or luffing movements and adapted to move the loads in predetermined paths
- B66C23/10—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes with jibs mounted for jibbing or luffing movements and adapted to move the loads in predetermined paths the paths being substantially horizontal; Level-luffing jib-cranes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
- B66C23/00—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes
- B66C23/62—Constructional features or details
- B66C23/82—Luffing gear
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Jib Cranes (AREA)
Abstract
ABSTRACT
A Low-Profile Crane without Topping Tower A hoisting line (9) extends from a winch (8), over a second pulley (12) at the head end (3) of the jib (1) of a crane, around a movable pulley (14) and over a third pulley (13) at the head end (3) of the jib (1) to a depending load hook (18).
The movable pulley (14) is supported by a topping line (7) which extends over a first pulley (11) at the tail end (2) of the jib (1), around a fifth pulley (15) fix-edly mounted on the base (4) of the crane and is attached to the first pulley (11).
Loading in the hoisting line (9) is therefore transferred to the topping line (7) extending between the first and fifth pulleys (11 and 15) and topping of the jib (1) about an axis (5) between the tail and head ends (2 and 3) is effected by a light-weight piston-cylinder assembly (6).
A Low-Profile Crane without Topping Tower A hoisting line (9) extends from a winch (8), over a second pulley (12) at the head end (3) of the jib (1) of a crane, around a movable pulley (14) and over a third pulley (13) at the head end (3) of the jib (1) to a depending load hook (18).
The movable pulley (14) is supported by a topping line (7) which extends over a first pulley (11) at the tail end (2) of the jib (1), around a fifth pulley (15) fix-edly mounted on the base (4) of the crane and is attached to the first pulley (11).
Loading in the hoisting line (9) is therefore transferred to the topping line (7) extending between the first and fifth pulleys (11 and 15) and topping of the jib (1) about an axis (5) between the tail and head ends (2 and 3) is effected by a light-weight piston-cylinder assembly (6).
Description
1~8489 TECHNICAL FIELD OF THE INVENTION
The invention relates to a crane in which topping is effected by coupling the topping rigging to the hoisting rigging in such a way that no topping tower or mast is required, to provide a compact, low-profile crane.
BACKGROUND ART
In conventional deck crane construction, the topping rigging extends from a topping tower or mast to the head end of the jib and is controlled independently of the hoisting rigging by means of a topping winch. However, in some applications, for example on board ships, the necessary weight and overall height of a crane provided with a topping tower or mast has disadvantages and so alternative means, such as a fluid-operated piston-cylinder assembly,must be provided to effect topping of the jib. However, this necessitates the use of a very heavy-duty piston-cylinder assembly and the jib and its mounting must be constructed with corresponding robustness.
This not not only increases the cost of the crane, but sub-stantially reduces any saving in weight achieved by the omission of the topping tower or mast.
One way of overcoming this difficulty is disclosed in French Patent Specification No. 403 847 and corresponding British Patent Specification No. 18863 of 1908 which describe a crane with a jib having a rearward extension from its horizontal pivotal axis. A hoisting line depending from a pulley at the head end of the jib is also trained around pulleys respectively mounted on this rearward extension and on a rotatable support for the jib. This ensures that turning moments imposed on the jib by the load are substantially balanced by turning moments imposed on the jib by the tension in the hoisting line extending between the pulleys mounted on the rearward extension of the jib and on the rotatable support ~"8489 for the jib. Moreoverr these specifications also disclose the use of a piston-cylinder assembly for pivoting the jib about the horizontal pivotal axis. However, in this form of construction, the hoisting line must be trained around all the compensating pulleys mounted on the rearward extension of the jib and on the rotatable support for the jib and this imposes considerable additional loading on the hoisting winch.
One way of overcoming this difficulty is disclosed in British Patent Specification No. 264 769 which describes a crane comprising a jib having a tail end and a head end; mount-ing means for supporting the jib for pivotal movement about a horizontal axis extending transversely of the jib; luffing means extendin~ between the jib and the mounting means for pivoting the jib about the horizontal axis; first pulley means mounted on the tail end of the jib, third pulley means mounted on the head end of the jib, and fourth pulley means movable between the tail end of the jib and the head end of the jib;
at least one topping line extending around the first pulley means and having one end connected to the fourth pulley means and the other end extending between the first pulley means and the mounting means; a hoisting winch; and a hoisting line extend-ing from the hoisting winch and around the fourth and third and pulley means to depend from the head end of the jib.
By this means, an attempt is made to balance the turn-ing moments imposed on the jib by the topping line and the hoisting line without imposing any undue loading on the hoist-ing line. However, it is virtually impossible to provide the balance required because of the variation in the turning moment resulting from the tension in the hoisting line extend-ing from the hoisting winch to the fourth pulley means becauseof the movement of the fourth pulley means relative to the pivotal axis.
1~)"8489 DISCLOS~RE OF THE INVENTION
It is an object of the present invention to provide a crane which does not require a topping tower or mast for the topping rigging but which is substantially lighter and more economical to construct than known cranes provided with fluid-operated, piston-cylinder assemblies for topping the jib.
This object is achieved by providing a crane similar to that disclosed in British Patent Specification No. 264,7~9 but in which second pulley means are mounted at the,head end of the jib and and the hoisting line extends from the hoisting winch and around the second pulley means to the fourth and third pulley means; and the hoisting line extends from the hoisting winch to the second pulley means along a line which remains substantially aligned with a line extending from the horizontal axis to the second pulley means.
In a crane such as this, where the hoisting rigging is coupled to the topping rigging by means of the fourth pulley means, the turning moment exerted on the jib by a load suspended from the depending end of the hoisting line is counteracted by the moment exerted by the topping rigging ex-tending between the first and fifth pulley means. It is til~r~for~ possibl~ to effect toppiIIg by means of a relativelv lignt-duty pis~on~cylinder assembly~ Thus, when it is re~uired to lift a load, the hoisting winch subjects the hoisting line to tension and this tension is transferred il~tO tne topping rigging by means of the fourth pulley means coupling the hoist-ing and topping ~,.
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- 2a -, , ; . : , `` 10C~8489 riggings. The fourth pulley means therefore tend to move towards the head end of the jib so that the topping rigg-ing tends to pull the first pulley means down to the fixed fifth pulley means, thus tending to raise the jib. In this case, it is often necessary to use the piston-cylin-der assembly to prevent the jib from topping until the hoisting line has been sufficiently shortened. Thereafter, topping of the jib can be effected merely by releasing the piston-cylinder assembly or by applying a very small lift-ing force by means of the piston-cylinder assembly.
Similar considerations apply when lowering a load and so has been found that effective topping control can be effected with a relatively light-duty piston-cylinder assembly. Moreover, as a result of the coupling of the hoisting and topping riggings, substantially level luff-ing may also be achieved.
Clearly, to maintain static equiblibrium when a load is supported from the head end of the jib, the mounting means must be prevented from tilting and, for this purpose, it is convenient to use a counter-weight which is supported on the mounting means on the opposite side of the hori-zontal pivotal axis of the jib to the load. However, the components of the crane may be constructed so that this counter-weight is not excessive and the total weight of the crane is less than an equivalent crane provided with a topping tower or mast.
To increase the loading transmitted from the hoisting line to the topping rigging, the second and fourth pulley means may each be provided with a plurality of pulleys so that there is a two or more part purchase between these two pulley means. However, even where the second and fourth pulley means are each only provided with one pulley, the loading transmitted from the hoisting line to the topping rigging is twice the weight of the load.
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1~98489 Where a plurality of topping lines are used, it is possible to ensure that the loading on each such topping line does not exceed the loading on the hoisting line by ensuring that the number of topping lines equals the number of lengths of the hoisting line extending from the fourth pulley means to the second and third pulley means. In this case, the third and fifth pulley means must also each contain the pulleys for each of the topping lines.
To ensure that the crane operates in a predictable manner, particularly where more than one topping line is employed, the fourth pulley means may be mounted for movement along guide means which extend along a rectilinear axis between the first pulley means at the tail end of the jib and the second and third pulley means at the head end of the jib.
To avoid jack-knifing, or uncontrolled lifting of the jib, as a result of tensile loading on the hoisting line, the first pulley means and the fifth pulley means may be dis-posed at different distances from the horizontal pivotal axis so that the axis of the first pulley means is movable into an end position alongside the fifth pulley means on a radial plane containing the horizontal pivotal axis and the axis of the fifth pulley means. In this situation the topping line extending between corresponding pulleys in the first and fi~th pulley means are substantially aligned with the radial plane and so, as the first pulley means move into this position, the turning moment imposed on the jib by each said topping line progressively decreases to zero. In fact, elevation of the jib beyond this inclina-tion results in the imposition of a restoring force in each said topping line which urges the jib to pivot in the opposite direction.
BRIEF DESCRIPTION OF THE DRAWINGS
Two embodiments of the invention are hereinafter described, , . ~
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by way of example, with reference to the accompanying drawings, in which:-Figure 1 is a schematic view of a preferred embodiment ofthe invention, showing a jib and its mounting means in phantom outline;
Figure 2 is a view of the hoisting and topping riggings of the crane shown in Figure 1;
Figure 3 is a schematic view of the hoisting and topping riggings of an alternative form of crane; and Figure 4 is a schematic view of the riggings shown in Figure 3, when the crane is topped.
BEST MODES FOR CARRYING OUT THE INVENTION
The crane shown in Figure 1 has a jib 1 formed of two triangular frames 16 which are held together by cross braces 17 so as to converge towards the head end 3 of the jib i. First pulley means in the form of two pulleys li are mounted at the tail end 2 of the jib 1, adjacent one of the apices of each Or the triangular frames 16. Second and third pulleys 12 and 13 are mounted at the head end 3 of the jib 1, adjacent another of the apices of each of the triangular frames 1~. A hoisting line 9 extends from a hoisting winch 8 supported on a mounting platform 4 and is trained around the second pulley 12, around a fourth pulley 14, between the tail and head ends 2 and 3 of the jib 1~ and over the third pulley 13 to a depending load hook 18. The mounting platform 4 also supports a shaft 5 which in turn supports the jib 1 for pivotal movement about a horizontal axis extending transversely of the jib 1 and coinciding with the third of the apices of each of the triangular frames 16. The mounting platform 4 also supports fifth pulley means, in the form of two ~g8489 pulleys 15 which are arranged below the pulleys 11 of the first pulley means at the tail end 2 of the jib 1. Opp-osite ends of the two topping lines 7 are respectively attached to one of the pulleys 11 and to one arm of a yoke 19 supporting the fourth pulley 14 and the two topp-ing lines are trained around the first and fifth pulleys 11 and 15.
The mounting platform 4 is mounted above a fixed ring gear 20 and provided with a pinion 21 meshing with the ring gear 20. A motor 22 carried by the mounting plat-form 4 is operable to drive the pinion 21 to thereby cause a rotation of the mounting platform 4 about a ver-tically extending axis 23 through the centre of the ring gear 20. Part 24 of the mounting platform 4 serves as a counter-weight for at least partly balancing loads carr-ied by the load hook 8.
The upper members 10 of the two triangular frames 16 serve as rectilinear guides for the yokel9 connecting the two topping lines 7 to the fourth pulley 14 so as to allow the fourth pulley 14 to move backwards and forwards along a rectilinear path between the two pulleys 11 of the first pulley means at the tail end 2 o~ the jib 1 and the second and third pulleys 12 and 13 at the head end 3 of the jib 1. A light-weight hydraulic piston-cylinder 6 extends from the jib 1 to the mounting platform 4.
As shown in Figure 2, when the hoisting line 9 supports a load L there is an anti-clockwise turning moment of L.x, where x is the horizontal distance between the load hook 18 ard the axis of the shaft 5. However, as shown, a loading of L is transmitted from the hoisting line 9 to each of the topping lines 7 through the fourth pulley 14 and, as the horizontal distance between the axis of the shaft 5 and the line of action of the topping lines 7 `. :
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~8~89 extending betwesn the first and fifth pulleys 11 and 15 is approximately y, the clockwise turning moment resist-ing the load L is approximately 4L.y. The force there-fore required to be exerted by the hydraulic piston-- 5 cylinder assembly 6 is thus the difference between value of these clockwise and anti-clockwise turning moments and so topping can be effected with very little effort. In the alternative arrangement of the crane, shown in Figure 3, there is only one topping line 7 and a load L suppor-ted by the load hook 18 induces a tension of 2L in this single topping line 7. In this case, the topping line 7 must be capable of withstanding twice the loading in the hoisting line 9.
~learly, from reference to both illustrated embodiments, it is advantageous if the.hoisting line 9 extending from the hoisting winch 8 to the second pulley 12 passes through or close to the axis of the shaft 5 so as to en-sure that the clockwise turning moment exerted by the topping line of lines 7 is not substantially counteracted 20 by the tension in the hoisting cable 9 extending between 1.
the jib 1 and the hoist 8.
As shown in Figure 3, the centre distance 24 between the shaft 5 and the first pulley 11 is greater than the cen-tre distance 25 between the shaft 5 and the fifth pulley 15. Thus, when the jib 1 is elevated, as shown.in Figure 4, the first pulley 11 moves to an end position.along-side the fifth pulley 15 such that the axes of the first and fifth pulleys (lland 15) lie on a radial plane 26 containing the axis of the shaft 5. On further upward tilting movement of the jib 1, the tensile loading in the topping line 5 urges the jib to return to the posi-ti.on it occupies for the arrangement shown in Figure 4.
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The invention relates to a crane in which topping is effected by coupling the topping rigging to the hoisting rigging in such a way that no topping tower or mast is required, to provide a compact, low-profile crane.
BACKGROUND ART
In conventional deck crane construction, the topping rigging extends from a topping tower or mast to the head end of the jib and is controlled independently of the hoisting rigging by means of a topping winch. However, in some applications, for example on board ships, the necessary weight and overall height of a crane provided with a topping tower or mast has disadvantages and so alternative means, such as a fluid-operated piston-cylinder assembly,must be provided to effect topping of the jib. However, this necessitates the use of a very heavy-duty piston-cylinder assembly and the jib and its mounting must be constructed with corresponding robustness.
This not not only increases the cost of the crane, but sub-stantially reduces any saving in weight achieved by the omission of the topping tower or mast.
One way of overcoming this difficulty is disclosed in French Patent Specification No. 403 847 and corresponding British Patent Specification No. 18863 of 1908 which describe a crane with a jib having a rearward extension from its horizontal pivotal axis. A hoisting line depending from a pulley at the head end of the jib is also trained around pulleys respectively mounted on this rearward extension and on a rotatable support for the jib. This ensures that turning moments imposed on the jib by the load are substantially balanced by turning moments imposed on the jib by the tension in the hoisting line extending between the pulleys mounted on the rearward extension of the jib and on the rotatable support ~"8489 for the jib. Moreoverr these specifications also disclose the use of a piston-cylinder assembly for pivoting the jib about the horizontal pivotal axis. However, in this form of construction, the hoisting line must be trained around all the compensating pulleys mounted on the rearward extension of the jib and on the rotatable support for the jib and this imposes considerable additional loading on the hoisting winch.
One way of overcoming this difficulty is disclosed in British Patent Specification No. 264 769 which describes a crane comprising a jib having a tail end and a head end; mount-ing means for supporting the jib for pivotal movement about a horizontal axis extending transversely of the jib; luffing means extendin~ between the jib and the mounting means for pivoting the jib about the horizontal axis; first pulley means mounted on the tail end of the jib, third pulley means mounted on the head end of the jib, and fourth pulley means movable between the tail end of the jib and the head end of the jib;
at least one topping line extending around the first pulley means and having one end connected to the fourth pulley means and the other end extending between the first pulley means and the mounting means; a hoisting winch; and a hoisting line extend-ing from the hoisting winch and around the fourth and third and pulley means to depend from the head end of the jib.
By this means, an attempt is made to balance the turn-ing moments imposed on the jib by the topping line and the hoisting line without imposing any undue loading on the hoist-ing line. However, it is virtually impossible to provide the balance required because of the variation in the turning moment resulting from the tension in the hoisting line extend-ing from the hoisting winch to the fourth pulley means becauseof the movement of the fourth pulley means relative to the pivotal axis.
1~)"8489 DISCLOS~RE OF THE INVENTION
It is an object of the present invention to provide a crane which does not require a topping tower or mast for the topping rigging but which is substantially lighter and more economical to construct than known cranes provided with fluid-operated, piston-cylinder assemblies for topping the jib.
This object is achieved by providing a crane similar to that disclosed in British Patent Specification No. 264,7~9 but in which second pulley means are mounted at the,head end of the jib and and the hoisting line extends from the hoisting winch and around the second pulley means to the fourth and third pulley means; and the hoisting line extends from the hoisting winch to the second pulley means along a line which remains substantially aligned with a line extending from the horizontal axis to the second pulley means.
In a crane such as this, where the hoisting rigging is coupled to the topping rigging by means of the fourth pulley means, the turning moment exerted on the jib by a load suspended from the depending end of the hoisting line is counteracted by the moment exerted by the topping rigging ex-tending between the first and fifth pulley means. It is til~r~for~ possibl~ to effect toppiIIg by means of a relativelv lignt-duty pis~on~cylinder assembly~ Thus, when it is re~uired to lift a load, the hoisting winch subjects the hoisting line to tension and this tension is transferred il~tO tne topping rigging by means of the fourth pulley means coupling the hoist-ing and topping ~,.
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- 2a -, , ; . : , `` 10C~8489 riggings. The fourth pulley means therefore tend to move towards the head end of the jib so that the topping rigg-ing tends to pull the first pulley means down to the fixed fifth pulley means, thus tending to raise the jib. In this case, it is often necessary to use the piston-cylin-der assembly to prevent the jib from topping until the hoisting line has been sufficiently shortened. Thereafter, topping of the jib can be effected merely by releasing the piston-cylinder assembly or by applying a very small lift-ing force by means of the piston-cylinder assembly.
Similar considerations apply when lowering a load and so has been found that effective topping control can be effected with a relatively light-duty piston-cylinder assembly. Moreover, as a result of the coupling of the hoisting and topping riggings, substantially level luff-ing may also be achieved.
Clearly, to maintain static equiblibrium when a load is supported from the head end of the jib, the mounting means must be prevented from tilting and, for this purpose, it is convenient to use a counter-weight which is supported on the mounting means on the opposite side of the hori-zontal pivotal axis of the jib to the load. However, the components of the crane may be constructed so that this counter-weight is not excessive and the total weight of the crane is less than an equivalent crane provided with a topping tower or mast.
To increase the loading transmitted from the hoisting line to the topping rigging, the second and fourth pulley means may each be provided with a plurality of pulleys so that there is a two or more part purchase between these two pulley means. However, even where the second and fourth pulley means are each only provided with one pulley, the loading transmitted from the hoisting line to the topping rigging is twice the weight of the load.
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1~98489 Where a plurality of topping lines are used, it is possible to ensure that the loading on each such topping line does not exceed the loading on the hoisting line by ensuring that the number of topping lines equals the number of lengths of the hoisting line extending from the fourth pulley means to the second and third pulley means. In this case, the third and fifth pulley means must also each contain the pulleys for each of the topping lines.
To ensure that the crane operates in a predictable manner, particularly where more than one topping line is employed, the fourth pulley means may be mounted for movement along guide means which extend along a rectilinear axis between the first pulley means at the tail end of the jib and the second and third pulley means at the head end of the jib.
To avoid jack-knifing, or uncontrolled lifting of the jib, as a result of tensile loading on the hoisting line, the first pulley means and the fifth pulley means may be dis-posed at different distances from the horizontal pivotal axis so that the axis of the first pulley means is movable into an end position alongside the fifth pulley means on a radial plane containing the horizontal pivotal axis and the axis of the fifth pulley means. In this situation the topping line extending between corresponding pulleys in the first and fi~th pulley means are substantially aligned with the radial plane and so, as the first pulley means move into this position, the turning moment imposed on the jib by each said topping line progressively decreases to zero. In fact, elevation of the jib beyond this inclina-tion results in the imposition of a restoring force in each said topping line which urges the jib to pivot in the opposite direction.
BRIEF DESCRIPTION OF THE DRAWINGS
Two embodiments of the invention are hereinafter described, , . ~
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by way of example, with reference to the accompanying drawings, in which:-Figure 1 is a schematic view of a preferred embodiment ofthe invention, showing a jib and its mounting means in phantom outline;
Figure 2 is a view of the hoisting and topping riggings of the crane shown in Figure 1;
Figure 3 is a schematic view of the hoisting and topping riggings of an alternative form of crane; and Figure 4 is a schematic view of the riggings shown in Figure 3, when the crane is topped.
BEST MODES FOR CARRYING OUT THE INVENTION
The crane shown in Figure 1 has a jib 1 formed of two triangular frames 16 which are held together by cross braces 17 so as to converge towards the head end 3 of the jib i. First pulley means in the form of two pulleys li are mounted at the tail end 2 of the jib 1, adjacent one of the apices of each Or the triangular frames 16. Second and third pulleys 12 and 13 are mounted at the head end 3 of the jib 1, adjacent another of the apices of each of the triangular frames 1~. A hoisting line 9 extends from a hoisting winch 8 supported on a mounting platform 4 and is trained around the second pulley 12, around a fourth pulley 14, between the tail and head ends 2 and 3 of the jib 1~ and over the third pulley 13 to a depending load hook 18. The mounting platform 4 also supports a shaft 5 which in turn supports the jib 1 for pivotal movement about a horizontal axis extending transversely of the jib 1 and coinciding with the third of the apices of each of the triangular frames 16. The mounting platform 4 also supports fifth pulley means, in the form of two ~g8489 pulleys 15 which are arranged below the pulleys 11 of the first pulley means at the tail end 2 of the jib 1. Opp-osite ends of the two topping lines 7 are respectively attached to one of the pulleys 11 and to one arm of a yoke 19 supporting the fourth pulley 14 and the two topp-ing lines are trained around the first and fifth pulleys 11 and 15.
The mounting platform 4 is mounted above a fixed ring gear 20 and provided with a pinion 21 meshing with the ring gear 20. A motor 22 carried by the mounting plat-form 4 is operable to drive the pinion 21 to thereby cause a rotation of the mounting platform 4 about a ver-tically extending axis 23 through the centre of the ring gear 20. Part 24 of the mounting platform 4 serves as a counter-weight for at least partly balancing loads carr-ied by the load hook 8.
The upper members 10 of the two triangular frames 16 serve as rectilinear guides for the yokel9 connecting the two topping lines 7 to the fourth pulley 14 so as to allow the fourth pulley 14 to move backwards and forwards along a rectilinear path between the two pulleys 11 of the first pulley means at the tail end 2 o~ the jib 1 and the second and third pulleys 12 and 13 at the head end 3 of the jib 1. A light-weight hydraulic piston-cylinder 6 extends from the jib 1 to the mounting platform 4.
As shown in Figure 2, when the hoisting line 9 supports a load L there is an anti-clockwise turning moment of L.x, where x is the horizontal distance between the load hook 18 ard the axis of the shaft 5. However, as shown, a loading of L is transmitted from the hoisting line 9 to each of the topping lines 7 through the fourth pulley 14 and, as the horizontal distance between the axis of the shaft 5 and the line of action of the topping lines 7 `. :
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~8~89 extending betwesn the first and fifth pulleys 11 and 15 is approximately y, the clockwise turning moment resist-ing the load L is approximately 4L.y. The force there-fore required to be exerted by the hydraulic piston-- 5 cylinder assembly 6 is thus the difference between value of these clockwise and anti-clockwise turning moments and so topping can be effected with very little effort. In the alternative arrangement of the crane, shown in Figure 3, there is only one topping line 7 and a load L suppor-ted by the load hook 18 induces a tension of 2L in this single topping line 7. In this case, the topping line 7 must be capable of withstanding twice the loading in the hoisting line 9.
~learly, from reference to both illustrated embodiments, it is advantageous if the.hoisting line 9 extending from the hoisting winch 8 to the second pulley 12 passes through or close to the axis of the shaft 5 so as to en-sure that the clockwise turning moment exerted by the topping line of lines 7 is not substantially counteracted 20 by the tension in the hoisting cable 9 extending between 1.
the jib 1 and the hoist 8.
As shown in Figure 3, the centre distance 24 between the shaft 5 and the first pulley 11 is greater than the cen-tre distance 25 between the shaft 5 and the fifth pulley 15. Thus, when the jib 1 is elevated, as shown.in Figure 4, the first pulley 11 moves to an end position.along-side the fifth pulley 15 such that the axes of the first and fifth pulleys (lland 15) lie on a radial plane 26 containing the axis of the shaft 5. On further upward tilting movement of the jib 1, the tensile loading in the topping line 5 urges the jib to return to the posi-ti.on it occupies for the arrangement shown in Figure 4.
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Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A crane comprising a jib having a tail end and a head end mounting means for supporting the jib for pivotal movement about a horizontal axis extending transversely of the jib; luffing means extending between the jib and the mounting means for pivoting the jib about the horizontal axis; first pulley means mounted on the tail end of the jib, third pulley means mounted on the head end of the jib, and fourth pulley means movable between the tail end of the jib and the head end of the jib; at least one topping line extending around the first pulley means and having one end connected to the fourth pulley means and the other end extending between the first pulley means and the mounting means; a hoisting winch; and a hoisting line extending from the hoisting winch and around the fourth and third pulley means to depend from the head end of the jib characterized in that second pulley means are mounted at the head end of the jib and the hoisting line extends from the hoisting winch and around the second pulley means to the fourth and third pulley means; and the hoisting line extends from the hoisting winch to the second pulley means along a line which remains substantially aligned with a line extending from the horizontal axis to the second pulley means.
2. A crane, according to claim 1, characterized in that fifth pulley means are fixedly mounted on the mounting means below the first pulley means at the tail end of the jib and said other end of each topping line includes at least two reaches extending between the first and fifth pulley means and is attached to the tail end of the jib or to the mounting means.
3. A crane, according to claim 2, characterized in that the number of topping lines equals the number of lengths of the hoisting line extending from the fourth pulley means to the second and third pulley means and the first and fifth pulley means contain pulleys for each of the topping lines so that the topping lines are each subjected to the same loading as the hoisting line.
4. A crane, according to claim 1, 2 or 3, characterized in that the first, second, third and fourth pulley means are supported so that the or each topping line acts on the fourth pulley means along an axis which is disposed above the horizontal pivotal axis of the jib.
5. A crane, according to claim 1, 2 or 3, characterized in that guide means for the fourth pulley means extends along a rectilinear axis between the first pulley means at the tail end of the jib and the second and third pulley means at the head end of the jib.
6. A crane, according to claim 1, 2 or 3, character-ized in that the first pulley means and the fifth pulley means are disposed at different distances from the horizontal pivotal axis so that the first pulley means are movable into an end position alongside the fifth pulley means so that the horizon-tal pivotal axis and the axes of the first and fifth pulley means lie in the same plane.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB14220/78 | 1978-04-11 | ||
| GB1422078 | 1978-04-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1098489A true CA1098489A (en) | 1981-03-31 |
Family
ID=10037220
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA325,287A Expired CA1098489A (en) | 1978-04-11 | 1979-04-10 | Low-profile crane without topping tower |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0016761A1 (en) |
| JP (1) | JPS55500460A (en) |
| CA (1) | CA1098489A (en) |
| NL (1) | NL7902596A (en) |
| WO (1) | WO1979000915A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6503344B2 (en) | 1999-02-05 | 2003-01-07 | Houghton Durferrit Gmbh | Boronizing agent in paste form |
| CN102979079B (en) * | 2012-11-22 | 2014-04-16 | 三一重工股份有限公司 | Cylinder driven derricking mechanism of dynamic compaction machine and dynamic compaction machine |
| CN112110342A (en) * | 2020-10-16 | 2020-12-22 | 三一海洋重工有限公司 | Crane with a movable crane |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR403847A (en) * | 1908-09-08 | 1909-11-15 | Societe R. Waygood & C° Limited | Improvements to cranes and similar lifting devices |
| GB206407A (en) * | 1923-01-13 | 1923-11-08 | Cowans Sheldon & Co Ltd | Improvements in jib cranes |
| GB270856A (en) * | 1926-03-11 | 1927-05-19 | Thomas Souness | Improvements in luffing cranes |
| GB264769A (en) * | 1926-10-26 | 1927-01-27 | Eisenwerk Vorm Nagel & Kaemp A | Improvements in cranes |
| FR625505A (en) * | 1926-11-23 | 1927-08-12 | Le Titan Anversois | Lifting device for crane boom |
| FR634511A (en) * | 1927-05-17 | 1928-02-20 | Caillard & Cie Ets | Improvements to variable reach cranes |
| DE599401C (en) * | 1932-03-04 | 1934-06-30 | Orenstein & Koppel Akt Ges | Load rope compensation device for adjustable arms |
| FR760662A (en) * | 1933-09-11 | 1934-02-28 | Venot Et Cie Soc | Improvements to variable reach cranes |
| FR1126222A (en) * | 1954-06-19 | 1956-11-19 | Maschf Augsburg Nuernberg Ag | Building crane with variable reach boom and wire rope lifting mechanism including hoist |
-
1979
- 1979-03-30 JP JP50053479A patent/JPS55500460A/ja active Pending
- 1979-03-30 WO PCT/GB1979/000054 patent/WO1979000915A1/en unknown
- 1979-04-03 NL NL7902596A patent/NL7902596A/en not_active Application Discontinuation
- 1979-04-10 CA CA325,287A patent/CA1098489A/en not_active Expired
- 1979-11-19 EP EP19790900302 patent/EP0016761A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| EP0016761A1 (en) | 1980-10-15 |
| JPS55500460A (en) | 1980-07-31 |
| WO1979000915A1 (en) | 1979-11-15 |
| NL7902596A (en) | 1979-10-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |