US3300061A

US3300061A - Mast

Info

Publication number: US3300061A
Application number: US473461A
Authority: US
Inventors: Joseph C Bamford
Original assignee: JC Bamford Excavators Ltd
Current assignee: JC Bamford Excavators Ltd
Priority date: 1964-07-23
Filing date: 1965-07-20
Publication date: 1967-01-24
Anticipated expiration: 1984-01-24
Also published as: IL23997A

Description

Jan. 24, 1967 J. C. BAMFoRb MAST E Sheets-Sheet l Filed July 20, 1965 Car-WM Jan. 24, 1967 J. c. BAMFORD MAST 3 Sheets-Sheet 2 Filed July 20, 1965 Asem' Jan. 24, 1967 1. c. BAMFoRD 3,300,051

MAST

Filed July 20, 1965 5 Sheets-SheetI 5 WWW HGEMT United States Patent O 3,300,061 MAST Joseph C. Bamford, Uttoxeter, England, assignor to J. C. Bamford (Excavators) Limited, Lakeside, Rocester, England, a British company Filed July 20, 1965, Ser. No. 473,461 Claims priority, application Great Britain, July 23, 1964, 29,637 64 2 Claims. (Cl. 212-144) This invention relates to masts and has for its main object to vprovide a new or improved f-orm of mast which can be collapsed and stowed when not in use.

With this main object in view, according to the invention we provide a mast comprising two or more tubular sections which are telescopically .arranged one within another, the or each section above the lowermost being fitted as a piston in the section next below and means being provided for supplying air under pressure to the interior of the mast and releasable locking means being provided between the or each pair of sections to hold the sections in their extended relative positions.

In order to provide for collapsing for storage or transport, the lowermost section of the mast may be pivotally mounted about a horizontal axis upon a base member so that the mast may be pivoted about said axis to lie in a horizontal or substantially horizontal plane with all the other sections telescoped therein.

Preferab1y,'a boom is connected to the uppermost section to project transversely therefrom when the mast is extended.

To withstand the heavy load imposed on the mast when lifting heavy weights the locking means provided must be strong and preferably the locking means between the or each pair of sections comprises a plurality of locking elements spaced apart around the annular space between the or each pair of telescoped sections and each locking element comprises a locking plate, secured to the exterior of the inner section of the or each pair of sections, and having a recess extending substantially tangentially to said inner section from a vertical edge of said locking plate, and a locking piece slidably mounted on the outer section of the or each pair of sections for angular movement about the vertical axis of the mast from a disengaged position to an engaged position in which the locking piece engages with said recess to prevent vertical displacement of the sections relative to each other.

Preferably each locking piece projects outwardly through a slot formed in said outer section and each l-ocking piece is secured to a band member which extends around the periphery of the said outer section, whereby movement of all said locking pieces from their disengaged position to their engaged position is achieved simultaneously.

The above described arrangement may be made portable by mounting the base member upon a suitable vehicle and the base member may incorporate slewing means for rotating the mast, When extended, about a vertical axis to traverse the boom, or alternatively, the traversing of the boom may be provided by arranging a slewing ring on the uppermost section, the boom being connected to this ring for rotation about a vertical axis.

The mast according to the present invention may be used in a variety of applications such as a portable television or radio mast and is especially suitable for a portable crane.

A crane ernbodying the present invention will now be described in more detail by way of example with reference to the accompanying drawings, it being appreciated that the scope of the invention is not limited to certain specific details mentioned hereinafter.

ICC

FIGURE 1 is a side elevation of a crane embodying the present invention, mounted on a railway bogey and in its extended position,

FIGURE 2 is a part section, to an enlarged Scale, on the centre line of FIGURE 1, showing the telescoped ends of the lower and intermediate sections,

FIGURE 3 is a part sectional plan view on the line 3- 3 in FIGURE 2, and,

FIGURE 4 is a side elevation of another example of a crane embodying the present invention, mounted on a lorry and in its stored position.

In this arrangement the mast, which is indicated generally at 10 in FIGURE 1, comprises three sections, there being a lowermost section 11, an intermediate section 12 and an upper section 14 each made from steel tubes and of appropriate diameters so that the intermediate section 12 is telescopically slidable within the lowermost section 11 and the uppermost section 14 is telescopically slidable within lthe intermediate section 12.

The external diameter of the intermediate section 12 is such as to provide an annular clearance 20 (see FIG- URE 2) between its wall and the interior of the lowermost section 11 and a similar arrangement operates for providing an annular clearance between the uppermost section 14 and the interior wall of the intermediate section 12 and each of the intermediate and

uppermost sections

12 and 14 respectively has its

lower end

15 and 16 respectively fitted with an annular ring (which is shown at 18 in FIGURE 2 in the case of the intermediate section 12) the external'diameter of which is such that it slidably engages the interior wall of the section within which it slides and the underside of this ring is fitted with an annular Sealing ring (which is shown at 19 in the case of the intermediate section 12) of suitable material such as neoprene to form an air-tight seal with the interior wall of the section in which it slides.

Thus the uppermost and

intermediate sections

14 and 12 respectively have sliding engagement as pistons within the interior of the intermediate and lowermost sections 12 and 11 respectively and the top end 17 of the uppermost section 14 is completely closed so that when compressed air is introduced into the interior of the mast 10 when in its collapsed position, the intermediate and

uppermost section

12 and 14 respectively will be elevated ydue to the air pressure so as to extend the mast 10 to its full height.

It is necessary to provide suitable locking means 'between each pair of sections when in the fully extended position to lock the sections rigidly together for operation of the crane and the following is a description of a preferred locking mechanism for locking the sections together. The locking means employed must be strong in order to withstand the heavy loads imposed when lifting heavy weights. Such locking means is employed between the uppermost and intermediate sections, and the intermediate and lowermost sections. For convenience of description only the locking means between the intermediate section 12 and the lowermost section 11 will be described and it should be understood that the locking means between the uppermost section 14 and the intermediate section 11 are identical.

Referring to FIGURES 2 and 3, in the annular space 20 between the intermediate section 12, which is the inner section and the lower section 11, which is the outer section, the ,inner section 12 has secured to its exterior, a number of locking elements, indicated generally at 21, each of which comprises a plate 22 of rectangular form arranged with its major axis vertical and having a recess 23 extending inwardly from one of the longer side edges of the plate and these locking elements 21 are secured to the exterior of the inner section 12 at spaced apart positions around the circumference.

The outer section 11 at a position near its upper end, has a number -of slots 24 in its wall, these slots 24 corresponding in number to the plates 22 on the inner section 12 and being spaced apart circumferentially. A locking piece 25 is slidably mounted in each slot 24 so as to be capable of an angular movement about the vertical axis of the mast from a disengaged position to an engaged locking position as shown in FIGURE 3. 1

All the locking pieces 25 project through the slots an are secured to a common circular 'band 26 which extends around the whole of the periphery of the outer section 11, this band 26 being capable of being fixed in either of two positions by means of a peg 27 passing through a hole 36 in a lug 28 projecting radially from the band, such peg 27 being engageable in either one of two holes 30 and 31 spaced apart in a bracket 29 secured to the exterior of the outer section 11.

The aforesaid locking plates 22 are disposed adjacent the lower end of lthe inner section 12 and when this section 12 is extended upwardly the locking plates 22 reach a position where they come into register with the circle of slots 24 and locking pieces 25 carried by the outer member 26 and at this stage the band 26 carrying the looking pieces 25 is moved from its disengaged position into the position which causes the locking pieces 25 to slide into the recess 23 in the locking plates 22, the band 26 being then secured in this position by inserting the peg 27 through its lug 28 and into the second hole 31 of the aforesaid bracket 29 on the outer section 11.

Thus vvith this arrangement, the two sections are locked together against relative axial displacement, and together with the exactly similar locking means between the uppermost section 14 and the intermediate sections 12 the mast is locked in its extended position.

The boom 34 is mounted at the upper end 17 of the uppermost section 14 and may be in the form of a tubular lattice boom having a crane hook 35 which may be carried on a travelling carriage 36 moving lengthwise of the boom 34 in generally known manner. The boom 34 may be pivotally connected as shown at 37 to a member 38 at the top of the uppermost section 14 for lufling movement in a vertical plane. As 'shown in FIGURE 1, the slewing or traversing of the boom 34 is obtained by mounting the complete mast 10 upon a base member 39 which is itself mounted for slewing about a vertical axis for the purpose of traversing the boom 34 through anyl angle up to 360. ,V

Alternatively, the member 38 may be arranged as a slewing ring so as to be rotatable about the vertical axis of the upper section for the purpose of traversing the boom 34 through any angle up to 360.

The Ibase member 39 is mounted upon -a suitable vehicle such as a railway bogey 40 as shown in FIGURE 1 or alternatively on a crawler Itractor or other wheeled vehicle such as a trailer or tractor or lorry 50 as shown in FIGURE 4 or other road vehicle for the purpose of transpor-ting the complete crane in its collapsed state.

For collapsing purposes, the lowermost section 11 may be mounted as shown in FIGURES 1 and 4 for pivotal movement about a horizontal axis, such axis being spaced 0 A, L, LEVINE, M. L. AJEMAN,AssismmExaminef-s. H

a short distance above the lower end of the lowermost section 11 and, for example, there may be a pair of spaced apart pillars 42 supporting at their upper ends, a horizontal axis in the form of trunnions 41 for engagemen't by pivot pins 43 secured to the lowermost section 11, which is the outer section and the pivotal movement may be obtained by a Pneumatic ram 45 or rams connected between the base member 39 and the lowermost section 11.

When the mast is in the collapsed state as shown in FIGURE 3, it may be pivoted about its horizontal axis to lie in a substantially horizontal position and the boom 34 is also pivoted so as to lie in a su'bs-tantially horizontal position above the collapsed mast 10.

What I claim then is: i

1. A tower mast for a crane comprising a lower tubular section closed at its lower end, an intermediate tubular section open at both ends and slidable telescopically within the lower section, an upper tubular section closed at its top en-d and slidable telescopically within the intermediate section, means for supplying compressed air into the interior of themast, a first annular Sealing ring secured to the lower end of the intermediate section and` having air tight Sealing engagernent with the interior of the lower section, a second annular sealing ring secured tothe lower end of the upper section and having air tightv sealing engagement with the interior of the intermediate section, there being an annular space between -the lower and intermediate sections and 'between the intermediate and upper sections, and locking means for locking each two adjacent sections rigidly together located in said annular Spaces, each such locking means comprising a set of locking plates secured in spaced apart circumferen-- tial relationship to the exterior of the inner tubular section of the two anda corresponding set of locking pieces slidably mounted in spaced apart circumferential relationship on the outer section of the two, each such locking plate having a recess engageable with one of said lockingl pieces.

2. A tower mast according to claim 1 wherein each cumferencel through each one of which a locking piecev projects.v

References Cited by the Examiner UNITED STATES PATENTS 2,676,677 4/1954 Anderson et al 254--93 X 2,895,622 7/1959 Sundin 212-55 X 3,168,336 2/1965 Lawrence 212-144 X 3,194,411 7/1965 Durand 212-46 SAMUEL F. coLEMAN, Primary Examiner.

EVON C. BLUNK, Examiner.

Claims

1. A TOWER MAST FOR A CRANE COMPRISING A LOWER TUBULAR SECTION CLOSED AT ITS LOWER END, AN INTERMEDIATE TUBULAR SECTION OPEN AT BOTH ENDS AND SLIDABLE TELESCOPICALLY WITHIN THE LOWER SECTION, AN UPPER TUBULAR SECTION CLOSED AT ITS TOP END AND SLIDABLE TELESCOPICALLY WITHIN THE INTERMEDIATE SECTION, MEANS FOR SUPPLYING COMPRESSED AIR INTO THE INTERIOR OF THE MAST, A FIRST ANNULAR SEALING RING SECURED TO THE LOWER END OF THE INTERMEDIATE SECTION AND HAVING AIR TIGHT SEALING ENGAGEMENT WITH THE INTERIOR OF THE LOWER SECTION, A SECOND ANNULAR SEALING RING SECURED TO THE LOWER END OF THE UPPER SECTION AND HAVING AIR TIGHT SEALING ENGAGEMENT WITH THE INTERIOR OF THE INTERMEDIATE SECTION, THERE BEING AN ANNULAR SPACE BETWEEN THE LOWER AND INTERMEDIATE SECTIONS AND BETWEEN THE INTERMEDIATE AND UPPER SECTIONS, AND LOCKING MEANS FOR LOCKING EACH TWO ADJACENT SECTIONS RIGIDLY TOGETHER LOCATED IN SAID ANNULAR SPACES, EACH SUCH LOCKING MEANS COMPRISING A SET OF LOCKING PLATES SECURED IN SPACED APART CIRCUMFERENTIAL RELATIONSHIP TO THE EXTERIOR OF THE INNER TUBULAR SECTION OF THE TWO AND A CORRESPONDING SET OF LOCKING PIECES SLIDABLY MOUNTED IN SPACED APART CIRCUMFERENTIAL RELATIONSHIP ON THE OUTER SECTION OF THE TWO, EACH SUCH LOCKING PLATE HAVING A RECESS ENGAGEABLE WITH ONE OF SAID LOCKING PIECES.