US3346281A

US3346281A - Lock mechanism for telescoping spar

Info

Publication number: US3346281A
Application number: US429003A
Authority: US
Inventors: James R Thompson
Original assignee: WASHINGTON IRON WORKS
Current assignee: WASHINGTON IRON WORKS
Priority date: 1965-01-29
Filing date: 1965-01-29
Publication date: 1967-10-10
Anticipated expiration: 1984-10-10

Description

Oct. 10, 1967 J. R. THOMPSON 3,346,231

7 LOCK MECHANISM FOR TELESCOPING SPAR Filed Jan. 29, 1965 is @4 h 2 "1i JAMES R.THOMPSON I INVENTOR.

AT TORN E 75 United States Patent 3,346,281 LOCK MECHANISM FOR TELESCOPING SPA R James R. Thompson, Seattle, Wash., assignor to Washington Iron Works, a corporation of Washington Filed Jan. 29, 1965, Ser. No. 429,003 7 Claims. (Cl. 28758) ABSTRACT OF THE DISCLOSURE A portable telescoping spar in which dogs hinged to the lower spar section sustain the upper spar section, being so formed that the same positively preclude retraction from said sustaining position unless the upper section is raised a prescribed distance above the sustained position.

This invention relates to portable spars for use in logging or other like or similar operations, and pertains especially to a telescoping-type portable spar in which an upper section is telesco ically associated with a lower section. The purpose is to provide a spar having considerable height when in an upright operating condition, while permitting the length to be shortened preparatory to lowering the spar into a horizontal position in course of moving the spar from one to another operating site, the shortened length allowing the move to be made with considerably greater ease than would otherwise be the case.

For its principal objects, the invention purposes to provide a telescoping spar in which the joint between the upper and lower sections of the extended spar is of advanced design, and particularly to provide for the spar a perfected means for releasably locking the two sections against endwise displacement when the same are in their operating extended condition.

A further important object is to engineer into the spar a locking means which is caused to perform its locking function automatically as the upper section reaches a predetermined point in its extension movement.

As a further object still the invention aims to provide a lock so formed and operated that the same produces a loud clang when the locking function is performed so as to give audible notice thereof to the operator controlling the extension of the spar.

These and other objects and advantages of the invention will appear and be understood in the course of the following description and claims, the invention consisting in the novel construction and in the adaptation and combination of parts hereinafter described and claimed.

In the accompanying drawing:

FIGURE 1 is a fragmentary vertical sectional view illustrating a telescoping spar having joint and lock mechanism embodying the preferred teachings of the present invention, the section line being shown at 11 in FIG. 2.

FIG. 2 is a fragmentary horizontal sectional view on line 22 of FIG. 1; and

. FIG. 3 is a fragmentary vertical sectional view on line 3-3 of FIG. 2.

Referring to said drawing, the upper section of the telescoping spar is denoted by the numeral 10, and the lower section by 11. The upper section is received within the lower section. Substantial clearance is provided between the two sections throughout the greater portion of the slide motion, with a piloting fit being established at two vertically spaced points as the upper section nears its upper extreme limit of travel. The piloting points have a close tolerance, say .020 diametral clearance, and are provided in each instance between the internal machined surface of an outer guide ring, as 12 and 13, and the external machined surface of an inner ring, as 14 and 15. These outer guide rings are welded or otherwise made a fixed part of the lower spar section and the inner guide rings, similarly, are welded or otherwise made a fixed part of the upper spar section. The two spar sections are desirably of fabricated construction and are so illustrated in FIG. 1. To give perhaps greater clarity, FIG. 3 deletes the division lines between the integrally joined parts. These parts include, as an integral component of the upper spar section 10, a bearing ring surrounding the upper spar section in a position spaced above the latters upper guide ring 14.

The bearing ring has a thrust-taking shoulder 17 at the bottom which is disposed perpendicular to the axial line of the spar, and presents a curtailed taper at the top. The bevelled flank which this taper provides is denoted by 18, and the upwardly facing flat 0r truncation by 19. The

function of the flat 19 is to engage a stop carried by the lower spar section and thereby provide an upper extreme limit to which the upper section may travel when the spar is being extended. This stop is comprised of an inturned flange 20 formed at the head end of a bonnet 21 extending upwardly as a nose prolongation of the lower spar section 11. The bonnet proper is spaced a moderate distance above a thickened head end part 22 of the lower spar section and has depending feet 23 at equidistantly spaced intervals of the circumference bearing upon said head end of the lower spar section. Bolts 24 secure the bonnet to the spar section. For ease of assembly the honnet is split on a diameter and has its two halves secured together by bolts 25 (see FIG. 2).

While not shown in the drawing one of the two spar sections presents a key working in a key-way which is provided by the other spar section. This is conventional with telescoping spars to prevent relative rotation as the two sections are telescoped.

The upper spar section 10 is raised and lowered within the lower spar section 11 by power. This means therefore is no part of the present invention and suflice it to say that the same may be performed in the usual or a suitable manner. The bonnet permits the upper section to be raised to a position whereat the thrust shoulder 17 of its bearing ring is elevated a fair distance above the head end 22 of the lower spar section.

The locking mechanism of the present invention comprises a set of bell-cranks 26 each mounted by a hinge pin 17 for reciprocal swing motion about an axis which is tangent to a circle having the axis of the spar as its center. The hinge pins each have their ends journaled in a respective pair of separated cars 30 which are integral with the lower spar and project from the external surface thereof. Each of the bell-cranks occupies a plane radial to the spar midway between an adjacent two of said depending feet 23.

The working arms of the bell-cranks extend upwardly from the hinge pin and have an angular configuration when viewed from the side to each present an inturned dogging end 31 which, in the reciprocal swing action of the bell-crank, moves inwardly and outwardly between an advanced operating position whereat the dog underlies the thrust shoulder 17 of the bearing ring into and from a retracted inoperative position whereat said dog clears the bearing ring. When occupying said operating position, the dog has the thrust shoulder seated firmly thereon and itself bears firmly upon the head end 22 of the lower spar section.

The power arms 32 of the bell-cranks extend outwardly from the hinge pin and pivotally connect with the upper end of the connecting rod 33 for the piston of a doubleacting air cylinder 34 having its lower end pivoted, as at 35, to an ear 36 integral with the lower spar section. The several cylinders are connected for gang operation by

flexible hoses

37 and 38 extending between the cylinders and a control valve (not shown), the valve permitting air under pressure to be supplied from a supply source to either end of the cylinders, or dumped from the cylinders. A spring 40 acts upon a keeper 41 to urge the arm 32 upwardly so that the dog 31 normally occupies the position in which it is shown in FIG. 1.

The force of the springs 40 is overpowered by air pressure when it is desired to retract the dogs preliminary to lowering the upper spar section, and it will be understood, when such lowering is to be performed, that the upper spar section must first be momentarily raised in the moderate degree necessary to provide clearance for the dogs to swing outwardly. When raising the upper spar section within the lower spar section the pressure of the springs is augmented by air pressure supplied to the lower ends of the cylinders 34. As a consequence, the dogs, which are pressed outwardly by the bevel 18 as the upper spar section nears the upper extreme limit of its permitted travel, are driven inwardly with considerable force when the continued rise of the bearing ring brings its thrust, shoulder above the dogs. The loud clang which results as metal strikes metal is audible throughout the full extent of a logging yard, signalling the operator to discontinue the upward travel being given to the upper spar section and lower said upper section into its operating position whereat the weight of the upper spar section is passed through the dogs directly from the bearing ring to the head end of the lower spar section, with the dogs being locked by such weight load against retraction. This loading is such that should pressure air be accidentally fed to the cylinders after the two spar sections have been locked in the manner described the same would be ineffective to retract the dogs.

It is believed that the invention will have been clearly understood from the foregoing detailed description of my now-preferred illustrated embodiment. Changes in the details of construction may be resorted to without departing from the spirit of the invention and it is accordingly my intention that no limitations be implied and that the hereto annexed claims be given the broadest interpretation to which the employed language fairly admits.

What I claim is:

1. In a telescoping spar of a type which stands upright when in its operating position, in combination: a lower spar section provided adjacent its upper end at spaced intervals of the circumference with upwardly facing support means, an upper spar section held against turning relative to the lower spar section and received for telescoping slide movement within the lower section, said upper section adjacent its lower end being provided with a respective downwardly facing surface for each of said support means spaced circumferentially of the upper section in correspondence with the spacing of the support means and.

serving as thrust shoulders, said shoulders when the spar is extended to its full height beingraised to a level somewhat higher than the level occupied by the support means, a respective lever for each of said support means and its related shoulder having an inverted L-shape when viewed from the side with the upright leg of said L being hinged to the lower spar section for swing motion about an axis tangent to a circle having the axis of the spar as its center and the horizontal leg of the L extending as a dog radially inwardly relative to the extended spar and by said swing action moving into and out of a position whereat the upper surface of the dog underlies the shoulder and the under surface overlies the support means, and means for moving the dogs in said radial movement, the upper section of the spar, when the spar is in an operating condition, occupying a level such that its weight is passed directly through the dogs from the thrust shoulders to the support means, a limit stop being provided prescribing a higher level to which the upper section can be raised, the dog-forming leg are said radial movement travelling a path which is interrupted by said shoulder when the spar is in its operating condition and thus requires that the upper spar section be first raised a prescribed distance before the dog can be retracted preliminary to a lowering of the upper spar section into the lower spar section.

2. A telescoping spar as claimed in claim 1, means being provided to yieldingly urge the dogs inwardly into operating positions.

3. A telescoping spar as claimed in claim 2 in which the thrust shoulders are produced by the bottom face of a ring surrounding the upper spar section and made an integral part thereof, the upper portion of the ring being bevelled, said bevel pressing the dogs outwardly against the force of said yielding means as the ring traverses the dogs in course of raising the upper spar section.

4. A telescoping spar as claimed in claim 1, each of said levers comprising one arm of a respective bell-crank having the other arm extending outwardly from the hinge axis, the means for moving said dogs radially of the spar comprising for each dog a respective double-acting vertically extending pneumatic jack having one end attached to the lower spar section and the other end attached to the outwardly extending arm of the bell-crank.

5. A telescoping spar as claimed in claim 4, the thrust shoulders being produced by the bottom face of a ring surrounding the upper spar section and made an integral part thereof, the upper portion of the ring being bevelled, said bevel pressing the dogs outwardly, against the yielding force of pressure air supplied to the pneumatic jack, as the ring traverses the dogs in course of raising the upper spar section.

6. A telescoping spar as claimed in claim 5, the thrust shoulders being produced by the bottom end face of a ring surrounding the upper spar section and made an integral part thereof, a bonnet being provided which sur-' mounts the lower spar section in surrounding relation to the upper spar section and is formed at its top end with an inwardly directed flange engaged by the upper end face of the ring to serve as said limit stop for the upward movement of the upper spar section relative to the lower spar section.

7. In a telescoping spar of a type which stands upright when in its operating position, in combination: a lower spar section, an upper spar section received for telescoping slide movement within the lower spar section and provided adjacent its bottom end with a plurality of downwardly facing thrust shoulders which become exposed when the upper section is raised to a height placing the' spar in an operating condition, a plurality of dogs, one for each of said shoulders, hinged to the lower spar section for movement radially of the spar into and out of an operating position where the same underlie the exposed shoulders and pass the weight of the upper spar section into the lower spar section, a set of double-acting pneumatic jacks each having one end attached to the lower spar section and the other end to a respective one of the dogs for yieldingly powering the dogs inwardly into and outwardly out of said operating position, said dogs and the upper spar section being each composed of a resonant metal and being each so formed and arranged that when the dogs are powered into said operating position the dogs References Cited UNITED STATES PATENTS Goett.

Smith et a1.

Lee 52-115 Badertscher et a1. 52115 10 Bender et a1 52-1 15 Lebourg 285-302 Bourassa 52632 Johnson et a1. 52115 Lawrence 285298 CARL W. TOMLIN, Primary Examiner.

W. L. SHEDD, Assistant Examiner.

Claims

1. IN A TELESCOPING SPAR OF A TYPE WHICH STANDS UPRIGHT WHEN IN ITS OPERATING POSITION, IN COMBINATION: A LOWER SPAR SECTION PROVIDED ADJACENT ITS UPPER END AT SPACED INTERVALS OF THE CIRCUMFERENCE WITH UPWARDLY FACING SUPPORT MEANS, AN UPPER SPAR SECTION HELD AGAINST TURNING RELATIVE TO THE LOWER SPAR SECTION AND RECEIVED FOR TELESCOPING SLIDE MOVEMENT WITHIN THE LOWER SECTION, SAID UPPER SECTION ADJACENT ITS LOWER END BEING PROVIDED WITH A RESPECTIVE DOWNWARDLY FACING SURFACE FOR EACH OF SAID SUPPORT MEANS SPACED CIRCUMFERENTIALLY OF THE UPPER SECTION IN CORRESPONDENCE WITH THE SPACING OF THE SUPPORT MEANS AND SERVING AS THRUST SHOUDLERS, SAID SHOULDERS WHEN THE SPAR IS EXTENDED TO ITS FULL HEIGHT BEING RASIED TO A LEVEL SOMEWHAT HIGHER THAN THE LEVEL OCCUPIED BY THE SUPPORT MEANS, A RESPECTIVE LEVER FOR EACH OF SAID SUPPORT MEANS AND ITS RELATED SHOUDLDER HAVING AN INVERTED L-SHPED WHEN VIEWED FROM THE SIDE WITH THE UPRIGHT LEG OF SAID L BEING HINGED TO THE LOWER SPAR SECTION FOR SWING MOTION ABOUT AN AXIS TANGENT TO A CIRCLE HAVING THE AXIS OF THE SPAR AS ITS CENTER AND THE HORIZONTAL LEG OF THE L EXTENDING AS A DOG RADIALLY INWARDLY RELATIVE TO THE EXTENDED SPAR AND BY SAID SWING ACTION MOVING INTO AND OUT OF A POSITION WHEREAT THE UPPER SURFACE OF THE DOG UNDERLIES THE SHOULDER AND THE UNDER SURFACE OVERLIES THE SUPPORT MEANS, AND MEANS FOR MOVING THE DOGS IN SAID RADIAL MOVEMENT, THE UPPER SECTION OF THE SPAR, WHEN THE SPAR IS IN AN OPERATING CONDITION, OCCUPYING A LEVEL SUCH THAT ITS WEIGHT IS PASSED DIRECTLY THROUGH THE DOGS FROM THE THRUST SHOULDERS TO THE SUPPORT MEANS, A LIMT STOP BEING PROVIDED PRESCRIBING A HIGHER LEVEL TO WHICH THE UPPER SECTION CAN BE RAISED, THE DOG-FORMIGN LEG IN ITS SAID RADIAL MOVEMENT TRAVELLING A PATH WHICH IS INTERRUPTED BY SAID SHOULDER WHEN THE SPAR IS IN ITS OPERATING CONDITION AND THUS REQUIRES THAT THE UPPER SPAR SECTION THE FIRST RAISED A PRESCRIBED DISTANCE BEFORE THE DOG CAN BE RETRACTED PRELIMINARY TO A LOWERING OF THE UPPER SPAR SECTION INTO THE LOWER SPAR SECTION.