US2840244A - Boom stop ram - Google Patents

Description

" T. w. THOMAS, JR

`lune 24, 1958 BOOM STOP RAM l 2 Sheets-Sheet 1 Filed June 22. 1953 INVENTOR. Thomas W Thomasldk BY @L Aff'y T. W. THOMAS, JR

June 24, 1958 BOOM STOP RAM 2 Sheets-Sheet 2 Filed June 22. 1953 l m @i a l m m em,

Unid Se@ D BOOM sror RAM Y Thomas W. Thomas, Jr., San Rafael, Calif. Appncaaan June-zz, 195s, serial No. 363,139 1 Claim. v(Cl. 21a-'39) "I This invention relates to improvements in boom stop ram operators.

The principal object of this invention is to provide means for the controlling and stopping of the upward movement of a boom as used on cranes and the like load-lifting equipment.

A further object is.to provide means for gradually stopping the upward movement of a crane boom and to also disconnect the hoisting cable and apply the brakes at a predetermined point in the upward movement.

A further object is to produce a device of this character which may be operated by a vacuum or mechanical means.

A further object is to produce a device which may be attached to the ordinary crane without materially altering its construction.

A further object is to produce a device of this character which is economical to manufacture as well as simple in operation.

Other objects and advantages will be apparent during the course of the following description.

In the accompanying drawings forming a part of this specification and in which like numbers are employed to designate like parts throughout the same,

Fig. 1 is a side elevation of a crane having my invention applied thereto;

Fig. 2 is an enlarged fragmentary detailed view of the operating mechanism;

Fig. 3 is a similar view showing a modified form of my device;

Fig. 4 is a detailed view showing a mechanical means for releasing the clutch mechanism and applying the brake; v

Fig. 5 is a side elevation of the control valve; and

Fig. 6 is a vertical cross section thereof.

Cranes and the like load-lifting apparatus in most instances employ a pivoted boom which is raised and lowered through the medium of a cable secured to the top of the boom and being wound upon a driven drum.

It sometimes occurs that the operator may accidentally raise the boom too high or the load too high, or possibly the load line may break, thus causing the boom to whip upwardly. When any of these conditions occur,l it is possible that the boom may be seriously damaged by crumpling over the top of the cab, at the same time endangering the operator of the device.

I have therefore installed on the crane means for controlling the upward movement of the boom, whether such movement is intentional or unintentional, bringing the boom to a slow stop and applying brakes to the cables so as to hold the boom in any position at which it may come to rest. l

In the accompanying drawings, wherein for the purpose of illustration is shown a preferred embodiment of my invention, the numeral 5 designates the housing of a crane of standard construction having a boom 6 pivoted as at 7 and raised and lowered through the V. 2 Y y medium of a cable 8 wound upon a drum 9 driven by any desired motive power.

K At 11 I have shown a brake drum about which a brake band/12 is positioned. This brake band is controlled by a lever 13 connected to a pull rod 14 which may be actuated by a hand lever 16 so as to manually control the braking of the drum 9. The construction thus far described iscommon to the average crane mechanism.

My invention consists in means for automatically retarding 'the upward movement of the boom and also of means for applying the brake. n

Referring to Fig. V1, it will be noted that onthe top ofthrerl housing Ivhave Yshown a cylinder 17 in which Ais Vslidably'mounted a piston'18 vhaving a roller 19 which is adapted to be engaged by a plate 21 mounted on the boom 6 Fig. 2. This piston 18 has a linger 20 adapted to engage the head 26 of the piston 23, to be later described.

Within this cylinder 17 are positioned springs as described in my companion application Serial No. 357,129 covering a Spring Boom Stop.

Mounted on the top of the cylinder 17 is a valve cylinder 22 having a sliding piston 23, normally held in extended position by a spring 24 engaging the end of the cylinder 22 and a head 26 formed on the end of the piston 23 within the cylinder I provide a partition 27 having a valve seat against which a valve head 28 seats, this valve head being carried upon a reduced portion 29 of the piston 23.

A pipe 31 communicates with the interior of Ythe chamber 32 formed in the cylinder 22 by the partition 27 and a similar pipe 33 communicates with the chamber 34.

The pipe 31 extends from the cylinder 22 to a vacuum tank 36 in which a vacuum is maintained by a suitable vacuum pump 37 driven by an engine 38.

The pipe 33 connects to one side of a housing 39 in which is positioned a diaphragm which diaphragm is in turn connected to a pull rod 14.

In the Inodied form shown in Fig. 3, the construction is the same with the exception that I have moved the cylinder to a pointcloser to the pivotal point of the boom and I have applied the same numerals thereto.

In the form shown in Fig. 4, instead of using a vacuum,

arrangement, I have installed a nger 41 on the piston 18, which has an arm 42 adapted to engage the end 43 of a rocker arm 44 pivoted as at 46' and having its opposite end connected to a pull wire 47. This wire 47 is connected to theY lever 48 of the. master clutch 49.

The result of this construction is that when the boom moves upwardly, should the operator forget to release the clutch or should the boom whip upwardly, the following result will take place:

If the plate 21 of the boom engages the roller 19, the piston 18 will move inwardly against the tension of the springs referred to in my previous application. At the same time the finger 20 will engage the head 26 of the piston'23 and will move the valve 28 ot of its seat in the partition 27 with the result that vacuum will be caused in the chamber 34 and the pipe 33, which will draw the diaphragm in the housing 39 and move the pull rod 14 toward the right of the drawing, thus applying the brake and stopping any further upward movement of the boom.

In the modified form shown in Fig. 4, the action will be the same with the exception that instead of employing a vacuum, the pull wire 47 will serve to disconnect the clutch mechanism and thus stop the upward movement of the boom.

By manipulating the lever 16, the operator can lower the boom even though it is holding the valve 28 open as the pressure on the diaphragm caused by the moveaction o f the` diaphragm, thusreleasing the .brake and allowing the boom to lower. Y

It is to be understood that 'the form of my invention herewithtshpwaand. desqribsnitg billksn. ,2S nr: ferred example of the sarne" and thatjvariou'sjchanges relative` tothe .matsriah .size Shapqalid arrangemwtfof parts ,may beybresortedr to l withoutdeparting `the spirit of theinventlion or the scope oftl 'l e` subjoined claim.

Havingthusdecribed my invention, luclaim; In `a deviceyof the character described vthe combination withalpivoted'boom andmeansmfor raising Asaid b oom together witha remotely positioned boom` holding brake, of `afsprng loaded rmrhavins. a .wing and krfillfod4 positioned in alignment with thepiyotalpathof movement of said boom, said ramlbeing mounted Aremotely from the pivotalpoint of saidiboom whereby upwardlmovement ofsaid ,boom will engage saidwramrod 4to compress said `upward Amovement'offsaid 1 boom, a casing mountedV on said ram casing, a valve formed in said casing, a valve spring load to progressively build up resistance to the :l

a finger mounted on said ramrod and adapted to engage and slide said valve rod to open said valve, and vacuum means controlled by said valve for actuating said remotely located boom-holding brake to arrest further upward movement of said boom.

References Cited inthe tile` ofthis patent UNITED STATES PATENTS

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