US3215426A

US3215426A - Decelerating mechanism for loads

Info

Publication number: US3215426A
Application number: US271370A
Authority: US
Inventors: Engels Walter
Original assignee: Southern Machinery Co
Current assignee: Southern Machinery Co
Priority date: 1963-04-08
Filing date: 1963-04-08
Publication date: 1965-11-02
Anticipated expiration: 1982-11-02

Description

Nov. 2, 1965 w. ENGELS DECELLERATING MECHANISM FOR LOADS Filed April 8, 1963 mQE INVENTOR.

WALTER ENGELS BY X,

ATTORNEY United States Patent 3,215,426 DECELERATING MECHANISM FOR LUADS Walter Engels, Tryon N .C., assignor to Southern Machinery Company, Greer, S.C., a corporation of South Carolina Filed Apr. 8, 1963, Ser. N 271,370 4 Claims. (Cl. 267-1) This invention relates to a decelerating mechanism for heavy loads.

An object of the invention is to provide means for gradually decelerating and arresting the movement of heavy loads without impact or jarring, the invention being particularly applicable to the handling of missiles and other like objects which are delicate and heavy and Which must be handled with great care.

Another object is to provide a combined fluid pressure and spring-operated mechanism of the mentioned character which is self-replenishing or returnable upon removal of the load thereon.

Another object of the invention is to provide a mechanism of the mentioned type which is highly simplified and economical in construction, reliable and very eflicient in operation, and rugged and durable.

Another object is to provide a load decelerator which upon initial engagement with the heavy load softly cushions and gradually decelerates the same and then snubs the load to rest with a quickly increasing yet continuingly gentle arresting force.

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

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

FIGURE 1 is a side elevation of decelerating mechanism according to the invention and illustrating one use thereof,

FIGURE 2 is an enlarged central vertical longitudinal section through the mechanism in the relaxed or unloaded condition,

FIGURE 3 is a similar view of the mechanism under load, and

FIGURE 4 is an end elevation of the mechanism.

In the drawings, wherein for the purpose of illustration is shown a preferred embodiment of the invention, the numeral designates a main cylinder of required length which is initially open-ended and of uniform diameter. Rigidly secured within one end portion of main cylinder 10 is a relatively short tubular cylindrical guide sleeve 11 of somewhat reduced diameter, preferably welded to the main cylinder at 12. The inner end of sleeve 11 projects into the bore of the main cylinder and terminates therein at 13 forming a stop shoulder for a main piston 14 to be further described.

An extension tube and spring retainer 15 is slidably mounted within the bore guide sleeve 11 for reciprocation therein and has its outer end closed by an end cap or plate 16, preferably welded thereto and having a socket 17 for a cushioning pad 18 of resilient material such as a rubber-like material. The inner end of tube 15 is internally screw-threaded at 19 for the reception of a reduced end portion 20 of main piston 14, the latter being connected with the extension tube 15 in a preferably fluid tight manner. The main piston 14 includes an enlarged cylindrical portion 21 slidable within the bore of main cylinder 10 and adapted to engage stop shoulder 13 so as to have its outward travel with the tube 15 positively arrested when the mechanism is in the relaxed condition shown in FIGURE 2 or under no load.

The periphery of main piston 14 is grooved to receive ice an O-ring type seal 22 of Teflon or the like having sealing engagement with the bore of the main cylinder. The main piston 14 has a central cylindrical through orifice 23 of constant diameter as shown. The piston 14 and extension tube 15 constitute a unit in assembly for reciprocation relative to the main cylinder 10.

Mounted within the bore of tube 15 outwardly of main piston 14 is a secondary or spring piston 24 having a reduced tubular hub 25 engageable within the orifice 23, FIGURE 2, in spaced concentric relation thereto. The bore of secondary piston 24 slidably receives a reduced cylindrical rod extension 26 of an elongated gradually conically tapered metering or valve pin 27 which lies centrally within and extends axially of the main cylinder 10. A stop shoulder 28 is formed at the juncture of tapered pin 27 and rod extension 26, which parts are integrally formed. The rear end of metering pin 27 carries a reduced extension 29 upon which is rigidly mounted by welding a cylindrical head 30 carrying an O-ring type seal 31 of Teflon or the like for sealing the bore of main cylinder 10 near one end thereof. The head 30 is retained within the main piston bore by a snap ring 32 or the like, the removal of which allows the parts to be readily Withdrawn from the main cylinder.

The secondary piston 24 has an external O-ring type seal 32' for sealing the bore of the tube 15 and a similar internal sealing ring 33 for sealing engagement With the rod extension 26 over which the secondary piston is movable.

Ahead of the piston 24 in the dry chamber of the tube 15 is a stack of Bellville-type spring washers 34 which collectively constitute a strong compression spring between the end cap 16 and the forward side of the secondary piston, the rod extension 26 projecting into the bore of the spring structure, as shown. The spring structure in FIGURE 2 exerts a sufi'icient force only to maintain the parts of the mechanism in the fully extended position with the main piston 21 engaging stop shoulder 13 and the secondary piston 24 engaging the main piston.

A sturdy mounting bracket 35 is welded to one side of main piston 10 and extends radially thereof along substantially the full length of the same. The opposite ends of bracket 35 are apertured at 36 for connection respectively at 37 and 38, FIGURE 1, to a transfer cable 39 for a load 40 and to a support bracket 41 fixed to a bulkhead or wall 42. A diagonal stabilizing brace 43 interconnects the bracket 35 and bulkhead 42 as shown in FIGURE 1. The load 40 may be a crated missile or the like being transferred on the taut cable 39 to the deck of a ship or from the deck of a ship to an unloading platform or dock.

The main cylinder 10 is filled with hydraulic fluid 44 or like liquid in the main chamber between the head 30 and the sealed secondary piston 24.

In operation, when the load 40 initially engages the cushioning pad 18, the extension tube 15 and main piston 14 begin to move axially into the main cylinder 10 and the main piston moves away from the secondary piston 24, which simultaneously begins to move away from the shoulder 28. Initial compression of the spring structure 34 takes place and this spring structure at the beginning of compression offers little resistance to loading but elfects some resistance or decelerated effect upon the load. As the main piston 14 travels over the gradually tapered metering pin 27, the fluid 44 flows through the orifice 23 and meets with gradual resistance to flow because of the gradual closing of the orifice by the tapered metering or valve pin. Further loading of the mechanism at this point now causes the secondary piston 24 to move along the extension rod 26, FIGURE 3, and away from the main piston 14, and this action is due to the fact that the effective area of the piston 14 is decreased by its coaction manner and without jarring or impact. The main piston 14 in practice never actually reaches the maximum diameter portion of the tapered pin 27 which would fully close the orifice 23. FIGURE 3 shows a typical position of the mechanism under load where the main piston 14 has moved sufficiently to have the orifice 23 substantially constricted and the secondary piston 24 has moved outwardly from the shoulder 28 suificiently to compress the Bellville washer spring close to but not completely solid. Obviously, the mechanism can be designed to gently decelerate loads of almost any given magnitude and it is entirely practical to arrest loads of several tons gently by means of the invention mechanism.

It may now be seen that the mechanism initially decelerates'the load by means of mechanical spring compression acting in conjunction with gradually restricted movement of the main piston 14, and then finally with additional spring compression when the secondary piston 24 moves outwardly within the extension tube 15 because of its area relationship with the main piston 14, as above mentioned. As is well known, the Bellville type spring ofiers sharply increased resistance to compression near the end of compression, when the spring washers approach solid compression. The arrangement of fiuid compression or resistance and mechanical spring compression above described produces a mode of operation which could not be obtained efiiciently with fluid alone or with springs alone and the arrangement has proven to be ideal for the particular usage mentioned herein.

The mechanism is self-replenishing or resetting to the no load position of FIGURE 2 after removal of the load. In the relaxed position, the spring structure 34 is under sufiicient tension only to maintain the parts fully extended.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of the invention or scope of the subjoined claims.

Having thus described my invention, I claim:

1. A load decelerating mechanism comprising a main cylinder, support bracket means on the exterior of the main cylinder for attaching it to a fixed support and a transfer cable for a load, a guide sleeve within one end portion of the main cylinder and being of reduced diameter and defining within the main cylinder a stop shoulder, a main piston within the bore of the main cylinder inwardly of said shoulder and having a through opening, an extension tube secured to the main piston and slidably engaging the bore of said guide sleeve and projecting exteriorly of the main cylinder and guide sleeve, a secondary piston within the extension tube and having a through bore and a reduced hub portion engageable within said through opening of the main piston in spaced relation thereto, the secondary piston being engageable in one position thereof with one end of the main piston, a gradually tapering metering pin having a shoulder and an axial rod extension within the interior of the main cylinder, said rod extension engaging slidably through the bore of the secondary piston, means anchoring said metering pin within the main cylinder and forming a fluid seal between the pin and the bore of the main cylinder, additional means forming fluid seals between the secondary piston and the bore of the extension tube and said rod extension, a compression spring within the extension tube and engaging the secondary piston, and a mass of liquid within the bore of the main cylinder between the secondary piston and said anchoring and sealing means for said pin, said hub portion of the secondary piston engageable with the shoulder of said pin in one position of the secondary piston.

2. The invention as defined by claim 1, and a closure cap on the leading end of the extension tube engaging one end of said spring, and a resilient pad element carried by said cap,

3. The invention as defined by claim 1, and wherein said anchoring and sealing means for said pin is an enlarged head welded to said pin and carrying a sealing ring engaging the bore of the main cylinder and a snap ring engageable with said head and demountably secured within the main cylinder.

4. The invention as defined by claim 1, and wherein said compression spring is a multiplicity of Bellville-type spring Washers.

References Cited by the Examiner UNITED STATES PATENTS 2,370,942 3/ Dick 26764 2,373,505 4/45 Schnell 26764 2,737,301 3/56 Thornhill 267-64 X 2,892,626 6/59 Scott et al 26764 2,930,606 3/60 Trumper 2673 3,070,363 12/62 Ellis 2671 ARTHUR L. LA POINT, Primmy Examiner.