US914831A - Pneumatic buffer for self-propelled vehicles. - Google Patents

Description

MELVILLE P. HAYWARD, OF QUINCY, MASSACHUSETTS.

PNEUMATIC BUFFER FOR SELF-PROPELLED VEHICLES.

Specification of Letters Patent.

Patented March 9, 1909.

AApplication filed May 9, 1907, Serial No. 372,671. Renewed August 21, 1908. SerialNo. 449,744.

To all whom 'it may conce/m:

Be it known that l, MELVILLE P. HAY- WARD, a citizen of the United States, residing at Quincy, in the county of Norfolk and State of Massachusetts, have'invented new and useful Improvements in Pneumatic Buffers for Self-Propelled Vehicles, of 'which the following is a specification.

This invention relates to shock absorbers or bufiing devices intended for use in connection with self-propelled vehicles so as to permit easy running and movement of the veln'cle body and prevent the transmission of shocks from the running gears thereto.

The invention has for one of its objects to improve and simplify the construction and operation of devices of this character so as to be comparatively easy and inexpensive to manufacture and keep in repair, thoroughly reliable and ecient in use, and of substantial and durable design.

A further object of the invention is the provision of a plurality of hollow iston-containing cylinders in which are co ed bodies of elastic and hydraulic media that cooperate to absorb the shocks exerted on the device, means being employed for equalizing the air or elasticmedium in the chambers.l

rA further object is the provision of a pneumatic buffer comprising a plurality of aircontaining cylinders in which are arranged pistons of special form, and an additional cylinder in which is Va vhydraulic medium through which a piston ehurns back and forth under movement ofthe body of the vev hicle to which the buffer is applied.

. With these objects in view and others, as will appear as the ydescription proceeds, the invention comprisesthe various novel features of construction and arrangement of parts Which will be more fully described heremafter and set forth with particularity in the claims appended hereto.

In the accompanying drawing, which illustrates one of the embodiments of the invention, Figure 1 is a central vertical section of the device partly in elevation. Figs. 2 and 3 are bottom plan views of modified forms of piston for the middle cylinder. Fig. 4 is a detail sectional view of a modified form of main cylinder.

`Referring to the drawing, 1, designates a suitable base-plate on which are fixed spaced upright main cylinders 2 and a central or intermediate secondary cylinder 3. In each of the main cylinders 2 is a hollow piston' 4 closed at its up er end bya cup 5 provided with apertured ugs 6, and secured to the lugs of the pistons is a cross-head or bar 7 hingedly connected at its ends to the pistons by the bolts 8. By this means a limited unequal movement of the pistons is permitted. On the upper ends of the cylinders are glands or packing nuts 8 that hold under compression suitable packing rings 9 resting on the u per ends of the cylinders, thus preventing lea age of liquid from the latter. yTo further assist in preventing leakage, the lower ends of the pistons are each interiorly reduced to provide a relatively thin and yieldable annulus 10 Which is forced outwardly radially into in-,

timate contoact with the internal wall of the cylinder by the pressure of the li uid so that the greater the pressure in the cy inders, the tighter will the thin portions 10 of the pistons enga e the cylinders. Arranged in each cylin er is an upright pipe 11 open at its upper end, and the lower ends of the pipes are connected by a passage 12 in the base plate so as to constitute an equalizing means for permitting the pressure in one cylinder to be the saine as that in the other, thus insuring the uniform vertical movement of the pistons.

In each of the cylinders 2 is a body of oil or othersuitable liquid that is somewhat below the upper end of the pipes 11 for the purpose of affording a large air space t9 give the pneumatic cushioning effect. The air pressure is .established in the cylinders by means of an air pump that is adapted to be connectedwith a valve 5 on one ofthe cylinder caps 5, the valve being of that type commonly employed in pneumatic tires.

ln the secondary cylinder 3 is a piston 13 having a plurality of vertically extending ports 14 through which the oil or other hydraulic medium iilling the cylinder 3 can pass back and forth to opposite sides of the piston, as the latter reciprocates. The piston is provided with a rod 15 that is bolted to the cross-head 7 so that all of the istons will move simultaneously. The mid le cylinder and piston constitute a resistance device for preventing sudden and excessive movement of the movable elements 4 and in order to permit the parts to move up and down uite freely within certain limits above and be ow the central position, the cylinder 8 is provided with vertically extending channels 3 in its internal Wall that are of different lengths so as to permit fluid to readily pass the piston 13 during the first part of its movement in either direction and gradually resist the' by-passing of the liquid as the` piston moves farther and farther from the central position. ln other words, the central piston and cylinder produces a gradually increasing resistance against the movement of the elements 4 of the main cylinders. The channels 3 may be cast or otherwise formed in the cylinder and the latter bored so that the piston will make a good fit therein. If desired, the cylinder does not require to be bored but may be fitted with a lining 3a, as shown in Fig. 4, which is provided with apertures 3b communicating with the channels 3c of the cylinder.

In order to prevent a positive check or shock by the piston 13 moving past the longest channel 3 under extreme shocks or blows sustained by the vehicle, the piston 13 has a plurality of ports 14 through which the liquid can pass from one side`of the piston to the other. These ports are controlled by a fiap valve 16 for retarding the passage of the liquid upwardly and uppet valves 17 for resisting the downwardpmovement of liquid. The valves 17 are provided with stems 18 that are engaged by springs 19 that tend to hold the valves seated. The springs 19and Hap valve 16 are secured to a stem 20 extending through the piston rod 15. The flap valve 16 springs away from the ports when the pressure of the liquid on the upper side of the piston reaches a certain point, as do also the valves 17 when the pressure on the underside becomes great enough. 'The valve 16, 'as shown in Fig. 2, may be provided with ports 16 which can be brought into complete or partial register with the ports 14, thereby controlling the freedom with which the liquid can pass to the bottom side of the piston.

In ractice, the buffers are attached toa vehic e in such a manner that the pistons will move up and down to follow the relative movement between the wheels and body of the vehicle. The compressed air in the upper ends of the cylinders 2 will be coinpressed upon the downward movement of the head 7 and thus cushion the shocks that would be transmitted to the vehicle body and the expansion of the air assists to return the parts in normal position. Any excessive and violent movement of the vehicle body is retarded or checked by the cylinder and piston 3, this checking occurring, however, more or less gradually, so as to eliminate the transmission` ofshocks to the vehicle body.

From the foregoing description, taken in connection with the accompanying drawing, the advantages of the construction and of the method of o eration will be readily apparent to those s ed in the art to which the invention appertains, and while I have described the principle of operation of the invention, together with the apparatus which I now consider to be the best embodiment thereof, I desire to have it understood that the ap aratus shown is merely illustrative and t at such changes may be made when desired, as are within the scope of the claims.

Having thus described the invention, what I claim is y 1. In a device of the class described, the combination of a plurality of main piston cylinders, the cylinders each containing a body of liquid and com ressible fluid, equalizing means between t e cylinders, means for 'onnecting the pistons, and a h draulic check; device connected with the sai means. 2. In a device of the class described, the combination of a plurality of cylinders adapted to contain a body of liquid and a compressible iluid, pressure equalizing means between the portionsk of the cylinders containing the compressible fluid, aA hollow piston in each cylinder provided with thin walls that yieldingly engage the internal surfaces of the cylinders under the pressure of the liquid therein, and packings on the cylinders and disposed around the istons.

3. In a device of the c ass described, the combination of a plurality of cylinders adapted each to containa'body of liquid and a compressible iiuid, a"common,base plate having a passage, and open-ended tube connected with the passage and extending into the air ,space of the cylinders, pistons in the cylinders, means for connectin the pistons to act in unison,and a hydrau 'c check device for retarding' the movement of the pistons.

4. In a device ofthe class described, the combination of a plurality of parallel cylinders each adapted to hold a body of li uid and elastic fluid, hollow pistons in the cy 'nders, caps for the outer ends of the pistons,

a cross head hingedly connected with the ca s, a secondar cylinder adapted to be iillled with a liquid, a piston movable back and forth therein and provided with ports, valves controlling the ports, and a connectionbetween the cross head and the piston in the secondary cylinder.

5. In an apparatus of the class described, the combination of a plurality of parallel cylinders, relatively movable elements therein, there being a body of liquid and compressible fluid in each cylinder, a device for connecting the elements to move in unison, means for connecting the iiuid spaces of the cylinders permanent y together, a hydraulic checking device associated with the cylinders and includin a movable element, and means for positive y connecting the movable eleme'nt with the device.

6. In an apparatus of the class, described, the combination of a base plate, a pair of parallel cylinders secured to the base plate and containing a bod of liquid and of com-- pressible Huid, cham ered istons movable 1n the cylinders, upright tu 'es mounted on the base plate 'and extending vu Wardly through the cylinder and' into the c ambers of the pistons, a conduit connecting the ends ofthe tubes to ether, a cross memberhingedly connected Wit `the pistons, a hydraulic motionv chec device supported on `the base plate and disposed between the cylinders 'said device having al movable element; and

means for connecting the element lWith-the said member. p f 7. In an apparatus ofthe class described the combination with cushioning means, of a retarding device associated therewith, said devicecomprising a cylinder having longitudinal channels mits internal wall, a lining for the cylinder having apertures communieating with the'channels, a iston movable in the cylinder, ports in the piston, and valves 'controlling the orts.

In testimon Whereo I aix my-.signature yin presence'o j two witnesses. MELVILLEP. Witnesses: 1

CLIFFORD B. DANIELS,A BERTHA R. DANIELs.

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