US2392449A - Cylinder and piston - Google Patents

Description

Jan. 8, 1946. B. o. AUSTIN CYLINDER AND PISTON Fild Nov. 10, 1945 m I 6 C C (0 Q Q Q Q WITNESSES:

' assignee of this invention.

Patented Jan. 8, 1946 UNITED STATES PATENT OFFICE a CYLINDER AND PISTON Bascum 0. Austin, Lima, Ohio, assignor to Westinghouse Electric Corporatiom-East Pittsburgh, Pa., a corporation of Pennsylvania Application November 10, 1943, Serial No. 509,705

2 Claims. (01. 309-2) This invention relates to mechanical dampers of the type utilized in electrical apparatus and, in particular, to dashpots.

Dashpots have been widely employed in the electrical art as mechanical dampers for moving or vibrating elements, and have been constructed heretofore of many different materials. Attempts have been made to produce such mechanical dampers of materials which are unaffected by changes in' atmospheric conditions, stainless steel and other alloy-base materials of the non-corrosive type being used to a large extent. These dashpots have not been altogether satisfactory where they are used in conjunction with regulators for use on aircraft which requires exacting operation of all equipment. Thedifficulty of such dashpots has been traced to minute corrosion of the metallic bearing surfaces occasioned by the exposure to the atmospheric conditions and to distortion and damage of the component parts of the dashpot caused by handling and in the grinding of the parts. Such corrosion or damage seriously affects the operation of the regulator with which it is employed.

An object of this invention is to provide a dashpot which is non-corrosive and inert while being lightweight and having the characteristic of being self-lubricating.

Another object of this invention is the provision of a ceramic dashpot,

Other objects of this invention will be better understood by the following description when taken in conjunction with the accompanying drawing, in which:

Figure 1 is a view in side elevation of a regulator which utilizes the dashpot of this invention; and

Fig. 2 .is a view insection of a dashpot embodying the teachings of this invention.

, For purposes of illustrating the application of a dashpot to electrical apparatus, there is shown in Figure 1 a regulator H) of the type disclosed and claimed in Patent No. 2,326,036, issued August 3, 1943, to R. C. Jones and assigned to the The regulator or switching apparatus I preferably comprises a plurality of long thin spring members l2 formed of conductin material being secured against movement at one end in insulated relation with one another, the other end being free to move in one direction and being self-biased in the other direction against a stop member l4. The secured ends of the conducting spring members l2 are connected by leads I 6 to different taps of a resistor element l8 in such a manner that, as the spring members I2 are actuated away from'the stop member l4, progressive sections of the resistor element 18 are shunted by the engagement of contact members 20 carried'by the free ends of the conducting members 12.

Associated with the conducting members 12 is an electroresponsive device formed of an armature member 22 disposed for pivotal movement and biased as by means ofthe spring 24, to actu ate a driver member 26 toeffect the progressive movement of the stack of conducting members [2. A winding 28 is disposed to be energized under predetermined conditions to oppose the force of the spring 24 to control the movement of the armature member 22.

In order to stabilize the movement of "the armature member 22 and thedriver member .26 carried thereby, a dashpot 30 is carried by the frame supporting the electroresponsive apparatus, andis connected as by means ofa relatively stifi but fine'sprlng member 32 to the driver member 26. .As will be apparent, the dashpot effectively functions to dampen excessive movement of the driver member 26, as described ,in the Jones Patent No. 2,326,036 referred to hereinbefore,

The dashpot 30 utilized in conjunction with the electrical apparatus referred to hereinbefore is of special construction, so as to be substantially unaffected by changes in atmospheric conditions. Referring to Fig. 2 of the drawing, the construetion of the dashpot 30 is better illustrated, the dashpot comprising a cyliner housing 34 of metal, one end of the housing having an inwardlyturned flange member 36. I

,A base member 38 is provided within the cylinder housing 34 of a size to seat againstvthe flange 36 carried by the housing. The base member 38 preferably is formed with a cutout portion or section 40 about its periphery, so as to form a' centrally positioned guide section 42,the purpose of which will be describedhereinafter. VCen-i trally of the base member 38, an opening 44 is provided for receiving the endoi' the stem member 46 provided with connecting passages 48, 50 and 52 therein, a valve member 54 being disposed in the passage 52 and having a taperedend 55 for cooperating with and in the passages 48 and 50, to control the admission of air through the stem member 46. The position of the valve member 54 is regulated by adjusting the nut 58 carried on the threaded end of the valve member 54. The stem member 46 is provided with a shoulder 60 for seating against the base member 38, the end of the stem member being peened over as at 62 for ber 38.

As illustrated, a washer or'ring 64 of compressible material, such as a mixture of cork and synthetic rubber, or like material, is disposed to fit about the guide portion 42 of the base member in the cutout section 40 thereof', A cylinder 66 of ceramic material, such as porcelain, machined to have an inside diameter to fit about the guide portion 42 of the base member is disposed within the housing 34 with an 'end seated against the washer 64 of compressible material. As illustrated, in order to maintain the cylinder 66 in its assembled position with respect to the base mem ber 38, lugsf68 are provided in spaced relation about the end of the housing 34, and when the cylinder 66 is forced to seat tightly against the compressible washer 64, the lugs 68 are bent over the dashpot to the-driver member 26 is secured to the piston 16 by having an end thereof project through a small opening in the head of the piston, theend 12 of the wirebeing bent over and the wire being secured to the piston by a drop of any suitable cement 14, which also sealsthe small opening in the head of the piston.

The porcelain utilized informing the cylinder 66 and the piston Ill is a lightweight material,

and is particularly suited for such use as it is capable of receiving a high polish. In practice, the inner surface or side wall of cylinder 66 and the external surface of the'piston 'l'fl areground to size, very close tolerancesbeing obtained; and both surfaces are thereafter polished in any suitable manner to provide a very high finish, it being found that the polishing operationwill not have any affect upon the precision dimensions imparted to the cylinder and. piston by the grinding operationr When thusground and polished, it is found that the. piston and cylinder make a very close fit, substantially no leakage of air being found. between the side walls of the respective members. 7

Further, the highly polished ceramic material utilized in the piston 10 and the cylinder66 has 7 by'the adjustment of the valve member 54 to control the admission of air to the space between the head of piston 10 and the base member 38.

The dashpot of this invention is especially suited for use in aircraft where changes of atmospheric conditions are encountered in every flight. The ceramic material employed in forming the piston and cylinder of thefiashpflt are non-corrosive and inert, to substantially all chemicals and oils, and especially those encountered in services of the type encountered in aircraft applications. As the materials are lightweight, the resulting dashpot is especially suited for such applications, as weight is a'criterion in aircraft applications. Further, since the supply of ceramic material is abundant and classified as non-strategic, the dashpot of this invention releases important strategic materials which were utilized in the construction of dashpots prior to this invention.

Although this invention has been described with reference toa particular embodiment thereof, it is of course not to be limited thereto, except insofar as is necessitated by the scope of the appended claims.

, I claim as my invention:

1. In a dashpot constructed to receive a valve member, in combination, a cylinder member comprising a cylinder housing, a base member having an opening to receive the valve member therein disposed to fit within one end of the housing, a compressible member carried by the base member, a cylinder of ceramic material disposed in the housing to seat against the compressible member, and means carried by the housing disposed to retain the base member and the cylinder therein with the ceramic cylinder immovably seated against the compressible member, and a piston of ceramic material disposed within the cylinder for sliding movement therein, the ceramic cylinder and piston being polished to provide relatively smooth cooperating sliding surfaces thereon, the sliding surfaces being of only ceramic material.

2. In a dashpot constructed toreceive a valve member, in combination, a cylinder member comprising a cylinder housing, a-base member carried in the housing for closing one end thereof, the base member havin an opening therein for receiving the valve member, a compressible member carried by the base member, a cylinderlof ceramic material disposed in the housing to seat against the compressible member, and means car-: ried bythe housing disposed to retain the base member and the cylinder therein with the ceramic cylinder immovably seated against the compressible member, and a piston of ceramic material disposed within the cylinder for sliding movement therein, the ceramic cylinder and piston being polished to provide relatively smooth cooperating sliding surfaces thereon, the sliding surfaces being of only ceramic material.

BASCUM O. AUSTIN.

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