US3038448A - Cylinder construction - Google Patents

Description

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IINVEN'ITOR HOWARD D. C ORW/N ATTORNEY H. D. CORWIN CYLINDER CONSTRUCTION June 12, 1962 Filed March 11, 1960 a I M? United States The invention pertains to a construction for expansible chamber motors, and particularly relates to an improved manner for assembling the basic components of this type of motor.

The basic components of a conventional expansible chamber motor include a tubular cylinder being enclosed at each end by a head element. A piston is reciprocally mounted within the cylinder and has a piston rod aflixed thereto which extends through one of the head elements. Ports are often formed in the head elements for communication with the cylinder interior on opposite sides of the piston, and sealing means are employed between the piston rod and the head the rod extends through to prevent the loss of the pressurized medium. As high fluid or gas pressures are often produced within the cylinder, substantial means must be employed to affix the head elements to the ends of the cylinder. One of the most common means employed to maintain the heads upon the cylinder is to extend tie rods between the heads parallel to the piston rod whereby the tie rods may be tensioned to draw the heads toward each othe and maintain their assembly upon the cylinder. This type of connection produces a very strong assembled cylinder. However, disadvantages arise from this construction as will be later explained. The heads may be also assembled to the cylinder by means of complementary threads formed on the cylinder and heads. While this construction produces a more sightly appearance than the use of tie rods, it is more expensive to manufacture as considerable accuracy in the production of the threads is required.

The heads of conventional cylinder constructions often contain the ports for the cylinder, as mentioned above, and as the mounting means of the motor is usually fixedly associated with the heads in one manner or another, the ports are associated with the motor mounting means in a predetermined nonadjustable relation. It is -a known practice to provide the heads with a square or rectangular outer configuration wherein the motor is mounted with one of the flat surfaces of the head resting upon the supporting element, and bosses often are formed integrally with the heads and extend therefrom for positioning mounting bolts therethrough to affix the motor to the support member. In such conventional motor constructions wherein the ports and mounting means are either formed upon or related to the heads in a nonadjustable manner, it is necessary to first mount the motor to the support element and then conform the piping or conduits connected to the ports to the relative position of the ports. As expansible chamber motors are employed in a wide variety of applications, the expansible chamber motor manufacturer cannot determine the most advantageous angular position of the port or ports With respect to the mounting means formed on the head and, hence, the installation of cylinders often becomes quite diflicult due to clearance problems adjacent the ports after the cylinder is mounted.

To overcome the above mentioned problems, it is the purpose of the invention to provide an expansible chamber motor construction wherein the ports and mounting means may be angularly adjusted relatively to each other wherein the ports may be positioned to the mounting means in the most advantageous relationship for a particular application.

A further object of the invention is to provide an exatent ice 'pansible chamber motor construction employing ported heads and a tie rod assembly wherein the tie rods maintain the assembly of the heads to the cylinder as well as the assembly of the mounting means to the heads.

A further object of the invention is to provide an improved expansible chamber motor construction which is economical to manufacture and provides improved flexibility and versatility in the use of the motor.

Yet another object of the invention is to provide an expansible chamber motor construction which permits a wide variety of motor components to be assembled from existing stocks and wherein the mounting means employed for the motor may be readily changed and a wide variety of mounting means employed with a single set of heads and associated cylinder.

A further object of the invention is to provide an improved expansible chamber motor construction wherein a packing gland is employed in one of the heads for association with the piston rod, and the mounting means simultaneously maintains the motor in assembled relation, and the gland assembled to the head.

These and other objects of the invention arising from the structural relationships and details thereof, will be apparent from the following description and accompanying drawings, wherein:

FIG. 1 is a perspective view of an expansible chamber motor in accord with the invention with a foot type mounting means,

FIG. 2 is a sectional elevational view of the motor of FIG. 1 taken along line 'I-I thereof,

FIG. 3 is an elevational side view of another embodiment of a motor in accord with the invention, having a center mounted trunnion support,

FIG. 4 is an end elevational view of the motor embodiment of FIG. 3 taken from the right end thereof,

FIG. 5 is a perspective view of another embodiment of the invention using a flange mounting means, and

FIG. 6 is an elevational fragmentary view of an end of a cylinder in accord with the invention, showing a swivel type mounting plate.

The exterior appearance and relationship of the components of an expansible chamber motor employing the principles of the invention will be apparent from FIG. 1. The motor 10 consists basically of a cylinder element 12 being closed at each end by head members 14 and 16 having ports 18 and 20 formed, respectively, therein. The ports 18 and 20 are in communication with the interior of the cylinder. A pair of plates 22 and 24 are associated with the heads 14 and 16, respectively. The plates 22 and 24 are provided with suitable holes 26 and are of a greater dimension than the heads wherein tie rods 28 may be inserted through the holes 26 and interconnect the plates 22 and 24. The ends of the tie rods may be provided with threads and nuts 30 screwed thereon which will permit the tie plates 22 and 24 to be drawn toward each other, maintaining the cylinder in assembled relation. The piston rod 32 extends through the head 16 and plate 24, and a packing gland 34 is interposed between the piston rod and head 16 to prevent the escape of the pressurized medium, either gas or a hydraulic fluid, from the interior of the cylinder. Each of the plates 22 and 24 are provided with a pair of mounting feet 36 which are preferably bent at right angles to the general plane of the plates, and holes 38 are provided in the feet to permit screws or bolts to extend therethrough. The motor may thus be mounted upon a support surface wherein the under side of the feet 36 contact the support surface and thereby support the motor. The screws or bolts extending through the holes 38 affix the motor to the support surface.

The internal structure and the relationship of the above described components of the invention may be more fully appreciated from the cross-sectional FIG. 2. A piston 40 having sealing rings 42 is reciprocally mounted Within the cylinder 12 and the piston rod 32 is affixed to the piston in the conventional manner. The port 18 communicates with the bore 44 which opens into the left end of the cylinder chamber, and the port communicates with a bore 46 opening into the right end of the cylinder chamber. A cushion seal 48 is mounted in the head 14 concentric with the horizontal axial portion of the bore 44, and a cushion seal 50 is concentrically aflixed within the head 16 in a similar fashion. The cushion seals 48 and 50 cooperate with cylindrical cushions 52 and 54, respectively, mounted upon the piston rod 32 to cushion the working stroke of the piston and piston rod at the ends of the stroke and form no part of the present invention. The operation of the cushions and cushion seals are described in detail in the U.S. Patent 2,719,510, filed July 21, 1959, or U.S. Reissue Patent No. 24,532.

Thus, as pressurized gas or fluid is injected into the port 18, the piston 40 is forced to the right. Introduction of pressurized fluid into the port 20 forces the piston to the left. it will be understood that the fluid exhausts from the nonpressurized side of the piston during the piston movements.

The heads 14 and 16 are preferably of cylindrical external configuration, and are recessed at 56 to provide a shoulder receiving the ends of the cylinder 12. Annular grooves 58 are also provided in the heads to receive an O-ring to insure a fluid sealing engagement between the heads and cylinder.

The packing gland '34 is mounted within the head 16 concentric to the axis of the piston rod, and surrounds the rod to form a sealed connection between the head and piston rod in the known manner. A recess 60 is defined in the head 16 to accurately locate the gland 34 therein.

As will be apparent from FIG. 2, the plates 22 and 24 are provided with an inner configuration which permits the plates to intimately contact the end surface of the heads. The plate 24 is provided with a bore 61 to provide for the gland 34 and piston rod 32. The bore 61 conforms to a stepped diameter of the gland, and the portion of plate 24 adjacent the gland step acts as a shoulder to maintain the gland 34 within the head 16.

The expansible chamber motor of the invention is assembled in the following manner. The piston and piston rod are previously assembled to form a unit, and this unit may be inserted into the cylinder 12. Assuming the seals 48 and 50 to be assembled to their respective heads and the O-rings to be within the grooves 58, the heads 14 and 16 may now be placed over the ends of the cylinder, as shown. During this operation it is desirous, though not necessary, to determine the desired position of the ports 18 and 20 to each other and, therefore, the heads will be assembled to the cylinder such that the ports extend in the desired radial direction. The plates 22 and 24 are then placed upon the ends of the heads 14 and 16, respectively, and the tie rods 28 are inserted through the holes 26 and the nuts 30 are loosely threaded upon the tie rods.

If the ports 18 and 20 are now angularly related to the plate feet 36 in the desired manner, the nuts 30 may be tightened to draw the plates 22 and 24 into intimate engagement with their associated heads, thereby drawing the heads toward each other and positively assembling the heads to the cylinder with considerable pressure. If it is desired to angularly adjust the heads prior to tightening of the nuts, the annular recesses 56 permit the heads 14 and 16 to be rotated relative to the cylinder 12 and plates 22 and 24 without affecting the efficiency or the operation of the expansible chamber motor in any manner. Upon rotating the heads to produce the desired angular relationship of the ports 18 and 20 to the mounting feet 36, the nuts 30 are then tightened, as described above, to complete the assembly of the motor. Upon complete tightening of the nuts 30, the cooperation of the plate 24 with the gland 34 will firmly hold the gland within the recess 60 of the head 16 and positively maintain thi assembly. It will be thus appreciated that upon the tightening of the nuts 30, the tensioned tie rods 28 simultaneously maintain the assembly of the heads 14 and 16 upon the cylinder 12, the plates 22 and 24 upon the heads 14 and 16, and the gland 34 in the head 16. This construction permits the ports to be related in any desirable angular relationship to each other and to the mounting means, eliminates accurate exterior machining of the outer surfaces of the heads, as is the case wherein square or rectangular heads are employed, and permits various sizes of cylinders to be assembled from a few components.

As expansible chamber motors are utilized in a wide variety of applications, it is often desirable to provide mounting means of a type other than that illustrated in FIGS. 1 and 2. FIGS. 3 and 4 illustrate an embodiment of the invention wherein the motor may be mounted upon a trunnion support which is centrally located with respect to the length of the motor. In this and other embodiments, components similar to that of the above described embodiment are referred to by like reference numerals, and the plates 62 and 64 are similar to the plates 22 and 24, respectively, except that the plates 62 and 64 do not have feet formed thereon. An annular collar 66 circumscribes the cylinder 10 and has a pair of diametrieally opposed journals 68 formed thereon. The tie rods are substantially one-half the length of the motor and are provided with nuts 72 at their outer ends and are threadedly affixed to the collar 66 at their inner ends. Thus, the motor of this embodiment may be assembled in a fashion similar to that described above, and the heads 12 and 14 may be angularly disposed in the desired relationship to the journals 68 prior to tightening of the nuts '72 to complete the assembly.

The embodiment of FIG. 5 illustrates a mounting plate 74 which may be used to mount an expansible chamber motor at right angles to the mounting surface. In this embodiment the mounting plate 74 is similar to the plate 24 except that no feet are formed thereon and holes 75 are threaded to receive tie rods 28. The dimensions of the plate 74 are sufficient to provide for mounting holes 76 whereby the piston rod 32 may extend through a hole defined in the mounting surface and bolts extending through the holes 76 affix the plate to the mounting surface. It will be appreciated that in a like manner this type of mounting plate could be applied to the end of the motor remote from the piston rod.

Another embodiment of the invention is illustrated in FIG. 6 wherein the mounting plate has means ailixed thereto to mount the motor for a swivel movement. In this embodiment, the mounting plate 78 issimilar to that of plate 22 of FIG. 1, except that the feet 36 and the tie rods 28 are threaded into the plate. A pair of parallel projections or bosses 80 extend from the plate '78 in spaced relation, and a swivel pin 82 is interposed between the bosses 80 by insertion of the pin into bores 84 defined therein. The pin 82, thus, is intended to cooperate with a bearinged support hole, not shown, which provides the support for the motor.

It will, thus, be appreciated that the invention may be employed wtih a plurality of expansible chamber motor mounting means, and that any of the disclosed mounting means may be easily employed with standard cylinder and head elements.

It is understood that various embodiments of the invention, other than those illustrated, may be apparent to those skilled in the art without departing from the spirit and scope of the invention, and it is intended that the invention be defined only by the following claims.

I claim:

1. An expansible chamber motor comprising in combination, a tubular cylinder having opposite open ends, a head sealingly engaging each end of said cylinder, said heads being rotatably positionable with respect to said cylinder and each other, a piston within said cylinder, a piston rod afiixed to said piston and extending through one of said heads, a sealing gland circumscribing said piston rod and received within a recess defined in the head the rod passes through, a port defined in each of said heads communicating with the interior of said cylinder, a plate engaging each of said heads in opposed relation to said cylinder, a bore defined in the plate engaging the head the piston rod passes through receiving said piston rod, a shoulder defined on the bored plate cooperating with said packing gland, said plates being rotatably positionable with respect to said heads and a plurality of tie members interconnecting said plates whereby tensioning of said tie members maintains said plates in assembled relation on said heads and said gland within the associated head and said heads in assembled relation on said cylinders.

2. In an expansible chamber motor as in claim 1 wherein motor mounting means are aifixed to at least one of said plates.

3. An expansible chamber motor comprising in combination, a tubular cylinder having opposite open ends, a head sealingly engaging each end of said cylinder, said heads being rotatably positionable with respect to said cylinder and each other, a piston within said cylinder, a piston rod afiixed to said piston and extending through one of said heads, a port defined in at least one of said heads in communication with the interior of said cylinder, a plate engaging each of said heads in opposed relation to said cylinder, said plates being rotatably positionable with respect to said heads, an annular collar circumscribing said cylinder intermediate said heads, a pair of journals mounted on said collar in opposed diametrical relation, tie members afiixed to said collar and connected to said plates whereby tensioning of said tie members draws said plates toward each other maintaining said plates, heads and cylinder in assembled relation.

4. An expansi ble chamber motor comprising in combination, a tubular cylinder having opposite open ends, a head sealingly engaging each end of said cylinder, said heads being rotatably positionable with respect to said cylinder and each other, a piston within said cylinder, a piston rod aflixed to said piston and extending through one of said heads, a port defined in at least one of said heads in communication with the interior of said cylinder, a plate engaging each of said heads in opposed relation to said cylinder, said plates being rotatably positionable with respect to said heads, a plurality of tie rods interconnecting said plates whereby tensioning said tie rods simultaneously maintains said plates in assembled relation on said heads and said heads in assembled relation on said cylinder, a packing gland mounted in the head through which the piston rod extends establishing a seal between said rod and associated head, a bore defined in the plate engaging said last mentioned head permitting said rod to pass therethrough and means defined on said bored plate engaging said gland maintaining said gland in the associated head upon tensioning of said tie rods.

5. An expansible chamber motor comprising, in combination, a tubular cylinder having opposite open ends, a head within and enclosing each end of said cylinder, said heads including an annular radially extending shoulder abuttingly engaging the associated cylinder end and seal means sealingly associating with said cylinder, said heads being rotatably associated With said cylinder and each other, a piston within said cylinder, a piston rod affixed to said piston and extending through one of said heads, a plate engaging each of said heads remote from said head shoulders and rotatably positionable with respect to the associated head, a plurality of tie rods interconnecting said plates whereby tensioning of said tie rods simultaneously maintains said plates in assembled relation on said heads and said heads in assembled relation upon said cylinder, and a radially extending port defined in at least one of said heads intermediate the plate and shoulder associated therewith and in communication with the interior of said cylinder.

6. In an expansible chamber motor as in claim 5 Wherein one of said plates radially extends substantially beyond the configuration of the cylinder on opposite sides thereof and mounting holes defined in said one plate radially beyond the cylinder configuration.

7. In an expansible chamber motor as in claim 5 wherein a port is defined in each of said heads in communica tion with the interior of said cylinder.

References Cited in the file of this patent UNITED STATES PATENTS 2,410,808 Christensen Nov. 12, 1946 2,426,108 Loewe Aug. 19, 1947 2,493,602 Sterrett Jan. 3, 1950 2,719,766 Densmore Oct. 4, 1955 2,890,917 Prince June 16, 1959

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