US2986948A - Pump jack - Google Patents

Description

2 Sheets-Sheet 1 James 5} Jen sen J. B. JENSEN June 6, 1961 PUMP JACK Filed Aug. 29, 1958 J. B. JENSEN June 6, 1961 PUMP JACK 2 Sheets-Sheet 2 Filed Aug. 29, 1958 lllllll I mdfl fi w w H a m 0 I $1,: zK/ i 1 3 7 4 7 i A I 5 3 N 1 1 9 l 1 James 5, Jensen INVENTOR.

2,986,948 PUMP JACK James B. Jensen, 14th and Pacific Sts., Colfeyville, Kans. Filed Aug. 29, 1958, Ser. No. 758,093

Claims. (CI. 74-50) The present invention relates to pump jacks and more particularly to pump jacks adapted to convert rotary motion to reciprocatory motion for the purpose of imparting reciprocatory motion to a reciprocable polish rod of a pump.

It is an object of the present invention to provide a pump jack having a minimum of parts.

Another object of the present invention is the provision of a pump jack which will be of desirably compact size and structural arrangement.

A further object of the present invention is the provision of a pump jack in which the parts coact in a novel structural relationship so as to reduce the number of hearing surfaces and supporting elements.

Finally, it is an object of the present invention to provide a pump jack which will be simple and inexpensive to manufacture, easy to assemble, disassemble, repair and maintain, and rugged and durable in use.

Broadly, these objects are achieved by providing a pump jack which is essentially a sandwich of four parts. The two outer parts are halves of the pump jack housing and the two inner parts are a rotor and a crosshead to which reciprocatory movement is imparted by the rotor. The two inner parts are supported entirely by bearing contact with each other and with the two housing halves.

Other objects, features and advantages of the present invention will become apparent from a consideration of the following description, taken in connection with the accompanying drawings, in which:

FIGURE 1 is a perspective view of the exterior of a pump jack according to the present invention, shown in its operative environment including the polish rod of a reciprocatory pump;

FIGURE 2 is a fragmentary perspective view showing the bearing interrelationships of the crosshead and th cover plate of the pump jack housing;

FIGURE 3 is a cross-sectional view taken on the line 3-3 of FIGURE 4; and

FIGURE 4 is an elevational view of the present invention with the cover plate removed and with various operational positions of the parts shown in full line and in phantom line, the full line representation showing the parts during the up stroke.

Referring now to the drawings in greater ,detail, there is shown a pump jack indicated generally at 1 adapted to impart reciprocatory movement to the polish rod 3 of a reciprocatory pump (not shown). The pump jack comprises a housing 5 made up of a base portion 7 to which a cover plate 9 is detachably secured by means of bolts 11. Base portion 7 has a bearing boss 13 in which is mounted for rotation a pinion gear stub shaft 15 having a pinion gear 17 on its inner end within housing 5. On its outer end, outside housing 5, shaft 15 carries a V pulley 19 which is keyed thereto and which is driven by an endless V belt 21 by means of a smaller V pulley on the drive shaft of an electric motor or other drive means (not shown).

The gear teeth of pinion gear 17 are in mesh with peripheral gear teeth 23 on a circular rotor 25. Rotor 25 has an axial hub 27 which has a cylindrical outer contour and which is mounted for rotation in a hollow generally cylindrical sleeve 29 which is integral with the remainder of, and comprises a portion of, base portion 7 of housing 5. In the embodiment shown, sleeve 29 provides spaced cylindrical bearing surfaces in bearing con- States Patent tact with the cylindrical outer contour of hub 27; and it will of course be appreciated that the over-all configuration of sleeve 29 is immaterial so long as it provides cylindrical bearing surfaces suitable to provide radial support in all directions for hub 27 and hence for rotor 25 as a whole. Likewise, it is immaterial whether sleeve 29 is integral with base portion 7.

At its inner end, sleeve 29 has annular bearing surfaces 31 which are in bearing contact with complementary annular bearing surfaces 33 formed on an annular abutment shoulder of rotor 25. In the illustrated embodiment, the bearing surfaces 31 and 33 are uniplanar in a plane perpendicular to the axis of rotation of rotor 25; but it will of course be understood that they could be conical about the axis of rotation of the rotor or have other shapes provided only that these surfaces be disposed at a substantial angle to the axis of rotation of the rotor and that the generatrices of these surfaces rotate about an axis coincident with the axis of rotation of rotor 25. In this way, sleeve 29 provides radial bearing support for rotor 25 in all directions and axial bearing support for rotor 25 in one axial direction. Of course, it will be understood that the use of ball hearings or roller bearings or other anti-friction devices or the like between rotor 25 and base portion 7 does not alter the essential operative characteristics of the bearing structure between these two members; but a highly desirable feature of the preferred embodiment of the present invention is that such auxiliary bearing devices are unnecessary.

Also mounted in housing 5, but for rectilinear reciprocatory movement, is a crosshead 35. Crosshead 35 includes a pair of spaced guide members 37 and 39 which have confronting, generally parallel track surfaces 41 and 43 thereon, respectively. Rotor 25 has a bearing boss 45 disposed eccentrically thereon which carries a crank pin 47. Crank pin 47 is comprised of three parts: a short axle 49 which is mounted in bearing boss 45 and the axis of which is parallel to the axis of rotation of rotor 25; a roller 51 mounted for rotation on an end of axle 49 on the crosshead side of bearing boss 45; and a retaining nut 53 on a screw-threaded end of axle 49 on the opposite side of bearing boss 45. The roller of crank pin 47 is disposed between and has rolling contact with track surfaces 41 and/or 43 in all positions of rotor 25 and crosshead 35 relative to each other, as seen in FIGURE 4. Thus, track surfaces 41 and 43 define between them a slot within which crank pin 47 moves.

Rotor 25 and crosshead 35 have bearing contact with each other in all positions. To this end, rotor 25 is provided with an annular abutment flange 55 which carries on its crosshead side a uniplanar bearing surface of which the plane is perpendicular to the axis of rotation of rotor 25. Spaced guide members 37 and 39, in turn, carry on their rotor side spaced uniplanar bearing surfaces which are also perpendicular to the axis of rotation of rotor 25 and which are in bearing contact with substantial areas of the coacting bearing surfaces of flange 55 of rotor 25 in all positions of rotor 25 and crosshead 35. For this reason, flange 55 of rotor 25 is made of as great a diameter as possible so as to provide as great contact bearing areas with crosshead 35 as possible and to assure that the spaced areas of contact will be spaced apart by distances as great as possible so as to assure the greatest stability of the contacting parts 25 and '35. It will of course be appreciated that flange 55 need not be annular in order to achieve this result. Instead, flange 55 could have a variety of closed configurations other than circular, or could be in the form of an enlarged bearing boss covering the area which includes the axis of rotation of rotor 25; but the annular configuration of flange 55 is preferred not onlyfor ease and precision of manufacture but also for the uniform precision of operation which is available with this configuration. It will also be observed that hearing boss 45 could be positioned at a variety of distances radially of the axis of rotation of rotor 25; but it is preferred that this boss be bisected by annular flange 55 so that the bearing surface of the flange is a uniplanar continuation of the bearing surface between boss 45 and roller '51 so as to enable accurate positioning of roller 51. From a consideration of the arrangement just described, it will be evident therefore that crosshead 35 provides axial support for rotor 25 in one direction and that bearing surfaces 31 of sleeve 29 of housing 5 provide axial support for rotor 25 in the other direction, so that sleeve 29 and crosshead 35 provide the sole support necessary to retain rotor 25 accurately in its operative position.

Crosshead 35 also includes a pair of spaced parallel stabilizer members 57 and 59 which are disposed at a substantial angle to track surfaces 41 and 43, preferably 90. The stabilizer members extend across and bridge between spaced guide members37 and 39 and maintain the latter in accurately spaced relationship with a minimum of parts. As also seen in FIGURE 3, members 57 and 59 are on one side of guide members 37 and 39, and thus leave the entire confronting surfaces of members 37 and 39 comprising track surfaces 41 and 43 available for rolling contact with roller. 51.

In addition to spacing apart guide members 37 and 39, stabilizer members 57 and 59 perform the function of confining the reciprocatory movement of crosshead 35 to a rectilinear path. For this, purpose, stabilizer members 57 and 59 are provided with confronting guide surfaces 61 and 63, respectively, and an elongated rib 65 on the interior of cover plate 9 has corresponding guide surfaces with which guide surfaces 61 and 63 are in slidable bearing contact. Also, stabilizer members 57 and 59 are provided with guide surfaces 67 and 69 which have slidable bearing contact with corresponding guide surfaces on rib 65 of cover plate 9. Thus, guide surfaces 61 and 63 coact with corresponding guide surfaces on the cover plate to restrain crosshead 35 to a rectilinear path of movement, while guide surfaces 67 and 69coact with corresponding guide surfaces on the cover plate to prevent displacement of crosshead 35 in any direction having a component along the axis of rotation of rotor 25. In the illustrated embodiment, guide surfaces 6'1 and 63 are shown to be parallel to each other, while guide surfaces 67 and 69 are shown to be coplanar with each other and perpendicular to surfaces 61 and 63. However, it will be apparent that the various bearing surfaces shown could be reduced in number, as by replacing sur faces 61 and 67 with a single inclined surface and by replacing surfaces 63 and 69 by a single inclined surface. Thus, the essential operative relationships of the interengaged bearing surfaces of crosshead 35 and cover plate 9 are that there be at least two bearing interfaces, at least one of which must be at a substantial angle to the axis of rotation of rotor 25 so as to hold crosshead 35 against rotor 25, and at least two of which must be disposed at substantial angles to a plane perpendicular to the axis of rotation of rotor 25 so as to confine crosshead 35 to a rectilinear path of movement. The first interface may be one of the two latter interfaces; and it is not necessary that the interfaces be planar or spaced apart, as they could be defined by a continuous arcuate interface. It is necessary, however, that the interfaces between crosshead 35 and cover plate 9 have uniform cross-sectional configurations in planes perpendicular to the line of movement of crosshead 35 over a substantial distance.

In the embodiment shown, rib 65 on cover plate 9 is disposed between stabilizer members 57 and 59 of crosshead 35. .A possible alternative construction is that a rib on crosshead 35 be disposed between a pair of spaced parallel ribs on cover plate 9, but this alternative is less preferred than that shown, as the provision of spaced stabilizer members '57 and 59 lends the greatest strength and rigidity to crosshead 35 with the least weight.

In this connection, it is important to note that the location of members 57 and 59' across the ends of members 37 and 39 also lends stability to the assembly during the up or working stroke, as roller 51 is then roughly in line with members 57 and 59 and does not tend to cant them in their guides. During the down stroke, roller 51 is in a position to cant crosshead 35 but does not as the load is relatively very small.

It will therefore be apparent that the position of crosshead 35 axially of rotor 25 is fixed by its bearing contact with and between rotor 25 and cover plate 9 and that the position of crosshead 35 along its path of rectilinear movement perpendicular to the axis of rotor 25 is fixed by the rotated position of crank pin 47 In all non-vertical positions of track surfaces 41 and 43, at least a portion of the weight of crosshead 35 and the members carried thereby will be borne by crank pin 47; and hence, a counterweight 71 is secured to the end of hub 27 of rotor 25 by a bolt 73 in diametric opposition to crank pin 47.

As seen in FIGURES 1 and 4, the upper ends of stabilizer members 57 and 59 are housed within an extension of housing 5 comprising an elongated cover 75 having a longitudinally extending slot 77 through the side wall thereof. Cover 75 is of sheet metal detachably forcefitted on a corresponding adaptor portion of housing 5. The upper ends of stabilizer members 57 and 59 carry between them a bracket 79 which coacts with a detachable clamp 81 to secure polish rod 3 in unitary assembly with and parallel to stabilizer members 57 and 59 and in parallelism to the path of rectilinear movement of crosshead 35. To this end, bracket 79 extends outside housing 5, and specifically outside cover 75 through slot 77.

The operation of the device of the present invention is that upon rotation of power driven pinion gear 17, rotor 25 is driven to rotate about its axis and crank pin 47 moves in a circular orbit within the slot defined between track surfaces 41 and 43 of crosshead 35. Crosshead 35- is thus reciprocated along the path defined by its bearing contact with cover plate 9, thereby to reciprocate the unitary polish rod of the pump to be driven.

To assemble the device, with the pinion gear 17 already in place and with cover plate 9 removed, it is necessary only to insert rotor 25 with teeth 23 in mesh with those of pinion gear 17 and with hub 27 in sleeve 29. Counterweight 71 can be attached at this or any later stage. Next, crosshead 35 is inserted with track surfaces 41 and 43 on either side of crank pin 47; and finally, cover plate 9 is laid on the assembly with rib 65 between stabilizer members 57 and 59. The tightening of bolts 11 completes the assembly of the jack proper. Cover 75 is then added, and the securement of polish rod 3 on bracket 79 by means of clamp 81 completes the assembly.

It will be seen that a very compact and simple structural arrangement is provided in which the rotor and the crosshead are maintained in assembled relationship by hearing contact with each other and with the two housing halves. Thus, there are three critical bearing relationships: that between the rotor and the base portion of the housing, that between the rotor and the crosshead, and that between the crosshead and the cover plate. To summarize these relationships, a bearing surface between the base portion of the housing and the rotor must be disposed at a substantial angle to the axis of rotation of the rotor and the generatrix of this surface or generatrices of these surfaces must have an axis of rotation coincident with that of the rotor. The bearing surfaces between the rotor and the crosshead must be uniplanar in a plane perpendicular to the axis of rotation of the rotor. The hearing surfaces between the crosshead and the cover plate must be at least two in number and must include at least one disposed at a substantial angle to the axis of rotation of the rotor and at least two disposed at a substantial angle to a plane perpendicular to the axis of rotation of the rotor.

From a consideration of the foregoing disclosure, it will be obvious that all of the initially recited objects of the present invention have been achieved.

Although the present invention has been described and illustrated in connection with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit of the invention, as those skilled in this art will readily understand. Such modifications and variations are considered to be within the purview and scope of the present invention as defined by the appended claims.

What is claimed is:

1. For use with a pump having a reciprocable drive element, a pump jack comprising a housing having a base portion and a cover plate detachably secured to the base portion, the base portion having a hollow generally cylindrical sleeve extending therethrough, the sleeve having an inner end disposed within the housing, a rotor having an axial hub mounted for rotation in the sleeve, the rotor and the inner end of the sleeve having interengaged bearing surfaces disposed at a substantial angle to the axis of rotation of the rotor, said surfaces having generatrices that rotate about said axis, a crank pin mounted on the rotor a substantial distance from the axis of rotation of the rotor, a crosshead mounted for reciprocatory movement in the housing, the rotor and the crosshead having interengaged uniplanar bearing surfaces lying in a common plane perpendicular to said axis of rotation, the crosshead having a slot in which the crank pin is disposed, the slot being disposed at an angle to the direction of reciprocatory movement of the crosshead, the crosshead and the cover plate having interengaged bearing surfaces disposed at a substantial angle to said axis of rotation and said common plane, the last-named bearing surfaces being defined by an infinite number of straight lines parallel to each other and to a line perpendicular to said axis of rotation, drive means for rotating the rotor, and a bracket carried by the crosshead and adapted to be detachably secured to a reciprocable drive element of a pump.

2. For use with a pump having a reciprocable drive element, a pump jack comprising a housing having a base portion and a cover plate detachably secured to the base portion, a rotor mounted for rotation in the housing on the base portion about a horizontal axis, a crank pin mounted on the rotor a substantial distance from the axis of rotation of the rotor, a crosshead mounted for vertical reciprocatory movement in the housing, the crosshead having a pair of horizontally disposed, vertically spaced-apart members defining between them a horizontal slot in which the crank pin is disposed, a pair of elongated spaced parallel vertical slide members rigidly interconnecting said horizontal members on the side of said horizontal members opposite the rotor, the cover plate having a guide portion disposed between said vertical slide members, said guide portion and vertical slide members having interengaged vertical bearing surfaces disposed at a substantial angle to said axis and to a plane perpendicular to said axis, drive means for rotating the rotor, and a bracket carried by said vertical slide members and adapted to be detachably secured to a reciprocable drive element of a pump. a

3. Apparatus as claimed in claim 2, the crank pin when rising being disposed on one side of the vertical plane in which said axis lies, and the vertical plane which is midway between said vertical slide members and parallel to said vertical plane in which said axis lies being on said one side of said vertical plane in which said axis lies, the said vertical slide member farthest from said axis being at least as far from said axis as the crank pin.

4. For use with a pump having a reciprocable drive element, a pump jack comprising a housing having a base portion and a cover plate detachably secured to the base portion, a rotor mounted for rotation in the housing on the base portion about a horizontal axis, a crank pin mounted on the rotor a substantial distance from the axis of rotation of the rotor, a crosshead mounted for vertical reciprocatory movement in the housing, the crosshead having a slot in which the crank pin is disposed, the slot being disposed at an angle to the direction of reciprocatory movement of the crosshead, drive means for rotating the rotor, and a bracket carried by the crosshead and adapted to be detachably secured to a reciprocable drive element of a pump, the crank pin when rising being disposed on one side of the vertical plane in which said axis lies, and the bracket being also disposed on said one side of said vertical plane.

5. For use with a pump having a reciprocable drive element, a pump jack comprising a housing having a base portion and a cover plate detachably secured to the base portion, a rotor mounted for rotation in the housing on a shaft extending through the base portion about a. horizontal axis, a crank pin mounted on the rotor a substantial distance from the axis of rotation of the rotor, a crosshead mounted for vertically reciprocatory movement in the housing, the crosshead having a slot in which the crank pin is disposed, the slot being disposed at an angle to the direction of reciprocatory movement of the crosshead, drive means for rotating the rotor, a bracket carried by the crosshead and adapted to be detachably secured to a reciprocable drive element of a pump, and a counterweight fixed to the shaft outside the housing and having its center of gravity a substantial distance from said axis directly opposite the crank pin relative to said axis.

References Cited in the file of this patent UNITED STATES PATENTS 923,644 Griggs June 1, 1909 1,403,632 Recen Jan. 17, 1922 1,449,785 Selby Mar. 27, 1923 1,451,691 Frederick Apr. 17, 1923 1,867,307 Carpenter July 12, 1932 2,055,041 Miller Sept. 22, 1936 2,301,967 Mosker et al. Nov. 17, 1942 2,677,966 Mueller May 11, 1954 2,699,745 Ayres Jan. 18, 1955 2,704,941 Holford Mar. 29, 1955 FOREIGN PATENTS 435,386 France Dec. 23, 1911

Images