US2123587A - Detachable counterbalance - Google Patents

Description

July 12, 1938. I HQLZER 2,123,587

DETACHABLE COUNTERBALANCE Filed Nov. 6, ,1935 2 Sheets-Sheet 1 44 H/ra A. ho/zer:

ATTo'RNEY Patented July 12, 1938 UNITED STATES PATENT ()FFICE Hiram A. Holzer, Pittsburg, Kans.,

one-half to United assignor of Iron Works Company,

Pittsburg, Kans., a corporation of Kansas, and

one-half to J. A. Werme, doing business as J. A. Werme Steel and Iron Works, Oklahoma City, Okla.

Application November 6, 1935, Serial No. 48,486

8 Claims.

This invention relates to a crank such as used for actuating the walking beam of a well pumping unit, and particularly to one of that character equipped with a weight element for counterbalancing weight of the pump rods. In cranks of this character it is necessary to disconnect the counter-balance when the pumping rods are disconnected and the unit is used in well cleaning or similar well maintenance operations, in order to allow the crank to rotate free of the weight. In present deep wells it is common that these counter-balances weigh as much as 6,000 pounds, consequently their connection and disconnection with a crank is a difficult matter. It is, therefore, the principal object of the present invention to provide a crank and counter-balance construction wherein the counter-balance may be readily connected with or disconnected from the crank. It is also an important object of the invention to provide a secure connection between the crank and counter-balance with a minimum number of fastening points.

In accomplishing these and other objects of the invention, hereinafter pointed out, I have provided improved details of structure the preferred form of which is illustrated in the accompanying drawings wherein:

Fig. 1 is a perspective view of a portion of a well pumping unit equipped with a crank embodying the features of the present invention.

Fig, 2 is a side elevation of a portion of the unit particularly illustrating the crank and counter-balance weight therefor at the lowermost point of crank travel.

Fig. 3 is an end elevational View of the crank and counter-balance weight.

Fig. 4 is a section through the weight and the free end of the crank on the line 4-4 of Fig. 3, showing the counter-balance in disconnected position.

Fig. 5 is an enlarged section through the counter-balance and crank on the line 5-5 of Fig. 2.

Fig. 6 is a similar section on the line 6-6 of Fig. 2.

Fig. 7 is a detail perspective View of the parts of the counter-balance, and free end of the crank, shown in disassembled spaced relation.

Referring more in detail to the drawings:

I designates a well pumping unit of any standard type, but here illustrated as including a reduction mechanism indicated by the housing 2, in which are journaled power input and output shafts 3 and 4 respectively, the respective shafts being interconnected by any suitable reduction gear, not shown. The power input shaft may be operated by a suitable prime mover, not shown, that is operably connected therewith by means of a belt 5 operating over a pulley 6 fixed to a projecting end of the shaft 3. Mounted on one end of the output shaft'4 is a crank l carrying a wrist pin 8, to which is connected a pitman 9 for operating a walking beam (not shown), to the outer end of which is connected the well pumping rods as in conventional practice. The pumping unit is mounted adjacent the well on parallel sills l0 and II carried upon a foundation I2, having a recess 13 therein, to provide clearance for rotation of a counter-balance l4 that is connected with the crank as later described.

When the well is in operation, the crank i and counter-balance weight M are gyrated about the axis of the shaft 4 to reciprocate the walking beam by means of the pitman 9, the weight and position of the counter-balance being such that when the rods are being lifted the crank and counter-balance are being moved downwardly from top to bottom dead center of the crank, and when the rods are moving downwardly in the well the crank and counter-balance are being moved from bottom toward top dead center of the crank. The counter-balance weight thus balances the weight of the rods to reduce the power required in operating the pumping unit, and to provide for smooth and steadier operation of the beam.

In present deep wells the string of pumping rods suspended from the free end of the walking beam are of such heavy weight that weight must be added to the crank in the form of the counterbalance -M, in order to substantially balance the weight of the rods. It is the practice, when cleaning the well and performing other maintenance operations, to use the pumping unit for running the sand pump, bailer or other tools, and it is necessary to remove the counter-balance for the reason that weight of the counter-balance is greatly in excess of the load of the tools.

Owing to the fact that these counter-balances are of such heavy weight, they are difiicult to remove from and apply to the crank. I have, therefore, provided a crank and counter-balance construction wherein the counter-balance may be readily attached to or disconnected from the crank with a minimum effort, as now to be described.

The crank 1 includes a split hub l5, provided with a bore I 6 to receive the shaft 4. The hub is keyed by a spline I1, and tightly clamped about the shaft by bolts [8 extending through aligning ears l9 and 20 on opposite sides of the split portion of the hub, as best shown in Fig. 2. Extending radially from the hub |5 is an arm 2| terminating in a T-shaped head 22, having an arcuate outer face 23' formed on the radius of an arc coinciding with the circle of gyration generated by the rotated crank. The inner or chord side of the head extends beyond the sides 24 and 25 of the arm to form shoulders 26 and 21, adapted to be engaged by clamp elements, later described. The outer and inner faces of the arm are provided with bosses 28 and 29, having a plurality of'transverse openings 36 extending therethrough to adjustably mount the wrist pin 8, to which is connected the pitman 9 in any conventional manner.

The counter-balance includes a base member 3| of substantially greater length than the head 22, and has an inner arcuate face 32 formed on the same radius as the face 23 of said head. The opposite face 33 of the base extends in a flat plane at a spaced tangent to the arcuate face 32. The ends of the base have bevelled corners 34 and 35, carrying bosses 36 and 31 having openings 38 and 39 extending therethrough, and through the ends of the base, to accommodate bolts 46 and 4| for attaching a'capmember 42. The cap member 42 has a flat face 43 that cooperates with the fiat face 33 to clamp therebetween a plurality of liners 44, later described.

The opposite face of the cap section is also formed on an arc concentric with the shaft 4, and has openings 45 and 46 aligning with the openings 38 and 39 in the ends of the base memher, the openings 45 and 46 being counter-bored, as at 41 and 48, to accommodate the heads 49 of the bolts 40 and 4|, that have their shanks extending through the aligning openings for projection through the bosses 36 and 31 to mount nuts 56 and 5|.

The liners 44 each comprises paired bars 52 and 53 conforming in width to the cap and base members, and are of such length that when placed end to end their outer ends will align with the ends of the cap and base members, as shown in Fig. 2. Each liner section has upper and lower side ribs 54 and 55, machined in flat plane so that the ribs of one liner will closely engage the machined face of the rib of the adjacent liner. The outer ends of the liner bars have slots 56, through which the shanks of the bolts 4| are extended to hold the outer, ends of the liners in alignment with the ends of the cap and base members. The inner ends of the liner bars are provided, on their lower faces, with lugs 51 adapted to engage in recesses 58 in the upper facesof corresponding outer bars, as best shown in Fig. 5. The flat face of the base section is also provided with similar lugs to engage in the recesses of the uppermost liner sections, and the flat face of the cap member is provided with similar recesses for accommodating the lugs of the outermost liner sections. The lugs and recesses thus cooperate with the bolts to retain the liners in position between the base and cap members.

The inner face of the base member is provided with elongated recesses 59 and 6D, terminating at their inner ends in enlarged sockets 6| and 62 for accommodating the hubs 63 and 64 of C- clamps 65 and 66, the hubs of the C-clamps being rotatably anchored in the sockets by pins 61 and 68, extending through aligning openings 69 in the sides of the base member and through openings 10 in the hubs, as best shown in Fig. 6, the heads H of the pins being counter-sunk as at I2, in the outer side face of the base section. The clamps illustrated, in-

clude substantially C-shaped arms having their free ends 13 and 14 terminating in cylindrical heads 15 and 16 adapted to overlie the shouldered portions of the crank head when they are moved into engaged position with the crank, as shown in Fig. 2. The ends of the crank head are slotted, as at H and 18, to accommodate the arms of the clamps when they are moved to clamping position.

Threadedly mounted in the heads 15 and 16 are jack screws 19 and 80, having heads 8| by which the screws may be rotated to thread the shanks thereof against the shoulders of the head and into sockets 82 and 83 that are formed therein on opposite sides of the longitudinal center line of the crank arm, as shown in Fig. 4. Attention is here directed to the fact that the pivotal connections of the clamps with the counterbalance are spaced apart a greater distance relatively to the extended center line of the crank arm than the spacing of the sockets 82 and 83 so that the jack screws 19 and 89 pass the upper dead center position relative to the pivotal mounting of the clamps respective sockets, thereby providing an automatic lock for the clamps to prevent retractive pivotal movement when the counter-balance is drawn against the arcuate head of the crank arm. against lateral movement with respect to the crank, the arcuate faces of the base and the head of the crank are provided with registering notches 84 and 85 for accommodating a key 86. The key 86 is preferably provided with a head 81 (Fig. 5), having a lug portion 88 for engaging in a socket 89 in the bottom of the notch 84, to lock the key against lateral movement relatively to the base member of the counter-balance. The

key may also be provided with a threaded socket 96 to aid in its removal from the counter-balance.

In assembling the counter-balance and crank, a suitable number of liners are assembled to add sufficient weight for completing counter-balance of the rods in the well. applied to the uppermost liner, and the bolts 46 and 4| are extended through the aligning openings in the cap and base members, and through the notches formed in the ends of the liners, after which the nuts 50 and 5| are applied to the bolts to draw the base and cap members together. The liners are so assembled that the ends thereof are supported in abutting relation with the lugs of one liner engaging within the recesses of the adjacent liner, and i.

with the lugs and recesses in the outermost liners engaging respectively the recesses and lugs of the base and cap members, as shown in Fig. 4. The C-clamps are then fixed to the base member by inserting them in the sockets 6| and 62, and

extending the pins 61 and 68 through the openings 69 and through the openings 10 in the hubs of the clamps. The recesses 59 and 6|] are of sufficient length and depth to allow substantially complete retraction of the clamps therein when the counter-balance is disconnected from the crank, as shown in Fig. 4. In this position the crankis free to rotate over the counter-balance without striking the counter-balance.

To connect the counter-balance with the crank, the crank is moved to bottom dead center to align with the counter-balance, as shown in Fig. 4, after which the key 86 is inserted and the C-clamps moved into engagement with the when they engage in the In order to lock the counter-balance The base member is then l 51 crank, so that the heads 15 and i6 align with the sockets 82 and 83 in the shoulders 26 and 2'17.

The jack screws are then threaded downwardly into the sockets to cause the counter-balance to be drawn into engagement with the head of the crank. When the arcuate faces of the crank head and counterbalance base are drawn into firm contact with each other the jack screws are locked in position by means ,of jamb nuts 9!, then when the crank is rotated the counterbalance will be carried therewith to balance the Weight of the rods.

When it is found necessary to disconnect the counter-balance, the crank is moved to bottom dead center, after which the jamb nuts are slackened and the jack screws rotated to allow the counter-balance to be lowered into engagement with its support on the foundation. As soon as the counter-balance is supported on the foundation, and the ends of the jack screws have cleared the shoulders 26 and 21, the C-clamps are swung backwardly so that they lie within the recesses 59 and 69 formed in the upper face of the base section, as shown in Fig. 4, In this position the crank will rotate freely of the counter-balance.

From the foregoing, it is obvious that I have provided a counter-balanced crank construction whereby the counter-balance element may be readily applied to or removed from the crank in a simple and efficient manner.

What I claim and desire to secure by Letter Patent is:

1. In combination with a crank arm having jack screw engaging shoulders at opposite sides of the longitudinal center of said arm, a counterbalance, clamp members, pivot members pivotally connecting the clamp members with the counterbalance and located at greater lateral distances from the extended center line of said arm than the spacing of said engaging shoulders and whereon said clamp members are adapted to swing to and from said shoulders, and jack screws threadedly carried by the clamp members and engageable with said shoulders when the clamp members are moved toward said shoulders to lock the clamp members from lateral pivotal movement in a direction away from said crank arm and to draw the counterbalance into engagement with said crank arm when the jack screws are threaded against said shoulders.

2. In combination with a crank arm having jack screw engaging shoulders at opposite sides of the longitudinal center of said arm, a counterbalance, clamp arms, pivot members pivotally connecting the clamp arms with the counterbalance and located at greater lateral distances from the center line of said crank arm than the spacing of said engaging shoulders and whereon the clamp arms are swingingly movable away from said shoulders, jack screws threadedly carried by the clamp arms and having ends engageable with said engaging shoulders when the clamp arms are swung toward said shoulders to lock the clamp arms from lateral pivotal movement in a direction away from said crank arm and to draw the counterbalance into engagement with' said crank arm when the jack screws are threaded against said shoulders, and key means connecting the crank arm with the counterbalance for cooperating with the clamp arms and jack screws to further prevent shifting movement of the counterbalance relatively to the crank arm.

3. In combination with a crank arm including a head member having laterally extending shoulders provided with jack screw engaging portions and open ended slots, a counterbalance, clamp arms swingingly movable through said slots, pivot members pivotally connecting the clamp: arms with the counterbalance and located at greater lateral distances from the center line of said arm than the spacing of said jack screw engaging portions, and jack screws carried by the clamp arms and engageable with said engaging portions of theshoulders to lock said clamp arms from lateral pivotal movement in directions away from said crank arm and to draw the counterbalance into engagement with said arm when the jack screws are threaded against said shoulders.

4. In combination with a crank arm including a head member having inwardly facing shoulders extending laterally from said arm provided with sockets in their inner faces and laterally open ended slots, a counterbalance including a base member adapted to engage the crank arm, clamp members on said base member including body portions adapted to seat in the slots in the head member of the crank arm and having heads adapted to overlie the inner faces of the shoulders on the crank arm head member in inwardly spaced relation to said slots, and jack screws on the clamp heads adapted to seat in the sockets in said shoulders to lock the counterbalance to the crank arm.

5. In combination with a crank arm including a head member having inwardly facing shoulders extending laterally from said arm provided with sockets in their inner faces and laterally open ended slots, a counterbalance including a base member adapted to engage the crank arm, C- shaped clamp members each pivotally mounted at one end on said base member having body portions adapted to seat in the slots in the crank arm head member and having inwardly extended heads adapted to overlie the inner faces of the shoulders on the crank arm head member at opposite sides thereof, and fastening means on the heads of the clamp members engageable in said shoulder sockets to lock the counterbalance to the crank arm.

6. In combination with a crank arm including a head member having inwardly facing shoulders extending laterally from said arm provided with sockets in their inner faces and laterally open ended slots, a counterbalance including a base member adapted to engage the crank arm, clamp members on said base member including body portions adapted to seat in the slots in the head member of the crank arm and having heads adapted to overlie the shoulders on the crank arm head member in inwardly spaced relation to said slots, and jack screws on the clamp heads adapted to seat in the sockets in said shoulders, the crank arm and said base member having registering slots and a key fitting said slots to lock the base member against lateral movement relative to the crank arm.

7. In combination with a crank arm including an arcuate head at its outer end provided with shoulders on the chord side of said arcuate head having sockets and laterally open ended slots, a counterbalance including a base member adapted to engage the crank arm head having recesses in its inner face at opposite sides of its longitudinal center terminating in sockets, clamp members including hubs pivotally mounted in the sockets of said base member and having body portions adapted to lie in said recesses when idle and adapted to seat in said slots in said arcuate head,

the clamp members having portions adapted to overlie the shoulders on said arcuate head when in functional position, and jack screws on said overlying portions adapted to seat in the sockets of said shoulders to lock the counterbalance to the crank arm.

8. In combination with a crank arm including a head member having inwardly facing shoulders extending laterally from said arm and having 10 laterally opening slots, a counterbalance, 0-

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