US1615940A - Self-aligning pitman-bearing box - Google Patents

Description

Feb. 1', 1927. 1,615,940 l V. L. FORSYTH SELF ALIGNING FITMAN BEARING BOX Filed Sept. 21, 1925 Patented Feb. 1, 1927.

UNETED STA'S VALORIS L. FORSY'I, OF FORT WORTH, TEXAS.

SELF-ALIGNING PITMAN-BEARING BOX.'

Application led September 21, 1925. Serial No. 57,527.

web type of pitman as compared with a tubular type.

A further object of the inventlon 1s to mount the box on its fulcrum pin so as to be free to shift laterally as well as to rock on said fulcrum pin, thus preventing twisting of the wrist pin and assuring a free and smooth action.

A construction designed to carry out the invention will be hereinafter described to-` gether with other features of the invention.

r1`he invention will be more readilyl understood from a reading of the following specification and by reference to the accompanying drawings, 1n which an example of the invention is shown, and wherein:

Fig. 1 is a side elevation of a pitman hav ing a bearing box therein constructed in accordance with my invention,

Fig. 2 is a side elevation of the same, a port-ion of thevpitman being omitted, i

Fig.4 3 is a vertical sectional view with the stirrup omitted,

lFig. 4 is a cross-sectional view .taken on the line 4 4 of Fig. 1,

Fig. 5 is a cross-sectional view taken on the line 5-5 of Fig. 1,

Fig. 6 is a cross-sectional view taken on the line 6-6 of Fig. 2, and

-Fig. 7 is a sectional view' showing the rib 'in the box opening of the pitman.

In the drawings the numeral 10 designates a. pitman, which as is shown (Fig. 6) is H- shape inA cross-section, but which may be made of any of the web shapes commonly used in structural beams. Near the lower end of the pitman a rectangular opening 11 is provided by cutting out the web. stirrun 12 is suitably attached to the upper end of the web. A bearing` boxcomprising an upper member 13 and a lower member 14 and divided at its transverse center, is mounted in said opening. Each member has a semi-cylindrical seat 15 for receiving a bearing member 16 of suitable metal. The members 16 when assembled provide a cylindrical bore or bearing surface. The details of the foregoing parts may vary according to the conditions of use and manufacture.,

1n order that the box may rock or oscillate the lower member has a reducedboss 17 disposed transversely of the bore of the bearing members 16. 'The boss has a longitudinal concaved recess 18 in its under surface, whereby the boss may fulcrum on a pin19 extending transversely through the pitman and suitably secured therein. Sufficient clearance in the opening 11 around the box is provided so that the box may' rock freely. Au important feature of the invention resides in the flaring sides 18 given to the recess 18. the outer ends and permit the box to shift or oscillate laterally to either side on the pin, as well as to rock in a vertical plane on said pin.'

These sides Hare from the centerto In preparing the vpitrnan 10, vertical ribs i 11 (Figs. 1 and 7) are provided on the side of the opening 11 where the web is cut out. These ribs are rounded off transversely and act to limit shifting of the box longitudinally of the pin 1.9, thus eliminating end play of the box, but permitting free horizontal and vertical movement as described.

A Wrist pin 20 of the usual construction has its collar 21 bearing against the end of the box. For holding the members of the box together a wedge 22 is passed through slots 23 in the pitman parallel to the pin 19. The upper member 13 of the box has a transverse groove 24 provided with a convex bottom cut on a radiushaving its center (fo-iucident with the center of the pin 19. The under edge of the wedge is curved to conform `to the contour of the bottom of the groove. y

The wedge is driven in to hold the box and its bearing members in contact with the wrist pin 2O and a cotter pin 25 is passed through one of a series of holes 26 in the wedge to keep thelatter in place. It will be seen that the box mayl rock on the pin 19 because the bottom of t e groove 24 will ride under the wedge. This oscillation will be ample to compensate for any variation of the pitmanl from its perpendicular position with relation to the wrist pin. The flaring recess 18 will compensate any twisting movement by permitt-mg the box to shift horizontally on the pin 19, thus avoiding breaking of the wrist pin or injuring the pitman. It is obvio'us that the bearing box is adequately supported center of the bore to and a proper bearing is had for the Wrist pin 20. Whenever the pitman is distorted the box will retain its alignment with the wrist pin 20, thus avoiding undue friction, strains and breaks.

Various changes in the size and shape of the different parts, as Welll as alterations and modifications may be made within the scope of the appended claims. 'The pitman need not be tubular or flattened, but may be otherwise constructed to receive the box.

What I claim, is:

l. The combination with a. pitman, of a fulcrum pin mounted therein, a wrist pin bearing box having a concave rocking seat upon its under face for circumferential movement upon said pin and the sides of said seat being ared from its center outwardly to form a bearing point to permit said box to oscillate transversely. to the axis of said pin, and means for holding the box in the pitman against vertical movement relal tive to the fulcrum pin but permittingrocking movement thereon.

2. The combination with a pitman, of a fulcrum pin mounted therein, a wrist pin bearing box having a concave seat .upon its under side for circumferential rockingupon said pin and the sides of said seat being flared in opposite directions to form a central bearing to permit said box to oscillateN transversely to the axis of said pin, and a fastening device in the pitmanA with which the upper portion of the box has rocking-'enf gagement.

3. The combination with a pitman having an opening and vertical ribs on each side' thereof, of a wrist pin bearing box mounted in the opening of the pitman and having its ends terminating at the ribs thereof, a bossy upon the lower portion of the box having a lengthwise bearing at a right angle to the bore of the box and a flared side wall having va bearing at s1 listantially the longitudinal ermit said box to oscillate transversely of its lengthwise bearing, a transverse fulcrum pin .in the pitman engaging the lengthwise and side wall bearings of the boss to permit oscillation upon eiier bearing, and means for retaining the upon said pivot of the box,

bearing box in engagement with said fulcrum pm.

4. The combination with a pitman having an opening, of a wrist pin bearing box mounted in the opening of the pitman, a boss on the lower portion of the box having a lengthwise bearing at right angles to the bore of the box and provided with a transverse pivot intermediate the ends of said bearing, a transverse fulcrum pin in the pitman mounted to oscillate in said bearing or the upper portion of the box having a groove with a convex bottom, and a fastening member mounted` in the pitman and engaging in said groove, the groove having a width greater than the thickness of the fastening device to allow the box to rock.

5. The combination with a pitman, of a wrist pin bearing box having a rocking seat in its under side, a fulcrum pin mounted in the pitman and engaged in the seat of the box, said seat being formed to permit the box to rock circumferentially upon the pin and to oscillate transversely to the axis of the pin by a pivot thereon, means for holding the box in contact wit-h the pin, and means engaging the sides of the box for preventing movement of the box axially of the `pin while permitting the circumferential and transverse movements of the box.

6. The combination with a pitman having an opening and vertical ribs on each side of the opening, of a wrist pin bearing box mounted in the opening of the pitman, having. its ends terminating atrthe ribs of the pitman opening, a boss on the lower portion of the boxl having a flared recess at right angles to the bore of the box, a transverse fulcrum pin in the pitman engaged in the recess of the box, the upper portion of the box having a grooveI with a convex bottom, and a fastening member mounted in the pitman and engaging in said Groove, the groove having a width greater than the thickness of the fastening device to allow the box to In testimony whereof I aix my signature.

VALORIS L. FORSYTH'.

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