US 3815434 A
A quick action operating nut assembly for a screw of a screw type jack having a pair of hingedly interconnected complementally threaded nut halves swingable between an open position for receiving, or for removal from, the screw and a closed position for threadedly engaging the screw so that the nut assembly can be selectively applied to the screw at any desired position along its length. One of the nut halves has a radially extending arm and the other has a radially extending lug. A sleeve is slidably mounted on the arm moveable into and out of locking engagement with the lug when the nut halves are in a closed position.
Description (OCR text may contain errors)
United States Patent 11 1 [111 3,815,434 Seger June 11, 1974  QUICK ACTION NUT ASSEMBLY FOR 1,065,801 6/1913 Hammers 74/424.8 A SCREW TYPE CK 2,654,567 10/1953 James 74/4248 A X  Inventor: lcjauijgggggt Seger, Vancouver, B. Primary Examiner Leonard H Germ Attorney, Agent, or Firm-Carver and Company  Assignee: George Wilburt Jackson, West ggrrlisgsver, British Columbia, ABSTRACT A quick action operating nut assembly for a screw of  Flled' July 1972 a screw type jack having a pair of hingedly intercon-  App], No.: 275,187 nected complementally threaded nut halves swingable between an open position for receiving, or for removal  U S Cl 74/424 8 A from, the screw and a closed position for threadedly  In} .Cl F161] i/ls g g g the Screw so that the nut assembly can be lectively applied to the Screw at any desired position  Field of Search 74/424.8 A, 459 along its length one of the nut halves has a radially  References Cited extending arm and the other has a radially extending lug. A sleeve is slidably mounted on the arm moveable UNITED STATES PATENTS into and out of locking engagement with the lug when 15,1 12 5419;] Masodn 74/424.8 A the nut halves are in a closed position, 463,301 ll 18 l Bran ner 950,431 2/1910 Bradford 74/424.8 A 3 Claims, 3 Drawing Figures QUICK ACTION NUT ASSEMBLY FOR SCREW TYPE J ACKS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to operating nut and screw assemblies for screw type jacks.
2. Prior Art Screw type jacks, conventionally, are extended or retracted by manipulation of an operating nut threaded on a jack screw, the nut bearing on the top of a tubular leg, out of which the screw extends. Jacks of this type are extensively used as adjustable supports for slab work in concrete construction and are often interconnected in gangs, each gang of jacks being moveable as a unit.
The screws of each jack of each gang are usually in a retracted position when setting a gang in a position to support the concrete form work. Each of the operating nuts is then manipulated in turn to obtain the required extension of the screws. After the concrete has set the screws must then be retracted by again manipulating the operating nuts in order to obtain necessary clearance for the gang of jacks to be removed as a unit from beneath the newly poured concrete. Retraction of one foot or more is often necessary to clear beams, etc.
Manipulation of the nuts is a hand job and, as the screws are usually reasonably fine threaded, extension and retraction of the screws is a labourious, time consuming operation.
In order to reduce time required in extension and retraction of screws removable shims which can be positioned between the jack operating nuts and the jack legs have been used, however useof shims is not entirely satisfactory as shims, being separable components, are easily lost. Furthermore shims are often quite difficult to apply and are prone to accidental dislodgement when manipulating a nut. It is also usually necessary, to have variable shieves of different sizes and lengths.
SUMMARY OF THE INVENTION The present invention provides an operating nut assembly for a screw jack which can be applied to or removed from a jack screw so that the nut assembly can be selectively positioned longitudinally of the screw to reduce amount of nut manipulation normally required to effect extension or retraction of the screw.
The operating nut assembly of the present invention includes a pair of hingedly interconnected complementally threaded nut halves which can be swung between open and closed positions so as to effect engagement with or disengagement from the screw, an arm extending radially from one of the nut halves, a lug extending radially from the other nut half, and a locking member slidably mounted on the arm for movement into and out of locking engagement with the lug when the nut halves are in a closed position.
A detailed description following related to the drawings gives exemplification of preferred embodiment of the invention which, however, is capable of expression in a structure other than that particularly described and illustrated.
DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation of a nut assembly of the invention shown in operating position on a screw jack,
FIG. 2 is a perspective of an operating nut assembly of the invention in an open position, portions being removed for clarity of illustration,
FIG. 3 is an enclarged central sectional view of a portion of the operating nut assembly shown in locked and unlocked positions.
DETAILED DESCRIPTION FIG. I
An operating nut assembly, generally 2, of the invention is shown in operating position on a screw 3 which extends from a tubular leg 4 of a screw jack 5. The jack leg conventionally has a base plate 6 and a saddle 7 is usually secured to the upper end of thescrew for supporting beams and the like. The nut assembly which rotatably bears on the upper end of the jack leg can be rotated to effect extension or retraction of the screw relative to the leg. The jack 5 is often connected in a gang with other similar jacks, not shown, by braces or other known means.
FIGS. 2 and 3 The nut assembly 2 has a pair of complementary nut halves l I and 12 having adjacent ends 13 and 14 which are hingedly interconnected for swinging movement on a hinge pin 15. The nut halves are swingable between an open position, as shown in FIG. 2, and a closed position as shown in FIG. 3, and are internally threaded, the threads of each nut half complementing each other when the halves are in the closed positions. The threads terminate short of the bearing surfaces 16 and 17 of the nut halves so as to protect ends of the threads from damage.
The nut half 11 has a radially extending cylindrical arm 18 diametrically opposite the hinged end 13. The arm has a longitudinal slot 19 for receiving, when the nut halves are in the closed position, a lug 21 which extends radially from the nut half 12. The slot 19 terminates short of an outer end 23 of the arm in an end wall 24, the end wall constituting an abuttment surface which is spaced from an outer end 25 of the lug when the nut halves are in a closed position.
A cylindrical sleeve 26, which acts as a locking mem- 7 her and having an inner end 27 and an outer end 28, has a slidable fit on the arm 18. The sleeve, adjacent the inner end 27, is indented to provide an inner projection 29 which acts as a detent engageable with the end wall 24 to limit outward movement of the sleeve on the arm.
As seen in FIG. 3 the sleeve is moveable between a release position, shown in solid outline, in which the inner end 27 clears the outer end of the lug, and a locking position, shown in broken outline, in which the lug is received within the inner end of the sleeve.
A tension spring 31 in the sleeve is connected at one end to the outer end of the arm and at an opposite end to an inwardly extending lip 32 adjacent an outer end of the sleeve and normally urges the sleeve to the locking position.
To apply the nut assembly 2 to the jack screw 3 the sleeve is moved to its release position, FIG. 3, and the nut halves swung to an open position for receiving the screw. The nut halves are then swung together so that they threadedly engage the screw and the sleeve 26 is then released so that it automatically moves to its locking position under the influence of the spring 31. The nut assembly can then be manipulated as a conventional nut to extend or retract the screw.
in order to remove the nut assembly from the screw the sleeve is pulled against the action of the spring 31 to its release position. Pressure against the nut halves automatically swing them to their open position so that the nut assembly can be removed from the screw to allow the screw to retract into the jack leg.
1 claim: 1. An operating nut assembly for attachment to a screw of a screw type jack, the assembly comprising:
a. a pair of hinged, complementary threaded nut halves adapted to be swung between an open and a closed position so as to enable the nut assembly to be fitted to or removed from the screw, b. an arm extending radially from one of the nut halves, c. a lug projecting radially from the other nut half and extending parallel to the arm when the nut halves are in a closed position,
2. An operating nut assembly as claimed in claim 1 in which the arm has a slot for receiving of the lug when the nut halves are moved to the closed position.
3. An operating nut assembly as claimed in claim 1 in which the threads of the nut halves terminate short of the side surfaces of the latter,