DEVICE TO HOLD AND LOCK A SCISSOR JACK SCREW FROM LOOSENING AFTER TIGHTENING

Abstract

A jack screw locking device is provided. The jack screw locking device has a general L-shape defined by a key arm and a lock arm. The lock arm provides a lock slot and the key arm provides a key notch. The former is for operatively associating with a scissor jack's jack screw nut in a locked engagement when the key arm is slid between a fork portion of the scissor jack framing, thereby preventing rotation about torque axis of the jack screw nut. In conditions where the jack screw starts unwinding immediately upon removing the crank, the key notch can be used to engage the same jack screw nut in a holding position prior to the crank being removed, thereby temporarily holding the jack screw in order to effectuate the locked engagement via a second jack screw locking device.

Claims

1. A jack screw locking device, comprising: a lock arm providing a generally centrally disposed lock slot, wherein the lock slot is defined by a hexagonal opening; a key arm orthogonally joined to the lock arm; and a key slot provided at a distal end of the key arm, wherein the key slot is defined by a semi-hexagon notch.

2. The jack screw locking device of claim 1, wherein the lock slot and key slot are dimensioned and adapted to operatively associate with a jack screw nut of a scissor jack.

3. A method of positioning a scissor jack in a locked engagement, comprising: providing a jack screw locking device of claim 1; providing a scissor jack having a jack screw with a jack screw nut, wherein a frame of the scissor jack has a forked portion that operatively associates with the jack screw; sliding the key arm between the forked portion; and operatively associating the lock slot with the jack screw nut.

4. The method of claim 3, wherein the jack screw unloosens prior to establishing a locked engagement with said jack screw locking device, comprising: providing a second jack screw locking device of claim 1; and prior to sliding the key arm of said jack screw locking device, operatively engaging the jack screw nut and the key slot of the second jack screw locking device in a holding position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 is a perspective view of an exemplary embodiment of the present invention;

[0011] FIG. 2 is a perspective view of an exemplary embodiment of the present invention, illustrating installation;

[0012] FIG. 3 is a perspective view of an exemplary embodiment of the present invention, illustrating a locked engagement;

[0013] FIG. 4 is a section view of an exemplary embodiment of the present invention, taken of FIG. 3, with a jack element simplified for clarity;

[0014] FIG. 5 is a perspective view of an exemplary embodiment of the present invention, showing a key arm 18 being installed with a crank 26;

[0015] FIG. 6 is a perspective view of an exemplary embodiment of the present invention, showing a key 18 in a holding position;

[0016] FIG. 7 is a perspective view of an exemplary embodiment of the present invention, showing the crank 26 removed and a key arm 22 holding the jack screw 22 tight in the holding position, while a lock slot 14 of another jack screw locking device 10 is installed in the locked engagement; and

[0017] FIG. 8 is a perspective view of an exemplary embodiment of the present invention, illustrating the removal of the holding position once the lock slot 14 is installed.

DETAILED DESCRIPTION OF THE INVENTION

[0018] The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.

[0019] Broadly, an embodiment of the present invention provides a jack screw locking device. The jack screw locking device has a general L-shape defined by a key arm and a lock arm. The lock arm provides a lock slot and the key arm provides a key notch. The former is for operatively associating with the jack screw nut in a locked engagement when the key arm is slid between a fork portion of the scissor jack framing, thereby preventing rotation about torque axis of the jack screw nut. The key notch can be used to engage the same jack screw nut prior to the crank being removed, thereby temporarily holding the jack screw in order to effectuate the locked engagement via a second jack screw locking device in conditions where the jack screw starts unwinding immediately upon removing the crank.

[0020] Referring to FIGS. 1 through 8, the present invention may include a jack screw locking device 10 for holding and locking a scissor jack screw 22 from loosening after tightening.

[0021] The jack screw locking device 10 may have a lock arm 12 and a key arm 16 oriented orthogonal relative to each other so as to define a general L-shape. The lock arm 12 provides a generally centrally disposed lock slot 14 defining a hexagonal opening. The distal end of the key arm 16 provides a key slot 18 defined by four of the six sides of a hexagon cutout, or in other words a semi-hexagon cutout or notch.

[0022] A method of using the present invention may include the following. One or more jack screw locking devices 10 disclosed above may be provided. A user may crank the subject scissor jack 20 to the desired height and remove the crank wrench and observe if the crank nut 24 begins to unwind immediately. If not, then while holding one jack screw locking devices 10 horizontally so the lock arm 12 is closest and pointing down, the user can insert the key arm 16 into the jack frame just above the crank nut until the lock slot 14 slips over the crank nut 14. The scissor jack 20 is now locked in a locked engagement.

[0023] If immediate unwinding of the jack screw 22 occurs when the crank 26 is removed, but before the above-described locked engagement can be applied, the jack screw locking device 10 may be utilized as illustrated in FIGS. 5-7, and as follows: 1) the key slot 18 of a first jack screw locking device 10 is inserted behind the crank 26 to operatively associate with the jack screw nut 24 to hold the nut 24 from unwinding while the crank 26 is removed; and 2) a second jack screw locking devices 10 is then installed over the crank nut and into the scissor jack frame in the locked engagement described above. The first jack screw locking devices 10 that was used to hold the jack screw nut is removed and used elsewhere.

[0024] Note, the jack screw locking device 10 may be offered as a set of four identical devices, i.e., one for each corner scissor jack of an RV, whereas typically, only the rear two exhibit the tendency to loosen or unwind since the front two are augmented by a tongue jack, which is not subject to loosening.

[0025] The jack screw locking devices 10 may be made of metal or other form-able material. One could cut a blank rectangle in the specified dimensions from a sheet or extruded bar of the specified thickness, then punch or cut a hexagon hole of the specified dimension at one end of the blank at the specified location, then punch or cut an opening with parallel sides of the specified dimension at the other end of the blank at the specified location. The flat blank is then bent to 90 degrees in the specified location. The bracket is then de-burred. To make the present invention of plastic or other moldable material, an injection mold would be required to cast the device in one piece, including the hex hole, opening, and bend. The chosen material would have to be of sufficient strength so as to not tear or deform when used in the specified manner.

[0026] It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.