Implements or apparatus for applying pushing or pulling force – Floor jack type – Screw
Reexamination Certificate
2000-02-25
2001-09-18
Watson, Robert C. (Department: 3723)
Implements or apparatus for applying pushing or pulling force
Floor jack type
Screw
Reexamination Certificate
active
06290209
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to pushing tools, and more particularly to a tool which automatically clamps itself to one environmental object while simultaneously exerts a pushing force on a second environmental object. An illustrative application is in the field of carpentry. The tool anchors itself to, for example, a joist, while exerting a pushing force on a board which is to be nailed to that joist. Fields other than carpentry can benefit from the invention. Wherever there is an object requiring force to move beyond that which a person can reasonably exert, and that object is in close proximity to a fixed point of anchorage, the present invention can profitably be brought to bear on the object being moved.
2. Description of the Prior Art
Professional carpenters, home owners, hobbyists, and others engaging in carpentry from time to time encounter situations wherein rough and semi-finished lumber pieces such as planks and boards are warped to the point that they are barely if at all acceptable for being installed in a construction project. It is usually desired that buildings and other projects have straight, flat surfaces and perpendicular angles between boards. Warped boards and planks degrade suitability of the completed project. However, economics dictate that commercial supplies of rough and semi-finished lumber usually include warped pieces. The craftsman must deal with less than ideal lumber as best he or she can.
Lumber for constructing buildings and related structures such as exterior decks, porches, garages, and the like must be sufficiently strong to bear considerable weight. Therefore, lumber is too strong for a carpenter or other craftsman to bend into an acceptable configuration by hand. A manual tool to perform such bending is desirable when poor quality lumber is to be incorporated into a structure. The prior art has proposed jacks and similar devices for exerting pushing forces considerably greater than those which can be developed by human strength.
An example is seen in U.S. Pat. No. 5,087,019, issued to Dennis J. Peabody et al. on Feb. 11, 1992. Peabody et al. illustrates a spreader which can expand to exert a pushing force, but in which the device is arranged and acts linearly. That is, the point of anchorage is located colinearly with the axis of the device. This requires that the object receiving the pushing force be moved away from the point of anchorage. In the field of carpentry, it is frequently the case that a board being nailed into the structure being built is not suitably located for a linearly spreader to be effective. In contrast to linear spreaders, the present invention has an automatic clamp which grips a board as it expands to exert force on the board receiving force. The clamp is able to grasp a board not colinearly located with respect to the direction of expansion.
U.S. Pat. No. 5,501,754, issued to Hiroaki Hiraguri on Mar. 26, 1996, shows a device for lifting floor panels. The device of Hiraguri is essentially a linear spreader having structure for engaging floor panels. The engaging structure is located at the point receiving the pushing force. By contrast, the present invention incorporates a clamp which can grasp a supporting object located out of line with the direction of expansion.
U.S. Pat. No. 5,875,606, issued to Lars Dean Jensen on Mar. 2, 1999, describes a wall jack which expands between two opposing wall surfaces when a central screw member is turned. This device lacks a clamp found in the present invention, and cannot grasp one structural member from two sides, as can the device of the present invention.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
SUMMARY OF THE INVENTION
The present invention provides a device which grasps one structural member of a building, and exerts a pushing force on another member of the building. The novel device includes a clamp for clamping and has a threaded rod anchored to the clamp for exerting the pushing force. The axis of rotation of the threaded rod is located relative to the clamp such that the clamp grasps a joist while enabling the rod to press against a cross member laid over the joist. The threaded rod first tightens the clamp onto the joist, then exerts pushing force against the cross member.
The invention is typically employed to straighten flooring and decking lumber such as planks and boards being nailed to joists. The flooring or decking lumber is oriented such that it is perpendicular to and above the joist. This requires a device which can anchor to the joist while exerting a pushing force parallel to but above the joist. The self-clamping pusher of the present invention includes a base block having a threaded bore through which is passed an elongated threaded rod. Clamp jaws are connected to the base block by arms acting in scissors fashion. The clamp jaws close over the joist responsive to rotation of the threaded rod as the base block rides along the threaded rod. When the clamp jaws bear against the joist such that no further closing motion is possible, the base block can no longer ride along the rod. The clamp is secured to the joist and prevented from sliding ineffectually along the joist by cleats formed in the jaws which cleats penetrate the surfaces of the joist.
Instead, continued turning of the rod urges the rod to move helically through the base block. Alternatively stated, at first, the threaded rod does not move axially after its forward end contacts the board or plank. Instead, the base block moves relative to the joist and board or plank until the clamp has fully squeezed the joist. After this, the clamp prevents the base block from moving, and the rod is forced to move relative to the board or plank. The forward end of the rod thus advances, imposing pushing force against the board or plank. Thread pitch characteristics give the rod leverage such that force developed by the device will force most boards and planks to yield to this force, and thereby straighten. In summary, the threaded rod both operates the clamp and also subsequently brings force to bear against a board or plank being straightened.
Accordingly, it is a principal object of the invention to provide a device capable of anchoring to a joist and also exerting a pushing force on lumber located above the joist.
It is another object of the invention that the device operate by rotating a single member.
It is a further object of the invention that clamping and pushing be performed sequentially such that rotation of one member first engage the joist and subsequently apply pressure to the lumber located above the joist.
Still another object of the invention is to assure secure grip of the joist.
It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. dr
BRIEF DESCRIPTION OF THE DRAWINGS
Various other objects, features, and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein:
FIG. 1
is an exaggerated, environmental top plan view of an embodiment of the invention shown in an initial position engaging a workpiece.
FIG. 2
is an environmental top plan view similar to
FIG. 1
, but showing adjustment of the novel apparatus to apply force against the workpiece.
FIG. 3
is a diagrammatic detail view of the embodiment of
FIG. 1
showing range of motion of components shown at the center of
FIG. 1
, but which components are somewhat obscured in the view of FIG.
1
.
FIG. 4
is an environmental, end elevational view of the emb
Siemens Patent Services
Watson Robert C.
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