In scissor type clamp

An improved scissor-type clamp includes two opposing clam shell type members, one male and one female, that pivot together, are biased outwardly by coil springs and are held together by a thumbscrew. Embodiments feature rectangular and tapered opposed clam shell portions and one embodiment includes identical clam shell members.

This invention relates to a clamp with opposed ball receiving ends for clamping a movable object in changeable fixed relation to a fixed base and, more particularly, to a scissor type clamp having opposed ball receiving ends.

BACKGROUND OF THE INVENTION

Adjustable mountings for cathode ray tubes (CRT), light emitting diode (LED), and/or plasma screens and other monitors are quite popular as desktop computers have become tower designs built to be positioned out of sight under a worker's desk. The mounting may be fixedly positioned at one end on a desk, on a wood or metal stand positionable on the desk, or on a wall or other structure.

One such clamp presently utilized to adjustably mount a pair of ball mounting ends thereto is found at U.S. Pat. No. 5,845,885 issued to Carnavalli Dec. 8, 1998. The clamp disclosed in Carnavalli has opposed double clam shell type ends held together by both being pivotally mounted to a central bolt having a handle screw threaded onto one end thereof. With each of the centrally facing clamp halves, freely rotatable about the bolt axis and also axially movable depending upon the tightness of the handle on the bolt, the clamp tends to be somewhat unstable until the handle is fully tightened on the bolt clamping each of the clamp halves onto its respective ball mounting.

A need has developed for an improved double ended ball holding clamp having improved stability in its unclamped mode.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention, generally stated, to provide a new and improved double opposed adjustable ball mounting clamp for use, among other mountings, for adjustably positioning a cathode ray tube or light emitting diode screen thereon.

Another object of the present invention is the provision of an improved double opposed ended ball mounting clamp having a scissor clamping feature.

The invention resides in a scissors type clamp with opposed ball receiving heads. The clamp comprises a pair of elongate complementary split arm members with each including hollow semi-ball shape ends facing a common plane. Each split arm member includes a pivotal mounting positioned substantially centrally between each of the semi-ball shape ends. The pivotal mounting on one of the pair of split arm members is complementary to a pivotal mounting on the other of the split arm members. The clamp further includes adjustable fastener means retained on each of the pair of complementary split arm members offset to a common side of the pivotal mounting for selectively adjusting the distance between complementary ends adjacent one another.

The invention further resides in a scissor clamp comprising a pair of substantially identical clamp members. Each such member includes opposed end portions with each such portion having a recess for providing about half an operative clamp with each such recess facing a common plane from opposing sides thereof and a central portion connecting the opposing portions and crossing the common plane. The central portion is offset to one side of the opposed end portions and includes pivot means through the central portion substantially on the common plane for providing operative pivotal mounting together of the pair of substantially identical clamp members.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring toFIG. 1, a first embodiment of a scissor type clamp, generally indicated at20, constructed in accordance with the present invention as shown most clearly inFIG. 1, receives a first ball-type socket mounting21, generally indicated at21at the bottom thereof, which is preferably mounted on a flat surface, such as a desk, wall, etc. (not shown) and a substantially identical second ball type socket mounting, generally shown in dotted line at21A, which is mounted as shown inFIG. 1, on the bottom of a CRT monitor, generally indicated at22. It should be noted that any item can be attached to the ball mounting21A retained by the clamp20of the invention. LCD, plasma and other flat panel displays may commonly be adjustably positioned by the scissors type clamp of the invention.

The clamp20of the invention includes a pair of scissor-like members, generally indicated at23and24. The only other externally viewable part of the scissor clamp of the invention20is a thumb screw25that holds the members together adjacent one end of the scissor clamp20. The scissor clamp of the invention is preferably made of die cast metal, but can be made of molded plastic, ceramic material, or the like as long as the material is of sufficient strength to support an intended load.

Referring toFIGS. 2 and 3, female scissor part23includes opposing end sections27and28with a pair of spaced apart offset web sections29,30connecting the opposed end sections. The central offset walls29and30each include a female trunion receiving mounting31(only one shown inFIG. 2)32shown in dotted line. Each of the opposed ends27and28of the female scissor member23are hollow with open areas facing a common plane running through the trunion receiving mountings31,32.

Adjacent each of the opposed ends27,28of scissor member23are positioned semicircular recesses35,36that form a boundary of the generally curved end walls37,38, respectively. Each of these recesses forms one half of the means for retaining the scissor clamp on the ball type mountings21,21A. A hollow cylindrical annular wall40is mounted in the interior of end section27extends to the interior of the clamp, and is internally threaded to receive the threaded end of thumb screw25. A similar cylindrical post (not shown) is mounted on the inner wall of end section27extends internally similarly to the hollow cylindrical wall40to receive one end of a spiral spring41. Cylindrical wall40not only receives the threaded end25A of thumb screw25, but also receives and retains a spiral spring42around the outside thereof.

A complementary second scissor member, generally indicated at24, also includes a pair of opposing hollow end sections44,45. In this member they are joined together by an offset single central web46in the hollow interior thereof. End section44also includes a generally cylindrical post47which is adapted to receive and retain around the outside thereof one end of the spiral spring41. Outwardly adjacent the post47is a semicircular recess48that is complementary to recess35on end section27of first scissor member23. At the opposite end of second scissor member24, and the distal portion of end section25, is a fourth semicircular recess50that is complementary to recess36on end section28on first scissor member23. Inwardly thereadjacent on the outer wall51of end section24is a circular aperture52. The threaded end25A of thumbscrew25extends through aperture52. The one end of spiral spring42is retained by the inside surface of the backside51around aperture52.

The central offset portion46or web between the end sections44and45of second scissor member24has positioned centrally on the opposite sides thereof, a pair of trunion mountings (only one shown)54which mount respectively in the female trunion receiving portions31,32, of the first scissor member23. To provide a pivot point for the scissor members to interact.

In operation the assembly is put together by rotating one of the opposed ends of second scissor member24ninety degrees and moving one of the ends44or45through the central aperture33defined between the opposed offset halves29,30. After the end is moved therethrough, the second scissor member is again rotated in a reverse direction to that previously to enable the trunion mountings54to slide into the trunion mounting receiving recesses31,32in the central offset portion of the first scissor member23.

With the scissor members pivotally mounted together, the spiral springs41and42may be compressed and mounted on the posts40,47and the thumb screw25may be inserted through the aperture52and threaded onto the interior of hollow post40to close the scissor clamp or allow it to be opened.

Referring toFIG. 3, the first and second scissor members23,24are shown in their assembled positioned with the semicircular recesses50and36for capturing and retaining the ball-type mountings21,21aare shown in more detail.

Referring toFIGS. 4-10, a second embodiment of the preferred invention is shown generally at60. This second embodiment60is constructed similarly to the first embodiment20with the exception that the outer surfaces of the opposed ends are clam shell shaped and the center offset portions form a more narrow waist that that shown in the first embodiment20.

The clam shell type scissor clamp60of the second embodiment includes first scissor member61, and second opposing scissor member, generally indicated at62. As shown most clearly inFIGS. 5 and 6, the outer surface of the first and second scissor member opposed ends are more rounded or semicylindrical in shape than the outer surfaces of the opposed ends of first embodiment20. First scissor member61, similarly to first scissor member23, includes opposed end portions63and64, previously mentioned, that have semicircular wall with each including a semicylindrical shape recess65,66, respectively.

Likewise, the opposed ends of second scissor member62include semispherical recesses71and72. As with the first embodiment20, the semicylindrical outer walls63,64of first scissor member61and the semicylindrical outer walls68,69of scissor member61both are hollow, with a narrowed waist section between the outer walls on each respective member.

With first scissor member61the narrowed waist portion is composed of a pair of opposed spaced apart web members74,75(FIG. 8) which are canted or offset as shown most clearly inFIG. 7such that the inner edge63aof clam shell63and the inner edge64aof clam shell64are parallel and lie on either side of a center line of the offset portion75. Centrally of each of the offset portions is a trunion mounting76,77and an elongate recess78,79that allows a pivot member, to be discussed in more detail below, to be mounted between those trunion mountings76,77, respectively. The opposed offset central webs74,75together with the bases63b,64bprovide a very rigid central framework for the first scissor member61of the second embodiment. Additionally, first scissor member61of the second embodiment includes an aperture73through the semicircular wall64.

Referring toFIGS. 7 and 8, on the left side of the first scissor member61at the center of the outer wall is an aperture82that extends through the wall63to the interior thereof. On the right side of the inner surface of the outer wall64is a post83that extends into the hollow interior of the clam shell shaped outer wall.

Referring toFIGS. 9 and 10, a second scissor member62of the second embodiment is shown and described and includes similarly to the first scissor member, opposed clam shell outer walls68and69having semispherical recesses71and72positioned at the outer portions of each. As in the first scissor member61, the opposed clam shell outer wall68and69are hollow. Within the interior of the first clam shell portion68, a hollow, generally cylindrical wall84includes a threaded aperture85through the top thereof in which a second thumb screw86may be threadedly received (FIG. 4).

On the hollow inside of clam shell portion69of second scissor member62is positioned a post86similar to post83of the first scissor member and positioned so as to be aligned therewith in spatial relation when the first scissor member and second scissor member are assembled. The threaded aperture85is positioned so as to be aligned with aperture82in the first scissor member in spatial relation thereto when the first and second scissor member61and62are mounted together.

Unlike the first scissor member61, the second scissor member62includes a single offset central web87that is offset in a direction opposite that of the offset web75of the first scissor embodiment such that the opposed edges88and89of clamshell portions68and69are on opposing sides of an axis centrally through the second scissor member62and through the offset portion87. Along this axis is positioned a pair of cylindrical trunions91and92which extend perpendicular to the central axis running parallel to surfaces88and89.

As with the first embodiment, trunions91and92are positioned so as to be fit into trunion mountings76,77, respectively when the first and second scissor member61,62are brought together. As with the first embodiment, the assembly of the scissor members is performed by rotating one clam shell of the second scissor member62ninety degrees and inserting same through the opening between members74,75of the first scissor member61. After the clam shell is positioned therethrough, the member is reverse rotated 90 degrees and the trunions91,92are positioned through trunion mounting recesses78,79into their trunion mounting76,77.

Coil springs93,94(FIG. 4) are positioned around the posts83,86and around the thumbscrew86, respectively to maintain the opposed clam shell halves in an outwardly biased position, absent the threading of thumbscrew86in the threaded aperture85.

In operation, the ball type mountings21,21ashown inFIG. 1may be inserted in the hollow interior of the clam shells so as to extend outwardly through the space between the semispherical recesses65,71and72,66. Thereafter, the thumbscrew86is threaded into its threaded aperture, or tightened therein, until the ball type mountings are secured within the recesses.

The third embodiment100of the scissor clamp includes a pair of identical hollow cylindrical or clam shell shaped scissor member halves101-101, with each having opposing hollow clam shell portions102,103therein separated by a double offset web104. Clam shell portion102includes a semispherical recess105adjacent the end thereof and an aperture106through an outer wall thereof.

Clam shell portion103includes a semicylindrical recess107adjacent the end thereof and a central hollow post108extending from the inner hollow surface thereof that includes a threaded aperture109centrally therein. The double offset central web104includes a central bore111therethrough. When a pair of the scissor members101-101are mounted together, the apertures111-111align so that a pivot pin112and a retaining clip113mounted adjacent the end of pivot pin112retain the two members in a pivotal scissors type mounting.

As in the previous embodiments, a pair of coil springs114-114are mounted between the hollow threaded posts108and the aperture106so as to allow a thumb screw115to be mounted through the aperture within the coil spring and be retained on the threaded interior109of the hollow cylindrical post108. In this embodiment, the inner surface of the clam shell portion102includes a slight ridge around the edge of aperture106on the interior thereof identified as106athat provides a mounting for one end of the coil spring114.

Thus, a simplified version of the scissor clamp utilizing just a pair of a single, preferably molded scissor half members provides a less expensive means of utilizing a scissor clamp for variably mounting an external member, preferably a monitor, CRT, television or the like to an external surface.

While three differing embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the true spirit and scope of the present invention. It is the intent of the appended claims to cover all such changes and modifications which fall within the true spirit and scope of the invention.