Clamp for clamping an object

A clamp comprises opposed members having clamping surfaces defining a distance therebetween for receiving and clamping an object. An adjustment mechanism is associated with at least one of the members for varying the distance over a continuous range. A spacer assembly being removably associated with at least one of the members for varying the distance by at least one discrete increment.

FIELD OF THE INVENTION

This invention relates to a clamp. In particular, though not exclusively, the invention relates to a clamp used as a base for attaching an item to a surface.

BACKGROUND OF THE INVENTION

Clamps are used for numerous reasons. In some instances, a clamp is used to hold a work piece in place to be worked on. In other instances, a clamp is used to provide a base to mount an item to a surface.

In the case of a table clamp, the clamp can be used as a base for mounting an item on the table. For example, the clamp is fastened to the table; the clamp is adapted to connect to an arm; and an item can be suspended from the arm which is connected to the clamp. Examples of items attached to tables in this manner are task lamps, computer monitors, and various trays for holding items such as office supplies and telephones.

A clamp used for such a purpose is typically designed to accommodate tables of varying thicknesses. Such clamps are often C-clamps which include a screw that can be used to adjust the distance between the opposing clamping surfaces of the C-clamp so the clamp may be tightened against the table and thus held in place. The range of thicknesses of tables to which such a C-clamp can attach is limited by the size of the C-clamp and the length of travel of the screw in the C-clamp. To accommodate a greater range of table thicknesses, typically the size of the C-clamp and the length of the screw needs to be increased.

SUMMARY OF THE INVENTION

In a broad aspect, the invention provides a clamp comprising a frame supporting opposed members having clamping surfaces defining a distance therebetween for receiving and clamping an object; an adjustment mechanism associated with at least one of the members for varying the distance over a continuous range; and a spacer assembly being removably fastenable to at least one of the members for varying the distance by at least one discrete increment.

In some embodiments, the opposed members comprise a first member and a second member and the spacer assembly is associated with the first member.

In some embodiments, the spacer assembly comprises a block having a thickness and the block and the first member define co-operating protrusions and receiving portions for fastening the block to the second member with the distance decreased by the thickness.

In some embodiments, the protrusions comprise the first member having parallel arms which define a channel therebetween and the receiving portions comprise a narrow portion of the block sized to receive the arms.

In some embodiments, the narrow portion comprises a post which connects a first portion of the block to a second portion of the block.

In some embodiments, the first portion of the block has a first thickness and the second portion of the block has a second thickness different from the first thickness and the block can be reversibly fastened in the first member wherein the distance can be decreased by either the first thickness or the second thickness.

In some embodiments, the spacer assembly further comprises at least one block adapter having an adapter thickness wherein the block and the block adapter define co-operating adapter protrusions and receiving portions for fastening the block adapter to the block to further decrease the distance by the adapter thickness.

In some embodiments, the adapter protrusions comprise at least one post projecting from the adapter and sized to fit into a hole on the block.

In some embodiments, the clamp further comprises at least one second adapter having a second adapter thickness wherein the adapter and the at least one second adapter define further co-operating protrusions and receiving portions for fastening the second adapter to the block adapter to further decrease the distance by the second adapter thickness.

In some embodiments, the spacer assembly comprises a rod having spacing elements slidably retained on the rod; a space being movable between the spacing elements by moving the spacing elements on the rod; the first member defining a protrusion for insertion into the space for fastening the spacer assembly to the first member, the distance decreasing by the thickness of the spacing elements inserted into the distance.

In some embodiments, the protrusions comprise the first member having parallel arms which define a channel therebetween for receiving a portion on the rod extending through the space.

In some embodiments, the spacing elements comprise a plurality of rings of different thicknesses.

In some embodiments, the spacing elements further comprise plates fastened on each end of the rod.

In some embodiments, the adjustment mechanism is associated with the second member.

In some embodiments, the adjustment mechanism comprises a threaded opening in the second member and a threaded bolt axially moveable therein in a direction of the distance.

In some embodiments, the bolt comprises an orifice opposite the direction, the orifice being sized to receive a post for mounting the post thereto.

In some embodiments, the post is a post of a table lamp for mounting the table lamp to a table.

In some embodiments, the clamp further comprises a removable sleeve encircling a head of the bolt.

In some embodiments, the adjustment mechanism further comprises a plate mounted to swivel on the end of the bolt for clamping the object.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIGS. 1 to 6show a clamp10in three possible configurations. The three possible configurations change the distance between the clamping surfaces. The distance is changed in increments by the presence and orientation of a spacer12. The distance can also be varied by the use of an adjustment mechanism at the opposite end of the clamp. The adjustment mechanism includes a bolt or screw14connected to a clamping plate16. Travel of the screw14into and out of the clamp interior will adjust the position of the clamping plate16over a continuous range of the travel of the screw14and thereby also change the distance between the clamping surfaces.

Turning to the clamp in further detail, the clamp10includes a supporting frame or body18. The body18is made up of two spacer arms20connected to two connecting arms22which in turn are connected to two head arms24. In this embodiment, the arms20,22and24have a square cross-section shape. The head arms24in turn connect to a head26. As can be seen in the drawings, the embodiment ofFIGS. 1,2and3is C-clamp. In other words, the arms20,22and24define a squared C-shaped frame. In this embodiment, the spacer arms20are parallel to and spaced from the head arms24by the length of the connecting arms22, with the connecting arms22being perpendicular to both the spacer arms20and the head arms24. The arms20,22and24consist of two parallel arms spaced by a constant gap.

Other orientations of the arms could be utilized with corresponding changes made, if needed, to the spacer12and the clamping plate16. This invention is also applicable to other styles of clamps which are not C-clamps and could have different configurations for supporting the spacer12and the opposing clamping surface, such as the clamping plate16of this embodiment.

The head26in this embodiment, is connected to the head arms24at the opposite end of the head arms24from the connecting arms22. It would be appreciated, that the head arms24can be completely eliminated if the head26were of a sufficiently large diameter. The head26is internally threaded with complimentary threads to the threads of the screw14so that the screw14can be screwed to move the clamping plate16into and out of the interior of the clamp10to shorten or lengthen a distance X1between the clamping surfaces.

The clamping plate16of this embodiment is generally ring shaped with an extension32which is smaller in diameter than the body of the clamping plate16and is roughly of the same diameter as the screw14. However, such an extension is not essential. The clamping plate16is connected to the screw14by a smaller screw30which extends through a hole in the center of the clamping plate16and screws into the screw14. The clamping plate16also has a depression34in the clamping surface. This depression34may be tapered or another shape depending on the shape of the head of the connecting screw30. This depression ensures that the clamping surface of the clamping plate16contacts the surface to be clamped rather than the head of the connector screw30. Additionally, when the connector screw30is screwed tightly into the clamping plate16, the clamping plate16can still ride freely on the screw30. In other words, the clamping plate16can rotate around on the screw30.

Other means of securing the clamping plate16may also be used. For example, plate16may ride on a pin that is snap fit into the screw14.

It will be appreciated that the clamping plate16and the screw30may be totally eliminated. The clamping surface on this side of the clamp would then be provided by the end of the screw14. The clamp10may have to be held more securely for mounting in this configuration to prevent the contact between the rotating end of the screw14and the surface being clamped from causing the clamp10to travel along the surface. A protective material may also be used to protect the surface being clamped.

The screw14has a screw head15. A screw cap28can be used to cover the screw head15and the upper threads of the screw14. In this embodiment, the screw cap28is generally cylindrical. However, numerous other shapes may be used which are decorative such as triangular, octagonal or patterned screw caps. The screw cap28is a sleeve which covers the head of the screw14and it will be appreciated that the screw cap28may be completely eliminated. In this embodiment, the screw cap is retained by a press fit onto the screw head15. Other retaining means such as a retaining screw through the cap28and the head15could also be used.

As best seen inFIG. 4, there is a hole36which extends through the screw cap28and down into the screw14. This hole36is a blind hole in this embodiment. In other words, it will typically not extend through the end of the screw14. However, it could extend the entire length of screw14. The hole36is for mounting an item on the clamp. For example, a task lamp may have a cylindrical end that is sized to fit within the hole36. The positioning of the hole36is also visible in FIGS.5and6. The hole36need not extend through the screw14, for example, there may be a block of material mounted above or on the back of the arms22and the hole36may extend through that block.

Although the hole36and a complementary post at the bottom of a lamp could be used to mount a lamp on the clamp, any other fastening means known in the art may be used. For example, the clamp10could have a plate with holes on the arm24and an item to be fastened could have complementary holes for screwing to the plate. The advantage of the use of the clamp10in such a configuration is to avoid the necessity of drilling screw holes in, for example, the table.

As previously explained, the distance between the clamping surfaces may be varied by screwing the screw14in the head26inwards to the interior of clamp10and outwards from the interior of the clamp10. In this example, the other way of altering the distance between the clamping surfaces is by use of the spacer12. The geometry of the spacer12is best seen in the front view inFIG. 5. The spacer12is made up of a thin portion38, a thick portion40and a narrow portion42. In this embodiment, the thin portion38and the thick portion40are both cylindrical in shape and are connected by the narrow portion42. The width of the narrow portion42of this embodiment is sized to fit within the width of the distance between the connecting arms22by being substantially the same width. Similarly, the space between the thin portion38and the thick portion40, in other words the height of the narrow portion42, is sized to fit around the thickness of the spacer arms22by being substantially the same width. With this sizing, the spacer12can be press fit onto the spacer arms22as shown inFIGS. 2,3,5and6and thus retained in position. The particular shape of the spacer12is not essential. For example, the narrow portion42may be narrower and still have a press fit which retains the position. Other means of removably fastening the spacer in position may also be used, including a loose positioning that is secured by the clamping of clamp10when used. The spacer12may be any shape of block which, with the body18, define co-operating protrusions and receiving portions for mounting the spacer block to the body18.

As can be seen by comparing the distances X1, X2, and X3inFIGS. 1,2and3, the distance X1and by extension the thickness of an item which can be clamped, is the maximum of the three distances when the spacer is totally removed as inFIG. 1. When the spacer12is press fit into the clamp with the thin portion38inside the clamp as shown inFIG. 2, the clamping distance is decreased to the distance X2by the thickness of the thin portion38. When the spacer12is press fit into the clamp10in the orientation shown inFIG. 3, the distance is reduced to the distance X3by a larger amount namely by the thickness of the thick portion40.

It will be appreciated that the use of the spacer12allows the distance to be decreased in increments based on the thickness of the portion of the spacer12which is added to the interior of clamp10inside of the spacer arms20. The opposed, in other words the oppositely facing parallel clamping surfaces, are provided by the inner face of the clamping plate16and the inner face of the spacing arms20inFIG. 1, the inner face of the thin portion38inFIGS. 2 and 5and the inner face of the thick portion40inFIGS. 3 and 6.

The use of the spacer12in conjunction with the screw14allows the screw14to be of a shorter length than if the spacer assembly was not available. In other words, for the clamp10to clamp to a thin item, the screw14only needs to be of sufficient length to travel the distance X3depicted inFIG. 3rather than the longer distance X1depicted inFIG. 1. In some embodiments the travel of the screw14is ⅜ inches.

Other embodiments of the invention will now be discussed. The further embodiments will be discussed only to the extent that they differ from the embodiments ofFIGS. 1 to 6. Like reference characters will be used for the same parts and the same parts will not be described in detail.

FIG. 7andFIGS. 8A to 8Dshow a different spacer assembly which can be used with the clamp body18described with respect toFIGS. 1 to 6. A spacer44has the same basic configuration as the spacer12. In particular, the spacer44has a thin portion46connected to a thick portion48by a narrow portion50. As with spacer12, the spacer44is sized to be press fit onto the spacer arms20of the body18of the clamp10. The spacer44differs from the spacer12in that the spacer44has a hole52defined on the outer flat side of the thin portion46and a hole54defined on the outer flat side of the thick portion48as seen inFIG. 8B. The hole52may be square but it also may be other shapes and may not be exactly centered on the surface.

The spacer assembly ofFIGS. 7 and 8Ato8D also includes a thin spacer adapter56and a thick spacer adapter58. The thin spacer adapter56has a protrusion62which is sized to fit within either the hole52or the hole54. Similarly, the thick spacer adapter58has a protrusion60. The adapters56and58also have holes61and63sized to fit the protrusions60and62. It will be appreciated the spacer adapters56and58can be press fit onto the spacer44by inserting the protrusion60or62into the hole52or54. The adapters can therefore be used to vary the thickness of the portion of the spacer assembly which is internal to the clamp10and therefore vary the distance between the clamping surfaces by increments other than the thickness of the thin portion46or the thick portion48. Each of the adapters56and58may in turn have holes61and60on the opposite face from the protrusion so that further adapters may be connected to the adapters to allow further spacing increments. It will be appreciated that other co-operation protrusions and receiving portions for connecting the adapters to the spacer may be used. For example, the adapters may be screwed into position or have edge connectors for snapping into position. It will also be appreciated that the adapters need not be circular or of uniform size. Although the upper and lower surfaces of the adapters56and58and the spacers12and44are parallel, and the clamping surfaces are parallel, it will be appreciated that other configurations may be used. For example, if the clamp is to be attached to a pipe, the clamping surfaces may be concave.

FIGS. 9,10,11aand11bdepict another embodiment of the invention. The side view inFIG. 10appears much the same as the embodiment depicted inFIGS. 1 to 8D, however, it will be appreciated from the perspective view inFIG. 9that a clamp63depicted inFIGS. 9 and 10differs from the clamp10depicted inFIGS. 1 to 3. In particular, the clamp body64of the clamp63is made up of a single piece rather than two parallel members. Clamp body64is made up of a head arm66connected to a connecting arm68which in turn is connected to a spacer arm70in the same manner as arms20,22and24. The screw cap28, the head26, the screw14and the clamping plate16of the clamp63are the same as the components inFIGS. 1 to 8.

Because the spacer arm70of the clamp63is a single piece, a spacer72of the clamp63differs from the spacer12of the clamp10. The spacer72is made up of a thin portion74and a thick portion76similar to the thin portion38and the thick portion40described with respect to spacer12. However, the thin portion74and the thick portion76are connected by a different means. Rather than having a narrow portion42which is press fit between two spacer arms20, in this embodiment, there are connecting posts78on the sides of the spacer72. These connecting posts78connect the thin portion74and the thick portion76as shown inFIGS. 11A and 11B. As can be seen fromFIG. 9, the positioning of the connecting posts78allow the spacer arm70to be inserted between these connecting posts to fasten the spacer72in position. In other words, the thickness of the spacer arm70substantially equals length of the connecting posts78and the width between the connecting posts78substantially equals the width of the spacer arm70so that the spacer72is press fit into position around the spacer arm70. A press fit is not essential and other configurations may be used. For example, one connecting post may be eliminated if the remaining connecting post is sufficiently rigid. The connecting posts78may be separate components which are attached to the thin portion74and the thick portion78, for example, by an adhesive. Alternatively, the entire spacer72may be machined from a single block of material.

The spacer72could also be used with the clamp10and fitted to the outside of the spacer arms22. The use of adapters as shown inFIGS. 7 to 8Dcould also be made to the spacer72ofFIGS. 9 to 11B. The arms22and24may also be a single arm like arms64and66.

FIGS. 12 to 15depict another embodiment of the invention. In particular, these Figures depict a clamp80. The basic configuration of the clamp body81is the same as described with respect toFIGS. 1 to 6. In particular the clamp80is made up of a body81comprising spacer arms87connecting arm83and head arms85. In this embodiment, these arms are depicted as having a tubular rather than square shape. The continuous adjustment assembly is comprised of the head26, the screw14and the clamping plate16as previously described. InFIG. 12, the screw cap28is removed so that the screw head15is visible.

This embodiment includes a spacer84. The spacer84is made up of first spacer end86in a second spacer end88. The spacer ends86and88are connected by a rod90. On the rod90between the spacer ends86and88are spacer elements which are thin spacer rings92and thick spacer rings94. The spacer rings92and94each have a hole through them which is larger than the diameter of the rod90. This allows the spacer rings92and94to move freely along the rod92within the limits of travel imposed by the spacer ends86and88.

The entire rod90is not occupied by spacer rings92and94. It will be appreciated that there will always be a blank area or gap on the rod90as shown inFIG. 12. This area can be repositioned along the spacer84by sliding the spacer rings92and94. For example,FIG. 15depicts the gap in one position andFIG. 14depicts the gap in another position. The size of this gap in this embodiment is about the same as the thickness of the spacer arms20so that the spacer arms20can be press fit between any two successive spacer rings92,94or between a spacer end86or88and the next adjoining spacer ring92and94. This allows for a wide range of incremental spacer thicknesses to be added to the interior of the clamp80. For example, inFIG. 14, the distance has been decreased to a distance X4by the cumulative thickness of the spacer end86, three thin spacer rings92and two thick spacer rings94. In contrast, inFIG. 15the distance has been reduced to a distance X5only by the thickness of the spacer end86and the thickness of one thin spacer ring92and one thin spacer ring94.

It will be appreciated that the spacer84may have an effective thickness within the clamp80equal to the thickness of any successive grouping of spacer rings92and the associated spacer end86or88. The spacer ends86and88may be smaller and fit within a recess in the end most spacer rings so they do not add to the effective thickness. Any thickness of rings and ends and positioning the spacer rings may be employed. For example, the rod90may be telescoping so that no gap is left and the rod is expanded to allow the insertion of the spacer arms20into the spacer84. Alternatively, there may be multiple gaps. It would also be appreciated that spacer84may be configured similar to the spacer72ofFIGS. 9 to 11Bwith peripheral rods rather than a central rod.

Although the embodiments depicted show circular spacers, it would be appreciated that other shapes may be employed. The spacers also may be screwed in or slid in from the sides rather than the front. The spacer, rather than the screw can have a hole or other protrusion or receiving portion to which an object can be mounted.

Although the embodiments depicted show the continuous adjustable screw assembly at one end of the clamp and the spacers at the opposite end of the clamp, it will be appreciated that spacers could also be attached to the clamping plate or be used in line in the connecting arms22as extensions.

An adjustable assembly other than a screw may be used as the complementary adjustment assembly to the spacer assembly. For example, a cam assembly may be used. The screw14may be replaced by a shaft connected to a cam. The cam in turn is connected to a rod. When the cam is in a released position, the shaft would slide freely up and down inside the head. When the rod is rotated to the engaged position, the cam will press against the shaft, holding it in place.

The parallel connecting arms22may also be used to facilitate a tracking system. For example, the arms may be extended to a much greater length than depicted in the figures and elements fixed between these parallel tracks or arms.