Work bench including a vise

A work bench includes a frame, a bench surface on the frame with the bench surface including at least two members, one of which is movable along the frame for clamping a workpiece between the members. A mechanism for moving the member includes two screws coupled with the members. The two screws are spaced with the member for moving the member upon rotation of the screws. A sprocket is coupled with each of the screws. A transmission belt or chain is coupled with the sprockets. At least one handle is coupled with one of the screws to rotate the screws. At least one clutch is coupled with the at least one screw to limit clamping pressure on the workpiece. The clutch enables rotation of one screw with respect to the other screw so that workpieces may be clamped between the members and clamping of the workpiece may be accomplished by rotation of the screws with one hand of the operator. Also, a guard may be present which covers the transmission belt or chain. The handle may include a hub, a straight portion, and curved portion extending from the straight portion. A knob extends from the curved portion.

FIELD OF THE INVENTION
 The invention relates to portable work benches or tables which include an
 integral clamping table or vise. More particularly, the present invention
 relates to a work table with a clamping table or vise where the vise may
 be operated with one hand.
 BACKGROUND OF THE INVENTION
 Carpenters, woodworkers and handymen which work with wood as well as other
 materials, often need a work bench or table which may be utilized to hold
 workpieces. Ordinarily, these work benches include a vise which clamps
 portions of the table top together to secure the workpiece on the table.
 One such device is that of the assignee of the present invention which is
 sold under the WORKMATE.TM. trademark. These tables are versatile, provide
 for secure clamping, are compact and are convertible to dual height
 positions.
 The work bench ordinarily includes two vise screws with handles on each
 one. The vise screws, via the handles, are operated by the user with the
 user using both hands. While a user may utilize one hand, the user must
 rotate both handles in order to clamp a workpiece between the clamping
 table members. Accordingly, it is desirable to utilize one hand to crank
 both of the vise screws so that clamping of the workpiece may be
 accomplished by the user using only one hand. By enabling cranking of the
 vise to clamp the workpiece with one hand, the user is capable of holding
 the workpiece in place with his other hand. Also, it is desirable that the
 vise clamp irregular objects while turning the vise screws with one hand.
 SUMMARY OF THE INVENTION
 Accordingly, it is an object of the present invention to provide an
 improved vise for a work bench which enables the vise to be tightened down
 utilizing one hand.
 In accordance with one aspect of the invention, a work bench comprises a
 frame; a table surface on the frame, with the table surface including at
 least two members; one of which is movably coupled with the frame to
 enable clamping of a workpiece between the two table surface members. A
 drive mechanism moves the table members with respect to one another. The
 drive mechanism includes two screws coupled with one of the members. The
 two screws are spaced from one another to move the table member upon
 rotation of the screws. A sprocket is coupled with each screw. A
 transmission belt or chain is coupled with the sprocket to drive the
 screws together. At least one handle is coupled with one of the screws to
 rotate the screws. At least one clutch is coupled with at least one screw
 to limit clamping pressures on the workpiece. The clutch enables rotation
 of one screw with respect to the other screw so that irregular workpieces
 may be clamped between the table members and clamping of the workpiece may
 be accomplished by rotation of the handle by one hand of the operator. The
 clutch is self-actuating. The clutch includes a spring and a detent
 removably coupled within slots in a hub of the sprocket. Also, both screws
 may include a clutch. Further, each screw may include a handle. One of the
 handles has a different configuration than the other to identify to the
 user that clamping of the table surfaces may be accomplished by rotation
 of only one handle to drive both screws.
 In accordance with a second embodiment, a work bench includes a frame; a
 table surface on the frame, with the table surface including at least two
 members; one of which is movably coupled with the frame to enable clamping
 of a workpiece between the two table surface members. A drive mechanism
 moves the table members with respect to one another. The drive mechanism
 includes two screws coupled with one of the members. The two screws are
 spaced from one another to move the table member upon rotation of the
 screws. A sprocket is coupled with each screw. A transmission belt or
 chain is coupled with the sprocket to drive the screws together. At least
 one handle is coupled with one of the screws to rotate the screws. At
 least one clutch is coupled with at least one screw to limit clamping
 pressures on the workpiece. The clutch enables rotation of one screw with
 respect to the other screw so that irregular workpieces may be clamped
 between the table members and clamping of the workpiece may be
 accomplished by rotation of the handle by one hand of the operator. A
 guard covers the transmission belt or chain. The guard is coupled with the
 frame. The guard includes at least one tensioning member unitarily formed
 with and extending from the guard. The guard includes at least one
 alignment member to maintain alignment of the belt or chain to the
 sprocket. A biasing member is associated with the belt or chain to
 automatically adjust to changes in the belt or chain length to take up
 slack and provide positive belt or chain tension. The biasing member may
 be a helical spring. Further, the guard may include two tensioning members
 as well as two pairs of alignment members, each pair sandwiching a tension
 member.
 In accordance with a third aspect of the invention, a work bench comprises
 a frame; a table surface on the frame, with the table surface including at
 least two members; one of which is movably coupled with the frame to
 enable clamping of a workpiece between the two table surface members. A
 drive mechanism moves the table members with respect to one another. The
 drive mechanism includes two screws coupled with one of the members. The
 two screws are spaced from one another to move the table member upon
 rotation of the screws. A sprocket is coupled with each screw. A
 transmission belt or chain is coupled with the sprocket to drive the
 screws together. At least one handle is coupled with one of the screws to
 rotate the screws. At least one clutch is coupled with at least one screw
 to limit clamping pressures on the workpiece. The clutch enables rotation
 of one screw with respect to the other screw so that irregular workpieces
 may be clamped between the table members and clamping of the workpiece may
 be accomplished by rotation of the handle by one hand of the operator. The
 handle includes a hub, a straight portion extending from the hub, a curved
 portion extending from the straight portion, and a knob extending from the
 curved portion. The knob enables rotation of the handle. The curved
 portion has a truncated U-shape with one end coupled with the straight
 portion and the knob extending from the other end. The hub has a desired
 height as well does the straight portion which is less than that of the
 hub. The curved portion has a height greater than the hub. An end of the
 curved portion and a side of the straight portion are continuous forming a
 planar side portion of the handle. A connecting member extends from the
 hub and is unitary with the straight portion and a portion of the curved
 portion. The handle may be injected molded from a plastic material.
 In accordance with a fourth aspect of the invention, a guard for a work
 bench drive transmission comprises a first wall, at least one second wall
 extending substantially perpendicular to the first wall, and at least one
 guide extending from the first wall. The guide extends transverse to the
 direction of travel of the transmission belt or chain. Preferably, a
 second guide extends from the first wall. Preferably, two parallel spaced
 second walls extend from the first wall. An alignment member extends from
 the first wall. Preferably, the alignment member is stamped into the first
 wall and two alignment members sandwich each guide member. Also, a second
 wall includes a biasing member to provide positive belt or chain tension.
 The first or second walls include cut-outs to secure the helical spring
 biasing member to the guard.
 In accordance with a fifth aspect of the invention, a handle for operating
 a movable work bench comprises a hub, a straight portion extending from
 the hub, and a curved portion extending from the straight portion. A knob
 extends from the curved portion to enable rotation of the handle. The
 curved portion has a truncated U-shape with one end coupled with the
 straight portion and the knob extending from the other end. The hub has a
 desired height, as well does the straight portion, which is less than the
 height of the hub. Also, the curved portion has a height greater than the
 hub. Also, one end of the curved portion and a side of the straight
 portion are continuous forming a planar side portion of the handle. A
 connecting member extends between the hub, straight and curved portions,
 and is unitary with the three. The handle is ordinarily molded from a
 plastic material.
 In accordance with a sixth aspect of the invention, a belt or chain drive
 transmission for a work bench comprises two screws adapted for coupling
 with a member to be moved against another member to provide clamping. A
 sprocket is coupled with each of the screws. A transmission belt or chain
 is coupled with the sprockets. At least one handle is coupled with one of
 the screws to rotate the screws. At least one clutch is coupled with at
 least one screw to limit clamping pressures on a workpiece. The clutch
 enables rotation of both screws, one with respect to the other which is
 being directly rotated. The clutch is self-actuating and includes a spring
 and a detent coupled with a slot in a hub of the sprocket. Preferably,
 each screw includes a clutch and each screw includes a handle. Also, one
 of the handles has a different configuration which identifies to the user
 that only one handle may be rotated to drive both the screws. Also, each
 screw includes a stop to position the spring with respect to the sprocket.
 With respect to a seventh aspect of the invention, a work bench includes a
 frame; a table surface on the frame, with the table surface including at
 least two members; one of which is movably coupled with the frame to
 enable clamping of a workpiece between the two table surface members. A
 drive mechanism moves the table members with respect to one another. The
 drive mechanism includes two screws coupled with one of the members. The
 two screws are spaced from one another to move the table member upon
 rotation of the screws. A sprocket is coupled with each screw. A
 transmission belt or chain is coupled with the sprocket to drive the
 screws together. At least one handle is coupled with one of the screws to
 rotate the screws. At least one clutch is coupled with at least one screw
 to limit clamping pressures on the workpiece. The clutch enables rotation
 of one screw with respect to the other screw so that irregular workpieces
 may be clamped between the table members and clamping of the workpiece may
 be accomplished by rotation of the handle by one hand of the operator. A
 guard covers the transmission belt or chain. The guard is coupled with the
 frame. The guard includes at least one tensioning member unitarily formed
 with and extending from the guard. The guard includes at least one
 alignment member to maintain alignment of the belt or chain to the
 sprocket. A biasing member is associated with the belt or chain to
 automatically adjust to changes in the belt or chain length to take up
 slack and provide positive belt or chain tension. The biasing member may
 be a helical spring. Further, the guard may include two tensioning members
 as well as two pairs of alignment members, each pair sandwiching a tension
 member. The handle includes a hub, a straight portion extending from the
 hub, a curved portion extending from the straight portion, and a knob
 extending from the curved portion. The knob enables rotation of the
 handle. The curved portion has a truncated U-shape with one end coupled
 with the straight portion and the knob extending from the other end. The
 hub has a desired height as does the straight portion, which is less than
 that of the hub. The curved portion has a height greater than the hub. An
 end of the curved portion and a side of the straight portion are
 continuous to form a planar side portion of the handle. A connecting
 member extends from the hub and is unitary with the straight portion and a
 portion of the curved portion. The handle may be injected molded from a
 plastic material.
 Additional objects and advantages of the invention will be apparent from
 the detailed description of the preferred embodiment, and the appended
 claims and accompanying drawings, or may be learned by practice of the
 invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
 The preferred embodiment of the present invention is a work bench which is
 identified with the reference numeral 10. The work bench includes a frame
 structure 12 which includes a base 14, four foldable legs 16, two upright
 H supports 18 which extend from the base 16, and brackets 20 at the other
 end of the supports 18. The work bench 22 is generally formed from two
 members 24 and 26 which are coupled with the brackets 20.
 The brackets 20 are hollow and include elongated slots 21 which enable
 movement of the front table 24 with respect to the brackets 20. Also, the
 brackets include apertures 23 to enable the second table portion 26 to be
 stationarily locked onto the brackets 20. An additional slot 25 is formed
 in the side of the brackets 20 to enable the belt 56 to pass into the
 brackets 20 and be coupled with the sprockets 50.
 Two screws 30 are positioned within the brackets 20. The screws include a
 threaded portion 32 which includes a threaded pivot nut 34 which in turn,
 via a block 36, is coupled with the front moving member 24 of the work
 bench 22. Also, the screws 30 includes a smooth shank portion 38 which
 includes a portion which extends out beyond the bracket 20 as seen in FIG.
 1. The smooth shank portion 38 includes a stop 40 as well as apertures 44
 and 46.
 Sprockets 50 are slidably positioned onto the smooth shank portion 38 of
 the screws 30. The sprocket 50, as shown, has projecting members 52 which
 extend into apertures 54 of the belt 56. However, if a chain is used, the
 projections may be substituted for recesses or the like. The sprocket 50
 includes a hub 58 which includes slots or detents 60. The slots 60 are
 adapted to couple with a detent pin 62 which passes through aperture 44 of
 the screw 30.
 A helical spring 64 is positioned on the smooth shank portion 38 abutting
 the stop 40 and the sprocket 50. The spring 64 along with the detent pin
 62, sprocket 50 and sprocket slots 60 act as a clutch which limits the
 pressure which can be applied onto the workpiece. The slot or detent 60 in
 the sprocket enables transmission of light torques necessary to overcome
 friction to move the first member 24 providing one hand operation. At high
 clamping torques, the pin 62 disengages from the sprocket detent or slot
 60 and compresses the clutch spring 64. When unclamping the workpiece, the
 clutch automatically engages the pin 62 via the sprocket detent 60 to once
 again allow one handed operation. The clutch 70 could be incorporated on
 both screws or a single clutch may be provided. In the case of a single
 clutch, the other sprocket will be securely pinned to the vise screw.
 Preferably, each of the screws 30 includes a clutch 70 as described above.
 A guard 80 is positioned over the transmission belt or chain 56. The guard
 80 includes a first wall 82 and at least one second wall 84, preferably
 two, which are perpendicular to the first wall 82 forming an overall
 U-shape and define a channel 85. The guard 80 includes two guides 86
 stamped in and cut out of the first wall 82. The guides 86 extend
 substantially perpendicular to the first wall 80 into the channel 85. The
 guides 86 are substantially parallel with the second wall 82 and apply
 tension on the leading 55 side of the belt 56. The guides 86 help to
 tension the belt or chain as it moves during rotation of the screws 30.
 Also, the guides 86 extend from the wall 82 transverse to the direction of
 travel of the belt 56. The guard 80 spans the length of the belt 56 and is
 secured with the brackets 22 which, in turn, provides additional stability
 for the frame 12.
 Two embossed alignment members 90, 92 sandwich the guide 86. The alignment
 members 90, 92 are stamped into the first wall 82 of the guard 80. The
 alignment members 90, 92 help to maintain the belt 56 or chain onto the
 sprockets 50 during the clamping modes.
 A biasing member 96 is secured to the second wall 82 to automatically
 adjust for changes in belt length and to take up slack in the belt 56. The
 biasing member 96 is a helical spring which is secured on cut-outs 98, 99
 in the guard 80. The spring 96 always provides for positive belt 56 or
 chain tension. The spring 96 is positioned under the belt 56 and tensions
 both the leading 55 and trailing 57 sides of the belt 56.
 Each screw includes a handle 100 and 110. The handle 100 includes a hub
 102, a handle arm 104 and a knob 106. The handle 110 includes a hub 112, a
 straight portion 114, a curved portion 116 and a knob 118. The hub 112 has
 a desired height which is larger than the straight portion 114, but less
 than the curved portion 116. The curved portion 116 has an overall
 truncated U-shape. Also, a connecting member 120 extends between the hub
 112, straight portion 114, and curved portion 116. The handle 110 provides
 a visual indication to the user that the work bench clamping system may be
 rotated with one hand. Also, the hub 112 includes an aperture 122 which
 enables a pin 124 to pass there-through to secure the handle on the screw
 30 through the aperture 46. Likewise, the handle 100 includes an aperture
 and a pin to secure it on the screw 30.
 The work bench vise of the present invention is ordinarily operated as
 follows. One of the handles 100, 110 is rotated which, in turn, rotates
 either one of the screws 30. The rotation of the screw 30 rotates the
 sprocket 50 and via belt 56 rotates the other screw 30 via its sprocket
 50. Thus, both of the screws 30 rotate at the same time, ordinarily,
 synchronously. As the user is utilizing one hand to rotate both screws 50,
 the user can use his other hand to hold the workpiece in between the two
 table members 24, 26. As the table members 24, 26 contact the workpiece,
 and especially if the workpiece has an irregular shape, the front table
 member 24 will contact the workpiece and the sprocket 50 will compress
 against the spring 64 and move away from the pin 62, thus engaging the
 clutch 70. If an irregular shaped workpiece is between the table portions,
 then one of the screws 30 will not rotate due to the clutching effect
 while the other will continue to rotate to clamp on the irregular shape of
 the workpiece. Once the workpiece is initially clamped and not over
 tightened, the individual screws can be shored up to give a firm grip onto
 the workpiece.
 While the above detailed description describes the preferred embodiment of
 the present invention, the invention is susceptible to modification,
 variation, and alteration without deviating from the scope and fair
 meaning of the subjoined claims.