Work holders – Relatively movable jaws – With means to align coacting jaw faces
Reexamination Certificate
2000-06-05
2001-10-09
Watson, Robert C. (Department: 3723)
Work holders
Relatively movable jaws
With means to align coacting jaw faces
C269S170000, C269S171500
Reexamination Certificate
active
06299152
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a workbench having clamping jaws which rest on two parallel beams and of which at least one can be displaced in the direction of the other clamping jaw by means of drive members which are associated with each beam and can be operated individually.
Workbenches of this type are known in various design forms. Thus, for example, in DE-C2 44 18 687 and DE-C2-44 18 688, a fold-up workbench having two clamping jaws is described. One clamping jaw can be moved along the beams by means of two spindle drives which can be operated by a hand crank.
The content of these German patent references is hereby incorporated by reference herein.
One problem is known for these types of workbenches. It is difficult to provide a hands-free operation workbench that also would be capable of clamping non-prismatic workpieces.
SUMMARY OF THE INVENTION
This problem is first solved by providing a workbench constructed in accordance with the present invention. In that regard, one object of the present invention is to provide a workbench that permits hands-free operation and yet ensures the capability of clamping non-prismatic workpieces. In one embodiment, a workbench of the present invention has at least a pair of clamping jaws that rest on two parallel beams wherein one of the clamping jaws can be displaced in the direction of the other clamping jaw by drive members associated with each beam. The drive members can be operated individually or simultaneously. The drive members each have a drive which can be operated step by step and can be operated together or individually with one foot of an operator by a double lever technique. As a result of this configuration, the clamping of workpieces can be carried out in the simplest manner with the hands of an operator free. The workpiece can therefore be held by the operator in the position in which it is to be clamped. The displaceable clamping jaw is moved in the direction of the other clamping jaw by means of a foot operation. By the arrangement of a foot-operable double lever construction the drive members of each beam for the displaceable clamping jaw can be operated individually, which also makes it possible to clamp nonprismatic workpieces. For this purpose, the double lever is formed such that each individual lever can be operated in order to operate a drive member for the clamping jaw, and both drive members can also be operated at the same time, for uniform parallel displacement of the clamping jaws.
In one embodiment, the drive has a pulling or pushing rod that is secured to the clamping jaw and that can be displaced step by step or incrementally by a latching or clamping portion that in turn can be displaced by a pedal. A clamping or latching drive for the displaceable clamping jaw is thus provided, such as is known, for example, from cartridge pressure-emptying devices. By means of foot-operation of one or both foot levers of the double lever, the pulling or pushing rod is displaced step by step by latching or clamping portions in the direction of the clamping position of the workpiece.
In one embodiment, the clamping or latching drive further includes a releasable reverse-pressure lock. The latter can also be formed as a latching or clamping portion. In order to release the clamping position again, this reverse-pressure lock can be released, after which the clamping jaw can be displaced back again in the direction of the original position.
In one embodiment, the reverse-pressure lock is releasable by a reverse pedal operation. Provision is therefore made, for example, for a forward displacement of the clamping jaw into the clamping position to be achieved by pressing down the pedal or both pedals, and for release of the reverse-pressure lock to be achieved by lifting the pedal. Thus, both the clamping and the releasing of the workpiece after it has been worked on can be carried out with the hands free.
In one embodiment, the latching or clamping portion is further displaceable by an operating lever. In one embodiment, the operating lever is coupled to the pedal by a drive rod. In this case, preference is given to an arrangement in which an operating lever which is connected to a pedal by way of a drive rod is associated with each drive of the clamping jaw. In order to displace the pulling or pushing rod, the respective operating lever can be connected, for example in a pivotable manner, to the latching or clamping portion. However, it is also conceivable to act on the latching or clamping portion merely by means of the operating lever and, in this way, to achieve a displacement.
In one embodiment, the operating lever enters into a driver opening in a locking portion to release the reverse-pressure lock. By means of an appropriate displacement of the operating lever—as already mentioned, preferably by means of a reverse pedal operation—the locking piece is dragged along by way of the driver opening in such a way that this locking portion is pivoted or displaced into a position which releases the pulling or pushing rod. After this, the clamped workpiece is released. Furthermore, when the reverse-pressure lock is released, the clamping jaw can be displaced back again.
In one embodiment, the double pedal is disposed approximately at the center of a cross-member of the workbench. It proves to be particularly advantageous in terms of operation for the double pedal to be shaped like a gateway. By pressing down one or both pedals by means of foot operation, the clamping jaw is displaced forwards, as described. In order to release the reverse-pressure lock as a result of a reverse pedal operation, the foot passes through the double-pedal gateway and acts on the underside of the pedals by pulling the pedals. In one embodiment the drive rod and be pivoted in each case on a pivoting lever, the lever being mounted on a shaft which can be rotated by the foot pedal. The lever is disposed in the region of a supporting leg and extends in the U-shaped space in the supporting leg, which is shaped as a U-section. The drive rods coupled to the operating levers of the respective drives are thus located in a hidden position within the U-shaped spaces in the supporting legs. In one embodiment the clamping or latching drive is disposed approximately at the centre of the beam, underneath a bottom sliding bearing formed by a U-shaped beam section.
In one embodiment, the other clamping jaw can be mounted on the beams so that it can be moved by a spindle. This provides greater variability in the clamping area. In this case, this clamping jaw can be moved in a known manner along the beams in the direction of the one clamping jaw by means of two spindle drives which can be operated by a hand crank. In this case, it proves to be particularly advantageous for a beam section carrying the other clamping jaw to be capable of being pivoted up into a 90° position. This 90° position of the other clamping jaw can preferably be achieved only when the one clamping jaw is displaced completely back. In one embodiment, the other clamping jaw, when in the pivoted-up position, can be engaged against the broad face of the foot-operated clamping jaw. It is therefore possible for workpieces to be clamped vertically as well, for example in order to work on the sides thereof. In this case, clamping is carried out by means of the above-described spindle displacement of the pivoted-up clamping jaw.
The inventive features described are preferably provided on a fold-up workbench, such as is used in particular in the do-it-yourself sector. In this respect, it is proposed to make it possible for the supporting legs of the workbench to be folded into a position parallel to the beams and, in the position of use, to be locked to the beams. However, suitable configurations on professional workbenches are also conceivable.
REFERENCES:
patent: 738055 (1903-09-01), Newnam
patent: 1673381 (1928-06-01), Van Berkel
patent: 2424313 (1947-07-01), Heinrich
patent: 2892369 (1959-06-01), Millet
patent: 4057239 (1977-11-01), Hopf et al.
patent: 4154435 (1979-05-01), Al
Noniewicz Zbigniew
Sangmeister Gerhard
Schiff & Hardin & Waite
Watson Robert C.
Wolfcraft GmbH
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