Clamp for workpieces

Details Clamp for workpieces Clamp for workpieces

1999-10-12

2001-02-20

Watson, Robert C. (Department: 3723)

Work holders

Relatively movable jaws

Three coacting work grippers

C269S231000, C269S235000, C269S258000, C269S268000

Reexamination Certificate

active

06189878

ABSTRACT:

FIELD OF THE INVENTION
This invention relates clamping devices; more particularly, it relates to a clamp for pressing a first extended plate-like or bar-shaped workpiece in its longitudinal direction against a bearing surface of a second workpiece.
BACKGROUND OF THE INVENTION
A workpiece is known from German utility model patent G 88 00 461.9, with which an edging strip can be mounted on the narrow, circumferential edge of a table-shaped workpiece. Clamping jaws are provided in a clamping jaw support known as a yoke. The yoke has forked legs. The clamping jaws are pivot-mounted about parallel axes through the forked ends of the legs of the yoke.
In this device the workpieces to be clamped the open space between the legs of the yoke.
Another workpiece clamp is disclosed in U.S. Pat. No. 5,350,163. It has clamping jaws which can be adjusted by sliding in guide grooves. These guide grooves are arranged on a clamping jaw support in symmetrical and V-shaped fashion relative to one another. When clamping a workpiece, the clamping jaws move in the direction of the tapering guide grooves. This results in a wedge effect, which primarily serves to clamp the workpiece. The V-shaped arrangement of the guide grooves makes it possible to use the to clamp a relatively wide range of workpiece thicknesses. However, this device is also limited to workpieces which can only extend freely on the side of the clamping jaw support on which the jaws are mounted.
The function of this device disadvantageously requires that the clamping jaws arranged in the symmetrical guide grooves be positioned exactly opposite one another when approaching a workpiece. If the clamping jaws are not exactly opposite one another, this leads to a situation where one of the clamping jaws moves in one direction in its guide groove and the opposite clamping jaw in the other direction, when pressing on the workpiece. This causes the workpiece to rotate and prevents it from being clamped. In order to be able to handle this clamp clip despite these difficulties, it is provided with an auxiliary device with which the clamping jaws can always be moved in the guide grooves in a symmetrical position relative to one another.
In order for the bearing pins of this device to always remain in a vertical position, the guide grooves and the bearing pins guided in them must be manufactured with great precision. Any play in the bearing pin caused by wear quickly makes the device unserviceable. The particular accuracy and care involved in the manufacture of the numerous individual parts required and in the assembly of this device lead to high manufacturing costs. The auxiliary device required to symmetrically guide the clamping jaws further increases manufacturing costs. and also increases the weight of the device which makes handling difficult.
A general object of the present invention is to overcome certain disadvantages of the prior art and to provide a clamp with which long plate-shaped and/or bar-shaped workpieces can be clamped, where both the first and second workpieces can be of plate-shaped design.
SUMMARY OF THE INVENTION
In accordance with this invention, a workpiece clamp is provided which is adapted to press a first extended plate-like or bar-shaped workpiece in its longitudinal direction against a bearing surface of another workpiece which may also be plate-like or bar-shaped.
This is accomplished by clamping jaws are mounted on a clamping jaw support and which extend, they project away from the plane of the support for clamping a first workpiece. This results in an open space, which is not restricted on the sides, for accommodating a second plate-shaped workpiece. Thus, a second plate-shaped workpiece can not only extend freely in the axial direction of the jaws but can also extend from one side to the other of the plane of the clamping jaw support.
Thus narrow edging strips and also large, plate-shaped workpieces can be clamped.
Further, in accordance with this invention, a workpiece clamp is provided which comprises a retaining frame, a chucking tool for generating a pressure force which can be transmitted to the bearing surface of a second workpiece, at least one counter-holding device consisting of a clamping jaw support with a U-shaped opening and two clamping jaws with spiral-shaped clamping surfaces pivot-mounted in stationary fashion on the clamping jaw support, which are positioned symmetrically opposite one another and mounted parallel to one another, such that the opening is located between the clamping jaws.
Further, in accordance with this invention, the clamping jaws are rotatably and tiltably mounted on bearing pins which permit large clamping forces to be generated even if the bearing pins only one side spread apart. Due to the tilting mounting of the clamping jaws on the bearing pins, the clamping surfaces can always position themselves accurately on the first workpiece and good transmission of the clamping force is assured.
The radial distance of the clamping jaws preferably displays a spiral-shaped profile of the kind that permits the clamping force of the clamping jaws to always be applied at the same angle A to workpieces of different thickness. The range of angles through which the clamping surface extends is divided into angular steps of equal size. The radial distance from the rotational axis to the clamping surface increases by the same amount with each angular step. Angle A is preferably small, in order to be able to achieve high clamping forces with a small angle A. However, it must not approach a value of 0° too closely, because the manufacturing tolerances and elastic deformations of the components could prevent the workpiece from being clamped tightly enough and cause it to slip through the clamping jaws.
Of course, the radial distance from the rotational axis to the clamping surface need not increase in equal angular steps and by the same amounts each time. The amounts can increase or decrease with each angular step. It is also possible to switch between an increasing and decreasing amount. This can be dependent on the combination of materials which make up the surfaces of the clamping jaws and the workpieces to be clamped, the two of which form a friction pairing.
The angular range of the clamping surfaces for clamping a workpiece, can be provided with limiting elements which restrict the rotation of the clamping jaw to this angular range.
Suitable pairs of clamping jaws can be provided in order to clamp different workpieces. They are simple to exchange.
The angular range required for a clamping surface is governed by the use of the workpiece clamp. If, for example, workpieces in a thickness range of roughly 1 mm to 40 mm are to be clamped, a clamping surface in an angular range of 280° is sufficient. If only workpieces of equal thickness are to be clamped, an angular range of roughly 20° is sufficient. In the latter case, the clamping jaw can be of very small design.
Due to the opening in the clamping jaw support in the region between the pivotal arrangements, long workpieces can extend through the clamping jaw support. This measure also makes it possible for the counterholding device to clamp long workpieces with an angled face. This expands the possible applications of the workpiece clamp.
The bearing pins are expediently of convex shape in order to enable tilting motion of the clamping jaws. The play between the clamping jaws and the bearing pins can be relatively great. This does not impair the function of the workpiece clamp and also drastically reduces the manufacturing costs.
A fixing element is advantageously provided on each of the bearing pins in order to prevent the axial shifting of the clamping jaws. This element can, for example, be an individual component which can be mounted in the region of the free ends of the bearing pins. These fixing elements can be easily removed for the simple procedure of switching the clamping jaws. Pairs of clamping jaws with differently shaped clamping surfaces or for different thickness ranges can be switched very easily.
In another configuration, th

Affiliated with

Also associated with

Rating

Clamp for workpieces does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Clamp for workpieces, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Clamp for workpieces will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2568270