Claims
- 1. A device for clamping a pair of workpieces together comprising:
- a pair of fastener heads, each defining an axially extending passageway, and each composed of an exterior portion having an exterior surface and defining slots extending axially from said surface, said slots forming segments in said head about said passageway, and an interior portion defining an interior surface having a camming surface such that movement of the head in an axial direction against a contact surface forces the segments in the head radially inwardly, thereby reducing the cross-section of the passageway, adjacent the exterior surface of the head, and
- means mounting the two heads for axial movement toward and a way from a contact position at which the camming surface of the two heads are simultaneously brought into contact with an associated contact surface, with further movement of the two heads axially toward one another acting to force the segments in each head radially inwardly, substantially the same extent, thereby reducing the cross-section of the passageway associated with each head, and causing clamping of a workpiece received in the passageway defined by each head,
- said mounting means including a shaft on which the two heads are carried, for relative movement toward or from one another, with relative rotation of the heads on the shaft, to a contact position in which the camming surface of one head is in contact with the camming surface of the other head, such that the camming surface of each head serves as the associated contact surface for the other head, where said shaft is rigidly attached to one head, and the other head is rotatably mounted on the shaft for axial movement thereon, with rotation of said other head.
- 2. A device for clamping a pair of workpieces together, comprising:
- a pair of fastener heads, each defining an axially extending passageway, and each composed of an exterior portion having an exterior surface and defining slots extending axially from said surface, said slots forming segments in said head about said passageway, and an interior portion defining an interior surface having a camming surface such that movement of the head in an axial direction against a contact surface forces the segments in the head radially inwardly, thereby reducing the cross-section of the passageway, adjacent the exterior surface of the head, and
- each of said heads further including an axially extending threaded region, in
- means mounting the two heads for axial movement toward and away from a contact position at which the camming surface of the two heads are simultaneously brought into contact with an associated contact surface, with further movement of the two heads axially toward one another acting to force the segments in each head radially inwardly, substantially the same extent, thereby reducing the cross-section of the passageway associated with each head, and causing clamping of a workpiece received in the passageway defined by each head, and
- said mounting means further including (a) a turnbuckle which engages the two threaded regions in opposite directions, such that rotation of the turnbuckle relative to the two heads moves the two heads simultaneously toward or away from one another, and (b) a pair of opposite contact surfaces designed to engage the associated camming surfaces of the two heads simultaneously, as the turnbuckle is rotated in one direction, to produce a simultaneous clamping action in each head.
- 3. The device of claim 2, wherein the mounting means further includes an inner sleeve which engages each of the head threaded regions for rotation therewith, and for axial movement with respect thereto, such that the two heads are maintained relatively non-rotating as the turnbuckle is rotated to move the two heads simultaneously toward and away from one another.
Parent Case Info
This application is a continuation-in part of copending patent application for "Clamp Device with Radially Split Head", Ser. No. 116,021, filed Nov. 3, 1987, now U.S. Pat. No. 4,804,197.
1. Field of the Invention
The present invention relates to split-head clamp devices for use in mounting, clamping or connecting workpieces.
2. Background of the Invention
Split head clamping fasteners have long been known, especially in the electrical connector art. Examples of such fasteners are found in U.S. Pat. Nos. 368,149; 1,809,381, 2,406,346; and 2,440,828 for holding an electrical wire which passes through that portion of the fastener which is a collet having a radially split head. The head has an increasing outer diameter, resembling a cone, which is to mate with a ferrule having a funnel shaped interior. The body of the collet is threaded and, after passing through the ferrule, is secured by a collet nut, which draws the conic head further into the ferrule and thereupon forces the segments of the split head radially inward against the work piece, an electrical cable. The ferrule itself is fastened to a main body, such as an electrical panel or battery.
Although this prior art type of fastener is useful, it is limited by the fact that it requires several mating parts as well as mechanical access to both ends of the ferrule; one end for inserting the collet and the other end for threading the collet nut. The fact that the fastener itself must be seCured to a primary support further limits its versatility. Also, the mechanical force necessary to draw the collet into the ferrule requires a threaded pair of parts and a hand tool for tightening the collet nut.
Swedish Pat. No. 87,205 discloses a clamping device in which tightening a nut on a threaded, slotted shaft reduces the interior shaft diameter, causing a clamping action of a tubular workpiece held in the shaft. U.S. Pat. No. 1,615,233 shows a similar type of clamp, in which tightening a nut on a conical, segmented head draws the segments together to produce a clamping action. U.S. Pat. No. 2,383,692 and French Patent No. 2,442,392 show similar types of split shaft clamps in which tightening a nut on a conical, segmented shaft produces clamping action on a workpiece held in the shaft.
More recently, U.S. Pat. Nos. 4,530,523 and 4,544,196 teach a clamping device in which clamping is produced by a pivoting action of threaded shaft segments. Here a nut carried on the shaft forcibly abuts a clamp surface, as the nut is tightened, and the reaction force is transmitted through the action of the bevelled nut threads to the bevelled shaft threads, to cause a slight pivoting in the clamp segments, to produce clamping of a workpiece held in the shaft.
It will be appreciated that all of the later-mentioned prior art clamp devices have a slotted shaft designed to produce a clamping action as a nut is advanced along the threaded shaft. One limitation of this construction is that clamping action requires interaction with a threaded nut, and thus precludes for example, the possibility of a simple screw-like shaft which can be engaged with a wall surface or the like, for clamping a workpiece to a wall surface. Secondly, each clamp member must be fully duplicated in a two-sided clamp, i.e., a clamp designed to clamp two workpieces together. Such devices are also limited to threaded engagement between a shaft and nut, and thus require turning in order to achieve clamping action.
3. Summary of the Invention
It is one object of the present invention to provide an improved clamping device which overcomes problems and limitations associated with prior art clamps.
A more particular object of the invention is to provide a clamp device in which clamping action is produced by clamping action of a segmented clamp head, rather than by closure of slotted shaft segments.
One advantage provided by this construction is that the clamping action can be achieved by advancing a screw-like shaft into a wall surface or the like, for clamping a workpiece to the wall surface.
Another advantage provided by the construction is that a two-sided clamp may be formed in which clamping action is achieved by interaction of clamping members on each side of the clamping device.
Still another advantage of this construction is that clamping can be achieved with threaded engagement between a shaft and tightening nut.
Providing a clamping device in which the clamping force is directed against a relatively narrow annular region of the workpiece is yet another object of the invention.
The clamping device of the invention includes a split head fastener composed of a head having exterior and interior surfaces, and a shaft attached to the head and extending substantially normally from the interior surface thereof, along a longitudinally extending central axis. The head defines a passageway extending inwardly along this axis from the exterior surface, and dimensioned for receiving a portion of such workpiece. The head further defines slots extending from the exterior surface generally axially toward but not to said interior surface, these slots forming segments in the head which function as clamping members.
A threaded member carried on the shaft for axial movement thereon, has a contact face designed to contact the inner surface of the head in an outer surface region thereof which is radially spaced from the region of attachment of the shaft to the head. Advancing the member along the shaft forces the contact surface against this outer surface region, forcing the segments in the head to pivot inwardly. This reduces the cross section of the passageway adjacent the exterior surface of the head, causing clamping of a workpiece received in the passageway.
In one general embodiment, the interior surface of the head includes a camming surface which typically is formed by an undercut in the interior surface, or by one or more projections from a planar interior surface. The contact surface of the tightening member can be substantially planar.
In a second general embodiment, the contact face of the tightening member includes a camming surface which extends from the contact face. This surface may also be formed as an undercut in the contact face or by one or more projections from a planar contact face. The interior surface of the contact face may be substantially planar.
In an embodiment intended for attaching a workpiece to a support surface or the like, the shaft is a threaded screw which can be advanced into the support by turning, and the interior surface includes a camming surface which extends from its outer surface region axially in the direction of the shaft. When the split head fastener is advanced toward the support, Contact of the camming surface with the wall produces pivoting action on the head segments, causing clamping of a workpiece in the fastener.
In a two-sided clamp of the invention, for use in clamping a pair of workpieces axially in tandem, the tightening member of one side of the clamp functions as the tightening member of the other side of the clamp, i.e., the two heads interact to apply opposed axial forces against one another's interior surfaces, to cause the segments in each head to pivot toward a clamping condition.
These and other objects and features of the invention will become more fully apparent when the following detailed description of the invention is read in conjunction with the accompanying drawings.
US Referenced Citations (9)
Foreign Referenced Citations (2)
| Number |
Date |
Country |
| 2442392 |
Jun 1980 |
FRX |
| 87205 |
Aug 1936 |
SEX |
Continuation in Parts (1)
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Number |
Date |
Country |
| Parent |
116021 |
Nov 1987 |
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Patent Grant
4940249
