Clamp

A clamp for connecting flanged tubes comprising a pair of tangs having a tampered groove around their insides to engage the flanges. One of the tangs is provided with a pivotally connected screw, which passes through an aperture in one end. A nut attached to the screw holds the tangs in position. To prevent rotation of the tang about the screw, the lower shaft of the screw is provided in a non-circular shape, with the aperture in the tang being provided in mating conformity.

This application claims the benefit of United Kingdom Patent Application Serial Number GB0719972.2 filed on Oct. 12, 2007 and United Kingdom Patent Application Serial Number GB0806433.9 filed on Apr. 9, 2008.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to clamps, particularly though not exclusively for connecting flanged tubes for use in the pharmaceutical, food and related industries.

2. Description of the Related Art

In my earlier patent, GB 2361753, I describe a clamp for connecting flanged tubes. This clamp is very successful for connecting flanged tubes of up to and including approximately four inches in diameter. However, for clamps of a larger size, I found that the hinge starts to fail on prolonged use.

While using the same screw and nut arrangement at both sides of the clamp provides a secure clamp, such a clamp is awkward, difficult to use and cannot be used one-handed.

SUMMARY OF THE INVENTION

The object of the present invention is to provide an improved joint for a clamp or the like.

According to the invention there is provided a joint for a clamp or the like, having a pair of tangs, the joint including a screw pivotally connected to a first tang, and having a section of non-circular shaped shaft extending from the pivotal connection, the second tang having a complimentary aperture for receiving the screw, the fit between the shaft and the aperture preventing significant rotation of the second tang around the screw.

Preferably, the shape of the shaft is essentially square, with the aperture in the tang also being square. Alternatively, the shaft may be triangular, pentagonal, hexagonal or any other non-circular shape.

The joint further includes a nut for connection to the thread of the screw to hold the tangs in position.

Preferably, the second tang may have a projection at least partially surrounding its aperture with the nut having a complimentary indentation. Typically the projection and indentation will be substantially conical.

Advantageously, the second tang may be provided with at least one projection to mate on the first tang, to prevent over-tightening of the clamp tangs.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring toFIGS. 1 and 2, the clamp thereshown is for clamping flanged tubes, particularly for use in the pharmaceutical and food industries.

The clamp comprises a pair of substantially semi-circular tangs2,4. The tangs have a tapered6groove running around the inside of them, to engage the flanges of a pair of flanged tubes with a seal therebetween, not shown, holding the tubes in sealing relationship with each other.

At one side, the tangs2,4are held together with a nut10and screw12as described in my earlier patent GB 2361753. One tang2has a clevis20defined by two lugs22. Each had an overhung recess24into which the crosshead26of the screw12clips. A cross-bar28connects the lugs remote from their tang, whereby the screw is limited in its angular displacement about the recess. The cross-bar also stabilizes the lugs against relative displacement under load when the nut is tightened.

The other tang4has a part conical formation30on lugs32defining a clevis34. The nut10has a complimentary conical recess36. Engagement of the formation30in the recess36restrains the lugs from separating under load as the nut is tightened. Mutual approach of the tangs is limited by projections38on the lugs32towards the lugs22to avoid over-tightening.

The other ends40,42of the tangs2,4are also held together with a nut44and screw46. The screw46is held captive between a pair of lugs48defining a clevis50in one of tangs2. The screw46is provided with a ring52which fits in the clevis50held in position by a pin51. The screw is provided with a section of lower shaft53of square cross-sectional. The other tang4is provided with a square aperture54for receiving the screw46. Thus, use of the square shaft53and square aperture54, prevents significant rotational movement of the tangs2,4rendering the clamp stronger and easier to use. It is not essential that the shaft and aperture are square; they could be triangular, hexagonal or any non-circular shape.

The nut44is provided with an internal thread for engagement with the screw46. This enables tightening and loosening of the nut of the screw and thus limited movement between the two tangs.

The aperture54is surrounded by a conical projection68with a complimentary conical indentation70in the nut44centering the nut on the tang and stabilizing the aperture. The tang4is also provided in projections72to prevent over-tightening of the nut44onto the screw46.

The invention is not intended to be restricted to the details of the above described embodiment. For instance, this connected nut and screw arrangement can be used on any form of clamp, including a pinch clamp.