GB2127515A

GB2127515A - Clamping devices

Info

Publication number: GB2127515A
Application number: GB08227343A
Authority: GB
Inventors: Porta Clifford Anthony Della
Original assignee: Premier Drum Co Ltd
Current assignee: Premier Drum Co Ltd
Priority date: 1982-09-24
Filing date: 1982-09-24
Publication date: 1984-04-11

Abstract

A first elongate member 2 (such as a support for a percussion instrument) has an end portion thereof received in a hollow end portion of a second elongate member 4 (such as a support), and is retained relative thereto by a clamping collar 6. The collar 6 has a clamping portion 8 which is clamped by means of a set screw 18 to a region of the member 2 not received within the end portion of the member 4, and a sleeve portion 12 which surrounds the end portion of the member 4 and which is clamped thereto by a further set screw 18. Abutments on the member 4 and the collar 6 limit the extent by which the member 2 can be inserted into the end portion of the member 4. The set screw 18 associated with the clamping portion 8 serves to clamp the member 2 only lightly to the collar 6, but can be replaced by a longer screw 16 which clamps the member 2 much more firmly. <IMAGE>

Description

SPECIFICATION Improvements in or relating to clamping devices The invention is concerned with improvements in or relating to clamping devices suitable for example for use in support stands for musical instruments or other manually operable apparatus.

It will be understood however that such use is mentioned as one of many possible examples and the present invention will find application wherever there is need to secure an elongate member, whether it is a rod or tube, for lengthwise and/or angular (for example rotary) movement with respect to a tubular sleeve within which the elongate member is adjustably received and which, when the correct adjustment is obtained, permits secure clamping of the components in the desired position.

The invention provides a clamping device for securing together in a desired relationship two elongate members, a first one of which is axially received within a second, hollow, member to an adjustable extent, comprising a clamping collar having a first clamping portion adapted to embrace and clamp the first member at a region thereof not received within the second member, lip portions of said second member being receivable within a sleeve or flange of said collar to an extent determined by an abutment means, and a second clamping portion adapted to secure said lip portions within the sleeve or flange.

The first clamping portion may comprise a partannular body member of said collar, a partannular clamping insert mounted in said body member for pivotal movement about a lengthwise axis to engage or disengage said first elongate member and a set screw, the degree of said pivotal movement into engagement with the first member being determined by the length of insertion of said set screw radially through the annular body member into contact with the clamping insert.

Advantageously, the second clamping portion comprises a second set screw radially inserted through said sleeve or flange of the collar into clamping contact with the lip portions of the second elongate member. Conveniently, the first mentioned set screw and the second set screw are of different axial lengths and may be interchanged so that less pivotal movement is imparted to the clamping insert of the first clamping portion when the shorter of the two set screws is used at that location and a greater degree of pivotal movement is imparted (i.e. a firmer clamping action is obtained) when the longer of the two set screws is used.

The invention will be further described with reference to an example of a clamping device for use in a support means for a musical instrument, for example cymbals. It will be understood that the description which is to be read with reference to the drawings, is given by way of example only and not by way of limitation.

In the drawings: Figure 1 shows a longitudinal sectional view of a clamping device; Figure 2 is a fragmentary view of the device of Figure 1; Figure 3 is a view of a clamping collar of the device in the direction of arrow A of Figure 1; and Figure 4 is a view in the direction of arrow B of Figure 3, partly in section for clarity.

The Figures show a clamping device for use in a support or stand for cymbals or the like. While the example is described in an upright orientation, it will be understood that the clamping device may be used for securing together two members as described below, in whatever orientation may be desired e.g. horizontal. Moreover, although the example described illustrates the device as securing together two members having circular cross-section since this permits the greatest adjustability of angular adjustment, i.e. rotary, it is within the scope of the invention to provide a clamping device for, say, square cross-section members allowing angular adjustment by 900 stages.

The Figures show a first elongate member 2, in the present example a hollow tube supporting a cymbal (not shown) at its upper end. A lower end of the member 2 is received within a second, hollow, tubular member 4 in a sliding fit.

A clamping collar indicated at 6 is fitted around the first member 2 at a zone selected according to the length of said member 2 which it is desired to be received within the second member 4, thus regulating the height at which the cymbal is positioned with respect to the musician. A first clamping portion 8 of the collar is arranged to embrace and clamp the member 2 in a manner to be described more fully below.

A second clamping portion (indicated at 10) of the collar 6 comprises a downwardly extending flange or sleeve 12 with an aperture 14 through which passes one of two set screws 1 6, 18 so as to engage in a captive flat-sided nut 20, in the present example having a square configuration. An end portion of the set screw is arranged to impinge against an abutment 22 provided upon a swaged portion 24 of the member 4, when the portion 24 is received within the sleeve 1 2.

The second clamping portion 10 is shown on a slightly larger scale in Figure 2, in which the abutment 22 is shown having a dished surface to improve contact with the set screw 1 8. When the two members 2, 4 are engaged in this manner, all tendency for relative rotary movement between them is prevented.

Figures 3 and 4 illustrate the first clamping portion 8, which comprises a part-annular body member 26 which partly encircles the first elongate member 2 (omitted from Figure 4 for ciarity) and a clamping insert 28 mounted in the body member 26 for pivotal movement about an axis 30. A square nut 32 is captive in a recess of the insert 28 adjacent an aperture 34 in a narrow extension wall portion 36 of the body member 26.

Co-axial with the internally threaded aperture of the nut 32 is an aperture 38 in the insert 28 which is also internally threaded at its opening adjacent the nut 32, but is partially blanked off at 40 for the remainder of its length. Alternatively, the aperture 38 may be replaced by a shallow, blind, threaded passage. In either case, the insertion of the set screw 18 until its stop flange 42 abuts the wall portion 36 results in the externally threaded portion thereof being received within the nut and entering the internally threaded portion of the passage or aperture 38, exerting little or no pressure upon the blanked-off portion 40. Axial adjustment of the member 2 in the collar 8 is therefore still possible.

However, if the longer set screw 1 6 is inserted, then the leading tip thereof is able to impinge against the portion 40 and to cause the insert 28 to move about the axis 30 into its dotted line position 28' in which the member 2 is firmly clamped and no axial adjustment is possible until the set screw is withdrawn.

The operation of the device is as follows.

Where a musician wishes to interchange instruments, for example cymbals, drums and the like, of the kind supported upon a stand, for example a support tripod, it is not necessary for there to be a separate tripod for each instrument.

It is therefore the custom to clamp the first tubular member, which carries the selected cymbal, to the hollow tubular member that is part of the tripod or stand. When it is desired to exchange the cymbal for an alternative instrument, the first cymbal will be removed from the stand and replaced, using the same stand. However, where this is necessarily carried out at speed, say between numbers in a dance hall, there must be the minimum of adjustments made. The use of the clamping device as described above ensures that each cymbal is received in the stand at appropriate and correct height without adjustment.

The two set screws in the description 1 6 and 1 8 are readily identifiable since the longer one, 16, is hand-operable in the manner of a thumb screw and the shorter one, 1 8 is operated by a square section drum key.

Insertion of the screw 16 in the aperture 34, through the nut 32 so as to exert pressure on the abutment 40 and move the insert 28 into firm contact with the first tubular member 2, secures the collar firmly thereto so that whenever that particular first member 2 is inserted into member 4, the extent of the insertion is predetermined.

Thus the first clamping portion may be said to act as a "memory lock". The second screw 1 6 simply serves to retain the two members 2, 4, in their clamped positions.

Should it be desired to dispense with the socalled "memory lock", the set screws may be interchanged so that the shorter screw 1 8 is received in the nut 32. In this case, the screw is not of sufficient length to pivot the insert into firm contact with the member 2 and thus axial adjustment is possible, since the contact between the insert 28 and the member 2 is frictional and permits a degree of slippage under manual pressure.

Various modifications may be made within the scope of the invention.

Claims

1. A clamping assembly comprising a first elongate member having an end part thereof received within a hollow end portion of a second elongate member, a clamping collar including a clamping portion which embraces a region of the first member which is not received within the second member and a sleeve portion which surrounds said end portion of the second member, first clamping means operable to clamp the clamping portion of the collar onto the first member, a pair of abutments on the collar and the second member respectively which are mutually engageable to determine the amount by which the first member can be inserted into the second member, and second clamping means operable to clamp the sleeve of the collar to the second member.

2. A clamping assembly as claimed in claim 1, wherein the first clamping means includes a set screw which is received by the clamping portion of the collar and which clamps the first member to a degree dependent upon the length to which it is thus received.

3. A clamping assembly as claimed in claim 2, wherein the set screw is one of two such screws which can be received interchangeably by the clamping portion of the collar, the set screws being of different lengths with the shorter one providing a light frictional clamping of the first member within the collar whereby the first member may be moved relative to the collar in the direction of its elongation, and the longer one providing firm clamping of the first member within the collar.

4. A clamping assembly as claimed in claim 3, wherein the two set screws have different heads for ready identification.

5. A clamping assembly as claimed in claim 4, wherein one set screw has a square head for operation by a drum key or the like, while the other set screw has a head which is configured for hand-operation in the manner of a thumb screw.

6. A clamping assembly as claimed in claim 5, wherein said one set screw is the shorter of the two screws.

7. A clamping assembly as claimed in any preceding claim, wherein the first clamping means includes an insert which is pivotable relative to a main body of the clamping portion of the collar about an axis extending in the direction of elongation of the first member, the insert extending part-way around said region of the first member.

8. A clamping assembly as claimed in claim 7 when appended to any one of claims 3 to 6, wherein a pair of aligned internally threaded openings are provided in the main body and the insert respectively, through which extends the set screw in use at a particular time, the opening in the insert being at least partially blanked off so as to define an abutment against which only the longer of the set screws can bear to pivot the insert relative to the main body.

9. A clamping assembly as claimed in any preceding claim, wherein the second clamping means comprises a set screw which is inserted through an opening in the sleeve portion of the collar into engagement with said end portion of the second member.

10. A clamping assembly as claimed in claim 9, wherein a dished abutment is provided on the second member for engagement by the set screw.

11. A clamping assembly as claimed in any preceding claim, wherein a plurality of such first members and a plurality of such clamping collars are provided for interchangeable engagement with the second member, each first member having a respective one of the clamping collars clamped thereto at a predetermined location along its length.

12. A clamping assembly as claimed in any preceding claim, wherein the second member is a stand and the first member is a support for a percussion instrument or the like.

1 3. A clamping assembly substantially as hereinbefore described with reference to the accompanying drawings.