GB1577925A - Cord clamp - Google Patents

Description

(54) A CORD CLAMP (71) We, ARROW-HART (EUROPE) LIMITED, a British Company of Plymbridge Road, Estover, Plymouth PL6 7PN, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following Statement: This invention relates to a cord clamp and to an electrical assembly incorporating such a cord clamp.

According to one aspect of the invention a cord clamp comprises a air of spacedapart, cord-locating means for locating two axially spaced-apart portions of a cord, abutment means positioned between, and fixed relative to each of, said cord-locating means so that the shortest cord path between the pair of cord-locating means follows a curved path around said abutment means, and resiliently flexible pressing means adapted to press a cord, following said shortest cord path, against said abutment means, and being flexible away from the abutment means to enable adjustment of the position of a cord in the cord clamp.

Suitably the pair of cord-locating means are disposed at an angle, e.g. 90 , to each other.

Typically the abutment means has a cordcontacting surface for resisting relative movement, at least in one direction of the cord path, between the abutment means and a cord pressed there-against. The cordcontacting surface may be roughened or may be provided with serrations or saw teeth.

The abutment means may be provided with a substantially convex surface against which a cord is adapted to be pressed.

The pressing means suitably comprises a resilient, flexible finger or blade positioned so as to form, in use, an acute angle with a cord pressed against the abutment means.

According to a further aspect of the invention there is provided an electrical assembly comprising a casing having an opening for receiving an electric cord and housing terminals for connection to conductors of the cord, and a cord clamp according to said one aspect of the invention.

The invention will now be described, by way of example, with reference to the drawings accompanying the Provisional specification, in which: Figure 1 is a section through a handle assembly for an electric appliance, Figure 2 is a section on the line II-II of Figure 1, Figure 3 is an enlarged view of a portion of Figure 1, and Figure 4 is a section on the line IV - IV of Figure 3.

Figure 1 shows a handle assembly, generally designated by the reference numeral 1, of an electrically-operated lawn mower.

This handle assembly comprises a metal tube 2 of circular cross-section, a hand grip 3 detachably connected to an open end 4 of the tube 2, and a plug member 5 removably inserted in the hand grip 3. The hand grip 3 comprises two parts 3a and 3b (see Figure 2) of generally U-cross-section and made of electrically insulating material which are either held together by screws (not shown) or welded, e.g. ultrasonically, together to define the casing of the hand grip 3. Within the casing there is housed an insert, generally designated by the reference numeral 6, and a switch comprising two fixed contact blades 7 and 8 mounted on a rib 9 of electrically-insulating material integrally formed with casing part 3a, and two further fixed contact blades 10 and 11 mounted on a further rib 12 of electrically-insulating material also integrally formed with the casing part 3a.A switch-actuating member 13, carrying a pair of metallic bridging contacts 14 and 15, is actuable by finger pressure against the resistance of a spring (not shown) to position the bridging contacts 14 and 15 in electrical and mechanical contact with the contacts 7, 10 and the contacts 8, 11, respectively.

The insert 6 consists of a head portion 16 and a shank portion 17 integrally formed therewith. The shank portion 17 comprises a pair of resilient arms 18, 19 which extend into a tubular end part 20 of the hand grip 3.

Radially-outwardly projecting portions 21, 22 are integrally formed at the free end of the arms 18, 19, respectively. Grooves 23, 24, of substantially V-cross-section open into the radially-outwardly facing surface of the portions 21, 22, respectively; one end of the grooves 23, 24 being open and the opposite end of the grooves 23, 24 having a flat, axially-facing abutment surface 25, 26, respectively. Seated in the grooves 23, 24 are radially-inwardly-projecting pressings 27, 28, respectively, formed in diametrically opposed portions of the metal tube 2, adJacent its open end 4. Each of the pressings 27, 28 has an axially-facing abutment surface 29, 30, respectively, which abuts against the abutment surface 25, 26, respectively, to prevent axial movement of the tube 2, in the direction indicated by the arrow A, relative to the tubular end part 20.

Movement of the tube 2 relative to the end part 20 in the direction opposite to that indicated by the arrow A is prevented by abutment of the open end 4 of the tube 2 against radially-inwardly-projecting flanges 31 integrally formed with the casing parts 3a and 3b at the axially-inner end of the tubular end part 20. The shank portion 17 of the insert 6 passes through an opening 32 defined by the flanges 31. The opening 32 is of non-circular cross-section, e.g.rectangular, to prevent turning of the insert 6 therein.

In order to detach the hand grip 3 from the metal tube 2, the hand grip 3 is first turned through approximately 90" relative to the tube 2 from the position shown in the drawings. There is an initial resistance to this turning movement since pressings 27, 28 are seated in the grooves 23, 24, respectively. However, during the initial part of the turning movement, the arms 21 and 22 are resiliently moved towards each other and the pressings 27, 28 are moved out of the grooves 23, 24, respectively. Once the pressings 27, 28 have been moved fully out of the grooves, 23, 24, respectively, the metal tube 2 can be moved axially relative to the end part 20 in the direction indicated by the arrow A to detach the tube 2 from the hand grip 3. Attachment of the tube 2 to the hand grip 3 can be easily performed by following the procedure outlines above in reverse.

An electric cable 82, having a pair of electric conductors 33 and 34 connected to terminals at the ends of the fixed contact blades 7 and 8, respectively, enters into the hand grip 3 through an opening 35 and is clamped in the head portion 16. As shown in Figures 3 and 4, the head portion 16 is in the form of an open box hving a pair of spaced-apart, parallel side walls 36, 37, a pair of spaced-apart, parallel end walls 38, 39, a bottom 80 and an open top 81.

Openings 40 and 41 are provided in the walls 36 and 38, respectively, and serve to locate opposite ends of the part 42 of the cable 82 positioned within the head portion 16. A curved, internal partition wall 43 obstructs a direct cord path between the openings 40 and 41 and defines one side of the shortest cord path between the two openings 40 and 41. A resilient blade or finger 44, integrally formed with, and projecting from, the end wall 39 presses the cable part 42 against a substantially convexly-curved surface 45 of the wall 43, thereby resiliently gripping or clamping the cable 82 in the head portion 16. The surface 45 is provided with means for deterring movement of the cable part 42 with respect to the wall 43 at least in one direction along the shortest cord path.In Figures 1, 3 and 4, the deterring means comprises saw teeth 46, although outer types of deterring means, such as ribs (not shown) could be used. The finger 44 is shown positioned so as to form an acute angle a with the cable part 42. This acute angle, together with the inclination of the saw teeth 46, deters movement of the cable 82 through the head portion 16 in the direction indicated by the arrow B (Figure 3).

Prior to securing the two casing parts 3a and 3b together, the resilient finger 44 may be manually moved out of contact with the cable part 42 thereby enabling the cable 82 to be freely moved through, and accurately positioned in, the head portion 16. In this case, access to the finger 44 is gained through the open top 81 of the head portion 16. If the two casing parts 3a, 3b are subsequently secured together, it is not possible thereafter to readjust the position of the cable 82 in the head portion 16.

However, if the two casing parts 3a, 3b are subsequently detachably secured together, e.g. screwed or bolted together, it is possible thereafter to separate the casing parts enabling either readjustment of the cable position in the head portion 16 or the removal of the cable 82 and replacement by another cable.

The insert 6 is suitably moulded in one piece from thermoplastics material. A rectangular aperture 47 is provided in the bottom 80 of the head portion 16 for the insertion of a tool during the moulding process to enble the forming of the underside 83 of the finger 44. The underside 83 of the finger 44 is thus spaced from the bottom of the head portion 16.

The plug member 5 comprises a pair of contact members 50 and 51 which make electrical and mechanical contact with the contacts 10 and 11, respectively. Electrical conductors 52, 53 of an electric cable 54 are securely connected to the contact members 50, 51, respectively. A cable clamp for the cable 54 is schematically shown at 55. In practice this cable clamp may be of similar construction to the head portion 16 described hereinbefore. A thermal cut-out (not shown) may be installed in the plug member 5.

A cord clamp according to the present invention may be employed in other electrical applications, e.g. as a cable clamp in an electric plug, or in non-electrical applications where it is desired to clamp a cord.

The handle assembly shown in the drawings accompanying the provisional specifica tion is described and claimed in our copending Application No. 27211/76.

WHAT WE CLAIM IS: 1. A cord clamp comprising a pair of spaced-apart, cord-locating means for locat ing two axially spaced-apart portions of a cord, abutment means positioned between, and fixed relative to each of, said cord locating means so that the shortest cord path between the pair of cord-locating means follows a curved path around said abutment means, and resiliently flexible pressing means adapted to press a cord, following said shortest cord path, against said abut ment means, and being flexible away from the abutment means to enable adjustment of the position of a cord in the cord clamp.

2. A cord clamp according to claim 1, in which the paid of cord-locating means is arranged so that the spaced-apart portions of a cord locating therein are disposed at an angle to each other.

3. A cord clamp according to claim 2, in which the said angle is substantially 90 .

4. A cord clamp according to any of the preceding claims, in which the abutment means has a cord-contacting surface for resisting relative movement, at least in one direction of the cord path, between the abutment means and a cord pressed there against.

5. A cord clamp according to claim 4, in which the cord-contacting surface is roughened.

6. A cord clamp according to claim 4, in which the cord-contacting surface is provided with serrations or saw teeth.

7. A cord clamp according to any of the preceding claims, in which the abutment means is provided with a substantially convex surface against which a cord is adapted to be pressed.

8. A cord clamp according to any of the preceding claims, in which the pressing means comprises a resilient, flexible finger or blade positioned so as to form, in use, an acute angle with a cord pressed against the abutment means.

9. A cord clamp according to any of the preceding claims, moulded from thermoplastics material in a unitary structure.

10. A cord clamp as claimed in claim 1, constructed and arranged substantially as herein described with reference to and as illustrated in Figures 3 and 4 of the drawings accompanying the provisional specification.

11. An electrical assembly comprising a casing having an opening for receiving an electric cord and housing terminals for connection to conductors of the cord, and a cord clamp as claimed in any of the preced

Claims (1)

1. ing claims.

   12. An electrical assembly according to claim 11, in which the cord clamp is within the casing.