GB2095051A

GB2095051A - A cable gland

Info

Publication number: GB2095051A
Application number: GB8207495A
Authority: GB
Original assignee: MICROFLOW UK Ltd
Current assignee: MICROFLOW UK Ltd
Priority date: 1981-03-14
Filing date: 1982-03-15
Publication date: 1982-09-22

Abstract

A cable gland comprises two parts 1 and 2 moulded from synthetic plastics material such as nylon. Part 1 defines a bore through which the cable in use extends, and from which projections 7 extend. Part 2 comprises a ring defining a frusto conical bore. As part 2 is pushed over projections 7 of part 1 these projections are progressively pushed into the surface of a cable extending through the parts and grip the cable. A lip extending around the surface of the bore through part 1 provides a waterproof seal. Part 1 is externally shaped for reception by a piece of equipment to which the cable leads. <IMAGE>

Description

SPECIFICATION A cable gland The present invention relates to a cable gland particularly, but not exclusively, for the cable inlet to an electric motor.

in one known electric motor cable inlet the cable passes through a multipart gland moulded from synthetic plastics material. Two of the parts are formed with complementary screwthreads, one internally and the other externally, so that a resiliently deformable "olive" placed between them can be compressed into the sheath of a cable extending through them to grip the cable tightly and provide a waterproof seal. The internally screwthreaded part is also externally screwthreaded so that a further internally screwthreaded part can be screwed onto it to clasp between these parts a suitably apertured metal plate. This plate is in turn slotted into specially formed slots in the electric motor housing. The overall arrangement is difficult and expensive to manufacture and complicated, expensive and time consuming to assemble.

According to the present invention there is provided a cable gland for a cable inlet in a piece of equipment comprising a first part defining a bore through which the cable in use extends, and a plurality of resiliently deformable projections extending around one end of the bore and a second part adapted to be pushed over the resiliently deformable projections so that in use the projections are pressed into a cable extending through the bore to grip it, one of the parts being externally shaped for reception by a piece of equipment.

A preferred embodiment of the invention may comprise any one or more of the following preferred features:- (a) One or both of the parts are moulded from synthetic plastics material, (b) The internal surface of the bore through the first part comprises an upstanding projection which, in use, is pressed into the cable extending through the bore to provide a waterproof seal, (c) There are four regularly spaced projections extending from one side of the bore, (d) A reinforcing web extends between the external formation and the material defining the bore, (e) The second part comprises a ring which defines a frusto conical bore therethrough such that as the ring is pushed further onto the projections with the larger diameter side of the bore being pushed out first the force pressing the projections inwardly increases, (f) The first part is externally shaped for reception by a piece of equipment.

In order that the invention may be more clearly understood, one embodiment thereof will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 shows a perspective exploded view of a cable gland in accordance with the invention, Figure 2 shows a cross-sectional view through the two parts of the gland shown in Figure 1, and Figure 3 shows a partial diagrammatic end elevational view of an electric motor incorporating a cable gland of the type shown in Figures 1 and 2.

Referring to Figures 1 and 2 the cable gland comprises a first part 1 and a second part 2. Each part is moulded from a suitable synthetic plastics material such as nylon, polyethylene or polyurethane. Part 1 comprises an external, rectangular, integral flange formation 3. On one side of this flange formation 3, a substantially cylindrical projection 4 defining a substantially cylindrical bore 5 extends. A strengthening web 6 is disposed between formation 3 and the cylindrical projection 4.

On the other side of the formation 3 to the projection 4, four projections 7 extend. These projections are regularly spaced around a substantially cylindrical envelope. A small upstanding circular projection 8 is formed on the internal surface of the bore 5 extending through the substantially cylindrical projection 4. This projection 8, in use provides a waterproof seal.

Part 2 comprises a ring whick defines a frusto conical bore 9. The nature of the bore is most clearly seen in Figure 2. A gland is fixed to a cable by first of all pushing the cable through part 1. A certain amount of resistance to this will be experienced because of the existence of the circular upstanding projection 8. Part 2 is then threaded onto the free end of the cable and with its larger diameter end of the bore 9 leading is pushed over the four projections 7. As part 2 is progressively pushed onto projections 7 the decreasing diameter of bore 9 causes the projections 7 to be progressively pushed into the external surface of the sheath of the cable extending through the parts. When part 2 is completely pushed onto the projections 7 so that its leading face abuts the adjacent face of formation 3, the projections 7 firmly grip the cable.

The gland and cable assembly can then be installed in the motor casing simply by sliding the rectangular formation 3 into the slots in the casing provided for this purpose. Referring to Figure 3, the motor casing part in which the slots are formed, which is referenced 10, is fixed to the remainder of the casing 11 by means of screws 12. The extent of the slots in the casing part 10 is indicated by dotted lines 1 3.

It will be appreciated that the above described gland provides an inexpensive and readily assemblable cable inlet for electrical motors and other types of electrical equipment. It will also be appreciated that the above gland has been described by way of example only and that many variations are possible without departing from the scope of the invention. For example, the number, distribution and shape of the projections 7 could be changed as desired, the shape as well as the already mentioned dimensions of the formation 3 could also be changed as desired. Also, the upstanding circular projection 8 could be dispensed with if desired and in fact dispensing with it may in some cases by positively beneficial particuiarly where the cable extends through the bore 5 with a very close tolerance.

Claims

1. A cable gland for a cable inlet in a piece of equipment comprising a first part defining a bore through which the cable in use extends, and a plurality of resilient deformable projections extending around one end of the bore and a second part adapted to be pushed over the resiliently deformable projections so that in use the projections are pressed into a cable extending through the bore to grip it, one of the parts being externally shaped for reception by a piece of equipment.

2. A cable gland as claimed in Claim 1, in which one or both of the parts are moulded from synthetic plastics material.

3. A cable gland as claimed in Claim 1 or 2, in which the internal surface of the bore through the first part comprises an upstanding projection which, in use, is pressed into the cable extending through the bore to provide a waterproof seal.

4. A cable gland as claimed in Claim 1, 2 or 3, in which there are four regularly spaced projections extending from one side of the bore.

5. A cable gland as claimed in Claim 1, 2, 3 or 4, in which a reinforcing web extends between the external formation and the material defining the bore.

6. A cable gland as claimed in any preceding claim, in which the second part comprises a ring which defines a frusto conical bore therethrough such that as the ring is pushed further onto the projections with the larger diameter side of the bore being pushed out first the force pressing the projections inwardly increases.

7. A cable gland as claimed in any preceding claim, in which the first part is externally shaped for reception by a piece of equipment.

8. A cable gland for a cable inlet in a piece of equipment substantially as hereinbefore described with reference to the accompanying drawings.