GB1577946A - Protective coverings for externally threaded members - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO PROTECTIVE COVERINGS FOR EXTERNALLY THREADED MEMBERS (71) We, TUCKER FASTENERS LI MITED, a British Company of Walsall Road, Birmingham, 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 is concerned with improvements in or relating to protective coverings for externally threaded members and is especially, but not exclusively, concerned with coverings for use in protecting such members from paint or other coatings during manufacture of an article.

It is customary in the manufacture of a variety of articles, for example motor car bodies and housings for electrical equipment, to apply paint (or, in the case of the undersides of car bodies especially, nondecorative protective coatings) by a process involving dipping the article in a liquid coating material, or spraying it with such a material, and in some cases subsequently passing the article through a stoving oven at an elevated temperature to effect or hasten hardening of the material. When externally threaded members, e.g. bolts, have been assembled on the article, for example by welding, before a coating process as just referred to, and they are to have nuts threaded on to them afterwards, it is desirable to protect the externally threaded members from having the paint or other coating material applied to them.For this purpose, the members can be temporarily masked, for example by adhesive tape, but the application of tape and its removal is a time-consuming operation requiring a high degree of manual dexterity.

In patent specification 1252930 there is described a plastics plug which can be used for temporarily plugging an internally threaded hole to protect the thread from paint or other coating material and which can be inserted by pushing it into the hole readily removed with the aid of a screw driver.

It is one of the various objects of the present invention to provide a protective covering which can readily be applied to an externally threaded member to protect the thread from paint or other coating material during manufacture of an article and readily removed when it has served its purpose.

There is hereinafter described in detail to illustrate the invention by way of example a tubular plastics covering which can be used as protection for an externally screwthreaded member, which is easy to apply, and which can readily be removed from the member after a painting or other coating operation. This illustrative covering comprises a sleeve portion, closed at one end and open at the other, with resilient inwardly projecting thread-engaging portions in the form of longitudinal fins adapted to hold the covering on a member the thread of which falls within a range of thread diameters. The illustrative covering also has an outwardly flared, conical, skirt at its open end which can bear resiliently on the surface of an article from which the member projects.

The illustrative covering has two grooves diametrically opposite one another and running along the length of the sleeve portion provide longitudinal lines of weakness at one at least of which the portion will split if force is suitably applied in attempting to remove it from the threaded member. The illustrative covering has a flat tab projecting axially from its closed end to assist the application of force in a direction to facilitate such splitting.

The illustrative covering can conveniently be pushed on to a threaded member until it abuts the surface of an article from which the member projects and thus keep the thread clean and protect it from any mate rial with which it might otherwise become coated during further stages of manufacture of the article. If such stages include passing the article through a hot oven, the sleeve portion of the covering may split at one of the lines of weakness of its own accord. In any event, it can subsequently be readily removed by grasping the tab and tugging it to one side.

The invention provides, in one of its several aspects, a plastics protective covering adapted for application to an externally threaded member, to keep the thread clean during manufacturing operations, comprising a sleeve portion, closed at one end and open at the other, with a plurality of resilient inwardly projecting threadengaging portions adapted to hold the covering on a threaded member to which it is applied, the thread-engaging portions extending lengthwise of the sleeve portion and being symmetrically disposed around the inner wall of the sleeve portion generally tangentially to a notional cylinder of small radius coaxial with the sleeve portion.

Preferably, as in the case with the illustrative covering, a covering in accordance with the invention has at least one longitudinal line of weakness running along its sleeve portion at which the portion will readily split to facilitate its removal from a threaded member when the covering has served its purpose.

Preferably, a covering in accordance with the invention is made by injection moulding of a suitable thermoplastic resilient synthetic resinous material, for example nylon (e.g. type 66), polyethylene or polypropylene; nylon type 66 is preferred where the covering is to protect a thread of a painted article which is to pass through a stoving oven.

The above and other of the various objects and several features of the invention will become more clear from the following description, to be read with reference to the drawing filed with the provisional specification, of the illustrative protective covering.

It will be realised that this illustrative covering has been selected for description by way of example and not of limitation of the invention.

In the drawing filed with the provisional specification: Figure 1 is a perspective view showing a portion of an article from which an externally screw-threaded member projects, with the illustrative protective covering, partly broken away, in position on the member; and Figure 2 is a view of the illustrative covering from its open end.

The ilustrative covering, 10, is a onepiece element of nylon 66 made by injection moulding. It comprises a tubular cylindrical sleeve portion 12 with two diametrically opposite longitudinal external grooves 14, V-shaped in cross section, running along the length of it to provide lines of weakness at which the portion is able to split on application of a suitable transverse force. The illustrative covering is closed at one end by an integral diaphragm 16 from which a flat tab 18 extends diametrically across the diaphragm, the plane of the tab 18 being at right angles to the plane in which the two grooves 14 lie. The illustrative covering is open at its other end.

Inside the sleeve portion 12 of the illustrative covering three uniformly disposed fins 20 extend lengthwise of the sleeve portion 16 and project from the wall of the sleeve portion towards a central area of the portion, each fin tapering in cross section towards the central area and being disposed generally tangentially to a notional cylinder of small radius coaxial with said portion.

The fins 20 are resilient enough to grip threads of a range of diameters; from Figures 1 and 2 it will be seen that their disposition is such as to facilitate removal of the covering from a right-hand threaded member by an unscrewing action if such should be desired. The fins 20 extend to the diaphragm 16, with which they are also integral, to facilitate moulding.

At its open end, the illustrative covering has an outwardly and downwardly (viewing Figure 1) flared skirt 22 which is adapted resiliently to bear upon the surface, 24, of an article from which a screw-threaded stud 26 projects.

The illustrative covering can easily and rapidly be pushed on to the stud 26 until the skirt 22 abuts the surface 24 and, the stud being gripped by the fins 20, will remain in position during painting or other subsequent manufacturing stages to which the article may be subjected. Having kept the threads of the stud clean during these stages, the illustrative covering can readily be removed by grasping the tab 18 between the thumb and forefinger and tugging it sideways in a direction at right angles to its plane, the sleeve portion 12 splitting at one of the lines of weakness afforded by the groove 14 as a consequence of its being forced by such tugging against the free end of the stud. The orientation of the tab 18 enables the application of force to assist such splitting by ensuring that one of the lines of weakness engages the end of the stud even though the grooves themselves may at such time be obscured by paint.

If, following the application of paint, the article passes through a stoving oven, the illustrative covering may split along one or both of its lines of weakness of its own accord under the influence of the heat.

The groove 14 of the illustrative covering extend the full length of the sleeve portion 12. If desired, they may be extended also over the skirt 22.

WHAT WE CLAIM IS: 1. A plastics protective covering adapted for application to an externally threaded member, to keep the thread clean during manufacturing operations, comprising a sleeve portion, closed at one end and open at the other, with a plurality of resilient inwardly projecting threadengaging portions adapted to hold the covering on a threaded member to which it is applied, the thread-engaging portions extending lengthwise of the sleeve portion and being symmetrically disposed around the inner wall of the sleeve portion generally tangentially to a notional cylinder of small radius coaxial with the sleeve portion.

2. A covering according to claim 1 having three thread-engaging portions as referred to.

3. A covering according to either one of claims 1 and 2 in which each threadengaging portion tapers in cross-section towards a central area of the sleeve portion.

4. A covering according to any one of the preceding claims which also comprises an outwardly flared, resilient, skirt to bear on the surface of an article from which a member to which the covering is to be applied projects.

5. A covering according to any one of the preceding claims comprising a tab at its closed end to facilitate its removal from a threaded member.

6. A covering according to any one of the preceding claims and having longitudinal lines of weakness at which the sleeve portion may split to facilitate removal from a threaded member.

7. A covering according to any one of the preceding claims made of nylon.

8. A plastics protective covering adapted for application to an externally threaded member and substantially as hereinbefore described with reference to the drawing filed with the provisional specification.

9. A method of protecting an externally screw-threaded member from paint or other coating material in the manufacture of an article by application thereto of a plastics protective covering according to any one of the preceding claims.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. extend the full length of the sleeve portion 12. If desired, they may be extended also over the skirt 22. WHAT WE CLAIM IS:

1. A plastics protective covering adapted for application to an externally threaded member, to keep the thread clean during manufacturing operations, comprising a sleeve portion, closed at one end and open at the other, with a plurality of resilient inwardly projecting threadengaging portions adapted to hold the covering on a threaded member to which it is applied, the thread-engaging portions extending lengthwise of the sleeve portion and being symmetrically disposed around the inner wall of the sleeve portion generally tangentially to a notional cylinder of small radius coaxial with the sleeve portion.

2. A covering according to claim 1 having three thread-engaging portions as referred to.

3. A covering according to either one of claims 1 and 2 in which each threadengaging portion tapers in cross-section towards a central area of the sleeve portion.

4. A covering according to any one of the preceding claims which also comprises an outwardly flared, resilient, skirt to bear on the surface of an article from which a member to which the covering is to be applied projects.

5. A covering according to any one of the preceding claims comprising a tab at its closed end to facilitate its removal from a threaded member.

6. A covering according to any one of the preceding claims and having longitudinal lines of weakness at which the sleeve portion may split to facilitate removal from a threaded member.

7. A covering according to any one of the preceding claims made of nylon.

8. A plastics protective covering adapted for application to an externally threaded member and substantially as hereinbefore described with reference to the drawing filed with the provisional specification.

9. A method of protecting an externally screw-threaded member from paint or other coating material in the manufacture of an article by application thereto of a plastics protective covering according to any one of the preceding claims.