US1055111A - Crutch-tip. - Google Patents

Description

W. B. WILGOX.

ORUTOH TIP.

APPLIOATI'ON FILED JULY 1, 1912.

1,'055,1 1 1. Patented Mar. 4, 1913.

WITNESSES: INVENTOR.

-15 which, when pressure is exerted on the WILLIAM B..'WILCOX, OF YPSILANTI, MICHIGAN.

CRUTCH-TIIP.

Specification of Letters Patent.

Patented Mar. 4, 1 913.

Application filed July 1, 1912. Serial No. 706,890.

7 '0 all ur/mm, it may concern:

Be it known that I, WILLIAM B. Wincox, a citizen of the United States, residing at Ypsilanti, in the county of Wayne and State of Michigan, have invented certain new and useful Improvements in Crutch- Tips, of which the following is a specification.

This invention relates to tips for crutches and the like, and it has for one of its objects the provision of a device of this character which will not slip even under loads which are placed upon the staff under extremely sidewise conditions.

The invention has, furthermore, for its object the provision of a tip having a bearing surface of considerable area and which, due to its particular construction, willlast a long time.

Further objects of the invention will hereinafter appear and be particularly defined in the claims.

The invention has been clearly illustrated in the accompanying drawings, in which, similar characters denote similar parts, and in which I Figure 1 is a central vertical section through a tip embodying my invention, and Fig. 2 illustrates the tip exposed toan extreme lateral pressure or load.

Briefly stated, my improved tip is designed to overcome two distinct and great faults which are prevalent in, the crutch tips heretofore used, to wit :-first-: the short life which is incident to the wear to which these, the tips are usually exposed, and second: to obviate the uncertainty of footing and holding qualities thus far found in devices of this character.

Referring now to the drawings, my improved tip comprises a thimble 1O preferably made of rubber and having internal corrugations, 11 adapted to come into frictional contact with the foot-end of the crutch C, the lower end of which is rounded as .clearly shown in Fig. 2. The lower portion of the recess of the thimble 10 is concaved, as shown at 12, so that the end of the crutch may find a firm footing therein, and be adapted for a rocking movement in the same. The underside of the base portion 13 of the thimble isprovided with a recess or chamber 14 leaving a resilient web crutch, will slightly yield, andtend at the same time to draw the walls'of the thimble,

and especially the portions 10 thereof, into close contact with the end of the crutchstick, so that in this manner the latter and the thimble will become more firmly attached to each other in the same ratio as the pressure upon the crutch-stick increases.

It will be noted that the lower face 13 of the base is flat, in contradistinction to the spherical or convex form usually found in devices of this character. This construction enables the tip, as a whole, to find a substantial surface footing, when in use, and without any tendency of slipping. In fact the base of the tip remains practically stationary even'if the crutch stick is swung around its support, which in the present instance has its axis practically in one point, indicated by a in Fi 2 in which the crutchstick C is illustrate in an extremely-tilted position. In this instance the line of direct side thrust is indicated by t, while the actual load line, gravitatively, is that indicated by Z. Taking into consideration the parallelogram of forces evolved from the lines of thrust and load, it is found that the resultant R intersects the base line at b and that the angle formed with the base line is more than steep enough to permit any tendency of slipping to materialize. Furthermore it will be noted that this resultant R passes in this extreme case through a solid body of rubber, so that consequently the greatest resistance to the side thrust is thus offered to '90 the crutch-stick, and the latter therefore obtains apractically solid foundation. It is also evident that the more perpendicular the position of the resultant R becomes relative to the base line, the less of such firm resistance is required, and for this reason the central chamber or recess 14 is small enough as to permit the web 15 to yield slightly,

and therefore afford more or less resiliency to the foot support for the crutch-stick, a feature which in itself is important, and of great relief and comfort to the user. Furthermore, the provision of this central aperture will permit, especially on rainy days, the water on the side-walks tobe squeezed out from under the annular rim or base surface. of the tip, far more readily than it would if the base were solid in its entirety.

Experience with the resent crutch tip has fully shown that the hold which the tip akes on the side-walk or floor is very great, this fact being due to a great extent to the reduction of the base-web and the chamber disposed below the same, and also to the particular convex formation of the end of the crutch-stick which isseated in the concave recess of the tip. 1

' Changes may be made in the particular construction of the device, and especially in the stick-holding portion thereof, without departing from the spirit of the invention,

I claim 1. .A crutch tip having a concave seat for 2 crutch, and also having a flat base sur-,

ace..

2. A crutch tip having a concave seat for a crutch, and also having a fiat base surface, and. a chamber in the lower surface of the base.

3. A crutch tip having a concave seat for a crutch, and also having a flat base surface, and having a stick-supporting web of less thickness than that of the tip base.

In testimony whereof I afiix my signature in presence of two witnesses.

WILLIAM B. WILCOX.

Witnesses:

H. D. MACDONALD, F. M. WARDLE.

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