US3269400A

US3269400A - Crutch pad

Info

Publication number: US3269400A
Application number: US261799A
Authority: US
Inventors: Alfred A Smith; Howard C Lien
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-02-28
Filing date: 1963-02-28
Publication date: 1966-08-30
Anticipated expiration: 1983-08-30

Description

Aug. 3U, 11%@ A. A. SMITH ETAL CRUTCH PAD Filed Feb. 28, 1963 ,MF/2N WML E m5, .N Abg D f W RM FW L A# 3,269,460 Patented August 30, 1963 3,269,400 CRUTCH PAD Alfred A. Smith, 8277 Lankershim Blvd., North Hollywood, Calif., and Howard C. Lien, Los Angeles, Calif.; said Howard C. Lien assignor to said Alfred A. Smith Filed Feb. 28, 1963, Ser. No. 261,799 1 Claim. (Cl. 13S-52) This invention relates to a new and improved crutch pad.

The present invention relates particularly to crutch pads which are formed of an elastomer, commonly sponge rubber or the like, and which are provided with a hollow interior and an elongated downwardly facing slightly smaller opening which extends along the bottom of the pad. In use, the pad is stretched along the opening to fit the crutch armpiece.

The areas of the crutch which are along the edges of this opening and particularly the areas at the opposite ends of the opening are subjected to constant strain and tension while the paid is in place on the crutch, and failure of the crutch pad customarily occurs in these areas. Such failures usually occur due to the fact that the elastomer tends to oxidize over a period of time and the material deteriorates due to the combination of age and constant strain.

It is accordingly an object of the present invention to provide a new and improved crutch pad in which the crutch receiving opening, and particularly the ends thereof, is strengthened to prevent such failures and deterioration, to improve the gripping ability of the pad with respect to the armpiece, and to lengthen the usable life of the pad.

In essence, the invention contemplates reinforcing the crutch receiving opening, and particularly the ends thereof, with a band or other suitable piece of material having resiliency but greater tensile strength than the material used to form the body of the pad. The reinforcing material may also be less susceptible to oxidation. A preferred embodiment of the invention particularly contemplates the use in a pad formed of sponge rubber or the like of a band of mechanical rubber which is molded or otherwise permanently bonded to the interior of the pad adjacent to and circumscribing the crutch receiving opening or a portion or portions thereof.

The preferred method of forming the pad contemplated by the invention comprises mounting such a band or other piece of mechanical rubber or the like on the mandrel or male portion of the mold around which the crutch pad is formed and then molding the body portion of the pad around the band so that the band and body portion of the pad are bonded together during the molding of the pad.

It is accordingly among the objects of the invention to provide a crutch pad having all of the advantages and benefits of the structure and method set forth above and described in greater detail hereafter in this specification. The invention also comprises such other objects, advantages and capabilities as will later more fully appear and which are inherently possessed by the invention.

While there are shown in the accompanying drawing preferred embodiments of the invention, it should be understood that the same are susceptible of modification and change without departing from the spirit of the invention.

Referring to the drawings,

FIG. l is an exploded isometric view of the crutch pad and crutch armpiece, with the pad partly broken away and shown in section;

'FIG. 2 is an elongated sectional View ofthe crutch pad;

FIG. 3 is a transverse sectional View of the same, taken on line 3-3 of FIG. 2;

FIG. 4 is a longitudinal sectional view of the mold in open position with the blank disposed within the female mold and the band mounted around the mandrel of the male mold;

FIG. 5 is a transverse sectional view of the mold in closed position, with the blank and band disposed therein;

FIG. 6 is a top plan view of the blank;

FIG. 7 is a sectional view of the blank taken on line 7-7 of FIG. 6.

Referring first to FIGS. l-7 of the drawings, a crutch pad of the type with which the invention is adapted to be used customarily comprises a single elongated piece of a somewhat soft or resilient cushion-like body portion 10, which may be formed of any suitable cellular or non-cellular elastomer including, but not limiting to, natural and synthetic rubbers and foams, vinyl, polyurethane or any other material having properties comparable thereto. The body portion 10 has a closed upper surface, a hollow interior 17 and a lower surface having an elongated longitudinally directed downwardly facing bottom opening for removably mounting the pad on the armpiece 12 of a crutch. The pads are customarily formed in a mold having a male part or mandrel 13 and a. complementarily formed female mold 14.

If the body portion 10 is formed of sponge rubber or the like, a blank 15 of raw compound is placed within the female mold 14. The mold is then closed with the blank 15 inside. The mold is placed between a pair of heated plates and heat of approximately 300 F. is applied for approximately twenty minutes to cause a chemical reaction within the raw compound which causes it first to expand and then to be vulcanized or cured. Pressure is maintained during the heating operation in order to prevent separation of the mold parts.

A preferred embodiment of the invention contemplates placing around the bottom of the mandrel 13:` prior to the molding operation an elongated endless loop or band 16, which may be formed of suitably compounded mechanical rubber or any other suitable elastomer which has greater tensile strength and preferably higher resistance to wearing and aging than the material forming the body portion 10. The compound used to form the band 16 preferably has a comparatively high heat resistance so that the band 16 will suitably withstand the heat required to form and cure the sponge rubber forming the body portion 10. The compound used to form the band 16 should also have a fairly low modulus of elasticity and be sufficiently elastic to retain itself in place on the mandrel 13. The band 16 should not be too strong, or it will tend to pucker or draw up the opening after the pad is formed.

The mandrel 13 should preferably have a substantially fiat or straight bottom edge so that the band 16 extends and maintains itself so that the bottom edge of the band 16 extends and is maintained in a straight line directly :adjacent to the base of the mandrel. The body portion 10 of the pad is then formed4 in the manner described above, and the band 16 is bonded to the body portion 10 of the pad during and through the molding process, so that the band 16 becomes `an integral part of the finished pad.

In the finished pad, the band 16 extends circumferentially `around and adjacent to the lower surface of the pad which forms the inner edge of the crutch armpiece receiving opening and thus reinforces the portions of the pad which are most subject tofailure due to tension acting either alone or in combination with deterioration of the elastomer due to aging and oxidation. Since these failures loccur principally around the opening, the band 16 provides at such points the strengthening necessary to improve the grip of the pad upon the armpiece 12 and to prolong substantially the life of the pad.

Since the band 16 has greater tensile strength than the body portion 10, it provides a somewhat better grip on the crutch, and the strain :on the pad in use is absorbed primarily by the band 16 rather than by the softer body portion 10. The result is that both the gripping and lasting qualities of the pad are improved without simultaneously losing or altering the desirable cushioning qualities of the body portion 10.

The band 16 may have any suitable thickness. The exposed outer surface of `the band 16 may be washed with water and/or a suitable solvent compatible with the elastomer forming the band 16 prior to mounting the band 16 on the mandrel 13 in order to increase and facilitate bonding of the band 16 to the body portion 10. A suitable adhesive lor bond improving composition may also be used as desired for the same purpose.

The width and shape of the band 16 may be varied las desired and it may take 'the form of a sheath which completely en-closes the mandrel 13, in which case it lines the entire interior 17 of the pad. It is also within the contemplation of the invention to use 4one or more smaller bands Ior sheaths which extend only around a selected portion or portions of the mandrel 13, such as the ends.

The band 16 may be formed of completely cured or partially cured elastomeric material.v If the material forming the band is only partially cured, the molding operation completes the cure and the band 16 becomes bonded to the body portion 10 because 'they are both to some extent cured simultaneously.

Instead of molding the band 16 into the pad as described above, the band 16 may be mounted in the pad after the body portion 10 has been formed through the use of suitable adhesive compositions, either with or without the use of heat and/or pressure to :facilitate and improve the bonding of the pad 16 to the body portion 10.

The band 16 or the equivalent thereof may also be :applied to the body portion 10 through the use of a suitable liquid or semi-liquid coating which contains or has the properties of an elastomer. Such coating is applied `around all or a selected portion or portions of the opening and when dried imparts the desired properties of increased strength and age resistance to the area adjacent to the opening.

The edge of the band 16 may be formed flush with the bott :im edge of the pad 10, or it may be formed so that it =p1 otrudes slightly. This protrusion is accomplished by providing a small groove 18, which surrounds the base of the mandrel 13 and into which the band 16 ts. The advantage of this structure is that if the sponge rubber material spills or flashes over the edge of the band 16, the flashing or excess material can easily be removed by bung the protruding portion of the band 16.

We claim:

A crutch pad having a cushion-like body portion having an upper surface and lower surface, said body portion having a hollow interior and `a crutch receiving opening extending into said interior from said lower surface, said body portion being formed of molded elastomeric material, and an elongated band of elastomeric material having greater tensile strength and resistance to aging than said body portion, said band being bonded to said body portion, said band extending circumferentially around the entire periphery of said crutch receiving opening and being positioned contiguous to said lower surface to reinforce said crutch receiving opening.

References Cited by the Examiner UNITED STATES PATENTS HARRISON R. MOSELEY, Primary Examiner. BENJAMIN BENDETT, Examiner. L. I. SANTISI, Assistant Examiner.