Crutch

Feb. 28, 1956 l. a. wood 2,736,330

CRUTCH

Filed May 18, 1953

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ATTORNEY.

United States Patent Office

2,736,330

Patented Feb. 28, 195G

2,736,330

CRUTCH

Lorin A. Wood, Los Angeles, Calif.

Application May 18,1953, Serial No. 355,520 7 Claims. (CI. 135—49) ¹⁰

This invention relates to crutches used for walking ¹⁵aids by disabled persons and is directed to an efficient crutch construction that combines adjustability with structural simplicity.

Simplicity is achieved, in large part, by using a single columnar support member in the form of a tubular ²⁰shaft having an under-arm rest member at its upper end, and having a handgrip member extending laterally from an intermediate portion of the single support shaft. At first thought, it would seem that a thoroughly satisfactory crutch of this character could consist simply of ²⁵a straight shaft with a rest member positioned symmetrically on the upper end thereof and with the handgrip member extending perpendicularly from the straight shaft. In actual use, however, such a crutch is found to be awkward, uncomfortable, and noticeably fatiguing. 30 The handgrip is an especially distracting source of discomfort since it does not handle in a natural manner, and changing its height on the shaft or rotating it about the shaft to various trial positions does not eliminate the discomfort. 35

The invention solves the difficulty of awkwardness and discomfort by positioning the under-arm rest member in an off-center position on the upper end of the shaft with an intermediate portion of the handgrip positioned to be intersected by a straight line extending 40 from the center of the upper rest member to the bottom end of the shaft. Such a straight line may be termed the support axis of the crutch.

The intermediate portion of the handgrip that is on this support axis is the portion on which the heel of the 45 user’s hand rests to transmit weight to the crutch. Thus, three support lines are placed in a straight line, namely: the upper support point at the center of application of weight to the under-arm rest member; the intermediate support point where weight is transmitted to the hand- 50 grip; and the bottom support point where the lower end of the crutch transmits the total weight to the floor or ground. With such alignment of the support points, and especially with the handgrip extending substantially perpendicular to the support axis, there is a desirable 55 naturalness in the manner in which the crutch responds to manual manipulation there being no troublesome tendency for the crutch to twist in response to the weight applied to the handgrip.

In practice, it has been found that the desired result 60 may be attained with the major portion of the shaft substantially straight, with the axis of this major portion of the shaft at an angle of approximately 3 degrees from the support axis and with the handgrip substantially normal to the support axis, i. e., inclined down- 65 ward about 3% from a position perpendicular to the axis of the straight portion of the shaft. With these angular relations, the central or intermediate portion of the shaft is offset from the support axis and, of course, the upper rest member is in offset position relative to 70 the axis of the intermediate and lower portions of the shaft. The whole shaft may be straight with the upper rest mounted thereon in such manner as to extend to one side thereof or the upper end of the shaft may be bent or curved to hold the upper rest member in the desired offset position.

With reference to adjustability, two adjustments are required, namely, adjustment in overall length and adjustment in the elevation of the handgrip on the shaft. In the preferred practice of the invention both kinds of adjustment are achieved by means including adjustment screws that are concealed and yet readily accessible. Thus the only tool required to make a change in adjustment is a screw driver.

The various features and advantages of the invention will be apparent in the following detailed description considered with the accompanying drawings:

In the drawings, which are to be regarded as merely illustrative:

Figure 1 is a side elevation of a selected embodiment of the invention;

Figure 2 is a section taken on the broken line 2—2 of Figure 1;

Figure 3 is a section taken along the line 3—3 of Figure 1;

Figure 4 is a fragmentary view partly in section and partly in side elevation showing the construction at the juncture between the handgrip and the shaft;

Figure 5 is a sectional view of the bottom end of the crutch; and

Figure 6 is a side elevation of a second embodiment of the invention.

The principal parts of the first form of the invention shown in Figures 1 and 5 include: a single support shaft 10; a rest member 11 on the upper end of the shaft for positioning under the arm crotch of the user; a lateral handgrip 12 positioned at an intermediate point on the shaft; and the usual rubber member 13 that forms a cushioning tip at the lower end of the crutch for non-slipping contact with a support surface.

The rest member 11 is shaped with an upper arcuate support surface 17 to receive the under-arm weight of the user with the center of the weight or downwardly applied pressure at the point indicated by the arrow 18. The handgrip 12 also bears a portion of the user’s weight which is applied by the heel of the user’s band in the region of the root of the thumb, the center of this application of downward pressure on the handgrip being indicated by the second arrow 19. In accord with the invention, these two centers of pressure application 18 and 19 are on a straight-line support axis 20 which is indicated by the dotted line in Figure 1 and which extends to the center of the bottom end of the crutch.

Since the pressure center 19 on the handgrip 12 is necessarily spaced away from the juncture of the handgrip with the shaft 10, the shaft 10 in the region of the handgrip is correspondingly offset from the support axis 20. In this particular embodiment of the invention, the major portion of the shaft 10 extending upward from the lower end of the shaft to a point above the handgrip 12 is substantially straight and the required offset of the shaft from the pressure point 19 on the handle 12 is achieved by inclining this major straight portion of the shaft away from the support axis 20 by an angle of approximately 3 degrees. Preferably the bottom face 21 of the rubber member 13 is correspondingly inclined by approximately 3 degrees from the axis 22 of the shaft to make the bottom face substantially perpendicular to the support axis 20.

The upper rest member 11 may be of any suitable construction and may be mounted on the upper end of the shaft 10 in any suitable manner that offsets the upper pressure point 18 from the axis of the major por2,736,330 the main tube 10 for the purpose of changing the effective length of the crutch.

The utility of the crutch and the manner in which it may be adjusted to meet the needs of individual users may be readily understood from the foregoing description. The screw 36 inside the handgrip 12 is concealed but nevertheless is conveniently accessible for rotation by an ordinary screw driver, so that the screw may be loosened for adjustment of the height of the grip member without requiring any special tools and without requiring any special skill. The screw 51 at the bottom end of the crutch is also concealed but -at the same time readily accessible for rotation by a screw driver so that the tubular core 48 may be withdrawn from the lower end of the main tube 10 to permit the replacement of the supplemental tube 45 by a second supplemental tube of different length thereby to vary the effective length of the crutch.

The second embodiment of the invention shown in Figure 6 is largely identical with the first described embodiment of the invention, as indicated by the use of corresponding numerals to designate corresponding parts. In this particular construction, the tubular shaft 10α is substantially straight throughout its length, being inclined approximately 3 degrees from the support axis 20 as. heretofore described. The rest member 55 on the upper end of the shaft 10α may be of any suitable construction to place the pressure point 18 or center of weight application in the offset relation with respect to the axis, of 30 shaft 10α to conform to the support axis 20.

In the illustrated construction, the rest member 55, which is formed with a triangular aperture 56, is provided with a cylindrical socket 57 to receive the upper end of the tubular shaft 10α. Suitable cross pins or screws 60 35 in the body of the rest member 55 may extend through corresponding apertures in the tubular shaft 10α for the purpose of effectively interlocking the rest member 55 with the shaft.

In this embodiment of the invention the hand grip is mounted on the intermediate portion of the shaft 10α in exactly the same manner as is the hand grip mounted in the earlier described embodiment of the invention. In this form of the hand grip the rubber sleeve is molded with a laterally extending protuberance 38α which acts to 45 prevent movement of the hand longitudinally of the hand grip in a direction away from the tubular shaft forming the body of the crutch. This hand grip formation is of particular importance for patients who do not have full icxuugixp -- vxx- control of their hands and who are not able to tightly be loosened when 50 clasp the hand grip during the use of the crutch.

Although the now preferred embodiments of the present invention have been shown and described herein, it is to be understood that the invention is not to be limited thereto, for it is susceptible to changes in form and deΓ 55 tail within the scope of the appended claims.