US 2453742 A
Description (OCR text may contain errors)
Patented Nov. 16, 1948 TERMINAL ATTACHMENT FOB CRUTCHES AND THE LIKE Henry B. Bowen and Arthur M. Vineberg,
Montreal, Quebec, Canada 1945, Serial No. 584,462
" Application March 23 1 Claim.
This invention relates to ground-engaging terminal attachments for crutches, canes, ladders and the like and the object is to provide a termi-- nal attachment which gives exceptionally wide bearing area and is adapted to make fiat contact with the ground irrespective of the relative angular position of the crutch or other article to which it is applied.
More particularly, the invention comprises a ferrule connected to the central portion of a relatively large plate provided with a plurality of widely spaced ground-engaging lugs or feet depending from portions of the plate projecting a substantial distance laterally beyond the ferrule. The ferrule and plate are connected together by means permitting relative angular motion thereof so that the ground-engaging lugs of the plate will bear squarely on the ground when the crutch or other article to which the ferrule is applied is in a slanting position with reference to the ground.
Proceeding now to a more detailed description reference will be had to the accompanying drawings, wherein:
Fig. 1 is a plan view of one embodiment of our invention applied to a crutch which is shown in section.
Fig. 2 is a side elevational view, partly in section, of the assembly shown in Fig. 1.
Fig. 3 is a View similar to Fig. l but showing a slightly modified assembly.
Fig. 4 is a, side elevational view, partly in section, of the modified assembly shown in Fig. 3.
In the assembly shown in Figs. 1 and 2, 5 desi nates a ferrule fitted on the lower end of a crutch stick 6. The lower end of ferrule 5 is formed to provide a downwardly facing shoulder I surrounding an internally threaded neck extension 8 into which is screwed the shank 9 of a ball member Iii forming part of a ball and socket connection II provided between the ferrule and the central portion of a triangular plate I2. The corner portions of plate I2 project a substantial distance laterally beyond the ferrule and are provided with depending ground-engaging lugs I3 which may be of solid or hollow construction and may be formed integral with said plate or riveted or otherwise secured thereto. The plate I2 is provided with a central opening I4 through which shank 9 of ball I is passed'upwardly for screw threaded engagement with the neck 8 of ferrule 5. The wall of opening I4 is spherically curved to provide a ball seat against which the ball is held by a retaining plug I provided with a spherically curved ball-engaging seat I6. The plug I5 is screwed into a threaded socket I'I formed integral with the underside of plate I I. I
A coil spring I8 is interposed between ferrule 5 and plate I2 so that the upper end of the spring bears against shoulder I while the lower end of the spring is seated in a recess I9 provided in the upper surface of plate I2. As indicated by dotted lines in Fig. 2 each of the depending groundengaging lugs 13 of plate I2 may have a cushion-- ing cup 20 of rubber or similar cushioning material fitted thereon.
Spring I8 normally tends to maintain ferrule 5 perpendicular to the plane of the upper surface of plate I2 but is yieldable to permit the relative angular motion between the plate and the ferrule which is provided for by the ball and socket connection between these parts. As previously stated, the ball and socket connection permits the ground-engaging lugs of the plate to make and maintain fiat contact with the ground when the ferrule and the article to which it is attached are inclined with reference to the ground as indicated by dotted lines in Fig. 2.
The assembly shown in Figs. 3 and 4 is substantially the same as that previously described except that the spring I8 is replaced by a rubber ring 22 provided with a lower portion 23 of reduced diameter which is fitted in the recess I9 of plate I2. The rubber ring serves the same purpose as the previously mentioned spring I8.
In some cases, particularly where the attachment is applied to a ladder, the cushioning cups 20 shown in Fig. 2 may be omitted and the lugs provided, as indicated by dotted lines in Fig, 4, with conical points or spikes 25 adapted to dig into the ground.
An important feature of the invention resides in the fact that the pressure transmitted to plate I2 through the ball and socket connection has no tendency to overturn said plate even when the ferrule 5 is at the maximum permissible angle of inclination with respect to said plate. In this connection it will be noted that the lowest point of engagement between the ball I0 and its socket is located a substantial distance below the lowest surface of the plate.
Having thus described our invention it will be understood that various modifications may be resorted to Within the scope and spirit of the invention as defined by the appended claim. For example, the ferrule 5 and plate I2 may be connected together by any suitable means that will permit of the necessary relative angular motion thereof and the plate l2, instead of being triangular, may be of any other desired shape, the
principal consideration being that the groundengaging lugs of the plate are Widely spaced and formed integral with or attached to portions of the plate which project a substantial distance laterally beyond the ferrule. It will also be understood that the lugs l3 depending from plate I2 may vary in number or shape and may be formed integral with Or attached to the plate in any desired manner.
A terminal attachment of the character de-- scribed, comprising a plate provided with acentral vertical opening having its defining wall spherically curved to provide a ball seat, a socketforming wall extending downwardly from a portion of the plate encircling said opening, groundengaging members extending downwardly from portions of the plate located outwardly of said wall, a ball member fitted against said ball seat so that the major portion of the ball member is disposed below the upper surface of the plate with a substantial portion of the ball member lying below the bottom surface of the plate and within the socket formed by said wall, a ball-retaining plug removably secured in said socket and provided with an upwardly facing, spherically curved seat engaging the portion of the ball disposed within said socket, a ferrule havin its lower end secured to a part of the ball projecting above said plate and resilient biasing means arranged to act against said plate and said ferrule.
HENRY B. BOWEN. ARTHUR M. VINEBERG.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 332,684 Tuttle Dec. 15, 1885 765,984 Morris July 26, 1904 1,672g596 Zerk June- 5, 1946