US 2590648 A
Description (OCR text may contain errors)
March 25, 1952 c PlTZ 2,590,648
SLOTTED SOLE SANDAL- Filed Jan. 12, 1949 2 SHEETS-SHEET l A NVENTOR 32 CARL A. Prrz 17 12150 5 BYQ 5 WW ATTORNEY March 25, 1952 Filed Jan. 12, 1949 C. A. PITZ SLOTTED SOLE SANDAL 2 SHEETSSHEET 2 INVENTOR ATTORNEY Patented Mar. 25, 1952 SLOTTED SOLE SANDAL Carl A. Pitz, New Holstein, Wis., assignor, by mesne assignments, to A. L. Langenfeld, Inc., New Holstein, Wis., a corporation of Wisconsin Application January 12, 1949, Serial No. 70,441
2 Claims. (Cl. 36-11'.5)
This invention relates to sandals and particularly slotted sole sandals having a hinged sole retained on the foot by means of straps.
' An object of this invention is' to provide a sandal having a hinged sole adapted to flex with the foot and which is comfortable and durable.
Another object is to provide a sandal having a hinged sole which may be manufactured at low cost.
' Another object is to provide a sandal having a sole hinged to pivot freely without pinching or irritating the foot.
A further object is to provide a sandal having straps which comfortably retain the sandal on the foot.
Still a further object is to utilize straps for retaining a sandal on the foot without cuttin the foot with the strap edge.
Other objects and advantages will be pointed out in, or be apparent from, the specification and claims, as will obvious modifications of the single embodiment shown in the drawings, in which:
Fig. 1 is a top view of a sandal for the right foot;
Fig. 2 is a side elevation of the sandal as worn on the foot shown in dotted lines;
Fig. 3 is a top view of the sandal with the straps removed; "Y'Fig. 4 is a side elevation of the sandal wit the straps removed;
,' Fig. 5 is a bottom view of the sandal; and
' I 'Fig. 6 is a vertical section through the hinge on line 6-B in Fig. 4.
Referring to the drawings in detail, Fig. 1
shows the top of a completed sandal with the strains in the position they occupy when the sandal is worn on the foot as shown in dotted lines in Fig. 2. The sole ll) of the sandal is preferably constructed of wood having its grain running alongits'longitudinal axis (toe to heel) for reasons which will appear hereinafter. The sole con sists of three pieces hinged together to flex with the foot. The most forward portion l2 underlies the toes with the ball of the foot resting on the center section l4 and the remainder of the foot on the heel portion l6. As the length of the sole is varied for different foot sizes, the proportions of the sections must be maintained in order to avoid irritation by the hinges and to insure comfort.
The hinge construction between the three sole pieces is best shown in Figs. 3 through 6. The center section 14 is provided with vertical transverse walls l8, 20 from which a plurality of spaced hinge lugs 22, 24, respectively, project. Lugs 22 interfit with spaced lugs 26 formed in the heel portion I6. It will be noted that the hinge lugs have curved faces to permit free movement of the parts with respect to each other as they rotate about hinge pin 28 which passes through the interfitting lugs and terminates in the heavier or wider lugs 26 adjacent the inner and outer edges of the shank. The hinge lugs 26 on the heel portion I6 are undercut at 36 for reasons which will appear hereinafter.
Hinge lugs 24 on the forward wall of center section [4 similarly interfit with spaced hinge lugs 32, undercut at 38, on the toe portion l2. These interfitting lugs are adapted to pivot on hinge pin 34 which terminates in the wide lugs 35 on the toe section adjacent the inner and outer edges of the shank. Further reference to Fig. 6 will also show that pin 34 may be retained in position in the interfitting lugs by plug 36 to obtain a matching finish on the exterior of the sandal while utilizing a metal pin.
As the sole of the sandal flexes there is complete freedom of movement of the component parts to insure the utmost in comfort. The undercutting of the hinge lugs 26,- 32 on the heel and toe portions l6, l2 at 36 and 3B prevents the lugs from contacting the surface under the sandal. Thus there is no frictional resistance to flexing the sandal as a result of the hinge lugs rubbing over the surface under foot. While the hinge lugs on the center section l4 are shown as being slightly undercut, this is merely a manufacturing expedient. These lugs cannot scrape the undersurface since flexure of the sandal raises the center section from the surface as or before the center section flexes with respect to the toe portion.
While frictional resistance due to the hinge lugs scraping on the undersurface has thus been avoided, it would appear at first blush that the relatively movable parts of the sole would tend to pinch the foot. It has been found, however, that positioning the hinge pin above the medial plane of the sole minimizes such pinching by reducing relative movement of the upper sole surfaces for a given degree of rotation of the parts. This is shown in Fig. 6 where the distance a from the bottom of the sole to the centerline of the pin is greater than the distance 1) from the centerline to the top of the sole.
Another feature resulting in complete foot comfort is the manner in which the forward hinge lugs 24 on the center section l4 are offset toward the inner edge of the sole with respect to the lugs 22 on the rear face of the center section. Moving the interfitting lugs 24 toward the inner edge of the sole in this manner reduces ir- 3 ritation of the muscle running from the big toe to the ball of the foot and additionally serves to conform the shape of the hinge portion of the sole between the toe section l2 and the center section 14 to the shape of the sole.
Care must be taken to leave ample material on the toe and heel portions adjacent the inner and outer edges of the sole to receive the ends of the corresponding hinge pin. As pointed out above, the grain of the Wood runs generally from heel to toe, and if the ends of the hinge pin were not anchored in the heavy material adjacent the inner and outer edges of the heel and toe portions, the pin would tear through the hinge lugs. Running the grain crosswise would not eliminate this trouble since the hinge lugs would then snap 01f at th roots. The center section l4, however, need not be provided with such Wide lugs. since the stress acts at a slight angle to the grain and the pin neither tears out nor shears the lugs. Thus this structure completely eliminates any tendency'for'the hinge pins to tear out of or to shear the hinge lugs. The resultant straight vertical transverse walls on the center section permit simplified manufactureof the center section and material cost reductions.
The sandal is retained on the foot by means of two straps, one fitting'over the heel and'angle and the other fitting over the-forward portion of the. foot. as shown in Figs. 1 and 2. The heel portion l6 is'provided-with a rearwardly inclined transverse. slot 40-through which strap 42 passes. One end of the strap passes through a pair of slots 44, 46 on the strap to frictional'ly'retain a loop in the lower part of the strap. This permits the strap to be adjusted" to the particular heel so that the cross-over point generally denoted. 48 lies over the. heelxas' shown. The endsof the" strap are then brought around the angle and buckled to firmly hold the heel'to-the sole. Thus strap 42 generally assumes afigure 8' shape with the lower loopv passing through slot 40. and fitting over theheel and the upper 100p encircling, the ankle. The. rearwardly inclined slot 40' causes the lower loop of" strap 42 to form a pocket receiving and lying flat against the. heel, thus avoiding'any cutting of the heel.
Theforward part of the foot is retained'on' the sandal by means of strap 50; This strap passes through forwardly inclined transverse slots' 52;
54,56 in the heel, center, and't'oe portions of the sole., The forward, inclination of the slots is particularly advantageous in the case of'slot's 54;v 56 in the center and toe portionswhere they slightly twist the strap so that the strap portions adjacent the sole will be substantially parallel to the edge of the. sole andjcont'act' with the foot over thefull strap width. If these slots were horizontal, the rear edge of the strap would liecloser to the sole of the foot than would theforward edge, resulting incontact with the foot localized at the said edge of the'strap. Thusthe provision of forwardly inclined slots generally shapes apocket com- 4 fortably receiving the foot and conforming to the foot. It will be noted that the buckle on strap permits adjustment of the total length of the strap. This results in the strap adjusting itself to the individual foot since the strap is free to slide in the slots 52, 46.
Although but one embodiment of the present invention has been illustrated and described, it will be apparent to those skiled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.
1. Asandal having a sole having toe and ball portions the upper and lower faces of which are generally: parallel, a plurality of transverse forwardly and downwardly inclined slots through said sole in the toe and. ball portions thereof, and a strap passin through said slots and diagonally' over the'foot, theinclination of'said' slots serving to twist the strap to-lie flat against the foot.
2. A sandal having a sole including; toe; ball, shank and heel portionsysaid heel portion being thicker than the toe and ball portions, and the upperand lower'faces ofthe toe, and ball portions being generally parallel, the upper face of the shank portion sloping upwardly and rearwardly, a plurality of transverse slots in said toe and ball portions inclined downwardly. and forwardly; a transverse slot in said shank portion inclined forwardly and downwardly, and a strap; passing through said slots and diagonally over the foot, the ends of the strap" being adjustably'interconnected to form a pocket receiving the toe, balliand instep portion. of the foot: and the inclinationof said slots serving to twist the strap tolie fiat against said portionsof'thefoot.
CARL A. PITZ.
REFERENCES CITED The following references are of record in-v the file of this patent:
UNITED STATES PATENTS Number Name Date 1,341,498 Demarmels May 25;.1920 2,126,077 Youngberg 'Aug. 9; 1938 2,126,094 Daniels Augz-9; 1938 2,343,701 Pickens ar. 7,. 1944 2,466,580 Dalbey -fApr. 5;. 1949 FOREIGN I PATENTS Number Country: Date- 6,757 Great Britain May 20, 1886' 686,325 France Apr;v 8, 1930 745,045 France Feb: 7, 1933 874,012 France" Apr. 13,1942 876,666 France Aug. 10, 1942 879,963 Austria Feb..10', 1920 880,213" France Dec: 18; 1942