Adjustable Crampons

Abstract

An adjustable crampon with a frame which is articulated for width adjustment and has extensible rear frame members for length adjustment, and is made rigid after being fitted to a given boot.

Description

BACKGROUND OF THE INVENTION

The present invention relates to adjustable crampons applied to climbing boots for alpinism, ice climbing, walking on icy surfaces, and other mountaineering pursuits, and more particularly, relates to rigid type crampons as distinguished from the hinged type. In the rigid type the full length of the crampon is a rigid frame, whereas in the hinged type, shown for example in U.S. Pat. No. 3,685,173, the portions of the crampon beneath the boot heel is free to flex relative to the portion beneath the sole.

Some rigid type crampons have been made adjustable in the past both in length and width to accommodate a range of boot sizes and sole shapes, but the adjustment system has had the drawback of not being such as to make it possible to adjust for the full expanse of boot widths in such a manner as to locate the depending point elements substantially as far out laterally as the extent of the boot sole, particularly in the region of the widest part of the boot. Such a point location is vital so that the climber, especially when having to make footing on a narrow ledge or step, can locate crampon points close to the inner side of the ledge without interference by way of engagement of the side of the boot sole with the adjoining rock or ice wall.

SUMMARY OF THE INVENTION

An important object of the present invention is to eliminate the above-mentioned drawback in the rigid crampons of the known adjustable types.

Another object is that of providing an adjustable crampon that is sturdy and safe to use and yet can be economically produced.

These and further objects which will better appear from the following description are attained by, in effect, making the frame of the crampon a closed four-bar articulated linkage that is adjusted in width by articulating the frame and is locked by a central cross-link assembly which is adjustable in effective length. The two rear bars of the linkage are adjustable in length to adjust the length of the crampon frame and the cross-link assembly can be positioned at various points along the rear bars to properly locate central strap posts fixed at the ends of the assembly. These strap posts complement pairs of front and rear strap posts upstanding from the four-bar linkage which also has the crampon points integral therewith.

BRIEF DESCRIPTION OF THE DRAWING

Further characteristics and advantages will appear from the following detailed description of a crampon embodying the invention and illustrated by way of example in the accompanying drawing in which:

FIG. 1 is a bottom perspective view of the crampon in operative position in a boot shown in phantom;

FIG. 2 is a top plan view of the crampon;

FIG. 3 is a longitudinal vertical sectional view taken along the line 3--3 of FIG. 2;

FIG. 4 is a detail fragmentary bottom plan view of one of the center articulations as indicated by line 4--4 in FIG. 3;

FIG. 5 is a transverse cross-sectional view to the rear taken along the line 5--5 of FIG. 2; and

FIG. 6 is a transverse cross-sectional view to the front taken along the line 6--6 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings, it is seen that for purposes of example the invention has been shown applied to a 12 point crampon 17 having 10 vertical point elements and two forwardly projecting front point elements 18-19 shaped downwardly from the horizontal about 20.degree. . The vertical points comprise a pair 20-21 at the rear, a pair 22--23 near the front of the heel location, a pair 24-25 at the front of the instep location, a pair 26-27 at the wide portion of the foot, and a pair 28-29 near the front.

The crampon is provided with three pairs of strap posts 30-31, 32-33 and 34-35 at the rear, center and front, respectively. Each of these has a slot 36 for receiving a lace style crampon strapping for holding the crampon onto a boot in the conventional manner. It will be noted that the rear strap posts 30-31 diverge in the forward direction to serve as a rear stop for the boot heel and that the front strap posts converge in the forward direction.

The point elements are integral extensions of rear, center and front pairs of longitudinal frame members 38-39, 40-41 and 42-43, respectively, which are interconnected by a pivot screw 44 at the rear, a two-piece adjustable cross-link 46-47 at the center, and a pivot screw 48 at the front. Also integral with the rear members 38-39 and front members 42-43 are the rear strap posts 30-31 and front strap posts 34-35, respectively. The center strap posts 32-33 upstand integrally fron the outer ends of the adjustable center cross-links 46-47. It is preferred that frame members and cross-links of the crampon be formed from high strength chrome molybdenum steel.

For length adjustment of the crampon frame the rear frame members 38-39 are each provided with a longitudinal row of equally spaced holes 50 from a straight section forwardly of the points 22-23, and the center frame members 40-41 are perforated along most of their length with holes 51 spaced apart in like manner to the holes 50. Two pairs of screws 52-53 and 54-55 passing through mating of the holes 50, 51 are used to rigidly clamp the center and rear frame members together in adjusted position with the front portion of the rear members 38-39 overlapping a rear portion of the center members 40-41.

Width adjustment of the crampon at the front and back is accomplished by respective sets of matching holes 56 and 57 formed in lateral front extensions 42a- 43a and rear extensions 38a- 39a. So that both sides of the crampon will be at the same sole level, the lateral extensions 38a and 42a are offset downwardly to extend beneath the extensions 39a and 43a, respectively, as shown in FIGS. 5 and 6. Similarly, the rear end portions of the front members 42-43 are offset downwardly, as indicated at 43a for member 43 in FIG. 3, to extend beneath the forward end portions of the center members 40-41 to receive therethrough pivot screws 58-59 and set screws 60-61 threaded into overlying holes in the center members. The set screws 60-61 pass through lateral slots 62-63 as best seen in FIG. 4. It will be noted that the center member 40 may be straight throughout its length whereas the other center member 41 bends outwardly forwardly of the point element 25 so as to complement the curved shape of the rear portion of the respective front member 43.

The center cross-links 46-47 overlap, the cross-link 46 being downwardly offset at 46a to pass beneath the cross-link 47. The overlapped portions have respective rows of holes 62-63 along their length for receiving a center adjusting screw 64 and side adjusting screws 66-67, the latter two passing through selected of the holes 51 in the center members 40-41. There is a differential spacing between the two sets of holes 62-63 so that small endwise adjustments of the center cross-links 46-47 will always place two of these holes in registration to receive the screw 64.

Of the afore-mentioned complementing sets of holes in the frame members and center cross-links, the upper sets are tapped from beneath and the lower sets are clearance holes. The screws are threaded into their respective holes from the underside to leave flat top surfaces. It is preferred that the screws be of the allen head type.

To fit the crampon to a given boot, the width at the front and rear are first set by adjusting the screws 48 and 44 in the respective holes 56-57 so that the front points 18-19 project the desired amount forwardly of the toe of the boot when the boot is jammed against the front posts 34-35, and so that the rear posts 30-31 bear against the rear rounded corner portions of the heel. Normally, the front adjustment is made after the center sections 40-41 have been connected to the front sections by the screws 58 through 61, but that is optional. Howbeit, usually the crampon is next adjusted for length and the locking screws 52 through 55 set in place to rigidly secure the center and rear members together.

Then, with the front and rear screws 48 and 44, and the central screws 58 through 61, all loosened, the crampon frame is articulated as a four bar closed linkage such as to locate the points 26-27 beneath the outer edge of the wide part of the boot sole. Then the fore-going six screws are tightened. To securely lock this adjustment the cross-links 46-47 are then positioned with the center strap posts 32-33 at the proper instep location and the screws 64, 66 and 67 set and tightened in place. With all of the screws tightened the crampon frame is not only locked against articulating but is rigid in the vertical direction. This rigidity is assisted by having central longitudinal ribs 68 formed at the underside of the front members 42-43.

Summarizing, it can be seen that in its assembled form the crampon frame comprises a closed four-bar linkage in which the rear member 38 and center member 40 together are a first link, the other rear member 39 and center member 41 together are a second link, and the front members 42-43 are the other two links, and in which the four articulations of the linkage are the screws 44, 48, 58 and 59. The first and second links, and hence the entire linkage, is locked by the cross-link assembly 46-47. The effective length of the linkage is adjusted by varying the lengths of the first two links, and namely by changing the registration of the sets of holes 50 and 51 and shifting the screws 52 through 54 accordingly. The width across the widest part of the other two links 42-43 of the four-bar linkage is varied by laterally expanding or retracting the linkage by articulating it with the cross-link assembly 46-47 disconnected. The cross-link assembly not only serves to lock the linkage after adjustment but also permits ready adjustment of the center strap posts lengthwise of the crampon.

It is important to note that the design of the parts is such as to provide production economies. A right foot crampon has been illustrated in the drawing. For a left foot crampon the rear elements 38-39 can remain unchanged, and the center cross-links 46-47, center members 40-41 and front members 42-43 need only be turned over during fabrication and the respective point elements and posts bent in the opposite directions from the right foot version. Thus, the present invention not only provides a rigid crampon with great versatility of adjustment, but also provides a unit that only requires a minimum of parts and fabrication dies to manufacture a right and left pair.

From the above description, it is seen that a crampon according to the present invention can be applied to a large variety of boot types, sizes and dimensions in a simple, safe and reliable manner insuring that the point elements 26-27 can always be at least as far out laterally as the overlying outer edge portions of the boot.

The invention is susceptible to modifications and changes all of which fall within the scope of the inventive concepts and ideas. The materials and dimensions can be varied in accordance with the requirements.

Claims

The embodiments of the invention in which a particular property or privilege is claimed are defined as follows:

1. An adjustable crampon comprising:

a closed four-bar articulated linkage having two front and two rear bars with integral point elements depending at their outer edges and the front bars being shaped to generally conform with the periphery of a boot sole, forwardly of the instep,

length adjusting means for adjusting the length of the two rear bars,

and adjustable-length cross-link means laterally interconnecting the two rear bars between said length adjusting means and said front bars for locking the linkage after the width between the rear ends of the front bars had been adjusted.

2. An adjustable crampon according to claim 1 in which said cross-link means has strap connecting means at its opposite ends and is adjustable in location length-wise of said two rear bars.

3. An adjustable crampon according to claim 1 in which the two front bars turn inwardly and overlap at the front, and front adjustable pivot means between said overlapped portions of the front bars for selectively varying the distance between the front bars at the front thereof outwardly of their said portions.

4. An adjustable crampon according to claim 3 in which the two rear bars turn inwardly and overlap at the rear, and rear adjustable pivot means between said overlapped portions of the rear bars for selectively varying the distance between the rear bars at the rear thereof outwardly of their said portions.

5. An adjustable crampon according to claim 1 in which said front bars each have a respective upstanding sole engaging post at its edge near the front thereof and in which said rear bars each have a respective upstanding heel engaging member near its rear end.

6. An adjustable crampon according to claim 5 in which said cross-link means has strap connecting means at its outer ends and in which said posts and heel engaging members also have strap engaging means.

7. An adjustable crampon according to claim 1 in which the rear end portions of the front bars overlap the front end portions of the respective rear bars, a respective pivot element extending through each set of said overlapped portions, a respective hole in one of said overlapped portions of each set spaced endwise thereof from the respective pivot screw and registering with a lateral slot in the other of said overlapped portion of the set, and a respective clamping element extending through said hole and registering slot.

8. An adjustable crampon according to claim 1 in which said bars are generally flat and overlap the adjoining bars, said rear bars each comprising a respective rear member and a center member which overlap one another and have respective sets of holes at the overlap for selectively receiving fastening elements therethrough comprising said length adjusting means.

9. An adjustable crampon according to claim 8 in which the sets of holes in the center members extend forwardly of the rear members and receive fastening elements passing through respective ends of said cross-link means.

10. An adjustable crampon according to claim 8 in which said rear members are on the upper side of their overlap with the center members, and said center members are on the upper side of their overlap of the front bars, said cross-link means comprising two overlapping links which engage the upper side of said center members.

11. An adjustable crampon comprising:

an elongated open frame assembly providing around its periphery a plurality of depending points and providing front and rear upstanding boot engaging means near its opposite ends,

articulating means for selectively varying the central width of the frame assembly relative to the width of the frame assembly near its ends,

extensible means in the frame assembly for selectively varying its length,

and locking means including laterally extending means of adjustable effective length operatively connected to the frame assembly for making the crampon rigid after width adjustment.

12. An adjustable crampon according to claim 11 in which said laterally extending means is adjustable in location endwise of the frame assembly independently of said extensible means and has upstanding means at its ends independent of said front and rear means for connecting to boot attaching means.