US3570196A - Tower structure and adjustable clamping device - Google Patents

Abstract

A TOWER STRUCTURE AND ADJUSTABLE CLAMPING DEVICE FOR USE THEREWITH IN WHICH THE CLAMP IS FORMED TO FRICTIONALLY ENGAGE THE TOWER AT SELECTED VERTICAL HEIGHTS FOR SECURING A LOAD SUPPORTING ARM THERETO. THE TOWER IS FURTHER FORMED WITH A VERTICALLY EXTENDING INDEXING SURFACE AGAINST WHICH THE CLAMP BEARS AND MAY BE SECURED TO POSITION THE ARM IN HORIZONTALLY, VERTICALLY AND ANGULARLY INDEXED RELATION TO THE TOWER. THE LOAD SUPPORTING ARM IS CONSTRUCTED IN A MANNER WHICH ALLOWS THE MOMENT INDUCED BY LOADING THE ARM TO BE TRANSFERRED TO AND RESISTED BY THE ENGAGEMENT OF THE CLAMPING DEVICE WITH THE TOWER AND PARTICULARLY THE INDEXING SURFACE. A TOWER PARTICULARLY SUITED FOR USE AS A SKI LIFT TOWER IS DESCRIBED.

Description

March 1971 J. K. KUNCZYNSKI .57

TOWER STRUCTURE AXD ADJUSTABLE CLAMPING DEVICE Filed Nov. 2-1, 1968 2 Sheets-Sheet 1 44 'f If! 2% 44 INVENTOR.

Attorneys 2 Sheets-Sheet 2 J. K. KUNCZYNSKI TOWER STRUCTURE AND ADJUSTABLE CLAMPING DEVICE March 16, 1971 Filed Nov. 21, 1968 INVENTOR. Jan K. Kunczynski BY Qm J m/u. &

' Attorneys Fig.9

United States Patent O 3,570,196 TOWER STRUCTURE AND ADJUSTABLE CLAMPING DEVICE Jan K. Kunczynski, P.O. Box 2181, Olympic Valley, Calif. 95730 Filed Nov. 21, 1968, Ser. No. 777,799 Int. Cl. E04l1 12/00 US. C]. 52-40 9 Claims ABSTRACT OF THE DISCLOSURE A tower structure and adjustable clamping device for use therewith in which the clamp is formed to frictionally engage the tower at selected vertical heights for securing a load supporting arm thereto. The tower is further formed with a vertically extending indexing surface against which the clamp bears and may be secured to position the arm in horizontally, vertically and angularly indexed relation to the tower. The load supporting arm is constructed in a manner which allows the moment induced by loading the arm to be transferred to and resisted by the engagement of the clamping device with the tower and particularly the indexing surface. A tower particularly suited for use as a ski lift tower is described.

BACKGROUND OF THE INVENTION The present invention relates to the construction of towers or supporting structures and clamping devices for use therewith, and more particularly relates to the construction of ski lift towers.

There are many applications in which tower structures are constructed for the support of various other devices. One such example is a ski lift tower in which the upright post of the tower is provided with a laterally extending arm on which a series of sheaves or pulleys are mounted. The lift cable is thereby supported for advancement over the sheaves. There are numerous other examples of similarly constructed towers or support structures. In many of these structures, it is highly advantageous, if not absolutely mandatory, that the tower be constructed so that the laterally extending arm can be readily adjusted to various heights in relation to the ground or supporting surface.

In the ski equipment industry, it has been found particularly necessary to provide a tower which may be quickly and easily adjusted to various vertical heights in order to accommodate the often wide fluctuation in snow depth. The difference between a ski lift and chair lift is instructive in order to better understand the need for an adjustable tower and to better understand the tower construction of the present invention. A ski lift is a skier conveying device in which the skier is transported up the mountainside while his skis are in contact with the snow. Thus, the skier in effect skis up the mountain while being pulled by the device. Examples of such devices are POMALIFTS, T-bars, and J-bars. A chair lift by contrast, is a device in which the skier is physically lifted off the snow and is transported a spaced distance above the snow up the mountainside, usually while in a sitting position.

As will be readily understood, as the snow depth varies, the distance between the cable on a ski lift or chair lift and the surface of the snow will correspondingly vary. In the case of a chair lift, however, this distance is not extremely critical since the chair lift may be designed so the skier engages is usually connected to the towing cable by means of an extensible member, such as a spring biased cable or arm. Thus, the skier engaging apparatus itself will accommodate variations between the cable height and the snow surface, within certain limitations. Snow depths in the Western United States, however, may vary as much as 20 feet, which is far beyond the tolerable variation inherent in the skier engaging apparatus. Moreover, it has been found that a substantial inefficiency in the power required to operate the ski lift occurs when the distance between the cable and the snow surface falls outside the recommended range. That is, attempts to rely upon the extensible nature of the ski lift apparatus in order to accommodate different snow depths may result in substantial inefficiency of operation of the ski lift.

Accordingly, ski towers have been constructed in the past which are formed so that the cable hanging arm can be vertically adjusted. Past tower constructions, however, have been very unsatisfactory in several respects. One such tower has utilized pairs of flexible metal bands which must be contracted or cinched down by several bolts against a cylindrical post which forms the vertical or upright portion of the tower. The bands are constructed in a manner similar to bands which are used as clamps for garden hoses and similar cylindrical members. In order to adjust this type of tower, however, many bolts have to be loosened, and the Weight of the cable on the arm will cause the bands to bind against the vertical post. Thus, adjustment of such towers may require heavy equipment in order to avoid binding of the bands. Moreover, and very importantly, in the process of obtaining vertical adjustment of towers of the above-described type, the angular alignment of the sheaves with the desired line of the cable is very often lost. Thus, after vertical adjustment, considerable time and effort must be spent in order to align all of the towers with the desired cable path. Since in places where the snow depths vary considerably tower adjustments must be made as often as five times a year, this type of adjustable tower has been found undesirably costly to adjust. As a result of the high costs, adjustment of the towers as often as might otherwise be required has been inhibited, and the period during which the ski lift is operating under optimal conditions has been reduced.

SUMMARY OF THE INVENTION The apparatus of the present invention is comprised briefly of an adjustable tower and a clamping device for use therewith in which the tower is formed to provide a vertically extending indexing surface against which the clamping device may be secured at selected vertical heights. The clamping device is comprised of a pair of opposed clamping members, one of which is formed with a bearing portion for engagement of the indexing surface on opposed bearing areas at vertically spaced points on the tower. An actuator means is provided to allow advancement and retraction of the members in order to generate clamping forces therebetween and cause engagement of the tower and the indexing surface. The clamping device is provided with a cable supporting arm, arm and engagement of the indexing surface with the bearing portions will automatically result in clamping of the cable supporting arm relative to the tower in fixed horizontal and vertical relation thereto and in a manner which prevents rotation of the arm about the longitudinal axis of the tower (a fixed angular relation to the tower).

The tower is also preferably formed with the cable supporting arm parallel to the plane of engagement of the clamping member with the vertical portion of the tower, which results in the inducement of a moment in a plane transverse to the direction of advancement of the opposed clamping members. The clamping member is further formed for the transfer of the induced moment to the bearing portions and then to the indexing surface of the tower. Additionally, the tower and clamping device are formed so that the weight on the cable hanging arm tends to cause the clamping members to be urged apart and released upon release of the actuator means.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a front elevational view of a tower constructed in accordance with the present invention.

FIG. 2 is a side elevational view taken along the plane of line 22 of FIG. 1.

FIG. 3 is an enlarged cross sectional view taken on the plane of line 33 in FIG. 1.

FIG. 4 is an enlarged cross-sectional view taken on the plane of line 44 in FIG. 1.

FIG. 5 is an enlarged cross-sectional view of an alternative embodiment of the clamping device and tower of the present invention taken on substatially the same plane as FIG. 3.

FIG. 6 is an enlarged side elevational view of one of the clamping members of another alternative embodiment of the device of the present invention.

FIG. 7 is a side elevational view taken on the plane of line 7--7 of FIG. 6.

FIG. 8 is a side elevational view of still a further alternative embodiment of one of the clamping members constructed in accordance with the present invention.

FIG. 9 is an enlarged cross-sectional view of an alternative embodiment of the tower construction and clamping device of the present invention taken on the same plane as FIGS. 3 and 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 through 4, the tower construction of the present invention can be seen to be comprised of a pair of vertical posts 11 and 12 defining a vertically extending slot or opening 13 therebetween. Mounted in frictioal engagement with the post is a clamping device generally designated 14. Clamping device 14 is provided with a laterally extending arm 16 secured to plate member 17, which acts as a bearing member or bearing portion of the clamping device. Plate 17 engages posts 11 and 12 on the outwardly facing sides thereof at positions 18 and 19 thereon (best seen in FIG. 3). In addition, the clamping device is provided with a second member 21 (also best seen in FIG. 3), which as here illustrated is triangular or more specifically V-shaped, and members 17 and 21 are connected for advancement toward each other by actuator means 20, which is comprised of a pair of bolts 22 and 23 and nuts 27 and 28. Clamping member 17 is further provided with a vertically elongated triangular or V-shaped protrusion or member 26 which engages opposed inwardly facing surfaces of the tower.

When employed as a ski lift tower, the apparatus illustrated in FIGS. 1 through 4 functions in a highly advantageous manner. Arm 16 may be frictionally secured to posts 11 and 12 by placing member 21 on one side of posts 11 and 12, inserting bolts 22 and 23 through vertical slot 13 and mounting member 17 thereto by means of nut 27 and 28. The nuts are then cinched down which advances members 17 and 21 toward each other causing them to bear upon and frictionally engage the posts. In order to position the post at any selected vertical height, nuts 27 and 28 may be loosened and arm 16 raised or lowered whereupon the nuts will again be tightened.

It is an important feature of the tower construction of the present invention that the arm will at all vertical heights be automatically clamped in the same relationship to the tower. As may best be seen in FIG. 3, V-shaped members 21 and 26 engage opposed inwardly facing surfaces of posts 11 and 12. Thus, rotation of arms 16 about axis 24 of the tower is prevented, and the arm will be clamped into angular registration with the tower for all vertical heights. As has been previously described, this is an extremely important for ski lift towers in that it eliminates the necessity of readjusting the alignment of the sheaves every time vertical adjustment is accomplished. In this regard. the sheaves or pulleys (not shown) are mounted on end 31 of arm 16, and the arm is provided with perpendicularly related adjustment screws 32 and 33 in order to allow for initial alignment of the sheaves. While the posts 11 and 12 are set so that once arm 16 is clamped thereto, it will be substantially in alignment with the desired cable line, some fine adjustment of the alignment of the sheaves is usually necessary at the time the arm is first clamped to the tower. This can be accomplished through screws 32 and 33. After this initial alignment adjustment has been made, however, arm 16 may be vertically adjusted without any further need to employ the adjustment screws.

In order to prevent binding of clamping device 14 to the tower while still affording a clamp which will enable substantial clamping forces to be generated, the clamping device is preferably additionally formed in a manner to cause clamping members 17 and 21 to Wedge between the posts and yet be urged apart upon release of the clamping force generated by the actuator means 20.

V-shaped member 21 and V-shaped member 26 apply a clamping force to the posts through a wedging action as they enter opening 13. Thus, these opposed wedges tend to advance toward each other until high clamping forces are generated between the opposed faces of the posts. This engagement of the posts assists the plate 17, with the forces generated in member 21 opposing the forces generated in members 26 and 17. Member 17 effects a limit as to the extent to which member 26 can be advanced into slot 13 by substantially simultaneously engaging positions 18 and 19. It is preferable that plate 17 engage posts 11 and 12 slightly after member 26 engages the inwardly facing sides of the posts in order that the wedge effect may be initiated.

The weight of arm 16, the sheaves, the cable and associated ski lift equipment will cause a downward force F at the end of arm 16. This force in turn induces a moment M parallel to the plane of plate 17 and transverse or, as illustrated, substantially perpendicular to the direction of advancement of bolts 22 and 23. In prior tower constructions, this moment has caused binding of the clamping device against the tower. In the apparatus of the present invention, however, member 26, which is preferably secured to plate 17 by means of welds 34 and 36, will tend to rotate in the direction of moment M upon release of nuts 27 and 28. Since, as best may be seen in FIG. 2, member 26 is elongated and extends and engages a substantial vertical length of the posts and since it is formed with a V-shaped cross section, this rotation about the horizontal axis of the member will tend to urge member 26 and correspondingly clamping member 17 away from opposed member 21. Thus, the weight of the cable can be used to free the wedging clamping device from the posts in order that it may be vertically adjusted.

R is also an important feature of the clamping device of the present invention that it is formed in order to transfer the moment induced by the weight of the cable positively to the tower so that it may be resisted thereby. This aagin is achieved by the construction of member 26 which engages posts 11 and 12 tangentially along lines 37 and 38. Moment M is thereby resisted by opposed vertically spaced bearing areas along the upper portion of line 37 and the lower portion of opposed line 38.

In order to achieve the advantages of the clamping apparatus of the present invention while still maintaining easy access to the top of the tower, member 21 is preferably formed so that it does not extend beyond the recess between post 11 and 12. This construction allows for the welding of ladder rungs 39 to the back side of the tower for access to any portion thereof without interference with the vertical adjustment of arm 16.

In the tower illustrated in FIGS. 1 through 4, posts 11 and 12 are preferably embedded in concrete block 41 which is constructed along the lift line at a predetermined position. Additionally, the posts may be joined at the lower end by members 42. Although the tower of the present invention has herein been described as extending vertically, it is common practice for the towers to be mounted at a considerable angle to the vertical. As will be understood, the advantages of the construction of the tower of the present invention will also accrue even for installations wherein the tower extended horizontally.

The upper end of the tower is preferably joined by member 43 which is welded to post 11 and 12. In addition, a second arm 44 may be mounted across the top of the tower on plate 46. This arm is used for the return of the ski lift cable after its direction is reversed at the top of the lift line by means of a conventional horizontal wheel (not shown). Sheaves (not shown) are similarly mounted on end 47 so as to convey the cable to the bottom of the lift line, and sheave alignment screws 48 and 49 may be provided on the arm. As shown in FIGS. 1 and 2, arm 44 is mounted in fixed position on the top of the tower since the distance between the snow surface and the cable is not critical upon return of the unloaded lift apparatus to the bottom of the hill. It is quite feasible and in some instances advantageous, however, for arm 44 to be formed as an extension of arm 16, in the opposite direction, whereby both arm 16 and arm 44 would be simultaneously vertically adjustable. Such a construction is shown in the alternative embodiment illustrated in FIG. 9.

The tower of the present invention is also further formed with ears or U-shaped eyelets 511, 52, 53 and 54. These eyelets can be used in order to hoist arm 16 by means of simple pulleys attached to ears 52, 53, or 54 and fixed car 51. Thus, while the clamping device of the present invention is formed to prevent binding, it is still often helpful to be able to use the combination of eye lets in order to lift the arm against the weight of the cable and its own mass.

While certain specific alternative embodiments of the clamping device and support structure of the present invention have been found to be especially advantageous and are illustrated and described below, it is instructive to consider generally some further alternative embodiments of the present invention. For example, it is within the scope of the present invention to form posts 11 and 12 as a single unitary post having a slot 13 therein. Moreover, the slot 13 could be formed as a recess or a pair of opposed recesses with members 21 and 26 engaging the recess. In such a construction, the clamping action could be achieved by means of bolts which extended around the outside of the unitary post. This construction could be illustrated by reference to FIG. wherein plates 62 and 67 could be extended beyond posts 64 and 66 and a pair of bolts used to connect and draw the plates toward each other mounted on each side of the tower rather than through slots 69.

Still further instead of a recess formed between two posts the longitudinally extending indexing surface could be formed by a longitudinally extending protrusion. In such a structure, the actuator means for drawing opposed post engaging clamping members toward each other might again span around the outside of the post as above de scribed in connection with an embodiment which uses recessses instead of slots. In both such illustrations, at least one of the clamping portions would be formed with a longitudinally extending bearing portion which would engage the indexing surface on opposed bearing areas at longitudinally spaced positions thereon. Thus if a protrusion is used instead of a recess or slot, the bearing portions would engage oppositely outwardly facing areas on the protrusion in contrast to the engagement of oppositely inwardly facing areas of a recess. As above described, the engagement of oppositely facing areas of the indexing surface is particularly advantageous when the loading supporting arm is formed in a manner so as to induce a moment which is transverse to the direction of advancement of the clamping members.

Referring now to FIG. 5, there is illustrated an alternate embodiment of the clamping device and tower structure of the present invention which has been found to be particularly advantageous. In this embodiment, arm 61 is secured to plate member or first clamping member 62, which has secured thereto a V-shaped elongated bearing portion 63. The tower structure is again formed with a pair of tubular posts 64 and 65, and a second plate 67 acts as a second clamping member and engages an oppositely facing segment of the tower, namely, the opposite sides of posts 64 and 66. Member 67 is also preferably provided with a V-shaped protrusion 68, and the posts extend in parallel spaced relation to define an opening or slotted space 69 therebetween. Extending through slotted openings 69 are a pair of bolts 71 having nuts 72 on the end thereof. This construction differs from that set forth in FIGS. 1 through 4 in that member 21 has, in effect, been provided with a second plate 67, to form a pair of opposed parallel clamping plates which tangentially engage opposite sides of the cylindrical posts. This clamping construction has the advantage affording more surface area for the frictional engagement of the posts while retaining the other advantageous characteristics of the clamping structure previously described. It also has the advantages of transmitting the moment about the axis of advancement of the plates 62 and 67 directly to the tower through member 63, of angularly registering arm 61 relative to the longitudinal axis of the tower, and of preventing binding of the clamping members upon release of the nuts 72. It should be noted that in this construction nuts 72 are on the opposite side of the tower which affords slightly greater access for tools during adjustment. It is also possible to form the bolt opening in members 67 or 68 with threads to allow the bolts to be screwed directly into the second member.

Referring now to FIGS. 6 and 7, an alternate embodiment of a clamping member constructed in accordance with the present invention is illustrated. In this form of the clamping device, plate 81 (which is equivalent to clamping member 17), has welded thereto V-shaped protrusions 82 and 83. In a manner as above described, these members are formed with openings to which a pair of bolts 84 and '86 extend. Mounted on the exterior side of plate 81 is a load bearing arm 87, upon which sheaves may be mounted as above described. The force F similarly induces the moment M in plate 87. The dotted lines A, B, C and D represent lines of contact at which members 81, 82 and 83 tangentially engage cylindrical posts (shown in phantom). Thus, the moment M is resisted by engagement of the posts along line A in member 82 and oppositely facing line B in member 83 to provide a balancing moment.

FIG. 8 illustrates still a further embodiment of a clamping member constructed in accordance with the present invention in which the V-shaped protrusion 91 is formed as a single piece and the flat post engaging plate is formed as two members 92 and 93. This type of split plate clamping member is probably most suitable for use as the clamping member on the back side of the tower in a manner similar to member 67 of FIG. 5.

Referring now to FIG. 9, a still further alternative embodiment of the clamping device and adjustable tower of the present invention is illustrated. In this apparatus, posts 96 and 97 are constructed as tubes having an octagonal cross section. A first clamping member 98 extends between and engages both of the posts along a flat side thereof. A second clamping member 99 is provided to engage the opposite side of the posts. In order to achieve the wedging action of the clamping device of the present invention while still retaining the non-binding characteristics and positive transfer of forces to the posts, members 98 and 99 are provided with bearing portions 101 and 102 which have a convexly shaped outer surface to engage the inwardly facing planar sides of posts 96 and 97 in tangential relation. As before described, the actuator means is comprised of a bolt 103 secured by nut 104 (preferably a pair of bolts are employed). In addition, this embodiment incorporates a load bearing arm 106 and an oppositely extending return arm 107. Convex protrusions 101 and 10-2 extend vertically to engage posts 96 and 97 at vertically spaced opposed bearing areas in order to resist the moment induced in arm 106 upon loading thereof.

What is claimed is:

1. A clamping device for use with a pair of adjacent, generally parallel posts formed and positioned to provide an uninterrupted opening therebetween, said opening being defined by opposite inwardly facing indexing surfaces of said posts, comprising:

(a) a pair of clamping members formed to engage said posts on opposite sides thereof adjacent said opening, at least one of said clamping members having a longitudinally extending bearing portion of substantial length formed to protrude into said opening between said posts and simultaneously engage and bear upon both of said posts on said indexing surfaces at spaced positions thereon;

(b) actuator means formed to extend through said opening between said posts, said actuator means operatively interconnecting said clamping members and being formed to enable said clamping members to be advanced toward and retracted from each other; and

() load supporting means secured to the clamping member having said bearing portion, said supporting means being further formed to engage said posts in a manner which will prevent binding of said clamping members with said posts upon rotation of said clamping device in the plane of loading thereof.

2. A clamping device as defined in claim 1 wherein a first of said members is an elongated V-shaped member with the apex of said member providing said bearing portion and being formed to be positioned on one side of and between said posts for simultaneous engagement of said inwardly facing indexing surfaces of said posts upon clamping of said device thereto.

3. A clamping device as defined in claim 2 wherein a second of said members is formed as an elongated V-shaped member with the apex thereof formed to be positioned between said posts for simultaneous engagement of said inwardly facing index surfaces upon positioning opposite said first member, and said first and second V-shaped members are each centrally disposed on and secured to flat plates and said V-shaped members are formed to protrude from said plates a distance to enable substantially simultaneous engagement by said plates of parallel outwardly facing areas of said posts upon engagement by said V-shaped members of said inwardly facing indexing surfaces of said posts.

4. A tower structure including a vertically adjustable load supporting element comprising:

(a) at least two vertically extending posts positioned in side-by-side relatively spaced apart and generally parallel relation to define a vertically extending opening therebetween over a predetermined vertical height of said posts, said posts providing opposite inwardly facing vertically extending indexing surfaces which define said opening;

(b) first and second clamping members mounted on opposed sides of said posts adjacent said opening and formed to transmit clamping forces generated therebetween to said posts, at least one of said clamping members being formed with a protruding bearing portion, said bearing portion extending into said opening between said support posts and engaging and bearing upon said oppositely facing indexing surfaces at vertically spaced points thereon;

(c) actuator means extending through said opening between said posts and operatively connecting said clamping members, said actuator means being formed for relative advancement and retraction of said clamping members for the generation of clamping forces therebetween; and

(d) load supporting means secured to the clamping member formed with said bearing portion in fixed relation thereto whereby clamping'of said members to said posts positively indexes said clamping member and said load supporting means in a predetermined relation to said posts for any vertical height over said opening.

5. A tower structure defined in claim 4 wherein said indexing portion is formed to induce a wedging force between said posts upon advancement of said clamping members into engagement with said posts.

6. A tower structure as defined in claim 5 wherein said load supporting means is provided by an arm extending generally parallel to a line between the verticle axes of said posts and said bearing portion and indexing surfaces are further formed to cause said members to be urged apart upon release of the clamping forces by a moment about said actuator means generated by loading forces on said supporting means.

7. A tower structure as defined in claim 5 wherein said posts are cylindrical and said first member includes a plate formed, mounted and extending parallel to a line extending between the vertical axes of said posts and engaging said posts at points tangential to the periphery thereof, and said first member is formed with said bearing portion, said bearing portion being provided by an elongated V-shaped protrusion extending from said plate centrally thereon with the apex thereof extending into said opening between said posts and said V-shaped member is formed and mounted so that the sides thereof are in tangential engagement with said inwardly facing indexing surfaces upon engagement of said plate with said posts.

8. A tower structure as defined in claim 7 wherein said second member is formed and provided with a second elongated V-shaped protrusion extending centrally from said second member with the apex thereof extending into said opening between said posts and said second V-shaped protrusion is formed and mounted so that the sides thereof are in tangential engagement with said inwardly facing indexing surfaces of said posts, and said actuator means is provided by at least one threaded bolt extending between said posts to allow said clamping members to be urged by said bolt into clamping engagement with said posts.

9. A tower structure as defined in claim 6 wherein said posts are formed with a polygonal cross section to provide inwardly facing opposed fiat surfaces and said bearing portions are formed by an elongated convexly curved surface which protrudes away from one of said clamping members.

References Cited UNITED STATES PATENTS 805,240 11/1905 Sims 248227.l

2,932,511 4/1960 Bemis 5240X FOREIGN PATENTS 1,222,367 6/1960 France 52730 ROY D. FRAZIER, Primary Examiner J. F. FOSS, Assistant Examiner US. Cl. X.R.

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