US3410561A

US3410561A - Simulated golf game

Info

Publication number: US3410561A
Application number: US482721A
Authority: US
Inventors: Ekstrand James
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-08-26
Filing date: 1965-08-26
Publication date: 1968-11-12
Anticipated expiration: 1985-11-12
Also published as: GB1120717A

Description

12, 1963 J. EKSTRAND SIMULATED GOLF GAME 4 Sheets-Sheet 1 Filed Aug. 26, 1965 INVENTOR JAMES EKST/M/VD ATTORNEYS 1963 J. EKSTRAND SIMULATED GOLF GAME 4 Sheets-Sheet 2 Filed Aug. 26, 1965 S R Y m N R E m 0 M m 5 1 m 1 8 flw m A J 4 W: W w E 7 Ma 0 r o m 40 W 2 o m m e I m M. 2 D w w m 0 Ow w v ON -TO m E o m w 0 w m 2 m H 0 m E L5 0 w m 5 Y w o RF 0 mm. 7 Wu 6 M 6 F F Nov. 12, 1968 J. EKSTRAND 3,410,561

SIMULATED GOLF GAME Filed Aug. 26, 1965 4 Sheets-Sheet 3 3,410,561 SIMULATED GOLF GAME James Ekstrand, 4301 45th Ave., Sacramento, Calif. 95824 Filed Aug. 26, 1965, Ser. No. 482,721 Claims. (Cl. 273-134) ABSTRACT OF THE DISCLOSURE A simulated golf game apparatus including a playing box provided with a transparent playing surface and carrying a roll of web material marked with indicia representing the several holes of a golf course, including traps and obstructions thereon, to simulate the appearance of a golf course, said web material being mounted on spaced reels and disposed to be transferred from one of the reels to the other under the transparent playing surface, the transparent playing surface being provided with a plurality of concentric circles, the reels being shiftable along the axes thereof to position the green of a particular golf course portion under the concentric circles on the transparent playing surface, disc-like members being secured to the ends of the shafts upon which the reels are mounted and an elongate tension strip secured around said disc-like members to prevent inadvertent rotation of the shafts during play, said apparatus further including an accessory golf cart-like device having a plurality of slots for accommodating a plurality of fan shaped simulated clubs positioned on the golf cart, a spinner for controlling the order of play, and tables and height and distance indicia charts for determining the distance and path of flight of a simulated golf ball.

This invention relates to an indoor game, and more particularly to one which closely simulates the actual conditions of playing including the normal rewards and vicissitudes of the actual game of golf.

Those who are proficient at golf realize that physically the game is a matter of muscular coordination but that the game has an important mental element. For example, whether to go for broke for a birdie and accept the concomitant risk of bogeys or double bogeys, or whether to play it safe and accept a par, is a mental decision which must weigh the probabilities of success and the value thereof against the probabilities of failure and the cost thereof. It is axiomatic, of course, that those that never exercise an opportunity for a low score or those that take all chances however remote will not succeed in the game of golf or in the game of the instant invention.

An object of the instant invention is to provide an indoor game which simulates the game of golf to all extents practicable.

Another object of the instant invention is to provide a game in which a plurality of simulated golf holes may be viewed seriatim under a transparent playing sheet.

Still another object of the instant invention is to provide a transparent playing sheet having a plurality of concentric circles at one end thereof with a sheet of material underlying the transparent playing sheet carrying a plurality of indicia representing a golf hole including a green, the green directly underlying the concentric circles.

Other objects and advantages of the instant invention reside in the combinations of elements, arrangements of parts, and features of construction and operation, all as will be pointed out more fully hereinafter and disclosed in the accompanying drawings wherein there is shown a preferred embodiment of this inventive concept.

In the drawings:

FIGURE 1 is a top plan view of a playing box of the States atent instant invention, certain parts being broken away for clarity of illustration;

FIGURE 2 is a transverse cross-sectional view of the playing box of FIGURE 1 taken along line 2-2 thereof and viewing in the direction of the arrows;

FIGURE 3 is a longitudinal cross-sectional view of the playing box of FIGURE 1 taken along line 3-3 thereof and viewing in the direction of the arrows;

FIGURE 4 is a schematic view of a pair of sheet-carrying rollers interconnected by a tensioning device to preclude inadvertent unwinding of the rollers.

FIGURE 5 is a pictorial view of an accessory showing a golf cart-like device having a plurality of slots therein accommodating .a plurality of fan shaped sheets known as clubs;

FIGURE 6 is a plan view of a fan shaped sheet utilized with the playing box of FIGURE 1 and known hereinafter as a golf club;

FIGURE 7 is a view illustrating a plurality of cards positioned in the golf cart of FIGURE 5 and providing a plurality of additional chance factors;

FIGURE 8 is a plan view of a spinner utilized with the playing box of FIGURE 1 and the golf club of FIGURE 6;

FIGURE 9 is an enlarged plan view of a portion of the playing box of FIGURE 1 showing the juxtaposition of a plurality of concentric circles and an underlying green;

FIGURE 10 is a representative table utilized when the play of a given hole has reached the green;

FIGURE 11 is a plan view of one form of obstacle on a golf course, known as a sand trap bunker;

FIGURE 12 is an imaginary cross-sectional view of the sand trap of FIGURE 11 taken along line 12-12 and viewing in the direction of the arrows;

FIGURE 13 is a plan view of a plurality of common golf course obstacles showing the path of a golf ball thereover;

FIGURE 14 is an imaginary view of the several obstacles of FIGURE 13 as may be seen from line 1414 wh n viewing in the direction of the arrows;

FIGURE 15 is a partial plan view of another obstacle commonly found on a golf course which is illustrated as a ravine.

Referring now to the drawings in detail, wherein like reference characters designate like elements throughout the several views thereof, there is indicated generally at 10 the game of the instant invention having as its major components a playing box shown generally at 12, a golf club shown generally at 14, a golf cart designated generally at 16 and a chance selection device or spinner denominated generally at 18.

Playing box 12 is preferably a rectangular structure made of any suitable material such as plastic, cardboard, metal, wood or the like having

longitudinal walls

20, 22, perpendicular

transverse walls

24, 26, a bottom wall 28 and a sheet-receiving surface 30 supported from bottom wall 28 by a plurality of transverse interior walls 32 and a pair of longitudinal interior walls 34. As may be seen in FIGURE 3, transverse interior walls 32 are spaced from

transverse walls

24, 26 to provide a pair of rollreceiving compartments indicated generally at 36, 38.

Playing box 12 is provided with a removable top or cover shown generally at having depending side edges 42 releasably secured to playing box 12 by a plurality of V-shaped corner braces shown generally at 39 providing a first elongated slot 41 receiving the intersections of

longitudinal walls

20, 22 and

transverse walls

24, 26. Brace 39 also has a second slot 43 receiving side walls 42 of cover 40. Although

slots

41, 43 of brace 39 are illustrated as straight, it will be appreciated that they may be slightly corrugated in order to tightly receive

walls

20, 22, 24,

3 26, 42. Alternatively,

walls

20, 22, 24, 26, 42 may be glued or otherwise secured in

grooves

41, 43. Cover 40 has a generally longitudinal slot 46 with a transparent playing sheet 48 secured to top wall 44 coextensive with slot 46.

Positioned in each of roll-receiving

compartments

36, 38 is an identical sheet receiving reel shown gnerally at 50, 52 having a central shaft 54 rotatably mounted in an aperture in wall and rotatingly received in a slot in wall 22 with a wire retainer shown generally at 55 precluding shaft 54 from inadvertently rising in the slot in wall 22. Wire retainer 55 includes an inverted U-shaped wire 57 straddling shaft 54 and a pair of perpendicular prongs 59 extending through wall 22 with any suitable means precluding prongs 59 accidentally being dislodged. Shaft 54 fixedly carries a pair of spaced apart circular flanges 56 with a cylindrical spool 58 providing a slot 60 fixedly mounted on shaft 54 between flanges 56. A course roll 62 is mounted on one of

sheet receiving reels

50, 52 and engaged with the other with a portion of course roll 62 lying between sheet receiving surface and transparent playing sheet 48.

Each of

reels

50, 52 is equipped with a handle shown generally at 64 secured to shaft 54 by a transverse pin 65 and providing a knob 66 for rotating shaft 54. Mounted on handles 64 are a plurality of radially extending protuberances 67 retaining a tensioning member 68 having generally semicircular ends 70 in the position shown in FIGURES 1, 2 and 4. Tensioning member 68 is preferably an elastic rubber-like material to preclude the in advertent unwinding of either of handles 64. In the event that a single tensioning member is insufficient to avoid unwinding of handles 64, an additional one may be placed on the other side of protuberances 67.

Course roll 62 is provided with a plurality of indicia representing the number of the hole, the par thereof, and the distance from tee to green. Roll 62 also includes a considerable number of symbols 74 representing sand traps or bunkers, another group of symbols 76 representing trees or the like and a closed irregular line 78 representing the green, with a tee being shown by a closed line 80. It will be seen that the manipulation of handles 64 will position a given golf hole of course roll 62 between playing surface 48 and surface 30 with green 78 being positioned adjacent one end of playing box 12. It should be understood that any suitable golf course obstacles may be represented on course roll 62 by appropriate symbols.

An important feature of the instant invention resides in a plurality of concentric circles 82 aflixed to transparent playing sheet 48 as may be seen in FIGURES 1 and 9. Circles 82 may be painted, etched, or positioned by a decal or any other suitable means on either side of transparent sheet 48. A center 84 of concentric circles 82 represents the hole or cup location with selected ones of circles 82 being associated with a numerical indicia 86 representing the radius of that particular circle and giving the distance from the selected circle to cup 84.

It should be apparent that cup 84 may be positioned in a plurality of locations upon green 78 by rotating one of handles 64 to allow for playing variations in course roll 62 in much the same manner that the cup on any given green of a golf course is periodically moved from location to location. In the event that course roll 62 presents a hole having a dog leg, which is a term of art indicating a golf hole whose fairway angles sharply to left or right intermediate tee and green, course roll 62 may be shifted laterally along with shafts 54 to vertically align green 78 and cup location 84. It should also be noted that the configuration of green 78 and the obstacles adjacent thereto may be changed with the change of any hole by merely printing different configurations on course roll 62. It should also be apparent that a plurality of rolls may be provided to simulate different golf courses.

As may be seen in FIGURE 6, a simulated golf club 14 includes a transparent sheet 88, which is preferably fan-shaped as illustrated, but which may be of any suitable configuration, having a starting aperture 90 positioned on the longitudinal axis of the sheet. Extending from starting aperture 90 in the general direction of the longitudinal axis is a plurality of flight paths 92, each of flight paths 92 being associated with an indicia 94 representing the name by which the path is known. For example, a golf shot by a right handed person that veers sharply to the right is known as a slice, with a shot that veers slightly to the left being known as a draw, and a left handers shot veering sharply to the left being known as a slice, indicia 95 indicating the left handers directions in parentheses. A plurality of arcuate intersecting lines 96 represent given distances from starting point 90, the distances being represented by indicia 98 as measured in yards.

An aperture 100 is formed at the intersection of each of flight paths 92 and distance lines 96 for purposes more fully explained hereinafter. A second series of arcuate lines 102 are formed substantially parallel to distance lines 96 and are associated with indicia 104 to represent in feet the vertical height of a simulated golf shot throughout the flight path thereof. It should be apparent to one.

skilled in the art that flight lines 92, distance lines 96 and height lines 102 may be aflixed to sheet 88 in manners similar to the application of circles 82 to transparent sheet 48.

In the use of simulated golf club 14, starting aperture 90 will be positioned within the bounds of tee 80, as seen in FIGURE 1, with the remainder of transparent sheet 88 being positioned over playing sheet 48 extending generally toward green 78. As more fully explained hereinafter, the player will determine the flight path and the distance of his drive. For purposes of illustration, it is assumed that the player achieves a 230 yard drive. The player will position the center line of sheet 88 toward green 78 and will mark, as by a grease pencil or the like, with different players using different colored pencils in order to avoid confusion, through aperture 100 at the intersection of the draw flight path and the 230 distance line. This will result in a grease marking on transparent playing sheet 48 and will represent the individuals drive.

When the player prepares to make a second shot, he will select another golf club 14 having similarly arranged flight paths and distance lines to simulate the projected path produced by another type club, with starting aperture 90 thereof being placed over the previously marked grease spot. The process of determining the flight path and the distance of the next shot will be repeated, as explained hereinafter, such that the terminus of the second shot may be determined. Hopefully, the individuals second shot will reach green 78 at which time the putting operation may be conducted, as also more fully explained hereinafter.

As shown in FIGURE 5, golf cart 16 includes a body 106 which may be formed of plastic, wood, metal or the like, providing a plurality of slots 108 in which various simulated golf clubs 14 having varying distance and flight lines may be positioned. Golf cart 16 also includes a slot 110 in which a distance finder may be positioned, such a distance finder being comprised of a transparent sheet of material having a single straight line thereon with a plurality of intersecting distance markers similar to the simulated golf club of FIGURE 6. Golf cart 16 may also include a handle 112 secured to a framework 114 to which is mounted a plurality of wheels 116 which are preferably stationary in order to avoid inadvertent movement of golf cart 16.

Referring now to FIGURE 8, chance selection device 18 includes a planar board 118 having a bearing 120 rotatably carrying a spinner arm 122 in the configuration of a golf club and having a pointer 124 on the end thereof. Board 118 includes a first series of numbers shown generally at 126 providing numerical indicia 128 positioned circumferentially about bearing 120 for use in the putting Spinner arm 122 is rotated again and comes to rest on number 6. The player will then find the remaining distance between the ball and cup 84 by descending down column I to the to foot distance and then moving horizontally until numeral 6 is located which will indicate that between five and ten feet remain between the ball and cup 84. This is indicated by the player with a grease mark being made between the five and ten foot circles, such as at 138, the five foot circle being designated at 188, the area within the circle being preferably white for ease of identification.

The player again spins arm 122 to make another putt with numeral 1 appearing. It will be seen from column II that the player did not succeed in sinking the third putt, so that he must now make a mark such as at 140, as determined from column III, within the five foot ring 188. The player again spins arm 122 with numeral 3 appearing. This does not make the fourth putt, as determined from column II, and the player makes two additional marks in the white center, one as at 142 and the fifth and final putt being marked in cup 84. The player will then tabulate the number of shots taken, it being remembered that two shots were taken to reach green 78 with a total of five putts being made for a total of 7 on the hole. The players may record their separate scores on a score card in order to determine the eventual winner. The player previously putting may erase the grease marks on green 78, as by rubbing with a clean cloth, so that the next player may putt out.

Although it has been found that the previously discussed game provides a very interesting pastime, it has been found desirable to provide more sophisticated difficulties that normally appear during the course of a golf game. Accordingly, 'sand traps 74 positioned intermediate tee 80 and green 78, which are known as fairway bunkers, may be provided with a plurality of

separate portions

144, 146, 148 of decreasing areas of difficulty. The cross-sectional view of a conventional fairway bunker may be seen in FIGURE 12 where the most difficult section 144 lies adjacent the forward end thereof which is customarily upwardly inclined toward green 78. Section 146 is an area of intermediate difliculty with section 148 being the area of least difliculty.

When a players drive has entered bunker 74 he must first determine the distance from his present location to green 78, which may be done by utilizing the distance finder positioned in slot 110 of golf cart 16. Instead of utilizing the normal club for that distance, the player must take a shorter distanced club, such as a six iron, rather than a five iron, if in area 148 of least difliculty. If the player is in intermediate area 146 the player must choose a club twice removed in a direction of a lesser distance from the one he would normally take. For example, should the player normally use a five iron in order to reach the green, if in intermediate area 146, he must choose a seven iron. In a similar manner, if a player is in area 144, he must take a club of even shorter distance. This imposition of a penalty has its counterpart in golf plays as the player must be able to clear the uppermost edge 150 of trap 74 which can only be done by a shorter distance and higher trajectory club.

Another type of obstacle that makes the game of the instant device more interesting is shown in FIGURES 13 and 14. A bush 152, a small building 154, a large tree 156, a small tree 158 and a bush 160 are in the proposed line of flight of the player. This normally results because of a wild tee shot or drive which ends up in the rough. There are several manners in which a player positioned at 162 may avoid

obstacles

152, 154, 156, 158, 160, the most common of the methods being to clear all obstacles by a high flying shot. In order to conduct this type of shot with the game of the instant invention, an

indicia

164, 166, 168, 170, 172 representing the height of the obstacle, is associated with each of

obstacles

152, 154, 156, 158, 160. The player selects the desired simulated 10 golf club and aligns the center flight path thereof in the proposed direction of travel with starting aperture overlying grease spot 162 on playing surface 48, it being understood that the symbols of the aforementioned obstacles are printed on course roll 62.

The player will rotate spinner arm 122 to achieve a direction numeral which may be translated into a flight path by the direction table previously disclosed with another rotation of spinner arm 122 providing the appropriate distance figure. In order to determine whether the proposed shot cleared each of the aforementioned obstacles, the vertical height lines 102 of club 14 must be taken into consideration. FIGURE 13 is a view of what the player will visualize when club 14 overlies playing surface 48 with the path of the ball indicated by line 92 between grease spots 162, 174.

FIGURE 14 is an imaginary side view of the results of the previously mentioned obstacle avoiding shot, with lines 102 in conjunction with indicia 104 providing the vertical trace of flight path 92. From a comparison of FIGURES 13 and 14 and extending from left to right along flight path 92, it will be seen that the ball achieves the ten foot height before it reaches obstacle 152 which is ten feet in height. Since the ball is ascending, it will be seen that the ball will be between 10 and 30 feet high when it passes obstacle 152, thus clearing the same. It will be seen that each of

obstacles

154 and 156 will be similarly cleared. During the descent it will be seen that the 30 foot obstacle represented by small tree 158 will be passed before the 30 foot height of flight path 92 is achieved. Accordingly, the proposed obstacle avoiding shot has been successful, allowing the next shot to be conducted from grease spot 174. Conversely, trees or other similar obstacles may be marked so that shots may be made under them.

Another form of obstacles is shown generally at 176 in FIGURE 15 and includes a deep ravine 178 having

banks

180, 182. Ravine 178 may be considered out of bounds, which may be designated on course roll 62 and which results in the imposition of a penalty of two strokes. In the alternative, ravine 178 may merely result in an unplayable lie having the consequent requirement of lifting and dropping out with a penalty of one stroke.

Banks

180 and 182 are of varying degrees of shot making difliculty, such that the player must take a shorter distance club when playing from bank 180 and a club twice removed when playing from bank 182 in much the same manner that the penalties are imposed in sand trap 74, as previously explained.

It 'will be apparent that many types of obstacles may be provided on course roll 62, such as cliffs, rocky areas, heavy brush areas, beaches, and water hazards of varying types. Similarly, various types of rough may be designated on course roll 62 as by coloring deep rough a darker green than fairway rough and requiring a shorter distance club when playing from deep rough.

Another mode of clearing obstacles within ones line of flight is to attempt to curve the flight path of the golf ball around such intervening obstacles. In this manner of avoiding an obstacle, the player attempts to hit a controlled fade or controlled draw in which the ball will curve to the right or to the left respectively. It is axiomatic that attempted curve shots are not always successful, resulting in the player remaining in difliculty or behind an obstacle. Just as when playing golf, the player plans on the type of shot to hit, intending for it to travel between objects or around a close object, curving back into the fairway or onto the green 78.

The individual selects the appropriate simulated golf club 14 and aligns starting aperture 90 with the previously positioned grease spot with his desired flight path lying in the desired direction of travel. Spinner arm 122 will be rotated providing a number to be utilized with the controlled fade and draw tables immediately hereafter.

om 0A 0A 0A om 0A 0A 0A It: 0 Am Am 0 mm mm 9A Am 0 mm mm EA Am 0 mm Am 0 9A Am Mm 9A mm fifi 225 0A om om om 0A om om om 0A 0A om 0A 0A 0A om 0A 9A 0 mm mm Am Am 0 EA mm 9A Am 0 mm mm 0 9A Aw Mm PA mm 0 Am 585 232 om om 0A om om om 0A om 0A 0A om 0A 0A 0A 0A 0A I Am Am 0 9A mm mm Am 0 mm EA 0 9A Am Mm 9A mm 0 Am 9A 0 mm mm 55 5 M om om 0A om om om 0A om 0A om 0A 0A 0A om 0A 0A I Am mm 9A Am 0 mm mm 0 9A Aw Mm 9A 3 0 AA 9A 0 mm mm Am Am 0 om 0A om om om oA om om om 0A 0A 0A om 0A 0A 0A AA 0 mm 9A 0 9A Am Mm 9A mm 0 Am 9A 0 mm mm mm Am 0 mm mm 9A i w 0A 0A om 0A S on om 0A 0A 0A om 0A 0A 0A 0A 8 mm 5A o EA Aw mm mm mm 0 Am PA 0 mm mm mm Am 0 Am 3 9A Am 0 i h om om 0A om om om oA 0A 0A om 3 QA 0A 0A 0A 0A 0A 0A 0 Aw mm mm Am 0 Am 5A 2 0 Am mm 0 mm 9A Am 0 mm 9A 0 25 om 0A om 0A om 0A 0A 0A om om 0A om 0A om 0A 0A 0A om 0A 8 5A 0 Am 9A mm 0 Am mm 0 mm mm Am 0 mm 9A 0 0 Am Mm 9A i A 0A 0A om 0A om om om 0A om om oA om 0A 0A 0A om 0A 0A 0A om Am Am 2 0 Am mm 0 mm Am Am 0 mm mm o 0 Am Mm 9A EA 0 i A 0A 0A 0A om 0A 0A om om om 0A 0A 0A 0A 0A 0A 0A 0A 0A 0A 2 0 mm mm @A 0 mm 0 Am 0 mm mm 0 Am MA 0 EA mm 0 AAA 5A 2 0A 0A 0A om 0A om om om oA 0A om 3 QA 0A 0A 0A om 0A mm MA 0 EA 0 Am 0 mm 9A 0 Am VGA 0 9A mm 0 AAA Am mm 0 9A 22 0A 0A om 0A om om om 0A om 0A 0A 0A oA om 0A 0A 0A mm 9A Am 0 mm 9A 0 9A Am Mm 9A mm 0 Am EA 0 mm mm 9A Am 0 EA 6 A 0A om 0A 0A 0A om om om 3 0A 0A 0A om 0A 0A 0A 0A 0A om 1 I 0 ma 9A 0 0 Am MW 9A 9A 0 Am PA PA 0 Am mm 0 mm EA AHA A BM om om om 0A on 0A on on om 0A 0A 0A 0A 8 QA 0A oA om 0A 0 Am Mm 0 9A mm 0 Am 9A mm 0 9A mm mm o I] EA 0 Am 0 mm 9A 65: 0A om om om 0A om om 0A om @555 A4 mom emfimo zoAeoAmAA awn -5 on @N a K 8 mm K mm NN a a 2 E 2 S B 3 MA 2 2 S a w A. m. u A m N A Assuming for purposes of illustration that the player is a righthanded player and seeks to produce a controlled fade shot, Table II will be utilized as may be apparent from its title. Assuming that the player selects a four iron for making the shot and is provided with number 4 from spinner 18, the controlled fade table for righthanders will indicate a right center flight path which is reasonably close to the desired trajectory. Spinner 122 will be rotated again to provide a number to be used with the distance table in order to complete the shot determination. Assuming that pointer 124 stops at number 9, the distance table, with a 4 iron, provides a distance of 140 yards. The flight path should be checked against the symbols visible through transparent playing sheet 48 to determine if another obstacle was struck.

Any type of competition may be contemplated by the players including medal play in which the low scorer for a number of complete rounds is declared the winner or match play in which each hole is a separate battle, the winner of the most holes winning the play regardless of the total scores. Other types of competition, such as best ball, scotch foursome, handicap play or any known golf competition may be adapted to the play of the instant game.

It is now seee that there is herein provided an improved game having all of the objects of the instant invention and others, incuding many advantages of great practical utility and commercial importance.

Since many embodiments may be made of the instant inventive concept, and since many modifications may be made in the embodiment hereinbefore shown and described, it is to be understood that the foregoing is to be interpreted merely as illustrative and not in a limiting sense.

I claim:

1. A game apparatus for simulating golf, comprising:

a playing box provided with a transparent playing surface having a plurality of concentric circles proximate one end thereof;

an elongate Web course roll positioned under the playing surface carrying a plurality of symbols representing a plurality of golf course holes having the green representing portions thereof disposed in different positions relative to the sides of the roll; and

means carrying the course roll for moving said course roll incrementally from one side of the playing surface to the other to provide for longitudinal position ing of the simulated golf course greens under the playing surface, said means being so constructed as to permit the golf course roll to be shifted transversely of the elongate direction thereof for permitting the user to position the green thereon under the plurality of concentric circles proximate one end of the playing surface.

2. The structure of claim 1 wherein said transparent surface carries at least one numerical indicia adjacent one of said circles representing the distance between said one circle and the center of said circles.

3. The structure of claim 1 wherein said moving means includes a pair of reels disposed adjacent the ends of said transparent surface, each of said reels having a shaft journaled in said box, and elongated tensioning means connecting said shafts for preventing inadvertent rotation of said shafts.

4. The structure of claim 3 wherein said tensioning means includes a first substantially semicircular portion partially surrounding one of said shafts, a second substantially semicircular portion partially surrounding the other of said shafts, and a straight elongate resilient member connecting said semicircular portions.

5. The structure of claim 4 wherein said straight resilient member extends diagonally with respect to said shafts.

References Cited UNITED STATES PATENTS 1,520,081 12/1924 Purnell 273-134 1,928,768 10/1933 Sell a; a1 273-87X 2,180,049 11/1939 Hall 273 134 FOREIGN PATENTS 495,506 8/1953 Canada.

699,745 12/1964 Canada.

229,001 2/ 1925 Great Britain.

322,221 12/1929 Great Britain.

DELBERT B. LOWE, Primary Examiner.