Title:
LEG DEVELOPING DEVICE
United States Patent 3627315
Abstract:
A leg-developing machine for exercising and developing the important leg muscle and related muscle groups utilized by athletes in stressful contact sports, running and sprinting in natural postures, which comprises a pair of uprights adapted to be faced by the trainee and support the hands and shoulders of the trainee; a pair of reciprocative slidable skates, each to support a foot of the trainee; a pair of tracks each to guide one of the skates in substantial alignment with said uprights and adjustable resistance weights connected through to a pulley system each of the skates to present the desired resistance to the movement of the skates horizontally outwardly from the uprights.
US Patent References:
Amusement device
Turner - December 1924 - 1521487
Exercising apparatus
Pfaus - October 1955 - 2720396
Amusement device
Turner - December 1924 - 1521487
Exercising apparatus
Pfaus - October 1955 - 2720396
Application Number:
04/779283
Publication Date:
12/14/1971
Filing Date:
11/26/1968
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
482/135
International Classes:
A63B21/06; A63B23/04; A63B21/00; A63B21/062; A63B23/035; A63B21/06
Field of Search:
272/57.1,58,79-83
Primary Examiner:
Pinkham, Richard C.
Assistant Examiner:
Shapiro, Paul E.
Parent Case Data:
This application is a continuation of Ser. No. 530,506 filed Feb. 28, 1966 and since abandoned.
Claims:
I claim
1. A leg-developing device comprising:
2. The invention according to claim 1, in which said tracks are hinged to said frame so that they can be raised from an operative horizontal position to an inoperative substantially vertical position on said frame.
3. A leg-developing device comprising:
4. A muscle developing device comprising:
5. A muscle-developing device comprising:
6. A combination as defined in claim 5 in which said shoulder-engaging means has portions separately engageable by each of the trainee's shoulders.
7. a combination as defined in claim 5 in which said foot-engaging members are movable in a substantially horizontal plane, their paths of travel being substantially vertically aligned with said shoulder-engaging means.
8. A muscle exercising device comprising:
9. A combination as defined in claim 8 in which said weight means is adjustable in order to change the force which may be applied to the shoulder-engaging means through the body of said trainee.
10. A muscle developing device comprising:
1. A leg-developing device comprising:
2. The invention according to claim 1, in which said tracks are hinged to said frame so that they can be raised from an operative horizontal position to an inoperative substantially vertical position on said frame.
3. A leg-developing device comprising:
4. A muscle developing device comprising:
5. A muscle-developing device comprising:
6. A combination as defined in claim 5 in which said shoulder-engaging means has portions separately engageable by each of the trainee's shoulders.
7. a combination as defined in claim 5 in which said foot-engaging members are movable in a substantially horizontal plane, their paths of travel being substantially vertically aligned with said shoulder-engaging means.
8. A muscle exercising device comprising:
9. A combination as defined in claim 8 in which said weight means is adjustable in order to change the force which may be applied to the shoulder-engaging means through the body of said trainee.
10. A muscle developing device comprising:
Description:
This invention relates to a leg-developing device and more particularly, to a device for exercising and developing the hamstrings, the calf flexors, the quadriceps femoris, and the gluteal muscles.
The invention provides a new principle in leg development work. For the first time, full leg extension may be achieved with adjustable weight resistance whereby the hip extensor muscles may be brought into action in the natural neuromuscular patterns found in the football line stance position and in the semicrouch position used in track, swimming, wrestling and other sports. The extra leg strength derived in the driving action which occurs in the foregoing type of positions, and now which is possible for the first time in a device, according to the invention, induces substantially greater power in the legs so as to provide increased maximal acceleration for all sports.
In the past, all leg press machines used only the leg and thigh muscles with the hips in the flexed position and which did not allow the sequential use and development of the powerful gluteal muscles which are brought into play with the trunk in the fully extended position. In the use of the present invention, the trunk flexors and extensors are able to stabilize the pelvis in the extended position, thereby providing strong support for the action of the legs. The great driving power of the legs is fully utilized with the gluteal muscles contracted and the erector spinae muscles are developed in their natural relationships to the leg driving force. This usage of the entire chain of the posterior muscles has an absolute effect of improving the posture of the individual.
Accordingly, an object of the present invention is to provide an improved leg-developing device.
Another object of the present invention is to provide a leg-developing device which will exercise and develop the hamstrings, the calf flexors, the quadriceps femoris and the gluteal muscles.
It is still another object of the present invention to provide a leg-developing device which makes possible full leg extension, with adjustable weight resistance so as to bring the hip extensor muscles into the action, only otherwise possible in the natural neuromuscular patterns as may be found in the football line stance position or in the semicrouch position used in track, swimming, wrestling and other sports.
It is a further object of the invention to provide a leg-developing device, as described in the preceding paragraphs, which permits the sequential use and development of the powerful gluteal muscles, brought into play when the trunk is in the fully extended position.
It is a still further object of the invention to provide a device, as described in the foregoing paragraphs, which permits a resistance range of 300 pounds total, 150 pounds for each leg in increments of 10 pounds.
It is a further object of the invention to provide a device, as described in the preceding paragraphs, in which the legs may be extended and exercised either alternately or together against the resistance range as described in the preceding paragraph.
It is a still further object of the invention to provide a device, as described in the previous paragraphs, which eliminates the possibility of knee injuries and low back injuries that occur to a trainee when he is doing low squats with heavy weights. That is, the present invention provides a device in which the benefits of the foregoing exercise with weights may be achieved without the danger of the stated injuries.
Further objects and advantages of the invention may be brought out in the following part of the specification wherein small details have been described for the competence of disclosure, without intending to limit the scope of the invention which is set forth in the appended claims.
Referring to the accompanying drawings, which are for illustrative purposes:
FIG. 1 is a side elevational view of a leg-developing device according to the present invention;
FIG. 2 is a front elevational view of the device shown in FIG. 1, as may be seen looking toward the right from the left side of the latter figure;
FIG. 3 is a plan view of the device shown in FIG. 1;
FIG. 4 is a fragmentary view, partially in cross section, taken as indicated by the line 3--3 in FIG. 1;
FIG. 5 is a fragmentary cross-sectional view, taken as indicated by the line 5--5 in FIG. 3;
FIG. 6 is a fragmentary partially cross-sectional view, taken as indicated by the line 6--6 in FIG. 2; and
FIG. 7 is a fragmentary partially cross-sectional view, taken substantially as indicated by the line 7--7 in FIG. 6.
Referring again to the drawings, there is shown in FIGS. 1-3 a leg developing device, generally designated as 10, comprised of a supporting frame structure, generally designated as 11, and of a pair of parallel guide members or tracks, generally designated as 12 and 13, hingedly secured to the frame at 17.
The frame 11 has a rectangular base, formed of three members 18, 19 and 20. The base members are supported on a horizontal surface 23 and the rear ends of the members 18 and 20 are secured in abutment with a wall 24. Extending upwardly from the base are a pair of vertical support members 25 and 26. Extending horizontally outwardly from the base member 19 are a pair of parallel base extensions 29 and 30, in alignment with the tracks 13 and 12, respectively, and to which the hinge means at 17 is secured.
Inwardly of the upright supports 25 and 26 are a pair of weight-supporting platforms 31 and 32, secured to the base members 18 and 20. Secured to the top of each weight-supporting platform are a pair of coil springs, each designated as 35. Secured to the top of the platform 31 and extending upwardly therefrom are a pair of parallel-spaced channel-shaped bars 36 and 37, the channel openings facing each other as indicated in FIGS. 6 and 7. In the same manner, secured and extending upwardly from the weight platform 32 are a pair of spaced channel-shaped bars 38 and 39.
A set of 15 10-pound weights, generally designated as 42 and 43, surround and are slidably engaged with bars 36, 37 and 38, 39, respectively, the weights being directly supported on the coil springs 35. Each of the weights, as best seen in FIG. 7, has a generally rectangular central opening 44, having a configuration corresponding to that of the two bars 36 and 37 and being such so that the weight can be placed in slidable engagement on the bars only by inserting the weight over an end thereof. Extending outwardly from the central opening 44 is a reentrant portion or slot-shaped opening 47 which extends vertically through the weight. Opposite the opening 47 and extending inwardly from the opening 44 is a cylindrical hole 48.
Slidably engaged in the channels of each pair of bars 36, 37 and 38, 39 is a weight selector bar 49 and 50, respectively, as best seen in FIGS. 2, 6 and 7. Each of the bars 49 and 50 have a plurality of spaced horizontal cylindrical openings 53, adapted to be in register, or to be moved into register with a conveniently adjacent opening 48 in one of the weights. As shown in FIGS. 1, 2 and 6, a selector pin 54 has a handle 55 and a cylindrical pin 56 extending therefrom. The pin extends into the reentrant portion 47, an opening 53 in the selector bar and an opening 48 in the lowest weight, as 42b of a group of weights or of a single weight to be selected for movement upwardly with the selector bar. Thus, as indicated, in FIGS. 1, 2 and 6, when the selector bars 49 and 50 are moved upwardly within the bars 36, 37 and 38, 39, the upper four weights, including 42a and 42b, will be moved therewith. If it is desired to move more or less weights with the selector bars, then the pins 54 must be realigned with an opening 53 in the selector bars which in turn must be properly aligned with an opening 48 in lowest weight desired to be selected.
A lower end 59a of a cable, generally designated as 59, is secured to the top of the selector bar 49 for raising the latter and the weights attached thereto by means of the pin 54 and, similarly, a cable, generally designated as 60, has its lower end 60a secured to the selector bar 50. Each of the cables has upwardly extending portions 59b and 60b between the respective bars 36, 37 and 38, 39, and further extend over a pair of spaced pulleys 61 and 62 mounted on a common axis 63.
The axles of the pulley 61 and 62 are supported on upper horizontal frame members 65 and 66 and a crossmember 67 extending therebetween. A second crossmember 68 joins the inner ends of the members 65 and 66 with the respective upright supports 25, 26. The upper ends of the bars 36, 37 and 38, 39 are also supported and secured on the crossmember 67, and the outer ends of the frame member 65 and 66 are secured in abutment with the wall 24. Extending from the crossmember 68 are a pair of spaced-parallel bars 71 and 72 having their lower ends secured to a cross member 73, shown in FIG. 2, and which is secured to the upright members 25 and 26. On the bar 71 there is a pad 74 for the right shoulder of the trainee and on the bar 72 there is a pad 75 for the left shoulder of the trainee. The lower portions 77 and 78 of the bars 71 and 72 are provided for gripping by the hands of the trainee.
The cables 59 and 60 have portions, as 59c, extending downwardly from the pulleys 61 and 62, and which extend over a second set of pulleys 79 and 81, respectively, on an axis 80, as may be seen in FIGS. 1 and 2. These lower pulleys are supported on the base of the frame. Extending horizontally from the pulleys on the axis 80 are cable portions 59d and 60d and these portions of the cables extend through base extensions 29 and 30 and through the tracks 13 and 12, having their respective ends secured to skates 83 and 84, as may be best seen in FIGS. 4 and 5.
The extensions 29 and 30 are formed of two spaced members having the aforesaid cable portions passing therebetween. The two tracks 12 and 13 are secured together by a crossmember 85, to which the hinge 17 is secured, and an outer crossmember 86.
Each track is formed of a pair of parallel-spaced inwardly opening channel-shaped members as 88, 89 and 90, 91. Each of the channel members forming the tracks has its lower portion, as 94, on the member 88 extending inwardly and upwardly, shown in FIG. 4, to receive the respective wheels 95 of the skates for horizontal travel therein. As may be best seen in FIGS. 3-5, there are stop members 96 and 97 to prevent the movement of the skates toward the frame beyond a point at which further movement thereof would permit the cables to become loose in that the respective weights attached thereto would be at rest and supported on the coil springs 35.
Each of the skates has a horizontal plate member 100 and a forward vertical member 101, secured to the latter and to which the respective cables are secured. A forward portion 102 of the plate 100 provides a support for the toes and forward portion of the foot and extending upwardly at an angle of about 60° is a plate 103 provided to support that part of the foot just rearwardly of the toe portion. The plate 103 is supported by a cylindrical bar member 104, extending between the latter and the plate 100. Extending longitudinally and downwardly from the under side of the plates 100 are a pair of spaced, vertical parallel plates 106 and 107. These plates support the forward and rear axles 108 and 109, respectively, upon which the wheels 95 are mounted.
For operation, the trainee selects the number of 10 pound weights he wishes to exercise his legs and body against by means of the selector pins 54 and as shown in the drawings, 40 pounds of weights will be lifted by the movement of each of the skates away from the frame 11. After the desired number of weights have been selected by the trainee he places his feet upon the skates as previously indicated and his shoulders on the pads 74 and 75, grasping the bar portions 77 and 78 with his right and left hand, respectively. He then may straighten his trunk and extend his legs simultaneously, moving both of the skates away from the frame at the same time. In FIG. 1, the skate 83 is shown in broken lines, having been moved away from the starting point indicated by the stop 96 and the 40 pounds of weights have been lifted as indicated in broken lines. The trainee may also exercise, with his trunk straight, alternately moving one foot away from the frame until the first leg is fully extended, and then commence moving his feet and the respective skates in opposite directions so that the weights attached to one skate will be being lowered and the weights attached to the other skate will be being raised.
When the skates are moved alternately toward and away from the frame, one of the legs is being extended and the other leg is being bent at the knee. During these alternate leg movements the trunk remains in the fully extended position. Therefore, the trunk flexors and extensors are able to stabilize the pelvis in the extended position to provide strong support for the action of the legs. The driving power of the legs is fully utilized with the gluteal muscles contracted and the erector spinae muscles are developed in their natural relationships to the leg driving force.
A removable seat and back rest may be attached to the skates so that the sitting leg press can be accomplished as an accessory leg exercise. When the device is not in use, as shown in FIG. 1, the tracks 12 and 13 may be raised on the hinge and placed vertically against the frame so that the device occupies a relatively small space when not in use.
The invention and its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and arrangement of the parts of the invention without departing from the spirit and scope thereof or sacrificing its material advantages, the arrangement hereinbefore described being merely by way of example. I do not wish to be restricted to the specific forms shown or uses mentioned except as defined in the accompanying claims, wherein various portions have been separated for clarity of reading and not for emphasis.
The invention provides a new principle in leg development work. For the first time, full leg extension may be achieved with adjustable weight resistance whereby the hip extensor muscles may be brought into action in the natural neuromuscular patterns found in the football line stance position and in the semicrouch position used in track, swimming, wrestling and other sports. The extra leg strength derived in the driving action which occurs in the foregoing type of positions, and now which is possible for the first time in a device, according to the invention, induces substantially greater power in the legs so as to provide increased maximal acceleration for all sports.
In the past, all leg press machines used only the leg and thigh muscles with the hips in the flexed position and which did not allow the sequential use and development of the powerful gluteal muscles which are brought into play with the trunk in the fully extended position. In the use of the present invention, the trunk flexors and extensors are able to stabilize the pelvis in the extended position, thereby providing strong support for the action of the legs. The great driving power of the legs is fully utilized with the gluteal muscles contracted and the erector spinae muscles are developed in their natural relationships to the leg driving force. This usage of the entire chain of the posterior muscles has an absolute effect of improving the posture of the individual.
Accordingly, an object of the present invention is to provide an improved leg-developing device.
Another object of the present invention is to provide a leg-developing device which will exercise and develop the hamstrings, the calf flexors, the quadriceps femoris and the gluteal muscles.
It is still another object of the present invention to provide a leg-developing device which makes possible full leg extension, with adjustable weight resistance so as to bring the hip extensor muscles into the action, only otherwise possible in the natural neuromuscular patterns as may be found in the football line stance position or in the semicrouch position used in track, swimming, wrestling and other sports.
It is a further object of the invention to provide a leg-developing device, as described in the preceding paragraphs, which permits the sequential use and development of the powerful gluteal muscles, brought into play when the trunk is in the fully extended position.
It is a still further object of the invention to provide a device, as described in the foregoing paragraphs, which permits a resistance range of 300 pounds total, 150 pounds for each leg in increments of 10 pounds.
It is a further object of the invention to provide a device, as described in the preceding paragraphs, in which the legs may be extended and exercised either alternately or together against the resistance range as described in the preceding paragraph.
It is a still further object of the invention to provide a device, as described in the previous paragraphs, which eliminates the possibility of knee injuries and low back injuries that occur to a trainee when he is doing low squats with heavy weights. That is, the present invention provides a device in which the benefits of the foregoing exercise with weights may be achieved without the danger of the stated injuries.
Further objects and advantages of the invention may be brought out in the following part of the specification wherein small details have been described for the competence of disclosure, without intending to limit the scope of the invention which is set forth in the appended claims.
Referring to the accompanying drawings, which are for illustrative purposes:
FIG. 1 is a side elevational view of a leg-developing device according to the present invention;
FIG. 2 is a front elevational view of the device shown in FIG. 1, as may be seen looking toward the right from the left side of the latter figure;
FIG. 3 is a plan view of the device shown in FIG. 1;
FIG. 4 is a fragmentary view, partially in cross section, taken as indicated by the line 3--3 in FIG. 1;
FIG. 5 is a fragmentary cross-sectional view, taken as indicated by the line 5--5 in FIG. 3;
FIG. 6 is a fragmentary partially cross-sectional view, taken as indicated by the line 6--6 in FIG. 2; and
FIG. 7 is a fragmentary partially cross-sectional view, taken substantially as indicated by the line 7--7 in FIG. 6.
Referring again to the drawings, there is shown in FIGS. 1-3 a leg developing device, generally designated as 10, comprised of a supporting frame structure, generally designated as 11, and of a pair of parallel guide members or tracks, generally designated as 12 and 13, hingedly secured to the frame at 17.
The frame 11 has a rectangular base, formed of three members 18, 19 and 20. The base members are supported on a horizontal surface 23 and the rear ends of the members 18 and 20 are secured in abutment with a wall 24. Extending upwardly from the base are a pair of vertical support members 25 and 26. Extending horizontally outwardly from the base member 19 are a pair of parallel base extensions 29 and 30, in alignment with the tracks 13 and 12, respectively, and to which the hinge means at 17 is secured.
Inwardly of the upright supports 25 and 26 are a pair of weight-supporting platforms 31 and 32, secured to the base members 18 and 20. Secured to the top of each weight-supporting platform are a pair of coil springs, each designated as 35. Secured to the top of the platform 31 and extending upwardly therefrom are a pair of parallel-spaced channel-shaped bars 36 and 37, the channel openings facing each other as indicated in FIGS. 6 and 7. In the same manner, secured and extending upwardly from the weight platform 32 are a pair of spaced channel-shaped bars 38 and 39.
A set of 15 10-pound weights, generally designated as 42 and 43, surround and are slidably engaged with bars 36, 37 and 38, 39, respectively, the weights being directly supported on the coil springs 35. Each of the weights, as best seen in FIG. 7, has a generally rectangular central opening 44, having a configuration corresponding to that of the two bars 36 and 37 and being such so that the weight can be placed in slidable engagement on the bars only by inserting the weight over an end thereof. Extending outwardly from the central opening 44 is a reentrant portion or slot-shaped opening 47 which extends vertically through the weight. Opposite the opening 47 and extending inwardly from the opening 44 is a cylindrical hole 48.
Slidably engaged in the channels of each pair of bars 36, 37 and 38, 39 is a weight selector bar 49 and 50, respectively, as best seen in FIGS. 2, 6 and 7. Each of the bars 49 and 50 have a plurality of spaced horizontal cylindrical openings 53, adapted to be in register, or to be moved into register with a conveniently adjacent opening 48 in one of the weights. As shown in FIGS. 1, 2 and 6, a selector pin 54 has a handle 55 and a cylindrical pin 56 extending therefrom. The pin extends into the reentrant portion 47, an opening 53 in the selector bar and an opening 48 in the lowest weight, as 42b of a group of weights or of a single weight to be selected for movement upwardly with the selector bar. Thus, as indicated, in FIGS. 1, 2 and 6, when the selector bars 49 and 50 are moved upwardly within the bars 36, 37 and 38, 39, the upper four weights, including 42a and 42b, will be moved therewith. If it is desired to move more or less weights with the selector bars, then the pins 54 must be realigned with an opening 53 in the selector bars which in turn must be properly aligned with an opening 48 in lowest weight desired to be selected.
A lower end 59a of a cable, generally designated as 59, is secured to the top of the selector bar 49 for raising the latter and the weights attached thereto by means of the pin 54 and, similarly, a cable, generally designated as 60, has its lower end 60a secured to the selector bar 50. Each of the cables has upwardly extending portions 59b and 60b between the respective bars 36, 37 and 38, 39, and further extend over a pair of spaced pulleys 61 and 62 mounted on a common axis 63.
The axles of the pulley 61 and 62 are supported on upper horizontal frame members 65 and 66 and a crossmember 67 extending therebetween. A second crossmember 68 joins the inner ends of the members 65 and 66 with the respective upright supports 25, 26. The upper ends of the bars 36, 37 and 38, 39 are also supported and secured on the crossmember 67, and the outer ends of the frame member 65 and 66 are secured in abutment with the wall 24. Extending from the crossmember 68 are a pair of spaced-parallel bars 71 and 72 having their lower ends secured to a cross member 73, shown in FIG. 2, and which is secured to the upright members 25 and 26. On the bar 71 there is a pad 74 for the right shoulder of the trainee and on the bar 72 there is a pad 75 for the left shoulder of the trainee. The lower portions 77 and 78 of the bars 71 and 72 are provided for gripping by the hands of the trainee.
The cables 59 and 60 have portions, as 59c, extending downwardly from the pulleys 61 and 62, and which extend over a second set of pulleys 79 and 81, respectively, on an axis 80, as may be seen in FIGS. 1 and 2. These lower pulleys are supported on the base of the frame. Extending horizontally from the pulleys on the axis 80 are cable portions 59d and 60d and these portions of the cables extend through base extensions 29 and 30 and through the tracks 13 and 12, having their respective ends secured to skates 83 and 84, as may be best seen in FIGS. 4 and 5.
The extensions 29 and 30 are formed of two spaced members having the aforesaid cable portions passing therebetween. The two tracks 12 and 13 are secured together by a crossmember 85, to which the hinge 17 is secured, and an outer crossmember 86.
Each track is formed of a pair of parallel-spaced inwardly opening channel-shaped members as 88, 89 and 90, 91. Each of the channel members forming the tracks has its lower portion, as 94, on the member 88 extending inwardly and upwardly, shown in FIG. 4, to receive the respective wheels 95 of the skates for horizontal travel therein. As may be best seen in FIGS. 3-5, there are stop members 96 and 97 to prevent the movement of the skates toward the frame beyond a point at which further movement thereof would permit the cables to become loose in that the respective weights attached thereto would be at rest and supported on the coil springs 35.
Each of the skates has a horizontal plate member 100 and a forward vertical member 101, secured to the latter and to which the respective cables are secured. A forward portion 102 of the plate 100 provides a support for the toes and forward portion of the foot and extending upwardly at an angle of about 60° is a plate 103 provided to support that part of the foot just rearwardly of the toe portion. The plate 103 is supported by a cylindrical bar member 104, extending between the latter and the plate 100. Extending longitudinally and downwardly from the under side of the plates 100 are a pair of spaced, vertical parallel plates 106 and 107. These plates support the forward and rear axles 108 and 109, respectively, upon which the wheels 95 are mounted.
For operation, the trainee selects the number of 10 pound weights he wishes to exercise his legs and body against by means of the selector pins 54 and as shown in the drawings, 40 pounds of weights will be lifted by the movement of each of the skates away from the frame 11. After the desired number of weights have been selected by the trainee he places his feet upon the skates as previously indicated and his shoulders on the pads 74 and 75, grasping the bar portions 77 and 78 with his right and left hand, respectively. He then may straighten his trunk and extend his legs simultaneously, moving both of the skates away from the frame at the same time. In FIG. 1, the skate 83 is shown in broken lines, having been moved away from the starting point indicated by the stop 96 and the 40 pounds of weights have been lifted as indicated in broken lines. The trainee may also exercise, with his trunk straight, alternately moving one foot away from the frame until the first leg is fully extended, and then commence moving his feet and the respective skates in opposite directions so that the weights attached to one skate will be being lowered and the weights attached to the other skate will be being raised.
When the skates are moved alternately toward and away from the frame, one of the legs is being extended and the other leg is being bent at the knee. During these alternate leg movements the trunk remains in the fully extended position. Therefore, the trunk flexors and extensors are able to stabilize the pelvis in the extended position to provide strong support for the action of the legs. The driving power of the legs is fully utilized with the gluteal muscles contracted and the erector spinae muscles are developed in their natural relationships to the leg driving force.
A removable seat and back rest may be attached to the skates so that the sitting leg press can be accomplished as an accessory leg exercise. When the device is not in use, as shown in FIG. 1, the tracks 12 and 13 may be raised on the hinge and placed vertically against the frame so that the device occupies a relatively small space when not in use.
The invention and its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and arrangement of the parts of the invention without departing from the spirit and scope thereof or sacrificing its material advantages, the arrangement hereinbefore described being merely by way of example. I do not wish to be restricted to the specific forms shown or uses mentioned except as defined in the accompanying claims, wherein various portions have been separated for clarity of reading and not for emphasis.