US 3156318 A
Description (OCR text may contain errors)
1954 B. w. SORENSON ETAL 3,156,318
ROLLER STAND FOR TRAMPOLINES Filed Feb. 15, 1962 2 Sheets-Sheet 1 I //v VENTORS' 4 -44 k B/LL W. .SORENSON 9 10 By CARL DEN/M2071 damflgggg;
B. w. SORENSON ETAL 3,156,318
' ROLLER smn FOR TRAMPOLINES Filed Feb. ;5, 1962 2 Sheets-Sheet 2 lNl/ENTORS B/u. M 50/?EN5 0N By CARL DENHARDT United States Patent 3,156,318 RQLLER STAND FER TRAMPGLINES Bill W. Sorenson and Carl Denhardt, Jefferson, Iowa, assignors to American Trampoline Company, Jefferson, Iowa, a corporation of Iowa Filed Feb. 15, 1962, Ser. No. 173,480 3 Claims. (Cl. 182-139) The larger trampolines which are commonly used in competitive trampoline events normally have an erected horizontal frame which is rectangular in shape and which is supported on oppositely disposed U-shaped legs that are pivotally secured to the frame. Because of the large size of these erected trampoline frames, it is necessary to have them of foldable construction so that they can be collapsed for storage, shipment, or movement from one place to another in the gymnasium. Obviously, such a frame is pivoted at the third points on the lateral edges thereof so that the frame can be folded upon itself into three sections. A vertical roller stand of fixed dimensions is pivotally secured to the center of each side of the middle frame section whereupon the three folded frame sections can be pivoted into a vertical position and the entire trampoline can then be supported on the two roller stands.
The roller stands are normally supported on a floor surface by caster elements, and the overall height of the roller stands provides a sumcient degree of clearance between the floor and the folded trampoline frame to permit the frame to be unfolded and the legs thereof erected without the floor surface interfering in any of these operations. However, the height at which the roller stands must hold a folded trampoline in order to accomplish these operations often prevents the passage of the suspended trampoline through conventional door openings. When the vertical height of a folded trampoline suspended on conventional roller stands will not ne otiate a door opening, it is necessary to completely remove the roller stands and then to laboriously slide the heavy trampoline over the floor surface and through the door opening. This burdensome task is time consuming and involves the efforts of several people. It also invites damage to the floor surface and door opening, and there is obviously some hazard involved in manually sliding a trampoline weighing many hundreds of pounds through a narrow passageway.
Therefore, the principal object of our invention is to provide a roller stand for trampolines that can have its vertical height adjusted.
A further object of our invention is to provide a roller stand for trampolines that is capable of lifting a folded trampoline back to its normal position after the height of the roller stand has been adjusted to a lower position.
A still further object of our invention is to provide a roller stand for trampolines that can be selectively actuated to hold a trampoline in a lower position for any desired period of time.
A still further object of our invention is to provide a roller stand for trampolines that'will permit the selective manual lowering of atrampoline without utilizing manual in the art.
Our invention consists in the construction, arrangements, andcombination, of the various parts of the device,
whereby the objects contemplated are attained as hereinafter more fully set forth, specifically pointed out in our claims, and illustrated in the accompanying drawings, in which:
FIG. 1 is a perspective view of a folded trampoline mounted on a pair of our roller stands;
FIG. 2 is a partial elevational view of a trampoline frame showing the socket into which our roller stand fits to support the frame;
FIG. 3 is a plan view of that portion of the trampoline frame shown in FIG. 2 with one of our roller stands positioned for immediate attachment to the frame;
FIG. 4 is a perspective view of one form of our device with portions thereof cut away to more fully illustrate its construction;
FIG. 5 is a sectional view of our device taken on line 5-5 of FIG. 4;
FIG. 6 is a partial perspective view of another form of our device showing the lock structure used on both forms of our device;
PEG. 7 is a partial front elevational view of the lock structure shown in FIG. 6 in an unlocked position;
FIG. 8 is a partial side elevational view of the lock structure shown in FIG. 7 as the trampoline frame is being lowered and is about to be locked;
FIG. 9 is a view similar to that of FIG. 8 except the lock structure is in .its locked position; and
FIG. 10 is a side elevational view of an erected trampoiine. I
With reference to FIGS. 1 and If}, we have used the numeral 10 to generally designate a trampoline. End frame sections 12 are pivotally secured to center frame section 14 by hinges 16. U-shaped leg sections 18 are pivotally secured to the frame sections in any convenient manner and chains Zil extend between the leg sections and the center frame section M to limit the pivotal movement of the leg sections. End braces 22 detachahly connect the lower portions of the leg sections 1'8 to the outer ends of end frame sections 12. As shown in FIG. 3, a hanger bar 24 can be welded to the inside periphery of each of the frame sections. Resilient loops as comprised of shock cord are disposed in elongated positions and are secured byone of their ends to bed 23 and are secured by their other ends to hangerbar 24 by means of clips 3ft.
As shown in FIG. 2, center frame section 14 is cornprised of at least one top rail 32 with a lower V-shaped rail 34 secured thereunder so that the lowermost portion of rail 34 is in spaced relation to the rail 32. A horizontal sleeve or socket 35 is welded or otherwise secured to the center of frame section 14 at a point between the two rails 32 and 34. Our roller stands are normally inserted into these sleeves 36 on opposite sides of the trampoline frame.
We shall first describe the roller stand shown in FIG. 4.
1 A horizontally disposed stud shaft 38 is welded or other- Tube 42 is welded by its lower end to horizontal cross bar 44. Caster elements 46 including wheels 43 are secured v to and extend downwardly from the lower end portions of the cross bar 44- whereupon the wheels 43 are adapted to engage a supporting surface.
Tube 40 is circular in cross secv tion and slidably receives hollow tube 4-2 in its lower end.
A horizontally disposed 'i-shaped bracket St: is welded to the lower end of tube 40 to extend therefrom in the same direction as shaft 33. Bracket 59 serves to engage a folded trampoline frame supported on a pair of roller stands to prevent the inadvertent pivoting of the trampoline frame on the stud shafts 38. Bracket 50 is also sometimes used as a gripping point to exert leverage on the roller stand.
Vertical slots 52 appear in opposite sides of tube 40 near its lower end. Lugs d are rigidly secured to tube 42 and extend radially outwardly therefrom through each of the slots A coil spring 55 extends from the bottom interior end of tube 4-2 to the upper interior end of tube 4%. Spring 5 is in its expanded con ition and supports tube 40 in an elevated position with respect to tube 42. This spring should have sufficient strength to completely resist a compressive force equal to only a few pounds more than half the weight of the trampoline to be supported so that a trampoline being supported by a pair of our roller stands will at least be held in the elevated position shown by tube 49 in FIG. 1. Lugs 54 and slots 52 serve to prevent tube 46* from turning on tubes 42, and these elements also prevent tube 4% from being removed from tube 42 when the unloaded roller stands are being handled.
The form of our invention shown in FIG. 6 is similar to that shown in H6. 4 except that hollow square tubes 46A and 42A are used in place of tubes 48 and 42, respectively. A flexible chain 5'8 is welded by its ends to tubes 49A and 42A to prevent the inadvertent separation thereof. All other component parts of the form of our invention shown in MG. 6 are identical to corresponding parts in the device shown in FIG. 4.
A locking means d9 includes a horizontally disposed U-shaped bracket 52 which is welded by the ends of its two legs to the lower portion of tubes 42 and 42A on the side of the roller stand opposite to the direction of extension of stud shaft 38. A conventional nut 64 is welded to tubes or 42A within bracket 62 so that the threaded bore thereof (not shown) extends outwardly from the tube in a horizontal direction. A bolt es extends through a suitable aperture in bracket 62 and is threadedly received by its inner end in the threaded bore of nut S4. A vertically disposed finger as is loosely mounted on bolt 66 within bracket 62 by means of the bolt extending through a suitable enlarged aperture (not shown) therein near the center of the finger. An inwardly extending hook portion '76 appears on the upper end of finger 68. Block portion 7% is adapted to catch on lug 72 which is mounted on the lower ends of both tubes 49 and 40A. Lugs '72 have a horizontal top surface and a lower tapered cam surface 7d. A spring 73 encompasses bolt 65 and normally urges hook portion in of finger 68 into engagement with tube 42 or 42A.
The normal operation of our device is as follows: As indicated above, the stud shafts 38 on a pair of roller stands are inserted into the sockets 36 on opposite sides of the trampoline frame. The vertical height of the roller stands is greater than the vertical height of the socket 35 on the erected trampoline in FIG. l0. Thus, the roller stands initially assume the inclined position shown by the dotted lines in FIG. 10. Usually, the erected trampoline is manually held against movement, and pressure is exerted by the foot on the roller stands to move them to a vertical position whereby the entire trampoline can be lifted by the stands and held in spaced relation to the supporting surface. T he trampoline is then collapsed and folded into the position shown in FAG. 1. The manner in which the trampoline is actually mounted on the roller stands does not constitute a part of our invention and, obviously, this operation can vary considerably in its sequential steps.
With the trampoline in the suspended and elevated position shown PEG. 1, the trampoline can be readily moved by merely pushing it in the desired direction on the four supporting wheels 43. Since the springs 56 in the two roller stands have a combined resistance to compression which is slightly greater than the total weight of the trampoline, the tube (and 49A) will not move downwardly on tube 42 (and 42A) to lower the overall height of the folded trampoline. However, when a door opening is encountered that will not provide sufiicient vertical clearance for the trampoline, a slight manual pressure can be applied downwardly 0n tubes 46 (or 4tlA) which will overcome the springs 56 and cause them to compress. The compression of springs 56 allows the tube 4%) (and MBA) to slide downwardly on tubes 42- (and 42A) to lower the effective vertical height of the folded trampoline. As tube 46 (or itlA) moves downwardly, the lug 7'2 on the lower thereof engages and catches the hook portion 70 on finger 6?; of locking means 60. This sequential action is shown in FIGS. 8 and 9. The engagement and locking of finger 68 on lug '72 will hold the trampoline in this lowered position as it is moved through the low door opening. After the door opening has been negotiated, pressure can be applied to the lower end of finger 63, as viewed in FIG. 9, and fin er 68 will pivot out of engagement with lug 7'2 whereupon the springs 56 will expand and lift the trampoline to its initial elevated position at which it must be maintained to be successfully unfolded.
Thus, from the foregoing, it is seen that our device will accomplish at least all of its stated objectives.
Some changes may be made in the construction and arrangement of our roller "tand for trampolines without departing from the real spi it and purpose of our invention, and it is our intention to cover by our claims, any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope.
1. In a trampoline, comprising,
a trampoline frame being substantially rectangular in size,
support means at each end of said frame for supporting said frame when said trampoline is in an extended horizontal position,
a roller stand on each side of said frame intermediate the ends thereof, said roller stand having a pair of telescoping members, a spring means interconnecting said members to normally extend them relative to each other, one of said members having means for pivotally engaging the frame of said trampoline, the other of said members having a cross bar on its lower end, and roller means on said cross bar at each end thereof for engagement with a supporting surface,
means for limiting relative extension and rotation between said telescoping members,
the combined strength of said spring means in each roller stand being sufficient to extend each pair of telescoping members to a length sufiicient to support said trampoline above the supporting surface when each of said roller stands is in a vertical position extending between the trampoline frame and the supporting surface, and
said roller stand adapted to pivot on said trampoline frame to a position extending at an acute angle to said trampoline frame with said spring means extending said pair of telescoping members to give said roller stand a length greater than the vertical distance between the trampoline frame when in its extended horizontal position and the supporting surface, said roller stand when in said last mentioned position having only one of said roller means on said cross bar in engagement with said supporting surface, said spring means being compressed to reduce the overall length of said roller stand as said roller stand is pivoted to a vertical position to return said roller means on the other end of said cross bar into engagement with said supporting surface.
2. The trampoline of claim 1 and means for locking said telescoping members in a retracted position against the action of said spring means tending to extend them relative to each other.
3. The trampoline of claim 1 wherein said means for limiting relative extension and rotation between said telescoping members includes one of said pair of telescoping members having an elongated recess formed therein and disposed in a plane parallel to the longitudinal axis of said pair of telescoping members and the other telescoping member having a pin means secured thereto and received in said recess for movement between opposite ends of said recess as said telescoping members are moved longitudinally relative to each other.
References Cited by the Examiner UNITED STATES PATENTS Hall 182-24 Biedermann 248409 Stoll 248-408 Flogaus 248408 Becker 287-58 Fenner 182-139 Morrell 248-356 HARRISON R. MOSELEY, Primary Examiner. S. L. BREHM, Examiner.