US3090578A

US3090578A - Spring counterbalance mechanism

Info

Publication number: US3090578A
Application number: US115360A
Authority: US
Inventors: Eugene T Olson
Original assignee: Individual
Current assignee: Individual
Priority date: 1961-06-07
Filing date: 1961-06-07
Publication date: 1963-05-21
Anticipated expiration: 1980-05-21

Description

May 21, 1963 E. T. OLSON SPRING COUNTERBALANCE MECHANISM Filed June 7, 1961 FIE.

INVENTOR.

irroawar United States Patent 3,090,578 PRING COUNTERBALANCE MECHANISR i Eugene T. Olson, 2905 Lincoln NE, Minneapolis, Minn- Filed June 7, 1961, Ser. No. 115,360 3 Claims. (l. 242-107.5)

This invention relates to counterbalances and more particularly to a spring counterbalance mechanism.

Some forms of counterbalance units incorporate a tension spring which permits only a limited distance of movement for the weight being counterbalanced. Others incorporate a recoil spring which allows uneven counterbalance tension throughout the travel distance of the weight. Still others incorporate a flexible cable as the tie means between the weight being counterbalanced and the counterbalance unit itself. Cables very often cause undesirable twisting torque of the reel it is wound upon as well as of the housing.

In addition to the undesirable twisting torque often associated with a cable, there is often undesirable uneven winding of the cable upon the counterbalance reel which may cause the cable to ultimately slide off of the reel surface.

It is to the elimination of the above mentioned undesirable features of counterbalances which the present invention is intended to overcome. Accordingly:

An object of this invention is to provide a counterbalance having structure and components which clumnate twisting side torques;

Another object of this invention is to provide a device of the class described which is so constructed and arranged that the variations in tension of the counterbalance will be minimized;

A further object of this invention is to provide adjustability for counterbalances of difierent weights without changing of counterbalance units;

A still further object is to provide a reel having braces which stabilize the reel against twisting in addition to providing a guide for the weight strap, and other desirable features;

A further object is to provide a counterbalance which stresses simplicity of design and construction, and which lends itself easily to construction and repair.

These and other objects and advantages of the invention will more fully appear from the following description, made in connection with the accompanying drawing, wherein like reference characters refer to the same or similar parts throughout the several views and in which:

FIGURE 1 is a perspective view of a counterbalance shown as it would be positioned on a frame (shown in phantom drawing), and a typical weight secured thereto (also in fantom drawing);

FIGURE 2 is an enlarged top view of FIGURE 1;

FIGURE 3 is an enlarged cross-sectional side view of FIGURE 2 taken on line 3-3;

FIGURE 4 is a partial cross-sectional view of FIGURE 3 taken on line 44; and

FIGURE 5 is an enlarged perspective view of a brace as it appears on the reel discs (shown in phantom drawin Referring particularly to FIGURES 1 and 2, a weight 9, typified by a block and which requires counterbalancing, is supported by a spring counterbalance referred to generally as which has a partially enclosing housing or cover 11, made from sheet material, which has formed as a part thereof its own mounting feet 12. Mounting feet 12 in turn have mounting holes 13 for securement of the housing to a frame 14.

Shown mounted across the housing, in FIGURE 2,

is a bolt or shaft 15 having a head 16 adapted to be held ass sts Patented May 21, 1963 by a wrench. Between the head 16 and housing 11 is a washer 17. Secured upon the threaded portion 18 of shaft 15 is a nut 19 which is in turn welded at 20 to a tension lever 21. Again a washer 22 is interposed between the tension lever 21 and housing 11. It may be pointed out at this time that the threaded portion 18 extends only to the washer 22 so that when the nut 19 is engaged upon the threaded portion 18 to the end of the threads, further engagement of the nut will be prevented thus causing the shaft 15 to rotate. It is this feature which allows the shaft 15 to be rotated and accordingly the recoil spring tension adjusted, as will be explained subsequently.

To prevent reverse rotation of the tension lever 21 when it is under tension, a tension tie 23 is provided which is simply a band of sheet metal, or similar structure, secured at ends 24 by a bolt and nut combination 25 to the housing 11.

Referring now to FIGURES 3 and 4, the internal construction of the counterbalance 10 will be explained. Rotatably secured to the shaft 15 by means of bearings 26 is a reel 27. The reel in turn has a pair of reel discs 28, which are secured to the bearings 26, and a plurality of continuous brace structures 29 which define a substantially circularly oriented supporting edge referred to generally as.30, around the periphery of the reel discs 28. The supporting edge is defined by the channel area 31 of the braces 29 (see FIGURE 4).

Noting FIGURES 4 and 5 particularly, the braces 29 consist of a supporting mid-portion 32 which is radially recessed with respect to the humps 33 located at either end thereof. Humps 33 have a reverse bend 34 Which interfits with the outer peripheral edge 35 of the reel discs 28. Continuous with .the humps 33 are mounting ends 36 which are welded at 37 to the reel discs for positive securement thereto.

As seen in FIGURES 3 and 4, the braces 29 and reel discs 28 define an open space 38 within which a recoil spring 39 is located and confined. It is found that when a recoil spring of steel tape, of considerable stiffness, is used, an optimum recoil characteristic is achieved which allows substantially even tension on the reel 27 when the reel is actuated. Because of this type of material used, the recoil spring 39 will have a tendency to expand outwardly and therefore rides on the inner pheriphery surface 40 of the supporting edge 30. The recoil spring, of course, is radially confined by the braces 29. The outer end 41 of the recoil spring 39- is hooked about a brace for securement to the reel. The inner end 42 is secured to the shaft 15 by means of an anchor system 43.

The anchor system consists of a pair of anchor plates or discs 44 which have holes 45 for interfi-tting with the shaft 15. Welded between the anchor plates, and thereto, is an anchor nut 46. Threaded through the nut and in engagement therewith is an anchor bolt 47 which is also projecting through the shaft 15, as seen in FIGURE 4. The purpose of projecting anchor bolt 47 through the shaft is to prevent relative rotational movement between the shaft and anchor system 43. Also forming a part of the anchor system is an anchor washer 48 which is drawn into clamping contact with the inner end 42 of the recoil spring 39 for securement thereto. Inner end 42 also has a hole therethrough which anchor bolt 47 projects through.

Shown wound upon the supporting edge 39 of the reel is a weight strap 49 which is secured by a hook means 50 at the inner end thereof to an anchor pin 51. The anchor pin in turn is secured across the reel discs and protrudes therethrough for positive securement thereof. The outer end of the weight strap is shown as it is protruding exteriorly of the housing for mounting to a weight.

It will be noted at this time that the recoil spring 39 extends substantially the width of the inside dimension between reel discs 28. With this maximumwidth of the recoil spring, an optimum spring characteristic may be attained. In addition there is even radial force on the supporting edge 30 and, therefore, the recoil spring exerts no twisting torque upon the reel mechanism. The weight strap 49 is also substantially the width of the channel 31. Again, by providing a wide weight strap, twisting torques are eliminated.

In the assembly of the counterbalance, a recoil spring is secured at its inner end 42 to the anchor assembly 43. The tension lever 21 is then rotated whereby to cause the recoil spring to 'be drawn or reeled into the open space 38. During this assembly, the reel is held stationary and the recoil spring is caused to feed between braces 29 into the open space 38. When the outer end 41 of the recoil spring is drawn into the open space 38, it is then hooked to any one of the braces 29 as shown in FIGURE 3.

With the recoil spring installed, the weight strap 49 then has the inner end thereof hooked upon the anchor pin 51 and, by continued rotation of the tension lever, has the full travel length of the weight strap wound upon the supporting edge. At this point the tension lever is locked in position by the tension tie 23. It is now seen that any unreeling of the weight strap will cause increasing tension on the recoil spring, and consequently upon the reel 27 and strap 49. If increased tension is desired on the weight strap, the tension lever may be wound additional turns while holding the protruding end of the weight strap stationary.

Accordingly then, a counterbalance is provided which has no twisting torque associated therewith and, because of the components incorporated, has a substantially even tension on the weight strap through the contemplated amount of run-out thereof. In addition, this simple design lends the counterbalance to ready adjustment for different weights without changing counterbalance units. Also, by incorporating braces secured across the reel A the outer edges of said reel discs whereby said discs and said braces define an open space between said shaft and said braces, an anchor pin secured across said reel discs adjacent the outer edges thereof, a stiff but flexible metal weight strap wound externally upon said braces having one end secured to said anchor pin and the other end protruding exteriorly of said housing in a free end adapted for attachment to a substantially heavy weight, and a stiff but flexible recoil spring wound about said shaft and secured at one end thereto and at the other end to one of said braces, said recoil spring further being confined to said open space and further having a width substantially the distance between said reel discs.

2. A spring counterbalance as set forth in claim 1 wherein said braces comprise a continuous supporting midportion extending the distance between said reel discs, a hump formed at both ends of said mid-portion and interfitted with the outer edges of said reel discs, and mounting ends secured to said reel discs at the outer ends of said humps, whereby said supporting mid-portion is radially recessed from said humps whereby to form a channel for seating of said weight strap.

3. A spring counterbalance comprising, a housing adapted to be mounted to a frame structure, a shaft mounted across said housing, a reel rotatably secured on said shaft having two substantially circular reel discs secured in spaced parallel relation to said shaft by means of a pair of bearings, said reel also having a plurality of flat and narrow braces secured across the outer edges of said reel discs whereby said discs and said braces define an open confinement between said shaft and said braces, said braces also having a radially recessed supporting midportion when positioned across the outer edges of said discs, an anchorpin secured across said reel discs adjacent the outer edges thereof but within said open confinement, a stiif but flexible metal strap wound externally upon said braces within said radially recessed portion, said strap having one end secured to said anchor pin and the other discs, an additional stabilizing effect is achieved while at :the same time providing a channel guiding means for the winding and unwinding of the weight strap.

It will, of course, be understood that various changes may bemade in the form, details, arrangements and proportions of the parts without departing from the scope of my invention as set forth in the appended claims.

What is claimed is:

1. A spring counterbalance comprising, a housing adapted to be mounted to a frame structure, a shaft mounted across said housing, a reel rotatably secured on said shaft and having two similar and substantially circular reel discs secured in spaced relation on said shaft and a plurality of flat and narrow braces secured across end'protruding exteriorly of said housing in a free end adapted for attachment to a substantially heavy weight, and a stiff but flexible recoil spring wound about said shaft and secured at one end thereto and at the other end to one of said braces, said recoil spring further being confined to said open space and further having a width substantially the distance between said reel discs.

References Cited in the file of this patent UNITED STATES PATENTS 116,108 Sterns June 20, 1871 511,655 Small et al Dec. 26, 1893 532,130 Woodward et al. Jan. 8, 1895 681,864 Wallace'et al; Sept. 3, 1901 1,105,680 Mitchell, Aug. 4, 1914- I,679,573 Hind Aug. 7, 1928 1,795,529 Watson et al. Mar. 10, 1931

Claims

1. A SPRING COUNTERBALANCE COMPRISING, A HOUSING ADAPTED TO BE MOUNTED TO A FRAME STRUCTURE, A SHAFT MOUNTED ACROSS SAID HOUSING, A REEL ROTATABLY SECURED ON SAID SHAFT AND HAVING TWO SIMILAR AND SUBSTANTIALLY CIRCULAR REEL DISCS SECURED IN SPACED RELATION ON SAID SHAFT AND A PLURALITY OF FLAT AND NARROW BRACES SECURED ACROSS THE OTHER EDGES OF SAID REEL DISCS WHEREBY SAID DISCS AND SAID BRACES DEFINE AN OPEN SPACE BETWEEN SAID SHAFT AND SAID BRACES, AN ANCHOR PIN SECURED ACROSS SAID REEL DISCS ADJACENT THE OUTER EDGES THEREOF, A STIFF BUT FLEXIBLE METAL WEIGHT STRAP WOUND EXTERNALLY UPON SAID BRACES HAVING ONE END SECURED TO SAID ANCHOR PIN AND THE OTHER END PROTRUDING EXTERIORLY OF SAID HOUSING IN A FREE END ADAPTED FOR ATTACHMENT TO A SUBSTANTIALLY HEAVY WEIGHT, AND A STIFF BUT FLEXIBLE RECOIL SPRING WOUND ABOUT SAID SHAFT AND SECURED AT ONE END THERETO AND AT THE OTHER END TO ONE OF SAID BRACES, SAID RECOIL SPRING FURTHER BEING CONFINED TO SAID OPEN SPACE AND FURTHER HAVING A WIDTH SUBSTANTIALLY THE DISTANCE BETWEEN SAID REEL DISCS.