Title:
Steel beam or spring
United States Patent 2058076


Abstract:
This invention relates to a flexible or resilient steel beam which may be employed as a spring or for other purposes. Customarily, laminated steel springs are made of a number of different length cambered plates of steel having their centers secured by a clamp or buckle, the plates being arranged...



Inventors:
Thomson, Glascodine Richard
Application Number:
US75197634A
Publication Date:
10/20/1936
Filing Date:
11/08/1934
Assignee:
Thomson, Glascodine Richard
Primary Class:
Other Classes:
52/636, 267/47, 267/165
International Classes:
F16F1/18
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Description:

This invention relates to a flexible or resilient steel beam which may be employed as a spring or for other purposes.

Customarily, laminated steel springs are made of a number of different length cambered plates of steel having their centers secured by a clamp or buckle, the plates being arranged with their flat faces towards the direction of force and each plate giving the spring some additional strength, the total strength of the spring being the sum of the strengths of the several plates.

For example, a spring comprising eight plates 4" wide and 12" thick is equivalent in strength to one plate 8x4=32" wide and /2" thick giving a strength proportional to the modulus of the section obtained by the formula B D2 6 where B is the width and D is the depth of the plate. In this case the indicative figure is 32XV 6 In contradistinction to the usual arrangement of the plates with their flat faces towards the 2direction of force, beams or springs according to the invention consist of a plurality of plates assembled with their edges towards the direction of force and so would differ in function from ordinary springs in that they would give little movement but would offer high pressures and would be useful in circumstances where, at present, ordinary springs giving much movement cannot be used.

Assuming a beam according to this invention to be employed as a spring, and having the dimensions quoted in the aforementioned example, i. e. one of eight plates 4" wide and ½" thick arranged with their edges towards the direction of force according to the invention, the spring would have a modulus of 4X42 - =10.66, as against 1.3 with the usual disposition. The small amount of movement characterizing the assembly of plates according to the invention enables it to be employed as a resilient beam, and it will be appreciated that if instead of a beam made of forged or cast metal having the stiffness and limited strength of such material, a resilient beam is made up of relatively thin spring tempered plates, the stress to which it can be safely subjected is greatly increased and 04 consequently a much smaller and lighter section can be used than would otherwise be possible to carry a given load. In the case of forgedmetal, the yield point is in the neighborhood of 16 tons to the square inch, whereas with spring tempered plates the yield point is about four or five times this figure, there being the additional advantage, where the beam is employed as an element of a shock cushioning device, such for instance as buffing and draft gear as described in co-pending application Serial No. 751,975 that the limited movement which takes place under heavy stress greatly reduces the danger of crystallization and resultant fracture in the adjacent parts of the vehicle structure.

The cheapness with which spring beams according to the invention may be manufactured will be apparent, since they may be cut straight sided from a length of plate steel and the expensive smithwork of cambering or setting necessary with laminated steel springs as at present constructed, is avoided.

The plates embodied in the spring advantageously comprise lengths of spring steel of flat triangular shape, with the apex removed to provide a flat seat, clamped together at their center by means of a bolt or bolts or in other appropriate manner, bolts or hardened ferrules being advantageously employed to unite the adjacent plates at their ends to form suitable bearings for shackle or like pins.

Slippers or stools may be employed on the ends of the spring to make them proud of the centre portion and provide the equivalent of camber in the event of the effecting force being provided by a flat beam or abutment.

By compounding springs according to the embodiment described, i. e. uniting two springs each consisting of an assembly of flat triangular plates with their alternate bases opposed, double movement could be obtained without increase in overall length or depth, and it will be appreciated that the operation of the springs could be otherwise varied, for instance by means of anchors or clamps between the centre and ends thereof exerting pressure producing friction between adjacent plates so as to increase the resistance to movement and reduce the power of recoil. Similarly, between adjacent spring plates of a single or compound spring intermediate friction plates of steel or other appropriate material could be employed.

The invention will be further described with reference to the accompanying drawings which illustrate diagrammatically several embodiments, and in which drawings,Fig. 1 is a perspective view of a resilient beam especially suited for use in the buffing and draft gear according to the aforementioned co-pending application Serial No. 751,975.

Figs. 2 and 3 are respectively a plan and front elevation of a quasi triangular form of beam, Fig. 4 being a perspective view of a compounded triangular spring beam affording double movement without material increase in overall length or depth.

Figs. 5 and 6 are respectively a plan and front elevation of an alternative form of compounded beam affording double movement and suitable for use in cases where additional space is available.

Fig. 7 is a diagrammatic showing of central buffing and draft gear employing a pair of resilient beams similar to that illustrated in Figs. 2 and 3.

Referring now to the drawings but first more particularly to Fig. 1, the resilient beam comprises six facsimile laminated flat plates 1-6 of spring tempered material, preferably spring steel, clamped together at each end by means of stool clips 7 and 8 through which are passed ferrules or rivets 9 and 10, and at the centre by a stool clip 11 through which is passed a ferrule or rivet 12.

In this embodiment, the plates are rectangular in form and are clamped together by the stool clips in such a manner that the opposed faces of adjacent plates are in contact over their whole area, any relative movement between the plates being therefore frictionally resisted as well as prevented by the ferrules 9 and 10.

The arrows indicate the direction in which the forces will be applied when the beam is in use, for instance as a cross member in the buffing and draft gear described in co-pending application Serial No. 751,975 where it serves to operate the outside springs of the gear, and it will be appreciated that in contradistinction to the customary leaf spring where the forces to which the spring is subject or which the spring is intended to cushion are at right angles to the planes containing the surfaces of the individual plates of the spring, with the beam according to the present invention the forces, as indicated by the arrows, are applied edgewise of the plates, i. e. in a plane parallel to the planes containing their surfaces.

Consequently, instead of a strength proportional to the modulus of the section obtained by the formula as aforementioned, where the plates are 4" wide and 1" deep equivalent to 1 in the case of the ordinary leaf spring arrangement, an indicative 60 figure of 8 is obtained for the beam illustrated, it being further differentiated from a leaf spring in the small, it may be infinitesimal, amount of movement which takes place even under heavy pressures. It will be appreciated that the stress 65 to which a resilient beam made up of relatively thin spring tempered plates can be subjected safely is considerably greater than that capable of being accommodated by a beam made of forged 70 or cast metal having the stiffness and limited strength of such material.

The following table showing the respective deflections of an ordinary steel beam and a similar sized beam made up of three spring plates under 75 the same conditions of transverse loading clearly Total deflection thousandths of an inch Load in tons Ordinary Three plate beam spring beam 1 0 0 10 11 7 20 23 12 30 35 23 40 59 35 42.5 103 45 167 41 47.5 229 50 306 46 60 -----..... 58 70 - . . 70 80 ---------. 82 90 .-- -- -- -- 94 100 -----.-... 107 As will be seen, the ordinary beam commences to yield considerably and in fact is in collapse at 40 tons, while on the other hand the deflection-load graph of the spring beam obtained from the test figures shows a straight line from 25 20-100 tons, beyond which the test was not continued.

In the alternative embodiment illustrated in Figs. 2 and 3, in place of the laminated plates being of simple rectangular section a quasi tri- 30 angular section providing maximum utilization is employed, the end stool clips 7 and 8 and the centre clip I1, with their attendant ferrules 9, 10 and 12, being similar to those employed in the preceding Figure 1, the plates having sloping 35 shoulders 14 and 15, and consequently being so shaped that the material thereof is stressed substantially uniformly along the length of the beam by the forces applied.

A second ferrule 16 assists the ferrule 12 in se- 40 curing the centre portions of the six plates together, the width of the plates at this portion being somewhat greater than that of those in the embodiment first described.

Referring now to the embodiment of com- 45 posite beam affording double movement, illustrated in Fig. 4, the plates are again of quasi triangular form, there being eight plates in all, four of the plates, designated 20, being united by one pair of stool clips 21 and 22, and the other 50 four plates, designated 23, being united by another pair of stool clips 24 and 25, the plates 20 and 23 being interleaved or stacked alternately with their bases opposed and having their center portions united and appropriately secured by 55 means of ferrules 26.

It will be seen that while the overall dimensions of the beam illustrated in Fig. 4 are substantially the same as those of the previous embodiment illustrated in Figs. 2 and 3, owing to 60 its composite nature, double movement will be permitted when the forces are applied at the stool clips, as indicated by the arrows, and further additional strength is imparted to the beam. 65 Any appropriate form of washers or other spacing devices, indicated at 27, may be interposed between adjacent plates at the clips 21, 22, 24 and 25, and where desired such washers may 70 be of extended area and of friction producing material, such as Ferodo.

In Figs. 5 and 6 a modified form of composite beam is illustrated wherein the truncated apices of .the.respective plates 20 and 23 are in abut- 7) ment at 30, the desired disposition of the assembled plates being maintained under stress by girders 31 and 32 arranged above and below the beam and riveted through the plates 20 at 33 and through the plates 23 at 34.

Further to reinforce the centre portion of the beam and to prevent its buckling, the girders 31 and 32 are tied at each end by end plates 35 and 36 riveted to angle pieces 37, in turn riveted to the girders and it may be also to the spring plates 20.

As more clearly indicated in Fig. 6, each portion of the composite beam includes six spring plates, making twelve in all, it being appreciated that the invention may be adapted with any number of plates, the number, size and particular shape of the plates composing the beam being dependent on the purpose for which it is intended.

Reference being had now more particularly to Fig. 7 where the application of the invention to central buffing and draft gear for railway vehicles is diagrammatically represented, 40 designates a yoke to the front end 41 of which a coupler shank is adapted to be connected by a pin or cotter in the usual manner, 42 and 43 representing the center sills of the vehicle between which sills the buffing and draft gear is disposed.

The gear consists of two columns of springs 44 and 45 between followers 46, 47 and 48, 49 respectively, the front followers 46, 48 being mounted at the ends of a resilient beam such as the beam I described with reference to Figs. 2 and 3 of the drawings and constituting a support therefor, a wall 50 appropriately formed within the yoke providing a force exerting member for the resilient beam I.

Similarly the rear followers 47 and 49 are mounted at the ends of a rear beam composed of stacked plates such as the beam I, the force being applied to said beam via the yoke 40 which is equipped with an internal wall 51 abutting with the middle portion of the beam.

The front followers 46 and 48 are prevented from moving forwardly in regard to the vehicle on draft by means of abutments 52 and 53 on the center sills, corresponding abutments 54 and 55 engaging the rear followers 47 and 49 and pre50 venting their rearward movement on buff.

On draft, the yoke 40 is moved forwardly and constitutes a force exerting member operating through the wall 51 to move the rear transverse beam I and with it the rear followers 47 and 49 forwardly, thus compressing the two columns of springs 44 and 45 against the front followers 46, 48 and the front abutments 52, 53 by which the vehicle is propelled forwardly. The two columns of springs 44 and 45 thus function as draft cushioning devices and are assisted in this respect by the rear resilient beam 1.

When buffing, the yoke 40 is forced rearwardly and buffing shocks are cushioned by the two columns of springs 44 and 45 which are compressed against the rear followers 47, 49 by such rearward movement of the yoke which, acting through the wall 50 onto the center of the front beam I, produces rearward movement of the 70 front followers 46, 48. The two columns of springs thus act in parallel also to cushion buffing shocks and are assisted in this function by the front resilient beam I.

With any of the embodiments illustrated there 76 may be disposed between each pair of spring plates an intermediate friction plate, as previously mentioned in connection with the composite beam shown in Fig. 4.

Further, in all the embodiments, it will be noted that means are provided or the arrangements are such that the effecting forces or loads, in addition to being applied edgewise of the plates constituting the beam or spring, are applied simultaneously to and distributed uniformly between the several plates of such beam, in contradistinction to the usual leaf spring where the total force or load is necessarily accommodated by the master leaf and distributed by it to some extent only among the subsidiary leaves.

Also, in contradistinction to the usual leaf spring, in the beams or springs according to the invention, all the plates composing a beam are of the same or approximately the same shape and size and are coincidently assembled and secured, for instance by means of the rivets, ferrules and/or clips, so as to be prevented from relative movement one against the other. Substantially equal appropriation of load and stress by each one of the several plates is thereby further assured. Moreover, where desired, the edges of the plates may be swaged to give additional strength by minimizing the tendency of the metal to split under high tension, and it may be found necessary to use bolts or the equivalent midway between the abutments, e. g. between the stool I I and the stools 7 and 8 in Figs. 1 and 2 to counteract any tendency there may be for the beam to buckle under the strain of compression.

Instead of forming the beam from an assembly of spring tempered plates, it is within the invention to constitute such beam of one or more lengths of rolled steel of appropriate section tempered after rolling to increase the resistance to movement and power of recovery after stress under heavy pressures.

By the present invention flexible or resilient beams of considerable strength and utility are obtained which can be cheaply and easily fabricated. What I claim is:1. A stress-receiving member comprising a plurality of substantially flat stacked plates, said plates being stacked with their flat faces substantially parallel and in a direction substantially normal to that at which the force is to be applied, whereby the force is exerted in the direction of the edges of the stacked plates, said plates being of truncated or quasi-triangular shape, alternate plates being interleaved and the truncated apices and bases of one plate coinciding respectively with the base and truncated apices of next adjacent plates, and means securing the center portions of all of the stacked plates against relative movement. 2. A stress-receiving member comprising a plurality of substantially flat stacked plates, said plates being stacked with their flat faces substantially parallel and in a direction substantially normal to that at which the force is to be applied, whereby the force is exerted in the direction of the edges of the stacked plates, said plates being of truncated or quasi-triangular shape, said plates being stacked in two groups with the 70 truncated apices of the respective groups abutting and the bases of the respective groups being opposed, and means securing the center portions of the plates of both groups against relative movement. 15 3. A stress-receiving member comprising a plurality of groups of truncated or quasi-triangular shaped flat plates, means for securing the plates of each group against relative movement one against another, and for securing the groups of plates together to form a composite structure, the plates of each group being stacked with their flat faces substantially parallel and in a direction substantially normal to that at which the force is to be applied, the bases of the plates of each group being at opposite sides of the composite structure and adapted to have the force 6 exerted against them.

RICHARD THOMSON GLASCODINE.