GB2261185A

GB2261185A - Coil spring compressor

Info

Publication number: GB2261185A
Application number: GB9118174A
Authority: GB
Inventors: Andrew William Bradley; Melvyn Thomas Fryer
Original assignee: Sykes Pickavant Ltd
Current assignee: Sykes Pickavant Ltd
Priority date: 1991-08-23
Filing date: 1991-08-23
Publication date: 1993-05-12
Also published as: GB9118174D0

Abstract

A coil spring compressor for use with helical compression springs comprises a fixed lower and a movable upper horseshoe shaped shoe member (10) mounted on respective carriage blocks, the upper carriage block (109) being carried on a threaded rod (102) for movement towards and away from the lower fixed carriage block (112). Both shoe members are mounted on supports (110, 113) extending outwardly of their respective carriage blocks for restricted pivotal movement about an axis normal to the direction of movement of the movable shoe. Each shoe includes an arm (8), Figs 2 and 3 (not shown), extending parallel to its carriage block between two stops located on either side of the said respective spigot whereby the degree of pivotal movement is restricted to a maximum of 15 DEG . The shoe members may be in the form of horseshoe shaped bars comprising two arm portions (2, 3) from the free ends of which extend radially inwardly directed hook members (11, 12) to engage one coil of the spring. Two further hook members (20, 21), located on either side of the pivotal mounting, extend radially inwardly from the rear of each shoe member to engage the same coil. <IMAGE>

Description

COIL SPRING COMPRESSOR The present invention relates to a coil spring compressor for use with helical compression springs such as those used in independent suspensions for motor vehicles.

Spring compressors used in the dismantling of coil springs in motor cars, such as HcPherson-type independent suspension assemblies, are well known. Generally such compressors comprise upper and lower semi-circular U-shaped shoes which define grooves to receive the coils of a spring to be compressed. To assist in locating the spring coils in the shoes the latter are frequently obliquely coiled. The U-shaped shoes are generally nonrotatably mounted on carriages located on a longitudinally extending body, one of such carriages being linearly adjustable, e.g. by engagement with a threaded spindle rotation of which move the said one shoe towards or away from the other.

We have now developed an improved form of coil spring compressor in which both shoes are mounted for limited free pivotal movement about an axis normal to the direction of movement of the at least one moveable shoe.

The degree of pivotal movement is preferably limited to a maximum of about 300 most preferably about 15=.

The limited free rotation allows the shoes to locate more securely on the coil and to take up the position of the coil as the spring is compressed or released from compression. As a result the spring is less likely to slip out of the shoes when in the fully compressed condition even when, for example, the compressed coil spring assembly is dropped, as may happen in a garage workshop.

The shoes used in the compressor of the present invention are preferably in the form of a horse-shoe shaped bar from the ends of each arm of which two hook members are directed inwardly, preferably radially, to engage a coil of the spring. At least one inwardly directed hook member extends from the back of the shoe to engage the same coil of the spring. In a preferred embodiment two such hooks, in parallel relationship, are located one on either side of the point of pivotal location of the shoe on the carriage block. The hooks preferably comprise generally cup-shaped members the outer edge of which are shaped, on the inside surface, to conform generally with the curvature of a coil spring.

Each shoe is mounted on a carriage block including a hollow spigot onto which the shoe is rotatably secured, the carriage further including, spaced from the spigot, two stops positioned at either side thereof.

An arm element extends from the shoe parallel to the carriage such that, when mounted on the block, the arm is in sliding contact with the carriage and extends to a point between the said stops, to limit the degree of pivotal movement of the shoe about the spigot.

The dimensions of the arm and the distance apart of the slots being arranged to provide the required degree of free pivotal movement.

One embodiment of the invention will now be described by reference to the accompanying drawings in which: Figure 1 is a plan view of one shoe used in the present invention; Figure 2 is a view along A, B of the rear of the shoe of Figure 1, Figure 3 is a view along B, A from the front of the shoe of Figure 1, Figure 4 is a section through the compressor body, Figure 5 is a front view of the upper shoe carriage member of Figure 4.

Referring to Figures 1 - 3 and 5 of the drawings. A part spherical horse shoe shaped shoe, generally indicated at 10, comprises a mounting portion 1 from which extend two oval section arms 2 and 3. Mounting portion 1 has a flat rear face into which extends1 at right angles, to the face 1 a hollow circular recess 5 to receive the hollow spigot 110 of body carriage member 109 (Figures 4 and 5). A circular passageway 6 extends from recess 5 to communicate with a second hollow recess 7 formed in the front face of the carriage to receive the shank and head respectively of an allen screw (not shown).

An arm element 8 extends from the rear of shoe 10 at right angles to the axis of recess 5 and 7 such that its end portion will be located between stops 114, 115 on carriage 109 when mounted on spigot 110. The distance apart of the stops 114, 115 and the shape and angle of the arm are arranged such that the shoe is enabled to pivot through 5o in a clockwise direction and up to 25 in an anticlockwise direction either side of the vertical axis X-Y when viewed from the rear of the shoe as illustrated in Figure 2. The axis of arm 8, C-D in Figure 2, is at 10 to the vertical axis X-Y and the arms 8a, 8b at 200 to the vertical (Figure 2).

End elements 11 and 12 of arms 2 and 3 extend radially inwardly of the shoe and comprise cup shaped elements 13 and 14 dimensioned to receive a coil of a spring, edge portions 15 and 16 being shaped to generally conform with the curvature of the coil.

As shown in Figures 2 and 3 arms 2 and 3 are obliquely curved to conform generally with the helical shape of the coil spring when in a generally un-compressed state.

Additional coil receiving elements 20 and 21 extend inwardly of the arms 2 and 3 from positions either side of recesses 5 and 7 and in directions substantially parallel to the axis A - B of recesses 5 and 7 and include lip portions 22 and 23 shaped to conform with the curvature of a coil spring. As clearly shown in Figures 2 and 3 the levels of supports 20 and 21 lie on the oblique curve of arms 2 and 3 to conform generally with the helical shape of the coil spring.

It is to be understood that both the upper and lower shoes have the same shape and dimensions and are secured to the body as hereinafter described in an opposed relationship whereby a coil spring may be engaged therebetween.

The compressor body is shown in Figure 4. The body, generally indicated at 100, comprises an elongate rectangular hollow frame 101 in the interior of which is located a threaded rod 102 carried in bearin8s 103, 104 at either end of the body. Rotation of the threaded rod 102 is achieved via the hexagon head 105 retained on a portion 102a of rod 102 through bearing 103 by a shear pin 106. A carrier block 107 screw threadedly engages the rod 102 within body 101. A slot 108 is provided longitudinally of one side of the body 101. T-shaped fingers 109a, 1O9b of carriage 109 extend through slot 108 define a recess 109c that slidingly engages with block 107.The T-head portion of the fingers engage within the body either side of the slot 108 to prevent the carriage disengaging from the slot. A second fixed carriage 112 is fixedly located at the bottom of the body and encompasses the bearing 104.

Carriages 109 and 112 are mirror images of the other and have outwardly extending hollow spigots 110 and 113 respectively to engage in recess 5 of shoes 10. Hollow spigots 110 and 113 are internally screw threaded to receive an allen screw (not shown) for locating shoes 10 thereon.

In Figure 5 is shown a face view of an upper adjustable carriage 109, it is to be appreciated that the view of the lower fixed carriage 112 will be the same view turned through 1800 about the spigot 110. At the upper end of carriage 109 are located stops 114 and 115 which control the degree of pivot movement of shoes 110 as described above.

Attached to the opposite side of body 101 to slot 108 is a handle 120 to facilitate carrying the body unit.

In use shoes 10 of an appropriate size to suit the spring to be compressed are secured on carriages 109, 112 in an opposed relationship. Rod 102 is rotated on a hexagon head 105 to separate carriages 110 and 112 to an extent sufficient to allow upper and lower shoes 10 to engage on coils of the spring adjacent the opposite ends thereof. Since the shoe arms 2 and 3 are obliquely curved and limited pivotal movement of the shoe is permitted about spigots 110 and 113, the spring coils are engaged by both end cups 13 and 14 and receiving elements 20 and 21.

To compress the spring, hexagon head 105 is rotated in the opposite direction using a suitable spanner to cause block 107 and carriage 110 carrying the upper shoe to move into a closer relationship. As the spring is compressed the helices of the coil adopt a flatter pitch, but because the shoes are able to rotate about the carriage spigots the cups 13, 14 and elements 20 and 21 are enabled to remain in engagement with the spring coil. Because all of the spring gripping elements of the shoes remain in contact with the coils during compression the risk of accidental slippage of the spring out of the shoes is greatly diminished.

Claims

1. A coil spring compressor comprising upper and lower shoe members adapted to engage the coils of a spring to be compressed, at least one of said shoes being moveable towards and away from the other said shoe whereby compression and relaxation of the coil spring may be achieved, wherein both shoes are mounted on carriage blocks for pivotal movement about an axis normal to the direction of movement of the at least one moveable shoe.

2. A coil spring compressor according to claim 1 wherein the degree of pivotal movement is limited to a maximum of 300.

3. A coil spring compressor according to claim 2 wherein the degree of pivotal movement is limited to a maximum of 15".

4. A coil spring compressor according to any one of the preceding claims wherein each said carriage block is provided with a spigot extending outwardly normal to the direction of movement of the said at least one shoe and each said shoe includes a circular passageway extending therethrough for sliding engagement on said hollow spigot and including means for retaining said shoes on said blocks.

5. A coil spring compressor according to claim 5 wherein each said carriage block includes, spaced from said spigot, two stop members positioned to each side thereof and each said shoe includes an arm element extending parallel to the carriage block such that, when mounted on the block, the arm is in sliding contact therewith and extends to a point between the said stops whereby the degree of pivotal movement of the shoe about the spigot is restrained.

6. A coil spring compressor according to any one of the preceding claims wherein each said shoe is in the form of a horseshoe shaped bar comprising two arm portions from the free ends of which extend hook members directed inwardly to engage a coil of the spring.

7. A coil spring compressor according to claim 6 wherein the hook members are directed radially inwardly.

8. A coil spring compressor according to claim 6 or 7 wherein at least one inwardly directed hook member extends from the rear of the shoe to engage the same coil of the spring as the hook members extending from the free ends of the shoe.

9. A coil spring compressor according to claim 8 wherein two hook members, in parallel relationship, are located one on either side of the point of pivotal location of the shoe on the carriage block.

10. A coil spring compressor according to any one of claims 6-9 wherein the hook members are generally cup shaped the outer edges of which are shaped, on the inside surface, to conform generally with the curvature of a coil spring.

11. A coil spring compressor according to any one of the preceding claims wherein the moveable carriage block is carried on a threaded rod located within an elongate hollow body and mounted in bearings located at either end of the said body the other said block being fixed at one end of the said body, rotation of the threaded rod causing the moveable carriage block and associated shoe to move towards or away from the fixed carriage block and shoe.

12. A coil spring compressor substantially as herein described with reference to the drawings.