IE57617B1 - Tool for inserting spiral members in holes - Google Patents

Description

The present invention relates to tools for inserting spiral members in holes whereby screw * threaded devices may be secured in receptive substrates, the spiral members improving the grip of 4 · such screw devices in receptive substrates e.g. wood or plastic or composite screw receivable materials and may be used to restore the grip of a screw in a hole made by the screw in such materials after a period of use.

The invention has been developed with the problems f(7 of screw-in rail spikes so called screw-spikes in mind but is not limited in its applicability, it is believed, only to this application though it will be specifically described with reference to such an application.

Attention is directed to our copending Irish Application No. $5^ bib which describes and claims such spiral members and discusses their application and use.

The bottom end of the spiral member in the above 2.0 mentioned application is shaped so as to be disconnectably engageable by a tool inserted down the centre of the spiral member whereby the force to screw the spiral member into the hole can be exerted from the bottom end of the spiral member. * This enables the spiral member readily to be inserted in the hole because screwing the spiral member in from the bottom tends to cause it to reduce its diameter.

According to the present invention there is provided a tool for inserting a spiral member which comprises a shaft adapted to extend through the spiral with engaging means at its bottom end adapted to engage the bottom end of the spiral and driving means at its g other end and stop means near the drive means adapted to prevent the shaft penetrating beyond the bottom of the hole, the driving means being such as to enable'the tool to releasably engage the spiral member so as to provide a driving engagement whilst the assembly is being screwed into the sleeper but a non-driving engagement when the tool is screwed out of the hole, by rotation in the opposite direction. Preferably the tool is provided with means for holding the turns of the spiral member in axially spaced apart relationship.

IS£ In a preferred form of the invention a tool for inserting into a hole in a body of screw-receiving material a spiral member which is cylindrical or is tapered towards one end and is turned inwardly back down its axis at one end, or at the narrower end when 2.0 it is tapered, to afford a drive pin, comprises a shaft arranged to extend through the spiral member, the tool having drive means at one end and stop means near the drive means adapted to prevent the shaft penetrating beyond the bottom of the hole in the screw-receiving material, the shaft having a spiral thread arranged to receive the spiral member, the tool having, at its end remote from the drive means, engagement means arranged to engage drivingly the drive pin of the spiral member.

The outer surface of the thread is preferably lo flattened. The engagement means may comprise an axial hole and a radially extending shoulder extending out from the axial hole. The drive means may comprise a rectangular head, and the stop means may comprise circular shoulders. The tool may be a cut-down rail spike or may be in the form of a cut-down rail spike.

The invention also extends to an assembly of a tool in accordance with the present invention and a spiral member as claimed in any claim of ·. . Application No. 51 blfe in which the tail of the drive pin of the spiral member is located in an axial hole in the end of the tool, the relationship of the tail of the drive pin to the hole being such that whilst the assembly is screwed into a hole in a substrate from which a screw has been removed it remains in the hole in the tool but the tool can rotate away from the tail of the drive pin and leave the spiral member in place.

The preferred embodiments of the tool described below enable a spiral member of malleable material to be inserted rapidly and the insertion tool to be removed very quickly and moreover using conventional tools such as power wrenches.

In addition the tool does not project up above the level of the rails, except possibly right at the end of the withdrawal cycle.

Thus in the event that the insertion tool has to be left in place while a train is passing there will be little or no danger of the wheels of the train striking the tool.

The modified arrangement involves a modification td the spiral member and the provision of a cooperating insertion tool. These interact so that the spiral member can be threaded onto the tool prior to insertion in the hole, the assembly then screwed into the hole and then the tool scre**sd out of the hole leaving the spiral member in place.

This is achieved by making the tool in a form amounting to a cutdown version of the rail spike which is to be secured in the worn sleeper by means of the spiral member. Thus the rectangular head and circular shoulders are unchanged, the shank may be turned down ς- to reduce its diameter slightly to ensure free passage through the chair, and the shank at its junction with the first turn of the thread is turned-down sufficiently to prevent it gripping the inside of the hole.

The threads are turned-down to tapered flats, the iO taper being greater than that of the screw spike with ' which the spiral member is to be used. A rectangular groove is formed between each flat. The axial length of the grooves e.g. 1/4" (6.3mm) may be such as to provide a clearance on either side of each turn of the spiral member e.g. the axial length of each groove being desirably 101% or 105% or 110% to 120% or 130% e.g. about 115% of the maximum axial length (e.g. 5.5 mm) of each turn of the spiral member. The depth of each rectangular groove is about 5/64 (2 mm).

It will be appreciated that the reference to turning down of the screw-spike does not dictate the way in which the tool may be made merely its form.

Whilst an exact fit could be used it may facilitate mounting of the spiral member on the tool for there to be some play between the spiral member and the tool in the axial direction.

It may also be desirable for the length of the spiral member to be slightly greater than the length of the corresponding grooves in the tool so that whilst there is some play allowing rapid winding of the spiral member onto the tool nonetheless the spiral member is gripped between the upper shoulder of the uppermost groove and the lower shoulder of the lowermost groove in which the upper and lowermost turns of the spiral member are nested.

Means are provided to enable the tool to releas5 ably engage the spiral member so as to provide a driving engagement whilst the assembly is being screwed into the sleeper but a non-driving engagement when the tool is screwed out of the hole, by rotation in the opposite direction. »o This may be achieved by turning the lower end of the spiral member inwardly as in the embodiment described above but then axially upwardly and providing a corresponding axial hole in the lower end of the tool in which the upturned end of the spiral member can nest and an e.g. axially extending shoulder projecting out from the hole e.g. radially which engages with the inturned end of the spiral member, the free end of which is in effect locked in the axial hole of the tool. The senses of the shoulder and the inturned o portions are arranged to be such that the shoulder engages the inturned end of the spiral member during the screwing-in movement and rotates away from it during the screwing out movement.

The invention may be put into practice in various 2-sr ways and a number of specific embodiments and certain accessories for use therewith will be described by way of example to illustrate the invention with reference to the accompanying drawings, in which: Figure 1A shows in elevation an inserting tool in accordance with the invention for inserting a spiral member in accordance with Application No. 5~7G<1» Serial No. 2163510; Figure 1B is an elevation of the lower end of the kJ lO IJ 2.0 so tool shown in Figure IA viewed from the opposite side and showing the interior structure in cross-section; Figure 1C is an end view looking up the tool from the lower end; Figure 2 is a view similar to Figure 1A and shows the tool of Figure 1 with a spiral member in accordance with the above mentioned specification wound onto the tool and the spiral member fully inserted in the sleeper just prior to commencement of the unwinding of the insertion tool which will leave the spiral member in the hole ready for insertion of a spike; and Figure 3 is an end view of the assembly of Figure 2 seen from below showing how the tool engages the spiral member during insertion yet is free to rotate away during tool withdrawal.

The preferred form of the insertion tool in accordance with the present invention which is shown in the drawings is in a form amounting to a cutdown version of the screw-spike which is to be secured in the worn sleeper by means of the spiral member.

A typical British screw spike is as follows. The root of the spike is tapered from top to bottom, the line joining the lowest points of each root between adjacent turns, the root line, being inclined at an angle to the centre line. The taper is typically 1 mm in the 4 inches (10.2 cm) length of the screw-threaded portion of the spike, but some screw-spikes are not tapered. The root carries a single helical thread which engages the sleeper. The thread has an upper face disposed at an angle A of about 70° to the longitudinal axis of the screw-spike and a lower face disposed at an angle B of about 30° to the same axis.

The thread extends out a distance (the radial depth) from the root line of about 3.1 mms or more broadly 2.5-3.5 mms.

The precise dimensions of screw spikes used in some other countries (and which might be made in the U.K. and exported) differ from those used in the United * Kingdom but are of similar orders of magnitude. The spiral member and thus the insertion tool is modified for such other countries to have the same or similar relationship to the spike.

Thus the tool has a rectangular head 160 and •ο circular shoulders 161 unchanged from the screw spike, the shank 162 may be turned-down to reduce its diameter slightly to ensure free passage through the chair, and the shank 162 at its junction with the first turn of the thread is turned-down sufficiently to prevent it ,r* gripping the inside of the hole.

The threads are turned-down to tapered flats 164, the taper being greater than that of the screw-spike with which the insert is to be used namely 13-17 or 1418 mm internal diameter as compared with 16-17 mm, the 2.0 lower value being at the bottom of the spiral. A rectangular groove 165 is formed between each flat. The axial length of the grooves e.g. 1/4 (6.3 mm or 7 mm) is preferably such as to provide a clearance on either side of each turn of the spiral member so that the spiral member is relatively loose on the tool e.g. the axial length of each groove being desirably 101 or 105% or 110 to 120% or 130% e.g. about 115% of the maximum axial length (e.g. 5 mm) of each turn of the spiral member. 3z> The depth of each rectangular groove is about /64 (2 mm).

The lower end of the spiral member 140 is turned £Τ ϋ ιΟ 2.7) into the longitudinal axis of the spiral member and is bent up and back to lie along the said axis and to extend about 1 turn length back straight up the axis of the spiral member to form a drive pin. This tail 182 of the drive pin is about 6 nuns across and the bottom end of the insertion tool has a longitudinal axial hole 166 in which the axial tail of the drive pin of the spiral member is a close but free fit e.g. it may be a hole of about 7 mms diameter (see Figure 3). The hole 166 is longer axially than the tail 182 of the drive pin. The bottom end of the insertion tool also has a generally radially extending shoulder 167 extending out from the hole 166 (see Figures *£ ’’-and). This shoulder engages the in-turned end portion 201 of the drive pin of the spiral member and as shown in Figure 3 is preferably rounded to ensure that the malleable drive pin of the spiral member is not sheared by the hard metal of the insertion tool.

The shortest length which the tail and axial hole can be and achieve their desired function is not known but they must be of such length and diameter relative to each other as to generate sufficient clamping action to prevent the shoulder 167 drawing the tail 182 out of the axial hole 166 before the spiral member is fully inserted in the hole with its upper end beneath the surface of the sleeper (so that it is located in place in the sleeper; if this locking is not achieved the top turn would lift and the screw-spike would be more difficult to start in the spiral member).

The effect of friction of the upper turns and the end digging into the wood prevent the spiral member unwinding when the insertion tool is unwound.

It will be appreciated that if such clamping or .30 frictional engagement does not occur the tail would be drawn out of the hole and thus due to the malleability of. the preferred materials the spiral member would be deformed to conform to the groove in the insertion tool and would cease to be screwed in and the insertion tool would merely rotate through the stationary spiral member into the hole.

Claims (11)

1. A tool for Inserting a spiral member which comprises a shaft adapted to extend through the spiral member with engaging means at its bottom end adapted to £ engage the bottom end of the spiral and driving means at its other end and stop means near the drive means adapted to prevent the shaft penetrating beyond the bottom of the hole, the driving means being such as to enable the tool to releasably engage the spiral member to so as to provide a driving engagement whilst the assembly is being screwed into the sleeper but a nondriving engagement when the tool is screwed out of the hole, by rotation in the opposite direction.

2. A tool as claimed in Claim 1 provided with ,£* means for holding the turns of the spiral member in axially spaced apart relationship.

3. A tool for inserting into a hole in a body of screw-receiving material a spiral member which is cylindrical or is tapered towards one end and is turned 2.0 inwardly back down its axis at one end or at the narrower end when it is tapered to afford a drive pin, the tool comprising a shaft arranged to extend through the spiral member, the tool having drive means at one end and stop means near the drive means adapted to prevent the shaft penetrating beyond the bottom of the hole in the screw-receiving material, the shaft having a spiral thread arranged to receive the spiral member, the tool having, at its end remote from the drive means, engagement means arranged to engage drivingly the drive pin of the spiral member.

4. A tool as claimed in Claim 3 in which the outer surface of the thread is flattened.

5. A tool as claimed in any one of Claims 1 to 4 in which the engagement means comprise an axial hole and a radially extending shoulder extending out from the axial hole.

6. A tool as claimed in any preceding claim in which the drive means comprise a rectangular head, and to the stop means comprise circular shoulders.

7. A tool as claimed in any preceding claim which is a cut-down rail spike or is in the form of a cut-down rail spike.

8. A tool for inserting a spiral member into a hole, constructed and arranged substantially as herein specifically described with reference to and as shown in Figures 1A, 1B and 1C and 2 and 3 of the accompanying drawings.

9. An assembly of a tool as claimed in any one 2.0 of Claims 1 to 8 and a spiral member as claimed in any claim of Application No. 5~7b)b in which the tail of the drive pin of the spiral member is located in an axial hole in the end of the tool, the relationship of the tail of the drive pin to the hole being such that * whilst the assembly is screwed into a hole in a substrate from which a screw has been removed it remains in the hole in the tool but the tool can rotate away from the tail of the drive pin and leave the spiral member in place.

10. An assembly as claimed in Claim 9 substantially as specifically described herein with reference to Figures 2 and 3 of the accompanying drawings.

11. A tool for inserting a spiral member substantially as described herein with reference to the accompanying drawings.