Loading means for underpinning machines

Abstract: A magazine (10) for V-nails for use in underpinning of picture frames receives a strip of V-nails secured together by heat-bonded non-adhesive synthetic plastics material through an opening (14) of greater width than the V-nails. A pusher means (25) has a downwardly projecting tongue (20) which is driven by conventional means in the machine and has depending side walls (30) at its forward end affording a contact point (33) for pushing the V-nails at their centre of gravity towards a pair of locating formations (17) and the extreme forward end. A single V-nail (34,35) which may be presented either point foremost or point rearmost, is removed from the end of the strip in the underpinning operation, the magazine being cut away (at 16 and 17) and the pusher means being cut away (at 40) to permit this operation. On return of the drive means, a cam (23) firstly returns the pusher means (25) to stop means (27) in the magazine (10) and then lifts the magazine from its operative position to enable it to be removed or refilled. Advantages of the arrangement are that the magazine is robust and re-usable and can quickly be refilled and also that it can receive V-nails in strip form irrespective of their orientation being either point foremost or point rearmost.

Description: This invention relates to a loading means for underpinning machines for example for the manufacture of picture frames. Underpinning is carried out using V-shaped fixings known as V-nails or wedges, each being of thin sheet metal and having one sharp edge adapted to be driven into a frame joint by a hammer of an underpinning machine. The V-nails are small and thin and are difficult to handle so it has been proposed to package a large number side by side in a disposable cartridge which is inserted in the underpinning machine. When the cartridge is empty, it is removed and discarded. This procedure is wasteful but hitherto no satisfactory alternative has been proposed which enables quick and easy loading of V-nails in the correct orientation into an underpinning machine. It is an object of the present invention to provide a new or improved loading means. It is known from US-A-4378065 to provide a loading means for fasteners comprising a magazine in which the fasteners are held in a side-by-side array. US-A-4378065 relates to a magazine for holding wire staples which are driven by manual use of a hammer but comprises a magazine having an opening at its forward end in its upper and lower faces through which a single fastener can be removed in the axial direction of the fastener to perform a fastening operation. The magazine further includes a captive pusher means slidable along the magazine from the rearward to the forward end to push the fasteners towards the forward end for use. However, the magazine is not adapted for use in an underpinning machine and has no means for automatic driving of the fasteners towards the forward end. The disposable cartridge for an underpinning machine is adapted to be connected to a power drive to supply the V-nails to the underpinning head of the machine but must then be removed and discarded. According to the invention there is provided a loading means for fasteners comprising a magazine adapted to hold a plurality of fasteners in a side-by-side array, at least part of the magazine having an upper opening, the forward end of the magazine having an opening in its upper and lower faces through which a single fastener can be removed in the axial direction of the fastener in a fastening operation, the rearward end of the magazine including stop means, the magazine further including a captive pusher means slidable along the magazine from a rearward end thereof and adapted to push fasteners towards said forward end, the pusher means including a downwardly projecting tongue, the magazine being re-usable; characterised in that the magazine is constructed and arranged to hold a plurality of V-nails for use in an underpinning machine; said upper opening is of greater width than the V-nails, whereby they can be inserted into the magazine; the downwardly projecting tongue of the pusher means is provided towards its forward end and is adapted to engage an external drive means of the underpinning machine to push the V-nails forwardly towards the underpinning head of the underpinning machine, the pusher means also having a downwardly extending cam towards its rearward end, return movement of the drive means away from the underpinning head engaging the cam to firstly return the pusher means to the stop means and then to lift the magazine. Preferably the V-nails are provided in a convenient form for the loading means described. A strip of V-nails may be provided for use in the loading means as set out above, the V-nails being releasably secured together in a side-by-side array by means of a localised strip of heat bonded, non-adhesive synthetic plastics material. A magazine embodying the invention will now be described in more detail by way of example only with reference to the accompanying drawings in which, Figure 1 is a plan view of a preferred embodiment of the magazine of the loading means, Figure 2 is a side elevational view of the magazine of Figure 1, Figure 3 is an end elevational view of the magazine of Figure 1, Figure 4 is a plan view of a pusher, drawn to an enlarged scale, Figure 5 is a longitudinal section of the pusher of Figure 4, Figure 6 is an end elevational view of the pusher of Figures 4 and 5. The magazine shown in the drawings is intended for use with a strip of V-nails releasably secured in side-by-side array. While this may be done by various methods, it has been found that the use of a localised strip of heat bonded, non-adhesive synthetic plastics material is greatly to be preferred since it enables the V-nails to be driven individually without difficulty and also prevents build-up of adhesive on the underpinning machine hammer, the magazine or the frame being made. The magazine 10 comprises a rectangular cross-section assembly having a top member 11 and a bottom member 12. These are fitted together and spot welded to form a tubular assembly having, in its upper surface, an elongate opening 13. The rearward portion of the opening 13 is enlarged at 14 to a width slightly greater than the width of a V-nail (not shown) so as to enable a strip of V-nails to be inserted through this portion of the magazine and slid to the forward end. The forward end has a through opening including an arcuate cut-out 15 in the lower member 12 and a larger rectangular opening 16 in the upper member 11 so that a hammer of an underpinning machine can strike a single V-nail at the extreme free end of the magazine and drive it into position in an underpinning operation. A very small in-turned retaining lip 17 is provided at each side of the operative forward end of the magazine so as to prevent the V-nail strip from falling through the opening 15,16 in use. V-nails vary in size, that is in vertical height, and it is therefore necessary to provide a magazine for a specific height of V-nail. In the form shown in Figures 1-3, relatively shallow V-nails are to be housed and a pair of small downwardly depending lugs 18 is provided at the front and rear ends of the magazine 10 to enable it to be lodged in a standard underpinning machine. Where the depth of the V-nail is greater, the depth of the lower part 12 of the magazine is increased and there is no need to provide the lugs 18 for the largest size. The V-nails are pushed towards the operative forward end, that is the right-hand end in the drawings, by means of a pusher 25 shown in Figures 4-6 of the drawings. The pusher 25 comprises a generally U-shaped metal member which is held captive in and is slidable in the tubular magazine. The forward ends 19 of the walls 30 of the pusher 25 abut the strip of V-nails in use. A portion of the blank is turned down to form a depending tongue 20 in the finished pusher 25, supported by a reinforced corner 21. The pusher can be made of different depths by cropping the blank to produce side walls 30 of an appropriate depth. A small chamfer 31 is provided at an angle of approximately 15° in the lower part of the side walls 30 and a similar chamfer 32 is provided at the upper part of the side walls. The chamfer 31 is of constant height irrespective of the depth of the side walls so that the point 33 bears on the centre of gravity of the upstanding V-nails in the strip to ensure smooth pushing. Towards the rearward end of the pusher 25, a cam 23 is provided. In a conventional underpinning machine, a drive member is pushed forwardly towards the underpinning head so as to move a plurality of V-nails forwardly to be used. The drive member has an upstanding pin. This conventional drive member is utilised with the magazine described above. It bears on the rearward face of the tongue 20 and pushes the pusher 25 forwardly in the tubular magazine, thereby pushing the V-nails towards the operative end and the discharge opening 15,16. Thus, in normal operation, the V-nails are fed from the magazine in a way similar to that used for the feeding of V-nails in the conventional disposable cartridge. However, it is necessary firstly to be able to remove the magazine and secondly to be able to re-load it. Loading has previously been described by inserting the strip of V-nails through the enlarged opening 14 in the top member 11. In order to do this, the magazine need not be removed from the machine. When all the V-nails have been inserted, the drive member is manually withdrawn. Initially, the upstanding pin engages against a first cam face 24 of the cam 23 and draws the pusher 25 rearwardly. When it reaches the rearward end of the magazine, an upstanding stud 26 on the upper surface engages a cut-out 27 on a bridging member of the top member 11 of the magazine and prevents further travel, holding the pusher 25 captive. As the drive member is further withdrawn, it rides along the cam surface 24 and lifts the magazine to an upwardly tilted condition. In this condition, it can be manually grasped and pulled from the machine. Once the magazine has been re-loaded, or an alternative magazine has been prepared if there is to be change of type of V-nails to be used, the magazine is inserted into the machine and allowed to drop fully into the horizontal operative condition. When the drive member is operated, the pin comes into abutment with the tongue 20. As the movement of the drive member is obstructed by the magazine lying horizontally, the pin firstly contacts the other cam face 28 and lifts the magazine to a tilted condition until the pin can pass the cam 23. The magazine then drops to the horizontal condition and the pin moves forwardly to abut the tongue 20. Thereafter, the pin pushes the pusher 25 forwardly and hence brings the V-nails into operative condition. It will be seen from Figure 1 that the V-nails can be fed either point foremost or wings foremost as indicated in dotted lines at 34 and 35. This enables the magazine to be used with an underpinning machine having multiple underpinning heads. A dimple 36 is formed in the top surface of the pusher simply to render it captive within the body of the magazine. It will be appreciated that the use of a loading means embodying the invention greatly reduces the wastage currently taking place because of the use of single use cartridges. The magazine can be substituted directly for a conventional cartridge without modification of the machine or the drive arrangements. By the use of a strip of V-nails releasably secured together by heat bonded, non-adhesive synthetic plastics material, loading of the magazine is straight forward.

Claims: A loading means for fasteners comprising a magazine (10) adapted to hold a plurality of fasteners in a side-by-side array, at least part of the magazine having an upper opening (14), the forward end of the magazine (10) having an opening (15,16) in its upper and lower faces through which a single fastener (34,35) can be removed in the axial direction of the fastener in a fastening operation, the rearward end of the magazine (10) including stop means (27), the magazine further including a captive pusher means (25) slidable along the magazine (10) from a rearward end thereof and adapted to push fasteners towards said forward end, the pusher means (25) including a downwardly projecting tongue (20), the magazine being re-usable; characterised in that the magazine (10) is constructed and arranged to hold a plurality of V-nails for use in an underpinning machine; said upper opening (14) is of greater width than the V-nails, whereby they can be inserted into the magazine; the downwardly projecting tongue (20) of the pusher means (25) is provided towards its forward end and is adapted to engage an external drive means of the underpinning machine to push the V-nails forwardly towards the underpinning head of the underpinning machine, the pusher means also having a downwardly extending cam (23) towards its rearward end, return movement of the drive means away from the underpinning head engaging the cam (23) to firstly return the pusher means (25) to the stop means (27) and then to lift the magazine. A loading means according to Claim 1 further characterised in that the pusher means (25) is of inverted generally channel section. A loading means according to Claim 2 further characterised in that the pusher means (25) has downwardly depending side walls (30) at the forward end, each side wall having a pushing edge (31,32) adapted to engage the V-nails. A loading means according to Claim 3 further characterised in that the pushing edge of each side wall is chamfered (31,32) to provide a pushing contact point (33) corresponding to the centre of gravity of the V-nails, the V-nails being slid either point foremost or wings foremost. A loading means according to Claim 3 or Claim 4 further characterised in that the pusher (25) has a cut-out (40) between the side walls (30) to permit passage of an underpinning machine hammer. A loading means according to any one of Claims 1-5 further characterised in that the magazine (10) has a pair of locating formations (17) at the extreme forward end adapted to hold said single V-nail (34,35) to be removed in an underpinning operation. A loading means according to any preceding claim and containing a strip of V-nails releasably secured together in side-by-side array by means of a localised strip of heat-bonded, non-adhesive synthetic plastics material. An underpinning machine having a loading means according to any one of Claims 1-7.

Inventors: JOYCE WALTER ALFRED JAMES, JOYCE, WALTER ALFRED JAMES
Applicants: JOYCE W & M ENG LTD, MAGNOLIA GROUP PLC, W. & M. JOYCE ENGINEERS LTD.
Application year: 1992
Main classification: B25C5
IPC codes: B25C5