US3888721A

US3888721A - Apparatus for attaching fiberglass handles

Info

Publication number: US3888721A
Application number: US473725A
Authority: US
Inventors: Joseph Allen Carmien; Elbert Davis; Roger G Cervi
Original assignee: Nupla Corp
Priority date: 1974-05-28
Filing date: 1974-05-28
Publication date: 1975-06-10
Anticipated expiration: 1992-06-10

Abstract

An apparatus for attaching fiberglass handles to tools and for making other fiberglass connections. Four gear wheels are intermeshed for simultaneous rotation 90* out of phase with each other. Cup members connected to the gear wheels engage the upper ends of four tool handles. As the gear wheels rotate, the cup members force the handles downwardly into the eye openings of tool heads. Downward movement of the handles becomes progressively slower along the final portion of the insertion so that potting compound is not spilled out of the eye opening and the potting compound flows evenly between the handle and the eye opening for complete bonding.

Description

United States Patent 1 Carmien et al.

[ June 10, 1975 1 APPARATUS FOR ATTACHING FIBERGLASS HANDLES [73] Assignee: Nupla Corporation, Sun Valley,

Calif.

[22] Filed: May 28, 1974 [21] Appl. No.2 473,725

[52] US. Cl. 156/423; 29/244; 29/458; 29/525; 76/103; 156/293 [51] Int. Cl. 329d 3/00; C72b 3/00 [58] Field of Search 156/556, 293, 423; 29/525, 29/458, 238, 244, 251, 253; 76/103 [56] References Cited UNITED STATES PATENTS 755,005 3/1904 Shoemaker 29/24-1 1,420,424 6/1922 Hallett 29/238 12/1953 Graf et a1 156/293 4/1970 Norcross 156/293 Primary Examiner-Douglas J. Drummond Attorney, Agent, or Firm--Robert C. Comstock [5 7 ABSTRACT An apparatus for attaching fiberglass handles to tools and for making other fiberglass connections. Four gear wheels are intermeshed for simultaneous rotation 90 out of phase with each other. Cup members connected to the gear wheels engage the upper ends of four tool handles. As the gear wheels rotate, the cup members force the handles downwardly into the eye openings of tool heads. Downward movement of the handles becomes progressively slower along the final portion of the insertion so that potting compound is not spilled out of the eye opening and the potting compound flows evenly between the handle and the eye opening for complete bonding.

10 Claims, 6 Drawing Figures APPARATUS FOR ATTACHING FIBERGLASS HANDLES BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to an apparatus for attaching fiberglass handles to tools such as hammers, sledges, axes, lopping shears, etc., and for making other fiberglass connections.

2. Description of the Prior Art In making fiberglass connections, the glue line thickness has a very direct bearing on the quality of the assembly. A thick glue line is far less desirable and less strong than a thin one. In order to achieve a thin line, the outer dimensions of the handle must be extremely close to the inner dimensions of the tool head opening. This creates an extremely narrow passage through which the potting compound must travel.

For efficient assembly, one end of the tool head opening is closed, hence it becomes a blind opening and fluids (including both liquids and air) can move only through the single opening. A charge of potting compound is placed in the bottom of the tool head opening prior to insertion of the handle. As the handle is inserted into the opening, it causes the potting compound to flow upwardly around the handle to fill the between the handle and the wall of the opening of the tool.

Because of the viscosity of the potting compound and the relatively narrow passage through which it must flow upwardly, air bubbles may be trapped ahead of the handle as it moves downwardly within the opening. These air bubbles may create voids of imperfect and incomplete bonding. The handle and/or the air bubbles may also push the potting compound out of the opening and cause it to splash over the side. This results in a short fill, in which there is insufficient potting compound to effect a reliable and/or complete bond.

It has been found that almost all of these problems can be avoided if the handle is moved into the tool head opening at an extremely slow rate during the latter part of its movement. The ideal assembly technique comprises utilizing a relatively rapid stroke for the first portion of insertion of the handle into the opening and a relatively slow stroke as the handle nears the bottom of the opening where it is acting as a hydraulic ram on the potting compound.

If the bonding between the tool head and handle is imperfect, it may result in separation of the tool head from the handle. If such separation should occur during use of the tool, permanent injury might result, with possible substantial financial liability for the manufacturer of the tool.

At the present time, the potting compound is customarily poured into the end of the opening opposite the handle, relying on gravity and hoping that the potting compound will flow around the shaft into all of the available spaces. This method is often not completely successful. Because the tool head eye opening is completely covered, it is impossible for anyone to tell by external examination whether or not there is a perfect bond between the interior of the opening and the exterior of the handle. Hidden air pockets or a short fill of potting compound are likely to occur, with a resulting incomplete bonding which can result in serious injury when the tool is placed in use.

The dominant reason present methods of assembly are unsatisfactory is the lack of complete safety. There is no practical means for determining whether there is a full charge of potting compound properly distributed in the hidden tool opening, even when a full charge has been loaded. If any portion of the potting compound is splashed or forced outside the assembly, the attachment is degraded and there is danger that the head will come off in use and cause injury. Tool assemblies must have zero defects. Even one faulty assembly in thousands may cause a critical injury.

Present methods of assembly also customarily require an operator to attach only one handle at a time, making the assembly a costly operation to the manufacturer in terms of the labor time required. Present equipment also requires relatively highly skilled labor to perform the assembly operation.

Since existing methods are often unsatisfactory, there is costly waste of labor and material resulting from the production of unacceptable finished products.

SUMMARY OF THE INVENTION The present invention avoids the above problems by providing an apparatus in which the speed of insertion of the handle is controlled automatically, so that there are no failures due to variations resulting from human physical and/or mental activities.

The present invention also provides an apparatus in which the speed of insertion of the handle is varied in such a manner that the initial insertion is rapid, which is desirable for speed of assembly and which is permissible because there is no likelihood of undesirable squirting of the compound occurring during the initial portion of the insertion. The potting compound is at that time disposed within the lower portion of the tool head opening and is not yet engaged by the handle. The speed of insertion is then progressively and automatically reduced as the insertion is completed. The speed of insertion is at a relative minimum at the point where the end of the handle engages the potting compound and displaces it into the free spaces within the tool head opening. This is the time when likelihood of squirting is greatest and when slowest displacement of the potting compound is desirable in order to move it into the free spaces without creating voids of entrapped air. Such voids and spillage of potting compound are most likely to occur from too rapid movement of the handle into the potting compound.

It is accordingly among the objects of the present invention to provide an apparatus for attaching tool handles and similar bonding operations having all of the advantages and benefits set forth above and described in detail hereinafter in this specification.

It is a more particular object of the invention to provide an apparatus of the type described which is automatic in operation, which provides substantially perfect and foolproof bonding of every handle and in which the speed of insertion of the handle is the most desirable speed for each particular stage of the assembly operation.

Another object of the invention is to provide such an apparatus with which a single unskilled operator can assemble a plurality of tools at the same time, thus reducing both the quantity and the quality of labor required.

It is a further object of the invention to provide such an apparatus which is relatively simple and inexpensive to manufacture and simple to operate.

The invention also comprises such other objects, advantages, and capabilities as will later more fully appear and which are inherently possessed by the invention.

While there is shown in the accompanying drawings a preferred embodiment of the invention, it should be understood that the same is susceptible of modification and change without departing from the spirit of the invention.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevational view of the apparatus in use;

FIG. 2 is a side elevational view of the same;

FIG. 3 is an enlarged mostly sectional view of the device used to hold the end of the handle;

FIG. 4 is an enlarged front elevational view of the assembly used to hold the portion of the handle adjacent to the tool head; with the hammer omitted;

FIG. 5 is an enlarged front elevational view showing a handle being inserted into a tool head, with the midportion of the tool head broken away and shown in section;

FIG. 6 is a view similar to FIG. 5, showing the handle fully inserted within the tool head opening.

DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment which has been selected to illustrate the invention comprises a panel 10. Rotatably mounted on the upper portion of the panel 10 are four intermeshed gear wheels 11-14 respectively. The gear wheel 14 is mounted on a shaft 15 which extends through the panel 10. The shaft 15 is connected to and driven by a chain 16, which is in turn connected to and driven by an electric motor 17. The motor 17 is mounted on a plate 18 disposed behind the panel 10.

Pivotally attached to the gear wheels 11-14 outwardly from the center thereof are the upper ends of four arms 19-22 respectively. Pivotally connected to the lower ends of the arms 19-22 are four rods 23-26 respectively. Mounted on the lower ends of the rods 23-26 are four cup members 27-30 respectively. The rods 23-26 are mounted for sliding reciprocal vertical movement through a pair of vertically spaced

guide members

31 and 32, which hold the rods 23-26 in proper vertical alignment during their movement.

All of the cup members 27-30 are identical in their structure, which is best shown in FIG. 3 of the drawings. As shown, the cup member 27 has at its lower end a frusto-conical hollow cup 58, which is adapted to fit around and hold the upper end of a hammer or other tool or article. A coil spring 59 extends between the upper end of the cup 48 and a disc 60 which is connected to the lower end of the rod 23. The disc 60 is free to move downwardly within the cup member 27 against the pressure of the coil spring 59. A stop member 61 limits upward movement of the disc 60.

Mounted on the lower portion of the panel 10 are four handle holding members 35. All of the handle holding members 35 are identical in structure, as best shown in FIG. 4 of the drawings. As illustrated, the handle holding member 35 has mounted adjacent its upper portion a stationary retaining member 36 and a pivotable retaining member 37 which is mounted for pivotal movement about a fastening member 38 extending through its lower portion, as indicated by phantom lines in FIG. 4. A coil spring 39 extends between the two retaining

members

36 and 37 and normally urges the pivotable retaining member 37 into a vertical position. A stop member 40 which projects outwardly from the pivotable retaining member 37 acts to limit its movement toward the stationary retaining member 36.

The retaining

members

36 and 37 have

circular members

45 and 46 respectively mounted adjacent their upper portions. The

circular members

45 and 46 are undercut and radiused at 47 and 48 as indicated by the dotted lines in FIGS. 4 and 5 of the drawings. As shown in FIG. 5, the sides of a tool handle fit behind the

undercut portions

47 and 48. The

circular members

45 and 46 accordingly act to prevent movement of the handle away from the panel 10.

Referring to FIG. 1 of the drawings, it will be seen that this embodiment of the invention is adapted to handle four tools at a time. In order to simplify insertion and removal of the tools or other work articles, the connections between the upper ends of the arms 19-22 and the gear wheels 11-14 are preferably 90 out of phase with each other. This means that only one assembly unit at a time completes its stroke, so that the tool can be removed and a new one inserted.

In FIG. 1, the assembly unit which includes the gear wheel 13 has completed its stroke, the assembled tool has been removed and a new tool is in place. Rotational movement of the wheel 13 in a counter-clockwise direction will cause downward movement of the arm 21 and rod 25, causing the hollow cup of the cup member 29 to move downwardly and fit around and hold the upper end of the tool 71.

The adjacent gear wheel 14 moves in a clockwise direction and is in rapid downward movement in the position shown in FIG. 1. The handle 74 is partially inserted into the tool head 75 and is in the process of further insertion. The gear wheel 11 is at the halfway point of its stroke, with the handle 72 of the tool being fully driven into position within the tool head 73. Upon further clockwise rotation of the gear wheel 11, its cup member 27 will move upwardly.

The gear wheel 12 is at the halfway point in its upper movement after completion of its downward movement. The tool has been omitted from the illustration. If a tool were in place, it would be fully assembled and would be ready for removal upon further upward movement of the cup member 28.

It will be seen that the vector of vertical force or movement of the cup members 27-30 varies with the rotation of the gear wheels 1 1-14. For simplicity of explanation, the areas of positioning and movement of the connections between the upper ends of the arms 19-22 and the gear wheels 11-14 may be divided into four quadrants of a compass. Using the top as north, the top quadrant would extend between northeast and northwest. In this quadrant, vertical force or movement of the arms, rods and cup members is at a minimum. This simplifies insertion and removal of the tools, which occurs when the gear wheels 11-14 are moving within this top quadrant.

The side quadrants, which extend between northeast and northwest on one side and between southeast and southwest on the other side, are the quadrants of maximum vertical movement. This movement may be in an upward or downward direction, depending upon the direction of rotation of the gear wheel. The point of maximum vertical movement is reached at the point of east or west.

The fourth quadrant, which extends between southeast and southwest, is an area of reduced vertical movement, the speed of which progressively slows and is reduced to zero at the point of south.

Using the gear wheel 14 as an example, it will be seen that the rate of downward movement is at a maximum when the gear wheel 14 is in the position shown in the drawings. The handle is then only partially inserted and its lower end does not yet engage the potting compound within the tool head opening, so there is no danger of spillage.

From the position shown, the rate of downward movement of the tool handle progressively decreases to reach zero at the bottom or south point. During the critical last fraction of an inch when the lower end of the handle engages the potting compound and forces it upwardly within the tool head opening, the handle is moving at its minimum rate of downward movement. For the reasons set forth above, this reduces the likelihood of spillage and increases the likelihood of achieving complete bonding between the handle and tool head.

It will be seen that the apparatus of the present invention provides the ideal assembly technique desired. It provides rapid movement of the handle during the first part of the insertion and then progressively slower movement during the final part of the insertion.

Referring to FIG. 5 of the drawings, this illustration shows the lower end of a tool handle 90 about to be inserted into a tool head eye opening 91 within a tool head 92. A resilient insert 93 is used to hold the handle 90 stationary and in proper position during curing of the potting compound. An end plug 94 is used for appearance purposes. A piece of masking tape 96 closes off the lower end of an eye opening 91 so that potting compound will not flow out of the opening 91. The potting compound has been omitted from the illustration.

FIG. 6 of the drawings shows the handle 90 fully inserted into the opening 91. The potting compound has been omitted, but it would fill all of the spaces within the opening 91 not filled by the handle 90, insert 93 and end plug 94.

When a tool is inserted by movement toward the panel 10, its handle engages the circular member 46 of the pivotable retaining member 37 and causes it to pivot in a clockwise direction against the urging of the coil spring 39, permitting the handle of the tool to pass between the

circular members

45 and 46. The pivotable retaining member 37 is then returned to its normal vertical position by the coil spring 39 and the handle is held behind the

undercut portions

47 and 48. A rod 95 which extends horizontally across the midportion of the panel acts to limit movement of the tool handles toward the panel 10.

With regard to the cup members 27-30, they act to provide a resilient connection between the rods 23-26 and the tool handle also. The coil springs 59 are adapted to flex, to compensate for unusual variations in the vertical length of the tool handles which might otherwise cause jamming and damage to the machine.

As best shown in FIG. 2 of the drawings, each of the

circular members

45 and 46 has a configuration somewhat resembling that of a spool. The front and back edgesare straight, while the portion between comprises the undercut 47 or 48, which is preferably curved inwardly or otherwise formed complementarily to the contour of the portion of the handle which it engages.

I claim:

1. An apparatus for making a fiberglass connection of the type-in which one end of an elongated handle is mounted in an opening in a tool head, said apparatus comprising a rotatably mounted wheel, a member adapted to engage the upper end of an elongated vertically directed handle disposed beneath said member, means connecting said member to said wheel for reciprocal vertical movement of said member upon rotation of said wheel, means for disposing a tool head having a handle receiving opening beneath said handle with said opening aligned with said handle, said opening being adapted to hold a charge of potting compound, said member and handle being movable vertically downwardly upon rotational movement of said wheel to move the lower end of said handle into said opening, the downward movement of said handle being progressively slower as the lower end of said handle moves toward the bottom of said opening and engages the potting compound therein, whereby said potting compound is slowly displaced upwardly substantially evenly around and between all of the inner walls of said opening and the adjacent sides of said handle to form a bond between said handle and tool head.

2. The structure described in claim 1, and means for holding a handle in a vertically directed position between said member and said tool head for vertical downward movement into said tool head.

3. The structure described in claim 2, said means connecting said member to said wheel including an arm pivotally connected at its upper end to said wheel, said arm being connected to said member.

4. The structure described in claim 3, said means connecting said member to said wheel including a rod pivotally connected at its upper end to the lower end of said arm, said rod being pivotally connected at its lower end to said member, and means mounting said rod for reciprocal vertical movement upon the rotation of said wheel.

5. The structure described in claim 4, said apparatus including a plurality of wheels having intermeshing gears for rotation of all of said wheels simultaneously.

6. The structure described in claim 5, said apparatus including four wheels for mounting four handles simultaneously, the rotational movement of said wheels and the downward vertical movement of said handles being substantially out of phase with each other.

7. The structure described in claim 6, each of said members comprising a downwardly directed cup adapted to fit around the upper end of a handle and spring means urging said cup toward said handle, said spring means adapted to yield to prevent damage to said apparatus due to variations in the lengths of handles.

8. The structure described in claim 7, said means for holding said handle in a vertically directed position comprising a pair of circular members, at least one of which is mounted for yielding movement away from the other, said circular members being adapted to removably engage the sides of the handle.

9. The structure described in claim 8, and electrically operated drive means connected to one of said wheels for rotation thereof, the remainder of said wheels being rotated simultaneously by their inner engagement with the driven wheel.

10. The structure described in claim 9, said handle holding means comprising a stationary retaining member and a pivotable retaining member mounted for pivotal movement away from said stationary member, resilient means for normally holding said pivotable mem-

Claims

1. An apparatus for making a fiberglass connection of the type in which one end of an elongated handle is mounted in an opening in a tool head, said apparatus comprising a rotatably mounted wheel, a member adapted to engage the upper end of an elongated vertically directed handle disposed beneath said member, means connecting said member to said wheel for reciprocal vertical movement of said member upon rotation of said wheel, means for disposing a tool head having a handle receiving opening beneath said handle with said opening aligned with said handle, said opening being adapted to hold a charge of potting compound, said member and handle being movable vertically downwardly upon rotational movement of said wheel to move the lower end of said handle into said opening, the downward movement of said handle being progressively slower as the lower end of said handle moves toward the bottom of said opening and engages the potting compound therein, whereby said potting compound is slowly displaced upwardly substantially evenly around and between all of the inner walls of said opening and the adjacent sides of said handle to form a bond between said handle and tool head.

6. The structure described in claim 5, said apparatus including four wheels for mounting four handles simultaneously, the rotational movement of said wheels and the downward vertical movement of said handles being substantially 90* out of phase with each other.

10. The structure described in claim 9, said handle holding means comprising a stationary retaining member and a pivotable retaining member mounted for pivotal movement away from said stationary member, resilient means for normally holding said pivotable member toward said stationary member, said circular members being mounted on said retaining members, each of said circular members having an undercut portion of lesser diameter than the outer peripheral portion thereof, said undercut portion being adapted to engage and hold the side of a handle.