CA1078229A - Screwdriver and screw for use therewith - Google Patents
Screwdriver and screw for use therewithInfo
- Publication number
- CA1078229A CA1078229A CA262,005A CA262005A CA1078229A CA 1078229 A CA1078229 A CA 1078229A CA 262005 A CA262005 A CA 262005A CA 1078229 A CA1078229 A CA 1078229A
- Authority
- CA
- Canada
- Prior art keywords
- tip
- slot
- screwdriver
- screw
- bore
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
- B25B15/00—Screwdrivers
- B25B15/001—Screwdrivers characterised by material or shape of the tool bit
- B25B15/004—Screwdrivers characterised by material or shape of the tool bit characterised by cross-section
- B25B15/007—Screwdrivers characterised by material or shape of the tool bit characterised by cross-section with blade of flat or substantially flat cross-section
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B23/00—Specially shaped nuts or heads of bolts or screws for rotations by a tool
- F16B23/0007—Specially shaped nuts or heads of bolts or screws for rotations by a tool characterised by the shape of the recess or the protrusion engaging the tool
- F16B23/0015—Specially shaped nuts or heads of bolts or screws for rotations by a tool characterised by the shape of the recess or the protrusion engaging the tool substantially rectangular, e.g. one-slot head
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B23/00—Specially shaped nuts or heads of bolts or screws for rotations by a tool
- F16B23/0007—Specially shaped nuts or heads of bolts or screws for rotations by a tool characterised by the shape of the recess or the protrusion engaging the tool
- F16B23/0023—Specially shaped nuts or heads of bolts or screws for rotations by a tool characterised by the shape of the recess or the protrusion engaging the tool substantially cross-shaped
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Details Of Spanners, Wrenches, And Screw Drivers And Accessories (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The specification describes an improved screw-driver and screw constructed in such a manner that the two are maintained in proper alignment during use and so that the screw may be held on the end of the screwdriver without the use of one's hand. The screwdriver is formed with an axial projection at its tip which is adapted to be received in an axial bore in the head portion of the screw.
To grip the screw to the screwdriver, the projection and bore are constructed so that there exists an interference, tapered fit when the driver and screw are drivingly engaged.
The specification describes an improved screw-driver and screw constructed in such a manner that the two are maintained in proper alignment during use and so that the screw may be held on the end of the screwdriver without the use of one's hand. The screwdriver is formed with an axial projection at its tip which is adapted to be received in an axial bore in the head portion of the screw.
To grip the screw to the screwdriver, the projection and bore are constructed so that there exists an interference, tapered fit when the driver and screw are drivingly engaged.
Description
1~78ZZ9 The present invention is directed to a device for maintaining axial alignment between a rotatable driving member and a driven member and, also, to such a device which will tend to resist axial separation of the driving and driven members once they are operably engaged. More specifically, the invention is airected to a device of this nature used in conjunction with a screwdriver and screw fasteners.
Screw fasteners are made in many forms such as wood screws, metal screws, machine screws, bolts and the like.
- These have various types of heads and threads but all require some means of applying torque for tightening and loosening.
These vary from square or hexagon heads for use with a wrench to the common slotted head used on wood screws. ~he ; slotted head is the most common in the smaller sizes.
In the slotted head type of screw, torque is applied through a straight sided, flat bit screwdriver, normally referred to as a standard screwdriver. This system has worked well for many years and is stili in general use despite many attempts at improvement.
; The most serious faults of the slot system are that the screwdriver must be kept in proper axial a~ignment with the screw to prevent the bit from slipping out of the slot and damaging the driving surfaces and that the screw must , be held at the start which requires the use of two hands by the user. In many instances, it is not possible to initially hold the screw thereby renderlng the driving of the screw j rather difficult.
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~ 1078ZZ9 As indicated, various attempts at improvement have been made. These usually involve socket type recesses in the screw head combined with a specially shaped driver.
The screwdriver type known by the "Robertson"(Trade Mark) uses a tapered square socket while the type known by the "Phillips"(Trade Mark)uses a tapered cruciform socket and there are several others. All of these su~fer from the fact that the socket must be small enough to prevent excessive weakening of the screw head and the driving surfaces are therefore close to the axis of the screw. This means that large forces relative to those of a standard screwdriver must be applied to the driving surfaces in order to obtain adequate torque frequently resulting in distortion or even practical destruction of the sockets in the driven member.
The tapered socket and matching driver do give some screw holding ability but these are not reliable since the high driving forces tend to distort the socket and destroy the gripping action. The taper on the driving surfaces also tends to force the driver out of engagement causing slipping and damage to the screw socket and driver driving surfaces.
This makes subsequent unfastening difficult or impossible.
The slotted head type of screw used in conjunction with the standard screwdriver is probably the best method , of transmitting torque since it can be applied at t,he outer .
limits of the screw head. This permits application of smaller forces to achieve adequate torque. The alignment problem can be solved by providinq an axial bore in the screw head and a mating axial pin in the driver bit. This was disclosed in . . .
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`` ~078~29 U.S. Patent No. 105,606 by H.A. Johnston however his method did not provide any screw retaining feature since the bore in the screw was specified as cylindrical and the mating pin as a loose fit in the bore.
The solution to the problems of torque application, centering and screw retention can best be solved by separating the functions and providing separate surfaces for torque appli-cation and centering and screw retention. This is achieved by providing one or more straight sided slots across the head of the screw in combination with a straight sided driver bit for torque application only. Combined with the above, a tapered central bore is provided in the screw head which acts with a mating tapered pin in the driver to provide centering and frictional screw retaining action. The centering and screw retaining surfaces do not transmit any appreciable torque and are therefore not subject to distortion and do not cause "camming out" problems.
Thus, the present invention is defined as a screwdriver and screw fastener combination, comprising: a screw fastener having a head portion and a thread portion, a slot in the end of the head portion remote from the thread portion for receiving the tip of the screwdriver and an axial, frusto-conical blind bore in the end portion opening in the end, the slot extending diametrally of the head portion, the slot having a length dimension and a width dimension, the length dimension being equal to the diameter of the head portion;
a screwdriver having a flat blade driving tip for driving engagement with the slot, the tip having a length dimension and a width dimension;
the length dimension being substantially the same as the length 28 dimension of the slot and the width dimension being slightly smaller rw/~
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than the width dimension of the slot so as to define a clearance between the tip and the slot when the tip is located in the slot, and an axial, frusto-conical projection formed of a compressively resilient material extending beyond the tip for reception in the bore, the projection and the bore being dimensioned so as to form an interference fit when the tip is located in the slot whereby the projection is elastically compressed in the bore when the tip is located in the slot, the projection and the bore being exclusively effective to maintain axial alignment between and resist seperation of the screw fastener from the screwdriver tip and the tip and the slot being exclusively effective to transmit torque between the screwdriver and screw fastener.
These and other details of the invention will become clear from the description which follows in which reference is made to the appended drawings wherein:
Figure 1 is a front elevational view of a screwdriver blade tip illustrating one embodiment of the present invention;
Figure 2 is a side view of the screwdriver illustrated in Figure l;
Figure 3 is a partial cross-sectional view of a screw fastener used in conjunction with the screwdriver blade tips illustrated in Figures 1, 2, 5 and 6;
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Figure 4 is a top view of the screw fastener illustrated in Figure 3; and, Figures 5 and 6 are perspective views of alternative screwdriver blade tip constructions.
Reference will now be made to Figures 1 to 4. Figures 1 and 2 illustrate one embodiment of a screwdriver generally - designated by reference numeral 10. Screwdriver 10 is basically of the standard type having a blade 11 and blade tip 12. Blade tip 12 is formed with substantially parallel opposed driving surfaces 18 and 19 and transverse end surface 16. Tip 12 is formed with a blind bore 13 adapted to partially receive one end of a pilot pin 15 as shown. Pin 15 may be securely held in bore 13 in any suitable manner such as, for example, an interference fit, an adhesive or by a transverse pin (not shown) or the pin could be forged as part of the blade. The other end of pin 15 projects beyond the extreme end 16 of blade tip 12. The outer projection of pin 15 is shown to be formed with a slight taper to provide a gripping eorce which wilI be described later.
The screw fastener Z0 used in conjunction with the aforedescribed blade tip is illustrated in Figures 3 and 4.
It is seen to be comprised of a head portion 21 and a thread portion 22. Head portion 21 is formed with a conventional slot 24 which extends diametrically of the axis of the screw.
The slot has the usual parallel opposed surfaces 25 and 26 adapted to engage the parallel opposed driving surfaces 18 and 19 of blade tip 12 for the transference of a torque. The head 21 is also formed with an axial blind hole or bore 30 adapted to recei~e the outer projection of pin 15.
lir: lc . ' -: .
' ` 1C)782;~9 It ha.c been found that-a pin of circular cross-section and tapered as shown will be more readily received in a bore similarly tapered.
As mentioned earlier, in hard to reach areas, it is often desirable to be able to insert the screw upon the end of the blade tip and have it held there without the use of one's hand. This can be easily effected by providing a slight interference fit between pin lS and bore 30 when the blade tip is positioned for transferring torque. Thus, the interference fit will provide a frictional force which will tend to resist separation of the projection from the bore. In this manner,, the screw may be mounted onto the end of the blade tip and aligned with the threaded hole with which it is to be received with the use of one hand only even in the vertical down position.
Again, it will be appreciated that the screwdriver and screw will be more easily aligned and engaged if the projection is tapered.
Thus, an improved torque transferring device is provided which combines the desirable torque transmitting characteristics of the standard type screwdriver and slot head screw and the alignability of the "Robertson" (Trade Mark) and "Phillips" (Trade Mark) screwdrivers and screws.
The provision of the interference, tapered connection enables the screw head to be frictionally received at the end of the blade tip and held there without the use of one's hands.
Figures 5 and 6 show secondary features of the invention. In Figure S, the blade tip 12 is cylindrical in l~r~
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shape with a circular end face 17 adapted to bear against the flat face of the head portion of the screw. This configura-tion assists in maintaining alignment of the screw and screw-driver.
In Figure 6, an additional set of driving surfaces 18' and 19' disposed perpendicularly to the first set of surfaces 18 and 19 are provided. The additional driving surfaces will tend to reduce the contact forces and thereby prolong the life of the screwdriver and screw and minimize damage thereto. This also provides maximum stability for the screw when held on the driver even with round headed screws.
In the tapered pilot pin embodiments, the degree of taper should be optimized to provide ease of entry of the pilot pin in the blind bore of the screw combined with adequate friction force for screw retention.
The degree of taper required for frictional engagement is determined by the coefficient of friction of the two mating surfaces. Some typical coefficients are as follows:
Delrin on steel - 0.15-0.35 Nylon on steel - 0.15-0.40 High density Polyethylene on steel - 0.21 Steel on steel - Q.15 The coefficient of static friction is the tangent of the angle of repose between two bodies below which self sliding will not occur. The angle whose tangent is 0.15 is approximately 8 - 30~. This would indicate that the included angle of taper on the pin should not exceed 17. Ideally the taper should be -` the minimum that will allo~ easy entry of the pin into the ;~ , .
l~r:jc ,, ' 107822g screw socket without introducing difficulties in manufacture.
A taper angle of 9 - 30~ or 1 in 12 would seem to be practical.
This is slightly larger than the taper commonly used in machine tools.
The pilot pin may be made of materials such as those known by the trade marks delrin, nylon, polyethylene, as well as, steel. The synthetic materials mentioned above will have a tendency to deform slightly resulting in improved gripping 9 action.
- , ~ . , . .
. . . .... .
.
~ - .
Screw fasteners are made in many forms such as wood screws, metal screws, machine screws, bolts and the like.
- These have various types of heads and threads but all require some means of applying torque for tightening and loosening.
These vary from square or hexagon heads for use with a wrench to the common slotted head used on wood screws. ~he ; slotted head is the most common in the smaller sizes.
In the slotted head type of screw, torque is applied through a straight sided, flat bit screwdriver, normally referred to as a standard screwdriver. This system has worked well for many years and is stili in general use despite many attempts at improvement.
; The most serious faults of the slot system are that the screwdriver must be kept in proper axial a~ignment with the screw to prevent the bit from slipping out of the slot and damaging the driving surfaces and that the screw must , be held at the start which requires the use of two hands by the user. In many instances, it is not possible to initially hold the screw thereby renderlng the driving of the screw j rather difficult.
- l~r:~, ' . ,.................................... ' : ~ ~:
:~ . ' ' . ., , .' ~ :
.
.
,~ :
~ 1078ZZ9 As indicated, various attempts at improvement have been made. These usually involve socket type recesses in the screw head combined with a specially shaped driver.
The screwdriver type known by the "Robertson"(Trade Mark) uses a tapered square socket while the type known by the "Phillips"(Trade Mark)uses a tapered cruciform socket and there are several others. All of these su~fer from the fact that the socket must be small enough to prevent excessive weakening of the screw head and the driving surfaces are therefore close to the axis of the screw. This means that large forces relative to those of a standard screwdriver must be applied to the driving surfaces in order to obtain adequate torque frequently resulting in distortion or even practical destruction of the sockets in the driven member.
The tapered socket and matching driver do give some screw holding ability but these are not reliable since the high driving forces tend to distort the socket and destroy the gripping action. The taper on the driving surfaces also tends to force the driver out of engagement causing slipping and damage to the screw socket and driver driving surfaces.
This makes subsequent unfastening difficult or impossible.
The slotted head type of screw used in conjunction with the standard screwdriver is probably the best method , of transmitting torque since it can be applied at t,he outer .
limits of the screw head. This permits application of smaller forces to achieve adequate torque. The alignment problem can be solved by providinq an axial bore in the screw head and a mating axial pin in the driver bit. This was disclosed in . . .
,, - 2 -. ' l~r:,~c -- . ~ , ~, . . . .
- , . . ...
:, . ~ - - :
, . :
. . . ~ .
~ . :
.. .
.
`` ~078~29 U.S. Patent No. 105,606 by H.A. Johnston however his method did not provide any screw retaining feature since the bore in the screw was specified as cylindrical and the mating pin as a loose fit in the bore.
The solution to the problems of torque application, centering and screw retention can best be solved by separating the functions and providing separate surfaces for torque appli-cation and centering and screw retention. This is achieved by providing one or more straight sided slots across the head of the screw in combination with a straight sided driver bit for torque application only. Combined with the above, a tapered central bore is provided in the screw head which acts with a mating tapered pin in the driver to provide centering and frictional screw retaining action. The centering and screw retaining surfaces do not transmit any appreciable torque and are therefore not subject to distortion and do not cause "camming out" problems.
Thus, the present invention is defined as a screwdriver and screw fastener combination, comprising: a screw fastener having a head portion and a thread portion, a slot in the end of the head portion remote from the thread portion for receiving the tip of the screwdriver and an axial, frusto-conical blind bore in the end portion opening in the end, the slot extending diametrally of the head portion, the slot having a length dimension and a width dimension, the length dimension being equal to the diameter of the head portion;
a screwdriver having a flat blade driving tip for driving engagement with the slot, the tip having a length dimension and a width dimension;
the length dimension being substantially the same as the length 28 dimension of the slot and the width dimension being slightly smaller rw/~
: ~ , .~' ' . , . , .
.
1~78~:~9 ,~ .
than the width dimension of the slot so as to define a clearance between the tip and the slot when the tip is located in the slot, and an axial, frusto-conical projection formed of a compressively resilient material extending beyond the tip for reception in the bore, the projection and the bore being dimensioned so as to form an interference fit when the tip is located in the slot whereby the projection is elastically compressed in the bore when the tip is located in the slot, the projection and the bore being exclusively effective to maintain axial alignment between and resist seperation of the screw fastener from the screwdriver tip and the tip and the slot being exclusively effective to transmit torque between the screwdriver and screw fastener.
These and other details of the invention will become clear from the description which follows in which reference is made to the appended drawings wherein:
Figure 1 is a front elevational view of a screwdriver blade tip illustrating one embodiment of the present invention;
Figure 2 is a side view of the screwdriver illustrated in Figure l;
Figure 3 is a partial cross-sectional view of a screw fastener used in conjunction with the screwdriver blade tips illustrated in Figures 1, 2, 5 and 6;
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: . . . - . ~ . : . .
Figure 4 is a top view of the screw fastener illustrated in Figure 3; and, Figures 5 and 6 are perspective views of alternative screwdriver blade tip constructions.
Reference will now be made to Figures 1 to 4. Figures 1 and 2 illustrate one embodiment of a screwdriver generally - designated by reference numeral 10. Screwdriver 10 is basically of the standard type having a blade 11 and blade tip 12. Blade tip 12 is formed with substantially parallel opposed driving surfaces 18 and 19 and transverse end surface 16. Tip 12 is formed with a blind bore 13 adapted to partially receive one end of a pilot pin 15 as shown. Pin 15 may be securely held in bore 13 in any suitable manner such as, for example, an interference fit, an adhesive or by a transverse pin (not shown) or the pin could be forged as part of the blade. The other end of pin 15 projects beyond the extreme end 16 of blade tip 12. The outer projection of pin 15 is shown to be formed with a slight taper to provide a gripping eorce which wilI be described later.
The screw fastener Z0 used in conjunction with the aforedescribed blade tip is illustrated in Figures 3 and 4.
It is seen to be comprised of a head portion 21 and a thread portion 22. Head portion 21 is formed with a conventional slot 24 which extends diametrically of the axis of the screw.
The slot has the usual parallel opposed surfaces 25 and 26 adapted to engage the parallel opposed driving surfaces 18 and 19 of blade tip 12 for the transference of a torque. The head 21 is also formed with an axial blind hole or bore 30 adapted to recei~e the outer projection of pin 15.
lir: lc . ' -: .
' ` 1C)782;~9 It ha.c been found that-a pin of circular cross-section and tapered as shown will be more readily received in a bore similarly tapered.
As mentioned earlier, in hard to reach areas, it is often desirable to be able to insert the screw upon the end of the blade tip and have it held there without the use of one's hand. This can be easily effected by providing a slight interference fit between pin lS and bore 30 when the blade tip is positioned for transferring torque. Thus, the interference fit will provide a frictional force which will tend to resist separation of the projection from the bore. In this manner,, the screw may be mounted onto the end of the blade tip and aligned with the threaded hole with which it is to be received with the use of one hand only even in the vertical down position.
Again, it will be appreciated that the screwdriver and screw will be more easily aligned and engaged if the projection is tapered.
Thus, an improved torque transferring device is provided which combines the desirable torque transmitting characteristics of the standard type screwdriver and slot head screw and the alignability of the "Robertson" (Trade Mark) and "Phillips" (Trade Mark) screwdrivers and screws.
The provision of the interference, tapered connection enables the screw head to be frictionally received at the end of the blade tip and held there without the use of one's hands.
Figures 5 and 6 show secondary features of the invention. In Figure S, the blade tip 12 is cylindrical in l~r~
: .. , :
.
- . . : : - .
: . ,. . . , - ~ :
: . : .
~ . . . .
shape with a circular end face 17 adapted to bear against the flat face of the head portion of the screw. This configura-tion assists in maintaining alignment of the screw and screw-driver.
In Figure 6, an additional set of driving surfaces 18' and 19' disposed perpendicularly to the first set of surfaces 18 and 19 are provided. The additional driving surfaces will tend to reduce the contact forces and thereby prolong the life of the screwdriver and screw and minimize damage thereto. This also provides maximum stability for the screw when held on the driver even with round headed screws.
In the tapered pilot pin embodiments, the degree of taper should be optimized to provide ease of entry of the pilot pin in the blind bore of the screw combined with adequate friction force for screw retention.
The degree of taper required for frictional engagement is determined by the coefficient of friction of the two mating surfaces. Some typical coefficients are as follows:
Delrin on steel - 0.15-0.35 Nylon on steel - 0.15-0.40 High density Polyethylene on steel - 0.21 Steel on steel - Q.15 The coefficient of static friction is the tangent of the angle of repose between two bodies below which self sliding will not occur. The angle whose tangent is 0.15 is approximately 8 - 30~. This would indicate that the included angle of taper on the pin should not exceed 17. Ideally the taper should be -` the minimum that will allo~ easy entry of the pin into the ;~ , .
l~r:jc ,, ' 107822g screw socket without introducing difficulties in manufacture.
A taper angle of 9 - 30~ or 1 in 12 would seem to be practical.
This is slightly larger than the taper commonly used in machine tools.
The pilot pin may be made of materials such as those known by the trade marks delrin, nylon, polyethylene, as well as, steel. The synthetic materials mentioned above will have a tendency to deform slightly resulting in improved gripping 9 action.
- , ~ . , . .
. . . .... .
.
~ - .
Claims (3)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A screwdriver and screw fastener combination, comprising:
a screw fastener having a head portion and a thread portion, a slot in the end of said head portion remote from said thread portion for receiving the tip of said screwdriver and an axial, frusto-conical blind bore in said end portion opening in said end, said slot extending diametrally of said head portion, said slot having a length dimension and a width dimension; said length dimension being equal to the diameter of said head portion;
a screwdriver having a flat blade driving tip for driving engagement with said slot, said tip having a length dimension and a width dimension; said length dimension being substantially the same as the length dimension of said slot and said width dimension being slightly smaller than the width dimension of said slot so as to define a clearance between said tip and said slot when said tip is located in said slot, and an axial, frusto-conical projection formed of a compressively resilient material extending beyond said tip for reception in said bore, said projection and said bore being dimensioned so as to form an interference fit when said tip is located in said slot whereby said projection is elastically compressed in said bore when said tip is located in said slot;
said projection and said bore being exclusively effective to maintain axial alignment between and resist separation of said screw fastener from said screwdriver tip and said tip and said slot being exclusively effective to transmit torque between said screwdriver and screw fastener.
a screw fastener having a head portion and a thread portion, a slot in the end of said head portion remote from said thread portion for receiving the tip of said screwdriver and an axial, frusto-conical blind bore in said end portion opening in said end, said slot extending diametrally of said head portion, said slot having a length dimension and a width dimension; said length dimension being equal to the diameter of said head portion;
a screwdriver having a flat blade driving tip for driving engagement with said slot, said tip having a length dimension and a width dimension; said length dimension being substantially the same as the length dimension of said slot and said width dimension being slightly smaller than the width dimension of said slot so as to define a clearance between said tip and said slot when said tip is located in said slot, and an axial, frusto-conical projection formed of a compressively resilient material extending beyond said tip for reception in said bore, said projection and said bore being dimensioned so as to form an interference fit when said tip is located in said slot whereby said projection is elastically compressed in said bore when said tip is located in said slot;
said projection and said bore being exclusively effective to maintain axial alignment between and resist separation of said screw fastener from said screwdriver tip and said tip and said slot being exclusively effective to transmit torque between said screwdriver and screw fastener.
2. A combination as defined in Claim 1, said tip having a second flat blade driving tip disposed perpendicularly to the first mentioned flat blade driving tip and said head portion having a second diametral slot disposed perpen-dicularly of said first mentioned slot for engagement with said second driving tip.
3. A combination as defined in claim 1, or 2, wherein said material is selected from the group known by the trade marks delrin, nylon and polyethylene.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA262,005A CA1078229A (en) | 1976-09-24 | 1976-09-24 | Screwdriver and screw for use therewith |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA262,005A CA1078229A (en) | 1976-09-24 | 1976-09-24 | Screwdriver and screw for use therewith |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1078229A true CA1078229A (en) | 1980-05-27 |
Family
ID=4106929
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA262,005A Expired CA1078229A (en) | 1976-09-24 | 1976-09-24 | Screwdriver and screw for use therewith |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1078229A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1984004481A1 (en) * | 1983-05-06 | 1984-11-22 | John Vaughn | Improved high torque fastener and driving tool |
| US4528874A (en) * | 1983-01-17 | 1985-07-16 | Dunn J Malcolm | Screw fasteners and drivers |
| US4589154A (en) * | 1983-05-06 | 1986-05-20 | John Vaughn | Method and apparatus for forming the head of a high torque fastener |
| US4590825A (en) * | 1983-05-06 | 1986-05-27 | John Vaughn | High torque fastener and driving tool |
| US4670927A (en) * | 1983-05-06 | 1987-06-09 | John Vaughn | Method and apparatus for forming the head of a high torque fastener |
| EP2783733A4 (en) * | 2011-11-25 | 2016-03-09 | Garcia Ricardo Arveras | ACCESSORY FOR FIXING STOP POINTS ON FENCING SPEARS |
| NL2013638B1 (en) * | 2014-10-15 | 2016-10-04 | Univ Delft Tech | Precision screw driver/screw assembly, screw driver and screw. |
-
1976
- 1976-09-24 CA CA262,005A patent/CA1078229A/en not_active Expired
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4528874A (en) * | 1983-01-17 | 1985-07-16 | Dunn J Malcolm | Screw fasteners and drivers |
| WO1984004481A1 (en) * | 1983-05-06 | 1984-11-22 | John Vaughn | Improved high torque fastener and driving tool |
| US4497225A (en) * | 1983-05-06 | 1985-02-05 | John Vaughn | High torque fastener and driving tool |
| US4589154A (en) * | 1983-05-06 | 1986-05-20 | John Vaughn | Method and apparatus for forming the head of a high torque fastener |
| US4590825A (en) * | 1983-05-06 | 1986-05-27 | John Vaughn | High torque fastener and driving tool |
| US4670927A (en) * | 1983-05-06 | 1987-06-09 | John Vaughn | Method and apparatus for forming the head of a high torque fastener |
| EP2783733A4 (en) * | 2011-11-25 | 2016-03-09 | Garcia Ricardo Arveras | ACCESSORY FOR FIXING STOP POINTS ON FENCING SPEARS |
| NL2013638B1 (en) * | 2014-10-15 | 2016-10-04 | Univ Delft Tech | Precision screw driver/screw assembly, screw driver and screw. |
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