KEYBOARD ASSEMBLY FOR ORGAN
United States Patent 3750522
An electronic organ having a piano-type keyboard for playing tones and a button region for playing chords or the like, which is economical to manufacture. The keyboard includes lever-type keys that have recesses in their bottom walls for dropping onto a long thin bar to provide a pivotal mounting, and the organ housing having fingers between groups of twelve keys to limit sideward shifting of the keys. The button region includes a sheet of resilient electrically conductive material with tabs formed therein that are bent to an upward incline, a circuit board with contacts positioned below the tabs, and buttons that can be manually depressed to pushed selected tabs against contacts of the circuit board.
US Patent References:
Electrical musical instrument
Lilja - August 1936 - 2049616
Keyboard for musical instruments
Demuth - May 1949 - 2470148
Tone color assembly for electric organs
Bissonette et al. - March 1957 - 2785238
Switch arrangement for electronic organs
Holt - October 1962 - 3060784
ELECTRONIC ORGAN PRESET AND CANCEL MECHANISM
Thomas et al. - January 1969 - 3420131
Electrical musical instrument
Lilja - August 1936 - 2049616
Keyboard for musical instruments
Demuth - May 1949 - 2470148
Tone color assembly for electric organs
Bissonette et al. - March 1957 - 2785238
Switch arrangement for electronic organs
Holt - October 1962 - 3060784
ELECTRONIC ORGAN PRESET AND CANCEL MECHANISM
Thomas et al. - January 1969 - 3420131
Inventors:
Groves, Sydney L. (Redondo Beach, CA)
La Branche, Harvey W. (Palos Verdes Peninsula, CA)
Cutler, Stanley (Van Nuys, CA)
La Branche, Harvey W. (Palos Verdes Peninsula, CA)
Cutler, Stanley (Van Nuys, CA)
Application Number:
05/303460
Publication Date:
08/07/1973
Filing Date:
11/03/1972
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
984/345, 84/433, 84/720, 84/670
International Classes:
G10H1/34; G10C3/12
Field of Search:
84/1.01,1.17,DIG.7,423,432-441
Primary Examiner:
Wilkinson, Richard W.
Assistant Examiner:
Weldon U.
Parent Case Data:
This is a continuation, of application Ser. No. 98,369, filed Dec. 15, 1970 now abandoned.
Claims:
What is claimed is
1. An organ keyboard comprising:
2. An organ keyboard comprising:
3. An organ keyboard comprising:
4. An organ keyboard comprising:
5. The organ keyboard described in claim 4 wherein:
1. An organ keyboard comprising:
2. An organ keyboard comprising:
3. An organ keyboard comprising:
4. An organ keyboard comprising:
5. The organ keyboard described in claim 4 wherein:
Description:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to electronic organs.
2. Description of the Prior Art
Electronic organs typically include a large number of tone generators that generate electrical signals representing sounds to be played, an amplifier and loudspeaker arrangement for producing audible sounds, and manually operated switches for selectively connecting the tone generators to the amplifier. The switching arrangement typically includes a piano-like keyboard for coupling sounds representing single tones to the amplifier and a button region where sounds representing chords or the like are coupled to the amplifier. Inasmuch as a large number of manually operated switches must be included, an organ construction which provided for simple and easy installed switches would enable economical production and pricing of the organs.
OBJECTS AND SUMMARY OF THE INVENTION
An object of the present invention is to provide an organ keyboard which utilizes a minimum number of parts, and which can be rapidly assembled.
Another object is to provide an electronic organ which is reliable and economical.
In accordance with one embodiment of the present invention, an electronic organ is provided which includes a piano-type keyboard and button switch section, both of which utilize a minimum number of parts and are easy to install. The piano-type keyboard section includes keys which are molded with recesses on their bottom walls for receiving a pivot bar that pivotally supports them on the organ housing, and which are molded with protuberances on one side wall for spacing each key from the next succeeding key. The keys can be installed by merely dropping them over a long pivot bar mounted on the organ, instead of necessitating the projection of a shaft through the keys. Several fingers are mounted on the organ housing beside every twelfth key, to prevent excessive sideward shifting of the keys.
The bottom section where buttons are depressed to play chords or the like, includes a bus sheet constructed of resilient electrically conductive material. Tabs are formed in the sheet and are bent to extend with an upward incline. A circuit board is provided with contacts positioned below the tabs of the bus sheet, so that the depression of a tab establishes electrical contact between the bus sheet and the circuit board contact. Each of the manually depressible buttons rests upon one of the tabs to eliminate the need for a spring for each button to bias it upwardly.
The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial perspective, partial block diagram of an electronic organ constructed in accordance with the invention;
FIG. 2 is a view taken on the line 2--2 of FIG. 1;
FIG. 3 is a view taken on the line 3--3 of FIG. 2;
FIG. 4 is a partial perspective view of the key and electrical contact of FIG. 2;
FIG. 4A is a partial sectional view showing the manner of installation of a key in the organ of FIG. 1;
FIG. 5 is a view taken on the line 5--5 of FIG. 1;
FIG. 6 is a partial perspective view of the button region of the organ of FIG. 1; and
FIG. 7 is a partial sectional view taken on the line 7--7 of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates a portion of an electronic organ, which includes a housing 10 with a piano-type keyboard 12 that is played to produce tones of particular pitches and a button section 14 that is used to play chords or other special sounds. The organ includes a signal generating apparatus 15 for generating electrical signals representing sounds to be played, the apparatus generally including a tone generating section 16 for generating tones of particular pitches and a chord generating section 18 for generating chords, rhythmic or accompaniment patterns or other special sounds. A wide variety of devices are available for generating signals, including optical discs with prerecorded sounds thereon that are played by shining light through tracks of the disc. Signals generated by the signal generating apparatus 15 are delivered to switches actuated by keys of the keyboard 12 and buttons of the button section 14.
When one of the keys at 12 or buttons at 14 is depressed, an electrical signal representing a particular tone or chord pattern is delivered to an amplifier 20 which amplifies the signal and delivers it to a loudspeaker 22 to produce an audible sound. While most organs utilize a keyboard and button arrangement which are part of a complete organ, the keyboard and buttons may be a separate unit used with an independent signal generator and an independent amplifier and loudspeaker arrangement. In any case, a large number of independently operable keys and buttons must be provided, and a construction which simplifies the manual switching apparatus provided by the keyboard and button arrangement can significantly reduce the cost of an organ.
As shown in FIG. 2, 3 and 4, each key 24 of the keyboard is an elongated member with a forward portion 26 whose upper surface is depressed by a musician, and a rearward portion 28 which can move a pair of electrical contacts 30, 32 together. The key has a pair of side walls 34, 36, an upper wall 38 and a lower surface 40. The entire key can be formed in a single injection molding. In order to enable pivotal mounting of the key on the organ housing 10, a pair of recesses 42, 43 is formed in the bottom 40 of the key, the recesses extending into the side walls 34, 36. An elongated bar 44 which is mounted on the housing 10, has an upstanding pivot portion 46 which is received in the recesses 42, 43 of the keys to pivotally mount them on the housing. A strip 48 of bearing material such as polyethylene of substantially U-shaped cross-section, is disposed over the top of the pivot portion to reduce friction and noise during pivoting.
The key 24 can pivot up and down within a limited range. A stop 52 mounted on a bracket 54 that is attached to the organ housing, lies within the front portion 28 of the key. When the key is depressed or released to move up, it hits the stop 52, which is constructed of elastomeric material and shaped to provide a minimum of noise.
The use of the elongated bar 46 that extends laterally across the organ housing allows the keys to be easily installed. Such installation is accomplished by engaging the front portion of each key with the stop 52, as shown in FIG. 4A. Such installation may be compared with an often used procedure wherein each key has a hole in it, and a round shaft must be projected through all of the holes of the keys in order to mount them on the organ.
It may be noted that the recesses 42 and 43 in the key are of different shape, one recess 43 being rounded and the other 42 having a straight inner wall 42I. The reason for this is to prevent binding in spite of moderate dimensional variations in the parts. The recess 43 is rounded to resist forward and rearward motion on the bearing strip 48. The flat bearing-engaging wall 42I of the other recess is at the same elevation, but it does not resist forward and rearward motion. Thus, the recess 42 does not act together with recess 43 to fix the angle A between the side of the key and the side of the bearing 48. The stop 52 at the front of the key fixes the position of the key front, and acts together with the rounded recess 43 to fix the angle A between the key and bearing (generally A is about 90°).
The key 24 is biased towards the position shown in FIG. 2, by a resilient strip switch member 56 which is constructed of electrically conductive material. The strip 55 has a rearward end 58 which is mounted by a spacer 60 on the organ housing, and which has a forward end 61 that is free to bend up and down. The forward end 61 is split into three parts, including a pair of side parts 62, 64 which are bent downwardly to press against the rearward end portion 28 of the lever, and a central part 66 whose outer end forms the electrical contact 32. The parts 62, 64 supply the biasing forces which maintain the key 24 in its usual position prior to depression by a musician. When a musician depresses the key 24, the rearward end 28 thereof moves the parts 62, 64 of the strip 56 upwardly. This causes the central part 66 to move upwardly and bring the contact 32 against another contact 30. The strip 56 is electrically connected to one conductor of the tone generator 16 while the contact 30 is connected to the amplifier 20, so that when the contacts 30, 32 touch one another a tone is sounded. The contact 30 is a portion of a sheet 70 of electrically conductive material which is connected to the amplifier 20.
In addition to pivotally mounting the keys 24 and preventing their removal by outward movement, it is necessary to space the keys a slight distance from each other along the width of the keyboard 12. Such spacing is desirable so that the side walls of the keys do not rub against one another in a manner that would prevent smooth pivoting. Although it would be possible to provide separate spacers mounted on the housing, this would necessitate the production and mounting of many additional members, which would increase the cost of the organ. In order to simplify the spacing of the keys, one side wall 36 of each key is provided with ribs or protuberances 72, 74 that are molded thereon at a location near the recess 42 where the key is pivotally mounted on the pivot portion 46 of the bar 44. The protuberances space the keys from one another to prevent rubbing. Of course, the protuberances may rub on the side wall of the next key, but only a minimal frictional torque is created because of the close location of the protuberances to the axis of pivoting.
The housing 10 and keys 24 are constructed so that there is a small clearance such as five thousanths inch between the protuberances 72, 74 of each key and the side wall of the next key, to prevent binding. If a large number of keys, such as 50, were mounted so that only the first and fiftieth key were restrained from sideward shifting, then the accumulated clearances might allow for a large shifting in the position of individual keys. For example, a five thousanths inch clearance for each of 50 keys might allow a key to shift by one-quarter inch if all keys were pushed to one side. To prevent such a large shifting, spacer fingers 76 are provided between groups of keys. As shown in FIG. 5, a spacer finger 76 is provided between every 12 keys 24 along the keyboard. The fingers 76 are portions of a spacer strip 78 that is fixed to the housing 10. For a clearance such as five thousanths inch between keys, the maximum amount of shifting of any key is equal to 12 of such clearances or sixty thousanths inch. This amount of shifting is small enough that it is not readily noticed and does not affect operation of the keyboard. Of course, the spacer fingers can be located between any desired number of keys, but the larger the number, the smaller the number of spacer fingers required, and the more economical the construction of the organ.
FIGS. 6 and 7 show the details of construction of the button section 14 of the organ. To simplify the construction, a bus plate or sheet 80 is provided which is constructed of a resilient electrically conductive material such as beryllium copper. A circuit board sheet 82 is positioned below the bus sheet 80 and is spaced from the bus sheet by spacer rods 84. The bus sheet 80 has many tabs 86 formed therein which are bent to an upward incline. The circuit board 82 has many conductive strips 88, each of which has a contact spot 90 located below one of the tabs 86. When a tab 86 is depressed, it contacts a contact spot 90 to connect one of the conductive strips 88 to the bus sheet 80. Each of the conductive strips 88 is connected to a different output terminal of the chord generator 18. The bus sheet 80 is connected to the common amplifier 20 whose output is delivered to the loudspeaker for generating audible sounds.
A cover 92, shown in FIG. 7, extends over the bus sheet 80 and supports push buttons 94. Each push button 94 has a lower end 96 which rests against a tab 86 of the bus sheet and an upper end 98 that can be depressed by the finger of the musician. When a musician depresses the button 94, the button depresses the tab 86 so that the tab contacts a contact spot 90 of the circuit board to cause a chord or the like to be played. Each of the buttons 94 has a skirt 100 that is held in a guide 102 of the cover to slidably guide the button in up and down movement. The spring force of the tab 86 is utilized to urge the button 94 upwardly until the skirt 100 hits a top wall of the cover. This eliminates the need for a separate spring to upwardly bias each of the buttons. It may be noted that the two rows of tabs near the rearward end 104 of the bus sheet are designed to be operated by rocker arms.
Thus, the invention provides an organ switching arrangement which is simple and easy to install, to enable the production of reliable organs at low cost. The organ utilizes keys that are mounted by merely inserting them and dropping them onto a pivot bar. Fingers are provided between groups of keys to prevent large lateral shifts due to accumulation of clearances. The keys are biased towards their normal position by strips of electrically conductive material which serve to make and break electrical contact when the keys are operated. The button section of the organ utilizes a bus sheet with tabs that provide for a simplified switching arrangement and which eliminate the need for many springs to upwardly bias the push buttons.
Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art and, consequently, it is intended that the claims be interpreted to cover such modifications and equivalents.
1. Field of the Invention
This invention relates to electronic organs.
2. Description of the Prior Art
Electronic organs typically include a large number of tone generators that generate electrical signals representing sounds to be played, an amplifier and loudspeaker arrangement for producing audible sounds, and manually operated switches for selectively connecting the tone generators to the amplifier. The switching arrangement typically includes a piano-like keyboard for coupling sounds representing single tones to the amplifier and a button region where sounds representing chords or the like are coupled to the amplifier. Inasmuch as a large number of manually operated switches must be included, an organ construction which provided for simple and easy installed switches would enable economical production and pricing of the organs.
OBJECTS AND SUMMARY OF THE INVENTION
An object of the present invention is to provide an organ keyboard which utilizes a minimum number of parts, and which can be rapidly assembled.
Another object is to provide an electronic organ which is reliable and economical.
In accordance with one embodiment of the present invention, an electronic organ is provided which includes a piano-type keyboard and button switch section, both of which utilize a minimum number of parts and are easy to install. The piano-type keyboard section includes keys which are molded with recesses on their bottom walls for receiving a pivot bar that pivotally supports them on the organ housing, and which are molded with protuberances on one side wall for spacing each key from the next succeeding key. The keys can be installed by merely dropping them over a long pivot bar mounted on the organ, instead of necessitating the projection of a shaft through the keys. Several fingers are mounted on the organ housing beside every twelfth key, to prevent excessive sideward shifting of the keys.
The bottom section where buttons are depressed to play chords or the like, includes a bus sheet constructed of resilient electrically conductive material. Tabs are formed in the sheet and are bent to extend with an upward incline. A circuit board is provided with contacts positioned below the tabs of the bus sheet, so that the depression of a tab establishes electrical contact between the bus sheet and the circuit board contact. Each of the manually depressible buttons rests upon one of the tabs to eliminate the need for a spring for each button to bias it upwardly.
The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial perspective, partial block diagram of an electronic organ constructed in accordance with the invention;
FIG. 2 is a view taken on the line 2--2 of FIG. 1;
FIG. 3 is a view taken on the line 3--3 of FIG. 2;
FIG. 4 is a partial perspective view of the key and electrical contact of FIG. 2;
FIG. 4A is a partial sectional view showing the manner of installation of a key in the organ of FIG. 1;
FIG. 5 is a view taken on the line 5--5 of FIG. 1;
FIG. 6 is a partial perspective view of the button region of the organ of FIG. 1; and
FIG. 7 is a partial sectional view taken on the line 7--7 of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates a portion of an electronic organ, which includes a housing 10 with a piano-type keyboard 12 that is played to produce tones of particular pitches and a button section 14 that is used to play chords or other special sounds. The organ includes a signal generating apparatus 15 for generating electrical signals representing sounds to be played, the apparatus generally including a tone generating section 16 for generating tones of particular pitches and a chord generating section 18 for generating chords, rhythmic or accompaniment patterns or other special sounds. A wide variety of devices are available for generating signals, including optical discs with prerecorded sounds thereon that are played by shining light through tracks of the disc. Signals generated by the signal generating apparatus 15 are delivered to switches actuated by keys of the keyboard 12 and buttons of the button section 14.
When one of the keys at 12 or buttons at 14 is depressed, an electrical signal representing a particular tone or chord pattern is delivered to an amplifier 20 which amplifies the signal and delivers it to a loudspeaker 22 to produce an audible sound. While most organs utilize a keyboard and button arrangement which are part of a complete organ, the keyboard and buttons may be a separate unit used with an independent signal generator and an independent amplifier and loudspeaker arrangement. In any case, a large number of independently operable keys and buttons must be provided, and a construction which simplifies the manual switching apparatus provided by the keyboard and button arrangement can significantly reduce the cost of an organ.
As shown in FIG. 2, 3 and 4, each key 24 of the keyboard is an elongated member with a forward portion 26 whose upper surface is depressed by a musician, and a rearward portion 28 which can move a pair of electrical contacts 30, 32 together. The key has a pair of side walls 34, 36, an upper wall 38 and a lower surface 40. The entire key can be formed in a single injection molding. In order to enable pivotal mounting of the key on the organ housing 10, a pair of recesses 42, 43 is formed in the bottom 40 of the key, the recesses extending into the side walls 34, 36. An elongated bar 44 which is mounted on the housing 10, has an upstanding pivot portion 46 which is received in the recesses 42, 43 of the keys to pivotally mount them on the housing. A strip 48 of bearing material such as polyethylene of substantially U-shaped cross-section, is disposed over the top of the pivot portion to reduce friction and noise during pivoting.
The key 24 can pivot up and down within a limited range. A stop 52 mounted on a bracket 54 that is attached to the organ housing, lies within the front portion 28 of the key. When the key is depressed or released to move up, it hits the stop 52, which is constructed of elastomeric material and shaped to provide a minimum of noise.
The use of the elongated bar 46 that extends laterally across the organ housing allows the keys to be easily installed. Such installation is accomplished by engaging the front portion of each key with the stop 52, as shown in FIG. 4A. Such installation may be compared with an often used procedure wherein each key has a hole in it, and a round shaft must be projected through all of the holes of the keys in order to mount them on the organ.
It may be noted that the recesses 42 and 43 in the key are of different shape, one recess 43 being rounded and the other 42 having a straight inner wall 42I. The reason for this is to prevent binding in spite of moderate dimensional variations in the parts. The recess 43 is rounded to resist forward and rearward motion on the bearing strip 48. The flat bearing-engaging wall 42I of the other recess is at the same elevation, but it does not resist forward and rearward motion. Thus, the recess 42 does not act together with recess 43 to fix the angle A between the side of the key and the side of the bearing 48. The stop 52 at the front of the key fixes the position of the key front, and acts together with the rounded recess 43 to fix the angle A between the key and bearing (generally A is about 90°).
The key 24 is biased towards the position shown in FIG. 2, by a resilient strip switch member 56 which is constructed of electrically conductive material. The strip 55 has a rearward end 58 which is mounted by a spacer 60 on the organ housing, and which has a forward end 61 that is free to bend up and down. The forward end 61 is split into three parts, including a pair of side parts 62, 64 which are bent downwardly to press against the rearward end portion 28 of the lever, and a central part 66 whose outer end forms the electrical contact 32. The parts 62, 64 supply the biasing forces which maintain the key 24 in its usual position prior to depression by a musician. When a musician depresses the key 24, the rearward end 28 thereof moves the parts 62, 64 of the strip 56 upwardly. This causes the central part 66 to move upwardly and bring the contact 32 against another contact 30. The strip 56 is electrically connected to one conductor of the tone generator 16 while the contact 30 is connected to the amplifier 20, so that when the contacts 30, 32 touch one another a tone is sounded. The contact 30 is a portion of a sheet 70 of electrically conductive material which is connected to the amplifier 20.
In addition to pivotally mounting the keys 24 and preventing their removal by outward movement, it is necessary to space the keys a slight distance from each other along the width of the keyboard 12. Such spacing is desirable so that the side walls of the keys do not rub against one another in a manner that would prevent smooth pivoting. Although it would be possible to provide separate spacers mounted on the housing, this would necessitate the production and mounting of many additional members, which would increase the cost of the organ. In order to simplify the spacing of the keys, one side wall 36 of each key is provided with ribs or protuberances 72, 74 that are molded thereon at a location near the recess 42 where the key is pivotally mounted on the pivot portion 46 of the bar 44. The protuberances space the keys from one another to prevent rubbing. Of course, the protuberances may rub on the side wall of the next key, but only a minimal frictional torque is created because of the close location of the protuberances to the axis of pivoting.
The housing 10 and keys 24 are constructed so that there is a small clearance such as five thousanths inch between the protuberances 72, 74 of each key and the side wall of the next key, to prevent binding. If a large number of keys, such as 50, were mounted so that only the first and fiftieth key were restrained from sideward shifting, then the accumulated clearances might allow for a large shifting in the position of individual keys. For example, a five thousanths inch clearance for each of 50 keys might allow a key to shift by one-quarter inch if all keys were pushed to one side. To prevent such a large shifting, spacer fingers 76 are provided between groups of keys. As shown in FIG. 5, a spacer finger 76 is provided between every 12 keys 24 along the keyboard. The fingers 76 are portions of a spacer strip 78 that is fixed to the housing 10. For a clearance such as five thousanths inch between keys, the maximum amount of shifting of any key is equal to 12 of such clearances or sixty thousanths inch. This amount of shifting is small enough that it is not readily noticed and does not affect operation of the keyboard. Of course, the spacer fingers can be located between any desired number of keys, but the larger the number, the smaller the number of spacer fingers required, and the more economical the construction of the organ.
FIGS. 6 and 7 show the details of construction of the button section 14 of the organ. To simplify the construction, a bus plate or sheet 80 is provided which is constructed of a resilient electrically conductive material such as beryllium copper. A circuit board sheet 82 is positioned below the bus sheet 80 and is spaced from the bus sheet by spacer rods 84. The bus sheet 80 has many tabs 86 formed therein which are bent to an upward incline. The circuit board 82 has many conductive strips 88, each of which has a contact spot 90 located below one of the tabs 86. When a tab 86 is depressed, it contacts a contact spot 90 to connect one of the conductive strips 88 to the bus sheet 80. Each of the conductive strips 88 is connected to a different output terminal of the chord generator 18. The bus sheet 80 is connected to the common amplifier 20 whose output is delivered to the loudspeaker for generating audible sounds.
A cover 92, shown in FIG. 7, extends over the bus sheet 80 and supports push buttons 94. Each push button 94 has a lower end 96 which rests against a tab 86 of the bus sheet and an upper end 98 that can be depressed by the finger of the musician. When a musician depresses the button 94, the button depresses the tab 86 so that the tab contacts a contact spot 90 of the circuit board to cause a chord or the like to be played. Each of the buttons 94 has a skirt 100 that is held in a guide 102 of the cover to slidably guide the button in up and down movement. The spring force of the tab 86 is utilized to urge the button 94 upwardly until the skirt 100 hits a top wall of the cover. This eliminates the need for a separate spring to upwardly bias each of the buttons. It may be noted that the two rows of tabs near the rearward end 104 of the bus sheet are designed to be operated by rocker arms.
Thus, the invention provides an organ switching arrangement which is simple and easy to install, to enable the production of reliable organs at low cost. The organ utilizes keys that are mounted by merely inserting them and dropping them onto a pivot bar. Fingers are provided between groups of keys to prevent large lateral shifts due to accumulation of clearances. The keys are biased towards their normal position by strips of electrically conductive material which serve to make and break electrical contact when the keys are operated. The button section of the organ utilizes a bus sheet with tabs that provide for a simplified switching arrangement and which eliminate the need for many springs to upwardly bias the push buttons.
Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art and, consequently, it is intended that the claims be interpreted to cover such modifications and equivalents.